Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/22/13
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1157 AM CDT MON MAY 20 2013
.AVIATION...
SCATTERED HIGH END MVFR CIGS ACROSS CENTRAL AND WEST SECTIONS
SHOULD CLIMB ABOVE THE MVFR THRESHOLD BY 21Z. TSRA CHANCES WILL
INCREASE FROM WEST TO EAST THROUGH THE PERIOD.
55
&&
.PREV DISCUSSION... /ISSUED 1039 AM CDT MON MAY 20 2013/
UPDATE...
MADE SOME CHANGES TO THE FORECAST FOR TODAY. A LOOK AT THE MORNING
SOUNDING REVEALS A VERY UNSTABLE ATMOSPHERE WITH A RATHER
SIGNIFICANT CAP AROUND 850 MB. IN SPITE OF THAT THERE IS ABUNDANT
MOISTURE PRESENT AND I FELT IT WOULD BE PRUDENT TO INTRODUCE SOME
RELATIVELY LOW POPS FURTHER TO THE SOUTH ACROSS THE CWA TODAY. IN
ADDITION...CLOUD COVER IS A BIT MORE EXTENSIVE THAN PREVIOUSLY
FORECAST AND IT LOOKS LIKE WE WILL CONTINUE TO HAVE MORE THAN
FORECAST FOR THE REST OF THE DAY...SO I UPPED THOSE VALUES AS WELL.
GETTING BACK TO THE ISSUE OF THE UNSTABLE SOUNDING...THE MODELS
ARE HAVING SOME DIFFICULTIES WITH HOW TO HANDLE THE TIMING OF
STORMS THIS AFTERNOON AND TONIGHT. THE ATMOSPHERE IS QUITE
UNSTABLE...SFC BASED CAPE VALUES ARE ABOVE 3000 J/KG IN CENTRAL
ARKANSAS THIS MORNING AND THE HODOGRAPH IS A BIT OMINOUS. I AM
CONCERNED ABOUT THE POTENTIAL FOR THE DEVELOPMENT OF DISCRETE
SUPERCELLS LATER THIS AFTERNOON AND EVENING ACROSS THE NWRN
PORTIONS OF THE FORECAST AREA. WE WILL BE CONDUCTING A SPECIAL
SOUNDING AT 18Z TODAY TO ASSESS HOW THINGS HAVE CHANGED BY MIDDAY.
CONVECTION THAT WAS OCCURRING ACROSS THE NORTHERN PART OF THE
STATE EARLIER THIS MORNING HAS FIZZLED OUT AND WITH THE EXCEPTION
OF CONVECTION ACROSS WESTERN MO...NOT MUCH ELSE IS HAPPENING THIS
MORNING. I CANT HELP BUT WONDER IF UPPER LEVEL JET DYNAMICS ARE
PLAYING A SUPRESSING ROLE THIS MORNING AS SOME MODELS ARE IMPLYING
A JET MAX EXITING OVER NW MO THIS MORNING WITH ANOTHER SPEED MAX
OVER NRN OK THIS MORNING SWINGING AROUND. IF THAT HOLDS UP THE LID
COULD START TO COME OFF THE CONVECTION BY EARLY TO MID AFTERNOON
ACROSS THE NW. 53
PREV DISCUSSION... /ISSUED 620 AM CDT MON MAY 20 2013/
DISCUSSION...
UPDATED TO INCLUDE THE 12Z AVIATION DISCUSSION BELOW...
AVIATION...
A LINE OF SHRA/TSRA IS EXTENDING FROM MO INTO NORTH CENTRAL AR
THIS MORNING...WITH VCTS CONTINUING IN THE TAF FOR THE NRN SITES
THIS MORNING. OTHERWISE...SOME SITES WERE SEEING SOME MVFR
CIGS...WHICH SHOULD IMPROVE TO VFR LEVELS OUTSIDE ANY PRECIP
ACTIVITY LATER THIS MORNING. ALSO...SOME AREAS EARLY IN THE PERIOD
COULD SEE A BIT OF LOW END LLWS...BUT SHOULD IMPROVE AS SFC WINDS
INCREASE LATER THIS MORNING. BREEZY SRLY WINDS WILL BE SEEN TROUGH
THIS AFTERNOON AND EARLY EVENING AS SFC PRESSURE GRADIENT REMAINS
FAIRLY TIGHT ACROSS THE REGION. HAVE MENTIONED VCTS ACROSS THE NRN
SITES THROUGH THIS AFTERNOON AS ADDITIONAL TSRA COULD DEVELOP THIS
AFTERNOON. THIS EVENING AND INTO TUE MORNING...THE POTENTIAL FOR
SHRA/TSRA WILL SPREAD FURTHER SOUTH AND EAST...WITH PROB30 OR VCTS
MENTIONED FOR TSRA POTENTIAL DURING THIS PERIOD OF THE TAF. SOME
MVFR OR LOWER CONDITIONS COULD BE SEEN UNDER THE PRECIP ACTIVITY.
PREV DISCUSSION... /ISSUED 410 AM CDT MON MAY 20 2013/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
STORMS FORMED OVER NORTHEAST OKLAHOMA LATE SUNDAY EVENING...AND
MOVED NORTHEAST INTO SOUTHERN MISSOURI OVERNIGHT. HOWEVER...SHOWERS
HAVE RECENTLY DEVELOPED ALONG THE SOUTHERN EDGE AND ARE MOVING INTO
NORTHERN ARKANSAS. HAVE KEPT SMALL RAIN CHANCES ACROSS THE NORTH
THROUGH THE MORNING HOURS...AS MUCH OF THIS ACTIVITY WILL DISSIPATE
BEFORE NOON.
QUESTION FOR THIS AFTERNOON WILL BE IF ANY DEVELOPMENT OCCURS ON ANY
LINGERING BOUNDARIES LEFT OVER FROM THE OVERNIGHT ACTIVITY. THE NAM
AND NOW THE HRRR IS PICKING UP ON THIS...AHEAD OF ACTIVITY
DEVELOPING OFF LOW LEVEL JET AROUND SUNSET. THIS WILL HAVE TO BE
MONITORED CLOSELY...BECAUSE IF ANY CELL IS DISCRETE...SEVERE WEATHER
WILL BE MAXIMIZED.
THIS EVENING...STORMS WILL FORM ACROSS EASTERN OKLAHOMA INTO
SOUTHERN MISSOURI...AS FRONT INTERACTS WITH LOW LEVEL JET. THE
STORMS WILL SLOWLY MOVE EAST DURING THE LATE EVENING INTO THE
OVERNIGHT HOURS...WITH STRONG TO SEVERE STORMS POSSIBLE. ALSO...WITH
THE SLOW MOTION AND COPIOUS AMOUNTS OF MOISTURE...HEAVY RAINFALL IS
POSSIBLE...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE TONIGHT.
THE FRONT WILL PROGRESS INTO THE STATE TUESDAY...WITH SEVERE
POTENTIAL CONTINUING. HOWEVER...TORNADIC POTENTIAL WILL NOT BE AS
GREAT DUE TO LESSENING SHEAR. FLOODING REMAINS A CONCERN FOR
TUESDAY...AS SEVERAL ROUNDS OF THUNDERSTORMS WILL MOVE ACROSS THE
AREA.
THE RAINFALL WILL BEGIN TO MOVE SOUTHEAST LATE TUESDAY INTO TUESDAY
NIGHT...WITH MUCH OF THE ACTIVITY CONFINED TO THE SOUTHEAST HALF OF
THE STATE WEDNESDAY. HOWEVER...THE FRONT WILL MEANDER AROUND THE
AREA THROUGH THE END OF THE SHORT TERM...WITH SMALL RAIN CHANCES
CONTINUING.
LONG TERM...FRIDAY THROUGH SUNDAY
COLD FRONT WILL HAVE PUSHED INTO THE STATE FROM THE NE AT THE START
OF THE LONG TERM PERIOD...STALLING ACROSS THE STATE FROM NW TO SE.
MENTION SLIGHT CHANCE POPS WITH THIS FRONT OVER THE STATE FOR
FRI...BUT AN UPPER RIDGE TO THE WEST WILL BEGIN TO SHIFT EAST OVER
THE SRN PLAINS AND SRN MS RIVER VALLEY REGION INTO THIS WEEKEND. AS
A RESULT OF THE RIDGING ALOFT...DECREASE POPS INTO THE WEEKEND...AS
WELL AS INCREASING TEMPS ABOVE NORMAL BY LATE IN THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 85 69 80 65 / 20 50 60 80
CAMDEN AR 89 70 87 67 / 10 20 50 70
HARRISON AR 82 66 78 60 / 40 80 70 60
HOT SPRINGS AR 88 71 84 67 / 20 40 60 70
LITTLE ROCK AR 88 70 84 68 / 20 40 60 70
MONTICELLO AR 90 72 88 69 / 10 20 40 60
MOUNT IDA AR 87 70 83 64 / 20 50 60 70
MOUNTAIN HOME AR 83 67 77 61 / 30 80 60 70
NEWPORT AR 87 70 82 67 / 20 40 60 80
PINE BLUFF AR 89 71 86 69 / 10 20 50 70
RUSSELLVILLE AR 85 68 80 63 / 20 60 60 70
SEARCY AR 87 69 82 66 / 20 40 60 70
STUTTGART AR 89 71 85 68 / 10 30 50 70
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...99
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1039 AM CDT MON MAY 20 2013
.UPDATE...
MADE SOME CHANGES TO THE FORECAST FOR TODAY. A LOOK AT THE MORNING
SOUNDING REVEALS A VERY UNSTABLE ATMOSPHERE WITH A RATHER
SIGNIFICANT CAP AROUND 850 MB. IN SPITE OF THAT THERE IS ABUNDANT
MOISTURE PRESENT AND I FELT IT WOULD BE PRUDENT TO INTRODUCE SOME
RELATIVELY LOW POPS FURTHER TO THE SOUTH ACROSS THE CWA TODAY. IN
ADDITION...CLOUD COVER IS A BIT MORE EXTENSIVE THAN PREVIOUSLY
FORECAST AND IT LOOKS LIKE WE WILL CONTINUE TO HAVE MORE THAN
FORECAST FOR THE REST OF THE DAY...SO I UPPED THOSE VALUES AS WELL.
GETTING BACK TO THE ISSUE OF THE UNSTABLE SOUNDING...THE MODELS
ARE HAVING SOME DIFFICULTIES WITH HOW TO HANDLE THE TIMING OF
STORMS THIS AFTERNOON AND TONIGHT. THE ATMOSPHERE IS QUITE
UNSTABLE...SFC BASED CAPE VALUES ARE ABOVE 3000 J/KG IN CENTRAL
ARKANSAS THIS MORNING AND THE HODOGRAPH IS A BIT OMINOUS. I AM
CONCERNED ABOUT THE POTENTIAL FOR THE DEVELOPMENT OF DISCRETE
SUPERCELLS LATER THIS AFTERNOON AND EVENING ACROSS THE NWRN
PORTIONS OF THE FORECAST AREA. WE WILL BE CONDUCTING A SPECIAL
SOUNDING AT 18Z TODAY TO ASSESS HOW THINGS HAVE CHANGED BY MIDDAY.
CONVECTION THAT WAS OCCURRING ACROSS THE NORTHERN PART OF THE
STATE EARLIER THIS MORNING HAS FIZZLED OUT AND WITH THE EXCEPTION
OF CONVECTION ACROSS WESTERN MO...NOT MUCH ELSE IS HAPPENING THIS
MORNING. I CANT HELP BUT WONDER IF UPPER LEVEL JET DYNAMICS ARE
PLAYING A SUPRESSING ROLE THIS MORNING AS SOME MODELS ARE IMPLYING
A JET MAX EXITING OVER NW MO THIS MORNING WITH ANOTHER SPEED MAX
OVER NRN OK THIS MORNING SWINGING AROUND. IF THAT HOLDS UP THE LID
COULD START TO COME OFF THE CONVECTION BY EARLY TO MID AFTERNOON
ACROSS THE NW. 53
&&
.PREV DISCUSSION... /ISSUED 620 AM CDT MON MAY 20 2013/
DISCUSSION...
UPDATED TO INCLUDE THE 12Z AVIATION DISCUSSION BELOW...
AVIATION...
A LINE OF SHRA/TSRA IS EXTENDING FROM MO INTO NORTH CENTRAL AR
THIS MORNING...WITH VCTS CONTINUING IN THE TAF FOR THE NRN SITES
THIS MORNING. OTHERWISE...SOME SITES WERE SEEING SOME MVFR
CIGS...WHICH SHOULD IMPROVE TO VFR LEVELS OUTSIDE ANY PRECIP
ACTIVITY LATER THIS MORNING. ALSO...SOME AREAS EARLY IN THE PERIOD
COULD SEE A BIT OF LOW END LLWS...BUT SHOULD IMPROVE AS SFC WINDS
INCREASE LATER THIS MORNING. BREEZY SRLY WINDS WILL BE SEEN TROUGH
THIS AFTERNOON AND EARLY EVENING AS SFC PRESSURE GRADIENT REMAINS
FAIRLY TIGHT ACROSS THE REGION. HAVE MENTIONED VCTS ACROSS THE NRN
SITES THROUGH THIS AFTERNOON AS ADDITIONAL TSRA COULD DEVELOP THIS
AFTERNOON. THIS EVENING AND INTO TUE MORNING...THE POTENTIAL FOR
SHRA/TSRA WILL SPREAD FURTHER SOUTH AND EAST...WITH PROB30 OR VCTS
MENTIONED FOR TSRA POTENTIAL DURING THIS PERIOD OF THE TAF. SOME
MVFR OR LOWER CONDITIONS COULD BE SEEN UNDER THE PRECIP ACTIVITY.
PREV DISCUSSION... /ISSUED 410 AM CDT MON MAY 20 2013/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
STORMS FORMED OVER NORTHEAST OKLAHOMA LATE SUNDAY EVENING...AND
MOVED NORTHEAST INTO SOUTHERN MISSOURI OVERNIGHT. HOWEVER...SHOWERS
HAVE RECENTLY DEVELOPED ALONG THE SOUTHERN EDGE AND ARE MOVING INTO
NORTHERN ARKANSAS. HAVE KEPT SMALL RAIN CHANCES ACROSS THE NORTH
THROUGH THE MORNING HOURS...AS MUCH OF THIS ACTIVITY WILL DISSIPATE
BEFORE NOON.
QUESTION FOR THIS AFTERNOON WILL BE IF ANY DEVELOPMENT OCCURS ON ANY
LINGERING BOUNDARIES LEFT OVER FROM THE OVERNIGHT ACTIVITY. THE NAM
AND NOW THE HRRR IS PICKING UP ON THIS...AHEAD OF ACTIVITY
DEVELOPING OFF LOW LEVEL JET AROUND SUNSET. THIS WILL HAVE TO BE
MONITORED CLOSELY...BECAUSE IF ANY CELL IS DISCRETE...SEVERE WEATHER
WILL BE MAXIMIZED.
THIS EVENING...STORMS WILL FORM ACROSS EASTERN OKLAHOMA INTO
SOUTHERN MISSOURI...AS FRONT INTERACTS WITH LOW LEVEL JET. THE
STORMS WILL SLOWLY MOVE EAST DURING THE LATE EVENING INTO THE
OVERNIGHT HOURS...WITH STRONG TO SEVERE STORMS POSSIBLE. ALSO...WITH
THE SLOW MOTION AND COPIOUS AMOUNTS OF MOISTURE...HEAVY RAINFALL IS
POSSIBLE...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE TONIGHT.
THE FRONT WILL PROGRESS INTO THE STATE TUESDAY...WITH SEVERE
POTENTIAL CONTINUING. HOWEVER...TORNADIC POTENTIAL WILL NOT BE AS
GREAT DUE TO LESSENING SHEAR. FLOODING REMAINS A CONCERN FOR
TUESDAY...AS SEVERAL ROUNDS OF THUNDERSTORMS WILL MOVE ACROSS THE
AREA.
THE RAINFALL WILL BEGIN TO MOVE SOUTHEAST LATE TUESDAY INTO TUESDAY
NIGHT...WITH MUCH OF THE ACTIVITY CONFINED TO THE SOUTHEAST HALF OF
THE STATE WEDNESDAY. HOWEVER...THE FRONT WILL MEANDER AROUND THE
AREA THROUGH THE END OF THE SHORT TERM...WITH SMALL RAIN CHANCES
CONTINUING.
LONG TERM...FRIDAY THROUGH SUNDAY
COLD FRONT WILL HAVE PUSHED INTO THE STATE FROM THE NE AT THE START
OF THE LONG TERM PERIOD...STALLING ACROSS THE STATE FROM NW TO SE.
MENTION SLIGHT CHANCE POPS WITH THIS FRONT OVER THE STATE FOR
FRI...BUT AN UPPER RIDGE TO THE WEST WILL BEGIN TO SHIFT EAST OVER
THE SRN PLAINS AND SRN MS RIVER VALLEY REGION INTO THIS WEEKEND. AS
A RESULT OF THE RIDGING ALOFT...DECREASE POPS INTO THE WEEKEND...AS
WELL AS INCREASING TEMPS ABOVE NORMAL BY LATE IN THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 85 69 80 65 / 20 50 60 80
CAMDEN AR 89 70 87 67 / 10 20 50 70
HARRISON AR 82 66 78 60 / 40 80 70 60
HOT SPRINGS AR 88 71 84 67 / 20 40 60 70
LITTLE ROCK AR 88 70 84 68 / 20 40 60 70
MONTICELLO AR 90 72 88 69 / 10 20 40 60
MOUNT IDA AR 87 70 83 64 / 20 50 60 70
MOUNTAIN HOME AR 83 67 77 61 / 30 80 60 70
NEWPORT AR 87 70 82 67 / 20 40 60 80
PINE BLUFF AR 89 71 86 69 / 10 20 50 70
RUSSELLVILLE AR 85 68 80 63 / 20 60 60 70
SEARCY AR 87 69 82 66 / 20 40 60 70
STUTTGART AR 89 71 85 68 / 10 30 50 70
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...99
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
620 AM CDT MON MAY 20 2013
.DISCUSSION...
UPDATED TO INCLUDE THE 12Z AVIATION DISCUSSION BELOW...
&&
.AVIATION...
A LINE OF SHRA/TSRA IS EXTENDING FROM MO INTO NORTH CENTRAL AR
THIS MORNING...WITH VCTS CONTINUING IN THE TAF FOR THE NRN SITES
THIS MORNING. OTHERWISE...SOME SITES WERE SEEING SOME MVFR
CIGS...WHICH SHOULD IMPROVE TO VFR LEVELS OUTSIDE ANY PRECIP
ACTIVITY LATER THIS MORNING. ALSO...SOME AREAS EARLY IN THE PERIOD
COULD SEE A BIT OF LOW END LLWS...BUT SHOULD IMPROVE AS SFC WINDS
INCREASE LATER THIS MORNING. BREEZY SRLY WINDS WILL BE SEEN TROUGH
THIS AFTERNOON AND EARLY EVENING AS SFC PRESSURE GRADIENT REMAINS
FAIRLY TIGHT ACROSS THE REGION. HAVE MENTIONED VCTS ACROSS THE NRN
SITES THROUGH THIS AFTERNOON AS ADDITIONAL TSRA COULD DEVELOP THIS
AFTERNOON. THIS EVENING AND INTO TUE MORNING...THE POTENTIAL FOR
SHRA/TSRA WILL SPREAD FURTHER SOUTH AND EAST...WITH PROB30 OR VCTS
MENTIONED FOR TSRA POTENTIAL DURING THIS PERIOD OF THE TAF. SOME
MVFR OR LOWER CONDITIONS COULD BE SEEN UNDER THE PRECIP ACTIVITY.
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT MON MAY 20 2013/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
STORMS FORMED OVER NORTHEAST OKLAHOMA LATE SUNDAY EVENING...AND
MOVED NORTHEAST INTO SOUTHERN MISSOURI OVERNIGHT. HOWEVER...SHOWERS
HAVE RECENTLY DEVELOPED ALONG THE SOUTHERN EDGE AND ARE MOVING INTO
NORTHERN ARKANSAS. HAVE KEPT SMALL RAIN CHANCES ACROSS THE NORTH
THROUGH THE MORNING HOURS...AS MUCH OF THIS ACTIVITY WILL DISSIPATE
BEFORE NOON.
QUESTION FOR THIS AFTERNOON WILL BE IF ANY DEVELOPMENT OCCURS ON ANY
LINGERING BOUNDARIES LEFT OVER FROM THE OVERNIGHT ACTIVITY. THE NAM
AND NOW THE HRRR IS PICKING UP ON THIS...AHEAD OF ACTIVITY
DEVELOPING OFF LOW LEVEL JET AROUND SUNSET. THIS WILL HAVE TO BE
MONITORED CLOSELY...BECAUSE IF ANY CELL IS DISCRETE...SEVERE WEATHER
WILL BE MAXIMIZED.
THIS EVENING...STORMS WILL FORM ACROSS EASTERN OKLAHOMA INTO
SOUTHERN MISSOURI...AS FRONT INTERACTS WITH LOW LEVEL JET. THE
STORMS WILL SLOWLY MOVE EAST DURING THE LATE EVENING INTO THE
OVERNIGHT HOURS...WITH STRONG TO SEVERE STORMS POSSIBLE. ALSO...WITH
THE SLOW MOTION AND COPIOUS AMOUNTS OF MOISTURE...HEAVY RAINFALL IS
POSSIBLE...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE TONIGHT.
THE FRONT WILL PROGRESS INTO THE STATE TUESDAY...WITH SEVERE
POTENTIAL CONTINUING. HOWEVER...TORNADIC POTENTIAL WILL NOT BE AS
GREAT DUE TO LESSENING SHEAR. FLOODING REMAINS A CONCERN FOR
TUESDAY...AS SEVERAL ROUNDS OF THUNDERSTORMS WILL MOVE ACROSS THE
AREA.
THE RAINFALL WILL BEGIN TO MOVE SOUTHEAST LATE TUESDAY INTO TUESDAY
NIGHT...WITH MUCH OF THE ACTIVITY CONFINED TO THE SOUTHEAST HALF OF
THE STATE WEDNESDAY. HOWEVER...THE FRONT WILL MEANDER AROUND THE
AREA THROUGH THE END OF THE SHORT TERM...WITH SMALL RAIN CHANCES
CONTINUING.
LONG TERM...FRIDAY THROUGH SUNDAY
COLD FRONT WILL HAVE PUSHED INTO THE STATE FROM THE NE AT THE START
OF THE LONG TERM PERIOD...STALLING ACROSS THE STATE FROM NW TO SE.
MENTION SLIGHT CHANCE POPS WITH THIS FRONT OVER THE STATE FOR
FRI...BUT AN UPPER RIDGE TO THE WEST WILL BEGIN TO SHIFT EAST OVER
THE SRN PLAINS AND SRN MS RIVER VALLEY REGION INTO THIS WEEKEND. AS
A RESULT OF THE RIDGING ALOFT...DECREASE POPS INTO THE WEEKEND...AS
WELL AS INCREASING TEMPS ABOVE NORMAL BY LATE IN THE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 85 69 80 65 / 20 50 70 70
CAMDEN AR 89 70 87 67 / 10 20 40 70
HARRISON AR 81 66 78 60 / 30 80 70 60
HOT SPRINGS AR 88 71 84 67 / 10 30 60 70
LITTLE ROCK AR 88 70 84 68 / 10 30 60 70
MONTICELLO AR 90 72 88 69 / 10 10 40 70
MOUNT IDA AR 87 70 83 64 / 20 40 60 70
MOUNTAIN HOME AR 82 67 77 61 / 30 80 70 70
NEWPORT AR 86 70 82 67 / 10 40 60 80
PINE BLUFF AR 89 71 86 69 / 10 20 50 70
RUSSELLVILLE AR 85 68 80 63 / 20 50 70 70
SEARCY AR 87 69 82 66 / 10 30 60 70
STUTTGART AR 88 71 85 68 / 10 20 50 70
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...62
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
410 AM CDT MON MAY 20 2013
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
STORMS FORMED OVER NORTHEAST OKLAHOMA LATE SUNDAY EVENING...AND
MOVED NORTHEAST INTO SOUTHERN MISSOURI OVERNIGHT. HOWEVER...SHOWERS
HAVE RECENTLY DEVELOPED ALONG THE SOUTHERN EDGE AND ARE MOVING INTO
NORTHERN ARKANSAS. HAVE KEPT SMALL RAIN CHANCES ACROSS THE NORTH
THROUGH THE MORNING HOURS...AS MUCH OF THIS ACTIVITY WILL DISSIPATE
BEFORE NOON.
QUESTION FOR THIS AFTERNOON WILL BE IF ANY DEVELOPMENT OCCURS ON ANY
LINGERING BOUNDARIES LEFT OVER FROM THE OVERNIGHT ACTIVITY. THE NAM
AND NOW THE HRRR IS PICKING UP ON THIS...AHEAD OF ACTIVITY
DEVELOPING OFF LOW LEVEL JET AROUND SUNSET. THIS WILL HAVE TO BE
MONITORED CLOSELY...BECAUSE IF ANY CELL IS DISCRETE...SEVERE WEATHER
WILL BE MAXIMIZED.
THIS EVENING...STORMS WILL FORM ACROSS EASTERN OKLAHOMA INTO
SOUTHERN MISSOURI...AS FRONT INTERACTS WITH LOW LEVEL JET. THE
STORMS WILL SLOWLY MOVE EAST DURING THE LATE EVENING INTO THE
OVERNIGHT HOURS...WITH STRONG TO SEVERE STORMS POSSIBLE. ALSO...WITH
THE SLOW MOTION AND COPIOUS AMOUNTS OF MOISTURE...HEAVY RAINFALL IS
POSSIBLE...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE STATE TONIGHT.
THE FRONT WILL PROGRESS INTO THE STATE TUESDAY...WITH SEVERE
POTENTIAL CONTINUING. HOWEVER...TORNADIC POTENTIAL WILL NOT BE AS
GREAT DUE TO LESSENING SHEAR. FLOODING REMAINS A CONCERN FOR
TUESDAY...AS SEVERAL ROUNDS OF THUNDERSTORMS WILL MOVE ACROSS THE
AREA.
THE RAINFALL WILL BEGIN TO MOVE SOUTHEAST LATE TUESDAY INTO TUESDAY
NIGHT...WITH MUCH OF THE ACTIVITY CONFINED TO THE SOUTHEAST HALF OF
THE STATE WEDNESDAY. HOWEVER...THE FRONT WILL MEANDER AROUND THE
AREA THROUGH THE END OF THE SHORT TERM...WITH SMALL RAIN CHANCES
CONTINUING.
&&
.LONG TERM...FRIDAY THROUGH SUNDAY
COLD FRONT WILL HAVE PUSHED INTO THE STATE FROM THE NE AT THE START
OF THE LONG TERM PERIOD...STALLING ACROSS THE STATE FROM NW TO SE.
MENTION SLIGHT CHANCE POPS WITH THIS FRONT OVER THE STATE FOR
FRI...BUT AN UPPER RIDGE TO THE WEST WILL BEGIN TO SHIFT EAST OVER
THE SRN PLAINS AND SRN MS RIVER VALLEY REGION INTO THIS WEEKEND. AS
A RESULT OF THE RIDGING ALOFT...DECREASE POPS INTO THE WEEKEND...AS
WELL AS INCREASING TEMPS ABOVE NORMAL BY LATE IN THE FORECAST.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...58 / LONG TERM...62
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1146 PM EDT TUE MAY 21 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO THE AREA OVERNIGHT...THEN
DISSIPATE WEDNESDAY MORNING. A COLD FRONT WILL THEN SLOWLY
APPROACH FROM THE WEST...THEN PASS THROUGH THURSDAY NIGHT INTO
FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE
MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
ADVECTION FOG/STRATUS IS EXPANDING INTO ERN-MOST LONG ISLAND SOUND
AND NEARBY LAND AREAS. WILL HOLD THE COURSE WITH DENSE FOG ADVY
FOR THE FORKS OF LONG ISLAND AND COASTAL SE CT...WITH PATCHY
FOG ELSEWHERE.
WATCHING LINE OF CONVECTION OVER CENTRAL NY STATE...WHICH THE RA
AND HRRR SUGGEST COULD MAKE A RIGHT TURN TOWARD THE CWA LATE
TONIGHT INTO EARLY WED MORNING. CONVECTION APPEARS OUTFLOW-
DOMINATED WHICH SUGGESTS EVENTUAL WEAKENING. HOWEVER...SINCE THAT
OUTFLOW IS SOMEWHAT ALIGNED WITH THE BULK 0-3 KM SHEAR...SOME
REDEVELOPMENT COULD OCCUR CLOSER TO THE HUDSON VALLEY AND INTERIOR
SW CT LATE TONIGHT...SO HAVE CARRIED A SLIGHT CHANCE POP FOR ALL
AREAS LATE TONIGHT INTO WED MORNING.
BACK DOOR FRONT ADVANCING WWD INTO SOUTHERN CT AND EASTERN LONG
ISLAND WILL LEAD TO A COOLER NIGHT THAN ORIGINALLY FORECAST...WITH
LOWER 55-60. IT WILL HOWEVER REMAIN WARM AND MUGGY OVER THE
HUDSON VALLEY...NYC METRO AND LONG ISLAND...WITH LOWS IN THE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
LOOKS LIKE A SIMILAR DAY ON WEDNESDAY AS RIDGE SLOWLY SHIFTS
EAST. BACK DOOR COLD FRONT SHOULD QUICKLY WASH OUT WITH DAYTIME
HEATING...AND MORNING FOG AND STRATUS WILL GIVE WAY TO AT LEAST
PARTIAL SUNSHINE. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY
MARGINAL INSTABILITY IN PLACE...LESS THAN TODAY. HIGHS IN THE MID
80S...EXCEPT ALONG THE COAST.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY TRANSLATES
EAST THROUGH THE END OF THE WEEK AND THEN OFFSHORE BY THE WEEKEND.
INTERACTION WITH SHORT WAVE ENERGY IN THE NORTHERN BRANCH OF THE
POLAR JET ACROSS EASTERN CANADA WILL AMPLIFY THE TROUGH ACROSS THE
OH VALLEY AND MID ATLANTIC STATES. THIS AMPLIFICATION RESULTS IN
TIMING ISSUES AMONGST THE GLOBAL MODELS...WITH THE OPERATIONAL 12Z
GFS THE SLOWEST AT THE WESTERN END OF THE ENVELOPE. THE ECMWF AND
GGEM ARE THE QUICKEST WITH SWINGING THE FRONT ACROSS THE COAST BY
FRI MORNING. IN FACT...THE GFS CONTINUES TO BECOME MUCH SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW CLOSES OFF
APPROACHING THE MID ATLANTIC STATES...TAKING ON A NEGATIVE TILT
MUCH CLOSER TO THE COAST. THIS WOULD RESULT IN A PROLONGED PERIOD
OF POST-FRONTAL RAIN INTO SAT. PREFERENCE AT THIS TIME WAS TO LEAN
TOWARD THE FASTER MODEL CONSENSUS WITH PCPN SHUTTING DOWN FRI
AFT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO
SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER.
AS FOR THE SENSIBLE WEATHER...COLD FRONT APPROACHES FROM THE WEST
THU...PASSING ACROSS THE REGION THU NIGHT INTO FRI. HIGH PW
VALUES AND MODERATE INSTABILITY WILL LEAD TO THE DEVELOPMENT OF
WIDESPREAD SHOWERS AND THUNDERSTORMS THAT WORK WEST TO EAST
DURING THIS TIME. THE ISOLATED SEVERE THREAT APPEARS LOW AT THIS
TIME WITH THE LOW-LEVEL JET DISPLACED EAST OF THE AREA AND
MARGINAL DEEP LAYER SHEAR. UNIDIRECTIONAL WIND PROFILES SUPPORT
SOME BOWING LINE SEGMENTS WITH GUSTY WINDS. WET-BULB ZERO VALUES ARE
WARM...SUPPORTING ONLY SMALL HAIL. THE MAIN THREAT LOOKS TO BE
THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY IF THE UPPER FLOW
BACKS FURTHER WITH THE AMPLIFICATION OF THE UPPER TROF TO THE
WEST. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH
LOCALIZED HIGHER AMOUNTS.
A DRIER NW FLOW SET UPS FRI NIGHT WITH STRONG COLD ADVECTION. HIGH
PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC
STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES
BELOW SEASONABLE LEVELS.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT WILL REMAIN NORTH ACROSS THE LOWER HUDSON
VALLEY WHILE FARTHER EAST THE FRONT WAS MOVING WESTWARD AS A COLD
FRONT. THE FRONT WILL MAKE IT TO AROUND NEW YORK CITY BY MORNING
BEFORE MOVING BACK NORTH DURING THE MORNING.
STRATUS AND FOG WAS BEGINNING TO MOVE IN FROM THE EAST AND WILL MOVE
INTO THE NYC AREA TERMINALS FROM 08Z TO 10Z. CEILINGS AND
VISIBILITIES BECOME IFR AND AS LOW AS VLIFR AT THE COASTAL TERMINALS
ESPECIALLY AFTER 07Z. CONDITIONS IMPROVE EARLY WEDNESDAY
MORNING...13Z TO 15Z. TIMING OF IMPROVEMENT AND CONDITIONS
UNCERTAIN. WIND WILL BE LIGHT FROM THE SOUTH THROUGH THE NIGHT THEN
INCREASE TO 10 TO 15 KT DURING WEDNESDAY.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER 16Z MAINLY NORTH
AND WEST OF THE NEW YORK TERMINALS.
.OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
.WEDNESDAY NIGHT...SCT SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG
AND STRATUS.
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN
FOG AND STRATUS.
.SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR
WITH NW WINDS INCREASING TO 20-30KT.
.SUNDAY...VFR WITH NW WINDS 20-25KT.
&&
.MARINE...
DENSE FOG BEGINNING TO DEVELOP ACROSS THE EASTERN WATERS.
THIS ADVECTION FOG IS EXPECTED TO EXPAND BACK WEST OVERNIGHT.
SHALLOW BACK DOOR COLD FRONT SHOULD BRING SE-E WINDS OVERNIGHT TO
THE ERN-MOST OCEAN WATERS...ALSO LONG ISLAND SOUND AND THE BAYS OF
LONG ISLAND. OTHERWISE...S-SW SUB SCA WINDS SHOULD CONTINUE
THROUGH WED NIGHT. SEAS SHOULD SLOWLY BUILD ON WED...BUT HAVE
UNDERCUT WAVEWATCH TO PREVENT REACHING SCA CRITERIA UNTIL
WEDNESDAY NIGHT. THINKING WITH STRONG INVERSION THAT WIND FORCING
WAS OVERDONE IN THE WW3 FORECAST.
A COLD FRONT WILL MOVE ACROSS THE AREA WATERS FRIDAY MORNING...WITH
HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS COULD BE BELOW
SCA LEVELS BY FRIDAY MORNING...WITH SEAS ON THE OCEAN REMAINING
ABOVE SCA CRITERIA THROUGH MUCH SATURDAY MORNING. UNDERCUT
WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE
FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY
WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS.
&&
.HYDROLOGY...
SLIGHT CHANCE FOR SOME SHOWERS/TSTMS TO ENTER THE AREA LATE
TONIGHT INTO EARLY WED MORNING. SCT SHOWERS/TSTMS LATER WED WILL
BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST
CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD
BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMTS IN TSTMS.
A MORE ORGANIZED EVENT LATE THU INTO FRI SHOULD PRODUCE AVERAGE
BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER
AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS
WHICH COULD RESULT IN FLASH FLOODING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR CTZ011-012.
NY...DENSE FOG ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR NYZ079.
DENSE FOG ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR NYZ081.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR ANZ330-340.
DENSE FOG ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR ANZ345-350-
353.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
701 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WARM FRONT LIFTING THROUGH THE REGION WILL BRING A FEW SHOWERS
OR THUNDERSTORMS TODAY AS IT HEADS INTO CENTRAL NEW ENGLAND. THE
FRONT WILL DROP BACK SOUTH ON TUESDAY RESULTING IN BRIEFLY COOLER
WEATHER...BEFORE WARM AND HUMID CONDITIONS RETURN WEDNESDAY AND
THURSDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS. IT WILL TURN
COOLER AND LESS HUMID NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
7 AM UPDATE...
WARM FRONT PROGRESSING NORTHWARD AND WILL MOVE THROUGH THE REGION
BY LATE MORNING OR MIDDAY AT THE LATEST. TEMPS ALREADY OFF TO A
MILD START WITH READINGS IN THE U50S AND L60S AT 7 AM. TEMPS WILL
SOAR THROUGHT THE 70S TO AROUND 80 THIS AFTERNOON AWAY FROM THE
SHORE. ONCE BOUNDARY LIFTS NORTH OF THE AREA NOT MUCH OF A FOCUS
FOR CONVECTION. IN ADDITION 0-6KM WIND FIELD DROPS BELOW 30 KT
THIS AFTERNOON. THUS ANY CONVECTION WOULD NOT BE ORGANIZED OR
WIDESPREAD. PREVIOUS FORECAST CAPTURES THIS WELL SO NO MAJOR
CHANGES WITH THIS UPDATE.
===================================================================
LAST OF SHOWERS WERE EXITING CAPE COD AND ISLANDS EARLY THIS
MORNING. CLOUDS REMAIN LOCKED IN WITH PATCHY FOG AND DRIZZLE...
WHICH WILL PERSIST THROUGH MID MORNING. THEREAFTER MODEL CROSS
SECTIONS SHOW SOME DRYING THROUGH COLUMN AS WEAK WARM FRONT LIFTS
TO OUR N. THIS SHOULD ALLOW FOR BREAKS OF SUNSHINE TO DEVELOP
LATER THIS MORNING AND THIS AFTERNOON FOR MUCH OF SOUTHERN NEW
ENGLAND. EXCEPTION WILL BE NEAR S COAST...CAPE COD AND ISLANDS
WHERE MARINE LAYER SHOULD HOLD STRONG GIVEN SW FLOW.
POTENTIAL FOR CONVECTION THIS AFTERNOON IS LIMITED BY LACK OF
INSTABILITY AS SB CAPES ONLY FORECAST TO BE AS HIGH AS 500
J/KG...WEAK MID LEVEL LAPSE RATES OF LESS THAN 5C/KM...AND
MARGINAL 0-6KM SHEAR OF 30KT. THAT SAID WE DO EXPECT TO SEE AT
LEAST WIDELY SCATTERED SHOWERS/STORMS DEVELOP ACROSS INTERIOR.
MAINTAINED CHANCE POPS AWAY FROM S COAST...ALTHOUGH BEST CHANCE
LOOKS TO BE ACROSS SW NH AND NW MA. HRRR SHOWS SCATTERED ACTIVITY
DEVELOPING IN THOSE AREAS AFTER 18Z.
CERTAINLY LOOKS LIKE A WARMER AND SOMEWHAT MORE HUMID DAY WITH
HIGHS RANGING FROM 60S ALONG S COAST TO 70S AND LOWER 80S
ELSEWHERE. USED A BLEND OF NAM/GFS MOS.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/...
WARM FRONT STALLS ACROSS CENTRAL NEW ENGLAND TONIGHT. THIS WILL
MAINTAIN LIGHT S/SW FLOW ACROSS REGION AND WITH PLENTY OF LOW
LEVEL MOISTURE...CONFIDENCE IS HIGH ON SEEING LOW CLOUDS/FOG AND
POSSIBLY DRIZZLE SPREAD INLAND FROM COAST. POTENTIAL IS THERE FOR
AREAS OF DENSE FOG...ESPECIALLY AROUND CAPE COD AND ISLANDS.
OTHERWISE NO SIGNIFICANT RAINFALL IS EXPECTED AS BEST DYNAMICS
STAY TO OUR N AND W. RELATIVELY MILD NIGHT WITH LOWS HOLDING IN
50S/LOWER 60S...WHICH IS CLOSER TO NAM MOS.
WEAK UPPER RIDGE BUILDING ACROSS NEW YORK STATE WILL FORCE FRONT
BACK SOUTHWARD TUE AS A BACKDOOR COLD FRONT. MODELS IN GOOD
AGREEMENT IN DROPPING FRONT THROUGH TUE AFTERNOON...BUT GFS SEEMS
TO OVERDO CONVECTION RIDING E ALONG BOUNDARY FROM GREAT LAKES. NAM
SEEMS MUCH MORE REASONABLE IN STABILIZING AIRMASS OVER SOUTHERN
NEW ENGLAND AS FLOW TURNS MORE E/SE AND FOCUSES ANY CONVECTION TO
OUR W/N WHERE IT BECOMES MORE UNSTABLE. WE ARE NOT THINKING WE
WILL SEE MUCH IN WAY OF SHOWERS/STORMS DEVELOP...ALTHOUGH IT IS
POSSIBLE A FEW SHOWERS MAKE IT INTO WESTERN NEW ENGLAND BY END OF
DAY.
SHOULD BE WIDE RANGE IN TEMPERATURES TUE DUE TO ONSHORE FLOW...
FROM LOWER 60S ALONG E MA COASTLINE INCLUDING CAPE COD TO UPPER
70S ACROSS CT RIVER VALLEY. LEANED MORE TOWARD NAM MOS WHICH
CAPTURES THIS WELL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* WARM AND MUGGY WED/THU THEN TURNING COOLER AND LESS HUMID FRI
* SCATTERED SHOWERS AND THUNDERSTORMS WED AND THU
* DRY BUT COOLER THAN NORMAL FOR MEMORIAL DAY WEEKEND
GOOD OVERALL AGREEMENT ON THE LARGE SCALE FLOW INCLUDING FRONTAL
POSITIONS FROM THE 12Z/19 GEFS AND ECENS. BOTH OF THESE ENSEMBLE
DATA SETS HAVE A BACKDOOR FRONT SAGGING SOUTHWARD THROUGH THE
SOUTHERN NEW ENGLAND TUE NIGHT THEN LIFTING NORTH OF THE REGION WED
AND THU WITH TRUE WARM SECTOR OVERSPREADING THE AREA. BOTH ENSEMBLES
OFFER +16C AIRMASS AT 850 MB AND +20C AT 925 MB OVER THE REGION
WED. THUS POTENTIAL FOR TEMPS TO SOAR INTO THE 80S BOTH DAYS IF
SUNSHINE DEVELOPS. IT WILL BE MUGGY AS WELL WITH DEW PTS IN THE 60S.
THIS WILL RESULT IN WARM NIGHTS /WED AND THU/ ALONG WITH PATCHY FOG.
SCATTERED SHOWERS AND THUNDERSTORMS LIKELY BOTH WED AND THU GIVEN
WARM SECTOR OVER THE AREA BOTH DAYS. ALSO MODELS IN GOOD AGREEMENT
ON CONVECTION ALONG OR NEAR THE WARM FRONT TUE EVENING/NIGHT.
CONVECTION WILL BE MORE WIDESPREAD DURING PEAK HEATING HOURS OF THE
AFTERNOON AND LINGERING INTO THE EARLY EVENING BOTH DAYS. ENSEMBLES
SUGGEST INSTABILITY GREATER WED (MEAN CAPE ABOUT 1000J/KG) THAN THU.
HOWEVER APPROACHING COLD FRONT WILL YIELD GREATER FRONTAL
CONVERGENCE THU ALONG WITH STRONGER JET DYNAMICS /0-6KM DEEP LAYER
SHEAR/...SO CONVECTION MAY BE MORE ORGANIZED/NUMEROUS THU THAN WED.
IN ADDITION GEFS SUGGEST INSTABILITY RIDGE ACROSS NY/PA AND NJ.
THEREFORE WESTERN NEW ENGLAND HAS GREATEST RISK FOR STRONG TO
PERHAPS SEVERE TSTMS WED AND THU. GIVEN INSTABILITY AND PWATS OF +1
TO +2 STD HEAVY DOWNPOURS ARE POSSIBLE WITH ANY CONVECTION.
GOOD MODEL AGREEMENT THAT FRONTAL PASSAGE WILL OCCUR SOMETIME LATE
THU OR FRI. 00Z GFS SLOWER WITH FROPA AS IT DEVELOPS A WAVE ALONG
THE FRONT. AT THIS TIME RANGE PREFER NOT TO CHASE A SINGLE
DETERMINISTIC SOLUTION SO WILL FOLLOW PRES PATTERN FROM GEFS AND
ECENS. THIS SUGGEST FRI WILL BE OUR TRANSITION DAY FROM WARM AND
MUGGY TO A DRY...MUCH COOLER AND LESS HUMID AIRMASS FOR MEMORIAL DAY
WEEKEND. IN FACT BY SAT BOTH GEFS AND ECENS HAVE A 1030MB HIGH
SETTLING OVER THE GREAT LAKES WITH CORE OF THIS ANOMALOUS COOL
AIRMASS /850 TEMPS 0C TO +2C/ ACROSS NORTHERN MA/SOUTHWEST NH...THEN
SLOWLY MODERATING BY MON. HENCE MILD DAYS BUT COOL NIGHTS. IN FACT
THERE COULD BE SOME PATCHY FROST ACROSS NORTHWEST MA INTO SOUTHWEST
NH WITH TEMPS DIPPING INTO THE MU30S SAT AND SUN MORNING!
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
7 AM UPDATE...
NO CHANGE TO PREVIOUS FORECAST. FORECAST REMAINS ON TRACK.
MODERATE CONFIDENCE THROUGH TUE.
WIDESPREAD IFR/LIFR THROUGH 12Z IN LOW CLOUDS/FOG/DRIZZLE. GRADUAL
IMPROVEMENT TO MVFR EXPECTED 12Z-15Z AND EVENTUALLY VFR BY 18Z
EXCEPT AROUND CAPE COD AND ISLANDS WHERE IFR LIKELY TO PERSIST ALL
DAY. SCT SHOWERS WILL REFORM ACROSS INTERIOR AFTER 18Z WITH
ISOLATED THUNDER ALSO POSSIBLE.
SHOULD SEE RAPID DETERIORATION THIS EVENING TO IFR/LIFR 23Z-03Z
AS LOW CLOUDS/FOG/DRIZZLE RETURN IN LIGHT ONSHORE FLOW. WILL BE
HARDER FOR IFR TO ERODE TUE WITH PERSISTENT E/SE WIND...BUT EXPECT
ALL BUT CAPE/ISLANDS TO IMPROVE TO MVFR CIGS BY 18Z.
KBOS TERMINAL...MODERATE CONFIDENCE. CONFIDENT ON TIMING OF
IMPROVEMENT THIS MORNING...BUT CIGS MAY ONLY LIFT TO 025 THROUGH
18Z.
KBDL TERMINAL...MODERATE CONFIDENCE. MAY BE 2-3 HOURS TOO FAST ON
IMPROVEMENT TO MVFR CIGS THIS MORNING.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
TUESDAY THROUGH THURSDAY NIGHT...MODERATE CONFIDENCE. VERY
UNSETTLED PATTERN WITH VARIABILITY BETWEEN VFR CONDITIONS AND
MVFR/IFR CONDITIONS IN SHRA/TSRA/FOG. A FEW STRONG TO SEVERE TSTMS
POSSIBLE WED AND THU.
FRIDAY...MODERATE CONFIDENCE. CONDITIONS SHOULD IMPROVE ALONG WITH
A WIND SHIFT FROM WEST TO EAST AS COLD FRONT MOVES THROUGH REGION.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TUE.
WARM FRONT LIFTS N OF COASTAL WATERS TODAY AND STALLS OVER CENTRAL
NEW ENGLAND. LIGHT S/SW FLOW DEVELOPS ACROSS WATERS BUT SEAS
SLOWLY BUILD IN SOUTHERLY SWELL...MOST NOTABLY ACROSS S COASTAL
WATERS WHERE SCA REMAINS POSTED. ALTHOUGH SW FLOW IS MODEST AT
BEST IT SHOULD STILL CREATE STEEP WAVES ON BUZZARDS BAY AND
VINEYARD SOUND DURING OUTGOING TIDE THIS AFTERNOON...SO MAINTAINED
SCA FOR THOSE AREAS AS WELL.
EXPECT AREAS OF DENSE FOG TONIGHT INTO TUE WITH PERSISTENT SW
FLOW...ESPECIALLY AROUND CAPE COD AND ISLANDS. FRONT DROPS BACK S
TUE AND SHIFTS WINDS TO E/SE...SO VSBYS SHOULD IMPROVE TUE
AFTERNOON. SEAS SHOULD BEGIN TO SUBSIDE AS WELL DUE TO DECAYING
SOUTHERLY SWELL.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUESDAY NIGHT... BACKDOOR FRONT SLIPS ACROSS THE AREA WITH NE WINDS
LIKELY OVER THE NORTHERN WATERS AND SW WINDS ACROSS SOUTHERN WATERS.
RAIN AND FOG WILL REDUCE VSBY. MODEST WIND AT BEST WITH MARGINAL
SWELL.
WED AND THU... WARM FRONT LIFTS NORTH OF THE AREA WITH MODEST SSW
WINDS DEVELOPING ACROSS THE WATERS. SSW WINDS MAY INCREASE TO 20-25
KT FROM LATE WED INTO THU AHEAD OF APPROACHING COLD FRONT. SHOWERS
AND TSTMS SHOULD BE MOST NUMEROUS THU WITH APPROACHING COLD FRONT.
FRIDAY...COLD FRONT ALONG WITH WIND SHIFT FROM SSW TO WNW SHOULD
COMMENCE. VSBY WILL IMPROVE WITH THE WIND.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT TUESDAY
FOR ANZ233>235-237.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY
FOR ANZ254>256.
&&
$$
SYNOPSIS...NOCERA/JWD
NEAR TERM...NOCERA/JWD
SHORT TERM...JWD
LONG TERM...NOCERA
AVIATION...NOCERA/JWD
MARINE...NOCERA/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
339 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WARM FRONT LIFTING THROUGH THE REGION WILL BRING A FEW SHOWERS
OR THUNDERSTORMS TODAY AS IT HEADS INTO CENTRAL NEW ENGLAND. THE
FRONT WILL DROP BACK SOUTH ON TUESDAY RESULTING IN BRIEFLY COOLER
WEATHER...BEFORE WARM AND HUMID CONDITIONS RETURN WEDNESDAY AND
THURSDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS. IT WILL TURN
COOLER AND LESS HUMID NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
315 AM UPDATE...
LAST OF SHOWERS WERE EXITING CAPE COD AND ISLANDS EARLY THIS
MORNING. CLOUDS REMAIN LOCKED IN WITH PATCHY FOG AND DRIZZLE...
WHICH WILL PERSIST THROUGH MID MORNING. THEREAFTER MODEL CROSS
SECTIONS SHOW SOME DRYING THROUGH COLUMN AS WEAK WARM FRONT LIFTS
TO OUR N. THIS SHOULD ALLOW FOR BREAKS OF SUNSHINE TO DEVELOP
LATER THIS MORNING AND THIS AFTERNOON FOR MUCH OF SOUTHERN NEW
ENGLAND. EXCEPTION WILL BE NEAR S COAST...CAPE COD AND ISLANDS
WHERE MARINE LAYER SHOULD HOLD STRONG GIVEN SW FLOW.
POTENTIAL FOR CONVECTION THIS AFTERNOON IS LIMITED BY LACK OF
INSTABILITY AS SB CAPES ONLY FORECAST TO BE AS HIGH AS 500
J/KG...WEAK MID LEVEL LAPSE RATES OF LESS THAN 5C/KM...AND
MARGINAL 0-6KM SHEAR OF 30KT. THAT SAID WE DO EXPECT TO SEE AT
LEAST WIDELY SCATTERED SHOWERS/STORMS DEVELOP ACROSS INTERIOR.
MAINTAINED CHANCE POPS AWAY FROM S COAST...ALTHOUGH BEST CHANCE
LOOKS TO BE ACROSS SW NH AND NW MA. HRRR SHOWS SCATTERED ACTIVITY
DEVELOPING IN THOSE AREAS AFTER 18Z.
CERTAINLY LOOKS LIKE A WARMER AND SOMEWHAT MORE HUMID DAY WITH
HIGHS RANGING FROM 60S ALONG S COAST TO 70S AND LOWER 80S
ELSEWHERE. USED A BLEND OF NAM/GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
WARM FRONT STALLS ACROSS CENTRAL NEW ENGLAND TONIGHT. THIS WILL
MAINTAIN LIGHT S/SW FLOW ACROSS REGION AND WITH PLENTY OF LOW
LEVEL MOISTURE...CONFIDENCE IS HIGH ON SEEING LOW CLOUDS/FOG AND
POSSIBLY DRIZZLE SPREAD INLAND FROM COAST. POTENTIAL IS THERE FOR
AREAS OF DENSE FOG...ESPECIALLY AROUND CAPE COD AND ISLANDS.
OTHERWISE NO SIGNIFICANT RAINFALL IS EXPECTED AS BEST DYNAMICS
STAY TO OUR N AND W. RELATIVELY MILD NIGHT WITH LOWS HOLDING IN
50S/LOWER 60S...WHICH IS CLOSER TO NAM MOS.
WEAK UPPER RIDGE BUILDING ACROSS NEW YORK STATE WILL FORCE FRONT
BACK SOUTHWARD TUE AS A BACKDOOR COLD FRONT. MODELS IN GOOD
AGREEMENT IN DROPPING FRONT THROUGH TUE AFTERNOON...BUT GFS SEEMS
TO OVERDO CONVECTION RIDING E ALONG BOUNDARY FROM GREAT LAKES. NAM
SEEMS MUCH MORE REASONABLE IN STABILIZING AIRMASS OVER SOUTHERN
NEW ENGLAND AS FLOW TURNS MORE E/SE AND FOCUSES ANY CONVECTION TO
OUR W/N WHERE IT BECOMES MORE UNSTABLE. WE ARE NOT THINKING WE
WILL SEE MUCH IN WAY OF SHOWERS/STORMS DEVELOP...ALTHOUGH IT IS
POSSIBLE A FEW SHOWERS MAKE IT INTO WESTERN NEW ENGLAND BY END OF
DAY.
SHOULD BE WIDE RANGE IN TEMPERATURES TUE DUE TO ONSHORE FLOW...
FROM LOWER 60S ALONG E MA COASTLINE INCLUDING CAPE COD TO UPPER
70S ACROSS CT RIVER VALLEY. LEANED MORE TOWARD NAM MOS WHICH
CAPTURES THIS WELL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* WARM AND MUGGY WED/THU THEN TURNING COOLER AND LESS HUMID FRI
* SCATTERED SHOWERS AND THUNDERSTORMS WED AND THU
* DRY BUT COOLER THAN NORMAL FOR MEMORIAL DAY WEEKEND
GOOD OVERALL AGREEMENT ON THE LARGE SCALE FLOW INCLUDING FRONTAL
POSITIONS FROM THE 12Z/19 GEFS AND ECENS. BOTH OF THESE ENSEMBLE
DATA SETS HAVE A BACKDOOR FRONT SAGGING SOUTHWARD THROUGH THE
SOUTHERN NEW ENGLAND TUE NIGHT THEN LIFTING NORTH OF THE REGION WED
AND THU WITH TRUE WARM SECTOR OVERSPREADING THE AREA. BOTH ENSEMBLES
OFFER +16C AIRMASS AT 850 MB AND +20C AT 925 MB OVER THE REGION
WED. THUS POTENTIAL FOR TEMPS TO SOAR INTO THE 80S BOTH DAYS IF
SUNSHINE DEVELOPS. IT WILL BE MUGGY AS WELL WITH DEW PTS IN THE 60S.
THIS WILL RESULT IN WARM NIGHTS /WED AND THU/ ALONG WITH PATCHY FOG.
SCATTERED SHOWERS AND THUNDERSTORMS LIKELY BOTH WED AND THU GIVEN
WARM SECTOR OVER THE AREA BOTH DAYS. ALSO MODELS IN GOOD AGREEMENT
ON CONVECTION ALONG OR NEAR THE WARM FRONT TUE EVENING/NIGHT.
CONVECTION WILL BE MORE WIDESPREAD DURING PEAK HEATING HOURS OF THE
AFTERNOON AND LINGERING INTO THE EARLY EVENING BOTH DAYS. ENSEMBLES
SUGGEST INSTABILITY GREATER WED (MEAN CAPE ABOUT 1000J/KG) THAN THU.
HOWEVER APPROACHING COLD FRONT WILL YIELD GREATER FRONTAL
CONVERGENCE THU ALONG WITH STRONGER JET DYNAMICS /0-6KM DEEP LAYER
SHEAR/...SO CONVECTION MAY BE MORE ORGANIZED/NUMEROUS THU THAN WED.
IN ADDITION GEFS SUGGEST INSTABILITY RIDGE ACROSS NY/PA AND NJ.
THEREFORE WESTERN NEW ENGLAND HAS GREATEST RISK FOR STRONG TO
PERHAPS SEVERE TSTMS WED AND THU. GIVEN INSTABILITY AND PWATS OF +1
TO +2 STD HEAVY DOWNPOURS ARE POSSIBLE WITH ANY CONVECTION.
GOOD MODEL AGREEMENT THAT FRONTAL PASSAGE WILL OCCUR SOMETIME LATE
THU OR FRI. 00Z GFS SLOWER WITH FROPA AS IT DEVELOPS A WAVE ALONG
THE FRONT. AT THIS TIME RANGE PREFER NOT TO CHASE A SINGLE
DETERMINISTIC SOLUTION SO WILL FOLLOW PRES PATTERN FROM GEFS AND
ECENS. THIS SUGGEST FRI WILL BE OUR TRANSITION DAY FROM WARM AND
MUGGY TO A DRY...MUCH COOLER AND LESS HUMID AIRMASS FOR MEMORIAL DAY
WEEKEND. IN FACT BY SAT BOTH GEFS AND ECENS HAVE A 1030MB HIGH
SETTLING OVER THE GREAT LAKES WITH CORE OF THIS ANOMALOUS COOL
AIRMASS /850 TEMPS 0C TO +2C/ ACROSS NORTHERN MA/SOUTHWEST NH...THEN
SLOWLY MODERATING BY MON. HENCE MILD DAYS BUT COOL NIGHTS. IN FACT
THERE COULD BE SOME PATCHY FROST ACROSS NORTHWEST MA INTO SOUTHWEST
NH WITH TEMPS DIPPING INTO THE MU30S SAT AND SUN MORNING!
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH TUE.
WIDESPREAD IFR/LIFR THROUGH 12Z IN LOW CLOUDS/FOG/DRIZZLE. GRADUAL
IMPROVEMENT TO MVFR EXPECTED 12Z-15Z AND EVENTUALLY VFR BY 18Z
EXCEPT AROUND CAPE COD AND ISLANDS WHERE IFR LIKELY TO PERSIST ALL
DAY. SCT SHOWERS WILL REFORM ACROSS INTERIOR AFTER 18Z WITH
ISOLATED THUNDER ALSO POSSIBLE.
SHOULD SEE RAPID DETERIORATION THIS EVENING TO IFR/LIFR 23Z-03Z
AS LOW CLOUDS/FOG/DRIZZLE RETURN IN LIGHT ONSHORE FLOW. WILL BE
HARDER FOR IFR TO ERODE TUE WITH PERSISTENT E/SE WIND...BUT EXPECT
ALL BUT CAPE/ISLANDS TO IMPROVE TO MVFR CIGS BY 18Z.
KBOS TERMINAL...MODERATE CONFIDENCE. CONFIDENT ON TIMING OF
IMPROVEMENT THIS MORNING...BUT CIGS MAY ONLY LIFT TO 025 THROUGH
18Z.
KBDL TERMINAL...MODERATE CONFIDENCE. MAY BE 2-3 HOURS TOO FAST ON
IMPROVEMENT TO MVFR CIGS THIS MORNING.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
TUESDAY THROUGH THURSDAY NIGHT...MODERATE CONFIDENCE. VERY
UNSETTLED PATTERN WITH VARIABILITY BETWEEN VFR CONDITIONS AND
MVFR/IFR CONDITIONS IN SHRA/TSRA/FOG. A FEW STRONG TO SEVERE TSTMS
POSSIBLE WED AND THU.
FRIDAY...MODERATE CONFIDENCE. CONDITIONS SHOULD IMPROVE ALONG WITH
A WIND SHIFT FROM WEST TO EAST AS COLD FRONT MOVES THROUGH REGION.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TUE.
WARM FRONT LIFTS N OF COASTAL WATERS TODAY AND STALLS OVER CENTRAL
NEW ENGLAND. LIGHT S/SW FLOW DEVELOPS ACROSS WATERS BUT SEAS
SLOWLY BUILD IN SOUTHERLY SWELL...MOST NOTABLY ACROSS S COASTAL
WATERS WHERE SCA REMAINS POSTED. ALTHOUGH SW FLOW IS MODEST AT
BEST IT SHOULD STILL CREATE STEEP WAVES ON BUZZARDS BAY AND
VINEYARD SOUND DURING OUTGOING TIDE THIS AFTERNOON...SO MAINTAINED
SCA FOR THOSE AREAS AS WELL.
EXPECT AREAS OF DENSE FOG TONIGHT INTO TUE WITH PERSISTENT SW
FLOW...ESPECIALLY AROUND CAPE COD AND ISLANDS. FRONT DROPS BACK S
TUE AND SHIFTS WINDS TO E/SE...SO VSBYS SHOULD IMPROVE TUE
AFTERNOON. SEAS SHOULD BEGIN TO SUBSIDE AS WELL DUE TO DECAYING
SOUTHERLY SWELL.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUESDAY NIGHT... BACKDOOR FRONT SLIPS ACROSS THE AREA WITH NE WINDS
LIKELY OVER THE NORTHERN WATERS AND SW WINDS ACROSS SOUTHERN WATERS.
RAIN AND FOG WILL REDUCE VSBY. MODEST WIND AT BEST WITH MARGINAL
SWELL.
WED AND THU... WARM FRONT LIFTS NORTH OF THE AREA WITH MODEST SSW
WINDS DEVELOPING ACROSS THE WATERS. SSW WINDS MAY INCREASE TO 20-25
KT FROM LATE WED INTO THU AHEAD OF APPROACHING COLD FRONT. SHOWERS
AND TSTMS SHOULD BE MOST NUMEROUS THU WITH APPROACHING COLD FRONT.
FRIDAY...COLD FRONT ALONG WITH WIND SHIFT FROM SSW TO WNW SHOULD
COMMENCE. VSBY WILL IMPROVE WITH THE WIND.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT TUESDAY
FOR ANZ233>235-237.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY
FOR ANZ254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY
FOR ANZ256.
&&
$$
SYNOPSIS...NOCERA/JWD
NEAR TERM...JWD
SHORT TERM...JWD
LONG TERM...NOCERA
AVIATION...NOCERA/JWD
MARINE...NOCERA/JWD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
317 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WARM FRONT LIFTING THROUGH THE REGION WILL BRING A FEW SHOWERS
OR THUNDERSTORMS TODAY AS IT HEADS INTO CENTRAL NEW ENGLAND. THE
FRONT WILL DROP BACK SOUTH ON TUESDAY RESULTING IN BRIEFLY COOLER
WEATHER...BEFORE WARM AND HUMID CONDITIONS RETURN WEDNESDAY AND
THURSDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS. IT WILL TURN
COOLER AND LESS HUMID NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
315 AM UPDATE...
LAST OF SHOWERS WERE EXITING CAPE COD AND ISLANDS EARLY THIS
MORNING. CLOUDS REMAIN LOCKED IN WITH PATCHY FOG AND DRIZZLE...
WHICH WILL PERSIST THROUGH MID MORNING. THEREAFTER MODEL CROSS
SECTIONS SHOW SOME DRYING THROUGH COLUMN AS WEAK WARM FRONT LIFTS
TO OUR N. THIS SHOULD ALLOW FOR BREAKS OF SUNSHINE TO DEVELOP
LATER THIS MORNING AND THIS AFTERNOON FOR MUCH OF SOUTHERN NEW
ENGLAND. EXCEPTION WILL BE NEAR S COAST...CAPE COD AND ISLANDS
WHERE MARINE LAYER SHOULD HOLD STRONG GIVEN SW FLOW.
POTENTIAL FOR CONVECTION THIS AFTERNOON IS LIMITED BY LACK OF
INSTABILITY AS SB CAPES ONLY FORECAST TO BE AS HIGH AS 500
J/KG...WEAK MID LEVEL LAPSE RATES OF LESS THAN 5C/KM...AND
MARGINAL 0-6KM SHEAR OF 30KT. THAT SAID WE DO EXPECT TO SEE AT
LEAST WIDELY SCATTERED SHOWERS/STORMS DEVELOP ACROSS INTERIOR.
MAINTAINED CHANCE POPS AWAY FROM S COAST...ALTHOUGH BEST CHANCE
LOOKS TO BE ACROSS SW NH AND NW MA. HRRR SHOWS SCATTERED ACTIVITY
DEVELOPING IN THOSE AREAS AFTER 18Z.
CERTAINLY LOOKS LIKE A WARMER AND SOMEWHAT MORE HUMID DAY WITH
HIGHS RANGING FROM 60S ALONG S COAST TO 70S AND LOWER 80S
ELSEWHERE. USED A BLEND OF NAM/GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
WARM FRONT STALLS ACROSS CENTRAL NEW ENGLAND TONIGHT. THIS WILL
MAINTAIN LIGHT S/SW FLOW ACROSS REGION AND WITH PLENTY OF LOW
LEVEL MOISTURE...CONFIDENCE IS HIGH ON SEEING LOW CLOUDS/FOG AND
POSSIBLY DRIZZLE SPREAD INLAND FROM COAST. POTENTIAL IS THERE FOR
AREAS OF DENSE FOG...ESPECIALLY AROUND CAPE COD AND ISLANDS.
OTHERWISE NO SIGNIFICANT RAINFALL IS EXPECTED AS BEST DYNAMICS
STAY TO OUR N AND W. RELATIVELY MILD NIGHT WITH LOWS HOLDING IN
50S/LOWER 60S...WHICH IS CLOSER TO NAM MOS.
WEAK UPPER RIDGE BUILDING ACROSS NEW YORK STATE WILL FORCE FRONT
BACK SOUTHWARD TUE AS A BACKDOOR COLD FRONT. MODELS IN GOOD
AGREEMENT IN DROPPING FRONT THROUGH TUE AFTERNOON...BUT GFS SEEMS
TO OVERDO CONVECTION RIDING E ALONG BOUNDARY FROM GREAT LAKES. NAM
SEEMS MUCH MORE REASONABLE IN STABILIZING AIRMASS OVER SOUTHERN
NEW ENGLAND AS FLOW TURNS MORE E/SE AND FOCUSES ANY CONVECTION TO
OUR W/N WHERE IT BECOMES MORE UNSTABLE. WE ARE NOT THINKING WE
WILL SEE MUCH IN WAY OF SHOWERS/STORMS DEVELOP...ALTHOUGH IT IS
POSSIBLE A FEW SHOWERS MAKE IT INTO WESTERN NEW ENGLAND BY END OF
DAY.
SHOULD BE WIDE RANGE IN TEMPERATURES TUE DUE TO ONSHORE FLOW...
FROM LOWER 60S ALONG E MA COASTLINE INCLUDING CAPE COD TO UPPER
70S ACROSS CT RIVER VALLEY. LEANED MORE TOWARD NAM MOS WHICH
CAPTURES THIS WELL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE WED-THU
* COOLER...LESS HUMID FOR THE WEEKEND
MODELS ARE IN DECENT AGREEMENT THROUGH MUCH OF THE LONG TERM. THERE
ARE SOME TIMING DISCREPANCIES THROUGHOUT THE LONG TERM BETWEEN THE
ECMWF AND THE GFS...AS WELL AS THE NAM TUE. THE NAM IS QUICKER THAN
EITHER THE ECMWF OR GFS WITH A WARM FRONT MOVING NORTH THROUGH THE
REGION TUES. THE GFS THEN WHISKS ALONG AND BRINGS LOW PRESSURE
THROUGH QUEBEC MORE QUICKLY WED WITH A COLD FRONT MOVING THROUGH
SOUTHERN NEW ENGLAND SOONER ON THU THAN THE ECMWF. HOWEVER...THE
OVERALL SYNOPTIC PATTERN IS FAIRLY WELL IN LINE THROUGHOUT THE
PERIOD. GENERALLY EXPECTING A MORE UNSETTLED BUT WARMER PATTERN
THROUGH THE WORK WEEK...WITH QUIETER BUT COOLER WEATHER FRIDAY AND
INTO THE WEEKEND.
WEDNESDAY AND THURSDAY...THERE ARE SOME TIMING QUESTIONS HERE
REGARDING THE LOW PRESSURE SYSTEM MOVING THROUGH SOUTHERN CANADA
AND THE ACCOMPANYING COLD FRONT THAT WILL MOVE THROUGH SOUTHERN
NEW ENGLAND. NEITHER THE GFS NOR THE ECMWF HAVE THE COLD FRONT
MOVING THROUGH SOUTHERN NEW ENGLAND UNTIL AFTER MIDNIGHT THURSDAY
NIGHT. HOWEVER...THE DIFFERENCES IN THE POSITION AND PATH OF THE
LOW PRESSURE COULD IMPACT THE AMOUNT OF CLOUDS AS WELL AS THE BEST
PLACE FOR SHOWERS AND THUNDERSTORMS ACROSS THE REGION. FOR NOW
HAVE OPTED FOR HIGH END CHANCE POPS WITH SLIGHT CHANCE TO CHANCE
THUNDER PRETTY MUCH ACROSS THE BOARD. INSTABILITY PARAMETERS ARE
SUCH THAT EXPECT THUNDER TO BE FAIRLY WIDESPREAD.
FRIDAY...AS MENTIONED ABOVE...THE COLD FRONT WILL MOVE THROUGH
SOUTHERN NEW ENGLAND SOMETIME ON FRIDAY...WITH THE GFS BRINGING IT
THROUGH THE AREA BETWEEN MIDNIGHT AND 6 AM AND THE ECMWF BRINGING IT
THROUGH ABOUT MIDDAY. THE TIMING OF THIS FRONT WILL HAVE A LARGE
IMPACT ON THE WEATHER AS MOSTLY CLOUDY SKIES AND WARMER...MORE HUMID
AIR CAN BE FOUND AHEAD OF THE FRONT WHILE CLEARING SKIES AND
COOLER...LESS HUMID AIR WILL MOVE IN BEHIND THE FRONT. IF THIS
OCCURS DURING THE EARLY MORNING...HIGH TEMPERATURES WILL BE LOWER
BUT THE AREA WILL SEE MORE SUN...WHILE IF IT DOESN/T OCCUR UNTIL
MIDDAY COULD SEE WARMER HIGHS BUT LESS SUN.
SATURDAY AND SUNDAY...WITH HIGH PRESSURE DOMINANT OVER SOUTHERN NEW
ENGLAND...EXPECT A PLEASANT WEEKEND WITH HIGH TEMPERATURES A FEW
DEGREES BELOW NORMAL AND SUNNY SKIES.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH TUE.
WIDESPREAD IFR/LIFR THROUGH 12Z IN LOW CLOUDS/FOG/DRIZZLE. GRADUAL
IMPROVEMENT TO MVFR EXPECTED 12Z-15Z AND EVENTUALLY VFR BY 18Z
EXCEPT AROUND CAPE COD AND ISLANDS WHERE IFR LIKELY TO PERSIST ALL
DAY. SCT SHOWERS WILL REFORM ACROSS INTERIOR AFTER 18Z WITH
ISOLATED THUNDER ALSO POSSIBLE.
SHOULD SEE RAPID DETERIORATION THIS EVENING TO IFR/LIFR 23Z-03Z
AS LOW CLOUDS/FOG/DRIZZLE RETURN IN LIGHT ONSHORE FLOW. WILL BE
HARDER FOR IFR TO ERODE TUE WITH PERSISTENT E/SE WIND...BUT EXPECT
ALL BUT CAPE/ISLANDS TO IMPROVE TO MVFR CIGS BY 18Z.
KBOS TERMINAL...MODERATE CONFIDENCE. CONFIDENT ON TIMING OF
IMPROVEMENT THIS MORNING...BUT CIGS MAY ONLY LIFT TO 025 THROUGH
18Z.
KBDL TERMINAL...MODERATE CONFIDENCE. MAY BE 2-3 HOURS TOO FAST ON
IMPROVEMENT TO MVFR CIGS THIS MORNING.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...
WEDNESDAY THROUGH THURSDAY NIGHT...LOW TO MODERATE CONFIDENCE.
VERY UNSETTLED PATTERN WITH VARIABILITY BETWEEN VFR CONDITIONS AND
MVFR/IFR CONDITIONS IN SHRA/TSRA/FOG.
FRIDAY...MODERATE CONFIDENCE. CONDITIONS SHOULD IMPROVE TO VFR FROM
WEST TO EAST AS COLD FRONT MOVES THROUGH REGION.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TUE.
WARM FRONT LIFTS N OF COASTAL WATERS TODAY AND STALLS OVER CENTRAL
NEW ENGLAND. LIGHT S/SW FLOW DEVELOPS ACROSS WATERS BUT SEAS
SLOWLY BUILD IN SOUTHERLY SWELL...MOST NOTABLY ACROSS S COASTAL
WATERS WHERE SCA REMAINS POSTED. ALTHOUGH SW FLOW IS MODEST AT
BEST IT SHOULD STILL CREATE STEEP WAVES ON BUZZARDS BAY AND
VINEYARD SOUND DURING OUTGOING TIDE THIS AFTERNOON...SO MAINTAINED
SCA FOR THOSE AREAS AS WELL.
EXPECT AREAS OF DENSE FOG TONIGHT INTO TUE WITH PERSISTENT SW
FLOW...ESPECIALLY AROUND CAPE COD AND ISLANDS. FRONT DROPS BACK S
TUE AND SHIFTS WINDS TO E/SE...SO VSBYS SHOULD IMPROVE TUE
AFTERNOON. SEAS SHOULD BEGIN TO SUBSIDE AS WELL DUE TO DECAYING
SOUTHERLY SWELL.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...
WEDNESDAY...SEAS INCREASE AS HIGH PRESSURE MOVES AWAY FROM THE
WATERS. SOUTHERLY WINDS GUST TO NEAR 25 KTS. SCA WILL BE NECESSARY
FOR SEAS IF NOT WINDS AS WELL. VISIBILITY MAY BE LIMITED AT TIMES
IN SCATTERED SHOWERS AND THUNDERSTORMS.
THURSDAY...SEAS REMAIN ABOVE 5 FEET AS LOW PRESSURE MOVES INTO THE
MARITIMES AND A COLD FRONT APPROACHES THE WATERS. SOUTHERLY WINDS
GUST TO NEAR 25 KTS. SCA WILL BE NECESSARY FOR SEAS IF NOT WINDS AS
WELL. VISIBILITY MAY BE LIMITED AT TIMES IN SCATTERED SHOWERS AND
THUNDERSTORMS. WINDS INCREASE OVERNIGHT WITH APPROACHING COLD FRONT.
FRIDAY...SEAS BEGIN TO DIMINISH AS HIGH PRESSURE BUILDS OVER THE
WATERS. WINDS INCREASE TO 25 TO 30KTS WITH COLD FRONTAL PASSAGE.
WINDS SHOULD BE OUT OF THE SOUTH AHEAD OF THE FRONT...SHIFTING TO
THE NORTHWEST BEHIND THE FRONT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 6 AM THIS MORNING
TO 2 AM EDT TUESDAY FOR ANZ233>235-237.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY
FOR ANZ254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT TUESDAY
FOR ANZ256.
&&
$$
SYNOPSIS...NOCERA/JWD
NEAR TERM...JWD
SHORT TERM...JWD
LONG TERM...RLG
AVIATION...NOCERA/JWD
MARINE...NOCERA/JWD
AREA FORECAST DISCUSSION
NWS MIAMI FL
949 PM EDT TUE MAY 21 2013
.UPDATE...
UPDATED PRODUCTS EARLIER TO CANCEL FLOOD WATCH BUT HAVE KEPT SCT
POPS GOING THROUGH THE NIGHT. IT APPEARS THAT THE HEAVY RAIN
THREAT IS OVER, BUT WITH THE UPPER LOW STILL IN THE VICINITY
CANNOT RULE OUT A POSSIBLE STORM JUST ABOUT ANYWHERE AT ANY TIME.
LOW LEVEL FLOW CONTINUES SOUTHEASTERLY SO THE GREATEST THREAT WILL
BE THE SOUTHEAST COAST ESPECIALLY IF A LITTLE BIT OF CONVERGENCE
CAN SET UP WITH LESSENING FLOW NEAR THE COAST. THE HRRR CYCLE
SEEMS TO CHANGE EVERY TWO TO THREE HOURS BUT THE LATEST RUN IS
SHOWING QUIET ACTIVITY THROUGH 06Z BUT THE EARLIER RUN HAD SHOWN A
FLARE UP OF CONVECTION LATER TONIGHT ALTHOUGH NOT WIDESPREAD.
KOB
&&
.PREV DISCUSSION... /ISSUED 758 PM EDT TUE MAY 21 2013/
AVIATION...
THE SHOWERS AND SHOULD COME TO AN END OVER SOUTH FLORIDA BY 03Z
TONIGHT AND REMAIN DRY THROUGH 15Z ON WEDNESDAY. SO WILL KEEP VCSH
IN THE ALL OF SOUTH FLORIDA TAF SITES UNTIL 03Z...BEFORE GOING DRY
FOR REST OF TONIGHT. THE WINDS TONIGHT WILL ALSO REMAIN IN A
EASTERLY DIRECTION AT 5 KNOTS OR LESS TONIGHT AT ALL OF THE TAF
SITES.
ON WEDNESDAY...THE WEATHER WILL REMAIN DRY UNTIL 15Z BEFORE
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP OVER SOUTH FLORIDA. SO
WILL PUT IN A VCTS FOR ALL OF SOUTH FLORIDA TAF SITES AFTER 15Z ON
WEDNESDAY. THE EASTERLY WINDS WILL ALSO INCREASE TO AROUND 10
KNOTS WEDNESDAY MORNING AT ALL OF THE TAF SITES AND REMAIN
EASTERLY AT 10 KNOTS THROUGH WEDNESDAY AFTERNOON. THE ONLY
EXCEPTION TO THIS IS AT KAPF TAF SITE...WHERE THE WIND DIRECTION
WILL BECOME WESTERLY DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITION TONIGHT
INTO WEDNESDAY AT ALL OF THE TAF SITES.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 245 PM EDT TUE MAY 21 2013/
.FLOOD WATCH IN EFFECT UNTIL 10 PM EDT THIS EVENING FOR EAST
COAST METRO AREAS...
SHORT TERM...
THE EAST AND WEST COAST SEA BREEZES WERE DEVELOPING ALONG BOTH
COASTS OF SOUTH FLORIDA EARLY THIS AFTERNOON. THESE SEA BREEZES
WILL PUSH SLOWLY INLAND THROUGH THE REST OF THE AFTERNOON HOURS
HELPING TO GENERATE SHOWERS AND THUNDERSTORMS OVER THE AREA. THE
STORMS WILL BE SLOW MOVING THIS AFTERNOON INTO THIS EVENING...AS
THE STEERING FLOW WILL BE LIGHT FROM THE SOUTH AHEAD OF A TROUGH
OF LOW PRESSURE LOCATED OVER THE EASTERN GULF OF MEXICO.
THE GPS-MET SATELLITE IMAGES WHERE SHOWING THE PWAT VALUES TO BE
BETWEEN 1.6 TO 1.7 INCHES EARLY THIS AFTERNOON OVER SOUTH
FLORIDA. THE AVERAGE PWAT VALUE FOR THIS TIME OF YEAR IS AROUND
1.35 INCHES FOR SOUTH FLORIDA. THIS WILL ALLOW FOR HEAVY RAINFALL
OVER SOUTH FLORIDA THIS AFTERNOON INTO THIS EVENING. SO, WILL
CONTINUE TO MENTION HEAVY RAINFALL IN THE FORECAST FOR SOUTH
FLORIDA FOR THIS AFTERNOON INTO THIS EVENING.
THE HEAVY RAINFALL FROM THE STORMS THIS AFTERNOON INTO THIS
EVENING OVER THE EAST COAST METRO AREAS WILL ALLOW FOR SOME
FLOODING TO OCCUR...AS THE GROUNDS ARE VERY SATURATED FROM THE
HEAVY RAINFALL FROM THE STORMS YESTERDAY. THEREFORE...THE FLOOD
WATCH WILL REMAIN IN PLACE OVER THE EAST COAST METRO AREAS THROUGH
LATE THIS EVENING.
THE MID TO UPPER LEVEL TROUGH OVER THE EASTERN GULF OF MEXICO WILL
MOVE EAST TONIGHT THROUGH THE FLORIDA PENINSULA AS THE UPPER LEVEL
LOW OVER NORTHERN FLORIDA MOVES EAST INTO THE WESTERN ATLANTIC
WATERS. THIS WILL ALLOW FOR THE DEEPER MOISTURE OVER SOUTH FLORIDA
TO MOVE EAST INTO THE WESTERN ATLANTIC WATERS ON WEDNESDAY WHICH
WILL ALLOW FOR SOME DRIER AIR TO WORK INTO THE AREA FROM THE
CENTRAL GULF OF MEXICO. THE DRIER AIR WILL STICK AROUND ON
THURSDAY OVER SOUTH FLORIDA. HOWEVER...THERE WILL STILL BE ENOUGH
MOISTURE OVER SOUTH FLORIDA EACH DAY TO ALLOW FOR SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE AREA ON WEDNESDAY
AND THURSDAY ALONG THE SEA BREEZES WITH THE BEST COVERAGE OVER THE
INTERIOR AREAS.
LONG TERM...
A COLD FRONT LOCATED OVER THE CENTRAL UNITED STATES IS FORECAST BY
THE LONG RANGE MODELS TO MOVE SOUTHEAST AND THROUGH SOUTH FLORIDA
EARLY THIS WEEKEND. HIGH PRESSURE SHOULD THEN BUILD INTO THE AREA
FROM THE NORTH LATE THIS WEEKEND INTO EARLY NEXT WEEK. THIS WILL
ALLOW FOR MUCH DRIER AIR TO WORK INTO THE AREA FROM THE NORTH FOR
LATE THIS WEEKEND INTO EARLY NEXT WEEK. SO WILL KEEP A SLIGHT
CHANCE OF POPS OVER SOUTH FLORIDA FOR THE EARLY PART OF THIS
WEEKEND BEFORE GOING DRY FOR THE SECOND HALF OF THIS WEEKEND INTO
EARLY NEXT WEEK.
AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND
PUSH SLOWLY NORTH THROUGH THE AFTERNOON HOURS. SO KEPT VCTS FOR ALL
TAF SITES THROUGH THE AFTERNOON. A FEW SHOWERS MAY MOVE NEAR THE
EAST COAST TAF SITES OVERNIGHT. AN UPPER LEVEL TROUGH WILL SHIFT
EAST TONIGHT INTO WEDNESDAY...PUSHING THE BEST DYNAMICS OVER THE
ATLANTIC WATERS. SO THUNDERSTORM ACTIVITY IS EXPECTED TO START NEAR
THE END OF THE TAF PERIOD ALONG THE SEA BREEZE BOUNDARIES.
MARINE...
THE WINDS WILL BE SOUTHERLY BELOW 10 KNOTS THROUGH LATE THIS
WEEK...BEFORE INCREASING TO BREEZY CONDITIONS FROM THE NORTHEAST
DIRECTION FOR THIS WEEKEND. THIS WILL ALLOW FOR THE SEAS TO REMAIN
BELOW 6 FEET FOR BOTH THE ATLANTIC AND GULF WATERS OF SOUTH
FLORIDA THROUGH LATE THIS WEEK INTO EARLY THIS WEEKEND...BEFORE
INCREASING TO AROUND 6 FEET IN THE GULF STREAM WATERS OF THE
ATLANTIC BY LATE THIS WEEKEND.
FIRE WEATHER...
THE RELATIVE HUMIDITY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL
VALUE OVER SOUTH FLORIDA THROUGH REST OF THIS WEEK. SO NO PROBLEMS
ARE EXPECTED WITH THE FIRE WEATHER OVER SOUTH FLORIDA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 86 74 88 / 40 50 40 30
FORT LAUDERDALE 73 86 77 88 / 40 50 30 30
MIAMI 73 87 76 89 / 40 50 30 30
NAPLES 70 87 71 88 / 30 40 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
308 PM EDT Mon May 20 2013
.NEAR TERM [through tonight]...
The 16 UTC mesoanalysis showed a very weak pressure/wind field
across our forecast area, much like a typical day in the middle of
summer. There were no obvious mesoscale boundaries, but visible
satellite imagery continued to show a cyclonic "twist" near
Tallahassee- probably associated with an MCV from Sunday`s
thunderstorm complex. Vapor imagery and upper air data showed a weak
trough from VA through North FL, with much of our forecast area
under northerly flow aloft on the backside of this trough.
The large scale environment, GFS MOS PoP, and some of the Convection
Allowing Model (CAM) runs suggest that the highest rain chances will
be over our eastern zones, while some of the CAM (like the HRRR and
11 UTC & 12 UTC local WRF runs) continue to forecast scattered
storms across a large portion of our forecast late this afternoon
and evening. The answer is assumed to be somewhere in between,
except that the CAM guidance often has a tendency to be a few hours
late in developing convective cells. Our PoP is 30-40% for most of
our forecast area for the remainder of this afternoon and early
evening. The spatial distribution matches well with the best
thermodynamics, which are most favorable in GA. Although the wind
field is very weak (from the surface to 500 mb), there could be a
few pulse strong to severe storms this afternoon due to the steep
lapse rates. The main threat...though small...will be dime to
quarter size hail and/or microbursts of 50-60 MPH.
&&
.SHORT TERM [Tuesday Through Thursday]...
Slow moving mid level low pressure area will transition into a low
amplitude trough as it shifts slowly ewd across the southeastern
U.S. over the next several days. This will keep unsettled weather
around into at least Thursday with a chance of afternoon showers
and thunderstorms. Rain chances will be a bit greater over our
eastern counties where moisture will be more plentiful. Clouds
and residual outflow boundaries may make afternoon highs a bit
tricky to forecast, however in general expect similar temperatures from
today with highs in the upper 80s to lower 90s and overnight lows
in the 60s. A few stronger storms can not be ruled out each
afternoon, although overall severe threat will remain fairly low.
&&
.LONG TERM [Thursday Night through Monday]...
Unsettled weather pattern will continue into the late part of the
week, but will replaced by drier weather for the weekend as a
slow moving trough finally shifts away from the area. A mid/upper
level ridge of high pressure will begin to establish itself over
the area for the holiday weekend into next week which should
preclude more than isolated afternoon showers/tstms. Temperatures
are expected to remain seasonal with highs in the upper 80s/lower
90s and overnight lows in the 60s.
&&
.AVIATION [through 18Z UTC Tuesday]...
Isolated to scattered TSRA will develop this afternoon, mainly
from 19 UTC through 01 UTC, and mainly around KABY and KVLD where
the probability of rain is 40%. A few storms could produce strong
to severe wind gusts and/or marginally severe hail. The
probability of TSRA elsewhere is 30% or less. Outside of TSRA, VFR
vis and cigs are expected. Patchy fog and/or low clouds are
possible for a brief time Tuesday morning, though confidence is
not high enough to explicitly mention in this TAF package.
&&
.FIRE WEATHER...
Red Flag conditions are not expected for the next several days, as
minimum RH values will likely remain above locally critical levels.
&&
.MARINE...
Pleasant weather and seas will remain the norm through the weekend
with light winds.
&&
.HYDROLOGY...
Unsettled weather pattern will continue into the late week and
support scattered, slow moving thunderstorms each afternoon.
Although some localized flooding could occur with the heavier
storms, overall impacts should remain minor and no meaningful rise
is expected along area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 90 66 89 67 / 30 20 10 40 20
Panama City 70 84 69 83 70 / 20 20 10 20 20
Dothan 68 92 68 92 68 / 30 20 10 30 20
Albany 69 91 69 90 68 / 30 20 30 40 20
Valdosta 66 88 66 87 66 / 30 30 30 50 20
Cross City 66 89 65 87 64 / 30 40 30 40 20
Apalachicola 69 82 68 82 69 / 20 20 10 20 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
SHORT TERM/LONG TERM/MARINE/HYDROLOGY...Evans
REST OF DISCUSSION...Fournier
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1114 AM EDT Mon May 20 2013
.DISCUSSION...
The 12 UTC regional surface analysis showed the western periphery
of the West Atlantic ridge across the Southeast. There appeared to
be an outflow boundary, leftover from Sunday`s thunderstorms in
GA, off the FL Panhandle coast. Visible satellite imagery showed a
well-defined MCV, again leftover from yesterday`s convective
complex, centered over Tallahassee. Vapor imagery and upper air
data showed a ridge axis from Mobile to Ohio, with a weak trough
over the Piedmont. Local radars were quiet so far. Assuming a
surface air parcel of about 90 deg with a dewpoint in the lower to
mid 60s, the SBCAPE at Tallahassee this afternoon would be about
1000 J/Kg.
The large scale environment suggests that the best combination of
deep layer moisture and Q-G forcing will be over our eastern
zones, which is where the statistical guidance consensus has our
highest PoP (30-40% PoP). The 00/06 UTC Convection Allowing Model
(CAM) consensus is on board with this scenario as well. However,
the latest HRRR and 11 UTC local WRF runs indicate more
widespread convection than this, mainly late this afternoon. To
account for this possibility we spread out the PoP more broadly
across our forecast area, with the highest PoP (40%) still being
across South Central GA and North FL.
Mid tropospheric lapse rates were rather high, and most of the
CAPE will be in within the hail growth zone. This suggests the
potential for pulse strong to marginally severe storms later
today, with dime to quarter size hail and microburst wind gusts
of 50 to 60 MPH possible. The weak winds throughout the lower to
mid troposphere will tend to inhibit significant storm
organization and/or updraft rotation, so the coverage and impacts
will be low...about a 5% probability of a severe storm within 25
miles of a point.
&&
.AVIATION [through 18 UTC Tuesday]...
Isolated to scattered TSRA will develop this afternoon, mainly
from 19 UTC through 24 UTC, and mainly around KABY and KVLD where
the probability is 40%. A few storms could produce strong to
severe wind gusts and/or marginally severe hail. The probability
of TSRA elsewhere is 30% or less. Outside of TSRA, VFR vis and
cigs are expected. Patchy fog and/or low clouds are possible for a
brief time Tuesday morning, though confidence is not high enough
to explicitly mention in this TAF package.
&&
.HYDROLOGY...
Only scattered showers and thunderstorms are anticipated over the
next couple of afternoons, and will primarily be confined to areas
east of a line from Tallahassee north to Albany. With weak
steering flow, any storms that do form will have the potential to
meander very slowly or propagate along boundaries. For that
reason, there will remain the potential for isolated nuisance
flooding, but this will have little to no impact on area rivers
and streams.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 90 65 90 66 / 30 30 20 20
Panama City 83 68 84 70 / 20 20 20 10
Dothan 91 67 92 68 / 30 30 20 20
Albany 90 67 91 67 / 40 30 20 20
Valdosta 91 65 88 65 / 40 30 30 20
Cross City 88 65 88 65 / 30 30 40 20
Apalachicola 82 66 82 68 / 20 20 20 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
GA...NONE.
FL...NONE.
GM...NONE.
&&
$$
HYDROLOGY...Harrigan
REST OF DISCUSSION...Fournier
AREA FORECAST DISCUSSION
NWS MIAMI FL
912 AM EDT MON MAY 20 2013
.UPDATE...
HAVE UPDATED GRIDS TO REFLECT CURRENT SHOWER ACTIVITY OVER PALM
BEACH COUNTY, AS WELL AS TWEAKS TO OTHER ELEMENTS. THIS MORNINGS
SOUNDING DOES SHOW THE 500MB TEMP UP TO AROUND -8, WITH A WEAK
CAP. THIS SHOULD ERODE EARLY THIS AFTERNOON, ALLOWING BETTER
DEVELOPMENT OF CONVECTIVE CELLS. SO, MAINLY RAIN SHOWERS THIS
MORNING, WITH POSSIBLY A FEW STRIKES OF LIGHTNING, ALTHOUGH HAVE
YET TO PICK UP ANY THIS MORNING. BUT, THEY CAN NOT BE RULED OUT.
COVERAGE WILL INCREASE LATER TODAY AND SPREAD WESTWARD. THE HRRR IS
SHOWING THAT THE ACTIVITY MAY ACTUALLY BE IN THE WESTERN HALF OF
SOUTH FLORIDA, SO ANOTHER UPDATE MAY BE FORTH COMING LATER THIS
MORNING, IF THE MESOSCALE MODELS CONTINUE TO SHOW THIS TREND OF
CONVECTION OCCURRING TO THE WEST, RATHER THAN THE EAST COAST.
&&
.PREV DISCUSSION... /ISSUED 738 AM EDT MON MAY 20 2013/
AVIATION...
A SHORTWAVE TROUGH COMBINED WITH PLENTY OF MOISTURE...DAYTIME
HEATING AND LIGHT AND VARIABLE LOW-LEVEL FLOW WILL KEEP THE RAINFALL
CHANCES UP TODAY ACROSS SOUTH FLORIDA...ESPECIALLY THROUGH THE
AFTERNOON AND EVENING PERIODS. ADDITIONALLY...A FEW SHOWERS THAT ARE
CURRENTLY DEVELOPING OVER THE OFFSHORE ATLANTIC WATERS WILL CONTINUE
TO TRACK WEST AND MAY BEGIN TO SPREAD ASHORE THROUGH THE MORNING
HOURS. INCLUDED VCSH FOR THE EAST COAST TERMINALS THROUGH THE
MORNING PERIOD AND VCTS THROUGH THE AFTERNOON/EVENING PERIODS FOR
ALL SITES. PERIODS WITH SUB-VFR CONDITIONS WILL REMAIN POSSIBLE IN
AND AROUND THIS ACTIVITY TODAY.
PREV DISCUSSION... /ISSUED 357 AM EDT MON MAY 20 2013/
DISCUSSION...
MAIN FOCUS FOR THIS FORECAST PACKAGE IS THE POSSIBILITY FOR STRONG
TO SEVERE THUNDERSTORMS ACROSS THE AREA THIS AFTERNOON.
DEEPER MOISTURE OVER THE ATLANTIC WATERS CONTINUES TO PRODUCE
ISOLATED SHOWERS EARLY THIS MORNING. THESE SHOWERS SHOULD CONTINUE
TO SLOWLY PUSH TOWARD THE EAST COASTAL AREAS UNDER WEAK EASTERLY
FLOW. HEADING INTO THE PEAK HEATING HOURS OF THE DAY THE FOCUS WILL
SHIFT TO POSSIBLE STRONG TO SEVERE THUNDERSTORM DEVELOPMENT ACROSS
MUCH OF THE AREA. DEEP MOISTURE ADVECTION INTO THE SOUTH FLORIDA
PENINSULA WILL CONTINUE THROUGH THE LATE MORNING AND EARLY AFTERNOON
HOURS. AS A RESULT...MODEL SOUNDINGS DEPICT PWAT VALUES AS HIGH AS
1.75 INCHES. THIS COMBINED WITH WEAK OVERALL STEERING FLOW WILL
ALLOW FOR VERY HEAVY RAINFALL AND THE POSSIBILITY OF LOCALIZED
FLOODING ASSOCIATED WITH ANY STORMS THAT DEVELOP.
THERMODYNAMIC PARAMETERS ARE ALSO EXPECTED TO BE FAVORABLE WITH CAPE
VALUES APPROACHING 3000 J/KG AND LIFTED INDICES RANGING FROM -6C TO
-8C WITH LITTLE IF ANY CAPPING. NORMALLY THIS WOULD BE ENOUGH TO
SPARK A FEW STRONG STORMS...BUT A FAIRLY BROAD H5 SHORTWAVE IS ALSO
EXPECTED TO SLIDE ACROSS THE FLORIDA PENINSULA THIS AFTERNOON WHICH
WILL ACT TO ENHANCE THUNDERSTORM DEVELOPMENT. THIS SHORTWAVE WILL
PROVIDE EXTRA COOLING ALOFT NEEDED FOR STRONG TO SEVERE
THUNDERSTORMS. POINT SOUNDINGS ACROSS THE AREA DEPICT 500 MB
TEMPERATURES AROUND -12C WHICH IS SEVERAL DEGREES COLDER THAN THE
AVERAGE 500 MB TEMPERATURE FOR THIS DATE. ALL OF THESE PARAMETERS
COMBINED WILL AIDE IN THE DEVELOPMENT OF ISOLATED SEVERE
THUNDERSTORMS WITH THE MAIN IMPACTS BEING GUSTY WINDS...LARGE
HAIL...AND LOCALIZED FLOODING. CURRENT THINKING IS THAT
THUNDERSTORMS WILL INITIATE ACROSS THE NORTHERN INTERIOR AND WITH
SUCH WEAK STEERING FLOW...SHOULD BE MAINLY OUTFLOW DRIVEN AND DRIFT
SLOWLY TOWARD THE EAST COAST METRO AREAS.
KEPT CHANCES FOR THUNDERSTORMS OVERNIGHT TONIGHT AND INTO TUESDAY
MORNING AS MID LEVEL DYNAMICS SHOULD PERSIST WITH THE LINGERING
SHORTWAVE. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL BE LIKELY
TUESDAY AFTERNOON BUT 500 MB TEMPERATURES ARE EXPECTED TO BE A BIT
WARMER WITH SLIGHTLY BETTER LOW LEVEL CAPPING. STILL COULD NOT RULE
OUT AN ISOLATED STRONG STORM WITH DIURNAL HEATING AND DEEP MOISTURE
STILL IN PLACE.
AFTERNOON SHOWER AND THUNDERSTORM CHANCES WILL PERSIST THROUGH THE
REMAINDER OF THE WEEK AND INTO THE WEEKEND AS THE H5 SHORTWAVE
LINGERS ACROSS THE FLORIDA PENINSULA. IT IS EXPECTED TO SLOWLY
RETREAT EACH DAY ALLOWING HIGHER H5 HEIGHTS TO SLOWLY BUILD INTO THE
AREA WHILE STILL REMAINING IN A FAIRLY WET PATTERN.
MARINE...
NO MARINE ISSUES ARE EXPECTED OUTSIDE OF ANY THUNDERSTORMS THAT
AFFECT THE LOCAL WATERS. LIGHT TO MODERATE EAST AND SOUTHEAST
WINDS WILL CONTINUE THROUGH AT LEAST THE EARLY HALF OF THE WEEK
ACROSS THE ATLANTIC WATERS WHILE REMAINING MORE LIGHT AND VARIABLE
ACROSS THE GULF WATERS. THROUGH THE LATTER HALF OF THE WEEK WINDS
ARE EXPECTED TO BECOME LIGHT ACROSS ALL LOCAL WATERS.
FIRE WEATHER...
DEEP MOISTURE WILL REMAIN IN PLACE ACROSS THE SOUTH FLORIDA
PENINSULA THROUGH THE PERIOD KEEPING MINIMUM RELATIVE HUMIDITY
LEVELS WELL ABOVE CRITICAL THRESHOLDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 73 86 73 / 60 40 60 40
FORT LAUDERDALE 85 75 86 76 / 60 40 50 40
MIAMI 86 74 87 75 / 50 40 50 30
NAPLES 88 71 88 71 / 30 30 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1052 PM EDT TUE MAY 21 2013
.UPDATE...
UPDATED TO INCLUDE SOME POPS THROUGH MIDNIGHT FOR WEST CENTRAL GA AS
WESTWARD MOVING OUTFLOW BOUNDARY LIKELY TO SPAWN A FEW MORE
THUNDERSTORMS. WATCHING CLOSELY STORMS ACROSS NORTH GA FOR
POSSIBLE LOCALIZED FF THREAT AS WELL. MOST STORMS HAVE BEEN
PRODUCING PEA TO NICKEL SIZED HAIL THIS EVE AND EXPECT TREND TO
CONTINUE THROUGH 4Z TO 5Z.
OTHER UPDATE WAS TO GRIDS WED AFTN AND EVE TO INCLUDE SMALL HAIL
AND GUSTY WINDS AS THERE APPEARS TO BE A MARGINAL SEVERE THREAT
DUE TO SLIGHTLY INCREASING DEEP LAYER SHEAR
PROFILES....PARTICULARLY ACROSS NW AND NE GA. WILL NEED TO MONITOR
FOR POTENTIALLY INCREASING SEVERE THREAT AFTER 3 PM WED.
&&
.PREV DISCUSSION... /ISSUED 805 PM EDT TUE MAY 21 2013/
PREV DISCUSSION... /ISSUED 314 PM EDT TUE MAY 21 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE SHORT TERM. AIRMASS
SHOWERS/TSTORMS DEVELOPING ACROSS THE CWA...MAINLY ACROSS THE
EXTREME NORTH AND EASTERN PARTS OF THE CWA. THESE WILL DISSIPATE
SHORTLY AFTER SUNSET THIS EVENING. THERE IS A POSSIBILITY THAT THE
STORMS OVER NORTHWEST AL AND CENTRAL TN COULD MAKE IT TO EXTREME
NORTHWEST GA BEFORE DIMINISHING THIS EVENING. THE H5 RIDGE OVER THE
EASTERN U.S. WILL WEAKEN AS THE CENTRAL U.S. TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS WILL PUSH A COLD FRONT INTO THE TENNESSEE
VALLEY WEDNESDAY WHICH WILL BRING A BETTER CHANCE OF THUNDERSTORMS
TO THE CWA...MAINLY ACROSS NORTH GA. INSTABILITY INCREASES WEDNESDAY
ACROSS NORTH GA AND THIS COULD PRODUCE A FEW STRONG STORMS. GUIDANCE
TEMPS LOOK GOOD FOR TONIGHT...ALTHOUGH TRICKY FOR WEDNESDAY WITH
ADDITIONAL CLOUDS. WILL TREND TO THE COOLER SIDE OF GUIDANCE ACROSS
NORTH GA FOR HIGHS ON WEDNESDAY DUE TO INCREASED CLOUDS AND PRECIP.
17
LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
BY WEDNESDAY EVENING...BOTH THE GFS AND ECMWF INDICATE THAT THE
FRONT WILL BE WEAKENING SIGNIFICANTLY. GFS REMAINS AB IT ON THE
STRONG SIDE WITH A SLIGHTLY MORE EAST WITH THE GREAT LAKES SURFACE
LOW. BOTH ARE TRANSITIONING THE UPPER LOW TO MORE OF A SHARP OPEN
TROUGH PHASING WITH THE LONGWAVE TROUGH IN CANADA. WEAK SHORTWAVE
OFF THE SOUTH CAROLINA COAST WILL LIFT NORTHEAST AND BE ABSORBED
BY THE LONGWAVE TROUGH AS WELL. SPC CONTINUES THE AREA IN GENERAL
THUNDER FOR THURSDAY...WITH MUCAPE VALUES 500-1000 J/KG EARLY IN
THE DAY...DECREASING BY MID-MORNING...AND INCREASING AGAIN IN
EXTREME SOUTHERN ZONES JUST AHEAD OF THE FRONT AFTER 18Z TO OVER
1000 J/KG. WILL HAVE TO MONITOR THE AREA FOR THE POTENTIAL FOR
ISOLATED STRONG STORMS BUT NOTHING TO SIGNIFICANT.
COLD FRONT SHOULD BE PUSHED THROUGH THE AREA BY LATE THURSDAY...
AND HAVE DECREASED TEMPS NORTHWEST SOMEWHAT TO LINE UP WITH THAT
TIMING A LITTLE BETTER. SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
TOWARD THE END OF THE WEEK WITH SURFACE HIGH PRESSURE BUILDING IN
AND NORTHWEST FLOW ALOFT...CURRENT FORECAST HAS HIGHS ON FRIDAY
ABOUT 5 DEGREES COOLER THAN HIGHS ON THURSDAY EXCEPT IN CENTRAL
GEORGIA. SEE PREVIOUS LONG TERM DISCUSSION BELOW.
TDP
AVIATION...
00Z UPDATE...
MOST OF THE SCATTERED CONVECTION AROUND ATL HAS DIED DOWN WITH
SUNSET...HOWEVER...OUTFLOW BOUNDARY WHICH SHOWS UP ON ATL TDWR AS
WELL AS BOUNDARY ON JGX RADAR NEAR MCN STILL INGNITING A FEW STORMS.
HAVE LEFT TS OUT FOR THE EVENING EXCEPT FOR ATL AND MCN WHICH
SHOULD GET A GLANCING BLOW OF THE CELLS IN EAST GA MOVING SW. HIGH
RES HRRR AND WRF INDICATING SOME DECENT STORM DEVELOPMENT AROUND
THE METRO ATL AIRPORTS BETWEEN 01Z AND 02Z ALONG THE WESTWARD
MOVING OUTFLOW BOUNDARY BUT NOT CONFIDENT ENOUGH IN THAT SCENARIO
TO INSERT INTO TAF...BUT WILL MONITOR FOR POSSIBLE AMD. HAVE
INTRODUCED PROB30 TO ALL TAF SITES TOMORROW AFTERNOON BETWEEN 19Z
AND 20Z AS 4 KM WRF SHOWING CONVECTIVE INITIATION AROUND THAT TIME
AS WEAK COLD FRONT AND REMNANT OUTFLOW MOVE INTO GA. WINDS SHOULD
GO GENERALLY CALM TONIGHT AND PICK UP OUT OF THE SSW BETWEEN 6 TO
10KTS AFTER AROUND 13Z WED.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON CONVECTION THIS EVENING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
KSTELLMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 84 64 84 / 30 40 40 30
ATLANTA 67 83 66 82 / 20 40 40 30
BLAIRSVILLE 60 77 60 78 / 30 60 60 30
CARTERSVILLE 64 84 62 82 / 20 60 60 30
COLUMBUS 68 89 67 87 / 20 30 30 30
GAINESVILLE 65 83 64 81 / 20 50 50 30
MACON 63 87 65 86 / 20 30 30 30
ROME 64 84 61 83 / 30 60 60 30
PEACHTREE CITY 63 85 63 84 / 20 40 30 30
VIDALIA 68 89 69 88 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....SNELSON
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
805 PM EDT TUE MAY 21 2013
.PREV DISCUSSION... /ISSUED 314 PM EDT TUE MAY 21 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE SHORT TERM. AIRMASS
SHOWERS/TSTORMS DEVELOPING ACROSS THE CWA...MAINLY ACROSS THE
EXTREME NORTH AND EASTERN PARTS OF THE CWA. THESE WILL DISSIPATE
SHORTLY AFTER SUNSET THIS EVENING. THERE IS A POSSIBILITY THAT THE
STORMS OVER NORTHWEST AL AND CENTRAL TN COULD MAKE IT TO EXTREME
NORTHWEST GA BEFORE DIMINISHING THIS EVENING. THE H5 RIDGE OVER THE
EASTERN U.S. WILL WEAKEN AS THE CENTRAL U.S. TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS WILL PUSH A COLD FRONT INTO THE TENNESSEE
VALLEY WEDNESDAY WHICH WILL BRING A BETTER CHANCE OF THUNDERSTORMS
TO THE CWA...MAINLY ACROSS NORTH GA. INSTABILITY INCREASES WEDNESDAY
ACROSS NORTH GA AND THIS COULD PRODUCE A FEW STRONG STORMS. GUIDANCE
TEMPS LOOK GOOD FOR TONIGHT...ALTHOUGH TRICKY FOR WEDNESDAY WITH
ADDITIONAL CLOUDS. WILL TREND TO THE COOLER SIDE OF GUIDANCE ACROSS
NORTH GA FOR HIGHS ON WEDNESDAY DUE TO INCREASED CLOUDS AND PRECIP.
17
LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
BY WEDNESDAY EVENING...BOTH THE GFS AND ECMWF INDICATE THAT THE
FRONT WILL BE WEAKENING SIGNIFICANTLY. GFS REMAINS AB IT ON THE
STRONG SIDE WITH A SLIGHTLY MORE EAST WITH THE GREAT LAKES SURFACE
LOW. BOTH ARE TRANSITIONING THE UPPER LOW TO MORE OF A SHARP OPEN
TROUGH PHASING WITH THE LONGWAVE TROUGH IN CANADA. WEAK SHORTWAVE
OFF THE SOUTH CAROLINA COAST WILL LIFT NORTHEAST AND BE ABSORBED
BY THE LONGWAVE TROUGH AS WELL. SPC CONTINUES THE AREA IN GENERAL
THUNDER FOR THURSDAY...WITH MUCAPE VALUES 500-1000 J/KG EARLY IN
THE DAY...DECREASING BY MID-MORNING...AND INCREASING AGAIN IN
EXTREME SOUTHERN ZONES JUST AHEAD OF THE FRONT AFTER 18Z TO OVER
1000 J/KG. WILL HAVE TO MONITOR THE AREA FOR THE POTENTIAL FOR
ISOLATED STRONG STORMS BUT NOTHING TO SIGNIFICANT.
COLD FRONT SHOULD BE PUSHED THROUGH THE AREA BY LATE THURSDAY...
AND HAVE DECREASED TEMPS NORTHWEST SOMEWHAT TO LINE UP WITH THAT
TIMING A LITTLE BETTER. SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
TOWARD THE END OF THE WEEK WITH SURFACE HIGH PRESSURE BUILDING IN
AND NORTHWEST FLOW ALOFT...CURRENT FORECAST HAS HIGHS ON FRIDAY
ABOUT 5 DEGREES COOLER THAN HIGHS ON THURSDAY EXCEPT IN CENTRAL
GEORGIA. SEE PREVIOUS LONG TERM DISCUSSION BELOW.
TDP
&&
.AVIATION...
00Z UPDATE...
MOST OF THE SCATTERED CONVECTION AROUND ATL HAS DIED DOWN WITH
SUNSET...HOWEVER...OUTFLOW BOUNDARY WHICH SHOWS UP ON ATL TDWR AS
WELL AS BOUNDARY ON JGX RADAR NEAR MCN STILL INGNITING A FEW STORMS.
HAVE LEFT TS OUT FOR THE EVENING EXCEPT FOR ATL AND MCN WHICH
SHOULD GET A GLANCING BLOW OF THE CELLS IN EAST GA MOVING SW. HIGH
RES HRRR AND WRF INDICATING SOME DECENT STORM DEVELOPMENT AROUND
THE METRO ATL AIRPORTS BETWEEN 01Z AND 02Z ALONG THE WESTWARD
MOVING OUTFLOW BOUNDARY BUT NOT CONFIDENT ENOUGH IN THAT SCENARIO
TO INSERT INTO TAF...BUT WILL MONITOR FOR POSSIBLE AMD. HAVE
INTRODUCED PROB30 TO ALL TAF SITES TOMORROW AFTERNOON BETWEEN 19Z
AND 20Z AS 4 KM WRF SHOWING CONVECTIVE INITIATION AROUND THAT TIME
AS WEAK COLD FRONT AND REMNANT OUTFLOW MOVE INTO GA. WINDS SHOULD
GO GENERALLY CALM TONIGHT AND PICK UP OUT OF THE SSW BETWEEN 6 TO
10KTS AFTER AROUND 13Z WED.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON CONVECTION THIS EVENING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
KSTELLMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 84 64 84 / 30 40 40 30
ATLANTA 67 83 66 82 / 20 40 40 30
BLAIRSVILLE 60 77 60 78 / 30 60 50 30
CARTERSVILLE 64 84 62 82 / 20 60 40 30
COLUMBUS 68 89 67 87 / 20 30 30 30
GAINESVILLE 65 83 64 81 / 20 50 40 30
MACON 63 87 65 86 / 20 30 30 30
ROME 64 84 61 83 / 30 60 40 30
PEACHTREE CITY 63 85 63 84 / 20 40 30 30
VIDALIA 68 89 69 88 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....SNELSON
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
132 PM EDT MON MAY 20 2013
.SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
/ISSUED AT 328 AM EDT MON MAY 20 2013/
THE IMMEDIATE SHORT TERM WILL BE SPENT DEALING WITH RESULTS OF A
NEARLY 24 HOUR LONG RAINFALL EVENT WHICH INCLUDES THE DEVELOPMENT
OF LOW CLOUDS AND FOG. GENESIS REGION FOR THIS IS THE CAROLINAS
AND OVER THE LAST SEVERAL HOURS HAS SPREAD WEST INTO THE NORTHEAST
MOUNTAINS AND JUST NOW ENTERING INTO THE REMAINDER OF NORTH
GEORGIA. NAM12 VERY BULLISH ON FOG DEVELOPMENT THROUGH THIS
MORNING WITH WIDESPREAD CONDENSATION PRESSURE DEFICIT VALUES RIGHT
AROUND ZERO. GFS NOT NEARLY THIS AGGRESSIVE BUT BASED ON
OBS...LOOKS LIKE NAM12 IS INITIALIZING BETTER AT THIS POINT AND
WILL FAVOR ITS SOLUTION.
FOG AND LOW CLOUDS TO SLOWLY LIFT DURING THE MORNING HOURS BUT
ENOUGH LOW LEVEL MOISTURE REMAINS TO MAINTAIN A CIG DECK FOR MUCH
OF THE DAY. AS FAR AS POPS AREA CONCERNED...MODELS IN AGREEMENT
THAT UPPER RIDGE AXIS WILL SHIFT EASTWARD...GETTING US OUT OF THE
BELT OF NW FLOW AND LIMITING EFFECTS FROM ANY IMPULSES TO OUR
EXTREME EASTERN SECTIONS. AM A LITTLE CONCERNED THAT WEAK SYNOPTIC
WINS WILL ALLOW SEA BREEZE AND DEVELOPING OUTFLOWS PROPAGATE WEST
AND BRING SHOWERS AND THUNDERSTORMS WITH THEM SO HAVE GONE ABOVE
GUIDANCE FORM MY SOUTHEAST ZONES TODAY. HRRR SHOWS SEPARATE
SECTION DEVELOPING DURING THE AFTERNOON. ALTHOUGH THIS REGION IS
CLOSER TO UPPER RIDGE...STRENGTH OF THIS FEATURE IS LIMITED AND
WILL NEED TO CARRY AT LEAST SLIGHT CHANCE POPS ALL ZONES.
LOW CLODS AND FOG NOT QUITE AS PROMINENT IN THE MODELS TUESDAY
MORNING BUT SATELLITE LOOKS LIKE DECENT DEVELOPMENT OVER THE EASTERN
THIRD OF THE REGION...ESPECIALLY THE NORTHEAST MOUNTAINS. THIS
WILL GIVE WAY ONCE AGAIN TO IMPROVING SKY CONDITIONS BY AFTERNOON
BUT POPS LOOK TO BE ON THE INCREASE AGAIN. UPPER RIDGE AXIS
WEAKENS SLIGHTLY IN RESPONSE TO APPROACHING TROUGH.
MEANWHILE...LOW LEVEL INSTABILITY AND LAPSE RATES WILL BE ON THE
INCREASE WITH CAPE VALUES OF NEAR 3000 J/KG PROJECTED LATE
TUESDAY. GIVEN FLOW PATTERN...WOULD EXPECT DEVELOPMENT OVER THE NE
MOUNTAINS FIRST AND THEN PROPAGATING SW TOWARD THE ATLANTA METRO.
HAVE GONE A CONSIDERABLE AMOUNT ABOVE GUIDANCE FOR THESE AREAS.
DEESE
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
/ISSUED AT 328 AM EDT MON MAY 20 2013/
UPPER LEVEL TROUGH APPROACHING ON WEDNESDAY AND COMBINED WITH
ASSOCIATED MOIST AND INSTABILITY WILL GIVE POTENTIAL FOR NUMEROUS
SHOWERS AND SCATTERED THUNDERSTORMS ACROSS MAINLY N GA AND MAINLY
SCATTERED SHOWERS AND STORMS FOR CENTRAL GA. A WEAK COLD FRONT GETS
INTO THE AREA LATE THURSDAY...POSSIBILITY ASSOCIATED WITH SOME UPPER
LEVEL SUPPORT...WILL GIVE THE CHANCE FOR SHOWERS AND STORMS. BEST
MOISTURE AND UPPER SUPPORT DRIFTING EAST ON FRIDAY ALLOWING FOR ONLY
A SLIGHT CHANCE OF SHOWERS AND STORMS. OVERALL MOISTURE AND
INSTABILITY APPEAR LACKING SATURDAY INTO MONDAY AND WHILE PRECIP
POTENTIAL IS NOT ZERO IT LOOKS TO BE LESS THAN 20 PERCENT AT THIS
TIME. TEMPERATURES RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH THE
PERIOD.
BDL
&&
.AVIATION...18Z UPDATE...
MOST CIGS HAVE GONE VFR. A BROKEN DECK MOVING INTO THE ATL AREA
SHOULD RISE ABOVE 3000 BY 18Z AND REMAIN VFR THROUGH THE AFTERNOON.
EXPECT SCATTERED CONVECTION SOUTH OF THE FALL LINE THIS AFTERNOON
BUT THIS SHOULD DISSIPATE AFTER SUNSET. IFR/MVFR CIGS TO REDEVELOP
LATE TONIGHT ACROSS MUCH OF THE AREA WITH 2-5SM WITH FOG. THIS
SHOULD DISSIPATE DURING THE MORNING. WINDS WILL REMAIN LIGHT WITH A
SOUTHWEST COMPONENT FROM CSG-ATL-AHN WHILE MCN HOLDS ON TO A SOUTH
TO SOUTH SOUTH EAST WIND. ALL AREAS GOING NEAR CALM TONIGHT AND THEN
SOUTHWEST AGAIN ON TUESDAY.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON CIGS THIS AFTERNOON AND AFTER 09Z TUE.
HIGH ON REMAINING ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 65 86 64 / 20 5 40 40
ATLANTA 85 68 86 67 / 20 5 30 30
BLAIRSVILLE 82 58 83 63 / 20 5 30 30
CARTERSVILLE 86 65 87 66 / 20 5 20 20
COLUMBUS 88 67 89 67 / 20 10 20 20
GAINESVILLE 83 65 85 66 / 20 5 40 40
MACON 86 64 88 64 / 30 5 30 30
ROME 87 65 88 66 / 20 5 20 20
PEACHTREE CITY 86 62 87 63 / 20 5 30 30
VIDALIA 85 66 87 69 / 40 20 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
745 AM EDT MON MAY 20 2013
.SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
THE IMMEDIATE SHORT TERM WILL BE SPENT DEALING WITH RESULTS OF A
NEARLY 24 HOUR LONG RAINFALL EVENT WHICH INCLUDES THE DEVELOPMENT
OF LOW CLOUDS AND FOG. GENESIS REGION FOR THIS IS THE CAROLINAS
AND OVER THE LAST SEVERAL HOURS HAS SPREAD WEST INTO THE NORTHEAST
MOUNTAINS AND JUST NOW ENTERING INTO THE REMAINDER OF NORTH
GEORGIA. NAM12 VERY BULLISH ON FOG DEVELOPMENT THROUGH THIS
MORNING WITH WIDESPREAD CONDENSATION PRESSURE DEFICIT VALUES RIGHT
AROUND ZERO. GFS NOT NEARLY THIS AGGRESSIVE BUT BASED ON
OBS...LOOKS LIKE NAM12 IS INITIALIZING BETTER AT THIS POINT AND
WILL FAVOR ITS SOLUTION.
FOG AND LOW CLOUDS TO SLOWLY LIFT DURING THE MORNING HOURS BUT
ENOUGH LOW LEVEL MOISTURE REMAINS TO MAINTAIN A CIG DECK FOR MUCH
OF THE DAY. AS FAR AS POPS AREA CONCERNED...MODELS IN AGREEMENT
THAT UPPER RIDGE AXIS WILL SHIFT EASTWARD...GETTING US OUT OF THE
BELT OF NW FLOW AND LIMITING EFFECTS FROM ANY IMPULSES TO OUR
EXTREME EASTERN SECTIONS. AM A LITTLE CONCERNED THAT WEAK SYNOPTIC
WINS WILL ALLOW SEA BREEZE AND DEVELOPING OUTFLOWS PROPAGATE WEST
AND BRING SHOWERS AND THUNDERSTORMS WITH THEM SO HAVE GONE ABOVE
GUIDANCE FORM MY SOUTHEAST ZONES TODAY. HRRR SHOWS SEPARATE
SECTION DEVELOPING DURING THE AFTERNOON. ALTHOUGH THIS REGION IS
CLOSER TO UPPER RIDGE...STRENGTH OF THIS FEATURE IS LIMITED AND
WILL NEED TO CARRY AT LEAST SLIGHT CHANCE POPS ALL ZONES.
LOW CLODS AND FOG NOT QUITE AS PROMINENT IN THE MODELS TUESDAY
MORNING BUT SATELLITE LOOKS LIKE DECENT DEVELOPMENT OVER THE EASTERN
THIRD OF THE REGION...ESPECIALLY THE NORTHEAST MOUNTAINS. THIS
WILL GIVE WAY ONCE AGAIN TO IMPROVING SKY CONDITIONS BY AFTERNOON
BUT POPS LOOK TO BE ON THE INCREASE AGAIN. UPPER RIDGE AXIS
WEAKENS SLIGHTLY IN RESPONSE TO APPROACHING TROUGH.
MEANWHILE...LOW LEVEL INSTABILITY AND LAPSE RATES WILL BE ON THE
INCREASE WITH CAPE VALUES OF NEAR 3000 J/KG PROJECTED LATE
TUESDAY. GIVEN FLOW PATTERN...WOULD EXPECT DEVELOPMENT OVER THE NE
MOUNTAINS FIRST AND THEN PROPAGATING SW TOWARD THE ATLANTA METRO.
HAVE GONE A CONSIDERABLE AMOUNT ABOVE GUIDANCE FOR THESE AREAS.
DEESE
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL TROUGH APPROACHING ON WEDNESDAY AND COMBINED WITH
ASSOCIATED MOIST AND INSTABILITY WILL GIVE POTENTIAL FOR NUMEROUS
SHOWERS AND SCATTERED THUNDERSTORMS ACROSS MAINLY N GA AND MAINLY
SCATTERED SHOWERS AND STORMS FOR CENTRAL GA. A WEAK COLD FRONT GETS
INTO THE AREA LATE THURSDAY...POSSIBILITY ASSOCIATED WITH SOME UPPER
LEVEL SUPPORT...WILL GIVE THE CHANCE FOR SHOWERS AND STORMS. BEST
MOISTURE AND UPPER SUPPORT DRIFTING EAST ON FRIDAY ALLOWING FOR ONLY
A SLIGHT CHANCE OF SHOWERS AND STORMS. OVERALL MOISTURE AND
INSTABILITY APPEAR LACKING SATURDAY INTO MONDAY AND WHILE PRECIP
POTENTIAL IS NOT ZERO IT LOOKS TO BE LESS THAN 20 PERCENT AT THIS
TIME. TEMPERATURES RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH THE
PERIOD.
BDL
&&
.AVIATION...12Z UPDATE...
IFR/LIFR THIS MORNING SHOULD PREVAIL AT THE TERMINAL SITES UNTIL AT
LEAST 14Z...WITH IMPROVEMENT TO VFR BY 17Z. WINDS ARE TRICKY WITH
LIGHT EASTERLY FLOW EXPECTED TO LAST MUCH OF THE MORNING THEN SWITCH
TO SOUTHWEST 5 TO 8 KT BY AFTERNOON. CONVECTION SHOULD REDEVELOP
THIS AFTERNOON BUT WILL BE WIDELY SCATTERED...SO HAVE NOT PUT IN THE
TAFS AT THIS TIME.
//ATL
CONFIDENCE...12Z UPDATE...
MEDIUM ON CIGS AND WINDS.
HIGH ON REMAINING ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 65 86 64 / 20 5 40 40
ATLANTA 85 68 86 67 / 20 5 30 30
BLAIRSVILLE 82 58 83 63 / 20 5 30 30
CARTERSVILLE 86 65 87 66 / 20 5 20 20
COLUMBUS 88 67 89 67 / 20 10 20 20
GAINESVILLE 83 65 85 66 / 20 5 40 40
MACON 86 64 88 64 / 30 5 30 30
ROME 87 65 88 66 / 20 5 20 20
PEACHTREE CITY 86 62 87 63 / 20 5 30 30
VIDALIA 85 66 87 69 / 40 20 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
746 AM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER THE AREA WILL DISSIPATE THROUGH
MID WEEK WHILE ATLANTIC HIGH PRESSURE PREVAILS UNTIL LATE WEEK. A
COLD FRONT WILL DROP THROUGH THE AREA LATE FRIDAY INTO SATURDAY...
FOLLOWED BY HIGH PRESSURE THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SHORTWAVE TROUGH ALOFT OVER THE REGION TODAY IS COMPLEX PER
LOOPS OF OVERNIGHT WATER VAPOR SATELLITE IMAGERY. THE MAIN UPPER
WAVE WAS DRIFTING E ALONG THE VA/NC BORDER WHILE A WEAK VORTICITY
AXIS EXTENDED S OVER COASTAL GEORGIA IN NE FLORIDA. AN INTERESTING
FEATURE IS THE IMPULSE OVER THE FLORIDA PANHANDLE...OUR ANALYSIS
DID NOT DETECT THIS FEATURE AT 500 MB...IT MAY BE PART MCV AND IS
FORECAST TO VERTICALLY STRETCH THE MID LEVEL TROUGH TODAY.
THE MAIN FORECAST PROBLEMS OF THE DAY ARE TWOFOLD. THERE APPEARS TO
BE HEAVY RAIN POTENTIAL UNTIL MID AFTERNOON ALONG COASTAL SOUTH
CAROLINA AND THEN AN ISOLATED SEVERE WEATHER RISK W OF I-95 IN SE
GEORGIA AND FAR SOUTHERN SOUTH CAROLINA THIS AFTERNOON.
ADDRESSING THE MORNING POTENTIAL FOR DEVELOPING CONVECTIVE RAINS
ALONG THE SOUTH CAROLINA COAST...VERY DEEP MOISTURE IS IN PLAY.
LATEST ANALYSIS INDICATES MOISTURE TRANSPORT CONVERGENCE AND A
INSTABILITY GRADIENT HAS SETUP ALONG THE COAST. MOST OF THE 00Z
HIGH RESOLUTION MODELS HAVE PERFORMED POORLY THROUGH 12 HOURS BUT
SHORT LINES OF HEAVY SHOWERS WERE DEVELOPING E OF I-95 IN SOUTH
CAROLINA AND IT LOOKS LIKE SOME POTENTIAL FOR TRAINING CELLS. THE
TRENDS ARE WORTH WATCHING GIVEN THE 1.8 INCH PWATS LURKING ON THE
LATEST RUC ANALYSIS. WE CONTINUED LIKELY POPS IN PARTS OF THE
CHARLESTON TRI-COUNTY AREA.
THE SECOND ISSUE OF THE DAY WILL TURN TO DIURNAL CONVECTIVE
DEVELOPMENT DURING THE AFTERNOON ONCE AGAIN. MODELS INDICATE A 35 KT
700 MB WIND MAX DEVELOPING OVER THE INLAND CAROLINAS AROUND MIDDAY
AND PUNCHING DUE S INTO GEORGIA W OF I-95 LATER TODAY. 300 MB FLOW
ACROSS SE GEORGIA RAPIDLY BACKS FROM SW TO SE TODAY AND A POCKET OF
UPPER DIFLUENCE IS PROGGED...EVEN THOUGH THE FLOW IS WEAK AT JET
LEVEL. MORNING LOW CLOUDS ARE LIKELY TO DISSIPATE LEAVING A
POTENTIAL FOR SOME INSOLATION LATE MORNING AND EARLY AFTERNOON.
MODEL INSTABILITY PROGS SHOW PARAMETERS A BIT MORE UNSTABLE THAN
ON SUNDAY BACK OVER OUR INLAND ZONES. MUCH OF THIS SCENARIO WILL
DEPEND ONCE AGAIN ON MESOSCALE BOUNDARIES AND SURFACE HEATING.
CANNOT RULE OUT ISOLATED SEVERE THUNDERSTORMS WITH DAMAGING WIND
MARGINALLY SEVERE HAIL OR SOME VERY SMALL SCALE CONVECTIVE
ORGANIZATION. MANY OF THESE STORMS WILL ALSO PRODUCE VERY HEAVY
DOWNPOURS.
THE CONFIDENCE OF EITHER OF THESE SCENARIOS BECOMING REALITY IN
SPACE AND TIME IS NOT GREAT...THUS WE OPTED TO NOT ADD ANY MENTIONS
IN OUR HAZARDOUS WEATHER OUTLOOK UNTIL RADAR TRENDS BECOME MORE
DEFINITIVE AND A 12Z ANALYSIS IS PERFORMED.
HIGH TEMPS TODAY 80 TO 85 DEGREES MOST AREAS WITH LIGHT SOUTH TO
SOUTHEAST WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
UPPER LEVEL TROUGHING OVER THE AREA IS NOT GOING ANYWHERE TONIGHT
BUT WE DO EXPECT CONVECTION TO DECREASE IN COVERAGE AND INTENSITY
DURING THE EVENING. LOW LEVEL COASTAL MOISTURE CONVERGENCE WILL
INCREASE TOWARD DAYBREAK ON TUE ALONG COASTAL SOUTH CAROLINA AND
CONVECTIVE RAINS MAY BREAK OUT ONCE AGAIN THERE. WILL ALSO NEED TO
WATCH TRENDS FOR FOG DEVELOPMENT TONIGHT IF CLOUDS BREAK. WITH
WIDESPREAD CONVECTIVE RAINS EXPECTED TODAY...THERE SEEMS TO BE
INCREASING CHANCES FOR FOG...ESPECIALLY INLAND.
A MOIST AIRMASS WILL PERSIST DURING THE PERIOD ALTHOUGH WE SHOULD
SEE A SLIGHT DECREASE IN PW VALUES BY THURSDAY. THE UPPER
SHORTWAVE WILL SLOWLY DISSOLVE OVERHEAD ON TUESDAY BUT ANOTHER
WAVE WILL APPROACH LATE WEDNESDAY THROUGH THURSDAY. AT THE SURFACE
ATLANTIC HIGH PRESSURE WILL MAINTAIN ITS CONTROL...KEEPING
SOUTHERLY FLOW IN LOW-LEVELS AND ALLOWING DAILY SEABREEZE
CIRCULATIONS TO DEVELOP. CONVECTIVE COVERAGE WILL VARY SOMEWHAT
BETWEEN THE THREE DAYS WITH WEDNESDAY CURRENTLY LOOKING LIKE THE
LEAST ACTIVE DAY DUE TO A LACK OF APPRECIABLE UPPER ENERGY TO WORK
WITH. HIGH TEMPS WILL CLIMB INTO THE MID TO UPPER 80S WITH LOWS IN
THE MIDDLE 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
FAIRLY GOOD MODEL CONSISTENCY REGARDING AN UPPER TROUGH SHIFTING
SOUTHEAST AND A COLD FRONTAL PASSAGE FRIDAY OR FRIDAY NIGHT. DRY AND
SLIGHTLY COOLER CANADIAN HIGH PRESSURE LOOKS TO BUILD IN FOR THE
WEEKEND BEFORE SHIFTING OFFSHORE EARLY NEXT WEEK.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
KCHS...A BAND OF SHOWERS WAS DRIFTING TOWARD THE KCHS TERMINAL
THIS MORNING. MODELS CONTINUE TO INDICATE SHOWERS AND ISOLATED
TSTMS INCREASING IN COVERAGE THROUGH MID AFTERNOON WITH THE
SEA BREEZE BECOMING A FOCUS FOR CONVECTION. WE PREVAILED
CONVECTIVE RAINS DURING THE PRIME SEA BREEZE TIME THIS AFTERNOON
WITH VCSH OR TEMPO SHRA UNTIL THEN. TONIGHT...LIKELY VFR BUT
CANNOT RULE OUT MVFR VSBYS LATE IF GROUNDS BECOME WET TODAY.
KSAV...BRIEF MVFR CIGS THIS MORNING BUT CONDITIONS AT DAYBREAK
WERE VFR. THERE COULD BE ADDITIONAL PERIODS OF MVFR CIGS THIS
MORNING OTHERWISE THE MAIN PROBLEM OF THE DAY IS TIMING ANOTHER
BOUT OF DIURNAL CONVECTIVE RAINS. WE MAINTAINED 17Z TO 21Z FROM
PREVIOUS TAFS AS LATEST MODELS ALSO REMAIN CONSISTENT. THERE
COULD BE SOME LOW CLOUDS AND/OR MVFR VSBYS LATE TONIGHT BUT OUR
CONFIDENCE IS LOW AT THIS TIME.
EITHER TERMINAL COULD REPORT THUNDER TODAY AS THE ATMOSPHERE
REMAINS UNSTABLE. WE OPTED TO LEAVE TSRA OUT OF THE PICTURE UNTIL
RADAR TRENDS BECOME BETTER DEFINED.
EXTENDED AVIATION...THE MAIN CONCERN WILL BE SPORADIC REDUCTIONS
IN CEILINGS AND VISIBILITIES...MAINLY ASSOCIATED WITH SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. THE GREATEST CHANCES
WILL BE IN THE AFTERNOON HOURS TUE THROUGH THU...ALTHOUGH EARLY
MORNING FLIGHT RESTRICTIONS CANNOT BE RULED OUT EACH DAY.
&&
.MARINE...
THROUGH TONIGHT...A STRONG RIDGE OF HIGH PRESSURE CENTERED OVER
THE ATLANTIC WILL EXTEND W ACROSS THE COASTAL WATERS...GENERATING
SE AND S WINDS OF 10-15 KT OR LESS AND SEAS IN THE 2-4 FOOT RANGE.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH THURSDAY
NIGHT WITH SEABREEZE CIRCULATIONS DEVELOPING EACH AFTERNOON. A COLD
FRONT WILL DROP THROUGH FRIDAY EVENING OR SATURDAY MORNING WITH A
NORTHEAST FLOW DEVELOPING AS CANADIAN HIGH PRESSURE BUILDS IN. WINDS
AND SEAS WILL LIKELY INCREASE OVER THE WEEKEND IN RESPONSE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
328 AM EDT MON MAY 20 2013
.SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...
THE IMMEDIATE SHORT TERM WILL BE SPENT DEALING WITH RESULTS OF A
NEARLY 24 HOUR LONG RAINFALL EVENT WHICH INCLUDES THE DEVELOPMENT
OF LOW CLOUDS AND FOG. GENESIS REGION FOR THIS IS THE CAROLINAS
AND OVER THE LAST SEVERAL HOURS HAS SPREAD WEST INTO THE NORTHEAST
MOUNTAINS AND JUST NOW ENTERING INTO THE REMAINDER OF NORTH
GEORGIA. NAM12 VERY BULLISH ON FOG DEVELOPMENT THROUGH THIS
MORNING WITH WIDESPREAD CONDENSATION PRESSURE DEFICIT VALUES RIGHT
AROUND ZERO. GFS NOT NEARLY THIS AGGRESSIVE BUT BASED ON
OBS...LOOKS LIKE NAM12 IS INITIALIZING BETTER AT THIS POINT AND
WILL FAVOR ITS SOLUTION.
FOG AND LOW CLOUDS TO SLOWLY LIFT DURING THE MORNING HOURS BUT
ENOUGH LOW LEVEL MOISTURE REMAINS TO MAINTAIN A CIG DECK FOR MUCH
OF THE DAY. AS FAR AS POPS AREA CONCERNED...MODELS IN AGREEMENT
THAT UPPER RIDGE AXIS WILL SHIFT EASTWARD...GETTING US OUT OF THE
BELT OF NW FLOW AND LIMITING EFFECTS FROM ANY IMPULSES TO OUR
EXTREME EASTERN SECTIONS. AM A LITTLE CONCERNED THAT WEAK SYNOPTIC
WINS WILL ALLOW SEA BREEZE AND DEVELOPING OUTFLOWS PROPAGATE WEST
AND BRING SHOWERS AND THUNDERSTORMS WITH THEM SO HAVE GONE ABOVE
GUIDANCE FORM MY SOUTHEAST ZONES TODAY. HRRR SHOWS SEPARATE
SECTION DEVELOPING DURING THE AFTERNOON. ALTHOUGH THIS REGION IS
CLOSER TO UPPER RIDGE...STRENGTH OF THIS FEATURE IS LIMITED AND
WILL NEED TO CARRY AT LEAST SLIGHT CHANCE POPS ALL ZONES.
LOW CLODS AND FOG NOT QUITE AS PROMINENT IN THE MODELS TUESDAY
MORNING BUT SATELLITE LOOKS LIKE DECENT DEVELOPMENT OVER THE EASTERN
THIRD OF THE REGION...ESPECIALLY THE NORTHEAST MOUNTAINS. THIS
WILL GIVE WAY ONCE AGAIN TO IMPROVING SKY CONDITIONS BY AFTERNOON
BUT POPS LOOK TO BE ON THE INCREASE AGAIN. UPPER RIDGE AXIS
WEAKENS SLIGHTLY IN RESPONSE TO APPROACHING TROUGH.
MEANWHILE...LOW LEVEL INSTABILITY AND LAPSE RATES WILL BE ON THE
INCREASE WITH CAPE VALUES OF NEAR 3000 J/KG PROJECTED LATE
TUESDAY. GIVEN FLOW PATTERN...WOULD EXPECT DEVELOPMENT OVER THE NE
MOUNTAINS FIRST AND THEN PROPAGATING SW TOWARD THE ATLANTA METRO.
HAVE GONE A CONSIDERABLE AMOUNT ABOVE GUIDANCE FOR THESE AREAS.
DEESE
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL TROUGH APPROACHING ON WEDNESDAY AND COMBINED WITH
ASSOCIATED MOIST AND INSTABILITY WILL GIVE POTENTIAL FOR NUMEROUS
SHOWERS AND SCATTERED THUNDERSTORMS ACROSS MAINLY N GA AND MAINLY
SCATTERED SHOWERS AND STORMS FOR CENTRAL GA. A WEAK COLD FRONT GETS
INTO THE AREA LATE THURSDAY...POSSIBILITY ASSOCIATED WITH SOME UPPER
LEVEL SUPPORT...WILL GIVE THE CHANCE FOR SHOWERS AND STORMS. BEST
MOISTURE AND UPPER SUPPORT DRIFTING EAST ON FRIDAY ALLOWING FOR ONLY
A SLIGHT CHANCE OF SHOWERS AND STORMS. OVERALL MOISTURE AND
INSTABILITY APPEAR LACKING SATURDAY INTO MONDAY AND WHILE PRECIP
POTENTIAL IS NOT ZERO IT LOOKS TO BE LESS THAN 20 PERCENT AT THIS
TIME. TEMPERATURES RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH THE
PERIOD.
BDL
&&
.AVIATION...
06Z UPDATE...REMAINS A CHALLENGING FORECAST WITH CIGS THE BIG
QUESTION AND UNCERTAINTY IS GREAT WITH THE GUIDANCE. WITH THE
AMOUNT OF RAIN MOST AREAS HAVE SEEN...LEANING TOWARD THE MORE
PESSIMISTIC PROJECTIONS OF IFR DEVELOPMENT AT THE TERMINALS
TONIGHT. VSBY SHOULD REMAIN MVFR AT ATL BUT AGAIN CONFIDENCE IS
LOW. BETTER CHANCE OF LOWER VSBY AND LIFR CONDITIONS AT AHN AND
MCN WHERE LOW LEVEL MOISTURE BECOMES MORE PREVALENT TOWARD
DAYBREAK. SHOULD SEE CIGS LIFT TO VFR BY LATE MORNING TO EARLY
AFTERNOON WITH DECK SCATTERING OUT BY MID AFTERNOON.
//ATL
CONFIDENCE...06Z UPDATE...
LOW ON CIGS.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 65 86 64 / 20 5 40 40
ATLANTA 85 68 86 67 / 20 5 30 30
BLAIRSVILLE 82 58 83 63 / 20 5 30 30
CARTERSVILLE 86 65 87 66 / 20 5 20 20
COLUMBUS 88 67 89 67 / 20 10 20 20
GAINESVILLE 83 65 85 66 / 20 5 40 40
MACON 86 64 88 64 / 30 5 30 30
ROME 87 65 88 66 / 20 5 20 20
PEACHTREE CITY 86 62 87 63 / 20 5 30 30
VIDALIA 85 66 87 69 / 40 20 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
148 AM EDT MON MAY 20 2013
.PREV DISCUSSION... /ISSUED 1114 PM EDT SUN MAY 19 2013/
UPDATE...CONVECTION HAS FINALLY PUSHED SOUTH OF THE AREA BRINGING
PRECIP TO AN END AS WELL AS THE THREAT FOR ANY ADDITIONAL STRONG
OR SEVERE STORMS. HOWEVER...FLOODING CONTINUES WITH AREAL FLOOD
AND RIVER WARNINGS REPLACING FLASH FLOOD WARNINGS FROM EARLIER.
THERE COULD BE SOME ADDITIONAL RIVERS TO GO INTO FLOOD BUT NOTHING
TO WARRANT CONTINUATION OF FLOOD WATCH AND HAVE LET IT EXPIRE.
UPDATE WILL INCLUDE TRIMMING POPS FURTHER BUT REMAINING ELEMENTS
LOOK ON TRACK.
DEESE
PREV DISCUSSION... /ISSUED 750 PM EDT SUN MAY 19 2013/
PREV DISCUSSION... /ISSUED 312 PM EDT SUN MAY 19 2013/
SHORT TERM /TONIGHT THROUGH MONDAY/...
A RATHER MESSY UPPER LEVEL SYSTEM CONTINUES TO KEEP THE RISK OF
THUNDERSTORMS WITH HEAVY RAIN OVER MUCH OF THE CWA LATE THIS
AFTERNOON. REDEVELOPMENT OF THUNDERSTORMS ACROSS EASTERN TN/NORTH
GA IS REINFORCING THE FORECAST BY THE HRRR WHICH BRINGS ANOTHER
ROUND OT THUNDERSTORMS DOWN THE WEST SIDE OF GA THROUGH 00Z. THIS
WILL ALSO KEEP THE RISK OF FLASH FLOODING OVER THE WATCH AREA
THROUGH 00Z. THE PRECIP WILL SLOWLY EXIT FROM THE WEST TONIGHT
ALTHOUGH SOUTHEAST/EAST GA WILL STILL SEE SCATTERED
SHOWERS/TSTORMS INTO MONDAY. BY MONDAY AFTERNOON HIGH PRESSURE
WILL BE BUILDING OVER AL/GA WHICH SHOULD ALSO STABILIZE THE
ATMOSPHERE ENDING THE PRECIP BY MONDAY NIGHT/TUESDAY. MAV/MET
TEMPS LOOKING ALRIGHT...PERHAPS ON THE COOL SIDE TONIGHT AND HAVE
RAISE THEM A DEGREE OR TWO. WITH MORE SUNSHINE MONDAY
AFTERNOON...EXPECT TEMPS TO RISE WELL INTO THE 80S MOST AREAS.
17
LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
VERY FEW CHANGES TO THE EXTENDED. MADE SOME ADJUSTMENTS TO TEMPS
ON SATURDAY TO ACCOUNT FOR DRY CAD PROGGED TO DEVELOP. 12Z RUNS OF
GFS AND ECMWF STILL SIMILAR FOR THE SYSTEM AT THE END OF THE WEEK WITH
VERY LITTLE PRECIP EXPECTED AND THE FRONT MOVING THROUGH SOMETIME
EARLY FRIDAY. ALSO INCREASED CLOUD COVER A LITTLE FOR THE
WEDNESDAY SYSTEM AND ADJUSTED TEMPS ACCORDINGLY THERE AS
WELL...OTHERWISE NO SIGNIFICANT CHANGES.
TDP
PREV DISCUSSION... /ISSUED 357 AM EDT SUN MAY 19 2013/
PRECIP SHOULD END FROM WEST TO EAST TONIGHT AS THE SHORTWAVE
TROUGH SETS UP ALONG THE EASTERN SEABOARD. HAVE ONLY TWEAKED POPS
DURING THIS PERIOD.
FOR THE FIRST PART OF THE WEEK...THE 500MB TROUGH/SHEAR AXIS REMAINS
ACROSS THE SE COAST. THIS FEATURE WILL HELP FOCUS SCT DIURNAL
CONVECTION EACH DAY. PREVIOUS RUNS PUSHED THE FEATURE OFF THE COAST
ON TUESDAY...BUT IT SHOULD REMAIN IN PLACE UNTIL EARLY WEDNESDAY.
FOR THE LATTER PART OF THE WEEK...A COLD FRONT IS EXPECTED TO MOVE
INTO THE SOUTHEAST STATES. MODEL RUN TO RUN CONSISTENCY FOR THIS
FEATURE HAS BEEN LOW FOR THE PAST FEW DAYS. THE ECMWF NOW HAS THE
BOUNDARY APPROACHING NORTHERN GA ON FRIDAY...AND MOVING THROUGH THE
CWFA DURING THE DAY. THE GFS HAS CONTINUES TO BRING THE BOUNDARY
SOUTHWARD. NEITHER MODEL IS PRODUCING MUCH PRECIP WITH THIS FEATURE
FOR NOW...SO WILL LEAVE POPS IN THE SCT RANGE.
HIGH PRESSURE RETURNS FOR NEXT WEEKEND.
MAIN CHANGES TO THE EXTENDED WERE TO UP POPS SLIGHTLY IN THE EAST
FOR WEDNESDAY. MAINLY PERSISTENCE FOR THE LATTER HALF OF WEEK.
NLISTEMAA
&&
.AVIATION...
06Z UPDATE... REMAINS A CHALLENGING FORECAST WITH CIGS THE BIG
QUESTION AND UNCERTAINTY IS GREAT WITH THE GUIDANCE. WITH THE
AMOUNT OF RAIN MOST AREAS HAVE SEEN...LEANING TOWARD THE MORE
PESSIMISTIC PROJECTIONS OF IFR DEVELOPMENT AT THE TERMINALS
TONIGHT. VSBY SHOULD REMAIN MVFR AT ATL BUT AGAIN CONFIDENCE IS
LOW. BETTER CHANCE OF LOWER VSBY AND LIFR CONDITIONS AT AHN AND
MCN WHERE LOW LEVEL MOISTURE BECOMES MORE PREVALENT TOWARD
DAYBREAK. SHOULD SEE CIGS LIFT TO VFR BY LATE MORNING TO EARLY
AFTERNOON WITH DECK SCATTERING OUT BY MID AFTERNOON.
//ATL
CONFIDENCE...06Z UPDATE...
LOW ON CIGS.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 86 65 86 67 / 10 10 30 20
ATLANTA 86 67 85 69 / 10 10 30 10
BLAIRSVILLE 83 60 82 64 / 10 10 40 20
CARTERSVILLE 87 65 87 67 / 10 10 20 20
COLUMBUS 89 67 89 71 / 10 10 10 10
GAINESVILLE 83 65 83 67 / 10 10 40 20
MACON 87 65 88 68 / 20 20 20 10
ROME 88 64 87 68 / 10 10 20 10
PEACHTREE CITY 86 65 86 66 / 10 10 20 10
VIDALIA 88 67 87 70 / 50 40 40 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
222 PM CDT MON MAY 20 2013
.DISCUSSION...
ISSUED 222 PM CDT MON MAY 20 2013
SEVERE WEATHER CHANCES CONTINUE TO BE THE MAIN FOCUS...WITH RAIN
CHANCES LINGERING THROUGH THURSDAY. A COOLING TREND WILL DEVELOP
MID WEEK WITH BELOW NORMAL TEMPS FOR LATE WEEK AND INTO THE
WEEKEND.
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT.
THE ATMOSPHERE STARTED OUT THE AFTERNOON A BIT MORE STABLE THAN
MODEL GUIDANCE HAD INDICATED. MUCAPE VALUES ARE IN AROUND 500 J/KG
WITH SOME CONVECTIVE INHIBITION OF 150-200 J/KG. SFC DEWPOINTS AND TEMPS
ARE ON THE RISE AND INCREASING MID LEVEL JET WINDS TO THE
SOUTHWEST SHOULD STILL TO NOSE INTO CENTRAL ILLINOIS BY EVENING.
THE ONSET OF SEVERE STORMS MAY BE SLIGHTLY DELAYED DUE TO THE TIME
IT WILL TAKE FOR THE INGREDIENTS FOR STORMS TO DEVELOP. THE
EVOLUTION SHOULD BE FOR DISCREET SUPERCELLS FORMING IN MISSOURI
AND ADVANCING EAST ALONG THE AXIS OF INSTABILITY FROM SW TO NE.
THE DIRECTIONAL SHEAR IN THE PLAINS WILL EVOLVE TO MORE
UNIDIRECTIONAL SHEAR ACROSS CENTRAL IL. THAT WILL HELP THE
SUPERCELLS TO EVOLVE INTO MORE OF A LINEAR SETUP, WITH STRAIGHT-
LINE AND DOWNBURST WINDS MORE LIKELY. EMBEDDED SUPERCELLS WILL
STILL BE POSSIBLE DUE TO AMBIENT VORTICITY NEAR PRE-EXISTING
CONVECTIVE BOUNDARIES ALL OVER CENTRAL ILLINOIS.
THE EVENING HOURS LOOK TO BE OUR PRIMARY SEVERE WINDOW...WITH A
DOWNWARD TREND IN SEVERE AFTER MIDNIGHT AS THE STORMS HEAD INTO
OUR EASTERN COUNTIES. THE 4KM HRRR IS DEPICTING THE NW HALF OF OUR
AREA TO HAVE THE BEST CHANCES FOR STORMS...WITH LINEAR STORM
SEGMENTS DEVELOPING AFTER MIDNIGHT IN THE SOUTHEAST HALF...AND A
MORE ISOLATED SEVERE THREAT BUT STILL PRESENT.
THE SEVERE POTENTIAL ON TUESDAY WILL BE TIED TO THE ADVANCEMENT OF
A 500 MB SHORTWAVE AND RESULTANT SURFACE CYCLOGENESIS FROM THE
SOUTHERN PLAINS ACROSS CENTRAL IL. THE PRIMARY FORCING FOR STORMS
LOOKS TO HOLD OFF UNTIL TUESDAY EVENING...WHEN THE WAVE WILL MOVES
INTO WESTERN IL. STORMS ARE EXPECTED TO ERUPT ACROSS EASTERN MO
AND SW IL IN THE EVENING AND PROGRESS TO THE E-NE OVERNIGHT. WE
SEVERE POTENTIAL SHOULD BE HIGHER SOUTHEAST OF I-55...BASED ON THE
TRACK OF THE SURFACE LOW AND LOCATION OF THE 850 MB LLJ.
STORMS SHOULD BE PRIMARY EAST OF OUR AREA BY SUNRISE
WEDNESDAY...BUT ADDITIONAL SHOWERS AND A FEW STORMS WILL BE
POSSIBLE AS COLD AIR ADVANCES INTO IL. VARIOUS SHORTWAVES WILL BE
ROTATING ACROSS ILLINOIS AS THE UPPER TROUGH AXIS MOVES INTO
WESTERN IL.
LONG TERM...THURSDAY THROUGH MONDAY.
ON THURSDAY...THE SLOW MOVEMENT OF THE UPPER LEVEL AND SURFACE
LOWS FROM THE NORTHERN PLAINS ACROSS THE GREAT LAKES WILL CAUSE
SHOWERS TO LINGER ACROSS CENTRAL IL. THE AXIS OF THE ELEVATED COLD
POOL ALOFT WILL PASS ACROSS IL AROUND MID-DAY THURSDAY. LAPSE
RATES APPEAR FAVORABLE FOR SOME INSTABILITY SHOWERS TO DEVELOP IN
THE HEAT OF THE DAY...WITH A LITTLE HELP FROM CHANNELED VORTICITY
IN THE LEE SIDE OF THE UPPER TROUGH.
CLEARING SKIES THURSDAY NIGHT WILL ALLOW LOWS TO DIP INTO THE
UPPER 40S NORTH OF A LINE FROM RUSHVILLE TO LINCOLN TO CHAMPAIGN.
DESPITE SUNSHINE ON FRIDAY...HIGH TEMPS WILL STRUGGLE TO REACH
AROUND 70 IN MOST OF THE AREA.
THE 00Z/20 ECMWF HAD A WET HOLIDAY WEEKEND FORECAST...WITH A DRY
FORECAST FROM THE 00Z/GFS. THEY APPEAR TO HAVE FLIP-FLOPPED THE
FORECAST WITH THE 12Z VERSIONS. THE 12Z GFS NOW SHOWING RAIN
CHANCES LATE SATURDAY THROUGH MEMORIAL DAY. THE ECMWF STILL HAS
SOME RAIN LATE FRI NIGHT INTO SATURDAY...BUT DRY CONDITIONS FOR
SUNDAY AND MEMORIAL DAY. THE ALLBLEND HAS BASICALLY KEPT SOME
MENTION OF RAIN DUE TO THE PRESENT SIGNAL FROM AT LEAST ONE MODEL
EACH DAY OF THE WEEKEND. THE MAIN THEME REMAINS THAT A WAVE OF
ENERGY IS FORECAST TO EXIT THE PLAINS EARLY IN THE WEEKEND BUT
WHERE THE FRONT STALLS OUT FOR LINGERING RAIN REMAINS TO BE SEEN.
SHIMON
&&
.AVIATION...
ISSUED 1246 PM CDT MON MAY 20 2013
CLUSTER OF THUNDERSTORMS CURRENTLY CROSSING THE MISSISSIPPI RIVER
JUST SOUTH OF QUINCY WILL TRACK E/NE INTO THE AREA EARLY THIS
AFTERNOON. AIRMASS IS BEGINNING TO DESTABILIZE IN ADVANCE OF THIS
CONVECTION...SO CONFIDENCE IS GROWING THAT IT WILL HOLD TOGETHER
AND ARRIVE AT KSPI BETWEEN 19Z AND 21Z. ITS EVOLUTION BEYOND THAT
STILL REMAINS IN QUESTION...SO WILL ONLY CARRY VCTS AFTER 21Z AT
THE REMAINING TERMINALS. OUTSIDE OF ANY CONVECTION THAT DEVELOPS
THIS AFTERNOON...STRONG SOUTHERLY WINDS WILL GUST TO BETWEEN 25
AND 30KT. MODELS DISAGREE ABOUT THE TIMING/PLACEMENT OF ADDITIONAL
CONVECTION LATER TODAY AND TONIGHT...HOWEVER THE HRRR CONTINUES TO
FOCUS THE MOST WIDESPREAD STORMS DURING THE EVENING INTO THE
OVERNIGHT HOURS. WILL THEREFORE KEEP TEMPO GROUPS FOR THUNDER
BETWEEN 02Z AND 06Z AT KPIA AND BETWEEN 04Z AND 08Z FURTHER EAST
AT KCMI. AFTER THAT...MID-LEVEL DRYING IN THE WAKE OF THE
OVERNIGHT CONVECTION WILL LEAD TO A DRY TUESDAY MORNING.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1246 PM CDT MON MAY 20 2013
.DISCUSSION...
ISSUED 1041 AM CDT MON MAY 20 2013
AIRMASS HAS TEMPORARILY STABILIZED ACROSS CENTRAL ILLINOIS THIS
MORNING...THANKS TO OVERNIGHT CONVECTION THAT HAS PUSHED THE MAIN
OUTFLOW BOUNDARY TO A LAFAYETTE INDIANA TO FLORA ILLINOIS LINE.
15Z/10AM LAPS DATA SHOWS SBCAPE VALUES OF LESS THAN 500J/KG
BEHIND THE BOUNDARY...WITH VALUES IN EXCESS OF 2000J/KG AHEAD OF
THE BOUNDARY ACROSS THE FAR SE KILX CWA. FORECAST SOUNDINGS SHOW
AIRMASS GRADUALLY DESTABILIZING BY THIS AFTERNOON...HOWEVER
HIGHEST DEWPOINTS AND SUBSEQUENT CAPE VALUES WILL BE FOCUSED
FURTHER SOUTHEAST OVER THE OHIO RIVER VALLEY. NEVERTHELESS...CAPES
OF 1500 TO 2500J/KG SHOULD BE REALIZED ACROSS MUCH OF THE AREA
LATER TODAY. IN ADDITION...STRONG LOW-LEVEL SHEAR WILL BE IN
PLACE ACROSS THE WESTERN HALF OF THE CWA...WITH 0-6KM BULK SHEAR
VALUES RANGING FROM 45 TO 55KT. COMBINATION OF MODEST INSTABILITY
AND STRONG SHEAR WILL BE ENOUGH TO SUPPORT THE DEVELOPMENT OF
STRONG TO SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO THE
EVENING. HIGH-RES MODELS SUCH AS THE NAM12 AND 4KM HRRR SUGGEST
CONVECTION WILL FIRE ALONG ANOTHER BOUNDARY STRETCHING FROM
EASTERN KANSAS INTO WEST-CENTRAL ILLINOIS AFTER 19Z/2PM. INITIAL
CONVECTIVE MODE WILL BE SUPPORTIVE OF SUPERCELLS THIS AFTERNOON/EARLY
EVENING...BEFORE STORMS BECOME MORE LINEAR BY MID EVENING AS THEY
TRACK FROM SW TO NE ACROSS THE AREA. HAVE MODIFIED POPS/TEMPS JUST
A BIT FOR THE REMAINDER OF THE DAY...BUT CHANGES DO NOT
SIGNIFICANTLY IMPACT GOING FORECAST. CHANCE SHOWERS/STORMS THIS
MORNING...WITH LIKELY POPS ARRIVING ALONG/WEST OF I-55 BY MID TO
LATE AFTERNOON.
&&
.AVIATION...
ISSUED 1246 PM CDT MON MAY 20 2013
CLUSTER OF THUNDERSTORMS CURRENTLY CROSSING THE MISSISSIPPI RIVER
JUST SOUTH OF QUINCY WILL TRACK E/NE INTO THE AREA EARLY THIS
AFTERNOON. AIRMASS IS BEGINNING TO DESTABILIZE IN ADVANCE OF THIS
CONVECTION...SO CONFIDENCE IS GROWING THAT IT WILL HOLD TOGETHER
AND ARRIVE AT KSPI BETWEEN 19Z AND 21Z. ITS EVOLUTION BEYOND THAT
STILL REMAINS IN QUESTION...SO WILL ONLY CARRY VCTS AFTER 21Z AT
THE REMAINING TERMINALS. OUTSIDE OF ANY CONVECTION THAT DEVELOPS
THIS AFTERNOON...STRONG SOUTHERLY WINDS WILL GUST TO BETWEEN 25
AND 30KT. MODELS DISAGREE ABOUT THE TIMING/PLACEMENT OF ADDITIONAL
CONVECTION LATER TODAY AND TONIGHT...HOWEVER THE HRRR CONTINUES TO
FOCUS THE MOST WIDESPREAD STORMS DURING THE EVENING INTO THE
OVERNIGHT HOURS. WILL THEREFORE KEEP TEMPO GROUPS FOR THUNDER
BETWEEN 02Z AND 06Z AT KPIA AND BETWEEN 04Z AND 08Z FURTHER EAST
AT KCMI. AFTER THAT...MID-LEVEL DRYING IN THE WAKE OF THE
OVERNIGHT CONVECTION WILL LEAD TO A DRY TUESDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT MON MAY 20 2013
SHORT TERM...TODAY THROUGH THURSDAY
UNSETTLED WEATHER PATTERN EXPECTED THROUGH MID WEEK AS LARGE UPPER
LEVEL LOW OVER NE/SD GRADUALLY WEAKENS AS IT MOVES EASTWARD INTO
THE GREAT LAKES. SPC CONTINUES A SLIGHT RISK OF SEVERE STORMS
ACROSS MUCH OF IL FROM THIS AFTERNOON INTO TUE NIGHT. MODELS HAVE
TRENDED A BIT FASTER WITH WX SYSTEM AND SPC RISK OF SEVERE STORMS
ON WED IS EAST OF IL.
LEADING EDGE OF SHOWERS AND A FEW THUNDERSTORMS AS FAR EAST AS
PEORIA AND JACKSONVILLE WHILE STRONG TO SEVERE STORMS HEADING
TOWARD ST LOUIS METRO AREA EARLY THIS MORNING. MORE NUMEROUS
THUNDERSTORMS WERE OVER CENTRAL AND SW MO INTO SE KS WITH MCS
COMPLEX. ANOTHER AREA OF CONVECTION WAS OVER NE WI WITH ANOTHER
WEAKENING MCS. SURFACE MAP SHOWS DEEPENING 998 MB LOW PRESSURE
OVER CENTRAL SD WITH ITS WARM FRONT OVER NORTHERN WI WHILE ITS
COLD FRONT WAS OVER EASTERN NEBRASKA INTO CENTRAL KS/OK. IL WAS IN
WARM SECTOR WITH MOIST DEWPOINTS IN THE 60S AND EVEN 70F AT OLNEY
AND FAIRFIELD IN SE IL. TEMPS AT 3 AM WERE IN THE LOWER TO MIDDLE
70S EXCEPT RAIN COOLED MID 60S OVER WEST CENTRAL IL.
559 DM 500 MB LOW TO SLOWLY MOVE EAST INTO EASTERN SD BY SUNSET
WITH 998 MB SURFACE LOW MOVING INTO WEST CENTRAL MN. ANOTHER ROUND
OF SEVERE STORMS EXPECTED TO FIRE UP DURING MID/LATE AFTERNOON AND
CONTINUE INTO TONIGHT OVER THE CENTRAL PLAINS AND BE FURTHER EAST
INTO IL LATE THIS AFTERNOON AND TONIGHT. VERY UNSTABLE AIR MASS
WITH CAPES OF 2500-3500 J/KG AND GOOD WIND SHEAR TO AID IN THE
DEVELOPMENT OF SEVERE STORMS INCLUDING SOME SUPERCELLS. SPC HAS
15% RISK OF LARGE HAIL AND DAMAGING WIND GUSTS OVER IL WITH 30%
RISK OF LARGE HAIL FROM I-55 WEST AND 30% RISK OF DAMAGING WINDS
GUSTS FROM I-57 WEST. ALSO HAVE AT LEAST A 5% RISK OF TORNADOS
OVER MUCH OF IL EXCEPT FAR SE IL. HIGHS THIS AFTERNOON AGAIN IN
THE UPPER 80S TO NEAR 90F WITH DEWPOINTS IN THE UPPER 60S AND
LOWER 70S SO WILL FEEL LIKE A MID SUMMER DAY IN JULY.
UPPER LEVEL LOW STAYS IN PLACE NEAR SE SD TUE AND THEN WEAKENS A
BIT TO 562 DM AS IT TRACKS EASTWARD INTO EASTERN IA BY SUNSET WED
WHILE SURFACE LOW MOVES INTO SOUTHERN LAKE MI. ANOTHER SLIGHT RISK
OF SEVERE STORMS OVER MUCH OF IL TUE AFTERNOON/EVENING THOUGH NOT
QUITE AS UNSTABLE AS THIS AFTERNOON...AND SYSTEM IS STARTING TO
WEAKEN SO COVERAGE OF SEVERE STORMS APPEARS LESS. SPC HAS AT LEAST
15% RISK OF DAMAGING WINDS AND LARGE HAIL WITH THE 30% RISK SW IL SW
OF CLAY COUNTY. HIGHS TUE IN THE LOW TO MID 80S. SHOWERS STILL
LIKELY WED WITH A FEW THUNDERSTORMS ESPECIALLY OVER EASTERN IL.
RAINFALL AMOUNTS OF 1 TO 2 INCHES POSSIBLE TODAY THROUGH WED.
WEAKENING UPPER LEVEL TROF MOVES INTO IL THU KEEPING A CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS ALONG WITH COOLER TEMPS WITH
HIGHS AROUND 70F FROM I-74 NORTH AND MID 70S IN SE IL.
LONG TERM...THURSDAY NIGHT THROUGH SUNDAY NIGHT
DRY WEATHER FINALLY RETURNS TO CENTRAL/SE IL THU NIGHT THROUGH FRI
NIGHT AS HIGHS PRESSURE SETTLES INTO THE GREAT LAKES REGIONS.
CARRIED 20-40% CHANCE OF SHOWERS AND THUNDERSTORMS FROM SAT
AFTERNOON THROUGH SUNDAY NIGHT OVER CENTRAL AND SE IL WITH SOME
MODELS SHOWING SHORT WAVE RIDGING OVER TOP OF UPPER LEVEL RIDGE INTO
PARTS OF IL THIS WEEKEND. THOUGH CONFIDENCE OF THIS HAPPENING IS LOW.
TEMPS SHOULD MODIFY EARLY NEXT WEEK WITH SOME UPPER LEVEL RIDGING
INTO IL.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1041 AM CDT MON MAY 20 2013
.DISCUSSION...
ISSUED 1041 AM CDT MON MAY 20 2013
AIRMASS HAS TEMPORARILY STABILIZED ACROSS CENTRAL ILLINOIS THIS
MORNING...THANKS TO OVERNIGHT CONVECTION THAT HAS PUSHED THE MAIN
OUTFLOW BOUNDARY TO A LAFAYETTE INDIANA TO FLORA ILLINOIS LINE.
15Z/10AM LAPS DATA SHOWS SBCAPE VALUES OF LESS THAN 500J/KG
BEHIND THE BOUNDARY...WITH VALUES IN EXCESS OF 2000J/KG AHEAD OF
THE BOUNDARY ACROSS THE FAR SE KILX CWA. FORECAST SOUNDINGS SHOW
AIRMASS GRADUALLY DESTABILIZING BY THIS AFTERNOON...HOWEVER
HIGHEST DEWPOINTS AND SUBSEQUENT CAPE VALUES WILL BE FOCUSED
FURTHER SOUTHEAST OVER THE OHIO RIVER VALLEY. NEVERTHELESS...CAPES
OF 1500 TO 2500J/KG SHOULD BE REALIZED ACROSS MUCH OF THE AREA
LATER TODAY. IN ADDITION...STRONG LOW-LEVEL SHEAR WILL BE IN
PLACE ACROSS THE WESTERN HALF OF THE CWA...WITH 0-6KM BULK SHEAR
VALUES RANGING FROM 45 TO 55KT. COMBINATION OF MODEST INSTABILITY
AND STRONG SHEAR WILL BE ENOUGH TO SUPPORT THE DEVELOPMENT OF
STRONG TO SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO THE
EVENING. HIGH-RES MODELS SUCH AS THE NAM12 AND 4KM HRRR SUGGEST
CONVECTION WILL FIRE ALONG ANOTHER BOUNDARY STRETCHING FROM
EASTERN KANSAS INTO WEST-CENTRAL ILLINOIS AFTER 19Z/2PM. INITIAL
CONVECTIVE MODE WILL BE SUPPORTIVE OF SUPERCELLS THIS AFTERNOON/EARLY
EVENING...BEFORE STORMS BECOME MORE LINEAR BY MID EVENING AS THEY
TRACK FROM SW TO NE ACROSS THE AREA. HAVE MODIFIED POPS/TEMPS JUST
A BIT FOR THE REMAINDER OF THE DAY...BUT CHANGES DO NOT
SIGNIFICANTLY IMPACT GOING FORECAST. CHANCE SHOWERS/STORMS THIS
MORNING...WITH LIKELY POPS ARRIVING ALONG/WEST OF I-55 BY MID TO
LATE AFTERNOON.
BARNES
&&
.AVIATION...
ISSUED 652 AM CDT MON MAY 20 2013
VFR CONDITIONS WILL CONTINUE AT ALL SITES THIS MORNING AND INTO
THIS EVENING. BASED ON RADAR TRENDS NARROW BAND OF RAIN IS NOT
MOVING EAST AND IS REMAINING JUST WEST OF SPI AND OVER PIA. SO NEW
TAFS FOR DEC/CMI/BMI WILL ALL BE DRY...WHILE PIA WILL HAVE -RA FOR
A FEW HOURS AND SPI WILL JUST BE VCTS TIL 15Z. BEYOND THIS...ALL
SITES WILL BE DRY UNTIL THE NEXT ROUND OF THUNDERSTORMS MOVES INTO
THE AREA. ROUGH GUESS IS STORMS WILL DEVELOP WEST OF THE AREA THIS
AFTERNOON AND THEN MOVE INTO THE STATE EARLY THIS EVENING. WILL
HAVE VCTS TO START AT ALL SITES AND THEN PICKED A 4HR BLOCK FOR A
TEMPO GROUP FOR WHEN THINKING BEST CHANCE OF THUNDERSTORMS
IS...THEN DRY COUPLE HOURS AFTER THAT. WINDS WILL BE SOUTHERLY
TO SOUTHWESTERLY THROUGH THE PERIOD...WITH STRONGEST WIND SPEEDS
BEING DURING THE DAY.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT MON MAY 20 2013
SHORT TERM...TODAY THROUGH THURSDAY
UNSETTLED WEATHER PATTERN EXPECTED THROUGH MID WEEK AS LARGE UPPER
LEVEL LOW OVER NE/SD GRADUALLY WEAKENS AS IT MOVES EASTWARD INTO
THE GREAT LAKES. SPC CONTINUES A SLIGHT RISK OF SEVERE STORMS
ACROSS MUCH OF IL FROM THIS AFTERNOON INTO TUE NIGHT. MODELS HAVE
TRENDED A BIT FASTER WITH WX SYSTEM AND SPC RISK OF SEVERE STORMS
ON WED IS EAST OF IL.
LEADING EDGE OF SHOWERS AND A FEW THUNDERSTORMS AS FAR EAST AS
PEORIA AND JACKSONVILLE WHILE STRONG TO SEVERE STORMS HEADING
TOWARD ST LOUIS METRO AREA EARLY THIS MORNING. MORE NUMEROUS
THUNDERSTORMS WERE OVER CENTRAL AND SW MO INTO SE KS WITH MCS
COMPLEX. ANOTHER AREA OF CONVECTION WAS OVER NE WI WITH ANOTHER
WEAKENING MCS. SURFACE MAP SHOWS DEEPENING 998 MB LOW PRESSURE
OVER CENTRAL SD WITH ITS WARM FRONT OVER NORTHERN WI WHILE ITS
COLD FRONT WAS OVER EASTERN NEBRASKA INTO CENTRAL KS/OK. IL WAS IN
WARM SECTOR WITH MOIST DEWPOINTS IN THE 60S AND EVEN 70F AT OLNEY
AND FAIRFIELD IN SE IL. TEMPS AT 3 AM WERE IN THE LOWER TO MIDDLE
70S EXCEPT RAIN COOLED MID 60S OVER WEST CENTRAL IL.
559 DM 500 MB LOW TO SLOWLY MOVE EAST INTO EASTERN SD BY SUNSET
WITH 998 MB SURFACE LOW MOVING INTO WEST CENTRAL MN. ANOTHER ROUND
OF SEVERE STORMS EXPECTED TO FIRE UP DURING MID/LATE AFTERNOON AND
CONTINUE INTO TONIGHT OVER THE CENTRAL PLAINS AND BE FURTHER EAST
INTO IL LATE THIS AFTERNOON AND TONIGHT. VERY UNSTABLE AIR MASS
WITH CAPES OF 2500-3500 J/KG AND GOOD WIND SHEAR TO AID IN THE
DEVELOPMENT OF SEVERE STORMS INCLUDING SOME SUPERCELLS. SPC HAS
15% RISK OF LARGE HAIL AND DAMAGING WIND GUSTS OVER IL WITH 30%
RISK OF LARGE HAIL FROM I-55 WEST AND 30% RISK OF DAMAGING WINDS
GUSTS FROM I-57 WEST. ALSO HAVE AT LEAST A 5% RISK OF TORNADOS
OVER MUCH OF IL EXCEPT FAR SE IL. HIGHS THIS AFTERNOON AGAIN IN
THE UPPER 80S TO NEAR 90F WITH DEWPOINTS IN THE UPPER 60S AND
LOWER 70S SO WILL FEEL LIKE A MID SUMMER DAY IN JULY.
UPPER LEVEL LOW STAYS IN PLACE NEAR SE SD TUE AND THEN WEAKENS A
BIT TO 562 DM AS IT TRACKS EASTWARD INTO EASTERN IA BY SUNSET WED
WHILE SURFACE LOW MOVES INTO SOUTHERN LAKE MI. ANOTHER SLIGHT RISK
OF SEVERE STORMS OVER MUCH OF IL TUE AFTERNOON/EVENING THOUGH NOT
QUITE AS UNSTABLE AS THIS AFTERNOON...AND SYSTEM IS STARTING TO
WEAKEN SO COVERAGE OF SEVERE STORMS APPEARS LESS. SPC HAS AT LEAST
15% RISK OF DAMAGING WINDS AND LARGE HAIL WITH THE 30% RISK SW IL SW
OF CLAY COUNTY. HIGHS TUE IN THE LOW TO MID 80S. SHOWERS STILL
LIKELY WED WITH A FEW THUNDERSTORMS ESPECIALLY OVER EASTERN IL.
RAINFALL AMOUNTS OF 1 TO 2 INCHES POSSIBLE TODAY THROUGH WED.
WEAKENING UPPER LEVEL TROF MOVES INTO IL THU KEEPING A CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS ALONG WITH COOLER TEMPS WITH
HIGHS AROUND 70F FROM I-74 NORTH AND MID 70S IN SE IL.
LONG TERM...THURSDAY NIGHT THROUGH SUNDAY NIGHT
DRY WEATHER FINALLY RETURNS TO CENTRAL/SE IL THU NIGHT THROUGH FRI
NIGHT AS HIGHS PRESSURE SETTLES INTO THE GREAT LAKES REGIONS.
CARRIED 20-40% CHANCE OF SHOWERS AND THUNDERSTORMS FROM SAT
AFTERNOON THROUGH SUNDAY NIGHT OVER CENTRAL AND SE IL WITH SOME
MODELS SHOWING SHORT WAVE RIDGING OVER TOP OF UPPER LEVEL RIDGE INTO
PARTS OF IL THIS WEEKEND. THOUGH CONFIDENCE OF THIS HAPPENING IS LOW.
TEMPS SHOULD MODIFY EARLY NEXT WEEK WITH SOME UPPER LEVEL RIDGING
INTO IL.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
534 PM EDT MON MAY 20 2013
.SYNOPSIS...
ISSUED AT 532 PM EDT MON MAY 20 2013
SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO INCREASE TONIGHT THROUGH
WEDNESDAY...WITH A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY.
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS EVENING
THROUGH TUESDAY NIGHT. DRIER AND COOLER WEATHER IS ANTICIPATED
LATE THIS WEEK INTO NEXT WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013
REMNANT GRAVITY WAVE FROM OVERNIGHT CONVECTION AND
ASSOCIATED WITH A ~10F DEGREE DEWPOINT DROP IN ITS WAKE HAS WASHED
OUT AS IT MOVED INTO OUR FORECAST AREA. THIS HAS KEPT MODERATELY
UNSTABLE AIRMASS ACROSS THE EASTERN TWO-THIRDS OF OUR FORECAST AREA.
