Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/02/13
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
935 PM CDT WED MAY 1 2013
.DISCUSSION...
OVERALL FORECAST ON TRACK. A CHANCE OF LIGHT CONVECTION WILL
CONTINUE OVERNIGHT AS THE UPPER LOW OVER THE LOWER MS VALLEY ROTATES
SOME UPPER ENERGY INTO AR. IT WILL SLOWLY DRIFT ESE LATE TONIGHT AND
THURSDAY AS THE UPPER TROUGH PUSHES IT EAST. TEMPS WILL REMAIN MILD
TONIGHT. THE COLD FRONT WILL MAKE SLOW PROGRESS TOWARD AR TONIGHT AS
THE UPPER PATTERN HOLDS PARALLEL OUT WEST. BETTER MOVEMENT WILL
HAPPEN THURSDAY TO FRIDAY AS THE UPPER TROUGH SWINGS THROUGH THE
PLAINS...AND WELL BELOW NORMAL TEMPS...AND A SLIGHT CHANCE OF WINTER
PRECIP MATERIALIZE OVER NW TO N AR FRIDAY AM AND SATURDAY AM. (59)
&&
.PREV DISCUSSION... /ISSUED 651 PM CDT WED MAY 1 2013/
.AVIATION...
UPPER LOW OVER NE LOUISIANA CONTINUES TO ROTATE SHOWERS INTO FAR
SOUTHERN AND EASTERN ARKANSAS. HOWEVER RECENT RADAR TRENDS HAVE
SHOWN A LULL IN CONVECTIVE ACTIVITY. RAPID UPDATE MODEL RUNS SHOW
THIS TREND CONTINUING BEFORE SOME MORE SHOWERS MOVE INTO THE AREA
AFTER 03Z. HAVE TRIED TO MIMIC THIS TIMING SINCE THE RUC MODEL IS
HANDLING CURRENT RADAR TRENDS NICELY...AND HAVE TEMPO -SHRA WITH
MVFR CIGS FOR ALL CENTRAL SOUTHERN SITES BETWEEN 03Z AND 09Z. MORE
WIDESPREAD SHOWER ACTIVITY FOR CENTRAL/SOUTHERN SITES SHOULD BE
SEEN AFTER 16Z OR SO THURSDAY MORNING. FOR KHRO AND KBPK...SHOWER
ACTIVITY WILL LIKELY HOLD OFF UNTIL A COLD FRONT APPROACHES FROM
THE NORTH AND INTERACTS WITH LIFT ON THE NORTH SIDE OF THE LA
UPPER LOW. HAVE VCSH BEGINNING AT 12Z...THEN PREVAILING -RA AFTER
18Z FOR BOTH OF THESE SITES. WITH REGARD TO CIGS AND VSBY...CIGS
WILL GRADUALLY LOWER TO LOW-END MVFR OR IFR LEVELS. VSBY SHOULD
STAY ABOVE 5SM EXCEPT IN -SHRA/-RA CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 338 PM CDT WED MAY 1 2013/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
A STORM SYSTEM ALOFT OVER LOUISIANA WAS SPREADING SHOWERS AND A
FEW THUNDERSTORMS INTO MAINLY CENTRAL AND SOUTHERN ARKANSAS THIS
AFTERNOON. PRECIPITATION WAS MORE ISOLATED TOWARD THE MISSOURI
BORDER. MEANWHILE...A COLD FRONT WAS APPROACHING FROM THE PLAINS.
ON THURSDAY...MOISTURE FROM THE GULF COAST SYSTEM WILL BE
IN PLACE WHEN THE COLD FRONT ARRIVES. AS THE FRONT PUSHES INTO
THE REGION...SHOWERS WILL BECOME LIKELY WITH A CHANCE OF
THUNDERSTORMS. AT THIS TIME...INSTABILITY WILL BE MARGINAL...
AND ANY SEVERE WEATHER REMAINING ISOLATED.
SHOWERS WILL REMAIN LIKELY THURSDAY NIGHT AS MUCH COOLER
AIR BEGINS SPREADING INTO ARKANSAS BEHIND THE FRONT. MODELS PRETTY
MUCH AGREE IT WILL BE COLD ENOUGH FOR A PERIOD OF LIGHT
SNOW/FLURRIES IN THE NORTHWEST COUNTIES BY FRIDAY MORNING. WHILE
MOISTURE WILL BE ON THE DECLINE...ADDED SOME FLAKES TO THE
FORECAST FOR A FEW HOURS.
IF THIS SNOW COMES TO FRUITION...IT WILL BE THE FIRST FLAKES
EVER IN ARKANSAS IN MAY ACCORDING TO OFFICIAL RECORDS.
AS THE PERIOD ENDS...LOW PRESSURE WILL CUTOFF FROM THE
MAIN FLOW ALOFT IN THE MIDDLE PART OF THE COUNTRY. THE
LOCATION/TRACK OF THE LOW IS IN QUESTION...BUT SOUTHERN MISSOURI
SEEMS THE MOST LIKELY SPOT FRIDAY NIGHT AND SATURDAY. THE LOW
WILL KEEP CLOUDS AND CHANCES FOR SHOWERS IN THE FORECAST WITH MUCH
BELOW NORMAL AFTERNOON TEMPERATURES MAINLY IN THE 50S/60S. NORMAL
HIGHS ARE IN THE 70S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
DEPENDING ON TRACK OF UPPER LOW...THERE MAY BE SOME PRECIPITATION
LEFT ACROSS THE REGION. FOR NOW...HAVE LEANED TOWARDS THE
EUROPEAN...WITH DRY CONDITIONS SUNDAY NIGHT INTO TUESDAY...BEFORE
THE NEXT SYSTEM ARRIVES WEDNESDAY. TEMPERATURES WILL REBOUND FROM
THE COOL WEEKEND...WITH HIGHS IN THE 70S BY MID WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 77 61 71 44 / 20 30 70 70
CAMDEN AR 74 64 73 45 / 60 50 70 70
HARRISON AR 79 56 61 36 / 30 20 70 70
HOT SPRINGS AR 74 63 70 43 / 60 40 70 70
LITTLE ROCK AR 75 63 73 45 / 50 40 70 70
MONTICELLO AR 74 64 75 46 / 60 60 70 70
MOUNT IDA AR 76 61 65 40 / 60 30 70 70
MOUNTAIN HOME AR 79 59 64 40 / 30 20 70 70
NEWPORT AR 78 62 74 46 / 20 30 70 70
PINE BLUFF AR 72 63 73 45 / 60 50 70 70
RUSSELLVILLE AR 78 61 68 41 / 30 30 70 70
SEARCY AR 75 62 71 45 / 20 40 70 70
STUTTGART AR 73 63 73 46 / 40 40 70 70
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...64
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
651 PM CDT WED MAY 1 2013
.DISCUSSION...
UPDATED FOR THE 00Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
UPPER LOW OVER NE LOUISIANA CONTINUES TO ROTATE SHOWERS INTO FAR
SOUTHERN AND EASTERN ARKANSAS. HOWEVER RECENT RADAR TRENDS HAVE
SHOWN A LULL IN CONVECTIVE ACTIVITY. RAPID UPDATE MODEL RUNS SHOW
THIS TREND CONTINUING BEFORE SOME MORE SHOWERS MOVE INTO THE AREA
AFTER 03Z. HAVE TRIED TO MIMIC THIS TIMING SINCE THE RUC MODEL IS
HANDLING CURRENT RADAR TRENDS NICELY...AND HAVE TEMPO -SHRA WITH
MVFR CIGS FOR ALL CENTRAL SOUTHERN SITES BETWEEN 03Z AND 09Z. MORE
WIDESPREAD SHOWER ACTIVITY FOR CENTRAL/SOUTHERN SITES SHOULD BE
SEEN AFTER 16Z OR SO THURSDAY MORNING. FOR KHRO AND KBPK...SHOWER
ACTIVITY WILL LIKELY HOLD OFF UNTIL A COLD FRONT APPROACHES FROM
THE NORTH AND INTERACTS WITH LIFT ON THE NORTH SIDE OF THE LA
UPPER LOW. HAVE VCSH BEGINNING AT 12Z...THEN PREVAILING -RA AFTER
18Z FOR BOTH OF THESE SITES. WITH REGARD TO CIGS AND VSBY...CIGS
WILL GRADUALLY LOWER TO LOW-END MVFR OR IFR LEVELS. VSBY SHOULD
STAY ABOVE 5SM EXCEPT IN -SHRA/-RA CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 338 PM CDT WED MAY 1 2013/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
A STORM SYSTEM ALOFT OVER LOUISIANA WAS SPREADING SHOWERS AND A
FEW THUNDERSTORMS INTO MAINLY CENTRAL AND SOUTHERN ARKANSAS THIS
AFTERNOON. PRECIPITATION WAS MORE ISOLATED TOWARD THE MISSOURI
BORDER. MEANWHILE...A COLD FRONT WAS APPROACHING FROM THE PLAINS.
ON THURSDAY...MOISTURE FROM THE GULF COAST SYSTEM WILL BE
IN PLACE WHEN THE COLD FRONT ARRIVES. AS THE FRONT PUSHES INTO
THE REGION...SHOWERS WILL BECOME LIKELY WITH A CHANCE OF
THUNDERSTORMS. AT THIS TIME...INSTABILITY WILL BE MARGINAL...
AND ANY SEVERE WEATHER REMAINING ISOLATED.
SHOWERS WILL REMAIN LIKELY THURSDAY NIGHT AS MUCH COOLER
AIR BEGINS SPREADING INTO ARKANSAS BEHIND THE FRONT. MODELS PRETTY
MUCH AGREE IT WILL BE COLD ENOUGH FOR A PERIOD OF LIGHT
SNOW/FLURRIES IN THE NORTHWEST COUNTIES BY FRIDAY MORNING. WHILE
MOISTURE WILL BE ON THE DECLINE...ADDED SOME FLAKES TO THE
FORECAST FOR A FEW HOURS.
IF THIS SNOW COMES TO FRUITION...IT WILL BE THE FIRST FLAKES
EVER IN ARKANSAS IN MAY ACCORDING TO OFFICIAL RECORDS.
AS THE PERIOD ENDS...LOW PRESSURE WILL CUTOFF FROM THE
MAIN FLOW ALOFT IN THE MIDDLE PART OF THE COUNTRY. THE
LOCATION/TRACK OF THE LOW IS IN QUESTION...BUT SOUTHERN MISSOURI
SEEMS THE MOST LIKELY SPOT FRIDAY NIGHT AND SATURDAY. THE LOW
WILL KEEP CLOUDS AND CHANCES FOR SHOWERS IN THE FORECAST WITH MUCH
BELOW NORMAL AFTERNOON TEMPERATURES MAINLY IN THE 50S/60S. NORMAL
HIGHS ARE IN THE 70S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
DEPENDING ON TRACK OF UPPER LOW...THERE MAY BE SOME PRECIPITATION
LEFT ACROSS THE REGION. FOR NOW...HAVE LEANED TOWARDS THE
EUROPEAN...WITH DRY CONDITIONS SUNDAY NIGHT INTO TUESDAY...BEFORE
THE NEXT SYSTEM ARRIVES WEDNESDAY. TEMPERATURES WILL REBOUND FROM
THE COOL WEEKEND...WITH HIGHS IN THE 70S BY MID WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 77 61 71 44 / 20 30 70 70
CAMDEN AR 74 64 73 45 / 60 50 70 70
HARRISON AR 79 56 61 36 / 30 20 70 70
HOT SPRINGS AR 74 63 70 43 / 60 40 70 70
LITTLE ROCK AR 75 63 73 45 / 50 40 70 70
MONTICELLO AR 74 64 75 46 / 60 60 70 70
MOUNT IDA AR 76 61 65 40 / 60 30 70 70
MOUNTAIN HOME AR 79 59 64 40 / 30 20 70 70
NEWPORT AR 78 62 74 46 / 20 30 70 70
PINE BLUFF AR 72 63 73 45 / 60 50 70 70
RUSSELLVILLE AR 78 61 68 41 / 30 30 70 70
SEARCY AR 75 62 71 45 / 20 40 70 70
STUTTGART AR 73 63 73 46 / 40 40 70 70
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...64
AREA FORECAST DISCUSSION
NWS MIAMI FL
827 PM EDT WED MAY 1 2013
.UPDATE...
CHANCES FOR SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL PREVAIL
THROUGH THE NIGHT AS WEAKNESSES IN THE MID LEVEL FLOW CONTINUE TO
PUSH ACROSS THE AREA. LATEST IR SATELLITE IMAGERY SHOWS AN MCS
SITUATED ACROSS THE SOUTH CENTRAL GULF OF MEXICO MOVING SOUTH
TOWARD THE YUCATAN CHANNEL. LATEST SHORT TERM MODELS INCLUDING
LOCAL MODEL DATA DEPICTS A FEW ASSOCIATED SHOWERS AND
THUNDERSTORMS PUSHING EAST AND INTO THE EASTERN GULF WATERS BY
EARLY TOMORROW MORNING. KEPT CHANCE POP ACROSS THE ENTIRE AREA
THROUGH THE MORNING HOURS. UPDATE WILL BE SENT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 744 PM EDT WED MAY 1 2013/
AVIATION...
A TROUGH OF LOW PRESSURE THAT BROUGHT SHOWERS AND THUNDERSTORMS
TODAY, WILL CONTINUE TO BRING SOME SHOWER ACTIVITY INTO THE LATE
EVENING HOURS. THIS MEAN VFR TO MVFR CONDITIONS ARE EXPECTED
OVERNIGHT, WITH VFR IN THE MORNING, RETURNING TO A MIX OF VFR AND
MVFR TOMORROW. THIS IS DUE TO ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS EXPECTED TO DEVELOP AROUND MID DAY. WINDS WILL BE
LIGHT AND VARIABLE FOR A WHILE THIS EVENING, BEFORE BECOMING
EASTERLY BETWEEN 5 AND 10 KTS. THEY WILL INCREASE TO 10 TO 15 KTS
TOMORROW MORNING.
PREV DISCUSSION... /ISSUED 238 PM EDT WED MAY 1 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
LARGE CUT-OFF MID LEVEL LOW CONTINUES TO SLOWLY DRIFT EAST ACROSS
THE SOUTH CENTRAL GULF STATES. A LARGE CLUSTER OF CONVECTION
DEVELOPED ON THE SOUTHERN FRINGES OF THIS LOW AND HAS MOVED EAST
THROUGH EARLY THIS AFTERNOON AND AS OF 1830Z WAS MOVING ACROSS THE
INTERIOR AND TOWARDS THE EAST COAST METRO AREA. ANOTHER CLUSTER OF
CONVECTION IS ALSO CURRENTLY DEVELOPING OVER THE CENTRAL GULF WITH
THE HRRR SHOWING THIS MOVING ACROSS SOUTH FLORIDA THIS EVENING SO
HAVE INCREASED THE POPS FOR THE OVERNIGHT HOURS. AT THE SAME TIME, A
DEEPENING TROUGH INTO THE CENTRAL PLAINS STATES ON THURSDAY WILL
CONTINUE TO DEEPEN AND CUT OFF OVER THE MISSISSIPPI VALLEY WITH
THE SOUTHERN CUT-OFF LOW BECOMING PHASED IN WITH THIS LOW. THIS
KEEPS SOUTH FLORIDA IN RICH TROPICAL FLOW OF AIR THROUGH THE END
OF THE WEEK WITH HIGH CHANCES FOR SHOWERS AND THUNDERSTORMS.
FORECAST SOUNDINGS THROUGH THIS PERIOD LOOK QUITE SIMILAR WITH
PWAT REMAINING WELL ABOVE NORMAL FOR EARLY MAY AND A WEAK WESTERLY
STEERING FLOW. GLOBAL MODELS ARE NOW MORE IN AGREEMENT WITH THE
OVERALL SOLUTION DURING THE NEXT 48 HOURS AND SHOW THE LOW
DRIFTING TO THE SOUTHEAST BEFORE GETTING PHASED IN WITH THE
UPSTREAM DEEPENING TROUGH. THIS ON THURSDAY AND POSSIBLY FRIDAY
WILL DESTABILIZE THE ATMOSPHERE WITH COOLING 500 MB TEMPERATURES.
THE 12Z MFL SOUNDING SHOWED A TEMPERATURE OF -10 CELSIUS AND THE
GFS SHOWS COOLING TO AROUND -12 ON THURSDAY INTO FRIDAY. SO THE
CONTINUED THREAT FOR STRONG STORMS WILL ALSO BE A FACTOR. OF
COURSE THERE WILL ALWAYS BE SOME DAY TO DAY FLUCTUATIONS WITH WEAK
DISTURBANCES MOVING THROUGH THE BASE OF THE TROUGH.
LONG TERM (SATURDAY THROUGH WEDNESDAY)...
THE EXTENDED PORTION OF THE FORECAST CONTINUES TO BE HIGHLY
UNCERTAIN WITH THE GFS AND ECMWF HAVING TWO DIFFERENT SOLUTIONS TO
THE DEEPENING TROUGH. BOTH CUT THIS LOW OFF FROM THE NORTHERN
LATITUDE FLOW AS MENTIONED ABOVE. THE GFS THEN DEVELOPS A MASSIVE
CUT-OFF LOW AND THEN SLOWLY DRIFTS IT TO THE EAST THROUGH THE MIDDLE
OF NEXT WEEK. THIS WOULD TEND TO DRAW A DRIER AIR MASS ACROSS SOUTH
FLORIDA FOR LESSER STORM ACTIVITY. HOWEVER, THE ECMWF SPLITS THE
CUT-OFF LOW DRIFTING THE SOUTHERN PORTION TO THE SOUTH WHICH WOULD
KEEP SOUTH FLORIDA VERY UNSTABLE. FOR NOW, WILL GO WITH THE GFS
SOLUTION AS THIS MODEL HAS BEEN THE MOST CONSISTENT IN ITS FORECAST
WHERE THE ECMWF HAS HAD DIFFERENT SOLUTIONS WITH EACH RUN.
MARINE...