ADDED SLIGHT CHANCE POPS FOR THE EAST THIS EVENING AS CONVECTION
COULD FIRE ALONG OR IN FRONT OF THIS BOUNDARY WHERE THE AIRMASS IS
CHARACTERIZED BY SBCAPE VALUES IN EXCESS OF 3000 J/KG. THE GREATEST
LIMITING FACTOR IS THE LACK OF SIGNIFICANT FORCING...ALTHOUGH
CONVECTION ACROSS MICHIGAN AND ADDITIONAL CONVECTION FIRING ALONG
THE BOUNDARY ACROSS EASTERN ILLINOIS AT 1830Z INDICATES THIS
BOUNDARY MAY PROVIDE JUST ENOUGH FORCED ASCENT FOR ISOLATED STORM
DEVELOPMENT.
STILL SOME UNCERTAINTY REGARDING CONVECTIVE EVOLUTION AND IMPACTS
ACROSS OUR AREA TONIGHT. DECAYING STORM CLUSTER ACROSS WESTERN
ILLINOIS SHOULD CONTINUE ITS WEAKENING TREND AS IT MOVES INTO A
MOISTURE VOID AREA ACROSS ILLINOIS WITH SURFACE DEWPOINTS IN THE
UPPER 50S. WITH THAT BEING SAID...SOME SHORT TERM MODEL GUIDANCE IS
INDICATING A QUICK RECOVERY OF THE MOISTURE PROFILE IN THAT AREA AS
850 MOISTURE TRANSPORT INCREASES THIS AFTERNOON. IF THE AIRMASS
AHEAD OF THESE STORMS CAN DESTABILIZE OVER THE NEXT FEW HOURS...AS
THE HRRR SUGGESTS...UPSCALE GROWTH OF THAT CLUSTER AS WELL AS
ADDITIONAL STORM DEVELOPMENT MAY TRACK ACROSS THE NORTHWEST PORTION
OF OUR FORECAST AREA DURING THE LATE EVENING. IF STORMS CAN
DEVELOP...SEVERE POTENTIAL DOES EXIST AS 0-6 KM SHEAR OF 35-45 KNOTS
OVERSPREADS THE NORTHWEST PORTION OF OUR FORECAST AREA WITH THE MAIN
THREATS BEING SEVERE HAIL AND WIND.
REMAIN MORE CONFIDENT IN PRECIPITATION CHANCES AFTER 06Z WHEN
REMNANT CONVECTION FROM MISSOURI TRACKS TOWARDS THE AREA. SEVERE
THREAT WILL BE MINIMAL WITH THIS CONVECTION DUE TO ITS TIMING DURING
THE EARLY MORNING HOURS.
TUESDAY LOOKS TO BE COOLER THAN TODAY AS LITTLE SUN WILL BE SEEN
ACROSS OUR FORECAST AREA DUE TO CLOUD DEBRIS FROM FROM OVERNIGHT
CONVECTION AS WELL AS ADDITIONAL DYNAMIC LIFT FROM 40-50 KT LLJ.
SEVERE THREAT DOES EXIST IF A FEW BREAKS IN THE CLOUDS CAN PROVIDE
SIGNIFICANT SURFACE HEATING FOR EVEN MARGINAL SURFACE BASED
INSTABILITY. THE MAIN THREAT WILL BE LARGE HAIL AND DAMAGING WINDS
AS UNIDIRECTIONAL 35-40 KNOT SHEAR OVERSPREADS THE AREA.
&&
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013
ONE OR TWO MORE ROUNDS OF CONVECTION TO BEGIN THE FORECAST PERIOD.
MODELS IN PRETTY GOOD AGREEMENT IN SHORT WAVE COMING OUT OF BASE OF
CLOSED LOW AND IMPACTING THE AREA TUE NIGHT. GOOD SUPPORT WILL
ACCOMPANY THIS FEATURE AND 50-60KT MID LEVEL SPEED MAX WILL COMBINE
WITH INFLUX OF LOW LEVEL MOISTURE WITH AT LEAST SUFFICIENT
INSTABILITY TO INITIATE OR MAINTAIN CONVECTION. UNIDIRECTIONAL WIND
PROFILE WITH AROUND 30KT OF SPEED SHEAR WILL HAVE DAMAGING WINDS AS
THE MAIN SEVERE THREAT. CLOSED LOW FINALLY OPENS UP AND WILL MOVE
EASTWARD INTO THE GREAT LAKES REGION WEDNESDAY NIGHT...BRINGING SFC
LOW AND MAIN COLD FRONT WITH IT. MODELS OFFERING VARYING
TIMING/PLACEMENT OF THESE FEATURES BUT ONE MORE ROUND OF CONVECTION
POSSIBLE WEDNESDAY...MAINLY FOR THE EASTERN HALF OF THE CWA. UPPER
TROF AXIS ROTATES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY
KEEPING CHANCE FOR A FEW SHOWERS BEFORE COOLER DRIER CANADIAN HIGH
PRESSURE BEGINS TO BUILD INTO THE GREAT LAKES REGION ON FRIDAY. THIS
WILL PROVIDE A NICE START TO THE HOLIDAY WEEKEND...QUESTIONS REMAIN
AS TO WHETHER IT WILL LAST THROUGH MONDAY. SFC RIDGE AXIS WILL
PROGRESS EASTWARD SUNDAY AND MONDAY...PLACING OUR AREA ON THE
WESTERN PERIPHERY OF THE HIGH WHILE MEDIUM RANGE MODELS ATTEMPTING
TO BRING SHORT WAVE ENERGY DOWN IN NW FLOW. GETTING BETTER MODEL
AGREEMENT WITH THIS SOLN BUT LOTS OF VARIATION IN TIMING AND
PLACEMENT. ENSEMBLE GUIDANCE NEAR OR MOSTLY BELOW CLIMO FOR POPS AS
WELL SO WILL STILL HOLD OUT FOR DRY FORECAST FOR AT LEAST ONE MORE
ISSUANCE. TEMPS TRENDING SEASONABLY COOLER WITH AOB NORMAL FOR MOST
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 20 2013
VFR CONDITIONS EXPECTED FOR THE REST OF TODAY AND INTO
THE OVERNIGHT HOURS. SLIGHT CHANCE THAT A STRAY SHOWER OR ISOLATED
STORM COULD POP UP NEAR KFWA...BUT CONFIDENCE WAS TOO LOW FOR
INCLUSION IN 18Z TAF ISSUANCE. STORMS WILL FIRE ACROSS MISSOURI
TODAY AND WILL LIKELY TRACK INTO NORTHERN INDIANA DURING THE EARLY
MORNING HOURS. THIS THREAT IS GREATEST AT KSBN. WILL WAIT FOR LATER
TAF ISSUANCES BEFORE INCLUDING THESE STORMS AS SUBTLE TIMING
DIFFERENCES AND EXACT LOCATION WILL NOT BE KNOWN UNTIL THE
CONVECTION HAS FIRED AND BEGINS TRACKING TOWARDS THE AREA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...STEINWEDEL/KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
307 PM EDT MON MAY 20 2013
.SYNOPSIS...
ISSUED AT 1052 AM EDT MON MAY 20 2013
A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS LATER TODAY THROUGH WEDNESDAY...WITH
A FEW SHOWERS POSSIBLY LINGERING INTO THURSDAY. THERE IS A SLIGHT
RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH TUESDAY
NIGHT. DRIER AND COOLER WEATHER IS ANTICIPATED LATE THIS WEEK
INTO NEXT WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013
REMNANT GRAVITY WAVE FROM OVERNIGHT CONVECTION AND
ASSOCIATED WITH A ~10F DEGREE DEWPOINT DROP IN ITS WAKE HAS WASHED
OUT AS IT MOVED INTO OUR FORECAST AREA. THIS HAS KEPT MODERATELY
UNSTABLE AIRMASS ACROSS THE EASTERN TWO-THIRDS OF OUR FORECAST AREA.
ADDED SLIGHT CHANCE POPS FOR THE EAST THIS EVENING AS CONVECTION
COULD FIRE ALONG OR IN FRONT OF THIS BOUNDARY WHERE THE AIRMASS IS
CHARACTERIZED BY SBCAPE VALUES IN EXCESS OF 3000 J/KG. THE GREATEST
LIMITING FACTOR IS THE LACK OF SIGNIFICANT FORCING...ALTHOUGH
CONVECTION ACROSS MICHIGAN AND ADDITIONAL CONVECTION FIRING ALONG
THE BOUNDARY ACROSS EASTERN ILLINOIS AT 1830Z INDICATES THIS
BOUNDARY MAY PROVIDE JUST ENOUGH FORCED ASCENT FOR ISOLATED STORM
DEVELOPMENT.
STILL SOME UNCERTAINTY REGARDING CONVECTIVE EVOLUTION AND IMPACTS
ACROSS OUR AREA TONIGHT. DECAYING STORM CLUSTER ACROSS WESTERN
ILLINOIS SHOULD CONTINUE ITS WEAKENING TREND AS IT MOVES INTO A
MOISTURE VOID AREA ACROSS ILLINOIS WITH SURFACE DEWPOINTS IN THE
UPPER 50S. WITH THAT BEING SAID...SOME SHORT TERM MODEL GUIDANCE IS
INDICATING A QUICK RECOVERY OF THE MOISTURE PROFILE IN THAT AREA AS
850 MOISTURE TRANSPORT INCREASES THIS AFTERNOON. IF THE AIRMASS
AHEAD OF THESE STORMS CAN DESTABILIZE OVER THE NEXT FEW HOURS...AS
THE HRRR SUGGESTS...UPSCALE GROWTH OF THAT CLUSTER AS WELL AS
ADDITIONAL STORM DEVELOPMENT MAY TRACK ACROSS THE NORTHWEST PORTION
OF OUR FORECAST AREA DURING THE LATE EVENING. IF STORMS CAN
DEVELOP...SEVERE POTENTIAL DOES EXIST AS 0-6 KM SHEAR OF 35-45 KNOTS
OVERSPREADS THE NORTHWEST PORTION OF OUR FORECAST AREA WITH THE MAIN
THREATS BEING SEVERE HAIL AND WIND.
REMAIN MORE CONFIDENT IN PRECIPITATION CHANCES AFTER 06Z WHEN
REMNANT CONVECTION FROM MISSOURI TRACKS TOWARDS THE AREA. SEVERE
THREAT WILL BE MINIMAL WITH THIS CONVECTION DUE TO ITS TIMING DURING
THE EARLY MORNING HOURS.
TUESDAY LOOKS TO BE COOLER THAN TODAY AS LITTLE SUN WILL BE SEEN
ACROSS OUR FORECAST AREA DUE TO CLOUD DEBRIS FROM FROM OVERNIGHT
CONVECTION AS WELL AS ADDITIONAL DYNAMIC LIFT FROM 40-50 KT LLJ.
SEVERE THREAT DOES EXIST IF A FEW BREAKS IN THE CLOUDS CAN PROVIDE
SIGNIFICANT SURFACE HEATING FOR EVEN MARGINAL SURFACE BASED
INSTABILITY. THE MAIN THREAT WILL BE LARGE HAIL AND DAMAGING WINDS
AS UNIDIRECTIONAL 35-40 KNOT SHEAR OVERSPREADS THE AREA.
&&
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM EDT MON MAY 20 2013
ONE OR TWO MORE ROUNDS OF CONVECTION TO BEGIN THE FORECAST PERIOD.
MODELS IN PRETTY GOOD AGREEMENT IN SHORT WAVE COMING OUT OF BASE OF
CLOSED LOW AND IMPACTING THE AREA TUE NIGHT. GOOD SUPPORT WILL
ACCOMPANY THIS FEATURE AND 50-60KT MID LEVEL SPEED MAX WILL COMBINE
WITH INFLUX OF LOW LEVEL MOISTURE WITH AT LEAST SUFFICIENT
INSTABILITY TO INITIATE OR MAINTAIN CONVECTION. UNIDIRECTIONAL WIND
PROFILE WITH AROUND 30KT OF SPEED SHEAR WILL HAVE DAMAGING WINDS AS
THE MAIN SEVERE THREAT. CLOSED LOW FINALLY OPENS UP AND WILL MOVE
EASTWARD INTO THE GREAT LAKES REGION WEDNESDAY NIGHT...BRINGING SFC
LOW AND MAIN COLD FRONT WITH IT. MODELS OFFERING VARYING
TIMING/PLACEMENT OF THESE FEATURES BUT ONE MORE ROUND OF CONVECTION
POSSIBLE WEDNESDAY...MAINLY FOR THE EASTERN HALF OF THE CWA. UPPER
TROF AXIS ROTATES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY
KEEPING CHANCE FOR A FEW SHOWERS BEFORE COOLER DRIER CANADIAN HIGH
PRESSURE BEGINS TO BUILD INTO THE GREAT LAKES REGION ON FRIDAY. THIS
WILL PROVIDE A NICE START TO THE HOLIDAY WEEKEND...QUESTIONS REMAIN
AS TO WHETHER IT WILL LAST THROUGH MONDAY. SFC RIDGE AXIS WILL
PROGRESS EASTWARD SUNDAY AND MONDAY...PLACING OUR AREA ON THE
WESTERN PERIPHERY OF THE HIGH WHILE MEDIUM RANGE MODELS ATTEMPTING
TO BRING SHORT WAVE ENERGY DOWN IN NW FLOW. GETTING BETTER MODEL
AGREEMENT WITH THIS SOLN BUT LOTS OF VARIATION IN TIMING AND
PLACEMENT. ENSEMBLE GUIDANCE NEAR OR MOSTLY BELOW CLIMO FOR POPS AS
WELL SO WILL STILL HOLD OUT FOR DRY FORECAST FOR AT LEAST ONE MORE
ISSUANCE. TEMPS TRENDING SEASONABLY COOLER WITH AOB NORMAL FOR MOST
OF THE FCST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 20 2013
VFR CONDITIONS EXPECTED FOR THE REST OF TODAY AND INTO
THE OVERNIGHT HOURS. SLIGHT CHANCE THAT A STRAY SHOWER OR ISOLATED
STORM COULD POP UP NEAR KFWA...BUT CONFIDENCE WAS TOO LOW FOR
INCLUSION IN 18Z TAF ISSUANCE. STORMS WILL FIRE ACROSS MISSOURI
TODAY AND WILL LIKELY TRACK INTO NORTHERN INDIANA DURING THE EARLY
MORNING HOURS. THIS THREAT IS GREATEST AT KSBN. WILL WAIT FOR LATER
TAF ISSUANCES BEFORE INCLUDING THESE STORMS AS SUBTLE TIMING
DIFFERENCES AND EXACT LOCATION WILL NOT BE KNOWN UNTIL THE
CONVECTION HAS FIRED AND BEGINS TRACKING TOWARDS THE AREA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...STEINWEDEL
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS TOPEKA KS
626 PM CDT TUE MAY 21 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 339 PM CDT TUE MAY 21 2013
UPPER LOW REMAINS ACROSS THE NORTHERN PLAINS WITH ENERGY ROTATING
AROUND THE BASE MOVING INTO NORTH CENTRAL NEBRASKA. A STRONG
SHORTWAVE WAS MOVING INTO WESTERN OKLAHOMA AT LATE AFTERNOON. MODELS
STILL SHOWING BEST FORCING (Q-VECTOR CONVERGENCE AND VORTICITY
ADVECTION) REMAINING TO THE SOUTH OF THE FORECAST AREA THIS EVENING.
SHORT RANGE HIGH RESOLUTION MODELS BREAK OUT SOME CONVECTION IN FAR
EAST CENTRAL KANSAS EARLY THIS EVENING AND WILL MAINTAIN SMALL
PRECIPITATION CHANCES FOR PARTS OF ANDERSON COUNTY THIS EVENING.
COLD ADVECTION ACROSS NORTHERN KANSAS WILL CONTINUE THROUGH THE
NIGHT WITH TEMPERATURES FALLING INTO THE UPPER 40S IN NORTH CENTRAL
KANSAS TO THE MID 50S IN EAST CENTRAL KANSAS.
CLOUDS WILL BE ON THE DECREASE WEDNESDAY MORNING AND EXPECT SOME
SCATTERED CUMULUS CLOUDS FOR MUCH OF THE AFTERNOON. COOL HIGH
PRESSURE WILL BUILD INTO NORTHEAST KANSAS WEDNESDAY AS THE UPPER
TROUGH MOVES INTO THE GREAT LAKES DURING THE DAY. TEMPERATURES WILL
BE COOLEST ACROSS THE FAR NORTH WITH HIGHS IN THE 60S WITH LOWER 70S
ACROSS THE SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 PM CDT TUE MAY 21 2013
WED NIGHT THROUGH THU NIGHT...THE UPPER TROUGH IN THE UPPER MS VALLEY
WILL SWING EASTWARD INTO THE GREAT LAKES AS THE HIGH PLAINS UPPER
RIDGE SHIFTS EASTWARD INTO THE EASTERN PLAINS. THIS WILL ALLOW FOR
THE DRY NORTH TO NORTHEASTERLY FLOW THROUGH 850MB TO PERSIST AND
KEEP ANY SIGNIFICANT MOISTURE AND/OR INSTABILITY TO THE SOUTH OF THE
COUNTY WARNING AREA UNTIL LATER THURSDAY NIGHT. THIS WHEN WEAK
THETA E/MOISTURE ADVECTION BEGINS ACROSS THE FAR WEST AND
SOUTHWESTERN PORTIONS OF THE CWA...SO WILL INTRODUCE A SLIGHT CHANCE
FOR THUNDERSTORMS AT THAT TIME. SEASONABLY COOL LOW TEMPERATURES IN
THE UPPER 40S AND LOWER 50S WEDNESDAY NIGHT WILL EDGE UP INTO THE LOW
TO MIDDLE 50S THURSDAY NIGHT WHILE HIGHS ON THURSDAY TOP OUT IN THE
LOW TO MIDDLE 70S.
FRI THROUGH TUESDAY...THE RIDGING ALOFT WILL SLOWLY TRANSLATE
EASTWARD INTO THE MO AND MS VALLEY AREAS OVER THE WEEKEND INTO EARLY
NEXT WEEK. THIS WILL TRANSITION THE FLOW ALOFT TO A MORE WEST AND
SOUTHWESTERLY DIRECTION. THIS WILL ALLOW FOR A LEE SIDE SFC
TROUGH/LOW IN THE CENTRAL HIGH PLAINS TO REMAIN ANCHORED THROUGH THE
PERIOD. AT THE SAME TIME...THE UPPER FLOW WILL LIKELY DIRECT A
SERIES OF WEAK SHORTWAVE TROUGHS OUT OF THE MAIN UPPER TROUGH IN THE
WESTERN CONUS OUT INTO THE CENTRAL PLAINS. MOISTURE RETURN WILL
CONTINUE/REMAIN IN PLACE THROUGH THE PERIOD...SO THE PASSAGE ANY OF
THE SHORTWAVE WILL HAVE THE POTENTIAL TO TRIGGER CONVECTION ACROSS
THE AREA THROUGH THE PERIOD. THIS FAR OUT IT REMAINS VERY DIFFICULT
TO PIN DOWN THE TIMING AND/OR AREAL EXTENT OF ANY CONVECTION AND
MESOSCALE FEATURES SUCH AS OUTFLOW BOUNDARIES FROM POSSIBLE MCS`S
EACH DAY WOULD ONLY COMPLICATE THE FCST. HAVE THEREFORE CONTINUED A
BROAD AND GENERAL FCST ON THE PRECIP POTENTIAL WITH HIGHS GENERALLY
IN THE 80S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 626 PM CDT TUE MAY 21 2013
MAIN CONCERN FOR THE TAFS IS WHETHER SOME MVFR CIGS BETWEEN 2 AND 3
KFT MOVE FAR ENOUGH SOUTH TO GET INTO THE TERMINALS. IF IT DOES IT
LOOKS LIKE IT WOULD BE DURING THE MID MORNING HOURS. CONFIDENCE IS
LOW WITH RAP AND NAM RH PROGS JUST CLIPPING THE TERMINALS WITH THE
HIGHER RH...SO HAVE KEPT A VFR FORECAST AT THIS TIME.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...53
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
353 PM CDT MON MAY 20 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 350 PM CDT MON MAY 20 2013
LATEST MESO ANALYSIS AT 19Z SHOWS A COUPLE OF FRONTS IN AND NEAR OUR
CWA. FIRST IS OFF TO THE WEST ACROSS CENTRAL KANSAS WITH THE OTHER
EXTENDING FROM NORTH CENTRAL OKLAHOMA INTO FAR SOUTHERN EAST CENTRAL
KANSAS SOUTH OF I-35. MOISTURE CONVERGENCE WAS NOTED ALONG BOTH OF
THE BOUNDARIES WITH THE STRONGEST ALONG THE SOUTHERN COUNTIES. BULK
SHEAR VALUES ARE STRONG ACROSS MUCH OF THE AREA WITH HIGHEST
INSTABILITY ACROSS SOUTHEAST KANSAS INTO EAST CENTRAL KANSAS.
0-1 KM STORM RELATIVE HELICITY AROUND 100 TO 120 M2/S2 ACROSS
SOUTHEAST AND EAST CENTRAL KANSAS. WINDS ARE BACKED SLIGHTLY IN THE
LOW LEVELS ALONG AND SOUTH OF I-35. ISOLATED TORNADO THREAT WILL
CONTINUE ALONG AND SOUTHEAST OF I-35 THROUGH MID EVENING.
HRRR AND RAP DEVELOP SCATTERED CONVECTION ACROSS NORTH CENTRAL AND
NORTHEAST KANSAS LATE THIS AFTERNOON AND EVENING. ALSO WATER VAPOR
SHOWS A MID LEVEL WAVE MOVING ACROSS SOUTHWEST KANSAS THIS WILL BE
COUPLED WITH ENERGY ROTATING AROUND THE NORTHERN PLAINS UPPER LOW
ACROSS NEBRASKA AND NORTH CENTRAL NEBRASKA THIS EVENING. WILL
CONTINUE WITH EVENING CHANCES OF THUNDERSTORMS ACROSS NORTH CENTRAL
AND NORTHEAST KANSAS. HIGHEST CHANCES WILL BE ALONG AND SOUTH OF
I-35. PRECIPITATION SHOULD MOVE OFF TO THE SOUTHEAST LATER TONIGHT
AS THE COOL FRONT MOVES EASTWARD. LOWS TONIGHT WILL BE IN THE 50S.
TUESDAY SHOULD BE RELATIVELY DRY ACROSS MUCH OF THE FORECAST AREA
SAVE THE FAR SOUTHEAST COUNTIES OF EAST CENTRAL KANSAS. BEST FORCING
WILL BE FOCUSED FURTHER SOUTH TUESDAY FROM OKLAHOMA INTO SOUTHERN
MISSOURI. HIGHS WILL BE IN THE MID 70S TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 350 PM CDT MON MAY 20 2013
LAST SHORTWAVE LOBE ON THE SOUTHERN PORTIONS OF THE UPPER LOW WILL
ROTATE SOUTHEAST OF THE COUNTY WARNING AREA TUESDAY NIGHT...SO
WILL CONTINUE WITH A DRY FCST TUESDAY NIGHT ON INTO THURSDAY AS
THE UPPER LOW SETTLES INTO THE EASTERN CONUS. BY THURSDAY NIGHT
INTO FRIDAY...INCREASING MOISTURE AND WARM AIR ADVECTION WILL TAKE
PLACE ON THE EASTERN SIDE OF BUILDING UPPER LEVEL RIDGE. WILL
INTRODUCE POPS AGAIN AT THAT TIME AND PERSIST THROUGH THE WEEKEND
AS WEAK SHORTWAVES MOVE THROUGH THE FLOW AND INTO THE RIDGE AXIS
NEAR THE COUNTY WARNING AREA. THIS WARRANTS KEEPING CONVECTIVE
POTENTIAL GOING THROUGH THE PERIOD...ALTHOUGH MODELS TRENDS ARE
HINTING THAT AN AMPLIFICATION OF THE UPPER RIDGE INTO EARLY NEXT
WEEK MAY FORCE THE STRONGER FLOW ALOFT AND HIGHER PRECIP CHANCES A
LITTLE FURTHER NORTH WITH IT. EITHER WAY...A GRADUAL WARMING TREND
STILL LOOKS ON TRACK AS WELL WITH HIGHS WARMING FROM MAINLY THE
70S WEDNESDAY INTO FRIDAY...THEN INTO THE LOW TO MIDDLE 80S FOR
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 350 PM CDT MON MAY 20 2013
VFR EXPECTED THROUGH THE PERIOD OUTSIDE OF CONVECTION LATE THIS
AFTERNOON AND EVENING. ADDED VCTS TO THE TERMINALS THIS AFTERNOON
FOR POSSIBLE CONVECTIVE DEVELOPMENT. EXPECT THE MAIN CONVECTION TO
REMAIN SOUTH OF THE TERMINALS. WINDS SOUTHWEST AROUND 10 KTS OR
LESS BECOMING MORE WESTERLY UNDER 10 KTS AFTER 04Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...53
LONG TERM...63
AVIATION...53
AREA FORECAST DISCUSSION
NWS JACKSON KY
106 PM EDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1223 PM EDT MON MAY 20 2013
WHILE A FEW MORE SHOWERS MAY CLIP THE EXTREME EASTERN END OF PIKE
COUNTY...THE MAIN BAND OF CONVECTION HAS FINALLY SHIFTED EAST. AM
STILL RELUCTANT TO REMOVE ALL CHANCES OF RAIN FOR THIS AFTERNOON AND
WILL LEAVE THE CURRENT LOW PROBABILITIES IN PLACE FOR THE EAST AND
CENTRAL AREAS. THE 14Z HRRR HAS TRENDED TOWARDS SOME ISOLATED
CONVECTION FOR THIS AFTERNOON. IT SHOULD ALSO BE NOTED THE HRRR WAS
MUCH TOO QUICK TO MOVE THE CONVECTIVE BAND OVER ERN KY AND WV EAST
THIS MORNING. HAVE UPDATED NDFD FOR LATEST TRENDS AND WILL UPDATE ZFP
SHORTLY.
UPDATE ISSUED AT 1036 AM EDT MON MAY 20 2013
PERSISTENT CONVECTION CONTINUES TO AFFECT FAR EASTERN PIKE COUNTY. IN
FACT CONVECTION CONTINUES TO DEVELOP UPSTREAM ALL THE WAY TO EAST OF
COLUMBUS OH. THE GOOD NEWS IS THAT THE BOUNDARY FOCUSING THIS
CONVECTION IS GRADUALLY SHIFTING EAST...AND WILL BE EAST OF PIKE
COUNTY BY EARLY AFTERNOON. THE RAINFALL RATES HAVE ALSO BEEN LESS THE
PAST COUPLE OF HOURS. FOR EXAMPLE THE PHELPS IFLOWS GAGE IS REPORTING
0.71 SINCE THE EVENT BEGAN...WITH 0.51 OF THIS FALLING BETWEEN 09Z
AND 10Z.
ONCE THE BAND OF CONVECTION IN THE FAR EAST MOVES OUT OF THE
STATE...THE 12Z HRRR AND 12Z NAM SHOW NO RAIN OVER OUR AREA FOR THE
REST OF THE DAY. HOWEVER HAVE ELECTED TO LEAVE THE LOW CHANCE
PROBABILITIES OF RAIN FOR THE EAST AND CENTRAL PART OF THE FORECAST
AREA. MORNING SOUNDINGS ARE QUITE UNSTABLE WITH LI OF -8 AT ILN AND -6
AT OHX. AM CONCERNED THAT BOUNDARIES LEFT FROM THIS MORNINGS
CONVECTION COULD FOCUS SOME ADDITIONAL CONVECTION LATER THIS
AFTERNOON.
HAVE UPDATED NDFD FOR LATEST HOURLY TRENDS BUT ZFP DOES NOT NEED AN
UPDATE AT THIS TIME.
UPDATE ISSUED AT 727 AM EDT MON MAY 20 2013
CONVECTION HAS BEEN PERSISTENT ACROSS FAR SOUTHEASTERN KENTUCKY EARLY
THIS MORNING. THE LATEST NAM AND SREF CONTINUE TO SHOW SOME ACTIVITY
LINGERING INTO THE MID-MORNING HOURS. AS SUCH...WILL ALLOW FOR HIGHER
POPS IN THE FAR EAST. THE FOG HAS ALSO BEEN MORE SPOTTY THIS
MORNING...SO WILL DOWNPLAY THIS INTO THE MID-MORNING HOURS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 351 AM EDT MON MAY 20 2013
A LEFTOVER OUTFLOW BOUNDARY MOVING THROUGH SOUTHEASTERN KENTUCKY HAS
SPARKED A BROKEN LINE OF SHOWERS AND THUNDERSTORMS...WITH EVEN A
STRAY SHOWER CURRENTLY AFFECTING THE JKL OFFICE. WILL INCLUDE SOME
ISOLATED POPS EARLY THIS MORNING GIVEN THESE TRENDS...ALTHOUGH THE
MAIN LINE LOOKS TO EXIT THE SOUTHEAST BETWEEN 4 AND 4:30 AM.
OTHERWISE...UPPER LEVEL RIDGING WILL BE BUILDING IN THROUGH THE DAY
TODAY ACROSS THE COMMONWEALTH IN RESPONSE TO A DEEP TROUGH SLOWLY
NUDGING EAST ACROSS THE PLAINS. THIS WILL RESULT IN MORE ISOLATED
CONVECTIVE COVERAGE. DESPITE A LACK OF DEEPER MOISTURE...THE LATEST
FORECAST SOUNDINGS SHOW QUITE A BIT OF INSTABILITY...SO ANYTHING THAT
DOES INITIATE COULD BE STRONG. WILL HIGHLIGHT THIS IN THE HWO. HIGHS
WILL TOP OUT IN THE MID 80S FOR MOST.
SKIES WILL CLEAR OUT TONIGHT...ALLOWING FOR SOME FOG ONCE AGAIN. LOWS
WILL BOTTOM OUT IN THE LOW TO MID 60S. ON TUESDAY...THE PLAINS TROUGH
WILL BE GETTING A LITTLE CLOSER AND ANY CAPPING WILL BE WEAK. WILL
ALLOW FOR SCATTERED CONVECTION DURING THE AFTERNOON HOURS...WITH SOME
OF THIS POSSIBLY BECOMING STRONG ONCE AGAIN...ESPECIALLY NEAR THE
BLUEGRASS COUNTIES. HIGHS WILL SOAR INTO THE UPPER 80S...THREATENING
RECORD HIGHS FOR THE DATE AT JKL AND LOZ.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 425 AM EDT MON MAY 20 2013
THE PERIOD SHOULD BEGIN RATHER ACTIVE AS AN UPPER LEVEL LOW INITIALLY
OVER THE PLAINS/MO VALLEY REGION AND A SHORTWAVE TROUGH EXTENDING TO
ITS SOUTH APPROACHES THE MS VALLEY AND LOWER OH VALLEY REGION TUE
NIGHT INTO EARLY ON WED. THE ASSOCIATED SFC LOW SHOULD DEEPEN A BIT
AS IT TRACKS TOWARD THE WESTERN GREAT LAKES REGION TUE NIGHT INTO
WED. A LOW LEVEL JET SHOULD TRANSPORT RATHER ABUNDANT MOISTURE INTO
THE REGION WITH PW FORECAST TO INCREASE TO AROUND 1.4 TO 1.5 INCHES.
THE UPPER LEVEL LOW WILL GRADUALLY OPEN UP WITH A SHORTWAVE TROUGH
WORKING ACROSS EASTERN KY LATER ON WED INTO WED NIGHT. MODELS BRING
SOME INCREASING WINDS ALOFT INTO THE AREA AT THAT POINT...THOUGH THE
STRONGER SHEAR SHOULD REMAIN TO OUR NORTH. THE UPPER LEVEL LOW SHOULD
WORK SLOWLY EAST SOUTHEAST REACHING THE UPPER OH VALLEY REGION AND
MID ATLANTIC STATES THU NIGHT INTO FRIDAY. AT THE SFC...THE LOW WILL
TRACK INTO THE EASTERN GREAT LAKES WED NIGHT AND THEN NORTHEAST
ACROSS THE ST LAWRENCE VALLEY WITH THE TRAILING COLD FRONT CROSSING
EASTERN KY ON THU.
THERE WILL PROBABLY BE A LULL IN CONVECTION FOR A TIME ON TUE NIGHT
BETWEEN RATHER DIURNALLY DRIVEN CONFECTION FROM TUE AND RESURGENCE
LIKELY TO OUR WEST AND SOUTHWEST WITH STRENGTHENING LOW LEVEL JET AND
APPROACHING UPPER LEVEL SHORTWAVE LATE TUE NIGHT. MODEL FORECAST
INSTABILITY AND SHEAR ALONG WITH TIMING OF MODELS BRINGING PREFRONTAL
CONVECTION INTO EASTERN KY POINT TOWARD THE POSSIBILITY OF STRONG TO
LOCALLY SEVERE STORMS POSSIBLE ANYWHERE IN THE CWA THOUGH THE NORTH
WILL BE CLOSER TO THE STRONGER LOW LEVEL JET CORE AS HIGHLIGHTED BY
SPC DAY 3 OUTLOOK. THE POTENTIAL FOR LOCALLY HEAVY RAIN AND SOME OF
THE STORMS TO BECOME STRONG WILL BE HIGHLIGHTED FOR WED IN THE HWO.
LIKELY POPS WERE USED FOR WED IN LINE WITH THE MODEL CONSENSUS AND
MOS GUIDANCE. THE MAV NUMBERS CONTINUE TO APPEAR TOO WARM UNLESS
THERE ENDS UP BEING LITTLE CLOUD COVER ON WED AND HIGH TEMPS WERE
TRENDED LOWER TOWARD MODEL CONSENSUS/MET GUIDANCE.
POPS WERE CONTINUED BEHIND THE BOUNDARY INTO FRI AS THE UPPER LEVEL
SYSTEM GRADUALLY WORKS ACROSS THE REGION. THE EXTENDED MODELS
APPEAR TO BE A IN A BIT BETTER AGREEMENT WITH THE UPPER LEVEL
LOW/SHORTWAVE TROUGH TO MOVE ACROSS THE AREA THU INTO FRI.
HOWEVER...LATER IN THE PERIOD THE GFS MAY BE SUFFERING FROM SOME
CONVECTIVE FEEDBACK ISSUES ACROSS THE PLAINS TO WESTERN GREAT LAKES
REGION SAT INTO SUN WHILE THE ECMWF CONTINUES TO DEVELOP CONVECTION
WITH DISTURBANCES IN NW FLOW INTERACTING WITH A WARM FRONT ADVANCING
TOWARD THE LOWER OH VALLEY REGION LATE IN THE PERIOD. THE EXTENDED
GRID LOAD MODEL CONSENSUS HAD SLIGHT CHANCE TO CHANCE POPS FOR SUN
AND THIS WAS GENERALLY FOLLOWED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 106 PM EDT MON MAY 20 2013
EXTENSIVE FIELD OF CU AND SC IS ACROSS THE AREA. SKY CONDITIONS ARE
QUITE VARIABLE RANGING FROM SCT TO OVC...WITH CEILINGS RANGING FROM
LESS THAN 3K FEET TO AROUND 5K FEET. CEILINGS WILL BE LIFTING
THROUGH THE REMAINDER OF THE AFTERNOON...WITH CLOUDS ALSO SCATTERING
OUT LATE. AS SUCH VFR CONDITIONS WILL PREVAIL INTO THE NIGHT. WITH UPPER
LEVEL HIGH PRESSURE BUILDING INTO THE AREA THUNDERSTORMS WILL BE MUCH
LESS LIKELY FOR THE REMAINDER OF THE DAY...ALTHOUGH AN ISOLATED
SHOWER OR THUNDERSTORM CANNOT BE RULED OUT IN THE CENTRAL AND EASTERN
PART OF THE FORECAST AREA. MVFR FOG CAN BE EXPECTED TOWARDS DAWN ON
TUESDAY...BUT THIS WILL BE VERY SHORT LIVED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GEOGERIAN
LONG TERM...JP
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1223 PM EDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1223 PM EDT MON MAY 20 2013
WHILE A FEW MORE SHOWERS MAY CLIP THE EXTREME EASTERN END OF PIKE
COUNTY...THE MAIN BAND OF CONVECTION HAS FINALLY SHIFTED EAST. AM
STILL RELUCTANT TO REMOVE ALL CHANCES OF RAIN FOR THIS AFTERNOON AND
WILL LEAVE THE CURRENT LOW PROBABILITIES IN PLACE FOR THE EAST AND
CENTRAL AREAS. THE 14Z HRRR HAS TRENDED TOWARDS SOME ISOLATED
CONVECTION FOR THIS AFTERNOON. IT SHOULD ALSO BE NOTED THE HRRR WAS
MUCH TOO QUICK TO MOVE THE CONVECTIVE BAND OVER ERN KY AND WV EAST
THIS MORNING. HAVE UPDATED NDFD FOR LATEST TRENDS AND WILL UPDATE ZFP
SHORTLY.
UPDATE ISSUED AT 1036 AM EDT MON MAY 20 2013
PERSISTENT CONVECTION CONTINUES TO AFFECT FAR EASTERN PIKE COUNTY. IN
FACT CONVECTION CONTINUES TO DEVELOP UPSTREAM ALL THE WAY TO EAST OF
COLUMBUS OH. THE GOOD NEWS IS THAT THE BOUNDARY FOCUSING THIS
CONVECTION IS GRADUALLY SHIFTING EAST...AND WILL BE EAST OF PIKE
COUNTY BY EARLY AFTERNOON. THE RAINFALL RATES HAVE ALSO BEEN LESS THE
PAST COUPLE OF HOURS. FOR EXAMPLE THE PHELPS IFLOWS GAGE IS REPORTING
0.71 SINCE THE EVENT BEGAN...WITH 0.51 OF THIS FALLING BETWEEN 09Z
AND 10Z.
ONCE THE BAND OF CONVECTION IN THE FAR EAST MOVES OUT OF THE
STATE...THE 12Z HRRR AND 12Z NAM SHOW NO RAIN OVER OUR AREA FOR THE
REST OF THE DAY. HOWEVER HAVE ELECTED TO LEAVE THE LOW CHANCE
PROBABILITIES OF RAIN FOR THE EAST AND CENTRAL PART OF THE FORECAST
AREA. MORNING SOUNDINGS ARE QUITE UNSTABLE WITH LI OF -8 AT ILN AND -6
AT OHX. AM CONCERNED THAT BOUNDARIES LEFT FROM THIS MORNINGS
CONVECTION COULD FOCUS SOME ADDITIONAL CONVECTION LATER THIS
AFTERNOON.
HAVE UPDATED NDFD FOR LATEST HOURLY TRENDS BUT ZFP DOES NOT NEED AN
UPDATE AT THIS TIME.
UPDATE ISSUED AT 727 AM EDT MON MAY 20 2013
CONVECTION HAS BEEN PERSISTENT ACROSS FAR SOUTHEASTERN KENTUCKY EARLY
THIS MORNING. THE LATEST NAM AND SREF CONTINUE TO SHOW SOME ACTIVITY
LINGERING INTO THE MID-MORNING HOURS. AS SUCH...WILL ALLOW FOR HIGHER
POPS IN THE FAR EAST. THE FOG HAS ALSO BEEN MORE SPOTTY THIS
MORNING...SO WILL DOWNPLAY THIS INTO THE MID-MORNING HOURS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 351 AM EDT MON MAY 20 2013
A LEFTOVER OUTFLOW BOUNDARY MOVING THROUGH SOUTHEASTERN KENTUCKY HAS
SPARKED A BROKEN LINE OF SHOWERS AND THUNDERSTORMS...WITH EVEN A
STRAY SHOWER CURRENTLY AFFECTING THE JKL OFFICE. WILL INCLUDE SOME
ISOLATED POPS EARLY THIS MORNING GIVEN THESE TRENDS...ALTHOUGH THE
MAIN LINE LOOKS TO EXIT THE SOUTHEAST BETWEEN 4 AND 4:30 AM.
OTHERWISE...UPPER LEVEL RIDGING WILL BE BUILDING IN THROUGH THE DAY
TODAY ACROSS THE COMMONWEALTH IN RESPONSE TO A DEEP TROUGH SLOWLY
NUDGING EAST ACROSS THE PLAINS. THIS WILL RESULT IN MORE ISOLATED
CONVECTIVE COVERAGE. DESPITE A LACK OF DEEPER MOISTURE...THE LATEST
FORECAST SOUNDINGS SHOW QUITE A BIT OF INSTABILITY...SO ANYTHING THAT
DOES INITIATE COULD BE STRONG. WILL HIGHLIGHT THIS IN THE HWO. HIGHS
WILL TOP OUT IN THE MID 80S FOR MOST.
SKIES WILL CLEAR OUT TONIGHT...ALLOWING FOR SOME FOG ONCE AGAIN. LOWS
WILL BOTTOM OUT IN THE LOW TO MID 60S. ON TUESDAY...THE PLAINS TROUGH
WILL BE GETTING A LITTLE CLOSER AND ANY CAPPING WILL BE WEAK. WILL
ALLOW FOR SCATTERED CONVECTION DURING THE AFTERNOON HOURS...WITH SOME
OF THIS POSSIBLY BECOMING STRONG ONCE AGAIN...ESPECIALLY NEAR THE
BLUEGRASS COUNTIES. HIGHS WILL SOAR INTO THE UPPER 80S...THREATENING
RECORD HIGHS FOR THE DATE AT JKL AND LOZ.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 425 AM EDT MON MAY 20 2013
THE PERIOD SHOULD BEGIN RATHER ACTIVE AS AN UPPER LEVEL LOW INITIALLY
OVER THE PLAINS/MO VALLEY REGION AND A SHORTWAVE TROUGH EXTENDING TO
ITS SOUTH APPROACHES THE MS VALLEY AND LOWER OH VALLEY REGION TUE
NIGHT INTO EARLY ON WED. THE ASSOCIATED SFC LOW SHOULD DEEPEN A BIT
AS IT TRACKS TOWARD THE WESTERN GREAT LAKES REGION TUE NIGHT INTO
WED. A LOW LEVEL JET SHOULD TRANSPORT RATHER ABUNDANT MOISTURE INTO
THE REGION WITH PW FORECAST TO INCREASE TO AROUND 1.4 TO 1.5 INCHES.
THE UPPER LEVEL LOW WILL GRADUALLY OPEN UP WITH A SHORTWAVE TROUGH
WORKING ACROSS EASTERN KY LATER ON WED INTO WED NIGHT. MODELS BRING
SOME INCREASING WINDS ALOFT INTO THE AREA AT THAT POINT...THOUGH THE
STRONGER SHEAR SHOULD REMAIN TO OUR NORTH. THE UPPER LEVEL LOW SHOULD
WORK SLOWLY EAST SOUTHEAST REACHING THE UPPER OH VALLEY REGION AND
MID ATLANTIC STATES THU NIGHT INTO FRIDAY. AT THE SFC...THE LOW WILL
TRACK INTO THE EASTERN GREAT LAKES WED NIGHT AND THEN NORTHEAST
ACROSS THE ST LAWRENCE VALLEY WITH THE TRAILING COLD FRONT CROSSING
EASTERN KY ON THU.
THERE WILL PROBABLY BE A LULL IN CONVECTION FOR A TIME ON TUE NIGHT
BETWEEN RATHER DIURNALLY DRIVEN CONFECTION FROM TUE AND RESURGENCE
LIKELY TO OUR WEST AND SOUTHWEST WITH STRENGTHENING LOW LEVEL JET AND
APPROACHING UPPER LEVEL SHORTWAVE LATE TUE NIGHT. MODEL FORECAST
INSTABILITY AND SHEAR ALONG WITH TIMING OF MODELS BRINGING PREFRONTAL
CONVECTION INTO EASTERN KY POINT TOWARD THE POSSIBILITY OF STRONG TO
LOCALLY SEVERE STORMS POSSIBLE ANYWHERE IN THE CWA THOUGH THE NORTH
WILL BE CLOSER TO THE STRONGER LOW LEVEL JET CORE AS HIGHLIGHTED BY
SPC DAY 3 OUTLOOK. THE POTENTIAL FOR LOCALLY HEAVY RAIN AND SOME OF
THE STORMS TO BECOME STRONG WILL BE HIGHLIGHTED FOR WED IN THE HWO.
LIKELY POPS WERE USED FOR WED IN LINE WITH THE MODEL CONSENSUS AND
MOS GUIDANCE. THE MAV NUMBERS CONTINUE TO APPEAR TOO WARM UNLESS
THERE ENDS UP BEING LITTLE CLOUD COVER ON WED AND HIGH TEMPS WERE
TRENDED LOWER TOWARD MODEL CONSENSUS/MET GUIDANCE.
POPS WERE CONTINUED BEHIND THE BOUNDARY INTO FRI AS THE UPPER LEVEL
SYSTEM GRADUALLY WORKS ACROSS THE REGION. THE EXTENDED MODELS
APPEAR TO BE A IN A BIT BETTER AGREEMENT WITH THE UPPER LEVEL
LOW/SHORTWAVE TROUGH TO MOVE ACROSS THE AREA THU INTO FRI.
HOWEVER...LATER IN THE PERIOD THE GFS MAY BE SUFFERING FROM SOME
CONVECTIVE FEEDBACK ISSUES ACROSS THE PLAINS TO WESTERN GREAT LAKES
REGION SAT INTO SUN WHILE THE ECMWF CONTINUES TO DEVELOP CONVECTION
WITH DISTURBANCES IN NW FLOW INTERACTING WITH A WARM FRONT ADVANCING
TOWARD THE LOWER OH VALLEY REGION LATE IN THE PERIOD. THE EXTENDED
GRID LOAD MODEL CONSENSUS HAD SLIGHT CHANCE TO CHANCE POPS FOR SUN
AND THIS WAS GENERALLY FOLLOWED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 727 AM EDT MON MAY 20 2013
PATCHY IFR OR WORSE FOG WILL MIX OUT OF THE DEEPER RIVER VALLEYS
THROUGH THE MID-MORNING HOURS. A FEW SHOWERS OR THUNDERSTORMS WILL
BE POSSIBLE DURING PEAK HEATING...HOWEVER THESE SHOULD BE ISOLATED
ENOUGH TO LEAVE OUT THE MENTION AT THE TAF SITES. MVFR FOG WILL
THREATEN LATE TONIGHT ONCE AGAIN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GEOGERIAN
LONG TERM...JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
1036 AM EDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1036 AM EDT MON MAY 20 2013
PERSISTENT CONVECTION CONTINUES TO AFFECT FAR EASTERN PIKE COUNTY. IN
FACT CONVECTION CONTINUES TO DEVELOP UPSTREAM ALL THE WAY TO EAST OF
COLUMBUS OH. THE GOOD NEWS IS THAT THE BOUNDARY FOCUSING THIS
CONVECTION IS GRADUALLY SHIFTING EAST...AND WILL BE EAST OF PIKE
COUNTY BY EARLY AFTERNOON. THE RAINFALL RATES HAVE ALSO BEEN LESS THE
PAST COUPLE OF HOURS. FOR EXAMPLE THE PHELPS IFLOWS GAGE IS REPORTING
0.71 SINCE THE EVENT BEGAN...WITH 0.51 OF THIS FALLING BETWEEN 09Z
AND 10Z.
ONCE THE BAND OF CONVECTION IN THE FAR EAST MOVES OUT OF THE
STATE...THE 12Z HRRR AND 12Z NAM SHOW NO RAIN OVER OUR AREA FOR THE
REST OF THE DAY. HOWEVER HAVE ELECTED TO LEAVE THE LOW CHANCE
PROBABILITIES OF RAIN FOR THE EAST AND CENTRAL PART OF THE FORECAST
AREA. MORNING SOUNDINGS ARE QUITE UNSTABLE WITH LI OF -8 AT ILN AND -6
AT OHX. AM CONCERNED THAT BOUNDARIES LEFT FROM THIS MORNINGS
CONVECTION COULD FOCUS SOME ADDITIONAL CONVECTION LATER THIS
AFTERNOON.
HAVE UPDATED NDFD FOR LATEST HOURLY TRENDS BUT ZFP DOES NOT NEED AN
UPDATE AT THIS TIME.
UPDATE ISSUED AT 727 AM EDT MON MAY 20 2013
CONVECTION HAS BEEN PERSISTENT ACROSS FAR SOUTHEASTERN KENTUCKY EARLY
THIS MORNING. THE LATEST NAM AND SREF CONTINUE TO SHOW SOME ACTIVITY
LINGERING INTO THE MID-MORNING HOURS. AS SUCH...WILL ALLOW FOR HIGHER
POPS IN THE FAR EAST. THE FOG HAS ALSO BEEN MORE SPOTTY THIS
MORNING...SO WILL DOWNPLAY THIS INTO THE MID-MORNING HOURS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 351 AM EDT MON MAY 20 2013
A LEFTOVER OUTFLOW BOUNDARY MOVING THROUGH SOUTHEASTERN KENTUCKY HAS
SPARKED A BROKEN LINE OF SHOWERS AND THUNDERSTORMS...WITH EVEN A
STRAY SHOWER CURRENTLY AFFECTING THE JKL OFFICE. WILL INCLUDE SOME
ISOLATED POPS EARLY THIS MORNING GIVEN THESE TRENDS...ALTHOUGH THE
MAIN LINE LOOKS TO EXIT THE SOUTHEAST BETWEEN 4 AND 4:30 AM.
OTHERWISE...UPPER LEVEL RIDGING WILL BE BUILDING IN THROUGH THE DAY
TODAY ACROSS THE COMMONWEALTH IN RESPONSE TO A DEEP TROUGH SLOWLY
NUDGING EAST ACROSS THE PLAINS. THIS WILL RESULT IN MORE ISOLATED
CONVECTIVE COVERAGE. DESPITE A LACK OF DEEPER MOISTURE...THE LATEST
FORECAST SOUNDINGS SHOW QUITE A BIT OF INSTABILITY...SO ANYTHING THAT
DOES INITIATE COULD BE STRONG. WILL HIGHLIGHT THIS IN THE HWO. HIGHS
WILL TOP OUT IN THE MID 80S FOR MOST.
SKIES WILL CLEAR OUT TONIGHT...ALLOWING FOR SOME FOG ONCE AGAIN. LOWS
WILL BOTTOM OUT IN THE LOW TO MID 60S. ON TUESDAY...THE PLAINS TROUGH
WILL BE GETTING A LITTLE CLOSER AND ANY CAPPING WILL BE WEAK. WILL
ALLOW FOR SCATTERED CONVECTION DURING THE AFTERNOON HOURS...WITH SOME
OF THIS POSSIBLY BECOMING STRONG ONCE AGAIN...ESPECIALLY NEAR THE
BLUEGRASS COUNTIES. HIGHS WILL SOAR INTO THE UPPER 80S...THREATENING
RECORD HIGHS FOR THE DATE AT JKL AND LOZ.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 425 AM EDT MON MAY 20 2013
THE PERIOD SHOULD BEGIN RATHER ACTIVE AS AN UPPER LEVEL LOW INITIALLY
OVER THE PLAINS/MO VALLEY REGION AND A SHORTWAVE TROUGH EXTENDING TO
ITS SOUTH APPROACHES THE MS VALLEY AND LOWER OH VALLEY REGION TUE
NIGHT INTO EARLY ON WED. THE ASSOCIATED SFC LOW SHOULD DEEPEN A BIT
AS IT TRACKS TOWARD THE WESTERN GREAT LAKES REGION TUE NIGHT INTO
WED. A LOW LEVEL JET SHOULD TRANSPORT RATHER ABUNDANT MOISTURE INTO
THE REGION WITH PW FORECAST TO INCREASE TO AROUND 1.4 TO 1.5 INCHES.
THE UPPER LEVEL LOW WILL GRADUALLY OPEN UP WITH A SHORTWAVE TROUGH
WORKING ACROSS EASTERN KY LATER ON WED INTO WED NIGHT. MODELS BRING
SOME INCREASING WINDS ALOFT INTO THE AREA AT THAT POINT...THOUGH THE
STRONGER SHEAR SHOULD REMAIN TO OUR NORTH. THE UPPER LEVEL LOW SHOULD
WORK SLOWLY EAST SOUTHEAST REACHING THE UPPER OH VALLEY REGION AND
MID ATLANTIC STATES THU NIGHT INTO FRIDAY. AT THE SFC...THE LOW WILL
TRACK INTO THE EASTERN GREAT LAKES WED NIGHT AND THEN NORTHEAST
ACROSS THE ST LAWRENCE VALLEY WITH THE TRAILING COLD FRONT CROSSING
EASTERN KY ON THU.
THERE WILL PROBABLY BE A LULL IN CONVECTION FOR A TIME ON TUE NIGHT
BETWEEN RATHER DIURNALLY DRIVEN CONFECTION FROM TUE AND RESURGENCE
LIKELY TO OUR WEST AND SOUTHWEST WITH STRENGTHENING LOW LEVEL JET AND
APPROACHING UPPER LEVEL SHORTWAVE LATE TUE NIGHT. MODEL FORECAST
INSTABILITY AND SHEAR ALONG WITH TIMING OF MODELS BRINGING PREFRONTAL
CONVECTION INTO EASTERN KY POINT TOWARD THE POSSIBILITY OF STRONG TO
LOCALLY SEVERE STORMS POSSIBLE ANYWHERE IN THE CWA THOUGH THE NORTH
WILL BE CLOSER TO THE STRONGER LOW LEVEL JET CORE AS HIGHLIGHTED BY
SPC DAY 3 OUTLOOK. THE POTENTIAL FOR LOCALLY HEAVY RAIN AND SOME OF
THE STORMS TO BECOME STRONG WILL BE HIGHLIGHTED FOR WED IN THE HWO.
LIKELY POPS WERE USED FOR WED IN LINE WITH THE MODEL CONSENSUS AND
MOS GUIDANCE. THE MAV NUMBERS CONTINUE TO APPEAR TOO WARM UNLESS
THERE ENDS UP BEING LITTLE CLOUD COVER ON WED AND HIGH TEMPS WERE
TRENDED LOWER TOWARD MODEL CONSENSUS/MET GUIDANCE.
POPS WERE CONTINUED BEHIND THE BOUNDARY INTO FRI AS THE UPPER LEVEL
SYSTEM GRADUALLY WORKS ACROSS THE REGION. THE EXTENDED MODELS
APPEAR TO BE A IN A BIT BETTER AGREEMENT WITH THE UPPER LEVEL
LOW/SHORTWAVE TROUGH TO MOVE ACROSS THE AREA THU INTO FRI.
HOWEVER...LATER IN THE PERIOD THE GFS MAY BE SUFFERING FROM SOME
CONVECTIVE FEEDBACK ISSUES ACROSS THE PLAINS TO WESTERN GREAT LAKES
REGION SAT INTO SUN WHILE THE ECMWF CONTINUES TO DEVELOP CONVECTION
WITH DISTURBANCES IN NW FLOW INTERACTING WITH A WARM FRONT ADVANCING
TOWARD THE LOWER OH VALLEY REGION LATE IN THE PERIOD. THE EXTENDED
GRID LOAD MODEL CONSENSUS HAD SLIGHT CHANCE TO CHANCE POPS FOR SUN
AND THIS WAS GENERALLY FOLLOWED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 727 AM EDT MON MAY 20 2013
PATCHY IFR OR WORSE FOG WILL MIX OUT OF THE DEEPER RIVER VALLEYS
THROUGH THE MID-MORNING HOURS. A FEW SHOWERS OR THUNDERSTORMS WILL
BE POSSIBLE DURING PEAK HEATING...HOWEVER THESE SHOULD BE ISOLATED
ENOUGH TO LEAVE OUT THE MENTION AT THE TAF SITES. MVFR FOG WILL
THREATEN LATE TONIGHT ONCE AGAIN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...GEOGERIAN
LONG TERM...JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
146 AM EDT MON MAY 20 2013
.UPDATE...
ISSUED AT 146 AM EDT MON MAY 20 2013
MADE A FEW TWEAKS TO THE LOW TEMPERATURES BASED ON THE LATEST TRENDS
IN OBSERVATIONS...OTHERWISE THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 1029 PM EDT SUN MAY 19 2013
SHOWER ACTIVITY DISSIPATED ABOUT 2 HOURS AGO WITH NO MORE ACTIVITY
EXPECTED TONIGHT DESPITE THE HI RES MODELS TRYING TO SHOW MORE
DEVELOPMENT OVERNIGHT. NO REAL TRIGGERS WITH HIGH PRESSURE BUILDING
IN...SO NO REASON TO GO WITH ANY POPS OVERNIGHT. SKIES ARE BEGINNING
TO CLEAR OFF...AND I IMAGINE SOME FOG IS ALREADY DEVELOPING IN THE
VALLEYS. LOCALLY DENSE FOG IS EXPECTED GIVEN THE CLEARING SKIES.
FORECAST IS HANDLED WELL...SO NO UPDATE PLANNED RIGHT NOW.
UPDATE ISSUED AT 740 PM EDT SUN MAY 19 2013
THINGS HAVE QUIETED DOWN FOR MUCH OF THE AREA. HOWEVER...VERY
UNSTABLE AIRMASS CONTINUES TO HOLD ITS GROUND ALONG AND NORTH OF
I-64...WITH MANY LOCATIONS STILL AROUND 80 DEGREES AT THE MOMENT.
UPDATED EARLIER TO INCLUDE A MENTION OF HAIL AND WINDS AS WE HAVE
SEEN SOME PRETTY GOOD STORMS ACROSS CENTRAL KENTUCKY AND CAN`T RULE
OUT SOME STRONG STORMS ACROSS THE NORTHERN PORTION OF THE AREA
OVER THE NEXT FEW HOURS. AFTER SUNSET...STUFF SHOULD REALLY DROP
OFF...WITH A QUIET NIGHT ANTICIPATED. STILL SOME QUESTION AS TO HOW
EXTENSIVE THE FOG WILL BE TONIGHT. WITH DEWPOINTS RUNNING WELL ABOVE
THEIR READINGS FROM YESTERDAY AT THIS TIME...IF WE CAN CLEAR OUT
TONIGHT...THE POTENTIAL FOR DENSE FOG WOULD CERTAINLY INCREASE. WILL
CONTINUE TO EVALUATE THE NEED FOR ANY STATEMENTS FOR ADVISORIES OVER
THE NEXT FEW HOURS TO SEE HOW THE CLOUDS EVOLVE OR DISSIPATE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 310 PM EDT SUN MAY 19 2013
MID/UPPER LOW OVER NORTHEAST KY WILL CONTINUE TO PULL AWAY WITH UPPER
RIDGING BUILDING INTO THE AREA FOR MONDAY. AN UPPER LEVEL LOCAL SPEED
MAXIMUM ON THE SOUTHERN SIDE OF THE LOW HAS HELPED SUPPORT THE
DEVELOPMENT OF NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHERN PART OF THE FORECAST AREA TODAY. SPEED MAX IS FORECAST TO WEAKEN
AND MOVE AWAY FROM THE AREA. THIS COMBINED WITH LOSS OF DAYTIME
HEATING SHOULD RESULT IN A QUICK DECREASE IN CONVECTION THIS EVENING.
THIS IS SUPPORTED BY THE 12Z NAM AND LATEST HRRR. THE HRRR DOES HAVE
SOME CONVECTION LINGERING TO AT LEAST MIDNIGHT...AND WILL KEEP A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE SOUTHEAST THROUGH
THIS TIME. FOG WILL DEVELOP AGAIN TONIGHT...WITH LOCALLY DENSE FOG
ESPECIALLY IN AREAS WHERE RAIN FELL TODAY.
WITH UPPER RIDGING OVER THE AREA ON MONDAY EXPECT CONVECTION TO BE
LESS ORGANIZED...EVEN THOUGH LOW LEVEL LAPSE RATES AND SURFACE BASED
INSTABILITY WILL BE GREATER THAN TODAY. WHILE THERE WILL NOT BE ANY
UPPER FORCING LIKE TODAY THERE WILL BE NUMEROUS BOUNDARIES LEFT FROM
TODAYS CONVECTION...SO WILL GO WITH SLIGHT CHANCE TO CHANCE
PROBABILITIES OVER ALL BUT THE FAR WESTERN TIER OF COUNTIES FOR
MONDAY. EXPECT ANY CONVECTION ON MONDAY TO AGAIN QUICKLY DISSIPATE
DURING THE EVENING.
WITH SHORT RANGE SOIL MOISTURE AND DROUGHT INDICES
SHOWING WETTER THAN NORMAL CONDITIONS IN THE FORECAST AREA WILL
CONTINUE TO DISREGARD THE GFS MOS HIGH TEMPERATURES OF 90 DEGREES FOR
MONDAY. WILL GO MOSTLY WITH MIDDLE 80S. RECORD HIGHS FOR MONDAY ARE
85 IN 1987 AT JKL AND 88 IN 1962 AT LOZ. WILL ALSO LEAN TOWARDS THE
NAM MOS PROBABILITY OF RAIN CHANCE GUIDANCE WHICH KEEPS LOW CHANCES
FOR TONIGHT AND MONDAY NIGHT...WITH BEST CHANCE FOR MONDAY. THIS IS
THE COMPLETE OPPOSITE OF THE GFS MOS GUIDANCE WHICH PLACES LOW
PROBABILITIES ON MONDAY WITH THE BEST CHANCES TONIGHT AND MONDAY
NIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 310 PM EDT SUN MAY 19 2013
THE EXTENDED FORECAST BEGINS WITH A RIDGE OVER THE EAST COAST AND A
SERIES OF MID LEVEL DISTURBANCES PRESSING EAST ALONG THE NRN CONUS
BORDER. A WAVE IN THE ERN PLAINS HAS SOUTHERLY FLOW AT THE SFC
WHICH WILL BRING GULF MOISTURE INTO ERN KY. SCATTERED TO NUMEROUS
SHOWERS AND A FEW THUNDERSTORMS WILL OCCUR WITHOUT MUCH ORGANIZATION
AS THE SFC LOW TAKES FORM AND MOVES INTO THE WRN GREAT LAKES. BY WED
THE COLD FRONT WILL MOVE INTO WRN KY AS THE MID LEVEL OPENS INTO A
WAVE AS IT PUSHES OVER THE ERN RIDGE. WED NIGHT WILL SEE A SERIES OF
WAVES CYCLE AROUND THE SRN EDGE OF THE 50H DISTURBANCE WITH
SCATTERED AREAS OF PCPN REFLECTED AT THE SFC. BY EARLY FRI MORNING
THE UPPER PATTERN HAS CHANGED TO A PLAINS RIDGE AND COASTAL TROFS.
SFC HIGH PRESSURE WILL DROP FROM THE NRN PLAINS AND BRING A PERIOD
OF DRY WEATHER. THAT WILL LAST THRU THE WEEKEND AS THE SFC HIGH
DRIFTS TOWARD THE EAST COAST WITH THE UPPER PATTERN BECOMING MORE
PROGRESSIVE.
FOR SENSIBLE WEATHER THE SOUTHERLY FLOW FROM THE GULF ON TUE WILL
BRING SCATTERED PCPN ALONG WITH TEMPS INTO THE MID 80S. THIS PATTERN
WILL CONTINUE THRU WED WITH OVERNIGHT LOWS RESTRICTED TO THE MID 60S
DUE TO HIGH DWPTS AND CLOUDS. THEN ON THU THE FIRST COLD FRONT WILL
CROSS ERN KY WITH SCATTERED STORMS AND COOLER TEMPS AS HIGHS ONLY
REACH THE UPPER 70S AND LOWS THU NIGHT DROP TO AROUND 60. WITH THE
SECOND SURGE OF COLD AIR FOLLOWING ON FRI LOOK FOR HIGHS IN THE MID
70S AND CLEARING LATE FRI WILL ALLOW OVERNIGHT LOWS TO DROP TO THE
MID 50S. THE COOL AIR WILL KEEP SAT HIGHS IN THE LOWER 70S IN SPITE
OF A REDUCTION IN CLOUDS EARLY AS THE DAYTIME MIXING WILL HELP
INCREASE CLOUD COVER TO COMPLEMENT THE COOLER NORTH WINDS. AS THE
DRIER AIR MOVES INTO ERN KY ON SUN THE WINDS WILL DIMINISH WITH THE
HIGH PRESSURE CROSSING TO OUR NORTH AND THE SUN WILL BEGIN THE
HEATING TO PUSH HIGHS BACK INTO THE MID 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 146 AM EDT MON MAY 20 2013
FOG WILL AGAIN BE A CONCERN OVERNIGHT...WITH BETTER PRECIPITATION
COVERAGE FROM YESTERDAY AFTERNOON. HAVE HIT THE FOG MORE SO AT JKL
AND LOZ SINCE BOTH LOCATIONS SAW DECENT RAINFALL. THERE IS SOME
LINGERING CU...SO CONDITIONS MAY NOT DETERIORATE UNTIL THE 09 TO 12Z
RANGE. ONCE THE FOG BURNS OFF...A RETURN TO VFR IS EXPECTED TO HOLD
THROUGH THE REST OF THE PERIOD. A FEW SHOWERS OR THUNDERSTORMS WILL
BE POSSIBLE DURING PEAK HEATING...HOWEVER THESE SHOULD BE ISOLATED
ENOUGH TO LEAVE OUT THE MENTION AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SBH
LONG TERM...DUSTY
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1147 PM EDT TUE MAY 21 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 315 PM EDT TUE MAY 21 2013
AN AREA OF LOW PRESSURE WILL DEVELOP OVER SOUTHEAST MISSOURI THIS
EVENING AND MOVE THROUGH CENTRAL MICHIGAN ON WEDNESDAY. THE
DEVELOPING LOW CENTER WILL BRING SOAKING RAINS AND A FEW STRONG
THUNDERSTORMS TO THE AREA LATE TONIGHT AND WEDNESDAY. MUCH COOLER
AIR AND SHOWERS WILL WRAP IN FROM THE NORTHWEST AS THE LOW DEPARTS
ON THURSDAY. CANADIAN HIGH PRESSURE WILL BUILD OVER THE REGION
THURSDAY NIGHT AND PROVIDE COOL AND DRY WEATHER THROUGH THE HOLIDAY
WEEKEND. THERE WILL ALSO BE A GOOD CHANCE OF A SCATTERED FROST ON
BOTH FRIDAY AND SATURDAY MORNING.
&&
.UPDATE...
ISSUED AT 1034 PM EDT TUE MAY 21 2013
LOWERED POPS SLIGHTLY FOR TONIGHT AS THE POSITION OF THE UPPER JET
CONTINUES TO FAVOR AREAS TO OUR SOUTH. THIS JET AND THE VORT PIVOTING
AROUND THE UPPER LOW WILL MOVE IN ON WED WHEN THE BULK OF THE PCPN
IS EXPECTED.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT TUE MAY 21 2013
THREATS ARE THREE FOLD NEXT FEW DAYS WITH ISOLATED STRONG/SEVERE
STORMS THIS EVENING...HEAVY RAIN AND POSSIBLE LOCAL FLOOD POTENTIAL
ON WEDNESDAY... AND THEN MUCH COOLER AIR WITH A LATE SEASON FROST
THREAT BOTH FRI AND SAT MORNING...
LIKE RECENT HRRR GUIDANCE INDICATING ISOL TO SCATTERED TSTORM
COVERAGE SOUTH AND EAST OF KBEH...KY70...KMOP LINE THIS EVENING.
OVERALL COVERAGE AND POTENTIAL FOR ORGANIZATION WILL BE SUPPRESSED
BY MODEST SHORTWAVE RIDGING AND UPPER CONVERGENCE. INITIAL FOCUS IS
AN AXIS OF 1000 J/KG MUCAPE STRETCHING FROM KGRR TOWARDS THE THUMB.
THAT COMBINED WITH 35KTS BULK 0-6KM SHEAR WILL LIKELY GIVE RISE TO
SOME STRONG AND POSSIBLY SEVERE PULSE TYPE STORMS.
HEAVY RAIN THREAT ON WEDNESDAY WITH SFC CYCLOGENESIS AND MID LEVEL
FRONTOGENESIS AS NICE SHORTWAVE MOVES NORTHEASTWARD FROM MO/AR THIS
EVENING CROSSING THE REGION WED. BOTH ECMWF AND GFS AS WELL AS SOME
OF THE SHORTER TERM MESO GUIDANCE ALL INDICATE A 75 WIDE 1-2 INCH
BAND OF RAIN ORIENTED SSW TO NNE ON WEDNESDAY. THE MOISTURE AND
DYNAMICS ARE CERTAINLY IN POSITION TO SUPPORT THE RAINFALL...IT IS
JUST WHERE THE AXIS OF THE HEAVIER RAINFALL WILL BE. AT THIS POINT
FEEL THE BEST BET WOULD BE JUST ABOUT ON A KAZO...KGRR...KMOP LINE
WITH KMKG ABOUT AS FAR WEST AS IT MIGHT BE AND KLAN AS FAR EAST.
WRAP AROUND MOISTURE AND MUCH COOLER AIR MOVE IN BY THURSDAY AS
UPPER LOW OVER MN OPENS AND SWINGS EASTWARD THROUGH THE REGION. H85
TEMPS DROP TO NEAR ZERO BY THU EVENING WITH MUCH DRIER SFC DEWPOINT
DRIVING INTO THE REGION AS UPSTREAM CANADIAN SFC HIGH BUILD
OVERHEAD. FEEL PRETTY CONFIDENT ABOUT FROST POTENTIAL FRI AND SAT
MORNING...ESPECIALLY UP NORTH AND IN SHELTERED LOW LYING AREAS
EVERYWHERE. NOT SURE WHICH MORNING WILL BE THE COLDER...FRI HAS THE
COLDER OVERALL AIRMASS BUT BOUNDARY LAYER WINDS WILL INHIBIT
RADIATIONAL COOLING.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 315 PM EDT TUE MAY 21 2013
THE LONG TERM PORTION OF THE FCST PERIOD LOOKS RATHER QUIET FOR
LOWER MICHIGAN. THE UPPER AIR PATTERN WILL TAKE ON SOME OF THE
CHARACTERISTICS OF AN OMEGA BLOCK. THIS OCCURS AS THE TROUGH/LOW
MOVING THROUGH MID WEEK HELPS TO ESTABLISH AN UPPER LOW ACROSS THE
NE U.S. AND THE CANADIAN MARITIMES. AN UPPER LOW WILL BECOME
ESTABLISHED ACROSS THE WRN U.S. COAST...WITH A RIDGE HOLDING ON IN
THE CENTRAL PORTION OF THE COUNTRY.
LOWER MICHIGAN SHOULD END UP UNDER THE DRY PORTION DOWNSTREAM OF THE
RIDGE AS IT SITS ALMOST STATIONARY. COOL NW FLOW ALOFT WILL KEEP
HIGHS IN THE 60S FROM FRI AND LIKELY THROUGH SUN WITH H850 TEMPS
ROUGHLY FROM 3-5C. WE STILL ARE EXPECTING SOME FROST POTENTIAL UP
NORTH ON FRI NIGHT BEFORE THE AIR MASS MODERATES SOME FOR THE
REMAINDER OF THE WEEKEND.
A WEAK SHORT WAVE WILL PUSH THROUGH THE REGION LATE SUN AND SUN
NIGHT. RIGHT NOW IT SEEMS THAT THIS SHOULD MOVE THROUGH DRY AS THE
LONG WAVE RIDGE SHOULD OVERCOME THIS WEAK SHORT WAVE. ALSO THE AIR
MASS SHOULD BE FAIRLY DRY WITH THE RIDGE SITTING OVER THE AREA FOR A
FEW DAYS AND NO GOOD MOISTURE ADVECTION EXPECTED THROUGH SUN.
SOME SPORADIC MODEL RUNS HAD BEEN SHOWING A WARM FRONT APPROACHING
LATE SUN AND REMAINING THROUGH TUE. THIS WOULD HAVE BROUGHT SOME
RAIN CHCS TO THE AREA. IT APPEARS NOW THAT THE NW FLOW ALOFT SHOULD
KEEP THIS FRONT SW OF THE AREA UNTIL AT LEAST TUE BEFORE SOME LOW
CHCS OF SHOWERS/STORMS WOULD DEVELOP. TEMPS WILL WARM INTO THE 70S
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1147 PM EDT TUE MAY 21 2013
SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE IN FROM THE
SOUTHWEST OVERNIGHT...WITH MVFR CONDITIONS DEVELOPING BY 12Z
WEDNESDAY IN MORE WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS. SOME
ISOLATED IFR IS POSSIBLE IN SOME OF THE HEAVIER RAIN BANDS OR
THUNDERSTORMS. WINDS WILL BE FROM THE SOUTHWEST AOB 10 KNOTS.
&&
.MARINE...
ISSUED AT 315 PM EDT TUE MAY 21 2013
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED ON THURSDAY AS COLDER AIR
WRAPS IN BEHIND DEPARTING LOW PRESSURE SYSTEM. HIGH PRESSURE WILL
BRING QUIET AND COOL CONDITIONS FOR MOST IF NOT ALL OF THE HOLIDAY
WEEKEND.
&&
.FIRE WEATHER...
ISSUED AT 315 PM EDT TUE MAY 21 2013
THE AREA WILL SEE PERIODS OF RAIN THROUGH THURSDAY. OVER AN INCH OF
RAIN IS LIKELY KEEPING THE FIRE RISK LOW.
&&
.HYDROLOGY...
ISSUED AT 315 PM EDT TUE MAY 21 2013
PERIODS OF HEAVIER RAIN IS EXPECTED BY LATE TONIGHT AND SHOULD
LINGER UNTIL THURSDAY. SOME TYPICAL LOCALIZED FLOODING IS POSSIBLE
BY WEDNESDAY AFTERNOON IN LOW LYING URBAN AND RURAL AREAS AND ON
SMALL STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JK
SYNOPSIS...DKC
SHORT TERM...DKC
LONG TERM...NJJ
AVIATION...OSTUNO
FIRE WEATHER...DKC
HYDROLOGY...DKC
MARINE...DKC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1034 PM EDT TUE MAY 21 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 315 PM EDT TUE MAY 21 2013
AN AREA OF LOW PRESSURE WILL DEVELOP OVER SOUTHEAST MISSOURI THIS
EVENING AND MOVE THROUGH CENTRAL MICHIGAN ON WEDNESDAY. THE
DEVELOPING LOW CENTER WILL BRING SOAKING RAINS AND A FEW STRONG
THUNDERSTORMS TO THE AREA LATE TONIGHT AND WEDNESDAY. MUCH COOLER
AIR AND SHOWERS WILL WRAP IN FROM THE NORTHWEST AS THE LOW DEPARTS
ON THURSDAY. CANADIAN HIGH PRESSURE WILL BUILD OVER THE REGION
THURSDAY NIGHT AND PROVIDE COOL AND DRY WEATHER THROUGH THE HOLIDAY
WEEKEND. THERE WILL ALSO BE A GOOD CHANCE OF A SCATTERED FROST ON
BOTH FRIDAY AND SATURDAY MORNING.
&&
.UPDATE...
ISSUED AT 1034 PM EDT TUE MAY 21 2013
LOWERED POPS SLIGHTLY FOR TONIGHT AS THE POSITION OF THE UPPER JET
CONTINUES TO FAVOR AREAS TO OUR SOUTH. THIS JET AND THE VORT PIVOTING
AROUND THE UPPER LOW WILL MOVE IN ON WED WHEN THE BULK OF THE PCPN
IS EXPECTED.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT TUE MAY 21 2013
THREATS ARE THREE FOLD NEXT FEW DAYS WITH ISOLATED STRONG/SEVERE
STORMS THIS EVENING...HEAVY RAIN AND POSSIBLE LOCAL FLOOD POTENTIAL
ON WEDNESDAY... AND THEN MUCH COOLER AIR WITH A LATE SEASON FROST
THREAT BOTH FRI AND SAT MORNING...
LIKE RECENT HRRR GUIDANCE INDICATING ISOL TO SCATTERED TSTORM
COVERAGE SOUTH AND EAST OF KBEH...KY70...KMOP LINE THIS EVENING.
OVERALL COVERAGE AND POTENTIAL FOR ORGANIZATION WILL BE SUPPRESSED
BY MODEST SHORTWAVE RIDGING AND UPPER CONVERGENCE. INITIAL FOCUS IS
AN AXIS OF 1000 J/KG MUCAPE STRETCHING FROM KGRR TOWARDS THE THUMB.
THAT COMBINED WITH 35KTS BULK 0-6KM SHEAR WILL LIKELY GIVE RISE TO
SOME STRONG AND POSSIBLY SEVERE PULSE TYPE STORMS.
HEAVY RAIN THREAT ON WEDNESDAY WITH SFC CYCLOGENESIS AND MID LEVEL
FRONTOGENESIS AS NICE SHORTWAVE MOVES NORTHEASTWARD FROM MO/AR THIS
EVENING CROSSING THE REGION WED. BOTH ECMWF AND GFS AS WELL AS SOME
OF THE SHORTER TERM MESO GUIDANCE ALL INDICATE A 75 WIDE 1-2 INCH
BAND OF RAIN ORIENTED SSW TO NNE ON WEDNESDAY. THE MOISTURE AND
DYNAMICS ARE CERTAINLY IN POSITION TO SUPPORT THE RAINFALL...IT IS
JUST WHERE THE AXIS OF THE HEAVIER RAINFALL WILL BE. AT THIS POINT
FEEL THE BEST BET WOULD BE JUST ABOUT ON A KAZO...KGRR...KMOP LINE
WITH KMKG ABOUT AS FAR WEST AS IT MIGHT BE AND KLAN AS FAR EAST.
WRAP AROUND MOISTURE AND MUCH COOLER AIR MOVE IN BY THURSDAY AS
UPPER LOW OVER MN OPENS AND SWINGS EASTWARD THROUGH THE REGION. H85
TEMPS DROP TO NEAR ZERO BY THU EVENING WITH MUCH DRIER SFC DEWPOINT
DRIVING INTO THE REGION AS UPSTREAM CANADIAN SFC HIGH BUILD
OVERHEAD. FEEL PRETTY CONFIDENT ABOUT FROST POTENTIAL FRI AND SAT
MORNING...ESPECIALLY UP NORTH AND IN SHELTERED LOW LYING AREAS
EVERYWHERE. NOT SURE WHICH MORNING WILL BE THE COLDER...FRI HAS THE
COLDER OVERALL AIRMASS BUT BOUNDARY LAYER WINDS WILL INHIBIT
RADIATIONAL COOLING.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 315 PM EDT TUE MAY 21 2013
THE LONG TERM PORTION OF THE FCST PERIOD LOOKS RATHER QUIET FOR
LOWER MICHIGAN. THE UPPER AIR PATTERN WILL TAKE ON SOME OF THE
CHARACTERISTICS OF AN OMEGA BLOCK. THIS OCCURS AS THE TROUGH/LOW
MOVING THROUGH MID WEEK HELPS TO ESTABLISH AN UPPER LOW ACROSS THE
NE U.S. AND THE CANADIAN MARITIMES. AN UPPER LOW WILL BECOME
ESTABLISHED ACROSS THE WRN U.S. COAST...WITH A RIDGE HOLDING ON IN
THE CENTRAL PORTION OF THE COUNTRY.
LOWER MICHIGAN SHOULD END UP UNDER THE DRY PORTION DOWNSTREAM OF THE
RIDGE AS IT SITS ALMOST STATIONARY. COOL NW FLOW ALOFT WILL KEEP
HIGHS IN THE 60S FROM FRI AND LIKELY THROUGH SUN WITH H850 TEMPS
ROUGHLY FROM 3-5C. WE STILL ARE EXPECTING SOME FROST POTENTIAL UP
NORTH ON FRI NIGHT BEFORE THE AIR MASS MODERATES SOME FOR THE
REMAINDER OF THE WEEKEND.
A WEAK SHORT WAVE WILL PUSH THROUGH THE REGION LATE SUN AND SUN
NIGHT. RIGHT NOW IT SEEMS THAT THIS SHOULD MOVE THROUGH DRY AS THE
LONG WAVE RIDGE SHOULD OVERCOME THIS WEAK SHORT WAVE. ALSO THE AIR
MASS SHOULD BE FAIRLY DRY WITH THE RIDGE SITTING OVER THE AREA FOR A
FEW DAYS AND NO GOOD MOISTURE ADVECTION EXPECTED THROUGH SUN.
SOME SPORADIC MODEL RUNS HAD BEEN SHOWING A WARM FRONT APPROACHING
LATE SUN AND REMAINING THROUGH TUE. THIS WOULD HAVE BROUGHT SOME
RAIN CHCS TO THE AREA. IT APPEARS NOW THAT THE NW FLOW ALOFT SHOULD
KEEP THIS FRONT SW OF THE AREA UNTIL AT LEAST TUE BEFORE SOME LOW
CHCS OF SHOWERS/STORMS WOULD DEVELOP. TEMPS WILL WARM INTO THE 70S
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 737 PM EDT TUE MAY 21 2013
EXPECT VFR CONDITIONS THIS EVENING...THERE COULD BE SOME ISOLATED
SHOWERS AND THUNDERSTORMS FROM AZO TO JXN HOWEVER. THEN MVFR
CONDITIONS DEVELOP BY 12Z WEDNESDAY AS SHOWERS AND A FEW
THUNDERSTORMS MOVE IN. WINDS WILL BE FROM THE SOUTHWEST AOB 10
KNOTS.
&&
.MARINE...
ISSUED AT 315 PM EDT TUE MAY 21 2013
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED ON THURSDAY AS COLDER AIR
WRAPS IN BEHIND DEPARTING LOW PRESSURE SYSTEM. HIGH PRESSURE WILL
BRING QUIET AND COOL CONDITIONS FOR MOST IF NOT ALL OF THE HOLIDAY
WEEKEND.
&&
.FIRE WEATHER...
ISSUED AT 315 PM EDT TUE MAY 21 2013
THE AREA WILL SEE PERIODS OF RAIN THROUGH THURSDAY. OVER AN INCH OF
RAIN IS LIKELY KEEPING THE FIRE RISK LOW.
&&
.HYDROLOGY...
ISSUED AT 315 PM EDT TUE MAY 21 2013
PERIODS OF HEAVIER RAIN IS EXPECTED BY LATE TONIGHT AND SHOULD
LINGER UNTIL THURSDAY. SOME TYPICAL LOCALIZED FLOODING IS POSSIBLE
BY WEDNESDAY AFTERNOON IN LOW LYING URBAN AND RURAL AREAS AND ON
SMALL STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JK
SYNOPSIS...DKC
SHORT TERM...DKC
LONG TERM...NJJ
AVIATION...OSTUNO
FIRE WEATHER...DKC
HYDROLOGY...DKC
MARINE...DKC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 PM EDT TUE MAY 21 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013
12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOW MOVING UPR LO
OVER ERN SDAKOTA BTWN UPR RDG OVER SCENTRAL CANADA AND A RIDGE OFF
THE SE CONUS. BAND OF SHRA/SCT TS THAT IMPACTED THE CWA EARLIER HAS
LIFTED TO THE N ALONG WITH RESPONSIBLE SHRTWV...ALLOWING FOR MAINLY
DRY WX OVER UPR MI EARLY THIS AFTN. BUT SINCE THE CWA IS N OF SFC
WARM FNT IN WI...PLENTY OF LO CLDS LINGER. THERE IS ALSO SOME FOG...
MAINLY NEAR THE COOLER GREAT LKS. ANOTHER DISTURBANCE IS ROTATING N
THRU IOWA ARND THE CLOSED LO. THE APRCH OF THIS DISTURBANCE HAS
RESULTED IN SOME SHRA OVER CENTRAL WI WHERE BREAKS IN THE LO CLDS
ALONG AND S OF WARM FNT HAVE LIFTED SB CAPE 500-1000 J/KG PER SPC
MESOANALYSIS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS TRENDS ASSOCIATED
WITH SHRTWV IN IOWA AND THEN APRCH OF MAIN UPR LO.
LATE THIS AFTN/TNGT...SHORT RANGE MODELS ARE IN FAIRLY GOOD
AGREEMENT SHOWING SHRA NOW OVER CENTRAL WI DRIFTING ACRS THE WI
BORDER BY 21Z AND THEN CONTINUING TO THE NE. RUC FCST SDNGS MODIFIED
FOR TEMP/DEWPT OF 68/58 YIELDS SBCAPE UP TO 750 J/KG...SO ADDED
MENTION OF TS. RELATIVELY WEAK WINDS SFC-H5 AS WELL AS DEEP
MSTR/SKINNY CAPE WITH PERSISTENT LO CLDS LIMITING DIURNAL HEATING
INDICATE A LO RISK FOR ANY SVR TS...BUT ANY SHRA COULD RESULT IN
SOME HEAVY RA WITH FCST KINX AS HI AS THE UPR 30S. ONCE THE SHRA
MOVE FARTHER TO THE NE AND AWAY FM THE SFC HEATING AREA...ONE MIGHT
EXPECT THESE SHRA TO DIMINISH THRU THE NGT. BUT FCST AREA OF H85-7
FGEN N OF WARM FNT MIGHT ACT TO SUSTAIN THESE SHRA. WL GO WITH HI
CHC-LIKELY POPS THIS EVNG NEAR THE WI BORDER DIMINISHING TO CHCY
POPS TO THE NE. SINCE THE LLVL FLOW IS FCST TO BACK MORE TO THE NE
FOLLOWING THE PASSAGE OF THIS SHRA AREA...EXPECT COOLER LAKE
AIR/SOME FOG TO MOVE BACK INTO THE AREA OVERNGT.
WED...AS CLOSED LO TO THE W BEGINS TO SHIFT FASTER TO THE ESE TO SW
WI BY 00Z THU...AREA OF LARGER SCALE QVECTOR CNVGC WL IMPACT MAINLY
THE AREA NEAR THE WI BORDER BUT WEAKEN WITH TIME AS THE UPR CLO
BEGINS TO OPEN. BAND OF RA ACCOMPANYING AXIS OF SHARPER FGEN OVER
WRN LK SUP/THE WRN ZNS SHOULD THUS SHIFT SLOWLY TO THE SE THRU THE
DAY. ARRIVAL OF DRIER AIR FM THE NW TO THE SE OF EXPANDING HI PRES
OVER SCENTRAL CANADA MIGHT START TO DIMINISH THE PCPN OVER THE FAR W
LATER IN THE DAY. OTRW...LOWERED FCST HI TEMPS TO ACCOUNT FOR STEADY
NE WIND OFF LK SUP AND EXPECTED CLD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013
AFTER A WET START TO THE WEEK...THE LONG TERM PERIOD LOOKS TO BE
FAIRLY DRY AS CANADIAN HIGH PRESSURE SLIDES THROUGH THE UPPER GREAT
LAKES REGION.
FIRST...THE UPPER TROUGH THAT HAS BEEN INFLUENCING THE WEATHER FOR
THE START OF THE WORK WEEK WILL BE SITUATED OVER WISCONSIN AND IOWA
AND SHIFTING EAST THROUGH THE GREAT LAKES REGION ON WEDNESDAY
NIGHT. MEANWHILE...THE SURFACE LOW WILL BE LOCATED OVER LOWER
MICHIGAN AT 00Z THURSDAY AND BEGIN TO MOVE UP THE ST LAWRENCE
SEAWAY WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE INTENSIFIES THE
LOW. AS THIS OCCURS...HIGH PRESSURE ORIGINATING FROM NORTH CENTRAL
CANADA WILL BE MOVING A RIDGE INTO THE UPPER MISSISSIPPI VALLEY ON
WEDNESDAY NIGHT AND THE UPPER GREAT LAKES ON THURSDAY. WITH THE
UPPER TROUGH AND CLOSE PROXIMITY OF THE LOW...THERE WILL STILL BE
DEEPER MOISTURE AND 850-700MB Q-VECTOR CONVERGENCE OVER THE
SOUTHEAST HALF OF THE CWA. IN ADDITION...WITH THE INCREASING
NORTHERLY 850-700MB FLOW OVER THE AREA MODELS ARE CONSISTENT ON AN
AREA OF FGEN SETUP FROM IRONWOOD THROUGH EASTERN LAKE SUPERIOR AT
00Z THURSDAY. THEN AS THE LOW SHIFTS EAST...THE FGEN WILL SLIDE
SOUTHEAST THROUGH THE NIGHT AND LIKELY EXIT THE MOST IF NOT ALL OF
THE CWA BY 12Z THURSDAY. AT THIS POINT...THINKING THAT THE MOVEMENT
OF THE PRECIPITATION SHOULD KEEP AMOUNTS UNDER A QUARTER OF AN
INCH.
CANADIAN HIGH PRESSURE THEN BECOMES THE DOMINATING FEATURE FOR THE
REST OF THE PERIOD...AS THE AREA IS UNDER NORTHWEST FLOW ALOFT.
THIS DRY CANADIAN AIR AND COOLER NORTHERLY LOW LEVEL WINDS WILL
LEAD TO NICE BUT SLIGHTLY COOLER THAN NORMAL START TO THE MEMORIAL
DAY WEEKEND. THE STRONGEST NORTHERLY FLOW OFF LAKE SUPERIOR WILL BE
ON THURSDAY WITH THE CLOSER PROXIMITY OF THE EXITING LOW. THIS WILL
KEEP TEMPERATURES COOLER THAN MOST OF THE DAYS...WITH HIGHS IN THE
UPPER 40S NEAR LAKE SUPERIOR AND IN THE 50S INLAND. FRIDAY-SUNDAY
WILL BE DOMINATED BY LAKE BREEZES EACH DAY...WITH THE WARMEST
TEMPERATURES OVER THE INTERIOR LOCATIONS /60S/. THERE ARE HINTS OF A
COUPLE WEAK SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT
FRI-SUN...BUT WILL THE DRY AIR IN PLACE...WOULDN/T EXPECT MUCH FOR
PRECIPITATION CHANCES. UNDER THE HIGH PRESSURE RIDGE ON THURSDAY
NIGHT...EXPECT TO SEE SOME SUB FREEZING LOWS OVER THE INTERIOR
PORTIONS OF UPPER MICHIGAN. PWAT VALUES AROUND 40 PERCENT OF NORMAL
AND LIGHT WINDS WOULD BE FAVORABLE WELL BELOW NORMAL LOWS. MAV/MET
GUIDANCE PICKING UP ON THIS IDEA WITH LOWS BETWEEN 25-30 OVER THE
WEST AND THAT SEEMS FAIRLY REASONABLE. HAVE TRENDED THAT DIRECTION
AND LOWERED TEMPS OVER THE WEST AROUND 5 DEGREES. FROST/FREEZE
HEADLINES DON/T START UNTIL MEMORIAL DAY...SO THERE WON/T BE ANY
HEADLINES...BUT ANYONE THAT HAS PLANTED EARLY WILL NEED TO PREPARE
FOR A POTENTIAL FROST/FREEZE.
UPPER RIDGING THAT WILL BE NEARLY STATIONARY JUST EAST OF THE
NORTHERN ROCKIES DURING THIS PERIOD WILL BEGIN TO SHIFT EAST ON
SUNDAY NIGHT AS THE UPPER TROUGH OVER THE NEW ENGLAND STATES SHIFTS
EAST INTO THE ATLANTIC. THIS WILL START A GRADUAL WARMING TREND
TOWARDS MEMORIAL DAY AND INTO THE FIRST PART OF NEXT WEEK. IN
ADDITION...IT WILL ALSO BRING BETTER OPPORTUNITIES FOR SHORTWAVES
TO RIDE OVER THE RIDGE AND INTO THE AREA LATER MONDAY AND MORE
LIKELY TOWARDS TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 745 PM EDT TUE MAY 21 2013
COOL/MOIST AIR UPSLOPING OFF LAKE SUPERIOR WILL LIKELY RESULT IN
LIFR CONDITIONS AT KIWD/KCMX/KSAW THRU THE NIGHT. EXPECT -SHRA AT
TIMES ALONG WITH SOME -DZ. DRIER AIR MAY BEGIN TO MAKE INROADS FROM
THE N DURING THE DAY WED AS LOW PRES THAT HAS PLAGUED THE AREA IN
RECENT DAYS CONTINUES TO WEAKEN AND HIGH PRES BEGINS TO NOSE S
TOWARD THE UPPER LAKES. IF SO...KCMX SHOULD IMPROVE TO LOW MVFR IN
THE AFTN AND KIWD MAY IMPROVE TO IFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT TUE MAY 21 2013
GIVEN WIDESPREAD AREA OF RA THAT IMPACTED MUCH OF LAKE SUP INTO THIS
MORNING...SOME RECENT SHIP OBS THAT INDICATED LO VISIBILITY...AND
SHALLOW COOL AIRMASS OVER THE LAKE...OPTED TO EXTENDED DENSE FOG
ADVY THRU TONIGHT. ARRIVAL OF DRIER AIR FROM THE NW ON WED WILL
SLOWLY DIMINISH THE FOG. OTHERWISE...NE WINDS UP TO 25 TO 30 KTS...
WITH SOME GALE FORCE GUSTS AT THE HIER PLATFORMS...WILL CONTINUE
STRONGEST OVER WESTERN LAKE SUP WHERE TERRAIN FUNNELING WILL ENHANCE
THE WIND SPEEDS.
GUSTY NORTHERLY WINDS ARE EXPECTED BEHIND THE LOW PRESSURE SYSTEM
ON WEDNESDAY NIGHT INTO THURSDAY...BUT LINGERING WARM AIR ALOFT
SHOULD KEEP WINDS IN 20-25KT RANGE. THEN...A HIGH PRESSURE RIDGE
BUILDING SOUTHEAST OVER THE UPPER GREAT LAKES FOR THURSDAY NIGHT
THROUGH THE WEEKEND WILL BRING LIGHT WINDS TO LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 6 AM EDT /5 AM CDT/ WEDNESDAY FOR
LSZ162-243>249-263>267.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ221-248-250.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
736 PM EDT TUE MAY 21 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 315 PM EDT TUE MAY 21 2013
AN AREA OF LOW PRESSURE WILL DEVELOP OVER SOUTHEAST MISSOURI THIS
EVENING AND MOVE THROUGH CENTRAL MICHIGAN ON WEDNESDAY. THE
DEVELOPING LOW CENTER WILL BRING SOAKING RAINS AND A FEW STRONG
THUNDERSTORMS TO THE AREA LATE TONIGHT AND WEDNESDAY. MUCH COOLER
AIR AND SHOWERS WILL WRAP IN FROM THE NORTHWEST AS THE LOW DEPARTS
ON THURSDAY. CANADIAN HIGH PRESSURE WILL BUILD OVER THE REGION
THURSDAY NIGHT AND PROVIDE COOL AND DRY WEATHER THROUGH THE HOLIDAY
WEEKEND. THERE WILL ALSO BE A GOOD CHANCE OF A SCATTERED FROST ON
BOTH FRIDAY AND SATURDAY MORNING.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT TUE MAY 21 2013
THREATS ARE THREE FOLD NEXT FEW DAYS WITH ISOLATED STRONG/SEVERE
STORMS THIS EVENING...HEAVY RAIN AND POSSIBLE LOCAL FLOOD POTENTIAL
ON WEDNESDAY... AND THEN MUCH COOLER AIR WITH A LATE SEASON FROST
THREAT BOTH FRI AND SAT MORNING...
LIKE RECENT HRRR GUIDANCE INDICATING ISOL TO SCATTERED TSTORM
COVERAGE SOUTH AND EAST OF KBEH...KY70...KMOP LINE THIS EVENING.
OVERALL COVERAGE AND POTENTIAL FOR ORGANIZATION WILL BE SUPPRESSED
BY MODEST SHORTWAVE RIDGING AND UPPER CONVERGENCE. INITIAL FOCUS IS
AN AXIS OF 1000 J/KG MUCAPE STRETCHING FROM KGRR TOWARDS THE THUMB.
THAT COMBINED WITH 35KTS BULK 0-6KM SHEAR WILL LIKELY GIVE RISE TO
SOME STRONG AND POSSIBLY SEVERE PULSE TYPE STORMS.
HEAVY RAIN THREAT ON WEDNESDAY WITH SFC CYCLOGENESIS AND MID LEVEL
FRONTOGENESIS AS NICE SHORTWAVE MOVES NORTHEASTWARD FROM MO/AR THIS
EVENING CROSSING THE REGION WED. BOTH ECMWF AND GFS AS WELL AS SOME
OF THE SHORTER TERM MESO GUIDANCE ALL INDICATE A 75 WIDE 1-2 INCH
BAND OF RAIN ORIENTED SSW TO NNE ON WEDNESDAY. THE MOISTURE AND
DYNAMICS ARE CERTAINLY IN POSITION TO SUPPORT THE RAINFALL...IT IS
JUST WHERE THE AXIS OF THE HEAVIER RAINFALL WILL BE. AT THIS POINT
FEEL THE BEST BET WOULD BE JUST ABOUT ON A KAZO...KGRR...KMOP LINE
WITH KMKG ABOUT AS FAR WEST AS IT MIGHT BE AND KLAN AS FAR EAST.
WRAP AROUND MOISTURE AND MUCH COOLER AIR MOVE IN BY THURSDAY AS
UPPER LOW OVER MN OPENS AND SWINGS EASTWARD THROUGH THE REGION. H85
TEMPS DROP TO NEAR ZERO BY THU EVENING WITH MUCH DRIER SFC DEWPOINT
DRIVING INTO THE REGION AS UPSTREAM CANADIAN SFC HIGH BUILD
OVERHEAD. FEEL PRETTY CONFIDENT ABOUT FROST POTENTIAL FRI AND SAT
MORNING...ESPECIALLY UP NORTH AND IN SHELTERED LOW LYING AREAS
EVERYWHERE. NOT SURE WHICH MORNING WILL BE THE COLDER...FRI HAS THE
COLDER OVERALL AIRMASS BUT BOUNDARY LAYER WINDS WILL INHIBIT
RADIATIONAL COOLING.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 315 PM EDT TUE MAY 21 2013
THE LONG TERM PORTION OF THE FCST PERIOD LOOKS RATHER QUIET FOR
LOWER MICHIGAN. THE UPPER AIR PATTERN WILL TAKE ON SOME OF THE
CHARACTERISTICS OF AN OMEGA BLOCK. THIS OCCURS AS THE TROUGH/LOW
MOVING THROUGH MID WEEK HELPS TO ESTABLISH AN UPPER LOW ACROSS THE
NE U.S. AND THE CANADIAN MARITIMES. AN UPPER LOW WILL BECOME
ESTABLISHED ACROSS THE WRN U.S. COAST...WITH A RIDGE HOLDING ON IN
THE CENTRAL PORTION OF THE COUNTRY.
LOWER MICHIGAN SHOULD END UP UNDER THE DRY PORTION DOWNSTREAM OF THE
RIDGE AS IT SITS ALMOST STATIONARY. COOL NW FLOW ALOFT WILL KEEP
HIGHS IN THE 60S FROM FRI AND LIKELY THROUGH SUN WITH H850 TEMPS
ROUGHLY FROM 3-5C. WE STILL ARE EXPECTING SOME FROST POTENTIAL UP
NORTH ON FRI NIGHT BEFORE THE AIR MASS MODERATES SOME FOR THE
REMAINDER OF THE WEEKEND.
A WEAK SHORT WAVE WILL PUSH THROUGH THE REGION LATE SUN AND SUN
NIGHT. RIGHT NOW IT SEEMS THAT THIS SHOULD MOVE THROUGH DRY AS THE
LONG WAVE RIDGE SHOULD OVERCOME THIS WEAK SHORT WAVE. ALSO THE AIR
MASS SHOULD BE FAIRLY DRY WITH THE RIDGE SITTING OVER THE AREA FOR A
FEW DAYS AND NO GOOD MOISTURE ADVECTION EXPECTED THROUGH SUN.
SOME SPORADIC MODEL RUNS HAD BEEN SHOWING A WARM FRONT APPROACHING
LATE SUN AND REMAINING THROUGH TUE. THIS WOULD HAVE BROUGHT SOME
RAIN CHCS TO THE AREA. IT APPEARS NOW THAT THE NW FLOW ALOFT SHOULD
KEEP THIS FRONT SW OF THE AREA UNTIL AT LEAST TUE BEFORE SOME LOW
CHCS OF SHOWERS/STORMS WOULD DEVELOP. TEMPS WILL WARM INTO THE 70S
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 737 PM EDT TUE MAY 21 2013
EXPECT VFR CONDITIONS THIS EVENING...THERE COULD BE SOME ISOLATED
SHOWERS AND THUNDERSTORMS FROM AZO TO JXN HOWEVER. THEN MVFR
CONDITIONS DEVELOP BY 12Z WEDNESDAY AS SHOWERS AND A FEW
THUNDERSTORMS MOVE IN. WINDS WILL BE FROM THE SOUTHWEST AOB 10
KNOTS.
&&
.MARINE...
ISSUED AT 315 PM EDT TUE MAY 21 2013
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED ON THURSDAY AS COLDER AIR
WRAPS IN BEHIND DEPARTING LOW PRESSURE SYSTEM. HIGH PRESSURE WILL
BRING QUIET AND COOL CONDITIONS FOR MOST IF NOT ALL OF THE HOLIDAY
WEEKEND.
&&
.FIRE WEATHER...
ISSUED AT 315 PM EDT TUE MAY 21 2013
THE AREA WILL SEE PERIODS OF RAIN THROUGH THURSDAY. OVER AN INCH OF
RAIN IS LIKELY KEEPING THE FIRE RISK LOW.
&&
.HYDROLOGY...
ISSUED AT 315 PM EDT TUE MAY 21 2013
PERIODS OF HEAVIER RAIN IS EXPECTED BY LATE TONIGHT AND SHOULD
LINGER UNTIL THURSDAY. SOME TYPICAL LOCALIZED FLOODING IS POSSIBLE
BY WEDNESDAY AFTERNOON IN LOW LYING URBAN AND RURAL AREAS AND ON
SMALL STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DKC
SHORT TERM...DKC
LONG TERM...NJJ
AVIATION...OSTUNO
FIRE WEATHER...DKC
HYDROLOGY...DKC
MARINE...DKC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
412 PM EDT MON MAY 20 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 409 PM EDT MON MAY 20 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO OVER
THE NRN PLAINS UPSTREAM OF UPR RDG EXTENDING FM THE CENTRAL GRT LKS
INTO THE SE CONUS. DRY SLOTTING ALF TO THE E OF THIS FEATURE AS
SHOWN BY HIER 12Z H85 AND H7 DEWPT DEPRESSIONS AT GRB/DAVENPORT IA
HAS TENDED TO STUNT SHRA DVLPMENT OVER THE W HALF OF THE CWA...BUT
MORE PERSISTENT AXIS OF GREATER MSTR/HIER KINX OVER THE ERN CWA AND
SHRTWV MOVING NE FM WI HAS LED TO MORE SHRA/ELEVATED TS IN THAT
AREA. LO CLDS HAVE LINGERED N OF SFC WARM FNT AS WELL EXCEPT OVER
THE W...WHERE SOME LLVL DRYING/DAYTIME HEATING HAVE TENDED TO MIX
OUT THE LO CLDS AND BOOST TEMPS INTO THE 70S. TO THE W...12Z MPX
RAOB SHOWS A MUCH MOISTER AIRMASS. SOME SHRA ARE DVLPG IN WRN WI
WITH DAYTIME HEATING/DESTABILIZATION ON THE ERN EDGE OF THIS DEEPER
MSTR. FARTHER TO THE SW...ANOTHER SHRTWV IS ROTATING ARND THE CLOSED
LO AND THRU THE SCENTRAL PLAINS.
CHALLENGING FCST THRU THE SHORT TERM. BUT WITH CUTOFF LO SWIRLING TO
THE W...TENDED TO FOLLOW THE LEAST PROGRESSIVE MODELS FOR FCST
PREPARATION.
TNGT...EXPECT UPR DRY SLOT TO BRING A RELATIVELY QUIET LATE AFTN/
EARLY EVNG TIME TO THE CWA PER MOST OF RECENT HI RES GUIDANCE.
EXPECT LINGERING SHRA/TS OVER THE E TO END LATE THIS AFTN WITH
DRYING AT H85-7 SLOWLY PUSHING AXIS OF HIER MSTR TO THE E. SHRA NOW
DVLPG IN WRN WI E OF MOISTER AIRMASS SHOWN ON THE 12Z MPX RAOB AND
NEAR THE WRN EDGE OF THE DRY SLOT MAY IMPACT THE WRN ZNS THIS EVNG
AS THEY DRIFT NWD IN THE SLY FLOW ALF E OF THE UPR LO...SO CARRIED
CHC POPS IN THIS AREA THRU THE EVNG. LATER TNGT...PREFERRED 12Z
GFS/REG CNDN MODELS SHOW MORE SHRA/TS ARRIVING OVER THE SCENTRAL
COUNTIES AS SHRTWV NOW MOVING THRU THE SCENTRAL PLAINS ACCOMPANIED
BY JET MAX/UPR DVGC CORE ROTATES NEWD AHEAD OF THE NEARLY STNRY
CLOSED LO TO THE W. FCST LIKELY POPS ARRIVING LATE IN THIS AREA.
OTRW..TENDED TOWARD THE HIER END OF GUIDANCE FOR MIN TEMPS EXCEPT
NEAR THE GREAT LKS.
TUE...SHRA/SOME TS ASSOCIATED WITH DISTURBANCE LIFTING NEWD E OF THE
MAIN CLOSED LO WL IMPACT MAINLY THE CENTRAL/ERN ZNS IN THE MRNG
BEFORE GIVING WAY TO MID LVL DRYING. APRCH OF ANOTHER DISTURBANCE FM
THE SSW ROTATING ARND THE CLOSED LO MAY BRING ANOTHER BATCH OF
SHRA/TS NEAR THE WI BORDER LATER IN THE DAY. HI TEMPS FCST WL BE
TRICKY. THE CNDN MODEL HINTS AT MORE OF A SFC WAVE RIDING THRU THE
ECENTRAL AND HINTS THERE COULD BE MORE SUNSHINE IN THIS AREA IN THE
AFTN. RIGHT NOW...PLAYED THE FCST FOR MORE CLDS/A LLVL NE FLOW OFF
THE COOL WATERS OF LK SUP TO THE N OF STNRY FNT JUST TO THE W.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 409 PM EDT MON MAY 20 2013
THE FOCUS OF THE LONG TERM FORECAST THIS WEEK WILL BE THE PASSING OF
A LOW PRESSURE SYSTEM ACROSS THE GREAT LAKES REGION. CLOSED 500MB
LOW OVER THE NORTHERN PLAINS THIS AFTERNOON WILL MAKE ITS WAY JUST
SOUTH OF UPPER MICHIGAN ON WEDNESDAY...GRADUALLY FILLING AS IT
REACHES THE EASTERN SEABOARD BY FRIDAY AFTERNOON. THIS LOW EXTENDS
FROM A TROUGH ASSOCIATED WITH STRONGER LOW PRESSURE SITUATED OVER
NORTHERN QUEBEC. AT THE 300MB LEVEL LEFT EXIT REGION DIVERGENCE HAS
HELPED WITH THE DEVELOPMENT OF THE LOW PRESSURE SYSTEM OVER THE
PLAINS. THIS JET WILL SHIFT NORTHWARD AND BY WEDNESDAY UPPER
MICHIGAN WILL BE SLIGHTLY NORTH OF THE BEST UPPER LEVEL SUPPORT...IN
THE RIGHT ENTRANCE REGION. 850-500MB QVECTOR CONVERGENCE SHOWS BEST
LIFT GENERALLY ALONG SOUTHWESTERN-SOUTHERN UPPER MI/LOWER
MI/WISCONSIN ACCORDINGLY. MEANWHILE...A WEAK SURFACE LOW DEVELOPING
IN THE PLAINS MOVES NORTHWARD ALONG THE TROUGH...PASSING THROUGH
LOWER MI AND THE LOWER GREAT LAKES WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT. MODEL SOUNDINGS SHOW ABUNDANT MOISTURE REMAINS
THROUGH ALL OF WEDNESDAY FOR CENTRAL/EASTERN UPPER MI BEFORE THE
VERY DRY AIRMASS/HIGH PRESSURE ARRIVES WEDNESDAY NIGHT/THURSDAY.
PWATS DURING THIS TIME STILL REMAIN AS HIGH AS 150 PERCENT OF
NORMAL. HAVE A DIMINISHING TREND FOR POPS FROM WEDNESDAY AFTERNOON
ONWARD AS DRY AIR INFILTRATES THE AREA AND THE SFC LOW EXITS THE
REGION. ADDITIONALLY...WITH ABUNDANT MOISTURE IN PLACE EXPECTING FOG
ACROSS LAKE SUPERIOR AND LAKE MICHIGAN FOR TUESDAY NIGHT/EARLY
WEDNESDAY AFTERNOON. ONCE THE DRIER AIR MOVES IN THE FOG WILL
DISSIPATE.
UPPER LEVEL HIGH OVER THE CANADIAN PRAIRIE WILL SINK SOUTHWARD AND
MERGE WITH THE BUILDING RIDGE OVER THE CENTRAL UNITED STATES ON
THURSDAY MORNING...BRINGING AN END TO PRECIPITATION FOR UPPER MI.
WITH DRY AIR SCOURING OUT THE CLOUDS...NORTHERLY WINDS...AND 850MB
TEMPS AROUND 2-4C...THURSDAY AFTERNOON LOOKS TO BE MOSTLY SUNNY WITH
TEMPS IN THE MID-UPPER 50S AND MAYBE EVEN LOW 60S....BELOW NORMAL BY
LATE MAY STANDARDS. MIXED LAYER DEWPOINTS BRING DEWPOINTS INTO THE
UPPER 20S/30S WHICH BRINGS MINIMUM RH FIELDS TO 30-40 PERCENT FOR
MID AFTERNOON ON THURSDAY.
A SHORTWAVE ROTATING AROUND THE 500MB LOW IN QUEBEC WILL PASS
OVERHEAD FRIDAY AFTERNOON BUT WITH DRY AIR FIRMLY IN PLACE NOTHING
WILL COME OF IT BEYOND SOME SCATTERED CLOUDS. AFTER FRIDAY THE UPPER
LEVEL RIDGE WILL SPRAWL ACROSS MUCH OF THE CENTRAL AND EASTERN
UNITED STATES. THIS WILL KEEP A DRIER AIRMASS IN PLACE AND KEEP
CONDITIONS QUIET THROUGH SATURDAY AFTERNOON. A LOW PRESSURE
TROUGH/SHORTWAVE WILL MOVE INTO THE GREAT LAKES AREA SATURDAY
EVENING INTO MONDAY...BRINGING A CHANCE FOR RAIN SHOWERS INTO THE
CWA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 134 PM EDT MON MAY 20 2013
CHALLENING AVIATION FCST TODAY. BUT WITH CWA N OF SFC WARM FNT AND
STEADY UPSLOPE E-SE WIND...EXPECT PREDOMINANT IFR CONDITIONS TO
PERSIST THRU THE FCST PERIOD AT SAW AND ESPECIALLY CMX...WHERE
LIFR/VLIFR CONDITIONS WL PREVAIL INTO THIS EVNG. DOWNSLOPING FLOW
AND DAYTIME HEATING/MIXING SHOULD MAINTAIN VFR CONDITIONS AT IWD
THRU THE AFTN...BUT EXPECTED WSHFT TO THE NE OFF COOL/MOIST LK SUP
THIS EVNG/TUE SHOULD BRING IFR CONDITIONS OVER THAT SITE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 PM EDT MON MAY 20 2013
NE GALES OVER FAR WESTERN LAKE SUP WITH FAVORABLE TERRAIN FUNNELING
OF THAT FLOW WILL TEND TO DIMINISH TO 20 TO 25 KT THIS EVENING WITH
WEAKENING PRES GRADIENT. WILL LET GALE WARNING EXPIRE AT 03Z.
OTHERWISE...EXPECT PATCHY FOG TO SLOWLY DISSIPATE FROM THE N BY
LATER TUE WITH GRADUAL ARRIVAL OF DRIER AIR IN PERSISTENT NE FLOW TO
THE S OF HI PRES OVER ONTARIO.
A LOW PRESSURE SYSTEM WILL PASS JUST SOUTH OF LAKE SUPERIOR
WEDNESDAY. WINDS WILL BECOME MORE NORTHERLY AS THE LOW MOVES EASTWARD
ON THURSDAY BUT ARE EXPECTED TO REMAIN LESS THAN 25 KNOTS. HIGH
PRESSURE WILL FILTER IN BEHIND THE LOW THURSDAY EVENING AND REMAIN
THROUGH THE WEEKEND...KEEPING WINDS GENERALLY LESS THAN 20 KNOTS. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MCD
AVIATION...KC
MARINE...MCD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 PM EDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1000 AM EDT MON MAY 20 2013
BASED ON DRYNESS ARND H85 AS SHOWN ON THE 12Z GRB RAOB...WHERE THE
H85 DEWPT DEPRESSION WAS 11C...TENDED TO TRIM POPS A BIT FOR TODAY.
LATEST RUC MODEL SHOWS THIS DRY AIR OVERSPREADING THE CWA THRU THE
AFTN. MAINTAINED THE HIER CHC POPS OVER THE E HALF OF THE CWA...
WHERE HIER H85 DEWPTS ARE PROGGED TO LINGER LONGER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM EDT MON MAY 20 2013
UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER SD WITH A
DEEP TROUGH ACROSS THE PLAINS STATES AND A 500 MB RIDGE IN THE UPPER
GREAT LAKES. THE RIDGE GETS PUSHED FURTHER TO THE EAST OVER THE
LOWER GREAT LAKES THIS FORECAST PERIOD WHILE THE TROUGH HEADS SLOWLY
EAST WITH THE 500 MB LOW NOT MOVING VERY MUCH AT ALL.
850-500 MB Q-VECTOR CONVERGENCE AND DEEP MOISTURE REMAIN FOR THIS
FORECAST PERIOD AND THE NAM...ECMWF AND GFS SHOW THIS. TRICKY
FORECAST COMING UP WITH AMOUNT OF CLOUD COVER DUE TO CONVECTION
BEING HARD TO DETERMINE AND THIS OF COURSE WILL HAVE AN EFFECT ON
TEMPERATURES. THE MORE SUN THAT WE SEE...THE WARMER THE TEMPERATURES
WILL BE AND THE GREATER THE INSTABILITY FOR THE THUNDERSTORMS TO
WORK WITH. TEMPERATURES HAVE A BIG BUST POTENTIAL FOR TODAY WITH
CLOUD COVER BEING THE BIG QUESTION. THOUGHT THERE WOULD BE SOME
LIMITED SUNSHINE AND ENDED UP WARMING HIGH TEMPERATURES A FEW
DEGREES...ESPECIALLY OVER THE EAST WHERE THAT AREA IS FURTHER FROM
THE STRONG FORCING AND HAS SOME DRIER AIR AWAY FROM THE SFC WARM
FRONT. DID GRADUALLY BRING HIGH POPS OVER THE CWA TODAY AS SYSTEM
DRAWS CLOSER AND KEPT LIKELY POPS IN FOR TONIGHT AS THERE WILL
PROBABLY BE AN MCS/MCC IN THE AREA BRINGING WIDESPREAD RAINFALL TO
THE AREA. DID NOT HAVE ANY TIME TO LOOK AT SEVERE WEATHER
POTENTIAL...BUT THINKING IS THERE COULD BE A FEW STORMS WITH STRONG
WINDS AND LARGE HAIL AND THE SLIGHT RISK ACROSS THE SOUTHERN CWA
LOOKED REASONABLE. ALL DEPENDS ON AMOUNT OF SUNSHINE SEEN TO THE
SOUTH OF THE AREA AND THAT IS THE QUESTION THAT CANNOT BE ANSWERED
AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 515 AM EDT MON MAY 20 2013
THE NEARLY STEADY STATE 500MB LOW TO OUR WEST WILL CONTINUE TO SPIN
ACROSS THE EASTERN DAKOTAS AND WESTERN MN AT 12Z TUESDAY. EXPECT THE
LOW TO SLIDE EASTWARD ON WEDNESDAY...MERGING WITH THE STRONGER LOW
SPINNING OVER EASTERN HUDSON BAY/NORTHERN QUEBEC. THE BEST CHANCE
FOR CONVECTION WILL LINGER ACROSS THE WI BORDER TUESDAY INTO TUESDAY
EVENING...BEFORE SLOWLY COMING TO AN END. FOG OVER LAKE SUPERIOR
WILL SLOWLY BEGIN TO PUSH TO FAR SOUTHERN PORTIONS OF THE
LAKE...WITH LAKE MICHIGAN FOG LIKELY REMAINING STRONG THROUGH MUCH
OF WEDNESDAY WHEN THE DEEPER MOISTURE EXITS THE REGION.
EXPECT COOL NORTHERLY FLOW TO BE THE RULE FROM THURSDAY ON...AS THE
REINFORCING 500MB TROUGH PUSHES IN FROM THE NW. THE LAST OF THE RAIN
SHOULD BE EXITING EASTERN UPPER MI THURSDAY MORNING. DRY WEATHER
SHOULD BE THE RULE FROM THURSDAY AFTERNOON THROUGH AT LEAST THE END
OF THE FORECAST PERIOD /SUNDAY/...AS HIGH PRESSURE DOMINATES THE
REGION.
850MB TEMPS OFF THE 19/12Z ECMWF FALL TO A RATHER COOL 0 TO -3C
THURSDAY NIGHT INTO EARLY FRIDAY...AS COOL HIGH PRESSURE SINKS IN
FROM THE NNW. THE 20/00Z RUN WARMED UP SLIGHTLY AND LINED UP A BIT
BETTER WITH THE GFS...AROUND 0 TO 2C FRIDAY THROUGH SATURDAY. THE
NORMAL HIGH TEMPS FOR THIS TIME OF YEAR ARE IN THE MID 60S FOR MUCH
OF THE CWA...TO NEAR 70F SOUTH CENTRAL AND NEAR THE WI BORDER. WE
SHOULD BE WELL BELOW NORMAL FOR HIGH TEMPS...IN THE 50S ON THURSDAY.
FRIDAY WILL NOT BE MUCH WARMER...WITH A FEW READINGS IN THE LOW TO
MID 60S NEAR THE WI BORDER.
A HIGH AMPLITUDE RIDGE ACROSS THE CENTRAL U.S. UP THROUGH CENTRAL
CANADA WILL CONTINUE TO BUILD...THANKS THE THE BOOKEND 500MB LOWS
OVER THE PACIFIC NORTHWEST AND ACROSS QUEBEC. LOOK FOR THIS RIDGE TO
SLOWLY EDGE EASTWARD...AND RIGHT ACROSS WI/MN/WESTERN UPPER MI AND
LAKE SUPERIOR BY DAYBREAK MONDAY. WARMER AIR WILL SLOWLY CREEP BACK
IN...BUT WITH NO GREAT SOUTHERLY RETURN FLOW...TEMPERATURES WILL
ONLY MODERATE SLIGHTLY EACH DAY...WITH BELOW NORMAL READINGS AND
RELATIVELY LIGHT WINDS STILL BY SUNDAY AS THE LARGE/STRONG HIGH
PRESSURE SYSTEM CENTERED OVER MUCH OF ONTARIO SINKS CLOSER TO THE
AREA. WHILE BOTH THE GFS AND ECMWF HINT AT A COUPLE OF SHORTWAVES
SINKING IN ON THE NW FLOW ALOFT OVER THE UPCOMING WEEKEND. AT THIS
POINT THERE DOESN/T LOOK TO BE ENOUGH MOISTURE AROUND TO RESULT IN
ANYTHING MORE THAN A FEW CLOUDS. IF ANY SHOWERS OR TS DEVELOP...THEY
WILL LIKELY REMAIN NORTH AND EAST...CLOSER TO THE 500MB AND SFC LOW
ACROSS QUEBEC.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 134 PM EDT MON MAY 20 2013
CHALLENING AVIATION FCST TODAY. BUT WITH CWA N OF SFC WARM FNT AND
STEADY UPSLOPE E-SE WIND...EXPECT PREDOMINANT IFR CONDITIONS TO
PERSIST THRU THE FCST PERIOD AT SAW AND ESPECIALLY CMX...WHERE
LIFR/VLIFR CONDITIONS WL PREVAIL INTO THIS EVNG. DOWNSLOPING FLOW
AND DAYTIME HEATING/MIXING SHOULD MAINTAIN VFR CONDITIONS AT IWD
THRU THE AFTN...BUT EXPECTED WSHFT TO THE NE OFF COOL/MOIST LK SUP
THIS EVNG/TUE SHOULD BRING IFR CONDITIONS OVER THAT SITE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 449 AM EDT MON MAY 20 2013
THE MAIN THREATS FOR THIS PERIOD WILL BE A FEW HIGHER GUSTS AT THE
HIGHEST OBSERVING PLATFORMS...AND THE POTENTIAL FOR FOG. A FEW GUSTS
OF 30-35KTS POSSIBLE THROUGH MONDAY...WITH MOST SITES ABOUT 10KTS
LOWER THANKS TO THE MARINE LAYER. HAVE ALREADY HAD REPORTS OF AROUND
2-5SM VIS OVER W LAKE SUPERIOR...WHICH WILL LIKELY CONTINUE AND
SLOWLY SPREAD E WITH THE BETTER CHANCE OF SHOWERS TODAY. EXPECT FOG
TO LINGER THROUGH TUESDAY /FOR MAINLY S LAKE SUPERIOR/.
EXPECT A RIDGE OVER N MANITOBA TO SLIDE ACROSS JAMES BAY
TONIGHT...AND EXIT E ACROSS QUEBEC TUESDAY NIGHT. IN THE
MEANTIME...A LOW OVER THE EASTERN DAKOTAS AND WESTERN MINNESOTA
TODAY AND TONIGHT SHOULD FILL SLIGHTLY ACROSS SOUTHERN MINNESOTA AND
CENTRAL WISCONSIN ON TUESDAY...AND SLOWLY OVER STRETCHING FROM
SOUTHERN WISCONSIN TO LOWER MICHIGAN DURING THE DAY WEDNESDAY. THE
LOW WILL FINALLY EXIT E ACROSS THE LOWER GREAT LAKES WEDNESDAY
NIGHT. BEHIND THE LOW...STRONG AND COOL HIGH PRESSURE ACROSS N
CENTRAL CANADA WILL EXTEND A RIDGE ACROSS LAKE SUPERIOR LATE
THURSDAY AFTERNOON THROUGH AT LEAST FRIDAY...AND MOST LIKELY THROUGH
THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...07
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
116 PM EDT MON MAY 20 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EDT MON MAY 20 2013
A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING SHOWERS AND
THUNDERSTORMS TO SOUTHERN LOWER MICHIGAN TODAY THROUGH WEDNESDAY. A
FEW STRONG TO SEVERE STORMS ARE POSSIBLE DAILY. COOLER AIR WILL MOVE
IN LATE THIS WEEK.
&&
.UPDATE...
ISSUED AT 1120 AM EDT MON MAY 20 2013
LOW CONFIDENCE SEVERE WEATHER WILL DEVELOP THIS AFTERNOON. SOME
STORMS STILL LOOK LIKE THEY WILL FIRE AT SOME POINT TODAY...THOUGH
EXPECTATIONS ARE THAT A WIDESPREAD SEVERE EVENT WILL NOT OCCUR
THIS AFTERNOON. SOME ADJUSTMENTS TO PRECIPITATION CHANCES THIS
MORNING...OTHERWISE REMAINING FORECAST LEFT ALONE WITH THIS
UPDATE.
SLIGHTLY MORE FAVORABLE SET UP SEEMS TO OCCUR THIS EVENING AND
EARLY TONIGHT AND TUESDAY.
UPDATE ISSUED AT 744 AM EDT MON MAY 20 2013
THAT BAND OF SHOWERS AND ISOLATED THUNDERSTORMS HAS NOW MOVED OUT
OF THE AREA SO I LOWERED POPS THROUGH THE MID MORNING HOURS OVER
THE NORTHERN CWA. THAT WAS ASSOCIATED WITH THE 850 MB WARM FRONT...
WHICH IS NOW NORTH OF THE CWA. IT STILL LOOKS LIKE THE ENERGY FROM
THE CONVECTION SOUTHWEST OF CHICAGO SHOULD REACH OUR CWA EARLY
THIS AFTERNOON TOUCHING OFF A SERIES OF STORMS EARLY TO MID
AFTERNOON.
OVERNIGHT TONIGHT THE LOW LEVEL JET IS AIMED AT SOUTHWEST MICHIGAN
SO I EXPECT ANOTHER PERIOD OF THUNDERSTORMS AFTER MIDNIGHT.
UPDATE ISSUED AT 518 AM EDT MON MAY 20 2013
A FEW SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO DEVELOP ON
THE WARM FRONT FROM BIG SABLE POINT TO NORTHEAST KENT COUNTY AS OF
515 AM THIS MORNING. THE STORMS ARE MOVING NORTHEAST AROUND 40 MPH.
WHILE RAP SOUNDINGS DO SHOW OVER AROUND 100 J/KG OF CIN THERE IS
NEARLY 1000 J/KG OF CAPE ONCE THE CIN IS OVERCOME. I EXPECT THE
STORMS TO CONTINUE TO LIFT NORTH AND EAST OUT OF THE CWA BY 9 AM
THIS MORNING. BASED ON THIS I UPDATED THE GRIDS AND ZONES TO
INDICATE POSSIBLE THUNDERSTORMS FROM I-96 NORTH INTO MID MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 330 AM EDT MON MAY 20 2013
PRIMARY SHORT TERM FCST CONCERNS INVOLVE EVALUATION OF
CONVECTIVE/SVR WX POTENTIAL TODAY THROUGH WEDNESDAY.
A WARM FRONT LIFTING NORTH ACROSS OUR AREA LATER TODAY AND
INCREASING INSTABILITY WILL LEAD TO THE DEVELOPMENT OF SHOWERS AND
STORMS. SOME STRONG TO SEVERE STORMS ARE POSSIBLE PARTICULARLY THIS
AFTERNOON AND EVENING AS SB CAPE VALUES POTENTIALLY REACH AROUND
2000-3000 J/KG NEAR TO SOUTH OF I-96 ALONG WITH STRONGLY NEGATIVE
LI/S AND TOTAL TOTALS INDICES INTO THE MID TO UPPER 50S.
SOME 00Z GUIDANCE FCST SOUNDINGS HAVE AN INVERTED V LOOK BY LATER
THIS AFTN/EVENING SO THERE IS POTENTIAL FOR STRONG TO SEVERE STORMS
TO PRODUCE DAMAGING WIND GUSTS. IN ADDITION LARGE HAIL IS ALSO
POSSIBLE BOTH WITH SFC BASED STORMS AND WITH ELEVATED CONVECTION
NORTH OF THE WARM FRONT. CANNOT RULE OUT AN ISOLATED TORNADO NEAR TO
SOUTH OF THE WARM FRONT THIS AFTERNOON AND EVENING ALTHOUGH THIS
POTENTIAL IS MITIGATED SOMEWHAT BY FAIRLY HIGH LCL HEIGHTS.
SCATTERED STRONG TO POTENTIALLY SVR STORMS ARE POSSIBLE AGAIN
TUESDAY ALTHOUGH WE STILL FEEL THAT POTENTIAL TOMORROW IS NOT AS
GREAT AS LATER TODAY WITH A CONSENSUS OF LATEST 00Z GUIDANCE SHOWING
LESS INSTABILITY/MUCH MORE CLOUD COVER AROUND. THE SVR WX THREAT
TUESDAY WILL BE LARGELY CONTINGENT ON HOW CONVECTIVE EVOLUTION
OCCURS TONIGHT AND ON EXTENT ON CLOUD COVER.
THE SEVERE WX THREAT CONTINUES WEDNESDAY AS THE SFC LOW FINALLY
MOVES EAST INTO MICHIGAN AND AS THE UPPER LEVEL SUPPORT/UPPER TROF
AND ASSOCIATED COLD POOL OF AIR ALOFT MOVE IN. THE 12Z ECMWF/00Z GFS
IN PARTICULAR SUGGEST DECENT SVR WX POTENTIAL WEDNESDAY GIVEN THE
TIMING OF THE SFC LOW AND FRONTAL POSITIONS THROUGH OUR REGION. ALL
THINGS CONSIDERED AT THIS TIME WE BELIEVE THE BEST CHC FOR ORGANIZED
SVR WX WILL BE WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON MAY 20 2013
THE RAIN SHOWERS SHOULD COME TO AN END BY LATE IN THE DAY THURSDAY.
BY THEN THE THREAT FOR THUNDERSTORMS WILL BE SOUTH OF MICHIGAN. A
CANADIAN HIGH WILL MOVE IN FOR THE FRIDAY INTO SATURDAY TIME FRAME.
THIS BRINGS CANADIAN POLAR AIR SOUTH WITH IT SO THERE IS A THE
THREAT OF FROST OVER THE NORTHERN TWO ROWS OF COUNTIES EARLY
SATURDAY MORNING. ANOTHER PACIFIC STORM WILL LIKELY TO TRACK SOUTH
OF THE AREA BUT WILL BRING THE TREAT OF A LIGHT RAIN SHOWERS SUNDAY.
CONFIDENCE IN THIS FORECAST IS ABOUT AVERAGE. THE MODELS ALL AGREE
ON THE OVERALL PATTERN INTO NEXT WEEK. THERE ARE MINOR ISSUES IN THE
DETAILS BUT LITTLE QUESTION THE SYSTEM OVER US NOW WILL BE SHEARED
OUT TO THE EAST BY FRIDAY MORNING. THE LONGWAVE RIDGE WILL SURELY
BUILD TO OUR WEST BEHIND THE DEPARTING SYSTEM. THAT WILL BRING IN
COOLER AIR FRIDAY INTO SATURDAY. THE UPPER RIDGE TO OUR WEST WILL
THEN SLOWLY BUILD EAST OVER TIME PUSHING THE COLD AIR OUT ONCE AGAIN
(EARLY NEXT WEEK). THERE IS SOME QUESTION AS TO WHAT HAPPENS THE
SOME OF THAT PACIFIC SHORTWAVE ENERGY OVER THE WEEKEND AS THE WARM
AIR PUSHES TOWARD US. THE ECMWF KEEPS THE PRECIPITATION SOUTH OF
MICHIGAN THROUGH THE WEEKEND AND THE GFS BRINGS IT IN SUNDAY. I HAVE
LOW CHANCE POPS FOR THAT BUT I AM CURRENTLY THINKING THIS WILL
ACTUALLY MISS US TO THE SOUTH JUST LIKE THE ECMWF SUGGEST.
THE RAIN ON THURSDAY IS DEFORMATION ZONE RELATED AS THE SYSTEM
SHEARS OUT TO THE EAST BUT THERE IS LITTLE OF ANY INSTABILITY WITH
THIS... JUST SHOWERS. THE CONVECTIVE THREAT IS LARGELY OVER BY MID
EVENING WEDNESDAY.
AS FOR THE FROST THREAT... WITH THE CANADIAN HIGH BUILDING IN FRIDAY
INTO SATURDAY... WINDS WILL BECOME LIGHT AND VARIABLE EARLY SATURDAY
MORNING AND SKIES WILL BE CLEAR. DEW POINTS LIKELY WILL FALL INTO
THE LOWER TO MID 30S SO A GOOD SET UP FOR FROST OVER THE NORTHEAST
COUNTIES. AREAS SOUTH OF ROUTE 10 SHOULD STAY WARM ENOUGH FOR THIS
NOT TO BE AN ISSUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 116 PM EDT MON MAY 20 2013
THE MAIN FOCUS OF THE 18Z SET OF FCSTS IS CONVECTION TRENDS
THROUGH THE PERIOD.
A FEW ISOLATED STORMS ARE GOING UP AS OF 1715Z THIS AFTERNOON.
THESE FORMED JUST EAST OF KMKG AND ARE MOVING NORTHEAST AND
STAYING NORTH OF THE REMAINDER OF THE TERMINALS. THERE COULD BE
MORE STORMS THAT FORM NEAR THE LAKESHORE AND MOVE INLAND...BUT
CONFIDENCE IS STILL LIMITED AS TO WHERE ADDITIONAL STORMS...IF ANY
WILL FIRE THIS AFTERNOON. WE HAVE VCTS TO ADDRESS THE CONVECTION
CHCS AND UNCERTAINTY. WE WILL UPDATE THE FCSTS AS NECESSARY IF
CONVECTION IS HEADING TOWARD A SITE. MVFR CONDITIONS CAN BE
EXPECTED UNDER ANY STORMS WITH SOME BRIEF BOUTS OF IFR POSSIBLE.
THE NEXT ROUND OF STORMS SHOULD COME IN AS EARLY AS LATER THIS
EVENING...AND MORE SO OVERNIGHT. THESE STORMS LOOK LIKE THEY WILL
BE MORE WIDESPREAD AND AFFECT ALL OF THE SITES. AGAIN MVFR SHOULD
BE EXPECTED UNDER ANY STORMS WITH BRIEF PERIODS OF IFR ALSO
LIKELY. WE WILL CONTINUE TO FINE TUNE THE CONVECTION OVERNIGHT.
&&
.MARINE...
ISSUED AT 744 AM EDT MON MAY 20 2013
DUE TO THE WATER TEMPERATURES OFF SHORE OF LAKE MICHIGAN ARE IN
THE MID 40S... AND SURFACE DEW POINTS ARE IN THE 60S TODAY PLUS
WINDS ARE NOT ALL THAT STRONG... I EXPECT EXTENSIVE FOG IN THE
NEAR SHORE TO DEVELOP. SO EXPANDED THE FOG INTO THIS AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 330 AM EDT MON MAY 20 2013
WARM AND FAIRLY HUMID WEATHER IS EXPECTED TODAY THROUGH WEDNESDAY.
THUNDERSTORMS WILL BRING LIGHTNING AND GUSTY WINDS AT TIMES TODAY
THROUGH WEDNESDAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT MON MAY 20 2013
SEVERAL ROUNDS OF RAIN AND THUNDERSTORMS ARE EXPECTED TODAY THROUGH
WEDNESDAY BUT SIGNIFICANT FLOODING IS NOT ANTICIPATED SINCE
CUMULATIVE RAINFALL AMOUNTS ON AVERAGE OF ONLY AROUND AN INCH OR TWO
ARE ANTICIPATED THROUGH WEDNESDAY NIGHT. HOWEVER LOCALIZED FLOODING
ISSUES MAY OCCUR WITH HEAVIEST STORMS OR WHERE STORMS TRACK ACROSS
THE SAME LOCATION.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...MACZKO
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...NJJ
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1124 AM EDT MON MAY 20 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT MON MAY 20 2013
A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING SHOWERS AND
THUNDERSTORMS TO SOUTHERN LOWER MICHIGAN TODAY THROUGH WEDNESDAY. A
FEW STRONG TO SEVERE STORMS ARE POSSIBLE DAILY. COOLER AIR WILL MOVE
IN LATE THIS WEEK.
&&
.UPDATE...
ISSUED AT 1120 AM EDT MON MAY 20 2013
LOW CONFIDENCE SEVERE WEATHER WILL DEVELOP THIS AFTERNOON. SOME
STORMS STILL LOOK LIKE THEY WILL FIRE AT SOME POINT TODAY...THOUGH
EXPECTATIONS ARE THAT A WIDESPREAD SEVERE EVENT WILL NOT OCCUR
THIS AFTERNOON. SOME ADJUSTMENTS TO PRECIPITATION CHANCES THIS
MORNING...OTHERWISE REMAINING FORECAST LEFT ALONE WITH THIS
UPDATE.
SLIGHTLY MORE FAVORABLE SET UP SEEMS TO OCCUR THIS EVENING AND
EARLY TONIGHT AND TUESDAY.
UPDATE ISSUED AT 744 AM EDT MON MAY 20 2013
THAT BAND OF SHOWERS AND ISOLATED THUNDERSTORMS HAS NOW MOVED OUT
OF THE AREA SO I LOWERED POPS THROUGH THE MID MORNING HOURS OVER
THE NORTHERN CWA. THAT WAS ASSOCIATED WITH THE 850 MB WARM FRONT...
WHICH IS NOW NORTH OF THE CWA. IT STILL LOOKS LIKE THE ENERGY FROM
THE CONVECTION SOUTHWEST OF CHICAGO SHOULD REACH OUR CWA EARLY
THIS AFTERNOON TOUCHING OFF A SERIES OF STORMS EARLY TO MID
AFTERNOON.
OVERNIGHT TONIGHT THE LOW LEVEL JET IS AIMED AT SOUTHWEST MICHIGAN
SO I EXPECT ANOTHER PERIOD OF THUNDERSTORMS AFTER MIDNIGHT.
UPDATE ISSUED AT 518 AM EDT MON MAY 20 2013
A FEW SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO DEVELOP ON
THE WARM FRONT FROM BIG SABLE POINT TO NORTHEAST KENT COUNTY AS OF
515 AM THIS MORNING. THE STORMS ARE MOVING NORTHEAST AROUND 40 MPH.
WHILE RAP SOUNDINGS DO SHOW OVER AROUND 100 J/KG OF CIN THERE IS
NEARLY 1000 J/KG OF CAPE ONCE THE CIN IS OVERCOME. I EXPECT THE
STORMS TO CONTINUE TO LIFT NORTH AND EAST OUT OF THE CWA BY 9 AM
THIS MORNING. BASED ON THIS I UPDATED THE GRIDS AND ZONES TO
INDICATE POSSIBLE THUNDERSTORMS FROM I-96 NORTH INTO MID MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 330 AM EDT MON MAY 20 2013
PRIMARY SHORT TERM FCST CONCERNS INVOLVE EVALUATION OF
CONVECTIVE/SVR WX POTENTIAL TODAY THROUGH WEDNESDAY.
A WARM FRONT LIFTING NORTH ACROSS OUR AREA LATER TODAY AND
INCREASING INSTABILITY WILL LEAD TO THE DEVELOPMENT OF SHOWERS AND
STORMS. SOME STRONG TO SEVERE STORMS ARE POSSIBLE PARTICULARLY THIS
AFTERNOON AND EVENING AS SB CAPE VALUES POTENTIALLY REACH AROUND
2000-3000 J/KG NEAR TO SOUTH OF I-96 ALONG WITH STRONGLY NEGATIVE
LI/S AND TOTAL TOTALS INDICES INTO THE MID TO UPPER 50S.
SOME 00Z GUIDANCE FCST SOUNDINGS HAVE AN INVERTED V LOOK BY LATER
THIS AFTN/EVENING SO THERE IS POTENTIAL FOR STRONG TO SEVERE STORMS
TO PRODUCE DAMAGING WIND GUSTS. IN ADDITION LARGE HAIL IS ALSO
POSSIBLE BOTH WITH SFC BASED STORMS AND WITH ELEVATED CONVECTION
NORTH OF THE WARM FRONT. CANNOT RULE OUT AN ISOLATED TORNADO NEAR TO
SOUTH OF THE WARM FRONT THIS AFTERNOON AND EVENING ALTHOUGH THIS
POTENTIAL IS MITIGATED SOMEWHAT BY FAIRLY HIGH LCL HEIGHTS.
SCATTERED STRONG TO POTENTIALLY SVR STORMS ARE POSSIBLE AGAIN
TUESDAY ALTHOUGH WE STILL FEEL THAT POTENTIAL TOMORROW IS NOT AS
GREAT AS LATER TODAY WITH A CONSENSUS OF LATEST 00Z GUIDANCE SHOWING
LESS INSTABILITY/MUCH MORE CLOUD COVER AROUND. THE SVR WX THREAT
TUESDAY WILL BE LARGELY CONTINGENT ON HOW CONVECTIVE EVOLUTION
OCCURS TONIGHT AND ON EXTENT ON CLOUD COVER.
THE SEVERE WX THREAT CONTINUES WEDNESDAY AS THE SFC LOW FINALLY
MOVES EAST INTO MICHIGAN AND AS THE UPPER LEVEL SUPPORT/UPPER TROF
AND ASSOCIATED COLD POOL OF AIR ALOFT MOVE IN. THE 12Z ECMWF/00Z GFS
IN PARTICULAR SUGGEST DECENT SVR WX POTENTIAL WEDNESDAY GIVEN THE
TIMING OF THE SFC LOW AND FRONTAL POSITIONS THROUGH OUR REGION. ALL
THINGS CONSIDERED AT THIS TIME WE BELIEVE THE BEST CHC FOR ORGANIZED
SVR WX WILL BE WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON MAY 20 2013
THE RAIN SHOWERS SHOULD COME TO AN END BY LATE IN THE DAY THURSDAY.
BY THEN THE THREAT FOR THUNDERSTORMS WILL BE SOUTH OF MICHIGAN. A
CANADIAN HIGH WILL MOVE IN FOR THE FRIDAY INTO SATURDAY TIME FRAME.
THIS BRINGS CANADIAN POLAR AIR SOUTH WITH IT SO THERE IS A THE
THREAT OF FROST OVER THE NORTHERN TWO ROWS OF COUNTIES EARLY
SATURDAY MORNING. ANOTHER PACIFIC STORM WILL LIKELY TO TRACK SOUTH
OF THE AREA BUT WILL BRING THE TREAT OF A LIGHT RAIN SHOWERS SUNDAY.
CONFIDENCE IN THIS FORECAST IS ABOUT AVERAGE. THE MODELS ALL AGREE
ON THE OVERALL PATTERN INTO NEXT WEEK. THERE ARE MINOR ISSUES IN THE
DETAILS BUT LITTLE QUESTION THE SYSTEM OVER US NOW WILL BE SHEARED
OUT TO THE EAST BY FRIDAY MORNING. THE LONGWAVE RIDGE WILL SURELY
BUILD TO OUR WEST BEHIND THE DEPARTING SYSTEM. THAT WILL BRING IN
COOLER AIR FRIDAY INTO SATURDAY. THE UPPER RIDGE TO OUR WEST WILL
THEN SLOWLY BUILD EAST OVER TIME PUSHING THE COLD AIR OUT ONCE AGAIN
(EARLY NEXT WEEK). THERE IS SOME QUESTION AS TO WHAT HAPPENS THE
SOME OF THAT PACIFIC SHORTWAVE ENERGY OVER THE WEEKEND AS THE WARM
AIR PUSHES TOWARD US. THE ECMWF KEEPS THE PRECIPITATION SOUTH OF
MICHIGAN THROUGH THE WEEKEND AND THE GFS BRINGS IT IN SUNDAY. I HAVE
LOW CHANCE POPS FOR THAT BUT I AM CURRENTLY THINKING THIS WILL
ACTUALLY MISS US TO THE SOUTH JUST LIKE THE ECMWF SUGGEST.
THE RAIN ON THURSDAY IS DEFORMATION ZONE RELATED AS THE SYSTEM
SHEARS OUT TO THE EAST BUT THERE IS LITTLE OF ANY INSTABILITY WITH
THIS... JUST SHOWERS. THE CONVECTIVE THREAT IS LARGELY OVER BY MID
EVENING WEDNESDAY.
AS FOR THE FROST THREAT... WITH THE CANADIAN HIGH BUILDING IN FRIDAY
INTO SATURDAY... WINDS WILL BECOME LIGHT AND VARIABLE EARLY SATURDAY
MORNING AND SKIES WILL BE CLEAR. DEW POINTS LIKELY WILL FALL INTO
THE LOWER TO MID 30S SO A GOOD SET UP FOR FROST OVER THE NORTHEAST
COUNTIES. AREAS SOUTH OF ROUTE 10 SHOULD STAY WARM ENOUGH FOR THIS
NOT TO BE AN ISSUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 744 AM EDT MON MAY 20 2013
MOSTLY VFR TODAY INTO TONIGHT. WHILE THERE IS A THREAT OF SEVERE
STORMS IT IS TO NONE SPECIFIC TO TIME IN THE TAFS. SEEMS THE
CONVECTIVE SYSTEM SOUTHWEST OF CHICAGO WILL BE OUR THREAT FOR
THIS AFTERNOON. THE ISSUE THROUGH IS THE WARM FRONT SEEMS TO BE
OVER NORTH CENTRAL LOWER MICHIGAN SO IT MAY BE THE BEST STORMS
WILL BE NORTH OF ROUTE 10...NORTH OF THE WARM FRONT. THE LOW LEVEL
JET DOES NOT IMPACT THE GRR CWA UNTIL AFTER MIDNIGHT. MOST OF THE
MODEL SOUNDING INTO THIS EVENING NEAR THE TAF SITES ARE VERY DRY
THROUGH 300 MB. THAT IS NOT REAL CONDUCIVE FOR CONVECTION. EVEN
THROUGH SURFACE BASED CAPS ARE NEAR 2000 J/KG.
OVERNIGHT ONCE THE LOW LEVEL JET STARTS BEING AIMED AT LOWER
MICHIGAN AFTER MIDNIGHT... I WOULD EXPECT SHOWERS AND
THUNDERSTORMS TO OVERSPREAD THE TAF SITES SO I DO HAVE SHOWERS IN
THAT TAFS AFTER 09Z.
&&
.MARINE...
ISSUED AT 744 AM EDT MON MAY 20 2013
DUE TO THE WATER TEMPERATURES OFF SHORE OF LAKE MICHIGAN ARE IN
THE MID 40S... AND SURFACE DEW POINTS ARE IN THE 60S TODAY PLUS
WINDS ARE NOT ALL THAT STRONG... I EXPECT EXTENSIVE FOG IN THE
NEAR SHORE TO DEVELOP. SO EXPANDED THE FOG INTO THIS AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 330 AM EDT MON MAY 20 2013
WARM AND FAIRLY HUMID WEATHER IS EXPECTED TODAY THROUGH WEDNESDAY.
THUNDERSTORMS WILL BRING LIGHTNING AND GUSTY WINDS AT TIMES TODAY
THROUGH WEDNESDAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT MON MAY 20 2013
SEVERAL ROUNDS OF RAIN AND THUNDERSTORMS ARE EXPECTED TODAY THROUGH
WEDNESDAY BUT SIGNIFICANT FLOODING IS NOT ANTICIPATED SINCE
CUMULATIVE RAINFALL AMOUNTS ON AVERAGE OF ONLY AROUND AN INCH OR TWO
ARE ANTICIPATED THROUGH WEDNESDAY NIGHT. HOWEVER LOCALIZED FLOODING
ISSUES MAY OCCUR WITH HEAVIEST STORMS OR WHERE STORMS TRACK ACROSS
THE SAME LOCATION.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...MACZKO
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1001 AM EDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1000 AM EDT MON MAY 20 2013
BASED ON DRYNESS ARND H85 AS SHOWN ON THE 12Z GRB RAOB...WHERE THE
H85 DEWPT DEPRESSION WAS 11C...TENDED TO TRIM POPS A BIT FOR TODAY.
LATEST RUC MODEL SHOWS THIS DRY AIR OVERSPREADING THE CWA THRU THE
AFTN. MAINTAINED THE HIER CHC POPS OVER THE E HALF OF THE CWA...
WHERE HIER H85 DEWPTS ARE PROGGED TO LINGER LONGER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM EDT MON MAY 20 2013
UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER SD WITH A
DEEP TROUGH ACROSS THE PLAINS STATES AND A 500 MB RIDGE IN THE UPPER
GREAT LAKES. THE RIDGE GETS PUSHED FURTHER TO THE EAST OVER THE
LOWER GREAT LAKES THIS FORECAST PERIOD WHILE THE TROUGH HEADS SLOWLY
EAST WITH THE 500 MB LOW NOT MOVING VERY MUCH AT ALL.
850-500 MB Q-VECTOR CONVERGENCE AND DEEP MOISTURE REMAIN FOR THIS
FORECAST PERIOD AND THE NAM...ECMWF AND GFS SHOW THIS. TRICKY
FORECAST COMING UP WITH AMOUNT OF CLOUD COVER DUE TO CONVECTION
BEING HARD TO DETERMINE AND THIS OF COURSE WILL HAVE AN EFFECT ON
TEMPERATURES. THE MORE SUN THAT WE SEE...THE WARMER THE TEMPERATURES
WILL BE AND THE GREATER THE INSTABILITY FOR THE THUNDERSTORMS TO
WORK WITH. TEMPERATURES HAVE A BIG BUST POTENTIAL FOR TODAY WITH
CLOUD COVER BEING THE BIG QUESTION. THOUGHT THERE WOULD BE SOME
LIMITED SUNSHINE AND ENDED UP WARMING HIGH TEMPERATURES A FEW
DEGREES...ESPECIALLY OVER THE EAST WHERE THAT AREA IS FURTHER FROM
THE STRONG FORCING AND HAS SOME DRIER AIR AWAY FROM THE SFC WARM
FRONT. DID GRADUALLY BRING HIGH POPS OVER THE CWA TODAY AS SYSTEM
DRAWS CLOSER AND KEPT LIKELY POPS IN FOR TONIGHT AS THERE WILL
PROBABLY BE AN MCS/MCC IN THE AREA BRINGING WIDESPREAD RAINFALL TO
THE AREA. DID NOT HAVE ANY TIME TO LOOK AT SEVERE WEATHER
POTENTIAL...BUT THINKING IS THERE COULD BE A FEW STORMS WITH STRONG
WINDS AND LARGE HAIL AND THE SLIGHT RISK ACROSS THE SOUTHERN CWA
LOOKED REASONABLE. ALL DEPENDS ON AMOUNT OF SUNSHINE SEEN TO THE
SOUTH OF THE AREA AND THAT IS THE QUESTION THAT CANNOT BE ANSWERED
AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 515 AM EDT MON MAY 20 2013
THE NEARLY STEADY STATE 500MB LOW TO OUR WEST WILL CONTINUE TO SPIN
ACROSS THE EASTERN DAKOTAS AND WESTERN MN AT 12Z TUESDAY. EXPECT THE
LOW TO SLIDE EASTWARD ON WEDNESDAY...MERGING WITH THE STRONGER LOW
SPINNING OVER EASTERN HUDSON BAY/NORTHERN QUEBEC. THE BEST CHANCE
FOR CONVECTION WILL LINGER ACROSS THE WI BORDER TUESDAY INTO TUESDAY
EVENING...BEFORE SLOWLY COMING TO AN END. FOG OVER LAKE SUPERIOR
WILL SLOWLY BEGIN TO PUSH TO FAR SOUTHERN PORTIONS OF THE
LAKE...WITH LAKE MICHIGAN FOG LIKELY REMAINING STRONG THROUGH MUCH
OF WEDNESDAY WHEN THE DEEPER MOISTURE EXITS THE REGION.
EXPECT COOL NORTHERLY FLOW TO BE THE RULE FROM THURSDAY ON...AS THE
REINFORCING 500MB TROUGH PUSHES IN FROM THE NW. THE LAST OF THE RAIN
SHOULD BE EXITING EASTERN UPPER MI THURSDAY MORNING. DRY WEATHER
SHOULD BE THE RULE FROM THURSDAY AFTERNOON THROUGH AT LEAST THE END
OF THE FORECAST PERIOD /SUNDAY/...AS HIGH PRESSURE DOMINATES THE
REGION.
850MB TEMPS OFF THE 19/12Z ECMWF FALL TO A RATHER COOL 0 TO -3C
THURSDAY NIGHT INTO EARLY FRIDAY...AS COOL HIGH PRESSURE SINKS IN
FROM THE NNW. THE 20/00Z RUN WARMED UP SLIGHTLY AND LINED UP A BIT
BETTER WITH THE GFS...AROUND 0 TO 2C FRIDAY THROUGH SATURDAY. THE
NORMAL HIGH TEMPS FOR THIS TIME OF YEAR ARE IN THE MID 60S FOR MUCH
OF THE CWA...TO NEAR 70F SOUTH CENTRAL AND NEAR THE WI BORDER. WE
SHOULD BE WELL BELOW NORMAL FOR HIGH TEMPS...IN THE 50S ON THURSDAY.
FRIDAY WILL NOT BE MUCH WARMER...WITH A FEW READINGS IN THE LOW TO
MID 60S NEAR THE WI BORDER.
A HIGH AMPLITUDE RIDGE ACROSS THE CENTRAL U.S. UP THROUGH CENTRAL
CANADA WILL CONTINUE TO BUILD...THANKS THE THE BOOKEND 500MB LOWS
OVER THE PACIFIC NORTHWEST AND ACROSS QUEBEC. LOOK FOR THIS RIDGE TO
SLOWLY EDGE EASTWARD...AND RIGHT ACROSS WI/MN/WESTERN UPPER MI AND
LAKE SUPERIOR BY DAYBREAK MONDAY. WARMER AIR WILL SLOWLY CREEP BACK
IN...BUT WITH NO GREAT SOUTHERLY RETURN FLOW...TEMPERATURES WILL
ONLY MODERATE SLIGHTLY EACH DAY...WITH BELOW NORMAL READINGS AND
RELATIVELY LIGHT WINDS STILL BY SUNDAY AS THE LARGE/STRONG HIGH
PRESSURE SYSTEM CENTERED OVER MUCH OF ONTARIO SINKS CLOSER TO THE
AREA. WHILE BOTH THE GFS AND ECMWF HINT AT A COUPLE OF SHORTWAVES
SINKING IN ON THE NW FLOW ALOFT OVER THE UPCOMING WEEKEND. AT THIS
POINT THERE DOESN/T LOOK TO BE ENOUGH MOISTURE AROUND TO RESULT IN
ANYTHING MORE THAN A FEW CLOUDS. IF ANY SHOWERS OR TS DEVELOP...THEY
WILL LIKELY REMAIN NORTH AND EAST...CLOSER TO THE 500MB AND SFC LOW
ACROSS QUEBEC.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 722 AM EDT MON MAY 20 2013
CHALLENGING FCST WILL CONTINUE OVER THE NEXT DAY OR SO.
REDEVELOPMENT OF PCPN IS LIKELY TODAY...BUT NOT SURE EXACTLY HOW
MUCH OR WHEN IT WILL DEVELOP. WILL HAVE VFR CONDITIONS AT IWD UNTIL
PCPN DEVELOPS BY THIS EVENING AND THEN LOW IFR CIGS WILL MOVE IN
WITH HELP FROM MOISTURE OFF THE LAKE. WHILE THERE MAY BE SHRA/TSRA
AT TIMES...DIFFICULT TO PIN DOWN BEST TIME FRAME. AT KCMX...UPSLOPE
E FLOW THRU THE FCST PERIOD SUGGESTS PREVAILING LIFR CONDITIONS. AT
KSAW...MVFR CONDITIONS WILL LIKELY PREVAIL THRU MUCH OF THE FCST
PERIOD UNTIL THIS EVENING WHEN IFR CONDITIONS MOVE IN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 449 AM EDT MON MAY 20 2013
THE MAIN THREATS FOR THIS PERIOD WILL BE A FEW HIGHER GUSTS AT THE
HIGHEST OBSERVING PLATFORMS...AND THE POTENTIAL FOR FOG. A FEW GUSTS
OF 30-35KTS POSSIBLE THROUGH MONDAY...WITH MOST SITES ABOUT 10KTS
LOWER THANKS TO THE MARINE LAYER. HAVE ALREADY HAD REPORTS OF AROUND
2-5SM VIS OVER W LAKE SUPERIOR...WHICH WILL LIKELY CONTINUE AND
SLOWLY SPREAD E WITH THE BETTER CHANCE OF SHOWERS TODAY. EXPECT FOG
TO LINGER THROUGH TUESDAY /FOR MAINLY S LAKE SUPERIOR/.
EXPECT A RIDGE OVER N MANITOBA TO SLIDE ACROSS JAMES BAY
TONIGHT...AND EXIT E ACROSS QUEBEC TUESDAY NIGHT. IN THE
MEANTIME...A LOW OVER THE EASTERN DAKOTAS AND WESTERN MINNESOTA
TODAY AND TONIGHT SHOULD FILL SLIGHTLY ACROSS SOUTHERN MINNESOTA AND
CENTRAL WISCONSIN ON TUESDAY...AND SLOWLY OVER STRETCHING FROM
SOUTHERN WISCONSIN TO LOWER MICHIGAN DURING THE DAY WEDNESDAY. THE
LOW WILL FINALLY EXIT E ACROSS THE LOWER GREAT LAKES WEDNESDAY
NIGHT. BEHIND THE LOW...STRONG AND COOL HIGH PRESSURE ACROSS N
CENTRAL CANADA WILL EXTEND A RIDGE ACROSS LAKE SUPERIOR LATE
THURSDAY AFTERNOON THROUGH AT LEAST FRIDAY...AND MOST LIKELY THROUGH
THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...07
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
519 AM EDT MON MAY 20 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EDT MON MAY 20 2013
A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING SHOWERS AND
THUNDERSTORMS TO SOUTHERN LOWER MICHIGAN TODAY THROUGH WEDNESDAY. A
FEW STRONG TO SEVERE STORMS ARE POSSIBLE DAILY. COOLER AIR WILL MOVE
IN LATE THIS WEEK.
&&
.UPDATE...
ISSUED AT 518 AM EDT MON MAY 20 2013
A FEW SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO DEVELOP ON
THE WARM FRONT FROM BIG SABLE POINT TO NORTHEAST KENT COUNTY AS OF
515 AM THIS MORNING. THE STORMS ARE MOVING NORTHEAST AROUND 40 MPH.
WHILE RAP SOUNDINGS DO SHOW OVER AROUND 100 J/KG OF CIN THERE IS
NEARLY 1000 J/KG OF CAPE ONCE THE CIN IS OVERCOME. I EXPECT THE
STORMS TO CONTINUE TO LIFT NORTH AND EAST OUT OF THE CWA BY 9 AM
THIS MORNING. BASED ON THIS I UPDATED THE GRIDS AND ZONES TO
INDICATE POSSIBLE THUNDERSTORMS FROM I-96 NORTH INTO MID MORNING.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 330 AM EDT MON MAY 20 2013
PRIMARY SHORT TERM FCST CONCERNS INVOLVE EVALUATION OF
CONVECTIVE/SVR WX POTENTIAL TODAY THROUGH WEDNESDAY.
A WARM FRONT LIFTING NORTH ACROSS OUR AREA LATER TODAY AND
INCREASING INSTABILITY WILL LEAD TO THE DEVELOPMENT OF SHOWERS AND
STORMS. SOME STRONG TO SEVERE STORMS ARE POSSIBLE PARTICULARLY THIS
AFTERNOON AND EVENING AS SB CAPE VALUES POTENTIALLY REACH AROUND
2000-3000 J/KG NEAR TO SOUTH OF I-96 ALONG WITH STRONGLY NEGATIVE
LI/S AND TOTAL TOTALS INDICES INTO THE MID TO UPPER 50S.
SOME 00Z GUIDANCE FCST SOUNDINGS HAVE AN INVERTED V LOOK BY LATER
THIS AFTN/EVENING SO THERE IS POTENTIAL FOR STRONG TO SEVERE STORMS
TO PRODUCE DAMAGING WIND GUSTS. IN ADDITION LARGE HAIL IS ALSO
POSSIBLE BOTH WITH SFC BASED STORMS AND WITH ELEVATED CONVECTION
NORTH OF THE WARM FRONT. CANNOT RULE OUT AN ISOLATED TORNADO NEAR TO
SOUTH OF THE WARM FRONT THIS AFTERNOON AND EVENING ALTHOUGH THIS
POTENTIAL IS MITIGATED SOMEWHAT BY FAIRLY HIGH LCL HEIGHTS.
SCATTERED STRONG TO POTENTIALLY SVR STORMS ARE POSSIBLE AGAIN
TUESDAY ALTHOUGH WE STILL FEEL THAT POTENTIAL TOMORROW IS NOT AS
GREAT AS LATER TODAY WITH A CONSENSUS OF LATEST 00Z GUIDANCE SHOWING
LESS INSTABILITY/MUCH MORE CLOUD COVER AROUND. THE SVR WX THREAT
TUESDAY WILL BE LARGELY CONTINGENT ON HOW CONVECTIVE EVOLUTION
OCCURS TONIGHT AND ON EXTENT ON CLOUD COVER.
THE SEVERE WX THREAT CONTINUES WEDNESDAY AS THE SFC LOW FINALLY
MOVES EAST INTO MICHIGAN AND AS THE UPPER LEVEL SUPPORT/UPPER TROF
AND ASSOCIATED COLD POOL OF AIR ALOFT MOVE IN. THE 12Z ECMWF/00Z GFS
IN PARTICULAR SUGGEST DECENT SVR WX POTENTIAL WEDNESDAY GIVEN THE
TIMING OF THE SFC LOW AND FRONTAL POSITIONS THROUGH OUR REGION. ALL
THINGS CONSIDERED AT THIS TIME WE BELIEVE THE BEST CHC FOR ORGANIZED
SVR WX WILL BE WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON MAY 20 2013
THE RAIN SHOWERS SHOULD COME TO AN END BY LATE IN THE DAY THURSDAY.
BY THEN THE THREAT FOR THUNDERSTORMS WILL BE SOUTH OF MICHIGAN. A
CANADIAN HIGH WILL MOVE IN FOR THE FRIDAY INTO SATURDAY TIME FRAME.
THIS BRINGS CANADIAN POLAR AIR SOUTH WITH IT SO THERE IS A THE
THREAT OF FROST OVER THE NORTHERN TWO ROWS OF COUNTIES EARLY
SATURDAY MORNING. ANOTHER PACIFIC STORM WILL LIKELY TO TRACK SOUTH
OF THE AREA BUT WILL BRING THE TREAT OF A LIGHT RAIN SHOWERS SUNDAY.
CONFIDENCE IN THIS FORECAST IS ABOUT AVERAGE. THE MODELS ALL AGREE
ON THE OVERALL PATTERN INTO NEXT WEEK. THERE ARE MINOR ISSUES IN THE
DETAILS BUT LITTLE QUESTION THE SYSTEM OVER US NOW WILL BE SHEARED
OUT TO THE EAST BY FRIDAY MORNING. THE LONGWAVE RIDGE WILL SURELY
BUILD TO OUR WEST BEHIND THE DEPARTING SYSTEM. THAT WILL BRING IN
COOLER AIR FRIDAY INTO SATURDAY. THE UPPER RIDGE TO OUR WEST WILL
THEN SLOWLY BUILD EAST OVER TIME PUSHING THE COLD AIR OUT ONCE AGAIN
(EARLY NEXT WEEK). THERE IS SOME QUESTION AS TO WHAT HAPPENS THE
SOME OF THAT PACIFIC SHORTWAVE ENERGY OVER THE WEEKEND AS THE WARM
AIR PUSHES TOWARD US. THE ECMWF KEEPS THE PRECIPITATION SOUTH OF
MICHIGAN THROUGH THE WEEKEND AND THE GFS BRINGS IT IN SUNDAY. I HAVE
LOW CHANCE POPS FOR THAT BUT I AM CURRENTLY THINKING THIS WILL
ACTUALLY MISS US TO THE SOUTH JUST LIKE THE ECMWF SUGGEST.
THE RAIN ON THURSDAY IS DEFORMATION ZONE RELATED AS THE SYSTEM
SHEARS OUT TO THE EAST BUT THERE IS LITTLE OF ANY INSTABILITY WITH
THIS... JUST SHOWERS. THE CONVECTIVE THREAT IS LARGELY OVER BY MID
EVENING WEDNESDAY.
AS FOR THE FROST THREAT... WITH THE CANADIAN HIGH BUILDING IN FRIDAY
INTO SATURDAY... WINDS WILL BECOME LIGHT AND VARIABLE EARLY SATURDAY
MORNING AND SKIES WILL BE CLEAR. DEW POINTS LIKELY WILL FALL INTO
THE LOWER TO MID 30S SO A GOOD SET UP FOR FROST OVER THE NORTHEAST
COUNTIES. AREAS SOUTH OF ROUTE 10 SHOULD STAY WARM ENOUGH FOR THIS
NOT TO BE AN ISSUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1208 AM EDT MON MAY 20 2013
EXPECT VFR CONDITIONS THROUGH MUCH OF THE NIGHT. THERE IS STILL A
CHANCE OF SOME SHOWERS WITH MVFR CONDITIONS AFTER MIDNIGHT...BUT
THIS MAY BE IN THE FORM OF DISSIPATING SHOWERS AND SO COVERAGE MAY
BE SPARSE UNTIL MORE MOISTURE ARRIVES LATER ON MONDAY AFTERNOON.
THE COVERAGE AND TIMING OF THUNDERSTORMS ON MONDAY AFTERNOON IS
HARD TO PIN DOWN BUT MVFR AND LOCAL IFR IS POSSIBLE AFTER 18Z
MONDAY.
&&
.MARINE...
ISSUED AT 330 AM EDT MON MAY 20 2013
MINIMAL WAVE ACTION IS EXPECTED EARLY THIS WEEK BUT THUNDERSTORMS
WILL POSE A HAZARD TO MARINERS TODAY THROUGH WEDNESDAY. FOG IS ALSO
A POTENTIAL HAZARD EARLY THIS WEEK AS A MUCH MORE HUMID AIRMASS
OVERRUNS COLD LAKE WATERS.
&&
.FIRE WEATHER...
ISSUED AT 330 AM EDT MON MAY 20 2013
WARM AND FAIRLY HUMID WEATHER IS EXPECTED TODAY THROUGH WEDNESDAY.
THUNDERSTORMS WILL BRING LIGHTNING AND GUSTY WINDS AT TIMES TODAY
THROUGH WEDNESDAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT MON MAY 20 2013
SEVERAL ROUNDS OF RAIN AND THUNDERSTORMS ARE EXPECTED TODAY THROUGH
WEDNESDAY BUT SIGNIFICANT FLOODING IS NOT ANTICIPATED SINCE
CUMULATIVE RAINFALL AMOUNTS ON AVERAGE OF ONLY AROUND AN INCH OR TWO
ARE ANTICIPATED THROUGH WEDNESDAY NIGHT. HOWEVER LOCALIZED FLOODING
ISSUES MAY OCCUR WITH HEAVIEST STORMS OR WHERE STORMS TRACK ACROSS
THE SAME LOCATION.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...OSTUNO
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
352 PM CDT MON MAY 20 2013
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 323 PM CDT MON MAY 20 2013
ALL SYSTEMS APPEAR GO FOR AN ACTIVE NIGHT OF THUNDERSTORMS WITH
SEVERE POTENTIAL AS THE ENVIRONMENT WILL HAVE PLENTY OF INSTABILITY
AND DEEP LAYER SHEAR AROUND 50 KTS. THE AIR MASS OVER THE SOUTHERN
HALF OF MISSOURI HAS RECOVERED FROM EARLIER CONVECTION WITH SBCAPE
AOA 3000 J/KG AND THIS RECOVERY SHOULD CONTINUE TO SPREAD
NORTHWARD THROUGH THE LATE AFTERNOON. SCATTERED THUNDERSTORMS HAVE
DEVELOPED IN SEVERAL CONFLUENT ZONES ACROSS SW MO AND SE KS AND
ARE MOVING TO THE NORTHEAST. ADDITIONAL DEVELOPMENT IS EXPECTED
WITH DISCRETE STORMS POSSIBLE THROUGH EARLY EVENING AND THEN AN
OVERALL TREND FOR RAPID UPSCALE GROWTH INTO A FORWARD PROPAGATING
QLCS FEATURING A MIX MODE OF BOWING SEGMENTS AND EMBEDDED
SUPERCELLS. THIS QLCS IS EXPECTED TO IMPACT A GOOD PORTION OF THE
CWA AS IT MOVES E/NW TONIGHT. SOME LOCALLY HEAVY RAINFALL MAY
OCCUR WHERE TRAINING OCCURS...BUT THE SYSTEM IS NOT EXPECTED TO
PRODUCE A WIDESPREAD HEAVY RAIN/FLASH FLOOD THREAT.
GLASS
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 323 PM CDT MON MAY 20 2013
THE IMPACTS OF THE OVERNIGHT CONVECTION ARE HARD TO GAGE AND WILL
HAVE LARGE RAMIFICATIONS ON THE THUNDERSTORM AND SEVERE THREAT
TUESDAY. ANY ONGOING SHOWERS/THUNDERSTORMS REMNANT FROM OVERNIGHT
ARE LIKELY TO BE LOCATED ACROSS SE MO INTO SW IL DURING THE FIRST
PART OF THE MORNING AND THEN WEAKEN. MODEL GUIDANCE SUGGESTS IT
WILL THEN REMAIN RELATIVELY VOID OF PRECIPITATION WELL INTO MID
AFTERNOON AND THIS SHOULD ALLOW FOR SOME AIR MASS RECOVERY AS
CLOUDS THIN. MID LEVEL LAPSE RATES ARE NOT AS STEEP SO OVERALL
INSTABILITY SHOULD BE LESS THAN THE LAST FEW DAYS...HOWEVER IT SHOULD
BE SUFFICIENT WITH AMPLE DEEP LAYER SHEAR FOR SCATTERED ORGANIZED
THUNDERSTORMS DEVELOPING DURING THE LATER PART OF THE AFTERNOON...RAMPING
UP IN COVERAGE DURING THE EARLY EVENING AS LARGE SCALE ASCENT INCREASES
IN ASSOCIATION WITH A SHORT WAVE ROTATING NEWD FROM EASTERN OK
REGION. ANY RESIDUAL BOUNDARIES WILL PROVIDE FURTHER FOCUS AND
ENHANCE THE SEVERE THREAT. THE LARGE SCALE TROF AND ATTENDANT COLD
FRONT WILL FINALLY MOVE ACROSS THE AREA TUESDAY NIGHT...PASSING
EAST OF THE CWA BY EARLY WEDNESDAY MORNING. DRIER AIR AND COOLER
AIR WILL OVERSPREAD THE AREA ON WEDNESDAY IN THE WAKE OF THE FRONT
AND A SECONDARY COLD FRONT ON WEDNESDAY NIGHT WILL USHER EVEN
COOLER AIR AND HIGH PRESSURE INTO THE AREA.
THE PATTERN WILL BE DOMINATED BY WEAK NW FLOW ON THE BACKSIDE OF
THE UPPER TROF AND LOOKS DRY THURSDAY NIGHT-FRIDAY...THEREAFTER
RETURN FLOW AND WEAK DISTURBANCES PASSING THRU THE PLAINS UPPER
RIDGE AND INTO THE MID/UPPER MS VALLEY WILL BRING A RE-NEWED
CHANCE OF THUNDERSTORMS....ESPECIALLY THE NRN HALF OF THE CWA.
WARMER TEMPERATURES WILL ALSO ACCOMPANY THE RETURN FLOW.
GLASS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 112 PM CDT MON MAY 20 2013
STILL HARD TO PIN DOWN EXACT COVERAGE AND TIMING OF STORMS...SO
KEPT VCTS MENTION AT KCOU THROUGH 03Z TUESDAY AND THROUGH 04Z
TUESDAY AT KUIN. FURTHER EAST OVER STL METRO AREA...HRRR MODEL
INDICATING STORMS TO NOT MOVE IN TIL AFTER 01Z TUESDAY...MAYBE
EVEN LATER...BUT KEPT VCTS MENTION AFTER 01Z TUESDAY FOR
NOW...TAPERING OFF AFTER 07Z TUESDAY. OTHERWISE...EXPECT VFR CIGS AND
GUSTY SOUTH WINDS FOR THIS AFTERNOON...BEFORE DIMINISHING AFTER
SUNSET.
SPECIFICS FOR KSTL...STILL HARD TO PIN DOWN EXACT COVERAGE AND
TIMING OF STORMS...LATEST HRRR MODEL INDICATING STORMS TO NOT MOVE
IN TIL AFTER 04Z TUESDAY...MAYBE EVEN LATER...BUT KEPT VCTS
MENTION AFTER 01Z TUESDAY FOR NOW AS WE COULD SEE STUFF FIRE UP
AHEAD OF MAIN ACTIVITY. STORMS TO TAPER OFF AFTER 07Z TUESDAY.
OTHERWISE...EXPECT VFR CIGS AND GUSTY SOUTH WINDS FOR THIS
AFTERNOON...BEFORE DIMINISHING AFTER SUNSET. ANOTHER ROUND OF
STORMS POSSIBLE AFTER 21Z TUESDAY...SO ADDED VCTS MENTION DURING
THIS PERIOD.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
112 PM CDT MON MAY 20 2013
.UPDATE...
ISSUED AT 112 PM CDT MON MAY 20 2013
TORNADO WATCH ISSUED FOR PORTIONS OF CENTRAL MO...SO UPDATED
ZONES/GRIDS FOR THIS. MORNING ACTIVITY FINALLY EXITING FAR
NORTHEAST PORTIONS OF FORECAST AREA. TIMING OF NEXT ROUND TO BE
LATER THIS AFTERNOON OVER CENTRAL MO AND CONTINUE INTO THIS
EVENING. WITH CLOUDS CLEARING OUT...TEMPERATURES ARE FINALLY
RECOVERING WITH HIGHS IN THE 80S...THOUGH UPPER 70S EXPECTED FAR
NORTH DUE TO EXITING STORMS/CLOUDS.
BYRD
&&
.SHORT TERM...(THROUGH TONIGHT)
ISSUED AT 358 AM CDT MON MAY 20 2013
MORNING CONVECTION WILL CONTINUE TO MOVE EWD THRU THE CWA EARLY
THIS MORNING. CURRENTLY DO NOT ANTICIPATE OUTFLOW FROM THIS
CONVECTION IMPACTING THE CWA LATER TODAY AS IT SHUD CONTINUE WELL
OUTSIDE OF THE CWA.
THE CDFNT CURRENTLY OVER ERN KS WILL MOVE EWD TODAY AND SHUD BE
JUST W OF THE CWA AROUND NOON. WITH THE ENTIRE AREA IN THE WARM
SECTOR...EXPECT AREA TO RECOVER WELL WITH AMPLE INSOLATION.
MDL SOLNS DIFFER REGARDING EXACTLY HOW TSRA WILL UNFOLD TODAY.
CONVECTION ALLOWING MDLS SUGGEST FOCUS WILL BE SW OF THE CWA THIS
AFTERNOON/EVE WITH THIS LINE MOVING NEWD INTO THE AREA LATE
TONIGHT. THE OPR MDLS SUGGEST TSRA WILL DEVELOP JUST AHEAD OF THE
CWA LATE THIS MORNING OR EARLY AFTERNOON. INTERESTINGLY...THE
LOCAL 4KM WRF PROVIDES A MERGER OF THESE TWO SOLNS...WHICH SEEMS
THE MOST LIKELY. WHILE TIMING REMAINS A QUESTION...WHAT DOES FORM
SHUD EVOLVE UPSCALE INTO A LINEAR MODE AS IT MOVES ACROSS THE
AREA. TSRA SHUD BE ON THE ERN EDGE OF THE CWA BY SUNRISE TUES.
LITTLE CHANGE WAS MADE TO TEMPS...KEEPING THE FORECAST AOA THE
WARMEST MOS.
TILLY
.LONG TERM...(MONDAY THROUGH NEXT SUNDAY)
ISSUED AT 331 PM CDT SUN MAY 19 2013
CURRENT INDICATIONS BASED ON THE DETERMINISTIC MODELS AND CONVECTION
ALLOWING MODELS IS THAT ANY THUNDERSTORMS REMAINING FROM THE OVERNIGHT
MCS SHOULD BE IN A DRASTICALLY WEAKENED STATE AT DAYBREAK. GIVEN THAT THE
PRIMARY SHORT WAVE TROF WILL HAVE ALREADY ROTATED NEWD INTO IOWA
AND A VEERED WSWLY LLJ...ANY REMAINING SHOWERS AND THUNDERSTORMS
WILL MOST LIKELY BE LOCATED FROM SOUTHWEST/SOUTH CENTRAL IL ACROSS
SE MO. THESE SHOULD DIMINISH BY MID MORNING AS LARGE SCALE SUBSIDENCE
OVERSPREADS THE REGION. IN THE WAKE OF THIS ACTIVITY AND GIVEN THE
TENDENCY TOWARDS CUMULIFORM CLOUDS...GOOD HEATING WILL COMMENCE.
THIS HEATING COMBINED WITH A MOIST BOUNDARY LAYER AND STEEP MID
LEVEL LAPSE RATES WILL CONTRIBUTE TO MODERATE-STRONG INSTABILITY
AND WEAK CONVECTIVE INHIBITION ACROSS THE ENTIRE AREA BY MID
AFTERNOON. SOUTHWESTERLY DEEP LAYER SHEAR AOA 40 KTS WOULD FAVOR
DISCRETE TO SEMI-DISCRETE SUPERCELLS AS THE DOMINATE STORM MODE
INITIALLY. AT THIS WE ARE EXPECTING A FAVORED WSW-ENE CORRIDOR
FOR STORM DEVELOPMENT AFTER 21Z FROM AROUND JEFFERSON CITY TO
BOWLING GREEN...ALTHO THIS AXIS COULD BE A BIT FURTHER SOUTH
DEPENDING ON ANY RESIDUAL BOUNDARIES. MERGERS AND ADDITIONAL
DEVELOPMENT WITHIN THIS ZONE AND UPSTREAM SHOULD RESULT IN A MIX
OF STORM MODES BY LATE AFTERNOON AND EVENING WITH POTENTIAL FOR
SUPERCELLS AND BOWING LINEAR SEGMENTS. THE OVERALL COVERAGE OF
STORMS SHOULD INCREASE DURING THE EVENING AS THE NEXT UPSTREAM
SHORT WAVE SPREADS LARGE SCALE ASCENT INTO THE REGION...ALSO
CONTRIBUTING TO UPSCALE STORM GROWTH. THERE EVENTUALLY COULD BE A
HEAVY RAIN THREAT FROM CENTRAL THROUGH EAST CENTRAL MO DUE TO
PERSISTENT AND TRAINING CONVECTION...BUT THE EXACT LOCATION IS TOO
DIFFICULT TO PINPOINT AT THIS POINT.
THE CONVECTIVE DETAILS BECOME LESS DEFINED ON TUESDAY DUE TO THE
POTENTIAL FOR RESIDUAL SHOWERS/STORMS FROM MONDAY NIGHT AND THE
PRESENCE OF MESOSCALE BOUNDARIES. THE OVERALL SYNOPTIC PATTERN
FEATURING THE UPPER TROF PROGRESSING EASTWARD WITH THE ATTENDANT
COLD FRONT MOVING THRU THE CWA DURING THE LATE AFTERNOON/EVENING
WOULD FAVOR HIGH THUNDERSTORM CHANCES...ESPECIALLY THE SE HALF OF
THE CWA. DEEP LAYER SHEAR OF 30-40 KTS AND WEAK-MODERATE INSTABILITY
WOULD CONTINUE TO FAVOR ORGANIZED-MIXED MODE SEVERE STORMS.
THE BOUNDARY FINALLY LOOKS TO PASS SOUTH OF THE AREA BY LATE
WEDNESDAY WITH ANOTHER REINFORCING BOUNDARY ON THURSDAY. THE PATTERN
THEN IS DOMINATED BY WEAK NW FLOW ON THE BACKSIDE OF THE UPPER TROF
AND LOOKS DRY THURSDAY NIGHT-SAT MORNING. THEREAFTER RETURN FLOW AND
WEAK DISTURBANCES PASSING THRU THE PLAINS UPPER RIDGE AND INTO THE
MID/UPPER MS VALLEY WILL BRING A RE-NEWED CHANCE OF
THUNDERSTORMS....ESPECIALLY THE NRN HALF OF THE CWA.
GLASS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 112 PM CDT MON MAY 20 2013
STILL HARD TO PIN DOWN EXACT COVERAGE AND TIMING OF STORMS...SO
KEPT VCTS MENTION AT KCOU THROUGH 03Z TUESDAY AND THROUGH 04Z
TUESDAY AT KUIN. FURTHER EAST OVER STL METRO AREA...HRRR MODEL
INDICATING STORMS TO NOT MOVE IN TIL AFTER 01Z TUESDAY...MAYBE
EVEN LATER...BUT KEPT VCTS MENTION AFTER 01Z TUESDAY FOR
NOW...TAPERING OFF AFTER 07Z TUESDAY. OTHERWISE...EXPECT VFR CIGS AND
GUSTY SOUTH WINDS FOR THIS AFTERNOON...BEFORE DIMINISHING AFTER
SUNSET.
SPECIFICS FOR KSTL...STILL HARD TO PIN DOWN EXACT COVERAGE AND
TIMING OF STORMS...LATEST HRRR MODEL INDICATING STORMS TO NOT MOVE
IN TIL AFTER 04Z TUESDAY...MAYBE EVEN LATER...BUT KEPT VCTS
MENTION AFTER 01Z TUESDAY FOR NOW AS WE COULD SEE STUFF FIRE UP
AHEAD OF MAIN ACTIVITY. STORMS TO TAPER OFF AFTER 07Z TUESDAY.
OTHERWISE...EXPECT VFR CIGS AND GUSTY SOUTH WINDS FOR THIS
AFTERNOON...BEFORE DIMINISHING AFTER SUNSET. ANOTHER ROUND OF
STORMS POSSIBLE AFTER 21Z TUESDAY...SO ADDED VCTS MENTION DURING
THIS PERIOD.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
818 PM MDT TUE MAY 21 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
MODEST UPDATE THIS EVENING. REDUCED OVERNIGHT TEMPERATURES SOME AS
THERE IS SOME CLEARING IN WESTERN PARTS OF THE CWA AND DEWPOINTS
ARE WELL BELOW GUIDANCE VALUES. HRRR AND NAM HINT AT SOME POSSIBLE
LIGHT SHOWERS OVER SOUTHERN PARTS OF THE CWA TONIGHT IN RESPONSE
TO A SUBTLE IMPROVEMENT IN THE UPPER FLOW...SO SPREAD THE SLIGHT
CHANCE FOR A SHOWERS IN THE FORECAST WESTWARD TO PHILLIPS COUNTY.
NEXT SEVERAL DAYS LOOK TO BE SOMEWHAT WINDY AS A STRONG SURFACE
LOW DEVELOPS OVER WESTERN WYOMING AND MONTANA AHEAD OF THE NEXT
LONG WAVE SYSTEM...AND THE LAKE WIND ADVISORY MIGHT BE NEEDED
THROUGH FRIDAY. MARTIN
PREVIOUS DISCUSSION...
AN UPPER LEVEL LOW OVER EASTERN SOUTH DAKOTA WILL
CONTINUE TO DRIVE WRAPAROUND LIGHT SHOWER ACTIVITY OVER THE
SOUTHEAST THIS EVENING. SHOWER ACTIVITY WILL QUICKLY TAPER OFF
AFTER MIDNIGHT AS THE UPPER LOW PUSHES TO THE EAST.
DRY AND WARM CONDITIONS WILL RULE ON WEDNESDAY AS UPPER RIDGING
DOMINATES AHEAD OF AN APPROACHING UPPER TROUGH OVER THE PACIFIC
NORTHWEST. GUSTY SOUTHEAST WINDS WILL ALSO PICK UP DURING THE LATE
MORNING IN RESPONSE TO THE APPROACHING LOW...NECESSITATING A LAKE
WIND ADVISORY THAT WILL LAST INTO LATE THURSDAY EVENING.
SOUTHERLY FLOW ALOFT ASSOCIATED WITH THE APPROACHING UPPER LOW
LOOKS TO BUILD INTO THE WESTERN ZONES BY WEDNESDAY EVENING.
DISTURBANCES IN THIS FLOW WILL CREATE DECENT CHANCES FOR SHOWERS
AND THUNDERSTORMS ACROSS THE WEST INTO THURSDAY. GILCHRIST
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE UPPER LEVEL RIDGE GETS PUSHED ASIDE THURSDAY NIGHT AND FRIDAY
BY A LOBE OFF THE STRONG PAC-NW CLOSED LOW SWINGING NORTH THROUGH
MONTANA. WEAK INSTABILITY DEVELOPS TO THE SOUTHWEST LATE THURSDAY
SO THE DISTURBANCE COULD GENERATE SCATTERED RAIN SHOWERS AND
ISOLATED THUNDER MAINLY IN THE WESTERN ZONES. A MORE DISTINCT COLD
FRONT WILL PUSH THROUGH THE AREA ON FRIDAY...BUT AGAIN...THE BEST
INSTABILITY AND MOISTURE REMAIN OUTSIDE NORTHEAST MONTANA...
ACCORDING TO THE GFS. THE TIMING IS DIFFERENT IN THE EC...WHICH COULD
BRING THE FRONT INTO THE AREA FRIDAY AFTERNOON WITH INSTABILITY.
WITH MODEL DIFFERENCES ON FRIDAY...WILL LEAVE POPS AS IS. MODEL
DIFFERENCES CONTINUE INTO SATURDAY. THERE COULD BE SHOWERS AND
THUNDER OR NOT...DEPENDING ON THE MODEL. SO AGAIN WILL LEAVE
ALONG. THERE IS AT LEAST THE POTENTIAL WITH THE GFS MODEL TO MATCH
UP A TEMPERATURE BOUNDARY WITH SOME VERY UNSTABLE CONDITIONS...
WHICH COULD LEAD TO SOME ENERGETIC THUNDERSTORMS. SUNDAY LOOKS
LIKE THE BEST DAY FOR TIMING AND LOCATION TO BRING ABOUT POSSIBLY
VERY ENERGETIC STORMS. THE GRIDS HANDLE THIS UNCERTAINTY WELL...SO
FEW CHANGE PAST DAY FOUR. SCT
PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS THURSDAY NIGHT
WITH A CLOSED UPPER TROUGH ACROSS THE WEST AND AN UPPER LEVEL
RIDGE ACROSS THE SOUTHERN U.S. THAT EXTENDS THROUGH THE PLAINS.
THIS PLACES NORTHEAST MONTANA IN DIFFLUENT SOUTHWEST FLOW ALOFT.
THE 00Z MODEL SUITE IS POINTING TO A ROBUST SHORTWAVE PUSHING
THROUGH THE FLOW WHICH COULD LEAD TO ENHANCED DYNAMIC LIFT ACROSS
PARTS OF THE CWA. THE 850MB LEVEL EASTERLY/SOUTHEASTERLY WINDS
WILL HELP TO PUMP IN LOW LEVEL MOISTURE...AND ALSO SUGGEST THE
PRESENCE OF A LOW LEVEL JET WHICH COULD HELP TO FORCE CONVECTION
IF THE OTHER DYNAMIC INGREDIENTS DISCUSSED COME TOGETHER
COINCIDENT LY. DECENT EQUIVALENT POTENTIAL TEMPERATURE RIDGE LOOKS
TO BE IN PLACE ACROSS THE CWA BY FRIDAY AFTERNOON WITH WARMING
TEMPERATURES OUT AHEAD OF THE TROUGH. THE MID LEVELS ALSO LOOK
PRETTY DRY. THIS LEADS TO THE CONCERN THAT SOME STORMS THAT
DEVELOP MAY PRODUCE HAIL. THE 00Z ECMWF FORECAST SOUNDINGS SHOW LI
BETWEEN -1 AND 1 ACROSS THE CWA AND TOTAL TOTALS IN THE UPPER 40S
AND NOT MUCH CAPE. NOTICE A NICE VEERING PROFILE IN THE ECMWF
FORECAST SOUNDINGS WITH ABOUT 40 KTS OF 0-6 KM SPEED SHEAR. THE
GFS SHOWS ACTUALLY HIGHER LIFTED INDEX VALUES AND IS LESS
SUGGESTIVE OF STRONG CONVECTION IN SHORT...THE INGREDIENTS ARE
THERE FOR GOOD THUNDERSTORM DEVELOPMENT BUT SOME PARAMETERS APPEAR
ONLY MARGINAL AND SO CONFIDENCE ON STRONG STORMS IS NOT YET THERE.
WILL NEED TO LOOK AT FUTURE MODEL RUNS FOR CONSISTENCY. TIMING OF
THE SHORTWAVE AS IT INTERSECTS THE THETA-E RIDGE WILL ALSO BE
KEY...RIGHT NOW IT APPEARS THE NORTHERN ZONES AND SOUTHERN
SASKATCHEWAN MAY BE IN THE BEST LOCATION FOR FRIDAY AFTERNOON FOR
CONVECTION INITIATION IF FOLLOWING THE EC GUIDANCE. ANY CONVECTION
SHOULD SLOWLY DWINDLE FRIDAY NIGHT WITH THE LOSS OF DAYTIME
HEATING.
ON SATURDAY...UPPER FLOW PATTERN MAINTAINS SOUTHWEST FLOW ALOFT
OVER THE CWA WITH RIDGE AXIS RUNNING FROM TEXAS...NORTHWESTWARD
THROUGH THE PLAINS AND INTO NE MT. THIS SHOULD ACTUALLY LEAD TO
WARMER TEMPERATURES WHICH COULD LEND TO ENHANCING THE POTENTIAL
FOR CONVECTION INITIATION. NICE UPPER LEVEL DIFFLUENCE IS NOTED
AND SOME OF THE FORECAST SOUNDINGS ARE CERTAINLY INDICATIVE OF
CONVECTIVE POTENTIAL. THERE IS ALSO SOME SUBTLE EMBEDDED SHORTWAVE
ENERGY THAT PUSHES THROUGH SHORTWAVE FLOW ALOFT...BUT NOTHING AS
IMPRESSIVE AS THE WAVE ON FRIDAY.
SUNDAY INTO SUNDAY NIGHT PRESENTLY LOOKS TO BE THE BEST POTENTIAL
FOR THUNDERSTORMS TO DEVELOP WHICH COULD BECOME STRONG IN NATURE.
THERE IS MUCH BETTER AGREEMENT IN BOTH THE ECMWF AND GFS WITH BOTH
FORECAST SOUNDINGS SHOWING LIFTED INDEX VALUES BETWEEN -5 AND -8
ACROSS THE CWA. THE GFS BUFKIT SOUNDING SHOWS AROUND 1500 J/KG OF
CAPE AND TOTAL TOTALS APPROACHING 60. THOUGH A NICE VEERING WIND
PROFILE EXISTS IN BOTH ECMWF/GFS SOUNDINGS... THOUGH WOULD LIKE
TO SEE MORE SPEED SHEAR IN THE SOUNDINGS. SHOULD ALSO POINT OUT
THAT FORECAST SOUNDINGS FROM BOTH MODELS ARE SHOWING PWATS OF OVER
AN INCH. WITH AGAIN DRY AIR PRESENT IN THE MID LEVELS...WOULD BE
CONCERNED ABOUT HAIL FORMATION WITH ANY STORMS. THERE IS AGAIN A
LOW LEVEL 850MB EASTERLY JET THAT FORMS...WHICH SHOULD HELP TO
PUMP IN LOW LEVEL MOISTURE. NICE THETA-E RIDGE AXIS OVER THE CWA
ALONG WITH A COUPLE OF SHORTWAVES THAT PASS OFF TO THE WEST COULD
ALSO HELP PROVIDE DECENT LIFT IF THE TIMING IS RIGHT...AND THAT
WILL BE THE KEY FOR DETERMINING THE OVERALL EXTENT OF THE
THUNDERSTORM POTENTIAL. OF ALL OF THE DAYS IN THE EXTENDED
PERIOD...THIS LOOKS TO BE THE ONE WITH THE BEST MODEL AGREEMENT
AND THE BEST IN TERMS OF VARIOUS INGREDIENTS COMING TOGETHER BOTH
DYNAMICALLY AND THERMODYNAMICALLY THAT ARE COINCIDENT WITH EACH
OTHER. WILL OF COURSE NEED TO WATCH FOR CONTINUITY IN THE MODEL
SOLUTIONS TO DETERMINE IF THIS CONTINUES. WILL ALSO NEED TO HONE
IN ON MESOSCALE DETAILS WHICH ARE DIFFICULT TO DETERMINE THIS FAR
IN ADVANCE. WHERE THESE INGREDIENTS COME TOGETHER...THE PRECISE
TIMING OF THE SHORTWAVE FEATURES...AND HOW EVERYTHING INTERACTS
WITH MESOSCALE PROCESSES WILL DETERMINE THE PRECISE EXTENT OF
CONVECTIVE POTENTIAL.
MONDAY AND BEYOND...NE MT IS EXPECTED TO REMAIN IN SOUTHWEST FLOW
ALOFT WITH THE ECMWF GUIDANCE SUGGESTING PERHAPS THE UPPER
PATTERN COULD BECOME MORE ZONAL LATE NEXT WEEK. THE GFS ON THE
OTHER HAND KEEPS THE OVERALL PATTERN ALOFT FROM THE SOUTHWEST. THIS
OVERALL PATTERN WOULD BE CONSIDERED FAVORABLE FOR A CONTINUED
POTENTIAL FOR CONVECTIVE SHOWERS AND THUNDERSTORMS TO DEVELOP
DEPENDING ON TIMING/TRACK OF SHORTWAVE FEATURES IN THE FLOW. MALIAWCO.
&&
.AVIATION...
PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
CANNOT RULE OUT SOME LOW END VFR/MARGINAL MVFR CEILINGS FOR A TIME
AT KSDY AND KGDV THROUGH TONIGHT. LOOK FOR PERSISTENT 10 TO 20 KT
EASTERLY WINDS THROUGH THE OVERNIGHT...INCREASING TO 15 TO 25 KT
ON WEDNESDAY. MALIAWCO
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 10 AM WEDNESDAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
915 AM MDT MON MAY 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
RAINFALL CONTINUES OVER THE EASTERN HALF OF THE CWA THIS MORNING.
MADE A FEW FURTHER ADJUSTMENTS TO THE WESTERN EDGE OF HIGH POPS
WITH EXPECTATION THAT RAIN WILL STAY TO THE EAST OF GLASGOW AND
JORDAN. SIMILAR ADJUSTMENTS ALSO MADE FOR TONIGHT WITH THE UPPER
LOW BEGINNING TO SHIFT EASTWARD. EBERT
6AM UPDATE...THE WESTERN PUSH OF RAIN LOOKS TO FALL SHORT OF
GLASGOW THEREFORE BACKED DOWN THE 100 POPS. PROTON
PREVIOUS SHORT TERM DISCUSSION...TODAY AND TONIGHT...A VERTICALLY
STACKED LOW PRESSURE SYSTEM SITUATED OVER THE DAKOTAS WILL
CONTINUE TO SIT AND SPIN. AS IT DOES...A SHIELD OF STRATIFORM RAIN
WILL CONTINUE TO RETROGRADE FROM EAST TO WEST THOUGH THE
DAY...BEFORE CRASHING BACK TO THE SOUTHEAST THIS AFTERNOON AND
EVENING AS THE LOW BEGINS TO TRANSLATE EASTWARD. DETERMINING THE
MAXIMUM EXTENT OF THE BACK EDGE OF THE RAINFALL SHIELD WILL
CONTINUE TO BE THE MAIN FORECAST CHALLENGE.
THE LATEST NAM HAD THE PRECIPITATION INITIALIZED A BIT FURTHER TO
THE EAST THAN RADAR OBSERVATIONS SHOWED. THUS...FEEL THE
PRECIPITATION SHIELD SHOULD MAKE IT A BIT FURTHER THAN THIS
SOLUTION IS SUGGESTING. THE 00Z ECMWF AND GFS HAVE A LITTLE BETTER
HANDLE ON IT. WILL ADMIT THAT THE HRRR HAS BEEN AN IMPRESSIVE
INFORMER AS IT CAUGHT ONTO THE IDEA THAT THE SHIELD WOULD STOP
RETROGRADING FOR A FEW HOURS OVERNIGHT BEFORE AGAIN PROCEEDING ITS
MARCH FURTHER WEST TOWARD MORNING AND THIS IS WHAT IS OCCURRING.
LENDING FURTHER SUPPORT TO THE GUIDANCE IS THE OBSERVATION OF
RECENT PRESSURE FALLS ACROSS THE CWA. PRESSURES ARE GENERALLY
FALLING BETWEEN 0.5 AND 1 MB PER HOUR FOR THE LAST FEW HOURS.
THEREFORE...WILL FEEL COMFORTABLE WITH A BLEND OF THE
ECMWF/GFS/HRRR MODEL SOLUTIONS FOR DETERMINING A BEST GUESS AS TO
WHERE THE BACK EDGE WILL REACH BEFORE IT BEGINS TO PUSH BACK TO
THE SOUTHEAST. THIS BRINGS IT TO A LINE FROM ABOUT OPHEIM...EXTENDING
SOUTH THROUGH JUST WEST OF GLASGOW...TO THE JORDAN AREA. TO THE
EAST OF THIS LINE...THERE IS A DECENT CHANCE AT A NICE WETTING
RAIN THROUGH TONIGHT. IN FACT...WOULD NOT BE SURPRISED IF SOME
AREAS SEE ONE TO TWO INCHES OF RAINFALL ACCUMULATION BY THE END OF
TONIGHT AND INCLUDED A MENTION OF HEAVY RAIN IN SOME OF THE
EASTERN ZONES THROUGH THE MORNING. TO THE WEST OF THIS LINE...RAIN
CHANCES WILL ONLY BE SHOWERY IN NATURE WITH A FEW HUNDREDTHS OF AN
INCH OF ACCUMULATION THE ABSOLUTE MOST THAT WOULD OCCUR. PRECISE
RAINFALL AMOUNTS WILL DEPEND UPON THE PRECISE LOCATION OF WHERE
THE BACK EDGE OF THIS RAIN SHIELD WINDS UP...AS WELL AS SOME FINER
MESOSCALE DETAILS THAT ARE DIFFICULT TO DETERMINE WITH MUCH
CONFIDENCE. TEMPERATURES ARE KEPT AROUND OR JUST BELOW SEASONAL
NORMALS DUE TO THE PRESENCE OF THE LINGERING UPPER TROUGH.
THE OTHER CONCERN TODAY WILL BE STRONG GUSTY WINDS DUE TO A SHARP
PRESSURE GRADIENT IN ASSOCIATION WITH THE SURFACE LOW ACROSS THE
DAKOTAS. AM EXPECTING THAT THE TIGHT PACKING OF THE ISOBARS COULD
SUPPORT NORTHERLY WINDS ON THE ORDER OF 20 TO 30 MPH WITH SOME
GUSTS EXCEEDING 40 MPH THIS AFTERNOON AND EVENING. WILL HOIST A
LAKE WIND ADVISORY FROM NOON UNTIL 9PM DUE TO THIS CONCERN. THIS
MAY ALSO LEAD TO WIND DRIVEN RAINS IN SOME LOCATIONS WHICH COULD
POSE AS HAZARDS TO TRAVELERS AND PEDESTRIANS ALIKE.
TONIGHT THROUGH WEDNESDAY...THE LOW PRESSURE SYSTEM OVER THE
DAKOTAS VERY GRADUALLY TRANSLATES EASTWARD...SO CONTINUED TO TREND
POPS DOWN AND HAVE PRECIPITATION SHUTTING OFF FROM WEST TO EAST.
WILL LEAVE ONLY A SLIGHT CHANCE OF RAIN SHOWERS IN THE EXTREME SE
ZONES BY LATE TUESDAY NIGHT. ON WEDNESDAY...ANOTHER UPPER TROUGH
WITH CLOSED LOW MOVES INTO THE PACIFIC NORTHWEST AS IT DOES
SO...DIFFLUENT SOUTHWEST FLOW ALOFT IS EXPECTED TO DEVELOP ACROSS
THE CWA. THIS MAY LEAD TO CONVECTIVE SHOWERS ON WEDNESDAY...MAINLY
ACROSS THE SW ZONES. SOME OF THE SOUNDINGS IN THE NAM BUFKIT JUST
WEST OF THE CWA ARE SHOWING TOTAL TOTALS APPROACHING 50 AND LI
BECOMING NEGATIVE. DID NOT INSERT A MENTION OF THUNDER JUST YET DUE TO THE
FACT THAT THE PRIMARY FOCUS WAS ON THE CURRENT RAINFALL SITUATION
AND LAKE WIND POTENTIAL. HOWEVER...FUTURE SHIFTS MAY WANT TO
EVALUATE THE POTENTIAL FOR ANY CONVECTIVE INITIATION TOWARD THE
MIDDLE OF THE WEEK. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED FEATURES MORE SOUTHWEST FLOW THROUGH THE PERIOD. MOST
DAYS SLIGHT CHANCES OF THUNDERSTORMS SLIDING OFF THE CENTRAL
MONTANA MOUNTAINS INTO THE PLAINS FOR HIGHER POPS WEST AND LOW
POPS EAST. FOR THE WEEKEND THE UPPER LOW BREAKS A GOOD WAVE OFF
AND DRIVES IT THROUGH NORTHEAST MONTANA FOR A BETTER CHANCE OF
THUNDERSTORMS THEREFORE BUMPED UP POPS A TAD FOR THOSE PERIODS.
TEMPERATURES WILL HOLD IN NEAR NORMAL THROUGH THE PERIOD.
MODEL TRENDS ARE SHOWING LOWERING HEIGHTS ON THE GFS FOR NORTHEAST
MONTANA WHICH LEADS TO THE UPPER LOW MOVING TOWARDS THE EAST. IF
THE TREND CONTINUES THEN LIKELY POPS ARE A GOOD BET FOR THE
WEEKEND WITH ELEVATED CONFIDENCE. RMOP/ENSEMBLES ARE SHOWING THAT
ITS A GOOD BET THAT AT SOME POINT THIS UPCOMING WEEKEND FOR A
STRONG THUNDERSTORM EVENT ACROSS EASTERN MONTANA. PROTON
&&
.AVIATION...
MVFR VISIBILITY FROM RAIN WITH MVFR/IFR CEILINGS FOR THE EASTERN
AREAS INCLUDING KSDY AND KGDV THROUGH THE PERIOD AS THEY ARE
CLOSER TO THE LOW OVER SOUTHEASTERN NORTH DAKOTA WHICH IS WRAPPING
AROUND MOISTURE INTO THE LOWER YELLOWSTONE RIVER VALLEY. THIS
TREND LOOKS TO CONTINUE THROUGH THE PERIOD.
VFR FOR WESTERN AREAS INCLUDING KGGW AND KOLF THROUGH THE PERIOD
THE MVFR/IFR CEILING SHIELD LOOKS TO STAY JUST OFF TO THE EAST.
FOR NOW WILL STAY WITH VFR CEILINGS.
WIND WILL BE MORE OF AN ISSUE FOR THE EASTERN SITES WITH THE WINDS
STAYING UP ABOVE 20 KNOTS THROUGH THE END OF THE TAF PERIOD.
PROTON/SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
553 AM MDT MON MAY 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
6AM UPDATE...THE WESTERN PUSH OF RAIN LOOKS TO FALL SHORT OF
GLASGOW THEREFORE BACKED DOWN THE 100 POPS. PROTON
TODAY AND TONIGHT...A VERTICALLY STACKED LOW PRESSURE SYSTEM
SITUATED OVER THE DAKOTAS WILL CONTINUE TO SIT AND SPIN. AS IT
DOES...A SHIELD OF STRATIFORM RAIN WILL CONTINUE TO RETROGRADE
FROM EAST TO WEST THOUGH THE DAY...BEFORE CRASHING BACK TO THE
SOUTHEAST THIS AFTERNOON AND EVENING AS THE LOW BEGINS TO
TRANSLATE EASTWARD. DETERMINING THE MAXIMUM EXTENT OF THE BACK
EDGE OF THE RAINFALL SHIELD WILL CONTINUE TO BE THE MAIN FORECAST
CHALLENGE.
THE LATEST NAM HAD THE PRECIPITATION INITIALIZED A BIT FURTHER TO
THE EAST THAN RADAR OBSERVATIONS SHOWED. THUS...FEEL THE
PRECIPITATION SHIELD SHOULD MAKE IT A BIT FURTHER THAN THIS
SOLUTION IS SUGGESTING. THE 00Z ECMWF AND GFS HAVE A LITTLE BETTER
HANDLE ON IT. WILL ADMIT THAT THE HRRR HAS BEEN AN IMPRESSIVE
INFORMER AS IT CAUGHT ONTO THE IDEA THAT THE SHIELD WOULD STOP
RETROGRADING FOR A FEW HOURS OVERNIGHT BEFORE AGAIN PROCEEDING ITS
MARCH FURTHER WEST TOWARD MORNING AND THIS IS WHAT IS OCCURRING.
LENDING FURTHER SUPPORT TO THE GUIDANCE IS THE OBSERVATION OF
RECENT PRESSURE FALLS ACROSS THE CWA. PRESSURES ARE GENERALLY
FALLING BETWEEN 0.5 AND 1 MB PER HOUR FOR THE LAST FEW HOURS.
THEREFORE...WILL FEEL COMFORTABLE WITH A BLEND OF THE
ECMWF/GFS/HRRR MODEL SOLUTIONS FOR DETERMINING A BEST GUESS AS TO
WHERE THE BACK EDGE WILL REACH BEFORE IT BEGINS TO PUSH BACK TO
THE SOUTHEAST. THIS BRINGS IT TO A LINE FROM ABOUT OPHEIM...EXTENDING
SOUTH THROUGH JUST WEST OF GLASGOW...TO THE JORDAN AREA. TO THE
EAST OF THIS LINE...THERE IS A DECENT CHANCE AT A NICE WETTING
RAIN THROUGH TONIGHT. IN FACT...WOULD NOT BE SURPRISED IF SOME
AREAS SEE ONE TO TWO INCHES OF RAINFALL ACCUMULATION BY THE END OF
TONIGHT AND INCLUDED A MENTION OF HEAVY RAIN IN SOME OF THE
EASTERN ZONES THROUGH THE MORNING. TO THE WEST OF THIS LINE...RAIN
CHANCES WILL ONLY BE SHOWERY IN NATURE WITH A FEW HUNDREDTHS OF AN
INCH OF ACCUMULATION THE ABSOLUTE MOST THAT WOULD OCCUR. PRECISE
RAINFALL AMOUNTS WILL DEPEND UPON THE PRECISE LOCATION OF WHERE
THE BACK EDGE OF THIS RAIN SHIELD WINDS UP...AS WELL AS SOME FINER
MESOSCALE DETAILS THAT ARE DIFFICULT TO DETERMINE WITH MUCH
CONFIDENCE. TEMPERATURES ARE KEPT AROUND OR JUST BELOW SEASONAL
NORMALS DUE TO THE PRESENCE OF THE LINGERING UPPER TROUGH.
THE OTHER CONCERN TODAY WILL BE STRONG GUSTY WINDS DUE TO A SHARP
PRESSURE GRADIENT IN ASSOCIATION WITH THE SURFACE LOW ACROSS THE
DAKOTAS. AM EXPECTING THAT THE TIGHT PACKING OF THE ISOBARS COULD
SUPPORT NORTHERLY WINDS ON THE ORDER OF 20 TO 30 MPH WITH SOME
GUSTS EXCEEDING 40 MPH THIS AFTERNOON AND EVENING. WILL HOIST A
LAKE WIND ADVISORY FROM NOON UNTIL 9PM DUE TO THIS CONCERN. THIS
MAY ALSO LEAD TO WIND DRIVEN RAINS IN SOME LOCATIONS WHICH COULD
POSE AS HAZARDS TO TRAVELERS AND PEDESTRIANS ALIKE.
TONIGHT THROUGH WEDNESDAY...THE LOW PRESSURE SYSTEM OVER THE
DAKOTAS VERY GRADUALLY TRANSLATES EASTWARD...SO CONTINUED TO TREND
POPS DOWN AND HAVE PRECIPITATION SHUTTING OFF FROM WEST TO EAST.
WILL LEAVE ONLY A SLIGHT CHANCE OF RAIN SHOWERS IN THE EXTREME SE
ZONES BY LATE TUESDAY NIGHT. ON WEDNESDAY...ANOTHER UPPER TROUGH
WITH CLOSED LOW MOVES INTO THE PACIFIC NORTHWEST AS IT DOES
SO...DIFFLUENT SOUTHWEST FLOW ALOFT IS EXPECTED TO DEVELOP ACROSS
THE CWA. THIS MAY LEAD TO CONVECTIVE SHOWERS ON WEDNESDAY...MAINLY
ACROSS THE SW ZONES. SOME OF THE SOUNDINGS IN THE NAM BUFKIT JUST
WEST OF THE CWA ARE SHOWING TOTAL TOTALS APPROACHING 50 AND LI
BECOMING NEGATIVE. DID NOT INSERT A MENTION OF THUNDER JUST YET DUE TO THE
FACT THAT THE PRIMARY FOCUS WAS ON THE CURRENT RAINFALL SITUATION
AND LAKE WIND POTENTIAL. HOWEVER...FUTURE SHIFTS MAY WANT TO
EVALUATE THE POTENTIAL FOR ANY CONVECTIVE INITIATION TOWARD THE
MIDDLE OF THE WEEK. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED FEATURES MORE SOUTHWEST FLOW THROUGH THE PERIOD. MOST
DAYS SLIGHT CHANCES OF THUNDERSTORMS SLIDING OFF THE CENTRAL
MONTANA MOUNTAINS INTO THE PLAINS FOR HIGHER POPS WEST AND LOW
POPS EAST. FOR THE WEEKEND THE UPPER LOW BREAKS A GOOD WAVE OFF
AND DRIVES IT THROUGH NORTHEAST MONTANA FOR A BETTER CHANCE OF
THUNDERSTORMS THEREFORE BUMPED UP POPS A TAD FOR THOSE PERIODS.
TEMPERATURES WILL HOLD IN NEAR NORMAL THROUGH THE PERIOD.
MODEL TRENDS ARE SHOWING LOWERING HEIGHTS ON THE GFS FOR NORTHEAST
MONTANA WHICH LEADS TO THE UPPER LOW MOVING TOWARDS THE EAST. IF
THE TREND CONTINUES THEN LIKELY POPS ARE A GOOD BET FOR THE
WEEKEND WITH ELEVATED CONFIDENCE. RMOP/ENSEMBLES ARE SHOWING THAT
ITS A GOOD BET THAT AT SOME POINT THIS UPCOMING WEEKEND FOR A
STRONG THUNDERSTORM EVENT ACROSS EASTERN MONTANA. PROTON
&&
.AVIATION...
MVFR FOR THE EASTERN AREAS INCLUDING KSDY AND KGDV THROUGH THE
PERIOD AS THEY ARE CLOSER TO THE LOW OVER SOUTHEASTERN NORTH
DAKOTA WHICH IS WRAPPING AROUND MOISTURE INTO THE LOWER YELLOWSTONE
RIVER VALLEY. THIS TREND LOOKS TO CONTINUE THROUGH THE PERIOD.
VFR FOR WESTERN AREAS INCLUDING KGGW AND KOLF THROUGH THE PERIOD
AS THE MVFR CEILING SHIELD LOOKS TO STAY JUST OFF TO THE EAST. FOR
NOW WILL STAY WITH VFR CEILINGS.
WIND WILL BE MORE OF AN ISSUE FOR THE EASTERN SITES WITH THE WINDS
STAYING UP ABOVE 20 KNOTS THROUGH THE END OF THE TAF PERIOD. PROTON
&&
.HYDROLOGY...
THE NEXT COUPLE OF DAYS WILL CONTINUE TO BE VERY WET AS NORTHEAST
MONTANA REMAINS UNDER THE INFLUENCE OF A LARGE UPPER TROUGH AND
VERTICALLY STACKED LOW PRESSURE SYSTEM SITUATED ACROSS THE
DAKOTAS. A LARGE AREA OF STRATIFORM RAIN WILL AFFECT ESPECIALLY EASTERN
AREAS OF THE FORECAST AREA. SOME LOCATIONS COULD PICK UP BETWEEN
ONE AND TWO INCHES OF RAINFALL BY TUESDAY MORNING...ESPECIALLY IN
EASTERN ROOSEVELT AND RICHLAND COUNTIES WHERE THE STEADIEST RAIN
IS EXPECTED.
MOST OF THE BASINS IN NORTHEAST MONTANA WILL BE ABLE TO
ACCOMMODATE THIS AMOUNT OF MOISTURE. HOWEVER THERE IS SOME
CONCERN FOR RAPIDLY RISING STREAMS...FIELD FLOODING AND LOCALIZED
FLOODING IN TOWNS AS THE EVENT PERSISTS. SOME MINOR FLOODING MAY
BECOME AN ISSUE...ESPECIALLY FOR THE AREAS FROM WOLF POINT TO
CIRCLE AND EASTWARD INTO NORTH DAKOTA WHERE THE POTENTIAL FOR RAIN
IS THE HIGHEST.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
402 AM MDT MON MAY 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
TODAY AND TONIGHT...A VERTICALLY STACKED LOW PRESSURE SYSTEM
SITUATED OVER THE DAKOTAS WILL CONTINUE TO SIT AND SPIN. AS IT
DOES...A SHIELD OF STRATIFORM RAIN WILL CONTINUE TO RETROGRADE
FROM EAST TO WEST THOUGH THE DAY...BEFORE CRASHING BACK TO THE
SOUTHEAST THIS AFTERNOON AND EVENING AS THE LOW BEGINS TO
TRANSLATE EASTWARD. DETERMINING THE MAXIMUM EXTENT OF THE BACK
EDGE OF THE RAINFALL SHIELD WILL CONTINUE TO BE THE MAIN FORECAST
CHALLENGE.
THE LATEST NAM HAD THE PRECIPITATION INITIALIZED A BIT FURTHER TO
THE EAST THAN RADAR OBSERVATIONS SHOWED. THUS...FEEL THE
PRECIPITATION SHIELD SHOULD MAKE IT A BIT FURTHER THAN THIS
SOLUTION IS SUGGESTING. THE 00Z ECMWF AND GFS HAVE A LITTLE BETTER
HANDLE ON IT. WILL ADMIT THAT THE HRRR HAS BEEN AN IMPRESSIVE
INFORMER AS IT CAUGHT ONTO THE IDEA THAT THE SHIELD WOULD STOP
RETROGRADING FOR A FEW HOURS OVERNIGHT BEFORE AGAIN PROCEEDING ITS
MARCH FURTHER WEST TOWARD MORNING AND THIS IS WHAT IS OCCURRING.
LENDING FURTHER SUPPORT TO THE GUIDANCE IS THE OBSERVATION OF
RECENT PRESSURE FALLS ACROSS THE CWA. PRESSURES ARE GENERALLY
FALLING BETWEEN 0.5 AND 1 MB PER HOUR FOR THE LAST FEW HOURS.
THEREFORE...WILL FEEL COMFORTABLE WITH A BLEND OF THE
ECMWF/GFS/HRRR MODEL SOLUTIONS FOR DETERMINING A BEST GUESS AS TO
WHERE THE BACK EDGE WILL REACH BEFORE IT BEGINS TO PUSH BACK TO
THE SOUTHEAST. THIS BRINGS IT TO A LINE FROM ABOUT OPHEIM...EXTENDING
SOUTH THROUGH JUST WEST OF GLASGOW...TO THE JORDAN AREA. TO THE
EAST OF THIS LINE...THERE IS A DECENT CHANCE AT A NICE WETTING
RAIN THROUGH TONIGHT. IN FACT...WOULD NOT BE SURPRISED IF SOME
AREAS SEE ONE TO TWO INCHES OF RAINFALL ACCUMULATION BY THE END OF
TONIGHT AND INCLUDED A MENTION OF HEAVY RAIN IN SOME OF THE
EASTERN ZONES THROUGH THE MORNING. TO THE WEST OF THIS LINE...RAIN
CHANCES WILL ONLY BE SHOWERY IN NATURE WITH A FEW HUNDREDTHS OF AN
INCH OF ACCUMULATION THE ABSOLUTE MOST THAT WOULD OCCUR. PRECISE
RAINFALL AMOUNTS WILL DEPEND UPON THE PRECISE LOCATION OF WHERE
THE BACK EDGE OF THIS RAIN SHIELD WINDS UP...AS WELL AS SOME FINER
MESOSCALE DETAILS THAT ARE DIFFICULT TO DETERMINE WITH MUCH
CONFIDENCE. TEMPERATURES ARE KEPT AROUND OR JUST BELOW SEASONAL
NORMALS DUE TO THE PRESENCE OF THE LINGERING UPPER TROUGH.
THE OTHER CONCERN TODAY WILL BE STRONG GUSTY WINDS DUE TO A SHARP
PRESSURE GRADIENT IN ASSOCIATION WITH THE SURFACE LOW ACROSS THE
DAKOTAS. AM EXPECTING THAT THE TIGHT PACKING OF THE ISOBARS COULD
SUPPORT NORTHERLY WINDS ON THE ORDER OF 20 TO 30 MPH WITH SOME
GUSTS EXCEEDING 40 MPH THIS AFTERNOON AND EVENING. WILL HOIST A
LAKE WIND ADVISORY FROM NOON UNTIL 9PM DUE TO THIS CONCERN. THIS
MAY ALSO LEAD TO WIND DRIVEN RAINS IN SOME LOCATIONS WHICH COULD
POSE AS HAZARDS TO TRAVELERS AND PEDESTRIANS ALIKE.
TONIGHT THROUGH WEDNESDAY...THE LOW PRESSURE SYSTEM OVER THE
DAKOTAS VERY GRADUALLY TRANSLATES EASTWARD...SO CONTINUED TO TREND
POPS DOWN AND HAVE PRECIPITATION SHUTTING OFF FROM WEST TO EAST.
WILL LEAVE ONLY A SLIGHT CHANCE OF RAIN SHOWERS IN THE EXTREME SE
ZONES BY LATE TUESDAY NIGHT. ON WEDNESDAY...ANOTHER UPPER TROUGH
WITH CLOSED LOW MOVES INTO THE PACIFIC NORTHWEST AS IT DOES
SO...DIFFLUENT SOUTHWEST FLOW ALOFT IS EXPECTED TO DEVELOP ACROSS
THE CWA. THIS MAY LEAD TO CONVECTIVE SHOWERS ON WEDNESDAY...MAINLY
ACROSS THE SW ZONES. SOME OF THE SOUNDINGS IN THE NAM BUFKIT JUST
WEST OF THE CWA ARE SHOWING TOTAL TOTALS APPROACHING 50 AND LI
BECOMING NEGATIVE. DID NOT INSERT A MENTION OF THUNDER JUST YET DUE TO THE
FACT THAT THE PRIMARY FOCUS WAS ON THE CURRENT RAINFALL SITUATION
AND LAKE WIND POTENTIAL. HOWEVER...FUTURE SHIFTS MAY WANT TO
EVALUATE THE POTENTIAL FOR ANY CONVECTIVE INITIATION TOWARD THE
MIDDLE OF THE WEEK. MALIAWCO
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED FEATURES MORE SOUTHWEST FLOW THROUGH THE PERIOD. MOST
DAYS SLIGHT CHANCES OF THUNDERSTORMS SLIDING OFF THE CENTRAL
MONTANA MOUNTAINS INTO THE PLAINS FOR HIGHER POPS WEST AND LOW
POPS EAST. FOR THE WEEKEND THE UPPER LOW BREAKS A GOOD WAVE OFF
AND DRIVES IT THROUGH NORTHEAST MONTANA FOR A BETTER CHANCE OF
THUNDERSTORMS THEREFORE BUMPED UP POPS A TAD FOR THOSE PERIODS.
TEMPERATURES WILL HOLD IN NEAR NORMAL THROUGH THE PERIOD.
MODEL TRENDS ARE SHOWING LOWERING HEIGHTS ON THE GFS FOR NORTHEAST
MONTANA WHICH LEADS TO THE UPPER LOW MOVING TOWARDS THE EAST. IF
THE TREND CONTINUES THEN LIKELY POPS ARE A GOOD BET FOR THE
WEEKEND WITH ELEVATED CONFIDENCE. RMOP/ENSEMBLES ARE SHOWING THAT
ITS A GOOD BET THAT AT SOME POINT THIS UPCOMING WEEKEND FOR A
STRONG THUNDERSTORM EVENT ACROSS EASTERN MONTANA. PROTON
&&
.AVIATION...
MVFR FOR THE EASTERN AREAS INCLUDING KSDY AND KGDV THROUGH THE
PERIOD AS THEY ARE CLOSER TO THE LOW OVER SOUTHEASTERN NORTH
DAKOTA WHICH IS WRAPPING AROUND MOISTURE INTO THE LOWER YELLOWSTONE
RIVER VALLEY. THIS TREND LOOKS TO CONTINUE THROUGH THE PERIOD.
VFR FOR WESTERN AREAS INCLUDING KGGW AND KOLF THROUGH THE PERIOD
AS THE MVFR CEILING SHIELD LOOKS TO STAY JUST OFF TO THE EAST. FOR
NOW WILL STAY WITH VFR CEILINGS.
WIND WILL BE MORE OF AN ISSUE FOR THE EASTERN SITES WITH THE WINDS
STAYING UP ABOVE 20 KNOTS THROUGH THE END OF THE TAF PERIOD. PROTON
&&
.HYDROLOGY...
THE NEXT COUPLE OF DAYS WILL CONTINUE TO BE VERY WET AS NORTHEAST
MONTANA REMAINS UNDER THE INFLUENCE OF A LARGE UPPER TROUGH AND
VERTICALLY STACKED LOW PRESSURE SYSTEM SITUATED ACROSS THE
DAKOTAS. A LARGE AREA OF STRATIFORM RAIN WILL AFFECT ESPECIALLY EASTERN
AREAS OF THE FORECAST AREA. SOME LOCATIONS COULD PICK UP BETWEEN
ONE AND TWO INCHES OF RAINFALL BY TUESDAY MORNING...ESPECIALLY IN
EASTERN ROOSEVELT AND RICHLAND COUNTIES WHERE THE STEADIEST RAIN
IS EXPECTED.
MOST OF THE BASINS IN NORTHEAST MONTANA WILL BE ABLE TO
ACCOMMODATE THIS AMOUNT OF MOISTURE. HOWEVER THERE IS SOME
CONCERN FOR RAPIDLY RISING STREAMS...FIELD FLOODING AND LOCALIZED
FLOODING IN TOWNS AS THE EVENT PERSISTS. SOME MINOR FLOODING MAY
BECOME AN ISSUE...ESPECIALLY FOR THE AREAS FROM WOLF POINT TO
CIRCLE AND EASTWARD INTO NORTH DAKOTA WHERE THE POTENTIAL FOR RAIN
IS THE HIGHEST.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1227 PM CDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT MON MAY 20 2013
TODAY AND TONIGHT...
THE BAND OF SHOWERS AND RAIN ACROSS THE SOUTHWESTERN AND NORTHEAST
PORTIONS OF THE FCST AREA SHOULD EXIT SOUTH AND EAST BY
DAYLIGHT...MID MORNING AT THE LATEST. THE RAP...HRRR AND NAM THEN
DROP A SECOND BATCH OF RAIN AND SHOWERS SOUTH OUT OF WRN SD THIS
MORNING AND THIS AFTN. THIS AREA OF RAIN SHOULD PRESUMABLY CONTINUE
MOVING SOUTH THIS EVENING WITH A WEAKENING TREND.
THUNDERSTORM CHANCES ARE VERY LOW IF THE RAP AND NAM ARE CORRECT.
NEITHER INDICATE ANY ELEVATED INSTABILITY FROM 750 MB ON UP AND THE
SFC BASED NAM THUNDERSTORM PROBABILITY CHART IS 10 PERCENT OR LESS.
WINDS INCREASE TO WIND ADVISORY CRITERIA TODAY ACROSS PARTS OF THE
WEST WITH H850 WINDS INCREASING TO 45 KT. THE MET AND MAV GUIDANCE
WERE THE BASIS FOR THE FORECAST WIND SPEEDS WHICH INCREASE TO AROUND
30 MPH. WINDS SHOULD SLACKEN THIS EVENING AS LOW PRESSURE ACROSS THE
NRN PLAINS BEGINS TO FILL.
TEMPERATURES ARE A BLEND OF NAM...GEMREG AND ECM PLUS BIAS
CORRECTION FOR HIGHS AND THE 50S AND 60S TODAY WITH LOWS IN THE 40S
AND 50S TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM CDT MON MAY 20 2013
ON TUESDAY...
THE UPPER LOW IS FORECAST TO MOVE FROM CENTRAL INTO FAR SOUTHEAST
SOUTH DAKOTA. A LOBE ON THE WESTERN PERIPHERY OF THE LOW WILL
ROTATE THROUGH WESTERN NEBRASKA WITH A CHANCE FOR SHOWERS MAINLY
ACROSS NORTH CENTRAL NEBRASKA. DESPITE A MOIST PROFILE...LIFT WILL
BE VERY WEAK...MAINLY IN THE H850-H7 LAYER. HAVE LOWERED POPS TO
NEAR 50 PERCENT FOR SHERIDAN AND WRN CHERRY AND FROM 30-40 PERCENT
ACROSS THE REMAINDER OF NCTRL WITH SLIGHT CHANCE POPS IN SWRN NEBR
IN THE MORNING. REGARDING WINDS...STRONGEST WINDS FORECAST FROM
THE EASTERN PANHANDLE INTO SOUTHWEST NEBR...WHERE SUSTAINED WIND
WILL REACH NEAR 25KT AND GUST NEAR 35KT THROUGH THE DAY. THIS IS
DUE TO DEEP MIX DOWN POTENTIAL WHERE UNIDIRECTIONAL NORTHWEST
WINDS EXTEND FROM THE SFC TO ABOVE 400 MB. THEREFORE A WIND
ADVISORY MAY BE NEEDED IF FORECAST WINDS CONTINUE TO LOOK SIMILAR.
HIGHS WILL BE AFFECTED MOST BY CLOUD COVER/SHOWERS FROM 55-60
NCTRL TO NEAR 70 FAR SW.
TUESDAY NIGHT AND WEDNESDAY...
AS UPPER LOW MOVES SLOWLY EAST ACROSS NRN IOWA...STILL SUPPORTIVE
OF A FEW SHOWERS TUES NIGHT NORTH CENTRAL AND NORTHEAST WEDNESDAY
AS WRAPAROUND MOISTURE STILL PRESENT. AN UPPER RIDGE WILL ALSO
BUILD INTO THE CNTRL ROCKIES WEDNESDAY IN RESPONSE TO A
SUBSTANTIAL CLOSED LOW DIGGING INTO THE PAC NW. CLEARING SKIES IN
THE WEST AND WEAK HIGH PRESSURE BUILDING IN TO BRING COOLER LOWS
FROM THE UPPER 30S TO LOWER 40S WEST TO NEAR 45 EAST. ONLY A MINOR
CHANGE TO HIGHS WEDNESDAY FROM 62-66 NCTRL TO 67-73 SOUTH.
THURSDAY THROUGH SUNDAY...
AN UNSETTLED WEATHER PATTERN WILL SET UP AS AN UPPER TROUGH
REMAINS ACROSS THE WESTERN U.S AND A RIDGE ACROSS THE CENTRAL
CONUS. ABUNDANT LOW LEVEL MOISTURE WILL INCREASE WITH H85
DEWPOINTS FROM 12-15C AT TIMES FRIDAY THROUGH SUNDAY. THE PRESENCE
OF A NOCTURNAL LOW LEVEL JET WILL ALSO ALLOW FOR THUNDERSTORMS TO
POSSIBLY DEVELOP INTO AN MCS ACROSS THE REGION EACH NIGHT. HIGHS
FROM THE UPPER 60S TO LOWER 70S THU-FRI WILL WARM TO THE UPPER 70S
TO LOWER 80S SAT-SUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1227 PM CDT MON MAY 20 2013
AN UPPER LEVEL LOW WILL REMAIN NEARLY STATIONARY ACROSS SOUTH
DAKOTA... KEEPING LOW CEILINGS... SHOWERS... AND WIDESPREAD MVFR
CONDITIONS ACROSS NORTH CENTRAL NEBRASKA. FARTHER SOUTH... DRIER
AIR WILL KEEP CEILINGS ABOVE MVFR FOR THE MOST PART WITH SCATTERED
SHOWERS POSSIBLE. CONDITIONS SHOULD REMAIN SIMILAR THROUGH THE
NIGHT WITH PERHAPS CEILINGS LIFTING TO JUST ABOVE MVFR CRITERIA
ACROSS NORTH CENTRAL NEBRASKA... AS SOMEWHAT DRIER AIR BEGINS TO
FILTER INTO THE LOWER LEVELS OF THE ATMOSPHERE. SURFACE WINDS WILL
BE GUSTY THROUGH THE AFTERNOON AND DIMINISH SOMEWHAT TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR NEZ004-022-023-035-
056>058.
&&
$$
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1216 PM CDT MON MAY 20 2013
.UPDATE...
FORECAST IS GENERALLY ON TRACK FOR THIS AFTERNOON. SURFACE-BASED
CAPE VALUES ARE STILL EXPECTED INTO THE 500-1000 J/KG RANGE LATE
TODAY IN THE SOUTHEAST HALF OF THE CWA...ALONG WITH MODERATE
EFFECTIVE BULK SHEAR AROUND 40KT. A SURFACE TROUGH WAS NOTED IN
CENTRAL NEBRASKA...AND RAP FORECAST SUGGEST THIS WILL BE SWEEPING
ACROSS EASTERN NEBRASKA BEFORE 00Z. SO THE COMBINATION OF WEAK
INSTABILITY WITH MODERATE SHEAR AND A FOCUSING MECHANISM SHOULD
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS DRIVEN BY AFTERNOON
HEATING. SMALL HAIL AND GUSTY WINDS ARE POSSIBLE GIVEN LAPSE RATES
APPROACHING 8C IN OUR FAR SOUTHEAST AND MODEST TEMP-DEW POINT
DEPRESSIONS.
DERGAN
&&
.AVIATION...18Z TAFS FOR KOFK...KLNK AND KOMA.
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY MORNING.
SCATTERED TO BROKEN CUMULUS NEAR FL050 IS FORECAST THROUGH THE
AFTERNOON. A FEW SHOWERS OR ISOLATED THUNDERSTORMS COULD DEVELOP
BRINGING MVFR CONDITIONS TO SOME AREAS. HOWEVER CHANCES AT TAF
SITES ARE RATHER SLIM. PRECIPITATION SHOULD DISSIPATE WITH THE
SETTING SUN...THEN CIGS NEAR FL040 WILL OVERSPREAD EASTERN
NEBRASKA FROM THE NORTH. SOME MVFR CIGS ARE POSSIBLE IN NORTHEAST
NEBRASKA NEAR KOFK AFTER 06Z...BUT HAVE LEFT OUT OF TAF FORECAST
AT THE MOMENT.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 323 AM CDT MON MAY 20 2013/
DISCUSSION...
THE UPPER LEVEL LOW CURRENTLY CENTERED OVER NE NEB AND ERN SD WILL
CONTINUE TO BE THE MAIN FORECAST ISSUE THROUGH THE SHORT TERM.
BROAD Q-G FORCING FOR ASCENT UNDER THE UPPER LEVEL LOW WAS
LEADING TO SCATTERED SHOWERS OVER CENTRAL AND NE NEB EARLY THIS
MORNING. THIS SHOULD CONT IN NE NEB WITH MOST OF THE CENTRAL AND
SOUTHERN CWA DRY THIS MORNING. SOME SUN IS EXPECTED TODAY OVER
THIS AREA OF THE CWA /SW IA AND SE NEB/ THAT WILL STEEPEN LOW
LEVEL LAPSE RATES. GIVEN THE RESIDUAL LOW LEVEL MOISTURE IN PLACE
ACROSS THIS AREA AND THE COLD MID LEVEL TEMPERATURES UNDER THE
UPPER LEVEL LOW...THE ATMOSPHERE SHOULD BECOME WEAKLY UNSTABLE
THIS AFTERNOON WITH AROUND 400-600 J/KG OF SBCAPE OVER THE CNTRL
AND SRN CWA. THIS SHOULD LEAD TO SCATTERED AFTERNOON SHOWERS AND
ISO THUNDERSTORMS ACROSS THE FA. SEVERE WEATHER GENERALLY SEEMS
UNLIKELY...BUT WITH THE STEEP MID LEVEL LAPSE RATES AND MODERATE
SHEAR SOME HAIL SEEMS POSSIBLE IF SUFFICIENT HEATING CAN TAKE
PLACE THROUGH THE MORNING. OTHERWISE THE SHOWERS AND ISO TSRA
SHOULD DIMINISH QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME
HEATING. THE SETUP FOR TUESDAY ISN`T AS FAVORABLE FOR AFTERNOON
TSRA AS THE LOW LEVEL RESIDUAL MOISTURE GETS DISPLACED TO THE EAST
AS CAA MOVES THROUGH THE FA BEHIND A SFC CDFNT ON MON NIGHT. THIS
WILL LEAD TO SEASONABLY COOL TEMPERATURES FOR TUE/WED. WE MAY SEE
AN ISO SHOWER IN THE NRN FA UNDER THE UPPER LEVEL LOW...BUT THESE
WILL BE PRETTY ISOLATED.
THE LOW FINALLY STARTS TO SHIFT EAST ON THU WITH DRY WEATHER
RETURNING...BUT THIS WILL ONLY BE FOR A SHORT TIME AS LONGER RANGE
MODELS ARE FAIRLY CONSISTENT IN BRINGING IN A TROUGH TO THE
WESTERN US WITH WAA TYPE PRECIP DEVELOPING STARTING ON FRI AND
INTO NEXT WEEKEND. WITH THE RETURN FLOW TEMPERATURES WILL ALSO BE
RETURNING TO NEAR NORMAL AS WELL.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
622 AM CDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT MON MAY 20 2013
TODAY AND TONIGHT...
THE BAND OF SHOWERS AND RAIN ACROSS THE SOUTHWESTERN AND NORTHEAST
PORTIONS OF THE FCST AREA SHOULD EXIT SOUTH AND EAST BY
DAYLIGHT...MID MORNING AT THE LATEST. THE RAP...HRRR AND NAM THEN
DROP A SECOND BATCH OF RAIN AND SHOWERS SOUTH OUT OF WRN SD THIS
MORNING AND THIS AFTN. THIS AREA OF RAIN SHOULD PRESUMABLY CONTINUE
MOVING SOUTH THIS EVENING WITH A WEAKENING TREND.
THUNDERSTORM CHANCES ARE VERY LOW IF THE RAP AND NAM ARE CORRECT.
NEITHER INDICATE ANY ELEVATED INSTABILITY FROM 750 MB ON UP AND THE
SFC BASED NAM THUNDERSTORM PROBABILITY CHART IS 10 PERCENT OR LESS.
WINDS INCREASE TO WIND ADVISORY CRITERIA TODAY ACROSS PARTS OF THE
WEST WITH H850 WINDS INCREASING TO 45 KT. THE MET AND MAV GUIDANCE
WERE THE BASIS FOR THE FORECAST WIND SPEEDS WHICH INCREASE TO AROUND
30 MPH. WINDS SHOULD SLACKEN THIS EVENING AS LOW PRESSURE ACROSS THE
NRN PLAINS BEGINS TO FILL.
TEMPERATURES ARE A BLEND OF NAM...GEMREG AND ECM PLUS BIAS
CORRECTION FOR HIGHS AND THE 50S AND 60S TODAY WITH LOWS IN THE 40S
AND 50S TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM CDT MON MAY 20 2013
ON TUESDAY...
THE UPPER LOW IS FORECAST TO MOVE FROM CENTRAL INTO FAR SOUTHEAST
SOUTH DAKOTA. A LOBE ON THE WESTERN PERIPHERY OF THE LOW WILL
ROTATE THROUGH WESTERN NEBRASKA WITH A CHANCE FOR SHOWERS MAINLY
ACROSS NORTH CENTRAL NEBRASKA. DESPITE A MOIST PROFILE...LIFT WILL
BE VERY WEAK...MAINLY IN THE H850-H7 LAYER. HAVE LOWERED POPS TO
NEAR 50 PERCENT FOR SHERIDAN AND WRN CHERRY AND FROM 30-40 PERCENT
ACROSS THE REMAINDER OF NCTRL WITH SLIGHT CHANCE POPS IN SWRN NEBR
IN THE MORNING. REGARDING WINDS...STRONGEST WINDS FORECAST FROM
THE EASTERN PANHANDLE INTO SOUTHWEST NEBR...WHERE SUSTAINED WIND
WILL REACH NEAR 25KT AND GUST NEAR 35KT THROUGH THE DAY. THIS IS
DUE TO DEEP MIX DOWN POTENTIAL WHERE UNIDIRECTIONAL NORTHWEST
WINDS EXTEND FROM THE SFC TO ABOVE 400 MB. THEREFORE A WIND
ADVISORY MAY BE NEEDED IF FORECAST WINDS CONTINUE TO LOOK SIMILAR.
HIGHS WILL BE AFFECTED MOST BY CLOUD COVER/SHOWERS FROM 55-60
NCTRL TO NEAR 70 FAR SW.
TUESDAY NIGHT AND WEDNESDAY...
AS UPPER LOW MOVES SLOWLY EAST ACROSS NRN IOWA...STILL SUPPORTIVE
OF A FEW SHOWERS TUES NIGHT NORTH CENTRAL AND NORTHEAST WEDNESDAY
AS WRAPAROUND MOISTURE STILL PRESENT. AN UPPER RIDGE WILL ALSO
BUILD INTO THE CNTRL ROCKIES WEDNESDAY IN RESPONSE TO A
SUBSTANTIAL CLOSED LOW DIGGING INTO THE PAC NW. CLEARING SKIES IN
THE WEST AND WEAK HIGH PRESSURE BUILDING IN TO BRING COOLER LOWS
FROM THE UPPER 30S TO LOWER 40S WEST TO NEAR 45 EAST. ONLY A MINOR
CHANGE TO HIGHS WEDNESDAY FROM 62-66 NCTRL TO 67-73 SOUTH.
THURSDAY THROUGH SUNDAY...
AN UNSETTLED WEATHER PATTERN WILL SET UP AS AN UPPER TROUGH
REMAINS ACROSS THE WESTERN U.S AND A RIDGE ACROSS THE CENTRAL
CONUS. ABUNDANT LOW LEVEL MOISTURE WILL INCREASE WITH H85
DEWPOINTS FROM 12-15C AT TIMES FRIDAY THROUGH SUNDAY. THE PRESENCE
OF A NOCTURNAL LOW LEVEL JET WILL ALSO ALLOW FOR THUNDERSTORMS TO
POSSIBLY DEVELOP INTO AN MCS ACROSS THE REGION EACH NIGHT. HIGHS
FROM THE UPPER 60S TO LOWER 70S THU-FRI WILL WARM TO THE UPPER 70S
TO LOWER 80S SAT-SUN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 616 AM CDT MON MAY 20 2013
MIXED VFR/MVFR FLIGHT CONDITIONS TODAY WITH MVFR IN SCATTERED
SHOWERS AND AREAS OF RAIN...MAINLY ACROSS NORTHWEST NEB. THE NAM
SUGGESTS THE RAIN WILL EXIT THE FORECAST AREA AROUND 03Z THIS
EVENING. THEREAFTER...MVFR CIGS MAY PERSIST ACROSS NRN NEB. BEST
APPROACH WOULD BE TO MONITOR CONDITIONS TO AS CONDITIONS ARE
MOSTLY VFR AND LOOK SIGNS OF DETERIORATION BEFORE ASSIGNING MVFR
TO THE KVTN TAF.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM MDT THIS EVENING
FOR NEZ004-022-023-035-056>058.
&&
$$
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT MON MAY 20 2013
TODAY AND TONIGHT...
THE BAND OF SHOWERS AND RAIN ACROSS THE SOUTHWESTERN AND NORTHEAST
PORTIONS OF THE FCST AREA SHOULD EXIT SOUTH AND EAST BY
DAYLIGHT...MID MORNING AT THE LATEST. THE RAP...HRRR AND NAM THEN
DROP A SECOND BATCH OF RAIN AND SHOWERS SOUTH OUT OF WRN SD THIS
MORNING AND THIS AFTN. THIS AREA OF RAIN SHOULD PRESUMABLY CONTINUE
MOVING SOUTH THIS EVENING WITH A WEAKENING TREND.
THUNDERSTORM CHANCES ARE VERY LOW IF THE RAP AND NAM ARE CORRECT.
NEITHER INDICATE ANY ELEVATED INSTABILITY FROM 750 MB ON UP AND THE
SFC BASED NAM THUNDERSTORM PROBABILITY CHART IS 10 PERCENT OR LESS.
WINDS INCREASE TO WIND ADVISORY CRITERIA TODAY ACROSS PARTS OF THE
WEST WITH H850 WINDS INCREASING TO 45 KT. THE MET AND MAV GUIDANCE
WERE THE BASIS FOR THE FORECAST WIND SPEEDS WHICH INCREASE TO AROUND
30 MPH. WINDS SHOULD SLACKEN THIS EVENING AS LOW PRESSURE ACROSS THE
NRN PLAINS BEGINS TO FILL.
TEMPERATURES ARE A BLEND OF NAM...GEMREG AND ECM PLUS BIAS
CORRECTION FOR HIGHS AND THE 50S AND 60S TODAY WITH LOWS IN THE 40S
AND 50S TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM CDT MON MAY 20 2013
ON TUESDAY...
THE UPPER LOW IS FORECAST TO MOVE FROM CENTRAL INTO FAR SOUTHEAST
SOUTH DAKOTA. A LOBE ON THE WESTERN PERIPHERY OF THE LOW WILL
ROTATE THROUGH WESTERN NEBRASKA WITH A CHANCE FOR SHOWERS MAINLY
ACROSS NORTH CENTRAL NEBRASKA. DESPITE A MOIST PROFILE...LIFT WILL
BE VERY WEAK...MAINLY IN THE H850-H7 LAYER. HAVE LOWERED POPS TO
NEAR 50 PERCENT FOR SHERIDAN AND WRN CHERRY AND FROM 30-40 PERCENT
ACROSS THE REMAINDER OF NCTRL WITH SLIGHT CHANCE POPS IN SWRN NEBR
IN THE MORNING. REGARDING WINDS...STRONGEST WINDS FORECAST FROM
THE EASTERN PANHANDLE INTO SOUTHWEST NEBR...WHERE SUSTAINED WIND
WILL REACH NEAR 25KT AND GUST NEAR 35KT THROUGH THE DAY. THIS IS
DUE TO DEEP MIX DOWN POTENTIAL WHERE UNIDIRECTIONAL NORTHWEST
WINDS EXTEND FROM THE SFC TO ABOVE 400 MB. THEREFORE A WIND
ADVISORY MAY BE NEEDED IF FORECAST WINDS CONTINUE TO LOOK SIMILAR.
HIGHS WILL BE AFFECTED MOST BY CLOUD COVER/SHOWERS FROM 55-60
NCTRL TO NEAR 70 FAR SW.
TUESDAY NIGHT AND WEDNESDAY...
AS UPPER LOW MOVES SLOWLY EAST ACROSS NRN IOWA...STILL SUPPORTIVE
OF A FEW SHOWERS TUES NIGHT NORTH CENTRAL AND NORTHEAST WEDNESDAY
AS WRAPAROUND MOISTURE STILL PRESENT. AN UPPER RIDGE WILL ALSO
BUILD INTO THE CNTRL ROCKIES WEDNESDAY IN RESPONSE TO A
SUBSTANTIAL CLOSED LOW DIGGING INTO THE PAC NW. CLEARING SKIES IN
THE WEST AND WEAK HIGH PRESSURE BUILDING IN TO BRING COOLER LOWS
FROM THE UPPER 30S TO LOWER 40S WEST TO NEAR 45 EAST. ONLY A MINOR
CHANGE TO HIGHS WEDNESDAY FROM 62-66 NCTRL TO 67-73 SOUTH.
THURSDAY THROUGH SUNDAY...
AN UNSETTLED WEATHER PATTERN WILL SET UP AS AN UPPER TROUGH
REMAINS ACROSS THE WESTERN U.S AND A RIDGE ACROSS THE CENTRAL
CONUS. ABUNDANT LOW LEVEL MOISTURE WILL INCREASE WITH H85
DEWPOINTS FROM 12-15C AT TIMES FRIDAY THROUGH SUNDAY. THE PRESENCE
OF A NOCTURNAL LOW LEVEL JET WILL ALSO ALLOW FOR THUNDERSTORMS TO
POSSIBLY DEVELOP INTO AN MCS ACROSS THE REGION EACH NIGHT. HIGHS
FROM THE UPPER 60S TO LOWER 70S THU-FRI WILL WARM TO THE UPPER 70S
TO LOWER 80S SAT-SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1222 AM CDT MON MAY 20 2013
A FRONT PUSHING THROUGH NEBRASKA TONIGHT WILL EVENTUALLY PUSH
SHOWERS AND THUNDERSTORMS OUT OF CENTRAL AND WESTERN NEBRASKA.
STORMS ARE EXPECTED TO CLEAR ONL-BBW-LBF BY 11Z.
AFTER 15Z...RAIN IS LIKELY TO DIP INTO NORTH CENTRAL NEBRASKA TO
NEAR MHN...TIF AND ONL AS A STORM SYSTEM MAKES ITS WAY ACROSS THE
NORTHERN PLAINS. ISOLATED THUNDERSTORMS COULD BE EMBEDDED IN THE
RAIN AREA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM MDT THIS EVENING
FOR NEZ004-022-023-035-056>058.
&&
$$
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
202 AM CDT MON MAY 20 2013
.SYNOPSIS...
ISSUED AT 335 PM CDT SUN MAY 19 2013
AT H5 CLOSED LOW OVER THE NORTHERN PLAINS WITH DEEP TROUGH OVER THE
WESTERN CONUS. H5 RIDGE INTO THE GREAT LAKES. H5 WAVE UNDERNEATH
RIDGE OVER THE SOUTHEAST WITH ASSOCIATED SHOWERS.
&&
.UPDATE...
ISSUED AT 154 AM CDT MON MAY 20 2013
A WIND ADVISORY IS IN PLACE ACROSS PARTS OF WESTERN NEBRASKA
TODAY. THE RAP AND OTHER MODELS SHOW H850 MB WINDS INCREASING TO
AROUND 45 KT AND THE MET AND MAV GUIDANCE HAVE BEEN FOLLOWED FOR
THIS ADVISORY. THIS IN LINE WITH KUDX VAD WIND PROFILER SHOWING 40
TO 50 KT AT 07Z. MERRIMAN PROFILER IS OUT OF SERVICE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 335 PM CDT SUN MAY 19 2013
LARGE UPPER LEVEL LOW WILL TRACK FROM NEBRASKA TONIGHT TO SOUTH
DAKOTA MONDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TONIGHT...WITH SHOWERY WEATHER TO CONTINUE ACROSS NORTHERN
NEBRASKA MONDAY. A SEVERE STORM OR TWO CANNOT BE RULED OUT ACROSS
CENTRAL INTO EASTERN PORTIONS OF NORTH CENTRAL NEBRASKA THIS
EVENING...WHERE STRONGER FLOW ALOFT RESIDES. H85 WIND SPEEDS
INCREASE CONSIDERABLE ON THE SOUTH SIDE OF THE UPPER LEVEL LOW
MONDAY...WITH SPEEDS AT THE SFC NEARING ADVISORY CRITERIA ACROSS FAR
WESTERN NEBRASKA AND THE PANHANDLE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 335 PM CDT SUN MAY 19 2013
MODELS IN GOOD AGREEMENT WITH SLOW EXIT OF UPPER LOW FROM THE
NORTHERN PLAINS. RAINSHOWERS WILL AFFECT NORTHERN PORTIONS OF
WESTERN NEBRASKA THROUGH WEDNESDAY. TEMPERATURES WILL BE SOME WHAT
COOLER WITH CLOUD COVER AND SCATTERED RAIN SHOWER. HYDROLOGY WILL
CONTINUE TO BE A CONCERN AND WILL HAVE TO WATCHED. LOWS IN THE 40S
AND HIGHS IN THE 60S NORTH TO LOW 70S SOUTHWEST. SHARP RIDGE
DEVELOPS OVER NORTHERN PLAINS WEDNESDAY THROUGH THURSDAY AS NEXT
SYSTEM DROPS SOUTHEAST OUT OF THE PACIFIC NORTHWEST. SOUTHWEST
FLOW AND DIVERGENCE ALOFT WITH GULF MOISTURE AVAILABLE EXPECT
THUNDERSTORM DEVELOPMENT THURSDAY NIGHT THROUGH SUNDAY MAINLY LATE
AFTERNOON AND EARLY EVENING. TEMPERATURES RISING INTO THE 70S AND
80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1222 AM CDT MON MAY 20 2013
A FRONT PUSHING THROUGH NEBRASKA TONIGHT WILL EVENTUALLY PUSH
SHOWERS AND THUNDERSTORMS OUT OF CENTRAL AND WESTERN NEBRASKA.
STORMS ARE EXPECTED TO CLEAR ONL-BBW-LBF BY 11Z.
AFTER 15Z...RAIN IS LIKELY TO DIP INTO NORTH CENTRAL NEBRASKA TO
NEAR MHN...TIF AND ONL AS A STORM SYSTEM MAKES ITS WAY ACROSS THE
NORTHERN PLAINS. ISOLATED THUNDERSTORMS COULD BE EMBEDDED IN THE
RAIN AREA.
&&
.HYDROLOGY...
ISSUED AT 335 PM CDT SUN MAY 19 2013
ISSUED SMALL STREAM FLOOD ADVISORY FOR KEITH AND SOUTHERN GARDEN
COUNTIES AS UPPER LOW KEEPS A NARROW BAND OF RAIN OVER THE
COUNTIES WITH ALREADY SATURATED GROUND FROM THUNDERSTORMS LAST
NIGHT. THE UPPER LOW IS PULLING SLOWLY EAST. SECONDARY ROADS ARE
MUDDY AND SOME HAVE WATER CROSSING THE ROAD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM MDT THIS EVENING
FOR NEZ004-022-023-035-056>058.
&&
$$
UPDATE...CDC
SYNOPSIS...POWER
SHORT TERM...TAYLOR
LONG TERM...POWER
AVIATION...CDC
HYDROLOGY...POWER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
232 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE TODAY AS A FRONTAL
BOUNDARY REMAINS NEAR OUR AREA. A BETTER THREAT FOR SHOWERS AND
THUNDERSTORMS WILL COME TUESDAY AND BEYOND AS A MORE SIGNIFICANT
FRONT AND LOW PRESSURE SYSTEM MOVE CLOSE TO OUR AREA. THE BIGGER
STORY WILL BE WARMER WEATHER WITH HIGH TEMPERATURES IN THE 70S TO
NEAR 80 THROUGH THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATED AT 1 PM... WEAK FRONTAL BOUNDARY IS CURRENTLY LOCATED
ACROSS FAR NORTHERN NEW YORK. SKIES HAVE BECOME PARTLY CLOUDY
SOUTH OF THE BOUNDARY ACROSS OUR AREA WITH SOME CONVECTIVE CLOUDS
DEVELOPING BUT NO INDICATIONS OF ANY DEEP CONVECTIVE DEVELOPMENT
THROUGH EARLY THIS AFTERNOON. LATEST RAP FORECASTS FOR THIS AFTERNOON
INDICATE INCREASING IN INSTABILITY WITH CAPE VALUES CLIMBING TO
800-1000 J/KG. HOWEVER SYNOPTIC-SCALE FORCING LOOKS WEAK WITH THE
FRONTAL BOUNDARY EXPECTED TO REMAIN TO THE NORTH. SOME HIGH
RESOLUTION MODELS SHOWING ISOLATED CONVECTIVE SHOWERS DEVELOPING
OVER CENTRAL NY LATER THIS AFTERNOON WITH COVERAGE LESS THAN 30
PERCENT. WEAK WIND FIELDS WOULD MEAN THAT ANY STORMS THAT DEVELOP
WILL BE OF THE PULSE VARIETY WITH ANY SEVERE THREAT LOW. WITH
CLEARING TEMPERATURES HAVE CLIMBED INTO THE 70S AND MANY PLACES
WILL REACH NEAR 80 THIS AFTERNOON.
1000 AM UPDATE...MADE MINOR CHANGES TO SHOW MORE OF A DRY FORECAST
ACROSS OUR AREA NOW AND FOR THE NEXT FEW HOURS AS THE CLOSEST AREA
OF SHOWERS OVER NNY WILL SAFELY PASS TO OUR NORTHEAST. STILL NOT
SEEING ANY BIG TRIGGERS FOR SHOWERS OR CONVECTION THIS AFTERNOON
SO SLIGHT CHANCE POPS SEEMS GREAT. THE HRRR DOES SHOW SOMETHING
CROSSING LAKE ERIE LATE IN THE DAY AND IT DOES MATCH UP NOW WITH A
DEVELOPING LINE OF CONVECTION OVER LOWER MICHIGAN SO WE WILL WATCH
THIS CLOSELY. IN ADDITION WHILE DRY NOW...VIS SATELLITE DOES SHOW
SOME MORE LUMPY OR CONVECTIVE LOOKING CUMULUS OVER THE FAR
NORTHEAST END OF LAKE ONTARIO SO THIS MAY TURN INTO SOMETHING IN
THE NEXT FEW HOURS. AGAIN NOT MUCH EXPECTED BUT ENOUGH AROUND TO
WARRANT AT LEAST A MENTION THIS PM. UNLIKE YESTERDAY SUNSHINE OVER
IS ALREADY OVER THE NORTHERN PART OF THE CWA AND WILL CONTINUE TO
PUSH SOUTH THROUGH MIDDAY. TEMPS LOOK ON TRACK TO REACH THE 70S.
THE PREVIOUS AFD IS BELOW...
4 AM UPDATE...
WK SFC LOW LOCATED ACRS SRN QUEBEC WL SLIDE OFF TO THE EAST TDA AS
UL WV PULLS EAST. AS IT DOES SO A WK SFC TROF WL APPCH NRN ZONES
THIS AFTN BFR IT WASHES OUT. AT THE SAME TIME A STRONG CLOSED LOW
ALOFT WL PINWHEEL ACRS THE NRN PLAINS FOR THE NEXT DAY OR TWO. THIS
LOW WHICH WAS RESPONSIBLE FOR YDA`S TORNADO OUTBREAK ACRS THE SRN
PLAINS IS ESSENTIALLY BLOCKED IN PLACE BY RIDGING TO THE EAST AND
WEST. LOW PROGGED TO BE STACKED THRU TUESDAY SWINGING A WMFNT THRU
THE AREA ON MON NGT.
FOR TDA, PATCHY FOG AND DRIZZLE CAN BE EXPECTED ACRS SRN ZONES AS
MARINE LYR RMNS THRU AT LEAST 12Z. AFT THIS TIME, WINDS BCM MORE
SWRLY LEADING TO SOME IMPROVEMENT IN LOW CLDS. WHILE LOW-LVL
MOISTURE WL RMN IN PLACE THIS AFTN, VRY LITTLE FRCG WL BE AVAILABLE
FOR ANY NOTICEABLE PCPN TDA AND WITH MODELS CONTG TO INDICATE
WIDESPREAD QPF ACRS THE AREA AND GIVEN THEIR PERFORMANCES THE LAST 2
DAYS, HV LWRD POPS OVR ENTIRE CWA TO ISOLD AT BEST. IS THE POTENTIAL
FOR AN ISOLD RUMBLE OR TWO OF THUNDER AND HV INCLUDED MENTION TWD
NOON UP NR BNDRY SLIPPING THRU AND OVRSPRDNG ENTIRE AREA THRU ABOUT
21Z. OF COURSE, LIMITATIONS EXIST STRICTLY FM EXTENSIVE CLD CVR
ALONG WITH WK FRCG BUT FEEL CHCS ARE NOT COMPLETELY NIL SO HV CONTD
ISOLD SHRA/TSRA CHC FOR THE AFTN.
FOR TONIGHT, WMFNT LIFTS THRU WITH OVRNGT LOWS EXPECTED TO RMN ARND
60F. DWPTS WL ONLY DROP INTO THE U50S. SKIES WL RANGE FM
PRTLY-MOCLDY DRG THE NIGHTTIME HRS WITH BNDRY IN VICINITY. SLGT CHC
POPS THRU MOST OF THE OVRNGT HRS THEN SLOWLY INCRSNG TWD DAWN FM THE
WEST AS ISENTROPIC LIFT INCREASES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
4 AM UPDATE...
SW FLOW CONTS ON TUESDAY PER 00Z NAM AND ECMWF. MODELS PLACE CWA
SQUARELY IN THE WARM SECTOR DRG THE DAY. H5 RIDGE BEGINS TO WEAKEN
DRG THE AFTN AS PLAINS LOW BEGINS TO EJECT TO THE EAST. THIS WL
ALLOW WK S/WV TO IMPACT AREA DRG THE DAY, LEADING TO LKLY POPS AFT
18Z. AIRMASS WL LKLY DESTABILIZE IN WM SECTOR LEADING TO CAPES ARND
1000 J/KG BASED ON TEMPS IN THE LWR 80S AND DWPTS RISING INTO THE
MID-60S.
CHC FOR SHOWERS AND TSTMS CONTINUES THRU THE DAY ON WED AS WMFNT
RMNS TO OUR NORTH AND INSTABILITY GRADUALLY INCREASES. DUE TO
PROXIMITY OF BNDRY, SHOWERS APPEAR TO BE LKLY AT TIMES DRG THE DAY
ACRS CNTRL NY CNTYS WHILE ONLY SCTD THUNDER CAN BE EXPECTED, THUS HV
WORDED GRIDS AS LKLY SHOWERS AND CHANCE THUNDER.
MAV NUMBERS LOOK WAY TOO WARM FOR HIGHS ON WEDNESDAY DUE TO THE
GFS/S LACK OF CLD CVR. THINKING IS THAT MET NUMBERS WILL BE CLOSER
TO REALITY AND VLY LOCALES MAY HIT 80F BUT HILLTOPS WL RMN IN THE
U70S.
HV CONTD LKLY POPS WED NGT AS CD FNT APPCHS WRN NY AND H5 LOW EJECTS
INTO GREAT LKS, FLINGING WVS AT TIMES THRU THE PD. HV MADE VRY FEW
CHGS TO PRVS GRIDS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS CONTINUE TO SHOW A DEEP UPPER LEVEL TROF OVER
THE NORTHEAST THROUGH MOST OF THE PERIOD WITH HEIGHTS GRADUALLY
BUILDING LATE AS THIS TROF LIFTS EAST. THIS WILL KEEP TEMPERATURES
5-10 DEGREES BELOW NORMAL WITH MIN TEMPS COLD ENOUGH FOR POSSIBLE
FROST BOTH FRIDAY/SATURDAY NIGHTS AND MAYBE EVEN SUNDAY NIGHT.
AT THE SFC, POST COLD FRONT SHOWERS/THUNDERSTORMS WILL LINGER
THROUGH THE OVERNIGHT PERIOD WITH BEST CHC FOR THUNDER DURING THE
EARLY EVENING. AS THE UPPER LEVEL TROF BUILDS IN ON FRIDAY THE CHC
FOR SHOWERS WILL CONTINUE WITH THE HIGHEST POPS IN THE SOUTHERN
CATSKILLS AND NE PA. REMAINDER OF PERIOD WILL BE DRY WITH PARTLY
TO MAINLY CLEAR CONDITIONS AS SFC HIGH PRES FROM CENTRAL CANADA
DROPS SOUTH ACROSS THE GREAT LAKES REGION TO OUR VCNTY BY MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
CONDITIONS ARE VFR ACROSS THE TERMINALS THIS AFTERNOON AND IN
GENERAL WILL REMAIN VFR THROUGH THIS TAF PERIOD. LATE TONIGHT, MVFR
CONDITIONS ARE POSSIBLE AT KELM DUE TO VALLEY FOG AND KAVP WITH
POSSIBLE MARINE LAYER.
THERE IS THE POTENTIAL FOR CONVECTION PRIMARILY TUESDAY AFTERNOON AS
WEAK BOUNDARY OVER NORTHERN NY MAY BECOME ACTIVE WITH DIURNAL
INSTABILITY. SHOWERS/THUNDERSTORMS ARE NOT INCLUDED IN THE TAFS
ATTM AS THE BEST CHANCE LOOKS AFTER 18Z BUT OVERALL A LOW
CONFIDENCE CONVECTIVE EVENT UNFOLDING TOMORROW AFTERNOON.
LIGHT AND VARIABLE WITH THROUGH TONIGHT BECOMING SOUTHWEST AT
5-10 KNOTS TUESDAY MORNING.
OUTLOOK...
WEDNESDAY/THURSDAY...MVFR POSSIBLE IN SHOWERS/THUNDERSTORMS.
FRIDAY/SATURDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...MSE/PVN
SHORT TERM...HEDEN/PVN
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
125 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE TODAY AS A FRONTAL
BOUNDARY REMAINS NEAR OUR AREA. A BETTER THREAT FOR SHOWERS AND
THUNDERSTORMS WILL COME TUESDAY AND BEYOND AS A MORE SIGNIFICANT
FRONT AND LOW PRESSURE SYSTEM MOVE CLOSE TO OUR AREA. THE BIGGER
STORY WILL BE WARMER WEATHER WITH HIGH TEMPERATURES IN THE 70S TO
NEAR 80 THROUGH THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATED AT 1 PM... WEAK FRONTAL BOUNDARY IS CURRENTLY LOCATED
ACROSS FAR NORTHERN NEW YORK. SKIES HAVE BECOME PARTLY CLOUDY
SOUTH OF THE BOUNDARY ACROSS OUR AREA WITH SOME CONVECTIVE CLOUDS
DEVELOPING BUT NO INDICATIONS OF ANY DEEP CONVECTIVE DEVELOPMENT
THROUGH EARLY THIS AFTERNOON. LATEST RAP FORECASTS FOR THIS AFTERNOON
INDICATE INCREASING IN INSTABILITY WITH CAPE VALUES CLIMBING TO
800-1000 J/KG. HOWEVER SYNOPTIC-SCALE FORCING LOOKS WEAK WITH THE
FRONTAL BOUNDARY EXPECTED TO REMAIN TO THE NORTH. SOME HIGH
RESOLUTION MODELS SHOWING ISOLATED CONVECTIVE SHOWERS DEVELOPING
OVER CENTRAL NY LATER THIS AFTERNOON WITH COVERAGE LESS THAN 30
PERCENT. WEAK WIND FIELDS WOULD MEAN THAT ANY STORMS THAT DEVELOP
WILL BE OF THE PULSE VARIETY WITH ANY SEVERE THREAT LOW. WITH
CLEARING TEMPERATURES HAVE CLIMBED INTO THE 70S AND MANY PLACES
WILL REACH NEAR 80 THIS AFTERNOON.
1000 AM UPDATE...MADE MINOR CHANGES TO SHOW MORE OF A DRY FORECAST
ACROSS OUR AREA NOW AND FOR THE NEXT FEW HOURS AS THE CLOSEST AREA
OF SHOWERS OVER NNY WILL SAFELY PASS TO OUR NORTHEAST. STILL NOT
SEEING ANY BIG TRIGGERS FOR SHOWERS OR CONVECTION THIS AFTERNOON
SO SLIGHT CHANCE POPS SEEMS GREAT. THE HRRR DOES SHOW SOMETHING
CROSSING LAKE ERIE LATE IN THE DAY AND IT DOES MATCH UP NOW WITH A
DEVELOPING LINE OF CONVECTION OVER LOWER MICHIGAN SO WE WILL WATCH
THIS CLOSELY. IN ADDITION WHILE DRY NOW...VIS SATELLITE DOES SHOW
SOME MORE LUMPY OR CONVECTIVE LOOKING CUMULUS OVER THE FAR
NORTHEAST END OF LAKE ONTARIO SO THIS MAY TURN INTO SOMETHING IN
THE NEXT FEW HOURS. AGAIN NOT MUCH EXPECTED BUT ENOUGH AROUND TO
WARRANT AT LEAST A MENTION THIS PM. UNLIKE YESTERDAY SUNSHINE OVER
IS ALREADY OVER THE NORTHERN PART OF THE CWA AND WILL CONTINUE TO
PUSH SOUTH THROUGH MIDDAY. TEMPS LOOK ON TRACK TO REACH THE 70S.
THE PREVIOUS AFD IS BELOW...
4 AM UPDATE...
WK SFC LOW LOCATED ACRS SRN QUEBEC WL SLIDE OFF TO THE EAST TDA AS
UL WV PULLS EAST. AS IT DOES SO A WK SFC TROF WL APPCH NRN ZONES
THIS AFTN BFR IT WASHES OUT. AT THE SAME TIME A STRONG CLOSED LOW
ALOFT WL PINWHEEL ACRS THE NRN PLAINS FOR THE NEXT DAY OR TWO. THIS
LOW WHICH WAS RESPONSIBLE FOR YDA`S TORNADO OUTBREAK ACRS THE SRN
PLAINS IS ESSENTIALLY BLOCKED IN PLACE BY RIDGING TO THE EAST AND
WEST. LOW PROGGED TO BE STACKED THRU TUESDAY SWINGING A WMFNT THRU
THE AREA ON MON NGT.
FOR TDA, PATCHY FOG AND DRIZZLE CAN BE EXPECTED ACRS SRN ZONES AS
MARINE LYR RMNS THRU AT LEAST 12Z. AFT THIS TIME, WINDS BCM MORE
SWRLY LEADING TO SOME IMPROVEMENT IN LOW CLDS. WHILE LOW-LVL
MOISTURE WL RMN IN PLACE THIS AFTN, VRY LITTLE FRCG WL BE AVAILABLE
FOR ANY NOTICEABLE PCPN TDA AND WITH MODELS CONTG TO INDICATE
WIDESPREAD QPF ACRS THE AREA AND GIVEN THEIR PERFORMANCES THE LAST 2
DAYS, HV LWRD POPS OVR ENTIRE CWA TO ISOLD AT BEST. IS THE POTENTIAL
FOR AN ISOLD RUMBLE OR TWO OF THUNDER AND HV INCLUDED MENTION TWD
NOON UP NR BNDRY SLIPPING THRU AND OVRSPRDNG ENTIRE AREA THRU ABOUT
21Z. OF COURSE, LIMITATIONS EXIST STRICTLY FM EXTENSIVE CLD CVR
ALONG WITH WK FRCG BUT FEEL CHCS ARE NOT COMPLETELY NIL SO HV CONTD
ISOLD SHRA/TSRA CHC FOR THE AFTN.
FOR TONIGHT, WMFNT LIFTS THRU WITH OVRNGT LOWS EXPECTED TO RMN ARND
60F. DWPTS WL ONLY DROP INTO THE U50S. SKIES WL RANGE FM
PRTLY-MOCLDY DRG THE NIGHTTIME HRS WITH BNDRY IN VICINITY. SLGT CHC
POPS THRU MOST OF THE OVRNGT HRS THEN SLOWLY INCRSNG TWD DAWN FM THE
WEST AS ISENTROPIC LIFT INCREASES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
4 AM UPDATE...
SW FLOW CONTS ON TUESDAY PER 00Z NAM AND ECMWF. MODELS PLACE CWA
SQUARELY IN THE WARM SECTOR DRG THE DAY. H5 RIDGE BEGINS TO WEAKEN
DRG THE AFTN AS PLAINS LOW BEGINS TO EJECT TO THE EAST. THIS WL
ALLOW WK S/WV TO IMPACT AREA DRG THE DAY, LEADING TO LKLY POPS AFT
18Z. AIRMASS WL LKLY DESTABILIZE IN WM SECTOR LEADING TO CAPES ARND
1000 J/KG BASED ON TEMPS IN THE LWR 80S AND DWPTS RISING INTO THE
MID-60S.
CHC FOR SHOWERS AND TSTMS CONTINUES THRU THE DAY ON WED AS WMFNT
RMNS TO OUR NORTH AND INSTABILITY GRADUALLY INCREASES. DUE TO
PROXIMITY OF BNDRY, SHOWERS APPEAR TO BE LKLY AT TIMES DRG THE DAY
ACRS CNTRL NY CNTYS WHILE ONLY SCTD THUNDER CAN BE EXPECTED, THUS HV
WORDED GRIDS AS LKLY SHOWERS AND CHANCE THUNDER.
MAV NUMBERS LOOK WAY TOO WARM FOR HIGHS ON WEDNESDAY DUE TO THE
GFS/S LACK OF CLD CVR. THINKING IS THAT MET NUMBERS WILL BE CLOSER
TO REALITY AND VLY LOCALES MAY HIT 80F BUT HILLTOPS WL RMN IN THE
U70S.
HV CONTD LKLY POPS WED NGT AS CD FNT APPCHS WRN NY AND H5 LOW EJECTS
INTO GREAT LKS, FLINGING WVS AT TIMES THRU THE PD. HV MADE VRY FEW
CHGS TO PRVS GRIDS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
445 AM UPDATE...
VERY LITTLE CHANGE FROM INHERITED FCST WITH STRONG COLD FRONT
STILL EXPECTED TO PASS THROUGH THE REGION ON THURSDAY. MODELS
CONTINUE TO ADVERTISE A FAIRLY DECENT COOL DOWN FOR THE UPCOMING
WEEKEND WITH THE LATEST ARRIVING 00Z ECMWF NOT AS COOL AS PREVIOUS
RUNS...WHICH IS NOW MORE IN LINE WITH THE GFS AND CANADIAN-CMC.
THAT SAID...STILL LOOKING FOR OVERNIGHT LOWS TO DIP DOWN INTO THE
MIDDLE TO UPPER 30S ACROSS FAVORED VALLEY LOCATIONS NEXT WEEKEND
WHICH WILL LIKELY LEAD TO FROST CONCERNS. UPCOMING WEEKEND STILL
LOOKING DRY AS STRONG HIGH PRESSURE NOSES SOUTH FROM SOUTHERN
CANADA.
PREVIOUS LONG TERM DISCUSSION... THE EXTENDED FORECAST WILL
FEATURE A DEEP UPPER LEVEL TROF OVER THE NORTHEAST KEEPING TEMPS
WELL BELOW NORMAL THROUGH THE PERIOD AFTER A COLD FRONTAL PASSAGE
ON THURSDAY.
AT THE SFC, A COLD FRONT WILL APPROACH THE REGION WEDNESDAY NIGHT
WITH FROPA ON THURSDAY. WILL CONTINUE WITH HIGH CHC/LIKELY POPS
THROUGH THIS PERIOD ALONG WITH THE CHC FOR THUNDERSTORMS. BUILDING
UPPER LEVEL TROF AND LINGERING POST FRONTAL MOISTURE WILL KEEP THE
THREAT FOR SHOWERS INTO FRIDAY. THE REMAINDER OF THE PERIOD WILL
BE DRY WITH PARTLY TO MAINLY CLEAR SKIES AS SFC HIGH PRES DROPS
SOUTH OVER THE AREA FROM CENTRAL CANADA. LOWS BOTH FRIDAY AND
SATURDAY NIGHT MAY BE COLD ENOUGH FOR FROST.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
FAINT HINTS THROUGH OVERLYING CIRRUS THAT LINGERING MARINE LAYER
IS BEGINNING TO RETREAT AS WINDS BECOME MORE SOUTHERLY WITH TIME
THIS MORNING. IN FACT...SYR HAS ACTUALLY CLEARED OUT AND IS NOW
REPORTING VFR CONDITIONS. IN ANY EVENT...EXPECT THIS TREND TO
CONTINUE THIS MORNING AS WINDS CONTINUE TO VEER AND DAYTIME
HEATING COMMENCES. FOR NOW WE EXPECT IFR CONDITIONS TO LINGER AT
BGM FOR A FEW MORE HRS THROUGH ROUGHLY 14Z WITH IMPROVEMENTS
ANTICIPATED SHORTLY THEREAFTER. AT ELM AND ITH...IF IFR WERE TO
OCCUR THIS MORNING...IT WILL LIKELY ONLY BE BRIEF BEFORE THINGS
IMPROVE. BY LATE MORNING...ALL SITES SHOULD BE VFR WITH WEAK
SOUTHERLY WINDS OF 4-8 KTS PREVAILING REGION WIDE.
AS FOR SHWRS/STORMS...WEAK FRONTAL BOUNDARY NORTH OF THE FCST AREA
MAY SERVE AS A TRIGGER FOR DEVELOPING ACTIVITY. FOR NOW...BEST
POTENTIAL WILL BE FOR SYR AND RME HOWEVER WEAK WIND FIELD ALOFT
AND NO HINT OF ANY APPROACHING UPPER SUPPORT LEADS TO A FAIR AMOUNT
OF UNCERTAINTY AND THUS NO MENTION IN THE FCST AS OF NOW.
FOR TONIGHT...EXPECT POSSIBLE IFR CONDITIONS AFTER 06Z AT AVP IN
MOIST SOUTHWEST FLOW. FOR NOW...OVERALL CONFIDENCE OF RESTRICTIONS
AT REMAINING SITES REMAINS TOO LOW TO INCLUDE IN THE FCST DUE TO
MODEL/S SUGGESTION OF DRIER AIR OVER CENTRAL NY.
OUTLOOK...
TUESDAY/WEDNESDAY/THURSDAY...MVFR POSSIBLE IN SHOWERS/THUNDERSTORMS.
FRIDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...MSE/PVN
SHORT TERM...HEDEN/PVN
LONG TERM...CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1015 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE TODAY AS A FRONTAL
BOUNDARY REMAINS NEAR OUR AREA. A BETTER THREAT FOR SHOWERS AND
THUNDERSTORMS WILL COME TUESDAY AND BEYOND AS A MORE SIGNIFICANT
FRONT AND LOW PRESSURE SYSTEM MOVE CLOSE TO OUR AREA. THE BIGGER
STORY WILL BE WARMER WEATHER WITH HIGH TEMPERATURES IN THE 70S TO
NEAR 80 THROUGH THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
1000 AM UPDATE...MADE MINOR CHANGES TO SHOW MORE OF A DRY FORECAST
ACROSS OUR AREA NOW AND FOR THE NEXT FEW HOURS AS THE CLOSEST AREA
OF SHOWERS OVER NNY WILL SAFELY PASS TO OUR NORTHEAST. STILL NOT
SEEING ANY BIG TRIGGERS FOR SHOWERS OR CONVECTION THIS AFTERNOON
SO SLIGHT CHANCE POPS SEEMS GREAT. THE HRRR DOES SHOW SOMETHING
CROSSING LAKE ERIE LATE IN THE DAY AND IT DOES MATCH UP NOW WITH A
DEVELOPING LINE OF CONVECTION OVER LOWER MICHIGAN SO WE WILL WATCH
THIS CLOSELY. IN ADDITION WHILE DRY NOW...VIS SATELLITE DOES SHOW
SOME MORE LUMPY OR CONVECTIVE LOOKING CUMULUS OVER THE FAR
NORTHEAST END OF LAKE ONTARIO SO THIS MAY TURN INTO SOMETHING IN
THE NEXT FEW HOURS. AGAIN NOT MUCH EXPECTED BUT ENOUGH AROUND TO
WARRANT AT LEAST A MENTION THIS PM. UNLIKE YESTERDAY SUNSHINE OVER
IS ALREADY OVER THE NORTHERN PART OF THE CWA AND WILL CONTINUE TO
PUSH SOUTH THROUGH MIDDAY. TEMPS LOOK ON TRACK TO REACH THE 70S.
THE PREVIOUS AFD IS BELOW...
4 AM UPDATE...
WK SFC LOW LOCATED ACRS SRN QUEBEC WL SLIDE OFF TO THE EAST TDA AS
UL WV PULLS EAST. AS IT DOES SO A WK SFC TROF WL APPCH NRN ZONES
THIS AFTN BFR IT WASHES OUT. AT THE SAME TIME A STRONG CLOSED LOW
ALOFT WL PINWHEEL ACRS THE NRN PLAINS FOR THE NEXT DAY OR TWO. THIS
LOW WHICH WAS RESPONSIBLE FOR YDA`S TORNADO OUTBREAK ACRS THE SRN
PLAINS IS ESSENTIALLY BLOCKED IN PLACE BY RIDGING TO THE EAST AND
WEST. LOW PROGGED TO BE STACKED THRU TUESDAY SWINGING A WMFNT THRU
THE AREA ON MON NGT.
FOR TDA, PATCHY FOG AND DRIZZLE CAN BE EXPECTED ACRS SRN ZONES AS
MARINE LYR RMNS THRU AT LEAST 12Z. AFT THIS TIME, WINDS BCM MORE
SWRLY LEADING TO SOME IMPROVEMENT IN LOW CLDS. WHILE LOW-LVL
MOISTURE WL RMN IN PLACE THIS AFTN, VRY LITTLE FRCG WL BE AVAILABLE
FOR ANY NOTICEABLE PCPN TDA AND WITH MODELS CONTG TO INDICATE
WIDESPREAD QPF ACRS THE AREA AND GIVEN THEIR PERFORMANCES THE LAST 2
DAYS, HV LWRD POPS OVR ENTIRE CWA TO ISOLD AT BEST. IS THE POTENTIAL
FOR AN ISOLD RUMBLE OR TWO OF THUNDER AND HV INCLUDED MENTION TWD
NOON UP NR BNDRY SLIPPING THRU AND OVRSPRDNG ENTIRE AREA THRU ABOUT
21Z. OF COURSE, LIMITATIONS EXIST STRICTLY FM EXTENSIVE CLD CVR
ALONG WITH WK FRCG BUT FEEL CHCS ARE NOT COMPLETELY NIL SO HV CONTD
ISOLD SHRA/TSRA CHC FOR THE AFTN.
FOR TONIGHT, WMFNT LIFTS THRU WITH OVRNGT LOWS EXPECTED TO RMN ARND
60F. DWPTS WL ONLY DROP INTO THE U50S. SKIES WL RANGE FM
PRTLY-MOCLDY DRG THE NIGHTTIME HRS WITH BNDRY IN VICINITY. SLGT CHC
POPS THRU MOST OF THE OVRNGT HRS THEN SLOWLY INCRSNG TWD DAWN FM THE
WEST AS ISENTROPIC LIFT INCREASES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
4 AM UPDATE...
SW FLOW CONTS ON TUESDAY PER 00Z NAM AND ECMWF. MODELS PLACE CWA
SQUARELY IN THE WARM SECTOR DRG THE DAY. H5 RIDGE BEGINS TO WEAKEN
DRG THE AFTN AS PLAINS LOW BEGINS TO EJECT TO THE EAST. THIS WL
ALLOW WK S/WV TO IMPACT AREA DRG THE DAY, LEADING TO LKLY POPS AFT
18Z. AIRMASS WL LKLY DESTABILIZE IN WM SECTOR LEADING TO CAPES ARND
1000 J/KG BASED ON TEMPS IN THE LWR 80S AND DWPTS RISING INTO THE
MID-60S.
CHC FOR SHOWERS AND TSTMS CONTINUES THRU THE DAY ON WED AS WMFNT
RMNS TO OUR NORTH AND INSTABILITY GRADUALLY INCREASES. DUE TO
PROXIMITY OF BNDRY, SHOWERS APPEAR TO BE LKLY AT TIMES DRG THE DAY
ACRS CNTRL NY CNTYS WHILE ONLY SCTD THUNDER CAN BE EXPECTED, THUS HV
WORDED GRIDS AS LKLY SHOWERS AND CHANCE THUNDER.
MAV NUMBERS LOOK WAY TOO WARM FOR HIGHS ON WEDNESDAY DUE TO THE
GFS/S LACK OF CLD CVR. THINKING IS THAT MET NUMBERS WILL BE CLOSER
TO REALITY AND VLY LOCALES MAY HIT 80F BUT HILLTOPS WL RMN IN THE
U70S.
HV CONTD LKLY POPS WED NGT AS CD FNT APPCHS WRN NY AND H5 LOW EJECTS
INTO GREAT LKS, FLINGING WVS AT TIMES THRU THE PD. HV MADE VRY FEW
CHGS TO PRVS GRIDS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
445 AM UPDATE...
VERY LITTLE CHANGE FROM INHERITED FCST WITH STRONG COLD FRONT
STILL EXPECTED TO PASS THROUGH THE REGION ON THURSDAY. MODELS
CONTINUE TO ADVERTISE A FAIRLY DECENT COOL DOWN FOR THE UPCOMING
WEEKEND WITH THE LATEST ARRIVING 00Z ECMWF NOT AS COOL AS PREVIOUS
RUNS...WHICH IS NOW MORE IN LINE WITH THE GFS AND CANADIAN-CMC.
THAT SAID...STILL LOOKING FOR OVERNIGHT LOWS TO DIP DOWN INTO THE
MIDDLE TO UPPER 30S ACROSS FAVORED VALLEY LOCATIONS NEXT WEEKEND
WHICH WILL LIKELY LEAD TO FROST CONCERNS. UPCOMING WEEKEND STILL
LOOKING DRY AS STRONG HIGH PRESSURE NOSES SOUTH FROM SOUTHERN
CANADA.
PREVIOUS LONG TERM DISCUSSION... THE EXTENDED FORECAST WILL
FEATURE A DEEP UPPER LEVEL TROF OVER THE NORTHEAST KEEPING TEMPS
WELL BELOW NORMAL THROUGH THE PERIOD AFTER A COLD FRONTAL PASSAGE
ON THURSDAY.
AT THE SFC, A COLD FRONT WILL APPROACH THE REGION WEDNESDAY NIGHT
WITH FROPA ON THURSDAY. WILL CONTINUE WITH HIGH CHC/LIKELY POPS
THROUGH THIS PERIOD ALONG WITH THE CHC FOR THUNDERSTORMS. BUILDING
UPPER LEVEL TROF AND LINGERING POST FRONTAL MOISTURE WILL KEEP THE
THREAT FOR SHOWERS INTO FRIDAY. THE REMAINDER OF THE PERIOD WILL
BE DRY WITH PARTLY TO MAINLY CLEAR SKIES AS SFC HIGH PRES DROPS
SOUTH OVER THE AREA FROM CENTRAL CANADA. LOWS BOTH FRIDAY AND
SATURDAY NIGHT MAY BE COLD ENOUGH FOR FROST.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
FAINT HINTS THROUGH OVERLYING CIRRUS THAT LINGERING MARINE LAYER
IS BEGINNING TO RETREAT AS WINDS BECOME MORE SOUTHERLY WITH TIME
THIS MORNING. IN FACT...SYR HAS ACTUALLY CLEARED OUT AND IS NOW
REPORTING VFR CONDITIONS. IN ANY EVENT...EXPECT THIS TREND TO
CONTINUE THIS MORNING AS WINDS CONTINUE TO VEER AND DAYTIME
HEATING COMMENCES. FOR NOW WE EXPECT IFR CONDITIONS TO LINGER AT
BGM FOR A FEW MORE HRS THROUGH ROUGHLY 14Z WITH IMPROVEMENTS
ANTICIPATED SHORTLY THEREAFTER. AT ELM AND ITH...IF IFR WERE TO
OCCUR THIS MORNING...IT WILL LIKELY ONLY BE BRIEF BEFORE THINGS
IMPROVE. BY LATE MORNING...ALL SITES SHOULD BE VFR WITH WEAK
SOUTHERLY WINDS OF 4-8 KTS PREVAILING REGION WIDE.
AS FOR SHWRS/STORMS...WEAK FRONTAL BOUNDARY NORTH OF THE FCST AREA
MAY SERVE AS A TRIGGER FOR DEVELOPING ACTIVITY. FOR NOW...BEST
POTENTIAL WILL BE FOR SYR AND RME HOWEVER WEAK WIND FIELD ALOFT
AND NO HINT OF ANY APPROACHING UPPER SUPPORT LEADS TO A FAIR AMOUNT
OF UNCERTAINTY AND THUS NO MENTION IN THE FCST AS OF NOW.
FOR TONIGHT...EXPECT POSSIBLE IFR CONDITIONS AFTER 06Z AT AVP IN
MOIST SOUTHWEST FLOW. FOR NOW...OVERALL CONFIDENCE OF RESTRICTIONS
AT REMAINING SITES REMAINS TOO LOW TO INCLUDE IN THE FCST DUE TO
MODEL/S SUGGESTION OF DRIER AIR OVER CENTRAL NY.
OUTLOOK...
TUESDAY/WEDNESDAY/THURSDAY...MVFR POSSIBLE IN SHOWERS/THUNDERSTORMS.
FRIDAY...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...HEDEN/PVN
LONG TERM...CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
331 PM EDT MON MAY 20 2013
.SYNOPSIS...
A DISTURBANCE ALOFT MOVING ACROSS THE AREA WILL MAINTAIN SHOWERS AND
THUNDERSTORMS THROUGH TUESDAY. DRIER AND WARMER WEATHER IS EXPECTED
MID WEEK. A COLD FRONT IS EXPECTED TO APPROACH AND CROSS THE REGION
ON FRIDAY...BRINGING DRIER AND SLIGHTLY COOLER WEATHER INTO THE NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 300 PM MONDAY...SPC MESOANALYSIS PAGE SHOWS THE HEAVIEST
CONVECTIVE RAINFALL IN ENCOMPASSED WITHIN A DEEP POCKET OF MOISTURE
STREWN ACROSS THE CENTRAL AND EASTERN CAROLINAS...WHERE PRECIPITABLE
WATERS WERE ESTIMATED AROUND 1.8 INCHES THIS AFTERNOON. WATER VAPOR
ANIMATIONS DEPICT A COMPLEX SET OF SWIRLS EMBEDDED WITHIN A WEAK
UPPER TROUGH FROM VIRGINIA TO NORTHERN FLORIDA. DIURNAL COOLING
INTO EVENING SHOULD REMOVE SOME INTENSITY OF CONVECTION...BUT GOOD
UPPER SUPPORT AND A MOISTURE RICH ENVIRONMENT SHOULD ALLOW FOR A
FEW BIG RAIN-MAKERS TO PERSIST THROUGH EVENING. THE OVERNIGHT
PERIOD WILL LIKELY SEE RE-DEVELOPMENT OVER THE WATERS AS LOW-LEVEL
BUOYANCY INCREASES. CIRCULATION AROUND BERMUDA HIGH PRESSURE WILL
HELP GUIDE OCEAN ACTIVITY ONTO THE COAST...AND THIS PROCESS MAY
LEAD TO NOTABLE RAIN AMOUNTS OF 1/2-1 INCH FOR THE COASTAL ZONES
OVERNIGHT. WITH THIS IN MIND WILL KEEP HIGH SCATTERED TO LIKELY
POP VALUES IN PLACE OVERNIGHT INTO DAYBREAK MONDAY...GRADUALLY
SHIFTING FOCUS INLAND...TO THE COAST IN THE NEAR TERM PERIOD.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...FORECAST MODELS ARE CONSISTENT IN SHOWING
THE MID LEVEL PATTERN TRANSITIONING FROM WHAT SEEMS LIKE A NEVER
ENDING TROUGH/WEAKNESS TO MORE OF A SOUTHWESTERLY FLOW. THIS IN
RESPONSE TO THE MASSIVE MID LEVEL LOW FINALLY OPENING UP ACROSS
THE NORTHERN PLAINS AND GETTING KICKED OUT.
AT THE SURFACE...BERMUDA HIGH PRESSURE WILL REMAIN THE MAIN PLAYER
ALTHOUGH THIS HAS LITTLE IMPACT OR CHANGE ON PREVAILING CONDITIONS
AS THIS HAS BEEN SECONDARY THE PAST FEW DAYS. POPS REMAIN ON A
DIURNAL CYCLE ALTHOUGH LOWER THROUGH THE PERIOD AS THE MID LEVEL
CATALYST IS ALL BUT REMOVED. HAVE OPTED FOR THE WARMER MAV NUMBERS
FOR TEMPERATURES THROUGH THE PERIOD.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...ONE LAST DAY OF WARM AND HUMID CONDITIONS ON
THURSDAY AS UPPER TROUGH AND SURFACE COLD FRONT BEAR DOWN ON THE
REGION FROM THE NW. SOMEWHAT SURPRISINGLY MODELS ARE GRAVITATING
TOWARDS A QUICKER SOLUTION AND THE FRONT MAY PUSH THROUGH TUESDAY
NIGHT. AHEAD OF IT SW FLOW AND HEIGHT FALLS SHOULD YIELD BETTER THAN
AVERAGE COVERAGE OF CONVECTION AND WITH A LARGELY PINNED SEABREEZE
THERE MAY BE NO PREFERRED LOCATION FOR MEASURABLE RAINFALL ESP THIS
FAR OUT IN TIME. SYSTEM WILL MOVE A LITTLE BIT SLOWLY OWING TO THE
STRENGTH OF THE DOWNSTREAM RIDGING AND RAIN CHANCES MAY LINGER INTO
FRIDAY ESPECIALLY ALONG THE COAST. MODEST COOLING AND STRONG DRYING
WILL THEN FOLLOW FOR THE WEEKEND AND SOME VERY COMFORTABLE AND
PLEASANT WEATHER APPEARS TO BE ON TAP. DAYTIME DEVIATIONS FROM CLIMO
TEMPS SHOULD BE RATHER SMALL BUT THE NIGHTS MAY TURN COOLISH DUE TO
THE DRYING. THE POST-FRONTAL HIGH MAY MOVE OFF THE COAST ON MONDAY
ALLOWING FOR AN UPTICK IN THE DEWPOINTS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...MORE SHOWERS/T-STORMS ARE EXPECTED THIS AFTN WITH
MVFR/TEMPO IFR CONDITIONS IN HEAVIER DOWNPOURS. HAVE INCLUDED
VCSH/VCTS AT ALL TERMS WITH TEMPO GROUPS ATTEMPTING TO CAPTURE THE
TIMING OF PCPN BASED ON RADAR TRENDS AND HRRR OUTPUT. VFR/MVFR
LIKELY WILL PREVAIL WITH SHORT PERIODS OF IFR VSBYS IN +SHRA. MOST
PCPN SHOULD BE NEARING THE COASTAL TERMS BY MID-AFTN...THOUGH MORE
SCT SHOWERS INLAND ARE POSSIBLE AS WELL. RAIN CHANCES RAPIDLY
DIMINISH AFTER 00Z TUESDAY. FOG/STRATUS COULD BE AN ISSUE OVERNIGHT
WITH TODAYS PERSISTENT RAINFALL...HIGHEST CONFIDENCE AT KLBT/KFLO.
EXPECT MOSTLY CLOUDY SKIES AGAIN ON TUESDAY WITH S-SW WINDS 6-10
KTS. HAVE INCLUDED VCSH ALONG THE COAST TMRW TO ACCOUNT FOR SLIGHT
PCPN CHANCES AS THE UPPER DISTURBANCE NEARS THE COAST.
EXTENDED OUTLOOK...SCATTERED SHOWERS/TSTMS WITH TEMPO MVFR ON
TUESDAY. CHANCE OF SHOWERS THURSDAY THROUGH EARLY FRIDAY. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...SUB-ADVISORY BUT LESS THAN IDEAL CONDITIONS
ON THE WATERS WITH SEAS MAINLY RUNNING 3-4 FT MOST AREAS EXCEPT
UP TO 5 FT VERY OUR WATERS OF NC. SEAS THROUGH DAYBREAK TUESDAY
WILL BE COMPRISED OF 3 FOOT SSE WAVES EVERY 6-7 SECONDS AND 1-2
FOOT ESE WAVES EVERY 10-11 SECONDS. MARINERS ARE ENCOURAGED TO
OBTAIN A RADAR BRIEFING BEFORE HEADING OUT AS SEVERAL TSTMS WILL
IMPACT THE 0-20NM COASTAL WATERS TONIGHT INTO TUESDAY MORNING.
AS FAR AS WINDS...WE CAN COUNT ON PERSISTENT SOUTHERLY FLOW OF
10-15 KT AS HIGH PRESSURE REMAINS ANCHORED OVER THE OFFSHORE
WATERS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...BERMUDA HIGH PRESSURE REMAINS THE MAIN FEATURE
FOR THE COASTAL WATERS WITH A SOUTHERLY FLOW EXPECTED TO CONTINUE
THROUGH THE PERIOD. SPEEDS WILL CONTINUE IN A 10-15 KNOT RANGE
WITH A SLIGHT INCREASE CLOSER TO THE COAST EACH LATE MORNING AND
AFTERNOON WITH THE SEA BREEZE. THE LATEST RUN OF SWAN REMAINS
CONSISTENT WITH 2-4 FOOT SEAS.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...COAST WILL LIE BETWEEN STRONG HIGH PRESSURE
ACROSS THE WEST-CENTRAL ATLANTIC AND APPROACHING COLD FRONT TO THE
NW. THE LATTER WILL BE DISPLACED EASTWARD OF THE MORE TYPICAL
BERMUDA HIGH POSITION WHICH WILL ACT TO EASE THE GRADIENT OTHERWISE
EXPECTED GIVEN SUCH A LARGE ANTICYCLONE. THE RESULTING SWELL ENERGY
COULD BRING SOME SCEC-WORTHY 5 FT SEAS TO PART OF THE AREA MAINLY
NORTHERN ZONES. COLD FRONT NOW APPEARS FASTER THAN PREVIOUSLY
THOUGHT AND SHOULD YIELD VEERING WINDS BY FRIDAY MORNING WITH A TURN
TO OFFSHORE. THE OFFSHORE FETCH AND SWELL DISRUPTION WILL LEAD TO
LOWER SEAS ON FRIDAY BUT THEN THE ENSUING PUSH OF DRY HIGH PRESSURE
COULD TIGHTEN THE GRADIENT AGAIN TO WHERE HEADLINES TOUGH TO RULE
OUT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
243 PM EDT MON MAY 20 2013
.SYNOPSIS...
A SHORTWAVE TROUGH WILL CONTINUE TO WORK THROUGH THE AREA THIS
AFTERNOON BRINGING UNSETTLED WEATHER THROUGH THIS EVENING. THE
TROUGH WILL MEANDER NORTHEASTWARD TUESDAY BEFORE MORE SETTLED
WEATHER RETURNS FOR WEDNESDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 215 PM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
TODAY: WIDESPREAD SHOWERS AND THUNDERSTORMS HAVE BROKEN OUT IN A
SERIES OF LINES ACROSS THE CWA THIS AFTERNOON IN ASSOCIATION WITH A
SHORTWAVE IMPULSE PASSING THROUGH SOUTHERN VA. FOR THE MOST
PART...THUNDER HAS BEEN LIMITED TO A SELECT FEW CELLS WITH HEAVY
SHOWERS BEING THE PRIMARY MODE OF CONVECTION. THERE ARE SEVERAL WEAK
BOUNDARIES THAT HAVE SET UP THIS AFTERNOON. THE FIRST HAS LIFTED
NORTHEAST OF THE CWA...A SECOND ALONG THE HIGHWAY 1 CORRIDOR AND A
THIRD THROUGH THE TRIAD JUST EAST OF THE I-85 CORRIDOR. THESE TWO
LINES WILL GRADUALLY PUSH EASTWARD THIS AFTERNOON BRINGING MORE
HEAVY RAIN TO AN AREA ALREADY RECEIVING 2-3 INCHES OF RAIN IN SOME
LOCATIONS. THAT BEING SAID...RAIN RATES HAVE BEEN LOW ENOUGH AND
ENOUGH TIME HAS PASSED SINCE THE LAST RAINFALL THAT FLOODING SHOULD
NOT BE A WIDESPREAD PROBLEM THIS AFTERNOON. MORE LOCALIZED FLOODING
IS POSSIBLE WITH HEAVIER SHOWERS ESPECIALLY IN URBAN AREAS AND IN
THE NORMALLY FLASHY SMALLER CREEKS. RAINFALL TOTALS THIS AFTERNOON
WILL RANGE FROM A TENTH TO A QUARTER OF AN INCH OR SO WITH LOCALLY
HEAVIER AMOUNTS IN STRONGER STORMS. TRAINING OF STORMS SHOULD NOT BE
AS BIG OF A PROBLEM THIS AFTERNOON AND EVENING AS IT WAS EARLIER
THIS MORNING.
DESPITE THE SHORTWAVE ENERGY SEVERE POTENTIAL THIS AFTERNOON STILL
LOOKS EXTREMELY LIMITED. BOTH LOW AND MID-LEVEL LAPSE RATES ARE VERY
WEAK...AS IS THE EFFECTIVE SHEAR WHICH IS LESS THAN 15 KNOTS IN ALL
LOCATIONS. ML CAPE VALUES REMAIN BETWEEN 500-1000...LIMITED BY THE
CONTINUED BROKEN TO OVERCAST SKIES THIS AFTERNOON. THAT BEING SAID A
FEW CELL MERGERS HAVE ALLOWED SOME SHOWERS TO GROW TO A LEVEL
SUPPORTIVE OF VERY SMALL HAIL AND LIGHTNING. OTHERWISE HEAVY RAIN
AND MINOR FLOODING WILL CONTINUE TO BE THE MAIN THREAT OF THE DAY.
EXPECT WINDS THIS AFTERNOON TO GENERALLY BE SOUTHWESTERLY AT 5-10
KNOTS WITH THE OCCASIONAL GUST TO 15-20 KNOTS IN SHOWERS. HIGH
TEMPERATURES TODAY WILL MOST LIKELY VARY DEPENDING ON LOCATION WITH
A FEW BREAKS IN THE CLOUDS SUPPORTIVE OF HIGHS NEAR 80 WITH THOSE
LOCATIONS MAINTAINING OVERCAST SKIES TO TOP OUT IN THE MID TO UPPER
70S.
TONIGHT: HIGH RESOLUTION CONVECTIVE ALLOWING MODELS SUPPORT SHOWER
AND THUNDERSTORM ACTIVITY ENDING IN THE WEST AFTER 00Z AND
CONTINUING THROUGH 3Z IN THE EAST. THE ACCURACY OF THESE
MODELS...ESPECIALLY THE HRRR WAS BETTER EARLIER IN THE DAY THAN IT
IS NOW BUT THE SOLUTION STILL SEEMS REASONABLE GIVEN THE LOCATION OF
THE SHORTWAVE TO THE NORTH. AFTER CONVECTION ENDS EXPECT ISSUES WITH
FOG/LOW CEILINGS AND SUB-VFR VISIBILITIES AT ALL SITES OVERNIGHT.
THIS WILL CONTINUE THROUGH SUNRISE TUESDAY. LOWS WILL BE IN THE
LOWER TO MID 60S NW TO SE.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 215 PM MONDAY...
TUESDAY STILL SHOWS THE UPPER LEVEL TROUGH LINGERING AT LEAST OVER
THE NORTHEASTERN PART OF THE STATE WITH A SURFACE HIGH OVER THE
SOUTHWESTERN ATLANTIC. THE BEST MOISTURE TRANSPORT AND PRECIPITABLE
WATER VALUES WILL SHIFT TO THE EASTERN HALF OF THE STATE TOMORROW
BUT WILL STILL HAVE THE CHANCE FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP WITH DIURNAL HEATING. ONCE AGAIN THE SEVERE THREAT WILL BE
SEVERELY HINDERED BY LACK OF GOOD LAPSE RATES...SHEAR...AND
INSTABILITY IN THE MOISTURE CONVERGENCE ZONE. THE BEST INSTABILITY
WILL BE ACROSS THE TRIAD...WHERE CLOUD COVER SHOULD BE
DECREASED...BUT ALSO WHERE THE LOW LEVELS WILL BE A BIT DRIER. IF WE
CAN GET A STORM TO FORM...THE BEST CHANCE FOR SEVERE STORMS WOULD BE
BACK ACROSS THE NORTHWEST LATE TOMORROW AFTERNOON WITH DAMAGING
WINDS THE PRIMARY THREAT...BUT ONCE AGAIN THIS IS A VERY SMALL
THREAT AND NOT EXPECTING THIS TO HAPPEN AT THIS TIME.
MODELS HAVE COME INTO A BIT BETTER AGREEMENT ON TEMPERATURES FOR
TOMORROW WITH HIGHS IN THE MID 80S EXPECTED ACROSS THE CWA AND
PERHAPS A FEW DEGREES WARMER IN THE TRIAD WHERE THERE WILL BE
GREATER INSOLATION.
TUESDAY NIGHT THINGS WILL BEGIN TO DRY OUT AS THE MESO LOW PUSHES
OFF TO THE NORTHEAST AND WEAK UPPER LEVEL RIDGING TAKES OVER.
SURFACE DEWPOINTS WILL REMAIN IN THE LOWER TO MID 60S AND LOW FOG
AND/OR STRATUS COULD ONCE AGAIN BE A PROBLEM TUESDAY NIGHT INTO
WEDNESDAY MORNING. EXPECT LOWS IN THE MIDDLE 60S TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 240 PM MONDAY...
FOR WEDNESDAY...WEAK SHORTWAVE RIDGING WILL BUILD OVER THE AREA...
WHILE AT THE SURFACE...THE BERMUDA HIGH WILL RIDGE WESTWARD INTO THE
CAROLINAS. ALL OF THIS WILL TRANSLATE TO AN EVEN FURTHER DECREASE IN
PRECIP COVERAGE. HOWEVER...SUFFICIENT MOISTURE WILL STILL BE IN
PLACE OVER THE REGION...WITH PWAT VALUES HOVERING NEAR 1.5 INCHES OR
SO. THEREFORE...AM STILL EXPECTING TO SEE WIDELY SCATTERED TO
SCATTERED DIURNALLY DRIVEN CONVECTION...WITH THE HIGHEST CHANCES
BEING ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA. HIGHS ONCE
AGAIN SHOULD BE IN THE MID/UPPER 80S...WITH OVERNIGHT LOWS IN THE
MID/UPPER 60S.
SHOWER AND THUNDERSTORM COVERAGE SHOULD BEGIN TO INCREASE ONCE AGAIN
BY THE END OF THE WORK WEEK AS THE MID/UPPER LEVEL RIDGE SHIFTS
OFFSHORE AHEAD OF OUR NEXT MID/UPPER LEVEL TROUGH AND ASSOCIATED
COLD FRONT. MODELS REMAIN IN GENERAL AGREEMENT WITH BRINGING THE
FRONT THROUGH THE FORECAST AREA LATE THURSDAY NIGHT/EARLY FRIDAY.
THEREFORE...WILL SHOW POPS HIGHEST POPS CONCENTRATED DURING THE
THURSDAY/EARLY FRIDAY TIME FRAME...THEN DECREASING FROM WEST TO EAST
THROUGHOUT THE DAY ON FRIDAY. BULK SHEAR VALUES WILL INCREASE TO
AROUND 25 KNOTS OR SO...THEREFORE BETTER STORM ORGANIZATION IS
EXPECTED...HOWEVER THE BEST UPPER LEVEL FORCING WILL PASS WELL TO
OUR NORTH. THEREFORE...EVEN THOUGH AN ISOLATED SEVERE STORM CANNOT
BE COMPLETELY RULED OUT...THE OVERALL THREAT REMAINS LOW AT THIS
TIME. WITH THE INCREASED PRECIP CHANCES/CLOUDS ON THURSDAY AND
FRIDAY...TEMPS WILL MOSTLY BE IN THE LOW/MID 80S.
IT STILL APPEARS THE WEEKEND AND INTO EARLY NEXT WEEK WILL BE DRY AS
HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING FRONT. SLIGHTLY COOLER
TEMPS ARE EXPECTED DURING THIS TIME FRAME...GENERALLY THE UPPER 70S
TO LOWER 80S...WITH OVERNIGHT LOWS IN THE 50S.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 115 PM MONDAY...
24 HOUR TAF PERIOD:
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL PREVAIL THIS
AFTERNOON ACROSS THE CWA AT ALL TERMINALS. CURRENTLY RADAR SHOWS
SHORTWAVE CURRENTLY MOVING ACROSS THE TRIAD WITH STRONGER CELLS ON
THE EASTERN SIDE WITH LINGERING SHOWERS TO THE WEST. FOR THE TRIAD
STRONGEST SHOWERS AND THUNDERSTORMS MOST LIKELY MOVING THROUGH NOW
THROUGH THE NEXT COUPLE OF HOURS AND DOWN TRENDING TO MOSTLY LIGHT
SHOWERS THEREAFTER. FURTHER TO THE EAST CONDITIONS SHOULD REMAIN
MORE FAVORABLE FOR HEAVIER SHOWERS AND THUNDERSTORMS THROUGH EARLY
EVENING. EXPECT CEILINGS TO BOUNCE BETWEEN VFR AND MVFR AND SINKING
OCCASIONALLY TO IFR IN THE STRONGER CELLS. WILL COVER THIS WITH A
TEMPO GROUP IN THE TAFS WITH VFR/MVFR PREVAILING. WINDS WILL REMAIN
GENERALLY SOUTHWESTERLY AT 5-10 KNOTS WITH OCCASIONAL GUSTS OF 15-20
IN HEAVY SHOWERS.
AFTER PRECIPITATION WINDS DOWN TONIGHT EXPECT SOME LOW
CEILINGS/VISIBILITIES...GENERALLY AFTER 3Z. EXPECT SOME FOG IN THE
WEST WITH MORE OF A LOW STRATUS SITUATION FURTHER TO THE EAST.
CONDITIONS SHOULD REMAIN SUB VFR EVERYWHERE UNTIL 15Z WHEN VFR
CEILINGS AND VISIBILITIES SHOULD RETURN. ALTHOUGH CONDITIONS WILL BE
IMPROVING AND GENERALLY DRYING...THE MESO-LOW WILL LINGER OVERHEAD
KEEPING THE CHANCE FOR SHOWERS ALIVE THROUGH THE END OF THE TAF
PERIOD.
LONG TERM:
LOW STRATUS AND FOG ARE EXPECTED TO RETURN TUESDAY NIGHT INTO
WEDNESDAY. WEDNESDAY WILL BE THE DRIEST DAY BUT WILL STILL HAVE THE
CHANCE FOR DIURNAL SHOWERS AND STORMS. THURSDAY AND THURSDAY NIGHT
WILL FEATURE THE PASSAGE OF A COLD FRONT AND A RETURN TO SUB-VFR
CONDITIONS. VFR CONDITIONS WILL GRADUALLY RETURN TO THE AREA ON
FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...ELLIS
LONG TERM...KRR
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
221 PM EDT MON MAY 20 2013
.SYNOPSIS...
A SHORTWAVE TROUGH WILL CONTINUE TO WORK THROUGH THE AREA THIS
AFTERNOON BRINGING UNSETTLED WEATHER THROUGH THIS EVENING. THE
TROUGH WILL MEANDER NORTHEASTWARD TUESDAY BEFORE MORE SETTLED
WEATHER RETURNS FOR WEDNESDAY.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 215 PM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
TODAY: WIDESPREAD SHOWERS AND THUNDERSTORMS HAVE BROKEN OUT IN A
SERIES OF LINES ACROSS THE CWA THIS AFTERNOON IN ASSOCIATION WITH A
SHORTWAVE IMPULSE PASSING THROUGH SOUTHERN VA. FOR THE MOST
PART...THUNDER HAS BEEN LIMITED TO A SELECT FEW CELLS WITH HEAVY
SHOWERS BEING THE PRIMARY MODE OF CONVECTION. THERE ARE SEVERAL WEAK
BOUNDARIES THAT HAVE SET UP THIS AFTERNOON. THE FIRST HAS LIFTED
NORTHEAST OF THE CWA...A SECOND ALONG THE HIGHWAY 1 CORRIDOR AND A
THIRD THROUGH THE TRIAD JUST EAST OF THE I-85 CORRIDOR. THESE TWO
LINES WILL GRADUALLY PUSH EASTWARD THIS AFTERNOON BRINGING MORE
HEAVY RAIN TO AN AREA ALREADY RECEIVING 2-3 INCHES OF RAIN IN SOME
LOCATIONS. THAT BEING SAID...RAIN RATES HAVE BEEN LOW ENOUGH AND
ENOUGH TIME HAS PASSED SINCE THE LAST RAINFALL THAT FLOODING SHOULD
NOT BE A WIDESPREAD PROBLEM THIS AFTERNOON. MORE LOCALIZED FLOODING
IS POSSIBLE WITH HEAVIER SHOWERS ESPECIALLY IN URBAN AREAS AND IN
THE NORMALLY FLASHY SMALLER CREEKS. RAINFALL TOTALS THIS AFTERNOON
WILL RANGE FROM A TENTH TO A QUARTER OF AN INCH OR SO WITH LOCALLY
HEAVIER AMOUNTS IN STRONGER STORMS. TRAINING OF STORMS SHOULD NOT BE
AS BIG OF A PROBLEM THIS AFTERNOON AND EVENING AS IT WAS EARLIER
THIS MORNING.
DESPITE THE SHORTWAVE ENERGY SEVERE POTENTIAL THIS AFTERNOON STILL
LOOKS EXTREMELY LIMITED. BOTH LOW AND MID-LEVEL LAPSE RATES ARE VERY
WEAK...AS IS THE EFFECTIVE SHEAR WHICH IS LESS THAN 15 KNOTS IN ALL
LOCATIONS. ML CAPE VALUES REMAIN BETWEEN 500-1000...LIMITED BY THE
CONTINUED BROKEN TO OVERCAST SKIES THIS AFTERNOON. THAT BEING SAID A
FEW CELL MERGERS HAVE ALLOWED SOME SHOWERS TO GROW TO A LEVEL
SUPPORTIVE OF VERY SMALL HAIL AND LIGHTNING. OTHERWISE HEAVY RAIN
AND MINOR FLOODING WILL CONTINUE TO BE THE MAIN THREAT OF THE DAY.
EXPECT WINDS THIS AFTERNOON TO GENERALLY BE SOUTHWESTERLY AT 5-10
KNOTS WITH THE OCCASIONAL GUST TO 15-20 KNOTS IN SHOWERS. HIGH
TEMPERATURES TODAY WILL MOST LIKELY VARY DEPENDING ON LOCATION WITH
A FEW BREAKS IN THE CLOUDS SUPPORTIVE OF HIGHS NEAR 80 WITH THOSE
LOCATIONS MAINTAINING OVERCAST SKIES TO TOP OUT IN THE MID TO UPPER
70S.
TONIGHT: HIGH RESOLUTION CONVECTIVE ALLOWING MODELS SUPPORT SHOWER
AND THUNDERSTORM ACTIVITY ENDING IN THE WEST AFTER 00Z AND
CONTINUING THROUGH 3Z IN THE EAST. THE ACCURACY OF THESE
MODELS...ESPECIALLY THE HRRR WAS BETTER EARLIER IN THE DAY THAN IT
IS NOW BUT THE SOLUTION STILL SEEMS REASONABLE GIVEN THE LOCATION OF
THE SHORTWAVE TO THE NORTH. AFTER CONVECTION ENDS EXPECT ISSUES WITH
FOG/LOW CEILINGS AND SUB-VFR VISIBILITIES AT ALL SITES OVERNIGHT.
THIS WILL CONTINUE THROUGH SUNRISE TUESDAY. LOWS WILL BE IN THE
LOWER TO MID 60S NW TO SE.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 215 PM MONDAY...
TUESDAY STILL SHOWS THE UPPER LEVEL TROUGH LINGERING AT LEAST OVER
THE NORTHEASTERN PART OF THE STATE WITH A SURFACE HIGH OVER THE
SOUTHWESTERN ATLANTIC. THE BEST MOISTURE TRANSPORT AND PRECIPITABLE
WATER VALUES WILL SHIFT TO THE EASTERN HALF OF THE STATE TOMORROW
BUT WILL STILL HAVE THE CHANCE FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP WITH DIURNAL HEATING. ONCE AGAIN THE SEVERE THREAT WILL BE
SEVERELY HINDERED BY LACK OF GOOD LAPSE RATES...SHEAR...AND
INSTABILITY IN THE MOISTURE CONVERGENCE ZONE. THE BEST INSTABILITY
WILL BE ACROSS THE TRIAD...WHERE CLOUD COVER SHOULD BE
DECREASED...BUT ALSO WHERE THE LOW LEVELS WILL BE A BIT DRIER. IF WE
CAN GET A STORM TO FORM...THE BEST CHANCE FOR SEVERE STORMS WOULD BE
BACK ACROSS THE NORTHWEST LATE TOMORROW AFTERNOON WITH DAMAGING
WINDS THE PRIMARY THREAT...BUT ONCE AGAIN THIS IS A VERY SMALL
THREAT AND NOT EXPECTING THIS TO HAPPEN AT THIS TIME.
MODELS HAVE COME INTO A BIT BETTER AGREEMENT ON TEMPERATURES FOR
TOMORROW WITH HIGHS IN THE MID 80S EXPECTED ACROSS THE CWA AND
PERHAPS A FEW DEGREES WARMER IN THE TRIAD WHERE THERE WILL BE
GREATER INSOLATION.
TUESDAY NIGHT THINGS WILL BEGIN TO DRY OUT AS THE MESO LOW PUSHES
OFF TO THE NORTHEAST AND WEAK UPPER LEVEL RIDGING TAKES OVER.
SURFACE DEWPOINTS WILL REMAIN IN THE LOWER TO MID 60S AND LOW FOG
AND/OR STRATUS COULD ONCE AGAIN BE A PROBLEM TUESDAY NIGHT INTO
WEDNESDAY MORNING. EXPECT LOWS IN THE MIDDLE 60S TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...
UPPER LEVEL RIDGE BUILDS BRIEFLY OVER THE AREA ON WEDNESDAY... WHICH
SHOULD DIMINISH THE COVERAGE OF CONVECTION... ALTHOUGH DIURNALLY
DRIVEN THUNDERSTORMS CONTINUE TO BE POSSIBLE WITH THE MOIST AIRMASS
OVER THE AREA. PWATS WILL REMAIN NEAR 1.5... 2 STANDARD DEVIATIONS
ABOVE NORMAL FOR THIS TIME OF YEAR. WITH WEAK SHEAR... EXPECTING
PULSE TYPE STORMS. HIGHS IN THE MID 80S... LOWS MID 60S.
UPPER LEVEL RIDGE SHIFTS OFFSHORE THURSDAY. AFTERNOON THUNDERSTORMS
CONTINUE TO BE POSSIBLE IN THE AFTERNOON THURSDAY AS PWATS REMAIN
ABOVE NORMAL. BULK SHEAR INCREASES TO 25 TO 30 KTS... WHICH MAY
SUPPORT SOME MULTICELL ORGANIZATION. THICKNESSES REMAIN NEAR TO
SLIGHTLY ABOVE AVERAGE THURSDAY AND FRIDAY... FAVORING TEMPERATURES
CONTINUING TO A BE A FEW DEGREES ABOVE NORMAL... WITH HIGHS IN THE
80S AND LOWS IN THE UPPER 60S. THE TROUGH OVER THE MIDWEST MOVES
EASTWARD ON THURSDAY... AND THE ATTENDANT COLD FRONT PUSHES ACROSS
THE REGION FRIDAY. TIMING HAS TRENDED FASTER DURING TODAYS MODEL
RUNS... WITH THE FRONT MAKING IT THROUGH THE AREA EARLY FRIDAY...
AND TO THE CAROLINA COAST FRIDAY MORNING. STRONGEST DYNAMIC FORCING
REMAINS NORTH OVER NEW ENGLAND... AND WITH THE TIMING NOW LOOKING
MORE DIURNALLY UNFAVORABLE... DO NOT EXPECT A THREAT OF SEVERE
WEATHER.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 115 PM MONDAY...
24 HOUR TAF PERIOD:
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL PREVAIL THIS
AFTERNOON ACROSS THE CWA AT ALL TERMINALS. CURRENTLY RADAR SHOWS
SHORTWAVE CURRENTLY MOVING ACROSS THE TRIAD WITH STRONGER CELLS ON
THE EASTERN SIDE WITH LINGERING SHOWERS TO THE WEST. FOR THE TRIAD
STRONGEST SHOWERS AND THUNDERSTORMS MOST LIKELY MOVING THROUGH NOW
THROUGH THE NEXT COUPLE OF HOURS AND DOWN TRENDING TO MOSTLY LIGHT
SHOWERS THEREAFTER. FURTHER TO THE EAST CONDITIONS SHOULD REMAIN
MORE FAVORABLE FOR HEAVIER SHOWERS AND THUNDERSTORMS THROUGH EARLY
EVENING. EXPECT CEILINGS TO BOUNCE BETWEEN VFR AND MVFR AND SINKING
OCCASIONALLY TO IFR IN THE STRONGER CELLS. WILL COVER THIS WITH A
TEMPO GROUP IN THE TAFS WITH VFR/MVFR PREVAILING. WINDS WILL REMAIN
GENERALLY SOUTHWESTERLY AT 5-10 KNOTS WITH OCCASIONAL GUSTS OF 15-20
IN HEAVY SHOWERS.
AFTER PRECIPITATION WINDS DOWN TONIGHT EXPECT SOME LOW
CEILINGS/VISIBILITIES...GENERALLY AFTER 3Z. EXPECT SOME FOG IN THE
WEST WITH MORE OF A LOW STRATUS SITUATION FURTHER TO THE EAST.
CONDITIONS SHOULD REMAIN SUB VFR EVERYWHERE UNTIL 15Z WHEN VFR
CEILINGS AND VISIBILITIES SHOULD RETURN. ALTHOUGH CONDITIONS WILL BE
IMPROVING AND GENERALLY DRYING...THE MESO-LOW WILL LINGER OVERHEAD
KEEPING THE CHANCE FOR SHOWERS ALIVE THROUGH THE END OF THE TAF
PERIOD.
LONG TERM:
LOW STRATUS AND FOG ARE EXPECTED TO RETURN TUESDAY NIGHT INTO
WEDNESDAY. WEDNESDAY WILL BE THE DRIEST DAY BUT WILL STILL HAVE THE
CHANCE FOR DIURNAL SHOWERS AND STORMS. THURSDAY AND THURSDAY NIGHT
WILL FEATURE THE PASSAGE OF A COLD FRONT AND A RETURN TO SUB-VFR
CONDITIONS. VFR CONDITIONS WILL GRADUALLY RETURN TO THE AREA ON
FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...ELLIS
LONG TERM...SEC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT MON MAY 20 2013
.SYNOPSIS...
A DISTURBANCE ALOFT MOVING ACROSS THE AREA WILL MAINTAIN SHOWERS AND
THUNDERSTORMS THROUGH TUESDAY. DRIER AND WARMER WEATHER IS EXPECTED
MID WEEK. A COLD FRONT IS EXPECTED TO APPROACH AND CROSS THE REGION
ON FRIDAY...BRINGING DRIER AND SLIGHTLY COOLER WEATHER INTO THE NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1037 AM MONDAY...LATEST RADAR TRENDS SHOW THE AXIS OF HEAVIEST
RAINFALL INLAND IS SHIFTING EAST AND AWAY FROM AREAS THAT HAVE
RECEIVED PLENTIFUL TO EXCESSIVE RAINFALL. THIS EASTWARD PROGRESS WILL
HELP ALLEVIATE THE NEAR TERM FLOODING POTENTIAL...AND CURRENTLY NO
FLOOD WARNING OR ADVISORY PRODUCTS ARE IN EFFECT. THE FLOOD WARNING
FOR MARLBORO COUNTY LAST NIGHT AND THIS MORNING HAD VERIFICATION
WITH FLOODING OF MAIN ST IN BENNETTSVILLE WHERE EARLIER...WATER HAD
RISEN UPON THE ADJACENT SIDEWALKS. CURRENT ACTIVITY WILL WANE OVER
THE WATERS AS LOW-LEVEL BUOYANCY WEAKENS. THE AFTERNOON FOCUS WILL
BE IN FOLLOWING THE TRENDS OF THE MAIN AXIS OF RAINFALL INLAND
EDGING SLOWLY TOWARD THE COAST. OUR CENTRAL AND EVENTUALLY THE
EASTERN ZONES STAND TO RECEIVE AN INCH OR MORE OF RAIN AS THE SLOW
EAST COMPONENT OF THE STEERING FLOW PREVAILS. PORTIONS OF THE
PREVIOUS DISCUSSION FOLLOWS.
A WEAK UPPER LEVEL DISTURBANCE WILL ELONGATE NORTH-TO-SOUTH TODAY
ACROSS THE CENTRAL CAROLINAS...EVENTUALLY CLEAVING INTO TWO
INDIVIDUAL PIECES TONIGHT. CYCLONIC FLOW SURROUNDING THIS FEATURE
ALOFT IS VERY WEAK AND STORM CELL MOTION IS ANTICIPATED TO BE SLOW
TODAY. WITH PRECIPITABLE WATER VALUES NOW IN THE SUMMER/TROPICAL
RANGE OF 1.6 TO 1.8 INCHES AND MODEL FORECAST SOUNDINGS SHOWING
ALMOST 10000 FEET OF WARM CONVECTIVE CLOUD DEPTH (LCL AROUND 2500 FT
VERSUS AN ENVIRONMENTAL FREEZING LEVEL OF 12500 FT) THERE IS A
GROWING POTENTIAL FOR HEAVY RAINFALL...PERHAPS EVEN EXCESSIVE
RAINFALL AND FLOODING LATER TODAY. I DO NOT PLAN TO ISSUE A FLOOD
WATCH...BUT WILL INCLUDE HEAVY RAIN MENTION IN THE FORECAST GRIDS
AND HAZARDOUS WX OUTLOOK.
A STABILIZING BOUNDARY LAYER AND A WEAKENING UPPER LEVEL DISTURBANCE
TONIGHT SHOULD PRODUCE A RAPID DECREASE IN COVERAGE OF SHOWERS.
SOUTH WINDS MAY STILL ADVECT NOCTURNAL MARINE CONVECTION ONSHORE SO
THE HIGHEST POPS (30-40 PERCENT) WILL REMAIN OVERNIGHT NEAR THE
BEACHES...WITH LESSER CHANCES INLAND. LOWS SHOULD FALL TO 66-69 FOR
MOST AREAS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...HIGH PRESSURE OFFSHORE WILL CONTINUE ITS
INFLUENCE ACROSS THE CAROLINAS...BUT A DECREASING TREND IN
CONVECTION WITH WARMING TEMPS IS EXPECTED THROUGH THE SHORT TERM.
BUILDING 1000-500MB THICKNESSES AND SOME WEAK NVA BEHIND A DEPARTING
SHORTWAVE WILL CREATE SUBSIDENCE WITH INCREASED DRYING THROUGH THE
COLUMN. FORECAST PROFILES SUGGEST SIGNIFICANT DRY AIR ABOVE
800MB...AND THIS IS ECHOED IN PWATS FALLING TO 1.25 INCHES BY
WEDNESDAY. THIS WILL TEND TO INHIBIT MUCH IN THE WAY OF
CONVECTION...BUT WITH TEMPS RISING WELL INTO THE 80S...ISOLATED
CONVECTION WILL REMAIN POSSIBLE...ESPECIALLY TUESDAY. WILL CONTINUE
LOW-CHC POP TUESDAY AND SCHC WEDNESDAY...BUT WOULD NOT BE SURPRISED
IF WED ENDS UP BEING DRY ACROSS THE CWA.
TEMPS WILL RESPOND TO BULGING HEIGHTS...RISING FROM THE LOW/MID 80S
TUESDAY INTO THE MID/UPR 80S WEDNESDAY. LOWS WILL REMAIN WELL ABOVE
NORMAL FOR MID-MAY THANKS TO CONTINUED SOUTHERLY WINDS...FALLING
ONLY INTO THE UPPER 60S BOTH NIGHTS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...PATTERN CHANGE TO OCCUR DURING THE EXTENDED AS
COLD FRONT CROSSES THE AREA FRIDAY...USHERING IN A MUCH DRIER
AIRMASS TO THE CAROLINAS.
BERMUDA HIGH AND MID LEVEL RIDGING WILL PERSIST AT THE START OF THE
PERIOD...BUT FULL LATITUDE TROUGH WILL BEGIN TO DISPLACE THE RIDGE
CAUSING INCREASED CONVECTIVE CHANCES AND SLIGHTLY COOLER TEMPS. GFS
HAS SPED UP TIMING OF FRONT CONSIDERABLY...WHICH DOESN`T MAKE A LOT
OF SENSE BASED OFF RESTRICTIVE ANTECEDENT FLOW OF THE UPPER
PATTERN...AND FAVOR THE SLOWER CMC/ECMWF WHICH HAS THE FROPA
OCCURRING FRIDAY AFTN. THIS WILL SUPPORT ANOTHER DAY OF CONVECTION
AHEAD OF THE FRONT...BUT DRYING WILL OCCUR RAPIDLY BEHIND IT AS HIGH
PRESSURE BUILDS IN FROM THE NW. WHILE OVERALL TEMPERATURE CHANGE
WILL BE MINIMAL...WITH TEMPS ONLY A FEW DEGREES COOLER DURING THE
WKND...IT WILL BE MUCH DRIER...AND A BEAUTIFUL WKND APPEARS TO BE IN
STORE FOR THE AREA WITH TEMPS SLIGHTLY BELOW CLIMO.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...MORE SHOWERS/T-STORMS ARE EXPECTED THIS AFTN WITH
MVFR/TEMPO IFR CONDITIONS IN HEAVIER DOWNPOURS. HAVE INCLUDED
VCSH/VCTS AT ALL TERMS WITH TEMPO GROUPS ATTEMPTING TO CAPTURE THE
TIMING OF PCPN BASED ON RADAR TRENDS AND HRRR OUTPUT. VFR/MVFR
LIKELY WILL PREVAIL WITH SHORT PERIODS OF IFR VSBYS IN +SHRA. MOST
PCPN SHOULD BE NEARING THE COASTAL TERMS BY MID-AFTN...THOUGH MORE
SCT SHOWERS INLAND ARE POSSIBLE AS WELL. RAIN CHANCES RAPIDLY
DIMINISH AFTER 00Z TUESDAY. FOG/STRATUS COULD BE AN ISSUE OVERNIGHT
WITH TODAYS PERSISTENT RAINFALL...HIGHEST CONFIDENCE AT KLBT/KFLO.
EXPECT MOSTLY CLOUDY SKIES AGAIN ON TUESDAY WITH S-SW WINDS 6-10
KTS. HAVE INCLUDED VCSH ALONG THE COAST TMRW TO ACCOUNT FOR SLIGHT
PCPN CHANCES AS THE UPPER DISTURBANCE NEARS THE COAST.
EXTENDED OUTLOOK...SCATTERED SHOWERS/TSTMS WITH TEMPO MVFR ON
TUESDAY. CHANCE OF SHOWERS THURSDAY THROUGH EARLY FRIDAY. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1037 AM MONDAY...THE OVERALL PATTERN WILL BE LITTLE CHANGED
FROM YESTERDAY WITH SURFACE HIGH PRESSURE REMAINING ANCHORED ALMOST
1000 MILES EAST OF CAPE HATTERAS AND LOW PRESSURE MOVING SLOWLY
ACROSS THE NORTHERN PLAINS STATES. THIS WILL ENSURE A LIGHT TO
MODERATE SOUTH WIND ACROSS THE CAROLINA COASTAL WATERS TODAY AND
TONIGHT.
SHOWERS AND EMBEDDED THUNDERSTORMS THIS MORNING SHOULD DECREASE IN
COVERAGE THIS AFTERNOON AS THE SEABREEZE CIRCULATION DEVELOPS...BUT
ANOTHER ROUND OF SCATTERED SHOWER ACTIVITY MAY DEVELOP TONIGHT. HIGH
MOISTURE CONTENT OF THE ATMOSPHERE MEANS HEAVY RAINFALL AND MARINE
VISIBILITY RESTRICTIONS ARE THE LARGEST THREATS.
SEAS CURRENTLY RANGE FROM 3-4 FT AT THE CAPE FEAR AREA BUOYS IN A
COMBINATION OF SOUTHEAST SWELL AND SOUTH WIND WAVES.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...RETURN FLOW AROUND BERMUDA HIGH PRESSURE
OFFSHORE CONTINUES THROUGH THE SHORT TERM...WITH SOUTHERLY WINDS OF
10-15 KTS COMMON EACH DAY. SEAS OF 2-3 FT TUESDAY WILL RISE TO 2-4
FT WEDNESDAY THANKS TO SLIGHTLY HIGHER WINDS. WHILE A DEAMPLIYFING
SE SWELL WILL BE PRESENT WITHIN THE WAVE SPECTRUM...SEAS WILL BE
PRIMARILY DERIVED FROM A SOUTHERLY 5-6 SEC WIND WAVE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...SOUTHERLY WINDS AROUND 15 KTS TO START THE
PERIOD WILL VEER THROUGH THURSDAY TO THE W/SW AS A COLD FRONT
APPROACHES FROM THE NW. THIS FRONT WILL CROSS THE WATERS DURING
FRIDAY...TURNING WINDS QUICKLY TO THE WEST FRIDAY EVE WITH DECREASED
SPEEDS BEFORE WINDS INCREASE FROM THE NORTH FRIDAY NIGHT. SEAS WILL
RISE TO 3-5 FT THURSDAY NIGHT AHEAD OF THE COLD FRONT BEFORE FALLING
BACK TO 2-4 FT LATE FRIDAY THANKS TO THE OFFSHORE COMPONENT OF THE
WIND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA/MJC
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...BJR/MJC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
115 PM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAKENING MID AND UPPER LEVEL TROUGH WILL SETTLE OVER CENTRAL
NORTH CAROLINA TODAY BRINGING MORE UNSETTLED CONDITIONS WITH LOCALLY
HEAVY RAIN. THE TROUGH WILL GRADUALLY MOVE TO NEAR THE COAST ON
TUESDAY REDUCING THE THREAT OF LOCALLY HEAVY RAIN.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 930 AM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
AN UPPER LEVEL MESO-LOW AND ASSOCIATED 500 MB TROUGH WILL LINGER
OVER THE SOUTHEASTERN COASTAL STATES TODAY...WHILE AT THE
SURFACE...RETURN FLOW AROUND A HIGH OF THE MID-ATLANTIC COAST WILL
KEEP LIGHT GRADUAL UPSLOPE FLOW OVER CENTRAL NORTH CAROLINA. CURRENT
RUN OF THE NAM SHOWS GOOD MOISTURE TRANSPORT AND CONVERGENCE OVER
THE CENTRAL AND EASTERN PORTIONS OF THE STATE. CURRENT SPC
MESO-ANALYSIS SHOWS PW VALUES BETWEEN 1.6 AND 1.8 INCHES ACROSS THE
CWA. THIS PATTERN SHOULD HOLD FOR MUCH OF THE DAY AS CURRENT AXIS OF
PRECIPITATION OVER THE CENTRAL PORTION OF THE CWA GRADUALLY MOVES
EASTWARD INTO THE I-95 CORRIDOR. FURTHER TO THE WEST A SHORTWAVE
TROUGH IS EXPECTED TO SWING THROUGH THE WESTERN HALF OF THE STATE
PROVIDING A LITTLE MORE FORCING FOR AFTERNOON SHOWERS AND
THUNDERSTORMS. HRRR MODEL INDICATES THAT SOME HEAVIER SHOWERS WILL
DEVELOP AND MOVE INTO SOUTHWESTERN COUNTIES THIS AFTERNOON. MUCH OF
THE CENTRAL PORTION OF THE CWA HAS RECEIVED SIGNIFICANT RAINFALL
OVER THE PAST 24 HOURS BUT RAINFALL RATES HAVE BEEN LOW ENOUGH THAT
ANY FLOODING PROBLEMS HAVE BEEN NON-EXISTENT AT THIS TIME. WE WILL
CONTINUE TO MONITOR URBAN AREAS AND SMALL STREAMS FOR FLOODING
ACTIVITY WITH CONTINUED RAINFALL THIS AFTERNOON.
AT THIS HOUR MUCH OF THE AREA IS OVERCAST...BUT SOME BREAKS IN THE
CLOUDS COULD PROVIDE SOME DIFFERENTIAL HEATING BOUNDARIES THIS
AFTERNOON. WHILE SHOWERS AND THE OCCASIONAL THUNDERSTORM WILL BE
PROBABLE THIS AFTERNOON...THE LIKELIHOOD THAT ANY OF THESE STORMS
BECOMES SEVERE IS RELATIVELY LOW. WHILE THERE IS SOME
INSTABILITY...EFFECTIVE SHEAR IS VIRTUALLY NON-EXISTENT AND LAPSE
RATES ARE MODEST AT BEST. NO DCAPE TO WORK WITH MAKES SEVERE WINDS
VERY UNLIKELY. EXPECT LOWER CEILINGS TO CONTINUE TO PREVAIL THROUGH
THE MORNING AND INTO THE AFTERNOON ALSO HINDERING INSTABILITY.
DESPITE THIS...HIGHS SHOULD STILL REACH NEAR THE 80 DEGREE MARK THIS
AFTERNOON AS SOUTHWESTERLY FLOW AND WARM AIR ADVECTION HELP ELEVATE
HIGHS TODAY. -ELLIS
SHOWERS AND SCATTERED THUNDERSTORMS SHOULD DIMINISH WITH LOSS OF
HEATING THIS EVENING. WITH THE BASE OF THE TROUGH STILL OVER THE
REGION... WE WILL CONTINUE TO CARRY LOW END POPS AND QPF UNDER 0.25.
LOWS 65-70. STRATUS AND FOG WILL AGAIN BE PROBLEMATIC ESPECIALLY
09Z-13Z/TUE. -BADGETT
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 250 AM MONDAY...
A CONTINUED WEAKENING TREND WITH THE TROUGH AND A GRADUAL SHIFT
EASTWARD WILL MEAN MORE SCATTERED AND LESS CONCENTRATED CONVECTIVE
RAINFALL ON TUESDAY AFTERNOON AND EVENING. SEVERAL MODEL SOLUTIONS
INDICATE THE SUBTROPICAL RIDGE EXTENDING WESTWARD FROM THE WESTERN
ATLANTIC OVER PORTIONS OF NC. AFTER A START TO THE DAY WITH LOW
STRATUS AND AREAS OF FOG... PARTLY SUNNY SKIES ARE EXPECTED. HIGHS
SHOULD REBOUND INTO THE LOWER TO MID 80S. HOWEVER... DEW POINTS WILL
STILL BE IN THE MID TO UPPER 60S. THE COOLER MET/NAM GUIDANCE LOOKS
MORE IN LINE WITH THE CURRENT EXPECTATIONS WITH THE SSW FLOW AND
PLENTY OF LOW LEVEL MOISTURE AND BROKEN AFTERNOON CLOUDINESS. WIDELY
SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. THIS
ACTIVITY WILL DIMINISH TUESDAY EVENING WITH LOSS OF HEATING. PARTLY
CLOUDY SKIES WITH AREAS OF FOG AGAIN EXPECTED LATE AT NIGHT. LOWS IN
THE MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...
UPPER LEVEL RIDGE BUILDS BRIEFLY OVER THE AREA ON WEDNESDAY... WHICH
SHOULD DIMINISH THE COVERAGE OF CONVECTION... ALTHOUGH DIURNALLY
DRIVEN THUNDERSTORMS CONTINUE TO BE POSSIBLE WITH THE MOIST AIRMASS
OVER THE AREA. PWATS WILL REMAIN NEAR 1.5... 2 STANDARD DEVIATIONS
ABOVE NORMAL FOR THIS TIME OF YEAR. WITH WEAK SHEAR... EXPECTING
PULSE TYPE STORMS. HIGHS IN THE MID 80S... LOWS MID 60S.
UPPER LEVEL RIDGE SHIFTS OFFSHORE THURSDAY. AFTERNOON THUNDERSTORMS
CONTINUE TO BE POSSIBLE IN THE AFTERNOON THURSDAY AS PWATS REMAIN
ABOVE NORMAL. BULK SHEAR INCREASES TO 25 TO 30 KTS... WHICH MAY
SUPPORT SOME MULTICELL ORGANIZATION. THICKNESSES REMAIN NEAR TO
SLIGHTLY ABOVE AVERAGE THURSDAY AND FRIDAY... FAVORING TEMPERATURES
CONTINUING TO A BE A FEW DEGREES ABOVE NORMAL... WITH HIGHS IN THE
80S AND LOWS IN THE UPPER 60S. THE TROUGH OVER THE MIDWEST MOVES
EASTWARD ON THURSDAY... AND THE ATTENDANT COLD FRONT PUSHES ACROSS
THE REGION FRIDAY. TIMING HAS TRENDED FASTER DURING TODAYS MODEL
RUNS... WITH THE FRONT MAKING IT THROUGH THE AREA EARLY FRIDAY...
AND TO THE CAROLINA COAST FRIDAY MORNING. STRONGEST DYNAMIC FORCING
REMAINS NORTH OVER NEW ENGLAND... AND WITH THE TIMING NOW LOOKING
MORE DIURNALLY UNFAVORABLE... DO NOT EXPECT A THREAT OF SEVERE
WEATHER.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 115 PM MONDAY...
24 HOUR TAF PERIOD:
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL PREVAIL THIS
AFTERNOON ACROSS THE CWA AT ALL TERMINALS. CURRENTLY RADAR SHOWS
SHORTWAVE CURRENTLY MOVING ACROSS THE TRIAD WITH STRONGER CELLS ON
THE EASTERN SIDE WITH LINGERING SHOWERS TO THE WEST. FOR THE TRIAD
STRONGEST SHOWERS AND THUNDERSTORMS MOST LIKELY MOVING THROUGH NOW
THROUGH THE NEXT COUPLE OF HOURS AND DOWN TRENDING TO MOSTLY LIGHT
SHOWERS THEREAFTER. FURTHER TO THE EAST CONDITIONS SHOULD REMAIN
MORE FAVORABLE FOR HEAVIER SHOWERS AND THUNDERSTORMS THROUGH EARLY
EVENING. EXPECT CEILINGS TO BOUNCE BETWEEN VFR AND MVFR AND SINKING
OCCASIONALLY TO IFR IN THE STRONGER CELLS. WILL COVER THIS WITH A
TEMPO GROUP IN THE TAFS WITH VFR/MVFR PREVAILING. WINDS WILL REMAIN
GENERALLY SOUTHWESTERLY AT 5-10 KNOTS WITH OCCASIONAL GUSTS OF 15-20
IN HEAVY SHOWERS.
AFTER PRECIPITATION WINDS DOWN TONIGHT EXPECT SOME LOW
CEILINGS/VISIBILITIES...GENERALLY AFTER 3Z. EXPECT SOME FOG IN THE
WEST WITH MORE OF A LOW STRATUS SITUATION FURTHER TO THE EAST.
CONDITIONS SHOULD REMAIN SUB VFR EVERYWHERE UNTIL 15Z WHEN VFR
CEILINGS AND VISIBILITIES SHOULD RETURN. ALTHOUGH CONDITIONS WILL BE
IMPROVING AND GENERALLY DRYING...THE MESO-LOW WILL LINGER OVERHEAD
KEEPING THE CHANCE FOR SHOWERS ALIVE THROUGH THE END OF THE TAF
PERIOD.
LONG TERM:
LOW STRATUS AND FOG ARE EXPECTED TO RETURN TUESDAY NIGHT INTO
WEDNESDAY. WEDNESDAY WILL BE THE DRIEST DAY BUT WILL STILL HAVE THE
CHANCE FOR DIURNAL SHOWERS AND STORMS. THURSDAY AND THURSDAY NIGHT
WILL FEATURE THE PASSAGE OF A COLD FRONT AND A RETURN TO SUB-VFR
CONDITIONS. VFR CONDITIONS WILL GRADUALLY RETURN TO THE AREA ON
FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...ELLIS/BADGETT
SHORT TERM...BADGETT
LONG TERM...SEC
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
937 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAKENING MID AND UPPER LEVEL TROUGH WILL SETTLE OVER CENTRAL
NORTH CAROLINA TODAY BRINGING MORE UNSETTLED CONDITIONS WITH LOCALLY
HEAVY RAIN. THE TROUGH WILL GRADUALLY MOVE TO NEAR THE COAST ON
TUESDAY REDUCING THE THREAT OF LOCALLY HEAVY RAIN.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 930 AM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
AN UPPER LEVEL MESO-LOW AND ASSOCIATED 500 MB TROUGH WILL LINGER
OVER THE SOUTHEASTERN COASTAL STATES TODAY...WHILE AT THE
SURFACE...RETURN FLOW AROUND A HIGH OF THE MID-ATLANTIC COAST WILL
KEEP LIGHT GRADUAL UPSLOPE FLOW OVER CENTRAL NORTH CAROLINA. CURRENT
RUN OF THE NAM SHOWS GOOD MOISTURE TRANSPORT AND CONVERGENCE OVER
THE CENTRAL AND EASTERN PORTIONS OF THE STATE. CURRENT SPC
MESO-ANALYSIS SHOWS PW VALUES BETWEEN 1.6 AND 1.8 INCHES ACROSS THE
CWA. THIS PATTERN SHOULD HOLD FOR MUCH OF THE DAY AS CURRENT AXIS OF
PRECIPITATION OVER THE CENTRAL PORTION OF THE CWA GRADUALLY MOVES
EASTWARD INTO THE I-95 CORRIDOR. FURTHER TO THE WEST A SHORTWAVE
TROUGH IS EXPECTED TO SWING THROUGH THE WESTERN HALF OF THE STATE
PROVIDING A LITTLE MORE FORCING FOR AFTERNOON SHOWERS AND
THUNDERSTORMS. HRRR MODEL INDICATES THAT SOME HEAVIER SHOWERS WILL
DEVELOP AND MOVE INTO SOUTHWESTERN COUNTIES THIS AFTERNOON. MUCH OF
THE CENTRAL PORTION OF THE CWA HAS RECEIVED SIGNIFICANT RAINFALL
OVER THE PAST 24 HOURS BUT RAINFALL RATES HAVE BEEN LOW ENOUGH THAT
ANY FLOODING PROBLEMS HAVE BEEN NON-EXISTENT AT THIS TIME. WE WILL
CONTINUE TO MONITOR URBAN AREAS AND SMALL STREAMS FOR FLOODING
ACTIVITY WITH CONTINUED RAINFALL THIS AFTERNOON.
AT THIS HOUR MUCH OF THE AREA IS OVERCAST...BUT SOME BREAKS IN THE
CLOUDS COULD PROVIDE SOME DIFFERENTIAL HEATING BOUNDARIES THIS
AFTERNOON. WHILE SHOWERS AND THE OCCASIONAL THUNDERSTORM WILL BE
PROBABLE THIS AFTERNOON...THE LIKELIHOOD THAT ANY OF THESE STORMS
BECOMES SEVERE IS RELATIVELY LOW. WHILE THERE IS SOME
INSTABILITY...EFFECTIVE SHEAR IS VIRTUALLY NON-EXISTENT AND LAPSE
RATES ARE MODEST AT BEST. NO DCAPE TO WORK WITH MAKES SEVERE WINDS
VERY UNLIKELY. EXPECT LOWER CEILINGS TO CONTINUE TO PREVAIL THROUGH
THE MORNING AND INTO THE AFTERNOON ALSO HINDERING INSTABILITY.
DESPITE THIS...HIGHS SHOULD STILL REACH NEAR THE 80 DEGREE MARK THIS
AFTERNOON AS SOUTHWESTERLY FLOW AND WARM AIR ADVECTION HELP ELEVATE
HIGHS TODAY. -ELLIS
SHOWERS AND SCATTERED THUNDERSTORMS SHOULD DIMINISH WITH LOSS OF
HEATING THIS EVENING. WITH THE BASE OF THE TROUGH STILL OVER THE
REGION... WE WILL CONTINUE TO CARRY LOW END POPS AND QPF UNDER 0.25.
LOWS 65-70. STRATUS AND FOG WILL AGAIN BE PROBLEMATIC ESPECIALLY
09Z-13Z/TUE. -BADGETT
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 250 AM MONDAY...
A CONTINUED WEAKENING TREND WITH THE TROUGH AND A GRADUAL SHIFT
EASTWARD WILL MEAN MORE SCATTERED AND LESS CONCENTRATED CONVECTIVE
RAINFALL ON TUESDAY AFTERNOON AND EVENING. SEVERAL MODEL SOLUTIONS
INDICATE THE SUBTROPICAL RIDGE EXTENDING WESTWARD FROM THE WESTERN
ATLANTIC OVER PORTIONS OF NC. AFTER A START TO THE DAY WITH LOW
STRATUS AND AREAS OF FOG... PARTLY SUNNY SKIES ARE EXPECTED. HIGHS
SHOULD REBOUND INTO THE LOWER TO MID 80S. HOWEVER... DEW POINTS WILL
STILL BE IN THE MID TO UPPER 60S. THE COOLER MET/NAM GUIDANCE LOOKS
MORE IN LINE WITH THE CURRENT EXPECTATIONS WITH THE SSW FLOW AND
PLENTY OF LOW LEVEL MOISTURE AND BROKEN AFTERNOON CLOUDINESS. WIDELY
SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. THIS
ACTIVITY WILL DIMINISH TUESDAY EVENING WITH LOSS OF HEATING. PARTLY
CLOUDY SKIES WITH AREAS OF FOG AGAIN EXPECTED LATE AT NIGHT. LOWS IN
THE MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...
UPPER LEVEL RIDGE BUILDS BRIEFLY OVER THE AREA ON WEDNESDAY... WHICH
SHOULD DIMINISH THE COVERAGE OF CONVECTION... ALTHOUGH DIURNALLY
DRIVEN THUNDERSTORMS CONTINUE TO BE POSSIBLE WITH THE MOIST AIRMASS
OVER THE AREA. PWATS WILL REMAIN NEAR 1.5... 2 STANDARD DEVIATIONS
ABOVE NORMAL FOR THIS TIME OF YEAR. WITH WEAK SHEAR... EXPECTING
PULSE TYPE STORMS. HIGHS IN THE MID 80S... LOWS MID 60S.
UPPER LEVEL RIDGE SHIFTS OFFSHORE THURSDAY. AFTERNOON THUNDERSTORMS
CONTINUE TO BE POSSIBLE IN THE AFTERNOON THURSDAY AS PWATS REMAIN
ABOVE NORMAL. BULK SHEAR INCREASES TO 25 TO 30 KTS... WHICH MAY
SUPPORT SOME MULTICELL ORGANIZATION. THICKNESSES REMAIN NEAR TO
SLIGHTLY ABOVE AVERAGE THURSDAY AND FRIDAY... FAVORING TEMPERATURES
CONTINUING TO A BE A FEW DEGREES ABOVE NORMAL... WITH HIGHS IN THE
80S AND LOWS IN THE UPPER 60S. THE TROUGH OVER THE MIDWEST MOVES
EASTWARD ON THURSDAY... AND THE ATTENDANT COLD FRONT PUSHES ACROSS
THE REGION FRIDAY. TIMING HAS TRENDED FASTER DURING TODAYS MODEL
RUNS... WITH THE FRONT MAKING IT THROUGH THE AREA EARLY FRIDAY...
AND TO THE CAROLINA COAST FRIDAY MORNING. STRONGEST DYNAMIC FORCING
REMAINS NORTH OVER NEW ENGLAND... AND WITH THE TIMING NOW LOOKING
MORE DIURNALLY UNFAVORABLE... DO NOT EXPECT A THREAT OF SEVERE
WEATHER.
&&
.AVIATION /12Z MONDAY THROUGH THURSDAY/...
AS OF 736 AM MONDAY...
MOSTLY MVFR CEILINGS WILL PREVAIL FOR THE NEXT SEVERAL HOURS WITH
SOME HEAVIER SHOWERS EXPECTED...ESPECIALLY AT CENTRAL AND EASTERN
TERMINALS WITH SOME IFR/LIFR CEILINGS POSSIBLE IN HEAVIER SHOWERS.
HEAVY SHOWERS AND THE OCCASIONAL THUNDERSTORM WILL MOVE THROUGH
KRDU...KFAY AND IN A COUPLE OF HOURS...KRWI. FOR NOW TRIAD SITES
KINT AND KGSO SHOULD REMAIN DRY FOR THE NEXT SEVERAL HOURS ALTHOUGH
SOME SHOWERS AND THUNDERSTORMS ARE POSSIBLE AS THE NEXT SHORTWAVE
PULSE MOVES THROUGH THE WESTERN PART OF THE STATE. AS THE AFTERNOON
PROGRESSES...CONDITIONS SHOULD BEGIN TO IMPROVE AS FAR AS CEILINGS
TO AS LOWER LEVELS OF THE ATMOSPHERE GRADUALLY DRY OUT. STILL PLENTY
OF MOISTURE TO MAINTAIN SHOWERS AND THUNDERSTORMS WELL INTO THE
AFTERNOON AND EVENING HOURS. WINDS TODAY SHOULD REMAIN LIGHT AND
FROM A SOUTHWESTERLY OR SOUTH SOUTHWESTERLY DIRECTION -ELLIS
IFR TO LIFR CIGS AND VSBYS SHOULD DEVELOP TONIGHT AND PERSIST INTO
EARLY TUESDAY (13Z-15Z)... THE SCATTERED OUT TO VFR. A FEW SHOWERS
AND THUNDERSTORMS MAY DEVELOP TUESDAY AFTERNOON.
LOW STRATUS AND FOG WILL AGAIN BE PROBLEMATIC TUESDAY NIGHT INTO
EARLY WED... THEN GENERALLY VFR CONDITIONS WED THROUGH THU.
HOWEVER... SCATTERED SHOWER AND THUNDERSTORM CHANCES WILL INCREASE
AGAIN LATE WED AFTERNOON AND ESPECIALLY THURSDAY AS ANOTHER TROUGH
APPROACHES FROM THE WEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...ELLIS/BADGETT
SHORT TERM...BADGETT
LONG TERM...SEC
AVIATION...ELLIS/BADGETT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
740 AM EDT MON MAY 20 2013
.SYNOPSIS...
WESTERN ATLANTIC HIGH PRESSURE WILL RIDGE ACROSS THE FORECAST AREA
FOR THE MAJORITY OF THIS WEEK. A DISTURBANCE ALOFT MOVING ACROSS THE
AREA EARLY IN THE WEEK...WILL MAINTAIN THE THREAT FOR SHOWERS AND
THUNDERSTORMS THROUGH TUESDAY. DRIER AND WARMER WEATHER EXPECTED
FOR MID WEEK BEFORE A COLD FRONT PUSHES ACROSS THE AREA
FRIDAY...BRINGING DRIER AND SLIGHTLY COOLER WEATHER FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...SLOW-MOVING SHOWERS AND T-STORMS WITH HEAVY
RAINFALL MAY HAVE LED TO FLOODING ACROSS PORTIONS OF DARLINGTON AND
MARLBORO COUNTIES WHERE FLOOD ADVISORIES AND WARNINGS HAVE BEEN
ISSUED THIS MORNING. FLASH FLOOD GUIDANCE FROM THE ATLANTA RFC WAS
EXCEEDED BY RADAR-ESTIMATED RAINFALL TOTALS ACROSS SEVERAL DRAINAGE
BASINS NEAR THE PEE DEE RIVER...MAINLY ALONG A LINE FROM MONT CLARE
NORTH-NORTHEAST TOWARD BENNETTSVILLE. NO REPORTS OF FLOODING HAVE
YET BEEN RECEIVED...ALTHOUGH RADAR-ESTIMATED STORM-TOTAL RAINFALL
OVER 5.5 INCHES IS INDICATED NEAR THE PEE DEE RIVER EAST OF
SOCIETY HILL.