TRANQUIL CONDITIONS OUTSIDE OF ISOLATED STRONG CONVECTION WILL
CONTINUE THROUGH THURSDAY. SOME INCREASE IN A NORTHEAST SWELL IS
EXPECTED LATE IN THE WEEK INTO THE WEEKEND WITH POSSIBLE SEAS
BUILDING TO 7 FEET OVER THE PALM BEACH WATERS.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH DEEP TROPICAL MOISTURE REMAINING IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 81 70 81 / 50 70 50 60
FORT LAUDERDALE 71 81 71 82 / 50 70 50 60
MIAMI 75 81 71 83 / 50 70 50 60
NAPLES 68 85 67 83 / 50 50 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
744 PM EDT WED MAY 1 2013
.AVIATION...
A TROUGH OF LOW PRESSURE THAT BROUGHT SHOWERS AND THUNDERSTORMS
TODAY, WILL CONTINUE TO BRING SOME SHOWER ACTIVITY INTO THE LATE
EVENING HOURS. THIS MEAN VFR TO MVFR CONDITIONS ARE EXPECTED
OVERNIGHT, WITH VFR IN THE MORNING, RETURNING TO A MIX OF VFR AND
MVFR TOMORROW. THIS IS DUE TO ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS EXPECTED TO DEVELOP AROUND MID DAY. WINDS WILL BE
LIGHT AND VARIABLE FOR A WHILE THIS EVENING, BEFORE BECOMING
EASTERLY BETWEEN 5 AND 10 KTS. THEY WILL INCREASE TO 10 TO 15 KTS
TOMORROW MORNING.
&&
.PREV DISCUSSION... /ISSUED 238 PM EDT WED MAY 1 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
LARGE CUT-OFF MID LEVEL LOW CONTINUES TO SLOWLY DRIFT EAST ACROSS
THE SOUTH CENTRAL GULF STATES. A LARGE CLUSTER OF CONVECTION
DEVELOPED ON THE SOUTHERN FRINGES OF THIS LOW AND HAS MOVED EAST
THROUGH EARLY THIS AFTERNOON AND AS OF 1830Z WAS MOVING ACROSS THE
INTERIOR AND TOWARDS THE EAST COAST METRO AREA. ANOTHER CLUSTER OF
CONVECTION IS ALSO CURRENTLY DEVELOPING OVER THE CENTRAL GULF WITH
THE HRRR SHOWING THIS MOVING ACROSS SOUTH FLORIDA THIS EVENING SO
HAVE INCREASED THE POPS FOR THE OVERNIGHT HOURS. AT THE SAME TIME, A
DEEPENING TROUGH INTO THE CENTRAL PLAINS STATES ON THURSDAY WILL
CONTINUE TO DEEPEN AND CUT OFF OVER THE MISSISSIPPI VALLEY WITH
THE SOUTHERN CUT-OFF LOW BECOMING PHASED IN WITH THIS LOW. THIS
KEEPS SOUTH FLORIDA IN RICH TROPICAL FLOW OF AIR THROUGH THE END
OF THE WEEK WITH HIGH CHANCES FOR SHOWERS AND THUNDERSTORMS.
FORECAST SOUNDINGS THROUGH THIS PERIOD LOOK QUITE SIMILAR WITH
PWAT REMAINING WELL ABOVE NORMAL FOR EARLY MAY AND A WEAK WESTERLY
STEERING FLOW. GLOBAL MODELS ARE NOW MORE IN AGREEMENT WITH THE
OVERALL SOLUTION DURING THE NEXT 48 HOURS AND SHOW THE LOW
DRIFTING TO THE SOUTHEAST BEFORE GETTING PHASED IN WITH THE
UPSTREAM DEEPENING TROUGH. THIS ON THURSDAY AND POSSIBLY FRIDAY
WILL DESTABILIZE THE ATMOSPHERE WITH COOLING 500 MB TEMPERATURES.
THE 12Z MFL SOUNDING SHOWED A TEMPERATURE OF -10 CELSIUS AND THE
GFS SHOWS COOLING TO AROUND -12 ON THURSDAY INTO FRIDAY. SO THE
CONTINUED THREAT FOR STRONG STORMS WILL ALSO BE A FACTOR. OF
COURSE THERE WILL ALWAYS BE SOME DAY TO DAY FLUCTUATIONS WITH WEAK
DISTURBANCES MOVING THROUGH THE BASE OF THE TROUGH.
LONG TERM (SATURDAY THROUGH WEDNESDAY)...
THE EXTENDED PORTION OF THE FORECAST CONTINUES TO BE HIGHLY
UNCERTAIN WITH THE GFS AND ECMWF HAVING TWO DIFFERENT SOLUTIONS TO
THE DEEPENING TROUGH. BOTH CUT THIS LOW OFF FROM THE NORTHERN
LATITUDE FLOW AS MENTIONED ABOVE. THE GFS THEN DEVELOPS A MASSIVE
CUT-OFF LOW AND THEN SLOWLY DRIFTS IT TO THE EAST THROUGH THE MIDDLE
OF NEXT WEEK. THIS WOULD TEND TO DRAW A DRIER AIR MASS ACROSS SOUTH
FLORIDA FOR LESSER STORM ACTIVITY. HOWEVER, THE ECMWF SPLITS THE
CUT-OFF LOW DRIFTING THE SOUTHERN PORTION TO THE SOUTH WHICH WOULD
KEEP SOUTH FLORIDA VERY UNSTABLE. FOR NOW, WILL GO WITH THE GFS
SOLUTION AS THIS MODEL HAS BEEN THE MOST CONSISTENT IN ITS FORECAST
WHERE THE ECMWF HAS HAD DIFFERENT SOLUTIONS WITH EACH RUN.
MARINE...
TRANQUIL CONDITIONS OUTSIDE OF ISOLATED STRONG CONVECTION WILL
CONTINUE THROUGH THURSDAY. SOME INCREASE IN A NORTHEAST SWELL IS
EXPECTED LATE IN THE WEEK INTO THE WEEKEND WITH POSSIBLE SEAS
BUILDING TO 7 FEET OVER THE PALM BEACH WATERS.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH DEEP TROPICAL MOISTURE REMAINING IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 81 70 81 / 60 70 50 60
FORT LAUDERDALE 71 81 71 82 / 60 70 50 60
MIAMI 75 81 71 83 / 60 70 50 60
NAPLES 68 85 67 83 / 60 50 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1035 AM EDT TUE APR 30 2013
.DISCUSSION...
MORNING SOUNDINGS SHOW A NEARLY SATURATED AIRMASS WITH SWRLY FLOW
THRU THE H100-H70 LYR...SLIGHTLY DRIER WITH WRLY FLOW ABV H70.
KTBW/KMFL PWAT VALUES BTWN 1.6"-1.7" WITH H50 TEMPS BTWN -10C AND
-12C. RUC ANALYSIS SHOWING A WEAK SPOT LOW IN THE H100-H85 WIND
FIELD OFF THE NE FL COAST. GENTLE S/SWRLY FLOW PREVAILS OVER THE S
HALF OF THE FL PENINSULA BCMG LIGHT WRLY FLOW OVER THE N HALF...
CONVERGENCE ZONE EXTENDING FROM LAKE OKEECHOBEE TO TAMPA BAY.
MOISTURE IS PLENTIFUL WITH H10-H70 MEAN RH VALUES BTWN 80-90PCT AND
SFC DEWPOINTS IN THE M/U60S.
ALOFT...DYNAMIC SUPPORT IS NOT ALL THAT IMPRESSIVE...LITTLE IN THE
WAY OF UPSTREAM MID LVL VORTICITY OR UPR LVL DIVERGENCE. HOWEVER...
MID LVL OMEGA FIELDS ARE STRONGLY NEGATIVE OVER THE S FL
PENINSULA...INDICATING UPWARD VERTICAL MOTION.
AIRMASS IS PRIMED FOR ANOTHER ROUND OF CONVECTION...ABOUT THE ONLY
THING MISSING ACRS THE NRN CWA AT THIS POINT IS SFC HEATING DUE TO
MID/UPR LVL DEBRIS CLOUDS GENERATED BY EARLIER CONVECTION OVER THE W
FL PENINSULA. INDEED...CONVECTION HAS ALREADY FIRED ARND LAKE
OKEECHOBEE WHERE DEBRIS CLOUDS ARE THIN. NOT COINCIDENTALLY...THIS
IS ALSO WHERE THE OMEGA FIELD INDICATES THE STRONGEST LIFT.
LATEST SAT PICS SHOW THE DEBRIS DECK STEADILY ERODING FROM THE WEST
WITH THE CLEARING LINE PUSHING E OF I-75. WEAK WIND FIELDS SHOULD
ALLOW BOTH THE EAST AND WEST COAST SEABREEZES TO DEVELOP ONCE SFC
HEATING SETS IN. ANTICIPATE STORM INITIALIZATION ACRS THE
CENTRAL/NRN CWA BY EARLY AFTN. STRONG CONVECTION PSBL DUE TO COLD
TEMPS ALOFT... ESPECIALLY WHERE MESOSCALE BOUNDARY COLLISIONS OCCUR.
&&
.AVIATION....
THRU 30/18Z...PREVAILING CIGS BTWN FL100-120...LCL MVFR VSBYS/CIGS
IN BRIEF SHRAS S OF KMLB-KISM. AFT 30/18Z...PREVAILING CIGS BTWN
FL080-100...NMRS MVFR SHRAS AND SCT IFR TSRAS ALL SITES CONTG THRU
01/02Z INTERIOR...01/04Z COASTAL...ISOLD +TSRA WITH SFC WND G35KTS
PSBL BTWN 30/19Z-30/23Z.
&&
.MARINE...
OBS FROM THE DATA BUOY/C-MAN NETWORK MEASURING W/SWRLY WINDS AOB
10KTS...SEAS ARND 4FT ALMOST ALL OF WHICH IS DUE TO A 13-14SEC
SWELL. PGRAD FAIRLY TIGHT TO THE SE. HOWEVER...AN INVERTED SFC TROF
CENTERED OFF THE CAROLINA COAST WILL KEEP THE LCL WIND FIELD WEAK
AND DISORGANIZED. LITTLE PROSPECT FOR STRONG WINDS OUTSIDE OF LCL
CONVECTION. WILL REMOVE THE CAUTIONARY STATEMENT WITH THE MORNING
UPDATE...NO OTHER CHANGES NECESSARY.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...PENDERGRAST
AREA FORECAST DISCUSSION
NWS MIAMI FL
119 AM EDT TUE APR 30 2013
.AVIATION...VFR WILL PREVAIL. HOWEVER, A FEW SHOWERS ARE POSSIBLE
ALONG THE ATLANTIC COAST THIS MORNING AND SCATTERED TSTORMS ARE
EXPECTED THIS AFTERNOON. HRRR SHOWS SOME SHOWER DEVELOPMENT ALONG
THE ATLANTIC COAST THIS MORNING AND A FEW ARE ALREADY DEVELOPING,
SO PLACED VCSH ALL EAST COAST TERMINALS FOR THE MORNING. KEPT VCTS
ALL TERMINALS FOR THIS AFTERNOON-EVENING. BRIEF IFR WOULD BE
POSSIBLE SHOULD A DIRECT TSTORM IMPACT OCCUR, AND A COUPLE OF THE
STORMS COULD PRODUCE STRONG DOWNBURST WINDS, BUT PROBABILITIES ARE
TOO LOW TO MENTION ANYTHING MORE THAN VCTS AT THIS TIME. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 825 PM EDT MON APR 29 2013/
UPDATE...
EARLIER SHOWERS AND THUNDERSTORMS HAVE QUICKLY DISSIPATED ACROSS
THE ENTIRE SOUTH FLORIDA AREA WITH LOSS OF HEATING. DECREASED POPS
AREA WIDE TO ACCOUNT FOR THIS. CURRENT RADAR SHOWS A CLUSTER OF
SHOWERS AND THUNDERSTORMS MOVING NORTH FROM CUBA INTO THE FLORIDA
STRAITS. LATEST LOCAL HIGH RESOLUTION MODELS DEPICT SOME OF THIS
ACTIVITY MOVING INTO THE GULF WATERS OVERNIGHT AND INTO EARLY
TUESDAY MORNING. WILL KEEP SLIGHT CHANCE POP ACROSS GULF AND
ATLANTIC WATERS OVERNIGHT. BELIEVE PARTLY TO MOSTLY CLOUDY SKIES
WILL PREVAIL OVERNIGHT WHICH SHOULD KEEP FOG FORMATION CHANCES
LOW. KEPT ANY MENTION OUT OF THE FORECAST FOR NOW. BELIEVE ANY
FOG THAT DOES DEVELOP ACROSS INTERIOR AREAS SHOULD BE VERY
SHALLOW.
PREV DISCUSSION... /ISSUED 806 PM EDT MON APR 29 2013/
AVIATION...
THE WEATHER IS QUIETING DOWN THIS EVENING AFTER A ROUND OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON. CONDITIONS SHOULD BE VFR TONIGHT
WITH WINDS BECOMING LIGHT AND VARIABLE. TOMORROW WILL SEE A REPEAT
OF TODAY. WINDS WILL PICKUP IN THE MORNING OUT OF THE SOUTHEAST
AROUND 10 KTS AND SHOWERS WILL DEVELOP. THEN, IN THE AFTERNOON,
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS SOUTH FLORIDA. GIVEN
THE NATURE OF CONVECTION AND THE UNPREDICTABILITY, HAVE PUT VCTS
IN ALL TAF SITES AT 18Z.
PREV DISCUSSION... /ISSUED 234 PM EDT MON APR 29 2013/
SYNOPSIS...
A LOW PRESSURE TROUGH EXTENDING FROM THE GULF OF MEXICO THROUGH
THE MISSISSIPPI VALLEY WILL REMAIN IN PLACE MOST OF THIS WEEK. FOR
SOUTH FLORIDA...WARM...MOIST AND UNSTABLE AIR AHEAD OF THIS TROUGH
WILL CREATE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
THROUGH THE PERIOD.
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE EVERGLADES EARLY
THIS AFTERNOON. MOVEMENT IS NORTH AND EAST AND EXPECT COVERAGE TO
CONTINUALLY INCREASE THROUGH LATE AFTERNOON. THE MAJORITY OF
ACTIVITY SHOULD REMAIN OVER THE INTERIOR...BUT AT LEAST SCATTERED
SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED FOR BOTH EASTERN
METRO AREAS AND NAPLES. CAPE VALUES IN EXCESS OF 1000 J/KG HAS
OVERCOME MODEST MID-LEVEL INHIBITION. DESPITE WEAK LAPSE RATES AND
UNIMPRESSIVE 0-6KM SHEAR...THE STRONGEST UPDRAFTS WILL BE CAPABLE
OF PRODUCING HAIL AS WELL AS STRONG/POSSIBLY DAMAGING
MICROBURSTS...PARTICULARLY NEAR OUTFLOW/SEABREEZE INTERACTIONS. WITH
PWAT VALUES APPROACHING 1.5 INCHES...TORRENTIAL DOWNPOURS WILL
OCCUR AND LOCALIZED FLOODING CANT BE RULED OUT. OUTSIDE OF
CONVECTION...TEMPERATURES ARE IN THE 80S.
PRECIPITATION THIS AFTERNOON IS A RESULT OF A MOIST ATMOSPHERE AND
OVERALL DIFFLUENT FLOW IN ADVANCE OF MID/UPPER-LEVEL TROUGH OVER
THE MISSISSIPPI VALLEY. IN ADDITION...H3 JET MAX MOVING THROUGH
GULF WILL PLACE SOUTH FLORIDA IN CONVECTIVELY-FAVORED ASCENT BY
THIS EVENING. WITH INSTABILITY DIURNALLY WANING OVERNIGHT...SEVERE
STORMS ARE NOT EXPECTED...BUT SHOWERS MAY CONTINUE AND TSTMS ARE
POSSIBLE OVER THE WARM ATLANTIC WATERS TONIGHT.
ALOFT...SYNOPTIC PATTERN WILL STALL THROUGH AT LEAST MID-WEEK.
THUS...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
FORECAST...ESPECIALLY DURING THE AFTERNOONS...WITH A SIGHT RISK
FOR STRONG/SEVERE...CONVECTION. NEAR THE SURFACE...A LOW PRESSURE
TROUGH OVER NORTHERN FLORIDA TODAY WILL GRADUALLY MOVE SOUTH AND
INTO SOUTH FLORIDA BY WEDNESDAY. THIS MAY SERVE TO INCREASE
CONVECTION ON WEDNESDAY...BUT INCREASED CLOUDS COULD LIMIT
INSTABILITY AND STORM INTENSITY. TEMPERATURES DURING THE PERIOD
WILL BE SLIGHTLY ABOVE AVERAGE.
LONG TERM /THURSDAY THROUGH SUNDAY/...
THE LONG RANGE MODELS ARE SHOWING TWO UPPER LEVEL LOWS DEVELOPING
LATE THIS WEEK INTO NEXT WEEKEND. ONE OF THE UPPER LEVEL LOWS
SHOULD DEVELOP OVER THE CENTRAL UNITED STATES...WHILE THE OTHER
UPPER LEVEL LOW SHOULD DEVELOP OVER THE MID ATLANTIC WATERS. THIS
WILL ALLOW FOR THE RIDGE OF HIGH PRESSURE TO DEVELOP OVER THE
SOUTHEASTERN UNITED STATES AND INTO THE FLORIDA PENINSULA. THIS IN
TURN WILL ALLOW FOR DRIER AIR TO WORK INTO SOUTH FLORIDA FROM THE
NORTH. SO WILL SHOW A GRADUAL LOWERING OF POPS LATE THIS WEEK
INTO NEXT WEEKEND WITH THE BEST CHANCE STILL OVER THE INTERIOR
AREAS EACH DAY...DUE TO THE SEA BREEZES DEVELOPING AND PUSHING
INLAND EACH DAY.
MARINE...
SOUTHEAST WINDS OF 10-15 KTS TODAY WILL BECOME SOUTH AT 10-15 KTS
ON TUESDAY. A WEAK LOW LEVEL BOUNDARY MAY SHIFT WINDS TO THE NORTH
ON WEDNESDAY. THROUGH AT LEAST MID-WEEK...SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE EXPECTED. SOME OF THIS ACTIVITY MAY
BE STRONG...AND SPECIAL MARINE WARNINGS MAY BE NEEDED.