THE LATEST SEVERAL HRRR RUNS (06-08Z) FOCUS ADDITIONAL HEAVY
RAINFALL THROUGH THE MORNING HOURS ACROSS LUMBERTON...MARION...
CONWAY...WHITEVILLE AND ELIZABETHTOWN...WHERE UPWARD OF 3 INCHES OF
RAIN IS DEPICTED IN THE MODEL ACROSS A LARGE AREA. FORTUNATELY THESE
LOCATIONS RECEIVED FAIRLY LIGHT RAINFALL AMOUNTS YESTERDAY WHICH
MEANS A GOOD PORTION OF ANY NEW RAINFALL SHOULD BE ABSORBED BY SOIL
RATHER THAN CONVERTING IMMEDIATELY TO RUNOFF. HIGH POPS (60-80
PERCENT) WILL BE MAINTAINED IN THE FORECAST THROUGH AFTERNOON.
AT THE COAST SHOWERS HAVE SO BEEN GENERALLY LIGHTER WITH NO FLOODING
CONCERNS. ALTHOUGH THE LATEST FEW HRRR RUNS SHOW AT LEAST SOME
POTENTIAL FOR HEAVY RAIN DURING THE MORNING HOURS AT THE COAST...
THE DEVELOPMENT OF A SEABREEZE SHOULD HELP CLEAR THE BULK OF THESE
SHOWERS OUT WITHIN 5-10 MILES OF THE BEACHES THIS AFTERNOON.
A WEAK UPPER LEVEL DISTURBANCE WILL ELONGATE NORTH-TO-SOUTH TODAY
ACROSS THE CENTRAL CAROLINAS...EVENTUALLY CLEAVING INTO TWO
INDIVIDUAL PIECES TONIGHT. CYCLONIC FLOW SURROUNDING THIS FEATURE
ALOFT IS VERY WEAK AND STORM CELL MOTION IS ANTICIPATED TO BE SLOW
TODAY. WITH PRECIPITABLE WATER VALUES NOW IN THE SUMMER/TROPICAL
RANGE OF 1.6 TO 1.8 INCHES AND MODEL FORECAST SOUNDINGS SHOWING
ALMOST 10000 FEET OF WARM CONVECTIVE CLOUD DEPTH (LCL AROUND 2500 FT
VERSUS AN ENVIRONMENTAL FREEZING LEVEL OF 12500 FT) THERE IS A
GROWING POTENTIAL FOR HEAVY RAINFALL...PERHAPS EVEN EXCESSIVE
RAINFALL AND FLOODING LATER TODAY. I DO NOT PLAN TO ISSUE A FLOOD
WATCH...BUT WILL INCLUDE HEAVY RAIN MENTION IN THE FORECAST GRIDS
AND HAZARDOUS WX OUTLOOK.
A STABILIZING BOUNDARY LAYER AND A WEAKENING UPPER LEVEL DISTURBANCE
TONIGHT SHOULD PRODUCE A RAPID DECREASE IN COVERAGE OF SHOWERS.
SOUTH WINDS MAY STILL ADVECT NOCTURNAL MARINE CONVECTION ONSHORE SO
THE HIGHEST POPS (30-40 PERCENT) WILL REMAIN OVERNIGHT NEAR THE
BEACHES...WITH LESSER CHANCES INLAND. LOWS SHOULD FALL TO 66-69 FOR
MOST AREAS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...HIGH PRESSURE OFFSHORE WILL CONTINUE ITS
INFLUENCE ACROSS THE CAROLINAS...BUT A DECREASING TREND IN
CONVECTION WITH WARMING TEMPS IS EXPECTED THROUGH THE SHORT TERM.
BUILDING 1000-500MB THICKNESSES AND SOME WEAK NVA BEHIND A DEPARTING
SHORTWAVE WILL CREATE SUBSIDENCE WITH INCREASED DRYING THROUGH THE
COLUMN. FORECAST PROFILES SUGGEST SIGNIFICANT DRY AIR ABOVE
800MB...AND THIS IS ECHOED IN PWATS FALLING TO 1.25 INCHES BY
WEDNESDAY. THIS WILL TEND TO INHIBIT MUCH IN THE WAY OF
CONVECTION...BUT WITH TEMPS RISING WELL INTO THE 80S...ISOLATED
CONVECTION WILL REMAIN POSSIBLE...ESPECIALLY TUESDAY. WILL CONTINUE
LOW-CHC POP TUESDAY AND SCHC WEDNESDAY...BUT WOULD NOT BE SURPRISED
IF WED ENDS UP BEING DRY ACROSS THE CWA.
TEMPS WILL RESPOND TO BULGING HEIGHTS...RISING FROM THE LOW/MID 80S
TUESDAY INTO THE MID/UPR 80S WEDNESDAY. LOWS WILL REMAIN WELL ABOVE
NORMAL FOR MID-MAY THANKS TO CONTINUED SOUTHERLY WINDS...FALLING
ONLY INTO THE UPPER 60S BOTH NIGHTS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...PATTERN CHANGE TO OCCUR DURING THE EXTENDED AS
COLD FRONT CROSSES THE AREA FRIDAY...USHERING IN A MUCH DRIER
AIRMASS TO THE CAROLINAS.
BERMUDA HIGH AND MID LEVEL RIDGING WILL PERSIST AT THE START OF THE
PERIOD...BUT FULL LATITUDE TROUGH WILL BEGIN TO DISPLACE THE RIDGE
CAUSING INCREASED CONVECTIVE CHANCES AND SLIGHTLY COOLER TEMPS. GFS
HAS SPED UP TIMING OF FRONT CONSIDERABLY...WHICH DOESN`T MAKE A LOT
OF SENSE BASED OFF RESTRICTIVE ANTECEDENT FLOW OF THE UPPER
PATTERN...AND FAVOR THE SLOWER CMC/ECMWF WHICH HAS THE FROPA
OCCURRING FRIDAY AFTN. THIS WILL SUPPORT ANOTHER DAY OF CONVECTION
AHEAD OF THE FRONT...BUT DRYING WILL OCCUR RAPIDLY BEHIND IT AS HIGH
PRESSURE BUILDS IN FROM THE NW. WHILE OVERALL TEMPERATURE CHANGE
WILL BE MINIMAL...WITH TEMPS ONLY A FEW DEGREES COOLER DURING THE
WKND...IT WILL BE MUCH DRIER...AND A BEAUTIFUL WKND APPEARS TO BE IN
STORE FOR THE AREA WITH TEMPS SLIGHTLY BELOW CLIMO.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...CURRENTLY VFR/MVFR ALONG THE COAST AND MVFR/IFR INLAND
WITH SOUTH WINDS 5-10 KTS. RADAR IMAGERY SHOWS A BAND OF SHRA
APPROACHING KLBT...AND HEAVIER PCPN COULD PRODUCE TEMPO IFR HERE
WITHIN THE NEXT HOUR OR TWO. -SHRA IS ONGOING NEAR THE COAST AS
WELL...BUT EXPECT VFR/MVFR TO PREVAIL.
MORE SHOWERS/TSTMS ARE POSSIBLE TODAY WITH PWAT VALUES > 1.5 INCHES
AND AN UPPER DISTURBANCE OVER THE CAROLINAS. WILL CARRY VCSH AT ALL
TERMS THROUGH THE AFTN HOURS...WITH BETTER PCPN CHANCES INLAND LATER
TODAY. EXPECT MAINLY VFR THROUGH THE DAY WITH MVFR/TEMPO IFR IN
HEAVIER SHOWERS. S-SW WINDS AOB 10 KTS THIS MORNING WILL INCREASE
TO 10-15 KTS THIS AFTN. RAIN CHANCES DIMINISH AFTER 00Z TUESDAY.
MODEL SOUNDINGS SUGGEST FOG COULD BE AN ISSUE TONIGHT AT KLBT/KFLO
WHERE PLENTY OF RAIN HAS ALREADY FALLEN.
EXTENDED OUTLOOK...SCATTERED SHOWERS/TSTMS WITH TEMPO MVFR/IFR ON
TUESDAY. CHANCE OF SHOWERS THURSDAY THROUGH EARLY FRIDAY. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
MARINE FORECAST THIS MORNING. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
THE OVERALL PATTERN WILL BE LITTLE CHANGED FROM YESTERDAY WITH
SURFACE HIGH PRESSURE REMAINING ANCHORED ALMOST 1000 MILES EAST OF
CAPE HATTERAS AND LOW PRESSURE MOVING SLOWLY ACROSS THE NORTHERN
PLAINS STATES. THIS WILL ENSURE A LIGHT TO MODERATE SOUTH WIND
ACROSS THE CAROLINA COASTAL WATERS TODAY AND TONIGHT.
SHOWERS AND EMBEDDED THUNDERSTORMS THIS MORNING SHOULD DECREASE IN
COVERAGE THIS AFTERNOON AS THE SEABREEZE CIRCULATION DEVELOPS...BUT
ANOTHER ROUND OF SCATTERED SHOWER ACTIVITY MAY DEVELOP TONIGHT. HIGH
MOISTURE CONTENT OF THE ATMOSPHERE MEANS HEAVY RAINFALL AND MARINE
VISIBILITY RESTRICTIONS ARE THE LARGEST THREATS.
SEAS CURRENTLY RANGE FROM 3-4 FT AT THE CAPE FEAR AREA BUOYS IN A
COMBINATION OF SOUTHEAST SWELL AND SOUTH WIND WAVES.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...RETURN FLOW AROUND BERMUDA HIGH PRESSURE
OFFSHORE CONTINUES THROUGH THE SHORT TERM...WITH SOUTHERLY WINDS OF
10-15 KTS COMMON EACH DAY. SEAS OF 2-3 FT TUESDAY WILL RISE TO 2-4
FT WEDNESDAY THANKS TO SLIGHTLY HIGHER WINDS. WHILE A DEAMPLIYFING
SE SWELL WILL BE PRESENT WITHIN THE WAVE SPECTRUM...SEAS WILL BE
PRIMARILY DERIVED FROM A SOUTHERLY 5-6 SEC WIND WAVE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...SOUTHERLY WINDS AROUND 15 KTS TO START THE
PERIOD WILL VEER THROUGH THURSDAY TO THE W/SW AS A COLD FRONT
APPROACHES FROM THE NW. THIS FRONT WILL CROSS THE WATERS DURING
FRIDAY...TURNING WINDS QUICKLY TO THE WEST FRIDAY EVE WITH DECREASED
SPEEDS BEFORE WINDS INCREASE FROM THE NORTH FRIDAY NIGHT. SEAS WILL
RISE TO 3-5 FT THURSDAY NIGHT AHEAD OF THE COLD FRONT BEFORE FALLING
BACK TO 2-4 FT LATE FRIDAY THANKS TO THE OFFSHORE COMPONENT OF THE
WIND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
641 AM EDT MON MAY 20 2013
.SYNOPSIS...
WESTERN ATLANTIC HIGH PRESSURE WILL RIDGE ACROSS THE FORECAST AREA
FOR THE MAJORITY OF THIS WEEK. A DISTURBANCE ALOFT MOVING ACROSS THE
AREA EARLY IN THE WEEK...WILL MAINTAIN THE THREAT FOR SHOWERS AND
THUNDERSTORMS THROUGH TUESDAY. DRIER AND WARMER WEATHER EXPECTED
FOR MID WEEK BEFORE A COLD FRONT PUSHES ACROSS THE AREA
FRIDAY...BRINGING DRIER AND SLIGHTLY COOLER WEATHER FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...SLOW-MOVING SHOWERS AND T-STORMS WITH HEAVY
RAINFALL MAY HAVE LED TO FLOODING ACROSS PORTIONS OF DARLINGTON AND
MARLBORO COUNTIES WHERE FLOOD ADVISORIES AND WARNINGS HAVE BEEN
ISSUED THIS MORNING. FLASH FLOOD GUIDANCE FROM THE ATLANTA RFC WAS
EXCEEDED BY RADAR-ESTIMATED RAINFALL TOTALS ACROSS SEVERAL DRAINAGE
BASINS NEAR THE PEE DEE RIVER...MAINLY ALONG A LINE FROM MONT CLARE
NORTH-NORTHEAST TOWARD BENNETTSVILLE. NO REPORTS OF FLOODING HAVE
YET BEEN RECEIVED...ALTHOUGH RADAR-ESTIMATED STORM-TOTAL RAINFALL
OVER 5.5 INCHES IS INDICATED NEAR THE PEE DEE RIVER EAST OF
SOCIETY HILL.
THE LATEST SEVERAL HRRR RUNS (06-08Z) FOCUS ADDITIONAL HEAVY
RAINFALL THROUGH THE MORNING HOURS ACROSS LUMBERTON...MARION...
CONWAY...WHITEVILLE AND ELIZABETHTOWN...WHERE UPWARD OF 3 INCHES OF
RAIN IS DEPICTED IN THE MODEL ACROSS A LARGE AREA. FORTUNATELY THESE
LOCATIONS RECEIVED FAIRLY LIGHT RAINFALL AMOUNTS YESTERDAY WHICH
MEANS A GOOD PORTION OF ANY NEW RAINFALL SHOULD BE ABSORBED BY SOIL
RATHER THAN CONVERTING IMMEDIATELY TO RUNOFF. HIGH POPS (60-80
PERCENT) WILL BE MAINTAINED IN THE FORECAST THROUGH AFTERNOON.
AT THE COAST SHOWERS HAVE SO BEEN GENERALLY LIGHTER WITH NO FLOODING
CONCERNS. ALTHOUGH THE LATEST FEW HRRR RUNS SHOW AT LEAST SOME
POTENTIAL FOR HEAVY RAIN DURING THE MORNING HOURS AT THE COAST...
THE DEVELOPMENT OF A SEABREEZE SHOULD HELP CLEAR THE BULK OF THESE
SHOWERS OUT WITHIN 5-10 MILES OF THE BEACHES THIS AFTERNOON.
A WEAK UPPER LEVEL DISTURBANCE WILL ELONGATE NORTH-TO-SOUTH TODAY
ACROSS THE CENTRAL CAROLINAS...EVENTUALLY CLEAVING INTO TWO
INDIVIDUAL PIECES TONIGHT. CYCLONIC FLOW SURROUNDING THIS FEATURE
ALOFT IS VERY WEAK AND STORM CELL MOTION IS ANTICIPATED TO BE SLOW
TODAY. WITH PRECIPITABLE WATER VALUES NOW IN THE SUMMER/TROPICAL
RANGE OF 1.6 TO 1.8 INCHES AND MODEL FORECAST SOUNDINGS SHOWING
ALMOST 10000 FEET OF WARM CONVECTIVE CLOUD DEPTH (LCL AROUND 2500 FT
VERSUS AN ENVIRONMENTAL FREEZING LEVEL OF 12500 FT) THERE IS A
GROWING POTENTIAL FOR HEAVY RAINFALL...PERHAPS EVEN EXCESSIVE
RAINFALL AND FLOODING LATER TODAY. I DO NOT PLAN TO ISSUE A FLOOD
WATCH...BUT WILL INCLUDE HEAVY RAIN MENTION IN THE FORECAST GRIDS
AND HAZARDOUS WX OUTLOOK.
A STABILIZING BOUNDARY LAYER AND A WEAKENING UPPER LEVEL DISTURBANCE
TONIGHT SHOULD PRODUCE A RAPID DECREASE IN COVERAGE OF SHOWERS.
SOUTH WINDS MAY STILL ADVECT NOCTURNAL MARINE CONVECTION ONSHORE SO
THE HIGHEST POPS (30-40 PERCENT) WILL REMAIN OVERNIGHT NEAR THE
BEACHES...WITH LESSER CHANCES INLAND. LOWS SHOULD FALL TO 66-69 FOR
MOST AREAS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...HIGH PRESSURE OFFSHORE WILL CONTINUE ITS
INFLUENCE ACROSS THE CAROLINAS...BUT A DECREASING TREND IN
CONVECTION WITH WARMING TEMPS IS EXPECTED THROUGH THE SHORT TERM.
BUILDING 1000-500MB THICKNESSES AND SOME WEAK NVA BEHIND A DEPARTING
SHORTWAVE WILL CREATE SUBSIDENCE WITH INCREASED DRYING THROUGH THE
COLUMN. FORECAST PROFILES SUGGEST SIGNIFICANT DRY AIR ABOVE
800MB...AND THIS IS ECHOED IN PWATS FALLING TO 1.25 INCHES BY
WEDNESDAY. THIS WILL TEND TO INHIBIT MUCH IN THE WAY OF
CONVECTION...BUT WITH TEMPS RISING WELL INTO THE 80S...ISOLATED
CONVECTION WILL REMAIN POSSIBLE...ESPECIALLY TUESDAY. WILL CONTINUE
LOW-CHC POP TUESDAY AND SCHC WEDNESDAY...BUT WOULD NOT BE SURPRISED
IF WED ENDS UP BEING DRY ACROSS THE CWA.
TEMPS WILL RESPOND TO BULGING HEIGHTS...RISING FROM THE LOW/MID 80S
TUESDAY INTO THE MID/UPR 80S WEDNESDAY. LOWS WILL REMAIN WELL ABOVE
NORMAL FOR MID-MAY THANKS TO CONTINUED SOUTHERLY WINDS...FALLING
ONLY INTO THE UPPER 60S BOTH NIGHTS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...PATTERN CHANGE TO OCCUR DURING THE EXTENDED AS
COLD FRONT CROSSES THE AREA FRIDAY...USHERING IN A MUCH DRIER
AIRMASS TO THE CAROLINAS.
BERMUDA HIGH AND MID LEVEL RIDGING WILL PERSIST AT THE START OF THE
PERIOD...BUT FULL LATITUDE TROUGH WILL BEGIN TO DISPLACE THE RIDGE
CAUSING INCREASED CONVECTIVE CHANCES AND SLIGHTLY COOLER TEMPS. GFS
HAS SPED UP TIMING OF FRONT CONSIDERABLY...WHICH DOESN`T MAKE A LOT
OF SENSE BASED OFF RESTRICTIVE ANTECEDENT FLOW OF THE UPPER
PATTERN...AND FAVOR THE SLOWER CMC/ECMWF WHICH HAS THE FROPA
OCCURRING FRIDAY AFTN. THIS WILL SUPPORT ANOTHER DAY OF CONVECTION
AHEAD OF THE FRONT...BUT DRYING WILL OCCUR RAPIDLY BEHIND IT AS HIGH
PRESSURE BUILDS IN FROM THE NW. WHILE OVERALL TEMPERATURE CHANGE
WILL BE MINIMAL...WITH TEMPS ONLY A FEW DEGREES COOLER DURING THE
WKND...IT WILL BE MUCH DRIER...AND A BEAUTIFUL WKND APPEARS TO BE IN
STORE FOR THE AREA WITH TEMPS SLIGHTLY BELOW CLIMO.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...NIGHTTIME SHOWERS ARE INCREASING IN COVERAGE OVER THE
EASTERN CAROLINAS AHEAD OF A WEAK UPPER LEVEL DISTURBANCE OVER THE
WESTERN CAROLINAS. MOISTURE FROM THESE SHOWERS SHOULD CREATE IFR
STRATUS IN FLO/LBT AFTER 08Z. ALONG THE COAST WARMER TEMPERATURES
DUE TO ONSHORE FLOW OFF THE ATLANTIC SHOULD MAINTAIN MVFR CIGS...
ALTHOUGH IT IS NOT IMPOSSIBLE THAT ISOLATED IFR CONDITIONS COULD
DEVELOP NEAR HEAVIER SHOWER ACTIVITY. AFTER DAYBREAK...CIGS WILL
GRADUALLY LIFT TO MVFR/VFR. SOUTHWEST WINDS WILL PREVAIL AOB 10 KTS
WITH GUSTS UP TO 18 KTS ALONG THE COAST LATER IN THE DAY. INCREASED
CHANCES FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
THROUGHOUT THE DAY...SLOWLY TAPERING OFF INTO THE EVENING HOURS.
FOR CURRENT FCST HAVE KEPT IN VCSH GIVEN UNCERTAINTY OF
TIMING/OCCURRENCE OF ANY CONVECTIVE ACTIVITY.
EXTENDED OUTLOOK...AFTN SHOWERS/TSTMS POSSIBLE MONDAY AND
TUESDAY. OTHERWISE PREVAILING VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM MONDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
MARINE FORECAST THIS MORNING. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
THE OVERALL PATTERN WILL BE LITTLE CHANGED FROM YESTERDAY WITH
SURFACE HIGH PRESSURE REMAINING ANCHORED ALMOST 1000 MILES EAST OF
CAPE HATTERAS AND LOW PRESSURE MOVING SLOWLY ACROSS THE NORTHERN
PLAINS STATES. THIS WILL ENSURE A LIGHT TO MODERATE SOUTH WIND
ACROSS THE CAROLINA COASTAL WATERS TODAY AND TONIGHT.
SHOWERS AND EMBEDDED THUNDERSTORMS THIS MORNING SHOULD DECREASE IN
COVERAGE THIS AFTERNOON AS THE SEABREEZE CIRCULATION DEVELOPS...BUT
ANOTHER ROUND OF SCATTERED SHOWER ACTIVITY MAY DEVELOP TONIGHT. HIGH
MOISTURE CONTENT OF THE ATMOSPHERE MEANS HEAVY RAINFALL AND MARINE
VISIBILITY RESTRICTIONS ARE THE LARGEST THREATS.
SEAS CURRENTLY RANGE FROM 3-4 FT AT THE CAPE FEAR AREA BUOYS IN A
COMBINATION OF SOUTHEAST SWELL AND SOUTH WIND WAVES.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...RETURN FLOW AROUND BERMUDA HIGH PRESSURE
OFFSHORE CONTINUES THROUGH THE SHORT TERM...WITH SOUTHERLY WINDS OF
10-15 KTS COMMON EACH DAY. SEAS OF 2-3 FT TUESDAY WILL RISE TO 2-4
FT WEDNESDAY THANKS TO SLIGHTLY HIGHER WINDS. WHILE A DEAMPLIYFING
SE SWELL WILL BE PRESENT WITHIN THE WAVE SPECTRUM...SEAS WILL BE
PRIMARILY DERIVED FROM A SOUTHERLY 5-6 SEC WIND WAVE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...SOUTHERLY WINDS AROUND 15 KTS TO START THE
PERIOD WILL VEER THROUGH THURSDAY TO THE W/SW AS A COLD FRONT
APPROACHES FROM THE NW. THIS FRONT WILL CROSS THE WATERS DURING
FRIDAY...TURNING WINDS QUICKLY TO THE WEST FRIDAY EVE WITH DECREASED
SPEEDS BEFORE WINDS INCREASE FROM THE NORTH FRIDAY NIGHT. SEAS WILL
RISE TO 3-5 FT THURSDAY NIGHT AHEAD OF THE COLD FRONT BEFORE FALLING
BACK TO 2-4 FT LATE FRIDAY THANKS TO THE OFFSHORE COMPONENT OF THE
WIND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...TRA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
257 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAKENING MID AND UPPER LEVEL TROUGH WILL SETTLE OVER CENTRAL
NORTH CAROLINA TODAY BRINGING MORE UNSETTLED CONDITIONS WITH LOCALLY
HEAVY RAIN. THE TROUGH WILL GRADUALLY MOVE TO NEAR THE COAST ON TUESDAY
REDUCING THE THREAT OF LOCALLY HEAVY RAIN.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 230 AM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
THE SLOW MOVING... ALMOST STUCK MID/UPPER LEVEL TROUGH... LOCATED
OVER WESTERN NC/SC IS EXPECTED TO ONLY SLOWLY BUDGE EASTWARD TODAY
AND TONIGHT. THIS IS A BIT SLOWER THAN HAD BEEN ADVERTISED BY
PREVIOUS MODELS... AND PUTS MUCH OF CENTRAL NORTH CAROLINA IN THE
REGION OF A LOCALLY HEAVY RAIN THREAT TODAY INTO TONIGHT. THE LATEST
MODEL FORECASTS INCLUDING THE HI-RES HRRR GUIDANCE WERE DEPICTING
MUCH OF THE EASTERN PIEDMONT... SANDHILLS AND PORTIONS OF THE
COASTAL PLAIN IN A REGION OF SIGNIFICANT LIFT OUT AHEAD OF THE TROUGH
THROUGH TONIGHT. THE HI-RES HRRR HAD A DECENT HANDLE ON THE CURRENT
AREAS OF SHOWERS. WE WILL GENERALLY FOLLOW THE FORECAST OUTPUT OF
CONVECTION THROUGH THE NEXT 6 HOURS... OR UNTIL SURFACE HEATING
TAKES OVER. THE AREA OF SHOWERS OVER THE SOUTHERN PIEDMONT
AND SANDHILLS SHOULD MOVE SLOWLY NNE INTO THE FAYETTEVILLE AND
RALEIGH AREAS THROUGH DAYBREAK... THEN WEAKEN OUT OVER THE
CENTRAL/NORTHERN COASTAL PLAIN THEREAFTER.
CONVECTION SHOULD AGAIN BLOSSOM THIS AFTERNOON WITH DIFFERENTIAL
HEATING WITH BREAKS IN THE CLOUDS AIDED BY THE SLUG OF COLDER AIR
ALOFT INCREASING LOW LEVEL INSTABILITY. THE INCREASINGLY WEAK
STEERING FLOW SHOULD ALLOW FOR SLOWER MOVING CONVECTION THIS
AFTERNOON AND EVENING... THAN OBSERVED SUNDAY. IN ADDITION... THE
PROLONGED SE FLOW FROM OFF THE GULF STREAM AND WESTERN ATLANTIC WILL
INCREASE DEW POINTS TO NEAR 70 THIS AFTERNOON. THIS POOLING OF DEEP
MOISTURE WITH PRECIPITABLE WATER VALUE FORECASTS ON THE ORDER OF
1.75 INCHES OVER THE EASTERN PIEDMONT AND WESTERN COASTAL PLAIN
SUGGEST A HEAVY RAIN THREAT. THE LACK OF A SIGNIFICANT LOW LEVEL
BOUNDARY AT THE CURRENT TIME SUGGESTS FLOODING WOULD PROBABLY BE
MORE LOCALIZED. THE HAZARDOUS WEATHER OUTLOOK WILL CONTINUE TO
HIGHLIGHT MAINLY URBAN AND SMALL STREAM FLOODING POTENTIAL WITH THE
LOCALLY HEAVY RAIN. HIGHS TODAY SHOULD INCH A BIT HIGHER THAN SUNDAY
WITH A FEW MORE BREAKS IN THE CLOUDS IN THE MORNING. HIGHS GENERALLY
78 TO 83.
SHOWERS AND SCATTERED THUNDERSTORMS SHOULD DIMINISH WITH LOSS OF
HEATING THIS EVENING. WITH THE BASE OF THE TROUGH STILL OVER THE
REGION... WE WILL CONTINUE TO CARRY LOW END POPS AND QPF UNDER 0.25.
LOWS 65-70. STRATUS AND FOG WILL AGAIN BE PROBLEMATIC ESPECIALLY
09Z-13Z/TUE.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 250 AM MONDAY...
A CONTINUED WEAKENING TREND WITH THE TROUGH AND A GRADUAL SHIFT
EASTWARD WILL MEAN MORE SCATTERED AND LESS CONCENTRATED CONVECTIVE
RAINFALL ON TUESDAY AFTERNOON AND EVENING. SEVERAL MODEL SOLUTIONS
INDICATE THE SUBTROPICAL RIDGE EXTENDING WESTWARD FROM THE WESTERN
ATLANTIC OVER PORTIONS OF NC. AFTER A START TO THE DAY WITH LOW
STRATUS AND AREAS OF FOG... PARTLY SUNNY SKIES ARE EXPECTED. HIGHS
SHOULD REBOUND INTO THE LOWER TO MID 80S. HOWEVER... DEW POINTS WILL
STILL BE IN THE MID TO UPPER 60S. THE COOLER MET/NAM GUIDANCE LOOKS
MORE IN LINE WITH THE CURRENT EXPECTATIONS WITH THE SSW FLOW AND
PLENTY OF LOW LEVEL MOISTURE AND BROKEN AFTERNOON CLOUDINESS. WIDELY
SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. THIS
ACTIVITY WILL DIMINISH TUESDAY EVENING WITH LOSS OF HEATING. PARTLY
CLOUDY SKIES WITH AREAS OF FOG AGAIN EXPECTED LATE AT NIGHT. LOWS IN
THE MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...
UPPER LEVEL RIDGE BUILDS BRIEFLY OVER THE AREA ON WEDNESDAY... WHICH
SHOULD DIMINISH THE COVERAGE OF CONVECTION... ALTHOUGH DIURNALLY
DRIVEN THUNDERSTORMS CONTINUE TO BE POSSIBLE WITH THE MOIST AIRMASS
OVER THE AREA. PWATS WILL REMAIN NEAR 1.5... 2 STANDARD DEVIATIONS
ABOVE NORMAL FOR THIS TIME OF YEAR. WITH WEAK SHEAR... EXPECTING
PULSE TYPE STORMS. HIGHS IN THE MID 80S... LOWS MID 60S.
UPPER LEVEL RIDGE SHIFTS OFFSHORE THURSDAY. AFTERNOON THUNDERSTORMS
CONTINUE TO BE POSSIBLE IN THE AFTERNOON THURSDAY AS PWATS REMAIN
ABOVE NORMAL. BULK SHEAR INCREASES TO 25 TO 30 KTS... WHICH MAY
SUPPORT SOME MULTICELL ORGANIZATION. THICKNESSES REMAIN NEAR TO
SLIGHTLY ABOVE AVERAGE THURSDAY AND FRIDAY... FAVORING TEMPERATURES
CONTINUING TO A BE A FEW DEGREES ABOVE NORMAL... WITH HIGHS IN THE
80S AND LOWS IN THE UPPER 60S. THE TROUGH OVER THE MIDWEST MOVES
EASTWARD ON THURSDAY... AND THE ATTENDANT COLD FRONT PUSHES ACROSS
THE REGION FRIDAY. TIMING HAS TRENDED FASTER DURING TODAYS MODEL
RUNS... WITH THE FRONT MAKING IT THROUGH THE AREA EARLY FRIDAY...
AND TO THE CAROLINA COAST FRIDAY MORNING. STRONGEST DYNAMIC FORCING
REMAINS NORTH OVER NEW ENGLAND... AND WITH THE TIMING NOW LOOKING
MORE DIURNALLY UNFAVORABLE... DO NOT EXPECT A THREAT OF SEVERE
WEATHER.
&&
.AVIATION /06Z MONDAY THROUGH THURSDAY/...
AS OF 236 AM MONDAY...
LIFR TO IFR CIGS ALONG WITH MVFR VSBYS EXPECTED THROUGH 15Z/MON.
SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ESPECIALLY FROM KFAY TO
KRDU THROUGH 12Z/MON. IFR TO MVFR CIGS ARE EXPECTED THROUGH THE DAY
WITH NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS... ESPECIALLY EAST
OF KINT/KGSO.... WHERE THE SHOWERS SHOULD BE MORE SCATTERED.
IFR TO LIFR CIGS AND VSBYS SHOULD DEVELOP TONIGHT AND PERSIST INTO
EARLY TUESDAY (13Z-15Z)... THE SCATTERED OUT TO VFR. A FEW SHOWERS
AND THUNDERSTORMS MAY DEVELOP TUESDAY AFTERNOON.
LOW STRATUS AND FOG WILL AGAIN BE PROBLEMATIC TUESDAY NIGHT INTO
EARLY WED... THEN GENERALLY VFR CONDITIONS WED THROUGH THU.
HOWEVER... SCATTERED SHOWER AND THUNDERSTORM CHANCES WILL INCREASE
AGAIN LATE WED AFTERNOON AND ESPECIALLY THURSDAY AS ANOTHER TROUGH
APPROACHES FROM THE WEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...SEC
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAKENING MID AND UPPER LEVEL TROUGH WILL SETTLE OVER CENTRAL
NORTH CAROLINA TODAY BRINGING MORE UNSETTLED CONDITIONS WITH LOCALLY
HEAVY RAIN. THE TROUGH WILL GRADUALLY MOVE TO NEAR THE COAST ON TUESDAY
REDUCING THE THREAT OF LOCALLY HEAVY RAIN.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 230 AM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
THE SLOW MOVING... ALMOST STUCK MID/UPPER LEVEL TROUGH... LOCATED
OVER WESTERN NC/SC IS EXPECTED TO ONLY SLOWLY BUDGE EASTWARD TODAY
AND TONIGHT. THIS IS A BIT SLOWER THAN HAD BEEN ADVERTISED BY
PREVIOUS MODELS... AND PUTS MUCH OF CENTRAL NORTH CAROLINA IN THE
REGION OF A LOCALLY HEAVY RAIN THREAT TODAY INTO TONIGHT. THE LATEST
MODEL FORECASTS INCLUDING THE HI-RES HRRR GUIDANCE WERE DEPICTING
MUCH OF THE EASTERN PIEDMONT... SANDHILLS AND PORTIONS OF THE
COASTAL PLAIN IN A REGION OF SIGNIFICANT LIFT OUT AHEAD OF THE TROUGH
THROUGH TONIGHT. THE HI-RES HRRR HAD A DECENT HANDLE ON THE CURRENT
AREAS OF SHOWERS. WE WILL GENERALLY FOLLOW THE FORECAST OUTPUT OF
CONVECTION THROUGH THE NEXT 6 HOURS... OR UNTIL SURFACE HEATING
TAKES OVER. THE AREA OF SHOWERS OVER THE SOUTHERN PIEDMONT
AND SANDHILLS SHOULD MOVE SLOWLY NNE INTO THE FAYETTEVILLE AND
RALEIGH AREAS THROUGH DAYBREAK... THEN WEAKEN OUT OVER THE
CENTRAL/NORTHERN COASTAL PLAIN THEREAFTER.
CONVECTION SHOULD AGAIN BLOSSOM THIS AFTERNOON WITH DIFFERENTIAL
HEATING WITH BREAKS IN THE CLOUDS AIDED BY THE SLUG OF COLDER AIR
ALOFT INCREASING LOW LEVEL INSTABILITY. THE INCREASINGLY WEAK
STEERING FLOW SHOULD ALLOW FOR SLOWER MOVING CONVECTION THIS
AFTERNOON AND EVENING... THAN OBSERVED SUNDAY. IN ADDITION... THE
PROLONGED SE FLOW FROM OFF THE GULF STREAM AND WESTERN ATLANTIC WILL
INCREASE DEW POINTS TO NEAR 70 THIS AFTERNOON. THIS POOLING OF DEEP
MOISTURE WITH PRECIPITABLE WATER VALUE FORECASTS ON THE ORDER OF
1.75 INCHES OVER THE EASTERN PIEDMONT AND WESTERN COASTAL PLAIN
SUGGEST A HEAVY RAIN THREAT. THE LACK OF A SIGNIFICANT LOW LEVEL
BOUNDARY AT THE CURRENT TIME SUGGESTS FLOODING WOULD PROBABLY BE
MORE LOCALIZED. THE HAZARDOUS WEATHER OUTLOOK WILL CONTINUE TO
HIGHLIGHT MAINLY URBAN AND SMALL STREAM FLOODING POTENTIAL WITH THE
LOCALLY HEAVY RAIN. HIGHS TODAY SHOULD INCH A BIT HIGHER THAN SUNDAY
WITH A FEW MORE BREAKS IN THE CLOUDS IN THE MORNING. HIGHS GENERALLY
78 TO 83.
SHOWERS AND SCATTERED THUNDERSTORMS SHOULD DIMINISH WITH LOSS OF
HEATING THIS EVENING. WITH THE BASE OF THE TROUGH STILL OVER THE
REGION... WE WILL CONTINUE TO CARRY LOW END POPS AND QPF UNDER 0.25.
LOWS 65-70. STRATUS AND FOG WILL AGAIN BE PROBLEMATIC ESPECIALLY
09Z-13Z/TUE.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 250 AM MONDAY...
A CONTINUED WEAKENING TREND WITH THE TROUGH AND A GRADUAL SHIFT
EASTWARD WILL MEAN MORE SCATTERED AND LESS CONCENTRATED CONVECTIVE
RAINFALL ON TUESDAY AFTERNOON AND EVENING. SEVERAL MODEL SOLUTIONS
INDICATE THE SUBTROPICAL RIDGE EXTENDING WESTWARD FROM THE WESTERN
ATLANTIC OVER PORTIONS OF NC. AFTER A START TO THE DAY WITH LOW
STRATUS AND AREAS OF FOG... PARTLY SUNNY SKIES ARE EXPECTED. HIGHS
SHOULD REBOUND INTO THE LOWER TO MID 80S. HOWEVER... DEW POINTS WILL
STILL BE IN THE MID TO UPPER 60S. THE COOLER MET/NAM GUIDANCE LOOKS
MORE IN LINE WITH THE CURRENT EXPECTATIONS WITH THE SSW FLOW AND
PLENTY OF LOW LEVEL MOISTURE AND BROKEN AFTERNOON CLOUDINESS. WIDELY
SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. THIS
ACTIVITY WILL DIMINISH TUESDAY EVENING WITH LOSS OF HEATING. PARTLY
CLOUDY SKIES WITH AREAS OF FOG AGAIN EXPECTED LATE AT NIGHT. LOWS IN
THE MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 245 PM SUNDAY...
SHOWER AND THUNDERSTORM COVERAGE SHOULD BEGIN TO INCREASE ONCE AGAIN
BY THE END OF THE WEEK WITH THE APPROACH OF OUR NEXT MID/UPPER LEVEL
TROUGH AND ASSOCIATED COLD FRONT. THERE IS STILL SOME UNCERTAINTY
(MAINLY DUE TO RUN TO RUN INCONSISTENCIES) WITH THE TIMING OF THE
COLD FRONTAL PASSAGE...BUT OVERALL THE TREND HAS BEEN WITH A QUICKER
PASSAGE. IN FACT...THE MODELS ARE IN GENERAL AGREEMENT WITH BRINGING
THE FRONT THROUGH THE FORECAST AREA EARLY FRIDAY...ALMOST 12-18
HOURS EARLIER THAN WHAT MODELS INDICATED 24 HOURS AGO.
THEREFORE...WILL SHOW POPS HIGHEST POPS CONCENTRATED DURING THE
THURSDAY/EARLY FRIDAY TIME FRAME...THEN DECREASING FROM WEST TO EAST
THROUGHOUT THE DAY ON FRIDAY. AS OF NOW...IT NOW APPEARS THE WEEKEND
WILL BE DRY AS HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING FRONT.
WITH INCREASED PRECIP CHANCES/CLOUDS ON THURSDAY AND FRIDAY...TEMPS
WILL MOSTLY BE IN THE LOW/MID 80S...WITH SLIGHTLY COOLER TEMPS
EXPECTED FOR THE WEEKEND (GENERALLY IN THE 70S).
&&
.AVIATION /06Z MONDAY THROUGH THURSDAY/...
AS OF 236 AM MONDAY...
LIFR TO IFR CIGS ALONG WITH MVFR VSBYS EXPECTED THROUGH 15Z/MON.
SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ESPECIALLY FROM KFAY TO
KRDU THROUGH 12Z/MON. IFR TO MVFR CIGS ARE EXPECTED THROUGH THE DAY
WITH NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS... ESPECIALLY EAST
OF KINT/KGSO.... WHERE THE SHOWERS SHOULD BE MORE SCATTERED.
IFR TO LIFR CIGS AND VSBYS SHOULD DEVELOP TONIGHT AND PERSIST INTO
EARLY TUESDAY (13Z-15Z)... THE SCATTERED OUT TO VFR. A FEW SHOWERS
AND THUNDERSTORMS MAY DEVELOP TUESDAY AFTERNOON.
LOW STRATUS AND FOG WILL AGAIN BE PROBLEMATIC TUESDAY NIGHT INTO
EARLY WED... THEN GENERALLY VFR CONDITIONS WED THROUGH THU.
HOWEVER... SCATTERED SHOWER AND THUNDERSTORM CHANCES WILL INCREASE
AGAIN LATE WED AFTERNOON AND ESPECIALLY THURSDAY AS ANOTHER TROUGH
APPROACHES FROM THE WEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...KRR
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
236 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAKENING MID AND UPPER LEVEL TROUGH WILL SETTLE OVER CENTRAL
NORTH CAROLINA TODAY BRINGING MORE UNSETTLED CONDITIONS WITH LOCALLY
HEAVY RAIN. THE TROUGH WILL GRADUALLY MOVE TO NEAR THE COAST ON TUESDAY
REDUCING THE THREAT OF LOCALLY HEAVY RAIN.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 230 AM MONDAY...
...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...
THE SLOW MOVING... ALMOST STUCK MID/UPPER LEVEL TROUGH... LOCATED
OVER WESTERN NC/SC IS EXPECTED TO ONLY SLOWLY BUDGE EASTWARD TODAY
AND TONIGHT. THIS IS A BIT SLOWER THAN HAD BEEN ADVERTISED BY
PREVIOUS MODELS... AND PUTS MUCH OF CENTRAL NORTH CAROLINA IN THE
REGION OF A LOCALLY HEAVY RAIN THREAT TODAY INTO TONIGHT. THE LATEST
MODEL FORECASTS INCLUDING THE HI-RES HRRR GUIDANCE WERE DEPICTING
MUCH OF THE EASTERN PIEDMONT... SANDHILLS AND PORTIONS OF THE
COASTAL PLAIN IN A REGION OF SIGNIFICANT LIFT OUT AHEAD OF THE TROUGH
THROUGH TONIGHT. THE HI-RES HRRR HAD A DECENT HANDLE ON THE CURRENT
AREAS OF SHOWERS. WE WILL GENERALLY FOLLOW THE FORECAST OUTPUT OF
CONVECTION THROUGH THE NEXT 6 HOURS... OR UNTIL SURFACE HEATING
TAKES OVER. THE AREA OF SHOWERS OVER THE SOUTHERN PIEDMONT
AND SANDHILLS SHOULD MOVE SLOWLY NNE INTO THE FAYETTEVILLE AND
RALEIGH AREAS THROUGH DAYBREAK... THEN WEAKEN OUT OVER THE
CENTRAL/NORTHERN COASTAL PLAIN THEREAFTER.
CONVECTION SHOULD AGAIN BLOSSOM THIS AFTERNOON WITH DIFFERENTIAL
HEATING WITH BREAKS IN THE CLOUDS AIDED BY THE SLUG OF COLDER AIR
ALOFT INCREASING LOW LEVEL INSTABILITY. THE INCREASINGLY WEAK
STEERING FLOW SHOULD ALLOW FOR SLOWER MOVING CONVECTION THIS
AFTERNOON AND EVENING... THAN OBSERVED SUNDAY. IN ADDITION... THE
PROLONGED SE FLOW FROM OFF THE GULF STREAM AND WESTERN ATLANTIC WILL
INCREASE DEW POINTS TO NEAR 70 THIS AFTERNOON. THIS POOLING OF DEEP
MOISTURE WITH PRECIPITABLE WATER VALUE FORECASTS ON THE ORDER OF
1.75 INCHES OVER THE EASTERN PIEDMONT AND WESTERN COASTAL PLAIN
SUGGEST A HEAVY RAIN THREAT. THE LACK OF A SIGNIFICANT LOW LEVEL
BOUNDARY AT THE CURRENT TIME SUGGESTS FLOODING WOULD PROBABLY BE
MORE LOCALIZED. THE HAZARDOUS WEATHER OUTLOOK WILL CONTINUE TO
HIGHLIGHT MAINLY URBAN AND SMALL STREAM FLOODING POTENTIAL WITH THE
LOCALLY HEAVY RAIN. HIGHS TODAY SHOULD INCH A BIT HIGHER THAN SUNDAY
WITH A FEW MORE BREAKS IN THE CLOUDS IN THE MORNING. HIGHS GENERALLY
78 TO 83.
SHOWERS AND SCATTERED THUNDERSTORMS SHOULD DIMINISH WITH LOSS OF
HEATING THIS EVENING. WITH THE BASE OF THE TROUGH STILL OVER THE
REGION... WE WILL CONTINUE TO CARRY LOW END POPS AND QPF UNDER 0.25.
LOWS 65-70. STRATUS AND FOG WILL AGAIN BE PROBLEMATIC ESPECIALLY
09Z-13Z/TUE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM SUNDAY...
THE MID/UPPER LEVEL WAVE (CAUSING ALL OF THE RAIN TODAY AND MONDAY)
WILL STILL BE LINGERING ACROSS THE EASTERN PORTIONS OF THE FORECAST
AREA ON TUESDAY...BEFORE FINALLY SHIFTING OFFSHORE TUESDAY NIGHT.
THEREFORE...SHOWER AND THUNDERSTORM CHANCES WILL REMAIN ELEVATED...
ALTHOUGH COVERAGE SHOULD BE LESS THAN PREVIOUS DAYS. THE HIGHEST
POPS ARE EXPECTED ACROSS THE EAST...AS THE WESTERN PORTIONS OF THE
FORECAST AREA MAY HAVE CONVECTIVE ACTIVITY MORE SUPPRESSED DUE TO
INCREASING SUBSIDENCE OF THE BACKSIDE OF TROUGH AXIS. HIGHS SHOULD
BE IN THE MID/UPPER 80S...WITH OVERNIGHT LOWS GENERALLY IN THE MID
60S.
SOME WEAK SHORTWAVE RIDGING WILL START TO BUILD OVER THE AREA BY
WEDNESDAY...WHILE AT THE SURFACE...THE BERMUDA HIGH WILL START TO
RIDGE WESTWARD INTO THE CAROLINAS. ALL OF THIS WILL TRANSLATE TO AN
EVEN FURTHER DECREASE IN PRECIP COVERAGE ON WEDNESDAY. HOWEVER...
SUFFICIENT MOISTURE WILL STILL BE IN PLACE OVER THE REGION...WITH
PWAT VALUES HOVERING NEAR 1.5 INCHES OR SO. THEREFORE...AM STILL
EXPECTING TO SEE WIDELY SCATTERED TO SCATTERED DIURNALLY DRIVEN
CONVECTION. HIGHS ONCE AGAIN SHOULD BE IN THE MID/UPPER 80S...WITH
OVERNIGHT LOWS IN THE MID/UPPER 60S.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 PM SUNDAY...
SHOWER AND THUNDERSTORM COVERAGE SHOULD BEGIN TO INCREASE ONCE AGAIN
BY THE END OF THE WEEK WITH THE APPROACH OF OUR NEXT MID/UPPER LEVEL
TROUGH AND ASSOCIATED COLD FRONT. THERE IS STILL SOME UNCERTAINTY
(MAINLY DUE TO RUN TO RUN INCONSISTENCIES) WITH THE TIMING OF THE
COLD FRONTAL PASSAGE...BUT OVERALL THE TREND HAS BEEN WITH A QUICKER
PASSAGE. IN FACT...THE MODELS ARE IN GENERAL AGREEMENT WITH BRINGING
THE FRONT THROUGH THE FORECAST AREA EARLY FRIDAY...ALMOST 12-18
HOURS EARLIER THAN WHAT MODELS INDICATED 24 HOURS AGO.
THEREFORE...WILL SHOW POPS HIGHEST POPS CONCENTRATED DURING THE
THURSDAY/EARLY FRIDAY TIME FRAME...THEN DECREASING FROM WEST TO EAST
THROUGHOUT THE DAY ON FRIDAY. AS OF NOW...IT NOW APPEARS THE WEEKEND
WILL BE DRY AS HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING FRONT.
WITH INCREASED PRECIP CHANCES/CLOUDS ON THURSDAY AND FRIDAY...TEMPS
WILL MOSTLY BE IN THE LOW/MID 80S...WITH SLIGHTLY COOLER TEMPS
EXPECTED FOR THE WEEKEND (GENERALLY IN THE 70S).
&&
.AVIATION /06Z MONDAY THROUGH THURSDAY/...
AS OF 236 AM MONDAY...
LIFR TO IFR CIGS ALONG WITH MVFR VSBYS EXPECTED THROUGH 15Z/MON.
SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ESPECIALLY FROM KFAY TO
KRDU THROUGH 12Z/MON. IFR TO MVFR CIGS ARE EXPECTED THROUGH THE DAY
WITH NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS... ESPECIALLY EAST
OF KINT/KGSO.... WHERE THE SHOWERS SHOULD BE MORE SCATTERED.
IFR TO LIFR CIGS AND VSBYS SHOULD DEVELOP TONIGHT AND PERSIST INTO
EARLY TUESDAY (13Z-15Z)... THE SCATTERED OUT TO VFR. A FEW SHOWERS
AND THUNDERSTORMS MAY DEVELOP TUESDAY AFTERNOON.
LOW STRATUS AND FOG WILL AGAIN BE PROBLEMATIC TUESDAY NIGHT INTO
EARLY WED... THEN GENERALLY VFR CONDITIONS WED THROUGH THU.
HOWEVER... SCATTERED SHOWER AND THUNDERSTORM CHANCES WILL INCREASE
AGAIN LATE WED AFTERNOON AND ESPECIALLY THURSDAY AS ANOTHER TROUGH
APPROACHES FROM THE WEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
907 PM CDT TUE MAY 21 2013
.UPDATE...
ISSUED AT 853 PM CDT TUE MAY 21 2013
ISENTROPIC LIFT PERSISTS ACROSS THE SOUTH AND WEST...WITH THE WEST
LIKELY GETTING SOME UPSLOPE COMPONENT AS WELL AS EASTERLY LOW
LEVEL WINDS CONTINUE TO PULL LOW LEVEL MOISTURE INTO THE REGION.
UPPED THE CHANCE OF RAIN SHOWERS TO LIKELY ACROSS PORTIONS OF THE
SOUTH FOR THE EVENING AND EARLY MORNING. SO FAR DO NOT SEE A FIRM
TREND ON CLEARING ACROSS THE NORTH YET. SO HAVE SLOWED THE
PROGRESSION OF CLEARING UNTIL LATER TONIGHT. THIS MAY CAUSE SOME
PROBLEMS WITH FOG FORMATION NORTH UNTIL LATE. UPSLOPE FLOW
CONTRIBUTING TO LIGHT FOG SOUTHWEST THIS EVENING.
UPDATE ISSUED AT 650 PM CDT TUE MAY 21 2013
AT 6 PM CDT...THE CLOUD SHIELD EXTENDS ACROSS ALL OF NORTH DAKOTA
EXCEPT THE FAR NORTHERN TIER OF COUNTIES WHERE BREAKS IN THE
OVERCAST ARE NOW FORMING. AFTER SUNSET THE EAST NORTHEAST FLOW OUT
OF CANADA WITH WARMER TEMPERATURES AND LOWER DEW POINTS WILL
FURTHER ERODE THE CLOUDS. WITH MINOT STILL REPORTED A LIGHT SHOWER
ADDED SPRINKLES FOR SEVERAL HOURS THIS EVENING ALONG AND NORTH OF
LAKE SAKAKAWEA EXCLUDING THE NORTHERN BORDER COUNTIES WHERE
CLEARING WILL DEFINITELY BE FOUND. ACROSS THE SOUTH HALF WILL
STILL SEE SCATTERED SHOWERS THIS EVENING FOLLOWED BY CLEARING
OVERNIGHT. WILL THE NORTH CLEARING BY MIDNIGHT...AND ABUNDANT
SURFACE MOISTURE PRESENT...AREAS OF FOG STILL LOOK REASONABLE.
TEMPERATURE TRENDS LOOK GOOD AND DID NOT TOUCH THEM WITH THIS
FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE END OF THE LONG DURATION
RAINFALL EVENT ACROSS THE AREA.
FOR TONIGHT...THE RAP THROUGHOUT THE DAY HAS HAD A GOOD HANDLE ON
THE STRATUS DECK ACROSS THE AREA..AND FOLLOWED ITS LATEST 19 UTC
RUN FOR CLOUD COVER THROUGH THE NIGHT WHICH ADVECTS DRIER AIR
SOUTHWEST AND SCOURS OUT THE STRATUS. DID ADD A MENTION OF FOG TO
THE NORTHWEST AND NORTH CENTRAL WHERE SKIES FIRST CLEAR TONIGHT
AND WINDS BECOME LIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING
INTO THE UPPER 30S AND SATURATION IN LIGHT OF THE RECENT RAINFALL.
A QUIET WEDNESDAY IS FORECAST WITH A SURFACE RIDGE AXIS ACROSS THE
AREA. GIVEN GOOD MODEL AGREEMENT...USED A BLEND OF THE 12 UTC
GEM/GFS/NAM/ECMWF AND 15 UTC SREF FOR ALL FIELDS...WITH GENERALLY
SUNNY SKIES AND HIGHS IN THE 60S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013
BY WEDNESDAY NIGHT AN UPPER LEVEL SHORTWAVE RIDGE BETWEEN THE
EXITING LOW PRESSURE SYSTEM TO THE EAST...AND THE ESTABLISHED UPPER
LEVEL LOW OVER THE WEST COAST/ROCKIES...WILL BE SITUATED OVER THE
PLAINS OF NORTH AMERICA. AT THE SURFACE...COOL HIGH PRESSURE RIDGE
MOVING SOUTH FROM CANADA NOSES INTO THE DAKOTAS.
BY THURSDAY THE SURFACE PRESSURE GRADIENT INCREASES AS THE
INTENSIFYING SURFACE LOW OVER THE ROCKIES/LEE OF THE ROCKIES SETS UP
A STRONGER SOUTHERLY/SOUTHEASTERLY WIND FLOW ACROSS THE WESTERN
PLAINS. SOUTHEAST WINDS 20 TO 30 MPH CAN BE EXPECTED OVER THE
WESTERN THIRD OF NORTH DAKOTA.
FRIDAY THROUGH THE MEMORIAL DAY WEEKEND...THE LARGE UPPER LEVEL LOW
OVER THE ROCKIES SETS UP A SOUTHWEST FLOW ALOFT OVER NORTH
DAKOTA...AND A SERIES OF UPPER LEVEL IMPULSES WILL TRAVERSE
NORTHEASTWARD ACROSS THE DAKOTAS. THUS A CHANCE OF THUNDERSTORMS
THROUGHOUT THIS PERIOD.
FAIRLY SEASONABLE TEMPERATURES IN THE LONG TERM...WITH HIGHS IN THE
60S AND 70S AND LOWS IN THE 40S AND 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 853 PM CDT TUE MAY 21 2013
CIRCULATION AROUND A LOW PRESSURE AREA IN MINNESOTA CAUSING LOW
LEVEL ISENTROPIC LIFT/UPSLOPE COMPONENTS MANIFESTING ITSELF AS
LOWER CEILINGS INTO THE LOW MVFR TO IFR CATEGORY FROM KJMS-KBIS-
KDIK...WITH KDIK LIKELY INTO THE LOW IFR THROUGH 10Z. AFTER 10Z
SHOULD SEE IMPROVING CONDITIONS TO MVFR THEN VFR AFTER 12Z.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT TUE MAY 21 2013
FLOOD WARNINGS CONTINUE FOR THE PIPESTEM CREEK NEAR PINGREE AND
THE FORECAST POINTS OF TOWNER...BANTRY AND WESTHOPE ON THE SOURIS.
CONTINUING TO MONITOR THE WINTERING RIVER NEAR KARLSRUHE AND THE
WILLOW CREEK NEAR WILLOW CITY WHICH MAY APPROACH FLOOD STAGE IN
THE NEXT 24-48 HOURS. HAVE HELD OFF ON A FLOOD WARNING FOR
NOW...AND WILL WATCH HOW THESE WATERWAYS RESPOND TO RUNOFF.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...JV
AVIATION...WAA
HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
703 PM CDT TUE MAY 21 2013
.UPDATE...
ISSUED AT 650 PM CDT TUE MAY 21 2013
AT 6 PM CDT...THE CLOUD SHIELD EXTENDS ACROSS ALL OF NORTH DAKOTA
EXCEPT THE FAR NORTHERN TIER OF COUNTIES WHERE BREAKS IN THE
OVERCAST ARE NOW FORMING. AFTER SUNSET THE EAST NORTHEAST FLOW OUT
OF CANADA WITH WARMER TEMPERATURES AND LOWER DEW POINTS WILL
FURTHER ERODE THE CLOUDS. WITH MINOT STILL REPORTED A LIGHT SHOWER
ADDED SPRINKLES FOR SEVERAL HOURS THIS EVENING ALONG AND NORTH OF
LAKE SAKAKAWEA EXCLUDING THE NORTHERN BORDER COUNTIES WHERE
CLEARING WILL DEFINITELY BE FOUND. ACROSS THE SOUTH HALF WILL
STILL SEE SCATTERED SHOWERS THIS EVENING FOLLOWED BY CLEARING
OVERNIGHT. WILL THE NORTH CLEARING BY MIDNIGHT...AND ABUNDANT
SURFACE MOISTURE PRESENT...AREAS OF FOG STILL LOOK REASONABLE.
TEMPERATURE TRENDS LOOK GOOD AND DID NOT TOUCH THEM WITH THIS
FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE END OF THE LONG DURATION
RAINFALL EVENT ACROSS THE AREA.
FOR TONIGHT...THE RAP THROUGHOUT THE DAY HAS HAD A GOOD HANDLE ON
THE STRATUS DECK ACROSS THE AREA..AND FOLLOWED ITS LATEST 19 UTC
RUN FOR CLOUD COVER THROUGH THE NIGHT WHICH ADVECTS DRIER AIR
SOUTHWEST AND SCOURS OUT THE STRATUS. DID ADD A MENTION OF FOG TO
THE NORTHWEST AND NORTH CENTRAL WHERE SKIES FIRST CLEAR TONIGHT
AND WINDS BECOME LIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING
INTO THE UPPER 30S AND SATURATION IN LIGHT OF THE RECENT RAINFALL.
A QUIET WEDNESDAY IS FORECAST WITH A SURFACE RIDGE AXIS ACROSS THE
AREA. GIVEN GOOD MODEL AGREEMENT...USED A BLEND OF THE 12 UTC
GEM/GFS/NAM/ECMWF AND 15 UTC SREF FOR ALL FIELDS...WITH GENERALLY
SUNNY SKIES AND HIGHS IN THE 60S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013
BY WEDNESDAY NIGHT AN UPPER LEVEL SHORTWAVE RIDGE BETWEEN THE
EXITING LOW PRESSURE SYSTEM TO THE EAST...AND THE ESTABLISHED UPPER
LEVEL LOW OVER THE WEST COAST/ROCKIES...WILL BE SITUATED OVER THE
PLAINS OF NORTH AMERICA. AT THE SURFACE...COOL HIGH PRESSURE RIDGE
MOVING SOUTH FROM CANADA NOSES INTO THE DAKOTAS.
BY THURSDAY THE SURFACE PRESSURE GRADIENT INCREASES AS THE
INTENSIFYING SURFACE LOW OVER THE ROCKIES/LEE OF THE ROCKIES SETS UP
A STRONGER SOUTHERLY/SOUTHEASTERLY WIND FLOW ACROSS THE WESTERN
PLAINS. SOUTHEAST WINDS 20 TO 30 MPH CAN BE EXPECTED OVER THE
WESTERN THIRD OF NORTH DAKOTA.
FRIDAY THROUGH THE MEMORIAL DAY WEEKEND...THE LARGE UPPER LEVEL LOW
OVER THE ROCKIES SETS UP A SOUTHWEST FLOW ALOFT OVER NORTH
DAKOTA...AND A SERIES OF UPPER LEVEL IMPULSES WILL TRAVERSE
NORTHEASTWARD ACROSS THE DAKOTAS. THUS A CHANCE OF THUNDERSTORMS
THROUGHOUT THIS PERIOD.
FAIRLY SEASONABLE TEMPERATURES IN THE LONG TERM...WITH HIGHS IN THE
60S AND 70S AND LOWS IN THE 40S AND 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 650 PM CDT TUE MAY 21 2013
AT 6 PM CDT...LOW PRESSURE CENTERED OVER SOUTHWEST MINNESOTA
CONTINUED TO PULL MOIST AIR INTO NORTH DAKOTA FROM THE EAST. MVFR
CONDITIONS WILL PREVAIL FROM KJMS-KBIS-KDIK...WITH A PERIOD OF IFR
POSSIBLE EARLY IN THE FORECAST TUESDAY EVENING AT KDIK. KISN-KMOT
WILL BE VFR THROUGH THE 00Z TAF PERIOD. AFTER MIDNIGHT...PATCHY
FOG WITH MVFR VSBYS POSSIBLE AT KMOT WHERE ABUNDANT RAINFALL
SHOULD CONTRIBUTE TO FOG FORMATION. VFR ALL TAF SITES AFTER 14Z.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT TUE MAY 21 2013
FLOOD WARNINGS CONTINUE FOR THE PIPESTEM CREEK NEAR PINGREE AND
THE FORECAST POINTS OF TOWNER...BANTRY AND WESTHOPE ON THE SOURIS.
CONTINUING TO MONITOR THE WINTERING RIVER NEAR KARLSRUHE AND THE
WILLOW CREEK NEAR WILLOW CITY WHICH MAY APPROACH FLOOD STAGE IN
THE NEXT 24-48 HOURS. HAVE HELD OFF ON A FLOOD WARNING FOR
NOW...AND WILL WATCH HOW THESE WATERWAYS RESPOND TO RUNOFF.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...JV
AVIATION...WAA
HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
539 PM CDT MON MAY 20 2013
.UPDATE...
ISSUED AT 540 PM CDT MON MAY 20 2013
UPDATE LATE THIS AFTERNOON DUE TO STRONG WINDS. WILL EXTEND THE
WIND ADVISORY FARTHER SOUTH TO INCLUDE AREAS ALONG AND NORTH OF
INTERSTATE 94.
VERY STRONG WINDS ACROSS FAR NORTH CENTRAL NORTH DAKOTA LATE THIS
AFTERNOON WITH WIND GUST TO 48KTS RECORDED AT ROLLA. CURRENT GUSTS
HAVE SUBSIDED BACK TO AROUND 40-42 KNOTS. WILL CONTINUE TO MONITOR
FOR POSSIBLE HIGH WIND WARNING THIS EVENING.
LATEST RAP ANALYSIS SHOWS AROUND 40-45 KNOTS OF WIND AT 925 MB
THROUGH MID EVENING...MAINLY ALONG AND EAST OF THE HIGHWAY 83
CORRIDOR AND ALONG AND NORTH OF INTERSTATE 94. ALSO 850 KNOT WINDS
INCREASE EARLY THIS EVENING ACROSS MUCH OF CENTRAL NORTH DAKOTA.
AFTER COORDINATION WITH FGF...WILL EXTEND THE CURRENT WIND
ADVISORY FARTHER SOUTH TO ALONG AND NORTH OF INTERSTATE 94...AND
KEEP AN EYE ON WINDS ACROSS THE FAR NORTH CENTRAL...HOLDING OFF ON
A HIGH WIND WARNING AT THIS TIME.
OTHERWISE NO SIGNIFICANT CHANGES TO THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 330 PM CDT MON MAY 20 2013
THE HIGHLIGHT OF THE SHORT TERM CONTINUES TO BE THE IMPACTS OF THE
ONGOING RAINFALL EVENT.
OVERALL THE GUIDANCE IS IN GOOD AGREEMENT...AND FOLLOWED A BLEND
OF THE 12 UTC GFS/GEM/ECMWF AND 15 UTC SREF FOR ALL FIELDS.
CURRENTLY THE STACKED LOW ACROSS FAR NORTHEAST SOUTH DAKOTA IS
EXPECTED TO SLOWLY PROPAGATE INTO CENTRAL MINNESOTA THROUGH
TUESDAY. WRAP AROUND RAINFALL IS EXPECTED TO SLOWLY DOWNTREND
THROUGH THE NIGHT AND INTO TUESDAY WITH AN ADDITIONAL ONE HALF TO
THREE QUARTERS OF AN INCH OF RAINFALL EXPECTED. SEE THE HYDROLOGY
DISCUSSION BELOW FOR DETAILS.
FOR THIS EVENING AND TONIGHT...DID MAINTAIN THE WIND ADVISORY FOR
THE WEST AND NORTH. THE WIND FIELD ACROSS THESE AREAS CONTINUES TO
STRENGTHEN WITH 40-45 KTS AT THE TOP OF A SHALLOW MIXED LAYER AS
DEPICTED BY THE 12 UTC NAM/GFS BUFR SOUNDINGS. THE STRONGEST WINDS
ARE EXPECTED ACROSS THE TURTLE MOUNTAINS WHERE GUSTS TO NEAR 50
MPH ARE POSSIBLE THROUGH EARLY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 PM CDT MON MAY 20 2013
THE MAIN FORECAST ISSUE THROUGH THE LONG TERM PERIOD WILL BE ONGOING
RIVER AND OVERLAND FLOODING CONCERNS. SEE HYDROLOGY DISCUSSION BELOW
FOR DETAILS. THEN ATTENTION TURNS TO THE UPCOMING WEEKEND AND THE
POSSIBILITY FOR SCATTERED THUNDERSTORMS AND POSSIBLE SEVERE WEATHER.
THERE IS FAIRLY GOOD MODEL AGREEMENT REGARDING THE POSITION AND
MOVEMENT OF THE CLOSED UPPER LEVEL LOW...ASSOCIATED WITH THE
PERSISTENT RAINS FOR THE PAST SEVERAL DAYS. THE UPPER LOW IS
FORECAST TO BE OVER THE SD/MN BORDER TUESDAY EVENING...THEN BECOME
MORE OF AN OPEN WAVE BY WEDNESDAY EVENING OVER IA/WI/IL AND THE
WESTERN GREAT LAKES. THIS SCENARIO WILL MEAN THE VERY HIGH/LIKELY
CHANCES OF RAIN TUESDAY NIGHT IN THE JAMES RIVER BASIN WILL LESSEN
TO SCATTERED IN NATURE BY WEDNESDAY. THE REST OF WESTERN AND CENTRAL
NORTH DAKOTA SHOULD SEE A DECREASE IN COVERAGE OF THE SHOWERS
TUESDAY NIGHT. SLIGHT CHANCES TO SCATTERED SHOWERS WEDNESDAY AS THE
SYSTEM MOVES EAST OF THE REGION.
BY WEDNESDAY EVENING AS THE UPPER LEVEL LOW/TROUGH MOVES EAST...A
WEAK UPPER LEVEL RIDGE WILL BUILD ACROSS THE NORTHERN PLAINS. THIS
WILL BE SHORT-LIVED AS ANOTHER LARGE UPPER LEVEL LOW/TROUGH SYSTEM
MOVES INTO THE PACIFIC NORTHWEST AND ROCKIES. THUS NO PRECIPITATION
MENTION FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.
FRIDAY THROUGH THE WEEKEND AND INTO MONDAY...THE UPPER LEVEL LOW
OVER THE ROCKIES IS FORECAST TO REMAIN IN PLACE...SETTING UP A
PROLONGED PERIOD OF SOUTHWESTERLY FLOW ALOFT FOR NORTH DAKOTA. THIS
WILL MEAN PERIODIC UPPER LEVEL SHORTWAVE ENERGY MOVING NORTHEASTWARD
THROUGH THE MEAN FLOW. AT THE SURFACE...THIS WILL RESULT IN BROAD
LOW PRESSURE ACROSS THE PLAINS...ALLOWING PLENTY OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. A PROLONGED LOW LEVEL JET AT H925-H850
WILL HELP TRANSPORT MOISTURE AND ENERGY NORTHWARD UP THE PLAINS.
THUS PERIODIC EPISODES OF SCATTERED THUNDERSTORMS WILL BE IN THE
FORECAST FRIDAY THROUGH THE MEMORIAL DAY WEEKEND.
WHILE TOO FAR OUT FOR MUCH CERTAINTY IN NARROWING DOWN SPECIFIC
AREAS OF CONCERN...SURFACE DEWPOINTS RISING INTO THE 50S BY FRIDAY
AND FORECAST CAPE DEVELOPING FROM THE SOUTHERN...CENTRAL...TO THE
NORTHERN PLAINS WOULD SUGGEST SOME SEVERE THUNDERSTORM ACTIVITY OVER
A BROAD AREA OF THE PLAINS FRIDAY AND SATURDAY. STAY TUNED FOR LATER
FORECASTS AND STORM PREDICTION CENTER OUTLOOKS FOR THE POTENTIAL FOR
SEVERE THUNDERSTORMS THIS COMING WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 540 PM CDT MON MAY 20 2013
LIGHT TO MODERATE RAINFALL WILL CONTINUE OVER ALL TERMINALS
THROUGH THE TAF PERIOD WITH MVFR/IFR CIGS/VSBYS. WIND GUSTS OF
30-40 KTS ARE POSSIBLE AT ALL TAF SITES LATE THIS AFTERNOON AND
THIS EVENING.
&&
.HYDROLOGY...
ISSUED AT 330 PM CDT MON MAY 20 2013
DID MAINTAIN THE FLOOD WATCH FOR ALL OF WESTERN AND CENTRAL NORTH
DAKOTA THROUGH TONIGHT. CALLS TO AREA EMERGENCY MANAGERS REVEAL THAT
FOR THE MOST PART...COUNTY AND TOWNSHIP ROAD IMPACTS ARE LIMITED.
HOWEVER...AS SOILS CONTINUE TO SATURATE...OVERLAND FLOOD CONCERNS
COULD INCREASE THROUGH THE NIGHT. FURTHERMORE...REPORTS HAVE BEEN
COMING IN OF WATER ENTERING BASEMENTS ACROSS THE AREA WITH THE
SATURATED GROUND. ADDITIONAL RIVER AND STREAM RISES ARE EXPECTED
OVER THE COMING DAYS. FOR THE MOST PART WITHIN BANK RISES ARE
ANTICIPATED. HOWEVER...THE SOURIS RIVER AT TOWNER IS EXPECTED TO
RISE ABOVE FLOOD STAGE AGAIN...THE PIPESTEM CREEK NEAR PINGREE IS
FORECAST TO RISE ABOVE MINOR FLOOD STAGE TOMORROW AFTERNOON WITH
THE WILLOW CREEK NEAR WILLOW CITY POSSIBLY APPROACHING FLOOD STAGE
BY WEDNESDAY EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH TUESDAY MORNING FOR NDZ001>005-009>013-
017>023-025-031>037-040>048-050-051.
WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR
NDZ001>005-009>013-017>023-025-031>037-040-041-043-044.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...TWH
HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
533 PM CDT MON MAY 20 2013
.UPDATE...
ISSUED AT 533 PM CDT MON MAY 20 2013
WATCHING WINDS ACROSS THE NW FA VERY CLOSELY THIS EVENING. THERE
IS AN AREA FROM ROLLA TO LANGDON WHERE THE AWOS SITES HAVE BEEN
FLIRTING WITH HIGH WIND WARNING CRITERIA (BOTH SUSTAINED AND
GUSTS). THE RAP INDICATES THE ADIABATIC LAYER WILL DEEPEN OVER
THE NEXT SEVERAL HOURS...AND 925MB WINDS WILL INCREASE. THE LAV
GUIDANCE APPEARS TO HAVE A DECENT HANDLE ON THE CURRENT
WINDS...AND INDICATES 40 MPH WITH GUSTS TO 60 MPH ACROSS THIS AREA
AT 00Z. CONFIDENCE IS NOT EXTREMELY HIGH THAT THIS WILL
OCCUR...BUT WILL MONITOR IT CLOSELY. THE RAP AND LAV GUIDANCE ALSO
INDICATE WIND ADVISORY CRITERIA WILL BE A BIT FURTHER SOUTH THAN
ANTICIPATED AS THE SURFACE LOW SLOWLY WARBLES SOUTHWARD...AND WILL
EXPAND THE WIND ADVISORY INTO THE COOPERSTOWN AND VALLEY CITY
AREA.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 339 AM CDT MON MAY 20 2013
VERY SEVERE FLOODING SITUATION OVER PARTS OF NORTHEASTERN NORTH
DAKOTA. KMVX 88D STORM PRECIP TOTALS EITHER VIA LEGACY STP OR THE
NEW DUAL POL ARE WOEFULLY UNDERDONE ESPECIALLY IN NORTHEASTERN
NORTH DAKOTA. SENT OUT A LONG LIST OF RAINFALL REPORTS SO FAR
WIDESPREAD 1-3 INCHES WITH POCKET OF 4-6 INCHES OR MORE FROM HOMME
DAM NEAR PARK RIVER ND UP THROUGH CRYSTAL TO MOUNTAIN ND TO
WALHALLA. LOTS OF CREEK FLOODING AND OVERLAND FLOODING THERE AND
UPDATED AREAL FLOOD WARNING FOR THIS AREA.
FOR TONIGHT EXPECT CONTINUED RAIN...THOUGH A BIT DRIER AIR ALOFT
SHOULD MEAN RAIN WILL BECOME MORE SCATTERED AND LIGHTER AS THE
NIGHT GOES ALONG. SOME THUNDER IN DRY SLOT FROM LITTLE FALLS TO ST
CLOUD AND SOME ISOLD THUNDER MAY MAKE IT INTO SOUTHEASTERN ZONES
THIS EVE. OTHERWISE JUST RAIN. ANOTHER HALF INCH OR A BIT MORE
THRU TONIGHT ISOLD 1 INCH MORE IN THE SOUTH TONIGHT. THE SOUTHERN
AREAS HAVE HAD THE LEAST AND CAN TAKE IT. WILL MAINTAIN AREAL
FLOOD WATCH AS ISSUED EARLIER.
FOR WINDS EXPANDED WIND ADV TO ROSEAU COUNTY AS ROX AWOS CONTINUES
TO SEE WIND GUSTS OVER 40 KTS AND SUSTAINED WINDS 25-30 KTS.
EXPECT TO SEE WINDY CONDITIONS THRU 03Z BEFORE THEY DIMINISH.
WATER VAPOR SHOWS UPR LOW AND SFC LOW STACKED SOUTH OF SISSETON
AND THIS LOW WILL BE STATIONARY AND BEGIN TO DRIFT SOUTH AND EAST
LATE TONIGHT INTO TUESDAY. WILL SEE LIGHTER RAINFALL ON
TUESDAY....BUT FOCUS MORE ON THE SOUTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 339 AM CDT MON MAY 20 2013
SYSTEM WILL DROP SOUTH ON WEDNESDAY WITH CLEARING AND DRYING
MOVING SOUTH. MAINLY DRY WED NIGH INTO THURSDAY WITH HIGH PRESSURE
COMING IN. FOR THU NIGHT INTO EARLY FRI MOST OF THE FA SHOULD
REMAIN DRY WITH THE 500MB RIDGE AXIS STILL OVER THE AREA. HOWEVER
THIS IS FAIRLY SHORT LIVED AS THE FLOW QUICKLY BEGINS TO BECOME
MORE SOUTHWEST. THIS SWITCH TO SOUTHWEST FLOW WILL BRING ACTIVE
WEATHER BACK INTO THE FA FOR BASICALLY THE REMAINDER OF THE LONG
TERM PERIOD. OPERATIONAL MODEL RUNS TODAY ARE SHOWING THE
POSSIBILITY OF NORTHEAST FLOW ERODING SOME OF THIS PCPN
POTENTIAL...ESPECIALLY IN THE NORTHEAST FA. THEREFORE THE BEST
CHANCES FOR PCPN SHOULD PROBABLY BE OVER THE WESTERN FA WITH
LESSER CHANCES TO THE EAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON MAY 20 2013
THE HIGHEST WIND SPEEDS SHOULD BE AT KDVL BUT KGFK/KTVF WILL STILL
SEE SOME PRETTY GUSTY EAST-NE WINDS. KBJI AND KFAR WILL BE QUITE A
BIT LOWER FOR WIND SPEEDS DUE TO THEIR CLOSER PROXIMITY TO THE SFC
LOW. EXACT VSBYS AND CEILINGS TOUGH TO CALL BUT IT DEFINITELY LOOKS
WET. WILL STICK WITH STEADY RAIN AT ALL TAF SITES EVEN THOUGH THERE
MAY BE SOME TEMPORARY BREAKS. CLOUD HEIGHTS SEEM TO BE INCREASING A
LITTLE THIS AFTERNOON BUT THEY SHOULD GO DOWN AGAIN TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 339 AM CDT MON MAY 20 2013
RIVER FLOOD WATCHES HAVE BEEN CANCELLED FOR THE RED RIVER AT
WAHPETON AND ITS SOUTHERN VALLEY MINNESOTA TRIBUTARIES.
RAINFALL AMOUNTS ARE EITHER INSUFFICIENT OR RUNOFF DUBIOUS TO
FORCE THESE POINTS TO FLOOD STAGE DURING THIS EVENT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FLOOD WATCH THROUGH TUESDAY EVENING FOR NDZ006>008-014>016-024-
026>030-038-039-049-052>054.
WIND ADVISORY UNTIL 1 AM CDT TUESDAY FOR NDZ006>008-014>016-024-
026-028-038-054.
MN...FLOOD WATCH THROUGH TUESDAY EVENING FOR MNZ001>009-013>017-
022>024-027>032-040.
WIND ADVISORY UNTIL 1 AM CDT TUESDAY FOR MNZ004-005-007.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/GODON
AVIATION...GODON
HYDROLOGY...WJB
BELOW. LITTLE IF ANY CHANGE FROM THE PREVIOUS FORECAST DISCUSSION
IN THIS UPDATE.
THE WIND ADVISORY AND FLOOD WATCH WILL CONTINUE AS PREVIOUSLY
FORECAST...WITH A CLOSE METWATCH ON EVENING CONVECTIVE TRENDS IN
THE SOUTHERN JAMES RIVER VALLEY. LOCAL RIVERS/STREAMS WILL ALSO BE
MONITORED THROUGH THE NIGHT FOR ADDITIONAL UPDATES.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 330 PM CDT SUN MAY 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONTINUED HEAVY RAINFALL
AND FLOODING THREAT ACROSS WESTERN AND CENTRAL NORTH DAKOTA
THROUGH MONDAY NIGHT AND A FLOOD WATCH REMAINS IN EFFECT.
OVERALL...THE DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT ON
RETROGRADING THE DEEP SURFACE LOW CURRENTLY ACROSS NORTHEAST SOUTH
DAKOTA WEST THROUGH TONIGHT...BEFORE PROPAGATING AGAIN EAST ON
MONDAY. GIVEN THE GOOD AGREEMENT...FOLLOWED A BLEND OF THE 12 UTC
GFS/GEM/ECMWF AND 15 UTC SREF FOR ALL FIELDS. THIS PLACES THE
LOW LEVEL DEFORMATION ZONE AND ASSOCIATED MODERATE TO HEAVY
RAINFALL GENERALLY ACROSS THE HIGHWAY 85 CORRIDOR AND INTO THE
NORTH CENTRAL THROUGH TONIGHT. WILL CONTINUE TO MONITOR THE JAMES
RIVER VALLEY LATE THIS AFTERNOON THROUGH EARLY EVENING AS BREAKS
IN THE CLOUD COVER IS ALLOWING SOME SURFACE BASED DESTABILIZATION
TO OCCUR. BEING SO CLOSE TO THE SURFACE LOW...DEEP LAYER SHEAR IS
MARGINAL FOR THIS PART OF THE CWA...HOWEVER...IT WOULD BE FAVORED
FOR A POSSIBLE WEAK SPIN- UP TORNADO/LAND SPOUT WITH THE LOW LEVEL
VORTICITY SHOULD SUFFICIENT NEAR SURFACE DESTABILIZATION OCCUR.
ALSO FOR TONIGHT...DID ISSUE WIND ADVISORY FOR WESTERN AND NORTH
CENTRAL NORTH DAKOTA FROM 00 UTC TO 15 UTC MONDAY. NAM/GFS BUFR
SOUNDINGS INDICATE 40-45 KTS TO MIX IN THE 900-875 MB LAYER AS THE
PRESSURE GRADIENT STRENGTHS WITH THE RETROGRADING SURFACE LOW.
FOR TOMORROW...AS ENERGY CURRENTLY ACROSS NEBRASKA PIVOTS AROUND
THE MAIN UPPER LEVEL LOW INTO NORTH DAKOTA...MODERATE TO HEAVY
RAIN WILL ONCE AGAIN BECOME WIDESPREAD ACROSS ALL OF WESTERN AND
CENTRAL NORTH DAKOTA. BY TUESDAY MORNING...AN ADDITIONAL TWO TO
THREE INCHES OF RAINFALL IS POSSIBLE FOR MUCH OF THE AREA. SEE THE
HYDROLOGY DISCUSSION BELOW FOR DETAILS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM CDT SUN MAY 19 2013
THE MAIN FORECAST ISSUE THROUGH THE LONG TERM PERIOD IS CONTINUED
HEAVY RAIN AND POTENTIAL FOR FLOODING. THE LATEST SUITE OF 19/12Z
MODELS IS IN VERY GOOD AGREEMENT REGARDING THE TRACK OF THE CLOSED
UPPER LOW THROUGH THE REGION. THE UPPER LOW MONDAY NIGHT IS FORECAST
TO BE OVER THE EASTERN DAKOTAS/WESTERN MINNESOTA BORDER...AND MOVE
SOUTHEASTWARD GRADUALLY TO SOUTHERN MINNESOTA BY DAYBREAK WEDNESDAY
MORNING...THEN MOVE EASTWARD INTO THE OHIO VALLEY AS ANOTHER UPPER
LEVEL LOW MAKES ITS WAY INTO THE WEST COAST. THIS CONSENSUS
INDICATES A PROLONGED PERIOD OF MODERATE TO HEAVY RAIN CONTINUING
MONDAY NIGHT INTO TUESDAY...IMPACTING MOST IF NOT ALL OF WESTERN AND
CENTRAL NORTH DAKOTA. SHOWERS ARE EXPECTED TO BECOME MORE SCATTERED
TUESDAY NIGHT INTO WEDNESDAY. RAINFALL AMOUNTS IN THE 24-HOUR PERIOD
FROM MONDAY NIGHT THROUGH TUESDAY NIGHT ARE EXPECTED TO RANGE FROM
AROUND 1/3 TO 2/3 OF AN INCH OVER A LARGE AREA OF WESTERN AND
CENTRAL NORTH DAKOTA. THIS IN ADDITION TO WHAT HAS ALREADY BEEN
RECEIVED THROUGH THIS WEEKEND...AND WHAT IS FORECAST FOR SUNDAY
NIGHT AND MONDAY...WILL KEEP FLOODING ISSUES THE MAIN THREAT ACROSS
THE REGION. IN ADDITION TO FLOODING CONCERNS ALONG SMALL
STREAMS...AND LOW LYING AREAS...WILL BE MONITORING RIVERS CLOSELY
THIS WEEK...ESPECIALLY THE FASTER RESPONDING POINTS SUCH AS APPLE
CREEK NEAR MENOKEN.
IN ADDITION TO THE RAINS...GUSTY WINDS ARE EXPECTED TO CONTINUE
MONDAY NIGHT THROUGH TUESDAY NIGHT...AS THE INTENSE UPPER LEVEL LOW
IS STACKED OVER THE SURFACE LOW...AND NORTHERLY WINDS FROM THE
SURFACE THROUGH H700 REMAIN UNIDIRECTIONAL FROM THE NORTH. EXPECTING
20 TO 30 MPH SUSTAINED WINDS WITH GUSTS TO NEAR 35 MPH AT TIMES.
UPPER LEVEL RIDGING WILL BECOME ESTABLISHED OVER THE REGION
BEGINNING WEDNESDAY AFTERNOON...AHEAD OF THE NEXT LARGE LOW PRESSURE
SYSTEM OVER THE WEST COAST/ROCKIES. THIS SYSTEM IS EXPECTED TO
REMAIN OVER THE ROCKIES AND BEGIN TO SET UP A SOUTHWESTERLY FLOW
ALOFT OVER THE NORTHERN PLAINS BY FRIDAY.
THE NEXT BEST CHANCE OF RAIN SHOWERS AND THUNDERSTORMS IS
FRIDAY...AND CONTINUING THROUGH THE WEEKEND.
EXPECT COOL WEATHER CONDITIONS TUESDAY WITH HIGHS IN THE
50S...WARMING GRADUALLY TO THE UPPER 60S AND 70S BY SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM CDT MON MAY 20 2013
MODERATE TO HEAVY RAINFALL WILL CONTINUE THROUGH THE TAF PERIOD
WITH MVFR/IFR CIGS/VSBYS. KISN/KDIK/KMOT AERODROMES WILL
EXPERIENCE THE CONDITIONS MENTIONED ABOVE THROUGH MONDAY.
KBIS/KJMS WILL SEE A RESPITE IN THE PRECIPITATION THIS SUNDAY
NIGHT WITH MORE RAIN DEVELOPING AFTER 06Z AT KJMS AND THEN SPREAD
WEST TO KBIS BY 10-12Z MONDAY. THEREAFTER...MODERATE TO HEAVY
RAINFALL WILL COMMENCE AT KBIS AND KJMS. A THUNDERSTORM THIS EARLY
MONDAY MORNING REMAINS POSSIBLE AS WELL FOR KJMS.
&&
.HYDROLOGY...
ISSUED AT 842 PM CDT SUN MAY 19 2013
TWO MAIN CONCERNS THIS EVENING...HAVE COORDINATED WITH THE
MISSOURI BASIN RIVER FORECAST CENTER/MBRFC THIS EVENING...AND WILL
DO THE FOLLOWING...
1) APPLE CREEK AT MENOKEN HAS NOT RESPONDED TO THE RAPID RISE
THAT WAS FORECAST TO OCCUR ALREADY. THIS HAS BEEN DELAYED UNTIL
LATER TONIGHT. WITH THE RIVER FORECAST TO REMAIN JUST A HARE BELOW
MINOR FLOOD STAGE...WILL ISSUE AN RVS THIS EVENING WITH LATER
SHIFTS RE-EVALUATING...ESPECIALLY WITH MONDAYS RAINFALL.
2) WILL ISSUE A FLOOD WARNING FOR THE LITTLE MUDDY CREEK NEAR
WILLISTON. BELIEVE WE CAN ADD SOME VALUE/LEAD TIME HERE WITH
PROJECTIONS MAINTAINING A STEADY RISE WELL INTO MINOR FLOOD STAGE
BY LATE MONDAY NIGHT AND TUESDAY. WITH ADDITIONAL RAINS COMING
MONDAY...HAVE A HIGH DEGREE OF CONFIDENCE THAT CURRENT RISING
TRENDS WILL CONTINUE.
3) A FEW MORE RIVER FORECAST POINTS ARE FORECAST TO REACH MINOR
FLOOD STAGE IN THE COMING DAYS...BUT ENOUGH TIME REMAINS TO
MONITOR RAINFALL AMOUNTS MONDAY AND TUESDAY. WILL HOLD OFF ON
ISSUING ANY OTHER PRODUCTS PER COORDINATION WITH MBRFC...AND WILL
BRIEF THE ONCOMING SHIFT OF THESE DECISIONS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH TUESDAY MORNING FOR NDZ001>005-009>013-
017>023-025-031>037-040>048-050-051.
WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR
NDZ001>005-009>013-017>019-021-031>033-040-041-043-044.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
HYDROLOGY...KS/AYD
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
359 PM EDT MON MAY 20 2013
.SYNOPSIS...
THE AIRMASS WILL BECOME INCREASINGLY MOIST AND UNSTABLE THROUGH MID
WEEK AS AN AREA OF LOW PRESSURE OVER THE UPPER MIDWEST SLOWLY
APPROACHES THE REGION. THIS LOW PRESSURE SYSTEM WILL TRACK THROUGH
THE EASTERN GREAT LAKES LATE WEDNESDAY AND PUSH A COLD FRONT SOUTH
ACROSS THE AREA. HIGH PRESSURE WILL RETURN FOR THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A HOT AND HUMID AIRMASS IS IN PLACE OVER THE REGION THIS AFTERNOON
AS WE REMAIN BENEATH THE UPPER LEVEL RIDGE. DEWPOINTS ARE IN THE MID
AND UPPER 60S ACROSS MOST OF THE AREA AND THE SPC RUC ANALYSIS
INDICATES OVER 2000 J/KG OF ML CAPE. DESPITE THIS...SPECIAL 18Z
SOUNDING OUT OF DTX INDICATES A STRONG CAP IS IN PLACE BETWEEN
875-650MB WHICH IS REPRESENTATIVE OF THE AIRMASS ACROSS NRN OHIO.
THE CU FIELD HAS ACTUALLY BEEN CLEARING ACROSS NW OHIO WHERE
DEWPOINTS HAVE MIXED DOWN INTO THE MID 60S. A LINE OF THUNDERSTORMS
IS DEVELOPING ACROSS WESTERN LOWER MICHIGAN AS A SPOKE OF ENERGY
EJECTS OUT OF THE UPPER TROUGH. HI-RES MODELS INDICATE THIS BAND
WILL CONTINUE TO FILL IN TO THE SOUTH ALONG THE ENHANCED CU FIELD TO
THE WEST AND CLIP THE TOLEDO AREA BEFORE MOVING EAST ACROSS LAKE
ERIE BETWEEN 00-03Z. IF THIS OCCURS...THERE IS THE POTENTIAL FOR
SOME THUNDERSTORMS TO BE SEVERE ALTHOUGH INSTABILITY WILL BE
DECREASING AND WIND FIELD IN NW OHIO IS NOT AS FAVORABLE. WILL CARRY
POPS ACROSS MAINLY THE NORTHERN CWA TONIGHT TO ACCOUNT FOR THIS
ACTIVITY WITH POPS INCREASING ACROSS WESTERN AREAS TOWARDS DAWN AS A
LOW LEVEL JET APPROACHES. TEMPERATURES WILL BE MILD OVERNIGHT WITH
LOWS ONLY DROPPING INTO THE UPPER 60S/NEAR 70 DEGREES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
UPPER LEVEL RIDGE AXIS WILL SHIFT EAST OF THE AREA ON TUESDAY AS THE
APPROACHING LOW PRESSURE SYSTEM MOVES INTO THE WESTERN LAKES REGION.
SHORTWAVE ENERGY IS EXPECTED TO EJECT OUT OF THE TROUGH TOWARDS THE
AREA AND HELP TO INITIATE CONVECTION. MODELS ALSO INDICATE A LOW
LEVEL JET WILL CLIP NW OHIO ON TUESDAY MORNING AND CONVECTION COULD
MOVE INTO THE AREA FROM THE WEST DURING THE MORNING. THERE IS SOME
UNCERTAINTY AS TO HOW ACTIVITY WILL EVOLVE...IF IT WILL CONTINUE
EASTWARD DOWN WIND OF THE LLJ OR IF WAIT UNTIL WE DESTABILIZE TO
INITIATE. CLOUD COVER COULD BE A LIMITING FACTOR FOR DESTABILIZATION
BUT EXPECT WE WILL STILL SEE STRONG WITH TEMPERATURES IN THE LOW 80S
AND DEWPOINTS IN THE 60S. A SPEED MAX AT 500MB WILL ALSO MOVE ACROSS
NW OHIO AND HELP TO SUPPORT CONVECTION. GIVEN THE FAVORABLE SHEAR
AND MODERATE INSTABILITY THE WESTERN HALF OF THE FORECAST AREA IS IN
A SLIGHT RISK FOR SEVERE WEATHER. EXPECTING THE PRIMARY THREAT TO BE
WIND GIVEN THE STRONG FLOW ALOFT. FREEZING LEVELS ARE HIGH NEAR
13.5KFT SO ONLY THE STRONGEST STORMS WILL BE ABLE TO PRODUCE HAIL
AND THE SURFACE FRONT REMAINS TO OUR WEST SO LOW LEVEL SHEAR WILL
NOT BE VERY FAVORABLE FOR TORNADOGENESIS. WITH THAT SAID...A LOW
CHANCE DOES STILL REMAIN FOR BOTH HAIL AND TORNADOES. SHEAR IS
CONSIDERABLY LOWER ACROSS THE EASTERN CWA AND STORM MOTION WILL BE
TO THE NORTHEAST AT ABOUT 35 MPH SO THE SEVERE THREAT WILL BE
LOWER...MAINLY EAST OF I-71.
EXPECTING A LULL IN SHOWERS AND THUNDERSTORMS ON TUESDAY NIGHT SO
WILL JUST HOLD ONTO A CHANCE POP. AN UPPER LEVEL JET WILL ROUND THE
BASE OF THE TROUGH TUESDAY NIGHT WITH THE TROUGH AXIS SWINGING
NORTHEAST TOWARDS THE OHIO VALLEY ON WEDNESDAY. CLOUD COVER IS AGAIN
IN QUESTION BUT LARGE SCALE ASCENT WILL BE STRONGER ON WEDNESDAY AND
EXPECT WIDESPREAD SHOWERS AND THUNDERSTORMS DURING THE DAY. THERE IS
AGAIN A SLIGHT RISK OF SEVERE STORMS ACROSS NEARLY THE ENTIRE
FORECAST AREA WITH BETTER INSTABILITY FOCUSED ACROSS THE EAST.
THE LOW PRESSURE SYSTEM WILL MOVE NORTHEAST THROUGH THE CENTRAL
GREAT LAKES ON WEDNESDAY AND FINALLY PUSH A COLD FRONT SOUTH ACROSS
THE AREA WEDNESDAY NIGHT AND THURSDAY. INSTABILITY AXIS WILL BE TO
OUR EAST FINALLY BY THURSDAY SO ONLY CARRIED THUNDERSTORMS IN THE
SOUTHERN COUNTIES WITH HIGHS NEAR TO JUST SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
BY THE START OF THE LONG TERM PERIOD...HIGH PRESSURE IS EXPECTED TO
BE SITUATED OVER THE CENTRAL GREAT LAKES. THIS WILL RESULT IN DRY
NORTHERLY FLOW FOR THE AREA FOR THE ENTIRE WEEKEND. THE ENTIRE FOUR
DAY LONG TERM PERIOD SHOULD BE DRY. TEMPS WILL STRUGGLE TO GET OUT
OF THE MIDDLE 60S ON FRIDAY AND OUT OF THE UPPER 60S BOTH SATURDAY
AND SUNDAY. READINGS SHOULD RETURN TO CLOSE TO NORMAL ON MONDAY AS
A WARM FRONT APPROACHES FROM THE SOUTH.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AREA OF STRATUS OVER N-CENTRAL HAS LIFTED TO MVFR AND CONTINUES
TO ERODE FROM THE EDGES. EXPECT ALL AREAS TO BE VFR IN AN HOUR OR
TWO. STILL A LOT OF QUESTIONS ABOUT THUNDERSTORM ACTIVITY DURING
THE PERIOD. BEST GUESS RIGHT NOW IS THAT NW OH COULD SEE SOME
STORMS TOWARD EVENING. WILL GO WITH A MENTION OVER ABOUT THE WEST
HALF OF THE AREA. EASTERN AREAS SHOULD BE CAPPED AND WILL REMAIN
DRY THROUGH 18Z TUESDAY. ANOTHER ROUND OF STORMS COULD AFFECT
WESTERN AREAS BY MIDDAY TUESDAY. S TO SW FLOW WILL CONTINUE.
SPEEDS SHOULD BE 5 KNOTS OR LESS LATER TONIGHT WHICH SHOULD ALLOW
SOME PATCHY MVFR FOG TO DEVELOP BEFORE DAYBREAK. SPEEDS WILL
INCREASE ON TUESDAY MORNING WITH GUSTS TO 20 KNOTS LIKELY. KERI
ALREADLY HAS A LAKE BREEZE. DO NOT THINK IT WILL REACH KCLE TODAY.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS OVERNIGHT THROUGH
THURSDAY.
&&
.MARINE...
SOUTH TO SOUTHWEST FLOW WILL CONTINUE ON THE LAKE TILL A COLD FRONT
CROSSES THE LAKE SOMETIME EARLY THURSDAY. SPEEDS SHOULD MAINLY BE
UNDER 15 KNOTS TILL THE FRONT ARRIVES. ONSHORE FLOW COULD DEVELOP ON
THE NEARSHORE WATERS BOTH TUESDAY AND WEDNESDAY. STRONG TO SEVERE
STORMS APPEAR POSSIBLE BOTH TUESDAY AND WEDNESDAY. BOATERS WILL
NEED TO REMAIN ALERT. SMALL CRAFT ADVISORIES APPEAR LIKELY FOR
THURSDAY AND FRIDAY WITH STRONG NORTHWEST FLOW BEHIND THE FRONT.
SOME SHOWERS ARE LIKELY ON THURSDAY. FRIDAY AND SATURDAY WILL BE
DRY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
309 PM EDT MON MAY 20 2013
.SYNOPSIS...
A WARM AND HUMID AIRMASS WILL REMAIN IN PLACE BEFORE A COLD FRONT
ARRIVES ON THURSDAY. MID LEVEL RIDGING WILL SLIDE EAST OF OUR AREA
TONIGHT AS LOW PRESSURE SLOWLY MOVES SOUTH AND EAST ACROSS THE
NORTHERN PLAINS. CHANCES FOR PRECIPITATION WILL INCREASE AS THIS
LOW APPROACHES OUR AREA OVER THE NEXT COUPLE OF DAYS.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID LEVEL RIDGE EXTENDING ACROSS THE SOUTHEASTERN CONUS AND INTO
OUR FORECAST AREA IS KEEPING CONVECTION OUT OF OUR AREA THIS
AFTERNOON DESPITE AN UNSTABLE AIRMASS. A CU DECK WILL THIN LATE
THIS AFTERNOON AND EVENING AS WE BEGIN TO LOSE THE PEAK HEATING OF
THE DAY. TONIGHT...MOST CONVECTIVE MODELS ARE INDICATING
DEVELOPMENT OF THUNDERSTORMS WELL WEST OF OUR AREA ASSOCIATED WITH
A DISTURBANCE ROUNDING THE BASE OF A TROUGH EXTENDING SOUTH OF LOW
PRESSURE ACROSS THE NORTHERN PLAINS. THIS CONVECTION IS EXPECTED
TO HEAD EAST TO NORTHEAST THROUGHOUT THE NIGHT AS PLENTY OF
ELEVATED INSTABILITY WILL BE IN PLACE. WHATEVER IS LEFT OF THIS
CONVECTION LATE TONIGHT MAY MAKE IT INTO OUR WESTERN ZONES AFTER
MIDNIGHT. WAS FAIRLY AGGRESSIVE IN THE FORECAST ON BRINGING
SHOWERS AND THUNDERSTORMS INTO THE WESTERN ZONES LATE TONIGHT
WHILE GRADUALLY WEAKENING THEM AS THEY SHIFT EASTWARD ACROSS OUR
AREA TUESDAY MORNING.
ANOTHER MILD NIGHT IS FORECAST FOR TONIGHT WITH OVERNIGHT LOWS
IN THE MID TO UPPER 60S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
OVERALL PATTERN FOR THE SHORT TERM TIME PERIOD IS FOR A LOW OVER
THE NORTHERN PLAINS TO SLOWLY SHEAR EASTWARD TUESDAY THROUGH
TUESDAY NIGHT...BEFORE GETTING ABSORBED INTO A DEEPENING TROUGH
ACROSS THE GREAT LAKES. AS THIS SYSTEM BEGINS TO GET SHEARED INTO
SOUTHWESTERLY FLOW ACROSS OUR REGION...TIMING OF INDIVIDUAL PIECES
OF ENERGY AND ASSOCIATED CONVECTION BECOMES UNCERTAIN.
BASED ON THE NEAR TERM FORECAST DECAYING CONVECTION ACROSS OUR
ZONES TUESDAY MORNING...THERE WOULD BE A PORTION OF THE DAY
TUESDAY WHERE THE BOUNDARY LAYER WILL BE WORKED OVER. THEREFORE
THERE MAY BE SEVERAL HOURS DURING THE FIRST PART OF THE DAY
TUESDAY WHERE LITTLE TO NO CONVECTION IS OCCURRING IN OUR FORECAST
AREA. THIS SOLUTION IS BEING INDICATED BY THE MAJORITY OF COMPUTER
MODELS. BY LATE TUESDAY AFTERNOON INSTABILITY WOULD HAVE INCREASED
AND SUFFICIENT RECOVERY OF THE BOUNDARY LAYER IS EXPECTED TO HAVE
OCCURRED. FORCING ASSOCIATED WITH ANY SHORTWAVE ENERGY EJECTING
EAST FROM THE LOW OVER THE PLAINS WILL HELP TO TRIGGER CONVECTIVE
DEVELOP LATE TUESDAY AFTERNOON. ALTHOUGH EXACT TIMING AND
PLACEMENT OF THE CONVECTION IS HIGHLY UNCERTAIN AT THIS TIME...UP
TO 45 KT OF 0-6 KM SHEAR MAY BE PRESENT ACROSS THE NORTHWESTERN
HALF OF OUR FORECAST AREA. THEREFORE...IF CONVECTION DOES GET GOING
TUESDAY AFTERNOON AND EVENING ACROSS OUR NORTHWEST...THERE WILL
BE THE POTENTIAL FOR SOME OF THESE STORMS TO BECOME SEVERE. THE
MAIN THREAT FROM THESE STORMS WOULD BE DAMAGING WIND AND ISOLATED
LARGE HAIL. THIS THREAT IS BEING HIGHLIGHTED IN THE HWO.
CHANCES FOR SHOWER AND THUNDERSTORMS WILL CONTINUE INTO TUESDAY
NIGHT AND INTO THE DAY ON WEDNESDAY AS THE LOW PROGRESSES NEARER
TO OUR AREA. SHEAR AND INSTABILITY WILL DECREASE ON TUESDAY NIGHT
AND WEDNESDAY....WHICH SHOULD LESSEN THE OVERALL SEVERE THREAT.
HOWEVER...ON WEDNESDAY THERE MAY STILL BE SUFFICIENT INSTABILITY
TO COMBINE WITH ABOUT 35 KT OF 0-6 KM SHEAR TO PRODUCE ISOLATED
CHANCES FOR DAMAGING WINDS AND LARGE HAIL SHOULD STORMS GET
ORGANIZED.
BY WEDNESDAY EVENING THE BEST CHANCES FOR PRECIPITATION WILL SHIFT
EAST OF OUR AREA ALONG WITH THE BEST FORCING.
TEMPERATURES WILL BE ON A DOWNWARD TREND THROUGHOUT THE SHORT TERM
TIME PERIOD. ON TUESDAY EXPECT UPPER 80S ACROSS THE EAST TO LOWER
80S ACROSS THE WEST. BY WEDNESDAY...CLOUD COVER AND PRECIPITATION
WILL KEEP TEMPERATURES LOWER THAN TUESDAY. OVERNIGHT LOWS WILL
CONTINUE TO BE MILD BOTH TUESDAY AND WEDNESDAY NIGHT AS WE REMAIN
IN THIS WARM AND HUMID AIRMASS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE UPPER LEVEL TROUGH WILL PIVOT EAST ACROSS OUR AREA THROUGH THE
DAY ON THURSDAY. THIS COMBINED WITH SOME LINGERING
INSTABILITIES...WILL KEEP THE THREAT OF SHOWERS AND A FEW
THUNDERSTORMS GOING THROUGH THE AFTERNOON. AS THE TROUGH BEGINS TO
SHIFT EAST AND WE LOSE THE INSTABILITY...PCPN SHOULD TAPER OFF TO A
FEW SHOWERS THURSDAY NIGHT. COOLER AIR WILL BEGIN FILTERING INTO THE
AREA THROUGH THE DAY ON THURSDAY WITH HIGHS RANGING FROM THE UPPER
60S NORTHWEST TO LOW TO MID 70S SOUTHEAST.
SURFACE HIGH PRESSURE WILL BUILD DOWN FROM THE NORTH AND INTO OUR
AREA FRIDAY INTO SATURDAY...KEEPING A SEASONABLY COOL AIRMASS IN
PLACE THROUGH THE START OF THE WEEKEND. HIGHS ON FRIDAY WILL BE IN
THE MID TO UPPER 60S AND WITH THE SURFACE HIGH OVERHEAD...LOWS
SATURDAY MORNING WILL DIP INTO THE LOW TO MID 40S. THE SURFACE HIGH
WILL BEGIN TO SHIFT OFF TO THE EAST THROUGH THE REMAINDER OF THE
WEEKEND AS MID LEVEL RIDGING BEGINS TO ESTABLISH ITSELF ALOFT. THIS
WILL RESULT IN A GRADUAL RETURN TO WARMER TEMPERATURES THROUGH THE
REST OF THE HOLIDAY WEEKEND. MODELS ARE STILL TRYING TO SUGGEST THE
POSSIBILITY OF SOME ENERGY DROPPING DOWN FROM THE NORTHWEST LATE IN
THE WEEKEND. HOWEVER...TIMING AND PLACEMENT ARE HIGHLY VARIABLE SO
WILL MAINTAIN A DRY FORECAST AT THIS POINT.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
MVFR CEILINGS WILL PERSIST FOR A FEW MORE HOURS UNTIL MIXING
RAISES CLOUD HEIGHTS AND VISIBILITIES LATER THIS AFTERNOON. WINDS
WILL GUST CLOSE TO 20 KNOTS DURING THIS TIME AS WELL. BR MAY FORM
AGAIN TONIGHT AT LUK AND ILN UNDER LIGHT WINDS AND A HUMID AIRMASS.
DAY MAY SEE A FEW SHOWERS TONIGHT IF ACTIVITY TO THE WEST HOLDS
TOGETHER AS INDICATED ON THE NAM AND RAP MODELS. CONVECTION MAY
DEVELOP AT ALL SITES ON TUESDAY AS FORCING INCREASES AHEAD OF A
FRONTAL ZONE...WITH WIND GUSTS OVER 20 KNOTS EXPECTED.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM TUESDAY NIGHT THROUGH
THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
249 PM EDT MON MAY 20 2013
.SYNOPSIS...
UPPER TROUGH AXIS SLOWLY EXITS EAST TONIGHT. COLD FRONT APPROACHES
WEDNESDAY AND MOVES ACROSS THURSDAY. COOLER HIGH PRESSURE FRIDAY
AND THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
RADAR IMAGERY AT 18Z SHOWING SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS MAINLY CONFINED TO THE EASTERN HIGHER TERRAIN AT THIS
POINT. EXPECT THIS PRECIP TO CONTINUE EASTWARD AS THE S/W TROUGH AND
ASSOC VORT MAX RESPONSIBLE FOR TODAY/S PRECIP CONTINUES EAST AS
WELL. LATEST SFC OBS AND RUC13 CONTINUE TO DEPICT SOME SFC
CONVERGENCE WITH WEAK TROUGH ACROSS THE FAR WESTERN ZONES THIS
AFTERNOON. BEST LLVL MOISTURE HAS PUSHED EASTWARD AND NEAR-TERM
CONVECTIVE MODELS DO NOT SHOW ANY REDEVELOPMENT ACROSS THE WEST.
WILL HOWEVER GO AHEAD AND CONTINUE A SLIGHT CHANCE FOR CONVECTION
OUT HERE WITH JUST A PINCH OF LLVL MOISTURE STILL NOTED ON POINT
SOUNDINGS AND PWATS UP AROUND 1.2-1.4 INCHES.
DURING THE OVERNIGHT HOURS TODAY/S S/W TROUGH AND VORT MAX CONTINUE
EASTWARD. PRECIP WILL HAVE ENDED FOR MOST IF NOT ALL LOCATIONS BTWN
00Z-03Z TUE. MOST LOCATIONS WILL REMAIN PRECIP-FREE OVERNIGHT BUT
LATEST NWP GUIDANCE DEPICTING A 2-3KFT LAYER OF CONVECTIVE MOISTURE
PUSHING INTO THE NORTHERN ZONES CENTERED AROUND 850MB AND AROUND 12Z
TUE. SIMULTANEOUSLY 850MB CONVERGENCE NOTED ACROSS THE I-79 CORRIDOR
AS WELL AND THUS WILL BRING IN SLIGHT CHANCE POPS WITH THUNDER WITH
THIS FEATURE. INHERITED MINS IN THE LOW/MID 60S MOST LOWLAND
LOCATIONS LOOK GOOD. WILL CONTINUE TO CARRY AT LEAST A SLIGHT CHANCE
OF SHOWERS/THUNDER MOST LOCATION DURING THE DAY...BUT THE BETTER
CHANCE OF THUNDERSTORMS ARRIVES SE OHIO ZONES BY AND AFTER 21Z AS
BETTER LLVL MOISTURE ARRIVES WITH DECENT SFC CONVERGENCE NOTED SAME
AREA. SHEAR IS WEAK AND THUS ORGANIZATION WILL BE AS WELL WITH
REGARD TO SEVERE POTENTIAL. BUT HEAVY DOWNPOURS WILL BE POSSIBLE AND
WITH SOME STRONG WINDS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
MAIN WEATHER MAKER THROUGH THE SHORT TERM WILL BE THE SURFACE COLD
FRONT PASSING WEDNESDAY...AND THEN THE LINGER UPPER LEVEL TROUGH.
FOR TUESDAY NIGHT...MAIN FOCUS IS TO THE WEST...SO DECREASED POPS
SOME...HOWEVER WITH LOTS OF MOISTURE STILL HANGING AROUND COULD NOT
GO DRY SO HAVE SLIGHT CHANCE TO CHANCE POPS FOR MUCH OF THE AREA
OVERNIGHT. COLD FRONT APPROACHES FROM THE WEST WEDNESDAY...WILL
LIKELY BE ONGOING CONVECTION/OUTFLOW BOUNDARIES TO OUR WEST
WEDNESDAY MORNING. WE SHOULD HAVE PLENTY OF INSTABILITY IN THE
WARM SECTOR AHEAD OF THE FRONT...NAM IS SHOWING 2000+ J/KG CAPE
ALONG THE OHIO RIVER AROUND NOON...WITH 30-40KTS BULK SHEER AND
PWATS AROUND 1.5 INCHES. SHOULD SEE A ROUND OF ORGANIZED
CONVECTION OUT AHEAD OF THE COLD FRONT MOVING FROM WEST TO EAST
ACROSS THE CWA. THE MOST LIKELY AREA OF CONCERN FOR STRONG TO
SEVERE STORMS CONTINUES TO BE ALONG AND EITHER SIDE OF THE OHIO
RIVER FROM SE OHIO INTO NORTH CENTRAL WEST VIRGINIA. WILL CONTINUE
HWO MENTION FOR DAMAGING WINDS AND HAIL POTENTIAL. THE ACTUAL COLD
FRONT WILL NOT PASS UNTIL THURSDAY...SO POPS CONTINUE THROUGH THE
SHORT TERM PERIOD.
WEDNESDAY WILL BE A WARM DAY...BUT WITH PLENTY OF CLOUDS SHOULD NOT
BE AS WARM AS TUESDAY. THURSDAY WILL BE ABOUT 10 DEGREES COOLER.
OVERNIGHT LOWS WILL BE MILD WITH LOTS OF CLOUDS AND MOISTURE.
BASED ON RECENT VERIFICATION STATS...BLENDED IN BIAS- CORRECTED
CONSENSUS GUIDANCE FOR BOTH HIGHS AND LOWS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HAVE GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE FORECAST.
COLD FRONT SHOULD BE LOCATED SOUTHEAST OF THE REGION AT THE
BEGINNING OF THE PERIOD...WITH HIGH PRESSURE BUILDING IN. CHANCE
OF SHOWERS AND STORMS WILL END FROM THE NORTHWEST THURSDAY NIGHT
INTO FRIDAY. HOWEVER...A MID-LEVEL DISTURBANCE MOVING SOUTHEAST
WILL INCREASE THE CHANCES FOR PRECIPITATION ON FRIDAY....MAINLY IN
THE MOUNTAINS AND ADJACENT COUNTIES.
HIGH PRESSURE WILL THEN BE IN CONTROL OF THE AREA INTO MONDAY.
HOWEVER...A WEAK MID-LEVEL DISTURBANCE WILL SLIDE SOUTHEAST SATURDAY
NIGHT INTO SUNDAY.
A WARM FRONT WILL DEVELOP AND APPROACH THE REGION ON MONDAY. ECMWF
SUGGESTS THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY
AFTERNOON...ESPECIALLY ACROSS THE SOUTH. BECAUSE OF UNCERTAINTY...HAVE
LEFT THESE CHANCES OUT OF THE FORECAST FOR NOW.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
MVFR TO LOW VFR CIGS ACROSS MUCH OF THE AREA CURRENTLY SHOULD
SCATTER WEST TO EAST AS THE AFTERNOON PROGRESSES AS THE LAST OF
THE PRECIP CONTINUES TO PUSH EASTWARD. VIS MAY ONCE AGAIN BECOME AN
ISSUE OVERNIGHT AND TOWARDS DAWN...PARTICULARLY AT LOCATIONS WHICH
RECEIVED RAINFALL TODAY SUCH AS CRW AND EKN. EARLY MORNING REDUCED
VIS/LOW STRATUS SHOULD ONCE AGAIN GIVE WAY TO VFR CONDITIONS BY
MID-MORNING. WINDS GENERALLY REMAIN LIGHT OUT OF THE S/SW THROUGH
THE VALID PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: SOME UNCERTAINTY ON FOG DENSITY...LOW STRATUS...AND
AREAL COVERAGE OVERNIGHT AND EARLY MORNING TUESDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M H H H H H H H H H H H
HTS CONSISTENCY M H H H H H H H H H H H
BKW CONSISTENCY M H H H H H H H H H H H
EKN CONSISTENCY H H H M H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M M M H H H H H H H H H
AFTER 18Z TUESDAY...
IFR CONDITIONS POSSIBLE WEDNESDAY WITH SHOWERS AND THUNDERSTORMS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/MZ/50
NEAR TERM...50
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...50
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
142 PM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER RIDGE ACROSS THE AREA TODAY WILL MOVE EAST TONIGHT. A
WEAK WARM FRONT WILL MOVE ACROSS THE REGION TODAY. AN AREA OF LOW
PRESSURE OVER THE NORTHERN PLAINS WILL SLOWLY PROGRESS EASTWARD
ACROSS THE GREAT LAKES REGION THROUGH MID WEEK. THE AIRMASS WILL
BECOME INCREASINGLY MOIST AND UNSTABLE AS THIS FEATURE APPROACHES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SCATTERED MORNING SHOWERS HAVE ALL ENDED AFTER ONE ROBUST
THUNDERSTORM DEVELOPED OVER NORTHERN LORAIN COUNTY/LAKE ERIE. SPC
RUC ANALSYS SHOWS 2000-2500 J/KG OF ML CAPE OVER NORTHERN OHIO
BUT GFS SOUNDINGS STILL REFLECT A CAP IN PLACE BETWEEN 850-700MB.
A SEVERE THUNDERSTORM WATCH HAS RECENTLY BEEN ISSUED ACROSS MOST
OF MICHIGAN WHERE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FILL
IN DOWNWIND OF LAKE MICHIGAN WHERE BETTER LARGE SCALE FORCING IS
LOCATED. WE ARE CLOSER TO THE UPPER RIDGE AXIS AND HAVE AN
OVERALL LACK OF FORCING FOR ASCENT. IT WILL BE CLOSER TO EVENING
BEFORE THIS CONVECTION APPROACHES TOLEDO FROM THE NORTH. THE OTHER
AREA TO WATCH WILL BE NEAR THE LINGERING STRATUS WHERE
DIFFERENTIAL HEATING BOUNDARIES ARE DEVELOPING WITH TEMPERATURES
BENEATH THE CLOUD FIELD RUNNING AS MUCH AS 10 DEGREES COOLER. AT
THIS TIME NOT EXPECTING MUCH IN THE WAY OF THUNDERSTORMS FOR THE
AFTERNOON BUT WILL CONTINUE TO MONITOR. IF ANY THUNDERSTORMS
DEVELOP THEY WOULD HAVE THE POTENTIAL TO BE STRONG GIVEN THE
AVAILABLE INSTABILITY BUT HEAVY RAIN WOULD BE THE GREATEST THREAT
GIVEN THE SLOW MOVEMENT.
PREVIOUS DISCUSSION...TODAY IS A TOUGH FORECAST. THE HRRR AND
RUC/RAP MODELS HAVE BEEN FORECASTING A NARROW BAND OF
SHOWERS/THUNDERSTORMS TO DEVELOP OVER EASTERN INDIANA EARLY THIS
MORNING AND THEN MOVE EAST. AT 3 AM EDT THE ILN 88D WAS INDICATING
A FINE LINE OVER SE INDIANA. AS EACH HOUR HAS GONE ON THE MODELS
ARE DELAYING THE DEVELOPMENT AND INTENSITY OF THE PRECIPITATION.
NOW THEY DON`T HAVE ANY PRECIPITATION DEVELOPING ON THIS LINE
UNTIL AROUND 8 OR 9 AM MAINLY FROM CLE SOUTH. SOME OF THE RADAR
FORECAST OUTPUT FROM SPC STORM-SCALE ENSEMBLE OF OPPORTUNITY
MODELS ARE ALL OVER THE PLACE FOR TODAY...SOME WITH NO SHOWER OR
THUNDERSTORM DEVELOPMENT IN THE FORECAST AREA AND SOME WITH A
LITTLE DEVELOPMENT. THE 4KM WRF NMM MODEL HAS SOME ISOLATED
SHOWERS DEVELOPING. CONFIDENCE IS LOW IN THIS BECAUSE OF SO MUCH
RIDGING ALOFT...BUT WILL FORECAST A CHANCE OF SPRINKLES MAINLY
THIS AM AS THIS LINE MOVES THROUGH. WILL MONITOR THIS AND UPDATE
AS NEEDED.
ANY FOG THAT DEVELOPS THROUGH DAYBREAK SHOULD NOT BE SIGNIFICANT
ENOUGH TO BE MENTIONED IN THE ZONES/GRIDS.
NOT MUCH IN THE WAY OF CLOUDS ACROSS THE FORECAST AREA AT 4
AM...HOWEVER...THEY ARE EXPECTED TO DEVELOP THROUGH DAYBREAK.
PARTLY CLOUDY SHOULD HANDLE MOST OF TODAY.
OTHER THEN THIS NOT EXPECTING ANY SHOWERS AND THUNDERSTORMS TO
DEVELOP TODAY...THEY SHOULD HOLD OFF UNTIL AFTER 6 PM. NOT
EXPECTING MUCH OF A LAKE BREEZE AS THE GRADIENT WILL BE TOO
STRONG. ERIE MAY GET A LAKE BREEZE FOR A TIME THIS AFTERNOON. WENT
ON THE WARMER SIDE OF GUIDANCE FOR HIGHS BECAUSE OF AN INCREASING
SOUTHWEST FLOW AND WARMER AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER LOW AND SURFACE LOW NOW OVER THE NORTHERN PLAINS WILL
MOVE SLOWLY EAST AND BE OVER THE FORECAST AREA THURSDAY AND
THURSDAY NIGHT. IN THE MEANTIME THE CHALLENGE IS FIGURING OUT THE
SHOWER AND THUNDERSTORM CHANCES.
FOR TONIGHT THE UPPER RIDGE MOVES EAST AND WITH SOME MOISTURE AND A
WEAK IMPULSE MOVING THROUGH KEPT CHANCE POPS MAINLY OVER THE
NORTHERN PORTION OF THE FORECAST AREA. THE RADAR FORECAST FROM THE
4KM WRF NMM 00Z MODEL SEEMS REASONABLE WITH SOME THUNDERSTORMS
BRUSHING THE NORTHERN PORTION OF THE FORECAST AREA.
FOR TUESDAY CHANCE POPS MOST AREAS BUT DID CONTINUE LIKELY POPS
EXTREME NORTHWEST OHIO. ON THE EDGE ABOUT THAT BASED ON THE LACK
OF MOISTURE ALOFT. THE AIRMASS IS UNSTABLE. FOR TUESDAY NIGHT
AGAIN...CHANCE POPS AS THE AIRMASS IS BECOMING MORE MOIST AND
CONTINUED UNSTABLE. FOR WEDNESDAY INTO THURSDAY WITH THE FRONT
GETTING CLOSE WEDNESDAY AND THEN SAGGING THROUGH ON THURSDAY
LIKELY POPS AT TIMES LOOKS VERY GOOD. AS WE GET CLOSER WE WILL BE
ABLE TO PUT MORE RESOLUTION INTO THE FORECAST.
USED A BLEND OF GUIDANCE AND THE PREVIOUS FORECAST FOR THE HIGHS AND
LOWS. THE HIGHS TUESDAY AND WEDNESDAY ARE TRICKY IF WE GET TOO MUCH
CONVECTION AND CLOUDS THIS WILL HAVE A TREMENDOUS IMPACT ON THE
TEMPERATURES.
RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN INCH FOR THIS
WEEK...EXCEPT LOCALLY HIGHER AMOUNTS IN SOME THUNDERSTORMS.
THE AIRMASS FOR TONIGHT WILL BE SOMEWHAT DRY ALOFT AND THIS WILL
LEAD TO POSSIBLE SIGNIFICANT DOWNDRAFTS AS PER THE DELTA THETA E...WILL
MENTION THAT IN THE HAZARDOUS WEATHER OUTLOOK. WILL ALSO MENTION
RISK OF SEVERE TUESDAY THROUGH WEDNESDAY NIGHT ESPECIALLY.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LITTLE CHANGE IN THE EXTENDED. BOTH GFS AND ECMWF MOVE HIGH
PRESSURE OVER THE AREA FRIDAY...WHICH LINGERS THROUGH THE WEEKEND.
EXTENDED LOOKS DRY WITH MORE SEASONAL TEMPS THROUGH THE WEEKEND.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
AREA OF STRATUS OVER N-CENTRAL HAS LIFTED TO MVFR AND CONTINUES
TO ERODE FROM THE EDGES. EXPECT ALL AREAS TO BE VFR IN AN HOUR OR
TWO. STILL A LOT OF QUESTIONS ABOUT THUNDERSTORM ACTIVITY DURING
THE PERIOD. BEST GUESS RIGHT NOW IS THAT NW OH COULD SEE SOME
STORMS TOWARD EVENING. WILL GO WITH A MENTION OVER ABOUT THE WEST
HALF OF THE AREA. EASTERN AREAS SHOULD BE CAPPED AND WILL REMAIN
DRY THROUGH 18Z TUESDAY. ANOTHER ROUND OF STORMS COULD AFFECT
WESTERN AREAS BY MIDDAY TUESDAY. S TO SW FLOW WILL CONTINUE.
SPEEDS SHOULD BE 5 KNOTS OR LESS LATER TONIGHT WHICH SHOULD ALLOW
SOME PATCHY MVFR FOG TO DEVELOP BEFORE DAYBREAK. SPEEDS WILL
INCREASE ON TUESDAY MORNING WITH GUSTS TO 20 KNOTS LIKELY. KERI
ALREADLY HAS A LAKE BREEZE. DO NOT THINK IT WILL REACH KCLE TODAY.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS OVERNIGHT THROUGH
THURSDAY.
&&
.MARINE...
PREDOMINATELY A SOUTH TO SOUTHEAST FLOW TODAY ALTHOUGH COULD SEE A
WEAK LAKE BREEZE EAST HALF FOR A FEW HOURS. EXPECT SOUTHWEST FLOW
TO DEVELOP TOMORROW AHEAD OF NEXT SYSTEM. MODELS IN GOOD AGREEMENT
PUSHING THE NEXT FRONT THROUGH ON THURSDAY. WITH NORTH TO NORTHEAST
FLOW DEVELOPING BEHIND THE SYSTEM WILL APPROACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KEC/KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...DJB
AVIATION...KUBINA
MARINE...DJB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
141 PM EDT MON MAY 20 2013
.SYNOPSIS...
A MID LEVEL RIDGE WILL BUILD ACROSS THE REGION TODAY. THE RIDGE
WILL MOVE EAST TONIGHT AS A LARGE UPPER LEVEL LOW OVER THE
NORTHERN PLAINS BEGINS TO MAKE A SLOW PROGRESSION TO THE EAST.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL INCREASE TUESDAY
INTO WEDNESDAY AS THE LOW CONTINUES TOWARD THE GREAT LAKES. A COLD
FRONT WILL EVENTUALLY PUSH THROUGH OUR AREA WEDNESDAY INTO WEDNESDAY
NIGHT. ABOVE NORMAL TEMPERATURES ALONG WITH A HUMID AIRMASS WILL
REMAIN IN PLACE UNTIL AFTER FRONTAL PASSAGE.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE UPDATED POPS TO LIKELY EAST OF COLUMBUS WHERE LINE OF
THUNDERSTORMS DEVELOPED ALONG A WEAK NORTH-SOUTH ORIENTED
BOUNDARY.
FOR THIS AFTERNOON...A VERY WARM AND HUMID AIRMASS WILL PREVAIL.
WITH THE RIDGE IN PLACE...CONVECTION SHOULD BE HELD AT BAY.
HOWEVER...WITH MODERATE TO STRONG INSTABILITY ALONG WITH A VERY
WEAK CAP...IT IS NOT OUT OF THE QUESTION THAT AN ISOLATED SHOWER
OR STORM COULD POP. GIVEN THAT THIS CHANCE IS ABOUT 10
PERCENT...HAVE LEFT THE FORECAST DRY FOR THE AFTERNOON HOURS.
HIGHS TODAY WILL WARM INTO THE UPPER 80S WITH A FEW SPOTS POSSIBLY
REACHING 90 DEGREES BEFORE THE AFTERNOON IS THROUGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
HAVE USED A BLEND OF THE GFS...CMC AND ECMWF FOR THE SHORT TERM
FORECAST.
MID LVL RIDGE WILL MOVE EAST TONIGHT AS A LARGE UPR LVL LOW OVER
THE NORTHERN PLAINS PUSHES SLOWLY EAST TOWARD THE GREAT LAKES.
CHANCES OF SHOWERS AND THUNDERSTORMS WILL ENCROACH THE WESTERN
ZONES AS MODELS SUGGEST THAT A WEAKENING COMPLEX APPROACHES THE
REGION.
ON TUESDAY...VERY WARM AND HUMID CONDITIONS WILL CONTINUE. TIMING
AND COVERAGE OF CONVECTION WILL BE DEPENDENT ON PREVIOUS FEATURE
MOVING INTO THE AREA WHICH IS STILL SKETCHY AT THIS TIME. AS A
RESULT...HAVE GONE WITH CHANCE POPS. GIVEN INCREASING SHEAR AND
MODERATE TO STRONG INSTABILITY...A FEW SEVERE STORMS WILL BE
POSSIBLE.
FOR TUESDAY NIGHT...THE THREAT FOR SHOWERS/STORMS WILL
CONTINUE...BUT MODELS SUGGEST THAT WE MAY BE IN A RELATIVE LULL
BEFORE A MORE BONAFIDE S/WV AND ASSOCIATED COLD FRONT AFFECT THE
REGION ON WEDNESDAY.
FOR WEDNESDAY INTO WEDNESDAY NIGHT...UPR LVL LOW WILL DROP
SOUTHEAST INTO THE GREAT LAKES. AS MENTIONED...A MORE BONAFIDE
S/WV IS EXPECTED TO ROTATE NE ACROSS THE AREA ALONG WITH A SFC
COLD FRONT. ALTHOUGH SHEAR WILL BE MODERATE...INSTABILITY WILL BE
A LITTLE LESS THAN TUESDAY GIVEN CLOUDS AND SLIGHTLY COOLER
TEMPERATURES. EVEN SO...CAN NOT RULE OUT A FEW SEVERE STORMS
DURING THE AFTERNOON INTO THE EVENING HOURS.
ON THURSDAY...UPR LVL LOW WILL DROP SE INTO OUR AREA. MODELS
SUGGEST THAT A SECONDARY COLD FRONT/TROUGH AXIS WILL APPROACH THE
REGION FROM THE NORTHWEST...KEEPING THE THREAT FOR SHOWERS AND
ISOLATED STORMS. TEMPERATURES WILL BE COOLER GIVEN CLOUDS AND CAA
WITH HIGHS RANGING FROM THE UPPER 60S NW TO THE MID 70S SOUTHEAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
AS THE SECONDARY FRONT/TROUGH AXIS SHIFTS SOUTH THURSDAY NIGHT...
PCPN SHOULD TAPER OFF FROM NORTH TO SOUTH.
HIGH PRESSURE AND A COOLER AIRMASS WILL BUILD DOWN FROM THE NORTH
THROUGH THE DAY ON FRIDAY. THIS WILL LEAD TO SLIGHTLY BELOW NORMAL
TEMPERATURES WITH HIGHS ON FRIDAY IN THE UPPER 60S TO LOWER 70S. THE
AIRMASS WILL THEN SLOWLY MODERATE THROUGH THE WEEKEND AS MID LEVEL
RIDGING BEGINS TO WORK IN FROM THE WEST. BY SUNDAY...TEMPERATURES
WILL BE BACK TO NEAR NORMAL WITH HIGHS PUSHING BACK TOWARD THE MID
70S. WILL MAINTAIN A DRY FORECAST THROUGH THE WEEKEND AT THIS POINT
BUT THE 12Z ECMWF AND TO A LESSER EXTENT THE 12Z GFS ARE HINTING AT
THE POSSIBILITY OF SOME SHORT WAVE ENERGY DROPPING DOWN IN NORTHWEST
FLOW LATE IN THE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
MVFR CEILINGS WILL PERSIST FOR A FEW MORE HOURS UNTIL MIXING
RAISES CLOUD HEIGHTS AND VISIBILITIES LATER THIS AFTERNOON. WINDS
WILL GUST CLOSE TO 20 KNOTS DURING THIS TIME AS WELL. BR MAY FORM
AGAIN TONIGHT AT LUK AND ILN UNDER LIGHT WINDS AND A HUMID AIRMASS.
DAY MAY SEE A FEW SHOWERS TONIGHT IF ACTIVITY TO THE WEST HOLDS
TOGETHER AS INDICATED ON THE NAM AND RAP MODELS. CONVECTION MAY
DEVELOP AT ALL SITES ON TUESDAY AS FORCING INCREASES AHEAD OF A
FRONTAL ZONE...WITH WIND GUSTS OVER 20 KNOTS EXPECTED.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM TUESDAY NIGHT THROUGH
THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...CONIGLIO/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/JGL
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
956 AM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER RIDGE ACROSS THE AREA TODAY WILL MOVE EAST TONIGHT. A
WEAK WARM FRONT WILL MOVE ACROSS THE REGION TODAY. AN AREA OF LOW
PRESSURE OVER THE NORTHERN PLAINS WILL SLOWLY PROGRESS EASTWARD
ACROSS THE GREAT LAKES REGION THROUGH MID WEEK. THE AIRMASS WILL
BECOME INCREASINGLY MOIST AND UNSTABLE AS THIS FEATURE APPROACHES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A BROKEN LINE OF SHOWERS IS STARTING TO DEVELOP EXTENDING FROM
NORTH CENTRAL MICHIGAN TO WESTERN VIRGINIA. THE CU FIELD CONTINUES
TO DEVELOP ACROSS OUR WESTERN COUNTIES ALONG A NARROW CORRIDOR OF
THETA-E ADVECTION NEAR 850MB AND EXPECT AT LEAST SCATTERED
SHOWERS TO DEVELOP AND MOVE EAST. MU CAPES ARE NEAR 2000 J/KG WITH
STEEPENING MID-LEVEL LAPSE RATES APPROACHING 7 C/KM SO THUNDER
WILL ALSO BE POSSIBLE. EXPECT THE TREND THROUGH EARLY AFTERNOON TO BE FOR
THIS THETA-E RIDGE TO LIFT NORTH ACROSS LAKE ERIE SO ONLY CARRIED
THE CHANCE OF SHOWERS AND THUNDERSTORMS EAST TO ABOUT
CLEVELAND...WITH DECREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THE AFTERNOON. LEANING TOWARDS THE GFS SOUNDING WHICH ARE
WARMER ALOFT THOUGH 700MB TODAY AND MORE IN LINE WITH THE 12Z ILN
SOUNDING...SUGGESTING WE WILL BE CAPPED FOR THE AFTERNOON. WE WILL
HAVE TO KEEP AN EYE ON THE RADAR THOUGH AS DEWPOINTS ARE ALREADY
IN THE UPPER 60S IN SOME AREAS.
PREVIOUS DISCUSSION...TODAY IS A TOUGH FORECAST. THE HRRR AND
RUC/RAP MODELS HAVE BEEN FORECASTING A NARROW BAND OF
SHOWERS/THUNDERSTORMS TO DEVELOP OVER EASTERN INDIANA EARLY THIS
MORNING AND THEN MOVE EAST. AT 3 AM EDT THE ILN 88D WAS INDICATING
A FINE LINE OVER SE INDIANA. AS EACH HOUR HAS GONE ON THE MODELS
ARE DELAYING THE DEVELOPMENT AND INTENSITY OF THE PRECIPITATION.
NOW THEY DON`T HAVE ANY PRECIPITATION DEVELOPING ON THIS LINE
UNTIL AROUND 8 OR 9 AM MAINLY FROM CLE SOUTH. SOME OF THE RADAR
FORECAST OUTPUT FROM SPC STORM-SCALE ENSEMBLE OF OPPORTUNITY
MODELS ARE ALL OVER THE PLACE FOR TODAY...SOME WITH NO SHOWER OR
THUNDERSTORM DEVELOPMENT IN THE FORECAST AREA AND SOME WITH A
LITTLE DEVELOPMENT. THE 4KM WRF NMM MODEL HAS SOME ISOLATED
SHOWERS DEVELOPING. CONFIDENCE IS LOW IN THIS BECAUSE OF SO MUCH
RIDGING ALOFT...BUT WILL FORECAST A CHANCE OF SPRINKLES MAINLY
THIS AM AS THIS LINE MOVES THROUGH. WILL MONITOR THIS AND UPDATE
AS NEEDED.
ANY FOG THAT DEVELOPS THROUGH DAYBREAK SHOULD NOT BE SIGNIFICANT
ENOUGH TO BE MENTIONED IN THE ZONES/GRIDS.
NOT MUCH IN THE WAY OF CLOUDS ACROSS THE FORECAST AREA AT 4
AM...HOWEVER...THEY ARE EXPECTED TO DEVELOP THROUGH DAYBREAK.
PARTLY CLOUDY SHOULD HANDLE MOST OF TODAY.
OTHER THEN THIS NOT EXPECTING ANY SHOWERS AND THUNDERSTORMS TO
DEVELOP TODAY...THEY SHOULD HOLD OFF UNTIL AFTER 6 PM. NOT
EXPECTING MUCH OF A LAKE BREEZE AS THE GRADIENT WILL BE TOO
STRONG. ERIE MAY GET A LAKE BREEZE FOR A TIME THIS AFTERNOON. WENT
ON THE WARMER SIDE OF GUIDANCE FOR HIGHS BECAUSE OF AN INCREASING
SOUTHWEST FLOW AND WARMER AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER LOW AND SURFACE LOW NOW OVER THE NORTHERN PLAINS WILL
MOVE SLOWLY EAST AND BE OVER THE FORECAST AREA THURSDAY AND
THURSDAY NIGHT. IN THE MEANTIME THE CHALLENGE IS FIGURING OUT THE
SHOWER AND THUNDERSTORM CHANCES.
FOR TONIGHT THE UPPER RIDGE MOVES EAST AND WITH SOME MOISTURE AND A
WEAK IMPULSE MOVING THROUGH KEPT CHANCE POPS MAINLY OVER THE
NORTHERN PORTION OF THE FORECAST AREA. THE RADAR FORECAST FROM THE
4KM WRF NMM 00Z MODEL SEEMS REASONABLE WITH SOME THUNDERSTORMS
BRUSHING THE NORTHERN PORTION OF THE FORECAST AREA.
FOR TUESDAY CHANCE POPS MOST AREAS BUT DID CONTINUE LIKELY POPS
EXTREME NORTHWEST OHIO. ON THE EDGE ABOUT THAT BASED ON THE LACK
OF MOISTURE ALOFT. THE AIRMASS IS UNSTABLE. FOR TUESDAY NIGHT
AGAIN...CHANCE POPS AS THE AIRMASS IS BECOMING MORE MOIST AND
CONTINUED UNSTABLE. FOR WEDNESDAY INTO THURSDAY WITH THE FRONT
GETTING CLOSE WEDNESDAY AND THEN SAGGING THROUGH ON THURSDAY
LIKELY POPS AT TIMES LOOKS VERY GOOD. AS WE GET CLOSER WE WILL BE
ABLE TO PUT MORE RESOLUTION INTO THE FORECAST.
USED A BLEND OF GUIDANCE AND THE PREVIOUS FORECAST FOR THE HIGHS AND
LOWS. THE HIGHS TUESDAY AND WEDNESDAY ARE TRICKY IF WE GET TOO MUCH
CONVECTION AND CLOUDS THIS WILL HAVE A TREMENDOUS IMPACT ON THE
TEMPERATURES.
RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN INCH FOR THIS
WEEK...EXCEPT LOCALLY HIGHER AMOUNTS IN SOME THUNDERSTORMS.
THE AIRMASS FOR TONIGHT WILL BE SOMEWHAT DRY ALOFT AND THIS WILL
LEAD TO POSSIBLE SIGNIFICANT DOWNDRAFTS AS PER THE DELTA THETA E...WILL
MENTION THAT IN THE HAZARDOUS WEATHER OUTLOOK. WILL ALSO MENTION
RISK OF SEVERE TUESDAY THROUGH WEDNESDAY NIGHT ESPECIALLY.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LITTLE CHANGE IN THE EXTENDED. BOTH GFS AND ECMWF MOVE HIGH
PRESSURE OVER THE AREA FRIDAY...WHICH LINGERS THROUGH THE WEEKEND.
EXTENDED LOOKS DRY WITH MORE SEASONAL TEMPS THROUGH THE WEEKEND.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
PATCHY MVFR BR WILL BURNOFF QUICKLY THIS MORNING. POTENTIAL EXISTS
FOR SCATTERED TSRA NW OH LATE THIS AFTERNOON AS CAPES APPROACH
3000 J/KG. CONFIDENCE IS STILL LOW AS TO EXACTLY WHERE AND WHEN
SCATTERED TSRA WILL DEVELOP AS STRONG RIDGE REMAINS OVERHEAD AND
SEE NO TRIGGER. MUCH BETTER CHANCE OF TSRA OVERNIGHT TONIGHT.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS OVERNIGHT THROUGH
THURSDAY.
&&
.MARINE...
PREDOMINATELY A SOUTH TO SOUTHEAST FLOW TODAY ALTHOUGH COULD SEE A
WEAK LAKE BREEZE EAST HALF FOR A FEW HOURS. EXPECT SOUTHWEST FLOW
TO DEVELOP TOMORROW AHEAD OF NEXT SYSTEM. MODELS IN GOOD AGREEMENT
PUSHING THE NEXT FRONT THROUGH ON THURSDAY. WITH NORTH TO NORTHEAST
FLOW DEVELOPING BEHIND THE SYSTEM WILL APPROACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KEC/KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
716 AM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER RIDGE ACROSS THE AREA TODAY WILL MOVE EAST TONIGHT. A
WEAK WARM FRONT WILL MOVE ACROSS THE REGION TODAY. AN AREA OF LOW
PRESSURE OVER THE NORTHERN PLAINS WILL SLOWLY PROGRESS EASTWARD
ACROSS THE GREAT LAKES REGION THROUGH MID WEEK. THE AIRMASS WILL
BECOME INCREASINGLY MOIST AND UNSTABLE AS THIS FEATURE APPROACHES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLOUDS ARE ON THE INCREASE AS PER THE MODELS. THE THREAT FOR
SPRINKLES STILL SEEMS OK WITH LOW CLOUDS DEVELOPING...SO CONTINUED IT.
THE THREAT FOR SHOWERS AND THUNDERSTORMS THIS AM SEEMED TO HAVE
ENDED ACCORDING TO THE MODELS AND LOOKING AT SATELLITE PICTURES...RADAR
ETC. ADDED PATCHY DENSE FOG TO A FEW AREAS SOUTH OF CLEVELAND.
PREVIOUS DISCUSSION...TODAY IS A TOUGH FORECAST. THE HRRR AND
RUC/RAP MODELS HAVE BEEN FORECASTING A NARROW BAND OF
SHOWERS/THUNDERSTORMS TO DEVELOP OVER EASTERN INDIANA EARLY THIS
MORNING AND THEN MOVE EAST. AT 3 AM EDT THE ILN 88D WAS INDICATING
A FINE LINE OVER SE INDIANA. AS EACH HOUR HAS GONE ON THE MODELS
ARE DELAYING THE DEVELOPMENT AND INTENSITY OF THE PRECIPITATION.
NOW THEY DON`T HAVE ANY PRECIPITATION DEVELOPING ON THIS LINE
UNTIL AROUND 8 OR 9 AM MAINLY FROM CLE SOUTH. SOME OF THE RADAR
FORECAST OUTPUT FROM SPC STORM-SCALE ENSEMBLE OF OPPORTUNITY
MODELS ARE ALL OVER THE PLACE FOR TODAY...SOME WITH NO SHOWER OR
THUNDERSTORM DEVELOPMENT IN THE FORECAST AREA AND SOME WITH A
LITTLE DEVELOPMENT. THE 4KM WRF NMM MODEL HAS SOME ISOLATED
SHOWERS DEVELOPING. CONFIDENCE IS LOW IN THIS BECAUSE OF SO MUCH
RIDGING ALOFT...BUT WILL FORECAST A CHANCE OF SPRINKLES MAINLY
THIS AM AS THIS LINE MOVES THROUGH. WILL MONITOR THIS AND UPDATE
AS NEEDED.
ANY FOG THAT DEVELOPS THROUGH DAYBREAK SHOULD NOT BE SIGNIFICANT
ENOUGH TO BE MENTIONED IN THE ZONES/GRIDS.
NOT MUCH IN THE WAY OF CLOUDS ACROSS THE FORECAST AREA AT 4
AM...HOWEVER...THEY ARE EXPECTED TO DEVELOP THROUGH DAYBREAK.
PARTLY CLOUDY SHOULD HANDLE MOST OF TODAY.
OTHER THEN THIS NOT EXPECTING ANY SHOWERS AND THUNDERSTORMS TO
DEVELOP TODAY...THEY SHOULD HOLD OFF UNTIL AFTER 6 PM. NOT
EXPECTING MUCH OF A LAKE BREEZE AS THE GRADIENT WILL BE TOO
STRONG. ERIE MAY GET A LAKE BREEZE FOR A TIME THIS AFTERNOON. WENT
ON THE WARMER SIDE OF GUIDANCE FOR HIGHS BECAUSE OF AN INCREASING
SOUTHWEST FLOW AND WARMER AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER LOW AND SURFACE LOW NOW OVER THE NORTHERN PLAINS WILL
MOVE SLOWLY EAST AND BE OVER THE FORECAST AREA THURSDAY AND
THURSDAY NIGHT. IN THE MEANTIME THE CHALLENGE IS FIGURING OUT THE
SHOWER AND THUNDERSTORM CHANCES.
FOR TONIGHT THE UPPER RIDGE MOVES EAST AND WITH SOME MOISTURE AND A
WEAK IMPULSE MOVING THROUGH KEPT CHANCE POPS MAINLY OVER THE
NORTHERN PORTION OF THE FORECAST AREA. THE RADAR FORECAST FROM THE
4KM WRF NMM 00Z MODEL SEEMS REASONABLE WITH SOME THUNDERSTORMS
BRUSHING THE NORTHERN PORTION OF THE FORECAST AREA.
FOR TUESDAY CHANCE POPS MOST AREAS BUT DID CONTINUE LIKELY POPS
EXTREME NORTHWEST OHIO. ON THE EDGE ABOUT THAT BASED ON THE LACK
OF MOISTURE ALOFT. THE AIRMASS IS UNSTABLE. FOR TUESDAY NIGHT
AGAIN...CHANCE POPS AS THE AIRMASS IS BECOMING MORE MOIST AND
CONTINUED UNSTABLE. FOR WEDNESDAY INTO THURSDAY WITH THE FRONT
GETTING CLOSE WEDNESDAY AND THEN SAGGING THROUGH ON THURSDAY
LIKELY POPS AT TIMES LOOKS VERY GOOD. AS WE GET CLOSER WE WILL BE
ABLE TO PUT MORE RESOLUTION INTO THE FORECAST.
USED A BLEND OF GUIDANCE AND THE PREVIOUS FORECAST FOR THE HIGHS AND
LOWS. THE HIGHS TUESDAY AND WEDNESDAY ARE TRICKY IF WE GET TOO MUCH
CONVECTION AND CLOUDS THIS WILL HAVE A TREMENDOUS IMPACT ON THE
TEMPERATURES.
RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN INCH FOR THIS
WEEK...EXCEPT LOCALLY HIGHER AMOUNTS IN SOME THUNDERSTORMS.
THE AIRMASS FOR TONIGHT WILL BE SOMEWHAT DRY ALOFT AND THIS WILL
LEAD TO POSSIBLE SIGNIFICANT DOWNDRAFTS AS PER THE DELTA THETA E...WILL
MENTION THAT IN THE HAZARDOUS WEATHER OUTLOOK. WILL ALSO MENTION
RISK OF SEVERE TUESDAY THROUGH WEDNESDAY NIGHT ESPECIALLY.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LITTLE CHANGE IN THE EXTENDED. BOTH GFS AND ECMWF MOVE HIGH
PRESSURE OVER THE AREA FRIDAY...WHICH LINGERS THROUGH THE WEEKEND.
EXTENDED LOOKS DRY WITH MORE SEASONAL TEMPS THROUGH THE WEEKEND.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
PATCHY MVFR BR WILL BURNOFF QUICKLY THIS MORNING. POTENTIAL EXISTS
FOR SCATTERED TSRA NW OH LATE THIS AFTERNOON AS CAPES APPROACH
3000 J/KG. CONFIDENCE IS STILL LOW AS TO EXACTLY WHERE AND WHEN
SCATTERED TSRA WILL DEVELOP AS STRONG RIDGE REMAINS OVERHEAD AND
SEE NO TRIGGER. MUCH BETTER CHANCE OF TSRA OVERNIGHT TONIGHT.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS OVERNIGHT THROUGH
THURSDAY.
&&
.MARINE...
PREDOMINATELY A SOUTH TO SOUTHEAST FLOW TODAY ALTHOUGH COULD SEE A
WEAK LAKE BREEZE EAST HALF FOR A FEW HOURS. EXPECT SOUTHWEST FLOW
TO DEVELOP TOMORROW AHEAD OF NEXT SYSTEM. MODELS IN GOOD AGREEMENT
PUSHING THE NEXT FRONT THROUGH ON THURSDAY. WITH NORTH TO NORTHEAST
FLOW DEVELOPING BEHIND THE SYSTEM WILL APPROACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
624 AM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER RIDGE ACROSS THE AREA TODAY WILL MOVE EAST TONIGHT. A
WEAK WARM FRONT WILL MOVE ACROSS THE REGION TODAY. AN AREA OF LOW
PRESSURE OVER THE NORTHERN PLAINS WILL SLOWLY PROGRESS EASTWARD
ACROSS THE GREAT LAKES REGION THROUGH MID WEEK. THE AIRMASS WILL
BECOME INCREASINGLY MOIST AND UNSTABLE AS THIS FEATURE APPROACHES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLOUDS ARE ON THE INCREASE AS PER THE MODELS. THE THREAT FOR
SPRINKLES STILL SEEMS OK WITH LOW CLOUDS DEVELOPING...SO CONTINUED IT.
THE THREAT FOR SHOWERS AND THUNDERSTORMS THIS AM SEEMED TO HAVE
ENDED ACCORDING TO THE MODELS AND LOOKING AT SATELLITE PICTURES...RADAR
ETC. ADDED PATCHY DENSE FOG TO A FEW AREAS SOUTH OF CLEVELAND.
PREVIOUS DISCUSSION...TODAY IS A TOUGH FORECAST. THE HRRR AND
RUC/RAP MODELS HAVE BEEN FORECASTING A NARROW BAND OF
SHOWERS/THUNDERSTORMS TO DEVELOP OVER EASTERN INDIANA EARLY THIS
MORNING AND THEN MOVE EAST. AT 3 AM EDT THE ILN 88D WAS INDICATING
A FINE LINE OVER SE INDIANA. AS EACH HOUR HAS GONE ON THE MODELS
ARE DELAYING THE DEVELOPMENT AND INTENSITY OF THE PRECIPITATION.
NOW THEY DON`T HAVE ANY PRECIPITATION DEVELOPING ON THIS LINE
UNTIL AROUND 8 OR 9 AM MAINLY FROM CLE SOUTH. SOME OF THE RADAR
FORECAST OUTPUT FROM SPC STORM-SCALE ENSEMBLE OF OPPORTUNITY
MODELS ARE ALL OVER THE PLACE FOR TODAY...SOME WITH NO SHOWER OR
THUNDERSTORM DEVELOPMENT IN THE FORECAST AREA AND SOME WITH A
LITTLE DEVELOPMENT. THE 4KM WRF NMM MODEL HAS SOME ISOLATED
SHOWERS DEVELOPING. CONFIDENCE IS LOW IN THIS BECAUSE OF SO MUCH
RIDGING ALOFT...BUT WILL FORECAST A CHANCE OF SPRINKLES MAINLY
THIS AM AS THIS LINE MOVES THROUGH. WILL MONITOR THIS AND UPDATE
AS NEEDED.
ANY FOG THAT DEVELOPS THROUGH DAYBREAK SHOULD NOT BE SIGNIFICANT
ENOUGH TO BE MENTIONED IN THE ZONES/GRIDS.
NOT MUCH IN THE WAY OF CLOUDS ACROSS THE FORECAST AREA AT 4
AM...HOWEVER...THEY ARE EXPECTED TO DEVELOP THROUGH DAYBREAK.
PARTLY CLOUDY SHOULD HANDLE MOST OF TODAY.
OTHER THEN THIS NOT EXPECTING ANY SHOWERS AND THUNDERSTORMS TO
DEVELOP TODAY...THEY SHOULD HOLD OFF UNTIL AFTER 6 PM. NOT
EXPECTING MUCH OF A LAKE BREEZE AS THE GRADIENT WILL BE TOO
STRONG. ERIE MAY GET A LAKE BREEZE FOR A TIME THIS AFTERNOON. WENT
ON THE WARMER SIDE OF GUIDANCE FOR HIGHS BECAUSE OF AN INCREASING
SOUTHWEST FLOW AND WARMER AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER LOW AND SURFACE LOW NOW OVER THE NORTHERN PLAINS WILL
MOVE SLOWLY EAST AND BE OVER THE FORECAST AREA THURSDAY AND
THURSDAY NIGHT. IN THE MEANTIME THE CHALLENGE IS FIGURING OUT THE
SHOWER AND THUNDERSTORM CHANCES.
FOR TONIGHT THE UPPER RIDGE MOVES EAST AND WITH SOME MOISTURE AND A
WEAK IMPULSE MOVING THROUGH KEPT CHANCE POPS MAINLY OVER THE
NORTHERN PORTION OF THE FORECAST AREA. THE RADAR FORECAST FROM THE
4KM WRF NMM 00Z MODEL SEEMS REASONABLE WITH SOME THUNDERSTORMS
BRUSHING THE NORTHERN PORTION OF THE FORECAST AREA.
FOR TUESDAY CHANCE POPS MOST AREAS BUT DID CONTINUE LIKELY POPS
EXTREME NORTHWEST OHIO. ON THE EDGE ABOUT THAT BASED ON THE LACK
OF MOISTURE ALOFT. THE AIRMASS IS UNSTABLE. FOR TUESDAY NIGHT
AGAIN...CHANCE POPS AS THE AIRMASS IS BECOMING MORE MOIST AND
CONTINUED UNSTABLE. FOR WEDNESDAY INTO THURSDAY WITH THE FRONT
GETTING CLOSE WEDNESDAY AND THEN SAGGING THROUGH ON THURSDAY
LIKELY POPS AT TIMES LOOKS VERY GOOD. AS WE GET CLOSER WE WILL BE
ABLE TO PUT MORE RESOLUTION INTO THE FORECAST.
USED A BLEND OF GUIDANCE AND THE PREVIOUS FORECAST FOR THE HIGHS AND
LOWS. THE HIGHS TUESDAY AND WEDNESDAY ARE TRICKY IF WE GET TOO MUCH
CONVECTION AND CLOUDS THIS WILL HAVE A TREMENDOUS IMPACT ON THE
TEMPERATURES.
RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN INCH FOR THIS
WEEK...EXCEPT LOCALLY HIGHER AMOUNTS IN SOME THUNDERSTORMS.
THE AIRMASS FOR TONIGHT WILL BE SOMEWHAT DRY ALOFT AND THIS WILL
LEAD TO POSSIBLE SIGNIFICANT DOWNDRAFTS AS PER THE DELTA THETA E...WILL
MENTION THAT IN THE HAZARDOUS WEATHER OUTLOOK. WILL ALSO MENTION
RISK OF SEVERE TUESDAY THROUGH WEDNESDAY NIGHT ESPECIALLY.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LITTLE CHANGE IN THE EXTENDED. BOTH GFS AND ECMWF MOVE HIGH
PRESSURE OVER THE AREA FRIDAY...WHICH LINGERS THROUGH THE WEEKEND.
EXTENDED LOOKS DRY WITH MORE SEASONAL TEMPS THROUGH THE WEEKEND.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
WITH DEW POINTS CREEPING INTO THE 60S DO EXPECT MORE MVFR BR THIS
MORNING...BUT WIND SHOULD HELP IT FROM BEING TOO WIDESPREAD. SHORT
TERM MODELS NOT IN AGREEMENT ON THE TSRA IN ILLINOIS...LATEST HRRR
MOVE TSRA INTO NW OH BY 12Z. FOR NOW WILL ONLY ADD VCTS TO TOL AND
FDY SINCE CONFIDENCE IS LOW AT THIS TIME.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS MONDAY
EVENING THROUGH THURSDAY.
&&
.MARINE...
PREDOMINATELY A SOUTH TO SOUTHEAST FLOW TODAY ALTHOUGH COULD SEE A
WEAK LAKE BREEZE EAST HALF FOR A FEW HOURS. EXPECT SOUTHWEST FLOW
TO DEVELOP TOMORROW AHEAD OF NEXT SYSTEM. MODELS IN GOOD AGREEMENT
PUSHING THE NEXT FRONT THROUGH ON THURSDAY. WITH NORTH TO NORTHEAST
FLOW DEVELOPING BEHIND THE SYSTEM WILL APPROACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION...CORRECTED
NWS CLEVELAND OH
359 AM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER RIDGE ACROSS THE AREA TODAY WILL MOVE EAST TONIGHT. A
WEAK WARM FRONT WILL MOVE ACROSS THE REGION TODAY. AN AREA OF LOW
PRESSURE OVER THE NORTHERN PLAINS WILL SLOWLY PROGRESS EASTWARD
ACROSS THE GREAT LAKES REGION THROUGH MID WEEK. THE AIRMASS WILL
BECOME INCREASINGLY MOIST AND UNSTABLE AS THIS FEATURE APPROACHES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY IS A TOUGH FORECAST. THE HRRR AND RUC/RAP MODELS HAVE BEEN
FORECASTING A NARROW BAND OF SHOWERS/THUNDERSTORMS TO DEVELOP OVER
EASTERN INDIANA EARLY THIS MORNING AND THEN MOVE EAST. AT 3 AM EDT
THE ILN 88D WAS INDICATING A FINE LINE OVER SE INDIANA. AS EACH HOUR
HAS GONE ON THE MODELS ARE DELAYING THE DEVELOPMENT AND INTENSITY OF
THE PRECIPITATION. NOW THEY DON`T HAVE ANY PRECIPITATION DEVELOPING
ON THIS LINE UNTIL AROUND 8 OR 9 AM MAINLY FROM CLE SOUTH.
SOME OF THE RADAR FORECAST OUTPUT FROM SPC STORM-SCALE
ENSEMBLE OF OPPORTUNITY MODELS ARE ALL OVER THE PLACE FOR
TODAY...SOME WITH NO SHOWER OR THUNDERSTORM DEVELOPMENT IN THE
FORECAST AREA AND SOME WITH A LITTLE DEVELOPMENT. THE 4KM WRF NMM
MODEL HAS SOME ISOLATED SHOWERS DEVELOPING. CONFIDENCE IS LOW IN
THIS BECAUSE OF SO MUCH RIDGING ALOFT...BUT WILL FORECAST A CHANCE
OF SPRINKLES MAINLY THIS AM AS THIS LINE MOVES THROUGH. WILL
MONITOR THIS AND UPDATE AS NEEDED.
ANY FOG THAT DEVELOPS THROUGH DAYBREAK SHOULD NOT BE SIGNIFICANT
ENOUGH TO BE MENTIONED IN THE ZONES/GRIDS.
NOT MUCH IN THE WAY OF CLOUDS ACROSS THE FORECAST AREA AT 4
AM...HOWEVER...THEY ARE EXPECTED TO DEVELOP THROUGH DAYBREAK.
PARTLY CLOUDY SHOULD HANDLE MOST OF TODAY.
OTHER THEN THIS NOT EXPECTING ANY SHOWERS AND THUNDERSTORMS TO
DEVELOP TODAY...THEY SHOULD HOLD OFF UNTIL AFTER 6 PM. NOT
EXPECTING MUCH OF A LAKE BREEZE AS THE GRADIENT WILL BE TOO
STRONG. ERIE MAY GET A LAKE BREEZE FOR A TIME THIS AFTERNOON. WENT
ON THE WARMER SIDE OF GUIDANCE FOR HIGHS BECAUSE OF AN INCREASING
SOUTHWEST FLOW AND WARMER AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER LOW AND SURFACE LOW NOW OVER THE NORTHERN PLAINS WILL
MOVE SLOWLY EAST AND BE OVER THE FORECAST AREA THURSDAY AND
THURSDAY NIGHT. IN THE MEANTIME THE CHALLENGE IS FIGURING OUT THE
SHOWER AND THUNDERSTORM CHANCES.
FOR TONIGHT THE UPPER RIDGE MOVES EAST AND WITH SOME MOISTURE AND A
WEAK IMPULSE MOVING THROUGH KEPT CHANCE POPS MAINLY OVER THE
NORTHERN PORTION OF THE FORECAST AREA. THE RADAR FORECAST FROM THE
4KM WRF NMM 00Z MODEL SEEMS REASONABLE WITH SOME THUNDERSTORMS
BRUSHING THE NORTHERN PORTION OF THE FORECAST AREA.
FOR TUESDAY CHANCE POPS MOST AREAS BUT DID CONTINUE LIKELY POPS
EXTREME NORTHWEST OHIO. ON THE EDGE ABOUT THAT BASED ON THE LACK
OF MOISTURE ALOFT. THE AIRMASS IS UNSTABLE. FOR TUESDAY NIGHT
AGAIN...CHANCE POPS AS THE AIRMASS IS BECOMING MORE MOIST AND
CONTINUED UNSTABLE. FOR WEDNESDAY INTO THURSDAY WITH THE FRONT
GETTING CLOSE WEDNESDAY AND THEN SAGGING THROUGH ON THURSDAY
LIKELY POPS AT TIMES LOOKS VERY GOOD. AS WE GET CLOSER WE WILL BE
ABLE TO PUT MORE RESOLUTION INTO THE FORECAST.
USED A BLEND OF GUIDANCE AND THE PREVIOUS FORECAST FOR THE HIGHS AND
LOWS. THE HIGHS TUESDAY AND WEDNESDAY ARE TRICKY IF WE GET TOO MUCH
CONVECTION AND CLOUDS THIS WILL HAVE A TREMENDOUS IMPACT ON THE
TEMPERATURES.
RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN INCH FOR THIS
WEEK...EXCEPT LOCALLY HIGHER AMOUNTS IN SOME THUNDERSTORMS.
THE AIRMASS FOR TONIGHT WILL BE SOMEWHAT DRY ALOFT AND THIS WILL
LEAD TO POSSIBLE SIGNIFICANT DOWNDRAFTS AS PER THE DELTA THETA E...WILL
MENTION THAT IN THE HAZARDOUS WEATHER OUTLOOK. WILL ALSO MENTION
RISK OF SEVERE TUESDAY THROUGH WEDNESDAY NIGHT ESPECIALLY.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LITTLE CHANGE IN THE EXTENDED. BOTH GFS AND ECMWF MOVE HIGH
PRESSURE OVER THE AREA FRIDAY...WHICH LINGERS THROUGH THE WEEKEND.
EXTENDED LOOKS DRY WITH MORE SEASONAL TEMPS THROUGH THE WEEKEND.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
WITH DEW POINTS CREEPING INTO THE 60S DO EXPECT MORE MVFR BR THIS
MORNING...BUT WIND SHOULD HELP IT FROM BEING TOO WIDESPREAD. SHORT
TERM MODELS NOT IN AGREEMENT ON THE TSRA IN ILLINOIS...LATEST HRR
MOVE TSRA INTO NW OH BY 12Z. FOR NOW WILL ONLY ADD VCTS TO TOL AND
FDY SINCE CONFIDENCE IS LOW AT THIS TIME.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS MONDAY
EVENING THROUGH THURSDAY.
&&
.MARINE...
PREDOMINATELY A SOUTH TO SOUTHEAST FLOW TODAY ALTHOUGH COULD SEE A
WEAK LAKE BREEZE EAST HALF FOR A FEW HOURS. EXPECT SOUTHWEST FLOW
TO DEVELOP TOMORROW AHEAD OF NEXT SYSTEM. MODELS IN GOOD AGREEMENT
PUSHING THE NEXT FRONT THROUGH ON THURSDAY. WITH NORTH TO NORTHEAST
FLOW DEVELOPING BEHIND THE SYSTEM WILL APPROACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
357 AM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER RIDGE ACROSS THE AREA TODAY WILL MOVE EAST TONIGHT. A
WEAK WARM FRONT WILL MOVE ACROSS THE REGION TODAY. AN AREA OF LOW
PRESSURE OVER THE NORTHERN PLAINS WILL SLOWLY PROGRESS EASTWARD
ACROSS THE GREAT LAKES REGION THROUGH MID WEEK. THE AIRMASS WILL
BECOME INCREASINGLY MOIST AND UNSTABLE AS THIS FEATURE APPROACHES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY IS A TOUGH FORECAST. THE HRRR AND RUC/RAP MODELS HAVE BEEN
FORECASTING A NARROW BAND OF SHOWERS/THUNDERSTORMS TO DEVELOP OVER
EASTERN INDIANA EARLY THIS MORNING AND THEN MOVE EAST. AT 3 AM EDT
THE ILN 88D WAS INDICATING A FINE LINE OVER SE INDIANA. AS EACH HOUR
HAS GONE ON THE MODELS ARE DELAYING THE DEVELOPMENT AND INTENSITY OF
THE PRECIPITATION. NOW THEY DON`T HAVE ANY PRECIPITATION DEVELOPING
ON THIS LINE UNTIL AROUND 8 OR 9 AM MAINLY FROM CLE SOUTH.
SOME OF THE RADAR FORECAST OUTPUT FROM SPC STORM-SCALE
ENSEMBLE OF OPPORTUNITY MODELS ARE ALL OVER THE PLACE FOR
TODAY...SOME WITH NO SHOWER OR THUNDERSTORM DEVELOPMENT IN THE
FORECAST AREA AND SOME WITH A LITTLE DEVELOPMENT. THE 4KM WRF NMM
MODEL HAS SOME ISOLATED SHOWERS DEVELOPING. CONFIDENCE IS LOW IN
THIS BECAUSE OF SO MUCH RIDGING ALOFT...BUT WILL FORECAST A CHANCE
OF SPRINKLES MAINLY THIS AM AS THIS LINE MOVES THROUGH. WILL
MONITOR THIS AND UPDATE AS NEEDED.
ANY FOG THAT DEVELOPS THROUGH DAYBREAK SHOULD NOT BE SIGNIFICANT
ENOUGH TO BE MENTIONED IN THE ZONES/GRIDS.
OTHER THEN THIS NOT EXPECTING ANY SHOWERS AND THUNDERSTORMS TO
DEVELOP TODAY...THEY SHOULD HOLD OFF UNTIL AFTER 6 PM. NOT EXPECTING
MUCH OF A LAKE BREEZE AS THE GRADIENT WILL BE TOO STRONG. ERIE MAY
GET A LAKE BREEZE FOR A TIME THIS AFTERNOON. WENT ON THE WARMER SIDE OF
GUIDANCE FOR HIGHS BECAUSE OF AN INCREASING SOUTHWEST FLOW AND
WARMER AIR ALOFT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER LOW AND SURFACE LOW NOW OVER THE NORTHERN PLAINS WILL
MOVE SLOWLY EAST AND BE OVER THE FORECAST AREA THURSDAY AND
THURSDAY NIGHT. IN THE MEANTIME THE CHALLENGE IS FIGURING OUT THE
SHOWER AND THUNDERSTORM CHANCES.
FOR TONIGHT THE UPPER RIDGE MOVES EAST AND WITH SOME MOISTURE AND A
WEAK IMPULSE MOVING THROUGH KEPT CHANCE POPS MAINLY OVER THE
NORTHERN PORTION OF THE FORECAST AREA. THE RADAR FORECAST FROM THE
4KM WRF NMM 00Z MODEL SEEMS REASONABLE WITH SOME THUNDERSTORMS
BRUSHING THE NORTHERN PORTION OF THE FORECAST AREA.
FOR TUESDAY CHANCE POPS MOST AREAS BUT DID CONTINUE LIKELY POPS
EXTREME NORTHWEST OHIO. ON THE EDGE ABOUT THAT BASED ON THE LACK
OF MOISTURE ALOFT. THE AIRMASS IS UNSTABLE. FOR TUESDAY NIGHT
AGAIN...CHANCE POPS AS THE AIRMASS IS BECOMING MORE MOIST AND
CONTINUED UNSTABLE. FOR WEDNESDAY INTO THURSDAY WITH THE FRONT
GETTING CLOSE WEDNESDAY AND THEN SAGGING THROUGH ON THURSDAY
LIKELY POPS AT TIMES LOOKS VERY GOOD. AS WE GET CLOSER WE WILL BE
ABLE TO PUT MORE RESOLUTION INTO THE FORECAST.
USED A BLEND OF GUIDANCE AND THE PREVIOUS FORECAST FOR THE HIGHS AND
LOWS. THE HIGHS TUESDAY AND WEDNESDAY ARE TRICKY IF WE GET TOO MUCH
CONVECTION AND CLOUDS THIS WILL HAVE A TREMENDOUS IMPACT ON THE
TEMPERATURES.
RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN INCH FOR THIS
WEEK...EXCEPT LOCALLY HIGHER AMOUNTS IN SOME THUNDERSTORMS.
THE AIRMASS FOR TONIGHT WILL BE SOMEWHAT DRY ALOFT AND THIS WILL
LEAD TO POSSIBLE SIGNIFICANT DOWNDRAFTS AS PER THE DELTA THETA E...WILL
MENTION THAT IN THE HAZARDOUS WEATHER OUTLOOK. WILL ALSO MENTION
RISK OF SEVERE TUESDAY THROUGH WEDNESDAY NIGHT ESPECIALLY.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LITTLE CHANGE IN THE EXTENDED. BOTH GFS AND ECMWF MOVE HIGH
PRESSURE OVER THE AREA FRIDAY...WHICH LINGERS THROUGH THE WEEKEND.
EXTENDED LOOKS DRY WITH MORE SEASONAL TEMPS THROUGH THE WEEKEND.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
WITH DEW POINTS CREEPING INTO THE 60S DO EXPECT MORE MVFR BR THIS
MORNING...BUT WIND SHOULD HELP IT FROM BEING TOO WIDESPREAD. SHORT
TERM MODELS NOT IN AGREEMENT ON THE TSRA IN ILLINOIS...LATEST HRR
MOVE TSRA INTO NW OH BY 12Z. FOR NOW WILL ONLY ADD VCTS TO TOL AND
FDY SINCE CONFIDENCE IS LOW AT THIS TIME.
.OUTLOOK...NON VFR PROBABLE IN SHOWERS/THUNDERSTORMS MONDAY
EVENING THROUGH THURSDAY.
&&
.MARINE...
PREDOMINATELY A SOUTH TO SOUTHEAST FLOW TODAY ALTHOUGH COULD SEE A
WEAK LAKE BREEZE EAST HALF FOR A FEW HOURS. EXPECT SOUTHWEST FLOW
TO DEVELOP TOMORROW AHEAD OF NEXT SYSTEM. MODELS IN GOOD AGREEMENT
PUSHING THE NEXT FRONT THROUGH ON THURSDAY. WITH NORTH TO NORTHEAST
FLOW DEVELOPING BEHIND THE SYSTEM WILL APPROACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS TULSA OK
917 PM CDT TUE MAY 21 2013
...UPDATE...
.DISCUSSION...
PRECIPITATION HAS MOVED EAST OUT OF THE ENTIRE FORECAST AREA
QUICKLY THIS EVENING. SKIES ARE CLEARING FROM THE WEST AS DRY AIR
PUSHES IN BEHIND THE DEPARTING UPPER SYSTEM. HAVE REMOVED POPS FOR
ALL BUT THE EASTERN MOST SLIVER OF THE CWA. HAVE ALSO CLEARED
SKIES A LITTLE FASTER OVERNIGHT. HAVE LEFT FORECAST MINIMUM
TEMPERATURES AS THEY WERE. UPDATED PRODUCTS HAVE ALL BEEN SENT.
&&
.PREV DISCUSSION... /ISSUED 648 PM CDT TUE MAY 21 2013/
DISCUSSION...
THE 00Z TAF DISCUSSION IS INCLUDED BELOW.
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
RAIN/STORMS ARE MOVING OUT...WITH SKIES CLEARING THIS EVENING. DUE
TO THE RECENT RAINS AND WET GROUND...SOME PATCHY FOG WILL LIKELY
DEVELOP. THINK THE FOG WILL BE MOST PROMINENT OVER SOUTHEAST OK
WHERE THE HEAVIEST RAINS FELL SO I HAVE BROUGHT KMLC DOWN TO IFR
VSBY. THE HYDROLAPSE BECOMES UNFAVORABLE FOR WIDESPREAD DENSE FOG
TONIGHT AS THE BOUNDARY LAYER DRIES OUT AFTER MIDNIGHT. SO FOR
NOW STAYED CONSERVATIVE ON VSBYS AT THE OTHER SITES.
LACY
PREV DISCUSSION... /ISSUED 312 PM CDT TUE MAY 21 2013/
DISCUSSION...
LINEAR MCS THAT HAS FORMED AHEAD OF COMPACT UPPER SYSTEM SURGING
ACROSS OK/TX IS CURRENTLY MOVING ACROSS PORTIONS OF SERN OK. THE
LINE HAS BEEN STRONG/MARGINALLY SEVERE SO FAR...AND STILL COULD SEE
SOME 60+ MPH WIND GUSTS OVER THE NEXT FEW HOURS. HRRR HAS SHOWN A
VERY GOOD HANDLE ON THE COMPLEX...WITH THE LEADING EDGE EXITING OUR
FORECAST AREA AROUND 22Z-23Z. CURRENT FLASH FLOOD WATCH IS SET TO
EXPIRE AT 00Z...ALTHOUGH MAY EXTEND IT A FEW MORE HOURS. WILL TAKE A
LAST LOOK AT RADAR BEFORE FINAL DECISION. OTHERWISE...PARTIALLY
CLEARING SKIES ALONG WITH DRIER LOW-LEVEL AIR WILL ALLOW TEMPS TO
FALL INTO THE 50S FOR MUCH OF THE AREA.
WEAK SURFACE BOUNDARY MAY BE PRESENT ACROSS THE AREA ON
WEDNESDAY...ALTHOUGH ATMOSPHERE SHOULD BE TOO DRY AND WORKED OVER TO
SUPPORT PRECIPITATION.
UPPER PATTERN WILL BECOME INCREASINGLY AMPLIFIED BY MID-TO-LATE
WEEK...WITH RIDGING THROUGH THE PLAINS SANDWICHED BY DEEP UPPER
SYSTEMS ACROSS THE PAC NW AND THE EAST COAST. MODELS SUGGEST THAT
SEVERAL WEAK WAVES WILL MOVE INTO THE MEAN RIDGE POSITION...WITH AT
LEAST SOME LOW POPS WARRANTED ACROSS WRN SECTIONS IN THE VERY
WARM/MOIST AIRMASS.
UPPER RIDGE SHOULD FLATTEN SOME ACROSS THE SRN/CENTRL PLAINS GOING
INTO THE WEEKEND. WITH THE FORECAST AREA ALONG THE SRN EDGE OF THE
STRONGER UPPER FLOW...SHOULD SEE PERIODIC SHOWER/THUNDERSTORM
EPISODES...ESPECIALLY ACROSS NE OK/NW AR. TOUGH TO PINPOINT WHICH
DAY WILL HAVE THE BEST CHANCES...SO HAVE MAINTAINED GENERAL CHANCE
POPS FOR ABOUT THE NRN HALF OF THE AREA FOR THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...06
AREA FORECAST DISCUSSION
NWS TULSA OK
648 PM CDT TUE MAY 21 2013
.DISCUSSION...
THE 00Z TAF DISCUSSION IS INCLUDED BELOW.
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
RAIN/STORMS ARE MOVING OUT...WITH SKIES CLEARING THIS EVENING. DUE
TO THE RECENT RAINS AND WET GROUND...SOME PATCHY FOG WILL LIKELY
DEVELOP. THINK THE FOG WILL BE MOST PROMINENT OVER SOUTHEAST OK
WHERE THE HEAVIEST RAINS FELL SO I HAVE BROUGHT KMLC DOWN TO IFR
VSBY. THE HYDROLAPSE BECOMES UNFAVORABLE FOR WIDESPREAD DENSE FOG
TONIGHT AS THE BOUNDARY LAYER DRIES OUT AFTER MIDNIGHT. SO FOR
NOW STAYED CONSERVATIVE ON VSBYS AT THE OTHER SITES.
LACY
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT TUE MAY 21 2013/
DISCUSSION...
LINEAR MCS THAT HAS FORMED AHEAD OF COMPACT UPPER SYSTEM SURGING
ACROSS OK/TX IS CURRENTLY MOVING ACROSS PORTIONS OF SERN OK. THE
LINE HAS BEEN STRONG/MARGINALLY SEVERE SO FAR...AND STILL COULD SEE
SOME 60+ MPH WIND GUSTS OVER THE NEXT FEW HOURS. HRRR HAS SHOWN A
VERY GOOD HANDLE ON THE COMPLEX...WITH THE LEADING EDGE EXITING OUR
FORECAST AREA AROUND 22Z-23Z. CURRENT FLASH FLOOD WATCH IS SET TO
EXPIRE AT 00Z...ALTHOUGH MAY EXTEND IT A FEW MORE HOURS. WILL TAKE A
LAST LOOK AT RADAR BEFORE FINAL DECISION. OTHERWISE...PARTIALLY
CLEARING SKIES ALONG WITH DRIER LOW-LEVEL AIR WILL ALLOW TEMPS TO
FALL INTO THE 50S FOR MUCH OF THE AREA.
WEAK SURFACE BOUNDARY MAY BE PRESENT ACROSS THE AREA ON
WEDNESDAY...ALTHOUGH ATMOSPHERE SHOULD BE TOO DRY AND WORKED OVER TO
SUPPORT PRECIPITATION.