FIRE WEATHER...
RELATIVE HUMIDITY VALUES WILL BE ABOVE 40 PERCENT MOST OF THIS
WEEK AS A MOIST AND UNSTABLE ATMOSPHERE RESIDES OVER SOUTH
FLORIDA. PATCHY INLAND FOG CANT BE RULED OUT EACH OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 84 70 82 / 40 50 40 60
FORT LAUDERDALE 74 85 72 84 / 30 50 40 50
MIAMI 73 86 72 85 / 30 50 40 50
NAPLES 70 86 69 84 / 20 40 40 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
224 PM CDT TUE APR 30 2013
.DISCUSSION...
ISSUED 205 PM CDT TUE APR 30 2013
WARM AND DRY CONDITIONS TO HOLD THRU WED NIGHT WITH INCREASING
RAIN CHANCES DURING THE DAY THURSDAY...AND ESPECIALLY THURSDAY
NIGHT THROUGH FRIDAY NIGHT AS AN UPPER LEVEL SYSTEM CLOSES OFF
OVER THE SOUTHERN PLAINS FRIDAY AND SLOWLY MOVES NORTHEAST THRU
THE MIDWEST THIS WEEKEND.
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
NO SIGNIFICANT MODEL DIFFERENCES SEEN THRU THURSDAY MORNING AS THE
FRONTAL BOUNDARY THAT IS OUT OVER WEST CENTRAL IOWA WILL ONLY SLOWLY
EDGE EAST OVER THE NEXT 36 TO 48 HOURS AND NOT GET INTO OUR AREA
UNTIL THURSDAY. UNTIL THEN...A MILD SOUTHERLY FLOW WILL CONTINUE THRU
AT LEAST THURSDAY MORNING MOST AREAS. MODELS HAVE BEEN CONSISTENTLY
SHOWING A COOLING TREND AT 850 MB TOMORROW...ALBEIT 2 TO 3 DEGREES...BUT
THAT`S ENOUGH TO SUPPORT TEMPS A FEW DEGREES COOLER THAN THIS AFTERNOON`S
HIGH TEMPS. WENT WITH THE WARMER GUID THURSDAY BASED ON THE SLOWER FRONTAL
MOVEMENT WITH THE COLDEST TEMPS ALOFT CLOSE TO THE CLOSED LOW AT 500
MB...WHICH BY FRIDAY NIGHT WILL BE OVER SOUTH-CENTRAL MISSOUR.
MODELS CONTINUE TO INDICATE MOST OF THE PRECIP TO BE POST FRONTAL...AND
BASED ON THE SLOWER TIMING OF THE BOUNDARY INTO THE FORECAST AREA ON
THURSDAY...WILL BUMP TEMPS UP AND HAVE THE HIGHEST POPS STARTING THU
AFTERNOON AND ESPECIALLY THU NIGHT. BEST CHANCE FOR ANY CONVECTION
LOOK TO BE RIGHT ALONG OR IMMEDIATELY BEHIND THE FRONTAL BOUNDARY
WITH MOST OF THE FORECAST SOUNDINGS SHOWING LIMITED SURFACE BASE/MU
CAPES. FORECAST SOUNDINGS SUGGEST THE DEEPEST MOISTURE OVER OUR AREA
FRIDAY INTO FRIDAY NIGHT RESULTING IN OCCASIONAL SHOWERS...POSSIBLY
SOME THUNDER...ESPECIALLY OVER THE EAST CLOSEST TO THE BOUNDARY.
LONG TERM...SATURDAY THROUGH TUESDAY
THE UPPER LOW FORECAST TO TRACK SLOWLY NNE ACRS MISSOURI SATURDAY
AND SUNDAY...KEEPING RAIN CHANCES GOING THRU THE WEEKEND WITH SLIGHTLY
COOLER TEMPERATURES...ESPECIALLY ON SUNDAY WHEN WE WILL BE CLOSEST
TO THE UPPER LOW. AS THE LOW DRIFTS FURTHER NNE INTO NORTHERN IL BY
LATE SUNDAY NIGHT OR MONDAY...IT WOULD APPEAR OUR PRECIP CHANCES
WOULD BECOME MORE DIURNAL IN NATURE WITH THE BETTER CHANCES DURING
PEAK HEATING IN THE AFTERNOON AND EARLY EVENING...AND THEN A LULL/OR
DROP OFF IN POPS AT NIGHT. WILL TRY TO TREND IN THAT DIRECTION BASED
ON THE FURTHER NORTH FORECAST FROM THE ECMWF AND CANADIAN MODELS.
AS FAR AS RAINFALL AMOUNTS ARE CONCERNED...IT APPEARS THE PROBABILITY
FOR THE MOST WIDESPREAD RAINS WILL BE HIGHEST LATER THURSDAY NIGHT
INTO FRIDAY NIGHT WITH QPF VALUES OF 1-2 INCHES POSSIBLE. WILL HAVE
TO SEE HOW MUCH...IF ANY...THE MOISTURE TRANSPORT WILL BE TAKEN UP
BY AN UPPER LEVEL LOW AND SFC WAVE ALONG THE GULF COAST FRIDAY AND
SATURDAY. SEE THE HYDROLOGY SECTION BELOW FOR SOME PRELIMINARY INFO
ON HOW THIS RAINFALL MAY AFFECT SOME OF THE RIVERS IN OUR AREA.
SMITH
&&
.AVIATION...
ISSUED 1235 PM CDT TUE APR 30 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE ENTIRE TAF PERIOD IN
CENTRAL AND EAST ILLINOIS.
THE MAIN CONCERN FOR TODAY WILL BE SURFACE WIND GUSTS WITH THE
INCREASING GRADIENT IN WESTERN AND CENTRAL ILLINOIS AHEAD OF A
SLOW MOVING COLD FRONT IN CENTRAL IOWA. BUFKIT MOMENTUM TRANSFER
FROM THE NAM AND SURFACE GUST FORECASTS FROM THE HRRR AND RAPID
REFRESH MODELS ALL INDICATE THAT THE HIGHEST POTENTIAL FOR WIND
GUSTS WILL BE ALONG AND WEST OF I-55 WHERE THE BEST MIXING AND
WARMEST TEMPERATURES ARE EXPECTED. AS A RESULT...WILL REMOVE GUSTS
FROM THE TAFS FOR KDEC/KCMI. THE WIND WILL SETTLE DOWN JUST BEFORE
SUNSET AS THE LOWER ATMOSPHERE BEGINS TO DECOUPLE AND THE
NIGHTTIME INVERSION SETS UP.
VERY LITTLE IN THE WAY OF CLOUD COVER IS ANTICIPATED WITH DRY LOW
LEVELS OF THE ATMOSPHERE AND CONVECTIVE TEMPS CLOSE TO 90. ONLY
SOME SCATTERED HIGH CLOUDS ARE EXPECTED AT TIMES THIS AFTERNOON
AND TONIGHT...WITH A BIT OF CUMULUS ANTICIPATED LATER WEDNESDAY
MORNING AS LOW LEVEL MOISTURE JUST STARTS TO INCREASE.
MILLER
&&
.HYDROLOGY...
ISSUED 205 PM CDT TUE APR 30 2013
CURRENT INDICATIONS SUGGEST THAT BASED ON A BASIN AVERAGE OF 1-1.5"
OF RAIN INTO SATURDAY...THE ILLINOIS BASIN WOULD NOT SEE MUCH OF A
RESPONSE OTHER THAN TO SLOW DOWN THE RATE OF FALL AT OUR FORECAST
SITES INTO EARLY NEXT WEEK. ALONG THE SPOON AND SANGAMON BASINS...WE
COULD SEE RIVER LEVELS RISE IF WE DID RECEIVE THIS MUCH RAINFALL...BUT
IT APPEARS MOST AREAS WILL REMAIN BELOW FLOOD STAGE INTO EARLY NEXT
WEEK. STILL SOME UNCERTAINTY WITH RESPECT TO THE TRACK OF THE UPPER
LEVEL SYSTEM AND FRONTAL BOUNDARY ACROSS OUR AREA LATE IN THE WEEK
AND INTO THE WEEKEND...AS A RESULT...THE AXIS OF HEAVIEST RAINS WILL
NEED TO BE ADJUSTED SOME AS THE STORM SYSTEM DRAWS CLOSER TO THE
MIDWEST.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1235 PM CDT TUE APR 30 2013
.DISCUSSION...
ISSUED 1055 AM CDT TUE APR 30 2013
ONLY MADE MINOR TWEAKS TO THE FORECAST/GRIDS FOR THIS
AFTERNOON...MAINLY TO BUMP UP TEMPS A COUPLE OF DEGREES IN WEST
CENTRAL IL. MORNING SOUNDINGS AROUND THE MIDWEST INDICATED THAT
WITH PLENTY OF MIXING...WHICH IS ALREADY OCCURRING...THERE IS
ENOUGH WARM AIR IN THE LOW LEVELS TO ALLOW TEMPS TO CLIMB WELL
INTO THE LOWER TO MIDDLE 80S.
THE MIXING WILL ALSO RESULT IN ANOTHER DAY OF GUSTY SOUTH WINDS.
ALSO TWEAKED THE GUSTS UP A BIT FOR THIS AFTERNOON. OTHERWISE...
DRY WILL BE THE MAIN WEATHER WORD FOR TODAY
&&
.AVIATION...
ISSUED 1235 PM CDT TUE APR 30 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE ENTIRE TAF PERIOD IN
CENTRAL AND EAST ILLINOIS.
THE MAIN CONCERN FOR TODAY WILL BE SURFACE WIND GUSTS WITH THE
INCREASING GRADIENT IN WESTERN AND CENTRAL ILLINOIS AHEAD OF A
SLOW MOVING COLD FRONT IN CENTRAL IOWA. BUFKIT MOMENTUM TRANSFER
FROM THE NAM AND SURFACE GUST FORECASTS FROM THE HRRR AND RAPID
REFRESH MODELS ALL INDICATE THAT THE HIGHEST POTENTIAL FOR WIND
GUSTS WILL BE ALONG AND WEST OF I-55 WHERE THE BEST MIXING AND
WARMEST TEMPERATURES ARE EXPECTED. AS A RESULT...WILL REMOVE GUSTS
FROM THE TAFS FOR KDEC/KCMI. THE WIND WILL SETTLE DOWN JUST BEFORE
SUNSET AS THE LOWER ATMOSPHERE BEGINS TO DECOUPLE AND THE
NIGHTTIME INVERSION SETS UP.
VERY LITTLE IN THE WAY OF CLOUD COVER IS ANTICIPATED WITH DRY LOW
LEVELS OF THE ATMOSPHERE AND CONVECTIVE TEMPS CLOSE TO 90. ONLY
SOME SCATTERED HIGH CLOUDS ARE EXPECTED AT TIMES THIS AFTERNOON
AND TONIGHT...WITH A BIT OF CUMULUS ANTICIPATED LATER WEDNESDAY
MORNING AS LOW LEVEL MOISTURE JUST STARTS TO INCREASE.
MILLER
&&
.PREV DISCUSSION...
ISSUED 321 AM CDT TUE APR 30 2013
MAIN CONCERN THIS FORECAST PACKAGE WILL BE ONSET OF PCPN LATER
THIS WEEK...ASSOCIATED WITH THE FRONTAL SYSTEM THAT IS SLOWLY
MOVING INTO THE AREA. MODELS SEEM SIMILAR WITH TIMING OF THE
FRONT...BUT DIFFER WITH WHEN PCPN WILL BEGIN IN THE AREA. ALL
MODELS HAVE MOST OF THE PCPN POST-FRONTAL. HOWEVER...SOME HAVE
SOME LIGHT PCPN AHEAD OF THE FRONT. ALL MODELS AGREE ON THE
OVERALL UPPER LEVEL PATTERN WITH A TROUGH DEVELOPING IN THE PLAINS
TOWARD END OF THE WEEK...BUT THEN DIFFER IN THE EXTENDED WITH
LOCATION AND MOVEMENT OF THE CUTOFF LOW THAT ALL MODELS DEVELOP.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
MODELS SIMILAR WITH FRONT THROUGH ABOUT 48HRS ONLY...BUT THEN GFS
BECOMES QUICKER THAN NAM/ECMWF. THEN BY THURSDAY THE NAM BECOMES
THE QUICKEST AND THE ECMWF IS SLOWEST. THESE DIFFERENCES GET
REFLECTED ON WHEN PCPN STARTS. BELIEVE SLOWEST SOLUTION IS
BEST...BUT HAVE TO BLEND WITH SURROUNDING OFFICES SO WENT WITH
JUST CHC POPS FOR THURSDAY MORNING...AND THEN LIKELY IN THE WEST
FOR THE AFTERNOON. PRIOR TO THUR CONDITIONS WILL BE DRY FOR TODAY
THROUGH WED AND THEN A CHC OF PCPN NORTHWEST OF THE IL RIVER FOR
WED NIGHT. ALL MODELS AGREE PCPN WILL BE LIKELY FOR THUR NIGHT.
AHEAD OF THE FRONT...PCPN TYPE LOOKS TO BE THUNDERSTORMS BUT ONCE
FRONT MOVES THROUGH THE AREA STORMS SHOULD BECOME MORE ISOLATED
AND MAIN PCPN TYPE WILL BE SHOWERS. RAIN SHOULD BE MODERATE AS
WELL GIVEN THE SLOW NATURE OF THE PCPN OVER THE AREA THROUGH THE
PERIOD.
TEMPS WILL BE QUITE WARM TODAY AND TOMORROW AS CWA SITS IN THE
WARM SECTOR. WINDS COULD ALSO BE BREEZY AGAIN TODAY...AS
YESTERDAY. ONCE PCPN AND CLOUD COVER MOVES INTO THE AREA TEMPS
WILL THEN COOL...DROPPING TO BELOW NORMAL FOR EARLY MAY.
LONG TERM...FRIDAY THROUGH MONDAY
WITH EXTENDED MODELS DIFFERING ON HOW THE SFC FEATURES WILL
PROGRESS AFTER THURSDAY NIGHT AND DIFFER ON WHEN AND WHERE THE
UPPER LEVEL LOW WILL MOVE TO...HAVE DECIDED TO JUST FOLLOW THE
BLENDED MODEL FORECAST. THIS FORECAST KEEPS A CHC OF PCPN IN THE
FORECAST THROUGH MONDAY. ALL PCPN SHOULD BE IN THE FORM OF
SHOWERS.
TEMPS WILL REMAIN ON THE COOL SIDE WITH CONTINUED PCPN AND SOME
CLOUD COVER THROUGH THE PERIOD. IN ADDITION...WITH THE UPPER LEVEL
SYSTEM BEING EITHER OVER US OR NEAR US INTO THE WEEKEND...COOL MID
LEVEL TEMPS WILL ALSO HELP TO KEEP US ON THE COOL SIDE FOR
AFTERNOON HIGHS. TEMPS COULD BEGIN TO WARM BACK TO NORMAL BY
BEGINNING OF NEXT WEEK...BUT ITS TOO SOON TO BE OPTIMISTIC WITH
THAT AS MORE PCPN IS POSSIBLE THE FIRST PART OF NEXT WEEK.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
253 AM CDT TUE APR 30 2013
.DISCUSSION...
939 PM...EVENING UPDATE...CONVECTIVE TRENDS OVERNIGHT REMAIN
UNCERTAIN. MASSIVE STORM DEVELOPED SOUTHWEST OF DBQ 1-2 HOURS AGO
PRODUCING UP TO TENNIS BALL SIZED HAIL. THIS STORM HAS SINCE
WEAKENED AS IT MOVES INTO SOUTHWEST WI. ADDITIONAL ACTIVITY ALSO
BUBBLING ACROSS CENTRAL IA AND SHORT TERM/HIGH RES GUIDANCE SEEMS
TO FOCUS ON THIS AREA FOR FURTHER DEVELOPMENT LATE THIS EVENING AS
THE LOW LEVEL JET DEVELOPS/INCREASES...WITH THIS ACTIVITY LIFTING
NORTH INTO SOUTH/CENTRAL WI OVERNIGHT. AT THE SAME TIME...DECENT
AGREEMENT FOR ADDITIONAL DEVELOPMENT OVER LAKE MICHIGAN WHICH
DEVELOPS SOUTHEAST INTO NORTHWEST INDIANA IN THE PREDAWN HOURS
TOWARD SUNRISE. WITH EITHER OF THESE SCENARIOS PLAUSIBLE...ITS
POSSIBLE THAT MUCH OF THE CWA COULD REMAIN DRY OVERNIGHT AND INTO
TUESDAY MORNING. BUT ISOLATED ACTIVITY CURRENTLY DEVELOPING
SOUTHEAST OF DBQ WHICH WILL NEED TO BE MONITORED IN THE SHORT
TERM. THUS GIVEN LOW CONFIDENCE...HAVE MAINTAINED LOW CHANCE POPS
FOR AREAS GENERALLY ALONG/NORTH OF THE I-80 CORRIDOR BUT HAVE
INCLUDED SOME TIMING/TRENDS IN THE GRIDS...ALL OF WHICH WILL
LIKELY NEED ADJUSTMENTS THROUGH THE NIGHT. ANY ORGANIZED CELLS
THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL. CMS
//PREV DISCUSSION...
323 PM CDT
MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.
NEAR TERM...TONIGHT-WEDNESDAY
SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.
ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.
LONGER TERM...THURSDAY-MONDAY
MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW CHANCES FOR SHRA/TSRA OVERNIGHT.
* GUSTY SOUTHERLY WINDS AROUND 25KT OR SO TUESDAY AFTERNOON.
BMD
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE LIES OVER THE DAKOTAS THIS EVENING WITH SOUTHERLY FLOW
IN PLACE ACROSS NORTHERN ILLINOIS. MODERATE INSTABILITY LIES OVER
THE AREA THIS EVENING HOWEVER THE BEST FOCUS FOR FORCING IS EXPECTED
TO REMAIN WEST AND NORTHWEST OF THE TERMINALS THROUGH THE NIGHT. A
60 KT LOW LEVEL JET IS EXTENDING INTO WESTERN IOWA AND IS CURRENTLY
THE FOCUS FOR CONVECTION OFF TO OUR WEST. STORM MOTIONS ARE EXPECTED
TO BE SLIGHTLY NORTH OF EAST OVERNIGHT...AND THE JET IS EXPECTED TO
PROPAGATE NORTHEAST INTO SOUTHERN WISCONSIN IN THE PREDAWN HOURS.
CONSIDERING THESE FACTORS...IT SEEMS INCREASINGLY UNLIKELY THAT
THUNDERSTORMS WILL DEVELOP IN A FAVORABLE POSITION TO MOVE ACROSS
THE ROCKFORD/CHICAGO TERMINALS. THAT SAID...WITH BROAD ASCENT FROM
WARM ADVECTION ACROSS THE AREA...CANNOT RULE OUT SOMETHING ISOLATED
DEVELOPING CLOSER TO THE TERMINALS TONIGHT. GIVEN THE LOW
PROBABILITY OF THIS OCCURRING AND THE LIKELY ISOLATED NATURE IF IT
DOES OCCUR...WILL PULL MENTION OF THUNDER FROM THE TAFS FOR THE
REMAINDER OF THE OVERNIGHT HOURS.
MAIN CONCERN DURING THE DAY TUESDAY WILL BE WINDS. DEEP MIXING IS
EXPECTED TO OCCUR WHICH SHOULD HELP BRING DOWN WINDS IN THE MID TO
UPPER 20 KT RANGE...POSSIBLY EVEN 30 KTS AT TIMES. WIND SHOULD
PRIMARILY BE IN THE 190-210 DIRECTION TOMORROW DURING THE DAY.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE IN TSRA/SHRA IMPACTING THE TERMINALS
TONIGHT...MEDIUM CONFIDENCE IN DRY FORECAST.
* HIGH CONFIDENCE IN WINDS 170-210 THROUGH PERIOD...MEDIUM
CONFIDENCE IN WIND SPEEDS.
* HIGH CONFIDENCE IN VFR CONDITIONS THROUGH PERIOD.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.
THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.
FRIDAY...SHRA LIKELY. MVFR LIKELY.
SATURDAY...CHANCE SHRA. MVFR POSSIBLE.
SUNDAY...SLIGHT CHANCE SHRA.
MDB
&&
.MARINE...
251 AM CDT
INCREASING SOUTHERLY FLOW TO AROUND 30 KT IS EXPECTED ACROSS LAKE
MICHIGAN TODAY AS DEEP AREA OF LOW PRESSURE OVER SOUTH DAKOTA EARLY
THIS MORNING LIFTS NORTHEAST INTO CANADA. A SMALL CRAFT ADVISORY
WILL BE HOISTED THIS MORNING AS WINDS ARE ALREADY GUSTING INTO THE
LOW 20 KT RANGE OVERNIGHT. MOIST ADVECTION OF MID TO UPPER 50
DEWPOINT AIR OVER THE LAKE WILL KEEP THE THREAT FOR FOG OVER THE
LAKE THROUGH THE DAY TODAY. STRONG HIGH PRESSURE BUILDS ACROSS THE
CANADIAN PRAIRIES...WHILE THE COLD FRONT EXTENDING SOUTH FROM THE
LOW MOVING OVER HUDSON BAY WILL GRADUALLY PUSH SOUTH ACROSS LAKE
MICHIGAN. EXPECT STRONG SOUTHERLY FLOW AHEAD OF THE FRONT TO
BECOME STRONG NIGHTLY BEHIND THE FRONT...AGAIN TO AROUND 30 KT.
TIMING AND SPEED OF THE FRONTAL PASSAGE CONTINUES TO REMAIN
UNCERTAIN HOWEVER.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1230 AM CDT TUE APR 30 2013
.DISCUSSION...
939 PM...EVENING UPDATE...CONVECTIVE TRENDS OVERNIGHT REMAIN
UNCERTAIN. MASSIVE STORM DEVELOPED SOUTHWEST OF DBQ 1-2 HOURS AGO
PRODUCING UP TO TENNIS BALL SIZED HAIL. THIS STORM HAS SINCE
WEAKENED AS IT MOVES INTO SOUTHWEST WI. ADDITIONAL ACTIVITY ALSO
BUBBLING ACROSS CENTRAL IA AND SHORT TERM/HIGH RES GUIDANCE SEEMS
TO FOCUS ON THIS AREA FOR FURTHER DEVELOPMENT LATE THIS EVENING AS
THE LOW LEVEL JET DEVELOPS/INCREASES...WITH THIS ACTIVITY LIFTING
NORTH INTO SOUTH/CENTRAL WI OVERNIGHT. AT THE SAME TIME...DECENT
AGREEMENT FOR ADDITIONAL DEVELOPMENT OVER LAKE MICHIGAN WHICH
DEVELOPS SOUTHEAST INTO NORTHWEST INDIANA IN THE PREDAWN HOURS
TOWARD SUNRISE. WITH EITHER OF THESE SCENARIOS PLAUSIBLE...ITS
POSSIBLE THAT MUCH OF THE CWA COULD REMAIN DRY OVERNIGHT AND INTO
TUESDAY MORNING. BUT ISOLATED ACTIVITY CURRENTLY DEVELOPING
SOUTHEAST OF DBQ WHICH WILL NEED TO BE MONITORED IN THE SHORT
TERM. THUS GIVEN LOW CONFIDENCE...HAVE MAINTAINED LOW CHANCE POPS
FOR AREAS GENERALLY ALONG/NORTH OF THE I-80 CORRIDOR BUT HAVE
INCLUDED SOME TIMING/TRENDS IN THE GRIDS...ALL OF WHICH WILL
LIKELY NEED ADJUSTMENTS THROUGH THE NIGHT. ANY ORGANIZED CELLS
THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL. CMS
//PREV DISCUSSION...
323 PM CDT
MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.
NEAR TERM...TONIGHT-WEDNESDAY
SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.
ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.
LONGER TERM...THURSDAY-MONDAY
MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW CHANCES FOR SHRA/TSRA OVERNIGHT.
* GUSTY SOUTHERLY WINDS AROUND 25KT OR SO TUESDAY AFTERNOON.
BMD
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE LIES OVER THE DAKOTAS THIS EVENING WITH SOUTHERLY FLOW
IN PLACE ACROSS NORTHERN ILLINOIS. MODERATE INSTABILITY LIES OVER
THE AREA THIS EVENING HOWEVER THE BEST FOCUS FOR FORCING IS EXPECTED
TO REMAIN WEST AND NORTHWEST OF THE TERMINALS THROUGH THE NIGHT. A
60 KT LOW LEVEL JET IS EXTENDING INTO WESTERN IOWA AND IS CURRENTLY
THE FOCUS FOR CONVECTION OFF TO OUR WEST. STORM MOTIONS ARE EXPECTED
TO BE SLIGHTLY NORTH OF EAST OVERNIGHT...AND THE JET IS EXPECTED TO
PROPAGATE NORTHEAST INTO SOUTHERN WISCONSIN IN THE PREDAWN HOURS.
CONSIDERING THESE FACTORS...IT SEEMS INCREASINGLY UNLIKELY THAT
THUNDERSTORMS WILL DEVELOP IN A FAVORABLE POSITION TO MOVE ACROSS
THE ROCKFORD/CHICAGO TERMINALS. THAT SAID...WITH BROAD ASCENT FROM
WARM ADVECTION ACROSS THE AREA...CANNOT RULE OUT SOMETHING ISOLATED
DEVELOPING CLOSER TO THE TERMINALS TONIGHT. GIVEN THE LOW
PROBABILITY OF THIS OCCURRING AND THE LIKELY ISOLATED NATURE IF IT
DOES OCCUR...WILL PULL MENTION OF THUNDER FROM THE TAFS FOR THE
REMAINDER OF THE OVERNIGHT HOURS.
MAIN CONCERN DURING THE DAY TUESDAY WILL BE WINDS. DEEP MIXING IS
EXPECTED TO OCCUR WHICH SHOULD HELP BRING DOWN WINDS IN THE MID TO
UPPER 20 KT RANGE...POSSIBLY EVEN 30 KTS AT TIMES. WIND SHOULD
PRIMARILY BE IN THE 190-210 DIRECTION TOMORROW DURING THE DAY.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE IN TSRA/SHRA IMPACTING THE TERMINALS
TONIGHT...MEDIUM CONFIDENCE IN DRY FORECAST.
* HIGH CONFIDENCE IN WINDS 170-210 THROUGH PERIOD...MEDIUM
CONFIDENCE IN WIND SPEEDS.
* HIGH CONFIDENCE IN VFR CONDITIONS THROUGH PERIOD.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...LOW SHRA/TSRA CHANCES INCREASE LATE.
THURSDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.
FRIDAY...SHRA LIKELY. MVFR LIKELY.
SATURDAY...CHANCE SHRA. MVFR POSSIBLE.
SUNDAY...SLIGHT CHANCE SHRA.
MDB
&&
.MARINE...
205 PM CDT
A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.
THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1218 AM EDT TUE APR 30 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 315 PM EDT MON APR 29 2013
A DRY AND WARM WEATHER PATTERN HAS BEGUN ACROSS CENTRAL INDIANA
THIS AFTERNOON AND WILL PERSIST THROUGH MID-WEEK. THAT IS WHEN A
BROAD UPPER LEVEL CUTOFF LOW WILL BECOME ANCHORED OVER MUCH OF THE
REGION BRINGING SCATTERED SHOWERS AND THUNDERSTORMS ON THURSDAY
AND FRIDAY. THUNDERSTORM POTENTIAL WILL COME TO AN END BY FRIDAY
NIGHT...BUT RAIN SHOWERS WILL CONTINUE INTO MONDAY AS THE
AFOREMENTIONED UPPER LOW TRACKS ACROSS THE MID-ATLANTIC.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 946 PM EDT MON APR 29 2013
FORECAST IS RUNNING ON TRACK AS MID AND HIGH CLOUDS ARE MOVING
INTO THE NORTHERN AND CENTRAL COUNTIES FROM DEVELOPMENT ACROSS
NORTHERN ILLINOIS AND IOWA. HRRR AND RAP STILL KEEP ALL CONVECTION
WELL TO THE NORTH. GOING LOWS IN THE LOW TO MID 50S LOOK GOOD. A
LITTLE CONCERN THAT PATCHY FOG COULD DEVELOP IN THE SOUTHEAST
WHERE CLOUDS WERE LATE TO LEAVE AND WILL BE LATE TO ARRIVE AND
WINDS SHOULD BE A LITTLE LIGHTER...BUT SOUNDINGS DON/T LOOK TOO
FAVORABLE AND DEW POINT DEPRESSIONS ARE STILL PRETTY LARGE. THUS
THOUGHT CHANCE FOR FOG IS STILL LOW ENOUGH AT THIS TIME TO LEAVE
OUT OF FORECAST.
&&
.SHORT TERM /TOMORROW THROUGH THURSDAY/...
ISSUED AT 315 PM EDT MON APR 29 2013
THE FOCUS OF THE SHORT TERM PERIOD IS THE APPROACHING UPPER LEVEL
CUTOFF LOW.
MODELS CONTINUE TO TREND TOWARD A DRY FORECAST THROUGH WEDNESDAY
AS A RIDGE OF HIGH PRESSURE SETS UP OVER THE OHIO VALLEY AND
NORTHEAST. THIS RIDGE WILL BLOCK THE UPPER LEVEL LOW FROM
ENTERING CENTRAL INDIANA UNTIL THURSDAY. FOR NOW...HAVE SLIGHT
CHANCE POPS OVER THE EASTERN COUNTIES AND CHANCE POPS ELSEWHERE
STARTING THURSDAY MORNING. HOWEVER...WOULD NOT BE SURPRISED IF
TIMING OF PRECIP ONSET GETS PUSHED BACK FURTHER.
TEMPS...TRENDED TOWARD THE WARMER GFS FOR TOMORROW...BUT BY
WEDNESDAY...THE NAM FINALLY STARTS PICKING UP ON THE WARMING
TREND. AS A RESULT...WAS ABLE TO GO WITH A MAVMOS BLEND LATE IN
THE SHORT TERM PERIOD. THIS PUTS HIGHS IN THE LOW 80S AND
OVERNIGHT LOWS GENERALLY IN THE UPPER 50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 255 PM EDT MON APR 29 2013
FOCUS FOR THE EXTENDED REMAINS ON THE EXPECTED DEVELOPMENT OF A
LARGE AND UNUSUALLY STRONG CUTOFF UPPER LOW FOR EARLY MAY ACROSS THE
MIDWEST AND POTENTIAL IMPACTS TO CENTRAL INDIANA. MODELS ARE IN
BETTER AGREEMENT TODAY WITH INITIALLY CUTTING OFF THE UPPER LOW OVER
THE CENTRAL PLAINS ON FRIDAY AS THE BROAD POLAR TROUGH AMPLIFIES.
WHERE THE SYSTEM GOES AFTER THAT THOUGH REMAINS A BIG MYSTERY AND
HINGES TO SOME DEGREE ON POTENTIAL INTERACTION AND PHASING WITH AN
UPPER LOW ALONG THE GULF COAST.
12Z OP GFS CONTINUES TO WAFFLE ON ITS TRACK AND HAS COME IN MUCH
FURTHER SOUTH/EAST WITH THE PROGRESSION OF THE UPPER LOW THROUGH THE
EXTENDED PUTTING IT IN THE CENTRAL APPALACHIANS BY MONDAY NIGHT. 12Z
GGEM OUT INTO THE WEEKEND ALSO APPEARS TO BE TRENDING IN THE
DIRECTION OF THE GFS TRACK. CLOSER ANALYSIS SHOWING THAT BOTH OF
THESE MODELS ARE DEPICTING A STRONGER/SLOWER UPPER LOW ALONG THE
GULF COAST AND CONSEQUENTLY GREATER INTERACTION BETWEEN THE TWO
FEATURES. 12Z ECMWF IS SUPPORTED BY THE UKMET...MAINTAINING A
NORTHERLY TRACK TO THE UPPER LOW INTO THE NORTHERN GREAT LAKES BY
MONDAY BEFORE BECOMING ABSORBED BY A DEEPENING TROUGH OVER WESTERN
CANADA. 12Z GFS ENSEMBLES ONCE AGAIN PROVIDE NO HELP TODAY...
INDICATING WIDE VARIANCE ON THE UPPER LOW TRACK BETWEEN ITS MEMBERS
OVER THE WEEKEND.
CONTINUE TO FAVOR A TRACK CLOSER TO THE ECMWF SOLUTION PARTLY
BECAUSE IT HAS BEEN FAR AND AWAY THE MOST CONSISTENT MODEL WITH
RESPECT TO THE UPPER LOW OVER THE LAST FEW DAYS...AND BECAUSE THE OP
GFS/GGEM TRACK ACROSS THE SOUTHEAST STATES IS HIGHLY UNUSUAL. EVEN
WITH GREATER INTERACTION WITH THE UPPER WAVE ALONG THE GULF
COAST...DO NOT ANTICIPATE THE PARENT UPPER LOW TO BE PULLED THAT FAR
S/E. HAVE DEVIATED LITTLE FROM ALLBLEND WITH SUCH LOW CONFIDENCE ON
THE UPPER LOW TRACK AT THIS POINT...AND WILL CONTINUE TO CARRY POPS
THROUGH THE ENTIRE EXTENDED. HIGHEST CONFIDENCE IN WIDESPREAD
RAINFALL REMAINS ON FRIDAY/SATURDAY WITH LOWER POPS BEYOND THAT.
WILL KEEP HIGHS MAINLY IN THE 60S THROUGH THE PERIOD WITH
EXPECTATION THAT UPPER LOW REMAINS TO THE NORTHWEST OF REGION.
SHOULD A TRACK FURTHER SOUTH INTO THE OHIO VALLEY COME TO
FRUITION...TEMPS WOULD NEED TO BE LOWERED AND POPS RAISED.
&&
AVIATION /DISCUSSION FOR 300600Z TAF ISSUANCE/...
ISSUED AT 1218 AM EDT TUE APR 30 2013
VFR THROUGH THE PERIOD WITH THE POSSIBLE EXCEPTION OF KBMG WHERE A
PERIOD OF MVFR FOG EARLY THIS MORNING STILL POSSIBLE.
HIGH PRESSURE ALONG THE EAST COAST AND AN LOW PRESSURE MOVING INTO
THE CENTRAL PLAINS WILL KEEP A MODERATE SOUTHERLY FLOW ACROSS OUR
REGION. SCATTERED THUNDERSTORMS MAY TRACK ACROSS NORTHERN ILLINOIS
INTO THE SOUTHERN GREAT LAKES OVERNIGHT AND SOME HIGH CLOUDINESS
FROM THIS MAY SPREAD INTO OUR NORTHERN AREAS.
HAVE BACKED OFF A LITTLE MORE ON THE FOG POTENTIAL AS THERE IS STILL
A PRETTY GOOD PRESSURE GRADIENT AND DEWPOINTS DEPRESSIONS ARE STILL
RUNNING 6 DEGREES OR MORE. THE WIND AT KBMG MAY BE LESS...SO WILL
CONTINUE A TEMPO 4 MILES THERE.
OTHERWISE...LOOK FOR SCATTERED CU TO BE THE RULE WITH BROKEN TO
SCATTERED HIGH CLOUDS ON TUESDAY AND BECOMING MOSTLY CLEAR
TUESDAY NIGHT.
SOUTH WINDS WILL BE 8 KNOTS OR LESS THROUGH EARLY MORNING AND THEN
UP TO 12 KNOTS TUESDAY BEFORE DIMINISHING TUESDAY EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...CP
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1228 AM CDT TUE APR 30 2013
.SHORT TERM.../TONIGHT /...