UPPER PATTERN WILL BECOME INCREASINGLY AMPLIFIED BY MID-TO-LATE
WEEK...WITH RIDGING THROUGH THE PLAINS SANDWICHED BY DEEP UPPER
SYSTEMS ACROSS THE PAC NW AND THE EAST COAST. MODELS SUGGEST THAT
SEVERAL WEAK WAVES WILL MOVE INTO THE MEAN RIDGE POSITION...WITH AT
LEAST SOME LOW POPS WARRANTED ACROSS WRN SECTIONS IN THE VERY
WARM/MOIST AIRMASS.
UPPER RIDGE SHOULD FLATTEN SOME ACROSS THE SRN/CENTRL PLAINS GOING
INTO THE WEEKEND. WITH THE FORECAST AREA ALONG THE SRN EDGE OF THE
STRONGER UPPER FLOW...SHOULD SEE PERIODIC SHOWER/THUNDERSTORM
EPISODES...ESPECIALLY ACROSS NE OK/NW AR. TOUGH TO PINPOINT WHICH
DAY WILL HAVE THE BEST CHANCES...SO HAVE MAINTAINED GENERAL CHANCE
POPS FOR ABOUT THE NRN HALF OF THE AREA FOR THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 55 81 58 78 / 10 0 10 20
FSM 58 83 62 81 / 60 10 10 10
MLC 55 83 61 84 / 20 0 10 20
BVO 52 81 54 77 / 10 0 10 20
FYV 54 79 55 76 / 70 10 10 10
BYV 56 79 55 77 / 70 10 10 10
MKO 55 82 60 79 / 20 10 10 20
MIO 54 78 56 78 / 20 10 10 10
F10 55 82 61 79 / 10 0 10 20
HHW 60 85 64 85 / 20 0 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH UNTIL 7 PM TUESDAY FOR OKZ049-OKZ053-OKZ068-
OKZ069-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076.
AR...FLASH FLOOD WATCH UNTIL 7 PM TUESDAY FOR ARZ001-ARZ002-ARZ010-
ARZ011-ARZ019-ARZ020-ARZ029.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1142 PM EDT TUE MAY 21 2013
.SYNOPSIS...
A WARM AND HUMID SUMMERTIME AIR MASS WILL CONTINUE TO BRING WELL
ABOVE NORMAL TEMPERATURES TO CENTRAL PENNSYLVANIA THROUGH
WEDNESDAY. A COLD FRONT WILL CROSS THE REGION ON THURSDAY. A
SECOND FRONT WILL PUSH THROUGH ON FRIDAY AND USHER IN HIGH
PRESSURE FROM CENTRAL CANADA INTO THE NORTHEAST AND MID-ATLANTIC
STATES. THIS HIGH WILL BRING COOLER AND DRIER AIR TO THE AREA FOR
MEMORIAL DAY WEEKEND THAT COULD LAST RIGHT THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
STORMS ONLY NOW TOUCHING NRN WARREN COUNTY AS BEST MOISTURE
CONVERGENCE STAYS ALONG THE NRN BORDER. TEMPS HAVE DROPPED OFF AT
THE SFC...BUT INSTABILITY STILL HIGH ALOFT. ISOLATED/SCT SHOWERS
AND STORMS MOVING THROUGH PIT AND CRW RIGHT NOW ARE ON TRACK TO
MOVE INTO THE SWRN COS BY MIDNIGHT AND COULD LAST INTO THE MIDDLE
OF THE NIGHT IF THEY HOLD TOGETHER. RUC HOLDS ONTO THE CELLS FOR
ANOTHER HOUR OR TWO...BUT THEN DISSIPATES THEM. THIS SEEMS
PLAUSIBLE SINCE THEY ARE NOT LOOKING VERY HEALTHY RIGHT NOW. THE
CLUSTER FROM WV SEEMS TO HAVE MORE ORGANIZATION AND WILL KEEP ON
WITH LOW CHC POPS FOR THE SW INTO THE WEE HOURS. THE RUC AND HRRR
ARE AT ODDS WITH EACH OTHER WRT THE CONVECTION ALONG THE NY
BORDER. RUC CONTINUES IT THROUGH MUCH OF THE NIGHT...BUT HRRR
BREAKS IT APART. WILL ALSO HOLD THE LINE WITH CHC POPS FOR THE NRN
TIER OF COUNTIES SEEING NO PREPONDERANCE OF GUIDANCE THAT IS
AGAINST SOME MEASURE OF ELEVATED INSTABILITY AND POTENTIAL FOR
CONVECTION THERE. WILL KEEP MENTIONS OF PATCHY FOG AS WELL..WITH
MAINLY CLEAR SKIES RIGHT NOW AND HIGH DEWPOINTS. CLOUDS FROM
UPSTREAM WILL PROBABLY LEVEL TEMPS OFF IN A FEW HOURS...BUT FOG
MAY YET CREEP INTO THE VALLEYS.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
A S/W MOVG EWD ACRS THE UPPER MS VLY INVOF IA WILL PHASE WITH A
CANADIAN UPPER LOW/TROUGH DROPPING SWD ACRS HUDSON/JAMES BAY DURING
THE DAY WEDNESDAY...REACHING THE MIDWEST BY F48. AT THE SFC...A
COLD FRONT PUSHING EWD THRU THE OH VLY WILL BE THE MAIN FOCUS FOR
TSTM DEVELOPMENT/SVR POTENTIAL THIS PERIOD.
AM CLOUDS WITH SOME SPOTTY SHOWERS AND AREAS OF 1-2SM FIG WILL
COMBINE WITH WEAK RIDGING WITHIN THE PREDOMINANT SWRLY FLOW
ALOFT...TO LIMIT DIURNAL HEATING TO SOME EXTENT ACRS THE DAY 2 SPC
SLGT RISK AREA - WHICH COVERS NEARLY ALL OF THE CWA WITH THE
EXCEPTION OF THE FAR SERN ZONES. ALTHOUGH LOW TO MID LEVEL WINDS
WILL BE STRONGEST ACROSS THE NW HALF OF PENN...LATEST SREF AND SHORT
RANGE MODEL GUIDANCE PAINTS THE GREATEST PROBABILITY FOR CAPE
GREATER THAN 1200 J/KG ACROSS THE LOWER SUSQ VALLEY LATE WEDNESDAY
AFTERNOON.
DESPITE THE TEMPERED DESTABILIZATION...EXPECT AN AFTN INCREASE IN
TSTM COVERAGE /WITH LOWER CLOUD BASES COMPARED TO TUESDAY`S/ ALONG
WITH SOME PICK-UP IN INTENSITY AS BELT OF STRONGER FLOW ALOFT SHIFTS
EWD AHEAD OF THE MID-UPPER TROUGH. BANDS OF TSTMS CAPABLE OF
PRODUCING DMGG WNDS/MARGINAL HAIL WILL BE POSSIBLE AND THUS WILL
CONTINUE TO HIGHLIGHT AN ELEVATED SVR WX THREAT IN THE HWO FOR
WEDNESDAY. BETTER FORCING PORTENDS HIGHER POPS RANGING FROM THE
MED-HIGH CHC RANGE IN THE SE TO LOW LKLYS IN THE NW. SHOWERS/TSTMS
MAY PERSIST AFTER DARK INTO WED NGT.
MAX TEMPS WILL LIKELY BE 3-5F LOWER THAN TUESDAY...BUT STILL AROUND
12F ABOVE NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE UPPER RIDGE WILL BREAK DOWN AS A TROUGH DEEPENS INTO THE GREAT
LAKES REGION BY THURSDAY AFTERNOON. THIS WILL CORRESPOND WITH A
FRONT MOVING THROUGH THE NORTHEAST THURSDAY. TIMING FOR THIS FRONT
IS STILL VARYING BUT CURRENT EC BRINGS THE FRONT THROUGH MIDDAY
THURSDAY. COUPLE THIS FRONT WITH DAYTIME HEATING AND STRONG
SOUTHWEST FLOW...THURSDAY COULD BE THE BEST DAY FOR DAYTIME
CONVECTION THIS WEEK. BOTH THE OPERATIONAL GFS AND THE ECMWF CONTINUE
TO OUTPUT THE POSSIBILITY OF A LOW LEVEL JET THURSDAY
AFTERNOON...WHICH WITH 35-40KTS OF DEEP-LAYER SHEAR WILL ONLY
INCREASE PROBABILITIES FOR PRECIPITATION THURSDAY AFTERNOON. THIS
EASTERN NORTH AMERICA TROUGH AXIS EXTENDING FROM JAMES BAY SWD
THRU THE GRT LKS/MID- SOUTH TO THE CENTRAL GULF COAST WILL PUSH
SLOWLY EWD AND SHOULD REACH THE EAST COAST BY 00Z SAT. THIS WILL
ALLOW FOR PERSISTENT INSTABILITY OVER THE AREA THROUGH THE END OF
THE WEEK...WITH COLD NORTHWESTERLY FLOW BEHIND THE FRONT. THE
GUIDANCE IS SHOWING SOME NOTABLE DIFFS WITH THE H5 SYSTEM. THE
NAM/GFS/GEFS ARE SLOWER AND SHARPER WITH TROUGH AS IT CROSSES THE
OH VLY INTO THE MID- ATLC. THE 00Z GFS EVEN CLOSES OFF THE H5 LOW
OVER NRN VA FRI EVE. THE LAST TWO RUNS OF THE CMC HAVE BEEN TRYING
TO GENERATE A TROPICAL CYCLONE- LIKE SYSTEM NEAR THE OUTER BANKS.
THE KNOWN SLOW/TROPICAL BIASES OF THE NAM/CMC AND STRONG/CLOSED
SOLN OF THE GFS LEADS TO A UKMET/ECMWF PREFERRED SOLN WHICH FAVORS
MORE EWD PROGRESSION WITH THE TROUGH AND ITS ASSOCD COLD FRONT.
BEHIND THE DEPARTING COLD FRONT...A STG AND LARGE ANTICYCLONE
SHOULD DOMINATE PATTERN IN THE FRI-MON TIMEFRAME...BUILDING SEWD
FROM NUNAVUT CANADA ACROSS THE GRT LKS INTO THE NORTHEAST. AN
UNSEASONABLY COLD/DRY AIRMASS WILL ACCOMPANY THE HIGH RESULTING IN
BELOW NORMAL TEMPS FOR MEMORIAL DAY WEEKEND. ECENS MOS DATA SHOWS
TEMPS ON FRI/SAT STRUGGLING TO CRACK THE 60F MARK LOCALLY...WITH
SEVERAL OPPORTUNITIES FOR A LATE-SEASON FROST OVER THE NRN MTNS
SAT/SUN/MON MORNINGS. HOWEVER CURRENT LOW TEMPS REMAIN ABOVE 40
FOR MOST OF THE REGION WITH THE EXCEPTION BEING ALONG THE NEW YORK
BORDER. WINDS SHOULD REMAIN GUSTY SATURDAY MORNING. THE BETTER
CHANCE FOR FROST WILL BE SUNDAY MORNING...TEMPERATURES WILL BE
SLIGHTLY WARMER BUT THE WINDS SHOULD BE LIGHT TO CALM. THERE
SHOULD BE A MODERATION INTO THE MIDDLE OF NEXT WEEK WITH TEMPS
GETTING BACK TO NEAR NORMAL AROUND 5/28.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
NOT A LOT OF CHANGE. STILL AN ISOLATED STORM POSSIBLE NEAR
THE NY BORDER OVERNIGHT. ALSO MAYBE A BRIEF SHOWER CLOSE
TO JST...LEFT OUT THE FCST FOR NOW.
EARLIER DISCUSSION BELOW.
MAIN FRONT AND ACTION ACROSS NY STATE...TOOK MENTION OF SHOWERS
AND STORMS OUT OF ALL SITES BUT BFD. LEFT VCSH IN BFD UNTIL 03Z.
SOME FOG LATER...BASED MAINLY ON WHAT WENT ON LAST NIGHT.
NOT SEEING MUCH DIFFERENCE FOR WED...VERY SIMILAR TO TODAY...
WILL BE IN THE WARM SECTOR...WITH NOT MUCH GOING ON.
MORE IN THE WAY OF WIDESPREAD SHOWERS AND STORMS LATER THU
INTO THU NIGHT. COULD BY BUSY ACROSS THE FAR SE THU NIGHT...
IF A WAVE FORMS ON THE FRONT.
COOLER AND BREEZY FOR FRIDAY INTO SUNDAY...AS A STRONG COLD
FRONT DROPS SE OF PA.
HO
.OUTLOOK...
THU...SCT THUNDERSTORM IMPACTS POSSIBLE...MAINLY IN THE PM.
FRI-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...LAMBERT/STEINBUGL
LONG TERM...CERU/STEINBUGL
AVIATION...LAMBERT/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1007 PM EDT TUE MAY 21 2013
.SYNOPSIS...
A WARM AND HUMID SUMMERTIME AIR MASS WILL CONTINUE TO BRING WELL
ABOVE NORMAL TEMPERATURES TO CENTRAL PENNSYLVANIA THROUGH
WEDNESDAY. A COLD FRONT WILL CROSS THE REGION ON THURSDAY. A
SECOND FRONT WILL PUSH THROUGH ON FRIDAY AND USHER IN HIGH
PRESSURE FROM CENTRAL CANADA INTO THE NORTHEAST AND MID-ATLANTIC
STATES. THIS HIGH WILL BRING COOLER AND DRIER AIR TO THE AREA FOR
MEMORIAL DAY WEEKEND THAT COULD LAST RIGHT THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
STORMS ONLY NOW TOUCHING NRN WARREN COUNTY AS BEST MOISTURE
CONVERGENCE STAYS ALONG THE NRN BORDER. TEMPS HAVE DROPPED OFF AT
THE SFC...BUT INSTABILITY STILL HIGH ALOFT. ISOLATED/SCT SHOWERS
AND STORMS MOVING THROUGH PIT AND CRW RIGHT NOW ARE ON TRACK TO
MOVE INTO THE SWRN COS BY MIDNIGHT AND COULD LAST INTO THE MIDDLE
OF THE NIGHT IF THEY HOLD TOGETHER. RUC HOLDS ONTO THE CELLS FOR
ANOTHER HOUR OR TWO...BUT THEN DISSIPATES THEM. THIS SEEMS
PLAUSIBLE SINCE THEY ARE NOT LOOKING VERY HEALTHY RIGHT NOW. THE
CLUSTER FROM WV SEEMS TO HAVE MORE ORGANIZATION AND WILL KEEP ON
WITH LOW CHC POPS FOR THE SW INTO THE WEE HOURS. THE RUC AND HRRR
ARE AT ODDS WITH EACH OTHER WRT THE CONVECTION ALONG THE NY
BORDER. RUC CONTINUES IT THROUGH MUCH OF THE NIGHT...BUT HRRR
BREAKS IT APART. WILL ALSO HOLD THE LINE WITH CHC POPS FOR THE NRN
TIER OF COUNTIES SEEING NO PREPONDERANCE OF GUIDANCE THAT IS
AGAINST SOME MEASURE OF ELEVATED INSTABILITY AND POTENTIAL FOR
CONVECTION THERE. WILL KEEP MENTIONS OF PATCHY FOG AS WELL..WITH
MAINLY CLEAR SKIES RIGHT NOW AND HIGH DEWPOINTS. CLOUDS FROM
UPSTREAM WILL PROBABLY LEVEL TEMPS OFF IN A FEW HOURS...BUT FOG
MAY YET CREEP INTO THE VALLEYS.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
A S/W MOVG EWD ACRS THE UPPER MS VLY INVOF IA WILL PHASE WITH A
CANADIAN UPPER LOW/TROUGH DROPPING SWD ACRS HUDSON/JAMES BAY DURING
THE DAY WEDNESDAY...REACHING THE MIDWEST BY F48. AT THE SFC...A
COLD FRONT PUSHING EWD THRU THE OH VLY WILL BE THE MAIN FOCUS FOR
TSTM DEVELOPMENT/SVR POTENTIAL THIS PERIOD.
AM CLOUDS WITH SOME SPOTTY SHOWERS AND AREAS OF 1-2SM FIG WILL
COMBINE WITH WEAK RIDGING WITHIN THE PREDOMINANT SWRLY FLOW
ALOFT...TO LIMIT DIURNAL HEATING TO SOME EXTENT ACRS THE DAY 2 SPC
SLGT RISK AREA - WHICH COVERS NEARLY ALL OF THE CWA WITH THE
EXCEPTION OF THE FAR SERN ZONES. ALTHOUGH LOW TO MID LEVEL WINDS
WILL BE STRONGEST ACROSS THE NW HALF OF PENN...LATEST SREF AND SHORT
RANGE MODEL GUIDANCE PAINTS THE GREATEST PROBABILITY FOR CAPE
GREATER THAN 1200 J/KG ACROSS THE LOWER SUSQ VALLEY LATE WEDNESDAY
AFTERNOON.
DESPITE THE TEMPERED DESTABILIZATION...EXPECT AN AFTN INCREASE IN
TSTM COVERAGE /WITH LOWER CLOUD BASES COMPARED TO TUESDAY`S/ ALONG
WITH SOME PICK-UP IN INTENSITY AS BELT OF STRONGER FLOW ALOFT SHIFTS
EWD AHEAD OF THE MID-UPPER TROUGH. BANDS OF TSTMS CAPABLE OF
PRODUCING DMGG WNDS/MARGINAL HAIL WILL BE POSSIBLE AND THUS WILL
CONTINUE TO HIGHLIGHT AN ELEVATED SVR WX THREAT IN THE HWO FOR
WEDNESDAY. BETTER FORCING PORTENDS HIGHER POPS RANGING FROM THE
MED-HIGH CHC RANGE IN THE SE TO LOW LKLYS IN THE NW. SHOWERS/TSTMS
MAY PERSIST AFTER DARK INTO WED NGT.
MAX TEMPS WILL LIKELY BE 3-5F LOWER THAN TUESDAY...BUT STILL AROUND
12F ABOVE NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE UPPER RIDGE WILL BREAK DOWN AS A TROUGH DEEPENS INTO THE GREAT
LAKES REGION BY THURSDAY AFTERNOON. THIS WILL CORRESPOND WITH A
FRONT MOVING THROUGH THE NORTHEAST THURSDAY. TIMING FOR THIS FRONT
IS STILL VARYING BUT CURRENT EC BRINGS THE FRONT THROUGH MIDDAY
THURSDAY. COUPLE THIS FRONT WITH DAYTIME HEATING AND STRONG
SOUTHWEST FLOW...THURSDAY COULD BE THE BEST DAY FOR DAYTIME
CONVECTION THIS WEEK. BOTH THE OPERATIONAL GFS AND THE ECMWF CONTINUE
TO OUTPUT THE POSSIBILITY OF A LOW LEVEL JET THURSDAY
AFTERNOON...WHICH WITH 35-40KTS OF DEEP-LAYER SHEAR WILL ONLY
INCREASE PROBABILITIES FOR PRECIPITATION THURSDAY AFTERNOON. THIS
EASTERN NORTH AMERICA TROUGH AXIS EXTENDING FROM JAMES BAY SWD
THRU THE GRT LKS/MID- SOUTH TO THE CENTRAL GULF COAST WILL PUSH
SLOWLY EWD AND SHOULD REACH THE EAST COAST BY 00Z SAT. THIS WILL
ALLOW FOR PERSISTENT INSTABILITY OVER THE AREA THROUGH THE END OF
THE WEEK...WITH COLD NORTHWESTERLY FLOW BEHIND THE FRONT. THE
GUIDANCE IS SHOWING SOME NOTABLE DIFFS WITH THE H5 SYSTEM. THE
NAM/GFS/GEFS ARE SLOWER AND SHARPER WITH TROUGH AS IT CROSSES THE
OH VLY INTO THE MID- ATLC. THE 00Z GFS EVEN CLOSES OFF THE H5 LOW
OVER NRN VA FRI EVE. THE LAST TWO RUNS OF THE CMC HAVE BEEN TRYING
TO GENERATE A TROPICAL CYCLONE- LIKE SYSTEM NEAR THE OUTER BANKS.
THE KNOWN SLOW/TROPICAL BIASES OF THE NAM/CMC AND STRONG/CLOSED
SOLN OF THE GFS LEADS TO A UKMET/ECMWF PREFERRED SOLN WHICH FAVORS
MORE EWD PROGRESSION WITH THE TROUGH AND ITS ASSOCD COLD FRONT.
BEHIND THE DEPARTING COLD FRONT...A STG AND LARGE ANTICYCLONE
SHOULD DOMINATE PATTERN IN THE FRI-MON TIMEFRAME...BUILDING SEWD
FROM NUNAVUT CANADA ACROSS THE GRT LKS INTO THE NORTHEAST. AN
UNSEASONABLY COLD/DRY AIRMASS WILL ACCOMPANY THE HIGH RESULTING IN
BELOW NORMAL TEMPS FOR MEMORIAL DAY WEEKEND. ECENS MOS DATA SHOWS
TEMPS ON FRI/SAT STRUGGLING TO CRACK THE 60F MARK LOCALLY...WITH
SEVERAL OPPORTUNITIES FOR A LATE-SEASON FROST OVER THE NRN MTNS
SAT/SUN/MON MORNINGS. HOWEVER CURRENT LOW TEMPS REMAIN ABOVE 40
FOR MOST OF THE REGION WITH THE EXCEPTION BEING ALONG THE NEW YORK
BORDER. WINDS SHOULD REMAIN GUSTY SATURDAY MORNING. THE BETTER
CHANCE FOR FROST WILL BE SUNDAY MORNING...TEMPERATURES WILL BE
SLIGHTLY WARMER BUT THE WINDS SHOULD BE LIGHT TO CALM. THERE
SHOULD BE A MODERATION INTO THE MIDDLE OF NEXT WEEK WITH TEMPS
GETTING BACK TO NEAR NORMAL AROUND 5/28.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
MAIN FRONT AND ACTION ACROSS NY STATE...TOOK MENTION OF SHOWERS
AND STORMS OUT OF ALL SITES BUT BFD. LEFT VCSH IN BFD UNTIL 03Z.
SOME FOG LATER...BASED MAINLY ON WHAT WENT ON LAST NIGHT.
NOT SEEING MUCH DIFFERENCE FOR WED...VERY SIMILAR TO TODAY...
WILL BE IN THE WARM SECTOR...WITH NOT MUCH GOING ON.
MORE IN THE WAY OF WIDESPREAD SHOWERS AND STORMS LATER THU
INTO THU NIGHT. COULD BY BUSY ACROSS THE FAR SE THU NIGHT...
IF A WAVE FORMS ON THE FRONT.
COOLER AND BREEZY FOR FRIDAY INTO SUNDAY...AS A STRONG COLD
FRONT DROPS SE OF PA.
HO
.OUTLOOK...
THU...SCT THUNDERSTORM IMPACTS POSSIBLE...MAINLY IN THE PM.
FRI-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...LAMBERT/STEINBUGL
LONG TERM...CERU/STEINBUGL
AVIATION...LAMBERT/MARTIN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
309 PM CDT MON MAY 20 2013
.SHORT TERM...THROUGH TUESDAY
AXIS OF SHOWERS HAS SHIFTED INTO THE EASTERN CWA THIS
AFTERNOON...WITH A BREAK FOR COUNTIES WEST OF ABERDEEN. THIS
BREAK WILL BE SHORT LIVED AS RADARS UPSTREAM IN NORTH DAKOTA ARE
QUITE ACTIVE...WITH WIDESPREAD LIGHT/MODERATE RAINFALL. HRRR AND
RUC GUIDANCE PIVOTS THIS MOISTURE BACK OVER THE CWA THIS EVENING
AND PERSISTS WELL INTO TUESDAY. MOST OF THE AREA HAS BEEN ABLE TO
HANDLE THE MOISTURE THUS FAR...WITH A FEW SPOTS REPORTING RISING
WATER IN DITCHES/CREEKS BUT NOT MUCH IMPACT OTHERWISE. SREF
PROBABILITIES FOR GREATER THEN A QUARTER INCH ARE HIGHEST ACROSS
OUR NORTHER MISSOURI COUNTIES...AN AREA THAT HAS NOT RECEIVED MUCH
DROUGHT RELIEF THIS SPRING...AND THUS THINK AREA CAN HANDLE THE
ADDITIONAL 1/2 INCH RAIN. SOILS FARTHER SOUTH AND EAST MAY BE LESS
FORGIVING AND WILL NEED TO BE MONITORED THIS EVENING/OVERNIGHT FOR
WATER ISSUES.
AS THE STACKED LOW CONTINUES TO DRIFT EAST TUESDAY...LIFT WEAKENS
WITH SOME DRIER AIR ENTRAINMENT RESULTING IN LOWER PROBABILITY FOR
PRECIPITATION AND QPF. TEMPERATURES THIS PERIOD WILL REMAIN BELOW
NORMAL AND CHANGE LITTLE THANKS TO CLOUD COVER.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
AS THE PERIOD OPENS...A DECAYING UPPER LOW CIRCULATION OVER THE
REGION WILL BE SLOWLY DRIFTING SOUTHEAST OUT OF THE AREA.
CONTINUED WRAP-AROUND MOISTURE COMBINED WITH SOME WEAK TROWALESQUE
FORCING/LIFT WILL KEEP POPS/RAIN SHOWERS MENTION GOING TUESDAY
NIGHT INTO WEDNESDAY AS THIS LOW PULLS AWAY FROM THE REGION.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT SHOULD BE DRY FORECAST
PERIODS WHILE A TRANSIENT HIGH-AMPLITUDE LONGWAVE HIGH PRESSURE
RIDGE WORKS THROUGH THE REGION.
BY FRIDAY...LOW LEVEL RETURN FLOW IS IN FULL SWING AND POPS FOR
SHOWERS AND THUNDERSTORMS MAKE THEIR RETURN TO THE FORECAST AS MID
AND UPPER LEVEL FLOW TAKES ON A RATHER PROLONGED PERIOD OF SWRLY
FLOW...THAT IS CURRENTLY PROGGED BY THE GFS AND ECMWF TO LAST
RIGHT INTO MONDAY.
THE COOLEST TEMPS DURING THE PERIOD LOOK TO BE TUESDAY NIGHT AND
WEDNESDAY BEFORE THE WARMING TREND ENSUES. BY THE
WEEKEND...TEMPERATURES SHOULD BE MUCH CLOSER TO CLIMO NORMAL.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AREA OF RAIN PIVOTING THROUGH KABR AND KPIR...EXITING KMBG...WITH
A SECOND AREA OF SHOWERS OVER/NORTH OF KATY. MOST OF THE RAIN IS
LIGHT WITH VFR VISBY AND MVFR CIGS...THOUGH HEAVIER POCKETS ARE
RESULTING IN IFR CIGS. THIS LINE IS CLEARING KMBG SO EXPECT
IMPROVING CONDITIONS...HOWEVER ANOTHER BAND OF MODERATE RAIN IS
SET TO PIVOT DOWN OUT OF NORTH DAKOTA THIS EVENING. FOR
KATY...BEING IN A WARMER/UNSTABLE AIRMASS...A FEW WEAK
THUNDERSTORMS COULD POP FOR A FEW HOURS THIS AFTERNOON.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...CONNELLY
LONG TERM...DORN
AVIATION...CONNELLY
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
603 PM CDT MON MAY 20 2013
.UPDATE...FOR AVIATION.
&&
.AVIATION...
00Z TAFS...UPPER LEVEL RIDGE WILL CONTINUE TO BE THE MAIN
INFLUENCE WITH FAIR WX THROUGH THIS EVENING. SOME MVFR BR OR
PERHAPS PATCHY STRATUS IS POSSIBLE TOWARD DAYBREAK. S WINDS WILL
BECOME SOMEWHAT GUSTY ON TUESDAY...TO 20KT AT TIMES...ESPECIALLY
FOR CKV. THE RIDGE WILL BEGIN TO MOVE EAST WITH AN APPROACHING
DISTURBANCE BRINGING A CHANCE FOR TSRA BY THE END OF THE PERIOD.
COVERAGE WILL BE GENERALLY ISOLD...BUT COVERAGE WILL BE INCREASING
FROM THE WEST...SO INCLUDING A VCTS FOR CKV AFTER 21Z.
13
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/
AFTERNOON CU DEVELOPMENT IS WIDESPREAD ACROSS THE MID STATE THIS
AFTERNOON AS DEWPOINTS HAVE CONTINUED TO RISE. MID LEVEL CAP IS
RATHER STRONG ACCORDING TO THE 12Z SOUNDING FROM THIS MORNING. THE
HIGHER DEWPOINTS HAVE ACTED TO LOWER CONVECTIVE TEMPS BUT CURRENT
TEMPS ARE STRUGGLING TO RISE GIVEN THE EXTRA CLOUD COVER.
FOR TONIGHT`S FORECAST...WILL INCLUDE A 20 POP BUT ONLY FOR THE
NW. THIS IS IN LINE WITH THE HRRR REFLECTIVITY FCST WHICH SHOWS
LITTLE IF ANY DEVELOPMENT. OVERALL...IT JUST APPEARS THAT THERE IS
TOO MUCH VERTICAL DRYNESS IN PLACE.
A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL BE IN THE FCST AGAIN FOR
TUESDAY. MOISTURE LEVELS SHOULD BE HIGHER AND WE DO SEE MORE 18Z CAP
EROSION WITH THE GFS MODEL. THE INCREASE IN MOISTURE WILL BE AIDED
BY AN APPROACHING FRONTAL BOUNDARY WHICH WILL IMPACT THE AREA LATE
TUESDAY NIGHT AND INTO WEDNESDAY. AT THAT TIME...A SLIGHT RISK OF
SEVERE WEATHER IS IN THE FCST FOR OUR NW COUNTIES. BEST OMEGA
FORCING APPEARS TO BE AROUND 06Z WEDNESDAY ACROSS WESTERN TN.
BUT...THERE COULD BE A FEW STRONGER CELLS OVER THAT SAME AREA
EARLIER ON TUES AFTERNOON. STORM MOTION SHOULD RUN FROM SW TO NE.
SHOWERS AND TSTMS TO PERSIST INTO WEDNESDAY. ITS IMPORTANT TO NOTE
HOWEVER THAT OVERALL POPS WITH THIS SYSTEM ARE NOT DRASTICALLY HIGH.
IN FACT...MODELS NOT LEANING TOWARD DEEP MOISTURE WITH A WIDESPREAD
AREA OF RAIN OCCURRING. NEVERTHELESS...POPS IN THE 40-60 PERCENT
RANGE WILL BE INCLUDED FOR TUESDAY NT INTO WEDNESDAY. AFTER A FEW
LINGERING SHOWERS ON THURSDAY ACROSS THE PLATEAU...CLEARING WILL
OCCUR WITH DRIER AIR MOVING IN.
FOR THE NEAR TERM TEMPS...WILL AGAIN UNDERCUT THE HIGH TEMPS FOR
TUESDAY AND WEDNESDAY. OVERNIGHT LOWS FROM THE GUIDANCE APPEARS
REASONABLE.
IN THE EXT FCST...NICE LATE MAY CONDITIONS ARE ON TAP FOLLOWING THE
FROPA WHICH WAS MENTIONED IN THE SHORT TERM TIME FRAME.
THUS...SUNSHINE TO RETURN IN EARNEST FOR FRIDAY AND INTO THE
WEEKEND. THERMAL TROUGHING WILL BE SLOW TO GIVE WAY AND
THUS...MOSTLY SUNNY SKIES WITH BELOW NORMAL TEMPS AND LOWER
HUMIDITY LEVELS WILL PREVAIL THU THROUGH SAT. SUNDAY AND MONDAY...UPPER
RIDGING AND HEIGHT RISES WILL BE ON TAP. THIS WILL EQUATE TO HIGH
TEMPS BACK UP INTO THE 80S. BUT...STILL NOT SEEING ANY APPRECIABLE
PRECIP CHANCES THROUGH MONDAY.
21
&&
.OHX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
324 PM CDT MON MAY 20 2013
DISCUSSION...
AFTERNOON CU DEVELOPMENT IS WIDESPREAD ACROSS THE MID STATE THIS
AFTERNOON AS DEWPOINTS HAVE CONTINUED TO RISE. MID LEVEL CAP IS
RATHER STRONG ACCORDING TO THE 12Z SOUNDING FROM THIS MORNING. THE
HIGHER DEWPOINTS HAVE ACTED TO LOWER CONVECTIVE TEMPS BUT CURRENT
TEMPS ARE STRUGGLING TO RISE GIVEN THE EXTRA CLOUD COVER.
FOR TONIGHT`S FORECAST...WILL INCLUDE A 20 POP BUT ONLY FOR THE
NW. THIS IS IN LINE WITH THE HRRR REFLECTIVITY FCST WHICH SHOWS
LITTLE IF ANY DEVELOPMENT. OVERALL...IT JUST APPEARS THAT THERE IS
TOO MUCH VERTICAL DRYNESS IN PLACE.
A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL BE IN THE FCST AGAIN FOR
TUESDAY. MOISTURE LEVELS SHOULD BE HIGHER AND WE DO SEE MORE 18Z CAP
EROSION WITH THE GFS MODEL. THE INCREASE IN MOISTURE WILL BE AIDED
BY AN APPROACHING FRONTAL BOUNDARY WHICH WILL IMPACT THE AREA LATE
TUESDAY NIGHT AND INTO WEDNESDAY. AT THAT TIME...A SLIGHT RISK OF
SEVERE WEATHER IS IN THE FCST FOR OUR NW COUNTIES. BEST OMEGA
FORCING APPEARS TO BE AROUND 06Z WEDNESDAY ACROSS WESTERN TN.
BUT...THERE COULD BE A FEW STRONGER CELLS OVER THAT SAME AREA
EARLIER ON TUES AFTERNOON. STORM MOTION SHOULD RUN FROM SW TO NE.
SHOWERS AND TSTMS TO PERSIST INTO WEDNESDAY. ITS IMPORTANT TO NOTE
HOWEVER THAT OVERALL POPS WITH THIS SYSTEM ARE NOT DRASTICALLY HIGH.
IN FACT...MODELS NOT LEANING TOWARD DEEP MOISTURE WITH A WIDESPREAD
AREA OF RAIN OCCURRING. NEVERTHELESS...POPS IN THE 40-60 PERCENT
RANGE WILL BE INCLUDED FOR TUESDAY NT INTO WEDNESDAY. AFTER A FEW
LINGERING SHOWERS ON THURSDAY ACROSS THE PLATEAU...CLEARING WILL
OCCUR WITH DRIER AIR MOVING IN.
FOR THE NEAR TERM TEMPS...WILL AGAIN UNDERCUT THE HIGH TEMPS FOR
TUESDAY AND WEDNESDAY. OVERNIGHT LOWS FROM THE GUIDANCE APPEARS
REASONABLE.
IN THE EXT FCST...NICE LATE MAY CONDITIONS ARE ON TAP FOLLOWING THE
FROPA WHICH WAS MENTIONED IN THE SHORT TERM TIME FRAME.
THUS...SUNSHINE TO RETURN IN EARNEST FOR FRIDAY AND INTO THE
WEEKEND. THERMAL TROUGHING WILL BE SLOW TO GIVE WAY AND
THUS...MOSTLY SUNNY SKIES WITH BELOW NORMAL TEMPS AND LOWER
HUMIDITY LEVELS WILL PREVAIL THU THROUGH SAT. SUNDAY AND MONDAY...UPPER
RIDGING AND HEIGHT RISES WILL BE ON TAP. THIS WILL EQUATE TO HIGH
TEMPS BACK UP INTO THE 80S. BUT...STILL NOT SEEING ANY APPRECIABLE
PRECIP CHANCES THROUGH MONDAY.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 68 89 67 82 / 05 20 50 70
CLARKSVILLE 68 87 65 82 / 10 30 60 50
CROSSVILLE 64 85 65 77 / 10 30 40 70
COLUMBIA 68 89 67 82 / 05 20 40 60
LAWRENCEBURG 66 88 67 82 / 05 20 40 60
WAVERLY 68 87 66 82 / 10 30 60 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
906 PM CDT TUE MAY 21 2013
.DISCUSSION...CONVETION HAS FAILED TO DEVELOP AS OF WRITING AS SSW
FLOW FROM H95 TO H7, PER 00Z AREA RAOBS, IS LIKELY NEGATING CONVECTIVE
DEVELOPMENT. LATEST AVAILABLE HRRR AND 18Z TTU WRF ALSO INDICATE
ONLY LOW CHANCES OF PRECIP DEVELOPING TONIGHT. THUS...HAVE LOWERED
POPS FOR TONIGHT AREAWIDE. STILL THINK A THIN BAND OF SHOWERS AND
A FEW RUMBLES OF THUNDER WILL DEVELOP OVERNIGHT...PRIMARILY ACROSS
NORTHERN AND NE ZONES. WILL CONTINUE TO MONITOR SITUATION THROUGH
THE NIGHT. OTHERWISE...ONLY OTHER CHANGE OF SIGNIFICANCE WAS TO
INCLUDE MENTION OF HAZE AND SMOKE FARTHER INLAND TONIGHT AS SMOKE
FROM AGRICULTURAL FIRES OVER STATE OF YUCATAN MEX CONTINUES TO
IMPACT S TX. AIR PARTICULATES WILL LIKELY POOL ALONG STALLING WEAK
SFC FRONT ACROSS NORTHERN ZONES TONIGHT RESULTING IN A
CONTINUATION OF HAZE/SMOKINESS THROUGH WEDNESDAY. UPDATED PRODUCTS
TO BE SENT SHORTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 76 89 75 92 75 / 10 20 10 10 10
VICTORIA 75 89 73 90 74 / 20 20 10 10 10
LAREDO 76 97 76 98 75 / 10 10 10 10 10
ALICE 75 93 73 93 75 / 10 20 10 10 10
ROCKPORT 76 80 75 86 75 / 10 10 10 10 10
COTULLA 73 96 73 98 74 / 10 10 10 10 10
KINGSVILLE 76 91 74 92 75 / 10 20 10 10 10
NAVY CORPUS 76 84 75 84 75 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1203 AM CDT MON MAY 20 2013
.AVIATION...
FOR THE 06Z TAFS...NO SIGNIFICANT CHANGES IN THINKING FROM
PREVIOUS FORECAST...SO LEFT PREVIOUS DISCUSSION INCLUDED BELOW.
BUMPED UP THE TIMING OF STRATUS BASED ON IR SATELLITE IMAGERY OF
STRATUS SURGING NORTH ON THE 50 KT LOW LEVEL JET LATE THIS
EVENING.
THE DFW CWSU INDICATED THAT SEVERAL PILOTS AROUND DFW AIRSPACE
TODAY MENTIONED REDUCED VISIBILITIES WHILE IN FLIGHT/LANDING DUE
TO SMOKE TRAPPED UNDER THE STRONG CAPPING INVERSION OVER NORTH TX
TODAY. THE SMOKE CAME FROM FIRES IN NORTHERN MEXICO. THIS CAP IS
LIKELY TO REMAIN IN PLACE TOMORROW...SO THIS THIN LAYER OF SMOKE
WILL LIKELY CONTINUE TO REDUCE VISIBILITIES FOR PILOTS LANDING
AROUND NORTH TX AIRPORTS ON MONDAY. THERE IS NOT REALLY ANY WAY TO
ACCOUNT FOR THIS IN THE TAFS...THE SMOKE IS NOT THICK ENOUGH TO
RESULT IN A CLOUD LAYER...AND THE REDUCED VISIBILITIES OCCUR 4-6
THOUSAND FEET ALOFT AND NOT AT THE SURFACE. THEREFORE MENTIONED
THE ELEVATED SMOKE LAYER HERE AS SOME SORT OF HEADS UP TO PILOTS
THAT THIS THIN SMOKE LAYER IS LIKELY TO PERSIST THROUGH MONDAY.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
FOR THE 00Z TAFS...THUNDERSTORM CHANCES AND TIMING THE ONSET OF
MVFR STRATUS ARE THE PRIMARY FORECAST CONCERNS THROUGH THE VALID
FORECAST PERIOD.
THUNDERSTORM CHANCES...WENT AHEAD AND LEFT THUNDERSTORMS OUT OF
THE METROPLEX AREA TAFS FOR THIS EVENING BASED LARGELY ON
SATELLITE OBSERVATIONS. THE LATEST RAP FORECAST SOUNDINGS
INDICATED THAT THE CAP OVER THE DFW AREA WOULD ERODE BY 02Z
POSSIBLY RESULTING IN THUNDERSTORMS NEAR AREA TAF SITES. VISIBLE
SATELLITE IMAGERY INDICATES FLAT CUMULUS CLOUDS WHILE IR SATELLITE
IMAGES SHOW CLOUD TOP TEMPERATURES HOLDING STEADY AT THE TIME OF
THIS DISCUSSION. EARLY RESULTS FROM THE 00Z FWD RAOB INDICATE A
SUBSTANTIAL CAP REMAINS IN PLACE OVER THE METROPLEX...HOWEVER AN
AIRCRAFT SOUNDING TAKING OFF FROM KDAL DID INDICATE A WEAKER CAP.
EITHER WAY...A CAP REMAINS IN PLACE AND IN THE ABSENCE OF STRONG
LIFT...DO NOT SEE A REASON FOR STORMS TO INITIATE NEAR AREA TAF
SITES THIS EVENING OR OVERNIGHT.
FOR TOMORROW...AN UPPER LEVEL DISTURBANCE OVER UTAH IS EXPECTED TO
MOVE TOWARDS THE REGION OVER THE NEXT 24 TO 36 HRS. THIS WILL
RESULT IN BETTER UPPER LEVEL SUPPORT AND LIFT ALONG THE DRYLINE BY
LATE TOMORROW AFTERNOON RESULTING IN A HIGHER CONFIDENCE FORECAST
FOR THUNDERSTORMS. STORMS THAT DEVELOP ALONG THE DRYLINE WOULD
LIKELY NOT REACH THE METROPLEX UNTIL AFTER 23Z OR 6 PM CDT. WENT
AHEAD WITH A MENTION OF VCTS IN ALL METROPLEX AREA TAFS AFTER THIS
TIME DUE TO THE HIGHER CONFIDENCE IN THE CLOSE PROXIMITY OF
STORMS. A CAPPING INVERSION IS EXPECTED TO REMAIN IN PLACE OVER
THE METROPLEX TOMORROW AFTERNOON...SO ITS DIFFICULT TO KNOW
WHETHER STORMS WILL BE ABLE TO OVERCOME THIS CAP OR NOT TO MOVE
DIRECTLY OVER AREA TAF SITES. EITHER WAY...THE STORMS ARE EXPECTED
TO BE CLOSE ENOUGH TO CAUSE TRAFFIC HEADACHES AT AREA AIRPORTS SO
THE VCTS IS IN THE FORECAST FOR PLANNING PURPOSES MORE THAN
ANYTHING ELSE AT THIS POINT.
MVFR STRATUS...NO CHANGES MADE TO THE PREVIOUS FORECAST. WE WILL
ONCE AGAIN HAVE A STRONG LOW-LEVEL JET OF 50 KTS OR GREATER OVER
NORTH TX TONIGHT. THIS SHOULD RESULT IN A SIMILAR STRATUS TIMING
TO THIS MORNING WHERE STRATUS BUILT OVER METROPLEX TAF SITES AFTER
11Z. STRATUS SHOULD SCATTER OUT OR LIFT TO VFR LEVELS QUICKLY WITH
DRIER AIR ABOVE THE STRATUS DECK ABOVE THE CAP.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 328 PM CDT SUN MAY 19 2013/
THE DRYLINE HAS REACHED A LINE FROM WICHITA FALLS TO GRAHAM TO
BROWNWOOD WHERE IT WILL LIKELY STALL BEFORE RETREATING WEST THIS
EVENING. THE MAIN FORECAST CONCERN THROUGH THIS EVENING IS
WHETHER STORMS WILL INITIATE ALONG THE DRYLINE AND THE AMOUNT OF
COVERAGE. AS DISCUSSED IN THE MORNING UPDATE...MOST OF THE MODEL
GUIDANCE IS NOT INITIATING ANY CONVECTION IN OUR REGION THIS
EVENING DESPITE CIN BECOMING ALMOST NEGLIGIBLE ACROSS THE WESTERN
ZONES. HOWEVER THE RUC/HRRR/GFS HAVE NOT WAVERED AND ONE OF THE
HI-RES WRFS AT 12Z HAS NOW JOINED THE INITIATION CAMP. THE ISSUE
AT HAND IS LIKELY THAT TODAY/S STRONG WINDS AND DRY AIR ALOFT WILL
MAKE IT TOUGH FOR AN INFANT UPDRAFT TO BECOME ESTABLISHED AND
GROW INTO A SUPERCELL WITHOUT A SHORTWAVE TO AID IN LIFT. RIGHT
NOW THE BEST GUESS IS THAT 1 TO 3 STORMS WILL MANAGE TO DEVELOP
OVER THE WESTERN CWA BY EARLY EVENING...AND WILL CONTINUE THE
FORECAST OF 20-30 POPS WEST OF A LINE FROM SHERMAN TO DFW TO
LAMPASAS. LOCAL OBJECTIVE ANALYSIS INDICATES CAPE VALUES ARE FROM
2000-3000 J/KG OVER THE CWA AND AMPLE DEEP LAYER SHEAR EXISTS TO
SUPPORT VERY LARGE HAIL AND DAMAGING WINDS. AN ISOLATED TORNADO
WILL BE POSSIBLE BETWEEN 6 AND 8 PM WHEN LOW LEVEL WIND SHEAR
RAMPS UP JUST BEFORE THE SURFACE AIRMASS BECOMES TOO NEGATIVELY
BUOYANT WITH LOSS OF HEATING. STORMS MAY HOLD TOGETHER LONG ENOUGH
TO AFFECT LOCATIONS FARTHER TO THE EAST BY MID-LATE
EVENING...ESPECIALLY NORTH OF I-20...BUT SEVERE WEATHER POTENTIAL
WILL BE DIMINISHING. OTHERWISE A BREEZY AND MUGGY NIGHT IS IN
STORE FOR THE REGION.
THE STORM THREAT FOR MONDAY IS LOOKING GREATER ACROSS A LARGER
PART OF NORTH TEXAS. THE CIN WILL BE EVEN WEAKER THAN TODAY AND
ALMOST ALL OF THE MODELS ARE INDICATING STORM INITIATION IN THE
CWA. THE DRYLINE WILL BE ROUGHLY IN THE SAME LOCATION AS IT IS
TODAY. THE GFS AND NAM ARE MOST AGGRESSIVE WITH HEIGHT FALLS AND
CONVECTION ACROSS THE NW CWA...WHICH RAISES CONFIDENCE THAT THIS
AREA WILL LIKELY SEE SUPERCELL STORMS AND SEVERE WEATHER. EXPECT
SEVERAL SUPERCELLS TO DEVELOP ACROSS THE WESTERN ZONES...INCLUDING
SOME ISOLATED CELLS ACROSS THE SW ZONES. VERY HIGH INSTABILITY
AND AMPLE DEEP LAYER SHEAR WILL SUPPORT A THREAT OF SIGNIFICANT
SEVERE WEATHER INCLUDING GIANT HAIL...DAMAGING WINDS AND A FEW
TORNADOES. LOW LEVEL WIND SHEAR GETS STRONGER AFTER 7PM WITH 0-3KM
SRH VALUES ABOVE 300 M2/S2. SINCE THERE IS LESS CIN THERE IS MORE
TIME FOR EVENING SUPERCELLS TO TAP INTO THIS INSTABILITY AFTER
DARK WHICH IS WHAT IS RAISING OUR CONCERN FOR TORNADOES. HAVE
BUMPED UP POPS TO 30-50 PERCENT IN THE WESTERN ZONES...AND
RAISED THEM FOR THE CENTRAL AND NORTHEAST ZONES AS WELL...AS
SUPERCELLS WILL HEAD EASTWARD AND HOLD TOGETHER LONGER.
ON TUESDAY A WEAK COLD FRONT WILL BECOME DRAPED ACROSS THE CWA
FROM ROUGHLY PARIS TO DFW TO EASTLAND. HIGH TEMPS WILL BE A LITTLE
COOLER THIS DAY...BUT INSTABILITY WILL STILL BE VERY HIGH
ESPECIALLY ACROSS THE SOUTHERN ZONES. ALL MODEL GUIDANCE SHOWS
STRONG UPPER LEVEL FORCING OVER NORTH TEXAS TUESDAY AFTERNOON AS
THE TROUGH AXIS SWINGS THROUGH THE AREA. THIS WILL SET THE STAGE
FOR SCATTERED TO NUMEROUS SHOWERS AND STORMS THAT WILL LIKELY
DEVELOP ALONG THE FRONT TUESDAY AFTERNOON AND MOVE EAST AND
SOUTHEAST INTO THE NIGHTTIME HOURS. SINCE LOW LEVEL WIND FIELDS
RELAX A BIT...THESE STORMS MAY TEND TO ORGANIZE INTO A MCS/SQUALL
LINE OVER THE CENTRAL ZONES. OBVIOUSLY A SEVERE WEATHER THREAT
WILL EXIST WITH THIS CONVECTIVE EPISODE AS WELL. RAINFALL WILL
RANGE FROM A TRACE IN THE NW TO 1.5 INCHES IN THE SOUTHEAST ZONES.
EXPECT THIS CONVECTIVE EPISODE TO FINALLY EXHAUST THE ATMOSPHERE
AND PUSH THE BEST MOISTURE AND INSTABILITY SOUTHEAST OF THE AREA
BY WEDNESDAY MORNING. WILL KEEP WEDNESDAY DRY.
WEAK RIDGING SETS UP OVER THE AREA WEDNESDAY AND INTO NEXT
WEEKEND. SOUTHEAST WINDS WILL CONTINUE WHICH WILL KEEP LOW TEMPS
IN THE MID 60S TO NEAR 70...AND HIGHS IN THE MID 80S TO NEAR 90
EACH DAY. CONVECTION IS EXPECTED TO OCCUR OVER THE HIGH PLAINS
THURSDAY AND FRIDAY...AND WITH A SOUTHEASTERLY FLOW IN THE LOWEST
800MB WE WILL NEED TO KEEP AN EYE ON SOME OF THIS ACTIVITY MAKING
A RUN AT THE CWA DURING THE OVERNIGHT HOURS. SINCE THERE IS A LACK
OF STRONG NORTHWEST FLOW ALOFT IN THE MID LEVELS...BELIEVE
CONVECTION WILL DISSIPATE BEFORE REACHING MOST OF THE AREA...BUT
HAVE INSERTED A SLIGHT CHANCE IN THE NW ZONES THURSDAY AND FRIDAY
NIGHTS. WILL KEEP THE REMAINDER OF THE FORECAST DRY.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 71 90 71 88 67 / 5 20 40 50 50
WACO, TX 72 90 72 91 68 / 5 10 20 40 60
PARIS, TX 70 87 69 83 65 / 5 10 60 50 50
DENTON, TX 70 89 69 86 64 / 5 30 40 40 40
MCKINNEY, TX 70 89 70 85 65 / 5 20 40 50 50
DALLAS, TX 73 91 73 89 69 / 5 20 40 50 50
TERRELL, TX 70 89 71 87 68 / 5 10 30 50 60
CORSICANA, TX 71 89 72 88 69 / 5 10 20 40 60
TEMPLE, TX 71 90 72 92 69 / 5 10 20 40 60
MINERAL WELLS, TX 70 94 68 88 65 / 5 30 30 40 40
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
934 PM EDT TUE MAY 21 2013
.SYNOPSIS...
AN UPPER LEVEL AREA OF LOW PRESSURE WILL DRIFT EAST AND OFFSHORE
OVERNIGHT. A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE
CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL
PUSH A COLD FRONT THROUGH THE AREA THURSDAY...FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 915 PM EDT TUESDAY...
BAND OF WEAKENING CONVECTION ASSOCIATED WITH OLD OUTFLOW BAND TO
THE WEST CONTINUES TO FADE ALONG THE WESTERN SLOPES ATTM WHILE NEW
OUTFLOW HAS GIVEN RISE TO ADDED SHRA/TSRA OVER THE WESTERN RIDGES.
LATEST MESO ANALYSIS SHOWS STILL ENOUGH INSTABILITY TO KEEP STORMS
GOING A WHILE LONGER MOUNTAINS WITH SOME OF THIS COVERAGE PERHAPS
DEVELOPING ACROSS THE BLUE RIDGE WHERE THE BEST LEFTOVER CAPES
EXIST. APPEARS THE OVERALL SEVERE THREAT SHOULD SLOWLY FADE PER
LOSS OF HEATING BUT LOW WET BULBS AND LOTS OF DRY AIR ALOFT OFF
EVENING SOUNDINGS STILL SUPPORT AT LEAST ISOLATED SEVERE POTENTIAL
THROUGH MIDNIGHT ESPCLY IF STORMS BECOME MORE LINEAR. THEREFORE
NUDGED UP POPS TO LOW LIKELYS FAR WEST OVER THE NEW FEW HOURS
WHILE KEEPING A SCATTERED NATURE FARTHER EAST DESPITE THE LACK OF
COVERAGE OFF THE LATEST HRRR SHORTLY AFTER MIDNIGHT. LOW LEVELS
ESPCLY EAST SHOW A BIT MORE DRYING THIS EVENING WITH SOME LIGHT
MIXING ONGOING WHICH SHOULD SLOW DOWN FOG FORMATION UNTIL LATE
EXCEPT WHERE RAINFALL HAS ALREADY OCCURRED. HOWEVER MOIST
DEWPOINTS WILL HOLD TEMPS MOSTLY IN THE MUGGY 60S WITH ONLY THE
DEEPER VALLEYS AND SPOTS SEEING SHOWERS PERHAPS FALLING INTO THE
50S LATE.
WARM AND HUMID CONDITIONS CONTINUE ON WEDNESDAY IN THE SOUTHERLY
FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH.
INCREASED POPS FROM WEST TO EAST ON WEDNESDAY...WITH HIGHEST POPS
ALONG WESTERN MOUNTAINS. THE SWODY2 (DAY TWO CONVECTIVE OUTLOOK)
HAS THE SLIGHT RISK JUST TO OUR WEST ON WEDNESDAY. PLAYED HIGHS
TEMPERATURES COOLER ON WEDNESDAY WITH READINGS FROM THE MID 70S IN
THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 255 PM EDT TUESDAY...
HAVE A COUPLE DAYS MORE OF HUMID WEATHER BEFORE FRONT SWINGS ACROSS
THURSDAY AND BRINGS A RETURN TO LOWER DEWPOINTS.
UNTIL THEN...NO MAJOR CHANGES TO THE FORECAST. WEDNESDAY NIGHT A
PIECE OF SHORTWAVE ENERGY ARRIVES ACROSS THE CENTRAL APPALACHIANS
WHICH CREATES AN AREA OF SHOWERS AND STORMS...MAINLY AFFECTING THE
WRN EDGE OF THE FORECAST AREA. THE BETTER PUSH OF THE FRONT ON
THURSDAY COMBINED WITH BETTER UPPER SUPPORT SHOULD BRING SOME
ENHANCED THREAT OF SHOWERS AND STORMS. TIMING OF THIS FRONT DOES
VARY SOMEWHAT FROM THE MODELS BUT ENOUGH AGREEMENT TO HAVE HIGH
CHANCE TO LIKLEY IN THE AREA THURSDAY. TIMING ALSO GIVES ISSUES TO
SVR THREAT. ATTM...EXPECT A LINE OF SHRA/TSRA TO BE IN THE MTNS IN
THE MORNING AND MOVING INTO THE PIEDMONT BY EARLY AFTERNOON. NOT
SEEING A LOT OF HEATING AS CLOUDS WILL BE GENEROUSLY SPREAD. ONE
AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC
PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT
THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF
VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 PM EDT TUESDAY...
CONVECTION REMAINS QUITE ISOLATED ACROSS THE REGION THIS EVENING
WITH MOST COVERAGE OVER NW NORTH CAROLINA WELL SW OF THE TAF
SITES. MAIN CONCERN WILL BE WITH THE COMPLEX OF SHRA/TSRA
ASSOCIATED WITH AN OLD OUTFLOW HEADING NE OUT OF TN/KY DURING THE
NEXT FEW HOURS. LATEST SHORT RANGE GUIDANCE BRINGS SOME OF THIS AS
FAR EAST AS THE BLUE RIDGE AROUND MIDNIGHT BEFORE IT FADES. THUS
MAY HAVE A STORM OR SHRA AFFECT KBLF/KLWB DURING THE LATE EVENING
WITH A BAND/CLUSTER OF SHRA/TSRA NEAR KBCB/KROA TOWARD
MIDNIGHT PENDING HOW FAR EAST THE PRECIP MAKES IT AFTER LOSS OF
HEATING AND LITTLE UPPER SUPPORT. GIVEN UNCERTAINTY WILL COVER
MAINLY WITH VCTS/VCSH FOR NOW AND AMEND IF STORMS DO INDEED GET
CLOSER.
OTHER CONCERN AGAIN WITH FOG LATE ESPCLY NEAR WHERE ANY RAINFALL
OCCURS GIVEN SUCH A MUGGY ENVIRONMENT. LATEST FORECAST RAOB
SOUNDINGS SUGGEST QUITE A BIT OF PATCHY FOG BUT LIKELY NOT AS
WIDESPREAD AS THIS MORNING EXCEPT IN SPOTS WHERE A SHRA PASSES.
REGARDLESS OF SHRA COVERAGE...APPEARS KLWB STILL HAS THE BEST
CHANCE TO DROP TO LIFR IN FOG WEDNESDAY MORNING WITH A PERIOD OF
IFR ELSW EXCLUDING KBLF/KROA WHERE ONLY BRIEF MVFR POSSIBLE AT
THIS TIME.
EXPECT A QUICK IMPROVEMENT TO CONDITIONS ON WEDNESDAY WITH THE
ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK
ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT
AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY
20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN
SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB
WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER
SCTD/BKN 5-6K FT CU FIELDS.
THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD
OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY.
THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG.
HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY
AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/JH/KK
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/JH/KK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
331 PM CDT MON MAY 20 2013
.VERY SHORT TERM...TONIGHT AND TUESDAY. FORECAST CONFIDENCE...LOW
TO MEDIUM.
BIGGEST CONCERN INTO TONIGHT IS TIMING AND STRENGTH OF EXPECTED
THUNDERSTORMS. SPC IS MAINTAINING A SLIGHT RISK FOR SEVERE STORMS
ACROSS THE FORECAST AREA. LATEST NAM AND RAP SOUNDINGS AGREE THAT
THE ENVIRONMENT STILL LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS.
WITH THE CONTINUED SUNSHINE...SHOULD SEE SFC BASED CAPE VALUES GET
IN THE 1000-1500 J/KG RANGE BY LATE AFTERNOON OR EARLY EVENING.
ADDITIONALLY...PLENTY OF 0-6 KM BULK SHEAR...GENERALLY 35-45 KT.
PLENTY OF MOISTURE AS WELL...WITH PRECIPITABLE WATER VALUES
INCREASING TO AROUND 1.25 INCHES THIS EVENING...ABOVE CLIMATOLOGICAL
NORMALS.
WITH A DECENT ENVIRONMENTAL SETUP...WILL JUST BE WAITING FOR THE
TRIGGER. TIMING OF UPSTREAM SHORTWAVE ALONG WITH LATEST HRRR AND
LOCAL WRF4L MODEL INDICATE THAT CONVECTION MAY HOLD OFF ACROSS
SOUTHERN WISCONSIN UNTIL THE MID-EVENING HOURS. ONE THING TO NOTE IS
THAT THE LAST FEW RUNS OF MESOSCALE MODELS HAVE BEEN ALL OVER THE
PLACE WITH CONVECTIVE SOLUTIONS FOR THIS EVENING...SO NOT A TON OF
CERTAINTY AT THIS POINT.
LOW PRESSURE REMAINING TO THE WEST WILL KEEP SOUTHERN WISCONSIN IN A
WARM AN UNSTABLE ENVIRONMENT THROUGH TUESDAY...THUS CHANCE FOR
THUNDERSTORMS WILL CONTINUE. SIMILAR TO TODAY...NOT A LOT OF
CERTAINTY IN TIMING AND PLACEMENT OF DEVELOPMENT. ANY STORMS THAT DO
DEVELOP TOMORROW WILL HAVE THE CHANCE TO BECOME STRONG TO
SEVERE...WITH SPC MAINTAINING A SLIGHT RISK FOR SEVERE STORMS.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY. FORECAST CONFIDENCE
MEDIUM.
CLOSED LOW FINALLY BEGINS TO MOVE AS IT OPENS AND BECOMES PHASED
WITH TROUGH DROPPING TOWARD THE NORTHERN GREAT LAKES AS IT ROTATES
AROUND POLAR VORTEX JUST EAST OF HUDSON BAY.
ONE MORE ROUND OF CONVECTION EXPECTED WITH 500 MB SHORT WAVE TUE
NGT/WED AM WITH LAYER Q-VECTOR MAXIMA AND FRONTOGENETIC FORCING
INDICATING BEST CHANCES MAINLY AFTER 06Z WED...WITH MAX
FRONTOGENETIC FORCING OVER THE CWA AT 12Z WED. FORCING LIFTS
THRU...STALLS AND THEN DROPS BACK ACROSS REGION AS SYSTEM OPENS AND
MOVES RIGHT ACROSS THE STATE...WITH MID-LEVEL TROF AXIS SOUTH OF CWA
AROUND 18Z THURSDAY. THE SLIGHTLY DIFFERING SOLUTIONS TO TIMING AND
STRUCTURE AMONG THE MODELS LEADS TO VARIOUS AMOUNTS OF QPF. WENT
WITH BLENDED QPF AMOUNTS WITH A LEAN TOWARD THE HIGHER NUMBERS...BUT
IF CONVERGENCE BAND SETS UP RIGHT OVER THE REGION...THEN AMOUNTS
COULD GO EVEN HIGHER AND AREAL/RIVER FLOODING COULD COME INTO PLAY.
NOT ENOUGH CONFIDENCE TO RE-ISSUE AN EFS AT THIS TIME BUT WILL NEED
TO BE WATCHED.
TEMPERATURES DO NOT FALL MUCH TUESDAY NIGHT WITH CLOUDS AND THE AREA
STAYING ROUGHLY TO THE WARM SIDE OF THE LOW AS IT MOVES THROUGH SO
FOLLOWED LOWS CLOSER TO THE WARMER GUIDANCE NUMBERS. HIGHS WEDNESDAY
WILL BE AROUND MID DAY...THEN COOL WITH WINDS TURNING NORTHERLY AS
SURFACE LOW/TROUGH SLIDES BY...THOUGH LINGERING TROUGHINESS WILL
PREVENT MUCH OF A GRADIENT UNTIL CLOSER TO THURSDAY MORNING. HIGHS
THURSDAY WILL ONLY GET TO THE MID 60S WELL INLAND...WITH 50S ALONG
THE LAKE.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE
AMOUNT OF COOLING VARIES WITH DEPTH OF EVOLVING 500 MB TROUGH OVER
EASTERN CANADA. OMEGA BLOCK SETS UP WITH AN AMPLIFYING RIDGE OVER
THE PLAINS BETWEEN EASTERN CANADA VORTEX AND CLOSED LOW OVER THE
PACIFIC NW...WITH THE FORECAST AREA REMAINING UNDER THE NW FLOW OF
THE EASTERN TROUGH THROUGH SATURDAY. LESS AMPLIFIED ECMWF ALLOWS
WARM AIR ADVECTION PRECIPITATION AHEAD OF SHORT WAVE UNDERCUTTING
THE RIDGE AND ASSOCIATED INVERTED SURFACE TROUGH CROSSING THE REGION
FRIDAY NIGHT AND SATURDAY. MORE DOMINANT SURFACE HIGH PRESSURE WITH
MORE AMPLIFIED GFS/GEM HOLDS PCPN CHANCES OFF UNTIL SATURDAY
AFTERNOON/SATURDAY NIGHT ON THE GEM...AND NOT UNTIL SUNDAY WITH THE
GFS. WHILE THE CONSENSUS BLEND HAS PRECIPITATION CHANCES THROUGH THE
HOLIDAY WEEKEND DUE TO THE TIMING SPREAD IN THE MODELS...THERE WILL
BE DRY PERIODS. TEMPERATURES WILL BE BELOW NORMAL...WITH HIGHS
TRYING TO GET BACK INTO THE LOWER 70S MONDAY AWAY FROM THE LAKE.
&&
.AVIATION/00Z TAFS/...
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH TUESDAY...THOUGH
LOWER CIGS/VSBYS POSSIBLE IN ANY THUNDERSTORMS. BIG ISSUE THROUGH
TOMORROW REMAINS TIMING ROUNDS OF THUNDERSTORMS. LOOKS QUIET THROUGH
LATE AFTERNOON...WITH LATEST MESOSCALE MODELS SUGGESTING DEVELOPMENT
POSSIBLE THIS EVENING AND INTO THE NIGHT. TOOK A STAB AT BEST CHANCE
FOR STORMS IN THE TAFS...THOUGH STILL HAD TO KEEP IT FAIRLY GENERAL
DUE TO A GOOD AMOUNT OF UNCERTAINTY. CHANCE FOR STORMS WILL CONTINUE
TUESDAY.
&&
.MARINE...
WILL LIKELY SEE GUSTS TO 25 KNOTS FROM NORTH POINT LIGHT SOUTHWARD
INTO EARLY EVENING...UNTIL DAYTIME HEATING/MIXING DECREASES. WILL
THUS KEEP THE SMALL CRAFT ADVISORY GOING UNTIL 01Z. FARTHER
NORTH...COULD SEE A FEW GUSTS TO 25 KNOTS...BUT OVERALL GRADIENT IS
A BIT WEAKER. PLUS...WINDS CONTINUE TO HAVE AN ONSHORE COMPONENT AT
TIMES ACROSS THE NORTH...WHICH SHOULD LIMIT GUST POTENTIAL DUE TO
THE STABLE AIRMASS OVER THE LAKE.
WINDS WILL MAINLY BE SOUTH TO SOUTHWEST THROUGH TUESDAY...SO OVERALL
FOG POTENTIAL WILL BE LIMITED. COULD SEE SOME FOG FOR A TIME IF
WINDS ARE SOUTHEAST LONGER THAN EXPECTED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR LMZ645-646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...DDV
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1235 PM CDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT MON MAY 20 2013
MAIN FORECAST CONCERN IS ON SEVERE WEATHER AND FLOODING POTENTIAL
TODAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED AN UPPER LOW OVER SOUTH DAKOTA AND NEBRASKA WITH RIDGING
AHEAD OF IT OVER MICHIGAN. THE UPPER LOW WAS MOSTLY CUT OFF WITH
RIDGING TO ITS NORTH OVER SOUTH CENTRAL CANADA. 500MB STANDARD
DEVIATIONS WERE 1-1.5 BELOW NORMAL WITH THE UPPER LOW. NUMEROUS
SHORTWAVES WERE EJECTING IN SOUTHWEST FLOW AHEAD OF THE UPPER
LOW...SOME OF WHICH ARE CONVECTIVELY PRODUCED. ONE FOR EXAMPLE WAS
LIFTING THROUGH NORTHWEST WISCONSIN WHICH BROUGHT RAIN TO MUCH OF
THE AREA DURING THE NIGHTTIME HOURS. RAP DATA ALSO SHOWED A LOW
LEVEL MOISTURE TRANSPORT ZONE WITH THIS MCV. FARTHER SOUTH...ANOTHER
LOW LEVEL MOISTURE TRANSPORT ZONE WAS NOTED IN SOUTHERN MISSOURI...
POINTING INTO SOUTHERN ILLINOIS. COMBINATION OF SUBSIDENCE IN THE
WAKE OF THE MCV AND SPLIT IN MOISTURE TRANSPORT HAS ALLOWED THE
PRECIPITATION TO DIMINISH SOUTH OF HWY 29. PLENTIFUL MOISTURE COMING
UP AHEAD OF THE UPPER LOW WITH PRECIPITABLE WATER VALUES OF 1.2-1.5
INCHES FROM EASTERN OK INTO SOUTEHRN WI. THERE WAS A MINIMA OF
PRECIPITABLE WATER FROM WESTERN KS INTO MUCH OF IA...THOUGH....
ASSOCIATED WITH A DRY SLOT SOUTH OF THE UPPER LOW. AT THE
SURFACE...LOW PRESSURE WAS SITUATED UNDER THE UPPER LOW WITH A WARM
FRONT EXTENDING EAST TO EAU CLAIRE WI. RAP 850MB TEMPS WERE IN THE
14-18C RANGE SOUTH OF THE FRONT IN THE FORECAST AREA.
MODELS ARE IN GOOD AGREEMENT OF KEEPING THE UPPER LOW NEARLY
STATIONARY OVER SOUTH DAKOTA. DESPITE ITS STATIONARY MOVEMENT...THE
WEATHER WILL BE QUITE A BIT DIFFERENT COMPARED TO YESTERDAY.
PRIMARILY THIS IS DUE TO THE UPPER FLOW AHEAD OF THE UPPER LOW
PROGGED MORE SOUTHWESTERLY VERSUS SOUTHERLY. ADDITIONALLY...THE
PLUME OF HIGHER PRECIPITABLE WATER IS PROGGED TO SLOWLY SHIFT EAST
THANKS TO THE UPPER LOW.
MOST OF THE FORECAST AREA IS INDICATED TO STAY IN THE WARM SECTOR
THROUGH TONIGHT...ALONG WITH EXISTING IN THAT SOUTHWEST FLOW FOR
SHORTWAVES TO COME THROUGH...BOTH FAVORABLE FOR THUNDERSTORM
DEVELOPMENT. HOWEVER...ONE QUESTION MARK IS MOISTURE. BASED ON A
AMDAR SOUNDING OUT OF OMAHA AT 04Z...THE 850MB DEWPOINTS FROM THE
20.00Z NAM WERE 6-7C TOO HIGH...THUS THE NAM BUILDS A LOT OF CAPE
QUICKLY THIS MORNING. THE RAP IS MUCH MORE SUBDUED HAVING THE AREA
ENCOMPASSED BY THE DRY AIR...ESPECIALLY WHEN LOOKING AT MLCAPE.
THINKING THE RAP IDEA IS MUCH MORE REPRESENTATIVE AND HAVE KEPT THE
AREA DRY THROUGH EARLY AFTERNOON. EVENTUALLY...THE RAP DOES CATCH UP
WITH THE CAPE LATE IN THE AFTERNOON THANKS TO EVAPOTRANSPORATION OF
MOIST SOILS. IN FACT...THE RAP SHOWS A DEFINITIVE DRY LINE IN THE
WARM SECTOR FORMING NEAR I-35 IN THE AFTERNOON. THIS DRY LINE SHOULD
SERVE AS A TRIGGER FOR CONVECTIVE DEVELOPMENT...ESPECIALLY IN
SOUTHEAST MN AND NORTHEAST IA. MAJORITY OF MODELS...INCLUDING HI
RESOLUTION ONES...SHOW THIS SCENARIO...WITH THE THUNDERSTORMS THEN
PROPAGATING NORTHEAST THROUGH THE EVENING. THE BEST 0-6KM SHEAR OF
GREATER THAN 35 KTS IS PROGGED OVER THE SOUTHEAST HALF OF THE
FORECAST AREA...OPPOSITE OF WHERE MOST OF THE CONVECTION WILL BE. ON
THE OTHER HAND...FREEZING LEVEL HEIGHTS ARE LOWER ON THE ORDER OF
10500 FT WHERE THE CONVECTION IS EXPECTED...THUS THERE COULD END UP
BEING MARGINALLY SEVERE HAIL. STORMS SHOULD GRADUALLY WEAKEN AS
INSTABILITY WANES LATE IN THE EVENING INTO THE OVERNIGHT HOURS. IT
SHOULD BE NOTED...IF FOR SOME REASON A STORM FIRES IN THE HIGHER
0-6KM SHEAR AREA THIS AFTERNOON...IT WOULD LIKELY BECOME
SUPERCELLULAR. AGAIN...THOUGH...THINK THIS IS A LOW PROBABILITY WITH
THAT AREA PERHAPS EVEN BEING CAPPED. SEE THE HYDROLOGY SECTION BELOW
FOR FLOODING CONCERNS.
CERTAINTLY THE ADDITIONAL RAIN FROM STORMS THIS AFTERNOON AND EARLY
EVENING WILL NOT HELP THE FLOODING MATTERS IN PORTIONS OF SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. HAVE KEPT THE FLASH FLOOD WATCH GOING
TO 00Z THIS EVENING...WHICH WORKS OUT WELL IN TERMS OF TIME BECAUSE
THE CONVECTION SHOULD MOSTLY BE EAST OF THERE BY THE EXPIRATION.
SHOULD SEE QUITE A BIT OF SUN TODAY AND WITH 850MB TEMPS HOVERING IN
THAT 14-18C RANGE...TEMPERATURES SHOULD EASILY CLIMB INTO THE UPPER
70S TO MID 80S. ANOTHER MILD NIGHT LIKELY TONIGHT WITH PLENTY OF
CLOUDS AND DEWPOINTS REMAINING UP IN THE 50S TO LOW 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 341 AM CDT MON MAY 20 2013
TUESDAY THROUGH THURSDAY...
MAIN FOCUS HERE IS ON THE EVOLUTION OF THE UPPER LOW. 20.00Z
ECMWF/GFS/CANADIAN/NAM ARE ALL IN PRETTY GOOD AGREEMENT HOLDING THE
UPPER LOW NEARLY STATIONARY ON TUESDAY...THEN GRADUALLY SHIFTING
EASTWARD TUESDAY NIGHT AND WEDNESDAY BEFORE IT GETS MORE OF A KICK
EAST WEDNESDAY NIGHT. THE KICK EAST IS IN RESPONSE TO A POTENT
TROUGH DROPPING SOUTH THROUGH MUCH OF EASTERN CANADA.
FOR TUESDAY...MUCH OF THE FORECAST AREA WEST OF THE MISSISSIPPI
RIVER LOOKS TO BE DRY-SLOTTED...THUS HAVE LOWERED PRECIPITATION
CHANCES. TO THE EAST...THERE ARE INDICATIONS THAT SOME DIURNAL
CONVECTION COULD FORM ALONG A COLD FRONT MARCHING EAST. INSTABILITY
IS PRETTY MEAGER IN THIS CASE COMPARED TO WHAT WE HAVE BEEN DEALING
WITH...THUS ANY CONVECTION SHOULD NOT GO SEVERE. BETTER SHOT FOR
SEVERE WEATHER WILL BE WELL SOUTH AND EAST OF THE FORECAST AREA.
HIGHEST PRECIPITATION CHANCES OVERALL ARE EXPECTED NORTH OF HWY 29
IN A LOW TO MID LEVEL FRONTOGENESIS ZONE.
AS THE UPPER LOW BEGINS TO PUSH EAST TOWARDS THE FORECAST AREA
TUESDAY NIGHT AND WEDNESDAY...DPVA INCREASES WHILE SIMULTANEOUSLY
THE LOW TO MID LEVEL FRONTOGENESIS ZONE DROPS SOUTH. THEREFORE...
INCREASING PRECIPITATION CHANCES SEEM REASONABLE... ESPECIALLY ON
WEDNESDAY WHEN THE TWO FORCING MECHANISMS ARE JUXTAPOSTED.
ADDITIONALLY...THERE COULD BE SOME DIURNAL ENHANCEMENT ON WEDNESDAY
BEING CLOSE TO OR UNDER THE COLD CORE OF THE UPPER LOW.
MODELS APPEAR TO BE TRENDING FASTER IN KICKING OUT THE UPPER LOW FOR
WEDNESDAY NIGHT AND THURSDAY...ENOUGH SO THAT THURSDAY MAY NOW END
UP DRY. WEDNESDAY NIGHT STILL LOOKS FAVORABLE FOR PRECIPITATION...
ESPECIALLY EAST OF THE MISSISSIPPI RIVER WHICH IS IN THAT
AFOREMENTIONED JUXTAPOSITION OF FORCING MECHANISMS.
DEFINITELY A COOLING TREND WILL TAKE PLACE FOR TUESDAY THROUGH
THURSDAY WITH THAT UPPER LOW COMING IN...AND THEN COME THURSDAY A
NORTHERLY FLOW ADVECTING AIR FROM CANADIAN HIGH PRESSURE TRYING TO
BUILD SOUTH INTO THE UPPER GREAT LAKES. 850MB TEMPS FALL FROM 11-13C
AT 12Z TUE TO 4-6C BY 12Z THU. WENT WITH A BLEND OF GUIDANCE FOR
HIGHS AND LOWS FOR NOW GIVEN NO SIGNAL TO LEAN TOWARDS WARMER OR
COLDER SCENARIO GIVEN THE FORECAST PATTERN.
THURSDAY NIGHT INTO NEXT WEEKEND...
20.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO ADVERTISE A
BLOCKED UP UPPER LEVEL FLOW PATTERN ACROSS NORTH AMERICA DURING THE
EXTENDED PORTION OF THE FORECAST. THE FLOW FEATURES DEEP TROUGHING
ALONG THE WEST COAST...RIDGING FROM THE PLAINS INTO THE NORTHWEST
TERRITORIES...AND MEAN TROUGHING FROM EASTERN CANADA INTO THE
MID-ATLANTIC REGION. WHAT THIS PATTERN MEANS FOR THE FORECAST AREA
IS A BATTLE BETWEEN DRY...CANADIAN HIGH PRESSURE AND A MORE HUMID
AIRMASS ADVECTING NORTH OUT OF THE GULF OF MEXICO UNDER THE UPPER
RIDGE. IT APPEARS DRY CONDITIONS SHOULD PREVAIL FOR THURSDAY NIGHT
AND FRIDAY...RESULTING FROM SUBSIDENCE IN THE WAKE OF THE EARLY TO
MID WEEK UPPER LOW. FROM FRIDAY NIGHT AND BEYOND...HAVE FOLLOWED A
CONSENSUS APPROACH AND SPREAD PRECIPITATION CHANCES ACROSS THE
FORECAST AREA...HIGHEST WEST OF THE MISSISSIPPI RIVER. THESE CHANCES
ARE A RESULT OF SURGES OF WARM ADVECTION. THE PRECIPITATION COULD
BECOME ENHANCED TOO AT TIMES AS JET STREAKS PROPAGATE BETWEEN THE
EASTERN CANADA TROUGH AND PLAINS RIDGING.
SOMETHING TO WATCH DURING THE EXTENDED IS POTENTIAL FOR FROST...
ESPECIALLY IN CENTRAL WISCONSIN. THURSDAY NIGHT ACCORDING TO 20.00Z
MODELS WOULD BE THE HIGHEST CHANCE...THOUGH CONFIDENCE IS NOT HIGH
ENOUGH TO EITHER MENTION FROST IN THE FORECAST OR DROP LOWS BELOW
40. OTHERWISE...TEMPERATURES SHOULD STAY MOSTLY BELOW NORMAL BEING
UNDER THE INFLUENCE OF THE CANADIAN HIGH AND A NORTHEAST FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1235 PM CDT MON MAY 20 2013
AS UPPER LOW GETS CLOSER TO THE AREA...SOME STRATUS AND CUMULUS
FIELD WRAPING BACK INTO THE AREA FROM BRIEF CLEARING...BUT MOST
CEILINGS VFR. WATCHING FOR ADDITIONAL CONVECTION THIS AFTERNOON BUT
STORM OCCULUSION AND SLIGHTLY DRIER AIR IN THE FORM OF LOWER CAPE
VALUES MAY KEEP STORMS SLIGHTLY WEAKER THAN YESTERDAY...IN ADDITION
TO A BIT MORE SOUTH AND EAST. WILL KEEP STORMS IN A VICINITY MODE
UNTIL MORE DETAIL CAN BE WORKED IN BUT THREAT SHOULD END BY
OVERNIGHT HOURS AS ANY CAPE DIMINISHES.
GENERALLY A VFR CEILING EXPECTED AS UPPER LOW SPINS AROUND THE AREA
FOR ANOTHER DAY OR TWO BUT SOME MVFR TIME IS POSSIBLE WITH LOWER
STRATUS FIELDS OR ROUNDS OF SHOWERS.
&&
.HYDROLOGY...
ISSUED AT 1235 PM CDT MON MAY 20 2013
AS HEAVIEST RAIN FOCUS SHIFTS A BIT SOUTH AND EAST OF HARDEST HIT
AREAS...CONFIDENCE IN ADDITIONAL FLOODING PROBLEMS HAD DROPPED
ENOUGH TO CLEAR SOME OF THE WATCH. BUT REMAINING HIGH WATER AND
RISING RIVERS PROMPTED KEEPING REST OF COUNTIES GOING IN WATCH AT
LEAST INTO LATE AFTERNOON.
SEEMS LIKE BEST MOISTURE TRANSPORT IS FOCUSING ON AREAS OF EASTERN
IOWA INTO SOUTHERN WISCONSIN...WHICH CAN HANDLE A BIT MORE RAIN. NO
CURRENT PLANS TO EXPAND ANY WATCHES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MNZ086-087-094-095.
IA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR IAZ008.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....SHEA
HYDROLOGY....AJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1019 AM CDT MON MAY 20 2013
.UPDATE...MAIN BAND OF CLOUDINESS IS SHIFTING EASTWARD THIS
MORNING...WHICH SHOULD ALLOW FOR A GOOD AMOUNT OF SUNSHINE INTO
THIS AFTERNOON. HIGH TEMPS WERE BUMPED UP A BIT OVERNIGHT AND
STILL SEEM REASONABLE.
BIGGEST CONCERN TODAY INTO TONIGHT IS TIMING AND STRENGTH OF
EXPECTED THUNDERSTORMS. SPC IS MAINTAINING A SLIGHT RISK FOR
SEVERE STORMS ACROSS THE FORECAST AREA FOR TODAY. LATEST NAM AND
RAP SOUNDINGS AGREE THAT THE ENVIRONMENT STILL LOOKS FAVORABLE FOR
STRONG TO SEVERE STORMS. WITH THE EXPECTED SUNSHINE...SHOULD SEE
SFC BASED CAPE GET IN THE 1000-1500 J/KG RANGE BY THIS AFTERNOON.
ADDITIONALLY...PLENTY OF 0-6 KM BULK SHEAR...GENERALLY 35-45 KT.
PLENTY OF MOISTURE AS WELL...WITH PRECIPITABLE WATER VALUES AROUND
1.25 INCHES...ABOVE CLIMATOLOGICAL NORMALS.
WITH A DECENT ENVIRONMENTAL SETUP...WILL JUST BE WAITING FOR THE
TRIGGER. LATEST WATER VAPOR INDICATING A SHORTWAVE TO THE
SOUTHWEST...WITH SOME ASSOCIATED CONVECTION OVER EASTERN KANSAS
AND WESTERN MISSOURI. TIMING OF THIS ACTIVITY TO THE SOUTHWEST
ALONG WITH LATEST HRRR AND LOCAL WRF4L MODEL INDICATE THE BEST
CHANCE FOR STORMS TO MOVE IN TODAY WILL BE IN THE DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS.
&&
.AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED TO CONTINUE
THROUGH TUESDAY...THOUGH LOWER CIGS/VSBYS POSSIBLE IN ANY
THUNDERSTORMS. BIG ISSUE THROUGH TOMORROW WILL BE TIMING ROUNDS OF
THUNDERSTORMS. LOOKS QUIET THIS MORNING...BUT WILL LIKELY SEE
STORMS DEVELOP THIS AFTERNOON OR EVENING...WITH STORMS THEN LIKELY
AT TIMES THROUGH TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 329 AM CDT MON MAY 20 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE - MEDIUM.
ATMOSPHERE HAS BEEN STABILIZED SOMEWHAT BY OVERNIGHT CONVECTION BUT
LIKELY TO TURN UNSTABLE ONCE AGAIN LATER THIS MORNING AND AFTERNOON
DUE TO RETURNING SUNSHINE AND LINGERING HIGHER RELATIVE HUMIDITY.
PRECIPITABLE WATER VALUES CONTINUE AROUND 1.5 INCHES. UPPER JET
CONTINUES TO PIVOT SLOWLY EWD INTO WI TODAY RESULTING IN SOME
ENHANCED UPWARD VERTICAL MOTION. DIFFICULT TO DISCERN INDIVIDUAL
SHORT WAVES ROTATING AROUND UPPER LOW OVER THE PLAINS BUT ALL SHORT
TERM GUIDANCE CONTINUES TO INDICATE WEAK WAVES ROTATING AROUND
PARENT LOW INTO THE REGION THROUGH TONIGHT. LOW LEVEL JET WEAKENS
THIS MRNG BUT STRENGTHENS AGAIN THIS AFTERNOON AND EVENING. HENCE
WL CONTINUE CHANCE/SCATTERED LEVEL POPS THROUGH TODAY...AND BEEF UP TO
LIKELY WORDING FOR TONIGHT. AGGREGATE SEVERE PARAMETER INDEX REMAINS
HIGH FOR POTENTIAL SEVERE WEATHER LATE THIS AFTERNOON AND EVENING.
TUESDAY - CONFIDENCE...MEDIUM
UPPER LOW CONTINUES TO SPIN TO OUR WEST ACRS SE SD/NE NEB/SW MN/NW
IA. SRN WI WILL REMAIN SITUATED IN A SOUTHWEST UPPER FLOW WITH
SHORTWAVES MOVING THROUGH. 850 THERMAL RIDGE SHIFTS EAST. SYSTEM
OCCLUDES...BUT ENOUGH COLD AIR UPSTAIRS AND LINGERING LOW LEVEL
INSTABILITY TO KEEP THUNDERSTORM POTENTIAL HIGH. GFS AND NAM
SOUNDINGS ARE NOT SHOWING TREMENDOUS CAPE. 850 JET AXIS PLACES SE WI
IN FAVORABLE LEFT FRONT QUAD REGION AND 250 MILLIBAR JET ACROSS WI.
SLIGHT RISK STILL LOOKS OK AT THIS POINT.
WEDNESDAY - CONFIDENCE...MEDIUM
500 MILLIBAR FINALLY PLODS ACROSS THE AREA. NAM AND GFS REALLY CRANK
OUT THE QPF WITH SECONDARY SURFACE LOW THAT STRENGTHENS A BIT FROM
NRN IL INTO LOWER MI. ALL MODELS SUGGEST ENHANCED LOWER LEVEL
CONVERGENCE WITH 850 LOW/TROUGH. 00Z CAME IN WITH HIGHER QPF AMOUNTS
IN SRN WI...AGREEING WITH THE 00Z OUTPUT FROM THE NAM AND GFS. 12Z
ECMWF HAD THE BETTER QPF ACRS NRN WI. MODELS SUGGEST A BIT OF
LINGERING UPPER JET ACTION ACRS ERN WI MAINLY IN THE MORNING.
THURSDAY - CONFIDENCE...MEDIUM
LINGERING LOW LEVEL TROUGH KEEPS SHRA CHANCES AROUND...THOUGH HIGH
GRADUALLY BUILDS IN WITH TIME. NNE 850 FLOW DEVELOPS WITH COOL POOL
SETTLING IN.
FRIDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE WILL DOMINATE. 12Z ECMWF SHOWS 3C AT 850 WHILE 00Z GFS
SHOWING 10C. EITHER WAY...LOOKING AT A QUIET DAY.
SATURDAY AND SUNDAY - CONFIDENCE...LOW
MODELS DIVERGING WITH TIMING/EVOLUTION OF WARM AIR ADVECTION/RIDGE
RIDER REGIME. BAROCLINIC ZONE POSITION IS IN QUESTION TOO. WILL LET
THE ALLBLEND POPS/TEMPS HANDLE THIS FOR NOW UNTIL MODELS COME INTO
BETTER AGREEMENT.
AVIATION/12Z TAFS/...POTENTIAL PERIOD OF LOW STRATUS IN WRN AREAS EARLY
THIS MRNG DUE TO BOUNDARY LAYER MIXING AND OVERNIGHT RAINFALL. OTHERWISE
EXPECT MOSTLY VFR CONDITIONS INTERRUPTED BY PASSING THUNDERSTORMS WITH
THE BEST CHANCE THIS AFTERNOON AND TONIGHT.
MARINE...WITH DEWPOINTS IN THE 60S LIKELY TO MOVE ACROSS THE NEARSHORE
WATERS...SOME PATCHY FOG AND HAZE LIKELY TO DEVELOP. COOLER WATERS
REMAIN TOWARD THE OPEN WATERS WITH SHALLOWER NEAR SHORE WATERS MORE
IN THE MIDDLE 50S TO AROUND 60. HENCE WL HOLD OFF ON INTRODUCING
DENSE FOG AT THIS TIME...BUT IS A CONCERN FARTHER AWAY FROM SHORE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...MBK
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
659 AM CDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT MON MAY 20 2013
MAIN FORECAST CONCERN IS ON SEVERE WEATHER AND FLOODING POTENTIAL
TODAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED AN UPPER LOW OVER SOUTH DAKOTA AND NEBRASKA WITH RIDGING
AHEAD OF IT OVER MICHIGAN. THE UPPER LOW WAS MOSTLY CUT OFF WITH
RIDGING TO ITS NORTH OVER SOUTH CENTRAL CANADA. 500MB STANDARD
DEVIATIONS WERE 1-1.5 BELOW NORMAL WITH THE UPPER LOW. NUMEROUS
SHORTWAVES WERE EJECTING IN SOUTHWEST FLOW AHEAD OF THE UPPER
LOW...SOME OF WHICH ARE CONVECTIVELY PRODUCED. ONE FOR EXAMPLE WAS
LIFTING THROUGH NORTHWEST WISCONSIN WHICH BROUGHT RAIN TO MUCH OF
THE AREA DURING THE NIGHTTIME HOURS. RAP DATA ALSO SHOWED A LOW
LEVEL MOISTURE TRANSPORT ZONE WITH THIS MCV. FARTHER SOUTH...ANOTHER
LOW LEVEL MOISTURE TRANSPORT ZONE WAS NOTED IN SOUTHERN MISSOURI...
POINTING INTO SOUTHERN ILLINOIS. COMBINATION OF SUBSIDENCE IN THE
WAKE OF THE MCV AND SPLIT IN MOISTURE TRANSPORT HAS ALLOWED THE
PRECIPITATION TO DIMINISH SOUTH OF HWY 29. PLENTIFUL MOISTURE COMING
UP AHEAD OF THE UPPER LOW WITH PRECIPITABLE WATER VALUES OF 1.2-1.5
INCHES FROM EASTERN OK INTO SOUTEHRN WI. THERE WAS A MINIMA OF
PRECIPITABLE WATER FROM WESTERN KS INTO MUCH OF IA...THOUGH....
ASSOCIATED WITH A DRY SLOT SOUTH OF THE UPPER LOW. AT THE
SURFACE...LOW PRESSURE WAS SITUATED UNDER THE UPPER LOW WITH A WARM
FRONT EXTENDING EAST TO EAU CLAIRE WI. RAP 850MB TEMPS WERE IN THE
14-18C RANGE SOUTH OF THE FRONT IN THE FORECAST AREA.
MODELS ARE IN GOOD AGREEMENT OF KEEPING THE UPPER LOW NEARLY
STATIONARY OVER SOUTH DAKOTA. DESPITE ITS STATIONARY MOVEMENT...THE
WEATHER WILL BE QUITE A BIT DIFFERENT COMPARED TO YESTERDAY.
PRIMARILY THIS IS DUE TO THE UPPER FLOW AHEAD OF THE UPPER LOW
PROGGED MORE SOUTHWESTERLY VERSUS SOUTHERLY. ADDITIONALLY...THE
PLUME OF HIGHER PRECIPITABLE WATER IS PROGGED TO SLOWLY SHIFT EAST
THANKS TO THE UPPER LOW.
MOST OF THE FORECAST AREA IS INDICATED TO STAY IN THE WARM SECTOR
THROUGH TONIGHT...ALONG WITH EXISTING IN THAT SOUTHWEST FLOW FOR
SHORTWAVES TO COME THROUGH...BOTH FAVORABLE FOR THUNDERSTORM
DEVELOPMENT. HOWEVER...ONE QUESTION MARK IS MOISTURE. BASED ON A
AMDAR SOUNDING OUT OF OMAHA AT 04Z...THE 850MB DEWPOINTS FROM THE
20.00Z NAM WERE 6-7C TOO HIGH...THUS THE NAM BUILDS A LOT OF CAPE
QUICKLY THIS MORNING. THE RAP IS MUCH MORE SUBDUED HAVING THE AREA
ENCOMPASSED BY THE DRY AIR...ESPECIALLY WHEN LOOKING AT MLCAPE.
THINKING THE RAP IDEA IS MUCH MORE REPRESENTATIVE AND HAVE KEPT THE
AREA DRY THROUGH EARLY AFTERNOON. EVENTUALLY...THE RAP DOES CATCH UP
WITH THE CAPE LATE IN THE AFTERNOON THANKS TO EVAPOTRANSPORATION OF
MOIST SOILS. IN FACT...THE RAP SHOWS A DEFINITIVE DRY LINE IN THE
WARM SECTOR FORMING NEAR I-35 IN THE AFTERNOON. THIS DRY LINE SHOULD
SERVE AS A TRIGGER FOR CONVECTIVE DEVELOPMENT...ESPECIALLY IN
SOUTHEAST MN AND NORTHEAST IA. MAJORITY OF MODELS...INCLUDING HI
RESOLUTION ONES...SHOW THIS SCENARIO...WITH THE THUNDERSTORMS THEN
PROPAGATING NORTHEAST THROUGH THE EVENING. THE BEST 0-6KM SHEAR OF
GREATER THAN 35 KTS IS PROGGED OVER THE SOUTHEAST HALF OF THE
FORECAST AREA...OPPOSITE OF WHERE MOST OF THE CONVECTION WILL BE. ON
THE OTHER HAND...FREEZING LEVEL HEIGHTS ARE LOWER ON THE ORDER OF
10500 FT WHERE THE CONVECTION IS EXPECTED...THUS THERE COULD END UP
BEING MARGINALLY SEVERE HAIL. STORMS SHOULD GRADUALLY WEAKEN AS
INSTABILITY WANES LATE IN THE EVENING INTO THE OVERNIGHT HOURS. IT
SHOULD BE NOTED...IF FOR SOME REASON A STORM FIRES IN THE HIGHER
0-6KM SHEAR AREA THIS AFTERNOON...IT WOULD LIKELY BECOME
SUPERCELLULAR. AGAIN...THOUGH...THINK THIS IS A LOW PROBABILITY WITH
THAT AREA PERHAPS EVEN BEING CAPPED. SEE THE HYDROLOGY SECTION BELOW
FOR FLOODING CONCERNS.
CERTAINTLY THE ADDITIONAL RAIN FROM STORMS THIS AFTERNOON AND EARLY
EVENING WILL NOT HELP THE FLOODING MATTERS IN PORTIONS OF SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. HAVE KEPT THE FLASH FLOOD WATCH GOING
TO 00Z THIS EVENING...WHICH WORKS OUT WELL IN TERMS OF TIME BECAUSE
THE CONVECTION SHOULD MOSTLY BE EAST OF THERE BY THE EXPIRATION.
SHOULD SEE QUITE A BIT OF SUN TODAY AND WITH 850MB TEMPS HOVERING IN
THAT 14-18C RANGE...TEMPERATURES SHOULD EASILY CLIMB INTO THE UPPER
70S TO MID 80S. ANOTHER MILD NIGHT LIKELY TONIGHT WITH PLENTY OF
CLOUDS AND DEWPOINTS REMAINING UP IN THE 50S TO LOW 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 341 AM CDT MON MAY 20 2013
TUESDAY THROUGH THURSDAY...
MAIN FOCUS HERE IS ON THE EVOLUTION OF THE UPPER LOW. 20.00Z
ECMWF/GFS/CANADIAN/NAM ARE ALL IN PRETTY GOOD AGREEMENT HOLDING THE
UPPER LOW NEARLY STATIONARY ON TUESDAY...THEN GRADUALLY SHIFTING
EASTWARD TUESDAY NIGHT AND WEDNESDAY BEFORE IT GETS MORE OF A KICK
EAST WEDNESDAY NIGHT. THE KICK EAST IS IN RESPONSE TO A POTENT
TROUGH DROPPING SOUTH THROUGH MUCH OF EASTERN CANADA.
FOR TUESDAY...MUCH OF THE FORECAST AREA WEST OF THE MISSISSIPPI
RIVER LOOKS TO BE DRY-SLOTTED...THUS HAVE LOWERED PRECIPITATION
CHANCES. TO THE EAST...THERE ARE INDICATIONS THAT SOME DIURNAL
CONVECTION COULD FORM ALONG A COLD FRONT MARCHING EAST. INSTABILITY
IS PRETTY MEAGER IN THIS CASE COMPARED TO WHAT WE HAVE BEEN DEALING
WITH...THUS ANY CONVECTION SHOULD NOT GO SEVERE. BETTER SHOT FOR
SEVERE WEATHER WILL BE WELL SOUTH AND EAST OF THE FORECAST AREA.
HIGHEST PRECIPITATION CHANCES OVERALL ARE EXPECTED NORTH OF HWY 29
IN A LOW TO MID LEVEL FRONTOGENESIS ZONE.
AS THE UPPER LOW BEGINS TO PUSH EAST TOWARDS THE FORECAST AREA
TUESDAY NIGHT AND WEDNESDAY...DPVA INCREASES WHILE SIMULTANEOUSLY
THE LOW TO MID LEVEL FRONTOGENESIS ZONE DROPS SOUTH. THEREFORE...
INCREASING PRECIPITATION CHANCES SEEM REASONABLE... ESPECIALLY ON
WEDNESDAY WHEN THE TWO FORCING MECHANISMS ARE JUXTAPOSTED.
ADDITIONALLY...THERE COULD BE SOME DIURNAL ENHANCEMENT ON WEDNESDAY
BEING CLOSE TO OR UNDER THE COLD CORE OF THE UPPER LOW.
MODELS APPEAR TO BE TRENDING FASTER IN KICKING OUT THE UPPER LOW FOR
WEDNESDAY NIGHT AND THURSDAY...ENOUGH SO THAT THURSDAY MAY NOW END
UP DRY. WEDNESDAY NIGHT STILL LOOKS FAVORABLE FOR PRECIPITATION...
ESPECIALLY EAST OF THE MISSISSIPPI RIVER WHICH IS IN THAT
AFOREMENTIONED JUXTAPOSITION OF FORCING MECHANISMS.
DEFINITELY A COOLING TREND WILL TAKE PLACE FOR TUESDAY THROUGH
THURSDAY WITH THAT UPPER LOW COMING IN...AND THEN COME THURSDAY A
NORTHERLY FLOW ADVECTING AIR FROM CANADIAN HIGH PRESSURE TRYING TO
BUILD SOUTH INTO THE UPPER GREAT LAKES. 850MB TEMPS FALL FROM 11-13C
AT 12Z TUE TO 4-6C BY 12Z THU. WENT WITH A BLEND OF GUIDANCE FOR
HIGHS AND LOWS FOR NOW GIVEN NO SIGNAL TO LEAN TOWARDS WARMER OR
COLDER SCENARIO GIVEN THE FORECAST PATTERN.
THURSDAY NIGHT INTO NEXT WEEKEND...
20.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO ADVERTISE A
BLOCKED UP UPPER LEVEL FLOW PATTERN ACROSS NORTH AMERICA DURING THE
EXTENDED PORTION OF THE FORECAST. THE FLOW FEATURES DEEP TROUGHING
ALONG THE WEST COAST...RIDGING FROM THE PLAINS INTO THE NORTHWEST
TERRITORIES...AND MEAN TROUGHING FROM EASTERN CANADA INTO THE
MID-ATLANTIC REGION. WHAT THIS PATTERN MEANS FOR THE FORECAST AREA
IS A BATTLE BETWEEN DRY...CANADIAN HIGH PRESSURE AND A MORE HUMID
AIRMASS ADVECTING NORTH OUT OF THE GULF OF MEXICO UNDER THE UPPER
RIDGE. IT APPEARS DRY CONDITIONS SHOULD PREVAIL FOR THURSDAY NIGHT
AND FRIDAY...RESULTING FROM SUBSIDENCE IN THE WAKE OF THE EARLY TO
MID WEEK UPPER LOW. FROM FRIDAY NIGHT AND BEYOND...HAVE FOLLOWED A
CONSENSUS APPROACH AND SPREAD PRECIPITATION CHANCES ACROSS THE
FORECAST AREA...HIGHEST WEST OF THE MISSISSIPPI RIVER. THESE CHANCES
ARE A RESULT OF SURGES OF WARM ADVECTION. THE PRECIPITATION COULD
BECOME ENHANCED TOO AT TIMES AS JET STREAKS PROPAGATE BETWEEN THE
EASTERN CANADA TROUGH AND PLAINS RIDGING.
SOMETHING TO WATCH DURING THE EXTENDED IS POTENTIAL FOR FROST...
ESPECIALLY IN CENTRAL WISCONSIN. THURSDAY NIGHT ACCORDING TO 20.00Z
MODELS WOULD BE THE HIGHEST CHANCE...THOUGH CONFIDENCE IS NOT HIGH
ENOUGH TO EITHER MENTION FROST IN THE FORECAST OR DROP LOWS BELOW
40. OTHERWISE...TEMPERATURES SHOULD STAY MOSTLY BELOW NORMAL BEING
UNDER THE INFLUENCE OF THE CANADIAN HIGH AND A NORTHEAST FLOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 658 AM CDT MON MAY 20 2013
THE MVFR CEILINGS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA WILL
GRADUALLY MIX OUT THIS MORNING. THIS SHOULD OCCUR AT KRST AROUND
20.15Z.
STEEP LOW LEVEL LAPSE RATES WILL KEEP WIND GUSTS IN THE 20 TO 30
KNOT RANGE THROUGHOUT THE DAY.
FOR THIS AFTERNOON AND EVENING...A TROUGH...LOCATED OVER KANSAS...WILL
MOVE NORTHEAST THROUGH THE AREA. AS THIS OCCURS...EXPECTY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA BETWEEN
20.21Z AND 21.00Z. THE 0-3KM WINDS ARE FAVORABLE FOR THE THUNDERSTORMS
TO PRODUCE DAMAGING WINDS. IN ADDITION...THERE WILL BE ENOUGH
INSTABILITY FOR LARGE HAIL.
AS THE TROUGH MOVES NORTHEAST OF THE AREA AFTER 21.06Z...EXPECT A
BROKEN DECK OF 8-10K CEILING TO LINGER ACROSS THE AREA THROUGH THE
REMAINDER OF THE NIGHT.
&&
.HYDROLOGY...
ISSUED AT 341 AM CDT MON MAY 20 2013
MULTIPLE DAYS OF HEAVY RAIN ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA HAS REALLY LOWERED THE THRESHOLD FOR FLOODING. A
STRIPE FROM MITCHELL COUNTY IA THROUGH MOWER...WESTERN FILLMORE AND
OLMSTED COUNTIES WERE ESPECIALLY HARD HIT FROM YESTERDAYS RAIN.
REPORT FROM MITCHELL COUNTY IA EMERGENCY MANAGER AT 330 AM WAS THAT
MOST MAIN ROADS ARE CLOSED DUE TO HIGH WATER AND MANY SIDE ROADS ARE
WASHED OUT. THUS...THE AREA THAT WAS PUT IN A FLASH FLOOD WATCH
YESTERDAY CANNOT HANDLE ANY MORE RAIN. SEE LATEST AREAL AND RIVER
FLOOD STATEMENTS FOR MORE INFORMATION.
ON A POSITIVE NOTE...THE DEEP MOISTURE THAT WAS PRESENT TO ALLOW THE
STORMS TO PRODUCE SUCH HEAVY RAIN IS SHIFTING OFF TO THE EAST.
ADDITIONALLY...EVEN THOUGH SOME THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON...THERE LOOKS TO BE ENOUGH UPPER LEVEL FLOW TO KEEP THEM
MOVING TO THE EAST. THUS...NOT ANTICIPATING ANY WIDESPREAD FLOODING.
WILL NEED TO KEEP THE FLASH FLOOD WATCH GOING...THOUGH...BECAUSE AS
MENTIONED EARLIER THE AREA HAS BEEN SO HARD HIT ANY RAIN WILL CAUSE
A PROBLEM.
ADDITIONAL RAINFALL IS POSSIBLE TUESDAY THROUGH WEDNESDAY
NIGHT...THOUGH TUESDAY IS TRENDING DRIER FOR SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. HOPEFULLY THE DRIER PERIOD FROM TONIGHT THROUGH
TUESDAY WILL ALLOW THE FLOOD THREAT TO DIMINISH...THOUGH RIVER
FLOODING MAY TAKE A LITTLE LONGER TO END.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MNZ079-086-087-094-
095.
IA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR IAZ008.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 AM CDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT MON MAY 20 2013
MAIN FORECAST CONCERN IS ON SEVERE WEATHER AND FLOODING POTENTIAL
TODAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED AN UPPER LOW OVER SOUTH DAKOTA AND NEBRASKA WITH RIDGING
AHEAD OF IT OVER MICHIGAN. THE UPPER LOW WAS MOSTLY CUT OFF WITH
RIDGING TO ITS NORTH OVER SOUTH CENTRAL CANADA. 500MB STANDARD
DEVIATIONS WERE 1-1.5 BELOW NORMAL WITH THE UPPER LOW. NUMEROUS
SHORTWAVES WERE EJECTING IN SOUTHWEST FLOW AHEAD OF THE UPPER
LOW...SOME OF WHICH ARE CONVECTIVELY PRODUCED. ONE FOR EXAMPLE WAS
LIFTING THROUGH NORTHWEST WISCONSIN WHICH BROUGHT RAIN TO MUCH OF
THE AREA DURING THE NIGHTTIME HOURS. RAP DATA ALSO SHOWED A LOW
LEVEL MOISTURE TRANSPORT ZONE WITH THIS MCV. FARTHER SOUTH...ANOTHER
LOW LEVEL MOISTURE TRANSPORT ZONE WAS NOTED IN SOUTHERN MISSOURI...
POINTING INTO SOUTHERN ILLINOIS. COMBINATION OF SUBSIDENCE IN THE
WAKE OF THE MCV AND SPLIT IN MOISTURE TRANSPORT HAS ALLOWED THE
PRECIPITATION TO DIMINISH SOUTH OF HWY 29. PLENTIFUL MOISTURE COMING
UP AHEAD OF THE UPPER LOW WITH PRECIPITABLE WATER VALUES OF 1.2-1.5
INCHES FROM EASTERN OK INTO SOUTEHRN WI. THERE WAS A MINIMA OF
PRECIPITABLE WATER FROM WESTERN KS INTO MUCH OF IA...THOUGH....
ASSOCIATED WITH A DRY SLOT SOUTH OF THE UPPER LOW. AT THE
SURFACE...LOW PRESSURE WAS SITUATED UNDER THE UPPER LOW WITH A WARM
FRONT EXTENDING EAST TO EAU CLAIRE WI. RAP 850MB TEMPS WERE IN THE
14-18C RANGE SOUTH OF THE FRONT IN THE FORECAST AREA.
MODELS ARE IN GOOD AGREEMENT OF KEEPING THE UPPER LOW NEARLY
STATIONARY OVER SOUTH DAKOTA. DESPITE ITS STATIONARY MOVEMENT...THE
WEATHER WILL BE QUITE A BIT DIFFERENT COMPARED TO YESTERDAY.
PRIMARILY THIS IS DUE TO THE UPPER FLOW AHEAD OF THE UPPER LOW
PROGGED MORE SOUTHWESTERLY VERSUS SOUTHERLY. ADDITIONALLY...THE
PLUME OF HIGHER PRECIPITABLE WATER IS PROGGED TO SLOWLY SHIFT EAST
THANKS TO THE UPPER LOW.
MOST OF THE FORECAST AREA IS INDICATED TO STAY IN THE WARM SECTOR
THROUGH TONIGHT...ALONG WITH EXISTING IN THAT SOUTHWEST FLOW FOR
SHORTWAVES TO COME THROUGH...BOTH FAVORABLE FOR THUNDERSTORM
DEVELOPMENT. HOWEVER...ONE QUESTION MARK IS MOISTURE. BASED ON A
AMDAR SOUNDING OUT OF OMAHA AT 04Z...THE 850MB DEWPOINTS FROM THE
20.00Z NAM WERE 6-7C TOO HIGH...THUS THE NAM BUILDS A LOT OF CAPE
QUICKLY THIS MORNING. THE RAP IS MUCH MORE SUBDUED HAVING THE AREA
ENCOMPASSED BY THE DRY AIR...ESPECIALLY WHEN LOOKING AT MLCAPE.
THINKING THE RAP IDEA IS MUCH MORE REPRESENTATIVE AND HAVE KEPT THE
AREA DRY THROUGH EARLY AFTERNOON. EVENTUALLY...THE RAP DOES CATCH UP
WITH THE CAPE LATE IN THE AFTERNOON THANKS TO EVAPOTRANSPORATION OF
MOIST SOILS. IN FACT...THE RAP SHOWS A DEFINITIVE DRY LINE IN THE
WARM SECTOR FORMING NEAR I-35 IN THE AFTERNOON. THIS DRY LINE SHOULD
SERVE AS A TRIGGER FOR CONVECTIVE DEVELOPMENT...ESPECIALLY IN
SOUTHEAST MN AND NORTHEAST IA. MAJORITY OF MODELS...INCLUDING HI
RESOLUTION ONES...SHOW THIS SCENARIO...WITH THE THUNDERSTORMS THEN
PROPAGATING NORTHEAST THROUGH THE EVENING. THE BEST 0-6KM SHEAR OF
GREATER THAN 35 KTS IS PROGGED OVER THE SOUTHEAST HALF OF THE
FORECAST AREA...OPPOSITE OF WHERE MOST OF THE CONVECTION WILL BE. ON
THE OTHER HAND...FREEZING LEVEL HEIGHTS ARE LOWER ON THE ORDER OF
10500 FT WHERE THE CONVECTION IS EXPECTED...THUS THERE COULD END UP
BEING MARGINALLY SEVERE HAIL. STORMS SHOULD GRADUALLY WEAKEN AS
INSTABILITY WANES LATE IN THE EVENING INTO THE OVERNIGHT HOURS. IT
SHOULD BE NOTED...IF FOR SOME REASON A STORM FIRES IN THE HIGHER
0-6KM SHEAR AREA THIS AFTERNOON...IT WOULD LIKELY BECOME
SUPERCELLULAR. AGAIN...THOUGH...THINK THIS IS A LOW PROBABILITY WITH
THAT AREA PERHAPS EVEN BEING CAPPED. SEE THE HYDROLOGY SECTION BELOW
FOR FLOODING CONCERNS.
CERTAINTLY THE ADDITIONAL RAIN FROM STORMS THIS AFTERNOON AND EARLY
EVENING WILL NOT HELP THE FLOODING MATTERS IN PORTIONS OF SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. HAVE KEPT THE FLASH FLOOD WATCH GOING
TO 00Z THIS EVENING...WHICH WORKS OUT WELL IN TERMS OF TIME BECAUSE
THE CONVECTION SHOULD MOSTLY BE EAST OF THERE BY THE EXPIRATION.
SHOULD SEE QUITE A BIT OF SUN TODAY AND WITH 850MB TEMPS HOVERING IN
THAT 14-18C RANGE...TEMPERATURES SHOULD EASILY CLIMB INTO THE UPPER
70S TO MID 80S. ANOTHER MILD NIGHT LIKELY TONIGHT WITH PLENTY OF
CLOUDS AND DEWPOINTS REMAINING UP IN THE 50S TO LOW 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 341 AM CDT MON MAY 20 2013
TUESDAY THROUGH THURSDAY...
MAIN FOCUS HERE IS ON THE EVOLUTION OF THE UPPER LOW. 20.00Z
ECMWF/GFS/CANADIAN/NAM ARE ALL IN PRETTY GOOD AGREEMENT HOLDING THE
UPPER LOW NEARLY STATIONARY ON TUESDAY...THEN GRADUALLY SHIFTING
EASTWARD TUESDAY NIGHT AND WEDNESDAY BEFORE IT GETS MORE OF A KICK
EAST WEDNESDAY NIGHT. THE KICK EAST IS IN RESPONSE TO A POTENT
TROUGH DROPPING SOUTH THROUGH MUCH OF EASTERN CANADA.
FOR TUESDAY...MUCH OF THE FORECAST AREA WEST OF THE MISSISSIPPI
RIVER LOOKS TO BE DRY-SLOTTED...THUS HAVE LOWERED PRECIPITATION
CHANCES. TO THE EAST...THERE ARE INDICATIONS THAT SOME DIURNAL
CONVECTION COULD FORM ALONG A COLD FRONT MARCHING EAST. INSTABILITY
IS PRETTY MEAGER IN THIS CASE COMPARED TO WHAT WE HAVE BEEN DEALING
WITH...THUS ANY CONVECTION SHOULD NOT GO SEVERE. BETTER SHOT FOR
SEVERE WEATHER WILL BE WELL SOUTH AND EAST OF THE FORECAST AREA.
HIGHEST PRECIPITATION CHANCES OVERALL ARE EXPECTED NORTH OF HWY 29
IN A LOW TO MID LEVEL FRONTOGENESIS ZONE.
AS THE UPPER LOW BEGINS TO PUSH EAST TOWARDS THE FORECAST AREA
TUESDAY NIGHT AND WEDNESDAY...DPVA INCREASES WHILE SIMULTANEOUSLY
THE LOW TO MID LEVEL FRONTOGENESIS ZONE DROPS SOUTH. THEREFORE...
INCREASING PRECIPITATION CHANCES SEEM REASONABLE... ESPECIALLY ON
WEDNESDAY WHEN THE TWO FORCING MECHANISMS ARE JUXTAPOSTED.
ADDITIONALLY...THERE COULD BE SOME DIURNAL ENHANCEMENT ON WEDNESDAY
BEING CLOSE TO OR UNDER THE COLD CORE OF THE UPPER LOW.
MODELS APPEAR TO BE TRENDING FASTER IN KICKING OUT THE UPPER LOW FOR
WEDNESDAY NIGHT AND THURSDAY...ENOUGH SO THAT THURSDAY MAY NOW END
UP DRY. WEDNESDAY NIGHT STILL LOOKS FAVORABLE FOR PRECIPITATION...
ESPECIALLY EAST OF THE MISSISSIPPI RIVER WHICH IS IN THAT
AFOREMENTIONED JUXTAPOSITION OF FORCING MECHANISMS.
DEFINITELY A COOLING TREND WILL TAKE PLACE FOR TUESDAY THROUGH
THURSDAY WITH THAT UPPER LOW COMING IN...AND THEN COME THURSDAY A
NORTHERLY FLOW ADVECTING AIR FROM CANADIAN HIGH PRESSURE TRYING TO
BUILD SOUTH INTO THE UPPER GREAT LAKES. 850MB TEMPS FALL FROM 11-13C
AT 12Z TUE TO 4-6C BY 12Z THU. WENT WITH A BLEND OF GUIDANCE FOR
HIGHS AND LOWS FOR NOW GIVEN NO SIGNAL TO LEAN TOWARDS WARMER OR
COLDER SCENARIO GIVEN THE FORECAST PATTERN.
THURSDAY NIGHT INTO NEXT WEEKEND...
20.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES CONTINUE TO ADVERTISE A
BLOCKED UP UPPER LEVEL FLOW PATTERN ACROSS NORTH AMERICA DURING THE
EXTENDED PORTION OF THE FORECAST. THE FLOW FEATURES DEEP TROUGHING
ALONG THE WEST COAST...RIDGING FROM THE PLAINS INTO THE NORTHWEST
TERRITORIES...AND MEAN TROUGHING FROM EASTERN CANADA INTO THE
MID-ATLANTIC REGION. WHAT THIS PATTERN MEANS FOR THE FORECAST AREA
IS A BATTLE BETWEEN DRY...CANADIAN HIGH PRESSURE AND A MORE HUMID
AIRMASS ADVECTING NORTH OUT OF THE GULF OF MEXICO UNDER THE UPPER
RIDGE. IT APPEARS DRY CONDITIONS SHOULD PREVAIL FOR THURSDAY NIGHT
AND FRIDAY...RESULTING FROM SUBSIDENCE IN THE WAKE OF THE EARLY TO
MID WEEK UPPER LOW. FROM FRIDAY NIGHT AND BEYOND...HAVE FOLLOWED A
CONSENSUS APPROACH AND SPREAD PRECIPITATION CHANCES ACROSS THE
FORECAST AREA...HIGHEST WEST OF THE MISSISSIPPI RIVER. THESE CHANCES
ARE A RESULT OF SURGES OF WARM ADVECTION. THE PRECIPITATION COULD
BECOME ENHANCED TOO AT TIMES AS JET STREAKS PROPAGATE BETWEEN THE
EASTERN CANADA TROUGH AND PLAINS RIDGING.
SOMETHING TO WATCH DURING THE EXTENDED IS POTENTIAL FOR FROST...
ESPECIALLY IN CENTRAL WISCONSIN. THURSDAY NIGHT ACCORDING TO 20.00Z
MODELS WOULD BE THE HIGHEST CHANCE...THOUGH CONFIDENCE IS NOT HIGH
ENOUGH TO EITHER MENTION FROST IN THE FORECAST OR DROP LOWS BELOW
40. OTHERWISE...TEMPERATURES SHOULD STAY MOSTLY BELOW NORMAL BEING
UNDER THE INFLUENCE OF THE CANADIAN HIGH AND A NORTHEAST FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 115 AM CDT MON MAY 20 2013
IT APPEARS THE LAST SURGE OF RAIN AND THUNDERSTORMS ARE MOVING
NORTH THROUGH THE TAF SITES AT THIS TIME AND FOR THE NEXT FEW
HOURS. MODERATE RAIN AND MVFR CIGS/VSBYS WILL CLEAR AS THE RAIN
MOVES OFF TO THE NORTH. A CLEARING TREND IS EXPECTED WITH VFR
EXPECTED FOR THE DAYLIGHT HOURS.
INSTABILITY WILL AGAIN BUILD OVER THE TAF SITES AND SET THE STAGE
FOR LATE AFTERNOON AND EVENING TSRA CHANCES. FOR NOW HAVE INCLUDED
A VCTS AND FUTURE FORECASTS CAN REFINE THE TIMING AT THE TAF
SITES. MONDAY AFTERNOON AND EVENING TSRA COVERAGE IS NOT EXPECTED
TO BE AS WIDESPREAD OR AFFECT THE TAF SITES AS LONG AS THE
ACTIVITY SUNDAY NIGHT.
&&
.HYDROLOGY...
ISSUED AT 341 AM CDT MON MAY 20 2013
MULTIPLE DAYS OF HEAVY RAIN ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA HAS REALLY LOWERED THE THRESHOLD FOR FLOODING. A
STRIPE FROM MITCHELL COUNTY IA THROUGH MOWER...WESTERN FILLMORE AND
OLMSTED COUNTIES WERE ESPECIALLY HARD HIT FROM YESTERDAYS RAIN.
REPORT FROM MITCHELL COUNTY IA EMERGENCY MANAGER AT 330 AM WAS THAT
MOST MAIN ROADS ARE CLOSED DUE TO HIGH WATER AND MANY SIDE ROADS ARE
WASHED OUT. THUS...THE AREA THAT WAS PUT IN A FLASH FLOOD WATCH
YESTERDAY CANNOT HANDLE ANY MORE RAIN. SEE LATEST AREAL AND RIVER
FLOOD STATEMENTS FOR MORE INFORMATION.
ON A POSITIVE NOTE...THE DEEP MOISTURE THAT WAS PRESENT TO ALLOW THE
STORMS TO PRODUCE SUCH HEAVY RAIN IS SHIFTING OFF TO THE EAST.
ADDITIONALLY...EVEN THOUGH SOME THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON...THERE LOOKS TO BE ENOUGH UPPER LEVEL FLOW TO KEEP THEM
MOVING TO THE EAST. THUS...NOT ANTICIPATING ANY WIDESPREAD FLOODING.
WILL NEED TO KEEP THE FLASH FLOOD WATCH GOING...THOUGH...BECAUSE AS
MENTIONED EARLIER THE AREA HAS BEEN SO HARD HIT ANY RAIN WILL CAUSE
A PROBLEM.
ADDITIONAL RAINFALL IS POSSIBLE TUESDAY THROUGH WEDNESDAY
NIGHT...THOUGH TUESDAY IS TRENDING DRIER FOR SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. HOPEFULLY THE DRIER PERIOD FROM TONIGHT THROUGH
TUESDAY WILL ALLOW THE FLOOD THREAT TO DIMINISH...THOUGH RIVER
FLOODING MAY TAKE A LITTLE LONGER TO END.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MNZ079-086-087-094-
095.
IA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR IAZ008.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BAUMGARDT
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
111 AM CDT MON MAY 20 2013
.SHORT TERM...(TONIGHT AND MONDAY)
ISSUED AT 220 PM CDT SUN MAY 19 2013
UPPER LEVEL SHORTWAVE TROUGH SERVING AS ONE FOCUS FOR STORM
DEVELOPMENT EARLY THIS AFTERNOON. SKIES HAVE CLEARED AHEAD OF THE
SHORTWAVE...MOVING NORTH/NORTHEAST ACROSS IOWA...ALLOWING FOR RAPID
DESTABILIZATION OF THE ATMOSPHERE. MUCAPES PER LATEST RAP ANALYSIS
HAVE RISEN INTO THE 2-3 K J/KG RANGE...WITH 30-40 KTS OF EFFECTIVE
SHEAR. SUPERCELL DEVELOPMENT IS SUPPORTED. SEE A POTENTIAL FOR ALL
SEVERE WEATHER TYPES...WITH SUPERCELLS MORPHING INTO BOWING
SEGMENTS. THINK DAMAGING WINDS MIGHT BECOME THE GREATER THREAT LATER
THIS AFTERNOON AND EVENING.
HRRR SUGGESTS THERE WILL BE ANOTHER ROUND OF STRONG/SEVERE STORMS
COMING IN TOWARD 06S AS A SHORTWAVE PUSHES NORTHWARD ACROSS IOWA.
INSTABILITY WOULD DECREASE WITH THE LOSS OF DAYTIME HEATING...BUT
GFS/NAM STILL SUGGEST 1000+ J/KG OF MUCAPE AT 06Z...WITH 40+ KTS OF
0-6 KM SHEAR. PLENTY TO CONTINUE A SEVERE THREAT.
FOR MONDAY...ATMOSPHERE PROGGED TO RELOAD FOR THE AFTERNOON/EVENING
WITH MUCAPES UPWARDS OF 2500 J/KG AND MLCAPES UP TO 2000 J/KG. 0-6KM
WIND SHEAR CLIMBS TO 40-50 KTS BY 00Z TUE...SUPPORTIVE OF SUPERCELL
DEVELOPMENT. 0-1KM SHEAR IS 15-20 KTS. IF ALL THIS COMES TO
PASS...ATMOSPHERE WOULD BE RIPE FOR SEVERE WEATHER...WITH ROTATING
SUPERCELLS AND THE GAMBIT OF SEVERE THREATS. THE KEY IS THE
KICKER...AND THAT IS WHERE THE FORECAST CHALLENGE LIES. GFS/NAM
SUGGEST A SHORTWAVE TROUGH COULD LIFT OUT OF THE BASE OF THE UPPER
LEVEL TROUGH FOR THE AFTERNOON/EVENING...BUT ALSO POINT TO POSSIBLE
MCVS SPINNING INTO THE REGION. MEANWHILE...THERE WILL LIKELY BE LEFT
OVER SFC BOUNDARIES FROM CONVECTION TODAY/TONIGHT. WHERE THESE LIE
IS UNKNOWN. CONFIDENCE IS NOT HIGH IN WHERE/WHEN CONVECTION WILL
FIRE...BUT BELIEVE THE LATE AFTERNOON/EVENING WOULD BE THE FAVORED
TIME FOR A SEVERE THREAT...AND GENERALLY FROM CENTRAL WI INTO
NORTHEAST IA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 220 PM CDT SUN MAY 19 2013
THE VIRTUALLY STATIONARY UPPER LEVEL LOW FINALLY STARTS TO MAKE ITS
WAY EAST OUT OF THE NORTHERN PLAINS TUE...PER LATEST GFS/NAM/EC. THE
LOW WEAKENS SOME AS IT SLIDES OVER THE UPPER MISSISSIPPI RIVER
VALLEY TUE NIGHT/WED. MAIN COLD FRONT WITH THIS SYSTEM LOOKS LIKE IT
WILL SLIP THROUGH WITH THE LOW AROUND WED...BUT MODELS KEEP
CONVECTION AT A MINIMUM AROUND IT. RATHER...THE PCPN FOCUS IS
WITH THE LOW LEVEL MOISTURE TRANSPORT...WHICH IS WELL EAST OF THE
COLD FRONT...WRAPPING NORTH/WEST OF THE LOW. SOME MODEL DISAGREEMENT
WITH HOW FAR SOUTH THE AREAS OF SHOWERS/ISOLD STORMS WOULD REACH
WED...WITH THE GFS MORE SOUTH THAN THE EC. IT REMAINS A MESSY
SCENARIO WITH CLARITY LACKING...BUT TRENDS FAVOR THE GREATER PCPN
CHANCES OVER THE NORTHERN 1/2 OF THE FORECAST AREA. WILL LEAN ON
MODEL CONSENSUS FOR THE CHANCES.
TURNING BACK TO TUE...MUCAPES BUILD TO 1500+ J/KG OVER THE EASTERN
1/2 OF THE FORECAST DURING THE AFTERNOON...WITH 0-6 KM SHEAR OF
30-40 KTS. SOME SUGGESTIONS IN THE GFS/NAM OF A PIECE OF UPPER LEVEL
ENERGY ROTATING AROUND THE LOW...WHICH COULD SERVE AS A FOCUS FOR
SHOWER/STORM DEVELOPMENT. ATMOSPHERE LOOKS GOOD FOR STORM PRODUCTION
IF A SPARK FOR CONVECTION IS THERE...WITH A SEVERE THREAT IN THE
EAST TUE AFTERNOON/EARLY EVENING. AGAIN...KEY HERE IS WHERE THE PCPN
FOCUSES WILL BE...INCLUDING ANY MESO SCALE BOUNDARIES AND/OR MCVS
LEFT FROM PREVIOUS CONVECTION.
BETTER AGREEMENT BETWEEN THE GFS AND ECMWF WITH PUSHING THAT
LINGERING LOW EAST/SOUTHEAST ON THU...ALLOWING AN UPPER LEVEL SFC
RIDGE/HIGH PRESSURE SYSTEM TO BUILD INTO THE REGION. SHOULD GET A
COUPLE DRIER DAYS AS A RESULT. HOWEVER...WARM/MOIST AIR ON THE
BACKSIDE OF THE HIGH COUPLED WITH A BIT OF UPPER LEVEL ENERGY COULD
RETURN SOME SHOWERS/STORMS TO THE REGION SAT-SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 115 AM CDT MON MAY 20 2013
IT APPEARS THE LAST SURGE OF RAIN AND THUNDERSTORMS ARE MOVING
NORTH THROUGH THE TAF SITES AT THIS TIME AND FOR THE NEXT FEW
HOURS. MODERATE RAIN AND MVFR CIGS/VSBYS WILL CLEAR AS THE RAIN
MOVES OFF TO THE NORTH. A CLEARING TREND IS EXPECTED WITH VFR
EXPECTED FOR THE DAYLIGHT HOURS.
INSTABILITY WILL AGAIN BUILD OVER THE TAF SITES AND SET THE STAGE
FOR LATE AFTERNOON AND EVENING TSRA CHANCES. FOR NOW HAVE INCLUDED
A VCTS AND FUTURE FORECASTS CAN REFINE THE TIMING AT THE TAF
SITES. MONDAY AFTERNOON AND EVENING TSRA COVERAGE IS NOT EXPECTED
TO BE AS WIDESPREAD OR AFFECT THE TAF SITES AS LONG AS THE
ACTIVITY SUNDAY NIGHT.
&&
.HYDROLOGY...
ISSUED AT 800 PM CDT SUN MAY 19 2013
CONSIDERED AN EXPANSION TO THE FLASH FLOOD WATCH BUT BELIEVE THE
AREA IS WELL PLACED. WITH THE THUNDERSTORMS MOVING IN FROM
IOWA...THERE SHOULD BE A SCOURING EASTWARD AND END TO THE RAIN IN
NERN IA.
EXPECTING THE CEDAR RIVER TO RISE DOWNSTREAM OF OSAGE...CHARLES
CITY WILL SEE A LARGE JUMP IN THE NEXT 12 HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MNZ079-086-087-094-
095.
IA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR IAZ008.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BAUMGARDT
HYDROLOGY....RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1126 PM CDT SUN MAY 19 2013
.UPDATE...
SEVERE SQUALL LINE AND TRAILING STRATIFORM REGION OVER ERN IA TO
MOVE ACROSS THE CWA BETWEEN 05Z-10Z. BOUNDARY LAYER WILL ONLY
STABILIZE IN THE LOWEST 1 KFT WITH ELEVATED CAPES OF 1000-2000
J/KG AVAILABLE FOR THE SQUALL LINE. THUS SVR WIND GUSTS WILL BE
CAPABLE AT GROUND LEVEL. AFTER CONVECTION ENDS AROUND
SUNRISE...THERE IS NO OBVIOUS TRIGGER FOR MON AND MON NT AS THE
LOW PRESSURE AREA WILL REMAIN OVER MN. THE WARM FRONT WILL LIFT
INTO CENTRAL WI WITH GOOD AMOUNTS OF CAPE AND VERY STRONG DEEP
LAYER SHEAR IN PLACE. 500 MB HEIGHTS WILL SLOWLY FALL THROUGH THIS
PERIOD WITH ONLY WEAK CAPPING. THUS EXPECT MORE STRONG TO SEVERE
THUNDERSTORMS BUT TIMING IS DIFFICULT...LATE MON AFTERNOON AND
NIGHT ARE BEST ESTIMATES. ALL MODES OF SEVERE WX ARE POSSIBLE.
&&
.AVIATION/06Z TAFS/...A STRONG TO SEVERE SQUALL LINE WILL AFFECT
SRN WI DURING THE OVERNIGHT. A BREAK IN CONVECTION WILL THEN LIKELY
OCCUR WITH MORE POSSIBLE LATE MON AFTERNOON AND NIGHT. CIGS AND
VSBYS WILL BE GREATLY REDUCED IN THE TSTORMS WITH SOME MVFR CIGS
AND VSBYS POSSIBLE IN THE STRATIFORM REGION OF THE SQUALL LINE
DURING THE OVERNIGHT. OTHERWISE...SCT-BKN040 CUMULUS TO CUMULUS
CONGESTUS WILL PREVAIL MON AND MON NT.
&&
.PREV DISCUSSION... /ISSUED 348 PM CDT SUN MAY 19 2013/
VERY SHORT TERM...TONIGHT AND MONDAY...FORECAST CONFIDENCE MEDIUM.
WATER VAPOR IMAGERY IS SHOWING A SERIES OF SHORT WAVES/VORT
MAXES/PERTURBATIONS LINING UP FROM THE PACIFIC NW TO NORTHERN NEW
MEXICO/PANHANDLE REGION OF TX/OK THAT WILL BE DIVING INTO AND AROUND
THE BASE OF A DEEPENING TROUGH OVER THE DAKOTAS. THESE WILL PROVIDE
THE TRIGGERING MECHANISM FOR SUCCESSIVE ROUNDS OF SHOWERS AND STORMS
OVER THE NEXT 24 TO 36 HOURS.
A CLUSTER OF THUNDERSTORMS OVER SOUTH CENTRAL WI PRODUCING WINDS OF
50 TO 60 MPH IS WEAKENING AS IT MOVES FURTHER EAST INTO THE MORE
CAPPED ENVIRONMENT. A COUPLE OF SITES HAVE REPORTED GUSTS OF 35 TO
45 MPH IN THE WAKE OF THIS SMALL TSTORM COMPLEX.
NOW KEEPING AN EYE ON CONVECTION IN CENTRAL IOWA THAT IS ASSOCIATED
WITH ANOTHER SHORTWAVE TROUGH EXTENDING SE FROM THE MCV NOW OVER SW
MN. HRRR AND WRF-ARW MODELS BRING THIS AREA OF CONVECTION INTO SOUTH
CENTRAL WI AROUND 23Z. SLIGHT STRENGTHENING OF THE LLJ OVER IL
DURING THIS TIME ALONG WITH 850MB WARM AIR ADVECTION AND THIS
SHORTWAVE TROUGH...ALONG WITH MIXED LAYER CAPE 1000-1300 J/KG AND
SHEAR PARAMETERS /0-3KM SHEAR AROUND 20 KNOTS WILL BE FAVORABLE TO
SUPPORT ONGOING SURFACE-BASED CONVECTION LATE THIS AFTERNOON...AND
MORE ELEVATED CONVECTION AS IT MOVES TOWARD SOUTHEAST WI. THE SEVERE
POTENTIAL IS THERE FOR HAIL AND STRONG WINDS.
THERE IS ANOTHER SHORTWAVE ON THE HEELS OF THIS ONE...CURRENTLY OVER
SOUTHWEST IOWA. MESOSCALE MODELS SHOW THIS ONE TO BE THE SOURCE OF
AN OVERNIGHT CONVECTIVE COMPLEX...LIKELY HITTING SOUTHERN WI BETWEEN
06Z TO 12Z MONDAY...BUT EXACT TIMING IS DEBATABLE. CORFIDI VECTORS
WEAKEN OVER SOUTHERN WI DURING THIS TIME...SUGGESTING SLOW-MOVING
THUNDERSTORMS AND THE HEAVY RAIN/LOCALIZED FLOODING POTENTIAL.
SEVERE HAIL AND WINDS WILL ALSO BE POSSIBLE WITH THIS ROUND.
THEN IT WILL BE A MATTER OF HOW QUICKLY THE CONVECTIVE DEBRIS CAN
CLEAR IN ORDER FOR THE ATMOSPHERE TO RE-DESTABILIZE IN SOUTHERN WI.
IT WILL ALSO DEPEND ON WHERE THE EFFECTIVE WARM FRONT SETS
UP...WHICH WILL BE BASED ON OVERNIGHT CONVECTION. MODELS ARE
SUGGESTING THE WARM FRONT WILL BE UP IN NORTHERN WI BY MONDAY
AFTERNOON...BUT SOMETIMES MODELS TEND TO MOVE IT TOO FAR TO THE
NORTH. WILL NEED TO MONITOR THIS TREND.
THE CRAVEN-WIEDENFELD AGGREGATE SEVERE PARAMETER /CWASP/ IS
BASICALLY A SCORING/RATING SYSTEM FOR SEVERE WEATHER PARAMETERS. A
VALUE OVER 80 CORRESPONDS WITH A GOOD CHANCE FOR SEVERE WEATHER IN
THAT AREA. WE CONTINUE TO SEE VALUES IN THE 80S OVER SOUTHERN WI 18Z
MONDAY TO 06Z TUESDAY. IF THE ATMOSPHERE CAN RECOVER FROM ANY
OVERNIGHT CONVECTION IN TIME...THEN SURFACE-BASED SEVERE STORMS WILL
BE LIKELY. LARGE HAIL...STRONG WINDS AND TORNADOES WOULD ALL BE
POSSIBLE. STAY TUNED TO THE FORECAST.
SHORT TERM...MONDAY NIGHT THROUGH WEDNESDAY.
MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE MEDIUM.
TIMING CONTINUES TO BE EVERYTHING WITH THE SERIES OF SHORT
WAVES/VORT MAXES/PERTURBATIONS...ROUNDING THE BASE OF THE CLOSED LOW
CENTERED NEAR THE DAKOTAS/MINNESOTA BORDER AND LIFTING NORTH
THROUGH THE REGION...THAT WILL BE THE TRIGGERING MECHANISMS FOR
SHOWERS AND THUNDERSTORMS.
ONGOING CONVECTION WILL BE TAPERING OFF...WITH INCREASING
CONVERGENCE AHEAD OF NEXT 850 MB SPEED MAX ASSOCIATED WITH ANOTHER
SHORT WAVE APPROACHING BETWEEN 06Z AND 12Z TUESDAY. WHILE BETTER
POTENTIAL FOR SEVERE APPEARS TIED TO STRONGER FORCING FOCUSING TO
THE SOUTHWEST...STILL LIKELY TO SEE THUNDER...WITH ELEVATED CAPE
BETWEEN 600 AND 1000 J/KG.
CWASP FOR ALL MODELS SHIFTS HIGHER PERCENTAGES TO THE SOUTH FOR
TUESDAY...BUT GFS/GEM AND TO SOME EXTENT THE ECMWF STILL HAVE HIGH
ENOUGH VALUES TO CONTINUE PROBABILITY OF SEVERE INTO TUESDAY.
TUESDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
THREAT FOR WIDESPREAD THUNDERSTORMS TAPERS OFF OVERNIGHT INTO
WEDNESDAY AS FOCUS OF LOW-LEVEL JET SHIFTS SOUTHEAST AS CLOSED
SYSTEM SHIFTS TO THE EAST TOWARD WISCONSIN...AND CONVECTIVE
PARAMETERS DIMINISH. A BLENDED SOLUTION TO BALANCE TIMING
DIFFERENCES KEEPS LIKELY THUNDER IN THE EASTERN CWA...MAINLY IN THE
MORNING...WITH CHANCES FOR SHOWERS IN THE WEST.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY. FORECAST CONFIDENCE
ALL THE MODELS SHIFT THE SURFACE LOW FAR ENOUGH EAST BY WEDNESDAY
NIGHT FOR COOL NORTHERLY WINDS TO PUSH IN. WILL HAVE TO KEEP CHANCES
OF SHOWERS IN THE FORECAST UNTIL 500 MB TROUGH CLEARS SOUTHERN
WISCONSIN THURSDAY EVENING. RIDGING BUILDS IN WITH OMEGA BLOCK
SETTING UP BRINGING DRY WEATHER AND BELOW NORMAL TEMPERATURES INTO
SATURDAY. THE CHANCE FOR SHOWERS AND THUNDERSTORMS RETURNS FOR
SATURDAY NIGHT AND SUNDAY WITH WARM AIR TRYING TO PUSH INTO THE
WESTERN GREAT LAKES AS EASTERN LOW SHIFTS AWAY AND SHORT WAVE
ENERGY EJECTING FROM WESTERN TROUGH BREAKS DOWN RIDGE.
AVIATION/00Z TAFS/...
THUNDERSTORMS IN SOUTH CENTRAL WI WILL DRIFT NORTHEAST AND
DISSIPATE LATE THIS AFTERNOON. ANOTHER BROKEN LINE OF
THUNDERSTORMS OVER NORTHEAST IOWA ARE EXPECTED TO TRACK INTO SOUTH
CENTRAL WI AROUND 23Z PER MESOSCALE MODELS. THEN ANOTHER ROUND OF
CONVECTION IS LOOKING MORE LIKELY FOR AFTER MIDNIGHT
TONIGHT...WHICH WOULD PROBABLY CLEAR SOUTHEAST WI EARLY MONDAY
MORNING. THUNDERSTORMS WILL HAVE THE POTENTIAL FOR STRONG WINDS
AND HAIL TONIGHT.
BEST CHANCE FOR SEVERE THUNDERSTORMS WITH A WIND/HAIL/TORNADO THREAT
IS LOOKING LIKE MONDAY AFTERNOON. SEE THE DISCUSSION ABOVE FOR
DETAILS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...GEHRING
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...REM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
548 PM MDT TUE MAY 21 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM MDT TUE MAY 21 2013
EXTENDED THE WIND ADVISORY UNTIL 6 PM MDT FOR MOST OF THE NEBRASKA
PANHANDLE. AT 2 PM MDT WINDS WERE GUSTING TO 51 MPH AT SCOTTSBLUFF
AND 44 MPH AT ALLIANCE. WINDS SHOULD BEGIN A SLOW DECREASE THE
REST OF THIS AFTERNOON AND THEN DROP OFF MORE QUICKLY THIS
EVENING.
WINDS WILL SHIFT TO THE NORTHEAST OVER EASTERN AREAS TONIGHT AND
THEN TURN TO THE SOUTHEAST WEDNESDAY. THIS WILL BEGIN TO ALLOW LOW
LEVEL MOISTURE TO ADVECT WESTWARD WHICH MAY ALLOW FOR INCREASING
CHANCES OF THUNDERSTORMS THROUGH THE WEEK. KEPT A SLIGHT CHANCE
FOR SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND ADJACENT
PLAINS FOR WEDNESDAY AFTERNOON. MODEL SOUNDINGS SHOWING STEEP
LAPSE RATES WITH LITTLE TO NO CONVECTIVE INHIBITION. INSTABILITY
IS NOT ALL THAT GREAT SO MAINLY LOOKING AT SHOWERS WITH A FEW WEAK
THUNDERSTORMS. MODELS DO SHOW AN ELEVATED WARM FRONT MOVE EAST
ACROSS THE FORECAST AREA WEDNESDAY NIGHT. THERE MAY BE ENOUGH
INSTABILITY AND LIFT TO KEEP ISOLATED SHOWERS AND WEAK
THUNDERSTORMS PECULATING INTO THE NIGH-TIME WHILE SHIFTING EAST
INTO WESTERN NEBRASKA.
SOUTH TO SOUTHEAST WINDS SHOULD BEGIN TO RAMP UP WEDNESDAY NIGHT
AND THURSDAY. MODELS HAVE BEEN TRENDING STRONGER WITH LOW LEVEL
FLOW THURSDAY. NAM AND GFS BUFKIT SOUNDING AT LUSK SHOWING 50 KT
WINDS A FEW THOUSAND FEET ABOVE GROUND LEVEL THURSDAY AFTERNOON.
SOUNDINGS ALSO SHOWING A VERY STRONG LOW LEVEL INVERSION DUE IN
PART TO THE MOIST LOW LEVEL FLOW. KEPT A CHANCE FOR THUNDERSTORMS
MAINLY OVER THE MOUNTAINS THURSDAY. MOST LIKELY A FEW STORMS WILL
DEVELOP OVER THE LARAMIE RANGE...BUT WITH SUCH A STRONG CAP IN
PLACE...STORMS MAY HAVE A TOUGH TIME MOVING INTO LOWER ELEVATIONS.
ALONG WITH THE INVERSION EXPECTING A LOT OF STRATUS THURSDAY.
STRATUS SHOULD PUT A LID ON TEMPERATURES. FOLLOWED THE PREVIOUS
FORECAST SHIFT IN LOWERING DAYTIME HIGHS FOR THURSDAY. ALSO WARMED
THE LOW A BIT WEDNESDAY NIGHT AND THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 325 PM MDT TUE MAY 21 2013
FIRST UPPER SHORTWAVE EJECTING FROM PAC NW UPPER LOW WILL MOVE
ACROSS THE AREA FRIDAY MORNING. TIMING SUCH THAT THERE MAY BE A BIT
OF CONVECTION OVER MAINLY THE PANHANDLE BUT IF SFC BOUNDARY MOVES
FAR ENOUGH EAST THE ACTIVITY WOULD BE EAST OF THE CWA. WILL KEEP
SOME LOW POPS IN PLACE UNTIL BETTER CERTAINTY. SW FLOW ALOFT
REMAIN IN PLACE OVER THE CWA OVER THE WEEKEND INTO EARLY NEXT WEEK
SO SOME AFTERNOON AND EVENING CONVECTION WILL CONTINUE TO BE A
POSSIBILITY...THOUGH TIMING WILL BE DIFFICULT. ECMWF DEPICTING IT
PRETTY MUCH DAILY WHILE GFS DRIER. WILL KEEP POPS WHERE IT LOOKS
MORE FAVORABLE SUCH AS SUNDAY AND MONDAY. TEMPERATURES WILL BE
ON THE WARM SIDE FOR MUCH OF THE PERIOD...GENERALLY A LITTLE ABOVE
SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 545 PM MDT TUE MAY 21 2013
LATEST SREF AND HRRR GUIDANCE SHOWING SOME WRAP AROUND LOW CLOUDS
MAKING IT INTO KCDR AND KAIA TONIGHT. UPSTREAM OBSERVATIONS IN
SOUTH DAKOTA REPORTING CEILINGS DOWN AROUND 1500 FEET...SO THEIR
FORECAST SEEMS REASONABLE. WENT AHEAD AND LOWERED CEILINGS AT KCDR
AND KAIA TONIGHT. VFR ELSEWHERE.
&&
.FIRE WEATHER...
ISSUED AT 325 PM MDT TUE MAY 21 2013
WINDS WILL DROP OFF QUICKLY THIS EVENING AND BECOME LIGHT. WINDS
WILL REMAIN ON THE LIGHT SIDE MAINLY IN THE 10 TO 15 MPH RANGE
WEDNESDAY BUT WILL BEGIN TO INCREASE WEDNESDAY NIGHT...WITH STRONG
SOUTHEAST WINDS ALONG AND EAST OF THE LARAMIE RANGE FOR THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MAINLY BE CONFINED TO
THE MOUNTAINS WEDNESDAY AND THURSDAY AFTERNOON.
WEATHER CONDITIONS WILL VARY GREATLY FROM WEST TO EAST OVER THE
FORECAST AREA LATE THIS WEEK AND WEEKEND. RELATIVELY MOIST
CONDITIONS WILL BE FOUND EAST OF THE LARAMIE RANGE UNDER SOUTH TO
SOUTHEAST LOW LEVEL FLOW...WHILE WEST OF THE LARAMIE RANGE DRY
SOUTHWEST FLOW WILL DOMINATE PRODUCING LOW HUMIDITY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR NEZ003-019>021-054-
055-095-096.
&&
$$
SHORT TERM...LIEBL
LONG TERM...RE
AVIATION...CLAYCOMB
FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS ALBANY NY
550 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE
SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST
INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG
COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW
PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH
COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE
OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR
THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH
UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TSTMS HAVE ENDED AND ONLY SCT -SHRA REMAIN MAINLY OVER S VT AND
BERKSHIRE COUNTY. SOME ISOLD -SHRA ARE ALONG THE S TIER. FOR THE
NEXT SVRL HOURS MOST OF THIS ACTIVITY WILL DIMINISH AND END.
CLOUDS OVER MUCH OF FCA WILL THIN WITH INCRG SUNSHINE FOR A FEW
HRS.
THE HOOSIC RIVER AND SOME SMALL STREAMS IN SOUTHERN VERMONT HAVE
REACHED BANKFUL AND MAY BRIEFLY EXCEED FLOOD THIS MORNING BEFORE
RECEDING. WARNINGS AND ADVISORIES HAVE BEEN ISSUED TO COVER THESE
SITUATIONS.
AT SFC WMFNT IS N OF FCA. IT WILL MOVE TO ST LAWRENCE VLY TO
MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP
IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL
LLVL MOISTURE/CLOUDS FM TUES CONVECTION
WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT
OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED
TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE
TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF
1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE
FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY.
NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN.
GOING TO HRRR FOR THE LATE AFTN:
POU/ALB/GFL
CAPE 2000/1812/1777
J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2
STORM SPEED 24/18/18
SRH 175/156/106
MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE
WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM
MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN
CAPE AROUND 1000-1200 J/KG.
PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL
WITH VALUES OF 1.50-1.8 INCHES.
SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND
BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER
FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL
NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF
THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED
TIME OF LATER IN THE AFTN AND EVENING.
CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS
FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE
60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC
LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST
LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO
BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN
PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG
DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS
WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS
ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY.
REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING
TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT.
BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC
COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS
DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS
WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW
MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS.
HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT.
BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME
PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF
LINGERING SKIES MAY ONLY BE PS SAT IN GFS.
TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS
A FEW DEG...OR HOLDING STEADY.
THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI
NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT
NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT.
THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A
COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND
WITH PERIODS OF RAW CHILLY RAIN.
THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO
MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN
ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO
THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL
REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME
TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC
LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A
FALL LIKE MEMORIAL DAY WEEKEND.
WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW
ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON
MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER.
GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20
MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD.
ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS
FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS
SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM
GRT PLAINS TO GRTLKS.
PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE
CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE
HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY
AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND
ABV BY TUESDAY AND WED.
WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE
MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON
AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL
START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM
COUNTY.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD
CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT
07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR
CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED
THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN
KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF
THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN.
ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF
MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW
1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD
SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000
FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES
THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND
TRENDS CHANGE.
VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z
UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING.
MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE
LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE
THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE
TOMORROW AFTERNOON AND EVENING.
WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE
AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO
SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD
BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING.
OUTLOOK...
WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN.
WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF
AND KPOU CHC -SHRA/-TSRA.
THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL
CONTINUE INTO FRIDAY.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON.
WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING
SOUTHWEST AROUND 10MPH THURSDAY.
&&
.HYDROLOGY...
PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE
WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN
THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN
FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN
BANK RISES ARE LIKELY IN LARGER RIVERS.
3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT
THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY.
DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS...
BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST
THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS
WILL THIS AFTERNOON INTO THURSDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...SNYDER
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...NAS
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
411 AM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. WARM
AND HUMID CONDITIONS CONTINUE INTO THURSDAY AND FRIDAY WITH
SHOWERS AND SCATTERED STRONG THUNDERSTORMS POSSIBLE. COOLER AND
LESS HUMID CONDITIONS ARE EXPECTED FOR THIS HOLIDAY WEEKEND AS
HIGH PRESSURE BUILDS ACROSS THE NORTHEAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
4 AM UPDATE...
CONTINUING TO MONITOR WAVES OF CONVECTION THIS MORNING. LATEST
RUNS OF THE HRRR APPEAR TO HAVE THE BEST HANDLE ON THESE BANDS OF
CONVECTION...ALTHOUGH ITS TIMING WAS SLOW BY A FEW HOURS. LEANED
HEAVILY ON THE 05Z HRRR WITH THE APPROPRIATE TIMING ADJUSTMENT
FOR THE EARLY MORNING FORECAST. SHOWERS AND THUNDERSTORMS ARE
REASONABLY HOLDING TOGETHER IN A HIGH SHEAR/LOW CAPE ENVIRONMENT.
LATER TODAY...EXPECTING THE STALLED BACK-DOOR COLD FRONT TO MOVE
BACK NORTH AS A WARM FRONT. THERE ARE STILL SOME QUESTIONS AS TO
HOW FAST THIS WILL HAPPEN. CURRENTLY THINKING THERE IS NOT ENOUGH
PUSH TO DRIVE IT COMPLETELY THROUGH SOUTHERN NEW ENGLAND. AS
SUCH...MAINTAINED COASTAL SEABREEZE FRONTS ALONG BOTH COASTS.
THIS HAS BIG RAMIFICATIONS FOR TEMPERATURES ALONG THE EAST COAST.
SHOULD THIS FRONT GET ENOUGH PUSH...CURRENT FORECAST TEMPERATURES
ARE LIKELY 5-10 DEGREES TOO LOW ALONG THE IMMEDIATE COASTLINE. AM
MORE CONFIDENT WITH TEMPERATURES FARTHER INLAND. SHOULD THERE BE
MORE SUNSHINE THAT CURRENTLY THINKING...LIKELY TOO LOW FARTHER
INLAND AS WELL.
THINKING THERE WILL BE MORE CLOUDS THAN SUNSHINE TODAY OWING TO
LOTS OF CONVECTIVE DEBRIS FROM THE OVERNIGHT SHOWERS...AS WELL AS
NEW CONVECTIVE CLOUDS AS WE HEAD INTO THIS AFTERNOON.
MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED LATER TODAY. THERE IS
THE POSSIBILITY FOR MORE ISOLATED SEVERE WEATHER. THE GREATEST
RISK SHOULD BE FARTHER WEST OF OUR REGION WHERE THE MORE FAVORABLE
COMBINATION OF INSTABILITY AND SHEAR SHOULD BE. THE BEST ADVICE IS
TO KEEP AN EYE ON THE SKY AND LATER FORECASTS IF YOU WILL BE
OUTDOORS THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...MORE OF THE SAME TONIGHT. WARM FRONT CONTINUES TO PUSH
NORTH AS STRONGER SOUTH TO SOUTHWEST SYNOPTIC FLOW DEVELOPS.
DECENT INSTABILITY PERSISTS THROUGH THE NIGHT. SO THINKING WE WILL
BE SEEING ANOTHER NIGHT OF ISOLATED TO SCATTERED THUNDERSTORMS.
THE GREATEST RISK OF THESE WILL BE ACROSS THE INTERIOR...AWAY FROM
THE STABILIZING INFLUENCE OF THE OCEAN.
THURSDAY...SOUTHERN NEW ENGLAND REMAINS IN THE WARM SECTOR OF A
LOW PRESSURE MOVING FROM THE GREAT LAKES INTO THE SAINT LAWRENCE
RIVER VALLEY. THIS LOW HAS A RATHER AMPLIFIED UPPER SYSTEM...SO
ITS COLD FRONT WILL BE SLOW TO MOVE ACROSS OUR REGION.
EXPECTING MORE ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS.
VERY HUMID AIRMASS IN PLACE AS WELL...WITH PRECIPITABLE WATER
VALUES AROUND 1.7 INCHES. WILL LIKELY SEE SOME HEAVY DOWNPOURS
WITH SOME SHOWERS...ALONG WITH SOME HAIL AND GUSTY WINDS. MAY NOT
QUITE REACH SEVERE THRESHOLDS AS CLOUDS WILL BE MORE PREVALENT...
THUS TEMPERATURES SHOULD BE LOWER THAN WEDNESDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY
* COOLER AND LESS HUMID FOR THE WEEKEND
CONFIDENCE LEVEL/MODEL GUIDANCE...MODERATE CONFIDENCE IN OVERALL
FORECAST. 00Z MODELS CONTINUE TO SLOW DOWN THE ELONGATED TROUGH
MOVING ACROSS THE EASTERN HALF OF THE CONUS. THERE IS STILL SOME
TIMING DIFFERENCES ON WHEN THE SYSTEM WILL PUSH THROUGH THE
NORTHEAST. REGARDLESS APPEARS THAT ELONGATED TROUGH WILL MOVE INTO
NEW ENGLAND EVENTUALLY BECOMING A CUTOFF LOW BY THE WEEKEND. THIS
LOW WILL EVENTUALLY MOVE INTO THE MARITIMES BY THE BEGINNING OF
THE WORK WEEK AS HIGH PRESSURE MOVES IN. HAVE HIGH CONFIDENCE THAT
PRECIP WILL OCCUR ON FRIDAY AND COOLER TEMPS WILL DOMINATE THE
REGION FOR THE WEEKEND. LOW CONFIDENCE IN FORECAST AFTER TUES.
DETAILS...
THURSDAY NIGHT INTO FRIDAY...
UPPER LEVEL TROUGH WILL PUSH THROUGH THE EASTERN GREAT LAKES
REGION EVENTUALLY PUSHING A COLD FRONT THROUGH SOUTHERN NEW
ENGLAND. MODELS CONTINUE TO SLOW THE TIMING OF THE FRONT DOWN...SO
BELIEVE THAT IT MOVE THROUGH SOMETIME ON FRIDAY. BECAUSE OF THE
MODEL DIFFERENCE HAVE LOW CONFIDENCE IN TIMING.
REGARDLESS...BELIEVE THAT SHOWERS AND THUNDERSTORMS WILL MOVE
THROUGH WITH TEMPS NEAR AVG. CANNOT RULE OUT A FEW STRONG
THUNDERSTORMS ESPECIALLY ACROSS REGIONS SOUTH OF THE I-84
CORRIDOR. MODELS INDICATE SOME INSTABILITY WITH ABOUT 25KTS OF
SHEAR. PWAT VALUES OF OVER 1.5 INCHES LEADS FORECASTER TO BELIEVE
THAT HEAVY DOWNPOURS IS THE MAIN THREAT...BUT WITH FALLING HEIGHTS
AS COLD FRONT APPROACHES...SMALL HAIL AND GUSTY WINDS IS NOT OUT
OF THE QUESTION. ANY CHANCE FOR STRONG STORMS TO DEVELOP WILL
DIMINISH AFTER SUNSET AS DIURNAL HEATING IS LOST.
WEEKEND...TRICKY FORECAST IS PLAYING OUT FOR THE WEEKEND. MODELS
HAVE INDICATED THAT THE ELONGATED TROUGH WILL CUT OFF OVER THE MID
ATLANTIC AND SLOWLY ROTATE OVER NEW ENGLAND FOR THE WEEKEND. THIS
WILL ALLOW FOR MUCH COOLER AIR...WELL BELOW AVG AND EVEN HAS
SLOWED DOWN THE TIMING OF PRECIP. BELIEVE THAT PRECIP MAY LINGER
INTO SAT...BUT HAVE LOW CONFIDENCE THAT PRECIP WILL OCCUR ON
SUNDAY. FOR NOW HAVE CONTINUED WITH THE SLOW DOWN TREND IN THE
FORECAST. EXPECT HIGHS REACHING INTO THE MID TO UPPER 60S WITH
LOWS DROPPING INTO THE MID TO UPPER 30S. IF SKIES CLEAR OUT AS
THIS COLD POOL SITS OVER US...THERE IS A POSSIBILITY THAT
FROST/FREEZE HEADLINES MAY BE NEEDED AS THE ENTIRE REGION IS
OFFICIALLY IN THE GROWING SEASON.
MONDAY AND BEYOND...SURFACE HIGH PRESSURE WILL BE IN CONTROL FOR
THE FIRST HALF OF NEXT WEEK. THIS WILL HELP TEMPS REACH SEASONAL
CONDITIONS. APPEARS THAT THERE IS LIMITED MOISTURE KEEPING THE
FORECAST DRY...HOWEVER CANNOT RULE OUT A SPOT SHOWER OR TWO...ESP
IF SEA BREEZES DEVELOPS.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE IN TIMING AND AREAL COVERAGE OF
STRATUS AND FOG THROUGH THIS MORNING.
THROUGH 12Z...EXPECTING BANDS OF STRONG ENOUGH CONVECTION TO
AVOID. THESE BANDS OF CONVECTION SHOULD CONTINUE TO WEAKEN AS IT
MOVES EAST. MIXED CONDITIONS THIS MORNING WITH WIDESPREAD IFR
ACROSS THE MA COASTAL PLAIN AND MUCH OF RI AND NORTHERN
CT...IMPROVING TO POCKETS OF MVFR ACROSS THE INTERIOR. EVEN SOME
LOCALIZED VFR POSSIBLE.
TODAY...EXPECT MVFR-LIFR CONDITIONS TO GRADUALLY IMPROVE TO VFR
14-16Z AS SW WINDS DEVELOP. IFR MAY PERSIST MOST OF THE DAY AT
KACK. ISOLATED TO SCATTERED CONVECTION BECOMING MORE WIDESPREAD
THIS AFTERNOON...ESPECIALLY WEST OF KMHT-KORH-KIJD.
TONIGHT...MODERATE CONFIDENCE IN TRENDS. EXPECT VARIABLE
CONDITIONS DEPENDING UPON SHOWER AND FOG DEVELOPMENT. BETTER SHOT
FOR IFR VSBYS IN FOG ALONG S COAST ON S-SW WINDS AND MILD TEMPS
MAINLY AFTER MIDNIGHT. SCT SHOWERS/TSTMS ACROSS MOST OF THE REGION
THOUGH BEST SHOT ACROSS CENTRAL AND WESTERN AREAS...WITH MVFR-IFR
CIGS/VSBYS. MAY SEE LOCAL HEAVY DOWNPOURS. LOW CONFIDENCE ON
TIMING AND PLACEMENT.
THURSDAY...MODERATE CONFIDENCE IN TRENDS. VERY UNSETTLED PATTERN
AHEAD OF APPROACHING COLD FRONT. VARIABLE CONDITIONS BETWEEN VFR
AND MVFR/IFR IN SHRA/TSRA/PATCHY FOG. COLD FRONT CROSSES THE
REGION THU NIGHT...SO WILL SEE IMPROVING CONDITIONS ACROSS WESTERN
AREAS AFTER MIDNIGHT THU NIGHT...THEN INTO CENTRAL SECTIONS AFTER
06Z-07Z. MAY SEE SW WIND GUSTING UP TO 20-25 KT DURING THE DAY AS
WELL. WINDS SHIFT TO W-NW ACROSS CENTRAL AND WESTERN AREAS AFTER
MIDNIGHT.
KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS...LOWER CONFIDENCE
IN TIMING OF LOWER CONDITIONS AND CONVECTION THIS AFTERNOON.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING
OF CONVECTION THIS AFTERNOON. COULD SEE BRIEF IFR IN A BAND OF
TSRA. APPEARS THIS BAND WILL PASS TO THE NORTH OF THE TERMINAL
THROUGH 0830Z. WILL CONTINUE TO MONITOR.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY...LOW CONFIDENCE. MODERATE CONFIDENCE
ON SEA BREEZE DEVELOPMENTS. VERY UNSETTLED PATTERN WITH
VARIABILITY BETWEEN VFR CONDITIONS AND MVFR/IFR CONDITIONS IN
SHRA/TSRA/FOG. IMPROVING CONDITIONS LATE FRIDAY NIGHT INTO
SATURDAY MORNING.
SATURDAY-SUNDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TONIGHT.
WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
THROUGH TODAY. INCREASING SW FLOW WILL RESULT IN SEAS BUILDING
OVER THE SOUTHERN COASTAL WATERS. SMALL CRAFT ADVISORY ISSUED FOR
LATER TODAY INTO THURSDAY FOR COASTAL WATERS WHERE CONFIDENCE IS
HIGHEST. WINDS SHOULD CONTINUE TO INCREASE TONIGHT INTO THURSDAY
AS A LOW PRESSURE MOVES INTO THE GREAT LAKES. AS SUCH COULD SEE
SMALL CRAFT ADVISORY EXPAND INTO MORE OF THE COASTAL WATERS AROUND
CAPE COD DUE TO 25 KT WIND GUSTS. CONFIDENCE IS NOT YET HIGH
ENOUGH TO ISSUE ADVISORIES FOR THOSE WATERS AT THIS TIME.
EXPECT LOW VSBYS IN HEAVY SHOWERS AND PATCHY FOG AT TIMES.
ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE AS WELL...ESPECIALLY
NEAR SHORE.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE TO HIGH CONFIDENCE. COLD FRONT WILL BE SLOW TO
CLEAR THE WATERS...SO EXPECT SW WINDS IN PLACE FOR A PORTION OF
THE DAY BEFORE SHIFTING TO W-NW ACROSS THE EASTERN WATERS.
THE WEEKEND...MODERATE CONFIDENCE. SEAS WILL REMAIN ABOVE SCA FOR
MOST OF THE WEEKEND ESP FOR THE OUTER WATERS. GUSTY NW BEHIND THE
FRONT WILL BRING GUSTS CLOSE TO GALE FORCE SAT INTO SAT NIGHT.
EXPECT BOTH SEAS AND WIND TO SLOWLY SUBSIDE THROUGHOUT THE DAY
ON SUNDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THURSDAY FOR
ANZ255-256.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM EDT
THURSDAY FOR ANZ235-254.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT
THURSDAY FOR ANZ237.
&&
$$
SYNOPSIS...BELK/DUNTEN
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...DUNTEN
AVIATION...BELK/DUNTEN
MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
321 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE
SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST
INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG
COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW
PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH
COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE
OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR
THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH
UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
LINE OF THUNDERSTORMS EAST OF I-88 CORRIDOR MOVING THROUGH FCA
ATTM. MAINLY HEAVY RAIN AND FREQ LIGHTNING. AREAS OF MODERATE RAIN
EXTEND BEHIND IT.
MOST AREAS TO BE IMPACTED WILL SEE ANOTHER 0.5 TO 1.O INCH OF RAIN
BRINGING TOTALS FOR TODAY UP TO 2-3 INCHES IN MOST AREAS IMPACTED
WITH SOME ISOLD 4 INCH AMOUNTS. AREAL FLOOD ADVISORY HAS BEEN
ISSUED FROM MHWK VLY AND ADJACENT AREAS INTO S VT/BERKSHIRE COUNTY
FOR OVERNIGHT TO COVER ANY SMALL STREAM AND URBAN FLOODING.
THIS LINE SHOULD EXIT MOST OF UPSTATE NY/VT AND W MA NEXT 1.5 TO
2 HRS...EXCEPT CATSKILLS AND MID HUDSON VLY WHERE IT IS JUST
ARRIVING IN AREAS THAT HAVE NOT HAD MUCH PCPN AT ALL OR SINCE
SINCE LATE TUES AFTN. IT SHOULD THEN DIMINISH AND END OVERNIGHT
AT SFC WMFNT IS LIFTING NE THROUGH FCA OVERNIGHT AND WILL BE ALONG
N TIER OR N OF RGN WED MRNG. IT WILL MOVE TO ST LAWRENCE VLY TO
MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP
IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL
LLVL MOISTURE/CLOUDS FM TUES CONVECTION
WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT
OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED
TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE
TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF
1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE
FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY.
NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN.
GOING TO HRRR FOR THE LATE AFTN:
POU/ALB/GFL
CAPE 2000/1812/1777
J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2
STORM SPEED 24/18/18
SRH 175/156/106
MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE
WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM
MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN
CAPE AROUND 1000-1200 J/KG.
PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL
WITH VALUES OF 1.50-1.8 INCHES.
SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND
BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER
FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL
NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF
THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED
TIME OF LATER IN THE AFTN AND EVENING.
CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS
FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE
60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC
LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST
LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO
BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN
PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG
DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS
WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS
ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY.
REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING
TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT.
BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC
COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS
DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS
WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW
MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS.
HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT.
BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME
PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF
LINGERING SKIES MAY ONLY BE PS SAT IN GFS.
TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS
A FEW DEG...OR HOLDING STEADY.
THE WEEKEND FCST IS DETERIORATING...
THE GFS IS PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI
NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT
NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT.
THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A
COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND
WITH PERIODS OF RAW CHILLY RAIN.
THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO
MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN
ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO
THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL
REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME
TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC
LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A
FALL LIKE MEMORIAL DAY WEEKEND.
WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT. ATTM WILL MAKE NO
CHANGES BEYOND SAT NT TO MINIMIZE FLIP FLOPPING GIVEN THE SPREAD
IN MODELS SOLUTIONS ATTM.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION SUNDAY. THE HIGH
WILL SHIFT EASTWARD ACROSS THE REGION AND OFFSHORE EARLY NEXT
WEEK. TEMPERATURES WILL GRADUALLY MODERATE AS THE HIGH SHIFTS TO
THE EAST WITH NEAR SEASONABLE TEMPERATURES FOR MONDAY.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK
VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND
EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON
MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD
CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT
07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR
CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED
THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN
KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF
THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN.
ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF
MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW
1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD
SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000
FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES
THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND
TRENDS CHANGE.
VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z
UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING.
MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE
LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE
THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE
TOMORROW AFTERNOON AND EVENING.
WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE
AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO
SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD
BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING.
OUTLOOK...
WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN.
WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF
AND KPOU CHC -SHRA/-TSRA.
THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL
CONTINUE INTO FRIDAY.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON.
WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING
SOUTHWEST AROUND 10MPH THURSDAY.
&&
.HYDROLOGY...
PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE
WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN
THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN
FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN
BANK RISES ARE LIKELY IN LARGER RIVERS.
3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT
THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY.
DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS...
BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST
THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS
WILL THIS AFTERNOON INTO THURSDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...SNYDER
SHORT TERM...SNYDER
LONG TERM...IAA
AVIATION...NAS
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
241 AM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. WARM
AND HUMID CONDITIONS CONTINUE INTO THURSDAY AND FRIDAY WITH
SHOWERS AND SCATTERED STRONG THUNDERSTORMS POSSIBLE. COOLER AND
LESS HUMID CONDITIONS ARE EXPECTED FOR THIS HOLIDAY WEEKEND AS
HIGH PRESSURE BUILDS ACROSS THE NORTHEAST.
&&
.NEAR TERM /THROUGH TODAY/...
2 AM UPDATE...
CONTINUING TO MONITOR WAVES OF CONVECTION THIS MORNING. LATEST
RUNS OF THE HRRR APPEAR TO HAVE THE BEST HANDLE ON THESE BANDS OF
CONVECTION...ALTHOUGH ITS TIMING WAS SLOW BY A FEW HOURS. LEANED
HEAVILY ON THE HRRR WITH THE APPROPRIATE TIMING ADJUSTMENT FOR THE
EARLY MORNING FORECAST. SHOWERS AND THUNDERSTORMS ARE REASONABLY
HOLDING TOGETHER IN A HIGH SHEAR/LOW CAPE ENVIRONMENT.
LATER TODAY...EXPECTING THE STALLED BACK-DOOR COLD FRONT TO MOVE
BACK NORTH AS A WARM FRONT. THERE ARE STILL SOME QUESTIONS AS TO
HOW FAST THIS WILL HAPPEN. CURRENTLY THINKING THERE IS NOT ENOUGH
PUSH TO DRIVE IT COMPLETELY THROUGH SOUTHERN NEW ENGLAND. AS
SUCH...MAINTAINED COASTAL SEABREEZE FRONTS ALONG BOTH COASTS.
THIS HAS BIG RAMIFICATIONS FOR TEMPERATURES ALONG THE EAST COAST.
SHOULD THIS FRONT GET ENOUGH PUSH...CURRENT FORECAST TEMPERATURES
ARE LIKELY 5-10 DEGREES TOO LOW ALONG THE IMMEDIATE COASTLINE. AM
MORE CONFIDENT WITH TEMPERATURES FARTHER INLAND. SHOULD THERE BE
MORE SUNSHINE THAT CURRENTLY THINKING...LIKELY TOO LOW FARTHER
INLAND AS WELL.
THINKING THERE WILL BE MORE CLOUDS THAN SUNSHINE TODAY OWING TO
LOTS OF CONVECTIVE DEBRIS FROM THE OVERNIGHT SHOWERS...AS WELL AS
NEW CONVECTIVE CLOUDS AS WE HEAD INTO THIS AFTERNOON.
MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED LATER TODAY. THERE IS
THE POSSIBILITY FOR MORE ISOLATED SEVERE WEATHER. THE GREATEST
RISK SHOULD BE FARTHER WEST OF OUR REGION WHERE THE MORE FAVORABLE
COMBINATION OF INSTABILITY AND SHEAR SHOULD BE. THE BEST ADVICE IS
TO KEEP AN EYE ON THE SKY AND LATER FORECASTS IF YOU WILL BE
OUTDOORS THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
TONIGHT...MORE OF THE SAME TONIGHT. WARM FRONT CONTINUES TO PUSH
NORTH AS STRONGER SOUTH TO SOUTHWEST SYNOPTIC FLOW DEVELOPS.
DECENT INSTABILITY PERSISTS THROUGH THE NIGHT. SO THINKING WE WILL
BE SEEING ANOTHER NIGHT OF ISOLATED TO SCATTERED THUNDERSTORMS.
THE GREATEST RISK OF THESE WILL BE ACROSS THE INTERIOR...AWAY FROM
THE STABILIZING INFLUENCE OF THE OCEAN.
THURSDAY...SOUTHERN NEW ENGLAND REMAINS IN THE WARM SECTOR OF A
LOW PRESSURE MOVING FROM THE GREAT LAKES INTO THE SAINT LAWRENCE
RIVER VALLEY. THIS LOW HAS A RATHER AMPLIFIED UPPER SYSTEM...SO
ITS COLD FRONT WILL BE SLOW TO MOVE ACROSS OUR REGION.
EXPECTING MORE ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS.
VERY HUMID AIRMASS IN PLACE AS WELL...WITH PRECIPITABLE WATER
VALUES AROUND 1.7 INCHES. WILL LIKELY SEE SOME HEAVY DOWNPOURS
WITH SOME SHOWERS...ALONG WITH SOME HAIL AND GUSTY WINDS. MAY NOT
QUITE REACH SEVERE THRESHOLDS AS CLOUDS WILL BE MORE PREVALENT...
THUS TEMPERATURES SHOULD BE LOWER THAN WEDNESDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* SHOWERS AND SCATTERED THUNDERSTORMS THURSDAY INTO FRIDAY
* COOLER AND LESS HUMID FOR THE HOLIDAY WEEKEND INTO EARLY NEXT
WEEK
OVERVIEW AND MODEL PREFERENCES...
MEDIUM RANGE OPERATIONAL MODEL SUITE SIGNALING AN AMPLIFIED...
SLOWLY PROGRESSIVE PATTERN ACROSS THE LOWER 48. AT THE START...
NOTING LONG WAVE TROUGH ACROSS THE UPPER PLAINS INTO THE WESTERN
LAKES THOUGH SOME DIFFERENCES IN POSITIONING...ALONG WITH H5
CUTOFF LOW MOVING INTO THE WEST COAST. LOWER THAN AVERAGE
CONFIDENCE ON THE PROGRESSION OF THE UPPER LEVEL PATTERN
OPERATIONAL SUITE...THOUGH GENERAL SURFACE SYSTEM POSITIONS AND
TIMING SIGNALS THROUGH THE HOLIDAY WEEKEND SEEM FAIRLY GOOD.
BETTER CONTINUITY AMONGST THE MODEL ENSEMBLES...SO LEANED CLOSER
TO THOSE BUT DID INCORPORATE A LITTLE OF THE 12Z GFS/00Z ECMWF
INTO THE EARLY PORTION OF THE LONG TERM /WED NIGHT TO FRI/.
ANTICIPATE SLOW BUT STEADY CHANGE TO THE UPPER PATTERN LATE THIS
WEEK AS UPPER TROUGH MOVES ACROSS THE EASTERN U.S. FRI-SAT. THIS
WILL BRING AIRMASS CHANGE AS UPPER WINDS SHIFT TO NW...BRINGING
COOLER AND DRIER CONDITIONS FOR A GOOD CHUNK OF THE HOLIDAY
WEEKEND. MODERATE TO HIGH CONFIDENCE CONTINUES FOR THE THU-FRI
TIMEFRAME WITH PERIODIC PRECIP AND SCATTERED CONVECTION...THEN
COLD FRONT SHOULD SWEEP THROUGH FRI NIGHT INTO EARLY SAT. MODERATE
CONFIDENCE BEYOND FRIDAY AS MAY SEE SOME TIMING ISSUES WITH THE
PASSAGE OF THE UPPER TROUGH SOMETIME SAT. FEW SHOWERS ARE
POSSIBLE...BUT TIMING IS DIFFICULT. EXPECT HIGH TEMPS THIS WEEKEND
TO RUN UP TO 5 DEGREES BELOW SEASONAL NORMS. DOES LOOK TO BE DRY
INTO EARLY NEXT WEEK WITH CLOSE TO SEASONABLE TEMPS.
DETAILS...
THURSDAY NIGHT...TIMING OF A COLD FRONT IS STILL IN QUESTION.