ISSUED AT 338 PM CDT MON APR 29 2013
MAIN CONCERN FOR THE OVERNIGHT PERIOD WILL BE THE TIMING AND
LOCATION OF ANY CONVECTION. INSTABILITY HAS BEEN ON THE INCREASE
THIS AFTERNOON WITH SBCAPES OF 1000 TO 2000 J/KG ACROSS MUCH OF THE
CWA...AND EVEN HIGHER VALUES AROUND THE MISSOURI BORDER. THE 850 TO
700 MB CAP LOOKS TO WEAKEN AFTER THE 23-00Z TIME FRAME AS A 925MB
MOISTURE PLUME OVER KANSAS AND MISSOURI WORKS NORTHWARD. EXPECTING
CONVECTIVE INITIATION IN THE VICINITY OF THE ASSOCIATED THETA-E
CONVERGENCE ZONE IN SOUTHWEST IOWA OR SOUTHEAST NEBRASKA...WITH THE
CONVECTION TRACKING EAST AND NORTH DURING THE OVERNIGHT. THIRTY TO
FORTY KNOTS OF 0-6 KM SHEAR AND A 40 TO 60 KT LLJ BUILDING IN FROM
THE SOUTHWEST AFTER 03Z WILL AID IN INTENSIFYING AND MAINTAINING ANY
STORMS THAT DO FORM THIS EVENING. BOTH ELEVATED AND SURFACE BASED
CONVECTION IS POSSIBLE WITH THE MAIN THREAT FROM THESE STORMS BEING
LARGE HAIL AND DAMAGING WIND GUSTS.
MANY HIGH RESOLUTION MODELS HAVE BEEN TRENDING THE CONVECTION
SLIGHTLY NORTH AND WEST TODAY. THIS HAS ALSO BEEN REFLECTED IN THE
UPDATED SPC CONVECTIVE DAY 1 SLIGHT RISK OUTLOOKS. IN
GENERAL...LEANED TOWARDS A COMBINATION OF THE EAST NMM AND ARW WRF
CORES AND THE 16Z HRRR FOR PLACEMENT OF THE HIGHEST POPS AND QPF
AMOUNTS. HEAVY RAINFALL IS POSSIBLE WITH SOME OF THESE STORMS OVER
CENTRAL IOWA WITH PWATS EXCEEDING ONE INCH AND LOW LEVEL MIXING
RATIOS AROUND 13 G/KG.
STATIONARY SURFACE BOUNDARY OVER WEST CENTRAL AND NORTH CENTRAL IOWA
WASHED OUT EARLY THIS AFTERNOON...ALLOWING WINDS TO VEER SOUTHWARD
AND TEMPERATURES TO RISE BACK INTO THE 70S. THESE SOUTHERLY WINDS
WILL INCREASE OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS IN RESPONSE
TO AN APPROACHING NORTHERN PLAINS COLD FRONT. COMBINED WITH DEW POINTS IN
THE UPPER 50S TO NEAR 60...EXPECT OVERNIGHT LOWS TO ONLY FALL OFF
INTO THE LOW 60S.
.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 338 PM CDT MON APR 29 2013
I EXPECT SOME ONGOING CONVECTION MAINLY ACROSS THE EAST IN THE
MORNING WITH A LULL LATE MORNING. ANOTHER COLD FRONT WILL STRETCH
ACROSS CENTRAL IOWA DURING THE DAY ON TUESDAY AND MAKE SLOW ESE
PROGRESS. FORECAST SOUNDINGS SHOW A PRETTY STOUT CAP IN PLACE BUT
IT QUICKLY ERODES DURING THE MID TO LATE AFTERNOON AND INTO THE
EVENING AND THIS IS WHEN I EXPECT THUNDERSTORMS TO BREAK OUT...AHEAD
OF THE BOUNDARY. LOOKING AT SHEAR...THERE IS SOME THAT EXISTS ALONG
THE BOUNDARY BUT THE BEST SHEAR IS FOUND BEHIND THE BOUNDARY. SOME
STORMS COULD PRODUCE LARGE HAIL AND DAMAGING WIND. DURING TUESDAY
EVENING ADDITIONAL STORMS COULD DEVELOP BEHIND THE FRONT AS WELL
WHERE THE BETTER SHEAR WILL EXIST AND THERE WILL STILL BE SOME
INSTABILITY.
ON WEDNESDAY THE UPPER TROUGH OUT TO THE WEST WILL DIG SOUTH ON THE
LEE SIDE OF THE ROCKIES CREATING QUITE THE TEMPERATURE GRADIENT
ACROSS IOWA. ACROSS THE NORTHWEST HALF TO TWO THIRDS OF THE STATE
HIGHS WILL ONLY BE IN THE 40S AND 50S WHILE ACROSS THE SOUTHEAST
TEMPERATURES WILL BE IN THE 60S TO 70S. THIS TROUGH WILL CONTINUE
TO DIG AS IT PLOWS EAST THROUGH THURSDAY. FORECAST SOUNDINGS ON
THURSDAY SHOW FALLING TEMPERATURES THROUGHOUT THE AFTERNOON HOURS.
IN FACT IT LOOKS LIKE HIGHS WILL LIKELY BE REACHED IN THE MORNING
AND THOSE READINGS WILL ONLY BE IN THE 40S. PRETTY DECENT MOISTURE
TRANSPORT WILL TAKE PLACE DURING THIS TIME AND PRECIPITATION WILL
YIELD SOME PRETTY HIGH QPF VALUES THROUGH THE REMAINDER OF THE
WEEK. FORECAST SOUNDINGS SHOW THAT WE WILL BE COLD ENOUGH FOR AT
MINIMUM A RAIN/SNOW MIX DURING THE DAY ON THURSDAY. IF YOU BELIEVE
THE NAM WE WILL BE COLD ENOUGH FOR ALL SNOW. I HAD A HARD TIME
BUYING INTO THAT SOLUTION COMPLETELY BECAUSE FOR THE PAST FEW DAYS
THE NAM HAD BEEN OVERDOING THE MOISTURE AND THE COOLING. THIS WILL
CERTAINLY BEAR WATCHING BUT I WOULD NOT BE SURPRISED TO SEE SNOW
THURSDAY AFTERNOON AND THURSDAY NIGHT.
BEYOND THIS PERIOD...THE MODELS CONTINUE TO POORLY HANDLE THE
EVOLUTION OF THE CLOSED LOW THAT DEVELOPS OUT OF THE TROUGH. THE
EURO LIFTS THIS CLOSED LOW INTO IOWA OVER THE WEEKEND THEN INTO THE
GREAT LAKES ON MONDAY WHILE THE GFS AND GEM TAKE THE LOW TO THE
SOUTH ACROSS THE SOUTHERN PLAINS. THIS SOLUTION WOULD DRAW DOWN
MUCH COLDER AIR ACROSS THE STATE FOR THE WEEKEND. I TRIED TO LEAN
COOLER BUT BY SUNDAY FORECAST SOUNDINGS SUPPORT HIGHS IN THE 50S. AT
THIS POINT I KEPT 40S NW TO 50S SE ON SATURDAY BUT WE COULD INDEED
SEE TEMPS SOME 5 TO 8 DEGREES COOLER THAT WHAT I HAVE GOING. WE
WILL NEED TO SEE HOW THAT CLOSED LOW EVOLVES AND SHIFTS ACROSS THE
AREA. BEFORE THAT HAPPENS THERE IS JUST TOO MUCH MODEL UNCERTAINTY
TO STATE A PREFERENCE.
&&
.AVIATION...30/06Z
ISSUED AT 1224 AM CDT TUE APR 30 2013
BAND OF SHOWERS AND THUNDERSTORMS WILL PUSH NE ACROSS THROUGH 12Z
AFFECTING NORTHERN SITES KFOD/KALO/KMCW. CEILINGS MAY DROP AT TIMES
TO MVFR IN THUNDERSTORMS AND WINDS WILL BE GUSTY. BEHIND STORMS
WINDS WILL BE FROM THE SOUTH AND CEILINGS WILL BE VFR. WINDS WILL
INCREASE IN THE DAY TUESDAY WITH APPROACHING FRONTAL BOUNDARY. MAY
SEE ADDITIONAL THUNDERSTORMS LATE IN AFTERNOON...BUT DO NOT HAVE
ENOUGH CONFIDENCE IN COVERAGE TO INCLUDE MENTION AT SITES ATTM.
BEHIND BOUNDARY WINDS WILL SHIFT TO THE NORTH LATE IN THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 338 PM CDT MON APR 29 2013
HE MODERATE TO HEAVY RAINFALL EVENT FORECAST IN THE LONG TERM
PERIOD OF THE FORECAST MAY RESULT IN SIGNIFICANT WITHIN-BANK RISES
ALONG MANY STREAMS AND RIVERS. FLOODING IS ALSO
POSSIBLE...ESPECIALLY ALONG THE SMALLER STREAMS AND IN AREAS THAT
RECEIVE HEAVIER RAINFALL. AT THIS TIME IT IS DIFFICULT TO PINPOINT
SPECIFIC STREAMS OR RIVERS GIVEN THE UNCERTAINTY IN THE RAINFALL
FORECAST. THE FORECAST WILL HAVE TO BE MONITORED FOR POTENTIAL
IMPACTS ON AREA RIVERS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...AWB
HYDROLOGY...ZOGG
AREA FORECAST DISCUSSION
NWS TOPEKA KS
327 PM CDT TUE APR 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE APR 30 2013
20Z WATER VAPOR IMAGERY SHOWS BROAD CYCLONIC FLOW ACROSS THE
WESTERN TWO THIRDS OF THE COUNTY WITH ONE SHORTWAVE LIFTING NORTH
INTO CANADA AND A SECOND SHORTWAVE DIGGING INTO NORTHERN UT. AT
THE SURFACE...A FRONTAL BOUNDARY HAS REMAINED STATIONARY FROM
SOUTHWESTERN KS INTO SOUTHEASTERN NEB...CROSSING CLOUD AND
REPUBLIC COUNTIES. LOW LEVEL MOIST CONVERGENCE ALONG THIS FRONT
HAS ALLOWED A STRATOCU FIELD TO DEVELOP ALONG THE FRONT.
FOR THIS EVENING...MODELS SHOW LITTLE IF ANY LARGE SCALE FORCING FOR
CONVECTION. SO IF THUNDERSTORMS ARE GOING TO DEVELOP...IT WILL
LIKELY BE DUE TO PERSISTENT CONVERGENCE ALONG THE FRONT ALONG WITH
DAYTIME HEATING WEAKENING THE CAPPING INVERSION. 19Z LAPS ANALYSIS
SUGGESTS THERE REMAINS SOME INHIBITION TO A SURFACE PARCEL...BUT CIN
IS ONLY AROUND 20 J/KG NEAR THE NEB STATE LINE. HIGH RES MODELS HAVE
BEEN FAIRLY CONSISTENT IN DEPICTING CONVECTION FORMING ALONG THE
FRONT BETWEEN 23Z AND 01Z. WHILE DEEP LAYER SHEAR VECTORS IN THE
WARM SECTOR OR RATHER WEAK FOR SUPERCELL STORMS...THERE IS ENOUGH
CAPE THAT STORMS COULD PRODUCE FROM LARGE HAIL OR STRONG WIND GUSTS.
SO WITH THE FRONT EXPECTED TO REMAIN FAIRLY STATIONARY...POPS ARE
CONFINED TO THE NORTHERN COUNTIES. BY LATE TONIGHT AND THROUGH THE
DAY WEDNESDAY AS THE SHORTWAVE OVER THE INTERMOUNTAIN WEST MOVES
CLOSER TO THE PLAINS...COLD AIR ADVECTION INCREASES AND BEGINS TO
PUSH THE FRONT SOUTH INTO CENTRAL AND EVENTUALLY EASTERN KS. MODELS
SHOW DECENT MID LEVEL FRONTOGENESIS WITH THE FRONT AND SATURATED MID
LEVELS WITH MOST OF THE PRECIP OCCURRING POST FRONTAL. WITH THIS IN
MIND HAVE POPS INCREASING LATE TONIGHT AND INTO WEDNESDAY MORNING
WITH CATEGORICAL WORDING. THINK THIS WILL BE MAINLY SHOWERS WITH
SOME EMBEDDED THUNDERSTORMS NEAR THE FRONT. OTHERWISE MID LEVEL
LAPSE RATES REALLY SHALLOW UP BEHIND THE FRONT. MOST AREAS SHOULD
SEE FALLING TEMPS THROUGH THE DAY AS THE FRONT PASSES. LOWS TONIGHT
WILL BE MILD ACROSS MUCH OF THE AREA WITH LOWER 60S EXPECTED. AREAS
ACROSS NORTH CENTRAL KS SHOULD SEE LOWS IN THE 50S WITH THE FRONT
LIKELY SLIPPING SOUTH BEFORE SUNRISE. ACROSS EASTERN KS...HIGHS WILL
HAVE A CHANCE TO WARM INTO THE 70S BEFORE THE FRONT MOVES THROUGH.
THINK TEMPS IN NORTH CENTRAL KS WILL BE NEARLY STEADY OR SLOWING
FALLING THROUGH THE DAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE APR 30 2013
FOR THE LATE WEEK PERIODS...CHANGES TO THE PREVIOUS FORECAST ARE NOT
VERY LARGE. THIS ISNT DUE TO HIGH CONFIDENCE...BUT RATHER LOW
CONFIDENCE. MODEL GUIDANCE CONTINUES TO SHOW A WIDE RANGE OF
SOLUTIONS...THOUGH THERE SEEMS TO BE A SLOWER AND SOUTHWARD TREND TO
THE UPPER LOW. THE 0Z ECMWF IS NOW THE FASTER/FARTHER NORTH OUTLIER
WITH THE SYSTEM AND THE 12Z NAM NOT FAR BEHIND. THE LAST FEW GFS
RUNS AND EVERY 12Z GFS ENSEMBLE MEMBER ARE ON THE SOUTH/SLOW END. IF
THIS TREND HOLDS...AND WITH THIS BLOCKING REGIME AND TRACK RECORD
ITS VERY HARD TO SAY IT WILL...THE IMPACTS ON SENSIBLE WEATHER WOULD
BE A SLOWER TRANSITION TO FROZEN PRECIPITATION BUT PROLONGED
PRECIPITATION CHANCES. DID SLOW DOWN THE TRANSITION A BIT...WITH A
COMPLETE CHANGE TO SNOW/SLEET ONLY CONFIDENTLY FORECAST FOR THE
NORTHWEST AND THIS BEING FOR AROUND 12 HOURS AS WARMER AIR STILL MAY
COME IN BY THURSDAY AFTERNOON. IN ADDITION...VERY WARM GROUND TEMPS
AND LOW LAYER TEMPS ON THE WARM SIDE SUGGEST ACCUMULATIONS WILL BE
DIFFICULT ESPECIALLY ON ROADWAYS...AND BACKED DOWN AMOUNTS. LAPSE
RATES WOULD STILL SUGGEST THUNDER POSSIBLE FOR THE SOUTH AND EAST
WEDNESDAY NIGHT...AN NOT LIKELY FAR ENOUGH NORTHWEST FOR A
CONVECTIVE SNOW SITUATION...BUT THE DETAILS WILL NEED TO BE WATCHED
AS THIS PERIOD NEARS. PERSISTENT PRECIP AND THE COLD AIR SHOULD KEEP
DIURNAL RISES RATHER LOW FOR THURSDAY...AND RECORD COOL HIGH VALUES
FOR THE DAY IF NOT THE ENTIRE MONTH OF MAY COULD BE SET. COLDEST
TEMPS STILL SHOULD BE THURSDAY NIGHT...WITH NEAR FREEZING LEVELS
LIKELY. THOUGH NOT COMPLETELY CONFIDENT...WILL KEEP FRIDAY PRECIP
ALL LIQUID. FINALLY...AS WITH WEDNESDAY...WIND SPEEDS WEDNESDAY
NIGHT COULD NEAR ADVISORY LEVELS...AND IF THEY CAN OCCUR WITH
FALLING SNOW...A WINTER WEATHER HAZARD COULD PRESENT ITSELF VIA LOW
VISIBILITIES.
FOR THE WEEKEND...WILL KEEP MODERATE PRECIP CHANCES GOING...
EMPHASIZING THE NORTHEAST AHEAD OF THE MORE LIKELY LOCATION OF THE
UPPER LOW...WITH CHANCES DIMINISHING WITH TIME. MODIFICATION SHOULD
TAKE HOLD BY EARLY NEXT WEEK WITH RETURN FLOW BRING MODEST
PRECIPITATION CHANCES BACK BY MONDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM CDT TUE APR 30 2013
WITH A SHORTWAVE DIGGING SOUTHEAST INTO THE FOUR CORNERS
REGION...MODELS PROG THE BOUNDARY TO REMAIN NEARLY STATIONARY TO
THE NORTH OF THE TERMINALS. SINCE THERE IS LITTLE FORCING...
CONVERGENCE ALONG THE BOUNDARY WILL BE KEY IN THUNDERSTORM
DEVELOPMENT AND HAVE LEFT ANY MENTION OF TS OUT OF THE TAFS FOR
NOW. MAIN UNCERTAINTY IS WITH TIMING TO FROPA WEDNESDAY. WITH MOST
GUIDANCE INDICATING PRECIP WILL BE MAINLY POST FRONTAL WITH AT
LEAST MVFR CIGS...TIMING THE FRONT WILL BE KEY IN BRINGING LOWER
FLIGHT CONDITIONS INTO THE TERMINALS. HAVE LEANED CLOSER TO THE
HIGHER RES SOLUTIONS OF THE NAM AND AN EXTRAPOLATED RAP FOR THE
FROPA. THIS WOULD BRING THE FRONT THROUGH MHK AROUND 15Z AND
THROUGH TOP/FOE JUST AFTER 18Z WED.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...65
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1230 PM CDT TUE APR 30 2013
.UPDATE...
ISSUED AT 1230 PM CDT TUE APR 30 2013
STRONG MIXING OF THE BOUNDARY LAYER AND GOOD INSOLATION HAVE
ALLOWED TEMPS TO WARM UP A LITTLE QUICKER WITHIN THE KS RIVER
VALLEY. BECAUSE OF THIS HAVE BUMPED UP AFTERNOON HIGHS FROM THE
ABILENE AREA EAST ALONG THE RIVER. STRATOCU FILED HAS DEVELOPED ON
THE WARM SIDE OF THE STATIONARY FRONT. LAPS AND RAP ANALYSIS STILL
SHOW QUITE A BIT OF INHIBITION TO OVERCOME. SO WITH NO DYNAMIC
FORCING TO TRIGGER CONVECTION...WILL NEED TO WAIT UNTIL LATE
AFTERNOON WHEN HEATING HAS LOWERED THE INHIBITION TO ITS MINIMUM
AND SEE IF CONVERGENCE ALONG THE BOUNDARY IS ENOUGH TO FIRE SOME
STORMS. THE LAST FEW HRRR RUNS HAVE BEEN CONSISTENT IN DEVELOPING
CONVECTION NEAR REPUBLIC COUNTY AROUND 00Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT TUE APR 30 2013
THIS MORNING A SHORTWAVE TROUGH WAS MOVING ACROSS THE NORTHERN
PLAINS AND SOUTHERN CANADA. AS THIS FEATURE MOVES EAST NORTHEAST
INTO ONTARIO SUNSET COUNTRY THIS EVENING. THIS WILL PUSH A FRONTAL
BOUNDARY SOUTHEAST TODAY WITH THE FRONT EXPECTED TO EXTEND FROM
NORTHERN IOWA INTO NORTHWEST KANSAS BY 00Z TUESDAY. A STRONG CAP IS
FORECAST AHEAD OF THE BOUNDARY ACROSS NORTH CENTRAL AND NORTHEAST
KANSAS THROUGH LATE AFTERNOON BEFORE ERODING BY 00Z WEDNESDAY. GOOD
CONVERGENCE IS FORECAST ALONG THE BOUNDARY AND 0-6 KM SHEAR OF 40 TO
50 KTS. SURFACED BASED CAPE OF 1500 TO 2000 J/KG IS FORECAST ALONG
AND AHEAD OF THE FRONT. GIVEN THE SHEAR...STEEP LAPSE
RATES...INSTABILITY...CONVERGENCE AND MOISTURE STRONG TO A FEW
SEVERE THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON AND TONIGHT.
MAIN HAZARDS LOOK TO BE HAIL AND WIND. ANOTHER WARM DAY IS EXPECTED
TODAY AS HIGHS WARM BACK INTO THE LOW TO MID 80S.
THE COLD FRONT WILL BE VERY SLOW MOVING TONIGHT AND REACHING ROUGHLY
A SENECA TO ABILENE LINE BY WEDNESDAY MORNING. AS THE LOW LEVEL JET
INCREASES TONIGHT THERE WILL BE GOOD MOISTURE TRANSPORT INTO THE
FRONTAL ZONE...THUS EXPECT THUNDERSTORMS TO REGENERATE ACROSS NORTH
CENTRAL KANSAS LATER TONIGHT. HAVE INCREASED POPS THERE WHERE THE
BEST MOISTURE FLUX CONVERGENCE IS FORECAST. LOWS TONIGHT WILL
CONTINUE TO BE MILD IN THE 60S WITH TEMPS FALLING INTO THE 40S
BEHIND THE FRONT.
53
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 352 AM CDT TUE APR 30 2013
A DIFFICULT AND NON-CLIMATOLOGICAL FORECAST FOR PORTIONS OF THE MID
AND LONG TERM FORECAST. WILL TRY TO BREAK IT DOWN BY TIME PERIOD AND
ADDRESS VARYING CONFIDENCE LEVELS WITHIN.
OVERALL SYNOPSIS - A DEEP LONG WAVE TROUGH WILL SLOWLY MOVE OVER THE
PLAINS STATES WEDNESDAY AND THURSDAY. AS THIS HAPPENS...A PIECE OF
SHORT WAVE ENERGY WILL DIVE DOWN THE WEST SIDE OF THE MAIN TROUGH
AND INTENSIFY IN THE BASE OF THE LONG WAVE...RESULTING IN A CLOSED
UPPER LOW IN THE CENTRAL PLAINS BY THURSDAY NIGHT. THE STRONG
MERIDIONAL FLOW PATTERN WILL PULL VERY COLD AIR SOUTH INTO MUCH OF
THE GREAT PLAINS...WITH WINTER PRECIPITATION BECOMING A FORECAST
CONCERN. MODEL SOLUTIONS THEN DIVERGE GREATLY BEYOND FRIDAY WITH ONE
MODEL CAMP ALLOWING THE CLOSED LOW TO MOVE NORTHEAST AND BECOME
RE-ABSORBED INTO THE NORTHERN STREAM. THE OTHER CAMP OF MODEL
GUIDANCE KEEPS THE CLOSED LOW ISOLATED AND MEANDERING FROM THE LOWER
MISSOURI RIVER VALLEY INTO THE SOUTHEAST CONUS. WPC...THE MAJORITY
OF GFS ENSEMBLE MEMBERS...AND ECMWF RUNS PRIOR TO THE 00Z RUN TODAY
SUPPORT MAINTAINING THE CLOSED SYSTEM OVER THE PLAINS FOR A LONGER
PERIOD...ALTHOUGH CONFIDENCE IS WELL BELOW AVERAGE.
WEDNESDAY - THE INCOMING TROUGH AND COLD AIR PUSH WILL SEND THE COLD
FRONT SURGING THROUGH THE FORECAST AREA DURING THE DAY ON WEDNESDAY.
TEMPERATURES WILL VARY GREATLY DURING THE DAY...WITH SOME AREAS
SEEING THEIR HIGH DURING THE MORNING HOURS. AMPLE FORCING WITH THE
SYSTEM WILL BRING WIDESPREAD PRECIPITATION TO THE AREA FROM
NORTHWEST TO SOUTHEAST DURING THE DAY. IT IS WORTH NOTING THAT EAST
CENTRAL PARTS OF THE STATE MAY STAY DRY UNTIL VERY LATE IN THE DAY.
THERE WILL BE INSTABILITY PRESENT THROUGHOUT THE DAY...EVEN POST
FRONTALLY...AND EXPECT EMBEDDED THUNDERSTORMS WITHIN THE RAIN. FAR
SOUTHEASTERN PARTS OF THE FORECAST AREA MAY SUSTAIN SURFACE BASED
THUNDERSTORMS PRIOR TO THE FRONTAL PASSAGE DURING THE LATE AFTERNOON
HOURS. IF THE FRONT IS SLOW ENOUGH...A FEW STRONG STORMS WOULD BE
POSSIBLE AHEAD OF IT. OVERALL CONFIDENCE IN EVOLUTION OF WEDNESDAYS
WEATHER IS FAIRLY STRONG.
WEDNESDAY NIGHT AND THURSDAY NIGHT - COLDER AIR WILL CONTINUE TO
ADVECT INTO THE FORECAST AREA THROUGH WEDNESDAY NIGHT. THE COLDER
AIR WILL OVER RUN THE ONGOING PRECIPITATION AS MID AND UPPER LEVEL
FORCING CONTINUES TO BRING ROUNDS OF MODERATE PRECIPITATION THROUGH
THE FORECAST AREA. MODEL FORECAST TEMPERATURE PROFILES SUGGEST THAT
RAIN WILL CHANGE OVER TO SLEET...AND EVENTUALLY SNOW ACROSS MOST IF
NOT ALL OF THE FORECAST AREA BY THURSDAY MORNING. WHILE CLIMATOLOGY
INDICATES THAT THIS IS QUITE RARE...MODEL AGREEMENT IS VERY GOOD AND
THUS FORECAST CONFIDENCE IN PERIODS OF WINTER PRECIPITATION IS
MODERATE TO STRONG...PARTICULARLY WEST AND NORTH OF MANHATTAN. WITH
THIS FORECAST...HAVE INDICATED THAT AS MUCH AS 1 TO 3 INCHES OF
SNOW/SLEET APPEARS POSSIBLE IN NORTH CENTRAL KANSAS WITH LESSER
AMOUNTS TO THE SOUTHEAST. HOWEVER...MUST SAY THAT ANY SNOW
ACCUMULATION WILL BE HIGHLY DEPENDENT UPON THE RATE OF SNOWFALL
GIVEN THE WARM GROUND CONDITIONS...AND THUS THE CONFIDENCE IN ACTUAL
SNOWFALL AMOUNTS IS QUITE LOW. PRECIP TYPE MAY FLUCTUATE THROUGH THE
DAY ON THURSDAY AS WELL OWING TO THE HIGH SUN ANGLE AND POTENTIAL
WARMING OF CLOUD LAYERS...ALONG WITH MORE SUNLIGHT AND HEAT GETTING
THROUGH THE CLOUDS THAN DURING EARLIER MONTHS. THURSDAY NIGHT ALSO
HAS LESS CONFIDENCE IN PRECIP TYPE GIVEN THAT THERE ARE INDICATIONS
OF MINOR WARM ADVECTION...PERHAPS ENOUGH TO CHANGE TO RAIN...AS THE
HEART OF THE TROUGH DRIFTS EAST. SURFACE TEMPERATURES MAY APPROACH
FREEZING BY FRIDAY MORNING.
FRIDAY THROUGH MONDAY - AS PREVIOUSLY MENTIONED...FORECAST
CONFIDENCE GOES WAY DOWN THROUGH THIS PERIOD AS MODEL GUIDANCE IS
STRONGLY DIVERGENT REGARDING EVOLUTION OF THE CLOSED LOW. AT THIS
TIME...DID NOT CHANGE THE PREVIOUS FORECAST MUCH...AND LEANED
SOMEWHAT CLOSELY TO THE 00Z GFS WHICH KEEPS THE UPPER LOW AND
PERIODS OF SHOWERS CLOSELY ASSOCIATED WITH THE FORECAST AREA THROUGH
SUNDAY. HOWEVER...IF A SOLUTION CLOSER TO THE 00Z ECMWF WOULD
VERIFY...DRY AIR WOULD BUILD INTO THE AREA WITH NO PRECIPITATION AND
WARMER TEMPERATURES THROUGH THIS TIME FRAME.
BARJENBRUCH
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM CDT TUE APR 30 2013
WITH A SHORTWAVE DIGGING SOUTHEAST INTO THE FOUR CORNERS
REGION...MODELS PROG THE BOUNDARY TO REMAIN NEARLY STATIONARY TO
THE NORTH OF THE TERMINALS. SINCE THERE IS LITTLE FORCING...
CONVERGENCE ALONG THE BOUNDARY WILL BE KEY IN THUNDERSTORM
DEVELOPMENT AND HAVE LEFT ANY MENTION OF TS OUT OF THE TAFS FOR
NOW. MAIN UNCERTAINTY IS WITH TIMING TO FROPA WEDNESDAY. WITH MOST
GUIDANCE INDICATING PRECIP WILL BE MAINLY POST FRONTAL WITH AT
LEAST MVFR CIGS...TIMING THE FRONT WILL BE KEY IN BRINGING LOWER
FLIGHT CONDITIONS INTO THE TERMINALS. HAVE LEANED CLOSER TO THE
HIGHER RES SOLUTIONS OF THE NAM AND AN EXTRAPOLATED RAP FOR THE
FROPA. THIS WOULD BRING THE FRONT THROUGH MHK AROUND 15Z AND
THROUGH TOP/FOE JUST AFTER 18Z WED.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...WOLTERS
SHORT TERM...53
LONG TERM...BARJENBRUCH
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
921 PM EDT WED MAY 1 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH SATURDAY.&&
.NEAR TERM /THROUGH THURSDAY/...
UPDATE 2115L: MAINLY CLR SKIES ACROSS THE FA ATTM W/ JUST A FEW
PATCHY MID CLDS ACROSS THE N... WATCHING SOME STRATUS ACROSS ERN
NB ATTM WHICH IS PUSHING WSWWRD AND LAST FEW NGTS HAS SPREAD WWRD
INTO CENTRAL NB BEFORE PULLING BACK TO THE E DURING THE AM HRS.
LATEST HRRR SEEMS TO HAVE A GOOD HANDLE ON THIS AND BRINGS A
NARROW FINGER OF THIS INTO SWRN NB BY LATE TNGT/ERLY THU BUT KEEPS
IT OUT OF OUR AREA. NO CHANGES NEEDED ATTM...
UPDATE 1915L: HRLY TEMPS WELL ABV THE HRLY CURVE SO HAVE ADJUSTED
ACCORDINGLY. ALSO...BASED ON CURRENT TRENDS APPEARS FCST LOWS MAY
BE TOO COOL SO HAVE BUMPED UP BY A FEW DEGREES...
RIDGING BOTH SFC AND ALOFT WILL BE THE DOMINANT FEATURE ACROSS
NORTHERN NEW ENGLAND DURING THE NEAR TERM (AND BEYOND). A STRONG
UPPER RIDGE ACROSS THE OHIO VALLEY WILL CONTINUE TO SLOWLY BUILD
TO THE NORTH AND EAST THROUGH THURSDAY. AN UPPER LOW ACROSS THE
MARITIMES WILL PASS EAST OF NOVA SCOTIA THU AND JUST BRUSH THE
AREA WITH A SLIGHTLY COOLER AIR MASS. A DISTURBANCE SPILLING OVER
THE TOP OF THE RIDGE WILL CAUSE SOME CLOUDS TO MOVE ACROSS THE
WESTERN MOUNTAINS LATE TONIGHT THROUGH EARLY THU AFTERNOON WITH
THE SLIGHT CHANCE OF A SHOWER THURSDAY. THE GFS IS THE MOST
AGGRESSIVE WITH THIS FEATURE AND THE OTHER MODELS ARE DRIER.
LOWERED THE POPS JUST A BIT IN GOOD COORDINATION WITH KGYX ACROSS
THE WESTERN ZONES AS THE GFS LOOKS A BIT OVERDONE...BUT DID NOT
DISCOUNT THE LOW POPS THAT THE MID SHIFT PAINTED IN THE FAR WEST
TOMORROW. HIGH TEMPS WERE RAISED A BIT TOMORROW ACROSS THE WESTERN
ZONES AS THE COOLER AIR MASS WILL BRUSH THE EASTERN ZONES EARLY
ENOUGH IN THE DAY TO HAVE SOME IMPACT ON THE HIGHS...BUT PROBABLY
NOT SO MUCH IN THE WEST.&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL REMAIN ENTRENCHED
ACROSS THE NORTHEASTERN CONUS, KEEPING THE WEATHER DRY AND MILD
THROUGH THE END OF THE WEEK. FRIDAY WILL BE A BIT COOLER THAN WHAT
WE`VE SEEN FOR THE FIRST PART OF THE WEEK, BUT HIGHS WILL STILL BE
WELL ABOVE NORMAL. NOTED THAT THE 12Z GFS HAS COME INTO BETTER
AGREEMENT WITH THE NAM AND ECMWF, BACKING OFF ON PRECIP CHANCES AND
SKY COVER ON SATURDAY. THEREFORE, HAVE DROPPED THE SLIGHT CHANCE
POPS FOR NORTHERN MAINE ON SATURDAY AND GONE MOSTLY TO PARTLY SUNNY
FOR SKY COVER. LESS CLOUDS MEANS MORE SUN, SO HAVE ALSO BUMPED
TEMPERATURES UP INTO THE MID AND UPPER 60S. WITH CLEAR SKIES, LIGHT
WINDS AND LOW DEWPOINTS, OVERNIGHT TEMPERATURES WILL BE COOL WITH
MOST SPOTS DROPPING INTO THE MID AND UPPER 30S. THE USUAL COLD
LOCATIONS WILL BOTTOM OUT AROUND 30.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE REGION WILL CONTINUE TO BE DOMINATED BY THE RIDGE THAT HAS
MADE FOR EXCELLENT WEATHER CONDITIONS OVER THE PAST WEEK. THERE
ARE SOME DIFFERENCES IN THE GUIDANCE IN HOW THE RIDGE ACROSS THE
REGION AND UPPER LEVEL LOW ACROSS THE SOUTHEAST PLAYS OUT OVER THE
LONG TERM. LATE SUNDAY INTO SUNDAY NIGHT THE 06Z GFS DOES WANT TO
HINT AT LIGHT QPF ACROSS NORTHERN MAINE ALTHOUGH ALL OTHER
GUIDANCE IS LEANING TOWARD A DRY WEATHER. THE LATEST 12Z GFS
INDICATES LESS QPF THAN 06 GFS. THE HPC ALSO LEANED MORE TOWARD
DRIER CONDITIONS. IT DOES LOOK LIKE THERE COULD BE SOME CLOUD
COVER ACROSS THE NORTH. THIS SHOULD CLEAR OUT EARLY MONDAY AND
THEN MORE CLOUDS COULD FORM MAINLY ACROSS THE NORTH THROUGH THE
DAY MONDAY. THERE IS MODEL DIVERGENCE AS WE GET LATE IN THE PERIOD
WITH 06Z/12Z GFS HOLDING ONTO THE CLOSED UPPER LOW ACROSS THE
SOUTHERN US AND EVENTUALLY SWINGING THE LOW NORTHEAST. THE ECMWF
SEEMS TO KEEP THE UPPER HIGH STRONG AND LOOSES THE CLOSED UPPER
LOW. RIGHT NOW WILL KEEP CONTINUITY WITH PREVIOUS FORECAST WITH
LOW CONFIDENCE IN THE DAY 7 ON. ALTHOUGH WITH LOW CONFIDENCE BOTH
THE ECMWF AND GFS INDICATE THE STRONG UPPER LEVEL HIGH EVENTUALLY
BREAKING DOWN THE END OF NEXT WEEK. DECIDED TO LOAD WITH GMOS AND
ADJUST TOWARD FORECAST/ECMWF TO GAIN CONTINUITY WITH PREVIOUS
FORECAST AND HPC.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR THROUGH TOMORROW.
SHORT TERM: VFR CONDITIONS AND DRY WEATHER WILL PREVAIL THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK.
&&
.MARINE...
NEAR TERM: NO ISSUES OVER THE NEXT 24 HOURS. A SEA BREEZE ALONG THE
SHORELINE WILL DISSIPATE BY SUNSET. A NORTHEAST WIND WILL FRESHEN
UP A BIT TO AROUND 15 KT ACROSS THE COASTAL WATERS TOMORROW. SEAS
GENERALLY 3 FEET OR LESS THROUGH TOMORROW.