THOUGH APPEARS IT SHOULD SLOWLY CROSS THE REGION THU NIGHT...MAY
REACH THE COAST BY 12Z FRI. HAVE CARRIED LIKELY TO CAT POPS AS
COLD FRONT PASSES. LOOKS LIKE BEST INSTABILITY MAY PASS E
OVERNIGHT...BUT COULD STILL SEE SOME ELEVATED CONVECTION SO KEPT
SCT THUNDER IN THE FORECAST. TEMPS DO START DROPPING BACK TO THE
LOWER-MID 50S LATE ACROSS FAR INTERIOR AREAS.
FRIDAY...COLD FRONT SHOULD CLEAR THE E COAST DURING THE MORNING
BUT SOME SHOWERS MAY LINGER INTO MID MORNING ACROSS E MA.
OTHERWISE...EXPECT CONDITIONS TO IMPROVE THOUGH IT WILL BE
NOTICEABLY COOLER AND LESS HUMID.
SATURDAY THROUGH TUESDAY...BLOCKING UPPER PATTERN CONTINUES
ACROSS LABRADOR INTO GREENLAND THROUGH THIS TIMEFRAME...WHICH WILL
KEEP HIGH PRES BUILDING OUT OF CENTRAL CANADA DOWN THE EASTERN
SEABOARD. LONG RANGE MODELS AND ENSEMBLES ARE IN PRETTY GOOD
AGREEMENT WITH THIS PORTION OF THE FORECAST. EXPECT DRY AND COOL
CONDITIONS THROUGH THE HOLIDAY WEEKEND INTO EARLY NEXT WEEK. ON
SATURDAY...EXPECT DAYTIME HIGHS ONLY IN THE 60S...RUNNING 4 TO 8
DEGREES BELOW SEASONAL NORMS...THOUGH WILL MODIFY A BIT THROUGH
THE REMAINDER OF THIS TIMEFRAME.
DUE TO SEVERE WEATHER WATCH THIS AFTERNOON...KEPT PREVIOUS FORECAST
GOING FROM SUNDAY ONWARD...BUT LOOKS IN GOOD SHAPE WITH LATEST MODEL
GUIDANCE.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE IN TIMING AND AREAL COVERAGE OF
STRATUS AND FOG THROUGH THIS MORNING.
THROUGH 12Z...EXPECTING BANDS OF STRONG ENOUGH CONVECTION TO
AVOID. THESE BANDS OF CONVECTION SHOULD CONTINUE TO WEAKEN AS IT
MOVES EAST. MIXED CONDITIONS THIS MORNING WITH WIDESPREAD IFR
ACROSS THE MA COASTAL PLAIN AND MUCH OF RI AND NORTHERN
CT...IMPROVING TO POCKETS OF MVFR ACROSS THE INTERIOR. EVEN SOME
LOCALIZED VFR POSSIBLE.
TODAY...EXPECT MVFR-LIFR CONDITIONS TO GRADUALLY IMPROVE TO VFR
14-16Z AS SW WINDS DEVELOP. IFR MAY PERSIST MOST OF THE DAY AT
KACK. ISOLATED TO SCATTERED CONVECTION BECOMING MORE WIDESPREAD
THIS AFTERNOON...ESPECIALLY WEST OF KMHT-KORH-KIJD.
TONIGHT...MODERATE CONFIDENCE IN TRENDS. EXPECT VARIABLE
CONDITIONS DEPENDING UPON SHOWER AND FOG DEVELOPMENT. BETTER SHOT
FOR IFR VSBYS IN FOG ALONG S COAST ON S-SW WINDS AND MILD TEMPS
MAINLY AFTER MIDNIGHT. SCT SHOWERS/TSTMS ACROSS MOST OF THE REGION
THOUGH BEST SHOT ACROSS CENTRAL AND WESTERN AREAS...WITH MVFR-IFR
CIGS/VSBYS. MAY SEE LOCAL HEAVY DOWNPOURS. LOW CONFIDENCE ON
TIMING AND PLACEMENT.
THURSDAY...MODERATE CONFIDENCE IN TRENDS. VERY UNSETTLED PATTERN
AHEAD OF APPROACHING COLD FRONT. VARIABLE CONDITIONS BETWEEN VFR
AND MVFR/IFR IN SHRA/TSRA/PATCHY FOG. COLD FRONT CROSSES THE
REGION THU NIGHT...SO WILL SEE IMPROVING CONDITIONS ACROSS WESTERN
AREAS AFTER MIDNIGHT THU NIGHT...THEN INTO CENTRAL SECTIONS AFTER
06Z-07Z. MAY SEE SW WIND GUSTING UP TO 20-25 KT DURING THE DAY AS
WELL. WINDS SHIFT TO W-NW ACROSS CENTRAL AND WESTERN AREAS AFTER
MIDNIGHT.
KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS...LOWER CONFIDENCE
IN TIMING OF LOWER CONDITIONS AND CONVECTION THIS AFTERNOON.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING
OF CONVECTION THIS AFTERNOON. COULD SEE BRIEF IFR IN A BAND OF
TSRA. APPEARS THIS BAND WILL PASS TO THE NORTH OF THE TERMINAL
THROUGH 0830Z. WILL CONTINUE TO MONITOR.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE TO HIGH CONFIDENCE. MAY SEE LEFTOVER POCKETS OF
MVFR CIGS/VSBYS POSSIBLE ACROSS E MA THROUGH 14Z-15Z FRI.
OTHERWISE...VFR.
SATURDAY-SUNDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TONIGHT.
WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
THROUGH TODAY. INCREASING SW FLOW WILL RESULT IN SEAS BUILDING
OVER THE SOUTHERN COASTAL WATERS. WILL ISSUE A SMALL CRAFT
ADVISORY FOR ROUGH SEAS LATER TODAY INTO THURSDAY. WINDS SHOULD
CONTINUE TO INCREASE TONIGHT INTO THURSDAY AS A LOW PRESSURE MOVES
INTO THE GREAT LAKES.
EXPECT LOW VSBYS IN HEAVY SHOWERS AND PATCHY FOG AT TIMES.
ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE AS WELL...ESPECIALLY
NEAR SHORE.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE TO HIGH CONFIDENCE. COLD FRONT WILL BE SLOW TO
CLEAR THE WATERS...SO EXPECT SW WINDS IN PLACE FOR A PORTION OF
THE DAY BEFORE SHIFTING TO W-NW ACROSS THE EASTERN WATERS.
SATURDAY-SUNDAY...MODERATE CONFIDENCE. SEAS WILL REMAIN ABOVE
SMALL CRAFT FOR MOST OF THE WEEKEND ESPECIALLY ON THE OUTER
WATERS. NW GUSTS MAY APPROACH 25 KT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT
MARINE...BELK/EVT
AREA FORECAST DISCUSSION
NWS ALBANY NY
156 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE
SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST
INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG
COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW
PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH
COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE
OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR
THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH
UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
LINE OF THUNDERSTORMS EAST OF I-88 CORRIDOR MOVING THROUGH FCA
ATTM. MAINLY HEAVY RAIN AND FREQ LIGHTNING. AREAS OF MODERATE RAIN
EXTEND BEHIND IT.
MOST AREAS TO BE IMPACTED WILL SEE ANOTHER 0.5 TO 1.O INCH OF RAIN
BRINGING TOTALS FOR TODAY UP TO 2-3 INCHES IN MOST AREAS IMPACTED
WITH SOME ISOLD 4 INCH AMOUNTS. AREAL FLOOD ADVISORY HAS BEEN
ISSUED FROM MHWK VLY AND ADJACENT AREAS INTO S VT/BERKSHIRE COUNTY
FOR OVERNIGHT TO COVER ANY SMALL STREAM AND URBAN FLOODING.
THIS LINE SHOULD EXIT MOST OF UPSTATE NY/VT AND W MA NEXT 1.5 TO
2 HRS...EXCEPT CATSKILLS AND MID HUDSON VLY WHERE IT IS JUST
ARRIVING IN AREAS THAT HAVE NOT HAD MUCH PCPN AT ALL OR SINCE
SINCE LATE TUES AFTN. IT SHOULD THEN DIMINISH AND END OVERNIGHT
AT SFC WMFNT IS LIFTING NE THROUGH FCA OVERNIGHT AND WILL BE ALONG
N TIER OR N OF RGN WED MRNG. IT WILL MOVE TO ST LAWRENCE VLY TO
MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP
IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL
LLVL MOISTURE/CLOUDS FM TUES CONVECTION
WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT
OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED
TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE
TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF
1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE
FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY.
NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN.
GOING TO HRRR FOR THE LATE AFTN:
POU/ALB/GFL
CAPE 2000/1812/1777
J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2
STORM SPEED 24/18/18
SRH 175/156/106
MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE
WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM
MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN
CAPE AROUND 1000-1200 J/KG.
PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL
WITH VALUES OF 1.50-1.8 INCHES.
SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND
BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER
FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL
NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF
THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED
TIME OF LATER IN THE AFTN AND EVENING.
CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS
FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE
60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
THU-THU NIGHT...TRICKY FORECAST FOR STRONG TO SEVERE CONVECTION
ON THU WITH THE COLD FRONT STILL TO THE WEST. THE BETTER JET
DYNAMICS DURING THE AFTERNOON WITH APPRECIABLE MOISTURE AND
INSTABILITY IN PLACE. THE QUESTION WILL BE HOW MUCH HEATING OCCURS
WITH CLOUD COVER BEING AND ISSUE. LOCATIONS FROM THE CAPITAL
DISTRICT SOUTH AND EAST MAY HAVE THE BEST CHC FOR DESTABILIZATION
AND SEVERE WEATHER. NO SPC OUTLOOK YET...BUT DEFINITELY COULD SEE
ONE LATER FOR PARTS OF THE REGION. WILL MENTION SOME STRONG TO
SEVERE THUNDERSTORMS MAY BE POSSIBLE AGAIN ON THU. THE FRONT MOVES
THROUGH SLOWLY...WITH SHOWERS PERSISTING THROUGH THE OVERNIGHT. A
WEAK WAVE MOVE ALONG THE BOUNDARY TOO. THE COLD ADVECTION WILL
SLOWLY SEEP INTO THE REGION WITH LOWS IN THE 50S TO L60S BY
DAYBREAK FRI. HIGHS WILL GENERALLY BE IN THE 70S ON THU.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
COOLER AND DRY WEATHER EXPECTED FOR THE HOLIDAY WEEKEND. HAVE
FOLLOWED THE WEATHER PREDICTION CENTER`S GUIDANCE WHICH FAVORS THE
ECMWF ENSEMBLE MEAN WHICH HAS THE SUPPORT OF THE GEFS MEANS. WPC
INDICATES THE DETERMINISTIC/OPERATIONAL RUNS OF THE ECMWF AND GFS
DEVIATE SIGNIFICANTLY ENOUGH FROM THE STEADIER MEANS THAT THEY WERE
NOT INCORPORATION INTO THEIR FORECAST.
CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION AS WE HEAD INTO
THE WEEKEND BEHIND THE DEPARTING LOW PRESSURE SYSTEM. WILL HAVE
LINGER SHOWERS ON FRIDAY AS THE LOW PRESSURE SYSTEM MOVES OFF THE
EAST. ON SATURDAY...THE REGION WILL BE UNDER CYCLONIC FLOW. THE
HIGH WILL SHIFT EASTWARD ACROSS THE REGION AND OFFSHORE EARLY NEXT
WEEK. SATURDAY IS EXPECTED TO BE THE COOLEST DAY WITH HIGHS MAINLY
IN THE MID 50S TO MID 60S...AROUND 10 DEGREE BELOW NORMAL.
TEMPERATURES WILL GRADUALLY MODERATE AS THE HIGH SHIFTS TO THE EAST
WITH NEAR SEASONABLE TEMPERATURES FOR MONDAY.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK
VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND
EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON
MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY.
AT THIS TIME...NIGHTTIME LOWS FRIDAY NIGHT/SATURDAY MORNING AND
SATURDAY NIGHT/SUNDAY MORNING ARE EXPECTED TO BE IN THE 40S IN THE
VALLEYS AND 30S ACROSS THE HIGHER TERRAIN. WITH THE EXPANSION OF
THE GROWING SEASON BY THIS TIME FROST ADVISORIES WOULD BE LIKELY
NEEDED FOR THE HIGHER TERRAIN. TEMPERATURES ACROSS THE SOUTHERN
ADIRONDACKS COULD BE COLDER WHICH WOULD LEAD TO THE NEED FOR A
FREEZE WARNING.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD
CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT
07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR
CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED
THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN
KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF
THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN.
ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF
MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW
1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD
SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000
FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES
THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND
TRENDS CHANGE.
VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z
UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING.
MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE
LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE
THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE
TOMORROW AFTERNOON AND EVENING.
WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE
AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO
SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD
BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING.
OUTLOOK...
WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN.
WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF
AND KPOU CHC -SHRA/-TSRA.
THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL
CONTINUE INTO FRIDAY.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON.
WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING
SOUTHWEST AROUND 10MPH THURSDAY.
&&
.HYDROLOGY...
PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE
WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN
THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN
FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN
BANK RISES ARE LIKELY IN LARGER RIVERS.
3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT
THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY.
DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS...
BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST
THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS
WILL THIS AFTERNOON INTO THURSDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...SNYDER
SHORT TERM...SNYDER
LONG TERM...IAA/NAS
AVIATION...NAS
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
146 AM EDT WED MAY 22 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO THE AREA OVERNIGHT...THEN
DISSIPATE WEDNESDAY MORNING. A COLD FRONT WILL THEN SLOWLY
APPROACH FROM THE WEST...THEN PASS THROUGH THURSDAY NIGHT INTO
FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE
MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HAVE UPDATED GRIDS TO REFLECT CURRENT OBSERVATION TRENDS.
ADVECTION FOG/STRATUS EXPANDING INTO ERN-MOST LONG ISLAND SOUND
AND NEARBY LAND AREAS. WILL CONTINUE WITH DENSE FOG ADVY FOR THE
FORKS OF LONG ISLAND AND COASTAL SE CT...WITH PATCHY FOG
ELSEWHERE.
WATCHING LINE OF CONVECTION OVER CENTRAL NY STATE...WHICH THE RA
AND HRRR SUGGEST COULD MAKE A RIGHT TURN TOWARD THE CWA OVERNIGHT
INTO EARLY WED MORNING. CONVECTION APPEARS OUTFLOW-DOMINATED
WHICH SUGGESTS EVENTUAL WEAKENING. HOWEVER...SINCE THAT OUTFLOW IS
SOMEWHAT ALIGNED WITH THE BULK 0-3 KM SHEAR...SOME REDEVELOPMENT
COULD OCCUR CLOSER TO THE HUDSON VALLEY AND INTERIOR SW CT LATE
TONIGHT...SO HAVE CARRIED A SLIGHT CHANCE POP FOR ALL AREAS LATE
TONIGHT INTO WED MORNING.
BACK DOOR FRONT ADVANCING WWD INTO SOUTHERN CT AND EASTERN LONG
ISLAND WILL LEAD TO A COOLER NIGHT THAN ORIGINALLY FORECAST...WITH
LOWER 55-60. IT WILL HOWEVER REMAIN WARM AND MUGGY OVER THE
HUDSON VALLEY...NYC METRO AND LONG ISLAND...WITH LOWS IN THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
LOOKS LIKE A SIMILAR DAY ON WEDNESDAY AS RIDGE SLOWLY SHIFTS
EAST. BACK DOOR COLD FRONT SHOULD QUICKLY WASH OUT WITH DAYTIME
HEATING...AND MORNING FOG AND STRATUS WILL GIVE WAY TO AT LEAST
PARTIAL SUNSHINE. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY
MARGINAL INSTABILITY IN PLACE...LESS THAN TODAY. HIGHS IN THE MID
80S...EXCEPT ALONG THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY TRANSLATES
EAST THROUGH THE END OF THE WEEK AND THEN OFFSHORE BY THE WEEKEND.
INTERACTION WITH SHORT WAVE ENERGY IN THE NORTHERN BRANCH OF THE
POLAR JET ACROSS EASTERN CANADA WILL AMPLIFY THE TROUGH ACROSS THE
OH VALLEY AND MID ATLANTIC STATES. THIS AMPLIFICATION RESULTS IN
TIMING ISSUES AMONGST THE GLOBAL MODELS...WITH THE OPERATIONAL 12Z
GFS THE SLOWEST AT THE WESTERN END OF THE ENVELOPE. THE ECMWF AND
GGEM ARE THE QUICKEST WITH SWINGING THE FRONT ACROSS THE COAST BY
FRI MORNING. IN FACT...THE GFS CONTINUES TO BECOME MUCH SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW CLOSES OFF
APPROACHING THE MID ATLANTIC STATES...TAKING ON A NEGATIVE TILT
MUCH CLOSER TO THE COAST. THIS WOULD RESULT IN A PROLONGED PERIOD
OF POST-FRONTAL RAIN INTO SAT. PREFERENCE AT THIS TIME WAS TO LEAN
TOWARD THE FASTER MODEL CONSENSUS WITH PCPN SHUTTING DOWN FRI
AFT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO
SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER.
AS FOR THE SENSIBLE WEATHER...COLD FRONT APPROACHES FROM THE WEST
THU...PASSING ACROSS THE REGION THU NIGHT INTO FRI. HIGH PW
VALUES AND MODERATE INSTABILITY WILL LEAD TO THE DEVELOPMENT OF
WIDESPREAD SHOWERS AND THUNDERSTORMS THAT WORK WEST TO EAST
DURING THIS TIME. THE ISOLATED SEVERE THREAT APPEARS LOW AT THIS
TIME WITH THE LOW-LEVEL JET DISPLACED EAST OF THE AREA AND
MARGINAL DEEP LAYER SHEAR. UNIDIRECTIONAL WIND PROFILES SUPPORT
SOME BOWING LINE SEGMENTS WITH GUSTY WINDS. WET-BULB ZERO VALUES ARE
WARM...SUPPORTING ONLY SMALL HAIL. THE MAIN THREAT LOOKS TO BE
THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY IF THE UPPER FLOW
BACKS FURTHER WITH THE AMPLIFICATION OF THE UPPER TROF TO THE
WEST. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH
LOCALIZED HIGHER AMOUNTS.
A DRIER NW FLOW SET UPS FRI NIGHT WITH STRONG COLD ADVECTION. HIGH
PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC
STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES
BELOW SEASONABLE LEVELS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
LITTLE CHANGE TO THE AVIATION FORECAST AS A NEARLY STATIONARY
FRONT WILL REMAIN NORTH ACROSS THE LOWER HUDSON VALLEY WHILE
FARTHER EAST THE FRONT WAS MOVING WESTWARD AS A COLD FRONT. THE
FRONT WILL MAKE IT TO AROUND NEW YORK CITY BY MORNING BEFORE
MOVING BACK NORTH DURING THE MORNING.
STRATUS AND FOG HAS BEGUN TO MOVE IN FROM THE EAST AND WILL MOVE
INTO THE NYC AREA TERMINALS FROM 08Z TO 10Z. CEILINGS AND
VISIBILITIES BECOME IFR AND AS LOW AS VLIFR AT THE COASTAL
TERMINALS ESPECIALLY AFTER 07Z. CONDITIONS IMPROVE EARLY WEDNESDAY
MORNING...13Z TO 15Z. TIMING OF IMPROVEMENT AND CONDITIONS
UNCERTAIN. WIND WILL BE LIGHT FROM THE SOUTH THROUGH THE NIGHT
THEN INCREASE TO 10 TO 15 KT DURING WEDNESDAY.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER 16Z MAINLY NORTH
AND WEST OF THE NEW YORK TERMINALS.
.OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.WEDNESDAY NIGHT...SCT SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG
AND STRATUS.
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN
FOG AND STRATUS.
.SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR
WITH NW WINDS INCREASING TO 20-30KT.
.SUNDAY...VFR WITH NW WINDS 20-25KT.
&&
.MARINE...
DENSE FOG BEGINNING TO DEVELOP ACROSS THE EASTERN WATERS.
THIS ADVECTION FOG IS EXPECTED TO EXPAND BACK WEST OVERNIGHT.
SHALLOW BACK DOOR COLD FRONT SHOULD BRING SE-E WINDS OVERNIGHT TO
THE ERN-MOST OCEAN WATERS...ALSO LONG ISLAND SOUND AND THE BAYS OF
LONG ISLAND. OTHERWISE...S-SW SUB SCA WINDS SHOULD CONTINUE
THROUGH WED NIGHT. SEAS SHOULD SLOWLY BUILD ON WED...BUT HAVE
UNDERCUT WAVEWATCH TO PREVENT REACHING SCA CRITERIA UNTIL
WEDNESDAY NIGHT. THINKING WITH STRONG INVERSION THAT WIND FORCING
WAS OVERDONE IN THE WW3 FORECAST.
A COLD FRONT WILL MOVE ACROSS THE AREA WATERS FRIDAY MORNING...WITH
HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS COULD BE BELOW
SCA LEVELS BY FRIDAY MORNING...WITH SEAS ON THE OCEAN REMAINING
ABOVE SCA CRITERIA THROUGH MUCH SATURDAY MORNING. UNDERCUT
WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE
FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY
WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS.
&&
.HYDROLOGY...
SLIGHT CHANCE FOR SOME SHOWERS/TSTMS TO ENTER THE AREA LATE
TONIGHT INTO EARLY WED MORNING. SCT SHOWERS/TSTMS LATER WED WILL
BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST
CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD
BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMTS IN TSTMS.
A MORE ORGANIZED EVENT LATE THU INTO FRI SHOULD PRODUCE AVERAGE
BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER
AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS
WHICH COULD RESULT IN FLASH FLOODING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ011-012.
NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ079-081.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ330-340-
345-350-353.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1232 AM EDT WED MAY 22 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL MOVE INTO THE AREA OVERNIGHT...THEN
DISSIPATE WEDNESDAY MORNING. A COLD FRONT WILL THEN SLOWLY
APPROACH FROM THE WEST...THEN PASS THROUGH THURSDAY NIGHT INTO
FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE
MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HAVE UPDATED GRIDS TO REFLECT CURRENT OBSERVATION TRENDS.
ADVECTION FOG/STRATUS EXPANDING INTO ERN-MOST LONG ISLAND SOUND
AND NEARBY LAND AREAS. WILL CONTINUE WITH DENSE FOG ADVY FOR THE
FORKS OF LONG ISLAND AND COASTAL SE CT...WITH PATCHY FOG
ELSEWHERE.
WATCHING LINE OF CONVECTION OVER CENTRAL NY STATE...WHICH THE RA
AND HRRR SUGGEST COULD MAKE A RIGHT TURN TOWARD THE CWA OVERNIGHT
INTO EARLY WED MORNING. CONVECTION APPEARS OUTFLOW-DOMINATED
WHICH SUGGESTS EVENTUAL WEAKENING. HOWEVER...SINCE THAT OUTFLOW IS
SOMEWHAT ALIGNED WITH THE BULK 0-3 KM SHEAR...SOME REDEVELOPMENT
COULD OCCUR CLOSER TO THE HUDSON VALLEY AND INTERIOR SW CT LATE
TONIGHT...SO HAVE CARRIED A SLIGHT CHANCE POP FOR ALL AREAS LATE
TONIGHT INTO WED MORNING.
BACK DOOR FRONT ADVANCING WWD INTO SOUTHERN CT AND EASTERN LONG
ISLAND WILL LEAD TO A COOLER NIGHT THAN ORIGINALLY FORECAST...WITH
LOWER 55-60. IT WILL HOWEVER REMAIN WARM AND MUGGY OVER THE
HUDSON VALLEY...NYC METRO AND LONG ISLAND...WITH LOWS IN THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
LOOKS LIKE A SIMILAR DAY ON WEDNESDAY AS RIDGE SLOWLY SHIFTS
EAST. BACK DOOR COLD FRONT SHOULD QUICKLY WASH OUT WITH DAYTIME
HEATING...AND MORNING FOG AND STRATUS WILL GIVE WAY TO AT LEAST
PARTIAL SUNSHINE. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY
MARGINAL INSTABILITY IN PLACE...LESS THAN TODAY. HIGHS IN THE MID
80S...EXCEPT ALONG THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY TRANSLATES
EAST THROUGH THE END OF THE WEEK AND THEN OFFSHORE BY THE WEEKEND.
INTERACTION WITH SHORT WAVE ENERGY IN THE NORTHERN BRANCH OF THE
POLAR JET ACROSS EASTERN CANADA WILL AMPLIFY THE TROUGH ACROSS THE
OH VALLEY AND MID ATLANTIC STATES. THIS AMPLIFICATION RESULTS IN
TIMING ISSUES AMONGST THE GLOBAL MODELS...WITH THE OPERATIONAL 12Z
GFS THE SLOWEST AT THE WESTERN END OF THE ENVELOPE. THE ECMWF AND
GGEM ARE THE QUICKEST WITH SWINGING THE FRONT ACROSS THE COAST BY
FRI MORNING. IN FACT...THE GFS CONTINUES TO BECOME MUCH SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW CLOSES OFF
APPROACHING THE MID ATLANTIC STATES...TAKING ON A NEGATIVE TILT
MUCH CLOSER TO THE COAST. THIS WOULD RESULT IN A PROLONGED PERIOD
OF POST-FRONTAL RAIN INTO SAT. PREFERENCE AT THIS TIME WAS TO LEAN
TOWARD THE FASTER MODEL CONSENSUS WITH PCPN SHUTTING DOWN FRI
AFT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO
SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER.
AS FOR THE SENSIBLE WEATHER...COLD FRONT APPROACHES FROM THE WEST
THU...PASSING ACROSS THE REGION THU NIGHT INTO FRI. HIGH PW
VALUES AND MODERATE INSTABILITY WILL LEAD TO THE DEVELOPMENT OF
WIDESPREAD SHOWERS AND THUNDERSTORMS THAT WORK WEST TO EAST
DURING THIS TIME. THE ISOLATED SEVERE THREAT APPEARS LOW AT THIS
TIME WITH THE LOW-LEVEL JET DISPLACED EAST OF THE AREA AND
MARGINAL DEEP LAYER SHEAR. UNIDIRECTIONAL WIND PROFILES SUPPORT
SOME BOWING LINE SEGMENTS WITH GUSTY WINDS. WET-BULB ZERO VALUES ARE
WARM...SUPPORTING ONLY SMALL HAIL. THE MAIN THREAT LOOKS TO BE
THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY IF THE UPPER FLOW
BACKS FURTHER WITH THE AMPLIFICATION OF THE UPPER TROF TO THE
WEST. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH
LOCALIZED HIGHER AMOUNTS.
A DRIER NW FLOW SET UPS FRI NIGHT WITH STRONG COLD ADVECTION. HIGH
PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC
STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES
BELOW SEASONABLE LEVELS.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT WILL REMAIN NORTH ACROSS THE LOWER HUDSON
VALLEY WHILE FARTHER EAST THE FRONT WAS MOVING WESTWARD AS A COLD
FRONT. THE FRONT WILL MAKE IT TO AROUND NEW YORK CITY BY MORNING
BEFORE MOVING BACK NORTH DURING THE MORNING.
STRATUS AND FOG WAS BEGINNING TO MOVE IN FROM THE EAST AND WILL MOVE
INTO THE NYC AREA TERMINALS FROM 08Z TO 10Z. CEILINGS AND
VISIBILITIES BECOME IFR AND AS LOW AS VLIFR AT THE COASTAL TERMINALS
ESPECIALLY AFTER 07Z. CONDITIONS IMPROVE EARLY WEDNESDAY
MORNING...13Z TO 15Z. TIMING OF IMPROVEMENT AND CONDITIONS
UNCERTAIN. WIND WILL BE LIGHT FROM THE SOUTH THROUGH THE NIGHT THEN
INCREASE TO 10 TO 15 KT DURING WEDNESDAY.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER 16Z MAINLY NORTH
AND WEST OF THE NEW YORK TERMINALS.
.OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
.WEDNESDAY NIGHT...SCT SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG
AND STRATUS.
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN
FOG AND STRATUS.
.SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR
WITH NW WINDS INCREASING TO 20-30KT.
.SUNDAY...VFR WITH NW WINDS 20-25KT.
&&
.MARINE...
DENSE FOG BEGINNING TO DEVELOP ACROSS THE EASTERN WATERS.
THIS ADVECTION FOG IS EXPECTED TO EXPAND BACK WEST OVERNIGHT.
SHALLOW BACK DOOR COLD FRONT SHOULD BRING SE-E WINDS OVERNIGHT TO
THE ERN-MOST OCEAN WATERS...ALSO LONG ISLAND SOUND AND THE BAYS OF
LONG ISLAND. OTHERWISE...S-SW SUB SCA WINDS SHOULD CONTINUE
THROUGH WED NIGHT. SEAS SHOULD SLOWLY BUILD ON WED...BUT HAVE
UNDERCUT WAVEWATCH TO PREVENT REACHING SCA CRITERIA UNTIL
WEDNESDAY NIGHT. THINKING WITH STRONG INVERSION THAT WIND FORCING
WAS OVERDONE IN THE WW3 FORECAST.
A COLD FRONT WILL MOVE ACROSS THE AREA WATERS FRIDAY MORNING...WITH
HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS COULD BE BELOW
SCA LEVELS BY FRIDAY MORNING...WITH SEAS ON THE OCEAN REMAINING
ABOVE SCA CRITERIA THROUGH MUCH SATURDAY MORNING. UNDERCUT
WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE
FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY
WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS.
&&
.HYDROLOGY...
SLIGHT CHANCE FOR SOME SHOWERS/TSTMS TO ENTER THE AREA LATE
TONIGHT INTO EARLY WED MORNING. SCT SHOWERS/TSTMS LATER WED WILL
BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST
CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD
BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMTS IN TSTMS.
A MORE ORGANIZED EVENT LATE THU INTO FRI SHOULD PRODUCE AVERAGE
BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER
AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS
WHICH COULD RESULT IN FLASH FLOODING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ011-012.
NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ079-081.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ330-340-
345-350-353.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
523 AM EDT WED MAY 22 2013
.UPDATE...SHOWERS HAVE RECENTLY INCREASED OVER THE ATLANTIC WITH
MOVEMENT ONSHORE THE COAST. SOME ARE BECOMING HEAVY WITH EVEN A
THUNDERSTORM IN FAR SOUTH MIAMI-DADE WITH A FEW LIGHTNING STRIKES
DETECTED. GIVEN THE RADAR TRENDS AND HRRR DEPICTION, HAVE INCREASED
WEATHER TO NUMEROUS FOR ALL OF THE EAST COAST AND INTERIOR THROUGH
THIS AFTERNOON. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 356 AM EDT WED MAY 22 2013/
DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL
GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE
GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY
TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE
FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST
PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH
LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT
AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM
BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING
THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN
THE HAZARDOUS WEATHER OUTLOOK.
THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS
AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT
OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND
WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT
BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED
AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND
ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO
FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH
BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT
AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN
OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG
HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT
LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO
THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL
NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE
SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND.
FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO
SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND
THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE
OFFING.
MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER
LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN
NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING
INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING
SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND.
FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE
CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 72 87 73 / 60 30 30 20
FORT LAUDERDALE 85 74 88 76 / 60 20 30 20
MIAMI 87 74 89 76 / 60 20 30 20
NAPLES 85 71 86 72 / 40 20 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
356 AM EDT WED MAY 22 2013
.DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL
GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE
GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY
TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE
FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST
PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH
LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT
AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM
BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING
THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN
THE HAZARDOUS WEATHER OUTLOOK.
THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS
AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT
OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND
WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT
BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED
AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND
ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO
FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH
BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT
AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN
OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG
HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT
LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO
THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL
NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE
SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND.
FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO
SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND
THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE
OFFING.
&&
.MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER
LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN
NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING
INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING
SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND.
&&
.FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE
CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 72 87 73 / 60 30 30 20
FORT LAUDERDALE 85 74 88 76 / 50 20 30 20
MIAMI 87 74 89 76 / 50 20 30 20
NAPLES 85 71 86 72 / 40 20 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/GREGORIA
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
144 AM EDT WED MAY 22 2013
.AVIATION...
FOR THE SHORT TERM...PASSING SHOWERS WILL LIKELY AFFECT ALL EAST
COAST TERMINALS EXCEPT KPBI FOR THE NEXT FEW HOURS. LOW CONFIDENCE
OF AN ISOLATED THUNDERSTORM OCCURRING IN THIS PERIOD WITH BRIEF
PERIODS OF MVFR CEILINGS POSSIBLE WITH PASSING SHOWERS. BY LATE
WEDNESDAY MORNING AND INTO THE AFTERNOON HOURS...THE COMBINATION
OF THE WEST AND EAST COAST SEA BREEZES...A LINGERING UPPER LEVEL LOW
AND AVAILABLE MOISTURE SHOULD RESULT IN VCTS ALL TERMINALS AROUND
15Z.
60
&&
.PREV DISCUSSION... /ISSUED 949 PM EDT TUE MAY 21 2013/
UPDATE...
UPDATED PRODUCTS EARLIER TO CANCEL FLOOD WATCH BUT HAVE KEPT SCT
POPS GOING THROUGH THE NIGHT. IT APPEARS THAT THE HEAVY RAIN
THREAT IS OVER, BUT WITH THE UPPER LOW STILL IN THE VICINITY
CANNOT RULE OUT A POSSIBLE STORM JUST ABOUT ANYWHERE AT ANY TIME.
LOW LEVEL FLOW CONTINUES SOUTHEASTERLY SO THE GREATEST THREAT WILL
BE THE SOUTHEAST COAST ESPECIALLY IF A LITTLE BIT OF CONVERGENCE
CAN SET UP WITH LESSENING FLOW NEAR THE COAST. THE HRRR CYCLE
SEEMS TO CHANGE EVERY TWO TO THREE HOURS BUT THE LATEST RUN IS
SHOWING QUIET ACTIVITY THROUGH 06Z BUT THE EARLIER RUN HAD SHOWN A
FLARE UP OF CONVECTION LATER TONIGHT ALTHOUGH NOT WIDESPREAD.
KOB
PREV DISCUSSION... /ISSUED 758 PM EDT TUE MAY 21 2013/
AVIATION...
THE SHOWERS AND SHOULD COME TO AN END OVER SOUTH FLORIDA BY 03Z
TONIGHT AND REMAIN DRY THROUGH 15Z ON WEDNESDAY. SO WILL KEEP VCSH
IN THE ALL OF SOUTH FLORIDA TAF SITES UNTIL 03Z...BEFORE GOING DRY
FOR REST OF TONIGHT. THE WINDS TONIGHT WILL ALSO REMAIN IN A
EASTERLY DIRECTION AT 5 KNOTS OR LESS TONIGHT AT ALL OF THE TAF
SITES.
ON WEDNESDAY...THE WEATHER WILL REMAIN DRY UNTIL 15Z BEFORE
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP OVER SOUTH FLORIDA. SO
WILL PUT IN A VCTS FOR ALL OF SOUTH FLORIDA TAF SITES AFTER 15Z ON
WEDNESDAY. THE EASTERLY WINDS WILL ALSO INCREASE TO AROUND 10
KNOTS WEDNESDAY MORNING AT ALL OF THE TAF SITES AND REMAIN
EASTERLY AT 10 KNOTS THROUGH WEDNESDAY AFTERNOON. THE ONLY
EXCEPTION TO THIS IS AT KAPF TAF SITE...WHERE THE WIND DIRECTION
WILL BECOME WESTERLY DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITION TONIGHT
INTO WEDNESDAY AT ALL OF THE TAF SITES.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 245 PM EDT TUE MAY 21 2013/
FLOOD WATCH IN EFFECT UNTIL 10 PM EDT THIS EVENING FOR EAST
COAST METRO AREAS...
SHORT TERM...
THE EAST AND WEST COAST SEA BREEZES WERE DEVELOPING ALONG BOTH
COASTS OF SOUTH FLORIDA EARLY THIS AFTERNOON. THESE SEA BREEZES
WILL PUSH SLOWLY INLAND THROUGH THE REST OF THE AFTERNOON HOURS
HELPING TO GENERATE SHOWERS AND THUNDERSTORMS OVER THE AREA. THE
STORMS WILL BE SLOW MOVING THIS AFTERNOON INTO THIS EVENING...AS
THE STEERING FLOW WILL BE LIGHT FROM THE SOUTH AHEAD OF A TROUGH
OF LOW PRESSURE LOCATED OVER THE EASTERN GULF OF MEXICO.
THE GPS-MET SATELLITE IMAGES WHERE SHOWING THE PWAT VALUES TO BE
BETWEEN 1.6 TO 1.7 INCHES EARLY THIS AFTERNOON OVER SOUTH
FLORIDA. THE AVERAGE PWAT VALUE FOR THIS TIME OF YEAR IS AROUND
1.35 INCHES FOR SOUTH FLORIDA. THIS WILL ALLOW FOR HEAVY RAINFALL
OVER SOUTH FLORIDA THIS AFTERNOON INTO THIS EVENING. SO, WILL
CONTINUE TO MENTION HEAVY RAINFALL IN THE FORECAST FOR SOUTH
FLORIDA FOR THIS AFTERNOON INTO THIS EVENING.
THE HEAVY RAINFALL FROM THE STORMS THIS AFTERNOON INTO THIS
EVENING OVER THE EAST COAST METRO AREAS WILL ALLOW FOR SOME
FLOODING TO OCCUR...AS THE GROUNDS ARE VERY SATURATED FROM THE
HEAVY RAINFALL FROM THE STORMS YESTERDAY. THEREFORE...THE FLOOD
WATCH WILL REMAIN IN PLACE OVER THE EAST COAST METRO AREAS THROUGH
LATE THIS EVENING.
THE MID TO UPPER LEVEL TROUGH OVER THE EASTERN GULF OF MEXICO WILL
MOVE EAST TONIGHT THROUGH THE FLORIDA PENINSULA AS THE UPPER LEVEL
LOW OVER NORTHERN FLORIDA MOVES EAST INTO THE WESTERN ATLANTIC
WATERS. THIS WILL ALLOW FOR THE DEEPER MOISTURE OVER SOUTH FLORIDA
TO MOVE EAST INTO THE WESTERN ATLANTIC WATERS ON WEDNESDAY WHICH
WILL ALLOW FOR SOME DRIER AIR TO WORK INTO THE AREA FROM THE
CENTRAL GULF OF MEXICO. THE DRIER AIR WILL STICK AROUND ON
THURSDAY OVER SOUTH FLORIDA. HOWEVER...THERE WILL STILL BE ENOUGH
MOISTURE OVER SOUTH FLORIDA EACH DAY TO ALLOW FOR SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE AREA ON WEDNESDAY
AND THURSDAY ALONG THE SEA BREEZES WITH THE BEST COVERAGE OVER THE
INTERIOR AREAS.
LONG TERM...
A COLD FRONT LOCATED OVER THE CENTRAL UNITED STATES IS FORECAST BY
THE LONG RANGE MODELS TO MOVE SOUTHEAST AND THROUGH SOUTH FLORIDA
EARLY THIS WEEKEND. HIGH PRESSURE SHOULD THEN BUILD INTO THE AREA
FROM THE NORTH LATE THIS WEEKEND INTO EARLY NEXT WEEK. THIS WILL
ALLOW FOR MUCH DRIER AIR TO WORK INTO THE AREA FROM THE NORTH FOR
LATE THIS WEEKEND INTO EARLY NEXT WEEK. SO WILL KEEP A SLIGHT
CHANCE OF POPS OVER SOUTH FLORIDA FOR THE EARLY PART OF THIS
WEEKEND BEFORE GOING DRY FOR THE SECOND HALF OF THIS WEEKEND INTO
EARLY NEXT WEEK.
AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND
PUSH SLOWLY NORTH THROUGH THE AFTERNOON HOURS. SO KEPT VCTS FOR ALL
TAF SITES THROUGH THE AFTERNOON. A FEW SHOWERS MAY MOVE NEAR THE
EAST COAST TAF SITES OVERNIGHT. AN UPPER LEVEL TROUGH WILL SHIFT
EAST TONIGHT INTO WEDNESDAY...PUSHING THE BEST DYNAMICS OVER THE
ATLANTIC WATERS. SO THUNDERSTORM ACTIVITY IS EXPECTED TO START NEAR
THE END OF THE TAF PERIOD ALONG THE SEA BREEZE BOUNDARIES.
MARINE...
THE WINDS WILL BE SOUTHERLY BELOW 10 KNOTS THROUGH LATE THIS
WEEK...BEFORE INCREASING TO BREEZY CONDITIONS FROM THE NORTHEAST
DIRECTION FOR THIS WEEKEND. THIS WILL ALLOW FOR THE SEAS TO REMAIN
BELOW 6 FEET FOR BOTH THE ATLANTIC AND GULF WATERS OF SOUTH
FLORIDA THROUGH LATE THIS WEEK INTO EARLY THIS WEEKEND...BEFORE
INCREASING TO AROUND 6 FEET IN THE GULF STREAM WATERS OF THE
ATLANTIC BY LATE THIS WEEKEND.
FIRE WEATHER...
THE RELATIVE HUMIDITY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL
VALUE OVER SOUTH FLORIDA THROUGH REST OF THIS WEEK. SO NO PROBLEMS
ARE EXPECTED WITH THE FIRE WEATHER OVER SOUTH FLORIDA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 74 88 73 / 50 40 30 30
FORT LAUDERDALE 86 77 88 76 / 50 30 30 20
MIAMI 87 76 89 75 / 50 30 30 20
NAPLES 87 71 88 71 / 40 20 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS TOPEKA KS
326 AM CDT WED MAY 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CDT WED MAY 22 2013
NORTHWEST FLOW BEGINNING TO TAKE OVER THE LOCAL AREA AS THE
SLOW-MOVING NORTHERN PLAINS SYSTEM INCHES EASTWARD. A WEAK POTENTIAL
VORTICITY ANOMALY WAS ROTATING SOUTHEAST INTO NORTHEAST KANSAS IN
RECENT HOURS WITH ONLY SOME HIGH CLOUDS RESULTING IN SOMEWHAT DRY
MID LEVELS. PERIODIC LOWER CLOUDS ALSO MAKING THEIR WAY SOUTHEAST
INTO KANSAS.
LOW-MID LEVEL MOISTURE WILL BE ON THE INCREASE TODAY...THOUGH
FORCING FOR PRECIPITATION WILL BE LACKING ON THE SOUTHWEST SIDE OF
THE SYSTEM AND IN DEEP BUT WEAK ISENTROPIC DOWNGLIDE. THE INCREASED
CLOUDS AND SOME COLD AIR ADVECTION ON NORTHWEST WINDS SHOULD KEEP
TEMPS A BIT COOLER THAN TUESDAY. SOME CLEARING SHOULD TAKE PLACE
TONIGHT AS RIDGING BEGINS TO DEVELOP THROUGH THE TROPOSPHERE WITH
ENOUGH WIND TO KEEP FOG IN CHECK.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 307 AM CDT WED MAY 22 2013
THURS THRU SAT...COOL HIGH PRESSURE CONTINUES TO PUSH SOUTH AND EAST
OF THE AREA WED NIGHT THROUGH THURSDAY...AND ANTICIPATE ANOTHER
DAY OF BELOW NORMAL HIGHS IN THE UPPER 60S NORTH TO MID 70S SOUTH.
FAR WESTERN AREAS MAY SEE A SLIGHT CHANCE FOR SOME LATE NIGHT POPS
INTO FRIDAY MORNING. CHANCES FOR PRECIPITATION IN THE AREA START TO
INCREASE ON FRIDAY AS FRONT ASSOCIATED WITH NORTHERN ROCKIES
SHORTWAVE SENDS TRAILING PRECIP INTO THE HIGH PLAINS AND MAY
DEVELOP PRECIP SOUTHWARD ALONG THE MID LEVEL FRONT ON THE HIGH
PLAINS. HAVE SPREAD POPS WEST TO EAST THROUGH FRIDAY...CONTINUING
INTO FRIDAY NIGHT AS LLJ VEERS NE OFF THE HIGH PLAINS AGAIN AND
BRINGS A SLIGHTLY HIGHER CHANCE FOR RAIN IN THE OVERNIGHT HOURS.
THIS WAVE PROPAGATES EAST SE THROUGH THE RIDGE AXIS OVER THE STATE
AND AS PROGGED WOULD LINGER STORM CHANCES INTO SATURDAY AFTERNOON.
DEPENDING ON WHERE BOUNDARIES ASSOCIATED WITH THAT SYSTEM REMAIN
AS THE LLJ INCREASES AGAIN EARLY SUNDAY MORNING...WOULD EXPECT
ANOTHER ROUND OF PRECIPITATION SOMEWHERE IN NE KS.
SUN-TUES...PRECIP CHANCES REMAIN SOMEWHAT ERRATIC AND DIFFICULT TO
TIME AS SMALL ROUNDS OF SW ENERGY ROTATE NE OUT OF THE SWRN TROF.
MOISTURE AND INSTABILITY ARE IN PLACE TO RESPOND TO THESE
WAVES...AS WELL AS NIGHTLY CYCLE OF THE LOW LEVEL JET. HAVE PRECIP
THROUGHOUT THE PERIOD WITH HIGHER CHANCES IN THE OVERNIGHT HOURS
AS A RESULT. AS WINDS COME BACK AROUND FROM THE SOUTH...TEMPERATURES
SHOULD WARM BACK TOWARD THE LOWER 80S FOR THE EXTENDED PORTION OF
THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM CDT TUE MAY 21 2013
LATEST OBS SHOW SOME MVFR CIGS TO THE NORTH ACROSS NEB. MODELS
CONTINUE TO SHOW THESE CIGS REMAINING JUST NORTH OF THE TERMINALS
WITH THE 00Z OBJECTIVE MOS GUIDANCE KEEPING CONDITIONS VFR.
THEREFORE WILL MAINTAIN PREV VFR FORECAST. THE RAP AND GFS SUGGEST
SOME DECENT MIXING WITH THE POTENTIAL FOR SOME SFC WIND GUSTS
THROUGH THE LATE MORNING AND AFTERNOON ALONG WITH A STRATOCU DECK
FORMING ABOVE 3 KFT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...67
AVIATION...WOLTERS
AREA FORECAST DISCUSSION...CORRECTED
NWS TOPEKA KS
1149 PM CDT TUE MAY 21 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 339 PM CDT TUE MAY 21 2013
UPPER LOW REMAINS ACROSS THE NORTHERN PLAINS WITH ENERGY ROTATING
AROUND THE BASE MOVING INTO NORTH CENTRAL NEBRASKA. A STRONG
SHORTWAVE WAS MOVING INTO WESTERN OKLAHOMA AT LATE AFTERNOON. MODELS
STILL SHOWING BEST FORCING (Q-VECTOR CONVERGENCE AND VORTICITY
ADVECTION) REMAINING TO THE SOUTH OF THE FORECAST AREA THIS EVENING.
SHORT RANGE HIGH RESOLUTION MODELS BREAK OUT SOME CONVECTION IN FAR
EAST CENTRAL KANSAS EARLY THIS EVENING AND WILL MAINTAIN SMALL
PRECIPITATION CHANCES FOR PARTS OF ANDERSON COUNTY THIS EVENING.
COLD ADVECTION ACROSS NORTHERN KANSAS WILL CONTINUE THROUGH THE
NIGHT WITH TEMPERATURES FALLING INTO THE UPPER 40S IN NORTH CENTRAL
KANSAS TO THE MID 50S IN EAST CENTRAL KANSAS.
CLOUDS WILL BE ON THE DECREASE WEDNESDAY MORNING AND EXPECT SOME
SCATTERED CUMULUS CLOUDS FOR MUCH OF THE AFTERNOON. COOL HIGH
PRESSURE WILL BUILD INTO NORTHEAST KANSAS WEDNESDAY AS THE UPPER
TROUGH MOVES INTO THE GREAT LAKES DURING THE DAY. TEMPERATURES WILL
BE COOLEST ACROSS THE FAR NORTH WITH HIGHS IN THE 60S WITH LOWER 70S
ACROSS THE SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 PM CDT TUE MAY 21 2013
WED NIGHT THROUGH THU NIGHT...THE UPPER TROUGH IN THE UPPER MS VALLEY
WILL SWING EASTWARD INTO THE GREAT LAKES AS THE HIGH PLAINS UPPER
RIDGE SHIFTS EASTWARD INTO THE EASTERN PLAINS. THIS WILL ALLOW FOR
THE DRY NORTH TO NORTHEASTERLY FLOW THROUGH 850MB TO PERSIST AND
KEEP ANY SIGNIFICANT MOISTURE AND/OR INSTABILITY TO THE SOUTH OF THE
COUNTY WARNING AREA UNTIL LATER THURSDAY NIGHT. THIS WHEN WEAK
THETA E/MOISTURE ADVECTION BEGINS ACROSS THE FAR WEST AND
SOUTHWESTERN PORTIONS OF THE CWA...SO WILL INTRODUCE A SLIGHT CHANCE
FOR THUNDERSTORMS AT THAT TIME. SEASONABLY COOL LOW TEMPERATURES IN
THE UPPER 40S AND LOWER 50S WEDNESDAY NIGHT WILL EDGE UP INTO THE LOW
TO MIDDLE 50S THURSDAY NIGHT WHILE HIGHS ON THURSDAY TOP OUT IN THE
LOW TO MIDDLE 70S.
FRI THROUGH TUESDAY...THE RIDGING ALOFT WILL SLOWLY TRANSLATE
EASTWARD INTO THE MO AND MS VALLEY AREAS OVER THE WEEKEND INTO EARLY
NEXT WEEK. THIS WILL TRANSITION THE FLOW ALOFT TO A MORE WEST AND
SOUTHWESTERLY DIRECTION. THIS WILL ALLOW FOR A LEE SIDE SFC
TROUGH/LOW IN THE CENTRAL HIGH PLAINS TO REMAIN ANCHORED THROUGH THE
PERIOD. AT THE SAME TIME...THE UPPER FLOW WILL LIKELY DIRECT A
SERIES OF WEAK SHORTWAVE TROUGHS OUT OF THE MAIN UPPER TROUGH IN THE
WESTERN CONUS OUT INTO THE CENTRAL PLAINS. MOISTURE RETURN WILL
CONTINUE/REMAIN IN PLACE THROUGH THE PERIOD...SO THE PASSAGE ANY OF
THE SHORTWAVE WILL HAVE THE POTENTIAL TO TRIGGER CONVECTION ACROSS
THE AREA THROUGH THE PERIOD. THIS FAR OUT IT REMAINS VERY DIFFICULT
TO PIN DOWN THE TIMING AND/OR AREAL EXTENT OF ANY CONVECTION AND
MESOSCALE FEATURES SUCH AS OUTFLOW BOUNDARIES FROM POSSIBLE MCS`S
EACH DAY WOULD ONLY COMPLICATE THE FCST. HAVE THEREFORE CONTINUED A
BROAD AND GENERAL FCST ON THE PRECIP POTENTIAL WITH HIGHS GENERALLY
IN THE 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM CDT TUE MAY 21 2013
LATEST OBS SHOW SOME MVFR CIGS TO THE NORTH ACROSS NEB. MODELS
CONTINUE TO SHOW THESE CIGS REMAINING JUST NORTH OF THE TERMINALS
WITH THE 00Z OBJECTIVE MOS GUIDANCE KEEPING CONDITIONS VFR.
THEREFORE WILL MAINTAIN PREV VFR FORECAST. THE RAP AND GFS SUGGEST
SOME DECENT MIXING WITH THE POTENTIAL FOR SOME SFC WIND GUSTS
THROUGH THE LATE MORNING AND AFTERNOON ALONG WITH A STRATOCU DECK
FORMING ABOVE 3 KFT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...53
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1136 PM CDT TUE MAY 21 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 339 PM CDT TUE MAY 21 2013
UPPER LOW REMAINS ACROSS THE NORTHERN PLAINS WITH ENERGY ROTATING
AROUND THE BASE MOVING INTO NORTH CENTRAL NEBRASKA. A STRONG
SHORTWAVE WAS MOVING INTO WESTERN OKLAHOMA AT LATE AFTERNOON. MODELS
STILL SHOWING BEST FORCING (Q-VECTOR CONVERGENCE AND VORTICITY
ADVECTION) REMAINING TO THE SOUTH OF THE FORECAST AREA THIS EVENING.
SHORT RANGE HIGH RESOLUTION MODELS BREAK OUT SOME CONVECTION IN FAR
EAST CENTRAL KANSAS EARLY THIS EVENING AND WILL MAINTAIN SMALL
PRECIPITATION CHANCES FOR PARTS OF ANDERSON COUNTY THIS EVENING.
COLD ADVECTION ACROSS NORTHERN KANSAS WILL CONTINUE THROUGH THE
NIGHT WITH TEMPERATURES FALLING INTO THE UPPER 40S IN NORTH CENTRAL
KANSAS TO THE MID 50S IN EAST CENTRAL KANSAS.
CLOUDS WILL BE ON THE DECREASE WEDNESDAY MORNING AND EXPECT SOME
SCATTERED CUMULUS CLOUDS FOR MUCH OF THE AFTERNOON. COOL HIGH
PRESSURE WILL BUILD INTO NORTHEAST KANSAS WEDNESDAY AS THE UPPER
TROUGH MOVES INTO THE GREAT LAKES DURING THE DAY. TEMPERATURES WILL
BE COOLEST ACROSS THE FAR NORTH WITH HIGHS IN THE 60S WITH LOWER 70S
ACROSS THE SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 PM CDT TUE MAY 21 2013
WED NIGHT THROUGH THU NIGHT...THE UPPER TROUGH IN THE UPPER MS VALLEY
WILL SWING EASTWARD INTO THE GREAT LAKES AS THE HIGH PLAINS UPPER
RIDGE SHIFTS EASTWARD INTO THE EASTERN PLAINS. THIS WILL ALLOW FOR
THE DRY NORTH TO NORTHEASTERLY FLOW THROUGH 850MB TO PERSIST AND
KEEP ANY SIGNIFICANT MOISTURE AND/OR INSTABILITY TO THE SOUTH OF THE
COUNTY WARNING AREA UNTIL LATER THURSDAY NIGHT. THIS WHEN WEAK
THETA E/MOISTURE ADVECTION BEGINS ACROSS THE FAR WEST AND
SOUTHWESTERN PORTIONS OF THE CWA...SO WILL INTRODUCE A SLIGHT CHANCE
FOR THUNDERSTORMS AT THAT TIME. SEASONABLY COOL LOW TEMPERATURES IN
THE UPPER 40S AND LOWER 50S WEDNESDAY NIGHT WILL EDGE UP INTO THE LOW
TO MIDDLE 50S THURSDAY NIGHT WHILE HIGHS ON THURSDAY TOP OUT IN THE
LOW TO MIDDLE 70S.
FRI THROUGH TUESDAY...THE RIDGING ALOFT WILL SLOWLY TRANSLATE
EASTWARD INTO THE MO AND MS VALLEY AREAS OVER THE WEEKEND INTO EARLY
NEXT WEEK. THIS WILL TRANSITION THE FLOW ALOFT TO A MORE WEST AND
SOUTHWESTERLY DIRECTION. THIS WILL ALLOW FOR A LEE SIDE SFC
TROUGH/LOW IN THE CENTRAL HIGH PLAINS TO REMAIN ANCHORED THROUGH THE
PERIOD. AT THE SAME TIME...THE UPPER FLOW WILL LIKELY DIRECT A
SERIES OF WEAK SHORTWAVE TROUGHS OUT OF THE MAIN UPPER TROUGH IN THE
WESTERN CONUS OUT INTO THE CENTRAL PLAINS. MOISTURE RETURN WILL
CONTINUE/REMAIN IN PLACE THROUGH THE PERIOD...SO THE PASSAGE ANY OF
THE SHORTWAVE WILL HAVE THE POTENTIAL TO TRIGGER CONVECTION ACROSS
THE AREA THROUGH THE PERIOD. THIS FAR OUT IT REMAINS VERY DIFFICULT
TO PIN DOWN THE TIMING AND/OR AREAL EXTENT OF ANY CONVECTION AND
MESOSCALE FEATURES SUCH AS OUTFLOW BOUNDARIES FROM POSSIBLE MCS`S
EACH DAY WOULD ONLY COMPLICATE THE FCST. HAVE THEREFORE CONTINUED A
BROAD AND GENERAL FCST ON THE PRECIP POTENTIAL WITH HIGHS GENERALLY
IN THE 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM CDT TUE MAY 21 2013
LATEST OBS SHOW SOME MVFR CIGS TO THE NORTH ACROSS NEB. MODELS
CONTINUE TO SHOW THESE CIGS REMAINING JUST NORTH OF THE TERMINALS
WITH THE 00Z OBJECTIVE MOS GUIDANCE KEEPING CONDITIONS VFR.
THEREFORE WILL MAINTAIN PREV IFR FORECAST. THE RAP AND GFS SUGGEST
SOME DECENT MIXING WITH THE POTENTIAL FOR SOME SFC WIND GUSTS
THROUGH THE LATE MORNING AND AFTERNOON ALONG WITH A STRATOCU DECK
FORMING ABOVE 3 KFT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...53
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
407 AM EDT WED MAY 22 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013
12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOW MOVING UPR LO
OVER ERN SDAKOTA BTWN UPR RDG OVER SCENTRAL CANADA AND A RIDGE OFF
THE SE CONUS. BAND OF SHRA/SCT TS THAT IMPACTED THE CWA EARLIER HAS
LIFTED TO THE N ALONG WITH RESPONSIBLE SHRTWV...ALLOWING FOR MAINLY
DRY WX OVER UPR MI EARLY THIS AFTN. BUT SINCE THE CWA IS N OF SFC
WARM FNT IN WI...PLENTY OF LO CLDS LINGER. THERE IS ALSO SOME FOG...
MAINLY NEAR THE COOLER GREAT LKS. ANOTHER DISTURBANCE IS ROTATING N
THRU IOWA ARND THE CLOSED LO. THE APRCH OF THIS DISTURBANCE HAS
RESULTED IN SOME SHRA OVER CENTRAL WI WHERE BREAKS IN THE LO CLDS
ALONG AND S OF WARM FNT HAVE LIFTED SB CAPE 500-1000 J/KG PER SPC
MESOANALYSIS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS TRENDS ASSOCIATED
WITH SHRTWV IN IOWA AND THEN APRCH OF MAIN UPR LO.
LATE THIS AFTN/TNGT...SHORT RANGE MODELS ARE IN FAIRLY GOOD
AGREEMENT SHOWING SHRA NOW OVER CENTRAL WI DRIFTING ACRS THE WI
BORDER BY 21Z AND THEN CONTINUING TO THE NE. RUC FCST SDNGS MODIFIED
FOR TEMP/DEWPT OF 68/58 YIELDS SBCAPE UP TO 750 J/KG...SO ADDED
MENTION OF TS. RELATIVELY WEAK WINDS SFC-H5 AS WELL AS DEEP
MSTR/SKINNY CAPE WITH PERSISTENT LO CLDS LIMITING DIURNAL HEATING
INDICATE A LO RISK FOR ANY SVR TS...BUT ANY SHRA COULD RESULT IN
SOME HEAVY RA WITH FCST KINX AS HI AS THE UPR 30S. ONCE THE SHRA
MOVE FARTHER TO THE NE AND AWAY FM THE SFC HEATING AREA...ONE MIGHT
EXPECT THESE SHRA TO DIMINISH THRU THE NGT. BUT FCST AREA OF H85-7
FGEN N OF WARM FNT MIGHT ACT TO SUSTAIN THESE SHRA. WL GO WITH HI
CHC-LIKELY POPS THIS EVNG NEAR THE WI BORDER DIMINISHING TO CHCY
POPS TO THE NE. SINCE THE LLVL FLOW IS FCST TO BACK MORE TO THE NE
FOLLOWING THE PASSAGE OF THIS SHRA AREA...EXPECT COOLER LAKE
AIR/SOME FOG TO MOVE BACK INTO THE AREA OVERNGT.
WED...AS CLOSED LO TO THE W BEGINS TO SHIFT FASTER TO THE ESE TO SW
WI BY 00Z THU...AREA OF LARGER SCALE QVECTOR CNVGC WL IMPACT MAINLY
THE AREA NEAR THE WI BORDER BUT WEAKEN WITH TIME AS THE UPR CLO
BEGINS TO OPEN. BAND OF RA ACCOMPANYING AXIS OF SHARPER FGEN OVER
WRN LK SUP/THE WRN ZNS SHOULD THUS SHIFT SLOWLY TO THE SE THRU THE
DAY. ARRIVAL OF DRIER AIR FM THE NW TO THE SE OF EXPANDING HI PRES
OVER SCENTRAL CANADA MIGHT START TO DIMINISH THE PCPN OVER THE FAR W
LATER IN THE DAY. OTRW...LOWERED FCST HI TEMPS TO ACCOUNT FOR STEADY
NE WIND OFF LK SUP AND EXPECTED CLD COVER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM EDT WED MAY 22 2013
A CLOSED 500 MB LOW WILL BE IN THE PACIFIC NW WITH A TROUGH OVER THE
GREAT LAKES REGION AND A RIDGE ACROSS THE PLAINS 12Z THU. PATTERN
CHANGES LITTLE THIS FORECAST PERIOD WITH THE TROUGH OVER THE GREAT
LAKES MOVING TO THE EASTERN U.S. 12Z SAT AND THE RIDGE STAYING PUT
IN THE PLAINS. LOOKS DRY FOR THIS FORECAST PERIOD WITH COLD
TEMPERATURES. THERE WILL BE SOME FROST FOR THU NIGHT AND FRI NIGHT
AND PUT IT IN THE WEATHER GRIDS TO HELP WITH THE FIRE WEATHER
FORECAST. THE FROST/FREEZE SEASON STARTS AFTER MEMORIAL DAY...BUT
WILL MENTION THIS IN THE HWO PRODUCT. WITH THE RIDGE NEARBY AND VERY
DRY AND COLD AIR...GOOD RADIATIONAL COOLING CONDITIONS WILL SET UP
AND WENT WITH THE COLDEST GUIDANCE I COULD FIND FOR LOW TEMPERATURES
WHICH WAS THE ADJMET AND MADE A FEW ADJUSTMENTS FOR COLDER SPOTS.
HIGHS ON THU WILL STRUGGLE TO GET TO THE MID 50S. FOR FRI...WENT
COLDER FOR HIGHS AS WELL WITH A COLDER START IN THE MORNING AND 850
MB TEMPERATURES WARMING ONLY TO 4C. MIXING THIS DOWN TO THE SFC
WOULD GIVE ME HIGHS AROUND 60 AT BEST. THE TEMPERATURES WERE THE
MAIN THING THAT I ADJUSTED FOR THIS FORECAST WITH A SLIGHTLY COLDER
FORECAST.
IN THE EXTENDED...ECMWF AND GFS SHOW A 500 MB RIDGE ACROSS THE
PLAINS WITH TROUGHING IN THE PACIFIC NW AND IN NEW ENGLAND 12Z SAT.
PATTERN CHANGES VERY LITTLE 12Z SUN THROUGH 12Z TUE. WILL BE FAIRLY
DRY THIS FORECAST PERIOD AND QUIET WITH COLDER THAN NORMAL
TEMPERATURES WITH A SLOW WARMING TREND THROUGH THE PERIOD. THERE IS
A SLIGHT CHANCE FOR PCPN MONDAY NIGHT AND TUESDAY WITH A WARM FRONT
SETTING UP TO THE SOUTH...BUT NOT REAL IMPRESSED WITH SEEING MUCH
RAIN OUT OF THIS FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1209 AM EDT WED MAY 22 2013
COOL/MOIST AIR UPSLOPING OFF LAKE SUPERIOR WILL LIKELY RESULT IN
LIFR CONDITIONS AT KIWD/KCMX/KSAW THRU THE NIGHT. CONDITIONS MAY END
UP VLIFR FOR MUCH OF THE NIGHT AT KSAW UNDER A MORE DIRECT LIGHT
UPSLOPE FLOW. EXPECT -SHRA/-DZ AT TIMES...ESPECIALLY AT KIWD/KCMX
DUE TO AN AREA OF MORE PERSISTENT SYNOPTIC FORCING. THESE MORE
PERSISTENT -SHRA SHOULD DRIFT SE AND AFFECT KSAW WED AFTN. THERE IS
LIGHT AT THE END OF THE TUNNEL AS LOW LOW PRES THAT HAS PLAGUED THE
AREA IN RECENT DAYS WILL CONTINUE TO WEAKEN AND WILL BE SHUNTED SE
BY HIGH PRES NOSING S TOWARD THE UPPER LAKES. DRIER AIR ASSOCIATED
WITH THE HIGH WILL LEAD TO STEADILY IMPROVING CONDITIONS FROM N TO S
WED AFTN/EVENING. KIWD/KCMX SHOULD BREAK OUT TO VFR IN THE
EVENING...PERHAPS SOONER...ESPECIALLY AT KCMX. IT MAY NOT BE UNTIL
NEAR THE END OF THIS FCST PERIOD THAT KSAW IMPROVES TO VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 AM EDT WED MAY 22 2013
ARRIVAL OF DRIER AIR FROM THE NW TODAY WILL SLOWLY DIMINISH THE FOG
ON THE GREAT LAKES. GUSTY NORTHERLY WINDS ARE EXPECTED BEHIND THE
LOW PRESSURE SYSTEM TONIGHT INTO THURSDAY...BUT LINGERING WARM AIR
ALOFT SHOULD KEEP WINDS IN 20-25KT RANGE. THEN...A HIGH PRESSURE
RIDGE BUILDING SOUTHEAST OVER THE UPPER GREAT LAKES FOR THURSDAY
NIGHT THROUGH THE WEEKEND WILL BRING LIGHT WINDS TO LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249>251-
266-267.
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>242-245>248-263-265.
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LSZ243-244-
264.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LMZ221-248.
DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ250.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...ROLFSON
MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1210 AM EDT WED MAY 22 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013
12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOW MOVING UPR LO
OVER ERN SDAKOTA BTWN UPR RDG OVER SCENTRAL CANADA AND A RIDGE OFF
THE SE CONUS. BAND OF SHRA/SCT TS THAT IMPACTED THE CWA EARLIER HAS
LIFTED TO THE N ALONG WITH RESPONSIBLE SHRTWV...ALLOWING FOR MAINLY
DRY WX OVER UPR MI EARLY THIS AFTN. BUT SINCE THE CWA IS N OF SFC
WARM FNT IN WI...PLENTY OF LO CLDS LINGER. THERE IS ALSO SOME FOG...
MAINLY NEAR THE COOLER GREAT LKS. ANOTHER DISTURBANCE IS ROTATING N
THRU IOWA ARND THE CLOSED LO. THE APRCH OF THIS DISTURBANCE HAS
RESULTED IN SOME SHRA OVER CENTRAL WI WHERE BREAKS IN THE LO CLDS
ALONG AND S OF WARM FNT HAVE LIFTED SB CAPE 500-1000 J/KG PER SPC
MESOANALYSIS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS TRENDS ASSOCIATED
WITH SHRTWV IN IOWA AND THEN APRCH OF MAIN UPR LO.
LATE THIS AFTN/TNGT...SHORT RANGE MODELS ARE IN FAIRLY GOOD
AGREEMENT SHOWING SHRA NOW OVER CENTRAL WI DRIFTING ACRS THE WI
BORDER BY 21Z AND THEN CONTINUING TO THE NE. RUC FCST SDNGS MODIFIED
FOR TEMP/DEWPT OF 68/58 YIELDS SBCAPE UP TO 750 J/KG...SO ADDED
MENTION OF TS. RELATIVELY WEAK WINDS SFC-H5 AS WELL AS DEEP
MSTR/SKINNY CAPE WITH PERSISTENT LO CLDS LIMITING DIURNAL HEATING
INDICATE A LO RISK FOR ANY SVR TS...BUT ANY SHRA COULD RESULT IN
SOME HEAVY RA WITH FCST KINX AS HI AS THE UPR 30S. ONCE THE SHRA
MOVE FARTHER TO THE NE AND AWAY FM THE SFC HEATING AREA...ONE MIGHT
EXPECT THESE SHRA TO DIMINISH THRU THE NGT. BUT FCST AREA OF H85-7
FGEN N OF WARM FNT MIGHT ACT TO SUSTAIN THESE SHRA. WL GO WITH HI
CHC-LIKELY POPS THIS EVNG NEAR THE WI BORDER DIMINISHING TO CHCY
POPS TO THE NE. SINCE THE LLVL FLOW IS FCST TO BACK MORE TO THE NE
FOLLOWING THE PASSAGE OF THIS SHRA AREA...EXPECT COOLER LAKE
AIR/SOME FOG TO MOVE BACK INTO THE AREA OVERNGT.
WED...AS CLOSED LO TO THE W BEGINS TO SHIFT FASTER TO THE ESE TO SW
WI BY 00Z THU...AREA OF LARGER SCALE QVECTOR CNVGC WL IMPACT MAINLY
THE AREA NEAR THE WI BORDER BUT WEAKEN WITH TIME AS THE UPR CLO
BEGINS TO OPEN. BAND OF RA ACCOMPANYING AXIS OF SHARPER FGEN OVER
WRN LK SUP/THE WRN ZNS SHOULD THUS SHIFT SLOWLY TO THE SE THRU THE
DAY. ARRIVAL OF DRIER AIR FM THE NW TO THE SE OF EXPANDING HI PRES
OVER SCENTRAL CANADA MIGHT START TO DIMINISH THE PCPN OVER THE FAR W
LATER IN THE DAY. OTRW...LOWERED FCST HI TEMPS TO ACCOUNT FOR STEADY
NE WIND OFF LK SUP AND EXPECTED CLD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013
AFTER A WET START TO THE WEEK...THE LONG TERM PERIOD LOOKS TO BE
FAIRLY DRY AS CANADIAN HIGH PRESSURE SLIDES THROUGH THE UPPER GREAT
LAKES REGION.
FIRST...THE UPPER TROUGH THAT HAS BEEN INFLUENCING THE WEATHER FOR
THE START OF THE WORK WEEK WILL BE SITUATED OVER WISCONSIN AND IOWA
AND SHIFTING EAST THROUGH THE GREAT LAKES REGION ON WEDNESDAY
NIGHT. MEANWHILE...THE SURFACE LOW WILL BE LOCATED OVER LOWER
MICHIGAN AT 00Z THURSDAY AND BEGIN TO MOVE UP THE ST LAWRENCE
SEAWAY WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE INTENSIFIES THE
LOW. AS THIS OCCURS...HIGH PRESSURE ORIGINATING FROM NORTH CENTRAL
CANADA WILL BE MOVING A RIDGE INTO THE UPPER MISSISSIPPI VALLEY ON
WEDNESDAY NIGHT AND THE UPPER GREAT LAKES ON THURSDAY. WITH THE
UPPER TROUGH AND CLOSE PROXIMITY OF THE LOW...THERE WILL STILL BE
DEEPER MOISTURE AND 850-700MB Q-VECTOR CONVERGENCE OVER THE
SOUTHEAST HALF OF THE CWA. IN ADDITION...WITH THE INCREASING
NORTHERLY 850-700MB FLOW OVER THE AREA MODELS ARE CONSISTENT ON AN
AREA OF FGEN SETUP FROM IRONWOOD THROUGH EASTERN LAKE SUPERIOR AT
00Z THURSDAY. THEN AS THE LOW SHIFTS EAST...THE FGEN WILL SLIDE
SOUTHEAST THROUGH THE NIGHT AND LIKELY EXIT THE MOST IF NOT ALL OF
THE CWA BY 12Z THURSDAY. AT THIS POINT...THINKING THAT THE MOVEMENT
OF THE PRECIPITATION SHOULD KEEP AMOUNTS UNDER A QUARTER OF AN
INCH.
CANADIAN HIGH PRESSURE THEN BECOMES THE DOMINATING FEATURE FOR THE
REST OF THE PERIOD...AS THE AREA IS UNDER NORTHWEST FLOW ALOFT.
THIS DRY CANADIAN AIR AND COOLER NORTHERLY LOW LEVEL WINDS WILL
LEAD TO NICE BUT SLIGHTLY COOLER THAN NORMAL START TO THE MEMORIAL
DAY WEEKEND. THE STRONGEST NORTHERLY FLOW OFF LAKE SUPERIOR WILL BE
ON THURSDAY WITH THE CLOSER PROXIMITY OF THE EXITING LOW. THIS WILL
KEEP TEMPERATURES COOLER THAN MOST OF THE DAYS...WITH HIGHS IN THE
UPPER 40S NEAR LAKE SUPERIOR AND IN THE 50S INLAND. FRIDAY-SUNDAY
WILL BE DOMINATED BY LAKE BREEZES EACH DAY...WITH THE WARMEST
TEMPERATURES OVER THE INTERIOR LOCATIONS /60S/. THERE ARE HINTS OF A
COUPLE WEAK SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT
FRI-SUN...BUT WILL THE DRY AIR IN PLACE...WOULDN/T EXPECT MUCH FOR
PRECIPITATION CHANCES. UNDER THE HIGH PRESSURE RIDGE ON THURSDAY
NIGHT...EXPECT TO SEE SOME SUB FREEZING LOWS OVER THE INTERIOR
PORTIONS OF UPPER MICHIGAN. PWAT VALUES AROUND 40 PERCENT OF NORMAL
AND LIGHT WINDS WOULD BE FAVORABLE WELL BELOW NORMAL LOWS. MAV/MET
GUIDANCE PICKING UP ON THIS IDEA WITH LOWS BETWEEN 25-30 OVER THE
WEST AND THAT SEEMS FAIRLY REASONABLE. HAVE TRENDED THAT DIRECTION
AND LOWERED TEMPS OVER THE WEST AROUND 5 DEGREES. FROST/FREEZE
HEADLINES DON/T START UNTIL MEMORIAL DAY...SO THERE WON/T BE ANY
HEADLINES...BUT ANYONE THAT HAS PLANTED EARLY WILL NEED TO PREPARE
FOR A POTENTIAL FROST/FREEZE.
UPPER RIDGING THAT WILL BE NEARLY STATIONARY JUST EAST OF THE
NORTHERN ROCKIES DURING THIS PERIOD WILL BEGIN TO SHIFT EAST ON
SUNDAY NIGHT AS THE UPPER TROUGH OVER THE NEW ENGLAND STATES SHIFTS
EAST INTO THE ATLANTIC. THIS WILL START A GRADUAL WARMING TREND
TOWARDS MEMORIAL DAY AND INTO THE FIRST PART OF NEXT WEEK. IN
ADDITION...IT WILL ALSO BRING BETTER OPPORTUNITIES FOR SHORTWAVES
TO RIDE OVER THE RIDGE AND INTO THE AREA LATER MONDAY AND MORE
LIKELY TOWARDS TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1209 AM EDT WED MAY 22 2013
COOL/MOIST AIR UPSLOPING OFF LAKE SUPERIOR WILL LIKELY RESULT IN
LIFR CONDITIONS AT KIWD/KCMX/KSAW THRU THE NIGHT. CONDITIONS MAY END
UP VLIFR FOR MUCH OF THE NIGHT AT KSAW UNDER A MORE DIRECT LIGHT
UPSLOPE FLOW. EXPECT -SHRA/-DZ AT TIMES...ESPECIALLY AT KIWD/KCMX
DUE TO AN AREA OF MORE PERSISTENT SYNOPTIC FORCING. THESE MORE
PERSISTENT -SHRA SHOULD DRIFT SE AND AFFECT KSAW WED AFTN. THERE IS
LIGHT AT THE END OF THE TUNNEL AS LOW LOW PRES THAT HAS PLAGUED THE
AREA IN RECENT DAYS WILL CONTINUE TO WEAKEN AND WILL BE SHUNTED SE
BY HIGH PRES NOSING S TOWARD THE UPPER LAKES. DRIER AIR ASSOCIATED
WITH THE HIGH WILL LEAD TO STEADILY IMPROVING CONDITIONS FROM N TO S
WED AFTN/EVENING. KIWD/KCMX SHOULD BREAK OUT TO VFR IN THE
EVENING...PERHAPS SOONER...ESPECIALLY AT KCMX. IT MAY NOT BE UNTIL
NEAR THE END OF THIS FCST PERIOD THAT KSAW IMPROVES TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT TUE MAY 21 2013
GIVEN WIDESPREAD AREA OF RA THAT IMPACTED MUCH OF LAKE SUP INTO THIS
MORNING...SOME RECENT SHIP OBS THAT INDICATED LO VISIBILITY...AND
SHALLOW COOL AIRMASS OVER THE LAKE...OPTED TO EXTENDED DENSE FOG
ADVY THRU TONIGHT. ARRIVAL OF DRIER AIR FROM THE NW ON WED WILL
SLOWLY DIMINISH THE FOG. OTHERWISE...NE WINDS UP TO 25 TO 30 KTS...
WITH SOME GALE FORCE GUSTS AT THE HIER PLATFORMS...WILL CONTINUE
STRONGEST OVER WESTERN LAKE SUP WHERE TERRAIN FUNNELING WILL ENHANCE
THE WIND SPEEDS.
GUSTY NORTHERLY WINDS ARE EXPECTED BEHIND THE LOW PRESSURE SYSTEM
ON WEDNESDAY NIGHT INTO THURSDAY...BUT LINGERING WARM AIR ALOFT
SHOULD KEEP WINDS IN 20-25KT RANGE. THEN...A HIGH PRESSURE RIDGE
BUILDING SOUTHEAST OVER THE UPPER GREAT LAKES FOR THURSDAY NIGHT
THROUGH THE WEEKEND WILL BRING LIGHT WINDS TO LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 6 AM EDT /5 AM CDT/ EARLY THIS MORNING
FOR LSZ162-243>249-263>267.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ221-248-
250.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
451 AM EDT WED MAY 22 2013
.SYNOPSIS...
MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY.
A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS
AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY
PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A
SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT
LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED
THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T
BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED
WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN
ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH
THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY
THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 418 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE
NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS
DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT
SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT
GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES
DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION
EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE
MESOSCALE COLD POOL HAS BEEN ESTABLISHED.
REMAINING RAIN SHOWERS ACROSS THE NORTH COUNTRY DEPART EWD INTO NH
BY 10Z THIS MORNING. WILL SEE PATCHY FOG AROUND THRU 12Z GIVEN SATURATED
LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW ACROSS
NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS MORNING.
THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU EARLY
AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS ADDITIONAL
RAINFALL IS UNLIKELY THRU ABOUT 19Z. THEREAFTER...THERE IS A SWLY
BACKING AND STRENGTHENING OF 850MB FLOW ACROSS WRN PA INTO CENTRAL
NY PER MODEL GUIDANCE. FEEL THAT REMNANT OUTFLOW BOUNDARY ACROSS
CENTRAL NY WILL ENHANCE ISENTROPIC ASCENT LATE IN THE DAY ACROSS THE
ADIRONDACKS AND S-CENTRAL VT...ALLOWING FOR DEVELOPMENT OF SHOWER
AND TSTM ACTIVITY. THE 00Z NAM SHOWS DEVELOPMENT OF MUCAPE OF
500-1000 J/KG ACROSS ALL BUT NERN PORTION OF THE FORECAST AREA
21-00Z. RAP SOUNDINGS SHOW A BIT MORE INSTABILITY...UP TO 1500
J/KG...THOUGH SFC DEWPOINTS MAY BE A BIT OVERDONE HERE. BASED ON
CONSENSUS OF THE MODELS INCLUDING LOCALLY RUN 4KM WRF...LOOKING
FOR DEVELOPMENT OF A FEW STRONG LATE DAY/EVENING TSTMS AS WELL.
SPC CALIBRATED SVR PROBABILITIES AND DAY 1 OUTLOOK SUPPORT A FEW
SEVERE STORMS...AND MENTIONED GUSTY WINDS AND SMALL HAIL IN THE
FORECAST AND HWO FOR LATE AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR
EXCEEDS 40 KTS AND IS SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z
ALB SOUNDING SHOWED PW VALUES OF 1.52"...AND NWD ADVECTION OF THIS
MOIST AIR MASS WILL ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE
CONVECTION LATE THIS AFTN INTO THIS EVENING. AFTN TEMPS TODAY
HIGHLY DEPEND ON SOME SUNNY BREAKS DURING THE LATE MORNING-MID
AFTN PERIOD. ANTICIPATE SOME INTERVALS OF SUN TODAY...AND WITH
850MB TEMPS OF +14C COULD WARM QUICKLY DURING THE EARLY AFTN. HIGH
TEMPERATURES IN THE VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT
COULD REACH 80F IF WE GET A BIT MORE SUNSHINE AND INSOLATIONAL
HEATING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION
CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY
SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD
SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE
OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE
EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S
DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW
TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S.
THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND
ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD
ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS
WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN
ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF
LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN
PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+"
RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES
INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE
OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY
FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION
BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF
SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES.
FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN
SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME
PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD.
COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE
HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH
DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE
00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE
MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS
CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS
WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND
SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A
CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC
STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF
MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM
AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH
AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE
DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO
500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO
DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE
ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR
SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH
EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES
TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO
DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45
KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35
MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY
IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A
RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS.
SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO
TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF
SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN
THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION
FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING.
CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT
BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN
ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY
07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS
DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING.
MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT
FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD
MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT
MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE
DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC
HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS
SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR
CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY
WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH
AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z
THURSDAY...ESPECIALLY MSS/SLK/MPV.
OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY
INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON
THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR
CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS
WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS
OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME
LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY
SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION
BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE
WEEKEND...WITH AREAS OF LLVL TURBULENCE.
&&
.HYDROLOGY...
430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY
HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST
24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND
TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE
AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND
EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE
BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL
RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR
DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY
OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM
RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE
SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER
THURSDAY AND THURSDAY NIGHT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
425 AM EDT WED MAY 22 2013
.SYNOPSIS...
MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY.
A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS
AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY
PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A
SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT
LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED
THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T
BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED
WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN
ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH
THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY
THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 418 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE
NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS
DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT
SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT
GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES
DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION
EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE
MESOSCALE COLD POOL HAS BEEN ESTABLISHED.
REMAINING RAIN SHOWERS ACROSS THE NORTH COUNTRY DEPART EWD INTO NH
BY 10Z THIS MORNING. WILL SEE PATCHY FOG AROUND THRU 12Z GIVEN SATURATED
LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW ACROSS
NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS MORNING.
THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU EARLY
AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS ADDITIONAL
RAINFALL IS UNLIKELY THRU ABOUT 19Z. THEREAFTER...THERE IS A SWLY
BACKING AND STRENGTHENING OF 850MB FLOW ACROSS WRN PA INTO CENTRAL
NY PER MODEL GUIDANCE. FEEL THAT REMNANT OUTFLOW BOUNDARY ACROSS
CENTRAL NY WILL ENHANCE ISENTROPIC ASCENT LATE IN THE DAY ACROSS THE
ADIRONDACKS AND S-CENTRAL VT...ALLOWING FOR DEVELOPMENT OF SHOWER
AND TSTM ACTIVITY. THE 00Z NAM SHOWS DEVELOPMENT OF MUCAPE OF
500-1000 J/KG ACROSS ALL BUT NERN PORTION OF THE FORECAST AREA
21-00Z. RAP SOUNDINGS SHOW A BIT MORE INSTABILITY...UP TO 1500
J/KG...THOUGH SFC DEWPOINTS MAY BE A BIT OVERDONE HERE. BASED ON
CONSENSUS OF THE MODELS INCLUDING LOCALLY RUN 4KM WRF...LOOKING
FOR DEVELOPMENT OF A FEW STRONG LATE DAY/EVENING TSTMS AS WELL.
SPC CALIBRATED SVR PROBABILITIES AND DAY 1 OUTLOOK SUPPORT A FEW
SEVERE STORMS...AND MENTIONED GUSTY WINDS AND SMALL HAIL IN THE
FORECAST AND HWO FOR LATE AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR
EXCEEDS 40 KTS AND IS SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z
ALB SOUNDING SHOWED PW VALUES OF 1.52"...AND NWD ADVECTION OF THIS
MOIST AIR MASS WILL ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE
CONVECTION LATE THIS AFTN INTO THIS EVENING. AFTN TEMPS TODAY
HIGHLY DEPEND ON SOME SUNNY BREAKS DURING THE LATE MORNING-MID
AFTN PERIOD. ANTICIPATE SOME INTERVALS OF SUN TODAY...AND WITH
850MB TEMPS OF +14C COULD WARM QUICKLY DURING THE EARLY AFTN. HIGH
TEMPERATURES IN THE VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT
COULD REACH 80F IF WE GET A BIT MORE SUNSHINE AND INSOLATIONAL
HEATING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION
CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY
SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD
SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE
OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE
EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S
DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW
TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S.
THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND
ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD
ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS
WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN
ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF
LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN
PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+"
RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES
INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE
OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY
FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION
BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF
SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES.
FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN
SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME
PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD.
COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 225 PM EDT TUESDAY...DEPARTING LOW PRESSURE SYSTEM WILL
HAVE POSITIVELY TILTED UPPER LEVEL TROUGH MOVE OVER THE NORTH
COUNTRY ON FRIDAY...KEEPING CHC OF SHOWERS OVER MUCH OF THE AREA.
LATE FRIDAY IN TO FRIDAY NIGHT...TROUGH LOOKS TO TILT NEUTRAL TO
NEGATIVE AS THE SFC LOW PUSHES OFF THE NEW ENGLAND COAST. SFC LOW
TRAVERSES NEWD NEAR NEWFOUNDLAND...KEEPING BACK/WRN EDGE OF
PRECIP NEAR VT...THEREFORE HAVE KEPT SLGT CHC POPS OVER VT FRIDAY
NIGHT THROUGH FIRST HALF OF SATURDAY. AS HIGH PRESSURE BUILDS
OVER SW HUDSONS BAY...EXTENDING SWD OVER THE CENTRAL GREAT
LAKES...A SHORTWAVE ROTATING ABOUT THE UPPER LEVEL LOW OVER NEW
ENGLAND WILL BE FAIRLY DRY BUT BRING CLOUDS FOR THE REST OF
SATURDAY INTO SATURDAY NIGHT. ON SUNDAY...SOME TROUGHINESS
REMAINING OVER ERN ZONES...WITH CLOUDS OVER MOST OF VT. THE SFC
HIGH PRESSURE AND SOME UPPER LEVEL RIDGING WILL TAKE HOLD OF THE
REGION FOR THE REST OF THE PERIOD.
BELOW NORMAL MAX TEMPS WILL GRADUALLY TREND WARMER THROUGHOUT THE
PERIOD WITH MIN TEMPS GENERALLY IN THE 40S.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION
FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING.
CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT
BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN
ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY
07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS
DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING.
MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT
FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD
MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT
MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE
DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC
HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS
SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR
CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY
WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH
AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z
THURSDAY...ESPECIALLY MSS/SLK/MPV.
OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY
INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON
THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR
CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS
WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS
OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME
LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY
SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION
BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE
WEEKEND...WITH AREAS OF LLVL TURBULENCE.
&&
.HYDROLOGY...
430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY
HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST
24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND
TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE
AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND
EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE
BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL
RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR
DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY
OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM
RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE
SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER
THURSDAY AND THURSDAY NIGHT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...KGM
AVIATION...TABER
HYDROLOGY...BANACOS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
136 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN
CAROLINAS. SHOWERS AND THUNDERSTORMS WILL INCREASE ON THURSDAY AHEAD
OF A COLD FRONT THAT WILL CROSS THE REGION EARLY FRIDAY. COOLER AND
DRIER WEATHER WILL FOLLOW FOR THE WEEKEND AND EARLY NEXT WEEK AS
HIGH PRESSURE MOVES OFF THE EAST COAST.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 130 AM THURSDAY...ONLY CHANGES TO THE FORECAST WERE TO
INCREASE CLOUD COVER INLAND GIVEN THE RECENT DEVELOPMENT OF PLENTY
OF LOW STRATUS FROM THE PEE DEE REGION AS FAR EAST AS WHITEVILLE AND
ELIZABETHTOWN. THE LAST FOUR RUNS OF THE HRRR ARE INSISTENT THAT
SCATTERED SHOWERS WILL DEVELOP JUST WEST OF I-95 IN THE NEXT FEW
HOURS. THIS LINES UP NICELY WITH WHAT`S LEFT OF THE 700-500 MB SHEAR
AXIS THAT HAS DEVELOPED CONVECTION EACH OF THE LAST TWO NIGHTS. I
HAVE ONLY INCLUDED A TINY 15-20 PERCENT POP MAINLY FOR THE
DARLINGTON-BENNETTSVILLE CORRIDOR. OTHERWISE NO SIGNIFICANT
CHANGES. PREVIOUS DISCUSSION FROM 1000 PM FOLLOWS...
THE DIURNALLY DRIVEN CONVECTION HAS ENDED ACROSS THE AREA WITH THE
LOSS OF HEATING. SOME OF THE HIGHEST RESOLUTION MODELS ARE
INDICATING A FEW SHOWERS MAY DEVELOP AFTER MIDNIGHT. WE DO EXPECT
CONVECTION TO DEVELOP/EXPAND ACROSS THE WATERS AS A WEAK UPPER LEVEL
DISTURBANCE PASSES UP THE COAST...TO OUR E. IT IS POSSIBLE THAT THE
CONVECTION MAY DEVELOP/EXPAND ONTO THE IMMEDIATE COAST VERY LATE
TONIGHT...BUT THE RISK REMAINS SMALL. CONSIDERABLE EVE CLOUD COVER
WILL CONTINUE TO VERY SLOWLY DIMINISH DURING THE LATE NIGHT.
NIGHTTIME TEMPS WILL AGAIN BE ABOVE NORMAL...MID AND UPPER 60S. THE
LAST TIME MINIMUMS WERE BELOW NORMAL WAS ON MAY 15TH.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...DEEP SOUTH TO SOUTHWEST FLOW FOR MUCH OF THE
PERIOD WILL CONTINUE TO PUMP PLENTY OF GULF MOISTURE INTO THE
REGION. BERMUDA HIGH AND MID LEVEL RIDING OVER THE WESTERN ATLANTIC
BRIEFLY EXPAND WEST WED. INCREASE IN MID LEVEL SUBSIDENCE WILL
LIMIT COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS. DIURNAL
INSTABILITY ALONG WITH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
AND CONVERGENCE ALONG THE SEA BREEZE HOWEVER SUGGEST POP WILL NOT
BE ZERO. GIVEN THE LIMITING FACTORS SLIGHT CHANCE TO LOW CHANCE
SEEMS REASONABLE WITH INLAND SC FAVORED. WORTH NOTING THAT THE 12Z
NAM IS NOT AS AGGRESSIVE WITH THE BUILDING RIDGE AND IS SLOWER TO
EXIT THE SHORTWAVE REMNANTS. DISCOUNTING THIS SCENARIO FOR NOW AS
IT IS A SIGNIFICANT CHANGE FROM PREVIOUS SOLUTIONS BUT SHOULD IT
VERIFY POP WOULD NEED TO BE MUCH HIGHER.
MID LEVEL RIDGE QUICKLY WEAKENS THU WITH 5H TROUGH APPROACHING FROM
THE WEST. WHILE THE LOCAL ENVIRONMENT REMAINS RELATIVELY
UNCHANGED...DEEP SOUTHERLY FLOW PUSHES PWATS NEAR 1.8 INCHES...THE
LOSS OF SUBSIDENCE WILL RESULT IN A SIGNIFICANT INCREASE IN STORM
COVERAGE. IN ADDITION ANOTHER STRETCHED SHORTWAVE WILL MOVE INTO THE
AREA FROM THE BAHAMAS EARLY THU. PVA AHEAD OF IT REACHES THE AREA
LATE WED NIGHT OR THU MORNING AND SHOULD ENHANCE CONVECTION. AS HAS
BEEN THE CASE OVER THE PAST FEW DAYS THE ENVIRONMENT IS NOT
SUPPORTIVE OF SEVERE WEATHER. HOWEVER DEEP WARM LAYER AND RELATIVELY
SLOW STORM MOTION WITH POTENTIAL FOR TRAINING STORMS WILL KEEP THE
FLOOD THREAT ELEVATED...ESPECIALLY IN AREAS THAT HAVE ALREADY
RECEIVED SIGNIFICANT RAINFALL THE LAST FEW DAYS.
CONVECTION WILL BE WINDING DOWN THU EVENING AS DRY AIR JUST AHEAD OF
THE 5H TROUGH AXIS AND SURFACE COLD FRONT STARTS TO MOVE IN. COLD
FRONT IS SLOW TO CROSS THE AREA...NOT REACHING THE COAST UNTIL CLOSE
TO THE END OF THE PERIOD...BUT ALOFT WESTERLY FLOW STARTS DEVELOPING
BEFORE 00Z FRI. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE CLIMO...WITH
NUMBERS TEMPERED BY CLOUDS IN SOME AREAS WHILE LOWS CONTINUE TO RUN
ABOVE CLIMO.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...CHANGE IN AIR MASS EXPECTED ON FRIDAY AS
COLD FRONT MAKES ITS WAY OFF SHORE AND COOL CANADIAN HIGH PRESSURE
BUILDS IN. EXPECT COOLER AND DRIER AIR TO MAKE ITS WAY INTO THE
COASTAL CAROLINAS IN DEEP WEST TO NORTHWEST FLOW. PCP WATER VALUES
UP ABOVE 1.5 INCHES OVER THE DAYS LEADING UP TO FRIDAY WILL DROP
OUT TO LESS THAN AN INCH BY FRI AFTN AND BE DOWN TO LESS THAN A
HALF INCH BY SAT MORNING AS ATMOSPHERIC COLUMN DRIES OUT.
THEREFORE DO NOT EXPECT ANY PCP THROUGH THE WEEKEND IN A
RELATIVELY COOLER AND DRIER NORTHERLY FLOW.
AS FOR TEMPS...FRIDAY SHOULD MAKE IT INTO THE 80S IN MOST PLACES BUT
WILL FEEL COOLER AND DRIER BY THE END OF THE DAY. THE 850 TEMPS DROP
FROM CLOSE TO 15C PREVIOUS DAYS DOWN TO 8 TO 10C THROUGH THE
WEEKEND. SATURDAY AND SUNDAY TEMPS WILL REMAIN BETWEEN 75 TO 80 MOST
PLACES WITH MUCH LOWER DEWPOINTS REACHING DOWN INTO THE 40S INLAND
TO AROUND 50 ALONG THE COAST AS COMPARED TO 65 THE PREVIOUS DAYS.
WILL ALSO SEE MUCH GREATER DIURNAL SWINGS DUE TO THE DRY AIR MASS IN
PLACE. OVERNIGHT LOWS WILL REACH DOWN TO THE LOWER END OF THE 50S
BOTH FRI NIGHT AND SAT NIGHT IN COOL ADVECTION AND BETTER
RADIATIONAL COOLING SAT NIGHT AS HIGH PRESSURE SHIFTS OVERHEAD.
BY LATE SUNDAY INTO MONDAY THE HIGH PRESSURE WILL SHIFT OFF SHORE
GIVING WAY TO A WARMER MOISTER RETURN FLOW THROUGH EARLY NEXT WEEK.
THEREFORE WILL SEE A WARMING TREND. THE GFS SHOWS A WEAK COLD FRONT
DROPPING SOUTH INTO NORTH CAROLINA LATE MONDAY INTO TUES. THEREFORE
WILL SHOW CLOUDS AND CHC OF PCP BACK IN THE FORECAST HOLDING TO THE
NORTH ON MONDAY AND OVER LOCAL AREA BY TUES.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...THROUGH DAYBREAK...RICH LOW LEVEL MOISTURE WILL HELP
DEVELOP PATCHES OF LOW STRATUS INLAND...PERIODICALLY AFFECTING THE
FLO/LBT AIRPORTS THROUGH 09Z. THE EXPECTATION IS STRATOCUMULUS
CLOUDS DEVELOPING JUST ABOVE THE STRATUS AROUND 2000-3000 FT AGL
WILL HELP ERODE THE LOWER IFR DECK BY 09Z. AT THE COAST VFR
CONDITIONS COULD COME DOWN INTO THE MVFR RANGE AS THE SAME MOISTURE
AROUND 2000-3000 FT AGL PRODUCES A SCT-BKN LAYER OF STRATOCUMULUS IN
THE NEXT FEW HOURS. LIGHT SOUTH WINDS.
AFTER DAYBREAK....ANTICIPATE VFR CONDITIONS WILL PREVAIL WITH
SCATTERED TO OCNL BKN CU/TCU DEVELOPING BY LATE MORNING. SFC WINDS
FROM THE SOUTH WILL INCREASE TO 10-15 KT WITH HIGHER GUSTS AT
CRE/MYR/ILM WITH THE AFTERNOON SEABREEZE. ISOLATED SHRA/TSRA ARE
POSSIBLE INLAND...BUT PROBS ARE TOO LOW TO INCLUDE IN THE TAF AT
THIS TIME.
EVENING HOURS...VFR WITH DIMINISHING WINDS.
EXTENDED OUTLOOK...SLIGHT CHC OF SHOWERS WEDNESDAY. SHOWERS/T-STORMS
POSSIBLE THURSDAY THROUGH EARLY FRIDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 1000 PM FOLLOWS...
A BERMUDA RIDGE WILL CONTINUE TO DOMINATE THE WATERS AS A WEAK UPPER
LEVEL DISTURBANCE MOVES UP THE COAST...TO OUR E. S TO SW WINDS WILL
BE AROUND 10 KT OR LESS FOR THE REMAINDER OF THE NIGHT. SEAS WILL BE
NEAR 3 FT. A WEAK 7 TO 8 SECOND SE SWELL WILL REMAIN.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...BERMUDA HIGH REMAINS IN CONTROL WED BEFORE
RETREATING EAST THU AHEAD OF A COLD FRONT EXPECTED TO CROSS THE
WATERS LATE THU NIGHT. WED BERMUDA HIGH MAINTAINS SOUTHERLY FLOW
WITH SPEEDS OF 10 TO 15 KT RANGE AND SEAS 2 TO 4 FT. WIND SPEEDS
INCREASE SLIGHTLY THEN VEER THU INTO THU NIGHT AS THE COLD FRONT
APPROACHES FROM THE WEST. WINDS WILL GENERALLY BE 10 TO 15 KT WITH
PERIODS OF SUSTAINED 15 KT LIKELY...ESPECIALLY IN THE AFTERNOON.
WINDS EVENTUALLY VEER TO WEST LATE THU NIGHT AS FRONT PASSES. SEAS
BRIEFLY RISE TO 3 TO 5 FT THU THEN DROP BACK TO 2 TO 4 FT AS PERIOD
ENDS.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...COLD FRONT MOVING FARTHER ON FRIDAY AS
COOLER AND DRIER CANADIAN HIGH PRESSURE BUILDS IN BEHIND IT
THROUGH THE WEEKEND. WINDS WILL VEER AROUND FROM WEST AROUND 10
KTS FRIDAY MORNING...TO NORTH TO NORTHEAST AT 15 TO 20 KTS FRIDAY
NIGHT INTO SATURDAY IN COOL SURGE AND TIGHTENED GRADIENT. WINDS
WILL LIGHTEN AND CONTINUE TO VEER AS HIGH PRESSURE SHIFTS OVERHEAD
ON SUNDAY.
SEAS WILL BE ENTIRELY WIND-WAVE DOMINATED BETWEEN 3 AND 5 FT THROUGH
FRI INTO SATURDAY. BY LATE SATURDAY INTO SUNDAY...THE SEAS WILL
SUBSIDE AND WINDS LIGHTEN AS HIGH SHIFTS CLOSER OVERHEAD. EXPECT
SEAS DOWN TO 3 FT OR LESS BY SAT NIGHT INTO SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RJD/TRA
SHORT TERM...III
LONG TERM...RGZ
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
112 AM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 112 AM CDT WED MAY 22 2013
ONLY MINIMAL CHANGES WERE NEEDED FOR THIS EARLY MORNING FORECAST
UPDATE. CLOUDS CONTINUE TO CLEAR ACROSS THE NORTH WITH HIGH
PRESSURE SLOWLY BUILDING SOUTH INTO THE NORTHERN PLAINS. ISOLATED
TO SCATTERED LIGHT RAIN WILL PERSIST CENTRAL AND SOUTH...WITH
CHANCES FOR PRECIPITATION DIMINISHING FROM NORTH TO SOUTH NOW
THROUGH 15Z...AS THE UPPER LOW CONTINUES TO MOVE SOUTH AND EAST
TOWARDS THE MISSISSIPPI VALLEY. WILL MAINTAIN FOG IN THE FORECAST
NORTH WITH T/TD SPREADS NEARING ZERO AT SOME LOCATIONS WHERE SKIES
HAVE CLEARED.
UPDATE ISSUED AT 853 PM CDT TUE MAY 21 2013
ISENTROPIC LIFT PERSISTS ACROSS THE SOUTH AND WEST...WITH THE WEST
LIKELY GETTING SOME UPSLOPE COMPONENT AS WELL AS EASTERLY LOW
LEVEL WINDS CONTINUE TO PULL LOW LEVEL MOISTURE INTO THE REGION.
UPPED THE CHANCE OF RAIN SHOWERS TO LIKELY ACROSS PORTIONS OF THE
SOUTH FOR THE EVENING AND EARLY MORNING. SO FAR DO NOT SEE A FIRM
TREND ON CLEARING ACROSS THE NORTH YET. SO HAVE SLOWED THE
PROGRESSION OF CLEARING UNTIL LATER TONIGHT. THIS MAY CAUSE SOME
PROBLEMS WITH FOG FORMATION NORTH UNTIL LATE. UPSLOPE FLOW
CONTRIBUTING TO LIGHT FOG SOUTHWEST THIS EVENING.
UPDATE ISSUED AT 650 PM CDT TUE MAY 21 2013
AT 6 PM CDT...THE CLOUD SHIELD EXTENDS ACROSS ALL OF NORTH DAKOTA
EXCEPT THE FAR NORTHERN TIER OF COUNTIES WHERE BREAKS IN THE
OVERCAST ARE NOW FORMING. AFTER SUNSET THE EAST NORTHEAST FLOW OUT
OF CANADA WITH WARMER TEMPERATURES AND LOWER DEW POINTS WILL
FURTHER ERODE THE CLOUDS. WITH MINOT STILL REPORTED A LIGHT SHOWER
ADDED SPRINKLES FOR SEVERAL HOURS THIS EVENING ALONG AND NORTH OF
LAKE SAKAKAWEA EXCLUDING THE NORTHERN BORDER COUNTIES WHERE
CLEARING WILL DEFINITELY BE FOUND. ACROSS THE SOUTH HALF WILL
STILL SEE SCATTERED SHOWERS THIS EVENING FOLLOWED BY CLEARING
OVERNIGHT. WILL THE NORTH CLEARING BY MIDNIGHT...AND ABUNDANT
SURFACE MOISTURE PRESENT...AREAS OF FOG STILL LOOK REASONABLE.
TEMPERATURE TRENDS LOOK GOOD AND DID NOT TOUCH THEM WITH THIS
FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE END OF THE LONG DURATION
RAINFALL EVENT ACROSS THE AREA.
FOR TONIGHT...THE RAP THROUGHOUT THE DAY HAS HAD A GOOD HANDLE ON
THE STRATUS DECK ACROSS THE AREA..AND FOLLOWED ITS LATEST 19 UTC
RUN FOR CLOUD COVER THROUGH THE NIGHT WHICH ADVECTS DRIER AIR
SOUTHWEST AND SCOURS OUT THE STRATUS. DID ADD A MENTION OF FOG TO
THE NORTHWEST AND NORTH CENTRAL WHERE SKIES FIRST CLEAR TONIGHT
AND WINDS BECOME LIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING
INTO THE UPPER 30S AND SATURATION IN LIGHT OF THE RECENT RAINFALL.
A QUIET WEDNESDAY IS FORECAST WITH A SURFACE RIDGE AXIS ACROSS THE
AREA. GIVEN GOOD MODEL AGREEMENT...USED A BLEND OF THE 12 UTC
GEM/GFS/NAM/ECMWF AND 15 UTC SREF FOR ALL FIELDS...WITH GENERALLY
SUNNY SKIES AND HIGHS IN THE 60S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013
BY WEDNESDAY NIGHT AN UPPER LEVEL SHORTWAVE RIDGE BETWEEN THE
EXITING LOW PRESSURE SYSTEM TO THE EAST...AND THE ESTABLISHED UPPER
LEVEL LOW OVER THE WEST COAST/ROCKIES...WILL BE SITUATED OVER THE
PLAINS OF NORTH AMERICA. AT THE SURFACE...COOL HIGH PRESSURE RIDGE
MOVING SOUTH FROM CANADA NOSES INTO THE DAKOTAS.
BY THURSDAY THE SURFACE PRESSURE GRADIENT INCREASES AS THE
INTENSIFYING SURFACE LOW OVER THE ROCKIES/LEE OF THE ROCKIES SETS UP
A STRONGER SOUTHERLY/SOUTHEASTERLY WIND FLOW ACROSS THE WESTERN
PLAINS. SOUTHEAST WINDS 20 TO 30 MPH CAN BE EXPECTED OVER THE
WESTERN THIRD OF NORTH DAKOTA.
FRIDAY THROUGH THE MEMORIAL DAY WEEKEND...THE LARGE UPPER LEVEL LOW
OVER THE ROCKIES SETS UP A SOUTHWEST FLOW ALOFT OVER NORTH
DAKOTA...AND A SERIES OF UPPER LEVEL IMPULSES WILL TRAVERSE
NORTHEASTWARD ACROSS THE DAKOTAS. THUS A CHANCE OF THUNDERSTORMS
THROUGHOUT THIS PERIOD.
FAIRLY SEASONABLE TEMPERATURES IN THE LONG TERM...WITH HIGHS IN THE
60S AND 70S AND LOWS IN THE 40S AND 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 112 AM CDT WED MAY 22 2013
BOUNDARY LAYER MOISTURE CONTINUES TO DECREASE...WITH MAINLY VFR
CIGS NOW AT KDIK-KBIS-KJMS...CLEAR SKIES AT KMOT...AND TRENDING
TOWARDS SKC AT KISN. MAY STILL SEE SOME MVFR CIGS AT THE SOUTHERN
TERMINALS OF KDIK-KBIS-KJMS EARLY THIS MORNING. ALL TERMINALS WILL
BE SKC BY 15-18Z TODAY AND REMAIN SO THROUGH THE REMAINDER OF THE
06Z TAF PERIOD.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT TUE MAY 21 2013
FLOOD WARNINGS CONTINUE FOR THE PIPESTEM CREEK NEAR PINGREE AND
THE FORECAST POINTS OF TOWNER...BANTRY AND WESTHOPE ON THE SOURIS.
CONTINUING TO MONITOR THE WINTERING RIVER NEAR KARLSRUHE AND THE
WILLOW CREEK NEAR WILLOW CITY WHICH MAY APPROACH FLOOD STAGE IN
THE NEXT 24-48 HOURS. HAVE HELD OFF ON A FLOOD WARNING FOR
NOW...AND WILL WATCH HOW THESE WATERWAYS RESPOND TO RUNOFF.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
430 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A
COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY
TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER
AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS
INTO THE OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SOMEWHAT-DISORGANIZED SURFACE LOW IS CURRENTLY LOCATED IN IOWA
AND NORTHERN ILLINOIS. THIS LOW WILL SLOWLY MOVE TO THE EAST
TODAY...STRENGTHENING SLIGHTLY AS IT CROSSES THE SOUTHERN GREAT
LAKES. SOUTH OF THE LOW...A WEAK COLD FRONT WILL MOVE INTO THE ILN
CWA BY EVENING. THIS FRONT IS TOUGH TO PICK OUT ON SURFACE
TEMPERATURE FIELDS...BUT IS A BIT MORE EVIDENT WHEN EXAMINING
THETA-E SLIGHTLY ALOFT...AND ALSO LOOKING FOR SLIGHT WIND SHIFT
FROM SSW TO WSW. AT THE SAME TIME...A CLOSED UPPER LOW OVER THE
NORTHERN MISSISSIPPI VALLEY WILL BEGIN ITS MOVE TO THE EAST...WITH
A SHORTWAVE ROTATING NORTHEAST THROUGH INDIANA AND MICHIGAN. IN
THE RIGHT ENTRANCE REGION OF AN UPPER JET...THE SETUP OVER OHIO
WILL BE FAVORABLE FOR LARGE-SCALE LIFT.
THE STANDARD SUITE OF MODELS (GFS/NAM/CMC/ECMWF) HAS THUS FAR
APPEARED MUCH TOO AGGRESSIVE WITH THE OVERNIGHT PRECIPITATION
FORECAST OVER ILLINOIS AND INDIANA. THIS IS ADMITTEDLY A REGION
WHERE LIFT IS FORECAST TO CONTINUE TO ENHANCE THROUGH MORNING...IN
A REGION OF FALLING HEIGHTS AND A 30-40 KNOT LLJ. DEWPOINTS NORTH
OF THE CURRENT TENNESSEE CONVECTION ARE ABOUT 3-6 DEGREES LOWER THAN
IN THE SOUTHERN STATES...BUT THE AIR MASS COULD NOT BE DESCRIBED
AS PARTICULARLY DRY. AS WAS THE CASE YESTERDAY...THE HRRR HAS THE
CLOSEST APPROXIMATION TO THE CURRENT ACTIVITY. SEVERAL OTHER
CONVECTIVE-ALLOWING MODELS DEPICT QUITE A BIT OF CONVECTION MOVING
INTO THE ILN CWA AS EARLY AS 12Z...WHICH DOES NOT APPEAR REALISTIC
GIVEN THE LACK OF INSTABILITY AND CURRENT RADAR TRENDS. THE
OVERALL CHANCES FOR RAIN IN THE ILN CWA DO NOT APPEAR PARTICULARLY
HIGH THROUGH THE MORNING HOURS...THOUGH SLIGHTLY MORE SO IN THE
WESTERN PART OF THE CWA.
THE MAIN CONCERN FOR THE FORECAST TODAY IS THE POTENTIAL FOR
SEVERE WEATHER THIS AFTERNOON. GIVEN THE WIDE VARIANCE IN THE
HANDLING OF THE CURRENT WEATHER SITUATION...AND THE FACT THAT
THESE MESOSCALE FEATURES WILL BE VERY IMPORTANT IN CONVECTIVE
FORECASTING FOR THIS AFTERNOON...IT IS TOUGH TO TRUST ANY OF THE
SPECIFIC QPF/SIM-RADAR DEPICTIONS FOR THE AFTERNOON HOURS.
TO BEGIN WITH THE BIGGEST LIMITING FACTOR FOR TODAY...INSTABILITY
WILL BE IN QUESTION. GIVEN THE EXPECTED CLOUD COVER...AND EVEN
PRECIPITATION IN SOME PLACES...THE SURFACE TEMP FORECAST IS ON THE
LOW SIDE OF GUIDANCE. GIVEN THE THERMAL PROFILE...MLCAPE WILL
STRUGGLE TO REACH 1000 J/KG...WITH THE MOST INSTABILITY FORECAST
TO BE IN THE SOUTHEASTERN PARTS OF THE CWA. IN THE
NORTHWEST...WHERE TEMPS WILL BE THE COOLEST...INSTABILITY WILL BE
EVEN LESS (500 J/KG OR SO). SOUNDINGS ARE RELATIVELY MOIST THROUGH
THEIR DEPTH...WITH RATHER LOW LCL HEIGHTS (AROUND 2000-3000 FEET
AGL) FORECAST ON THE GFS/NAM (THE RAP13 APPEARS A BIT DRIER).
BECAUSE OF THE MOIST CONDITIONS...THE CAPE PROFILE IS NARROW.
UNLIKE YESTERDAY...THE OVERALL FORCING ENVIRONMENT WILL BE MORE
FAVORABLE FOR CONVECTIVE DEVELOPMENT...EVEN IF INSTABILITY IS
WEAK. WIND SHEAR IS ALSO SOMEWHAT OF A STRENGTH FOR
TODAY...ALTHOUGH MODEL-TO-MODEL ASSESSMENT ON SHEAR VALUES IS NOT
IN AS GOOD OF CONSENSUS AS IS USUALLY THE CASE. MOST OF THE SHEAR
WILL BE FAIRLY UNIDIRECTIONAL (ALL IN THE TOP-RIGHT QUADRANT OF
THE HODOGRAPH)...BUT WITH A DECENT CHANGE IN SPEED. 30-40 KNOTS OF
DEEP LAYER SHEAR WILL BE PRESENT...WITH 15-25 KNOTS IN THE 0-1KM
LAYER. 0-3KM SRH VALUES WILL GET INTO THE 100-200 RANGE...SO THERE
WILL CERTAINLY BE SOME POTENTIAL FOR ROTATING STORMS. THIS COULD
BE ENHANCED BY BOUNDARY INTERACTIONS OR AREAS OF BACKING SURFACE
WINDS (PERHAPS FURTHER NORTH AND CLOSER TO THE SURFACE LOW).
THE LACK OF INSTABILITY...ESPECIALLY IN THE HAIL GROWTH
ZONE...WILL LIMIT THE POTENTIAL FOR LARGE HAIL (PERHAPS OUTSIDE OF
A STRONGER / ROTATING UPDRAFT). THE THREAT FOR STRONG WINDS AND
TORNADOES DOES APPEAR TO EXIST...BUT THE THERMODYNAMIC ENVIRONMENT
SEEMS TO LIMIT THIS FROM BEING A HIGHER-END SEVERE EVENT. A
CLOUDIER/GRUNGIER MORNING WOULD SUPPORT AN ISOLATED SEVERE THREAT
WITH CLUSTERS OF STORMS CAPABLE OF STRONG WINDS AND MAYBE A BIT OF
ROTATION. THE OUTSIDE SHOT FOR TODAY WOULD BE A GREATER DEAL OF
BOUNDARY LAYER DESTABILIZATION (BETWEEN INSOLATION AND MOISTURE
ADVECTION)...WHICH WOULD BRING A GREATER RISK OF ALL THE SEVERE
MODES COMING TO THE TABLE. HOWEVER...GIVEN ALL THE EVIDENCE...THIS
FORECAST WILL LEAN TOWARD THE FORMER SOLUTION. THE HWO WILL FOLLOW
SUIT WITH A RELATIVELY TYPICAL-SOUNDING SEVERE THREAT WORDING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE INITIAL COLD FRONT WILL BE CROSSING THE ILN CWA DURING THE
EVENING HOURS...PRODUCING A RELATIVELY SMALL CHANGE IN THE
TEMPERATURE AND WIND FIELDS. BEHIND THE FRONT...PRECIPITATION WILL
BECOME LESS LIKELY...ESPECIALLY IN THE SOUTH AND SOUTHWEST
PORTIONS OF THE CWA.
A SECONDARY TROUGH (BOTH ALOFT AND AT THE SURFACE) WILL BE
ROTATING SOUTHEAST THROUGH THE CWA ON THURSDAY. THIS WILL BRING A
RENEWED CHANCE OF PRECIPITATION...ESPECIALLY IN THE NORTHERN AND
EASTERN PARTS OF THE CWA. INSTABILITY WILL BE VERY WEAK...BUT JUST
ENOUGH FOR SOME RISK OF THUNDER. THE AIR MASS ALOFT WILL BE
INCREASINGLY COLD...HELPING TO LEAD TO THE POSSIBILITY OF
CONVECTIVE SHOWERS.
ALONG WITH THIS ACTIVITY WILL BE A SECONDARY COLD FRONT...MUCH
BETTER DEFINED THAN THE FIRST. A NNW WIND SHIFT WILL ALLOW FOR
COLD ADVECTION TO BEGIN ON THURSDAY (AND ESPECIALLY THURSDAY
NIGHT). AS A RESULT...THE MAX TEMP GRADIENT FOR THURSDAY IS
SOMEWHAT SHARP (ABOUT 10 DEGREES FROM SW TO NE) AND THURSDAY
NIGHT MIN TEMPS MAY GET INTO THE 30S IN THE NORTHERN PORTIONS OF
THE CWA.
WITH DRY HIGH PRESSURE IN PLACE FOR FRIDAY...RELATIVELY TRANQUIL
CONDITIONS ARE EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
DRY WEATHER SHOULD CONTINUE ON SATURDAY FOR MOST OF THE AREA
EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A DEVELOPING FRONTAL
BOUNDARY MAY CAUSE A FEW SHOWERS.
FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO
LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF
SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH
NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER.
SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY
WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND
SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY
ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE
SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS
SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES
SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA
TONIGHT.
LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS IN AN
INSTABILITY MINIMUM EARLY THIS MORNING. AS SUCH...THE LOW LEVEL
JET THAT IS FORECAST TO DEVELOP OVERNIGHT SHOULD PRODUCE SOME
SCATTERED SHOWERS AND PERHAPS A RUMBLE OF THUNDER.
FOR TODAY INTO THIS EVENING...THE PROSPECTS OF SHOWERS AND
THUNDERSTORMS WILL INCREASE THROUGH THE DAY AS DAYTIME HEATING
INTERACTS WITH LARGE SCALE SYNOPTIC LIFT. BEST CHANCE FOR
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE FROM MID AFTERNOON
INTO THE EVENING HOURS. HAVE PLACED THIS IN THE TAFS WITH A
PREDOMINANT MVFR -SHRA AND A VCTS/CB. AS STORMS BECOME MORE APPARENT
AND CAN BE TRACKED ON RADAR...TAFS WILL BE FINED TUNED
ACCORDINGLY. WITH A MOIST AIRMASS...SOME LOCAL MVFR CIGS AND IFR
VSBYS WILL BE POSSIBLE IN THUNDERSTORMS. DAYTIME HEATING/MIXING
WILL PRODUCE SOUTH/SOUTHWEST WINDS OF 10-15 KNOTS WITH GUSTS
AROUND 25 KNOTS.
FOR TONIGHT...A COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE
REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY.
HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS
AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT.
HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE
BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A
REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL LIKELY RESULT IN SOME
MVFR CIGS.
OUTLOOK...MVFR CONDITIONS POSSIBLE THURSDAY INTO THURSDAY EVENING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
412 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A
COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY
TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER
AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS
INTO THE OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SOMEWHAT-DISORGANIZED SURFACE LOW IS CURRENTLY LOCATED IN IOWA
AND NORTHERN ILLINOIS. THIS LOW WILL SLOWLY MOVE TO THE EAST
TODAY...STRENGTHENING SLIGHTLY AS IT CROSSES THE SOUTHERN GREAT
LAKES. SOUTH OF THE LOW...A WEAK COLD FRONT WILL MOVE INTO THE ILN
CWA BY EVENING. THIS FRONT IS TOUGH TO PICK OUT ON SURFACE
TEMPERATURE FIELDS...BUT IS A BIT MORE EVIDENT WHEN EXAMINING
THETA-E SLIGHTLY ALOFT...AND ALSO LOOKING FOR SLIGHT WIND SHIFT
FROM SSW TO WSW. AT THE SAME TIME...A CLOSED UPPER LOW OVER THE
NORTHERN MISSISSIPPI VALLEY WILL BEGIN ITS MOVE TO THE EAST...WITH
A SHORTWAVE ROTATING NORTHEAST THROUGH INDIANA AND MICHIGAN. IN
THE RIGHT ENTRANCE REGION OF AN UPPER JET...THE SETUP OVER OHIO
WILL BE FAVORABLE FOR LARGE-SCALE LIFT.
THE STANDARD SUITE OF MODELS (GFS/NAM/CMC/ECMWF) HAS THUS FAR
APPEARED MUCH TOO AGGRESSIVE WITH THE OVERNIGHT PRECIPITATION
FORECAST OVER ILLINOIS AND INDIANA. THIS IS ADMITTEDLY A REGION
WHERE LIFT IS FORECAST TO CONTINUE TO ENHANCE THROUGH MORNING...IN
A REGION OF FALLING HEIGHTS AND A 30-40 KNOT LLJ. DEWPOINTS NORTH
OF THE CURRENT TENNESSEE CONVECTION ARE ABOUT 3-6 DEGREES LOWER THAN
IN THE SOUTHERN STATES...BUT THE AIR MASS COULD NOT BE DESCRIBED
AS PARTICULARLY DRY. AS WAS THE CASE YESTERDAY...THE HRRR HAS THE
CLOSEST APPROXIMATION TO THE CURRENT ACTIVITY. SEVERAL OTHER
CONVECTIVE-ALLOWING MODELS DEPICT QUITE A BIT OF CONVECTION MOVING
INTO THE ILN CWA AS EARLY AS 12Z...WHICH DOES NOT APPEAR REALISTIC
GIVEN THE LACK OF INSTABILITY AND CURRENT RADAR TRENDS. THE
OVERALL CHANCES FOR RAIN IN THE ILN CWA DO NOT APPEAR PARTICULARLY
HIGH THROUGH THE MORNING HOURS...THOUGH SLIGHTLY MORE SO IN THE
WESTERN PART OF THE CWA.
THE MAIN CONCERN FOR THE FORECAST TODAY IS THE POTENTIAL FOR
SEVERE WEATHER THIS AFTERNOON. GIVEN THE WIDE VARIANCE IN THE
HANDLING OF THE CURRENT WEATHER SITUATION...AND THE FACT THAT
THESE MESOSCALE FEATURES WILL BE VERY IMPORTANT IN CONVECTIVE
FORECASTING FOR THIS AFTERNOON...IT IS TOUGH TO TRUST ANY OF THE
SPECIFIC QPF/SIM-RADAR DEPICTIONS FOR THE AFTERNOON HOURS.
TO BEGIN WITH THE BIGGEST LIMITING FACTOR FOR TODAY...INSTABILITY
WILL BE IN QUESTION. GIVEN THE EXPECTED CLOUD COVER...AND EVEN
PRECIPITATION IN SOME PLACES...THE SURFACE TEMP FORECAST IS ON THE
LOW SIDE OF GUIDANCE. GIVEN THE THERMAL PROFILE...MLCAPE WILL
STRUGGLE TO REACH 1000 J/KG...WITH THE MOST INSTABILITY FORECAST
TO BE IN THE SOUTHEASTERN PARTS OF THE CWA. IN THE
NORTHWEST...WHERE TEMPS WILL BE THE COOLEST...INSTABILITY WILL BE
EVEN LESS (500 J/KG OR SO). SOUNDINGS ARE RELATIVELY MOIST THROUGH
THEIR DEPTH...WITH RATHER LOW LCL HEIGHTS (AROUND 2000-3000 FEET
AGL) FORECAST ON THE GFS/NAM (THE RAP13 APPEARS A BIT DRIER).
BECAUSE OF THE MOIST CONDITIONS...THE CAPE PROFILE IS NARROW.
UNLIKE YESTERDAY...THE OVERALL FORCING ENVIRONMENT WILL BE MORE
FAVORABLE FOR CONVECTIVE DEVELOPMENT...EVEN IF INSTABILITY IS
WEAK. WIND SHEAR IS ALSO SOMEWHAT OF A STRENGTH FOR
TODAY...ALTHOUGH MODEL-TO-MODEL ASSESSMENT ON SHEAR VALUES IS NOT
IN AS GOOD OF CONSENSUS AS IS USUALLY THE CASE. MOST OF THE SHEAR
WILL BE FAIRLY UNIDIRECTIONAL (ALL IN THE TOP-RIGHT QUADRANT OF
THE HODOGRAPH)...BUT WITH A DECENT CHANGE IN SPEED. 30-40 KNOTS OF
DEEP LAYER SHEAR WILL BE PRESENT...WITH 15-25 KNOTS IN THE 0-1KM
LAYER. 0-3KM SRH VALUES WILL GET INTO THE 100-200 RANGE...SO THERE
WILL CERTAINLY BE SOME POTENTIAL FOR ROTATING STORMS. THIS COULD
BE ENHANCED BY BOUNDARY INTERACTIONS OR AREAS OF BACKING SURFACE
WINDS (PERHAPS FURTHER NORTH AND CLOSER TO THE SURFACE LOW).
THE LACK OF INSTABILITY...ESPECIALLY IN THE HAIL GROWTH
ZONE...WILL LIMIT THE POTENTIAL FOR LARGE HAIL (PERHAPS OUTSIDE OF
A STRONGER / ROTATING UPDRAFT). THE THREAT FOR STRONG WINDS AND
TORNADOES DOES APPEAR TO EXIST...BUT THE THERMODYNAMIC ENVIRONMENT
SEEMS TO LIMIT THIS FROM BEING A HIGHER-END SEVERE EVENT. A
CLOUDIER/GRUNGIER MORNING WOULD SUPPORT AN ISOLATED SEVERE THREAT
WITH CLUSTERS OF STORMS CAPABLE OF STRONG WINDS AND MAYBE A BIT OF
ROTATION. THE OUTSIDE SHOT FOR TODAY WOULD BE A GREATER DEAL OF
BOUNDARY LAYER DESTABILIZATION (BETWEEN INSOLATION AND MOISTURE
ADVECTION)...WHICH WOULD BRING A GREATER RISK OF ALL THE SEVERE
MODES COMING TO THE TABLE. HOWEVER...GIVEN ALL THE EVIDENCE...THIS
FORECAST WILL LEAN TOWARD THE FORMER SOLUTION. THE HWO WILL FOLLOW
SUIT WITH A RELATIVELY TYPICAL-SOUNDING SEVERE THREAT WORDING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE SHORT TERM DISCUSSION WILL BE UPDATED SHORTLY.
PREVIOUS DISCUSSION FOLLOWS >
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO OVERSPREAD THE FA
DURING THE DAYTIME HOURS ON WEDNESDAY. THERE IS STILL SOME
QUESTION AS TO THE SEVERE POTENTIAL FOR WEDNESDAY. THERE IS BETTER
INSTABILITY ACROSS EASTERN PORTIONS OF THE FA FOR WEDNESDAY. IN
ADDITION STORMS WILL HOLD OFF A LITTLE LONGER ACROSS EASTERN
PORTIONS OF THE FA WHICH WILL ALLOW FOR SOME MORE HEATING. DUE TO
THIS BELIEVE THAT THE BETTER SEVERE THREAT WILL BE ACROSS EASTERN
PORTIONS OF THE FA FOR WEDNESDAY WITH THE MAIN THREATS BEING
DAMAGING WINDS AND LARGE HAIL. PRECIPITATION COVERAGE ACROSS THE AREA
WILL DIMINISH DURING THE LATE EVENING HOURS HOWEVER SOME ISOLATED
ACTIVITY WILL STILL REMAIN POSSIBLE. ADDITIONAL SHOWERS AND
THUNDERSTORMS WILL BEGIN TO MOVE INTO WESTERN PORTIONS OF THE FA
LATE IN THE OVERNIGHT HOURS WEDNESDAY NIGHT AS THE COLD FRONT
APPROACHES THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SHOWERS ARE LIKELY TO DEVELOP MAINLY OVER NORTHERN LOCATIONS ON
THURSDAY AS A SHARP UPPER TROUGH AND COOL AIRMASS PUSH THROUGH THE
GREAT LAKES AND OHIO VALLEY. FRIDAY WILL BE DRY AND COOL WITH HIGH
PRESSURE CROSSING THE AREA. DRY WEATHER SHOULD CONTINUE ON SATURDAY
FOR MOST OF THE AREA EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A
DEVELOPING FRONTAL BOUNDARY MAY CAUSE A FEW SHOWERS.
FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO
LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF
SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH
NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER.
SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY
WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND
SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY
ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE
SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS
SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES
SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA
TONIGHT.
LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS IN AN
INSTABILITY MINIMUM EARLY THIS MORNING. AS SUCH...THE LOW LEVEL
JET THAT IS FORECAST TO DEVELOP OVERNIGHT SHOULD PRODUCE SOME
SCATTERED SHOWERS AND PERHAPS A RUMBLE OF THUNDER.
FOR TODAY INTO THIS EVENING...THE PROSPECTS OF SHOWERS AND
THUNDERSTORMS WILL INCREASE THROUGH THE DAY AS DAYTIME HEATING
INTERACTS WITH LARGE SCALE SYNOPTIC LIFT. BEST CHANCE FOR
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE FROM MID AFTERNOON
INTO THE EVENING HOURS. HAVE PLACED THIS IN THE TAFS WITH A
PREDOMINANT MVFR -SHRA AND A VCTS/CB. AS STORMS BECOME MORE APPARENT
AND CAN BE TRACKED ON RADAR...TAFS WILL BE FINED TUNED
ACCORDINGLY. WITH A MOIST AIRMASS...SOME LOCAL MVFR CIGS AND IFR
VSBYS WILL BE POSSIBLE IN THUNDERSTORMS. DAYTIME HEATING/MIXING
WILL PRODUCE SOUTH/SOUTHWEST WINDS OF 10-15 KNOTS WITH GUSTS
AROUND 25 KNOTS.
FOR TONIGHT...A COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE
REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY.
HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS
AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT.
HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE
BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A
REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL LIKELY RESULT IN SOME
MVFR CIGS.
OUTLOOK...MVFR CONDITIONS POSSIBLE THURSDAY INTO THURSDAY EVENING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
1157 PM CDT TUE MAY 21 2013
.DISCUSSION...
THE 06Z TAF DISCUSSION IS INCLUDED BELOW.
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
CLOUDS WILL BE CLEARING SOON AT ALL OF THE TAF SITES...AND WITH
THE SATURATED CONDITIONS NEAR THE GROUND...THERE WILL BE SOME FOG
DEVELOPMENT. I THINK CONDITIONS WILL BE WORSE DOWN AT KMLC AND
KFSM WHERE RECENT HEAVY RAINS HAVE OCCURRED. NEVERTHELESS...VSBYS
WILL DROP DOWN TO IFR AND POSSIBLY LOWER FOR A TIME. VFR
CONDITIONS WILL PREVAIL ON WEDNESDAY EVERYWHERE.
LACY
&&
.PREV DISCUSSION... /ISSUED 917 PM CDT TUE MAY 21 2013/
..UPDATE...
DISCUSSION...
PRECIPITATION HAS MOVED EAST OUT OF THE ENTIRE FORECAST AREA
QUICKLY THIS EVENING. SKIES ARE CLEARING FROM THE WEST AS DRY AIR
PUSHES IN BEHIND THE DEPARTING UPPER SYSTEM. HAVE REMOVED POPS FOR
ALL BUT THE EASTERN MOST SLIVER OF THE CWA. HAVE ALSO CLEARED
SKIES A LITTLE FASTER OVERNIGHT. HAVE LEFT FORECAST MINIMUM
TEMPERATURES AS THEY WERE. UPDATED PRODUCTS HAVE ALL BEEN SENT.
PREV DISCUSSION... /ISSUED 648 PM CDT TUE MAY 21 2013/
DISCUSSION...
THE 00Z TAF DISCUSSION IS INCLUDED BELOW.
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
RAIN/STORMS ARE MOVING OUT...WITH SKIES CLEARING THIS EVENING. DUE
TO THE RECENT RAINS AND WET GROUND...SOME PATCHY FOG WILL LIKELY
DEVELOP. THINK THE FOG WILL BE MOST PROMINENT OVER SOUTHEAST OK
WHERE THE HEAVIEST RAINS FELL SO I HAVE BROUGHT KMLC DOWN TO IFR
VSBY. THE HYDROLAPSE BECOMES UNFAVORABLE FOR WIDESPREAD DENSE FOG
TONIGHT AS THE BOUNDARY LAYER DRIES OUT AFTER MIDNIGHT. SO FOR
NOW STAYED CONSERVATIVE ON VSBYS AT THE OTHER SITES.
LACY
PREV DISCUSSION... /ISSUED 312 PM CDT TUE MAY 21 2013/
DISCUSSION...
LINEAR MCS THAT HAS FORMED AHEAD OF COMPACT UPPER SYSTEM SURGING
ACROSS OK/TX IS CURRENTLY MOVING ACROSS PORTIONS OF SERN OK. THE
LINE HAS BEEN STRONG/MARGINALLY SEVERE SO FAR...AND STILL COULD SEE
SOME 60+ MPH WIND GUSTS OVER THE NEXT FEW HOURS. HRRR HAS SHOWN A
VERY GOOD HANDLE ON THE COMPLEX...WITH THE LEADING EDGE EXITING OUR
FORECAST AREA AROUND 22Z-23Z. CURRENT FLASH FLOOD WATCH IS SET TO
EXPIRE AT 00Z...ALTHOUGH MAY EXTEND IT A FEW MORE HOURS. WILL TAKE A
LAST LOOK AT RADAR BEFORE FINAL DECISION. OTHERWISE...PARTIALLY
CLEARING SKIES ALONG WITH DRIER LOW-LEVEL AIR WILL ALLOW TEMPS TO
FALL INTO THE 50S FOR MUCH OF THE AREA.
WEAK SURFACE BOUNDARY MAY BE PRESENT ACROSS THE AREA ON
WEDNESDAY...ALTHOUGH ATMOSPHERE SHOULD BE TOO DRY AND WORKED OVER TO
SUPPORT PRECIPITATION.
UPPER PATTERN WILL BECOME INCREASINGLY AMPLIFIED BY MID-TO-LATE
WEEK...WITH RIDGING THROUGH THE PLAINS SANDWICHED BY DEEP UPPER
SYSTEMS ACROSS THE PAC NW AND THE EAST COAST. MODELS SUGGEST THAT
SEVERAL WEAK WAVES WILL MOVE INTO THE MEAN RIDGE POSITION...WITH AT
LEAST SOME LOW POPS WARRANTED ACROSS WRN SECTIONS IN THE VERY
WARM/MOIST AIRMASS.
UPPER RIDGE SHOULD FLATTEN SOME ACROSS THE SRN/CENTRL PLAINS GOING
INTO THE WEEKEND. WITH THE FORECAST AREA ALONG THE SRN EDGE OF THE
STRONGER UPPER FLOW...SHOULD SEE PERIODIC SHOWER/THUNDERSTORM
EPISODES...ESPECIALLY ACROSS NE OK/NW AR. TOUGH TO PINPOINT WHICH
DAY WILL HAVE THE BEST CHANCES...SO HAVE MAINTAINED GENERAL CHANCE
POPS FOR ABOUT THE NRN HALF OF THE AREA FOR THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 55 81 58 78 / 10 0 10 20
FSM 58 83 62 81 / 20 10 10 10
MLC 55 83 61 84 / 10 0 10 20
BVO 52 81 54 77 / 10 0 10 20
FYV 54 79 55 76 / 20 10 10 10
BYV 56 79 55 77 / 30 10 10 10
MKO 55 82 60 79 / 10 10 10 20
MIO 54 78 56 78 / 10 10 10 10
F10 55 82 61 79 / 10 0 10 20
HHW 60 85 64 85 / 10 0 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
246 AM CDT WED MAY 22 2013
.DISCUSSION...
CURRENT SETUP...UPPER TROUGH TAKING ON NEGATIVE TILT THROUGH THE MID-
LEVELS BASED ON LATEST RUC WITH THE COLDER AIR ALOFT REMAINING
BACK OVER CENTRAL PLAINS NOSING DOWN INTO ARKANSAS. A 35 TO 40
KNOT LOW LEVEL JET WAS CONTINUING TO FEED MOIST PLUME INTO MIDDLE
TENNESSEE. WIND FIELD LOOKS TO BE UNIDIRECTIONAL WITH SPEED SHEAR IN
THE LOWER TROPOSPHERE. UPPER LEVEL JET JUST RUNNING NORTH TO SOUTH
FROM ABOUT TEXARKANA NORTHWARD INTO IOWA WITH A 65 KNOT MID LEVEL
JET CUTTING ACROSS CENTRAL ARKANSAS. ON-GOING CONVECTION CURRENTLY
ACROSS FAR WESTERN KENTUCKY...WESTERN TENNESSEE AND DOWN THROUGH
MISSISSIPPI...BEEN SHOWING SIGNS OF WEAKENING LAST COUPLE OF HOURS
AS CLOUD TOPS CONTINUE TO WARM.
WITH THE CURRENT SETUP LOOKS LIKE SHOWERS AND STORMS WILL BE
LIKELY DURING THE DAY...WITH A FEW STRONG TO SEVERE STORMS
POSSIBLE...ESPECIALLY MID-DAY THROUGH THE AFTERNOON AND INTO THE
EARLY EVENING HOURS. THINK THE MAIN THREAT WILL BE DAMAGING WINDS AND
LARGE HAIL BUT ISOLATED TORNADOES ARE ALSO POSSIBLE. EVEN THOUGH
THE WIND FIELDS ARE UNIDIRECTIONAL THE SWEAT INDEX CLIMBS TO 362
AT 18Z AND 413 BY 00Z WITH MID-LEVEL DRYING IN PLACE DURING THE
MID-DAY THROUGH THE AFTERNOON/EARLY EVENING.
ON THURSDAY A SHORT WAVE ON THE BACK SIDE OF UPPER TROUGH WILL
DROP DOWN THROUGH THE OHIO VALLEY AND BRING A CHANCE FOR SHOWERS
AND ISOLATED THUNDERSTORMS MAINLY TO THE NORTHEAST HALF DURING THE
AFTERNOON WITH A SLIGHT CHANCE REMAINING ALONG THE PLATEAU
THURSDAY NIGHT. MUCH OF THE MEMORIAL DAY WEEKEND LOOKS DRY HOWEVER
MODELS HAVE BEEN DIFFERING. GFS HAS WARM FRONT DRAPED ACROSS THE
OHIO VALLEY THROUGH THE WEEKEND WHICH WOULD KEEP MID STATE
BASICALLY WARM AND DRY. THE EURO HAS WARM FRONT DRAPED THROUGH
WESTERN TENNESSEE INTO NORTHERN ALABAMA AND KEEPS SHOWERS AND
STORMS IN THE MID STATE JUST ABOUT EACH DAY THROUGH THE MEMORIAL
DAY WEEKEND. HAVE OPTED TO GO WITH GFS FOR THIS FORECAST PACKAGE.
HAVE BACKED OFF A TAD FROM MAV MOS ON HIGHS TODAY AND WENT CLOSER
TO THE MET DUE TO CLOUD COVER AND SHOWER/STORM CHANCES. STAYED
CLOSE TO MOS GUIDANCE THROUGH REMAINDER OF FORECAST.
BOYD
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 79 61 78 52 / 60 30 20 10
CLARKSVILLE 76 58 76 49 / 60 20 20 10
CROSSVILLE 76 59 73 51 / 70 50 30 20
COLUMBIA 79 61 80 54 / 60 30 20 10
LAWRENCEBURG 78 60 80 55 / 60 30 20 10
WAVERLY 77 59 77 50 / 60 20 20 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
BOYD
01
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1242 AM CDT WED MAY 22 2013
.DISCUSSION...SEE AVIATION SECTION FOR 06Z TAFS.
&&
.AVIATION...LOOP OF KCRP RADAR SHOWS OUTFLOW BOUNDARY/FRONT MOVING
SOUTH AT 20 MPH INTO THE VICTORIA CROSSROADS REGION. LOW STRATUS HAS
MOVED INTO THE COASTAL PLAINS WITH CEILINGS RANGING FROM IFR IN THE
COASTAL BEND TO LOW END MVFR IN THE VICTORIA CROSSROADS. EXPECT THE
BOUNDARY WILL STALL BEFORE MOVING INTO THE COASTAL WATERS OR COASTAL
BEND LATER DURING THE OVERNIGHT. EAST-SOUTHEASTERLY LOW LEVEL FLOW
WILL PUSH LOW CLOUDS WESTWARD INTO THE BRUSH COUNTRY REACHING LRD
AREA BY 09Z. ONLY PLACED A MENTION OF LIGHT SHOWERS IN THE VCT TAF
BEHIND THE FRONT EARLY THIS MORNING. MVFR CEILINGS WILL SLOWLY LIFT
DURING THE MORNING HOURS AND SCATTER OUT BY 18Z AREA-WIDE. VFR CONDS
WILL EXIST INTO THE EVENING HOURS WEDNESDAY WITH MVFR CIGS RETURNING
TO THE COASTAL PLAINS BY 02-03Z THURSDAY.
&&
.PREV DISCUSSION... /ISSUED 906 PM CDT TUE MAY 21 2013/
DISCUSSION...CONVECTION HAS FAILED TO DEVELOP AS OF WRITING AS SSW
FLOW FROM H95 TO H7, PER 00Z AREA RAOBS, IS LIKELY NEGATING CONVECTIVE
DEVELOPMENT. LATEST AVAILABLE HRRR AND 18Z TTU WRF ALSO INDICATE
ONLY LOW CHANCES OF PRECIP DEVELOPING TONIGHT. THUS...HAVE LOWERED
POPS FOR TONIGHT AREAWIDE. STILL THINK A THIN BAND OF SHOWERS AND
A FEW RUMBLES OF THUNDER WILL DEVELOP OVERNIGHT...PRIMARILY ACROSS
NORTHERN AND NE ZONES. WILL CONTINUE TO MONITOR SITUATION THROUGH
THE NIGHT. OTHERWISE...ONLY OTHER CHANGE OF SIGNIFICANCE WAS TO
INCLUDE MENTION OF HAZE AND SMOKE FARTHER INLAND TONIGHT AS SMOKE
FROM AGRICULTURAL FIRES OVER STATE OF YUCATAN MEX CONTINUES TO
IMPACT S TX. AIR PARTICULATES WILL LIKELY POOL ALONG STALLING WEAK
SFC FRONT ACROSS NORTHERN ZONES TONIGHT RESULTING IN A
CONTINUATION OF HAZE/SMOKINESS THROUGH WEDNESDAY. UPDATED PRODUCTS
TO BE SENT SHORTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 75 92 75 91 76 / 10 10 10 10 10
VICTORIA 73 90 74 89 73 / 10 10 10 10 10
LAREDO 76 98 75 96 75 / 10 10 10 10 10
ALICE 73 93 75 91 75 / 10 10 10 10 10
ROCKPORT 75 86 75 85 76 / 10 10 10 10 10
COTULLA 73 98 74 96 74 / 10 10 10 10 10
KINGSVILLE 74 92 75 91 75 / 10 10 10 10 10
NAVY CORPUS 75 84 75 84 75 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...AVIATION
AREA FORECAST DISCUSSION...ISSUED BY WFO RALEIGH NC
NWS BLACKSBURG VA
340 AM EDT WED MAY 22 2013
.SYNOPSIS...
A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO
THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT
THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 AM EDT WEDNESDAY...
A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL
FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST
FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE
RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING
WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA.
HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION
THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE
ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE
CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE
AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS
AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING
NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL
CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON.
EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT
THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE
PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS
INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE
INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN
00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS
CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY
IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH
FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY
THIS EVENING TO COVER THIS POTENTIAL.
THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF
OUR REGION TODAY INTO TONIGHT.
CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT
AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS
TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID
80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID
60S SE.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 320 AM EDT WEDNESDAY...
A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION
BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE
CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY.
OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT
THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE.
LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY
ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION
COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM
PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE
PIEDMONT AND TIDEWATER AREAS OF VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
FRIDAY NIGHT AND SATURDAY:
QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM
FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST
OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE
BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD
GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 202 AM EDT WEDNESDAY...
THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT
HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH
SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE.
THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN
SHOWERS ARE EXPECTED THIS MORNING.
A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET
OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES
WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON
CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH
POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN
SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB
WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER
SCTD/BKN 5-6K FT CU FIELDS.
THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD
OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY.
THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG.
HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY
AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...PWB
SHORT TERM...PWB/BSD/WP
LONG TERM...WP
AVIATION.../WFORAH
AREA FORECAST DISCUSSION...ISSUED BY WFO RALEIGH NC
NWS BLACKSBURG VA
320 AM EDT WED MAY 22 2013
.SYNOPSIS...
A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO
THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT
THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 320 AM EDT WEDNESDAY...
A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL
FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST
FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE
RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING
WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA.
HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION
THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE
ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE
CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE
AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS
AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING
NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL
CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON.
EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT
THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE
PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS
INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE
INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN
00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS
CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY
IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH
FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY
THIS EVENING TO COVER THIS POTENTIAL.
THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF
OUR REGION TODAY INTO TONIGHT.
CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT
AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS
TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID
80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID
60S SE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 AM EDT WEDNESDAY...
A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION
BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE
CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY.
OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT
THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE.
LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY
ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION
COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM
PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE
PIEDMONT AND TIDEWATER AREAS OF VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 202 AM EDT WEDNESDAY...
THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT
HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH
SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE.
THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN
SHOWERS ARE EXPECTED THIS MORNING.
A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET
OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES
WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON
CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH
POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN
SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB
WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER
SCTD/BKN 5-6K FT CU FIELDS.
THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD
OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY.
THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG.
HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY
AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...PWB
SHORT TERM...PWB/WP
LONG TERM...WP
AVIATION.../WFORAH
AREA FORECAST DISCUSSION...ISSUED BY WFO RALEIGH NC
NWS BLACKSBURG VA
202 AM EDT WED MAY 22 2013
.SYNOPSIS...
AN UPPER LEVEL AREA OF LOW PRESSURE WILL DRIFT EAST AND OFFSHORE
OVERNIGHT. A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE
CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL
PUSH A COLD FRONT THROUGH THE AREA THURSDAY...FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 915 PM EDT TUESDAY...
BAND OF WEAKENING CONVECTION ASSOCIATED WITH OLD OUTFLOW BAND TO
THE WEST CONTINUES TO FADE ALONG THE WESTERN SLOPES ATTM WHILE NEW
OUTFLOW HAS GIVEN RISE TO ADDED SHRA/TSRA OVER THE WESTERN RIDGES.
LATEST MESO ANALYSIS SHOWS STILL ENOUGH INSTABILITY TO KEEP STORMS
GOING A WHILE LONGER MOUNTAINS WITH SOME OF THIS COVERAGE PERHAPS
DEVELOPING ACROSS THE BLUE RIDGE WHERE THE BEST LEFTOVER CAPES
EXIST. APPEARS THE OVERALL SEVERE THREAT SHOULD SLOWLY FADE PER
LOSS OF HEATING BUT LOW WET BULBS AND LOTS OF DRY AIR ALOFT OFF
EVENING SOUNDINGS STILL SUPPORT AT LEAST ISOLATED SEVERE POTENTIAL
THROUGH MIDNIGHT ESPCLY IF STORMS BECOME MORE LINEAR. THEREFORE
NUDGED UP POPS TO LOW LIKELYS FAR WEST OVER THE NEW FEW HOURS
WHILE KEEPING A SCATTERED NATURE FARTHER EAST DESPITE THE LACK OF
COVERAGE OFF THE LATEST HRRR SHORTLY AFTER MIDNIGHT. LOW LEVELS
ESPCLY EAST SHOW A BIT MORE DRYING THIS EVENING WITH SOME LIGHT
MIXING ONGOING WHICH SHOULD SLOW DOWN FOG FORMATION UNTIL LATE
EXCEPT WHERE RAINFALL HAS ALREADY OCCURRED. HOWEVER MOIST
DEWPOINTS WILL HOLD TEMPS MOSTLY IN THE MUGGY 60S WITH ONLY THE
DEEPER VALLEYS AND SPOTS SEEING SHOWERS PERHAPS FALLING INTO THE
50S LATE.
WARM AND HUMID CONDITIONS CONTINUE ON WEDNESDAY IN THE SOUTHERLY
FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH.
INCREASED POPS FROM WEST TO EAST ON WEDNESDAY...WITH HIGHEST POPS
ALONG WESTERN MOUNTAINS. THE SWODY2 (DAY TWO CONVECTIVE OUTLOOK)
HAS THE SLIGHT RISK JUST TO OUR WEST ON WEDNESDAY. PLAYED HIGHS
TEMPERATURES COOLER ON WEDNESDAY WITH READINGS FROM THE MID 70S IN
THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 255 PM EDT TUESDAY...
HAVE A COUPLE DAYS MORE OF HUMID WEATHER BEFORE FRONT SWINGS ACROSS
THURSDAY AND BRINGS A RETURN TO LOWER DEWPOINTS.
UNTIL THEN...NO MAJOR CHANGES TO THE FORECAST. WEDNESDAY NIGHT A
PIECE OF SHORTWAVE ENERGY ARRIVES ACROSS THE CENTRAL APPALACHIANS
WHICH CREATES AN AREA OF SHOWERS AND STORMS...MAINLY AFFECTING THE
WRN EDGE OF THE FORECAST AREA. THE BETTER PUSH OF THE FRONT ON
THURSDAY COMBINED WITH BETTER UPPER SUPPORT SHOULD BRING SOME
ENHANCED THREAT OF SHOWERS AND STORMS. TIMING OF THIS FRONT DOES
VARY SOMEWHAT FROM THE MODELS BUT ENOUGH AGREEMENT TO HAVE HIGH
CHANCE TO LIKLEY IN THE AREA THURSDAY. TIMING ALSO GIVES ISSUES TO
SVR THREAT. ATTM...EXPECT A LINE OF SHRA/TSRA TO BE IN THE MTNS IN
THE MORNING AND MOVING INTO THE PIEDMONT BY EARLY AFTERNOON. NOT
SEEING A LOT OF HEATING AS CLOUDS WILL BE GENEROUSLY SPREAD. ONE
AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC
PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT
THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF
VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 202 AM EDT WEDNESDAY...
THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT
HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH
SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE.
THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN
SHOWERS ARE EXPECTED THIS MORNING.
A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET
OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES
WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON
CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH
POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN
SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB
WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER
SCTD/BKN 5-6K FT CU FIELDS.
THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD
OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY.
THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG.
HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY
AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/JH/KK
SHORT TERM...WP
LONG TERM...WP
AVIATION.../WFORAH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 AM CDT WED MAY 22 2013
.SHORT TERM...(TODAY AND FRIDAY)
ISSUED AT 309 AM CDT WED MAY 22 2013
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH TONIGHT...
THEN POSSIBLE PATCHY FROST OVER CENTRAL WISCONSIN THURSDAY NIGHT.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL LOW OVER
THE NORTHERN PLAINS AND SHORTWAVE TROUGHS ROTATING AROUND THE UPPER
LEVEL LOW. LATEST MOSAIC RADAR INDICATING SCATTERED SHOWERS
EXTENDING FROM LAKE SUPERIOR INTO SOUTHWEST MINNESOTA AND ANOTHER
AREA OF SHOWERS AND THUNDERSTORMS FROM WESTERN ILLINOIS INTO
SOUTHERN LAKE MICHIGAN.
THE 22.00Z GFS/NAM ARE IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL
FLOW THROUGH FORECAST PERIOD. BOTH MODELS ARE IN DECENT AGREEMENT
LIFTING SHORTWAVE TROUGH OVER MISSOURI AND EASTERN KANSAS
INTO SOUTHERN WISCONSIN TODAY. THE 22.00Z GFS/NAM AND 22.03Z RAP ARE
IN AGREEMENT IN INCREASING PV ADVECTION...QG FORCING AND VERTICAL
MOTION OVER THE FORECAST AREA 12-18Z TODAY AND DEVELOP
PRECIPITATION OVER MUCH OF THE FORECAST AREA BY 18Z TODAY.
CONFIDENCE IS INCREASING THE FORECAST AREA WILL SEE PRECIPITATION
DEVELOP OVER FORECAST AREA BY 18Z. THE DETERMINISTIC MODELS INDICATE
0-6KM MOST UNSTABLE CAPE 300-500 J/KG OVER SOUTHEASTERN HALF OF THE
FORECAST AREA AFTER 15Z TODAY. WILL CONTINUE TO MENTION ISOLATED
THUNDERSTORMS.
THE 22.00Z GFS/NAM SUGGEST UPPER LEVEL LOW WEAKENS AND DRIFTS SLOWLY
EAST INTO THE GREAT LAKES REGION...AS AN UPPER LEVEL TROUGH
DIGS OVER EASTERN GREAT LAKES REGION TONIGHT. WITH SURFACE RIDGE
BUILDING INTO SOUTHERN ONTARIO AND THE WESTERN GREAT LAKES REGION...
CLOUDS AND PRECIPITATION WILL DIMINISH FROM NORTH TO SOUTH ACROSS
FORECAST AREA AFTER 06Z THURSDAY.
DRY NORTHEASTERLY FLOW ALOFT DEVELOPS OVER FORECAST AREA THURSDAY.
THE 22.00Z GFS/NAM BUFKIT SOUNDINGS ARE INDICATING FORECAST AREA
MIXING UP TO 825MB BY 21Z. THIS SHOULD ALLOW FOR DEWPOINTS TO FALL
INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS MUCH OF THE FORECAST AREA
THURSDAY AFTERNOON.
NEXT CONCERN IS LOW TEMPERATURES AND PATCHY FROST FRIDAY MORNING...
WITH THE COMBINATION OF SURFACE RIDGE CENTERED AND DRY AIRMASS OVER
FORECAST AREA...TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE
30S ACROSS PORTIONS OF CENTRAL WISCONSIN. PATCHY FROST WILL BE
POSSIBLE ACROSS THIS PART OF THE FORECAST AREA.
.LONG TERM...(FRIDAY NIGHT INTO TUESDAY)
ISSUED AT 309 AM CDT WED MAY 22 2013
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH FORECAST
PERIOD. THE 22.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON TIMING OF
SHORTWAVE TROUGHS OVER-TOPPING UPPER LEVEL RIDGE OVER THE CENTRAL
UNITED STATES AND PLACEMENT OF THE SURFACE RIDGE OVER THE
GREAT LAKES REGION. WITH THIS...CONFIDENCE IN FORECAST IS LOW AND
WILL CONTINUE WITH CONSISTENCY OF PRECIPITATION CHANCES THROUGH
FORECAST PERIOD. TEMPERATURES WILL CLIMB INTO THE 60S FOR THE
MEMORIAL DAY WEEKEND AND BE IN THE 70S TUESDAY...AS THE
DETERMINISTIC MODELS INDICATE WARMER AIR ALOFT TO FILTER INTO THE
REGION BY 00Z TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1131 PM CDT TUE MAY 21 2013
THE MAIN FOCUS AT THE TAF SITES IS WITH THE POTENTIAL FOR MVFR TO
IFR FLIGHT CONDITIONS AND RAIN SHOWERS AS A LOW PRESSURE SYSTEM
MOVES THROUGH THE REGION. THIS LOW IS CURRENTLY TO THE NORTHWEST
OF THE REGION BUT IS STARTING TO SINK TO THE SOUTHEAST. ALL OF THE
MVFR TO IFR CEILINGS ARE CURRENTLY TO THE NORTH AND WEST OF THIS
LOW AND ARE EXPECTED TO GET INTO THE REGION LATER WEDNESDAY
MORNING. THE EXACT TIMING OF THAT IS IN DOUBT...BUT RST SHOULD SEE
SOME IFR CEILINGS MOVE IN AROUND DAYBREAK WITH MVFR POSSIBLE INTO
LSE AROUND THE SAME TIME. SOME SHOWERS ARE EXPECTED TO DEVELOP IN
THE MORNING HOURS AS WELL AND LAST THROUGH MUCH OF THE DAY BEFORE
DIMINISHING IN THE EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....DTJ
LONG TERM......DTJ
AVIATION.......HALBACH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MDT TUE MAY 21 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM MDT TUE MAY 21 2013
EXTENDED THE WIND ADVISORY UNTIL 6 PM MDT FOR MOST OF THE NEBRASKA
PANHANDLE. AT 2 PM MDT WINDS WERE GUSTING TO 51 MPH AT SCOTTSBLUFF
AND 44 MPH AT ALLIANCE. WINDS SHOULD BEGIN A SLOW DECREASE THE
REST OF THIS AFTERNOON AND THEN DROP OFF MORE QUICKLY THIS
EVENING.
WINDS WILL SHIFT TO THE NORTHEAST OVER EASTERN AREAS TONIGHT AND
THEN TURN TO THE SOUTHEAST WEDNESDAY. THIS WILL BEGIN TO ALLOW LOW
LEVEL MOISTURE TO ADVECT WESTWARD WHICH MAY ALLOW FOR INCREASING
CHANCES OF THUNDERSTORMS THROUGH THE WEEK. KEPT A SLIGHT CHANCE
FOR SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND ADJACENT
PLAINS FOR WEDNESDAY AFTERNOON. MODEL SOUNDINGS SHOWING STEEP
LAPSE RATES WITH LITTLE TO NO CONVECTIVE INHIBITION. INSTABILITY
IS NOT ALL THAT GREAT SO MAINLY LOOKING AT SHOWERS WITH A FEW WEAK
THUNDERSTORMS. MODELS DO SHOW AN ELEVATED WARM FRONT MOVE EAST
ACROSS THE FORECAST AREA WEDNESDAY NIGHT. THERE MAY BE ENOUGH
INSTABILITY AND LIFT TO KEEP ISOLATED SHOWERS AND WEAK
THUNDERSTORMS PECULATING INTO THE NIGH-TIME WHILE SHIFTING EAST
INTO WESTERN NEBRASKA.
SOUTH TO SOUTHEAST WINDS SHOULD BEGIN TO RAMP UP WEDNESDAY NIGHT
AND THURSDAY. MODELS HAVE BEEN TRENDING STRONGER WITH LOW LEVEL
FLOW THURSDAY. NAM AND GFS BUFKIT SOUNDING AT LUSK SHOWING 50 KT
WINDS A FEW THOUSAND FEET ABOVE GROUND LEVEL THURSDAY AFTERNOON.
SOUNDINGS ALSO SHOWING A VERY STRONG LOW LEVEL INVERSION DUE IN
PART TO THE MOIST LOW LEVEL FLOW. KEPT A CHANCE FOR THUNDERSTORMS
MAINLY OVER THE MOUNTAINS THURSDAY. MOST LIKELY A FEW STORMS WILL
DEVELOP OVER THE LARAMIE RANGE...BUT WITH SUCH A STRONG CAP IN
PLACE...STORMS MAY HAVE A TOUGH TIME MOVING INTO LOWER ELEVATIONS.
ALONG WITH THE INVERSION EXPECTING A LOT OF STRATUS THURSDAY.
STRATUS SHOULD PUT A LID ON TEMPERATURES. FOLLOWED THE PREVIOUS
FORECAST SHIFT IN LOWERING DAYTIME HIGHS FOR THURSDAY. ALSO WARMED
THE LOW A BIT WEDNESDAY NIGHT AND THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 325 PM MDT TUE MAY 21 2013
FIRST UPPER SHORTWAVE EJECTING FROM PAC NW UPPER LOW WILL MOVE
ACROSS THE AREA FRIDAY MORNING. TIMING SUCH THAT THERE MAY BE A BIT
OF CONVECTION OVER MAINLY THE PANHANDLE BUT IF SFC BOUNDARY MOVES
FAR ENOUGH EAST THE ACTIVITY WOULD BE EAST OF THE CWA. WILL KEEP
SOME LOW POPS IN PLACE UNTIL BETTER CERTAINTY. SW FLOW ALOFT
REMAIN IN PLACE OVER THE CWA OVER THE WEEKEND INTO EARLY NEXT WEEK
SO SOME AFTERNOON AND EVENING CONVECTION WILL CONTINUE TO BE A
POSSIBILITY...THOUGH TIMING WILL BE DIFFICULT. ECMWF DEPICTING IT
PRETTY MUCH DAILY WHILE GFS DRIER. WILL KEEP POPS WHERE IT LOOKS
MORE FAVORABLE SUCH AS SUNDAY AND MONDAY. TEMPERATURES WILL BE
ON THE WARM SIDE FOR MUCH OF THE PERIOD...GENERALLY A LITTLE ABOVE
SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1057 PM MDT TUE MAY 21 2013
LATEST SREF AND HRRR GUIDANCE SHOWING SOME WRAP AROUND LOW CLOUDS
MAKING IT INTO KCDR AND KAIA OVERNIGHT. UPSTREAM OBSERVATIONS IN
SOUTH DAKOTA REPORTING CEILINGS DOWN AROUND 1500 FEET...SO THEIR
FORECAST SEEMS REASONABLE. WENT AHEAD AND LOWERED CEILINGS AT KCDR
AND KAIA TONIGHT. VFR ELSEWHERE.
&&
.FIRE WEATHER...
ISSUED AT 325 PM MDT TUE MAY 21 2013
WINDS WILL DROP OFF QUICKLY THIS EVENING AND BECOME LIGHT. WINDS
WILL REMAIN ON THE LIGHT SIDE MAINLY IN THE 10 TO 15 MPH RANGE
WEDNESDAY BUT WILL BEGIN TO INCREASE WEDNESDAY NIGHT...WITH STRONG
SOUTHEAST WINDS ALONG AND EAST OF THE LARAMIE RANGE FOR THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MAINLY BE CONFINED TO
THE MOUNTAINS WEDNESDAY AND THURSDAY AFTERNOON.
WEATHER CONDITIONS WILL VARY GREATLY FROM WEST TO EAST OVER THE
FORECAST AREA LATE THIS WEEK AND WEEKEND. RELATIVELY MOIST
CONDITIONS WILL BE FOUND EAST OF THE LARAMIE RANGE UNDER SOUTH TO
SOUTHEAST LOW LEVEL FLOW...WHILE WEST OF THE LARAMIE RANGE DRY
SOUTHWEST FLOW WILL DOMINATE PRODUCING LOW HUMIDITY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...LIEBL
LONG TERM...RE
AVIATION...CLAYCOMB
FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1104 AM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN PASS
THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE
WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HRRR IS THE ONLY MODEL WHICH SHOWS SHALLOW BACK DOOR FRONT MAKING
PROGRESS AS FAR TO THE S AND W AS IT DID...AND HOLDS THE FRONT
PRIMARILY TO OUT S AND W THROUGH MOST OF THE AFTERNOON. SUSPECT
THAT EVEN THE HRRR IS TOO FAST TO ERODE MARINE LAYER.
EXPECT MOST OF THE AREA TO BE CLOUDY THROUGH THE DAY AS A RESULT.
FOR NOW HAVE SIGNIFICANTLY SCALED BACK ON POPS FOR
TODAY...ESPECIALLY ACROSS THE SE 1/2 OF THE CWA...AND RESTRICTED
PROBABILITY OF THUNDER TO SLIGHT CHANCE AND THEN ONLY OVER NW
ZONES...AS STILL CANNOT RULE OUT CONVECTION FORMING OUTSIDE THE
CWA THEN MOVING IN.
TEMPERATURES LOWERED REFLECTING BLEND OF HRRR 2-METER TEMPERATURES
AND LAV GUIDANCE - WHICH IS NOT ALL THAT BAD. DID NOT GO AS WARM
AS THIS WOULD SUGGEST THOUGH OVER NW ZONES - GIVEN SUSPICION THAT
MARINE LAYER HOLDS ON. WILL HAVE BETTER IDEA WHICH WAY TO PLAY
NW/FAR W ZONES WITH NEXT UPDATE EARLY THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
HAVE CONCERN THAT IF THE MARINE LAYER DOES NOT DISSIPATE/FRONT
LIFT TO THE N BY THIS EVENING - THAT THE MARINE LAYER WILL
MAINTAIN ITSELF OVER MOST IF NOT ALL THE AREA TONIGHT. WILL
CONTINUE TO MONITOR TRENDS - BUT COULD END UP MAKING SIGNIFICANT
CHANGES TO TONIGHTS FORECAST IF CURRENT TRENDS HOLD.
SCT-ISOLD SHOWERS AND TSTMS THIS EVENING. CONVECTION SHOULD BE
SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE. SHOWERS
AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS THE
UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACH THE
AREA.
HIGHS ON THURSDAY IN THE MID TO UPPER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE
EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM
SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE
COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES
AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS
AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD
RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH
MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE
ALSO TRENDED A BIT SLOWER WITH PRECIPITATION GRADUALLY TAPERING
OFF FRI AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL
NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS
DOWN EVEN FURTHER.
AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION
THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO
MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM
DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF
APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD
DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT
WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED
WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF
INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE
COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE
THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN
THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD
PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH
FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS.
AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED
HIGHER AMOUNTS.
A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD
ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO
THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES
SEVERAL DEGREES BELOW SEASONABLE LEVELS.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS MORNING.
AS A RESULT...HAVE GONE MORE PESSIMISTIC WITH THE FORECAST
THROUGH THE DAY...SHOWING IMPROVEMENT IN CIGS AND VSBY GENERALLY
AROUND 17Z-21Z. HOWEVER CONFIDENCE IN THIS
IMPROVEMENT...ESPECIALLY FOR CIGS...IS LOW. POTENTIAL FOR WINDS
TO STAY LIGHTER / MORE EASTERLY FOR A LONGER PERIOD THAN INDICATED
IN TAFS AS WELL.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON...GENERALLY AT KSWF AND PERHAPS KHPN. MARINE LAYER
LIKELY TO KEEP TS AWAY FROM TERMINALS FARTHER SE.
IT COULD BE ANOTHER TRICKY NIGHT FORECASTING VFR/IFR CONDITIONS.
LATEST GUIDANCE IS HINTING AT IFR OR LESS CONDITIONS AT THE
OUTLYING TERMINALS...HOWEVER GUIDANCE DIFFERS ON TIMING AND JUST
HOW LOW CIGS AND VSBYS GET. WILL HOLD OFF IN LOWERING CONDITIONS
TOO MUCH WITH LOW CONFIDENCE HOWEVER THIS WILL NEED TO BE
MONITORED. HIGHEST CONFIDENCE OF IFR OR LOWER CONDITIONS WILL BE
AT KGON.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2
HOURS LONGER THAN INDICATED IN TAF.
KLGA FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2
HOURS LONGER THAN INDICATED IN TAF.
KEWR FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2
HOURS LONGER THAN INDICATED IN TAF.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES
SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER FOR 1-2 HOURS
LONGER THAN INDICATED IN TAF.
KHPN FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AROUND
18-21Z...ESPECIALLY FOR CIGS.
KISP FCSTER COMMENTS: LOW POTENTIAL FOR CIGS/VSBY TO IMPROVE TO
MVFR OR HIGHER LEVELS AROUND 17-18Z. WIND SPEEDS MAY BE 1-2 HOURS
SLOWER TO INCREASE THAN SHOWN IN TAF.
.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN
FOG AND STRATUS.
.SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR
WITH NW WINDS INCREASING TO 20-30KT.
.SUNDAY...VFR WITH NW WINDS 20-25KT.
&&
.MARINE...
BASED ON HRRR AND LATEST TRENDS IN OBSERVATIONS AND WEB-CAMS HAVE
EXTENDED THE DENSE FOG ADVISORY FOR THE COASTAL OCEAN ZONES...NY
HARBOR AND THE SOUTH SHORE BAYS OF LONG ISLAND THROUGH 22Z. GIVEN
NO RESTRICTIONS OF 1NM OR LESS IN VISIBILITY EVIDENT ON SOUND OR
EASTERN BAYS OF LONG ISLAND...HAVE CANCELLED THE DENSE FOG
ADVISORY THERE.
SEAS ARE NOT INCREASING AS FAST AS FORECAST...SO HAVE ADJUSTED
DOWNWARD A FOOT OR SO ACROSS MOST OCEAN AREAS INTO THIS EVENING.
SEAS SLOWLY BUILD THIS AFTERNOON/EVENING N TO SCA LEVELS AND
REMAIN ABOVE SCA LEVELS THROUGH THURSDAY. SW FLOW INCREASES OVER THE
COASTAL OCEAN WATERS TONIGHT AS WELL WITH SFC BOUNDARY LIFTING TO
NEAR THE LONG ISLAND COAST IF NOT FARTHER N.
A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY
THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE
WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS
THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE
SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY
SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS
SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH
SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST
THE MODELS.
&&
.HYDROLOGY...
SCT SHOWERS/TSTMS THIS EVENING WILL BE CAPABLE OF PRODUCING
LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC.
TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH
LOCALLY HIGHER AMOUNTS IN TSTMS.
SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE
THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN
RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS.
THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD
RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE
LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ338-345-
350-353-355.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT
THURSDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...24/NV
NEAR TERM...24/MALOIT/NV
SHORT TERM...24
LONG TERM...NV
AVIATION...BC/PICCA
MARINE...24/MALOIT/NV
HYDROLOGY...24/NV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1047 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY
INTO THE SAINT LAWRENCE VALLEY TOMORROW. WARM AND HUMID CONDITIONS
WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. A STRONG
COLD FRONT WILL MOVE SLOWLY THROUGH NEW YORK AND NEW ENGLAND INTO
THURSDAY NIGHT. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST
FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION...AS THE WEATHER
MAY STAY UNSETTLED INTO THE FIRST HALF OF THE MEMORIAL DAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM EDT... A STATIONARY FRONT REMAINS OVER ERN NY AND WRN
NEW ENGLAND...AS IT APPEARS IT WILL BEGIN TO LIFT TO THE N/NE INTO
THE EARLY PM...AS A SHORT-WAVE WITH SOME SCT SHOWERS AND ISOLD
THUNDERSTORMS IS APPROACHING FROM WRN-CNTRL NY. THE POPS ARE
GRADUALLY INCREASED IN THE LATE MORNING INTO THE EARLY PM.
STRATUS IS HANGING TOUGH THIS MORNING...AND SHOULD GRADUALLY ERODE
FROM SW TO NE. THE IS A BETTER AREA OF CLEARING OVER THE OH
VALLEY. THERE IS YET...ANOTHER SHORT-WAVE MOVING TOWARD WRN PA.
THIS DISTURBANCE MAY INCREASE THE POTENTIAL FOR SEVERE WX IN THE
LATE PM/EARLY EVENING...ESPECIALLY OVER WRN NY
WE HAVE BACK OFF THE SVR WX WORDING UNTIL AFTER 3 PM IN THE HOURLY
GRIDS. THE SVR POTENTIAL WILL HINGE ON MORE SHEAR...AND LESSER
AMOUNTS OF INSTABILITY. THE LATEST EXPERIMENTAL HRRR FROM THE SPC
MESOANALYSIS PAGE SHOWS 40-50 KTS OF BULK SHEAR IN THE 0-6 KM
LAYER FROM THE CAPITAL REGION NORTH...AND AND 30-40 KTS TO THE
SOUTHEAST. INSTABILITY VALUES OFF THE 12Z NAM ARE GENERALLY
1000-1500 J/KG WITH SLIGHTLY HIGHER POCKETS OF SBCAPE. MID LEVEL
LAPSE RATES ARE IN THE 6-6.5 C/KM RANGE.
A NEW RUNNING OF THE LOCAL MAGLENTA SEVERE WEATHER INDEX SHOWS A
MINOR SEVERE EVENT WITH THE FOLLOWING VALUES PLUGGED IN:
CAPE=1000 K/KG
MAX SOUNDING WINDS=50 KTS
EHI=1.0
STORM SPEED= 35 KTS
0-3 KM SRH = 100 (M/S)^2
IF THE CAPE IS INCREASED TO 1500 J/KG...WE SHOW A MAJOR EVENT.
THE CONVECTIVE MODE WOULD INDICATE SOME MULTICELLS AND OR ISOLD
SUPERCELLS...POTENTIALLY CONGEALING INTO CLUSTERS AND LINES. THE
SATELLITE TRENDS WILL BE MONITORED CAREFULLY.
OUR LOCAL WRF SHOWS A FEW CLUSTERS DEVELOPING IN THE 0-3 KM
COLUMNAR REF PRODUCT IN THE EARLY TO MID PM...AND CONTINUING OVERNIGHT.
THE EXPERIMENTAL HRRR INDICATES LATE PM/EARLY PM.W
PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL
WITH VALUES OF 1.25-1.75 INCH RANGE...SO SOME HEAVY DOWNPOURS ARE POSSIBLE.
OVERALL..THE SLIGHT RISK FOR OUR AREA LOOKS FINE...AND WE WILL
CONTINUE TO MONITOR THE NEAR TERM TRENDS. MAX TEMPS IN THE M70S TO
M80S LOOK FINE FOR NOW.
CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS
FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE
60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC
LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST
LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO
BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN
PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG
DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS
WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS
ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY.
REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING
TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT.
BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC
COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS
DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS
WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW
MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS.
HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT.
BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME
PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF
LINGERING SKIES MAY ONLY BE PS SAT IN GFS.
TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS
A FEW DEG...OR HOLDING STEADY.
THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI
NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT
NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT.
THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A
COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND
WITH PERIODS OF RAW CHILLY RAIN.
THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO
MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN
ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO
THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL
REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME
TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC
LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A
FALL LIKE MEMORIAL DAY WEEKEND.
WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW
ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON
MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER.
GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20
MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD.
ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS
FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS
SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM
GRT PLAINS TO GRTLKS.
PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE
CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE
HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY
AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND
ABV BY TUESDAY AND WED.
WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE
MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON
AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL
START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM
COUNTY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
SOME LOW CLOUDS ARE AFFECTING MOST OF THE TAF SITE THIS
MORNING...WITH IFR SCATTERED VARIABLE BROKEN AT KALB...SOLID IFR
AT KPSF AND KGFL AND SOLID MVFR AT KPOU. SOME FOG IS OCCURRING AT
KPSF. THE LOW CLOUDS AND FOG SHOULD LIFT BTWN 13-15Z...LEAVING A
MIX OF CLOUDS ABOVE 3000 FEET AGL FOR THE REST OF THE DAY AT ALL
SITES.
THUNDERSTORMS SHOULD DEVELOP AGAIN THIS AFTERNOON AND CONTINUE MUCH
OF TONIGHT...BUT DUE TO THE SCATTERED NATURE...JUST PUTTING VCSH
UNTIL REGIONS OF THUNDERSTORM DEVELOPMENT CAN BE OBSERVED AND
MOVEMENT CAN BE TRACKED LATER TODAY. WHEREVER THUNDERSTORMS
OCCUR...MVFR AND IFR CONDITIONS WILL OCCUR BUT AGAIN...SCATTERED
NATURE TO THUNDERSTORMS PREVENTING ACKNOWLEDGING IN TAFS FOR NOW.
WINDS SHOULD BE SOUTH TO SOUTHWEST AT 10 KT OR LESS TODAY...
DIMINISHING TO LESS THAN 10 KT TONIGHT.
OUTLOOK...
THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL
CONTINUE INTO FRIDAY.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON.
WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING
SOUTHWEST AROUND 10MPH THURSDAY.
&&
.HYDROLOGY...
PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE
WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN
THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN
FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN
BANK RISES ARE LIKELY IN LARGER RIVERS.
3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT
THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY.
DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS...
BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST
THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS
WILL THIS AFTERNOON INTO THURSDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER/WASULA
NEAR TERM...SNYDER/WASULA
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...NAS/WASULA
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
800 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE
SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST
INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG
COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW
PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH
COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE
OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR
THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH
UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TSTMS HAVE ENDED AND ONLY SCT -SHRA REMAIN MAINLY OVER S VT AND
BERKSHIRE COUNTY. SOME ISOLD -SHRA ARE ALONG THE S TIER. FOR THE
NEXT SVRL HOURS MOST OF THIS ACTIVITY WILL DIMINISH AND END.