SHORT TERM: HIGH PRESSURE WILL KEEP WINDS AND WAVES BELOW SCA
LEVELS THROUGH THE END OF THE WEEK.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...KHW/CB
SHORT TERM...HASTINGS
LONG TERM...JORDAN
AVIATION...KHW
MARINE...KHW/CB/HASTINGS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
432 PM EDT TUE APR 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT TUE APR 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE IN THIS SW FLOW ALOFT WAS
LIFTING NORTH INTO NW ONTARIO. AT THE SFC...LOW PRES WAS LOCATED
OVER NW ONTARIO WITH A COLD FRONT EXTENDING SOUTH INTO FAR WRN LAKE
SUPERIOR AND NW WI. A WARM FRONT WAS DRAPED ACROSS NCNTRL AND NE WI.
BULGE OF WARM DRY AIR AT AROUND 850 MB AS NOTED ON 12Z GRB SNDG AND
LATEST RAPID RUC SNDGS AT KIMT HAS PRODUCED SEVERAL HUNDRED J/KG OF
CIN....KEEPING ATMOSPHERE CAPPED ENOUGH TO PROHIBIT SHOWERS FROM
FORMING OVER MUCH OF THE FCST AREA SO FAR THIS AFTERNOON. JUST IN
LATEST RADAR VOLUME SCAN STARTING TO SEE A FEW SHOWERS POPPING OVER
HOUGHTON COUNTY BUT WITH ONLY AROUND 200-300 J/KG OF MLCAPE NOT
REALLY EXPECTED MUCH IN WAY OF THUNDER.
AS MODELS SHOW FRONT MOVG SLOWLY EAST INTO CENTRAL FCST AREA...RAP
RUC SNDGS FOR KIMT SUGGESTS CAP ALOFT MAY ERODE JUST ENOUGH TO ALLOW
FOR SOME ISOLD TO SCT SHRA/TSRA TO FORM TOWARD SUNSET OVER CNTRL
FCST AREA. INCREASING 800-700 MB FGEN IN RESPONSE TO RIGHT ENTRANCE
REGION FORCING IN 140+ KT 3H JET OVER NRN PLAINS AND WRN ONTARIO
WILL BE MAIN DRIVING FORCE FOR BAND OF RAIN WHICH MODELS PROJECT TO
FORM LATE THIS EVENING AND EARLY OVERNIGHT OVER CENTRAL PORTION OF
THE FCST AREA. THIS BAND OF PCPN IS THEN PROGGED BY MODELS TO SHIFT
OVER THE WRN CWA LATE TONIGHT INTO WED AS BEST FGEN FORCING SHIFTS
WEST. LOWS TONIGHT WILL BE IN THE 40S UNDER MOSTLY CLOUDY SKIES.
MODEL AVG QPF INDICATES THAT PORTIONS OF GOGEBIC AND ONTONAGON
COUNTIES COULD SEE UP TO QUARTER INCH OF PCPN LATE TONIGHT INTO
WEDNESDAY. COLDER AIR (8H TEMPS DROPPING BLO 0C )SEEPING INTO THE
WRN CWA COULD CAUSE SOME SNOW TO MIX IN WITH RAIN BY LATE WED
AFTERNOON AS TEMPS FALL INTO THE MID TO UPPER 30S TOWARD EVENING.
N-NW ONSHORE FLOW OFF COOL LAKE SUPERIOR ALONG CLOUDY SKIES WILL
RESULT IN MAX TEMPS ON THE LOWER END OF MODEL GUIDANCE FOR WEDNESDAY
WITH HIGHS RANGING FROM THE LOWER TO MID 40S ALONG LAKE SUPERIOR TO
GENERALLY THE LOWER TO MID 50S EAST AND SCNTRL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 432 PM EDT TUE APR 30 2013
FORECAST CONTINUES TO DEAL WITH THE UPPER TROUGH DEVELOPING IN THE
IN THE NORTHERN PLAINS AND WHAT HAPPENS TO IT AS IT CUTS OFF AROUND
THE END OF THIS WEEK AND DRIFTS THIS WEEKEND.
TO START THE PERIOD...THE FORECAST CONCERN IS THE STALLED 850MB
FRONT STRETCHING FROM NORTHERN LAKE SUPERIOR THROUGH SOUTHEAST
MINNESOTA AND INTO THE CENTRAL PLAINS AS THE UPPER TROUGH SLOWLY
SHIFTS EAST THROUGH THE NORTHERN PLAINS. THE POSITION OF THE FRONT
WILL BE THE MAIN CONCERN...AS THERE WILL LIKELY BE AN AXIS OF HIGHER
PRECIPITATION AMOUNTS ALONG THIS FRONT. LATEST TRENDS IN THE MODELS
IS THAT THE 850MB FRONT IS A LITTLE FARTHER WEST AND THE HEAVIEST
PRECIPITATION LOOKS TO FALL SOMEWHERE EAST OF DULUTH AND WEST OF A
LINE FROM BARAGA TO WATERSMEET. WITH THE AREA THE 850-700MB WAA/FGEN
IS LINING UP...WOULD THINK THAT THE BEST PRECIPITATION WOULD BE OVER
THE FAR WESTERN CWA...BUT STILL EXPECT LIGHTER VALUES OVER THE REST
OF THE WESTERN CWA. THIS MATCHES UP WELL WITH THE 09Z SREF QPF
PROBABILITIES. THERE WILL PROBABLY BE SOME SHOWERS OVER THE
CENTRAL U.P. BUT THE AMOUNTS SHOULD BE LIGHTER THAN SEEN OVER THE
WEST. UNFORTUNATELY...THIS PRECIPITATION WON/T HELP THE ALREADY
SWOLLEN RIVERS AND STREAMS OVER FAR WESTERN UPPER MICHIGAN AND WILL
HEIGHTEN THE AFFECTS IN THE HWO AND INDIVIDUAL RIVER PRODUCTS.
BASED OFF THE THERMAL FIELDS AND BUFKIT SOUNDINGS...IT APPEARS THAT
IT WILL MAINLY BE SNOW OVER THE FAR WESTERN CWA...WITH A RAIN/SNOW
MIX OVER THE WEST-CENTRAL...BEFORE CHANGING TO ALL RAIN EAST OF A
LINE FROM NEGAUNEE TO CRYSTAL FALLS. THERE STILL REMAINS SOME
UNCERTAINTY IN THE P-TYPE TYPE AS THEY HAVE BEEN VARYING IN HOW FAR
WEST THE WARM AIR ALOFT SLIDES. NAM AND OUR REGIONAL WRF-ARW DO HINT
AT A SOME DRYING ALOFT WHICH COULD LIMIT ICE CRYSTAL POTENTIAL OVER
THE WEST...WHICH WILL BE SOMETHING TO WATCH. IF THE PRECIP STAYS AS
SNOW OVER THE WEST HALF OF GOGEBIC AND WESTERN ONTONAGON
COUNTY...THEY COULD SEE SIGNIFICANT LATE SEASON
SNOWFALL...ESPECIALLY ON THE COLDER SURFACES AND HIGHER TERRAIN.
CURRENTLY HAVE BORDERLINE WARNING SNOW AMOUNTS FOR WEDNESDAY NIGHT
INTO THURSDAY MORNING...SO WILL CONTINUE TO MENTION IN THE HWO. IF
CONFIDENCE WAS A LITTLE GREATER ON EXACT LOCATION OF THE HEAVIEST
QPF...AND THERE WEREN/T SEVERAL OTHER FLOOD WARNING/WATCH/ADVISORY
PRODUCTS OUT FOR GOGEBIC COUNTY...COULD HAVE ISSUED A WINTER
STORM WATCH.
THE UPPER TROUGH STARTS THE CUTOFF PROCESS THURSDAY NIGHT INTO
FRIDAY MORNING...WHICH WILL ALLOW THE FLOW ALOFT TO BECOME MORE
SOUTHEASTERLY AND SHIFT THE FRONT WEST. THIS WILL PULL WARMER AIR
INTO THE AREA AND SHOULD LIMIT THE SNOW POTENTIAL. BUT THIS WARMER
AIR MOVING IN ALOFT WILL LEAD COLD AIR TRAPPED NEAR THE SURFACE.
THIS HAS BEEN HINTED AT OVER THE LAST DAY...BUT HAVE CONCERNS THAT
THE GROUND TEMPERATURES WON/T GO BELOW FREEZING. THUS...WILL JUST
HAVE A SLIGHT CHANCE MENTION FOR AREAS WITH RAIN AND TEMPS BELOW 31
DEGREES. WITH THE DIFFERENCES IN THE HANDLING OF THE TROUGH CUTTING
OFF...THERE ARE DIFFERENCES IN THE MOVEMENT OF THE FRONT...SO WILL
GO WITH A BROADER POPS HEADING INTO FRIDAY...BUT THE BEST FOCUS
OVER THE SOUTHWEST HALF.
THE WEEKEND INTO EARLY NEXT WEEK STILL REMAINS UP IN THE AIR DUE TO
THE DIFFERENCES IN THE LOCATION OF THE UPPER LOW. 00Z ECMWF IS
CONSISTENT WITH IT/S PREVIOUS RUN AND IS FARTHEST TO THE NORTH. 12Z
GFS CONTINUES IT/S TREND OF BEING WELL TO THE SOUTH OF THE AREA
/CENTRAL MISSISSIPPI VALLEY/...WHILE THE 12Z GEM HAS IT IN THE
GREAT LAKES. AS WITH YESTERDAY...WILL FOLLOW A GENERAL CONSENSUS
INTO NEXT WEEK AS THE LOCATION OF THE LOW HAS LARGE IMPLICATIONS ON
TEMPERATURES AND PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 220 PM EDT TUE APR 30 2013
A COLD FRONT WILL CROSS UPPER MICHIGAN THIS AFTERNOON BUT DRY AIR AT
LOW-LEVELS WILL LIKELY PROHIBIT SHOWERS FROM FORMING AT THE TAF
SITES. A DISTURBANCE MOVING ALONG THE FRONT LATE THIS EVENING AND
OVERNIGHT WILL BRING A BETTER CHC FOR SHRA ESPECIALLY AT THE WRN TAF
SITES. WINDS SHIFTING FROM SW TO MORE WESTERLY LATE TONIGHT INTO
WEDNESDAY WILL LIKELY BRING SOME LOWER CIGS ONSHORE AT KIWD AND KCMX
AS CONDITIONS LOWER FM VFR TO IFR OR PERHAPS LIFR. EXPECT GUSTY
SOUTH WINDS AOA 30 KTS AT KSAW THROUGH THIS AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT TUE APR 30 2013
NO GALES SEEN IN THIS FORECAST PERIOD. WINDS WILL GET UP TO 30 KNOTS
ACROSS THE EASTERN PORTION OF LAKE SUPERIOR EARLY THIS EVENING WITH
TIGHTENING GRAD AHEAD OF COLD FRONT. WINDS THEN STAY GEENRALLY AT OR
BELOW 25 KNOTS FOR THE REST OF THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 432 PM EDT TUE APR 30 2013
ANOTHER DAY OF WARM TEMPERATURES HAS CONTINUED THE SNOW MELT AND
THE RISING RIVER LEVELS ACROSS THE AREA. FORTUNATELY...RAINFALL
AMOUNTS OVER THE LAST COUPLE OF DAYS HAVE BEEN FAIRLY LIGHT AND HAS
KEPT THE FLOODING CONCERNS TO THE SNOW MELT. THE MAIN SNOW LEFT
OVER THE AREA IS OVER THE HIGHER TERRAIN LOCATIONS OVER THE
WEST...WHERE VALUES ARE IN THE 3-15 INCH RANGE. THE WARM
TEMPERATURES TONIGHT SHOULD CONTINUE THE MELT...BUT IS SHOULD BE
SLOWED AS TEMPERATURES FALL BEHIND A COLD FRONT THAT MOVES
THROUGH TONIGHT. THIS FRONT WILL PRODUCE ISOLATED/SCATTERED SHOWERS
BUT WIDESPREAD MODERATE-HEAVY RAINFALL AMOUNTS ARE NOT EXPECTED.
ATTENTION THEN TURNS TO AN UPPER LEVEL FRONT THAT STALLS OVER FAR
WESTERN UPPER MICHIGAN WEDNESDAY THROUGH THURSDAY. THIS HAS THE
POTENTIAL TO PRODUCE OVER AN INCH OF QPF OVER THE WESTERN THIRD OF
UPPER MICHIGAN THROUGH THURSDAY NIGHT. THE HEAVIEST
AMOUNTS...POTENTIALLY EXCEEDING 1.5 INCHES WILL BE OVER WESTERN
ONTONAGON AND WESTERN GOGEBIC COUNTIES. WITH THE COLDER
TEMPERATURES...THERE IS UNCERTAINTY IN THE THE EXACT PRECIPITATION
TYPE...BUT IT LOOKS LIKE A RAIN/SNOW MIX OVER THE WEST AND MAINLY
SNOW OVER THE FAR WEST. THIS PRECIPITATION WILL NOT HELP MATTERS
OVER THE WESTERN CWA...WHERE MANY RIVERS/STREAMS/CREEKS ARE
EXCEEDING BANKFULL OR FLOODING. THIS PRECIPITATION WILL DEFINITELY
NEED TO BE WATCHED OVER THE NEXT DAY OR TWO TO PIN DOWN AMOUNTS AND
TYPES...WHICH WILL HELP DETERMINE THE TIME THEY WILL INFLUENCE THE
RIVERS. ELSEWHERE...THE TIME LAGGED FLOW INCREASES FROM THE SNOW
MELT WILL LEAD TO CONTINUED RISES OVER THE NORTH CENTRAL
TRIBUTARIES OF THE ESCANABA AND MICHIGAMME RIVERS. THESE AREAS MAY
SEE FLOODING OVER THE COMING DAYS.
IN THE NEAR TERM...THE GREATEST FLOODING THREAT IS FOR THE RIVERS
IN WEST AND CENTRAL UPPER MICHIGAN. SEVERAL RIVER FLOOD
WARNING/WATCH/ADVISORIES ARE ALREADY IN PLACE...ALONG WITH SOME
AERIAL FLOOD ADVISORIES. FOR COMPLETE DETAILS...SEE THE LATEST RIVER
FLOOD WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLASH FLOOD WATCH UNTIL 10 PM CDT THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
221 PM EDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND. AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.
RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013
NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.
THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 220 PM EDT TUE APR 30 2013
A COLD FRONT WILL CROSS UPPER MICHIGAN THIS AFTERNOON BUT DRY AIR AT
LOW-LEVELS WILL LIKELY PROHIBIT SHOWERS FROM FORMING AT THE TAF
SITES. A DISTURBANCE MOVING ALONG THE FRONT LATE THIS EVENING AND
OVERNIGHT WILL BRING A BETTER CHC FOR SHRA ESPECIALLY AT THE WRN TAF
SITES. WINDS SHIFTING FROM SW TO MORE WESTERLY LATE TONIGHT INTO
WEDNESDAY WILL LIKELY BRING SOME LOWER CIGS ONSHORE AT KIWD AND KCMX
AS CONDITIONS LOWER FM VFR TO IFR OR PERHAPS LIFR. EXPECT GUSTY
SOUTH WINDS AOA 30 KTS AT KSAW THROUGH THIS AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013
NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&
.HYDROLOGY...
ISSUED AT 543 AM EDT TUE APR 30 2013
UNSEASONABLY WARM AIR AND HIGHER DEWPOINTS WILL CONTINUE TO FAVOR
RAPID MELTING OF THE REMAINING SNOWPACK ACROSS NORTH CENTRAL AND
WEST UPPER MICHIGAN KEEPING RIVER LEVELS HIGH. A COLD FRONT MOVING
THROUGH THIS AFTERNOON INTO TONIGHT MAY PRODUCE ADDITIONAL RAINFALL
OF A QUARTER TO HALF INCH IN SOME LOCATIONS. MUCH COOLER CONDITIONS
EXPECTED FOR REST OF WEEK COMBINED WITH LIMITED SNOWFALL SHOULD LEAD
TO A SLOW FALL IN RIVER LEVELS. ADDITIONAL CHANCES OF RAIN AND
EVEN SNOW OVER THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY NIGHT...WITH THE HEAVIEST PRECIPITATION OVER THE WESTERN
THIRD OF UPPER MICHIGAN. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE BLACK RIVER
NEAR BESSEMER...THE TRAP ROCK RIVER...THE STURGEON RIVER OF
BARAGA/HOUGHTON COUNTIES...THE PESHEKEE RIVER...THE PAINT RIVER NEAR
CRYSTAL FALLS...THE ONTONAGON RIVER AT EWEN...THE CHOCOLAY RIVER
NEAR HARVEY...AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL LEAD TO SIGNIFICANT UNCERTAINTY WITH
THE RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS WHERE
MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS. AT
OTHER LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED
TO MORE ACCURATELY ASSESS THE MELT RATES FOR THE RIVER MODELS.
AN NWS SURVEY OF THE PESHEKEE RIVER MONDAY MORNING REVEALED THICK
ICE COVERING MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4
RIVER GAUGING LOCATION/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE
BEING TAKEN USING A WIREWEIGHT GAUGE AT THE LOCATION/ AND THICK ICE
COVER ON MOST OF LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A
FEW ICE JAMS WERE NOTED MONDAY MORNING WHICH COULD CAUSE SOME
PROBLEMS OVER THE NEXT COUPLE OF DAYS AS THE RIVER RISES.
MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT
OF AREAL FLOODING WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. AREAL TYPE FLOODING HAS BEEN REPORTED...THE MOST WIDESPREAD
OVER GOGEBIC COUNTY WHERE AN AREAL FLOOD WARNING WAS ISSUED THROUGH
TUESDAY EVENING. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD
WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLASH FLOOD WATCH UNTIL 10 PM CDT THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...07
AVIATION...VOSS
MARINE...07
HYDROLOGY...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
113 PM EDT TUE APR 30 2013
.AVIATION...
//DISCUSSION...