CLOUDS OVER MUCH OF FCA WILL THIN WITH INCRG SUNSHINE FOR A FEW
HRS.
THE HOOSIC RIVER AND SOME SMALL STREAMS IN SOUTHERN VERMONT HAVE
REACHED BANK FULL AND MAY BRIEFLY EXCEED FLOOD THIS MORNING BEFORE
RECEDING. WARNINGS AND ADVISORIES HAVE BEEN ISSUED TO COVER THESE
SITUATIONS.
AT SFC WMFNT IS N OF FCA. IT WILL MOVE TO ST LAWRENCE VLY TO
MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP
IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL
LLVL MOISTURE/CLOUDS FM TUES CONVECTION
WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT
OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED
TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE
TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF
1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE
FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY.
NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN.
GOING TO HRRR FOR THE LATE AFTN:
POU/ALB/GFL
CAPE 2000/1812/1777
J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2
STORM SPEED 24/18/18
SRH 175/156/106
MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE
WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM
MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN
CAPE AROUND 1000-1200 J/KG.
PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL
WITH VALUES OF 1.50-1.8 INCHES.
SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND
BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER
FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL
NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF
THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED
TIME OF LATER IN THE AFTN AND EVENING.
CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS
FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE
60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC
LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST
LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO
BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN
PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG
DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS
WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS
ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY.
REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING
TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT.
BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC
COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS
DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS
WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW
MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS.
HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT.
BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME
PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF
LINGERING SKIES MAY ONLY BE PS SAT IN GFS.
TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS
A FEW DEG...OR HOLDING STEADY.
THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI
NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT
NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT.
THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A
COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND
WITH PERIODS OF RAW CHILLY RAIN.
THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO
MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN
ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO
THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL
REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME
TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC
LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A
FALL LIKE MEMORIAL DAY WEEKEND.
WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW
ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON
MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER.
GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20
MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD.
ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS
FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS
SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM
GRT PLAINS TO GRTLKS.
PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE
CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE
HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY
AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND
ABV BY TUESDAY AND WED.
WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE
MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON
AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL
START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM
COUNTY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SOME LOW CLOUDS ARE AFFECTING MOST OF THE TAF SITE THIS
MORNING...WITH IFR SCATTERED VARIABLE BROKEN AT KALB...SOLID IFR
AT KPSF AND KGFL AND SOLID MVFR AT KPOU. SOME FOG IS OCCURRING AT
KPSF. THE LOW CLOUDS AND FOG SHOULD LIFT BTWN 13-15Z...LEAVING A
MIX OF CLOUDS ABOVE 3000 FEET AGL FOR THE REST OF THE DAY AT ALL
SITES.
THUNDERSTORMS SHOULD DEVELOP AGAIN THIS AFTERNOON AND CONTINUE MUCH
OF TONIGHT...BUT DUE TO THE SCATTERED NATURE...JUST PUTTING VCSH
UNTIL REGIONS OF THUNDERSTORM DEVELOPMENT CAN BE OBSERVED AND
MOVEMENT CAN BE TRACKED LATER TODAY. WHEREVER THUNDERSTORMS
OCCUR...MVFR AND IFR CONDITIONS WILL OCCUR BUT AGAIN...SCATTERED
NATURE TO THUNDERSTORMS PREVENTING ACKNOWLEDGING IN TAFS FOR NOW.
WINDS SHOULD BE SOUTH TO SOUTHWEST AT 10 KT OR LESS TODAY...
DIMINISHING TO LESS THAN 10 KT TONIGHT.
OUTLOOK...
THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL
CONTINUE INTO FRIDAY.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON.
WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING
SOUTHWEST AROUND 10MPH THURSDAY.
&&
.HYDROLOGY...
PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE
WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN
THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN
FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN
BANK RISES ARE LIKELY IN LARGER RIVERS.
3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT
THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY.
DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS...
BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST
THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS
WILL THIS AFTERNOON INTO THURSDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...SNYDER
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...NAS/WASULA
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
729 AM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. WARM
AND HUMID CONDITIONS CONTINUE INTO THURSDAY AND FRIDAY WITH
SHOWERS AND SCATTERED STRONG THUNDERSTORMS POSSIBLE. COOLER AND
LESS HUMID CONDITIONS ARE EXPECTED FOR THIS HOLIDAY WEEKEND AS
HIGH PRESSURE BUILDS ACROSS THE NORTHEAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
CONVECTION IS FINALLY DYING DOWN AS IT ENTERS INTO ALREADY WORKED
OVER AIR. EXPECT PRECIP TO CONTINUE TO MOVE EASTWARD AND
DISSIPATE. TEMPS ARE SLOW TO REBOUND THIS MORNING...BUT WITH
WINDS SOUTH OF THE PIKE ALREADY SWITCHING TO THE SW...EXPECT TEMPS
TO JUMP LATER THIS MORNING. OTHERWISE BULK OF THE FORECAST REMAINS
ON TRACK AS STRONG TO SEVERE WEATHER IS STILL ANTICIPATED ACROSS
THE WESTERN HALF OF THE REGION.
PREVIOUS DISCUSSION...
CONTINUING TO MONITOR WAVES OF CONVECTION THIS MORNING. LATEST
RUNS OF THE HRRR APPEAR TO HAVE THE BEST HANDLE ON THESE BANDS OF
CONVECTION...ALTHOUGH ITS TIMING WAS SLOW BY A FEW HOURS. LEANED
HEAVILY ON THE 05Z HRRR WITH THE APPROPRIATE TIMING ADJUSTMENT FOR
THE EARLY MORNING FORECAST. SHOWERS AND THUNDERSTORMS ARE
REASONABLY HOLDING TOGETHER IN A HIGH SHEAR/LOW CAPE ENVIRONMENT.
LATER TODAY...EXPECTING THE STALLED BACK-DOOR COLD FRONT TO MOVE
BACK NORTH AS A WARM FRONT. THERE ARE STILL SOME QUESTIONS AS TO
HOW FAST THIS WILL HAPPEN. CURRENTLY THINKING THERE IS NOT ENOUGH
PUSH TO DRIVE IT COMPLETELY THROUGH SOUTHERN NEW ENGLAND. AS
SUCH...MAINTAINED COASTAL SEABREEZE FRONTS ALONG BOTH COASTS.
THIS HAS BIG RAMIFICATIONS FOR TEMPERATURES ALONG THE EAST COAST.
SHOULD THIS FRONT GET ENOUGH PUSH...CURRENT FORECAST TEMPERATURES
ARE LIKELY 5-10 DEGREES TOO LOW ALONG THE IMMEDIATE COASTLINE. AM
MORE CONFIDENT WITH TEMPERATURES FARTHER INLAND. SHOULD THERE BE
MORE SUNSHINE THAT CURRENTLY THINKING...LIKELY TOO LOW FARTHER
INLAND AS WELL.
THINKING THERE WILL BE MORE CLOUDS THAN SUNSHINE TODAY OWING TO
LOTS OF CONVECTIVE DEBRIS FROM THE OVERNIGHT SHOWERS...AS WELL AS
NEW CONVECTIVE CLOUDS AS WE HEAD INTO THIS AFTERNOON.
MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED LATER TODAY. THERE IS
THE POSSIBILITY FOR MORE ISOLATED SEVERE WEATHER. THE GREATEST
RISK SHOULD BE FARTHER WEST OF OUR REGION WHERE THE MORE FAVORABLE
COMBINATION OF INSTABILITY AND SHEAR SHOULD BE. THE BEST ADVICE IS
TO KEEP AN EYE ON THE SKY AND LATER FORECASTS IF YOU WILL BE
OUTDOORS THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...MORE OF THE SAME TONIGHT. WARM FRONT CONTINUES TO PUSH
NORTH AS STRONGER SOUTH TO SOUTHWEST SYNOPTIC FLOW DEVELOPS.
DECENT INSTABILITY PERSISTS THROUGH THE NIGHT. SO THINKING WE WILL
BE SEEING ANOTHER NIGHT OF ISOLATED TO SCATTERED THUNDERSTORMS.
THE GREATEST RISK OF THESE WILL BE ACROSS THE INTERIOR...AWAY FROM
THE STABILIZING INFLUENCE OF THE OCEAN.
THURSDAY...SOUTHERN NEW ENGLAND REMAINS IN THE WARM SECTOR OF A
LOW PRESSURE MOVING FROM THE GREAT LAKES INTO THE SAINT LAWRENCE
RIVER VALLEY. THIS LOW HAS A RATHER AMPLIFIED UPPER SYSTEM...SO
ITS COLD FRONT WILL BE SLOW TO MOVE ACROSS OUR REGION.
EXPECTING MORE ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS.
VERY HUMID AIRMASS IN PLACE AS WELL...WITH PRECIPITABLE WATER
VALUES AROUND 1.7 INCHES. WILL LIKELY SEE SOME HEAVY DOWNPOURS
WITH SOME SHOWERS...ALONG WITH SOME HAIL AND GUSTY WINDS. MAY NOT
QUITE REACH SEVERE THRESHOLDS AS CLOUDS WILL BE MORE PREVALENT...
THUS TEMPERATURES SHOULD BE LOWER THAN WEDNESDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY
* COOLER AND LESS HUMID FOR THE WEEKEND
CONFIDENCE LEVEL/MODEL GUIDANCE...MODERATE CONFIDENCE IN OVERALL
FORECAST. 00Z MODELS CONTINUE TO SLOW DOWN THE ELONGATED TROUGH
MOVING ACROSS THE EASTERN HALF OF THE CONUS. THERE IS STILL SOME
TIMING DIFFERENCES ON WHEN THE SYSTEM WILL PUSH THROUGH THE
NORTHEAST. REGARDLESS APPEARS THAT ELONGATED TROUGH WILL MOVE INTO
NEW ENGLAND EVENTUALLY BECOMING A CUTOFF LOW BY THE WEEKEND. THIS
LOW WILL EVENTUALLY MOVE INTO THE MARITIMES BY THE BEGINNING OF
THE WORK WEEK AS HIGH PRESSURE MOVES IN. HAVE HIGH CONFIDENCE THAT
PRECIP WILL OCCUR ON FRIDAY AND COOLER TEMPS WILL DOMINATE THE
REGION FOR THE WEEKEND. LOW CONFIDENCE IN FORECAST AFTER TUES.
DETAILS...
THURSDAY NIGHT INTO FRIDAY...
UPPER LEVEL TROUGH WILL PUSH THROUGH THE EASTERN GREAT LAKES
REGION EVENTUALLY PUSHING A COLD FRONT THROUGH SOUTHERN NEW
ENGLAND. MODELS CONTINUE TO SLOW THE TIMING OF THE FRONT DOWN...SO
BELIEVE THAT IT MOVE THROUGH SOMETIME ON FRIDAY. BECAUSE OF THE
MODEL DIFFERENCE HAVE LOW CONFIDENCE IN TIMING.
REGARDLESS...BELIEVE THAT SHOWERS AND THUNDERSTORMS WILL MOVE
THROUGH WITH TEMPS NEAR AVG. CANNOT RULE OUT A FEW STRONG
THUNDERSTORMS ESPECIALLY ACROSS REGIONS SOUTH OF THE I-84
CORRIDOR. MODELS INDICATE SOME INSTABILITY WITH ABOUT 25KTS OF
SHEAR. PWAT VALUES OF OVER 1.5 INCHES LEADS FORECASTER TO BELIEVE
THAT HEAVY DOWNPOURS IS THE MAIN THREAT...BUT WITH FALLING HEIGHTS
AS COLD FRONT APPROACHES...SMALL HAIL AND GUSTY WINDS IS NOT OUT
OF THE QUESTION. ANY CHANCE FOR STRONG STORMS TO DEVELOP WILL
DIMINISH AFTER SUNSET AS DIURNAL HEATING IS LOST.
WEEKEND...TRICKY FORECAST IS PLAYING OUT FOR THE WEEKEND. MODELS
HAVE INDICATED THAT THE ELONGATED TROUGH WILL CUT OFF OVER THE MID
ATLANTIC AND SLOWLY ROTATE OVER NEW ENGLAND FOR THE WEEKEND. THIS
WILL ALLOW FOR MUCH COOLER AIR...WELL BELOW AVG AND EVEN HAS
SLOWED DOWN THE TIMING OF PRECIP. BELIEVE THAT PRECIP MAY LINGER
INTO SAT...BUT HAVE LOW CONFIDENCE THAT PRECIP WILL OCCUR ON
SUNDAY. FOR NOW HAVE CONTINUED WITH THE SLOW DOWN TREND IN THE
FORECAST. EXPECT HIGHS REACHING INTO THE MID TO UPPER 60S WITH
LOWS DROPPING INTO THE MID TO UPPER 30S. IF SKIES CLEAR OUT AS
THIS COLD POOL SITS OVER US...THERE IS A POSSIBILITY THAT
FROST/FREEZE HEADLINES MAY BE NEEDED AS THE ENTIRE REGION IS
OFFICIALLY IN THE GROWING SEASON.
MONDAY AND BEYOND...SURFACE HIGH PRESSURE WILL BE IN CONTROL FOR
THE FIRST HALF OF NEXT WEEK. THIS WILL HELP TEMPS REACH SEASONAL
CONDITIONS. APPEARS THAT THERE IS LIMITED MOISTURE KEEPING THE
FORECAST DRY...HOWEVER CANNOT RULE OUT A SPOT SHOWER OR TWO...ESP
IF SEA BREEZES DEVELOPS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE IN TIMING AND AREAL COVERAGE OF
STRATUS AND FOG THROUGH THIS MORNING.
TODAY...EXPECT MVFR-LIFR CONDITIONS TO GRADUALLY IMPROVE TO VFR
14-16Z AS SW WINDS DEVELOP. IFR MAY PERSIST MOST OF THE DAY AT
KACK. ISOLATED TO SCATTERED CONVECTION BECOMING MORE WIDESPREAD
THIS AFTERNOON...ESPECIALLY WEST OF KMHT-KORH-KIJD.
TONIGHT...MODERATE CONFIDENCE IN TRENDS. EXPECT VARIABLE
CONDITIONS DEPENDING UPON SHOWER AND FOG DEVELOPMENT. BETTER SHOT
FOR IFR VSBYS IN FOG ALONG S COAST ON S-SW WINDS AND MILD TEMPS
MAINLY AFTER MIDNIGHT. SCT SHOWERS/TSTMS ACROSS MOST OF THE REGION
THOUGH BEST SHOT ACROSS CENTRAL AND WESTERN AREAS...WITH MVFR-IFR
CIGS/VSBYS. MAY SEE LOCAL HEAVY DOWNPOURS. LOW CONFIDENCE ON
TIMING AND PLACEMENT.
THURSDAY...MODERATE CONFIDENCE IN TRENDS. VERY UNSETTLED PATTERN
AHEAD OF APPROACHING COLD FRONT. VARIABLE CONDITIONS BETWEEN VFR
AND MVFR/IFR IN SHRA/TSRA/PATCHY FOG. COLD FRONT CROSSES THE
REGION THU NIGHT...SO WILL SEE IMPROVING CONDITIONS ACROSS WESTERN
AREAS AFTER MIDNIGHT THU NIGHT...THEN INTO CENTRAL SECTIONS AFTER
06Z-07Z. MAY SEE SW WIND GUSTING UP TO 20-25 KT DURING THE DAY AS
WELL. WINDS SHIFT TO W-NW ACROSS CENTRAL AND WESTERN AREAS AFTER
MIDNIGHT.
KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS...LOWER CONFIDENCE
IN TIMING OF LOWER CONDITIONS AND CONVECTION THIS AFTERNOON.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING
OF CONVECTION THIS AFTERNOON. COULD SEE BRIEF IFR IN A BAND OF
TSRA.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT INTO FRIDAY...LOW CONFIDENCE. MODERATE CONFIDENCE
ON SEA BREEZE DEVELOPMENTS. VERY UNSETTLED PATTERN WITH
VARIABILITY BETWEEN VFR CONDITIONS AND MVFR/IFR CONDITIONS IN
SHRA/TSRA/FOG. IMPROVING CONDITIONS LATE FRIDAY NIGHT INTO
SATURDAY MORNING.
SATURDAY-SUNDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TONIGHT.
WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
THROUGH TODAY. INCREASING SW FLOW WILL RESULT IN SEAS BUILDING
OVER THE SOUTHERN COASTAL WATERS. SMALL CRAFT ADVISORY ISSUED FOR
LATER TODAY INTO THURSDAY FOR COASTAL WATERS WHERE CONFIDENCE IS
HIGHEST. WINDS SHOULD CONTINUE TO INCREASE TONIGHT INTO THURSDAY
AS A LOW PRESSURE MOVES INTO THE GREAT LAKES. AS SUCH COULD SEE
SMALL CRAFT ADVISORY EXPAND INTO MORE OF THE COASTAL WATERS AROUND
CAPE COD DUE TO 25 KT WIND GUSTS. CONFIDENCE IS NOT YET HIGH
ENOUGH TO ISSUE ADVISORIES FOR THOSE WATERS AT THIS TIME.
EXPECT LOW VSBYS IN HEAVY SHOWERS AND PATCHY FOG AT TIMES.
ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE AS WELL...ESPECIALLY
NEAR SHORE.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
FRIDAY...MODERATE TO HIGH CONFIDENCE. COLD FRONT WILL BE SLOW TO
CLEAR THE WATERS...SO EXPECT SW WINDS IN PLACE FOR A PORTION OF
THE DAY BEFORE SHIFTING TO W-NW ACROSS THE EASTERN WATERS.
THE WEEKEND...MODERATE CONFIDENCE. SEAS WILL REMAIN ABOVE SCA FOR
MOST OF THE WEEKEND ESP FOR THE OUTER WATERS. GUSTY NW BEHIND THE
FRONT WILL BRING GUSTS CLOSE TO GALE FORCE SAT INTO SAT NIGHT.
EXPECT BOTH SEAS AND WIND TO SLOWLY SUBSIDE THROUGHOUT THE DAY
ON SUNDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THURSDAY FOR
ANZ255-256.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM EDT
THURSDAY FOR ANZ235-254.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT
THURSDAY FOR ANZ237.
&&
$$
SYNOPSIS...BELK/DUNTEN
NEAR TERM...BELK/DUNTEN
SHORT TERM...BELK
LONG TERM...DUNTEN
AVIATION...BELK/DUNTEN
MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
627 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE
SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST
INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG
COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW
PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH
COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE
OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR
THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH
UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TSTMS HAVE ENDED AND ONLY SCT -SHRA REMAIN MAINLY OVER S VT AND
BERKSHIRE COUNTY. SOME ISOLD -SHRA ARE ALONG THE S TIER. FOR THE
NEXT SVRL HOURS MOST OF THIS ACTIVITY WILL DIMINISH AND END.
CLOUDS OVER MUCH OF FCA WILL THIN WITH INCRG SUNSHINE FOR A FEW
HRS.
THE HOOSIC RIVER AND SOME SMALL STREAMS IN SOUTHERN VERMONT HAVE
REACHED BANKFUL AND MAY BRIEFLY EXCEED FLOOD THIS MORNING BEFORE
RECEDING. WARNINGS AND ADVISORIES HAVE BEEN ISSUED TO COVER THESE
SITUATIONS.
AT SFC WMFNT IS N OF FCA. IT WILL MOVE TO ST LAWRENCE VLY TO
MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP
IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL
LLVL MOISTURE/CLOUDS FM TUES CONVECTION
WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT
OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED
TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE
TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF
1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE
FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY.
NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN.
GOING TO HRRR FOR THE LATE AFTN:
POU/ALB/GFL
CAPE 2000/1812/1777
J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2
STORM SPEED 24/18/18
SRH 175/156/106
MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE
WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM
MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN
CAPE AROUND 1000-1200 J/KG.
PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL
WITH VALUES OF 1.50-1.8 INCHES.
SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND
BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER
FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL
NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF
THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED
TIME OF LATER IN THE AFTN AND EVENING.
CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS
FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE
60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC
LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST
LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO
BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN
PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG
DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS
WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS
ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY.
REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING
TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT.
BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC
COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS
DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS
WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW
MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS.
HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT.
BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME
PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF
LINGERING SKIES MAY ONLY BE PS SAT IN GFS.
TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS
A FEW DEG...OR HOLDING STEADY.
THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI
NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT
NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT.
THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A
COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND
WITH PERIODS OF RAW CHILLY RAIN.
THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO
MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN
ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO
THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL
REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME
TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC
LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A
FALL LIKE MEMORIAL DAY WEEKEND.
WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW
ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON
MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER.
GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20
MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD.
ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS
FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS
SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM
GRT PLAINS TO GRTLKS.
PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE
CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE
HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY
AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND
ABV BY TUESDAY AND WED.
WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE
MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON
AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL
START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM
COUNTY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD
CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT
07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR
CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED
THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN
KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF
THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN.
ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF
MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW
1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD
SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000
FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES
THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND
TRENDS CHANGE.
VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z
UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING.
MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE
LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE
THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE
TOMORROW AFTERNOON AND EVENING.
WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE
AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO
SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD
BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING.
OUTLOOK...
WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN.
WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF
AND KPOU CHC -SHRA/-TSRA.
THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL
CONTINUE INTO FRIDAY.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON.
WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING
SOUTHWEST AROUND 10MPH THURSDAY.
&&
.HYDROLOGY...
PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE
WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN
THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN
FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN
BANK RISES ARE LIKELY IN LARGER RIVERS.
3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT
THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY.
DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS...
BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST
THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS
WILL THIS AFTERNOON INTO THURSDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...SNYDER
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...NAS
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1035 AM EDT WED MAY 22 2013
.DISCUSSION...
LARGE RIDGE AXIS OVER THE W ATLC WILL COMBINE WITH A WEAK LOW LVL
TROF CENTERED OFF THE FL BIG BEND TO GENERATE AN ACTIVE WX PATTERN
ACRS CENTRAL FL. DEEP BUT LIGHT SRLY FLOW WILL DRAW DEEP MOISTURE UP
FROM THE S...PWAT VALUES INCREASE FROM 1.5" AT KTBW/KXMR TO 1.8" AT
KMFL. RAP ANALYSIS SHOWING H100-H70 MEAN RH VALUES AOA 70PCT ACRS
THE ENTIRE PENINSULA. AIRMASS IS NOT EXPLOSIVELY UNSTABLE AS H50
TEMPS ARE HOLDING ARND -9C WITH MID LVL LAPSE RATES BTWN
5.5-6.0C/KM. HOWEVER...POSITION OF THE TROF AXIS WILL PLACE THE EAST
CENTRAL PENINSULA ON ITS ASCENDING SIDE.
ACTIVITY ALREADY DVLPG AREAWIDE WILL CONTINUE THRU THE DAY...ESP
ALNG THE EAST COAST SEA BREEZE AS IT DVLPS AND DRIFTS INLAND. THE
OFF HOUR MAV GUIDANCE CONTINUES TO INDICATE POPS BTWN 60-70PCT...
CAN SEE NO REASON TO DISCOUNT THEM AS MOISTURE IS ALMOST UNIFORMLY
DISTRIBUTED THRU THE COLUMN AND THERE ARE NO SIGNIFICANT INHIBITORS
TO UPWARD VERTICAL MOTION. MAX TEMPS WITHIN A FEW DEGS OF CLIMO
AVG...M/U80S AREAWIDE.
MINOR CHANGES TO PRECIP DISTRIBUTION AND TIMING TO FOCUS HIGHER POPS
OVER INTERIOR AND N CSTL ZONES.
&&
.AVIATION...
THRU 22/22Z...PREVAILING VFR ALL SITES...NMRS SHRAS/SCT TSRAS DVLPG
AND MVG N/NE ARND 10KTS WILL PRODUCE TEMPO IFR VSBYS/CIGS. BTWN
22/22Z-23/01Z...CONVECTION DIMINISHING BCMG SCT MVFR SHRAS W OF
KTIX-KOBE...CONTG THRU 23/03Z. AFT 23/03Z...VFR ALL SITES WITH LCL
MVFR VSBYS IN BR.
&&
.MARINE...
NO HIGHLIGHTS...NO SIG CHANGES. ATLC RIDGE AXIS OVER THE W ATLC WILL
GENERATE A LIGHT TO GENTLE S/SE BREEZE ACRS THE AREA...SEAS 2-3FT
NEARSHORE AND 3-4FT OFFSHORE. NMRS SHRAS/ISOLD TSRAS OVER THE GULF
STREAM DUE TO A MOIST AND UNSTABLE AIRMASS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...KELLY
LONG TERM/IMPACT WX...BRAGAW
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
937 AM EDT WED MAY 22 2013
.UPDATE 2...TROUGH OF LOW PRESSURE OVER THE FLORIDA PENINSULA
WILL CONTINUE TO MOVE SLOWLY EAST INTO THE WESTERN ATLANTIC WATERS
TODAY. THIS WILL ALLOW FOR A LITTLE BIT OF DRIER AIR TO WORK INTO
THE AREA FROM THE GULF OF MEXICO. HOWEVER...THE EAST AND WEST
COAST SEA BREEZES WILL DEVELOP TODAY AND PUSH INLAND. THE WEST
COAST SEA BREEZE WILL PUSH ACROSS THE AREA TODAY WITH THE EAST
COAST SEA BREEZE REMAINING NEAR THE EAST COAST METRO AREAS DUE TO
THE SOUTH TO SOUTHWEST STEERING FLOW OVER THE AREA.
SO THE SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS THIS
MORNING SHOULD DISSIPATE BY NOON TIME WITH SHOWERS AND
THUNDERSTORMS DEVELOPING OVER THE LAND AREAS. SO WILL KEEP THE
SCATTERED TO NUMEROUS POPS OVER SOUTH FLORIDA FOR THIS AFTERNOON.
THERE COULD ALSO BE A FEW STRONG STORMS OVER THE INTERIOR AND EAST
COAST METRO AREAS THIS AFTERNOON INTO EARLY THIS EVENING. THE
PRIMARY IMPACTS FROM THE STRONG STORMS WILL BE GUSTY WINDS...HEAVY
RAINFALL...AND SMALL HAIL. SO WILL CONTINUE TO MENTION THIS IN THE
MORNING HWO PACKAGE.
REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES
ARE PLANNED.
&&
.UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 719 AM EDT WED MAY 22 2013/
AVIATION...SCATTERED SHOWERS WILL CONTINUE THIS MORNING ACROSS THE EASTERN
PORTIONS OF THE PENINSULA WITH TERMINALS KMIA...KOPF AND KTMB
POSSIBLY HAVING BRIEF PERIODS OF MVFR CEILINGS. THERE IS A LINGERING
MID TO UPPER LEVEL TROUGH AND AVAILABLE TROPICAL MOISTURE THAT IS
EXPECTED TO ENHANCE CHANCES OF CONVECTION TODAY WITH ALL TERMINALS
ASSIGNED VCTS AT 15Z EXCEPT FOR TERMINAL KAPF ASSIGNED AT 16Z. FOR
ALL TERMINALS BRIEF PERIODS OF IFR CONDITIONS MAY BE POSSIBLE WITH THE
STRONGER THUNDERSTORMS BY THE EARLY AFTERNOON.
&&
PREV DISCUSSION... /ISSUED 523 AM EDT WED MAY 22 2013/
UPDATE...SHOWERS HAVE RECENTLY INCREASED OVER THE ATLANTIC WITH
MOVEMENT ONSHORE THE COAST. SOME ARE BECOMING HEAVY WITH EVEN A
THUNDERSTORM IN FAR SOUTH MIAMI-DADE WITH A FEW LIGHTNING STRIKES
DETECTED. GIVEN THE RADAR TRENDS AND HRRR DEPICTION, HAVE INCREASED
WEATHER TO NUMEROUS FOR ALL OF THE EAST COAST AND INTERIOR THROUGH
THIS AFTERNOON. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 356 AM EDT WED MAY 22 2013/
DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL
GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE
GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY
TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE
FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST
PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH
LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT
AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM
BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING
THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN
THE HAZARDOUS WEATHER OUTLOOK.
THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS
AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT
OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND
WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT
BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED
AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND
ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO
FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH
BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT
AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN
OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG
HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT
LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO
THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL
NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE
SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND.
FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO
SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND
THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE
OFFING.
MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER
LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN
NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING
INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING
SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND.
FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE
CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 72 87 73 / 60 40 30 20
FORT LAUDERDALE 86 74 88 76 / 60 40 30 20
MIAMI 87 74 89 76 / 60 40 30 20
NAPLES 86 71 86 72 / 30 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS MIAMI FL
719 AM EDT WED MAY 22 2013
.AVIATION...SCATTERED SHOWERS WILL CONTINUE THIS MORNING ACROSS THE EASTERN
PORTIONS OF THE PENINSULA WITH TERMINALS KMIA...KOPF AND KTMB
POSSIBLY HAVING BRIEF PERIODS OF MVFR CEILINGS. THERE IS A LINGERING
MID TO UPPER LEVEL TROUGH AND AVAILABLE TROPICAL MOISTURE THAT IS
EXPECTED TO ENHANCE CHANCES OF CONVECTION TODAY WITH ALL TERMINALS
ASSIGNED VCTS AT 15Z EXCEPT FOR TERMINAL KAPF ASSIGNED AT 16Z. FOR
ALL TERMINALS BRIEF PERIODS OF IFR CONDITIONS MAY BE POSSIBLE WITH THE
STRONGER THUNDERSTORMS BY THE EARLY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 523 AM EDT WED MAY 22 2013/
UPDATE...SHOWERS HAVE RECENTLY INCREASED OVER THE ATLANTIC WITH
MOVEMENT ONSHORE THE COAST. SOME ARE BECOMING HEAVY WITH EVEN A
THUNDERSTORM IN FAR SOUTH MIAMI-DADE WITH A FEW LIGHTNING STRIKES
DETECTED. GIVEN THE RADAR TRENDS AND HRRR DEPICTION, HAVE INCREASED
WEATHER TO NUMEROUS FOR ALL OF THE EAST COAST AND INTERIOR THROUGH
THIS AFTERNOON. /GREGORIA
PREV DISCUSSION... /ISSUED 356 AM EDT WED MAY 22 2013/
DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL
GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE
GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY
TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE
FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST
PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH
LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT
AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM
BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING
THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN
THE HAZARDOUS WEATHER OUTLOOK.
THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS
AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT
OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND
WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT
BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED
AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND
ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO
FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH
BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT
AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN
OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG
HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT
LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO
THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL
NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE
SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND.
FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO
SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND
THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE
OFFING.
MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER
LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN
NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING
INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING
SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND.
FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE
CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 72 87 73 / 60 30 30 20
FORT LAUDERDALE 85 74 88 76 / 60 20 30 20
MIAMI 87 74 89 76 / 60 20 30 20
NAPLES 85 71 86 72 / 40 20 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1009 AM EDT WED MAY 22 2013
.SYNOPSIS...
A WARM FRONT WILL SLOWLY PROGRESS NORTH ACROSS THE REGION TODAY
AND TONIGHT. LOW PRESSURE WILL LIFT TO OUR WEST ON THURSDAY THEN
GRADUALLY PUSH A FRONT ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...12Z KCAR RAOB SHOWS DEEP LAYER MOISTURE PROFILE
THIS MORNING. VISIBLE IMAGERY ALSO SHOWS EXTENSIVE LOW CLOUD
ACROSS THE FA. EXPECT CLOUDY SKIES ACROSS THE REGION TODAY.
CURRENT RADAR IMAGERY DOES SHOW THE LAST OF THE STEADIER SHOWERS
EXITING THE INTERNATIONAL BORDER INTO NEW BRUNSWICK. MADE
ADJUSTMENTS TO POPS FOR TODAY UTILIZING THE RUC13 WHICH WAS DOING A
FAIRLY GOOD JOB AS OF EARLY THIS MORNING. THUS...ONLY EXPECTING
SCATTERED SHOWERS THE BALANCE OF THE DAY. OTHERWISE...ADJUSTED
CURRENT HOURLY TEMPS AND INTERPOLATED TO EXPECTED MAX TEMPS.
A WARM FRONT WILL LIFT NORTH ACROSS THE AREA TONIGHT AS THE LOW
FROM THE GREAT LAKES TRACKS TOWARD WESTERN NEW ENGLAND. SOME
SHOWERS WILL OCCUR ALONG THE FRONT MAINLY ACROSS THE FAR NORTH. AN
EMBEDDED RUMBLE OF THUNDER CAN`T BE RULED OUT. HUMID AIR WILL
LIKELY RESULT IN SOME FOG IN MANY AREAS WEDNESDAY NIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AN ACTIVE AND UNSETTLED PATTERN WILL CONTINUE TO UNFOLD...
LOW PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY LIFT NORTH EARLY
THURSDAY WITH THE AREA BREAKING INTO A WARMER AND MORE HUMID AIR
MASS. NOT EXPECTING MUCH IN THE WAY OF PRECIP IN THE MORNING
HOWEVER IN THE AFTERNOON EXPECT SHOWERS AND THUNDERSTORMS TO
DEVELOP OVER NW PORTIONS OF THE CWA ALONG AND AHEAD OF THE FRONT
AS IT BEGINS TO COLLAPSE BACK TO THE SOUTH AND EAST. MODELS DEPICT
CAPE VALUES OVER NW AREAS GENERALLY AROUND 500 TO 1000 J/KG BUT THERE
IS CONCERN AS SHEAR VALUES LOOK TO BE QUITE STRONG, IN EXCESS OF
40 KNOTS FROM 0-6 KM, WHICH COULD RESULT IN ORGANIZED STRONGER
STORMS DEVELOPING. PWAT VALUES NEAR 1.50 INCHES ALONG A FAIRLY
DEEP WARM CLOUD LAYER AND SLOW STORM MOTION VECTORS SUGGEST HEAVY
RAINFALL WILL BE THE BIGGEST THREAT BUT STRONG WINDS WILL ALSO BE POSSIBLE.
HAVE ADDED ENHANCED WORDING MENTIONING HEAVY RAINFALL IN THE GRIDS
WITH AGAIN, THE BIGGEST CONCERN LOOKING TO BE OVER ROUGHLY THE
NORTHWESTERN THIRD OF THE CWA. SHOWERS/STORMS WILL CONTINUE TO
SHIFT SOUTH AND EAST WITH THE FRONT THURSDAY NIGHT WHILE GENERALLY
WEAKENING WITH TIME. GUIDANCE CONTINUES TO DEPICT THIS FRONT
GETTING HUNG UP AS IT NEARS THE COAST HEADING INTO FRIDAY. THIS
WILL KEEP PERIODS OF RAIN AND SHOWERS GOING RIGHT THROUGH FRIDAY
WITH THE HEAVIEST AND STEADIEST PRECIPITATION SHIFTING TO SOUTHERN
AND EASTERN AREAS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE GFS AND ECMWF HAVE COME INTO LINE BOTH DEPICTING LOW PRESSURE
DEVELOPING ALONG THE STALLED FRONT AND PUSHING NORTH FRIDAY NIGHT
INTO SATURDAY. THIS WILL RESULT IN CONTINUING RAINFALL THROUGH
SATURDAY WITH ADDITIONAL AMOUNTS OF A HALF INCH TO AN INCH
POSSIBLE BY LATE SATURDAY. WITH THE LOW LOOKING TO TRACK EAST OF
THE AREA THIS WILL KEEP THE AREA ON THE COOL SIDE OF THE SYSTEM
WITH NORTHERLY WINDS AND TEMPERATURES STRUGGLING TO MAKE IT OUT OF
THE UPPER 40S AND LOW 50S FOR SATURDAY. THE PICTURE BECOMES EVEN MORE
COMPLEX FOR SATURDAY NIGHT AS COLD AIR CONTINUES TO BE DRAWN
SOUTH. THIS COULD POTENTIALLY RESULT IN RAIN CHANGING TO SOME WET
SNOW OVER HIGHER ELEVATIONS SATURDAY BEFORE PRECIPITATION WINDS
DOWN TO SHOWERS HEADING INTO SUNDAY. TEMPERATURES REMAIN VERY COOL
FOR SUNDAY...ONLY REACHING THE LOW TO MID 50S AT BEST.
EXPECT SLOW IMPROVEMENT HEADING INTO EARLY NEXT WEEK. THE
LINGERING UPPER TROUGH WILL RESULT IN PERSISTING CLOUDS, COOL
TEMPERATURES, AND THE CHANCE OF SHOWERS MONDAY WITH WARMER DRIER
WEATHER EXPECTED BY TUESDAY.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: IFR CONDITIONS ARE EXPECTED IN LOW CLOUDS AND AREAS OF
FOG TODAY AND TONIGHT ALTHOUGH CONDITIONS MAY BRIEFLY IMPROVE TO
MVFR AT TIMES ACROSS THE NORTH DURING THE MIDDAY TODAY.
SHORT TERM:
EXPECT MVFR/IFR PERSISTING THURSDAY IN THE SOUTH DUE TO MARINE
FOG AND STRATUS. NORTHERN SITES SHOULD SEE SOME BRIEF IMPROVEMENT
DURING THE DAY BEFORE SHOWERS AND STORMS BRING A RETURN TO MVFR
AND EVENTUALLY IFR BY LATE DAY. EXPECT PREDOMINATELY MVFR AND IFR
CONDITIONS REGION WIDE THURSDAY NIGHT THROUGH SATURDAY DUE TO
CONTINUING PERIODS OF RAIN AND SHOWERS. SOME IMPROVEMENT WILL BE
POSSIBLE SUNDAY AS STEADIER PRECIPITATION WINDS DOWN.
&&
.MARINE...
NEAR TERM: WINDS AND SEAS WILL BE BELOW SCA TODAY AND TONIGHT.
HUMID AIR MOVING IN OVER THE COLDER WATERS WILL LIKELY RESULT IN
AREAS OF FOG THROUGH TONIGHT.
SHORT TERM:
WINDS/SEAS BUILD THURSDAY WITH SCA CONDITIONS EXPECTED BY THE
AFTERNOON CONTINUING THROUGH FRIDAY MORNING. ALSO EXPECT AREAS OF
FOG DURING THIS PERIOD REDUCING VISIBILITIES ALONG WITH PERIODS OF RAIN
AND SHOWERS. WINDS/SEAS MAY BRIEFLY DIMINISH LATE FRIDAY BEFORE
INCREASING ONCE AGAIN SATURDAY AS LOW PRESSURE MOVES NORTH.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON THURSDAY TO NOON EDT FRIDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...BLOOMER/DUDA
SHORT TERM...FITZSIMMONS
LONG TERM...FITZSIMMONS
AVIATION...BLOOMER/DUDA/FITZSIMMONS
MARINE...BLOOMER/DUDA/FITZSIMMONS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
656 AM EDT WED MAY 22 2013
.SYNOPSIS...
A WARM FRONT WILL REMAIN STALLED ACROSS NEW HAMPSHIRE AND MAINE
TODAY...LIFTING NORTH OF THE REGION TONIGHT. A COLD FRONT WILL
SLOWLY APPROACH FROM THE NORTHWEST THURSDAY PUSH OFFSHORE FRIDAY.
LOW PRESSURE WILL DEVELOP ALONG THE FRONT SOUTH OF NEW ENGLAND
FRIDAY NIGHT AND STRENGTHEN IN THE GULF OF MAINE ON SATURDAY,
MOVING INTO THE CANADIAN MARITIMES ON SUNDAY, WITH COOLER THAN
NORMAL TEMPERATURES EXPECTED FRIDAY THROUGH SUNDAY. ON MEMORIAL
DAY AND TUESDAY HIGH PRESSURE WILL NUDGE THE LOW NORTHWARD WITH
SEASONABLY WARM TEMPERATURES RETURNING TO NORTHERN NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
NOT MUCH TO CHANGE FOR THIS UPDATE AS POPS ARE ON TRACK. AREA OF
RAIN NOW MOVING INTO EASTERN MAINE AND OFFSHORE. HRRR HAS HAD A
GOOD HANDLE ON THE EVOLUTION OF THIS RAIN EVENT. WE SHOULD HAVE A
BREAK THROUGH THE MORNING BEFORE RAIN RETURNS THIS AFTERNOON.
&&
PREVIOUS DISCUSSION...
LIGHT TO MODERATE RAIN IS NOW MOVING OVER NORTHERN NEW ENGLAND
WITH A RAIN FREE AREA IMMEDIATELY BEHIND IT. FARTHER SOUTH
CONVECTION IS HEAVIER AND STILL MOVING ACROSS PORTSMOUTH WITH
MORE TO THE SOUTH AND WEST. WHEN THE RAIN DOES SUBSIDE PATCHY
DENSE FOG MAY FORM LATER THIS MORNING. MOST THUNDER IS TO OUR
SOUTH HOWEVER HAVE KEPT ISOLATED STRIKES IN THE FORECAST THIS
MORNING. A WARM FRONT IS THE FOCUS OF THE HEAVIER PRECIPITATION
AND STRETCHES THROUGH SOUTHERN NY STATE AND OVER LONG ISLAND
SOUND.
MOST OF THE PRECIPITATION WITH THIS BATCH WILL EXIT BY LATE
MORNING. WE WILL ONLY SEE A FEW HOURS MOSTLY FREE OF PRECIPITATION
AS THE WARM FRONT LIFTS NORTH AND LOW PRESSURE OVER THE GREAT
LAKES MOVES NORTHEAST ALONG IT. IN ADDITION DIURNAL HEATING AND
MUCAPES AOA 1000 J/KG THIS AFTERNOON WILL TRIGGER THUNDERSTORMS.
THAT SAID...SEVERE WEATHER IS NOT EXPECTED.
TEMPERATURES TODAY WILL DEPEND ON THE EASTWARD PROGRESSION OF THE
WARM FRONT. READINGS WILL RANGE FROM THE UPPER 50S NEAR JACKMAN AND
WATERVILLE TO 70S OVER MUCH OF NH AND FAR WESTERN MAINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
RAIN CONTINUES TONIGHT INTO THE OVERNIGHT HOURS. THE WARM FRONT
WILL LIFT INTO CANADA BY TOMORROW AFTERNOON PLACING THE ENTIRETY
OF NH AND WESTERN MAINE IN THE WARM SECTOR. A NNE TO SSW ORIENTED
COLD FRONT WILL ARRIVE FROM THE WEST LATE IN THE DAY THURSDAY
HELPING TO GENERATE MODERATE RAIN AND ADDITIONAL THUNDERSTORMS.
AFTER WARM OVERNIGHT LOWS...ALMOST THE ENTIRE REGION SHOULD WARM
INTO THE 70S THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE SURFACE COLD FRONT APPROACHES FROM THE WEST THURSDAY NIGHT BUT
WILL BE SLOWED BY A STRENGTHENING SURFACE LOW FORECAST TO RIDE
NORTH UP THE ATLANTIC SEABOARD THURSDAY NIGHT INTO FRIDAY AND
SATURDAY. EXPECTEDLY, THE FORECAST MODELS ARE BICKERING ABOUT THE
STRENGTH OF THIS LOW, WHICH WILL ULTIMATELY DETERMINE HOW RAPIDLY
THE WET WEATHER WILL EXIT EASTERN NEW ENGLAND. THE GFS CONTINUES
TO BE BY FAR THE MOST AGGRESSIVE WITH THIS LOW -- CLOSING OFF A
1001 HPA LOW IN THE BAY OF FUNDY SATURDAY NIGHT. WPC HAS CONTINUED
TO FAVOR THE CONSISTENT AND WEAKER ECMWF SOLUTION, AND WE`VE
FOLLOWED THAT THINKING AS WELL HERE. THIS TRANSLATES TO DRYING OUT
ON SATURDAY INTO SUNDAY, WITH DRY WEATHER CONTINUING INTO EARLY
NEXT WEEK.
AGREEMENT DOES, HOWEVER, COME IN THE UNSEASONABLY COOL UPPER
LEVEL TROUGH OVER THE NORTHEASTERN STATES THROUGH ABOUT SUNDAY
BEFORE FILLING AND MOVING OFFSHORE EARLY NEXT WEEK. MAX
TEMPERATURES FOR FRIDAY AND SATURDAY WILL RUN SOME 10-15F BELOW
NORMAL FOR LATE MAY -- MAKING IT FEEL MORE LIKE PATRIOT`S DAY THAN
MEMORIAL DAY WEEKEND. EVENTUALLY BY THE BEGINNING OF NEXT WEEK A
RETURN TO MORE SEASONABLY WARM TEMPERATURES WILL RETURN.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...LIFR/IFR CONDITIONS TODAY IN FOG/DRIZZLE/SHOWERS/
STRATUS. SOME IMPROVEMENT TO MVFR IN BETWEEN PERIODS OF RAIN.
DETERIORATING CONDITIONS EXPECTED AGAIN TONIGHT.
LONG TERM...MVFR/IFR CONDITIONS THURSDAY NIGHT WILL PERSIST
THROUGH FRIDAY AND GRADUALLY GIVE WAY TO VFR CLEAR CONDITIONS BY
SUNDAY.
&&
.MARINE...
SHORT TERM...A SMALL CRAFT HAS BEEN ISSUED BEGINNING THURSDAY AT
NOON AND LASTING THROUGH FRIDAY. OTHERWISE FOG...DRIZZLE...AND
SHOWERS ARE EXPECTED TO SIGNIFICANTLY REDUCE VISIBILITIES.
LONG TERM...WITH THE FRONT/SURFACE LOW IN THE GULF OF MAINE INTO
THE WEEKEND, EXPECT SMALL CRAFT ADVISORY CONDITIONS IN THE COASTAL
WATERS TO EXTEND AT LEAST INTO FRIDAY AND SATURDAY.
&&
.FIRE WEATHER...
NO ISSUES ANTICIPATED THE REMAINDER OF THIS WEEK DUE TO WET
CONDITIONS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON THURSDAY TO NOON EDT FRIDAY FOR
ANZ150>154.
&&
$$
SHORT TERM...HANES
LONG TERM...STJEAN
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1005 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE PERSISTING OVER THE ATLANTIC WITH WARM AND HUMID
CONDITIONS UNTIL A COLD FRONT THURSDAY NIGHT. AN UPPER TROUGH
WILL LINGER OVER THE AREA FRIDAY WITH HIGH PRESSURE BUILDING
THROUGH SATURDAY. A FRONTAL BOUNDARY STALLS OUT ACROSS THE MID-
ATLANTIC SUNDAY NIGHT THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE BOTH AT THE UPPER-LEVELS AND THE SURFACE WILL REMAIN
OVER THE ATLANTIC OCEAN THROUGH TONIGHT. AN UPPER-LEVEL TROUGH WILL
SLOWLY SHIFT FROM THE CENTRAL CONUS INTO THE GREAT LAKES. A
SOUTHERLY FLOW AROUND THE HIGH WILL CONTINUE TO USHER IN WARM AND
HUMID CONDITIONS ACROSS OUR AREA.
LOW CLDS AND FOG ASSOCD WITH THE NOCTURNAL INVERSION LESS
PRONOUNCED THAN YDA...AND ITS BURNING AWAY QUICKER. THEREFORE...
THERE SHUD BE LESS OF A MAXT SPREAD THAN THERE WAS YDA. STILL...HV
TWEAKED I-95 CRRDR DOWN A DEGF OR TWO TO ACCNT FOR ITS IMPACT.
THE WARM AND HUMID AIRMASS IN PLACE WILL LEAD TO HIGH AMOUNTS OF
INSTABILITY. UNMODIFIED LWX RAOB REFLECTS THIS...BUT ALSO
HIGHLIGHTS THE CAPPING INHIBITION BTWN H9-8. HGTS SHUD BE DROPPING
TAFTN AS TROF AXIS CROSSES THE WRN GRTLKS. MODIFYING THE SNDG FOR
T/TD 88/68 YIELDS ARND 3000 J/KG OF SBCAPE W/O A CAP. MLCAPE MUCH
MORE RESERVED AND SLGTLY INHIBITED.
TERRAIN CIRCULATIONS AND A SURFACE TROUGH WILL ACT AS LIFTING
MECHANISMS FOR CONVECTION THIS AFTERNOON. THIS IS ALSO SIMILAR TO
TUESDAY. THEREFORE...A BETTER CHANCE FOR THUNDERSTORMS EXISTS THIS
AFTERNOON AND EVENING...ESPECIALLY NEAR AND WEST OF THE I-95
CORRIDOR. HV ADJUSTED POPS SLGTLY TO PLACE MORE EMPHASIS ON
APLCHNS AND DEEMPHASIZE INVOF CHESPK BAY. HRRR /WRF-ARW4 BOTH
SUGGEST THAT TSRA SHUD FIRE TAFTN W OF THE BLURDG...SPCLY AFTR
18Z. WL NEED TO WATCH THAT TIMING THO...AS RADAR TRENDS IN WVA
ATTM SUGGEST IT MAY BE ERLR.
ALTHOUGH WIDESPREAD SEVERE WEATHER WILL LIKELY HOLD OFF TO OUR
WEST FOR LOCATIONS CLOSER TO THE UPPER-LEVEL TROUGH...THERE IS A
THREAT FOR LOCALLY DAMAGING WIND GUSTS AND LARGE HAIL IN ANY
THUNDERSTORMS THAT DO DEVELOP DUE TO THE HIGH INSTABILITY.
CONVECTION WILL LIKELY DISSIPATE LATER THIS EVENING DUE TO THE LOSS
OF DAYTIME HEATING. HOWEVER...AN UPPER-LEVEL DISTURBANCE IS EXPECTED
TO PASS THROUGH THE REGION LATE TONIGHT AS THE UPPER-LEVEL TROUGH
CONTINUES TO SLIDE CLOSER TO OUR AREA. PLENTY OF MOISTURE AND
FORCING FROM THE UPPER-LEVEL DISTURBANCE MAY RESULT IN SCATTERED
SHOWERS/T-STORMS TOWARD MORNING. MIN TEMPS TONIGHT WILL RANGE FROM
THE 50S IN THE MOUNTAINS TO THE LOWER AND MIDDLE 70S IN DOWNTOWN
WASHINGTON/BALTIMORE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
THURSDAY LOOKS TO BE THE LAST ABOVE NORMAL TEMPERATURE DAY FOR
AWHILE AHEAD OF THE COLD FRONT THAT CROSSES THURSDAY NIGHT
TIMEFRAME. PREFRONTAL LINES/CLUSTERS OF SHOWERS/THUNDERSTORMS
PROGRESS EAST ACROSS THE AREA THURSDAY INTO THURSDAY NIGHT. GFS BUFR
SNDG FOR KIAD PROGS A 1.6 INCH PWAT WHICH IS CERTAINLY HIGH...BUT
JUST SHY OF THE 2 STDEV INDICATOR OF FLASH FLOODING. WITH
PROGRESSIVE NATURE OF THE ACTIVITY...ANY FLASH FLOODING WOULD BE
LOCALIZED. DAMAGING WIND THREAT...PARTICULARLY WITH HEATING ON
THURSDAY IS ABLE TO PEAK BEFORE ORGANIZED ACTIVITY MOVES THROUGH.
FRIDAY...UPR TROUGH DRIFTS EAST OVER THE AREA WITH BACK EDGE OF
CLOUDS SLOW TO COME IN THE AFTERNOON. GUSTY NWLY FLOW FRIDAY
CONTINUES AS HIGH PRESSURE BUILDS THROUGH SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SHORTWAVE FROM TN VLY ON SUNDAY NOW LOOKS TO EXPAND EAST ACROSS THE
SOUTHERN-CENTRAL MID-ATLANTIC. CONVERGENCE ALONG THIS BOUNDARY WOULD
SET OFF SHOWERS. PATTERN IS STALLED INTO MID NEXT WEEK...SO A
PROLONGED CLOUDY/RAINY PERIOD IS POSSIBLE. THIS WOULD RESULT IN
BELOW NORMAL TEMPS.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
LOW CLOUDS BURNING OFF ATTM. MVFR AT DCA/MTN...BUT ANTICIPATE VFR
EVERYWHERE BY 15Z.
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AFTN...PRIMARILY
INVOF MRB. SOME OF THE THUNDERSTORMS WILL BE CAPABLE OF PRODUCING
GUSTY WINDS AND LARGE HAIL. AREAS OF LOW CLOUDS ARE POSSIBLE LATE
TONIGHT ALONG WITH SCATTERED SHOWERS/T-STORMS.
THUNDERSTORMS THURSDAY INTO THURSDAY EVENING AHEAD OF A COLD FRONT.
IFR CONDS POSSIBLE IN THE HEAVIEST ACTIVITY. SLY FLOW UNTIL A COLD
FROPA THURSDAY NIGHT. NWLY FLOW WITH GUSTS 25 TO POSSIBLY 30 KT WITH
MID LEVEL CIGS FRIDAY. NWLY FLOW CONTINUES THROUGH SATURDAY AS HIGH
PRESSURE BUILDS.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE ATLANTIC OCEAN THROUGH TONIGHT. A
SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS DURING THIS TIME. A
SMALL CRAFT ADVISORY REMAINSS IN EFFECT FOR PORTIONS OF THE WATERS
THROUGH TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
LATER THIS AFTERNOON AND EVENING. ANY THUNDERSTORMS THAT DO
DEVELOP WILL BE CAPABLE OF PRODUCING GUSTY WINDS AND HAIL.
SLY FLOW AHEAD OF A LATE THURSDAY NIGHT COLD FRONT. SCA EXPANDED
THROUGH THURSDAY. EXPECT AN EXTENSION THURSDAY NIGHT FOR PREFRONTAL
SLY FLOW...THEN NWLY FLOW AROUND 25 KT FRIDAY THROUGH SATURDAY AS
HIGH PRESSURE BUILDS.
&&
.TIDES/COASTAL FLOODING...
A SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS THROUGH THURSDAY
NIGHT...BUT THE FLOW MAY REMAIN JUST WEST OF SOUTH. TIDAL ANOMALIES
WILL LIKELY INCREASE A LITTLE...BUT WITH THE FLOW REMAINING WEST OF
SOUTH THE WATER LEVELS SHOULD REMAIN BELOW THRESHOLDS FOR MINOR
COASTAL FLOODING. THE CLOSEST WATER LEVELS WILL COME TO MINOR
FLOODING THRESHOLDS WILL BE DURING THE HIGH TIDE CYCLE LATE WEDNESDAY
NIGHT AND LATE THURSDAY NIGHT...THE HIGHER OF THE TWO HIGH TIDES.
TIDAL ANOMALIES WILL DECREASE FRIDAY BEHIND A COLD FRONT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT
THURSDAY FOR ANZ530-531-539.
SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT THURSDAY FOR ANZ535-
538.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EDT
THURSDAY FOR ANZ532-536-540-542.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ533-534-
537-541-543.
&&
$$
SYNOPSIS...BJL
NEAR TERM...HTS/BJL
SHORT TERM...BAJ
LONG TERM...BAJ
AVIATION...HTS/BJL/BAJ
MARINE...KLEIN/BJL/BAJ
TIDES/COASTAL FLOODING...BJL
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
950 AM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 949 AM CDT WED MAY 22 2013
UPDATED THE FORECAST FOR TRENDS IN CLOUD COVER AND PRECIPITATION.
THE SURFACE LOW WHICH HAS THE MOISTURE ROTATING AROUND IT IS NOW
OVER NORTHEAST IOWA AS OF 14Z...WHILE HIGH PRESSURE BUILDS INTO
THE PANHANDLE AND WESTERN NEBRASKA. THE CLOUD COVER WAS STARTING
TO BREAK UP THIS MORNING...MAINLY OVER THE SOUTHWEST PARTS OF THE
FORECAST AREA. THERE IS A NARROW BAND FROM APPROXIMATELY KOGA TO
KCDR THAT MAY PERSIST A BIT LONGER...BUT EXPECTING THIS AREA TO
MIX OUT AND DISSIPATE BY THE NOON HOUR. GOING FURTHER EAST...THE
CLOUDS WILL LIKELY PERSIST THROUGH MUCH OF THE DAY...OR AT LEAST
THROUGH MID AFTERNOON AS A THICKER LAYER OF MOISTURE WILL REMAIN.
THE SHOWERS HAVE DECREASED IN AREA AND INTENSITY BY LATE THIS
MORNING...WITH THE STRONGER ECHOES NOW OVER EASTERN NEBRASKA AND
EASTERN SOUTH DAKOTA...CLOSER TO THE SURFACE LOW. WILL KEEP
MENTION OF SHOWERS AND SPRINKLES ACROSS NORTH CENTRAL AND CENTRAL
NEBRASKA THROUGH THE MORNING...THEN DRY CONDITIONS EXPECTED FOR
THE AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT WED MAY 22 2013
WRAP AROUND CLOUDINESS WILL CONTINUE TODAY ACROSS NRN NEB. THE LIGHT
RAIN SHOULD END BY NOON. THERE IS ONE MORE IMPULSE ACROSS ERN SD
WHICH WILL DROP SOUTH BEFORE THE SFC LOW DRIFTS EAST INTO THE
MIDWEST THIS AFTERNOON. THIS LEAVES MUCH OF THE SRN HALF OF THE FCST
AREA IN PARTLY CLOUDY SKIES WITH HIGHS IN THE 60S WHILE OVERCAST
SKIES KEEP THE NORTH IN THE 50S.
TONIGHT...AN INVERTED SFC LOW PRESSURE TROF WILL SHARPEN UP ACROSS
THE NRN AND CNTL ROCKIES. THIS WILL SET UP A BROAD BELT OF
EASTERLIES ACROSS THE FCST AREA WHICH COULD TRAP LOW LEVEL MOISTURE
AND PRODUCE UPSLOPE FOG AND STRATUS ACROSS WRN NEB. PRESUMABLY...DRY
AIR COULD MOVE INTO NCNTL NEB CLEARING SKIES THERE. GIVEN THE POOR
MODEL PERFORMANCE OF THE NAM IN THESE TYPES OF SITUATIONS...THE RAP
MODEL MIGHT BE THE BEST HANDLE FOR TONIGHTS SKY FORECAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 345 AM CDT WED MAY 22 2013
SFC HIGH PRESSURE WILL MOVE EAST OF THE REGION THURSDAY...WITH EAST
TO SOUTHEAST WINDS KEEPING CONDITIONS RATHER COOL...WITH HIGHS IN
THE 60S TO PERHAPS 70 IN A FEW LOCALS. INCREASING LOW LEVEL MOISTURE
COULD LEAD TO SOME STRATUS DEVELOPMENT...ESPECIALLY ACROSS SOUTHWEST
NEB AND THE PANHANDLE...WHICH COULD HOLD HIGHS DOWN FURTHER. A
SOUTHERLY LLJ CRACKS UP TO AROUND 45 KTS...ADVECTING MORE MOISTURE
AND BETTER CHANCES FOR STRATUS CLOUDS INTO THE AREA. WILL MAINTAIN A
SLIGHT CHANCE FOR SHOWERS/TSTMS ACROSS SOUTHWEST NEBRASKA...WHERE
WARM AIR ADVECTION WILL BE MAXIMIZED.
FRIDAY THROUGH TUESDAY APPEARS TO BE QUITE ACTIVE IN TERMS OF
CONVECTIVE POTENTIAL. A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL
BECOME ANCHORED ACROSS THE PACIFIC NORTHWEST...PROVIDING A SOUTHWEST
FLOW ALOFT ACROSS THE CENTRAL CONUS. THIS FLOW DOESN/T APPEAR OVERLY
STRONG...BUT ADEQUATE ENOUGH TO SUPPORT SOME SEVERE TSTM POTENTIAL
FROM TIME TO TIME. MEANWHILE...PLENTY OF LOW LEVEL MOISTURE AND
STEEP MID LEVEL LAPSE RATES...WILL RESULT IN STRONG INSTABILITY
DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS THAT A LEEWARD
TROUGH/DRY LINE WILL BE ESTABLISHED EACH AFTERNOON ACROSS WESTERN
NEB/KS...AND COULD SERVE AS A FOCUS FOR CONVECTIVE INITIATION AS
SHORTWAVE TROUGHS EJECT EASTWARD FROM THE WESTERN UPPER LOW. OF
COURSE TIMING OF THESE TROUGHS WILL BE A FACTOR...AND LATER
FORECASTS WILL REFINE THE TIMING AND INTENSITY OF ANY TSTMS.
TEMPERATURES THROUGH THE PERIOD COULD BE A CHALLENGE...ESPECIALLY
HIGH TEMPERATURES...AS POTENTIAL EXISTS FOR QUITE A BIT IN THE WAY
OF STRATUS CLOUDS DUE TO INCREASED GULF OF MEXICO MOISTURE...AND ANY
CONVECTIVE DEBRIS CLOUDINESS. FOR NOW WILL GO WITH HIGHS MAINLY IN
THE LOWER 70S TO LOWER 80S...WITH THE WARMEST READINGS ACROSS THE
WESTERN PORTIONS OF THE AREA. LOWS WILL BE MILD...MID 50S TO LOWER
60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 622 AM CDT WED MAY 22 2013
IFR ACROSS NRN NEB SHOULD IMPROVE TO MVFR THIS MORNING WHILE THE
MVFR ALONG I-80 IMPROVES TO VFR. TONIGHT...UPSLOPE EASTERLIES
DEVELOP AND MVFR/IFR IS EXPECTED TO REDEVELOP ACROSS WRN NEB
PERHAPS AFFECTING THE KLBF TERMINAL. MEANWHILE...THE RAP MODEL
SUGGESTS CLEARING ACROSS NERN NEB AND THE KVTN TERMINAL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BROOKS
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
627 AM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 625 AM CDT WED MAY 22 2013
AS DISCUSSED EARLIER...ENDED UP MAKING A FEW ADJUSTMENTS TO VERY
SHORT TERM GRIDS BASED ON LATEST RADAR TRENDS...AND WITH SUPPORT
FROM THE LATEST RAP13/HRRR QPF/REFLECTIVITY. ALTHOUGH CANNOT RULE
OUT A FEW SPOTS REPORTING LIGHT MEASURABLE RAIN WITH THIS
ACTIVITY...ESPECIALLY IN THE NANCE/POLK COUNTY AREA...THINK THAT
NON-MEASURABLE SPRINKLES WILL BE THE DOMINANT STORY FOR MOST OF
THE AFFECTED AREA...AND THUS LEFT OUT A MEASURABLE POP.
HOWEVER...BEEFED UP SPRINKLE WORDING TO WIDESPREAD IN SEVERAL FAR
NORTHEAST COUNTIES THROUGH NOON 17Z...AND EXPANDED AN ISOLATED
SPRINKLE MENTION AS FAR SOUTH AS A LOUP CITY-GENEVA LINE. IT MAY
TURN OUT THAT THIS LIGHT PRECIP MAY BE OUT OF THE PICTURE WELL
BEFORE NOON...BUT GIVEN THE VERY SLOW MOVING NATURE OF THE PARENT
MID LEVEL LOW TO THE EAST ANYTHING IS POSSIBLE. ALSO BEEFED UP SKY
COVER PERCENTAGES FROM MOSTLY CLOUDY TO OUTRIGHT CLOUDY ACROSS
ROUGHLY THE NORTHEAST 1/2 OF THE CWA THROUGH MID-DAY...WHILE
LEAVING A MORE OPTIMISTIC TREND IN PLACE FARTHER SOUTHWEST. THE
LATEST HRRR IS NOW SPORTING A ROUGHLY 20 DEGREE HIGH-TEMP GRADIENT
ACROSS THE CWA THIS AFTERNOON FROM ONLY LOW-MID 50S NORTHEAST TO
MID 70S SOUTHWEST. OTHER SHORT TERM MODELS SUCH AS THE RAP13 ARE
NOT AS COOL IN THE NORTHEAST AS THE HRRR...AND THUS WILL RESIST
THE URGE TO MODIFY AFTERNOON HIGHS AT THIS TIME...BUT FOR SURE ITS
POSSIBLE THAT SOME NORTHEAST AREAS COULD STRUGGLE TO REACH THE
MID-UPPER 50S AND NEXT SHIFT WILL HAVE MONITOR TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM CDT WED MAY 22 2013
WHILE THERE IS CERTAINLY NO HIGH-IMPACT WEATHER DURING THE NEXT
24 HOURS...THERE ARE AT LEAST A FEW TRICKY ELEMENTS AT
HAND...INCLUDING THE EXTENT OF LOW STRATUS AND ITS POSSIBLE
INFLUENCE ON A FAIRLY DECENT SOUTHWEST-NORTHEAST TEMP
GRADIENT...AND ALSO THE EXTENT OF SPRINKLES/LIGHT RAIN SHOWERS
MAINLY THIS MORNING IN THE NORTHEAST.
08Z OBJECTIVE SURFACE ANALYSIS REVEALS NO MAJOR FEATURES ACROSS
THE CENTRAL PLAINS...WITH THE CWA POSITIONED BETWEEN A MODEST 1004
MILLIBAR LOW OVER EASTERN IA...AND A 1014MB HIGH OVER THE NEB
PANHANDLE...A SOUTHWARD EXTENSION OF A STRONGER...BROADER HIGH
WELL TO THE NORTH IN CANADA. WITHIN THE MODEST PRESSURE GRADIENT
BETWEEN THESE FEATURES...A FAIRLY STEADY NORTH-NORTHWEST BREEZE OF
10-15 MPH HAS PREVAILED THROUGH THE NIGH IN MOST AREAS...WITH
OCCASIONAL GUSTS OVER 20 MPH. TEMPERATURES WILL START OUT THE
MORNING SEASONABLY COOL...WITH EVENTUAL LOWS AIMED INTO THE MID-
UPPER 40S ALL AREAS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM
MODEL DATA FEATURES A CLOSED 500MB LOW DRIFTING SLOWLY
EAST...CENTERED NEAR THE IA/SD/NEB BORDER...AND A FAIRLY SHARP MID
LEVEL TROUGH AXIS THEN TRAILING SOUTH-SOUTHEAST INTO THE MID-SOUTH
STATES. OFF TO THE WEST OF THE LOCAL AREA...A LOW AMPLITUDE MID
LEVEL RIDGE IS ALIGNED NORTH-SOUTH THROUGH THE ROCKIES...WITH A
FAIRLY VIGOROUS...EXPANSIVE CLOSED LOW SPINNING OVER THE PACIFIC
NORTHWEST. WHILE IT HAS TAKEN ITS TIME FORMING...11-3.9 MICRON
SATELLITE IMAGERY AND AUTOMATED OBS HAVE FINALLY REVEALED THE
FORMATION OF FAIRLY WIDESPREAD LOW STRATUS MAINLY IN THE 1500-2500
FT RANGE OVER MUCH OF THE CWA...ALTHOUGH SOME BREAKS IN THE CLOUDS
DO STILL EXIST. ALSO JUST WITHIN THE PAST 90 MINUTES OR SO...AN
INCREASING FLARE-UP OF LIGHT RAIN/SPRINKLES HAS TAKEN PLACE MAINLY
OVER THE FAR NORTHERN/NORTHEAST CWA...WITH UPSTREAM OBS AT PLACES
SUCH AS ONEILL AND ALBION CONFIRMING AT LEAST TRACE AMOUNTS ARE
FALLING.
TODAY...THE MAIN STORY ALOFT INVOLVES THE CONTINUED SLOW DEPARTURE
OF THE CLOSED MID LEVEL LOW...WITH THE CENTER OF THIS FEATURE
PROGGED TO ONLY REACH NORTHEAST IA BY 00Z. AT THE SURFACE...A
MODEST PRESSURE GRADIENT WILL REMAIN IN PLACE AS HIGH PRESSURE TO
THE NORTH NOSES SOUTHWARD...AND THIS IN COMBINATION WITH MIXING TO
AT LEAST 850MB IN MOST AREAS WILL RESULT IN SOMEWHAT BREEZY
CONDITIONS ESPECIALLY WITHIN THE NORTHEAST 2/3 OF THE CWA...WITH
SUSTAINED NORTHWEST WINDS 15 TO POSSIBLY 20 MPH...AND SOME HIGHER
GUSTS. THE REAL CHALLENGE TODAY LIES INITIALLY WITH THE EXTENT AND
INTENSITY OF RAINFALL...AND ALSO JUST HOW STUBBORN THE LOW STRATUS
DECK WILL BE...AND WHETHER OR NOT IT RETREATS SLOW NORTHEAST
DURING THE AFTERNOON. STARTING OUT EARLY THIS MORNING THROUGH MID-
DAY...HAVE INTRODUCED A MENTION OF SPRINKLES TO A PREVIOUSLY
PRECIP-FREE FORECAST FOR FAR NORTHEAST AREAS MAINLY NORTH OF A
GREELEY-POLK LINE...AS DECENT LOW-MID LEVEL SATURATION UP TO
AROUND 600MB RESIDES MAINLY IN THIS ZONE AND POINTS
NORTHEAST...ASSOCIATED WITH A BATCH OF MID LEVEL MOISTURE FOCUSED
IN THE DEFORMATION ZONE ON THE BACK-SIDE OF THE DEPARTING LOW. THE
VERY SHORT TERM QUESTION THAT WILL NEED PONDERED OVER THE NEXT FEW
HOURS IS WHETHER TO EXPAND THIS SPRINKLE MENTION SOUTHWESTWARD
CLOSER TO I-80 PER SUGGESTION OF THE LATEST HRRR REFLECTITY
PROG...AND ALSO WHETHER TO UP THE ANTE TO A MEASURABLE POP. WILL
GIVE IT SOME TIME TO SEE IF AREA OBSERVATIONS SUPPORT A FEW
HUNDREDTHS OF ACCUMULATIONS BEFORE POSSIBLY MAKING THIS MOVE. AT
ANY RATE...ANY LIGHT RAINFALL IN THE NORTHEAST...ESPECIALLY OF THE
POTENTIALLY MEASURABLE VARIETY...IS EXPECTED TO BE OUT OF THE
PICTURE BY NOON...AS THE MID LEVELS START TO DRY OUT FROM WEST TO
EAST. CLOUD-WISE...HAVE LEANED TOWARD A COMBINATION OF THE NAM AND
HRRR...WITH THE EXPECTATION OF A RATHER SHARP SOUTHWEST-NORTHEAST
GRADIENT RANGING FROM MOSTLY SUNNY-PARTLY CLOUDY SOUTHWEST TO
MOSTLY CLOUDY AT BEST IN THE NORTHEAST. SHAKY CONFIDENCE IN THESE
CLOUD DETAILS LEAD TO SOMEWHAT SHAKY CONFIDENCE IN HIGH TEMPS. AT
LEAST FOR NOW...NUDGED SOUTHWEST AREAS UP A FEW DEGREES AND
NORTHEAST AREAS DOWN A FEW DEGREES VERSUS PREVIOUS...WHILE LEAVING
THE CENTRAL RATHER UNCHANGED. AS A RESULT...AM AIMING FROM UPPER
50S-LOW 60S FAR NORTH/NORTHEAST TO MID 60S TRI-CITIES TO MID 70S
SOUTHWEST. HOWEVER...AM STARTING TO WONDER IF THE HRRR MIGHT BE
ONTO SOMETHING...KEEPING MUCH OF THE NORTHEAST 1/2 OF THE CWA WELL
DOWN IN THE MID-50S AT BEST UNDER THE LONGEST-LASTING STRATUS.
THIS WILL BEAR WATCHING FOR LATER UPDATES...BUT DON/T WANT TO GO
QUITE THIS COOL YET.
TURNING TO THE TONIGHT PERIOD...00Z-12Z...CONFIDENCE REMAINS
RATHER HIGH IN A LEGITIMATELY DRY NIGHT...WITH THE SOLE POSSIBLE
EXCEPTION OF SOME PATCHY LIGHT DRIZZLE IN THE EVENING IN THE NORTH
UNDER A LOW STRATUS DECK...BUT THIS SCENARIO IS TOO UNCERTAIN TO
INSERT AT THIS TIME. IN THE MID-UPPER LEVELS...THE DEPARTING LOW
FINALLY SLIPS FAR ENOUGH EAST TO ALLOW THE RIDGE TO THE WEST TO
START BUILDING INTO NEB/KS. ALTHOUGH THERE WILL BE A MODEST
NORTHWEST-SOUTHEAST ORIENTED WING OF MID LEVEL MOISTURE
ADVECTION/ISENTROPIC LIFT THAT SETS UP FROM SOUTHWEST NEB TO
SOUTHEAST KS MAINLY AFTER MIDNIGHT AS EVIDENT ON THE 310K
SURFACE...SOUNDINGS SUGGEST THAT LIFT/MOISTURE SHOULD BE
INSUFFICIENT FOR PRECIP OVER THE CWA...ALTHOUGH A FEW SHOWERS OR
EVEN WEAK STORMS COULD FLARE UP WITHIN A FEW COUNTIES JUST TO THE
SOUTH/SOUTHWEST BY SUNRISE. AT THE SURFACE...HIGH PRESSURE WILL
CONTINUE OOZING DOWN FROM THE NORTH...KEEPING FAIRLY LIGHT BUT
STEADY NORTHERLY BREEZES AROUND 10 MPH IN PLACE. DESPITE THE
PRESENCE OF POTENTIALLY DECENT LOW LEVEL SATURATION...THESE
BREEZES SHOULD KEEP ANYTHING MORE THAN HAZE/LIGHT FOG AT BAY. THE
REAL QUESTION MARK AT THIS POINT TONIGHT AGAIN LIES WITH LOW
STRATUS TRENDS. WHILE THE PREVIOUS FORECAST HAD NO WORSE THAN
PARTLY CLOUDY SKIES...THE LATEST NAM RUNS AND ASSOCIATED MET
GUIDANCE FAIRLY AGGRESSIVELY BRING A BATCH OF LOW STRATUS BACK
SOUTHWARD ACROSS MOST OF THE CWA AS THE NIGHT WEARS ON...WITH THIS
ESPECIALLY EVIDENT AT 900MB. FOR NOW...HAVE STARTED AN UPWARD
TREND IN SKY COVER...BUT VERY WELL MAY NOT BE HIGH ENOUGH
ESPECIALLY POST-MIDNIGHT. EVEN IF STRATUS DOES END UP BEING MORE
WIDESPREAD THAN CURRENTLY SUGGESTED...CONFIDENCE IS DECENT THAT
LOW TEMPS WILL END UP SIMILAR TO THOSE OF THIS MORNING...AND USED
A BLEND OF MET/MAV GUIDANCE...AIMING FOR ANOTHER COOL ONE WITH MID
40S MOST SPOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 509 AM CDT WED MAY 22 2013
MODELS ARE IN GOOD AGREEMENT TRANSITIONING A RIDGE OF HIGH PRESSURE
ACROSS THE PLAINS ON THURSDAY IN WAKE OF THE DEPARTING UPPER LEVEL
LOW. WHILE HEIGHTS ALOFT WILL BE RISING...EXPECT ONLY A MODESTLY
WARMER AFTERNOON ON THURSDAY AS 850MB TEMPS ARE EXPECTED TO ONLY
REBOUND A COUPLE OF DEGREES AND PLENTY OF CLOUD COVER IS EXPECTED IN
EASTERLY UPSLOPE FLOW.
AS THE WINDS SHIFT MORE SOUTHEASTERLY THURSDAY NIGHT AND
FRIDAY...EXPECT ADDITIONAL MOISTURE TO SURGE NORTHWARD...AND FOR
INCREASING INSTABILITY ACROSS THE REGION. THIS BUILDING INSTABILITY
COMBINED WITH SOME FORCING FROM THE LOW LEVEL JET...WILL LIKELY
RESULT IN A CHANCE OF THUNDERSTORMS THURSDAY NIGHT ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA...WHICH WILL BE IN CLOSER
PROXIMITY TO THE JET. WITH THE NOSE OF THE NOCTURNAL JET MORE
FOCUSED ACROSS THE HEART OF LOCAL AREA FRIDAY AND FRIDAY
NIGHT...CANNOT RULE OUT ADDITIONAL ELEVATED SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCES FOR
PRECIPITATION COMING DURING THE LATE EVENING AND OVERNIGHT HOURS.
THEREAFTER THE MID LEVEL CAP IS EXPECTED TO WEAKEN SUBSTANTIALLY BY
SATURDAY AFTERNOON... AND WITH SEVERAL THOUSAND JOULES OF CAPE TO
WORK WITH THROUGH THE REMAINDER OF THE LONG TERM PERIODS...WILL
LIKELY SEE THUNDERSTORMS AROUND EACH DAY AS PERIODIC VORTICITY
MAXIMA EJECT OUT OF THE LONGWAVE TROUGH ACROSS THE WEST COAST.
ADDITIONALLY...WITH THESE SUBSTANTIAL CAPE VALUES AND MARGINALLY
SUPPORTIVE SHEAR PROFILES...WILL HAVE THE POTENTIAL FOR SOME SEVERE
THUNDERSTORMS DEVELOP FROM TIME TO TIME SATURDAY ONWARD...WITH LARGE
HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY THREATS.
TEMPERATURES THROUGH THE PERIOD ARE NOT EXPECTED TO FLUCTUATE A
WHOLE LOT AS THERE WILL BE LITTLE CHANGE IN THE UNDERLYING AIRMASS
SATURDAY ONWARD...WITH LOWER TO MIDDLE 80S EXPECTED EACH AFTERNOON
AND LOWER 60S EXPECTED AT NIGHT.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z THURSDAY MORNING)
ISSUED AT 625 AM CDT WED MAY 22 2013
ALTHOUGH CONFIDENCE IS HIGH IN VFR VISIBILITY THROUGH THE
PERIOD...CEILING TRENDS CONTINUE TO BE TRICKY AS PLENTY OF LOWER
STRATUS HANGS AROUND THE AREA ON THE BACK SIDE OF A DEPARTING MID
LEVEL LOW. STARTING OFF THROUGH THE MORNING INTO THE MID-AFTERNOON
HOURS...HAVE CONTINUED A PREVAILING MVFR CEILING...ALTHOUGH JUST
WITHIN THE PAST HOUR CLOUDS AT THE MVFR LEVEL HAVE SCATTERED A
BIT...DIMINISHING CONFIDENCE SOMEWHAT AND SUGGESTING THAT MVFR
MAY BE MORE OFF-AND-ON. ALSO THIS MORNING...A FEW SPRINKLES CANNOT
BE RULED OUT AT KGRI...BUT GIVEN SUCH LOW IMPACT WILL OMIT ANY
PRECIP MENTION. THROUGH THE LATE AFTERNOON AND EVENING
HOURS...KEPT TREND FROM PREVIOUS FORECAST BY RAISING PREVAILING
CEILING TO LOW-END VFR. HOWEVER...CONFIDENCE IN THE DETAILS REALLY
DECREASES BY THE LAST 6 HOURS OR SO LATE TONIGHT...AS SOME
MODELS/GUIDANCE SUGGEST A LOW-MVFR AND POSSIBLY EVEN IFR DECK
COULD MATERIALIZE...WHILE OTHER MODELS KEEP CEILING VFR. AS A
COMPROMISE BETWEEN THE WIDE POSSIBILITIES AT THIS TIME
RANGE...WILL INTRODUCE A SCATTERED LOW-END MVFR CLOUD GROUP.
WIND-WISE...A STEADY NORTH-NORTHWEST BREEZE WILL PREVAIL MUCH OF
THE DAY WITH GUST POTENTIAL TO AROUND 22KT...BEFORE SLACKENING THIS
EVENING AND AVERAGING UNDER 10KT OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...PFANNKUCH
LONG TERM...SAR
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
625 AM CDT WED MAY 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT WED MAY 22 2013
WRAP AROUND CLOUDINESS WILL CONTINUE TODAY ACROSS NRN NEB. THE LIGHT
RAIN SHOULD END BY NOON. THERE IS ONE MORE IMPULSE ACROSS ERN SD
WHICH WILL DROP SOUTH BEFORE THE SFC LOW DRIFTS EAST INTO THE
MIDWEST THIS AFTERNOON. THIS LEAVES MUCH OF THE SRN HALF OF THE FCST
AREA IN PARTLY CLOUDY SKIES WITH HIGHS IN THE 60S WHILE OVERCAST
SKIES KEEP THE NORTH IN THE 50S.
TONIGHT...AN INVERTED SFC LOW PRESSURE TROF WILL SHARPEN UP ACROSS
THE NRN AND CNTL ROCKIES. THIS WILL SET UP A BROAD BELT OF
EASTERLIES ACROSS THE FCST AREA WHICH COULD TRAP LOW LEVEL MOISTURE
AND PRODUCE UPSLOPE FOG AND STRATUS ACROSS WRN NEB. PRESUMABLY...DRY
AIR COULD MOVE INTO NCNTL NEB CLEARING SKIES THERE. GIVEN THE POOR
MODEL PERFORMANCE OF THE NAM IN THESE TYPES OF SITUATIONS...THE RAP
MODEL MIGHT BE THE BEST HANDLE FOR TONIGHTS SKY FORECAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 345 AM CDT WED MAY 22 2013
SFC HIGH PRESSURE WILL MOVE EAST OF THE REGION THURSDAY...WITH EAST
TO SOUTHEAST WINDS KEEPING CONDITIONS RATHER COOL...WITH HIGHS IN
THE 60S TO PERHAPS 70 IN A FEW LOCALS. INCREASING LOW LEVEL MOISTURE
COULD LEAD TO SOME STRATUS DEVELOPMENT...ESPECIALLY ACROSS SOUTHWEST
NEB AND THE PANHANDLE...WHICH COULD HOLD HIGHS DOWN FURTHER. A
SOUTHERLY LLJ CRACKS UP TO AROUND 45 KTS...ADVECTING MORE MOISTURE
AND BETTER CHANCES FOR STRATUS CLOUDS INTO THE AREA. WILL MAINTAIN A
SLIGHT CHANCE FOR SHOWERS/TSTMS ACROSS SOUTHWEST NEBRASKA...WHERE
WARM AIR ADVECTION WILL BE MAXIMIZED.
FRIDAY THROUGH TUESDAY APPEARS TO BE QUITE ACTIVE IN TERMS OF
CONVECTIVE POTENTIAL. A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL
BECOME ANCHORED ACROSS THE PACIFIC NORTHWEST...PROVIDING A SOUTHWEST
FLOW ALOFT ACROSS THE CENTRAL CONUS. THIS FLOW DOESN/T APPEAR OVERLY
STRONG...BUT ADEQUATE ENOUGH TO SUPPORT SOME SEVERE TSTM POTENTIAL
FROM TIME TO TIME. MEANWHILE...PLENTY OF LOW LEVEL MOISTURE AND
STEEP MID LEVEL LAPSE RATES...WILL RESULT IN STRONG INSTABILITY
DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS THAT A LEEWARD
TROUGH/DRY LINE WILL BE ESTABLISHED EACH AFTERNOON ACROSS WESTERN
NEB/KS...AND COULD SERVE AS A FOCUS FOR CONVECTIVE INITIATION AS
SHORTWAVE TROUGHS EJECT EASTWARD FROM THE WESTERN UPPER LOW. OF
COURSE TIMING OF THESE TROUGHS WILL BE A FACTOR...AND LATER
FORECASTS WILL REFINE THE TIMING AND INTENSITY OF ANY TSTMS.
TEMPERATURES THROUGH THE PERIOD COULD BE A CHALLENGE...ESPECIALLY
HIGH TEMPERATURES...AS POTENTIAL EXISTS FOR QUITE A BIT IN THE WAY
OF STRATUS CLOUDS DUE TO INCREASED GULF OF MEXICO MOISTURE...AND ANY
CONVECTIVE DEBRIS CLOUDINESS. FOR NOW WILL GO WITH HIGHS MAINLY IN
THE LOWER 70S TO LOWER 80S...WITH THE WARMEST READINGS ACROSS THE
WESTERN PORTIONS OF THE AREA. LOWS WILL BE MILD...MID 50S TO LOWER
60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 622 AM CDT WED MAY 22 2013
IFR ACROSS NRN NEB SHOULD IMPROVE TO MVFR THIS MORNING WHILE THE
MVFR ALONG I-80 IMPROVES TO VFR. TONIGHT...UPSLOPE EASTERLIES
DEVELOP AND MVFR/IFR IS EXPECTED TO REDEVELOP ACROSS WRN NEB
PERHAPS AFFECTING THE KLBF TERMAINAL. MEANWHILE...THE RAP MODEL
SUGGESTS CLEARING ACROSS NERN NEB AND THE KVTN TERMINAL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
510 AM CDT WED MAY 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM CDT WED MAY 22 2013
WHILE THERE IS CERTAINLY NO HIGH-IMPACT WEATHER DURING THE NEXT
24 HOURS...THERE ARE AT LEAST A FEW TRICKY ELEMENTS AT
HAND...INCLUDING THE EXTENT OF LOW STRATUS AND ITS POSSIBLE
INFLUENCE ON A FAIRLY DECENT SOUTHWEST-NORTHEAST TEMP
GRADIENT...AND ALSO THE EXTENT OF SPRINKLES/LIGHT RAIN SHOWERS
MAINLY THIS MORNING IN THE NORTHEAST.
08Z OBJECTIVE SURFACE ANALYSIS REVEALS NO MAJOR FEATURES ACROSS
THE CENTRAL PLAINS...WITH THE CWA POSITIONED BETWEEN A MODEST 1004
MILLIBAR LOW OVER EASTERN IA...AND A 1014MB HIGH OVER THE NEB
PANHANDLE...A SOUTHWARD EXTENSION OF A STRONGER...BROADER HIGH
WELL TO THE NORTH IN CANADA. WITHIN THE MODEST PRESSURE GRADIENT
BETWEEN THESE FEATURES...A FAIRLY STEADY NORTH-NORTHWEST BREEZE OF
10-15 MPH HAS PREVAILED THROUGH THE NIGH IN MOST AREAS...WITH
OCCASIONAL GUSTS OVER 20 MPH. TEMPERATURES WILL START OUT THE
MORNING SEASONABLY COOL...WITH EVENTUAL LOWS AIMED INTO THE MID-
UPPER 40S ALL AREAS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM
MODEL DATA FEATURES A CLOSED 500MB LOW DRIFTING SLOWLY
EAST...CENTERED NEAR THE IA/SD/NEB BORDER...AND A FAIRLY SHARP MID
LEVEL TROUGH AXIS THEN TRAILING SOUTH-SOUTHEAST INTO THE MID-SOUTH
STATES. OFF TO THE WEST OF THE LOCAL AREA...A LOW AMPLITUDE MID
LEVEL RIDGE IS ALIGNED NORTH-SOUTH THROUGH THE ROCKIES...WITH A
FAIRLY VIGOROUS...EXPANSIVE CLOSED LOW SPINNING OVER THE PACIFIC
NORTHWEST. WHILE IT HAS TAKEN ITS TIME FORMING...11-3.9 MICRON
SATELLITE IMAGERY AND AUTOMATED OBS HAVE FINALLY REVEALED THE
FORMATION OF FAIRLY WIDESPREAD LOW STRATUS MAINLY IN THE 1500-2500
FT RANGE OVER MUCH OF THE CWA...ALTHOUGH SOME BREAKS IN THE CLOUDS
DO STILL EXIST. ALSO JUST WITHIN THE PAST 90 MINUTES OR SO...AN
INCREASING FLARE-UP OF LIGHT RAIN/SPRINKLES HAS TAKEN PLACE MAINLY
OVER THE FAR NORTHERN/NORTHEAST CWA...WITH UPSTREAM OBS AT PLACES
SUCH AS ONEILL AND ALBION CONFIRMING AT LEAST TRACE AMOUNTS ARE
FALLING.
TODAY...THE MAIN STORY ALOFT INVOLVES THE CONTINUED SLOW DEPARTURE
OF THE CLOSED MID LEVEL LOW...WITH THE CENTER OF THIS FEATURE
PROGGED TO ONLY REACH NORTHEAST IA BY 00Z. AT THE SURFACE...A
MODEST PRESSURE GRADIENT WILL REMAIN IN PLACE AS HIGH PRESSURE TO
THE NORTH NOSES SOUTHWARD...AND THIS IN COMBINATION WITH MIXING TO
AT LEAST 850MB IN MOST AREAS WILL RESULT IN SOMEWHAT BREEZY
CONDITIONS ESPECIALLY WITHIN THE NORTHEAST 2/3 OF THE CWA...WITH
SUSTAINED NORTHWEST WINDS 15 TO POSSIBLY 20 MPH...AND SOME HIGHER
GUSTS. THE REAL CHALLENGE TODAY LIES INITIALLY WITH THE EXTENT AND
INTENSITY OF RAINFALL...AND ALSO JUST HOW STUBBORN THE LOW STRATUS
DECK WILL BE...AND WHETHER OR NOT IT RETREATS SLOW NORTHEAST
DURING THE AFTERNOON. STARTING OUT EARLY THIS MORNING THROUGH MID-
DAY...HAVE INTRODUCED A MENTION OF SPRINKLES TO A PREVIOUSLY
PRECIP-FREE FORECAST FOR FAR NORTHEAST AREAS MAINLY NORTH OF A
GREELEY-POLK LINE...AS DECENT LOW-MID LEVEL SATURATION UP TO
AROUND 600MB RESIDES MAINLY IN THIS ZONE AND POINTS
NORTHEAST...ASSOCIATED WITH A BATCH OF MID LEVEL MOISTURE FOCUSED
IN THE DEFORMATION ZONE ON THE BACK-SIDE OF THE DEPARTING LOW. THE
VERY SHORT TERM QUESTION THAT WILL NEED PONDERED OVER THE NEXT FEW
HOURS IS WHETHER TO EXPAND THIS SPRINKLE MENTION SOUTHWESTWARD
CLOSER TO I-80 PER SUGGESTION OF THE LATEST HRRR REFLECTITY
PROG...AND ALSO WHETHER TO UP THE ANTE TO A MEASURABLE POP. WILL
GIVE IT SOME TIME TO SEE IF AREA OBSERVATIONS SUPPORT A FEW
HUNDREDTHS OF ACCUMULATIONS BEFORE POSSIBLY MAKING THIS MOVE. AT
ANY RATE...ANY LIGHT RAINFALL IN THE NORTHEAST...ESPECIALLY OF THE
POTENTIALLY MEASURABLE VARIETY...IS EXPECTED TO BE OUT OF THE
PICTURE BY NOON...AS THE MID LEVELS START TO DRY OUT FROM WEST TO
EAST. CLOUD-WISE...HAVE LEANED TOWARD A COMBINATION OF THE NAM AND
HRRR...WITH THE EXPECTATION OF A RATHER SHARP SOUTHWEST-NORTHEAST
GRADIENT RANGING FROM MOSTLY SUNNY-PARTLY CLOUDY SOUTHWEST TO
MOSTLY CLOUDY AT BEST IN THE NORTHEAST. SHAKY CONFIDENCE IN THESE
CLOUD DETAILS LEAD TO SOMEWHAT SHAKY CONFIDENCE IN HIGH TEMPS. AT
LEAST FOR NOW...NUDGED SOUTHWEST AREAS UP A FEW DEGREES AND
NORTHEAST AREAS DOWN A FEW DEGREES VERSUS PREVIOUS...WHILE LEAVING
THE CENTRAL RATHER UNCHANGED. AS A RESULT...AM AIMING FROM UPPER
50S-LOW 60S FAR NORTH/NORTHEAST TO MID 60S TRI-CITIES TO MID 70S
SOUTHWEST. HOWEVER...AM STARTING TO WONDER IF THE HRRR MIGHT BE
ONTO SOMETHING...KEEPING MUCH OF THE NORTHEAST 1/2 OF THE CWA WELL
DOWN IN THE MID-50S AT BEST UNDER THE LONGEST-LASTING STRATUS.
THIS WILL BEAR WATCHING FOR LATER UPDATES...BUT DON/T WANT TO GO
QUITE THIS COOL YET.
TURNING TO THE TONIGHT PERIOD...00Z-12Z...CONFIDENCE REMAINS
RATHER HIGH IN A LEGITIMATELY DRY NIGHT...WITH THE SOLE POSSIBLE
EXCEPTION OF SOME PATCHY LIGHT DRIZZLE IN THE EVENING IN THE NORTH
UNDER A LOW STRATUS DECK...BUT THIS SCENARIO IS TOO UNCERTAIN TO
INSERT AT THIS TIME. IN THE MID-UPPER LEVELS...THE DEPARTING LOW
FINALLY SLIPS FAR ENOUGH EAST TO ALLOW THE RIDGE TO THE WEST TO
START BUILDING INTO NEB/KS. ALTHOUGH THERE WILL BE A MODEST
NORTHWEST-SOUTHEAST ORIENTED WING OF MID LEVEL MOISTURE
ADVECTION/ISENTROPIC LIFT THAT SETS UP FROM SOUTHWEST NEB TO
SOUTHEAST KS MAINLY AFTER MIDNIGHT AS EVIDENT ON THE 310K
SURFACE...SOUNDINGS SUGGEST THAT LIFT/MOISTURE SHOULD BE
INSUFFICIENT FOR PRECIP OVER THE CWA...ALTHOUGH A FEW SHOWERS OR
EVEN WEAK STORMS COULD FLARE UP WITHIN A FEW COUNTIES JUST TO THE
SOUTH/SOUTHWEST BY SUNRISE. AT THE SURFACE...HIGH PRESSURE WILL
CONTINUE OOZING DOWN FROM THE NORTH...KEEPING FAIRLY LIGHT BUT
STEADY NORTHERLY BREEZES AROUND 10 MPH IN PLACE. DESPITE THE
PRESENCE OF POTENTIALLY DECENT LOW LEVEL SATURATION...THESE
BREEZES SHOULD KEEP ANYTHING MORE THAN HAZE/LIGHT FOG AT BAY. THE
REAL QUESTION MARK AT THIS POINT TONIGHT AGAIN LIES WITH LOW
STRATUS TRENDS. WHILE THE PREVIOUS FORECAST HAD NO WORSE THAN
PARTLY CLOUDY SKIES...THE LATEST NAM RUNS AND ASSOCIATED MET
GUIDANCE FAIRLY AGGRESSIVELY BRING A BATCH OF LOW STRATUS BACK
SOUTHWARD ACROSS MOST OF THE CWA AS THE NIGHT WEARS ON...WITH THIS
ESPECIALLY EVIDENT AT 900MB. FOR NOW...HAVE STARTED AN UPWARD
TREND IN SKY COVER...BUT VERY WELL MAY NOT BE HIGH ENOUGH
ESPECIALLY POST-MIDNIGHT. EVEN IF STRATUS DOES END UP BEING MORE
WIDESPREAD THAN CURRENTLY SUGGESTED...CONFIDENCE IS DECENT THAT
LOW TEMPS WILL END UP SIMILAR TO THOSE OF THIS MORNING...AND USED
A BLEND OF MET/MAV GUIDANCE...AIMING FOR ANOTHER COOL ONE WITH MID
40S MOST SPOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 509 AM CDT WED MAY 22 2013
MODELS ARE IN GOOD AGREEMENT TRANSITIONING A RIDGE OF HIGH PRESSURE
ACROSS THE PLAINS ON THURSDAY IN WAKE OF THE DEPARTING UPPER LEVEL
LOW. WHILE HEIGHTS ALOFT WILL BE RISING...EXPECT ONLY A MODESTLY
WARMER AFTERNOON ON THURSDAY AS 850MB TEMPS ARE EXPECTED TO ONLY
REBOUND A COUPLE OF DEGREES AND PLENTY OF CLOUD COVER IS EXPECTED IN
EASTERLY UPSLOPE FLOW.
AS THE WINDS SHIFT MORE SOUTHEASTERLY THURSDAY NIGHT AND
FRIDAY...EXPECT ADDITIONAL MOISTURE TO SURGE NORTHWARD...AND FOR
INCREASING INSTABILITY ACROSS THE REGION. THIS BUILDING INSTABILITY
COMBINED WITH SOME FORCING FROM THE LOW LEVEL JET...WILL LIKELY
RESULT IN A CHANCE OF THUNDERSTORMS THURSDAY NIGHT ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA...WHICH WILL BE IN CLOSER
PROXIMITY TO THE JET. WITH THE NOSE OF THE NOCTURNAL JET MORE
FOCUSED ACROSS THE HEART OF LOCAL AREA FRIDAY AND FRIDAY
NIGHT...CANNOT RULE OUT ADDITIONAL ELEVATED SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCES FOR
PRECIPITATION COMING DURING THE LATE EVENING AND OVERNIGHT HOURS.
THEREAFTER THE MID LEVEL CAP IS EXPECTED TO WEAKEN SUBSTANTIALLY BY
SATURDAY AFTERNOON... AND WITH SEVERAL THOUSAND JOULES OF CAPE TO
WORK WITH THROUGH THE REMAINDER OF THE LONG TERM PERIODS...WILL
LIKELY SEE THUNDERSTORMS AROUND EACH DAY AS PERIODIC VORTICITY
MAXIMA EJECT OUT OF THE LONGWAVE TROUGH ACROSS THE WEST COAST.
ADDITIONALLY...WITH THESE SUBSTANTIAL CAPE VALUES AND MARGINALLY
SUPPORTIVE SHEAR PROFILES...WILL HAVE THE POTENTIAL FOR SOME SEVERE
THUNDERSTORMS DEVELOP FROM TIME TO TIME SATURDAY ONWARD...WITH LARGE
HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY THREATS.
TEMPERATURES THROUGH THE PERIOD ARE NOT EXPECTED TO FLUCTUATE A
WHOLE LOT AS THERE WILL BE LITTLE CHANGE IN THE UNDERLYING AIRMASS
SATURDAY ONWARD...WITH LOWER TO MIDDLE 80S EXPECTED EACH AFTERNOON
AND LOWER 60S EXPECTED AT NIGHT.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1250 AM CDT WED MAY 22 2013
ALTHOUGH CONFIDENCE IS HIGH IN VFR VISIBILITY THROUGH THE
PERIOD...ALONG WITH LITTLE IF ANY RISK OF PRECIPITATION...CEILING
TRENDS APPEAR TO BE SOMEWHAT TRICKY AS PLENTY OF LOWER STRATUS
HANGS AROUND THE AREA ON THE BACK SIDE OF A DEPARTING MID LEVEL
LOW. STARTING OFF EARLY THIS MORNING...HAVE CONTINUED TO DELAY THE
ONSET OF PREVAILING MVFR CEILING UNTIL 09Z...ALTHOUGH AT LEAST
BRIEF INSTANCES OF MVFR MAY BE OBSERVED BEFORE THEN. LEANING
HEAVILY TOWARD LATEST CEILING TRENDS FROM 00Z NAM AND 05Z GFS LAMP
GUIDANCE...KEPT A BROKEN MVFR DECK IN PLACE THROUGH MID-
AFTERNOON...WHICH IS SEVERAL HOURS LATER THAN PREVIOUS FORECAST
INDICATED. CONFIDENCE STARTS TO WANE ESPECIALLY DURING THE FINAL 9
HOURS OR SO...BUT FOR NOW WILL AIM FOR A RETURN TO AT LEAST LOW-
END VFR CEILING BY LATE AFTERNOON. WILL CONTINUE THIS LOW-END VFR
THROUGH THE EVENING HOURS...BUT ITS WORTH NOTING THAT THE LATEST
NAM/MET GUIDANCE ACTUALLY RE-ESTABLISHES A SOLID MVFR DECK AFTER
SUNSET...SO THIS TREND WILL BEAR WATCHING. WIND-WISE...A STEADY
NORTH-NORTHWEST BREEZE WILL PREVAIL...WITH GUST POTENTIAL OF
18-22KT THROUGH LATE AFTERNOON BEFORE SLACKENING SOMEWHAT DURING
THE EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...SAR
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
730 AM EDT WED MAY 22 2013
.SYNOPSIS...
MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY.
A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS
AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY
PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A
SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT
LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED
THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T
BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED
WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN
ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH
THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY
THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 722 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE
NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS
DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT
SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT
GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES
DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION
EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE
MESOSCALE COLD POOL HAS BEEN ESTABLISHED.
WILL SEE PATCHY FOG ACROSS THE REGION THRU 13Z GIVEN SATURATED
LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW
ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS
MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU
EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS
ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. CLOUDS BUT NO PCPN
THRU MID AFTN...WILL TREND SKY COVER FROM OVC TO BKN BY NOONTIME.
THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB
FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT
REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC
ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL
VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z
NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT
NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT
MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A
BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING
LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE
DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND
DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY
WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE
AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS
SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW
VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL
ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS
AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME
SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE
SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD
WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE
VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF
WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION
CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY
SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD
SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE
OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE
EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S
DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW
TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S.
THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND
ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD
ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS
WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN
ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF
LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN
PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+"
RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES
INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE
OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY
FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION
BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF
SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES.
FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN
SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME
PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD.
COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE
HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH
DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE
00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE
MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS
CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS
WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND
SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A
CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC
STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF
MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM
AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH
AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE
DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO
500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO
DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE
ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR
SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH
EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES
TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO
DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45
KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35
MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY
IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A
RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS.
SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO
TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF
SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN
THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...IFR CIGS AT MSS/PBG/SLK WL SLOWLY IMPROVE TO
MVFR/VFR BY 15Z THIS MORNING. CIGS WL BE THE SLOWEST TO IMPROVE AT
MSS DUE TO A LIGHT NE DRAINAGE FLW DOWN THE SLV. EXPECT SOME
CLRING BTWN 15Z-18Z TODAY WITH VFR CONDITIONS...BEFORE MORE
SHOWERS/STORMS DEVELOP BY 21Z. A SFC BOUNDARY CONTS TO BE DRAPED
ACRS OUR TAF SITES AND WL BE THE FOCUS FOR PRECIP. THIS
FRNT...COMBINED WITH SFC HEATING/INSTABILITY WL PRODUCE MORE
SCATTERED/NUMEROUS SHOWERS/STORMS LATE THIS AFTN THRU THIS
EVENING. MVFR TO BRIEF PERIODS OF IFR CIGS/VIS LIKELY IN THE
HEAVIER STORMS. IN ADDITION...BRIEF GUSTY WINDS WL BE POSSIBLE.
THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH AREAS OF LOW CLOUDS
AND PATCHY FOG LIKELY DEVELOPING BY 06Z THURSDAY...ESPECIALLY
MSS/SLK/MPV.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY... UNSETTLED WX WITH OCCASIONAL
SHOWERS/STORMS WL CONT FOR THURSDAY INTO FRIDAY ACRS OUR TAF
SITES. THE STRONGER SHOWERS/STORMS ON THURS AFTN/EVENING
ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR CONDITIONS...WITH
BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS WL HAVE THE
POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS OF FOG
AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME
LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO
SATURDAY/SUNDAY WITH MVFR...BEFORE HIGH PRES SLOWLY BUILDS INTO THE
REGION BY EARLY NEXT WK. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER
THE WEEKEND...WITH AREAS OF LLVL TURBULENCE.
&&
.HYDROLOGY...
430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY
HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST
24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND
TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE
AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND
EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE
BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL
RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR
DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY
OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM
RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE
SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER
THURSDAY AND THURSDAY NIGHT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
723 AM EDT WED MAY 22 2013
.SYNOPSIS...
MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY.
A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS
AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY
PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A
SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT
LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED
THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T
BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED
WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN
ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH
THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY
THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 722 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE
NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS
DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT
SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT
GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES
DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION
EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE
MESOSCALE COLD POOL HAS BEEN ESTABLISHED.
WILL SEE PATCHY FOG ACROSS THE REGION THRU 13Z GIVEN SATURATED
LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW
ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS
MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU
EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS
ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. CLOUDS BUT NO PCPN
THRU MID AFTN...WILL TREND SKY COVER FROM OVC TO BKN BY NOONTIME.
THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB
FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT
REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC
ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL
VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z
NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT
NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT
MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A
BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING
LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE
DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND
DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY
WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE
AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS
SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW
VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL
ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS
AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME
SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE
SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD
WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE
VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF
WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION
CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY
SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD
SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE
OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE
EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S
DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW
TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S.
THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND
ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD
ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS
WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN
ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF
LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN
PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+"
RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES
INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE
OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY
FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION
BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF
SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES.
FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN
SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME
PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD.
COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE
HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH
DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE
00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE
MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS
CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS
WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND
SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A
CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC
STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF
MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM
AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH
AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE
DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO
500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO
DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE
ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR
SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH
EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES
TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO
DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45
KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35
MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY
IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A
RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS.
SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO
TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF
SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN
THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION
FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING.
CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT
BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN
ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY
07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS
DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING.
MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT
FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD
MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT
MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE
DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC
HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS
SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR
CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY
WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH
AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z
THURSDAY...ESPECIALLY MSS/SLK/MPV.
OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY
INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON
THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR
CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS
WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS
OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME
LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY
SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION
BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE
WEEKEND...WITH AREAS OF LLVL TURBULENCE.
&&
.HYDROLOGY...
430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY
HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST
24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND
TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE
AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND
EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE
BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL
RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR
DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY
OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM
RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE
SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER
THURSDAY AND THURSDAY NIGHT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1015 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN
CAROLINAS THROUGH THURSDAY. SHOWERS AND THUNDERSTORMS WILL INCREASE
THURSDAY AND THURSDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. THE
FRONT WILL CROSS THE REGION FRIDAY MORNING. A MUCH COOLER AND DRIER
AIRMASS WILL FOLLOW...COMPLEMENTS OF A CANADIAN HIGH PRESSURE...AND
AFFECT THE AREA THIS WEEKEND. THE HIGH WILL SLIDE OFF THE EAST COAST
EARLY NEXT WEEK WITH TEMPERATURES REBOUNDING TO NEAR NORMAL...ALONG
WITH AN INCREASE IN AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 AM WEDNESDAY...FIRST SHOWERS OF THE DAY JUST STARTING
TO POP OVER THE COASTAL COUNTIES. NO SIGNIFICANT CHANGES ARE
NEEDED TO THE FORECAST EARLY THIS MORNING. EARLIER DISCUSSION FROM
3:00 AM FOLLOWS:
THE WEAK UPPER LEVEL SHEAR AXIS THAT HAS BEEN NEARLY STATIONARY
ACROSS THE EASTERN CAROLINAS FOR THE PAST TWO DAYS HAS DECAYED AS
LIGHT SOUTHERLY FLOW HAS ESTABLISHED ITSELF THROUGHOUT THE 500-700
MB LAYER. ALTHOUGH THE OVERALL AIRMASS REMAINS THE SAME AS
YESTERDAY...TRIGGERS FOR TODAY`S CONVECTION WILL BE SURFACE
BOUNDARIES ONLY. EARLY MORNING CONVECTION MOVING ONSHORE ACROSS OAK
ISLAND THROUGH WILMINGTON IS ASSOCIATED WITH A LOW-LEVEL CONVERGENCE
AXIS WHERE SOUTHWEST WINDS ACROSS THE SC COASTAL WATERS CONVERGE
WITH SOUTH WINDS CLOSER TO THE GULF STREAM. THIS CONVECTIVE ACTIVITY
SHOULD BECOME MORE ISOLATED IN NATURE TOWARD DAYBREAK...BUT THE
REMNANT CONVERGENCE AXIS MAY BECOME ACTIVE AGAIN BY LATE MORNING AS
THE DEVELOPING SEABREEZE CIRCULATION CREATES ADDITIONAL CONVERGENCE
IN THE LOW LEVELS.
BY EARLY AFTERNOON WE SHOULD HAVE A DEVELOPING FIELD OF SCATTERED
SHOWERS ACROSS MOST OF THE AREA EAST OF I-95 AND WEST OF THE
BEACHES. AS THE SEABREEZE MAKES GOOD PROGRESS INLAND THIS AFTERNOON
EXPECT CLEARING CONDITIONS WITHIN 20 MILES OF THE COAST...BUT
SHOWER AND T-STORM CHANCES WILL INCREASE TO 30-40 PERCENT WEST OF
THE SEABREEZE BOUNDARY IN A MODERATELY UNSTABLE AND COMPLETELY
UNCAPPED AIRMASS. 850 MB TEMPS IN THE +15C TO +17C RANGE WILL
SUPPORT TEMPERATURES IN THE MID 80S INLAND TODAY...WITH LOWER 80S
CLOSER TO THE COAST.
SOUTHWESTERLY WINDS WILL INCREASE ABOVE THE SURFACE TONIGHT AS A
MID-LATITUDE STORM SYSTEM SWEEPS EAST INTO THE GREAT LAKES. A WEAK
VORTICITY MAXIMUM LOCATED ACROSS GEORGIA THIS EVENING WILL MOVE
EASTWARD AND SHOULD SUSTAIN ISOLATED TO SCATTERED SHOWER AND T-STORM
POTENTIAL THROUGH THE NIGHT ACROSS THE EASTERN CAROLINAS. WHILE THE
SC PEE DEE REGION WILL BE THE CLOSEST GEOGRAPHICALLY TO THE INCOMING
VORT ALOFT...PRECIP CHANCES MAY ACTUALLY BECOME GREATEST IN THE
WILMINGTON AREA AS MODELS ARE INSISTENT THAT A BLOB OF GULF STREAM
CONVECTION WILL MOVE NORTH INTO THE CAPE FEAR REGION OVERNIGHT. LOWS
SHOULD FALL TO 66-70...WARMEST AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...THIS PERIOD WILL BE HIGHLIGHTED BY THE
EVOLUTION OF A RATHER DEEP MID-LEVEL TROF THAT WILL DOMINATE THE
WEATHER ACROSS THE FA BY THE END OF THIS PERIOD. AT THE BEGINNING OF
THE SHORT TERM...THE AMPLIFYING UPPER TROF IS PROGGED TO BE JUST
EAST OF THE MISSISSIPPI RIVER...AND BY LATE FRIDAY NIGHT ITS NORTH
TO SOUTH TROF AXIS WILL HAVE MOVED JUST OFF THE NORTH AND SOUTH
CAROLINA COASTS...VIA NAM AND GFS MODELS. MODELS AT TIMES HAVE TRIED
TO MAKE THIS AN AMPLIFIED FULL LATITUDE TROF BUT INDIVIDUAL
VORTS/IMPULSES ROTATING THROUGH THIS UPPER FEATURE...ARE PROGGED TO
MOVE AT DIFFERENT SPEEDS AND THUS PREVENTING THE CARVING OF A TRUE
FULL LATITUDE TROF. ONE OF THE STRONGER VORTS IS PROGGED TO TRACK
ACROSS THE FA FRIDAY AFTERNOON/EVENING AS DYNAMICS FROM THIS FEATURE
AND COLDER TEMPS ALOFT PROVIDE ENOUGH INSTABILITY FOR ISOLATED
CONVECTION.
AT THE SURFACE...WESTERN ATLANTIC RIDGING WILL CONTINUE ACROSS THE
FA EARLY THURSDAY. A PRE-FRONTAL OR LEE SIDE TROF ORIENTED N-S WILL
DEVELOP ACROSS THE WEST-CENTRAL CAROLINAS AND BECOME THE FOCUS FOR
CONVECTION DEVELOPMENT AS IT SLOWLY PROGRESSES EASTWARD. IN ADDITION
MID-DAY/AFTERNOON DIURNALLY INDUCED CONVECTION WILL BREAK OUT ACROSS
THE COASTAL PORTIONS OF THE ILM CWA. WILL INDICATE 50 POPS
INLAND...WITH 30-40 CLOSER TO THE COAST DURING THE DAY THURSDAY. FOR
THURSDAY NIGHT...THE APPROACHING COLD FRONT WILL BECOME THE PRIMARY
FORCE FOR INDUCING CONVECTION. HOWEVER...THE SUB-TROPICAL/TROPICAL
MOISTURE FEED WILL HAVE BEEN PUSHED OFFSHORE AND NO LONGER THE
PRIMARY SOURCE. THINKING IS THAT ENOUGH MOISTURE WILL REMAIN FOR
ADDITIONAL CONVECTION TO FIRE AHEAD OF THE COLD FRONT...DEPENDING
HOW MUCH THE ATM IS ABLE TO DE-STABILIZE FROM THE CONVECTION THAT
DEVELOPED EARLIER IN THE DAY. AS A RESULT...WILL HIGHLIGHT 40-50
POPS IN THE EVENING AND SLOWLY DROP THEM TO SLIGHT CHANCE OVERNIGHT.
MODELS AFTER MIDNIGHT FRIDAY...DIVERGE FROM ONE ANOTHER WITH RESPECT
TO THEIR SOLUTIONS RELATED TO THE TIMING AND PLACEMENT OF THE COLD
FRONT. FOR EXAMPLE THE NAM AND CANADIAN HAVE THE FRONT OFF THE
CAROLINA COASTS BY DAYBREAK FRI...WHEREAS THE GFS LAGS BEHIND AND
ONLY HAS IT PROGRESSING THROUGH THE COASTAL CAROLINAS BY DAYBREAK
FRI. WILL LEAN TOWARD THE SLIGHTLY SLOWER PROGRESSION OF THE CFP.
POST FRONTAL DRIER AIR FINALLY ADVECTS ACROSS THE FA DURING THE DAY
FRI. CANADIAN HIGH PRESSURE WILL FINALLY PROVIDE RELIEF FROM THE
HUMID SUBTROPICAL/TROPICAL AIR MASS THAT AFFECTED THE FA FOR MUCH OF
THIS WEEK.
AS FOR MAX/MIN TEMPS...A RANGE OF 80 TO 85 FOR HIGHS THU...SIMILAR
TO WHAT THE NAM/GFS MOS GUIDANCE SHOWS. THE COLD AIR ADVECTION
BEHIND THE CFP WILL LAG BEHIND...AND BE OFFSET BY A DOWNSLOPE
TRAJECTORY IN THE WIND FIELDS. AS A RESULT...HAVE GONE ABOVE
GUIDANCE FOR FRIDAYS HIGHS WITH THE COASTAL COUNTIES LIKELY TO BE
WARMER THAN INLAND. A COMPROMISED MOS GUIDANCE MIN FORECAST WAS
USED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...FOR SATURDAY THRU MONDAY MID LEVEL FEATURES
REMAIN RELATIVELY UNCHANGED WITH THE TROF AXIS ASSOCIATED WITH THE
UPPER TROF HAVING ONLY PROGRESSED JUST OFF THE EAST COAST. THE
CENTRAL U.S. WILL BE HIGHLIGHTED BY AN UPPER RIDGE WITH ITS AXIS
RUNNING N-S ALONG THE MISSISSIPPI RIVER. BY TUESDAY...THE EUROPEAN
FLATTENS THIS RIDGE WHEREAS THE GFS PROGRESSES IT EASTWARD AND
MAINTAINING ITS IDENTITY. PREFERRED THE GFS SOLUTION AT THIS POINT.
AT THE SFC...CANADIAN HIGH PRESSURE TO RIDGE ACROSS THE FA SATURDAY.
ITS CENTER IS PROGGED TO BREAK APART BY SUNDAY...WITH THE SOUTHERN
EXTENT OF ITS CENTER MOVING ACROSS AND OFFSHORE FROM THE CAROLINAS
MONDAY AND TUESDAY. SUBSIDENCE ALOFT WILL KEEP A LID ON THE
DIURNALLY DRIVEN CU FROM DEVELOPING IN THE VERTICAL. THEREFORE NO
POPS THROUGH SUNDAY. FOR LATE SUNDAY NIGHT THRU TUESDAY...MODELS ARE
HINTING AT A BACK-DOOR COLD FRONT DROPPING SOUTHWARD...AND BECOMING
STATIONARY JUST NORTH OF THE FA. THIS MAY BECOME AN AID TO POSSIBLE
MCS/MCC THAT DEVELOP WELL UPSTREAM MON AND TUE...WHICH WILL FOLLOW
THE NW-SE UPPER FLOW. TOO FAR OUT IN TIME TO PREDICT THEIR
TIMING...HOWEVER ENOUGH OF A POSSIBILITY TO PLACE A LOW CHANCE POP
IN THE GOING FORECAST.
FOR THIS UPCOMING MEMORIAL DAY WEEKEND...SATURDAY THROUGH MONDAY
MORNING TEMPS ACROSS THE FA WILL RUN 5 TO 10 DEGREES BELOW
NORMAL...ESPECIALLY WITH OVERNIGHT LOWS. FOR MONDAY THRU
TUESDAY...WILL BE LOOKING AT NEAR NORMAL TEMPS. IF THE BACK-DOOR
COLD FRONT DROPS FURTHER SOUTH THAN ANTICIPATED...THE NW FLOW AHEAD
OF IT COULD PUSH TEMPS WELL INTO THE 80S TO AROUND 90...MUCH HIGHER
THAN THE CURRENT MOS GUIDANCE.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...A BIT LESS DEEP MOISTURE TODAY WITH MAINLY SOUTHERLY
FLOW. A LOW LCL INDICATES A MVFR CEILING COULD FORM AN HOUR OR SO
AFTER SUNRISE. HRRR MODEL INDICATES AN EARLY START TO CONVECTION
ALONG THE SEA BREEZE TODAY...WITH SHOWERS LIKELY NOT AS STRONG DUE
TO LACK OF MOISTURE. MOST OF THE ACTIVITY WILL ACTUALLY BE BETWEEN
THE INLAND AND COASTAL TERMINALS...NEARING THE INLAND TERMINALS BY
18Z. SOUTHERLY FLOW WILL BE A BIT GUSTY THIS AFTERNOON...DIMINISHING
DIURNALLY THIS EVENING. WILL REEVALUATE BACK END OF TAFS ON THE NEXT
MODEL RUN AS ANOTHER SLUG OF MOISTURE ADVECTS IN FROM THE SOUTH.
EXTENDED OUTLOOK...SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY
FRIDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM WEDNESDAY...LATEST OBS SHOW LIGHT SOUTH WINDS WITH
SEAS IN THE 3 TO 4 FT RANGE. NO SIGNIFICANT CHANGES ARE NEEDED TO
THE FORECAST. EARLIER DISCUSSION FROM 3:00 AM FOLLOWS:
BERMUDA HIGH PRESSURE WILL MOVE LITTLE THROUGH TONIGHT...CONTINUING
TO PUMP AIR FROM THE CARIBBEAN NORTHWARD ACROSS THE CAROLINA COASTAL
WATERS. LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES...TOO FAR
AWAY FOR ANY DIRECT AFFECTS JUST YET. A TYPICAL SUMMER/TROPICAL
WEATHER REGIME IS EXPECTED WITH SCATTERED SHOWERS AND THUNDERSTORMS
OVER THE COASTAL WATERS ENDING THIS MORNING...THEN REDEVELOPING
TONIGHT. MODELS ARE ACTUALLY QUITE INSISTENT THAT AT LEAST ONE
CONCENTRATED BATCH OF CONVECTION COULD ROLL IN OFF THE GULF STREAM
OVERNIGHT AND TOWARD COASTAL NORTH CAROLINA.
OUTSIDE OF ANY SHOWER AND THUNDERSTORM ACTIVITY...SOUTH WINDS SHOULD
AVERAGE 10-15 KNOTS WITH 3-4 FT SEAS. DOMINANT WAVE PERIODS AT THE
FRYING PAN SHOALS BUOY ARE 6 SECONDS...WITH YESTERDAY`S 10 SECOND
EASTERLY SWELL HARDLY REGISTERING ANYMORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WESTERN ATLANTIC RIDGING WILL PROVIDE A
RATHER SOLID 15 KT SOUTHERLY FLOW DURING THU...BECOMING SW LATE
THU AFTERNOON AND NIGHT. THE SFC PG WILL TIGHTEN BETWEEN THE
APPROACHING COLD FRONT AND THE WESTERN ATLANTIC HIGH CENTERED WELL
OFFSHORE FROM THE SE U.S.COAST. COULD SEE 15 TO 20 KT WITH SOME
HIGHER GUSTS. CFP SLATED FOR AFTER DAYBREAK FRI...WITH WINDS
VEERING TO W TO NW 10 TO 15 KT...INCREASING TO 15 TO 25 KT FRIDAY
NIGHT DUE TO COLD AIR ADVECTION COMBINED WITH A TIGHTENED SFC PG.
SIGNIFICANT SEAS WILL RANGE FROM 2 TO 4 FT THU...BUILDING TO 3 TO
5 FT LATE THU THROUGH EARLY FRI. TEMPORARILY DROPPING BACK TO 2 TO
4 FT DURING FRIDAY...THEN BUILDING BACK TO 3 TO 5 FT FRI NIGHT
WITH 6 FOOTERS POSSIBLE OUTER WATERS OFF CAPE FEAR. SIG. SEAS WILL
PRIMARILY BE DRIVEN BY AN ESE GROUND SWELL AT 8 TO 9 SECOND
PERIODS DURING EARLY THU...WITH 4 TO 6 SECOND PERIOD WIND DRIVEN
WAVES TO DOMINATE LATE THU THRU FRI NITE. SCEC CONDITIONS POSSIBLE
FOR ALL WATERS...WITH A BORDERLINE SCA FOR THE ILM NC WATERS
DURING THE INFLUX OF COLD AIR FRI NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...POSSIBLE SCEC OR SCA CONDITIONS WILL
PEAK DURING EARLY SATURDAY...WITH A DIMINISHING AND SUBSIDING
TREND FOR WINDS AND SIGNIFICANT SEAS RESPECTIVELY DURING THE
LATTER 2/3RDS OF THIS PERIOD. ALL IN RESPONSE TO THE CENTER OF THE
MODERATING CANADIAN HIGH PUSHING ACROSS THE LOCAL WATERS SUNDAY
THROUGH SUNDAY NIGHT. WINDS ARE PROGGED TO BECOME VARIABLE IN
DIRECTION DURING SUNDAY AND SUNDAY NIGHT AT 10 KT OR LESS.
SIGNIFICANT SEAS WILL BE DRIVEN BY LOCALLY PRODUCED SHORT PERIOD
WIND DRIVEN WAVES ON SATURDAY...WITH AN 8 TO 9 SECOND PERIOD SMALL
EASTERLY SWELL DOMINATING ON SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...REK/TRA
SHORT TERM...DCH
LONG TERM...DCH
AVIATION...TRA/SGL
MARINE...DCH/REK/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
703 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN
CAROLINAS THROUGH THURSDAY. SHOWERS AND THUNDERSTORMS WILL INCREASE
THURSDAY AND THURSDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. THE
FRONT WILL CROSS THE REGION FRIDAY MORNING. A MUCH COOLER AND DRIER
AIRMASS WILL FOLLOW...COMPLEMENTS OF A CANADIAN HIGH PRESSURE...AND
AFFECT THE AREA THIS WEEKEND. THE HIGH WILL SLIDE OFF THE EAST COAST
EARLY NEXT WEEK WITH TEMPERATURES REBOUNDING TO NEAR NORMAL...ALONG
WITH AN INCREASE IN AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM WEDNESDAY...EARLIER SHOWER ACTIVITY OFFSHORE AND OVER
WILMINGTON DISSIPATED A COUPLE HOURS AGO. THE ATMOSPHERE REMAINS
SUPPORTIVE OF AT LEAST SHALLOW CONVECTION...BUT CERTAINLY WITH LESS
COVERAGE THAN WHAT WAS EXPERIENCED YESTERDAY GIVEN DRIER AIR ALOFT
AND SUBSEQUENT LOWER PRECIPITABLE WATER VALUES. THIS WILL REDUCE
PRECIPITATION EFFICIENCY AND SHOULD LEAD TO LOWER RAINFALL TOTALS
EVEN WHERE IT DOES RAIN. NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST EARLY THIS MORNING. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
THE WEAK UPPER LEVEL SHEAR AXIS THAT HAS BEEN NEARLY STATIONARY
ACROSS THE EASTERN CAROLINAS FOR THE PAST TWO DAYS HAS DECAYED AS
LIGHT SOUTHERLY FLOW HAS ESTABLISHED ITSELF THROUGHOUT THE 500-700
MB LAYER. ALTHOUGH THE OVERALL AIRMASS REMAINS THE SAME AS
YESTERDAY...TRIGGERS FOR TODAY`S CONVECTION WILL BE SURFACE
BOUNDARIES ONLY. EARLY MORNING CONVECTION MOVING ONSHORE ACROSS OAK
ISLAND THROUGH WILMINGTON IS ASSOCIATED WITH A LOW-LEVEL CONVERGENCE
AXIS WHERE SOUTHWEST WINDS ACROSS THE SC COASTAL WATERS CONVERGE
WITH SOUTH WINDS CLOSER TO THE GULF STREAM. THIS CONVECTIVE ACTIVITY
SHOULD BECOME MORE ISOLATED IN NATURE TOWARD DAYBREAK...BUT THE
REMNANT CONVERGENCE AXIS MAY BECOME ACTIVE AGAIN BY LATE MORNING AS
THE DEVELOPING SEABREEZE CIRCULATION CREATES ADDITIONAL CONVERGENCE
IN THE LOW LEVELS.
BY EARLY AFTERNOON WE SHOULD HAVE A DEVELOPING FIELD OF SCATTERED
SHOWERS ACROSS MOST OF THE AREA EAST OF I-95 AND WEST OF THE
BEACHES. AS THE SEABREEZE MAKES GOOD PROGRESS INLAND THIS AFTERNOON
EXPECT CLEARING CONDITIONS WITHIN 20 MILES OF THE COAST...BUT
SHOWER AND T-STORM CHANCES WILL INCREASE TO 30-40 PERCENT WEST OF
THE SEABREEZE BOUNDARY IN A MODERATELY UNSTABLE AND COMPLETELY
UNCAPPED AIRMASS. 850 MB TEMPS IN THE +15C TO +17C RANGE WILL
SUPPORT TEMPERATURES IN THE MID 80S INLAND TODAY...WITH LOWER 80S
CLOSER TO THE COAST.
SOUTHWESTERLY WINDS WILL INCREASE ABOVE THE SURFACE TONIGHT AS A
MID-LATITUDE STORM SYSTEM SWEEPS EAST INTO THE GREAT LAKES. A WEAK
VORTICITY MAXIMUM LOCATED ACROSS GEORGIA THIS EVENING WILL MOVE
EASTWARD AND SHOULD SUSTAIN ISOLATED TO SCATTERED SHOWER AND T-STORM
POTENTIAL THROUGH THE NIGHT ACROSS THE EASTERN CAROLINAS. WHILE THE
SC PEE DEE REGION WILL BE THE CLOSEST GEOGRAPHICALLY TO THE INCOMING
VORT ALOFT...PRECIP CHANCES MAY ACTUALLY BECOME GREATEST IN THE
WILMINGTON AREA AS MODELS ARE INSISTENT THAT A BLOB OF GULF STREAM
CONVECTION WILL MOVE NORTH INTO THE CAPE FEAR REGION OVERNIGHT. LOWS
SHOULD FALL TO 66-70...WARMEST AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...THIS PERIOD WILL BE HIGHLIGHTED BY THE
EVOLUTION OF A RATHER DEEP MID-LEVEL TROF THAT WILL DOMINATE THE
WEATHER ACROSS THE FA BY THE END OF THIS PERIOD. AT THE BEGINNING OF
THE SHORT TERM...THE AMPLIFYING UPPER TROF IS PROGGED TO BE JUST
EAST OF THE MISSISSIPPI RIVER...AND BY LATE FRIDAY NIGHT ITS NORTH
TO SOUTH TROF AXIS WILL HAVE MOVED JUST OFF THE NORTH AND SOUTH
CAROLINA COASTS...VIA NAM AND GFS MODELS. MODELS AT TIMES HAVE TRIED
TO MAKE THIS AN AMPLIFIED FULL LATITUDE TROF BUT INDIVIDUAL
VORTS/IMPULSES ROTATING THROUGH THIS UPPER FEATURE...ARE PROGGED TO
MOVE AT DIFFERENT SPEEDS AND THUS PREVENTING THE CARVING OF A TRUE
FULL LATITUDE TROF. ONE OF THE STRONGER VORTS IS PROGGED TO TRACK
ACROSS THE FA FRIDAY AFTERNOON/EVENING AS DYNAMICS FROM THIS FEATURE
AND COLDER TEMPS ALOFT PROVIDE ENOUGH INSTABILITY FOR ISOLATED
CONVECTION.
AT THE SURFACE...WESTERN ATLANTIC RIDGING WILL CONTINUE ACROSS THE
FA EARLY THURSDAY. A PRE-FRONTAL OR LEE SIDE TROF ORIENTED N-S WILL
DEVELOP ACROSS THE WEST-CENTRAL CAROLINAS AND BECOME THE FOCUS FOR
CONVECTION DEVELOPMENT AS IT SLOWLY PROGRESSES EASTWARD. IN ADDITION
MID-DAY/AFTERNOON DIURNALLY INDUCED CONVECTION WILL BREAK OUT ACROSS
THE COASTAL PORTIONS OF THE ILM CWA. WILL INDICATE 50 POPS
INLAND...WITH 30-40 CLOSER TO THE COAST DURING THE DAY THURSDAY. FOR
THURSDAY NIGHT...THE APPROACHING COLD FRONT WILL BECOME THE PRIMARY
FORCE FOR INDUCING CONVECTION. HOWEVER...THE SUB-TROPICAL/TROPICAL
MOISTURE FEED WILL HAVE BEEN PUSHED OFFSHORE AND NO LONGER THE
PRIMARY SOURCE. THINKING IS THAT ENOUGH MOISTURE WILL REMAIN FOR
ADDITIONAL CONVECTION TO FIRE AHEAD OF THE COLD FRONT...DEPENDING
HOW MUCH THE ATM IS ABLE TO DE-STABILIZE FROM THE CONVECTION THAT
DEVELOPED EARLIER IN THE DAY. AS A RESULT...WILL HIGHLIGHT 40-50
POPS IN THE EVENING AND SLOWLY DROP THEM TO SLIGHT CHANCE OVERNIGHT.
MODELS AFTER MIDNIGHT FRIDAY...DIVERGE FROM ONE ANOTHER WITH RESPECT
TO THEIR SOLUTIONS RELATED TO THE TIMING AND PLACEMENT OF THE COLD
FRONT. FOR EXAMPLE THE NAM AND CANADIAN HAVE THE FRONT OFF THE
CAROLINA COASTS BY DAYBREAK FRI...WHEREAS THE GFS LAGS BEHIND AND
ONLY HAS IT PROGRESSING THROUGH THE COASTAL CAROLINAS BY DAYBREAK
FRI. WILL LEAN TOWARD THE SLIGHTLY SLOWER PROGRESSION OF THE CFP.
POST FRONTAL DRIER AIR FINALLY ADVECTS ACROSS THE FA DURING THE DAY
FRI. CANADIAN HIGH PRESSURE WILL FINALLY PROVIDE RELIEF FROM THE
HUMID SUBTROPICAL/TROPICAL AIR MASS THAT AFFECTED THE FA FOR MUCH OF
THIS WEEK.
AS FOR MAX/MIN TEMPS...A RANGE OF 80 TO 85 FOR HIGHS THU...SIMILAR
TO WHAT THE NAM/GFS MOS GUIDANCE SHOWS. THE COLD AIR ADVECTION
BEHIND THE CFP WILL LAG BEHIND...AND BE OFFSET BY A DOWNSLOPE
TRAJECTORY IN THE WIND FIELDS. AS A RESULT...HAVE GONE ABOVE
GUIDANCE FOR FRIDAYS HIGHS WITH THE COASTAL COUNTIES LIKELY TO BE
WARMER THAN INLAND. A COMPROMISED MOS GUIDANCE MIN FORECAST WAS
USED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...FOR SATURDAY THRU MONDAY MID LEVEL FEATURES
REMAIN RELATIVELY UNCHANGED WITH THE TROF AXIS ASSOCIATED WITH THE
UPPER TROF HAVING ONLY PROGRESSED JUST OFF THE EAST COAST. THE
CENTRAL U.S. WILL BE HIGHLIGHTED BY AN UPPER RIDGE WITH ITS AXIS
RUNNING N-S ALONG THE MISSISSIPPI RIVER. BY TUESDAY...THE EUROPEAN
FLATTENS THIS RIDGE WHEREAS THE GFS PROGRESSES IT EASTWARD AND
MAINTAINING ITS IDENTITY. PREFERRED THE GFS SOLUTION AT THIS POINT.
AT THE SFC...CANADIAN HIGH PRESSURE TO RIDGE ACROSS THE FA SATURDAY.
ITS CENTER IS PROGGED TO BREAK APART BY SUNDAY...WITH THE SOUTHERN
EXTENT OF ITS CENTER MOVING ACROSS AND OFFSHORE FROM THE CAROLINAS
MONDAY AND TUESDAY. SUBSIDENCE ALOFT WILL KEEP A LID ON THE
DIURNALLY DRIVEN CU FROM DEVELOPING IN THE VERTICAL. THEREFORE NO
POPS THROUGH SUNDAY. FOR LATE SUNDAY NIGHT THRU TUESDAY...MODELS ARE
HINTING AT A BACK-DOOR COLD FRONT DROPPING SOUTHWARD...AND BECOMING
STATIONARY JUST NORTH OF THE FA. THIS MAY BECOME AN AID TO POSSIBLE
MCS/MCC THAT DEVELOP WELL UPSTREAM MON AND TUE...WHICH WILL FOLLOW
THE NW-SE UPPER FLOW. TOO FAR OUT IN TIME TO PREDICT THEIR
TIMING...HOWEVER ENOUGH OF A POSSIBILITY TO PLACE A LOW CHANCE POP
IN THE GOING FORECAST.
FOR THIS UPCOMING MEMORIAL DAY WEEKEND...SATURDAY THROUGH MONDAY
MORNING TEMPS ACROSS THE FA WILL RUN 5 TO 10 DEGREES BELOW
NORMAL...ESPECIALLY WITH OVERNIGHT LOWS. FOR MONDAY THRU
TUESDAY...WILL BE LOOKING AT NEAR NORMAL TEMPS. IF THE BACK-DOOR
COLD FRONT DROPS FURTHER SOUTH THAN ANTICIPATED...THE NW FLOW AHEAD
OF IT COULD PUSH TEMPS WELL INTO THE 80S TO AROUND 90...MUCH HIGHER
THAN THE CURRENT MOS GUIDANCE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...A BIT LESS DEEP MOISTURE TODAY WITH MAINLY SOUTHERLY
FLOW. A LOW LCL INDICATES A MVFR CEILING COULD FORM AN HOUR OR SO
AFTER SUNRISE. HRRR MODEL INDICATES AN EARLY START TO CONVECTION
ALONG THE SEA BREEZE TODAY...WITH SHOWERS LIKELY NOT AS STRONG DUE
TO LACK OF MOISTURE. MOST OF THE ACTIVITY WILL ACTUALLY BE BETWEEN
THE INLAND AND COASTAL TERMINALS...NEARING THE INLAND TERMINALS BY
18Z. SOUTHERLY FLOW WILL BE A BIT GUSTY THIS AFTERNOON...DIMINISHING
DIURNALLY THIS EVENING. WILL REEVALUATE BACK END OF TAFS ON THE NEXT
MODEL RUN AS ANOTHER SLUG OF MOISTURE ADVECTS IN FROM THE SOUTH.
EXTENDED OUTLOOK...SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY
FRIDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM WEDNESDAY...ISOLATED SHOWERS MAY CONTINUE THROUGH THE
MORNING HOURS BUT SHOULD DISSIPATE WITH THE AFTERNOON SEABREEZE
CIRCULATION. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
BERMUDA HIGH PRESSURE WILL MOVE LITTLE THROUGH TONIGHT...CONTINUING
TO PUMP AIR FROM THE CARIBBEAN NORTHWARD ACROSS THE CAROLINA COASTAL
WATERS. LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES...TOO FAR
AWAY FOR ANY DIRECT AFFECTS JUST YET. A TYPICAL SUMMER/TROPICAL
WEATHER REGIME IS EXPECTED WITH SCATTERED SHOWERS AND THUNDERSTORMS
OVER THE COASTAL WATERS ENDING THIS MORNING...THEN REDEVELOPING
TONIGHT. MODELS ARE ACTUALLY QUITE INSISTENT THAT AT LEAST ONE
CONCENTRATED BATCH OF CONVECTION COULD ROLL IN OFF THE GULF STREAM
OVERNIGHT AND TOWARD COASTAL NORTH CAROLINA.
OUTSIDE OF ANY SHOWER AND THUNDERSTORM ACTIVITY...SOUTH WINDS SHOULD
AVERAGE 10-15 KNOTS WITH 3-4 FT SEAS. DOMINANT WAVE PERIODS AT THE
FRYING PAN SHOALS BUOY ARE 6 SECONDS...WITH YESTERDAY`S 10 SECOND
EASTERLY SWELL HARDLY REGISTERING ANYMORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WESTERN ATLANTIC RIDGING WILL PROVIDE A
RATHER SOLID 15 KT SOUTHERLY FLOW DURING THU...BECOMING SW LATE
THU AFTERNOON AND NIGHT. THE SFC PG WILL TIGHTEN BETWEEN THE
APPROACHING COLD FRONT AND THE WESTERN ATLANTIC HIGH CENTERED WELL
OFFSHORE FROM THE SE U.S.COAST. COULD SEE 15 TO 20 KT WITH SOME
HIGHER GUSTS. CFP SLATED FOR AFTER DAYBREAK FRI...WITH WINDS
VEERING TO W TO NW 10 TO 15 KT...INCREASING TO 15 TO 25 KT FRIDAY
NIGHT DUE TO COLD AIR ADVECTION COMBINED WITH A TIGHTENED SFC PG.
SIGNIFICANT SEAS WILL RANGE FROM 2 TO 4 FT THU...BUILDING TO 3 TO
5 FT LATE THU THROUGH EARLY FRI. TEMPORARILY DROPPING BACK TO 2 TO
4 FT DURING FRIDAY...THEN BUILDING BACK TO 3 TO 5 FT FRI NIGHT
WITH 6 FOOTERS POSSIBLE OUTER WATERS OFF CAPE FEAR. SIG. SEAS WILL
PRIMARILY BE DRIVEN BY AN ESE GROUND SWELL AT 8 TO 9 SECOND
PERIODS DURING EARLY THU...WITH 4 TO 6 SECOND PERIOD WIND DRIVEN
WAVES TO DOMINATE LATE THU THRU FRI NITE. SCEC CONDITIONS POSSIBLE
FOR ALL WATERS...WITH A BORDERLINE SCA FOR THE ILM NC WATERS
DURING THE INFLUX OF COLD AIR FRI NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...POSSIBLE SCEC OR SCA CONDITIONS WILL
PEAK DURING EARLY SATURDAY...WITH A DIMINISHING AND SUBSIDING
TREND FOR WINDS AND SIGNIFICANT SEAS RESPECTIVELY DURING THE
LATTER 2/3RDS OF THIS PERIOD. ALL IN RESPONSE TO THE CENTER OF THE
MODERATING CANADIAN HIGH PUSHING ACROSS THE LOCAL WATERS SUNDAY
THROUGH SUNDAY NIGHT. WINDS ARE PROGGED TO BECOME VARIABLE IN
DIRECTION DURING SUNDAY AND SUNDAY NIGHT AT 10 KT OR LESS.
SIGNIFICANT SEAS WILL BE DRIVEN BY LOCALLY PRODUCED SHORT PERIOD
WIND DRIVEN WAVES ON SATURDAY...WITH AN 8 TO 9 SECOND PERIOD SMALL
EASTERLY SWELL DOMINATING ON SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH/TRA
NEAR TERM...TRA
SHORT TERM...DCH
LONG TERM...DCH
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
650 AM EDT WED MAY 22 2013
.SYNOPSIS...
WESTERN ATLANTIC HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS
THE EASTERN CAROLINAS THROUGH EARLY THURSDAY. SHOWERS AND
THUNDERSTORMS WILL INCREASE THURSDAY AND THURSDAY NIGHT AHEAD OF
AN APPROACHING COLD FRONT. THE FRONT WILL CROSS THE REGION FRIDAY
MORNING. A MUCH COOLER AND DRIER AIR MASS WILL FOLLOW...COMPLEMENTS
OF A CANADIAN HIGH PRESSURE...AND AFFECT THE AREA THIS WEEKEND.
THE HIGH WILL SLIDE OFF THE EAST COAST EARLY NEXT WEEK WITH
TEMPERATURES REBOUNDING TO NEAR NORMAL...ALONG WITH AN INCREASE IN
DIURNALLY DRIVEN CONVECTION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...THE WEAK UPPER LEVEL SHEAR AXIS THAT HAS
BEEN NEARLY STATIONARY ACROSS THE EASTERN CAROLINAS FOR THE PAST TWO
DAYS HAS DECAYED AS LIGHT SOUTHERLY FLOW HAS ESTABLISHED ITSELF
THROUGHOUT THE 500-700 MB LAYER. ALTHOUGH THE OVERALL AIRMASS
REMAINS THE SAME AS YESTERDAY...TRIGGERS FOR TODAY`S CONVECTION WILL
BE SURFACE BOUNDARIES ONLY. EARLY MORNING CONVECTION MOVING ONSHORE
ACROSS OAK ISLAND THROUGH WILMINGTON IS ASSOCIATED WITH A LOW-LEVEL
CONVERGENCE AXIS WHERE SOUTHWEST WINDS ACROSS THE SC COASTAL WATERS
CONVERGE WITH SOUTH WINDS CLOSER TO THE GULF STREAM. THIS CONVECTIVE
ACTIVITY SHOULD BECOME MORE ISOLATED IN NATURE TOWARD DAYBREAK...BUT
THE REMNANT CONVERGENCE AXIS MAY BECOME ACTIVE AGAIN BY LATE
MORNING AS THE DEVELOPING SEABREEZE CIRCULATION CREATES ADDITIONAL
CONVERGENCE IN THE LOW LEVELS.
BY EARLY AFTERNOON WE SHOULD HAVE A DEVELOPING FIELD OF SCATTERED
SHOWERS ACROSS MOST OF THE AREA EAST OF I-95 AND WEST OF THE
BEACHES. AS THE SEABREEZE MAKES GOOD PROGRESS INLAND THIS AFTERNOON
EXPECT CLEARING CONDITIONS WITHIN 20 MILES OF THE COAST...BUT
SHOWER AND T-STORM CHANCES WILL INCREASE TO 30-40 PERCENT WEST OF
THE SEABREEZE BOUNDARY IN A MODERATELY UNSTABLE AND COMPLETELY
UNCAPPED AIRMASS. 850 MB TEMPS IN THE +15C TO +17C RANGE WILL
SUPPORT TEMPERATURES IN THE MID 80S INLAND TODAY...WITH LOWER 80S
CLOSER TO THE COAST.
SOUTHWESTERLY WINDS WILL INCREASE ABOVE THE SURFACE TONIGHT AS A
MID-LATITUDE STORM SYSTEM SWEEPS EAST INTO THE GREAT LAKES. A WEAK
VORTICITY MAXIMUM LOCATED ACROSS GEORGIA THIS EVENING WILL MOVE
EASTWARD AND SHOULD SUSTAIN ISOLATED TO SCATTERED SHOWER AND T-STORM
POTENTIAL THROUGH THE NIGHT ACROSS THE EASTERN CAROLINAS. WHILE THE
SC PEE DEE REGION WILL BE THE CLOSEST GEOGRAPHICALLY TO THE INCOMING
VORT ALOFT...PRECIP CHANCES MAY ACTUALLY BECOME GREATEST IN THE
WILMINGTON AREA AS MODELS ARE INSISTENT THAT A BLOB OF GULF STREAM
CONVECTION WILL MOVE NORTH INTO THE CAPE FEAR REGION OVERNIGHT. LOWS
SHOULD FALL TO 66-70...WARMEST AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...THIS PERIOD WILL BE HIGHLIGHTED BY THE
EVOLUTION OF A RATHER DEEP MID-LEVEL TROF THAT WILL DOMINATE THE
WEATHER ACROSS THE FA BY THE END OF THIS PERIOD. AT THE BEGINNING OF
THE SHORT TERM...THE AMPLIFYING UPPER TROF IS PROGGED TO BE JUST
EAST OF THE MISSISSIPPI RIVER...AND BY LATE FRIDAY NIGHT ITS NORTH
TO SOUTH TROF AXIS WILL HAVE MOVED JUST OFF THE NORTH AND SOUTH
CAROLINA COASTS...VIA NAM AND GFS MODELS. MODELS AT TIMES HAVE TRIED
TO MAKE THIS AN AMPLIFIED FULL LATITUDE TROF BUT INDIVIDUAL
VORTS/IMPULSES ROTATING THROUGH THIS UPPER FEATURE...ARE PROGGED TO
MOVE AT DIFFERENT SPEEDS AND THUS PREVENTING THE CARVING OF A TRUE
FULL LATITUDE TROF. ONE OF THE STRONGER VORTS IS PROGGED TO TRACK
ACROSS THE FA FRIDAY AFTERNOON/EVENING AS DYNAMICS FROM THIS FEATURE
AND COLDER TEMPS ALOFT PROVIDE ENOUGH INSTABILITY FOR ISOLATED
CONVECTION.
AT THE SURFACE...WESTERN ATLANTIC RIDGING WILL CONTINUE ACROSS THE
FA EARLY THURSDAY. A PRE-FRONTAL OR LEE SIDE TROF ORIENTED N-S WILL
DEVELOP ACROSS THE WEST-CENTRAL CAROLINAS AND BECOME THE FOCUS FOR
CONVECTION DEVELOPMENT AS IT SLOWLY PROGRESSES EASTWARD. IN ADDITION
...MID-DAY/AFTERNOON DIURNALLY INDUCED CONVECTION WILL BREAK OUT
ACROSS THE COASTAL PORTIONS OF THE ILM CWA. WILL INDICATE 50 POPS
INLAND...WITH 30-40 CLOSER TO THE COAST DURING THE DAY THURSDAY. FOR
THURSDAY NIGHT...THE APPROACHING COLD FRONT WILL BECOME THE PRIMARY
FORCE FOR INDUCING CONVECTION. HOWEVER...THE SUB-TROPICAL/TROPICAL
MOISTURE FEED WILL HAVE BEEN PUSHED OFFSHORE AND NO LONGER THE
PRIMARY SOURCE. THINKING IS THAT ENOUGH MOISTURE WILL REMAIN FOR
ADDITIONAL CONVECTION TO FIRE AHEAD OF THE COLD FRONT...DEPENDING
HOW MUCH THE ATM IS ABLE TO DE-STABILIZE FROM THE CONVECTION THAT
DEVELOPED EARLIER IN THE DAY. AS A RESULT...WILL HIGHLIGHT 40-50
POPS IN THE EVENING AND SLOWLY DROP THEM TO SLIGHT CHANCE OVERNIGHT.
MODELS AFTER MIDNIGHT FRIDAY...DIVERGE FROM ONE ANOTHER WITH RESPECT
TO THEIR SOLUTIONS RELATED TO THE TIMING AND PLACEMENT OF THE COLD
FRONT. FOR EXAMPLE THE NAM AND CANADIAN HAVE THE FRONT OFF THE
CAROLINA COASTS BY DAYBREAK FRI...WHEREAS THE GFS LAGS BEHIND AND
ONLY HAS IT PROGRESSING THROUGH THE COASTAL CAROLINAS BY DAYBREAK
FRI. WILL LEAN TOWARD THE SLIGHTLY SLOWER PROGRESSION OF THE CFP.
POST FRONTAL DRIER AIR FINALLY ADVECTS ACROSS THE FA DURING THE DAY
FRI. CANADIAN HIGH PRESSURE WILL FINALLY PROVIDE RELIEF FROM THE
HUMID SUBTROPICAL/TROPICAL AIR MASS THAT AFFECTED THE FA FOR MUCH OF
THIS WEEK.
AS FOR MAX/MIN TEMPS...A RANGE OF 80 TO 85 FOR HIGHS THU...SIMILAR
TO WHAT THE NAM/GFS MOS GUIDANCE SHOWS. THE COLD AIR ADVECTION
BEHIND THE CFP WILL LAG BEHIND...AND BE OFFSET BY A DOWNSLOPE
TRAJECTORY IN THE WIND FIELDS. AS A RESULT...HAVE GONE ABOVE
GUIDANCE FOR FRIDAYS HIGHS WITH THE COASTAL COUNTIES LIKELY TO BE
WARMER THAN INLAND. A COMPROMISED MOS GUIDANCE MIN FORECAST WAS
USED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...FOR SATURDAY THRU MONDAY MID LEVEL FEATURES
REMAIN RELATIVELY UNCHANGED WITH THE TROF AXIS ASSOCIATED WITH THE
UPPER TROF HAVING ONLY PROGRESSED JUST OFF THE EAST COAST. THE
CENTRAL U.S. WILL BE HIGHLIGHTED BY AN UPPER RIDGE WITH ITS AXIS
RUNNING N-S ALONG THE MISSISSIPPI RIVER. BY TUESDAY...THE EUROPEAN
FLATTENS THIS RIDGE WHEREAS THE GFS PROGRESSES IT EASTWARD AND
MAINTAINING ITS IDENTITY. PREFERRED THE GFS SOLUTION AT THIS POINT.
AT THE SFC...CANADIAN HIGH PRESSURE TO RIDGE ACROSS THE FA SATURDAY.
ITS CENTER IS PROGGED TO BREAK APART BY SUNDAY...WITH THE SOUTHERN
EXTENT OF ITS CENTER MOVING ACROSS AND OFFSHORE FROM THE CAROLINAS
MONDAY AND TUESDAY. SUBSIDENCE ALOFT WILL KEEP A LID ON THE
DIURNALLY DRIVEN CU FROM DEVELOPING IN THE VERTICAL. THEREFORE NO
POPS THROUGH SUNDAY. FOR LATE SUNDAY NIGHT THRU TUESDAY...MODELS ARE
HINTING AT A BACK-DOOR COLD FRONT DROPPING SOUTHWARD...AND BECOMING
STATIONARY JUST NORTH OF THE FA. THIS MAY BECOME AN AID TO POSSIBLE
MCS/MCC THAT DEVELOP WELL UPSTREAM MON AND TUE...WHICH WILL FOLLOW
THE NW-SE UPPER FLOW. TOO FAR OUT IN TIME TO PREDICT THEIR
TIMING...HOWEVER ENOUGH OF A POSSIBILITY TO PLACE A LOW CHANCE POP
IN THE GOING FORECAST.
FOR THIS UPCOMING MEMORIAL DAY WEEKEND...SATURDAY THROUGH MONDAY
MORNING TEMPS ACROSS THE FA WILL RUN 5 TO 10 DEGREES BELOW
NORMAL...ESPECIALLY WITH OVERNIGHT LOWS. FOR MONDAY THRU
TUESDAY...WILL BE LOOKING AT NEAR NORMAL TEMPS. IF THE BACK-DOOR
COLD FRONT DROPS FURTHER SOUTH THAN ANTICIPATED...THE NW FLOW AHEAD
OF IT COULD PUSH TEMPS WELL INTO THE 80S TO AROUND 90...MUCH HIGHER
THAN THE CURRENT MOS GUIDANCE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...A BIT LESS DEEP MOISTURE TODAY WITH MAINLY SOUTHERLY
FLOW. A LOW LCL INDICATES A MVFR CEILING COULD FORM AN HOUR OR SO
AFTER SUNRISE. HRRR MODEL INDICATES AN EARLY START TO CONVECTION
ALONG THE SEA BREEZE TODAY...WITH SHOWERS LIKELY NOT AS STRONG DUE
TO LACK OF MOISTURE. MOST OF THE ACTIVITY WILL ACTUALLY BE BETWEEN
THE INLAND AND COASTAL TERMINALS...NEARING THE INLAND TERMINALS BY
18Z. SOUTHERLY FLOW WILL BE A BIT GUSTY THIS AFTERNOON...DIMINISHING
DIURNALLY THIS EVENING. WILL REEVALUATE BACK END OF TAFS ON THE NEXT
MODEL RUN AS ANOTHER SLUG OF MOISTURE ADVECTS IN FROM THE SOUTH.
EXTENDED OUTLOOK...SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY
FRIDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...BERMUDA HIGH PRESSURE WILL MOVE LITTLE
THROUGH TONIGHT...CONTINUING TO PUMP AIR FROM THE CARIBBEAN
NORTHWARD ACROSS THE CAROLINA COASTAL WATERS. LOW PRESSURE WILL MOVE
EAST ACROSS THE GREAT LAKES...TOO FAR AWAY FOR ANY DIRECT AFFECTS
JUST YET. A TYPICAL SUMMER/TROPICAL WEATHER REGIME IS EXPECTED WITH
SCATTERED SHOWERS AND THUNDERSTORMS OVER THE COASTAL WATERS ENDING
THIS MORNING...THEN REDEVELOPING TONIGHT. MODELS ARE ACTUALLY QUITE
INSISTENT THAT AT LEAST ONE CONCENTRATED BATCH OF CONVECTION COULD
ROLL IN OFF THE GULF STREAM OVERNIGHT AND TOWARD COASTAL NORTH
CAROLINA.
OUTSIDE OF ANY SHOWER AND THUNDERSTORM ACTIVITY...SOUTH WINDS SHOULD
AVERAGE 10-15 KNOTS WITH 3-4 FT SEAS. DOMINANT WAVE PERIODS AT THE
FRYING PAN SHOALS BUOY ARE 6 SECONDS...WITH YESTERDAY`S 10 SECOND
EASTERLY SWELL HARDLY REGISTERING ANYMORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WESTERN ATLANTIC RIDGING WILL PROVIDE A
RATHER SOLID 15 KT SOUTHERLY FLOW DURING THU...BECOMING SW LATE
THU AFTERNOON AND NIGHT. THE SFC PG WILL TIGHTEN BETWEEN THE
APPROACHING COLD FRONT AND THE WESTERN ATLANTIC HIGH CENTERED WELL
OFFSHORE FROM THE SE U.S.COAST. COULD SEE 15 TO 20 KT WITH SOME
HIGHER GUSTS. CFP SLATED FOR AFTER DAYBREAK FRI...WITH WINDS
VEERING TO W TO NW 10 TO 15 KT...INCREASING TO 15 TO 25 KT FRIDAY
NIGHT DUE TO COLD AIR ADVECTION COMBINED WITH A TIGHTENED SFC PG.
SIGNIFICANT SEAS WILL RANGE FROM 2 TO 4 FT THU...BUILDING TO 3 TO
5 FT LATE THU THROUGH EARLY FRI. TEMPORARILY DROPPING BACK TO 2 TO
4 FT DURING FRIDAY...THEN BUILDING BACK TO 3 TO 5 FT FRI NIGHT
WITH 6 FOOTERS POSSIBLE OUTER WATERS OFF CAPE FEAR. SIG. SEAS WILL
PRIMARILY BE DRIVEN BY AN ESE GROUND SWELL AT 8 TO 9 SECOND
PERIODS DURING EARLY THU...WITH 4 TO 6 SECOND PERIOD WIND DRIVEN
WAVES TO DOMINATE LATE THU THRU FRI NITE. SCEC CONDITIONS POSSIBLE
FOR ALL WATERS...WITH A BORDERLINE SCA FOR THE ILM NC WATERS
DURING THE INFLUX OF COLD AIR FRI NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...POSSIBLE SCEC OR SCA CONDITIONS WILL
PEAK DURING EARLY SATURDAY...WITH A DIMINISHING AND SUBSIDING
TREND FOR WINDS AND SIGNIFICANT SEAS RESPECTIVELY DURING THE
LATTER 2/3RDS OF THIS PERIOD. ALL IN RESPONSE TO THE CENTER OF THE
MODERATING CANADIAN HIGH PUSHING ACROSS THE LOCAL WATERS SUNDAY
THROUGH SUNDAY NIGHT. WINDS ARE PROGGED TO BECOME VARIABLE IN
DIRECTION DURING SUNDAY AND SUNDAY NIGHT AT 10 KT OR LESS.
SIGNIFICANT SEAS WILL BE DRIVEN BY LOCALLY PRODUCED SHORT PERIOD
WIND DRIVEN WAVES ON SATURDAY...WITH AN 8 TO 9 SECOND PERIOD SMALL
EASTERLY SWELL DOMINATING ON SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...TRA
SHORT TERM...DCH
LONG TERM...DCH
AVIATION...43
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1025 AM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 1024 AM CDT WED MAY 22 2013
NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE AS THE INHERITED
FORECAST IS ON TRACK AND BLENDED TO 15 UTC OBSERVED TRENDS. GIVEN
RADAR AND SURFACE OBSERVATIONS...DID INCREASE POPS TO NEAR 100
FOR THIS MORNING ACROSS LAKES COUNTRY...DECREASING THROUGH THE
AFTERNOON WITH THE CWA EXPECTED TO BE PRECIPITATION FREE BY 22-00
UTC. THE RAP HAS PERFORMED WELL IN REGARDS TO THE STRATUS SHIELD
THE PAST COUPLE OF DAYS AND FOLLOWED ITS LATEST 14 UTC SOLUTION
FOR CLOUD COVER.
UPDATE ISSUED AT 647 AM CDT WED MAY 22 2013
NORTH TO NORTHEASTERLY WINDS PICKING UP HAVE SCOURED OUT THE FOG
THAT WAS STARTING TO FORM OVER OUR NORTHWESTERN COUNTIES...SO
REMOVED MENTION FOR THE REST OF THE MORNING. RAIN WILL LINGER OVER
THE SOUTHEASTERN COUNTIES FOR A WHILE LONGER THIS MORNING BEFORE
DRYING OUT THIS AFTERNOON. CLOUDS WILL DECREASE THROUGHOUT THE
DAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 330 AM CDT WED MAY 22 2013
UPPER LOW FINALLY BEGINNING TO PULL AWAY FROM THE CWA AS IT WILL
SLOWLY MOVE SOUTHEASTWARD INTO IA TODAY. SFC HIGH PRESSURE HAS
STARTED TO NOSE DOWN OUT OF CANADA INTO THE NORTHERN PLAINS. MOST
OF THE PRECIP HAS MOVED SOUTH OF THE AREA ALTHOUGH A FEW SCATTERED
SHOWERS STILL LINGER IN THE SOUTHERN COUNTIES. THE NORTH HAS
CLEARED OUT COMPLETELY AND THERE HAS BEEN SOME PATCHY FOG
FORMATION AROUND CANDO AND LANGDON. HOWEVER...THERE IS STILL A
PRESSURE GRADIENT AND THINK THIS WILL KEEP FOG FROM BECOMING
WIDESPREAD AND DENSE. WILL KEEP A CLOSE EYE ON OBS THROUGH THE
EARLY MORNING HOURS.
SHOWERS AND CLOUDS WILL LINGER OVER THE SOUTHERN COUNTIES FOR MUCH
OF THE DAY BEFORE FINALLY CLEARING OUT BY LATE AFTERNOON. THIS
WILL KEEP TEMPS COOLER AND AROUND 60 WHILE THE NORTH WILL BE A BIT
WARMER. THE SFC HIGH WILL MOVE FURTHER DOWN FROM CANADA INTO THE
UPPER MS VALLEY TONIGHT. THIS SHOULD HELP THE NORTHER TIER ALONG WITH
EASTERN COUNTIES GET DOWN TO BELOW 40 DEGREES IN SOME AREAS.
THURSDAY SHOULD BE QUIET AND A BIT WARMER AS UPPER RIDGING BUILDS
OVER THE REGION. WITH SOME DECENT SUNSHINE KEPT HIGHS IN THE 60S
TO LOW 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM CDT WED MAY 22 2013
THURSDAY NIGHT SOUTHEASTERLY WINDS STILL START PICKING UP OVER THE
WESTERN COUNTIES AS SFC HIGH PRESSURE OVER MN/WI ALONG WITH A
DEVELOPING LOW OVER MT CREATES A DECENT PRESSURE GRADIENT. THE
WINDS WILL HELP KEEP THE WESTERN COUNTIES FROM COMPLETELY
DECOUPLING AND STAY A BIT WARMER WHILE THE EAST WILL AGAIN DROP TO
AROUND 40 DEGREES. SOUTHEASTERLY WINDS WILL CONTINUE INTO FRIDAY
AND FRIDAY NIGHT AS A LEE TROUGH CONTINUES OVER THE WESTERN
PLAINS. MODELS ARE ALL IN FAIRLY DECENT AGREEMENT ON A WEAK
SHORTWAVE COMING OVER THE UPPER RIDGE AND SOME DECENT ISENTROPIC
LIFT PRODUCING SOME PRECIP FRIDAY AFTERNOON INTO FRIDAY NIGHT. AT
THIS POINT THE INSTABILITY SEEMS FAIRLY WEAK WITH SFC BASED CAPE
STAYING WEST OF OUR AREA AND ONLY A LITTLE BIT OF ELEVATED CAPE TO
WORK WITH. INCLUDED A CHANCE OF SHOWERS WITH ISOLATED
THUNDERSTORMS THROUGH FRIDAY NIGHT WITH BEST CHANCES IN OUR WEST.
SATURDAY-TUESDAY...00Z MODELS CONTINUE TO SUGGEST THE SYNOPTIC
PATTERN WILL BE DOMINATED BY LONGWAVE TROUGHING OVER THE WESTERN
US...WITH SOME DEGREE OF MID/UPPER LEVEL RIDGING INTO THE PLAINS
DURING MUCH OF THIS PERIOD. A SERIES OF WEAK UPPER LEVEL SHORTWAVE
TROUGHS EJECTING OUT OF THE BROADER TROUGH TO THE WEST WILL LEAD TO
BOUTS OF SHOWERS OR THUNDERSTORMS ACROSS THE REGION WITHIN THE LOW
TO MID-LEVEL WARM AIR ADVECTION ZONE ASSOCIATED WITH THE INDIVIDUAL
WAVES. WITH THIS TYPE OF PATTERN...CONFIDENCE IN THE
TIMING/PLACEMENT OF INDIVIDUAL WAVES IS LOW...SO CONTINUED TO CARRY
SOME POPS FOR MUCH OF THE PERIOD...ALTHOUGH MANY DRY HOURS ARE
EXPECTED.
THE 00Z GFS/ECMWF SUGGEST A TREND TO A MORE PREDOMINANT ACTIVE
SOUTHWEST FLOW PATTERN ACROSS THE PLAINS TOWARDS THE MIDDLE OF NEXT
WEEK...ALTHOUGH THE GFS IS MORE AMPLIFIED. THE GFS/ECMWF 925 MB
TEMPS RISE TO NEAR 20C ON TUESDAY...SUPPORTING HIGH TEMPS RISING
FROM MAINLY THE 60S OVER THE WEEKEND INTO THE 70S BY MONDAY OR
TUESDAY...WITH LOWS PRIMARILY IN THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 1024 AM CDT WED MAY 22 2013
THE EDGE OF THE MVFR STRATUS FIELD WITH EMBEDDED LIGHT RAIN WAS
JUST OVER THE KBJI AND KFAR TERMINALS...WITH VFR CONDITIONS
EXPECTED BY 16-17 UTC. OTHERWISE VFR CONDITIONS ARE EXPECTED FOR
KDVL...KGFK AND KTVF FOR THE 12 UTC TAFS. WILL CONTINUE TO MONITOR
STRATUS ACROSS WESTERN ONTARIO AND EASTERN MANITOBA PUSHING
SOUTHEAST. HOWEVER....THE STRATUS IS EXPECTED TO DISSOLVE THROUGH
THE DAY BEFORE REACHING NORTH DAKOTA. NORTHEAST WIND GUSTS OF
20-25 KTS WILL BE COMMON AT ALL TAF SITES LATE THIS MORNING AND
AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 650 PM CDT TUE MAY 21 2013
RAIN SHOWERS WILL BE ON THE WANE FROM THIS EVENING THROUGH WEDNESDAY
ALLOWING RIVER FORECASTING TO BE MORE RUNOFF AS OPPOSED TO QPF
BASED. RIVER FLOOD WARNINGS REMAIN IN EFFECT AT WALHALLA AND NECHE
ALONG THE PEMBINA RIVER WITH WALHALLA HAVING CRESTED EARLIER.
BIGGEST FORECAST CHANGE IS ALONG PARK RIVER AT GRAFTON WHERE THE
COPIOUS RAINFALL HAS TRIGGERED RAPID STAGE RISES TOWARD MAJOR AND
ULTIMATELY NEAR RECORD FLOOD LEVELS.
RIVER FLOOD WARNINGS ARE NOW IN EFFECT FOR MOST OF THE MAINSTEM RED
AS WELL AS THE SOUTHERN VALLEY MINNESOTA TRIBUTARIES TO THE RED.
THESE POINTS ARE ALL EXPECTED TO ACHIEVE MINOR FLOOD STAGE SAVE FOR
OSLO WHERE MODERATE FLOODING IS FORECAST.
AREAL FLOOD WARNINGS WILL BE IN EFFECT FOR PEMBINA...EASTERN
CAVALIER...AND WALSH COUNTIES THROUGH THURSDAY. BY THEN AREAL
FLOODING SHOULD BECOME LESS OF A CONCERN WITH A DEARTH OF
PRECIPITATION AND THE CHANCE FOR SOME DRYING WITH WARMER
TEMPERATURES.
THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR PARTS OF PEMBINA COUNTY
AS HEAVY RAINFALL OVER THE PAST FEW DAYS HAS CAUSED FLOOD WATERS TO
APPROACH THE TOP OF THE SPILLWAY AT THE RENWICK DAM. WATER
REMAINS VERY HIGH AND IS BEING HELD BACK BY A CONSTRUCTED EARTHEN
LEVEE ON TOP OF THE DAM STRUCTURE. OFFICIALS CONTINUE TO MONITOR
THE DAM AND THE NEW CLAY LEVEE FOR ANY EROSION. THERE ARE SEVERAL
OLD RETENTION DAMS TO THE WEST OF THE RENWICK DAM...AND WITH THE
LARGE AMOUNT OF WATER IN THE AREA THESE DAMS COULD FAIL. IF ONE OF
THESE OLDER DAMS TO THE WEST DID FAIL...THE TEMPORARY LEVEE ON TOP
OF THE RENWICK DAM WOULD NO LONGER BE ABLE TO HOLD BACK
WATER...AND FLOODING WOULD BE IMMINENT FOR THE CITIES OF
AKRA...CAVALIER...AND BATHGATE. THE PEMBINA COUNTY EMERGENCY
MANAGEMENT ANTICIPATES A POSSIBLE BREACH WITHIN THE NEXT 12
HOURS...AND HAVE ORDERED A MANDATORY EVACUATION FOR THE AREA
IMMEDIATELY DOWNSTREAM OF THE RENWICK DAM...INCLUDING THE CITY OF
CAVALIER.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...AYD
HYDROLOGY...WJB/TG/JH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1012 AM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 1006 AM CDT WED MAY 22 2013
MADE ONLY MINOR ADJUSTMENTS TO THE CURRENT FORECAST. THE 22.12Z
NAM AND LATEST RAP STILL SUGGEST A SMALL CHANCE FOR A SHOWER IN
THE FAR SOUTHEAST CORNER OF THE FORECAST AREA TODAY. DID NOT
INCREASE RAIN CHANCES IN THAT AREA FOR THE UPDATE...BUT WILL HAVE
TO KEEP AN EYE ON RADAR TRENDS IN CASE A STRAY SHOWER TRIES TO
MOVE IN LATER.
CLOUDS CONTINUE TO CLEAR FROM NORTH TO SOUTH...WITH THE MOST
ABUNDANT CLOUD COVER IN THE SOUTHERN JAMES RIVER VALLEY AS OF MID
MORNING. ADJUSTED NEAR TERM SKY COVER GRIDS TO REFLECT THE
TRENDS...WITH THE FORECAST FOR THIS AFTERNOON STILL ON TRACK.
UPDATE ISSUED AT 641 AM CDT WED MAY 22 2013
SURFACE HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION THIS
MORNING. ENOUGH GRADIENT FLOW HAS DEVELOPED TO MIX OUT MORNING FOG
ACROSS THE NORTHERN PORTIONS OF THE STATE. AS OF THE 11Z
OBS...THERE WAS NO FOG REPORTED ACROSS THE NORTHERN CWA. AS A
RESULT...REMOVED MORNING FOG WORDING FROM THE GRIDS AND ZONES.
FURTHERMORE...REGIONAL RADARS ARE NOT DETECTING ANY SHOWER
ACTIVITY ACROSS THE SOUTHERN CWA. LOWERED MORNING POPS AS A
RESULT. OTHERWISE...ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS
BASED ON CURRENT OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS
HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT WED MAY 22 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE DRY AND COOL
WEATHER IN THE WAKE OF THE STORM SYSTEM WHICH BROUGHT WIDESPREAD
HEAVY RAINFALL TO MUCH OF WEST AND CENTRAL NORTH DAKOTA THE PAST
SEVERAL DAYS.
CURRENTLY...MOSTLY CLEAR CONDITIONS ACROSS NORTHERN NORTH DAKOTA
WITH HIGH PRESSURE SLOWLY BUILDING SOUTH INTO THE NORTHERN PLAINS.
SCATTERED LIGHT RAIN CONTINUES TO ADVECT WEST-SOUTHWEST FURTHER
SOUTH...STILL UNDER THE INFLUENCE OF THE CLOSED UPPER LOW WHICH IS
MOVING SLOWLY SOUTH AND EAST INTO THE MID/UPPER MISSISSIPPI VALLEY
REGION. PRECIPITATION CHANCES WILL CONTINUE TO DIMINISH FROM NORTH
TO SOUTH AS THE LOW MOVES OUT OF THE REGION...AND SKIES WILL
CONTINUE TO CLEAR FROM NORTH TO SOUTH NOW THROUGH 15Z. WILL MAINTAIN
MORNING FOG NORTH WITH T/TD SPREADS NEARING ZERO AS SKIES
CLEAR...AND SEVERAL OBSERVING SITES REPORTING FOG. WILL MONITOR FOR
POSSIBLE DENSE FOG...HOWEVER WINDS ARE EXPECTED TO INCREASE SHORTLY
AFTER SUNRISE SO DO NOT EXPECT THE DURATION OF THE FOG TO BE VERY
LONG.
THE RIDGE CONTINUES TO BUILD SLOWLY SOUTH ACROSS THE CENTRAL
DAKOTAS TODAY...WITH GENERALLY SUNNY SKIES AND HIGHS IN THE 60S. THE
LATEST 00Z GFS/ECMWF DO GENERATE 100-200 J/KG OF MUCAPE THIS
AFTERNOON/EARLY EVENING ALONG A COLD FRONT PUSHING SOUTH ACROSS
SOUTHERN MANITOBA INTO NORTHEASTERN NORTH DAKOTA. FOR NOW WILL LEAVE
THINGS DRY...BUT COULD SEE A SHOWER OR TWO AROUND THE TURTLE
MOUNTAINS/DEVILS LAKE BASIN AREA.
ANOTHER COOL NIGHT WEDNESDAY THANKS TO CLEAR SKIES...LIGHT
WINDS...AND SFC DEWPOINTS RANGING FROM 35-45. THIS SHOULD RESULT IN
LOW TEMPERATURES AROUND 40 TO 45. SOUTHEAST RETURN FLOW INCREASES
LATE TONIGHT FAR WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 343 AM CDT WED MAY 22 2013
DRY CONDITIONS ARE EXPECTED THURSDAY AS MID/UPPER LEVEL RIDGING
DEVELOPS OVER THE PLAINS. GRADIENT FLOW WILL INCREASE WEST IN
RESPONSE TO AN UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST. WIND
ADVISORY CONDITIONS WILL BE POSSIBLE OVER SOUTHWESTERN NORTH DAKOTA
THURSDAY AFTERNOON/EVENING.
THE MEDIUM RANGE MODELS PROG THE FIRST IMPULSE TO EJECT FROM OF THE
AFOREMENTIONED PACIFIC NORTHWEST LOW OVER WESTERN AND CENTRAL NORTH
DAKOTA FRIDAY. THIS WILL LEAD TO THUNDERSTORM CHANCES DEVELOPING
AREAWIDE BY FRIDAY AFTERNOON.
AN UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH THE END OF THE
PERIOD. PERSISTENT SOUTHWESTERLY FLOW ALOFT COMBINED WITH GULF OF
MEXICO MOISTURE TAP WILL LEAD TO CHANCES FOR THUNDERSTORMS EACH DAY
THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. THE PERSISTENT
RETURN FLOW SHOULD ALSO ALLOW FOR A GRADUAL WARMING TREND TO DEVELOP
SATURDAY AND CONTINUE THROUGH THE END OF THE PERIOD. BY
TUESDAY...HIGHS SHOULD GENERALLY BE IN THE MID 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 641 AM CDT WED MAY 22 2013
VFR CIGS ALL TERMINALS THROUGH THE 12Z TAF PERIOD. EARLY MORNING FOG
POSSIBLE AT KMOT-KISN THROUGH 14Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...NH
LONG TERM...TM
AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
640 AM EDT WED MAY 22 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A
COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY
TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER
AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS
INTO THE OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A SOMEWHAT-DISORGANIZED SURFACE LOW IS CURRENTLY LOCATED IN IOWA
AND NORTHERN ILLINOIS. THIS LOW WILL SLOWLY MOVE TO THE EAST
TODAY...STRENGTHENING SLIGHTLY AS IT CROSSES THE SOUTHERN GREAT
LAKES. SOUTH OF THE LOW...A WEAK COLD FRONT WILL MOVE INTO THE ILN
CWA BY EVENING. THIS FRONT IS TOUGH TO PICK OUT ON SURFACE
TEMPERATURE FIELDS...BUT IS A BIT MORE EVIDENT WHEN EXAMINING
THETA-E SLIGHTLY ALOFT...AND ALSO LOOKING FOR SLIGHT WIND SHIFT
FROM SSW TO WSW. AT THE SAME TIME...A CLOSED UPPER LOW OVER THE
NORTHERN MISSISSIPPI VALLEY WILL BEGIN ITS MOVE TO THE EAST...WITH
A SHORTWAVE ROTATING NORTHEAST THROUGH INDIANA AND MICHIGAN. IN
THE RIGHT ENTRANCE REGION OF AN UPPER JET...THE SETUP OVER OHIO
WILL BE FAVORABLE FOR LARGE-SCALE LIFT.
THE STANDARD SUITE OF MODELS (GFS/NAM/CMC/ECMWF) HAS THUS FAR
APPEARED MUCH TOO AGGRESSIVE WITH THE OVERNIGHT PRECIPITATION
FORECAST OVER ILLINOIS AND INDIANA. THIS IS ADMITTEDLY A REGION
WHERE LIFT IS FORECAST TO CONTINUE TO ENHANCE THROUGH MORNING...IN
A REGION OF FALLING HEIGHTS AND A 30-40 KNOT LLJ. DEWPOINTS NORTH
OF THE CURRENT TENNESSEE CONVECTION ARE ABOUT 3-6 DEGREES LOWER THAN
IN THE SOUTHERN STATES...BUT THE AIR MASS COULD NOT BE DESCRIBED
AS PARTICULARLY DRY. AS WAS THE CASE YESTERDAY...THE HRRR HAS THE
CLOSEST APPROXIMATION TO THE CURRENT ACTIVITY. SEVERAL OTHER
CONVECTIVE-ALLOWING MODELS DEPICT QUITE A BIT OF CONVECTION MOVING
INTO THE ILN CWA AS EARLY AS 12Z...WHICH DOES NOT APPEAR REALISTIC
GIVEN THE LACK OF INSTABILITY AND CURRENT RADAR TRENDS. THE
OVERALL CHANCES FOR RAIN IN THE ILN CWA DO NOT APPEAR PARTICULARLY
HIGH THROUGH THE MORNING HOURS...THOUGH SLIGHTLY MORE SO IN THE
WESTERN PART OF THE CWA.
THE MAIN CONCERN FOR THE FORECAST TODAY IS THE POTENTIAL FOR
SEVERE WEATHER THIS AFTERNOON. GIVEN THE WIDE VARIANCE IN THE
HANDLING OF THE CURRENT WEATHER SITUATION...AND THE FACT THAT
THESE MESOSCALE FEATURES WILL BE VERY IMPORTANT IN CONVECTIVE
FORECASTING FOR THIS AFTERNOON...IT IS TOUGH TO TRUST ANY OF THE
SPECIFIC QPF/SIM-RADAR DEPICTIONS FOR THE AFTERNOON HOURS.
TO BEGIN WITH THE BIGGEST LIMITING FACTOR FOR TODAY...INSTABILITY
WILL BE IN QUESTION. GIVEN THE EXPECTED CLOUD COVER...AND EVEN
PRECIPITATION IN SOME PLACES...THE SURFACE TEMP FORECAST IS ON THE
LOW SIDE OF GUIDANCE. GIVEN THE THERMAL PROFILE...MLCAPE WILL
STRUGGLE TO REACH 1000 J/KG...WITH THE MOST INSTABILITY FORECAST
TO BE IN THE SOUTHEASTERN PARTS OF THE CWA. IN THE
NORTHWEST...WHERE TEMPS WILL BE THE COOLEST...INSTABILITY WILL BE
EVEN LESS (500 J/KG OR SO). SOUNDINGS ARE RELATIVELY MOIST THROUGH
THEIR DEPTH...WITH RATHER LOW LCL HEIGHTS (AROUND 2000-3000 FEET
AGL) FORECAST ON THE GFS/NAM (THE RAP13 APPEARS A BIT DRIER).
BECAUSE OF THE MOIST CONDITIONS...THE CAPE PROFILE IS NARROW.
UNLIKE YESTERDAY...THE OVERALL FORCING ENVIRONMENT WILL BE MORE
FAVORABLE FOR CONVECTIVE DEVELOPMENT...EVEN IF INSTABILITY IS
WEAK. WIND SHEAR IS ALSO SOMEWHAT OF A STRENGTH FOR
TODAY...ALTHOUGH MODEL-TO-MODEL ASSESSMENT ON SHEAR VALUES IS NOT
IN AS GOOD OF CONSENSUS AS IS USUALLY THE CASE. MOST OF THE SHEAR
WILL BE FAIRLY UNIDIRECTIONAL (ALL IN THE TOP-RIGHT QUADRANT OF
THE HODOGRAPH)...BUT WITH A DECENT CHANGE IN SPEED. 30-40 KNOTS OF
DEEP LAYER SHEAR WILL BE PRESENT...WITH 15-25 KNOTS IN THE 0-1KM
LAYER. 0-3KM SRH VALUES WILL GET INTO THE 100-200 RANGE...SO THERE
WILL CERTAINLY BE SOME POTENTIAL FOR ROTATING STORMS. THIS COULD
BE ENHANCED BY BOUNDARY INTERACTIONS OR AREAS OF BACKING SURFACE
WINDS (PERHAPS FURTHER NORTH AND CLOSER TO THE SURFACE LOW).
THE LACK OF INSTABILITY...ESPECIALLY IN THE HAIL GROWTH
ZONE...WILL LIMIT THE POTENTIAL FOR LARGE HAIL (PERHAPS OUTSIDE OF
A STRONGER / ROTATING UPDRAFT). THE THREAT FOR STRONG WINDS AND
TORNADOES DOES APPEAR TO EXIST...BUT THE THERMODYNAMIC ENVIRONMENT
SEEMS TO LIMIT THIS FROM BEING A HIGHER-END SEVERE EVENT. A
CLOUDIER/GRUNGIER MORNING WOULD SUPPORT AN ISOLATED SEVERE THREAT
WITH CLUSTERS OF STORMS CAPABLE OF STRONG WINDS AND MAYBE A BIT OF
ROTATION. THE OUTSIDE SHOT FOR TODAY WOULD BE A GREATER DEAL OF
BOUNDARY LAYER DESTABILIZATION (BETWEEN INSOLATION AND MOISTURE
ADVECTION)...WHICH WOULD BRING A GREATER RISK OF ALL THE SEVERE
MODES COMING TO THE TABLE. HOWEVER...GIVEN ALL THE EVIDENCE...THIS
FORECAST WILL LEAN TOWARD THE FORMER SOLUTION. THE HWO WILL FOLLOW
SUIT WITH A RELATIVELY TYPICAL-SOUNDING SEVERE THREAT WORDING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE INITIAL COLD FRONT WILL BE CROSSING THE ILN CWA DURING THE
EVENING HOURS...PRODUCING A RELATIVELY SMALL CHANGE IN THE
TEMPERATURE AND WIND FIELDS. BEHIND THE FRONT...PRECIPITATION WILL
BECOME LESS LIKELY...ESPECIALLY IN THE SOUTH AND SOUTHWEST
PORTIONS OF THE CWA.
A SECONDARY TROUGH (BOTH ALOFT AND AT THE SURFACE) WILL BE
ROTATING SOUTHEAST THROUGH THE CWA ON THURSDAY. THIS WILL BRING A
RENEWED CHANCE OF PRECIPITATION...ESPECIALLY IN THE NORTHERN AND
EASTERN PARTS OF THE CWA. INSTABILITY WILL BE VERY WEAK...BUT JUST
ENOUGH FOR SOME RISK OF THUNDER. THE AIR MASS ALOFT WILL BE
INCREASINGLY COLD...HELPING TO LEAD TO THE POSSIBILITY OF
CONVECTIVE SHOWERS.
ALONG WITH THIS ACTIVITY WILL BE A SECONDARY COLD FRONT...MUCH
BETTER DEFINED THAN THE FIRST. A NNW WIND SHIFT WILL ALLOW FOR
COLD ADVECTION TO BEGIN ON THURSDAY (AND ESPECIALLY THURSDAY
NIGHT). AS A RESULT...THE MAX TEMP GRADIENT FOR THURSDAY IS
SOMEWHAT SHARP (ABOUT 10 DEGREES FROM SW TO NE) AND THURSDAY
NIGHT MIN TEMPS MAY GET INTO THE 30S IN THE NORTHERN PORTIONS OF
THE CWA.
WITH DRY HIGH PRESSURE IN PLACE FOR FRIDAY...RELATIVELY TRANQUIL
CONDITIONS ARE EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
DRY WEATHER SHOULD CONTINUE ON SATURDAY FOR MOST OF THE AREA
EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A DEVELOPING FRONTAL
BOUNDARY MAY CAUSE A FEW SHOWERS.
FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO
LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF
SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH
NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER.
SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY
WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND
SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY
ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE
SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS
SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES
SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA
TONIGHT.
LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS STILL IN AN
INSTABILITY MINIMUM THIS MORNING. AS SUCH...THE LOW LEVEL JET
THAT IS OVER THE AREA MAY PRODUCE SOME SCATTERED SHOWERS THIS
MORNING.
FOR THIS AFTERNOON INTO THIS EVENING...THE PROSPECTS OF SHOWERS
AND THUNDERSTORMS WILL INCREASE AS DAYTIME HEATING INTERACTS WITH
LARGE SCALE SYNOPTIC LIFT. BEST CHANCE FOR WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL BE FROM MID AFTERNOON INTO THE EVENING HOURS.
HAVE PLACED THIS IN THE TAFS WITH A PREDOMINANT MVFR -SHRA AND A
VCTS/CB. AS STORMS BECOME MORE APPARENT AND CAN BE TRACKED ON
RADAR...TAFS WILL BE FINED TUNED ACCORDINGLY. WITH A MOIST
AIRMASS...SOME LOCAL MVFR CIGS AND IFR VSBYS WILL BE POSSIBLE IN
THUNDERSTORMS. DAYTIME HEATING/MIXING WILL PRODUCE SOUTH/SOUTHWEST
WINDS OF 12-16 KNOTS WITH GUSTS UP TO 30 KNOTS.
FOR TONIGHT...THE COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE
REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY.
HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS
AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT.
HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE
BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A
REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL REMAIN. IT IS UNCLEAR
AT THIS TIME IF MVFR CEILINGS WILL DEVELOP BEHIND THE FRONT SO
HAVE LEFT THEM AT VFR FOR NOW.
OUTLOOK...MVFR CONDITIONS POSSIBLE WITH SHOWERS AND EMBEDDED
THUNDERSTORMS THURSDAY INTO THURSDAY EVENING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1037 AM CDT WED MAY 22 2013
.UPDATE...
HAVE UPDATED THE FORECAST TO PROVIDE A LITTLE BETTER TIMING OF THE
EXPECTED CONVECTION THIS AFTN. REST OF THE FCST APPEARS IN GOOD
SHAPE.
MORNING UA ANALYSIS DEPICTS A SEASONALLY STRONG SOMEWHAT
NEGATIVELY TILTED MID LVL SHORT WAVE ACRS ARKANSAS APPROACHING THE
AREA. THE REGION IS ALSO ENTERING THE RR QUAD OF A RELATIVELY
STRONG UPPER LVL JET STREAK WHICH WILL ENHANCE LIFT THIS
AFTERNOON. THERMODYNAMICS DON`T LOOK ALL THAT IMPRESSIVE RIGHT NOW
AS THE ATMOS IS PRETTY WORKED OVER AND A FAIR AMOUNT OF DEBRIS
CLOUD HAS HUNG ARND. MORNING SOUNDING DEPICTS A DEEP DRY/CAPPED
LOWER ATMOSPHERE THAT IS INHIBITING ANY DEVELOPMENT. DO EXPECT A
LITTLE MORE SUN TO DEVELOP...AND A SLOW INCRS IN LLVL MSTR IS
STILL ANTICIPATED. THE COMBINATION OF COOLING MID LVL TEMPS AND A
WARMING/MOISTENING LOWER ATMOS WILL ALLOW CONVECTION TO INITIATE
MOST LIKELY RIGHT ALONG A COLD FRONT PROGGED TO CROSS THE AREA IN
THE MID/LATE AFTN. DECENT SPEED SHEAR IN PLACE SO EXPECT ACTIVITY
TO ORIENT IN A LINE WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE.
SPC CONTINUES A VERY LOW CHANCE OF A TORNADO AS WELL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
JOHNSTONE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
540 AM CDT WED MAY 22 2013
.UPDATE...
12Z TAF DISCUSSION.
&&
.AVIATION...
RADAR IMAGERY SHOWS MOST RECENT MCS HAS COLLAPSED WITH JUST A FEW
REMAINING -TSRA APPROACHING CSV. BY 12Z TAF ISSUANCE TIME...ALL
PRECIP SHOULD BE EAST OF AIRPORTS WITH DRY AND VFR CONDITIONS
EXPECTED THROUGH THE MORNING. LAMP GUIDANCE INDICATES GUSTY
SOUTHWEST WINDS TODAY WITH SPEEDS 5-12 KTS AND GUSTS TO 15-25
KTS. SHORTWAVE TROUGH ON WATER VAPOR IMAGERY OVER OKLAHOMA WILL
SWING ACROSS THE REGION LATER TODAY PRODUCING ANOTHER ROUND OF
SHOWERS AND STORMS IN THE AFTERNOON. DUE TO UNCERTAINTY ON
COVERAGE WILL ONLY MENTION VCTS AT CKV/BNA BUT TEMPO -TSRA AT
CSV. MUCH DRIER AIR ALOFT WILL FILTER IN BY 23/00Z WITH LESS
CLOUD COVER AND SOME PATCHY FOG POSSIBLE LATE IN TAF PERIOD.
55
&&
.PREV DISCUSSION... /ISSUED 246 AM CDT WED MAY 22 2013/
DISCUSSION...
CURRENT SETUP...UPPER TROUGH TAKING ON NEGATIVE TILT THROUGH THE MID-
LEVELS BASED ON LATEST RUC WITH THE COLDER AIR ALOFT REMAINING
BACK OVER CENTRAL PLAINS NOSING DOWN INTO ARKANSAS. A 35 TO 40
KNOT LOW LEVEL JET WAS CONTINUING TO FEED MOIST PLUME INTO MIDDLE
TENNESSEE. WIND FIELD LOOKS TO BE UNIDIRECTIONAL WITH SPEED SHEAR IN
THE LOWER TROPOSPHERE. UPPER LEVEL JET JUST RUNNING NORTH TO SOUTH
FROM ABOUT TEXARKANA NORTHWARD INTO IOWA WITH A 65 KNOT MID LEVEL
JET CUTTING ACROSS CENTRAL ARKANSAS. ON-GOING CONVECTION CURRENTLY
ACROSS FAR WESTERN KENTUCKY...WESTERN TENNESSEE AND DOWN THROUGH
MISSISSIPPI...BEEN SHOWING SIGNS OF WEAKENING LAST COUPLE OF HOURS
AS CLOUD TOPS CONTINUE TO WARM.
WITH THE CURRENT SETUP LOOKS LIKE SHOWERS AND STORMS WILL BE
LIKELY DURING THE DAY...WITH A FEW STRONG TO SEVERE STORMS
POSSIBLE...ESPECIALLY MID-DAY THROUGH THE AFTERNOON AND INTO THE
EARLY EVENING HOURS. THINK THE MAIN THREAT WILL BE DAMAGING WINDS AND
LARGE HAIL BUT ISOLATED TORNADOES ARE ALSO POSSIBLE. EVEN THOUGH
THE WIND FIELDS ARE UNIDIRECTIONAL THE SWEAT INDEX CLIMBS TO 362
AT 18Z AND 413 BY 00Z WITH MID-LEVEL DRYING IN PLACE DURING THE
MID-DAY THROUGH THE AFTERNOON/EARLY EVENING.
ON THURSDAY A SHORT WAVE ON THE BACK SIDE OF UPPER TROUGH WILL
DROP DOWN THROUGH THE OHIO VALLEY AND BRING A CHANCE FOR SHOWERS
AND ISOLATED THUNDERSTORMS MAINLY TO THE NORTHEAST HALF DURING THE
AFTERNOON WITH A SLIGHT CHANCE REMAINING ALONG THE PLATEAU
THURSDAY NIGHT. MUCH OF THE MEMORIAL DAY WEEKEND LOOKS DRY HOWEVER
MODELS HAVE BEEN DIFFERING. GFS HAS WARM FRONT DRAPED ACROSS THE
OHIO VALLEY THROUGH THE WEEKEND WHICH WOULD KEEP MID STATE
BASICALLY WARM AND DRY. THE EURO HAS WARM FRONT DRAPED THROUGH
WESTERN TENNESSEE INTO NORTHERN ALABAMA AND KEEPS SHOWERS AND
STORMS IN THE MID STATE JUST ABOUT EACH DAY THROUGH THE MEMORIAL
DAY WEEKEND. HAVE OPTED TO GO WITH GFS FOR THIS FORECAST PACKAGE.
HAVE BACKED OFF A TAD FROM MAV MOS ON HIGHS TODAY AND WENT CLOSER
TO THE MET DUE TO CLOUD COVER AND SHOWER/STORM CHANCES. STAYED
CLOSE TO MOS GUIDANCE THROUGH REMAINDER OF FORECAST.
BOYD
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
940 AM EDT WED MAY 22 2013
.SYNOPSIS...
A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO
THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT
THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EDT WEDNESDAY...
ADJUSTED POPS FOR LATEST RADAR TREND...SHAPING POPS THIS MORNING
INTO TOWARDS LATEST RNK WRFARW. KEPT THE BEST CHANCE FOR
THUNDERSTORMS THIS AFTERNOON IN THE WEST. SWODY1 HAS PLACED A
SLIGHT RISK JUST TO OUR WEST. MORNING RUN SHOWED THE POTENTIAL
FOR LINE OF CONVECTION REACHING THE WEST BETWEEN 00Z AND 06Z
TONIGHT. WILL REVIEW 12Z RUN BEFORE MAKING ANY MAJOR ADJUSTMENTS
FOR TONIGHT. MODIFIED TEMPERATURES AND DEW POINTS THIS MORNING
INTO THIS AFTERNOON. RAISED HIGH TEMPERATURES UP A FEW DEGREES IN
SOUTHEAST. UPDATED FIRE WEATHER GRIDS...FWFRNK OUT. ADDITIONAL
CHANGES LATER TODAY.
AS OF 340 AM EDT WEDNESDAY...
A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL
FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST
FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE
RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING
WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA.
HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION
THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE
ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE
CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE
AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS
AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING
NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL
CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON.
EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT
THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE
PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS
INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE
INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN
00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS
CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY
IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH
FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY
THIS EVENING TO COVER THIS POTENTIAL.
THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF
OUR REGION TODAY INTO TONIGHT.
CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT
AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS
TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID
80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID
60S SE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 AM EDT WEDNESDAY...
A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION
BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE
CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY.
OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT
THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE.
LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY
ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION
COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM
PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE
PIEDMONT AND TIDEWATER AREAS OF VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
FRIDAY NIGHT AND SATURDAY:
QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM
FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST
OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE
BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD
GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 AM EDT WEDNESDAY...
PATCHY FOG WILL DISSIPATE QUICKLY...ALTHOUGH IFR CIGS MAY LINGER
ACROSS THE PIEDMONT FROM DAN-LYH FOR A WHILE THIS MORNING.
OTHERWISE...MOSTLY VFR AFT 14Z WITH SC/CU DEVELOPING FROM EARLY
MORNING MOISTURE. MAIN CONCERN WILL COME LATE TODAY AS THE STRONG
COLD FRONT RESPONSIBLE FOR ALL OF THE SEVERE WEATHER IN THE
MIDWEST RECENTLY APPROACHES THE AREA FROM THE WEST. ECMWF/GFS
GENERALLY CONSISTENT ON A LINE OF STRONG THUNDERSTORMS MOVING
INTO FAR SW VA FROM KY/TN IN THE 00Z-04Z TIME FRAME...THEN
GENERALLY DISSIPATING AS IT MOVES TOWARD THE NEW RIVER VALLEY
REGION...SIMILAR TIMING TO WHAT WE SAW YESTERDAY...BUT EXPECT
ACTIVITY TO BE A LITTLE MORE POTENT THIS EVENING. DO NOT EXPECT
THIS ACTIVITY TO SURVIVE AS IT REACHES THE PIEDMONT.
HOWEVER...MODELS SHOW...ESPECIALLY THE GFS...POTENTIAL TSRA
DEVELOPMENT ACROSS THE NC PIEDMONT...LIFTING NORTHWARD TOWARD
LYH/DAN/EVEN ROA BY LATE AFTERNOON. HAVE PLAYED SOME POTENTIAL FOR
THIS INTO THE TAFS. OTHERWISE...MOSTLY MVFR CIGS AND MVFR VSBYS IN
VCTS AND/OR TSRA MOSTLY AFT 00Z...AGAIN LITTLE OF WHICH SHOULD
REACH THE PIEDMONT. S-SW WINDS 5-10KTS THROUGH TAF VALID
PERIOD...WITH LOW END GUSTS ACROSS THE PIEDMONT.
MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
AS OF 202 AM EDT WEDNESDAY...
THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT
HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH
SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE.
THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN
SHOWERS ARE EXPECTED THIS MORNING.
A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET
OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES
WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON
CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH
POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN
SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB
WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER
SCTD/BKN 5-6K FT CU FIELDS.
THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD
OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY.
THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG.
HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY
AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/RAB
NEAR TERM...AMS/JH/KK
SHORT TERM...WP
LONG TERM...WP
AVIATION...RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
750 AM EDT WED MAY 22 2013
.SYNOPSIS...
A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO
THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT
THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 AM EDT WEDNESDAY...
A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL
FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST
FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE
RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING
WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA.
HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION
THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE
ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE
CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE
AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS
AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING
NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL
CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON.
EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT
THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE
PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS
INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE
INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN
00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS
CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY
IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH
FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY
THIS EVENING TO COVER THIS POTENTIAL.
THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF
OUR REGION TODAY INTO TONIGHT.
CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT
AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS
TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID
80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID
60S SE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 AM EDT WEDNESDAY...
A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION
BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE
CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY.
OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT
THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE.
LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY
ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION
COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM
PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE
PIEDMONT AND TIDEWATER AREAS OF VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
FRIDAY NIGHT AND SATURDAY:
QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM
FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST
OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE
BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD
GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 AM EDT WEDNESDAY...
PATCHY FOG WILL DISSIPATE QUICKLY...ALTHOUGH IFR CIGS MAY LINGER
ACROSS THE PIEDMONT FROM DAN-LYH FOR A WHILE THIS MORNING.
OTHERWISE...MOSTLY VFR AFT 14Z WITH SC/CU DEVELOPING FROM EARLY
MORNING MOISTURE. MAIN CONCERN WILL COME LATE TODAY AS THE STRONG
COLD FRONT RESPONSIBLE FOR ALL OF THE SEVERE WEATHER IN THE
MIDWEST RECENTLY APPROACHES THE AREA FROM THE WEST. ECMWF/GFS
GENERALLY CONSISTENT ON A LINE OF STRONG THUNDERSTORMS MOVING
INTO FAR SW VA FROM KY/TN IN THE 00Z-04Z TIME FRAME...THEN
GENERALLY DISSIPATING AS IT MOVES TOWARD THE NEW RIVER VALLEY
REGION...SIMILAR TIMING TO WHAT WE SAW YESTERDAY...BUT EXPECT
ACTIVITY TO BE A LITTLE MORE POTENT THIS EVENING. DO NOT EXPECT
THIS ACTIVITY TO SURVIVE AS IT REACHES THE PIEDMONT.
HOWEVER...MODELS SHOW...ESPECIALLY THE GFS...POTENTIAL TSRA
DEVELOPMENT ACROSS THE NC PIEDMONT...LIFTING NORTHWARD TOWARD
LYH/DAN/EVEN ROA BY LATE AFTERNOON. HAVE PLAYED SOME POTENTIAL FOR
THIS INTO THE TAFS. OTHERWISE...MOSTLY MVFR CIGS AND MVFR VSBYS IN
VCTS AND/OR TSRA MOSTLY AFT 00Z...AGAIN LITTLE OF WHICH SHOULD
REACH THE PIEDMONT. S-SW WINDS 5-10KTS THROUGH TAF VALID
PERIOD...WITH LOW END GUSTS ACROSS THE PIEDMONT.
MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
AS OF 202 AM EDT WEDNESDAY...
THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT
HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH
SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE.
THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN
SHOWERS ARE EXPECTED THIS MORNING.
A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET
OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES
WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON
CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH
POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN
SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB
WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER
SCTD/BKN 5-6K FT CU FIELDS.
THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD
OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY.
THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG.
HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY
AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/JH/KK
SHORT TERM...WP
LONG TERM...WP
AVIATION...RAB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
645 AM CDT WED MAY 22 2013
.SHORT TERM...(TODAY AND FRIDAY)
ISSUED AT 309 AM CDT WED MAY 22 2013
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH TONIGHT...
THEN POSSIBLE PATCHY FROST OVER CENTRAL WISCONSIN THURSDAY NIGHT.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL LOW OVER
THE NORTHERN PLAINS AND SHORTWAVE TROUGHS ROTATING AROUND THE UPPER
LEVEL LOW. LATEST MOSAIC RADAR INDICATING SCATTERED SHOWERS
EXTENDING FROM LAKE SUPERIOR INTO SOUTHWEST MINNESOTA AND ANOTHER
AREA OF SHOWERS AND THUNDERSTORMS FROM WESTERN ILLINOIS INTO
SOUTHERN LAKE MICHIGAN.
THE 22.00Z GFS/NAM ARE IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL
FLOW THROUGH FORECAST PERIOD. BOTH MODELS ARE IN DECENT AGREEMENT
LIFTING SHORTWAVE TROUGH OVER MISSOURI AND EASTERN KANSAS
INTO SOUTHERN WISCONSIN TODAY. THE 22.00Z GFS/NAM AND 22.03Z RAP ARE
IN AGREEMENT IN INCREASING PV ADVECTION...QG FORCING AND VERTICAL
MOTION OVER THE FORECAST AREA 12-18Z TODAY AND DEVELOP
PRECIPITATION OVER MUCH OF THE FORECAST AREA BY 18Z TODAY.
CONFIDENCE IS INCREASING THE FORECAST AREA WILL SEE PRECIPITATION
DEVELOP OVER FORECAST AREA BY 18Z. THE DETERMINISTIC MODELS INDICATE
0-6KM MOST UNSTABLE CAPE 300-500 J/KG OVER SOUTHEASTERN HALF OF THE
FORECAST AREA AFTER 15Z TODAY. WILL CONTINUE TO MENTION ISOLATED
THUNDERSTORMS.
THE 22.00Z GFS/NAM SUGGEST UPPER LEVEL LOW WEAKENS AND DRIFTS SLOWLY
EAST INTO THE GREAT LAKES REGION...AS AN UPPER LEVEL TROUGH
DIGS OVER EASTERN GREAT LAKES REGION TONIGHT. WITH SURFACE RIDGE
BUILDING INTO SOUTHERN ONTARIO AND THE WESTERN GREAT LAKES REGION...
CLOUDS AND PRECIPITATION WILL DIMINISH FROM NORTH TO SOUTH ACROSS
FORECAST AREA AFTER 06Z THURSDAY.
DRY NORTHEASTERLY FLOW ALOFT DEVELOPS OVER FORECAST AREA THURSDAY.
THE 22.00Z GFS/NAM BUFKIT SOUNDINGS ARE INDICATING FORECAST AREA
MIXING UP TO 825MB BY 21Z. THIS SHOULD ALLOW FOR DEWPOINTS TO FALL
INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS MUCH OF THE FORECAST AREA
THURSDAY AFTERNOON.
NEXT CONCERN IS LOW TEMPERATURES AND PATCHY FROST FRIDAY MORNING...
WITH THE COMBINATION OF SURFACE RIDGE CENTERED AND DRY AIRMASS OVER
FORECAST AREA...TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE
30S ACROSS PORTIONS OF CENTRAL WISCONSIN. PATCHY FROST WILL BE
POSSIBLE ACROSS THIS PART OF THE FORECAST AREA.
.LONG TERM...(FRIDAY NIGHT INTO TUESDAY)
ISSUED AT 309 AM CDT WED MAY 22 2013
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH FORECAST
PERIOD. THE 22.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON TIMING OF
SHORTWAVE TROUGHS OVER-TOPPING UPPER LEVEL RIDGE OVER THE CENTRAL
UNITED STATES AND PLACEMENT OF THE SURFACE RIDGE OVER THE
GREAT LAKES REGION. WITH THIS...CONFIDENCE IN FORECAST IS LOW AND
WILL CONTINUE WITH CONSISTENCY OF PRECIPITATION CHANCES THROUGH
FORECAST PERIOD. TEMPERATURES WILL CLIMB INTO THE 60S FOR THE
MEMORIAL DAY WEEKEND AND BE IN THE 70S TUESDAY...AS THE
DETERMINISTIC MODELS INDICATE WARMER AIR ALOFT TO FILTER INTO THE
REGION BY 00Z TUESDAY.
&&
.AVIATION...TODAY AND TONIGHT
644 AM CDT WED MAY 22 2013
CLOSED CIRCULATION TO PASS JUST SOUTH OF THE TAF LOCATIONS OVER
THE NEXT 24 HOURS. BROAD AREA OF LIGHT SHOWERS IN THE DEFORMATION
AREA ON THE NORTHERN/WESTERN PERIPHERY. BROAD WEAK LIFT AND
AVAILABLE MOISTURE WILL KEEP SHOWERS GOING...IN AT LEAST HIT-AND-
MISS FASHION...FOR THE BULK OF THE PERIOD. ALSO OF CONCERN ARE LOW
CLOUDS. IFR IS NOT FAR AWAY AND EXPECT IT TO EXPAND BACK INTO OUR
REGION...FIRST AT KRST...AND FINALLY AT KLSE. THE PERSISTANT LOW
SYSTEM WILL FINALLY DEPART ON THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....DTJ
LONG TERM......DTJ
AVIATION...MW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
435 PM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN MOVE
INTO WESTERN PORTIONS OF THE TRI-STATE THURSDAY NIGHT. A WAVE OF
LOW PRESSURE DEVELOPS ALONG THIS SLOW MOVING COLD FRONT
FRIDAY...REMAINS JUST EAST OF THE REGION SATURDAY...AND THEN
TRACKS NORTH ALONG THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE
OVER THE GREAT LAKES BUILDS SOUTHEAST ACROSS THE AREA MONDAY INTO
TUESDAY. A WARM FRONT WILL THEN APPROACH FROM THE SOUTHWEST BY MID
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WEAK FRONTAL BOUNDARY REMAINS STALLED JUST TO THE W AND S OF THE
AREA...WITH A MARINE AIRMASS REMAINING IN PLACE. THIS FRONT SHOULD
NOT MOVE MUCH...IF AT ALL TONIGHT...SO WOULD EXPECT MOST IF NOT
ALL PRECIPITATION TO GO N OF THE AREA. THIS IS CONSISTENT WITH THE
HRRR AND RAP...WHICH HAVE HAD THE BEST HANDLE ON THIS FRONT AND
THE WEATHER TODAY BY FAR...ALONG WITH THE NAM AND SREF.
BASED ON THIS HAVE GONE BASICALLY DRY ACROSS THE S 2/3 OF THE CWA
THIS EVENING...WITH SLIGHT CHANCE POPS FAR N TIER...THEN SLIGHT
CHANCE POPS THROUGHOUT OVERNIGHT IN RESPONSE TO AN APPROACHING
700-500 HPA SHORTWAVE.
WITH MARINE LAYER INTACT - WOULD EXPECT LOW CLOUD DECK TO RE-
ESTABLISH ITSELF ACROSS THE AREA OVERNIGHT. COULD SEE PATCHY FOG
AS WELL - POSSIBLY LOCALLY DENSE NEAR THE ATLANTIC COAST.
FOR LOWS USED A BLEND OF 50 PERCENT MAV GUIDANCE WITH 25 PERCENT
MET GUIDANCE AND 25 PERCENT NAM 2-METER TEMPERATURES. FORECASTING
LOWS 10-15 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MIXING ASSOCIATED WITH PASSING 700-500 HPA SHORTWAVE THURSDAY
MORNING SHOULD ERODE THE MARINE INVERSION - BUT STILL WILL BE
LEFT WITH QUITE A BIT OF MID TO HIGH CLOUDS WITH MOIST SW FLOW
ALOFT.
PRE-FRONTAL TROUGH MOVING INTO THE LOWER HUDSON VALLEY/NE NJ
THURSDAY AFTERNOON SHOULD SERVE AS TRIGGER FOR SCT-NUMEROUS SHRA
WITH EMBEDDED TSRA. LIKELY POPS MAINLY FROM NYC-INTERIOR SW CT
ZONES ON W AND CHANCE POPS EAST OF THAT LINE. SOME SUGGESTION FROM
NAM/GFS THAT EASTERN AREAS WILL REMAIN DRY THURSDAY...BUT FOR NOW
TOO MUCH LOW-MID LEVEL MOISTURE AND INCREASING LOW LEVEL JET TO
FORECAST THAT AT THIS TIME.
WITH 30-35 KT BULK SHEAR...1000-1500 J/KG OF CAPE AND BULK
RICHARDSON NUMBERS 15-30 HAVE THE POTENTIAL FOR ISOLATED SEVERE
STORMS THURSDAY AFTERNOON ACROSS NE NJ/LOWER HUDSON VALLEY AND
MAYBE NYC AND SW CT ZONES. MAIN THREAT IS GUSTY WINDS AND LARGE
HAIL. ALSO NEED TO WATCH FOR LOW LEVEL HELICITY WITH S SFC FLOW
AND SW FLOW AT 850 HPA.
FOR HIGHS THURSDAY USED A BLEND OF MIXING DOWN FROM 975 HPA NEAR
THE COAST AND 950 HPA INLAND...WITH NAM 2-METER TEMPERATURES AND A
BLEND OF MAV AND MET GUIDANCE. FORECASTING VALUES AROUND NORMAL
EAST TO A FEW DEGREES ABOVE NORMAL WEST.
DEEP SW FLOW ALOFT...BECOMES DIFFLUENT AT 500 HPA AFTER MIDNIGHT.
HAVE THE POTENTIAL FOR HEAVY RAINFALL AS A RESULT. REFER TO THE
HYDROLOGY SECTION FOR DETAILS. SEVERE THREAT COULD LINGER INTO THE
EVENING ACROSS WESTERN ZONES AS WELL.
FOR LOWS THURSDAY NIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST AROUND 10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MODELS HAVE TRENDED CONSIDERABLY SLOWER AND DEEPER WITH THE
APPROACHING UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY. THERE
IS VERY GOOD AGREEMENT WITH THE 12Z GFS AND ECMWF ON TAKING A CLOSED
UPPER LOW FROM THE MID ATLANTIC STATES ON FRI NE TO OVER NEW ENGLAND
ON SUN. THE NAM AND GGEM ARE TRENDING IN THAT DIRECTION...BUT ARE
MORE PROGRESSIVE BEYOND 00Z SAT. PREFERENCE AT THIS TIME IS TO GO
WITH THE SLOWER GFS/ECMWF SOLUTION BASED ON MODEL TRENDS AND THE RUN
TO RUN CONTINUITY BEING EXHIBITED OVER THE LAST SEVERAL MODEL CYCLES.
AS FOR SENSIBLE WEATHER...THIS RESULTS IN A WET...COOL WEEKEND WITH
THE POTENTIAL FOR ANOTHER 1 TO 2 INCHES OF RAINFALL IN THE FRI-SAT
TIME FRAME. SINCE THIS IS A BIG ADJUSTMENT FROM THE PREVIOUS
FORECAST...HAVE RAMPED UP RAIN CHANCES FRI INTO SAT...BUT THESE MAY
BE UNDERDONE...ESPECIALLY FOR SAT WHERE THERE IS A TREND IN THE
FORECAST TO DRY THINGS OUT SAT INTO SUN. LATEST ECMWF KEEPS
CONDITIONS WET INTO SUN WITH A GUSTY NW FLOW ON THE BACKSIDE. SO
THIS IS THE POINT IN THE FORECAST WHERE CONDITIONS MAY CONTINUE TO
DETERIORATE WITH SUBSEQUENT MODEL RUNS.
ONCE AGAIN...WHILE THE FORECAST HAS AGGRESSIVELY TAKEN A DOWNWARD
NOTE FOR THE HOLIDAY WEEKEND...RAIN CHANCES MAY BE ON THE INCREASE
SAT INTO SUN BASED ON LATEST TRENDS IN THE MODEL GUIDANCE.
IN ADDITION...SOME OF THE RAINFALL ON FRI...OR AT LEAST THE FIRST
HALF OF THE DAY MAY BE CONVECTIVE WITH LOCALIZED HEAVY RAINFALL WITH
ANY EMBEDDED THUNDERSTORMS. THEREAFTER...THE AIRMASS STABILIZES IN
THE LOW-LEVELS WITH POST-FRONTAL RAIN/SHOWERS...PRIMARILY DRIVEN BY
FRONTOGENETIC FORCING ON THE BACKSIDE OF THE LOW. WIND GUSTS SAT
INTO SUN MAY BE UP TO 35 MPH...BUT THIS IS THE POTENTIAL...WITH THE
FORECASTS SIGNIFICANTLY LOWER AT THIS TIME.
AS FOR TEMPS...DAYTIME HIGHS WITH THE CLOUD COVER AND RAIN WILL BE 5
TO 10 DEGREES BELOW NORMAL. STAYED BELOW GUIDANCE. OVERNIGHT LOWS
WILL BE CLOSE TO SEASONABLE. A GRADUAL WARM-UP TO NEAR SEASONABLE
LEVELS IS THEN FORECAST MON-WED.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON.
AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND
VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE
IMPROVEMENT PRIMARILY AT NW TERMINALS.
IFR CONDITIONS MAY BE A LITTLE SLOWER TO RETURN AT KEWR...KTEB...AND
KSWF OVERNIGHT. HOWEVER...STILL HIGH ENOUGH POTENTIAL THAT IFR
CONDITIONS WERE INCLUDED IN THESE TAFS IN ADDITION TO ALL OTHER
SITES OVERNIGHT. POTENTIAL EXISTS FOR COASTAL TERMINALS TO DROP TO
LIFR AS WELL.
LOW-END CHANCES FOR TS TO AFFECT ANY ONE TERMINAL SITE AFTER 18Z
THURSDAY. HOWEVER...DID INCLUDE PROB30 GROUPS AT 30-HOUR SITES TO
INDICATE THE GROWING POTENTIAL LATE IN THE DAY.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.
KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY EARLY
THIS EVENING.
KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS.
KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS.
KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.
.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY
THUR NIGHT AND FRIDAY. IFR POSSIBLE IN FOG AND STRATUS.
.SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT.
.SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR G
UP TO 40KT.
.MONDAY...VFR. NW WINDS 15-20G25KT.
&&
.MARINE...
LATEST SATELLITE IMAGERY...WEB-CAMS...AND RAP SOUNDINGS WARRANT
EXTENDING DENSE FOG ADVISORY FOR THE WATERS S/W OF LONG ISLAND
THROUGH TONIGHT. MIGHT ULTIMATELY END UP NEED TO EXTEND INTO
THURSDAY MORNING - BUT TO MUCH UNCERTAINTY WITH TIMING OF MIXING
AHEAD OF APPROACHING SHORTWAVE LATE TONIGHT TO DO SO AT THIS TIME.
SEAS ARE RUNNING 1-2 FT BELOW WAVEWATCH FORECAST - SO FOR NOW HAVE
TAKEN 1 FT OFF OF WAVEWATCH THROUGH THURSDAY NIGHT. STILL EXPECT
SEAS TO COME UP TO SCA LEVELS TONIGHT AND CONTINUE THROUGH
THURSDAY NIGHT. WINDS ALSO INCREASE LATE TONIGHT AND REMAIN UP
INTO THURSDAY NIGHT. INCREASING LOW LEVEL JET THROUGH THURSDAY
NIGHT INCREASES POTENTIAL FOR SCA LEVEL GUSTS OVER THE COASTAL
OCEAN WATERS - SO HAVE KEPT HEADLINE AS SCA VICE CONVERTING TO AN
SCA FOR HAZARDOUS SEAS.
MARINE INVERSION APPEARS WILL LIMIT MIXING - SO WHILE COULD SEE
OCCASIONAL GUSTS TO 25 KT OVER THE REMAINDER OF THE WATERS FROM
LATE TONIGHT INTO THURSDAY NIGHT - DO NOT HAVE CONFIDENCE TO ISSUE
SCA AT THIS TIME FOR THE NON-OCEAN ZONES.
THERE IS A GOOD POTENTIAL FOR SCA CONDITIONS TO CONTINUE THROUGH THE
UPCOMING WEEKEND AS LOW PRESSURE FORMS OVER THE WATERS ON FRI AND
LIFTS SLOWLY TO THE NORTH AND EAST. SCA CONDITIONS ARE BECOMING
INCREASINGLY LIKELY...WITH THE POTENTIAL FOR GALE CONDITIONS SAT
INTO SUN. WINDS AND SEAS BEGIN TO SUBSIDE LATE SUN INTO MON WITH
HIGH PRESSURE BUILDING IN FROM THE GREAT LAKES REGION.
&&
.HYDROLOGY...
THERE IS THE POTENTIAL FOR AROUND 3/4 TO 1 INCH BASIN AVERAGE QPF
THURSDAY AND THURSDAY NIGHT WITH LOCALLY HIGHER AMOUNTS.
DO NOT EXPECT ANY WIDESPREAD FLOOD THREAT THURSDAY FROM ANY
SHRA/TSRA BUT COULD SEE SOME MINOR FLOODING UNDER ANY STRONGER
CONVECTION - ESPECIALLY IF THERE IS ANY TRAINING.
THE HEAVIEST RAINFALL IN THIS TIME FRAME WILL BE LATE THURSDAY
NIGHT - WITH LOCALIZED RAINFALL RATES OF 1-1.5 INCHES/HR POSSIBLE
NOTING PRECIPITABLE WATERS OF 1.5-1/75 INCHES IN THIS TIME
FRAME. IF THESE RATES ARE REALIZED...ESPECIALLY IF THE STORMS
PRODUCING THEM PASS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL
THURSDAY...THERE IS THE POTENTIAL FOR LOCALIZED FLASH FLOODING.
THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL CONTINUE INTO THE FIRST
HALF OF FRI WITH EMBEDDED CONVECTION. THEREAFTER...A STRATIFORM RAIN
AND/OR SHOWERS DEVELOPS ON THE BACKSIDE OF DEVELOPING LOW PRESSURE.
AN ADDITIONAL 1 TO 2 INCHES OF RAINFALL IS POSSIBLE FRI INTO SAT.
THIS MAY EXACERBATE ANY ONGOING FLOODING. RAIN MAY LINGER EVEN INTO
SUN BASED ON LATEST MODEL TRENDS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ338-345-350-
353-355.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...MALOIT/DW
NEAR TERM...MALOIT
SHORT TERM...MALOIT
LONG TERM...DW
AVIATION...PICCA/MET
MARINE...MALOIT/DW
HYDROLOGY...MALOIT/DW
AREA FORECAST DISCUSSION
NWS ALBANY NY
433 PM EDT WED MAY 22 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH THE REGION INTO FRIDAY. PERIODS
OF SHOWERS AND THUNDERSTORMS WILL PRECEDE THE FRONT. THE RAIN WILL
BE HEAVY AT TIMES. COOLER AND SHOWERY CONDITIONS WILL PERSIST
INTO THE FIRST HALF OF THE MEMORIAL DAY WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
...SEVERE THUNDERSTORM WATCH 210 IN EFFECT UNTIL 10 PM...
MAIN BAND OF CONVECTION AND ASSOCIATED SEVERE WEATHER AND FLOODING
RAINFALL CONTINUES TO PROGRESS EAST. SOME REPORTS OF WIND DAMAGE
IN SCHENECTADY AND SCHOHARIE COUNTIES. MEANWHILE...HEAVY
RAINFALL...RADAR ESTIMATE SHOWS 2-3 INCHES HAS LED TO URBAN
FLOODING IN SCHENECTADY COUNTY.
WITH MCS-LIKE SYSTEM CONTINUING TO TRACK NORTHEAST THROUGH THE
LATE AFTERNOON SEVERE THREAT/FLASH FLOOD THREAT WILL CONTINUE EAST.
ATTENTION WILL TURN TO ACTIVITY FOR LATER THIS AFTERNOON AND
TONIGHT. CURRENTLY TO OUR WEST LAKE BREEZES ARE FORCING ISOLD
TSRA. HRRR SHOWS LAKE BREEZE TO BLOSSOM WITH CONVECTION INTO LATER
THIS AFTERNOON AND EVENING AS LARGER SCALE ASCENT TRANSLATES
EASTWARD FROM LOWER LAKES. INSTABILITY HAS RECOVERED ACROSS
WESTERN CWA WITH MESOANALYSIS SHOWS CAPES IN 1500-2000 J/KG RANGE.
BULK SHEAR WILL REMAIN FAVORABLE FOR SEVERE STORMS WITH VALUES
INTO THE 30-40 KNOT RANGE. WILL CARRY ENHANCED WORDING TO COINCIDE
WITH WATCH...THEN SCT SHRA/TSRA THROUGH REMAINDER OF OVERNIGHT AS
WAIT TO SEE HOW CONVECTION EVOLVES.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
COLD FRONT SLOWLY APPROACHES THE REGION ON THURSDAY...NOT CLEARING
CWA UNTIL FRIDAY MORNING.
SLOWLY MOVING FRONT WILL PROVIDE ENVIRONMENT FOR BOUTS OF HEAVY
RAIN THROUGH THE PERIOD. PWATS REMAIN IN THE 1.5 INCH RANGE
THROUGH THURSDAY...ONLY SLOWLY DROPPING OFF INTO FRIDAY.
APPROACHING UPPER LEVEL JET TOMORROW BRINGS RIGHT REAR QUAD INTO
FORECAST AREA FOR THE AFTERNOON. SEE HYDRO SECTION FOR DISCUSSION
ON FLOOD RISK.
SEVERE POTENTIAL TOMORROW IS NOT CLEAR CUT NOW. MODEL CAPE LOOKS
TO BE IN THE 1000 J/KG RANGE WITH BULK SHEAR RESPECTABLE IN THE
30-40 KNOT RANGE. MID LEVEL LAPSE RATES ARE RELATIVELY WEAK AT
5.5C/KM. SPC HAS REGION IN SEE TEXT. FROM TODAY/S VANTAGE POINT
THAT LOOKS APPROPRIATE.
WITH COLD FRONT MOVING THROUGH ON FRIDAY...SOME DIMINISHING IN
PRECIP EXPECTED FOR PART OF FRIDAY. HOWEVER GFS AND ECMWF COMING
INTO AGREEMENT ON CUT OFF MIGRATING SLOWLY FROM DELMARVA INTO NEW
ENGLAND INTO THE HOLIDAY WEEKEND. THIS WILL KEEP THE THREAT OF
RAIN/SHOWERS IN THE FORECAST FOR FRIDAY. WITH CWA ON COOL SIDE OF
SURFACE LOW TRACK...INSTABILITY LOOKS NEAR NIL. SO NO MENTION OF
TSRA FOR FRIDAY.
MINS ON SATURDAY MORNING IN ADIRONDACKS ARE FORECAST IN MID 30S.
THIS WOULD MEAN THREAT OF FROST GIVEN BEGINNING OF THE GROWING
SEASON THERE. WILL DEPEND ON CLOUDS AND PRECIP.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODEL GUIDANCE HAS TRENDED TO A WET START TO THE HOLIDAY WEEKEND
ALONG WITH CHILLY TEMPERATURES DUE TO MORE CLOUD COVER.
THE MODEL GUIDANCE HAS COME INTO FAIRLY GOOD AGREEMENT THAT AN AREA
OF LOW PRESSURE WILL FORM ON THE COLD FRONT JUST OFF COAST NEAR CAPE
COD AS SHORT WAVES MOVE THROUGH THE LONGWAVE. AN UPPER LEVEL LOW IS
EXPECTED TO DEVELOP OVER THE MID ATLANTIC REGION FRIDAY NIGHT WITH
ADDITIONAL SHORT WAVES MAINTAINING THIS UPPER LOW WITH IT MOVING
GRADUALLY NORTHWARD UP THE COAST. THE LOW ALONG THE BOUNDARY WILL
SLOW THE FRONT`S EASTWARD PROGRESS AND THROW RAIN SHOWERS AND CLOUDS
BACK ACROSS NEW ENGLAND AND EASTERN NEW YORK STATE SATURDAY. THE
REGION WILL REMAIN UNDER CYCLONIC FLOW THROUGH THE WEEKEND WITH
UPPER RIDGING NOT EXPECTED TO BEGIN TO BUILD IN UNTIL TUESDAY. AT
THE SURFACE...HIGH PRESSURE SHOULD BEGIN TO BUILD IN MONDAY AND
ESPECIALLY TUESDAY. IT APPEARS THE HIGH SHOULD HOLD ON FOR WEDNESDAY.
AS FOR TEMPERATURES...CHILLY. TEMPERATURES ARE EXPECTED TO RUN 10 TO
15 DEGREES BELOW NORMAL SATURDAY AND AGAIN SUNDAY. BRISK AND GUSTY
NORTHWESTERLY WINDS WILL ONLY ADD TO THE CHILL. TEMPERATURES ARE
EXPECTED TO MODERATE TOWARD SEASONABLE LEVELS MONDAY WITH THE HELP
OF SUNSHINE BUT STILL BE BELOW NORMAL BY AROUND 5 DEGREES.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK
VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND
EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON
MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY.
NIGHTTIME LOWS OVER THE WEEKEND ARE EXPECTED TO BE IN THE 40S WITH
30S ACROSS THE HIGHER TERRAIN. WITH THE EXPANSION OF THE GROWING
SEASON BY THIS TIME FROST ADVISORIES MIGHT BE NEEDED. CONDITIONS
WILL BE MORE FAVORABLE FOR FROST SUNDAY NIGHT/MONDAY MORNING AND
MONDAY NIGHT/TUESDAY MORNING.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR PREVAILING WITH PERIODS OF MVFR FOR THE BALANCE OF THE
AFTERNOON. SCATTERED -SHRA AND TSRA WILL DIRECTLY AFFECT OR BE IN
THE VICINITY OF THE AIRPORTS FROM THE START OF THE TAF PERIOD
THROUGH AT LEAST 22Z. CLOUDS WILL BE HARD TO CLEAR
OUT...PARTICULARLY THE HIGH-LEVEL CI/CS...WHICH SHOULD LIMIT
INSTABILITY AND THE PROLIFERATION OF TS. HIGH DEWPOINTS OVERNIGHT
WILL RESULT IN SOME HAZY FOG...MAINLY MVFR...WITH A PERIOD OF IFR
FOG POSS AT KPSF WHERE WINDS THRU THE COLUMN WILL BE LIGHTER.
WITH LITTLE CHANGE IN THE ENVIRONMENT EXPECTED INTO EARLY
THURSDAY...MVFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE AIRPORTS
INTO THE EARLY AFTERNOON HOURS...WITH MORE TS ACTIVITY IS
LIKELY...THOUGH PERHAPS NOT UNTIL AFTER THE END OF THE TAF PERIOD.
EXPECTING A PERIOD OF MARGINAL SHEAR DURING THE EARLY NIGHT EXCEPT
AT KPSF...35 KNOTS SHOULD BE ABOUT IT. SURFACE WINDS WILL HOLD UP
OVERNIGHT AT LESS THAN 10 KNOTS...PICKING UP TO SPEEDS ON THURSDAY
AVERAGING SLIGHTLY HIGHER THAN TODAY.
OUTLOOK...
THU PM AND NGT...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
FRI-FRI NGT...MAINLY VFR. CHC -SHRA/-TSRA...MAINLY IN THE AM.
SAT-SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS INTO SATURDAY. PERIODS OF RAIN...MODERATE
TO HEAVY AT TIMES WILL CONTINUE INTO THE HOLIDAY WEEKEND.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THURSDAY AFTERNOON.
WINDS WILL GENERALLY BE SOUTH AT 5 TO 10 MPH.
&&
.HYDROLOGY...
ECMWF AND GFS VERY AGGRESSIVE IN BRINGING HEAVY RAINFALL INTO CWA
INTO THE MEMORIAL DAY WEEKEND. OPERATIONAL ECMWF AND GFS PRODUCE
5-7.5 INCHES OF RAIN IN CWA INTO SUNDAY. GEFS SHOW AVERAGE OF 2.25
INCHES THROUGH WEEKEND WITH 4 MEMBERS PUSHING IN EXCESS OF 3
INCHES. WHILE NOT QUITE READY TO ACCEPT TOTALS OF EURO AND
GFS...ENOUGH GUIDANCE AVAILABLE TO AT LEAST WARRANT POTENTIAL OF
HEAVY RAIN THREAT IN HWO. FIRST CHALLENGE FOR HEAVY RAIN WILL COME
TOMORROW WITH SLOWLY MOVING FRONT. EASTERN CWA AND CENTRAL CWA
HAVE SEEN HEAVIEST RAIN OVER THE LAST TWO DAYS AND WOULD APPEAR TO
BE THE REGION WHERE FLASH FLOOD THREAT IS AT HIGHEST.
WILL MONITOR CLOSELY FOR AT LEAST POTENTIAL OF FLASH FLOOD OR
FLOOD WATCH THURSDAY INTO WEEKEND.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...OKEEFE
NEAR TERM...OKEEFE
SHORT TERM...OKEEFE
LONG TERM...IAA
AVIATION...ELH/WASULA
FIRE WEATHER...OKEEFE
HYDROLOGY...OKEEFE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
407 PM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN MOVE
INTO WESTERN PORTIONS OF THE TRI-STATE THURSDAY NIGHT. A WAVE OF
LOW PRESSURE DEVELOPS ALONG THIS SLOW MOVING COLD FRONT
FRIDAY...REMAINS JUST EAST OF THE REGION SATURDAY...AND THEN
TRACKS NORTH ALONG THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE
OVER THE GREAT LAKES BUILDS SOUTHEAST ACROSS THE AREA MONDAY INTO
TUESDAY. A WARM FRONT WILL THEN APPROACH FROM THE SOUTHWEST BY MID
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WEAK FRONTAL BOUNDARY REMAINS STALLED JUST TO THE W AND S OF THE
AREA...WITH A MARINE AIRMASS REMAINING IN PLACE. THIS FRONT SHOULD
NOT MOVE MUCH...IF AT ALL TONIGHT...SO WOULD EXPECT MOST IF NOT
ALL PRECIPITATION TO GO N OF THE AREA. THIS IS CONSISTENT WITH THE
HRRR AND RAP...WHICH HAVE HAD THE BEST HANDLE ON THIS FRONT AND
THE WEATHER TODAY BY FAR...ALONG WITH THE NAM AND SREF.
BASED ON THIS HAVE GONE BASICALLY DRY ACROSS THE S 2/3 OF THE CWA
THIS EVENING...WITH SLIGHT CHANCE POPS FAR N TIER...THEN SLIGHT
CHANCE POPS THROUGHOUT OVERNIGHT IN RESPONSE TO AN APPROACHING
700-500 HPA SHORTWAVE.
WITH MARINE LAYER INTACT - WOULD EXPECT LOW CLOUD DECK TO RE-
ESTABLISH ITSELF ACROSS THE AREA OVERNIGHT. COULD SEE PATCHY FOG
AS WELL - POSSIBLY LOCALLY DENSE NEAR THE ATLANTIC COAST.
FOR LOWS USED A BLEND OF 50 PERCENT MAV GUIDANCE WITH 25 PERCENT
MET GUIDANCE AND 25 PERCENT NAM 2-METER TEMPERATURES. FORECASTING
LOWS 10-15 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MIXING ASSOCIATED WITH PASSING 700-500 HPA SHORTWAVE THURSDAY
MORNING SHOULD ERODE THE MARINE INVERSION - BUT STILL WILL BE
LEFT WITH QUITE A BIT OF MID TO HIGH CLOUDS WITH MOIST SW FLOW
ALOFT.
PRE-FRONTAL TROUGH MOVING INTO THE LOWER HUDSON VALLEY/NE NJ
THURSDAY AFTERNOON SHOULD SERVE AS TRIGGER FOR SCT-NUMEROUS SHRA
WITH EMBEDDED TSRA. LIKELY POPS MAINLY FROM NYC-INTERIOR SW CT
ZONES ON W AND CHANCE POPS EAST OF THAT LINE. SOME SUGGESTION FROM
NAM/GFS THAT EASTERN AREAS WILL REMAIN DRY THURSDAY...BUT FOR NOW
TOO MUCH LOW-MID LEVEL MOISTURE AND INCREASING LOW LEVEL JET TO
FORECAST THAT AT THIS TIME.
WITH 30-35 KT BULK SHEAR...1000-1500 J/KG OF CAPE AND BULK
RICHARDSON NUMBERS 15-30 HAVE THE POTENTIAL FOR ISOLATED SEVERE
STORMS THURSDAY AFTERNOON ACROSS NE NJ/LOWER HUDSON VALLEY AND
MAYBE NYC AND SW CT ZONES. MAIN THREAT IS GUSTY WINDS AND LARGE
HAIL. ALSO NEED TO WATCH FOR LOW LEVEL HELICITY WITH S SFC FLOW
AND SW FLOW AT 850 HPA.
FOR HIGHS THURSDAY USED A BLEND OF MIXING DOWN FROM 975 HPA NEAR
THE COAST AND 950 HPA INLAND...WITH NAM 2-METER TEMPERATURES AND A
BLEND OF MAV AND MET GUIDANCE. FORECASTING VALUES AROUND NORMAL
EAST TO A FEW DEGREES ABOVE NORMAL WEST.
DEEP SW FLOW ALOFT...BECOMES DIFFLUENT AT 500 HPA AFTER MIDNIGHT.
HAVE THE POTENTIAL FOR HEAVY RAINFALL AS A RESULT. REFER TO THE
HYDROLOGY SECTION FOR DETAILS. SEVERE THREAT COULD LINGER INTO THE
EVENING ACROSS WESTERN ZONES AS WELL.
FOR LOWS THURSDAY NIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST AROUND 10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MODELS HAVE TRENDED CONSIDERABLY SLOWER AND DEEPER WITH THE
APPROACHING UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY. THERE
IS VERY GOOD AGREEMENT WITH THE 12Z GFS AND ECMWF ON TAKING A CLOSED
UPPER LOW FROM THE MID ATLANTIC STATES ON FRI NE TO OVER NEW ENGLAND
ON SUN. THE NAM AND GGEM ARE TRENDING IN THAT DIRECTION...BUT ARE
MORE PROGRESSIVE BEYOND 00Z SAT. PREFERENCE AT THIS TIME IS TO GO
WITH THE SLOWER GFS/ECMWF SOLUTION BASED ON MODEL TRENDS AND THE RUN
TO RUN CONTINUITY BEING EXHIBITED OVER THE LAST SEVERAL MODEL CYCLES.
AS FOR SENSIBLE WEATHER...THIS RESULTS IN A WET...COOL WEEKEND WITH
THE POTENTIAL FOR ANOTHER 1 TO 2 INCHES OF RAINFALL IN THE FRI-SAT
TIME FRAME. SINCE THIS IS A BIG ADJUSTMENT FROM THE PREVIOUS
FORECAST...HAVE RAMPED UP RAIN CHANCES FRI INTO SAT...BUT THESE MAY
BE UNDERDONE...ESPECIALLY FOR SAT WHERE THERE IS A TREND IN THE
FORECAST TO DRY THINGS OUT SAT INTO SUN. LATEST ECMWF KEEPS
CONDITIONS WET INTO SUN WITH A GUSTY NW FLOW ON THE BACKSIDE. SO
THIS IS THE POINT IN THE FORECAST WHERE CONDITIONS MAY CONTINUE TO
DETERIORATE WITH SUBSEQUENT MODEL RUNS.
ONCE AGAIN...WHILE THE FORECAST HAS AGGRESSIVELY TAKEN A DOWNWARD
NOTE FOR THE HOLIDAY WEEKEND...RAIN CHANCES MAY BE ON THE INCREASE
SAT INTO SUN BASED ON LATEST TRENDS IN THE MODEL GUIDANCE.
IN ADDITION...SOME OF THE RAINFALL ON FRI...OR AT LEAST THE FIRST
HALF OF THE DAY MAY BE CONVECTIVE WITH LOCALIZED HEAVY RAINFALL WITH
ANY EMBEDDED THUNDERSTORMS. THEREAFTER...THE AIRMASS STABILIZES IN
THE LOW-LEVELS WITH POST-FRONTAL RAIN/SHOWERS...PRIMARILY DRIVEN BY
FRONTOGENETIC FORCING ON THE BACKSIDE OF THE LOW. WIND GUSTS SAT
INTO SUN MAY BE UP TO 35 MPH...BUT THIS IS THE POTENTIAL...WITH THE
FORECASTS SIGNIFICANTLY LOWER AT THIS TIME.
AS FOR TEMPS...DAYTIME HIGHS WITH THE CLOUD COVER AND RAIN WILL BE 5
TO 10 DEGREES BELOW NORMAL. STAYED BELOW GUIDANCE. OVERNIGHT LOWS
WILL BE CLOSE TO SEASONABLE. A GRADUAL WARM-UP TO NEAR SEASONABLE
LEVELS IS THEN FORECAST MON-WED.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON.
AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND
VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE
IMPROVEMENT PRIMARILY AT NW TERMINALS.
RECENT OBS SHOW WINDS FINALLY TURNING S AT KJFK/KEWR...WHICH MAY
BE A SIGN OF BRIEFLY INCREASING VSBY/CIGS. HOWEVER...BASED ON
CURRENT OBS AND DEVELOPING S WIND...GROWING POTENTIAL FOR IFR
VSBY TO PUSH BACK INTO COASTAL TERMINALS OVER NEXT FEW HOURS.
POTENTIAL FOR CONDITIONS TO DROP SOLIDLY INTO IFR AGAIN
TONIGHT...HOWEVER MUCH UNCERTAINTY EXISTS OVER TIMING AND EXTENT.
POTENTIAL ALSO EXISTS FOR LIFR/VLIFR ACROSS COASTAL TERMINALS.
DID NOT SHOW TS IN TAFS ON THURSDAY JUST YET...AS UPPER-LEVEL FLOW
INDICATES STORMS MAY BE SLOW TO APPROACH WESTERN TERMINALS AND
COULD HOLD OFF UNTIL LATE IN THE DAY. HOWEVER...LOW END
POTENTIAL EXISTS AT W TERMS GENERALLY 23/18Z THROUGH 24/00Z.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.
KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY THIS
AFTERNOON AND EARLY THIS EVENING. WIND DIRECTION MAY STAY E/NE A
COUPLE HOURS LONGER THAN INDICATED IN TAF.
KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.
.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY
THUR NIGHT AND FRIDAY. IFR POSSIBLE IN FOG AND STRATUS.
.SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT.
.SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR G
UP TO 40KT.
.MONDAY...VFR. NW WINDS 15-20G25KT.
&&
.MARINE...
LATEST SATELLITE IMAGERY...WEB-CAMS...AND RAP SOUNDINGS WARRANT
EXTENDING DENSE FOG ADVISORY FOR THE WATERS S/W OF LONG ISLAND
THROUGH TONIGHT. MIGHT ULTIMATELY END UP NEED TO EXTEND INTO
THURSDAY MORNING - BUT TO MUCH UNCERTAINTY WITH TIMING OF MIXING
AHEAD OF APPROACHING SHORTWAVE LATE TONIGHT TO DO SO AT THIS TIME.
SEAS ARE RUNNING 1-2 FT BELOW WAVEWATCH FORECAST - SO FOR NOW HAVE
TAKEN 1 FT OFF OF WAVEWATCH THROUGH THURSDAY NIGHT. STILL EXPECT
SEAS TO COME UP TO SCA LEVELS TONIGHT AND CONTINUE THROUGH
THURSDAY NIGHT. WINDS ALSO INCREASE LATE TONIGHT AND REMAIN UP
INTO THURSDAY NIGHT. INCREASING LOW LEVEL JET THROUGH THURSDAY
NIGHT INCREASES POTENTIAL FOR SCA LEVEL GUSTS OVER THE COASTAL
OCEAN WATERS - SO HAVE KEPT HEADLINE AS SCA VICE CONVERTING TO AN
SCA FOR HAZARDOUS SEAS.
MARINE INVERSION APPEARS WILL LIMIT MIXING - SO WHILE COULD SEE
OCCASIONAL GUSTS TO 25 KT OVER THE REMAINDER OF THE WATERS FROM
LATE TONIGHT INTO THURSDAY NIGHT - DO NOT HAVE CONFIDENCE TO ISSUE
SCA AT THIS TIME FOR THE NON-OCEAN ZONES.
THERE IS A GOOD POTENTIAL FOR SCA CONDITIONS TO CONTINUE THROUGH THE
UPCOMING WEEKEND AS LOW PRESSURE FORMS OVER THE WATERS ON FRI AND
LIFTS SLOWLY TO THE NORTH AND EAST. SCA CONDITIONS ARE BECOMING
INCREASINGLY LIKELY...WITH THE POTENTIAL FOR GALE CONDITIONS SAT
INTO SUN. WINDS AND SEAS BEGIN TO SUBSIDE LATE SUN INTO MON WITH
HIGH PRESSURE BUILDING IN FROM THE GREAT LAKES REGION.
&&
.HYDROLOGY...
THERE IS THE POTENTIAL FOR AROUND 3/4 TO 1 INCH BASIN AVERAGE QPF
THURSDAY AND THURSDAY NIGHT WITH LOCALLY HIGHER AMOUNTS.
DO NOT EXPECT ANY WIDESPREAD FLOOD THREAT THURSDAY FROM ANY
SHRA/TSRA BUT COULD SEE SOME MINOR FLOODING UNDER ANY STRONGER
CONVECTION - ESPECIALLY IF THERE IS ANY TRAINING.
THE HEAVIEST RAINFALL IN THIS TIME FRAME WILL BE LATE THURSDAY
NIGHT - WITH LOCALIZED RAINFALL RATES OF 1-1.5 INCHES/HR POSSIBLE
NOTING PRECIPITABLE WATERS OF 1.5-1/75 INCHES IN THIS TIME
FRAME. IF THESE RATES ARE REALIZED...ESPECIALLY IF THE STORMS
PRODUCING THEM PASS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL
THURSDAY...THERE IS THE POTENTIAL FOR LOCALIZED FLASH FLOODING.
THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL CONTINUE INTO THE FIRST
HALF OF FRI WITH EMBEDDED CONVECTION. THEREAFTER...A STRATIFORM RAIN
AND/OR SHOWERS DEVELOPS ON THE BACKSIDE OF DEVELOPING LOW PRESSURE.
AN ADDITIONAL 1 TO 2 INCHES OF RAINFALL IS POSSIBLE FRI INTO SAT.
THIS MAY EXACERBATE ANY ONGOING FLOODING. RAIN MAY LINGER EVEN INTO
SUN BASED ON LATEST MODEL TRENDS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ338-345-350-
353-355.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...MALOIT/DW
NEAR TERM...MALOIT
SHORT TERM...MALOIT
LONG TERM...DW
AVIATION...PICCA
MARINE...MALOIT/DW
HYDROLOGY...MALOIT/DW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
215 PM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN PASS
THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE
WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BACK DOOR COLD FRONT THAT WENT THROUGH OVERNIGHT REMAINS STALLED
OUT TO THE W AND S OF THE AREA. HRRR AND RAP ARE THE ONLY MODELS WITH
ANY CLUE TO ITS EXISTENCE. LOOKING AT TRENDS IN VISIBLE SATELLITE
AND RAP SOUNDINGS...HAVE DOUBTS ABOUT HRRR/RAP SHOWING BOUNDARY
PUSH BACK INTO FAR W ZONES AS A WARM FRONT LATE THIS AFTERNOON.
AS A RESULT HAVE KEPT FORECAST CLOUDY-MOSTLY CLOUDY AND LOWERED
TEMPERATURES AGAIN. NOW FORECASTING HIGHS MAINLY IN THE 70S...WITH
UPPER 60S AT THE IMMEDIATE COAST.
STILL APPEARS MOST OF THE AREA WILL BE DRY THIS AFTERNOON PER
HRRR/RAP. HOWEVER WITH CONVECTION FIRING W OF AREA...HAVE KEPT
SLIGHT CHANCE TO CHANCE POPS THIS AFTERNOON OVER THE NW 1/2 OF THE
CWA WITH A SLIGHT CHANCE OF THUNDER. ANY THUNDERSTORMS WILL MOST
LIKELY BE ELEVATED IN NATURE AS THEY MOVE OVER THE AREA DUE TO THE
MARINE INVERSION IN PLACE...SO THE SEVERE THREAT THIS AFTERNOON IS
NIL ACROSS THE SE 1/2 OF THE CWA AND LESS THAN 5 PERCENT ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
INCREASING CONCERN THAT THE MARINE LAYER WILL NOT DISSIPATE/FRONT
LIFT TO THE N BY THIS EVENING - AND THAT THE MARINE LAYER WILL
MAINTAIN ITSELF OVER MOST IF NOT ALL THE AREA TONIGHT. WILL
CONTINUE TO MONITOR TRENDS - BUT COULD END UP MAKING SIGNIFICANT
CHANGES TO TONIGHTS FORECAST IF CURRENT TRENDS HOLD.
SCT-ISOLD SHOWERS AND TSTMS THIS EVENING. CONVECTION SHOULD BE
SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE. SHOWERS
AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS THE
UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACH THE
AREA.
HIGHS ON THURSDAY IN THE MID TO UPPER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE
EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM
SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE
COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES
AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS
AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD
RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH
MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE
ALSO TRENDED A BIT SLOWER WITH PRECIPITATION GRADUALLY TAPERING
OFF FRI AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL
NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS
DOWN EVEN FURTHER.
AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION
THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO
MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM
DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF
APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD
DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT
WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED
WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF
INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE
COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE
THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN
THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD
PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH
FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS.
AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED
HIGHER AMOUNTS.
A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD
ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO
THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES
SEVERAL DEGREES BELOW SEASONABLE LEVELS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON.
AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND
VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE
IMPROVEMENT PRIMARILY AT NW TERMINALS.
RECENT OBS SHOW WINDS FINALLY TURNING S AT KJFK/KEWR...WHICH MAY
BE A SIGN OF BRIEFLY INCREASING VSBY/CIGS. HOWEVER...BASED ON
CURRENT OBS AND DEVELOPING S WIND...GROWING POTENTIAL FOR IFR
VSBY TO PUSH BACK INTO COASTAL TERMINALS OVER NEXT FEW HOURS.
POTENTIAL FOR CONDITIONS TO DROP SOLIDLY INTO IFR AGAIN
TONIGHT...HOWEVER MUCH UNCERTAINTY EXISTS OVER TIMING AND EXTENT.
POTENTIAL ALSO EXISTS FOR LIFR/VLIFR ACROSS COASTAL TERMINALS.
DID NOT SHOW TS IN TAFS ON THURSDAY JUST YET...AS UPPER-LEVEL FLOW
INDICATES STORMS MAY BE SLOW TO APPROACH WESTERN TERMINALS AND
COULD HOLD OFF UNTIL LATE IN THE DAY. HOWEVER...LOW END
POTENTIAL EXISTS AT W TERMS GENERALLY 23/18Z THRU 24/00Z.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.
KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY THIS
AFTERNOON AND EARLY THIS EVENING. WIND DIRECTION MAY STAY E/NE A
COUPLE HOURS LONGER THAN INDICATED IN TAF.
KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF
OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST
TONIGHT.
KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER
THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING.
.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY
THUR NIGHT AND FRIDAY. IFR POSSIBLE IN FOG AND STRATUS.
.SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT.
.SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR G
UP TO 40KT.
.MONDAY...VFR. NW WINDS 15-20G25KT.
&&
.MARINE...
BASED ON HRRR AND LATEST TRENDS IN OBSERVATIONS AND WEB-CAMS HAVE
EXTENDED THE DENSE FOG ADVISORY FOR THE COASTAL OCEAN ZONES...NY
HARBOR AND THE SOUTH SHORE BAYS OF LONG ISLAND THROUGH 22Z. GIVEN
NO RESTRICTIONS OF 1NM OR LESS IN VISIBILITY EVIDENT ON SOUND OR
EASTERN BAYS OF LONG ISLAND...HAVE CANCELLED THE DENSE FOG
ADVISORY THERE.
THERE SEEMS TO BE INCREASING POTENIAL FOR DENSE FOG OVER THE
SOUTHERN WATERS TO CONTINUE TONIGHT. IF TRENDS HOLD...WILL EXTEND
THE DENSE FOG ADVISORY IN TIME THROUGH TONIGHT WITH THE LATE
AFTERNOON FORECAST ISSUANCE.
SEAS ARE NOT INCREASING AS FAST AS FORECAST...SO HAVE ADJUSTED
DOWNWARD A FOOT OR SO ACROSS MOST OCEAN AREAS INTO THIS EVENING.
SEAS SLOWLY BUILD THIS AFTERNOON/EVENING TO SCA LEVELS ON THE
COASTAL OCEAN WATERS AND REMAIN ABOVE SCA LEVELS THROUGH
THURSDAY. SW FLOW INCREASES OVER THE COASTAL OCEAN WATERS TONIGHT
AS WELL WITH SFC BOUNDARY LIFTING TO NEAR THE LONG ISLAND COAST IF
NOT FARTHER N.
A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY
THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE
WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS
THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE
SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY
SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS
SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH
SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST
THE MODELS.
&&
.HYDROLOGY...
SCT SHOWERS/TSTMS THIS EVENING WILL BE CAPABLE OF PRODUCING
LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC.
TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH
LOCALLY HIGHER AMOUNTS IN TSTMS.
SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE
THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN
RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS.
THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD
RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE
LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ338-345-
350-353-355.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT
THURSDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...24/NV
NEAR TERM...MALOIT/NV
SHORT TERM...24
LONG TERM...NV
AVIATION...PICCA
MARINE...24/MALOIT/NV
HYDROLOGY...24/NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1249 PM EDT WED MAY 22 2013
.SYNOPSIS...
A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD
FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN PASS
THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE
WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BACK DOOR COLD FRONT THAT WENT THROUGH OVERNIGHT REMAINS STALLED
OUT TO THE W AND S OF THE AREA. HRRR AND RAP ARE THE ONLY MODELS WITH
ANY CLUE TO ITS EXISTENCE. LOOKING AT TRENDS IN VISIBLE SATELLITE
AND RAP SOUNDINGS...HAVE DOUBTS ABOUT HRRR/RAP SHOWING BOUNDARY
PUSH BACK INTO FAR W ZONES AS A WARM FRONT LATE THIS AFTERNOON.
AS A RESULT HAVE KEPT FORECAST CLOUDY-MOSTLY CLOUDY AND LOWERED
TEMPERATURES AGAIN. NOW FORECASTING HIGHS MAINLY IN THE 70S...WITH
UPPER 60S AT THE IMMEDIATE COAST.
STILL APPEARS MOST OF THE AREA WILL BE DRY THIS AFTERNOON PER
HRRR/RAP. HOWEVER WITH CONVECTION FIRING W OF AREA...HAVE KEPT
SLIGHT CHANCE TO CHANCE POPS THIS AFTERNOON OVER THE NW 1/2 OF THE
CWA WITH A SLIGHT CHANCE OF THUNDER. ANY THUNDERSTORMS WILL MOST
LIKELY BE ELEVATED IN NATURE AS THEY MOVE OVER THE AREA DUE TO THE
MARINE INVERSION IN PLACE...SO THE SEVERE THREAT THIS AFTERNOON IS
NIL ACROSS THE SE 1/2 OF THE CWA AND LESS THAN 5 PERCENT ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
INCREASING CONCERN THAT THE MARINE LAYER WILL NOT DISSIPATE/FRONT
LIFT TO THE N BY THIS EVENING - AND THAT THE MARINE LAYER WILL
MAINTAIN ITSELF OVER MOST IF NOT ALL THE AREA TONIGHT. WILL
CONTINUE TO MONITOR TRENDS - BUT COULD END UP MAKING SIGNIFICANT
CHANGES TO TONIGHTS FORECAST IF CURRENT TRENDS HOLD.
SCT-ISOLD SHOWERS AND TSTMS THIS EVENING. CONVECTION SHOULD BE
SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE. SHOWERS
AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS THE
UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACH THE
AREA.
HIGHS ON THURSDAY IN THE MID TO UPPER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE
EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM
SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE
COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES
AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER
THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS
AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD
RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH
MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE
ALSO TRENDED A BIT SLOWER WITH PRECIPITATION GRADUALLY TAPERING
OFF FRI AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL
NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS
DOWN EVEN FURTHER.
AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION
THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO
MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM
DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF
APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD
DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT
WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED
WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF
INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE
COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE
THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN
THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD
PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH
FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS.
AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED
HIGHER AMOUNTS.
A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD
ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO
THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES
SEVERAL DEGREES BELOW SEASONABLE LEVELS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS MORNING.
AS A RESULT...HAVE GONE MORE PESSIMISTIC WITH THE FORECAST
THROUGH THE DAY...SHOWING IMPROVEMENT IN CIGS AND VSBY GENERALLY
AROUND 17Z-21Z. HOWEVER CONFIDENCE IN THIS
IMPROVEMENT...ESPECIALLY FOR CIGS...IS LOW. POTENTIAL FOR WINDS
TO STAY LIGHTER / MORE EASTERLY FOR A LONGER PERIOD THAN INDICATED
IN TAFS AS WELL.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON...GENERALLY AT KSWF AND PERHAPS KHPN. MARINE LAYER
LIKELY TO KEEP TS AWAY FROM TERMINALS FARTHER SE.
IT COULD BE ANOTHER TRICKY NIGHT FORECASTING VFR/IFR CONDITIONS.
LATEST GUIDANCE IS HINTING AT IFR OR LESS CONDITIONS AT THE
OUTLYING TERMINALS...HOWEVER GUIDANCE DIFFERS ON TIMING AND JUST
HOW LOW CIGS AND VSBYS GET. WILL HOLD OFF IN LOWERING CONDITIONS
TOO MUCH WITH LOW CONFIDENCE HOWEVER THIS WILL NEED TO BE
MONITORED. HIGHEST CONFIDENCE OF IFR OR LOWER CONDITIONS WILL BE
AT KGON.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2
HOURS LONGER THAN INDICATED IN TAF.
KLGA FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2
HOURS LONGER THAN INDICATED IN TAF.
KEWR FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2
HOURS LONGER THAN INDICATED IN TAF.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES
SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT
17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER FOR 1-2 HOURS
LONGER THAN INDICATED IN TAF.
KHPN FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AROUND
18-21Z...ESPECIALLY FOR CIGS.
KISP FCSTER COMMENTS: LOW POTENTIAL FOR CIGS/VSBY TO IMPROVE TO
MVFR OR HIGHER LEVELS AROUND 17-18Z. WIND SPEEDS MAY BE 1-2 HOURS
SLOWER TO INCREASE THAN SHOWN IN TAF.
.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN
FOG AND STRATUS.
.SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR
WITH NW WINDS INCREASING TO 20-30KT.
.SUNDAY...VFR WITH NW WINDS 20-25KT.
&&
.MARINE...
BASED ON HRRR AND LATEST TRENDS IN OBSERVATIONS AND WEB-CAMS HAVE
EXTENDED THE DENSE FOG ADVISORY FOR THE COASTAL OCEAN ZONES...NY
HARBOR AND THE SOUTH SHORE BAYS OF LONG ISLAND THROUGH 22Z. GIVEN
NO RESTRICTIONS OF 1NM OR LESS IN VISIBILITY EVIDENT ON SOUND OR
EASTERN BAYS OF LONG ISLAND...HAVE CANCELLED THE DENSE FOG
ADVISORY THERE.
THERE SEEMS TO BE INCREASING POTENIAL FOR DENSE FOG OVER THE
SOUTHERN WATERS TO CONTINUE TONIGHT. IF TRENDS HOLD...WILL EXTEND
THE DENSE FOG ADVISORY IN TIME THROUGH TONIGHT WITH THE LATE
AFTERNOON FORECAST ISSUANCE.
SEAS ARE NOT INCREASING AS FAST AS FORECAST...SO HAVE ADJUSTED
DOWNWARD A FOOT OR SO ACROSS MOST OCEAN AREAS INTO THIS EVENING.
SEAS SLOWLY BUILD THIS AFTERNOON/EVENING TO SCA LEVELS ON THE
COASTAL OCEAN WATERS AND REMAIN ABOVE SCA LEVELS THROUGH
THURSDAY. SW FLOW INCREASES OVER THE COASTAL OCEAN WATERS TONIGHT
AS WELL WITH SFC BOUNDARY LIFTING TO NEAR THE LONG ISLAND COAST IF
NOT FARTHER N.
A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY
THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE
WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS
THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE
SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY
SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS
SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH
SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST
THE MODELS.
&&
.HYDROLOGY...
SCT SHOWERS/TSTMS THIS EVENING WILL BE CAPABLE OF PRODUCING
LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC.
TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH
LOCALLY HIGHER AMOUNTS IN TSTMS.
SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE
THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN
RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS.
THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD
RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE
LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ338-345-
350-353-355.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT
THURSDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...MALOIT/24/NV
NEAR TERM...MALOIT
SHORT TERM...MALOIT/24
LONG TERM...NV
AVIATION...BC/PICCA
MARINE...MALOIT/24/NV
HYDROLOGY...24/NV
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
600 PM CDT WED MAY 22 2013
...UPDATE TO AVIATION FOR 00Z TAFS...
.SYNOPSIS...
ISSUED AT 340 PM CDT WED MAY 22 2013
THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS
CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED
WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW
WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK
UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE
EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED MAY 22 2013
THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT
LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE
AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD
FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE
WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR
CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON
THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION
DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME
VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL
COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING.
THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN
COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW
STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT.
ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE
INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY
WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT
STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN
MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER
COULD REACH THE LOW/MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 348 PM CDT WED MAY 22 2013
LOW LEVEL MOISTURE WILL SURGE BACK TO THE NORTHWEST INTO THE
SOUTHERN PLAINS BY LATE THURSDAY AS UPPER LEVEL TROUGHING DEVELOPS
ACROSS THE WESTERN UNITED STATES. SURGE HIGH PRESSURE WILL SLIDE
SOUTHEASTWARD INTO THE MIDWEST. A WARM ADVECTION PATTERN WILL
STRENGTHEN THURSDAY NIGHT AND SOME ELEVATED THUNDERSTORM ACTIVITY
IS POSSIBLE. THE UPPER LEVEL RIDGE AXIS BETWEEN THE WESTERN AND
EASTERN UNITED STATES TROUGHS WILL BE OVER THE CENTRAL PLAINS BY
FRIDAY. BUT SOME MID LEVEL FLOW COMING THROUGH THE RIDGE WILL
ALLOW FOR LEE TROUGHING AND A SURGE OF MOISTURE FROM THE SOUTHERN
PLAINS INTO KANSAS. WESTERN KANSAS WILL BE ON THE SOUTHERN EDGE OF
THE WESTERLIES AND THE UPPER LEVEL WINDS WILL NOT BE THAT
IMPRESSIVE. HOWEVER, WITH 2000-3000 J/KG CAPE AND STRONG
DIRECTIONAL TURNING, A FEW SEVERE THUNDERSTORMS ARE POSSIBLE,
PARTICULARLY IN FAR SOUTHWEST KANSAS. HIGH TEMPERATURES FRIDAY WILL
RANGE FROM THE UPPER 70S NEAR HAYS TO THE UPPER 80S IN FAR
SOUTHWEST KANSAS CLOSER TO THE LEE TROUGH.
UPPER LEVEL TROUGHING WILL REMAIN ACROSS THE WESTERN UNITED STATES
THROUGH MID NEXT WEEK, ALTHOUGH THERE IS SOME UNCERTAINTY IN HOW
FAR EAST IT WILL PROGRESS. THE ECMWF IS LESS PROGRESSIVE THAN THE
OTHER MODELS AND GENERALLY A LESS PROGRESSIVE SOLUTION IS THE BEST
ONE. FOR SATURDAY INTO MONDAY, MODERATE TO HIGH SURFACE BASED CAPE
WILL BE IN PLACE AHEAD OF A DRYLINE. A FEW THUNDERSTORMS WILL
DEVELOP EACH DAY ALONG THE DRYLINE AND SLOWLY MOVE EASTWARD. THESE
STORMS COULD BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE
UPPER LEVEL WINDS ARE STILL NOT PROGGED TO BE THAT STRONG, SO
TORNADIC STORMS ARE NOT EXPECTED, BUT CANNOT BE RULED OUT GIVEN THE
STRONG INSTABILITY. TEMPERATURES WILL BE FAIRLY WARM THROUGH THE
EXTENDED WITH LOWS IN THE 60S AND HIGHS IN THE 80S AND 90S SINCE
KANSAS WILL BE IN THE WARM SECTOR. THE WARMEST HIGH TEMPERATURES
OUGHT TO BE IN FAR WESTERN KANSAS BEHIND THE DRYLINE AND THE
WARMEST LOWS SHOULD BE IN SOUTH CENTRAL AND CENTRAL KANSAS WHERE
DEWPOINTS AND WINDS WILL BE HIGHEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 600 PM CDT WED MAY 22 2013
LIGHT AND VARIABLE WINDS WILL EVENTUALLY BECOME NE/E 10-20 KT THROUGH
THE OVERNIGHT HOURS. THESE UPSLOPE WINDS WILL CONTINUE INTO EARLY AFTERNOON
AS WELL. STRATUS IS EXPECTED TO DEVELOP LATE TONIGHT. VFR OR MVFR CIGS
EXPECTED. ISOLATED THREAT OF TS LATE TONIGHT BUT WILL KEEP OUT OF KGCK
TAF FOR NOW DUE TO ISOLATED NATURE. BETTER CHANCE FOR THUNDERSTORMS
TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 72 58 81 / 10 20 40 30
GCK 50 71 58 83 / 10 20 30 40
EHA 52 76 59 88 / 10 30 30 40
LBL 53 74 60 87 / 10 30 30 40
HYS 47 71 56 77 / 10 20 40 40
P28 54 73 59 78 / 10 30 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
356 PM CDT WED MAY 22 2013
...UPDATED FOR LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 340 PM CDT WED MAY 22 2013
THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS
CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED
WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW
WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK
UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE
EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED MAY 22 2013
THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT
LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE
AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD
FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE
WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR
CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON
THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION
DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME
VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL
COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING.
THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN
COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW
STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT.
ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE
INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY
WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT
STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN
MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER
COULD REACH THE LOW/MID 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 348 PM CDT WED MAY 22 2013
LOW LEVEL MOISTURE WILL SURGE BACK TO THE NORTHWEST INTO THE
SOUTHERN PLAINS BY LATE THURSDAY AS UPPER LEVEL TROUGHING DEVELOPS
ACROSS THE WESTERN UNITED STATES. SURGE HIGH PRESSURE WILL SLIDE
SOUTHEASTWARD INTO THE MIDWEST. A WARM ADVECTION PATTERN WILL
STRENGTHEN THURSDAY NIGHT AND SOME ELEVATED THUNDERSTORM ACTIVITY
IS POSSIBLE. THE UPPER LEVEL RIDGE AXIS BETWEEN THE WESTERN AND
EASTERN UNITED STATES TROUGHS WILL BE OVER THE CENTRAL PLAINS BY
FRIDAY. BUT SOME MID LEVEL FLOW COMING THROUGH THE RIDGE WILL
ALLOW FOR LEE TROUGHING AND A SURGE OF MOISTURE FROM THE SOUTHERN
PLAINS INTO KANSAS. WESTERN KANSAS WILL BE ON THE SOUTHERN EDGE OF
THE WESTERLIES AND THE UPPER LEVEL WINDS WILL NOT BE THAT
IMPRESSIVE. HOWEVER, WITH 2000-3000 J/KG CAPE AND STRONG
DIRECTIONAL TURNING, A FEW SEVERE THUNDERSTORMS ARE POSSIBLE,
PARTICULARLY IN FAR SOUTHWEST KANSAS. HIGH TEMPERATURES FRIDAY WILL
RANGE FROM THE UPPER 70S NEAR HAYS TO THE UPPER 80S IN FAR
SOUTHWEST KANSAS CLOSER TO THE LEE TROUGH.
UPPER LEVEL TROUGHING WILL REMAIN ACROSS THE WESTERN UNITED STATES
THROUGH MID NEXT WEEK, ALTHOUGH THERE IS SOME UNCERTAINTY IN HOW
FAR EAST IT WILL PROGRESS. THE ECMWF IS LESS PROGRESSIVE THAN THE
OTHER MODELS AND GENERALLY A LESS PROGRESSIVE SOLUTION IS THE BEST
ONE. FOR SATURDAY INTO MONDAY, MODERATE TO HIGH SURFACE BASED CAPE
WILL BE IN PLACE AHEAD OF A DRYLINE. A FEW THUNDERSTORMS WILL
DEVELOP EACH DAY ALONG THE DRYLINE AND SLOWLY MOVE EASTWARD. THESE
STORMS COULD BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE
UPPER LEVEL WINDS ARE STILL NOT PROGGED TO BE THAT STRONG, SO
TORNADIC STORMS ARE NOT EXPECTED, BUT CANNOT BE RULED OUT GIVEN THE
STRONG INSTABILITY. TEMPERATURES WILL BE FAIRLY WARM THROUGH THE
EXTENDED WITH LOWS IN THE 60S AND HIGHS IN THE 80S AND 90S SINCE
KANSAS WILL BE IN THE WARM SECTOR. THE WARMEST HIGH TEMPERATURES
OUGHT TO BE IN FAR WESTERN KANSAS BEHIND THE DRYLINE AND THE
WARMEST LOWS SHOULD BE IN SOUTH CENTRAL AND CENTRAL KANSAS WHERE
DEWPOINTS AND WINDS WILL BE HIGHEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1237 PM CDT WED MAY 22 2013
VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS CAN BE EXPECTED
THROUGH THE AFTERNOON HOURS. A COLD FRONT IS EXPECTED TO PUSH
THROUGH WESTERN KANSAS TONIGHT. WINDS WILL SWITCH AROUND TO THE
EAST TO NORTHEAST BEHIND THE FRONT AND COULD BECOME GUSTY TO
AROUND 20-25 KNOTS AT TIMES. STRATUS IS EXPECTED TO DEVELOP LATER
TONIGHT ESPECIALLY OVER SOUTHWEST KANSAS. HAVE INTRODUCED LOW MVFR
CIGS TO GARDEN CITY AND DODGE CITY BY 10Z THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 72 58 81 / 10 20 40 30
GCK 50 71 58 83 / 10 20 30 40
EHA 52 76 59 88 / 10 30 30 40
LBL 53 74 60 87 / 10 30 30 40
HYS 47 71 56 77 / 10 20 40 40
P28 54 73 59 78 / 10 30 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...FINCH
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
343 PM CDT WED MAY 22 2013
...UPDATED SYNOPSIS AND SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 340 PM CDT WED MAY 22 2013
THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS
CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED
WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW
WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK
UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE
EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED MAY 22 2013
THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT
LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE
AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD
FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE
WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR
CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON
THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION
DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME
VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL
COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING.
THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN
COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW
STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT.
ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE
INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY
WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT
STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN
MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER
COULD REACH THE LOW/MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 415 AM CDT WED MAY 22 2013
MEDIUM RANGE MODELS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH
PRESSURE MOVING EAST INTO THE CENTRAL PLAINS THURSDAY AS A STRONG
CLOSED OFF LOW REMAINS ANCHORED ACROSS THE PACIFIC NORTHWEST. THIS
WILL SET UP A MORE DIVERGENT FLOW ALOFT ACROSS THE WESTERN HIGH
PLAINS AS A PREVAILING EASTERLY UPSLOPE FLOW CONTINUES TO SLOWLY
ADVECT MOISTURE INTO THE REGION NEAR THE SURFACE. THIS WILL BRING
THE POSSIBILITY FOR SHOWERS AND POTENTIALLY THUNDERSTORMS TO
PORTIONS OF WESTERN KANSAS THURSDAY AFTERNOON AND EVENING AS AN
UPPER LEVEL JET CORE LIFTS NORTHEAST OUT OF THE DESERT SOUTHWEST
INTO THE TEXAS PANHANDLE AND SOUTHERN KANSAS. HOWEVER, NAM AND GFS
MODEL SOUNDINGS SHOW A LACK OF SIGNIFICANT INSTABILITY, NOT TO
MENTION A POSSIBLE CAPPING ISSUE THAT COULD LIMIT THE POTENTIAL
FOR THUNDERSTORMS. STILL, UPSLOPE AND INCREASED LOW LEVEL
CONVERGENCE DUE TO A FRONTAL BOUNDARY PROJECTED TO EXTEND FROM
SOUTHEAST COLORADO INTO THE TEXAS PANHANDLE MAY SUPPORT RAIN
SHOWER DEVELOPMENT FROM THE TEXAS PANHANDLE NORTHEAST INTO
PORTIONS OF SOUTHWEST KANSAS THURSDAY WITH A SLIGHT CHANCE FOR
AN EMBEDDED THUNDERSTORM OR TWO.
THUNDERSTORM CHANCES INCREASE FRIDAY AS THE UPPER LEVEL RIDGE AXIS
SHIFTS SLIGHTLY EASTWARD WHILE SURFACE TROUGHING DEVELOPS AND
STRENGTHENS ACROSS EASTERN COLORADO HELPING TO DRAW THE FRONTAL
BOUNDARY NORTHWARD ACROSS WESTERN KANSAS. THIS WILL RESULT IN
INCREASING INSTABILITY ACROSS THE REGION BETTER SUPPORTING POTENTIAL
THUNDERSTORM DEVELOPMENT ACROSS SOUTHWEST AND CENTRAL KANSAS. THE
UPPER LEVEL PATTERN IS EXPECTED TO CHANGE VERY LITTLE THROUGHOUT
THE REMAINDER OF THE WEEKEND BRINGING A CHANCE FOR THUNDERSTORMS
TO CENTRAL AND PORTIONS OF WESTERN KANSAS EACH DAY THROUGH SUNDAY.
BELOW NORMAL TEMPERATURES ARE EXPECTED THURSDAY AS SURFACE HIGH
PRESSURE DROPS SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER
MIDWEST. THIS WILL HELP USHER SLIGHTLY COOLER AIR SOUTHWESTWARD
INTO THE WESTERN HIGH PLAINS WITH H85 TEMPERATURES JUST ABOVE 10C
ACROSS CENTRAL KANSAS TO THE MID TO UPPER TEENS(C) IN FAR SOUTHWEST
KANSAS. ALONG WITH EXPECTED INCREASING CLOUDS, LOOK FOR HIGHS ONLY
UP INTO THE 70S(F) THURSDAY AFTERNOON WITH THE COOLEST TEMPERATURES
IN CENTRAL KANSAS. A WARM FRONT IS PROJECTED TO LIFT NORTH ACROSS
WESTERN KANSAS FRIDAY AS SURFACE TROUGHING STRENGTHENS ACROSS
EASTERN COLORADO. EXPECT SLIGHTLY WARMER TEMPERATURES FRIDAY
AFTERNOON WITH HIGHS UP INTO THE MID TO UPPER 70S(F) ACROSS
CENTRAL KANSAS TO THE LOWER AND POSSIBLY THE MID 80S(F) IN EXTREME
SOUTHWEST KANSAS. THE WARMING TREND CONTINUES THROUGH THE WEEKEND
WITH WIDESPREAD 80S(F) TO NEAR 90F SATURDAY AND SUNDAY AS THE LOW
LEVEL SOUTHERLY FLOW PERSISTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1237 PM CDT WED MAY 22 2013
VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS CAN BE EXPECTED
THROUGH THE AFTERNOON HOURS. A COLD FRONT IS EXPECTED TO PUSH
THROUGH WESTERN KANSAS TONIGHT. WINDS WILL SWITCH AROUND TO THE
EAST TO NORTHEAST BEHIND THE FRONT AND COULD BECOME GUSTY TO
AROUND 20-25 KNOTS AT TIMES. STRATUS IS EXPECTED TO DEVELOP LATER
TONIGHT ESPECIALLY OVER SOUTHWEST KANSAS. HAVE INTRODUCED LOW MVFR
CIGS TO GARDEN CITY AND DODGE CITY BY 10Z THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 72 58 81 / 10 20 40 30
GCK 50 71 58 83 / 10 20 30 40
EHA 52 76 59 88 / 10 30 30 40
LBL 53 74 60 87 / 10 30 30 40
HYS 47 71 56 77 / 10 20 40 40
P28 54 73 59 78 / 10 30 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
212 PM EDT WED MAY 22 2013
.SYNOPSIS...
UPPER LEVEL IMPULSES BRINGS AN INCREASE IN SHOWERS AND
THUNDERSTORMS THROUGH THURSDAY NIGHT...UNTIL A COLD FRONT CROSSES. MUCH
COOLER WEATHER IS FORECAST THIS HOLIDAY WEEKEND UNDER HIGH
PRESSURE.
&&
.NEAR TERM /THROUGH THURSDAY/...
DAYTIME HEATING CONTINUES TO PUSH OUR TEMPERATURES CLOSE TO THE
CONVECTIVE THRESHOLD. 16Z MESOANALYSIS ILLUSTRATES NO CINH LEFT
AND EQUIV POTENTIAL TEMPS BUILDING. STILL A FAIR AMOUNT OF UNCERTAINTY
WITH THE DEVELOPMENT OF STORMS AND HOW STRONG STORMS WILL BE
LATER TODAY AND TONIGHT. LATEST THINKING IS STORMS WILL DEVELOP
ALONG THE THETA-E RIDGE AXIS WHICH IS BUILDING ACROSS WV AND WRN
PA. TERRAIN INDUCED STORMS ARE ALREADY UNDERWAY OVER THE CENTRAL
MTNS OF WV. FARTHER W ACROSS OHIO...NOT SURE HOW MUCH DEVELOPMENT
WILL OCCUR THIS AFTERNOON UNTIL S/W TROUGH PASSES AROUND 0Z.
LIKELY POPS STILL ARE ON TRACK FOR THIS EVENING FOR THE ENTIRE
AREA. IF THE LATEST HRRR IS CORRECT WE COULD SEE SOME LOCALIZED
HIGH WATER POTENTIAL OVER NRN WV WITH TRAINING OF STORMS.
AFTER MIDNIGHT THINGS SHOULD QUIET DOWN AS LLVLS STABILIZE AND WE
AWAIT MAIN TROF AXIS TO TRAVERSE FROM THE WEST. NAM AND GFS AGREE
ON A PERIOD OF DRY OR ISOLD ACTIVITY TMRW FROM LATE MRNG THROUGH
MID AFTERNOON BEFORE UPPER LEVEL IMPULSES CROSS. DO NOT FORESEE A
SEVERE WEATHER THREAT THURSDAY DUE TO LACK OF HEATING AS AN
ABUNDANCE OF CLOUDS WILL BE PRESENCE KEEPING THERMODYNAMICS LOW.
GREATEST CHALLENGE IS IF NAM SCENARIO OF A BATCH OF TSTMS RIDING
NE FROM WV INTO SWRN PA AROUND DAYBREAK MATERIALIZES. FOR
NOW...HELD OFF IN FAVOR OF CONTINUITY PER LOW CONFIDENCE ON THIS
OUTCOME. 98
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A RAPID TRANSITION TO MUCH COLDER CONDITIONS TAKES PLACE DURING
THIS PERIOD AS THE CONSENSUS OF THE MORE RELIABLE GLOBAL MODEL
SYSTEMS SUGGESTING THE MID-LEVEL SYSTEM TRACKING THROUGH THE
REGION SHOULD CLOSE OFF AS IT MOVES OVER PITTSBURGH AND SLOWLY
OOZES SOUTHEASTWARD. THE CLOSED SOLUTIONS FAVORED BY THE MORE
RELIABLE MODELS END UP TRENDING TOWARD THE SLOWER END OF THE
GUIDANCE PACK WITH THIS SYSTEM...WHICH MAKES SENSE GIVEN THE
HIGHER LONG WAVE AMPLITUDE. AS SUCH...THE SYSTEMS DEPARTURE WAS
SLOWED IN THE FORECAST WHICH RESULTED IN INCREASING POPS INTO
FRIDAY.
WHILE ITS DEPARTURE IS SLOWER...MUCH DRIER AIR DOES WORK INTO THE
AREA BY FRIDAY NIGHT WITH THE CONSENSUS OFFERING EXTREMELY LEAN
LAYER RH PROFILES AND WEAKENING NORTHWEST COLD ADVECTION. THIS
SETS THE STAGE FOR STELLAR RADIATIONAL COOLING GOING INTO SATURDAY
MORNING. GRIDDED GUIDANCE SUGGESTS WIDESPREAD 30S ACROSS THE
AREA...WHICH WITH 850 MB TEMPERATURES FALLING TOWARD -2C IS NOT TOO
SHOCKING. FROST WAS ADDED TO THE GRID TO ACCOMMODATE LOWS
GENERALLY IN THE MID 30S ACROSS VAST TRACTS OF THE CWA...AND
FROST/FREEZE HEADLINES SEEM POSSIBLE AT THIS POINT. THESE
TEMPERATURES AT 850 MB FAIL TO MODERATE DURING THE DAY SATURDAY
MUCH...SO TEMPERATURES WILL LIKELY ONLY WANDER FOR HIGHS FROM THE
UPPER 50S FRIDAY TOWARD THE LOWER 60S SATURDAY. FRIES
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SIMILAR CONDITIONS PERSIST THROUGH THE REST OF THE WEEKEND AND
EVEN POSSIBLY INTO MONDAY MORNING WITH VERY DRY CONDITIONS AND
LIGHT WINDS FAVORING SUPERIOR RADIATIONAL COOLING EACH NIGHT. AS
SUCH...LOWS CONTINUE TO LOOK TO HEAD TOWARD THE 30S EACH
NIGHT...WITH A FEW LOCATIONS INEVITABLY DROPPING BELOW FREEZING.
ONCE AGAIN...FROST WAS ADDED TO THE FORECAST INTO THE
OVERNIGHT/EARLY MORNINGS THIS WEEKEND...AND FROST/FREEZE HEADLINES
AGAIN SEEM QUITE POSSIBLE.
OTHERWISE...VERY GRADUAL MODERATION OF LOW LEVEL TEMPERATURES WILL
BE LIKELY AS THE CLOSED SYSTEM DEPARTS EASTWARD BUT DRY CYCLONIC
NORTHWESTERLY FLOW ALOFT REMAINS THE LARGE CONTROLLING FACTOR FOR
OUR WEATHER. THIS IS THANKS IN PART TO THE FACT THAT THE MODEL
CONSENSUS KEEPS THE LARGE SCALE RIDGE AXIS LARGELY TO OUR WEST
THROUGH THE MIDDLE OF NEXT WEEK. AS A RESULT...CONDITIONS SHOULD
REMAIN GENERALLY DRY WITH VERY SLOW MODERATION OF TEMPERATURES
THROUGH THE WEEK. FRIES
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
LOW TO MEDIUM CONFIDENCE FORECAST ON SHOWER AND THUNDERSTORM TIMING.
VFR WEATHER WILL PREVAIL MUCH OF THE FCST PERIOD /AT LEAST INTO
THE OVERNIGHT HOURS/...THE CHALLENGE IS TIMING ON ANY SHRA OR TSRA
IMPACTING THE TERMINALS. MAINTAINED VCTS FOR LATE AFTERNOON AND
EVENING BEFORE TRANSITIONING TO VFR SHRA UNTIL MIDNIGHT. CLOUDS
WILL DEVELOP IN THE PREDAWN HOURS...LATEST GUIDANCE SUGGEST CIGS
IN THE 015-025 WHICH IS HIGHER THAN EARLIER RUNS AND IN LINE WITH
ONGOING FORECAST. STRATOCU WILL LIFT BY MID MRNG INTO A LOW END
VFR DECK. FOR PLACES THAT EXPERIENCE RAINFALL...PATCHY FOG COULD
DEVELOP DURING THE PREDAWN HOURS. 98
.OUTLOOK.../THURSDAY THROUGH SUNDAY/...
THE PROBABILITY OF WIDESPREAD IFR WEATHER IS LOW.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
117 PM EDT WED MAY 22 2013
.SYNOPSIS...
UPPER LEVEL IMPULSES BRINGS AN INCREASE IN SHOWERS AND
THUNDERSTORMS THROUGH THURSDAY NIGHT...UNTIL A COLD FRONT CROSSES. MUCH
COOLER WEATHER IS FORECAST THIS HOLIDAY WEEKEND UNDER HIGH
PRESSURE.
&&
.NEAR TERM /THROUGH THURSDAY/...
DAYTIME HEATING CONTINUES TO PUSH OUR TEMPERATURES CLOSE TO THE
CONVECTIVE THRESHOLD. 16Z MESOANALYSIS ILLUSTRATES NO CINH LEFT
AND EQUIV POTENTIAL TEMPS BUILDING. STILL A FAIR AMOUNT OF UNCERTAINTY
WITH THE DEVELOPMENT OF STORMS AND HOW STRONG STORMS WILL BE
LATER TODAY AND TONIGHT. LATEST THINKING IS STORMS WILL DEVELOP
ALONG THE THETA-E RIDGE AXIS WHICH IS BUILDING ACROSS WV AND WRN
PA. TERRAIN INDUCED STORMS ARE ALREADY UNDERWAY OVER THE CENTRAL
MTNS OF WV. FARTHER W ACROSS OHIO...NOT SURE HOW MUCH DEVELOPMENT
WILL OCCUR THIS AFTERNOON UNTIL S/W TROUGH PASSES AROUND 0Z.
LIKELY POPS STILL ARE ON TRACK FOR THIS EVENING FOR THE ENTIRE
AREA. IF THE LATEST HRRR IS CORRECT WE COULD SEE SOME LOCALIZED
HIGH WATER POTENTIAL OVER NRN WV WITH TRAINING OF STORMS.
AFTER MIDNIGHT THINGS SHOULD QUIET DOWN AS LLVLS STABILIZE AND WE
AWAIT MAIN TROF AXIS TO TRAVERSE FROM THE WEST. NAM AND GFS AGREE
ON A PERIOD OF DRY OR ISOLD ACTIVITY TMRW FROM LATE MRNG THROUGH
MID AFTERNOON BEFORE UPPER LEVEL IMPULSES CROSS. DO NOT FORESEE A
SEVERE WEATHER THREAT THURSDAY DUE TO LACK OF HEATING AS AN
ABUNDANCE OF CLOUDS WILL BE PRESENCE KEEPING THERMODYNAMICS LOW.
GREATEST CHALLENGE IS IF NAM SCENARIO OF A BATCH OF TSTMS RIDING
NE FROM WV INTO SWRN PA AROUND DAYBREAK MATERIALIZES. FOR
NOW...HELD OFF IN FAVOR OF CONTINUITY PER LOW CONFIDENCE ON THIS
OUTCOME.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
A REINFORCING FRONT IS PROGGED FOR FRIDAY WITH RESIDUAL SHWR CHCS
FADING BY AFTN WITH PASSAGE OF THAT FEATURE. AS NW FLOW DVLPS WITH
PASSAGE OF THE AFOREMENTIONED PHASED TROF AXIS...COLD ADVCTN WL
LIMIT TEMP RECOVERY. EXPECT HIGHS ABOUT 10 DEGREES BELOW THE
SEASONAL AVERAGES UNDR THE RESULTING HIGH AMPLITUDE...ERN CONUS
TROF PTN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT ON THE OVERALL UPPER LEVEL PATTERN
THROUGH THE EXTENDED WITH AN UPPER LEVEL RIDGING OF THE CENTRAL
CONUS AND TROUGHING IN BOTH THE WEST AND EAST. WHILE THIS WOULD
GENERALLY LEAD TO A MUCH LESS THAN CONFIDENT FORECAST IN THE
SHORTWAVES WITHIN THE FLOW...THIS DOESN`T SEEM TO BE THE CASE AS
BOTH THE GFS AND ECMWF SUGGEST THAT MUCH OF THE PRECIPITATION WILL
BE SUPPRESSED SOUTH OF THE REGION THROUGH MUCH OF THE PERIOD.
THUS...OPTED TO TAKE A BLEND OF THE MODELS AND HPC
GUIDANCE. ALSO...HEDGED A BIT COOLER WITH TEMPERATURES WITH
NORTHWEST FLOW PRESENT ESPECIALLY FOR THE FIRST HALF OF THE
PERIOD. THIS KEPT TEMPERATURES BELOW SEASONAL AVERAGES SAT/SUN
BEFORE MODERATING CLOSER TO NORMAL FOR THE REST OF THE PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
LOW TO MEDIUM CONFIDENCE FORECAST ON SHOWER AND THUNDERSTORM TIMING.
VFR WEATHER WILL PREVAIL MUCH OF THE FCST PERIOD /AT LEAST INTO
THE OVERNIGHT HOURS/...THE CHALLENGE IS TIMING ON ANY SHRA OR TSRA
IMPACTING THE TERMINALS. MAINTAINED VCTS FOR LATE AFTERNOON AND
EVENING BEFORE TRANSITIONING TO VFR SHRA UNTIL MIDNIGHT. CLOUDS
WILL DEVELOP IN THE PREDAWN HOURS...LATEST GUIDANCE SUGGEST CIGS
IN THE 015-025 WHICH IS HIGHER THAN EARLIER RUNS AND IN LINE WITH
ONGOING FORECAST. STRATOCU WILL LIFT BY MID MRNG INTO A LOW END
VFR DECK. FOR PLACES THAT EXPERIENCE RAINFALL...PATCHY FOG COULD
DEVELOP DURING THE PREDAWN HOURS.
.OUTLOOK.../THURSDAY THROUGH SUNDAY/...
THE PROBABILITY OF WIDESPREAD IFR WEATHER IS LOW.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...98
NEAR TERM...98
SHORT TERM...15
AVIATION...98
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EDT WED MAY 22 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 353 PM EDT WED MAY 22 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLUGGISH UPR LO
OVER THE UPR MS RIVER VALLEY BTWN RDG OFF THE SE CONUS AND ANOTHER
RDG AXIS OVER THE ROCKIES. BAND OF -SHRA STRETCHING FM NE MN INTO
THE WRN CWA UNDER BAND OF H85-7 FGEN TO THE NE OF THE CLOSED LO IS
HOLDING FIRM EVEN THOUGH LLVL DRY AIR IS SURGING INTO NE MN/WRN LK
SUP IN STEADY NE FLOW BTWN HI PRES OVER NRN MANITOBA AND SFC LO PRES
IN THE LOWER LKS. ANOTHER LARGER AREA OF SHRA/ISOLD TS OVER THE SE
HALF OF WI/S HALF OF LK MI IS EXPANDING TO THE N AS SHRTWV OVER
IL/LEFT EXIT REGION OF SUPPORTING H3 JET MAX IS MOVING N OF THE
CLOSED LO. OTRW...LO CLDS HAVE BEEN QUITE PERSISTENT OVER UPR MI
WITH CHILLY NE WIND OFF LK SUP. SOME FOG HAS PERSISTED AS WELL NEAR
LK SUP E OF THE KEWEENAW...WHERE THE LLVL DRY AIR HAS NOT YET
ARRIVED.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE HOW DRIER AIR ARRIVING
FM THE N WL IMPACT POPS ASSOCIATED WITH BAND OF FGEN OVER THE WRN
ZNS AND AREA OF SHRA MOVING N TOWARD THE SE COUNTIES.
TNGT...UPR LO NOW OVER SE MN IS PROGGED TO DRIFT ESE...AND NAM SHOWS
BAND OF H85-7 FGEN/H85-5 QVECTOR CNVGC FOLLOWING THIS FEATURE SEWD
ACRS MAINLY THE W HALF OF THE CWA. AT THE SAME TIME...H7-3 QVECTOR
CNVGC/UPR DVGC IN LEFT EXIT AHEAD OF SHRTWV/SUPPORTING UPR JET
LIFTING NNEWD WL IMPACT MAINLY THE SE COUNTIES. LOOKS LIKE THESE
DYNAMICS MAY INTERACT FOR A TIME LATE THIS AFTN/EARLY EVNG OVER THE
SE ZNS. SO HIER POPS IN THIS AREA AT THAT TIME SEEM APPROPRIATE. AT
THE SAME TIME...DRIER AIR SURGING INTO THE NW CWA UNDER STRONGER NNE
FLOW WL END ANY LINGERING PCPN AS FGEN AXIS SHIFTS TO THE SE. THE
PCPN WL END EVEN OVER THE SE ZNS AFT 06Z FOLLOWING DEPARTURE OF
SHRTWV/ACCOMPANYING DYNAMICS AND ARRIVAL OF DRIER LLVL AIR. THE
ARRIVAL OF THE DRIER LLVL AIR AND EXIT OF THE DYNAMICS WL ALLOW FOR
SOME CLRG...BUT THE UPSLOPE NNE FLOW MAY SLOW THE PROCESS OVER THE
HIER TERRAIN NEAR LK SUP.
THU...HI PRES IS FCST TO BLD INTO THE UPR LKS...RESULTING IN DRY WX.
ALTHOUGH LINGERING H85 THERMAL TROF WITH TEMPS ARND 0C THRU 00Z
WOULD INDICATE QUITE A BIT OF DIURNAL CU/SC AT THIS TIME OF YEAR
OVER LAND...DRYNESS OF INCOMING AIRMASS AS WELL AS LLVL ACYC/
DIFFLUENT FLOW WL RESULT IN MOCLR SKIES. IF THERE IS ANY UPSLOPE SC
OVER THE HIER TERRAIN NEAR LK SUP...THIS CLD WL MIX OUT EARLY. THE
FCST H85 TEMPS AND MIXING TO H8-85 ON NAM FCST SDNGS YIELDS HI TEMPS
TOPPING OUT IN THE 50S OVER THE INTERIOR. BUT STIFF NNE WIND OFF LK
SUP WL CAUSE TEMPS TO HOLD IN THE 40S NEAR THE BIG LAKE. THESE
STRONGER NE WINDS WL DIMINISH OVER THE W IN THE AFTN WITH THE APRCH
OF THE HI CENTER/WEAKENING PRES GRADIENT.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 353 PM EDT WED MAY 22 2013
SLOW MOVING AND RATHER STABLE UPPER AIR PATTERN EXPECTED THROUGH THE
ENTIRE LENGTH OF THE LONG TERM. INITIALLY LATE THIS WEEK...THERE IS
A TROUGH OVER PACIFIC NORTHWEST WITH RIDGING OVER CENTRAL CONUS...
AND TROUGHING OVER MUCH OF EASTERN CANADA ACROSS THE GREAT LAKES.
EXPECT BELOW NORMAL TEMPERATURES TO PREVAIL THROUGH THE HOLIDAY
WEEKEND AS THE TROUGH ONLY SLOWLY MOVES TO THE EAST. EVENTUALLY...
WARMER TEMPERATURES ARE EXPECTED BY MIDDLE OF NEXT WEEK WHEN RIDGING
EXPANDS FROM PLAINS ACROSS THE GREAT LAKES. AFTER AN UNSETTLED AND
WET WEEK THAT HAS OCCURRED OVER THE UPPER GREAT LAKES...HUDSON BAY
HIGH PRESSURE RIDGING ACROSS THE GREAT LAKES SHOULD BRING A
PROLONGED PERIOD OF DRY WEATHER INTO NEXT WEEK. CERTAINLY POSSIBLE
THIS DRY WEATHER STRETCH MAY EVEN PERSIST INTO THE MIDDLE OF NEXT
WEEK. WARM FRONT FORMING TO THE SOUTH AND WEST OF UPPER MICHIGAN
WILL RESULT IN SOME SMALLER CHANCES OF PRECIP BY NEXT WEDNESDAY...
BUT GIVEN THE VERY DRY AIRMASS IN PLACE...GREATEST CHANCE OF SHOWERS
AND STORMS WILL LIKELY STAY TO WEST OF UPPER LAKES CLOSER TO AXIS OF
HIGHER H85-H7 MOISTURE AND INSTABILITY.
GUSTY WINDS AROUND ON THURSDAY DIMINISH BY THE WEEKEND AS HIGH
PRESSURE BUILDING SOUTH OUT OF NORTHERN ONTARIO BECOMES MORE
ESTABLISHED. LIGHTER WINDS ON THURSDAY NIGHT AND VERY DRY AIRMASS
OVERHEAD DUE TO STRONG MIXING EARLIER IN THE DAY WILL SUPPORT MIN
TEMPS DROPPING TO AROUND 20 DEGREES INTERIOR WEST AND IN THE 20S TO
LOWER 30S ELSEWHERE. EXPECT WIDESPREAD FROST FOR MANY AREAS ON
THURSDAY NIGHT. WE DO NOT OFFICIALLY BEGIN THE FROST AND FREEZE
HEADLINES UNTIL MEMORIAL DAY BUT WILL CONTINUE TO INCLUDE MENTION IN
THE GRIDS. WITH STRONG HIGH PRESSURE OVER THE AREA...NEAR 1030MB...
LAKE BREEZES MAY GET GUSTY AT TIMES THIS WEEKEND. AFTER A COOLER DAY
ALL AREAS ON FRIDAY...COOLING WILL BECOME MORE OF A LAKESIDE FEATURE
THROUGH THE WEEKEND AS INLAND AREAS RISE INTO THE 60S.
SEEMS THERE IS A SLIM CHANCE OF LGT RAIN/SPRINKLES OVER FAR WEST
CWA LATE FRIDAY NIGHT INTO SATURDAY MORNING. 12Z NAM SOUNDINGS SHOW
MOISTURE IN MID LEVELS ENHANCED BY RIGHT ENTRANCE REGION OF
DEPARTING JET STREAK OVER ONTARIO BUILDING DOWN ENOUGH ALONG WITH
SUFFICIENT UVM TO RESULT IN BAND OF LGT SHRA MAKING IT INTO IWD
06Z-12Z ON SATURDAY. ECMWF/GFS SHOW SOME MID LEVEL MOISTURE BUT HAVE
QPF STAYING OUT OF CWA. 12Z ECMWF DOES SHOW A BIT NOW THOUGH. NAM
SEEMS TOO AGGRESSIVE WITH EASTWARD PUSH OF LGT PRECIP SO WILL NOT
PUT A MENTION IN YET. INCREASE IN CLOUDS OVERNIGHT WILL IMPACT MIN
TEMPS AND MAY RESTRICT POTENTIAL FOR FROST...AT LEAST IN THE
INTERIOR WEST CWA. ELSEWHERE...TEMPS DROPPING INTO THE UPPER 20S OR
NEAR 30 DEGREES WILL SUPPORT MORE FROST...ESPECIALLY INLAND FROM THE
LAKES. IF THERE ARE BKN CLOUDS WEST...THEY SHOULD DISSIPATE BY
SATURDAY EVENING RESULTING IN ANOTHER COOL NIGHT WITH SOME FROST
INLAND FROM THE GREAT LAKES SHORES.
DUE TO COOL AND DAMP WEATHER AND MODERATE RAIN AMOUNTS IN SOME AREAS
/HAD REPORT TODAY OF OVER 4 INCHES TO WEST OF ONTONAGON/...FIRE
WEATHER ISSUES ARE TAKING A BRIEF HIATUS. EVENTUALLY DUE TO ALMOST A
WEEK OF DRYING...INCREASING SOUTH/SOUTHWEST WINDS...AND WARMER
TEMPERATURES INTO THE 70S EARLY-MID NEXT WEEK MAY SEE INCREASING
FIRE WEATHER CONCERNS FOR AREAS THAT HAVE NOT EXPERIENCED A FULL
GREEN UP AND/OR SEEN A LOT OF RAIN OVER THE LAST FEW DAYS. &&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 123 PM EDT WED MAY 22 2013
AS A STEADY NNE WIND BTWN HI PRES IN SCENTRAL CANADA AND LO PRES
OVER THE LWR GRT LKS ADVECTS MUCH DRIER LLVL AIR OVER UPR MI...
EXPECT IMPROVING CONDITIONS TO VFR THIS EVNG. CMX WL BE CLOSER TO
THE INCOMING DRIER AIR AND SEE A QUICKER IMPROVEMENT THAN AT IWD/
SAW...WHERE A MORE SGNFT UPSLOPE WIND COMPONENT WL ALSO SLOW THE
TREND TOWARD VFR. UNDER A TIGHTENING PRES GRADIENT...EXPECT GUSTY
NNE WINDS AT ALL 3 SITES TNGT/THU MRNG.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 353 PM EDT WED MAY 22 2013
EXPECT INCREASING NE WINDS UP TO 25-30 KTS UNDER SHARPENING PRES
GRADIENT IN ADVANCE OF HI PRES BUILDING TOWARD LAKE SUP THRU
TONIGHT. THIS STRENGTHENING FLOW WILL ADVECT DRIER AIR OVER THE
LAKE...SO LINGERING FOG SHOULD DISSIPATE THIS EVENING. BASED ON
CURRENT VISIBILITY REPORTS/WEBCAM IMAGERY NEAR THE LAKE...OPTED TO
CANX GOING DENSE FOG ADVISORIES THAT WERE SET TO EXPIRE AT 21Z.
CLOSER APPROACH OF HI PRES/WEAKER PRES GRADIENT WILL RESULT IN
SLOWLY DIMINISHING WINDS W TO E ON THU. AS HIGH PRESSURE CONTINUES TO
SPREAD ACROSS THE UPPER GREAT LAKES THROUGH THE WEEKEND...EXPECT
WINDS LESS THAN 20 KTS ON LAKE SUPERIOR. LIGHTER WINDS WILL CONTINUE
INTO EARLY NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ221-248-
250.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1248 PM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 625 AM CDT WED MAY 22 2013
AS DISCUSSED EARLIER...ENDED UP MAKING A FEW ADJUSTMENTS TO VERY
SHORT TERM GRIDS BASED ON LATEST RADAR TRENDS...AND WITH SUPPORT
FROM THE LATEST RAP13/HRRR QPF/REFLECTIVITY. ALTHOUGH CANNOT RULE
OUT A FEW SPOTS REPORTING LIGHT MEASURABLE RAIN WITH THIS
ACTIVITY...ESPECIALLY IN THE NANCE/POLK COUNTY AREA...THINK THAT
NON-MEASURABLE SPRINKLES WILL BE THE DOMINANT STORY FOR MOST OF
THE AFFECTED AREA...AND THUS LEFT OUT A MEASURABLE POP.
HOWEVER...BEEFED UP SPRINKLE WORDING TO WIDESPREAD IN SEVERAL FAR
NORTHEAST COUNTIES THROUGH NOON 17Z...AND EXPANDED AN ISOLATED
SPRINKLE MENTION AS FAR SOUTH AS A LOUP CITY-GENEVA LINE. IT MAY
TURN OUT THAT THIS LIGHT PRECIP MAY BE OUT OF THE PICTURE WELL
BEFORE NOON...BUT GIVEN THE VERY SLOW MOVING NATURE OF THE PARENT
MID LEVEL LOW TO THE EAST ANYTHING IS POSSIBLE. ALSO BEEFED UP SKY
COVER PERCENTAGES FROM MOSTLY CLOUDY TO OUTRIGHT CLOUDY ACROSS
ROUGHLY THE NORTHEAST 1/2 OF THE CWA THROUGH MID-DAY...WHILE
LEAVING A MORE OPTIMISTIC TREND IN PLACE FARTHER SOUTHWEST. THE
LATEST HRRR IS NOW SPORTING A ROUGHLY 20 DEGREE HIGH-TEMP GRADIENT
ACROSS THE CWA THIS AFTERNOON FROM ONLY LOW-MID 50S NORTHEAST TO
MID 70S SOUTHWEST. OTHER SHORT TERM MODELS SUCH AS THE RAP13 ARE
NOT AS COOL IN THE NORTHEAST AS THE HRRR...AND THUS WILL RESIST
THE URGE TO MODIFY AFTERNOON HIGHS AT THIS TIME...BUT FOR SURE ITS
POSSIBLE THAT SOME NORTHEAST AREAS COULD STRUGGLE TO REACH THE
MID-UPPER 50S AND NEXT SHIFT WILL HAVE MONITOR TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM CDT WED MAY 22 2013
WHILE THERE IS CERTAINLY NO HIGH-IMPACT WEATHER DURING THE NEXT
24 HOURS...THERE ARE AT LEAST A FEW TRICKY ELEMENTS AT
HAND...INCLUDING THE EXTENT OF LOW STRATUS AND ITS POSSIBLE
INFLUENCE ON A FAIRLY DECENT SOUTHWEST-NORTHEAST TEMP
GRADIENT...AND ALSO THE EXTENT OF SPRINKLES/LIGHT RAIN SHOWERS
MAINLY THIS MORNING IN THE NORTHEAST.
08Z OBJECTIVE SURFACE ANALYSIS REVEALS NO MAJOR FEATURES ACROSS
THE CENTRAL PLAINS...WITH THE CWA POSITIONED BETWEEN A MODEST 1004
MILLIBAR LOW OVER EASTERN IA...AND A 1014MB HIGH OVER THE NEB
PANHANDLE...A SOUTHWARD EXTENSION OF A STRONGER...BROADER HIGH
WELL TO THE NORTH IN CANADA. WITHIN THE MODEST PRESSURE GRADIENT
BETWEEN THESE FEATURES...A FAIRLY STEADY NORTH-NORTHWEST BREEZE OF
10-15 MPH HAS PREVAILED THROUGH THE NIGH IN MOST AREAS...WITH
OCCASIONAL GUSTS OVER 20 MPH. TEMPERATURES WILL START OUT THE
MORNING SEASONABLY COOL...WITH EVENTUAL LOWS AIMED INTO THE MID-
UPPER 40S ALL AREAS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM
MODEL DATA FEATURES A CLOSED 500MB LOW DRIFTING SLOWLY
EAST...CENTERED NEAR THE IA/SD/NEB BORDER...AND A FAIRLY SHARP MID
LEVEL TROUGH AXIS THEN TRAILING SOUTH-SOUTHEAST INTO THE MID-SOUTH
STATES. OFF TO THE WEST OF THE LOCAL AREA...A LOW AMPLITUDE MID
LEVEL RIDGE IS ALIGNED NORTH-SOUTH THROUGH THE ROCKIES...WITH A
FAIRLY VIGOROUS...EXPANSIVE CLOSED LOW SPINNING OVER THE PACIFIC
NORTHWEST. WHILE IT HAS TAKEN ITS TIME FORMING...11-3.9 MICRON
SATELLITE IMAGERY AND AUTOMATED OBS HAVE FINALLY REVEALED THE
FORMATION OF FAIRLY WIDESPREAD LOW STRATUS MAINLY IN THE 1500-2500
FT RANGE OVER MUCH OF THE CWA...ALTHOUGH SOME BREAKS IN THE CLOUDS
DO STILL EXIST. ALSO JUST WITHIN THE PAST 90 MINUTES OR SO...AN
INCREASING FLARE-UP OF LIGHT RAIN/SPRINKLES HAS TAKEN PLACE MAINLY
OVER THE FAR NORTHERN/NORTHEAST CWA...WITH UPSTREAM OBS AT PLACES
SUCH AS ONEILL AND ALBION CONFIRMING AT LEAST TRACE AMOUNTS ARE
FALLING.
TODAY...THE MAIN STORY ALOFT INVOLVES THE CONTINUED SLOW DEPARTURE
OF THE CLOSED MID LEVEL LOW...WITH THE CENTER OF THIS FEATURE
PROGGED TO ONLY REACH NORTHEAST IA BY 00Z. AT THE SURFACE...A
MODEST PRESSURE GRADIENT WILL REMAIN IN PLACE AS HIGH PRESSURE TO
THE NORTH NOSES SOUTHWARD...AND THIS IN COMBINATION WITH MIXING TO
AT LEAST 850MB IN MOST AREAS WILL RESULT IN SOMEWHAT BREEZY
CONDITIONS ESPECIALLY WITHIN THE NORTHEAST 2/3 OF THE CWA...WITH
SUSTAINED NORTHWEST WINDS 15 TO POSSIBLY 20 MPH...AND SOME HIGHER
GUSTS. THE REAL CHALLENGE TODAY LIES INITIALLY WITH THE EXTENT AND
INTENSITY OF RAINFALL...AND ALSO JUST HOW STUBBORN THE LOW STRATUS
DECK WILL BE...AND WHETHER OR NOT IT RETREATS SLOW NORTHEAST
DURING THE AFTERNOON. STARTING OUT EARLY THIS MORNING THROUGH MID-
DAY...HAVE INTRODUCED A MENTION OF SPRINKLES TO A PREVIOUSLY
PRECIP-FREE FORECAST FOR FAR NORTHEAST AREAS MAINLY NORTH OF A
GREELEY-POLK LINE...AS DECENT LOW-MID LEVEL SATURATION UP TO
AROUND 600MB RESIDES MAINLY IN THIS ZONE AND POINTS
NORTHEAST...ASSOCIATED WITH A BATCH OF MID LEVEL MOISTURE FOCUSED
IN THE DEFORMATION ZONE ON THE BACK-SIDE OF THE DEPARTING LOW. THE
VERY SHORT TERM QUESTION THAT WILL NEED PONDERED OVER THE NEXT FEW
HOURS IS WHETHER TO EXPAND THIS SPRINKLE MENTION SOUTHWESTWARD
CLOSER TO I-80 PER SUGGESTION OF THE LATEST HRRR REFLECTIVITY
PROG...AND ALSO WHETHER TO UP THE ANTE TO A MEASURABLE POP. WILL
GIVE IT SOME TIME TO SEE IF AREA OBSERVATIONS SUPPORT A FEW
HUNDREDTHS OF ACCUMULATIONS BEFORE POSSIBLY MAKING THIS MOVE. AT
ANY RATE...ANY LIGHT RAINFALL IN THE NORTHEAST...ESPECIALLY OF THE
POTENTIALLY MEASURABLE VARIETY...IS EXPECTED TO BE OUT OF THE
PICTURE BY NOON...AS THE MID LEVELS START TO DRY OUT FROM WEST TO
EAST. CLOUD-WISE...HAVE LEANED TOWARD A COMBINATION OF THE NAM AND
HRRR...WITH THE EXPECTATION OF A RATHER SHARP SOUTHWEST-NORTHEAST
GRADIENT RANGING FROM MOSTLY SUNNY-PARTLY CLOUDY SOUTHWEST TO
MOSTLY CLOUDY AT BEST IN THE NORTHEAST. SHAKY CONFIDENCE IN THESE
CLOUD DETAILS LEAD TO SOMEWHAT SHAKY CONFIDENCE IN HIGH TEMPS. AT
LEAST FOR NOW...NUDGED SOUTHWEST AREAS UP A FEW DEGREES AND
NORTHEAST AREAS DOWN A FEW DEGREES VERSUS PREVIOUS...WHILE LEAVING
THE CENTRAL RATHER UNCHANGED. AS A RESULT...AM AIMING FROM UPPER
50S-LOW 60S FAR NORTH/NORTHEAST TO MID 60S TRI-CITIES TO MID 70S
SOUTHWEST. HOWEVER...AM STARTING TO WONDER IF THE HRRR MIGHT BE
ONTO SOMETHING...KEEPING MUCH OF THE NORTHEAST 1/2 OF THE CWA WELL
DOWN IN THE MID-50S AT BEST UNDER THE LONGEST-LASTING STRATUS.
THIS WILL BEAR WATCHING FOR LATER UPDATES...BUT DON/T WANT TO GO
QUITE THIS COOL YET.
TURNING TO THE TONIGHT PERIOD...00Z-12Z...CONFIDENCE REMAINS
RATHER HIGH IN A LEGITIMATELY DRY NIGHT...WITH THE SOLE POSSIBLE
EXCEPTION OF SOME PATCHY LIGHT DRIZZLE IN THE EVENING IN THE NORTH
UNDER A LOW STRATUS DECK...BUT THIS SCENARIO IS TOO UNCERTAIN TO
INSERT AT THIS TIME. IN THE MID-UPPER LEVELS...THE DEPARTING LOW
FINALLY SLIPS FAR ENOUGH EAST TO ALLOW THE RIDGE TO THE WEST TO
START BUILDING INTO NEB/KS. ALTHOUGH THERE WILL BE A MODEST
NORTHWEST-SOUTHEAST ORIENTED WING OF MID LEVEL MOISTURE
ADVECTION/ISENTROPIC LIFT THAT SETS UP FROM SOUTHWEST NEB TO
SOUTHEAST KS MAINLY AFTER MIDNIGHT AS EVIDENT ON THE 310K
SURFACE...SOUNDINGS SUGGEST THAT LIFT/MOISTURE SHOULD BE
INSUFFICIENT FOR PRECIP OVER THE CWA...ALTHOUGH A FEW SHOWERS OR
EVEN WEAK STORMS COULD FLARE UP WITHIN A FEW COUNTIES JUST TO THE
SOUTH/SOUTHWEST BY SUNRISE. AT THE SURFACE...HIGH PRESSURE WILL
CONTINUE OOZING DOWN FROM THE NORTH...KEEPING FAIRLY LIGHT BUT
STEADY NORTHERLY BREEZES AROUND 10 MPH IN PLACE. DESPITE THE
PRESENCE OF POTENTIALLY DECENT LOW LEVEL SATURATION...THESE
BREEZES SHOULD KEEP ANYTHING MORE THAN HAZE/LIGHT FOG AT BAY. THE
REAL QUESTION MARK AT THIS POINT TONIGHT AGAIN LIES WITH LOW
STRATUS TRENDS. WHILE THE PREVIOUS FORECAST HAD NO WORSE THAN
PARTLY CLOUDY SKIES...THE LATEST NAM RUNS AND ASSOCIATED MET
GUIDANCE FAIRLY AGGRESSIVELY BRING A BATCH OF LOW STRATUS BACK
SOUTHWARD ACROSS MOST OF THE CWA AS THE NIGHT WEARS ON...WITH THIS
ESPECIALLY EVIDENT AT 900MB. FOR NOW...HAVE STARTED AN UPWARD
TREND IN SKY COVER...BUT VERY WELL MAY NOT BE HIGH ENOUGH
ESPECIALLY POST-MIDNIGHT. EVEN IF STRATUS DOES END UP BEING MORE
WIDESPREAD THAN CURRENTLY SUGGESTED...CONFIDENCE IS DECENT THAT
LOW TEMPS WILL END UP SIMILAR TO THOSE OF THIS MORNING...AND USED
A BLEND OF MET/MAV GUIDANCE...AIMING FOR ANOTHER COOL ONE WITH MID
40S MOST SPOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 509 AM CDT WED MAY 22 2013
MODELS ARE IN GOOD AGREEMENT TRANSITIONING A RIDGE OF HIGH PRESSURE
ACROSS THE PLAINS ON THURSDAY IN WAKE OF THE DEPARTING UPPER LEVEL
LOW. WHILE HEIGHTS ALOFT WILL BE RISING...EXPECT ONLY A MODESTLY
WARMER AFTERNOON ON THURSDAY AS 850MB TEMPS ARE EXPECTED TO ONLY
REBOUND A COUPLE OF DEGREES AND PLENTY OF CLOUD COVER IS EXPECTED IN
EASTERLY UPSLOPE FLOW.
AS THE WINDS SHIFT MORE SOUTHEASTERLY THURSDAY NIGHT AND
FRIDAY...EXPECT ADDITIONAL MOISTURE TO SURGE NORTHWARD...AND FOR
INCREASING INSTABILITY ACROSS THE REGION. THIS BUILDING INSTABILITY
COMBINED WITH SOME FORCING FROM THE LOW LEVEL JET...WILL LIKELY
RESULT IN A CHANCE OF THUNDERSTORMS THURSDAY NIGHT ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA...WHICH WILL BE IN CLOSER
PROXIMITY TO THE JET. WITH THE NOSE OF THE NOCTURNAL JET MORE
FOCUSED ACROSS THE HEART OF LOCAL AREA FRIDAY AND FRIDAY
NIGHT...CANNOT RULE OUT ADDITIONAL ELEVATED SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCES FOR
PRECIPITATION COMING DURING THE LATE EVENING AND OVERNIGHT HOURS.
THEREAFTER THE MID LEVEL CAP IS EXPECTED TO WEAKEN SUBSTANTIALLY BY
SATURDAY AFTERNOON... AND WITH SEVERAL THOUSAND JOULES OF CAPE TO
WORK WITH THROUGH THE REMAINDER OF THE LONG TERM PERIODS...WILL
LIKELY SEE THUNDERSTORMS AROUND EACH DAY AS PERIODIC VORTICITY
MAXIMA EJECT OUT OF THE LONGWAVE TROUGH ACROSS THE WEST COAST.
ADDITIONALLY...WITH THESE SUBSTANTIAL CAPE VALUES AND MARGINALLY
SUPPORTIVE SHEAR PROFILES...WILL HAVE THE POTENTIAL FOR SOME SEVERE
THUNDERSTORMS DEVELOP FROM TIME TO TIME SATURDAY ONWARD...WITH LARGE
HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY THREATS.
TEMPERATURES THROUGH THE PERIOD ARE NOT EXPECTED TO FLUCTUATE A
WHOLE LOT AS THERE WILL BE LITTLE CHANGE IN THE UNDERLYING AIRMASS
SATURDAY ONWARD...WITH LOWER TO MIDDLE 80S EXPECTED EACH AFTERNOON
AND LOWER 60S EXPECTED AT NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1248 PM CDT WED MAY 22 2013
MVFR CONDITIONS FORECAST THROUGH 20Z...VFR 20-02Z...THEN MVFR
CONDITIONS 02-15Z.
AS OF MIDDAY A STRATUS DECK...WITH A CEILING NEAR 2000FT
AGL...PERSISTS AT KGRI. THIS CEILING IS EXPECTED TO CONTINUE
THROUGH ANOTHER COUPLE HOURS...BUT IS THEN EXPECTED TO SCATTER OUT
BY MID AFTERNOON...THUS THE VFR FORECAST BEGINNING 20Z. VFR
CONDITIONS ARE THEN FORECAST THROUGH THIS EVENING...HOWEVER
GUIDANCE SUGGESTS AN MVFR DECK WILL ONCE AGAIN INFILTRATE THE AREA
THIS EVENING AND INTO THE OVERNIGHT HOURS. IT IS WORTH NOTING THAT
SOME GUIDANCE SUGGESTS IFR CEILINGS...OR LOWER...WILL BE REALIZED
TONIGHT THROUGH EARLY THURSDAY MORNING...BUT AT THIS TIME
CONFIDENCE IS NOT HIGH ENOUGH TO INSERT SUCH CONDITIONS IN THE
TAF. FUTURE SHIFTS WILL WANT TO CONTINUE MONITORING FOR THE
POSSIBLE INSERTION OF A LOWER CEILING IN FUTURE TAFS. WHAT CEILING
DOES DEVELOP OVERNIGHT TONIGHT SHOULD SCATTER OUT POST- SUNRISE
THURSDAY. THE SURFACE WIND WILL TRANSITION FROM THE NORTHWEST TO
MORE OF A NORTH/NORTHEAST DIRECTION THROUGH THE NEXT 24
HOURS...SUSTAINED AT AROUND 14KTS AND GUSTING NEAR 20KTS THROUGH
THIS EVENING. VISIBILITY RESTRICTION IS NOT CURRENTLY EXPECTED AT
KGRI THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...PFANNKUCH
LONG TERM...SAR
AVIATION...BRYANT/BRUM
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
125 PM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 125 PM CDT WED MAY 22 2013
CONFINED REMAINING POPS THIS AFTERNOON ALONG AND SOUTHEAST OF A
LINE FROM FORMAN TO WAHPETON TO WADENA. LOW STRATUS AND LINGERING
LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE SOUTH AND EAST AS THE
RESPONSIBLE SURFACE LOW SLIDES INTO NORTHERN ILLINOIS. ADJUSTED
SKY AND AND TEMPERATURE GRIDS TO MATCH LATEST OBSERVATIONAL
TRENDS. OTHERWISE...NO MAJOR CHANGES TO THIS FORECAST.
UPDATE ISSUED AT 1024 AM CDT WED MAY 22 2013
NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE AS THE INHERITED
FORECAST IS ON TRACK AND BLENDED TO 15 UTC OBSERVED TRENDS. GIVEN
RADAR AND SURFACE OBSERVATIONS...DID INCREASE POPS TO NEAR 100
FOR THIS MORNING ACROSS LAKES COUNTRY...DECREASING THROUGH THE
AFTERNOON WITH THE CWA EXPECTED TO BE PRECIPITATION FREE BY 22-00
UTC. THE RAP HAS PERFORMED WELL IN REGARDS TO THE STRATUS SHIELD
THE PAST COUPLE OF DAYS AND FOLLOWED ITS LATEST 14 UTC SOLUTION
FOR CLOUD COVER.
UPDATE ISSUED AT 647 AM CDT WED MAY 22 2013
NORTH TO NORTHEASTERLY WINDS PICKING UP HAVE SCOURED OUT THE FOG
THAT WAS STARTING TO FORM OVER OUR NORTHWESTERN COUNTIES...SO
REMOVED MENTION FOR THE REST OF THE MORNING. RAIN WILL LINGER OVER
THE SOUTHEASTERN COUNTIES FOR A WHILE LONGER THIS MORNING BEFORE
DRYING OUT THIS AFTERNOON. CLOUDS WILL DECREASE THROUGHOUT THE
DAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 330 AM CDT WED MAY 22 2013
UPPER LOW FINALLY BEGINNING TO PULL AWAY FROM THE CWA AS IT WILL
SLOWLY MOVE SOUTHEASTWARD INTO IA TODAY. SFC HIGH PRESSURE HAS
STARTED TO NOSE DOWN OUT OF CANADA INTO THE NORTHERN PLAINS. MOST
OF THE PRECIP HAS MOVED SOUTH OF THE AREA ALTHOUGH A FEW SCATTERED
SHOWERS STILL LINGER IN THE SOUTHERN COUNTIES. THE NORTH HAS
CLEARED OUT COMPLETELY AND THERE HAS BEEN SOME PATCHY FOG
FORMATION AROUND CANDO AND LANGDON. HOWEVER...THERE IS STILL A
PRESSURE GRADIENT AND THINK THIS WILL KEEP FOG FROM BECOMING
WIDESPREAD AND DENSE. WILL KEEP A CLOSE EYE ON OBS THROUGH THE
EARLY MORNING HOURS.
SHOWERS AND CLOUDS WILL LINGER OVER THE SOUTHERN COUNTIES FOR MUCH
OF THE DAY BEFORE FINALLY CLEARING OUT BY LATE AFTERNOON. THIS
WILL KEEP TEMPS COOLER AND AROUND 60 WHILE THE NORTH WILL BE A BIT
WARMER. THE SFC HIGH WILL MOVE FURTHER DOWN FROM CANADA INTO THE
UPPER MS VALLEY TONIGHT. THIS SHOULD HELP THE NORTHER TIER ALONG WITH
EASTERN COUNTIES GET DOWN TO BELOW 40 DEGREES IN SOME AREAS.
THURSDAY SHOULD BE QUIET AND A BIT WARMER AS UPPER RIDGING BUILDS
OVER THE REGION. WITH SOME DECENT SUNSHINE KEPT HIGHS IN THE 60S
TO LOW 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM CDT WED MAY 22 2013
THURSDAY NIGHT SOUTHEASTERLY WINDS STILL START PICKING UP OVER THE
WESTERN COUNTIES AS SFC HIGH PRESSURE OVER MN/WI ALONG WITH A
DEVELOPING LOW OVER MT CREATES A DECENT PRESSURE GRADIENT. THE
WINDS WILL HELP KEEP THE WESTERN COUNTIES FROM COMPLETELY
DECOUPLING AND STAY A BIT WARMER WHILE THE EAST WILL AGAIN DROP TO
AROUND 40 DEGREES. SOUTHEASTERLY WINDS WILL CONTINUE INTO FRIDAY
AND FRIDAY NIGHT AS A LEE TROUGH CONTINUES OVER THE WESTERN
PLAINS. MODELS ARE ALL IN FAIRLY DECENT AGREEMENT ON A WEAK
SHORTWAVE COMING OVER THE UPPER RIDGE AND SOME DECENT ISENTROPIC
LIFT PRODUCING SOME PRECIP FRIDAY AFTERNOON INTO FRIDAY NIGHT. AT
THIS POINT THE INSTABILITY SEEMS FAIRLY WEAK WITH SFC BASED CAPE
STAYING WEST OF OUR AREA AND ONLY A LITTLE BIT OF ELEVATED CAPE TO
WORK WITH. INCLUDED A CHANCE OF SHOWERS WITH ISOLATED
THUNDERSTORMS THROUGH FRIDAY NIGHT WITH BEST CHANCES IN OUR WEST.
SATURDAY-TUESDAY...00Z MODELS CONTINUE TO SUGGEST THE SYNOPTIC
PATTERN WILL BE DOMINATED BY LONGWAVE TROUGHING OVER THE WESTERN
US...WITH SOME DEGREE OF MID/UPPER LEVEL RIDGING INTO THE PLAINS
DURING MUCH OF THIS PERIOD. A SERIES OF WEAK UPPER LEVEL SHORTWAVE
TROUGHS EJECTING OUT OF THE BROADER TROUGH TO THE WEST WILL LEAD TO
BOUTS OF SHOWERS OR THUNDERSTORMS ACROSS THE REGION WITHIN THE LOW
TO MID-LEVEL WARM AIR ADVECTION ZONE ASSOCIATED WITH THE INDIVIDUAL
WAVES. WITH THIS TYPE OF PATTERN...CONFIDENCE IN THE
TIMING/PLACEMENT OF INDIVIDUAL WAVES IS LOW...SO CONTINUED TO CARRY
SOME POPS FOR MUCH OF THE PERIOD...ALTHOUGH MANY DRY HOURS ARE
EXPECTED.
THE 00Z GFS/ECMWF SUGGEST A TREND TO A MORE PREDOMINANT ACTIVE
SOUTHWEST FLOW PATTERN ACROSS THE PLAINS TOWARDS THE MIDDLE OF NEXT
WEEK...ALTHOUGH THE GFS IS MORE AMPLIFIED. THE GFS/ECMWF 925 MB
TEMPS RISE TO NEAR 20C ON TUESDAY...SUPPORTING HIGH TEMPS RISING
FROM MAINLY THE 60S OVER THE WEEKEND INTO THE 70S BY MONDAY OR
TUESDAY...WITH LOWS PRIMARILY IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 125 PM CDT WED MAY 22 2013
MVFR STRATUS DECK AND LIGHT RAIN SHOWERS HAVE MOVED JUST SOUTH OF
KBJI AND KFAR WITH CLEARING TO THE NORTH OF THIS LINE. EXPECT VFR
CONDITIONS TO PERSIST AT ALL TAF SITES THROUGH 18 UTC THURSDAY WITH
NORTHEAST WINDS GUSTING AT TIMES TO 25 KTS THIS AFTERNOON WEAKENING
AFTER SUNSET.
&&
.HYDROLOGY...
ISSUED AT 125 PM CDT WED MAY 22 2013
RIVER FLOOD WARNINGS REMAIN IN EFFECT AT WALHALLA AND NECHE ALONG
THE PEMBINA RIVER...WITH WALHALLA HAVING CRESTED EARLIER.
BIGGEST FORECAST CHANGE IS ALONG PARK RIVER AT GRAFTON WHERE THE
RECENT RAINFALL HAS TRIGGERED RAPID STAGE RISES TOWARD MAJOR AND
ULTIMATELY NEAR RECORD FLOOD LEVELS.
RIVER FLOOD WARNINGS ARE NOW IN EFFECT FOR MOST OF THE NORTHERN
MAINSTEM RED AS WELL AS THE SOUTHERN VALLEY MINNESOTA TRIBUTARIES
TO THE RED. THESE POINTS ARE ALL EXPECTED TO ACHIEVE MINOR FLOOD
STAGE EXCEPT FOR OSLO WHERE MODERATE FLOODING IS FORECAST.
AREAL FLOOD WARNINGS WILL BE IN EFFECT FOR PEMBINA...EASTERN
CAVALIER...AND WALSH COUNTIES THROUGH THURSDAY. BY THEN AREAL
FLOODING SHOULD BECOME LESS OF A CONCERN WITH LITTLE PRECIPITATION
AND THE CHANCE FOR SOME DRYING WITH WARMER TEMPERATURES.
A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY AFTERNOON FOR
AREAS DOWNSTREAM OF THE RENWICK DAM ON THE TONGUE RIVER. WATER
REMAINS VERY HIGH AT THE DAM SITE AND IS BEING HELD BACK BY A
CONSTRUCTED EARTHEN LEVEE ON TOP OF THE DAM STRUCTURE. ALSO...
OFFICIALS ARE CONTINUING TO MONITOR SEVERAL RETENTION DAMS TO THE
WEST OF RENWICK DAM.
AT THIS TIME...OFFICIALS NOTE THE TEMPORARY LEVEE ON TOP OF THE
RENWICK DAM APPEARS TO BE STABLE AND WILL BE CONTINUALLY MONITORED.
HOWEVER...THE THREAT REMAINS AND FAILURE WOULD MEAN MAJOR FLOODING
WOULD BE IMMINENT FOR THE CITIES OF AKRA...CAVALIER...AND BATHGATE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NDZ008.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...ROGERS
HYDROLOGY...BH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1233 PM CDT WED MAY 22 2013
.UPDATE...
ISSUED AT 1230 PM CDT WED MAY 22 2013
MAIN CHANGE TO THE FORECAST WAS TO INCREASE MAX TEMPERATURES THIS
AFTERNOON A COUPLE OF DEGREES IN MOST LOCATIONS. TEMPERATURES HAVE
BEEN RISING A LITTLE MORE QUICKLY THAN INITIALLY ANTICIPATED...AND
THE LATEST GFS LAMP GUIDANCE SUPPORTS THE SLIGHTLY WARMER VALUES.
THE REST OF THE FORECAST IS IN GOOD SHAPE AND ONLY CHANGES WERE TO
CAPTURE CURRENT TRENDS.
UPDATE ISSUED AT 1006 AM CDT WED MAY 22 2013
MADE ONLY MINOR ADJUSTMENTS TO THE CURRENT FORECAST. THE 22.12Z
NAM AND LATEST RAP STILL SUGGEST A SMALL CHANCE FOR A SHOWER IN
THE FAR SOUTHEAST CORNER OF THE FORECAST AREA TODAY. DID NOT
INCREASE RAIN CHANCES IN THAT AREA FOR THE UPDATE...BUT WILL HAVE
TO KEEP AN EYE ON RADAR TRENDS IN CASE A STRAY SHOWER TRIES TO
MOVE IN LATER.
CLOUDS CONTINUE TO CLEAR FROM NORTH TO SOUTH...WITH THE MOST
ABUNDANT CLOUD COVER IN THE SOUTHERN JAMES RIVER VALLEY AS OF MID
MORNING. ADJUSTED NEAR TERM SKY COVER GRIDS TO REFLECT THE
TRENDS...WITH THE FORECAST FOR THIS AFTERNOON STILL ON TRACK.
UPDATE ISSUED AT 641 AM CDT WED MAY 22 2013
SURFACE HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION THIS
MORNING. ENOUGH GRADIENT FLOW HAS DEVELOPED TO MIX OUT MORNING FOG
ACROSS THE NORTHERN PORTIONS OF THE STATE. AS OF THE 11Z
OBS...THERE WAS NO FOG REPORTED ACROSS THE NORTHERN CWA. AS A
RESULT...REMOVED MORNING FOG WORDING FROM THE GRIDS AND ZONES.
FURTHERMORE...REGIONAL RADARS ARE NOT DETECTING ANY SHOWER
ACTIVITY ACROSS THE SOUTHERN CWA. LOWERED MORNING POPS AS A
RESULT. OTHERWISE...ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS
BASED ON CURRENT OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS
HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT WED MAY 22 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE DRY AND COOL
WEATHER IN THE WAKE OF THE STORM SYSTEM WHICH BROUGHT WIDESPREAD
HEAVY RAINFALL TO MUCH OF WEST AND CENTRAL NORTH DAKOTA THE PAST
SEVERAL DAYS.
CURRENTLY...MOSTLY CLEAR CONDITIONS ACROSS NORTHERN NORTH DAKOTA
WITH HIGH PRESSURE SLOWLY BUILDING SOUTH INTO THE NORTHERN PLAINS.
SCATTERED LIGHT RAIN CONTINUES TO ADVECT WEST-SOUTHWEST FURTHER
SOUTH...STILL UNDER THE INFLUENCE OF THE CLOSED UPPER LOW WHICH IS
MOVING SLOWLY SOUTH AND EAST INTO THE MID/UPPER MISSISSIPPI VALLEY
REGION. PRECIPITATION CHANCES WILL CONTINUE TO DIMINISH FROM NORTH
TO SOUTH AS THE LOW MOVES OUT OF THE REGION...AND SKIES WILL
CONTINUE TO CLEAR FROM NORTH TO SOUTH NOW THROUGH 15Z. WILL MAINTAIN
MORNING FOG NORTH WITH T/TD SPREADS NEARING ZERO AS SKIES
CLEAR...AND SEVERAL OBSERVING SITES REPORTING FOG. WILL MONITOR FOR
POSSIBLE DENSE FOG...HOWEVER WINDS ARE EXPECTED TO INCREASE SHORTLY
AFTER SUNRISE SO DO NOT EXPECT THE DURATION OF THE FOG TO BE VERY
LONG.
THE RIDGE CONTINUES TO BUILD SLOWLY SOUTH ACROSS THE CENTRAL
DAKOTAS TODAY...WITH GENERALLY SUNNY SKIES AND HIGHS IN THE 60S. THE
LATEST 00Z GFS/ECMWF DO GENERATE 100-200 J/KG OF MUCAPE THIS
AFTERNOON/EARLY EVENING ALONG A COLD FRONT PUSHING SOUTH ACROSS
SOUTHERN MANITOBA INTO NORTHEASTERN NORTH DAKOTA. FOR NOW WILL LEAVE
THINGS DRY...BUT COULD SEE A SHOWER OR TWO AROUND THE TURTLE
MOUNTAINS/DEVILS LAKE BASIN AREA.
ANOTHER COOL NIGHT WEDNESDAY THANKS TO CLEAR SKIES...LIGHT
WINDS...AND SFC DEWPOINTS RANGING FROM 35-45. THIS SHOULD RESULT IN
LOW TEMPERATURES AROUND 40 TO 45. SOUTHEAST RETURN FLOW INCREASES
LATE TONIGHT FAR WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 343 AM CDT WED MAY 22 2013
DRY CONDITIONS ARE EXPECTED THURSDAY AS MID/UPPER LEVEL RIDGING
DEVELOPS OVER THE PLAINS. GRADIENT FLOW WILL INCREASE WEST IN
RESPONSE TO AN UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST. WIND
ADVISORY CONDITIONS WILL BE POSSIBLE OVER SOUTHWESTERN NORTH DAKOTA
THURSDAY AFTERNOON/EVENING.
THE MEDIUM RANGE MODELS PROG THE FIRST IMPULSE TO EJECT FROM OF THE
AFOREMENTIONED PACIFIC NORTHWEST LOW OVER WESTERN AND CENTRAL NORTH
DAKOTA FRIDAY. THIS WILL LEAD TO THUNDERSTORM CHANCES DEVELOPING
AREAWIDE BY FRIDAY AFTERNOON.
AN UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH THE END OF THE
PERIOD. PERSISTENT SOUTHWESTERLY FLOW ALOFT COMBINED WITH GULF OF
MEXICO MOISTURE TAP WILL LEAD TO CHANCES FOR THUNDERSTORMS EACH DAY
THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. THE PERSISTENT
RETURN FLOW SHOULD ALSO ALLOW FOR A GRADUAL WARMING TREND TO DEVELOP
SATURDAY AND CONTINUE THROUGH THE END OF THE PERIOD. BY
TUESDAY...HIGHS SHOULD GENERALLY BE IN THE MID 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1230 PM CDT WED MAY 22 2013
EAST / NORTHEAST WINDS INCREASED LATE THIS MORNING...AND EXPECT
GUSTS TO NEAR 25 KTS AT ALL TERMINAL LOCATIONS THROUGH THE
AFTERNOON. WINDS WILL DIMINISH THIS EVENING...BUT WILL INCREASE
AGAIN THURSDAY MORNING. VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD...WITH ONLY PASSING SCATTERED CLOUDS AROUND 4KFT EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...NH
LONG TERM...TM
AVIATION...CK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
506 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA
AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS
SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION
ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO
TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE
MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
AFEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT FOR 21Z UPDATE...THINK CONDITIONS WILL REMAIN VFR INTO THE
EARLY EVENING...WITH BKN CLOUD BASES AROUND THE 035 TO 045 RANGE.
THE LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING
MORE ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A
BROKEN BAND OF STORMS WILL MOVE THROUGH. REMOVED PREVIOUS PROB30 AND
WENT WITH A 4HR TEMPO GROUP FOR TSRA WITH MVFR VISB. THE FRONT
SHOULD STAY WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL
SERVE AS A TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING
THURSDAY...THUS ANOTHER PROB30 GROUP TOWARD THE END OF THE PERIOD.
AS A RESULT...WIND DIRECTION SHOULD REMAIN S TO SW.
ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD
REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD
DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE
NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY
MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF
SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 87% HIGH 88% MED 79%
KGSP HIGH 92% MED 71% HIGH 91% HIGH 100%
KAVL MED 77% HIGH 81% HIGH 86% HIGH 100%
KHKY HIGH 80% LOW 56% MED 72% HIGH 83%
KGMU HIGH 92% MED 69% HIGH 88% HIGH 100%
KAND HIGH 93% MED 74% HIGH 88% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/PM/WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
245 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
AFEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...THINK CONDITIONS WILL REMAIN VFR INTO THE EARLY
EVENING...WITH SCT CLOUD BASES AROUND THE 035 TO 045 RANGE. THE
LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING MORE
ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A BROKEN
BAND OF STORMS WILL MOVE THROUGH. WILL CARRY A PROB30 FOR THIS IN
THE 03Z TO 06Z TIME FRAME. EXPECT ADJUSTMENTS TO THE PROB AND MIGHT
HAVE TO INCLUDE A TEMPO LATER IN THE DAY. WITH COOLING...THE CLOUD
BASES SHOULD FALL INTO MVFR RANGE LATE THIS EVENING AND STAY THERE
THROUGH EARLY AFTERNOON ON THURSDAY. FOG COULD BECOME A PROBLEM
AROUND DAYBREAK IF SIGNIFICANT RAIN HAPPENS LATE TONIGHT.
OTHERWISE...THE VSBY WAS KEPT ABOVE 5 MILES. THE FRONT SHOULD STAY
WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL SERVE AS A
TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING THURSDAY...THUS ANOTHER
PROB30 GROUP TOWARD THE END OF THE PERIOD. AS A RESULT...WIND
DIRECTION SHOULD REMAIN S TO SW.
ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD
REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD
DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE
NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY
MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF
SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 86% HIGH 100% HIGH 86% HIGH 90%
KGSP HIGH 100% MED 79% HIGH 87% HIGH 97%
KAVL HIGH 93% MED 77% HIGH 81% HIGH 97%
KHKY HIGH 93% MED 73% LOW 54% HIGH 80%
KGMU HIGH 100% MED 79% HIGH 83% HIGH 94%
KAND HIGH 100% HIGH 80% HIGH 82% HIGH 95%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...PM
SHORT TERM...TS
LONG TERM...SBK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
205 PM CDT WED MAY 22 2013
.MESOSCALE UPDATE...FOR THIS AFTERNOON AND EVENING...
VIS SATELLITE IMAGERY CONTINUES TO SHOW A BROKEN CLOUD DECK OVER
MIDDLE TN THAT HAS BEEN LIMITING DIURNAL HEATING UNTIL THE LAST
HOUR OR SO. WITH THE CLOUD DECK DETERIORATING ENOUGH TO ALLOW
SUNLIGHT TO POKE THROUGH...INSTABILITY AND LOW LEVEL
THERMODYNAMICS ARE INCREASING. SPC MESOANALYSIS SHOWS A 3 HOUR
CAPE CHANGE ACROSS MUCH OF THE MID STATE OF ABOUT 400-600 J/KG
WITH A CORRESPONDING DECREASE IN CONVECTIVE INHIBITION. FORECAST
CAPE VALUES APPEAR TO BE BEST OUT EAST ON THE CUMBERLAND BUT
GREATER THAN 1500 J/KG ACROSS THE MID STATE. FORECAST SOUNDINGS ARE
UNCAPPED WITH STRONG LOW LEVEL LAPSE RATES AS WELL. RUC FORECAST
SOUNDINGS SHOW CONVECTIVE TEMPERATURES BEING REACHED BETWEEN NOW
AND THE NEXT HOUR SO EXPECT INITIATION OF CONVECTION TO BEGIN VERY
SOON.
DYNAMICALLY SPEAKING...UPPER LEVEL FORCING IS INCREASING
ASSOCIATED WITH HEIGHT FALLS OVER WESTERN TENNESSEE. THE BEST
UPPER LEVEL SUPPORT IS COINCIDENT WITH THE RRQ OF THE NEGATIVELY
TILTED 300 MB LOW. AS THIS SHORTWAVE CONTINUES TO SWING AROUND
AND AMPLIFY THE UPPER LEVEL LIFT IN ASSOCIATION WITH THE
LOW...THE POSSIBILITY FOR SEVERE HAIL AND WINDS WILL INCREASE.
EXPECT ISOLATED TO SCATTERED STRONG TO POSSIBLY SEVERE STORMS
BEGIN OUT EAST WHERE BETTER THERMODYNAMIC INSTABILITY IS BEST. IN
THE NEXT FEW HOURS AS LOCATIONS OUT WEST CONTINUE TO
DESTABILIZE...THE FOCUS FOR SEVERE POTENTIAL WILL TRANSITION TO
THE FRONT WHERE UPPER LEVEL SUPPORT AND SHEAR IS BEST. BELIEVE LARGE
HAIL AND DAMAGING STRAIGHT LINE WINDS ARE THE BIGGEST THREATS.
&&
.PREV DISCUSSION... /ISSUED 1137 AM CDT WED MAY 22 2013/
AVIATION 18Z DISCUSSION...
WELL STACKED TROUGH TO PASS EASTWARD THROUGH THE MID STATE TODAY.
CONVECTION EXPECTED TO DEVELOP WITH THE BEST COVERAGE ACROSS
EASTERN MIDDLE TN. A FEW STORMS COULD REACH STRONG TO SEVERE
LIMITS. AFT 00Z...CONVECTION WILL DIMINISH BUT CLOUDINESS AND SOME
LATE NIGHT FOG WILL PERSIST. REDUCED VSBYS AND CIGS AOB 1KFT WILL
OCCUR AT CSV AFT 06Z. IMPROVING CONDITIONS AREA WIDE AFT 12Z.
PREV DISCUSSION... /ISSUED 1037 AM CDT WED MAY 22 2013/
UPDATE...
HAVE UPDATED THE FORECAST TO PROVIDE A LITTLE BETTER TIMING OF THE
EXPECTED CONVECTION THIS AFTN. REST OF THE FCST APPEARS IN GOOD
SHAPE.
MORNING UA ANALYSIS DEPICTS A SEASONALLY STRONG SOMEWHAT
NEGATIVELY TILTED MID LVL SHORT WAVE ACRS ARKANSAS APPROACHING THE
AREA. THE REGION IS ALSO ENTERING THE RR QUAD OF A RELATIVELY
STRONG UPPER LVL JET STREAK WHICH WILL ENHANCE LIFT THIS
AFTERNOON. THERMODYNAMICS DON`T LOOK ALL THAT IMPRESSIVE RIGHT NOW
AS THE ATMOS IS PRETTY WORKED OVER AND A FAIR AMOUNT OF DEBRIS
CLOUD HAS HUNG ARND. MORNING SOUNDING DEPICTS A DEEP DRY/CAPPED
LOWER ATMOSPHERE THAT IS INHIBITING ANY DEVELOPMENT. DO EXPECT A
LITTLE MORE SUN TO DEVELOP...AND A SLOW INCRS IN LLVL MSTR IS
STILL ANTICIPATED. THE COMBINATION OF COOLING MID LVL TEMPS AND A
WARMING/MOISTENING LOWER ATMOS WILL ALLOW CONVECTION TO INITIATE
MOST LIKELY RIGHT ALONG A COLD FRONT PROGGED TO CROSS THE AREA IN
THE MID/LATE AFTN. DECENT SPEED SHEAR IN PLACE SO EXPECT ACTIVITY
TO ORIENT IN A LINE WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE.
SPC CONTINUES A VERY LOW CHANCE OF A TORNADO AS WELL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1137 AM CDT WED MAY 22 2013
.AVIATION 18Z DISCUSSION...
WELL STACKED TROUGH TO PASS EASTWARD THROUGH THE MID STATE TODAY.
CONVECTION EXPECTED TO DEVELOP WITH THE BEST COVERAGE ACROSS
EASTERN MIDDLE TN. A FEW STORMS COULD REACH STRONG TO SEVERE
LIMITS. AFT 00Z...CONVECTION WILL DIMINISH BUT CLOUDINESS AND SOME
LATE NIGHT FOG WILL PERSIST. REDUCED VSBYS AND CIGS AOB 1KFT WILL
OCCUR AT CSV AFT 06Z. IMPROVING CONDITIONS AREA WIDE AFT 12Z.
&&
.PREV DISCUSSION... /ISSUED 1037 AM CDT WED MAY 22 2013/
UPDATE...
HAVE UPDATED THE FORECAST TO PROVIDE A LITTLE BETTER TIMING OF THE
EXPECTED CONVECTION THIS AFTN. REST OF THE FCST APPEARS IN GOOD
SHAPE.
MORNING UA ANALYSIS DEPICTS A SEASONALLY STRONG SOMEWHAT
NEGATIVELY TILTED MID LVL SHORT WAVE ACRS ARKANSAS APPROACHING THE
AREA. THE REGION IS ALSO ENTERING THE RR QUAD OF A RELATIVELY
STRONG UPPER LVL JET STREAK WHICH WILL ENHANCE LIFT THIS
AFTERNOON. THERMODYNAMICS DON`T LOOK ALL THAT IMPRESSIVE RIGHT NOW
AS THE ATMOS IS PRETTY WORKED OVER AND A FAIR AMOUNT OF DEBRIS
CLOUD HAS HUNG ARND. MORNING SOUNDING DEPICTS A DEEP DRY/CAPPED
LOWER ATMOSPHERE THAT IS INHIBITING ANY DEVELOPMENT. DO EXPECT A
LITTLE MORE SUN TO DEVELOP...AND A SLOW INCRS IN LLVL MSTR IS
STILL ANTICIPATED. THE COMBINATION OF COOLING MID LVL TEMPS AND A
WARMING/MOISTENING LOWER ATMOS WILL ALLOW CONVECTION TO INITIATE
MOST LIKELY RIGHT ALONG A COLD FRONT PROGGED TO CROSS THE AREA IN
THE MID/LATE AFTN. DECENT SPEED SHEAR IN PLACE SO EXPECT ACTIVITY
TO ORIENT IN A LINE WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE.
SPC CONTINUES A VERY LOW CHANCE OF A TORNADO AS WELL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
148 PM EDT WED MAY 22 2013
.SYNOPSIS...
A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO
THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT
THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH
PRESSURE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 PM EDT WEDNESDAY...
ADJUSTED POPS ACROSS TO LATEST RADAR TRENDS WITH CONVECTION
DEVELOPING OVER THE MOUNTAINS.
AS OF 925 AM EDT WEDNESDAY...
ADJUSTED POPS FOR LATEST RADAR TREND...SHAPING POPS THIS MORNING
INTO TOWARDS LATEST RNK WRFARW. KEPT THE BEST CHANCE FOR
THUNDERSTORMS THIS AFTERNOON IN THE WEST. SWODY1 HAS PLACED A
SLIGHT RISK JUST TO OUR WEST. MORNING RUN SHOWED THE POTENTIAL
FOR LINE OF CONVECTION REACHING THE WEST BETWEEN 00Z AND 06Z
TONIGHT. WILL REVIEW 12Z RUN BEFORE MAKING ANY MAJOR ADJUSTMENTS
FOR TONIGHT. MODIFIED TEMPERATURES AND DEW POINTS THIS MORNING
INTO THIS AFTERNOON. RAISED HIGH TEMPERATURES UP A FEW DEGREES IN
SOUTHEAST. UPDATED FIRE WEATHER GRIDS...FWFRNK OUT. ADDITIONAL
CHANGES LATER TODAY.
AS OF 340 AM EDT WEDNESDAY...
A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL
FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST
FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE
RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING
WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA.
HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION
THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE
ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE
CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE
AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS
AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING
NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL
CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON.
EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT
THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE
PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS
INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE
INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN
00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS
CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY
IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH
FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY
THIS EVENING TO COVER THIS POTENTIAL.
THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF
OUR REGION TODAY INTO TONIGHT.
CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT
AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS
TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID
80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID
60S SE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 AM EDT WEDNESDAY...
A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION
BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE
CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY.
OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT
THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE.
LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY
ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION
COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM
PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE
PIEDMONT AND TIDEWATER AREAS OF VA/NC.
THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH
LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE
MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR
ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO
THE LOWER TO MID 70S EAST.
FRIDAY NIGHT AND SATURDAY:
QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM
FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST
OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE
BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD
GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY
FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE
EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY
THE END OF THE PERIOD.
WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO
WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT
LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE
PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN
EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING.
THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY
NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE
ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY
FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC
SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE
LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING
SOAKED AGAIN MONDAY-WEDNESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 140 PM EDT WEDNESDAY...
SCATTERED MVFR/IFR CONVECTION DEVELOPING IN THE WARM UNSTABLE AIR
ACROSS CWA THIS AFTERNOON. THE BEST CHANCE OF THUNDERSTORMS WILL
OCCUR ACROSS WESTERN TAF SITES OF BLF/LWB/RNK. RNKWRF ARW SHOWED
GOOD COVERAGE OF STORM ACROSS THE MOUNTAINS THIS AFTERNOON INTO
TONIGHT. ECMWF/GFS GENERALLY CONSISTENT ON A LINE OF STRONG
THUNDERSTORMS MOVING INTO FAR SW VA FROM KY/TN IN THE 00Z-04Z TIME
FRAME...THEN GENERALLY DISSIPATING AS MOVE EAST. FOR THE EAST...
THERE IS POTENTIAL TSRA DEVELOPMENT ACROSS THE NC
PIEDMONT...LIFTING NORTHWARD TOWARD LYH/DAN/EVEN ROA BY LATE
AFTERNOON INTO THIS EVENING.
S-SW WINDS 5-10KTS THROUGH TAF VALID PERIOD...WITH LOW END GUSTS
ACROSS THE PIEDMONT. AREAS OF FOG WILL DEVELOP TONIGHT INTO
WEDNESDAY MORNING WHERE RAIN FALLS THIS AFTERNOON INTO THIS
EVENING.
MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/JH/KK
SHORT TERM...WP
LONG TERM...WP
AVIATION...KK/RAB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1252 PM CDT WED MAY 22 2013
.SHORT TERM...(TODAY AND FRIDAY)
ISSUED AT 309 AM CDT WED MAY 22 2013
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH TONIGHT...
THEN POSSIBLE PATCHY FROST OVER CENTRAL WISCONSIN THURSDAY NIGHT.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL LOW OVER
THE NORTHERN PLAINS AND SHORTWAVE TROUGHS ROTATING AROUND THE UPPER
LEVEL LOW. LATEST MOSAIC RADAR INDICATING SCATTERED SHOWERS
EXTENDING FROM LAKE SUPERIOR INTO SOUTHWEST MINNESOTA AND ANOTHER
AREA OF SHOWERS AND THUNDERSTORMS FROM WESTERN ILLINOIS INTO
SOUTHERN LAKE MICHIGAN.
THE 22.00Z GFS/NAM ARE IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL
FLOW THROUGH FORECAST PERIOD. BOTH MODELS ARE IN DECENT AGREEMENT
LIFTING SHORTWAVE TROUGH OVER MISSOURI AND EASTERN KANSAS
INTO SOUTHERN WISCONSIN TODAY. THE 22.00Z GFS/NAM AND 22.03Z RAP ARE
IN AGREEMENT IN INCREASING PV ADVECTION...QG FORCING AND VERTICAL
MOTION OVER THE FORECAST AREA 12-18Z TODAY AND DEVELOP
PRECIPITATION OVER MUCH OF THE FORECAST AREA BY 18Z TODAY.
CONFIDENCE IS INCREASING THE FORECAST AREA WILL SEE PRECIPITATION
DEVELOP OVER FORECAST AREA BY 18Z. THE DETERMINISTIC MODELS INDICATE
0-6KM MOST UNSTABLE CAPE 300-500 J/KG OVER SOUTHEASTERN HALF OF THE
FORECAST AREA AFTER 15Z TODAY. WILL CONTINUE TO MENTION ISOLATED
THUNDERSTORMS.
THE 22.00Z GFS/NAM SUGGEST UPPER LEVEL LOW WEAKENS AND DRIFTS SLOWLY
EAST INTO THE GREAT LAKES REGION...AS AN UPPER LEVEL TROUGH
DIGS OVER EASTERN GREAT LAKES REGION TONIGHT. WITH SURFACE RIDGE
BUILDING INTO SOUTHERN ONTARIO AND THE WESTERN GREAT LAKES REGION...
CLOUDS AND PRECIPITATION WILL DIMINISH FROM NORTH TO SOUTH ACROSS
FORECAST AREA AFTER 06Z THURSDAY.
DRY NORTHEASTERLY FLOW ALOFT DEVELOPS OVER FORECAST AREA THURSDAY.
THE 22.00Z GFS/NAM BUFKIT SOUNDINGS ARE INDICATING FORECAST AREA
MIXING UP TO 825MB BY 21Z. THIS SHOULD ALLOW FOR DEWPOINTS TO FALL
INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS MUCH OF THE FORECAST AREA
THURSDAY AFTERNOON.
NEXT CONCERN IS LOW TEMPERATURES AND PATCHY FROST FRIDAY MORNING...
WITH THE COMBINATION OF SURFACE RIDGE CENTERED AND DRY AIRMASS OVER
FORECAST AREA...TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE
30S ACROSS PORTIONS OF CENTRAL WISCONSIN. PATCHY FROST WILL BE
POSSIBLE ACROSS THIS PART OF THE FORECAST AREA.
.LONG TERM...(FRIDAY NIGHT INTO TUESDAY)
ISSUED AT 309 AM CDT WED MAY 22 2013
MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH FORECAST
PERIOD. THE 22.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON TIMING OF
SHORTWAVE TROUGHS OVER-TOPPING UPPER LEVEL RIDGE OVER THE CENTRAL
UNITED STATES AND PLACEMENT OF THE SURFACE RIDGE OVER THE
GREAT LAKES REGION. WITH THIS...CONFIDENCE IN FORECAST IS LOW AND
WILL CONTINUE WITH CONSISTENCY OF PRECIPITATION CHANCES THROUGH
FORECAST PERIOD. TEMPERATURES WILL CLIMB INTO THE 60S FOR THE
MEMORIAL DAY WEEKEND AND BE IN THE 70S TUESDAY...AS THE
DETERMINISTIC MODELS INDICATE WARMER AIR ALOFT TO FILTER INTO THE
REGION BY 00Z TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1252 PM CDT WED MAY 22 2013
CLOSED LOW LOCATED OVER NORTHEAST IA WILL SLOWLY FILL IN AND
MOVE EAST INTO LOWER MI BY MORNING. PLAN ON IFR/MVFR CLOUD
COVER AND BAND OF SHRA NORTH OF THE LOW TO PERSIST INTO TONIGHT.
THEN LOOK FOR FAIRLY RAPID IMPROVEMENT INTO VFR CATEGORY AROUND
07Z AT KRST AND AROUND 09Z AT KLSE AS DRIER AIR WORKS IN FROM THE
NORTH. HIGH PRESSURE WILL PROVIDE CLEAR SKIES ON THURSDAY WITH
NORTH/NORTHEAST WINDS IN THE 10-20KT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....DTJ
LONG TERM......DTJ
AVIATION...DAS