CONVECTION CONTINUES TO DIE OUT AS IT TRACKS THROUGH SOUTHEAST
MICHIGAN EARLY THIS AFTERNOON. CURRENT RADAR TRENDS SUPPORT
CONTINUING SHOWERS OVER THE TAF SITES FOR ANOTHER HOUR AS DRIER MORE
STABLE AIR MOVES IN FROM THE WEST...ENDING MUCH OF THE SHOWERS OVER
THE TAF SITES DURING THE LATE AFTERNOON. THIS WARM STABLE AIRMASS IS
EXPECTED TO REMAIN IN PLACE TONIGHT AND WEDNESDAY...WITH DRY WEATHER
EXPECTED FOR THE REST OF THE TAF PERIOD. ALTHOUGH WINDS ARE EXPECTED
TO BECOME LIGHT OVERNIGHT...WARM AIR ADVECTION AND LINGERING HIGH
CLOUDS ARE EXPECTED TO MITIGATE FOG DEVELOPMENT DURING THE OVERNIGHT
HOURS...HOWEVER A SHORT PERIOD OF MVFR FOG CANNOT BE RULED OUT
TOWARDS SUNRISE. THIS THREAT IS NOT HIGH ENOUGH TO INCLUDE IN THIS
SET OF TAFS.
FOR DTW...THE THREAT FOR THUNDERSTORMS IS BASICALLY OVER AT
DTW...HOWEVER ANOTHER HOUR OF SHOWERS IS POSSIBLE BEFORE THE RAIN
MOVES OFF TO THE EAST. ALTHOUGH THERE IS A POSSIBILITY OF MVFR FOG
EARLY WEDNESDAY MORNING...THE LACK OF SIGNIFICANT RAINS OVER THE
AIRPORT SHOULD KEEP THE THREAT FOR FOG DEVELOPMENT LOW AT THIS TIME.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CIGS ABOVE 5000 FEET THROUGH 19Z...HIGH
CONFIDENCE IN CIGS ABOVE 5000 FEET AFTER 19Z.
&&
.PREV DISCUSSION...ISSUED 1029 AM EDT TUE APR 30 2013
UPDATE...
NWP MODELS CONTINUE TO HAVE ABSOLUTELY NO CLUE WITH REGARDS TO THE
ONGOING PRECIPITATION OVER THE WESTERN CWA. THESE MODELS ARE
COMPLETELY DRY...EVEN WITH THE 12Z CYCLE...WHICH AS RADAR AND
METAR REPORTS SHOW COULD NOT BE FURTHER FROM THE TRUTH. THE ONLY
MODEL THAT HAS ANY IDEA WHAT IS HAPPENING WITH THIS THETA-E DRIVEN
CONVECTION IS THE LOCAL HRRR MODEL WHICH PUSHES THESE RAIN SHOWERS
THROUGH THE CWA DURING THE EARLY AFTERNOON HOURS. THEREFORE WILL
RAISE POPS SIGNIFICANTLY INTO THE CATEGORICAL RANGE AS THIS
ACTIVITY SWEEPS THROUGH THE CWA THIS AFTERNOON.
WITH THIS ACTIVITY AND ABUNDANT CLOUD COVER HIGH TEMPERATURES WILL
SURELY NOT GET CLOSE TO 80 AS PREVIOUSLY ADVERTISED. WHILE THERE
IS STILL HOPE THE LATE APRIL SUN ANGLE WILL BE ABLE TO BOOST
TEMPERATURES BEHIND THESE SHOWERS...WILL TAKE A GOOD 5 TO 10 DEGREES
OFF PREVIOUS HIGH TEMPERATURES AS A FIRST SLICE AT HIGH
TEMPERATURES THIS AFTERNOON.
PREV DISCUSSION...ISSUED 359 AM EDT TUE APR 30 2013
SHORT TERM... TODAY AND TONIGHT
A WARM FRONT WILL MOVE FROM THE MIDWEST THROUGH LOWER MICHIGAN TODAY
AS LOW PRESSURE MOVES FROM THE NORTHERN PLAINS INTO NORTHERN
ONTARIO. THE FRONT WILL FIRST PRESENT CLOUDS, A CHANCE OF SHOWERS,
AND POSSIBLY A THUNDERSTORM DURING THE MORNING BEFORE PASSING NORTH
AND OPENING THE DOOR ON WARM TEMPERATURES DURING THE AFTERNOON
THROUGH TONIGHT.
EARLY MORNING SURFACE ANALYSIS INDICATES THE WARM FRONT IS SOMEWHAT
DIFFUSE BUT MODEL ANALYSIS FIELDS INDICATE A WELL DEFINED THETA-E
AXIS IN THE 850 TO 700 MB LAYER FEATURING 850 MB DEWPOINT AROUND 10C
THAT MATCHES UP WELL WITH UPSTREAM 00Z SOUNDINGS. THERE IS ALSO A
SHARP LEADING MOISTURE GRADIENT WHICH IS PROJECTED THROUGH LOWER
MICHIGAN DURING THE MORNING. THE ASSOCIATED SYSTEM RELATIVE
ISENTROPIC ASCENT AND MOISTURE ADVECTION IS EXPECTED TO BE A
DESTABILIZING PROCESS OVER OUR AREA THROUGH THE REST OF THE MORNING.
SPC MESOANALYSIS INDICATES MID LEVEL LAPSE RATES OF 7-8C/KM
AVAILABLE FROM UPSTREAM CENTERED OVER EASTERN IOWA WHICH WILL TEND
TO SPREAD OVER LOWER MICHIGAN BY ABOUT SUNRISE. IT IS THEN
REASONABLE TO EXPECT DEVELOPMENT OF CHANCE/SCATTERED COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER THE ENTIRE AREA AS A STARTING POINT
WITH AN UPDATE TO GREATER COVERAGE AS RADAR TRENDS DICTATE
REFINEMENT ON LOCATION.
THE PASSAGE OF THE WARM FRONT BY EARLY AFTERNOON WILL THEN BRING THE
WARM SECTOR OF THE LARGER SCALE PATTERN OVER OUR AREA. MODEL
SOUNDINGS INDICATE THE MIXED LAYER WILL REMAIN RELATIVELY SHALLOW,
ONLY UP TO ABOUT 875 MB, IN SUPPORT OF MAX TEMPS IN THE MID TO UPPER
70S MOST LOCATIONS. MODEL SURFACE STREAMLINES ORIGINATE MORE FROM
THE OHIO VALLEY THROUGH THE DAY SO AN INTERIOR MAX OF 80 WILL BE AT
THE TOP OF THE RANGE. MORE IMPORTANT IS THE SLIGHT ONSHORE WIND
COMPONENT THAT WILL KEEP READINGS COOLER NEAR THE LAKE HURON
SHORELINE AND LAKE ST CLAIR/ERIE AGGREGATE. THIS SAME TENDENCY IN
THE WIND WILL THEN BACK EVEN MORE TOWARD THE SOUTHEAST WITH SOME
DECOUPLING TONIGHT. THIS WILL ALLOW MIN TEMPS TO SETTLE DOWN INTO
THE 50S WITH DRY CONDITIONS AND PARTLY CLOUD SKY THROUGH SUNRISE
WEDNESDAY.
LONG TERM...WEDNESDAY THROUGH MONDAY.
WEDNESDAY...A DIGGING TROUGH INTO COLORADO AND ANTICYCLONICALLY
CURVED JET STREAK EJECTING NORTHWARD THROUGH CANADA WILL FORCE
AGGRESSIVE DOWNSTREAM AMPLIFICATION OF THE EASTERN NOAM UPPER LEVEL
RIDGE. 500MB VORTICITY FIELD IS SUGGESTIVE THAT DEEP COLUMN
SUBSIDENCE WILL BE IN PLACE OVER THE CENTRAL GREAT LAKES...WITH A
SHARP EASTERN GRADIENT TO THE PRECIPITATION OVER PORTIONS OF
WISCONSIN/IOWA. CLOSED HEIGHT CONTOURS AT 500MB ARE SHOWN TO SNEAK
INTO SOUTHEASTERN MICHIGAN WEDNESDAY AFTERNOON. THE GOOD CONNECTION
OF REMNANT ELEVATED MIXED LAYER WILL STILL EXIST FOR WEDNESDAY
AFTERNOON...SUPPORTING THE WARMEST TEMPERATURES OF THIS STRETCH. LOW
80 APPEARS A GOOD FORECAST FOR THE TRI CITIES WITH MID TO UPPER 70S
ELSEWHERE.
THE ANTICYCLONIC INFLECTION/BUBBLE IN JET IS EXPECTED TO WORK
THROUGH THE REGION LATE WEDNESDAY NIGHT AND THURSDAY. THIS FEATURE
SHOULD SUPPORT AN ADDITIONAL SHORTWAVE RIDGE COMPONENT. NCEP MODELS
ARE VERY SUSPECT WITH QPF SNEAKING ONTO THE WESTERN FRINGES OF THE
CWA...PRIMARILY IN THE LEE OF LAKE MICHIGAN. PRECIPITATION SHOULD
REMAIN IN THE COLD SECTOR...BUT BREAKS OUT CONVECTION IN A SECONDARY
ZONE WELL AHEAD OF MAIN STATIONARY BAROCLINIC ZONE. THE PROBLEM IS
THIS DOESN/T HAVE THE LOOK OF A WEATHER SYSTEM THAT WOULD FORCE
PREFRONTAL TROUGH CONVECTION. THE BELIEF IS THERE ARE LIKELY SURFACE
MOISTURE PARAMETRIZATION ISSUES WHICH IS SOME CAUSE TO THE NOISY
SOLUTIONS. THE FORECAST IS ALREADY SIDING IN A DRY FASHION...AND DID
NOT SEE ANYTHING IN THE NEW NWP TO SUGGEST OTHERWISE.
UNFORTUNATELY...THIS IS A BINARY ALL OR NOTHING TYPE FORECAST WITH A
CONSIDERABLE AMOUNT OF BUST POTENTIAL IF PRECIPITATION MOVES IN. THE
AIRMASS IN PLACE WILL HAVE UNDERGONE SOME HOMOGENIZATION BY
THURSDAY. THEREFORE...HIGHS ARE GENERALLY 3 TO 4 DEGREES COOLER THAN
THE PRECEDING DAY.
MODELS THEN DIVERGE CONSIDERABLY FOR THIS WEEKEND. THE FAVORED ECMWF
SHOWS A CONSIDERABLE CUTOFF EVENT OVER THE CENTRAL PART OF THE
COUNTRY BY FRIDAY. THE UPSTREAM RESPONSE IS TO FORM A POSITIVE
HEIGHT ANOMALY COUPLET TO THE NORTHEAST OF THE CLOSED LOW. THE ECMWF
SUGGESTS THE CENTER OF THE ANOMALY WILL MEANDER...BUT SHOULD
MAINTAIN A FIRM GRASP OF LOWER MICHIGAN THROUGH SATURDAY. THE
FORECAST IS SIDED THERE...AND WILL GO DRY THROUGH THE FIRST HALF OF
THE WEEKEND. DO NOT FEEL PARTICULARLY GOOD ABOUT THE MAX T FORECAST
THIS WEEKEND AS THERE IS PLENTY OF COLD/PRECIPITATION/CLIMO BIASED
SOLUTIONS FACTORING IN THE OFFERED GUIDANCE. WILL GIVE IT SOME TIME
BEFORE GETTING MORE AGGRESSIVE WITH THE WEEKEND TEMPERATURES.
MARINE...
LOW PRESSURE MOVING FROM NORTHERN MINNESOTA INTO NORTHERN ONTARIO
TODAY WILL BOOST SOUTHERLY WIND OVER THE OPEN WATERS OF LAKE HURON,
BUT WARM AIR MOVING OVER THE COLD WATER WILL PROVIDE VERY HIGH
STABILITY. THIS WILL KEEP WAVE ACTION SUBDUED THROUGH TONIGHT. AFTER
THAT, THE TRAILING COLD FRONT WILL SETTLE CLOSE ENOUGH TO THE
STRAITS FOR LIGHTER WIND OVER ALL MARINE AREAS. FAVORABLE MARINE
CONDITIONS ARE THEN ANTICIPATED THROUGH THE REST OF THE WEEK AS THE
FRONT IS PROJECTED TO STALL OVER THE WESTERN GREAT LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1029 AM EDT TUE APR 30 2013
.UPDATE...
NWP MODELS CONTINUE TO HAVE ABSOLUTELY NO CLUE WITH REGARDS TO THE
ONGOING PRECIPITATION OVER THE WESTERN CWA. THESE MODELS ARE
COMPLETELY DRY...EVEN WITH THE 12Z CYCLE...WHICH AS RADAR AND
METAR REPORTS SHOW COULD NOT BE FURTHER FROM THE TRUTH. THE ONLY
MODEL THAT HAS ANY IDEA WHAT IS HAPPENING WITH THIS THETA-E DRIVEN
CONVECTION IS THE LOCAL HRRR MODEL WHICH PUSHES THESE RAIN SHOWERS
THROUGH THE CWA DURING THE EARLY AFTERNOON HOURS. THEREFORE WILL
RAISE POPS SIGNIFICANTLY INTO THE CATEGORICAL RANGE AS THIS
ACTIVITY SWEEPS THROUGH THE CWA THIS AFTERNOON.
WITH THIS ACTIVITY AND ABUNDANT CLOUD COVER HIGH TEMPERATURES WILL
SURELY NOT GET CLOSE TO 80 AS PREVIOUSLY ADVERTISED. WHILE THERE
IS STILL HOPE THE LATE APRIL SUN ANGLE WILL BE ABLE TO BOOST
TEMPERATURES BEHIND THESE SHOWERS...WILL TAKE A GOOD 5 TO 10 DEGREES
OFF PREVIOUS HIGH TEMPERATURES AS A FIRST SLICE AT HIGH
TEMPERATURES THIS AFTERNOON.
&&
.AVIATION...ISSUED 723 AM EDT TUE APR 30 2013
//DISCUSSION...
CONVECTION HAS FLARED UP VIGOROUSLY ALONG THE LEADING EDGE OF THE
MID LEVEL MOISTURE AXIS ASSOCIATED WITH A WARM FRONT THAT WILL MOVE
THROUGH LOWER MICHIGAN TODAY. EARLIER TERMINAL UPDATES REFLECT THE
INCREASED COVERAGE AND INTENSITY OF THE STORMS WITH A SHORT PERIOD
OF MVFR/IFR CONDITIONS AND PERHAPS A SOUTHWEST WIND GUST AS THE MAIN
CLUSTER MOVES THROUGH THE REGION. EXPECT THE STORMS TO BE NORTH AND
EAST OF THE TERMINAL SITES BY ABOUT NOON FOLLOWED BY WARM SECTOR
CHARACTER OF VFR CONDITIONS WITH GUSTY SOUTH WIND UNTIL SUNSET.
AVIATION CONDITIONS WILL REMAIN FAVORABLE TONIGHT WITH LIGHT WIND
BUT LIKELY NOT ENOUGH TO AVOID A SHORT PERIOD OF MVFR FOG AROUND
SUNRISE WEDNESDAY MORNING.
FOR DTW... THERE IS SOME POTENTIAL FOR THE SOUTH END OF CONVECTIVE
LINE TO BECOME MORE SOLID AS STORMS APPROACH DTW BUT THE
WIDTH/DURATION WILL REMAIN RELATIVELY SHORT. ALL STORM ACTIVITY WILL
BE EAST OF THE AIRPORT BY NOON OR SHORTLY AFTER.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN THUNDERSTORM COVERAGE AND TIMING DURING THE
MORNING.
&&
.PREV DISCUSSION...ISSUED 359 AM EDT TUE APR 30 2013
SHORT TERM... TODAY AND TONIGHT
A WARM FRONT WILL MOVE FROM THE MIDWEST THROUGH LOWER MICHIGAN TODAY
AS LOW PRESSURE MOVES FROM THE NORTHERN PLAINS INTO NORTHERN
ONTARIO. THE FRONT WILL FIRST PRESENT CLOUDS, A CHANCE OF SHOWERS,
AND POSSIBLY A THUNDERSTORM DURING THE MORNING BEFORE PASSING NORTH
AND OPENING THE DOOR ON WARM TEMPERATURES DURING THE AFTERNOON
THROUGH TONIGHT.
EARLY MORNING SURFACE ANALYSIS INDICATES THE WARM FRONT IS SOMEWHAT
DIFFUSE BUT MODEL ANALYSIS FIELDS INDICATE A WELL DEFINED THETA-E
AXIS IN THE 850 TO 700 MB LAYER FEATURING 850 MB DEWPOINT AROUND 10C
THAT MATCHES UP WELL WITH UPSTREAM 00Z SOUNDINGS. THERE IS ALSO A
SHARP LEADING MOISTURE GRADIENT WHICH IS PROJECTED THROUGH LOWER
MICHIGAN DURING THE MORNING. THE ASSOCIATED SYSTEM RELATIVE
ISENTROPIC ASCENT AND MOISTURE ADVECTION IS EXPECTED TO BE A
DESTABILIZING PROCESS OVER OUR AREA THROUGH THE REST OF THE MORNING.
SPC MESOANALYSIS INDICATES MID LEVEL LAPSE RATES OF 7-8C/KM
AVAILABLE FROM UPSTREAM CENTERED OVER EASTERN IOWA WHICH WILL TEND
TO SPREAD OVER LOWER MICHIGAN BY ABOUT SUNRISE. IT IS THEN
REASONABLE TO EXPECT DEVELOPMENT OF CHANCE/SCATTERED COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER THE ENTIRE AREA AS A STARTING POINT
WITH AN UPDATE TO GREATER COVERAGE AS RADAR TRENDS DICTATE
REFINEMENT ON LOCATION.
THE PASSAGE OF THE WARM FRONT BY EARLY AFTERNOON WILL THEN BRING THE
WARM SECTOR OF THE LARGER SCALE PATTERN OVER OUR AREA. MODEL
SOUNDINGS INDICATE THE MIXED LAYER WILL REMAIN RELATIVELY SHALLOW,
ONLY UP TO ABOUT 875 MB, IN SUPPORT OF MAX TEMPS IN THE MID TO UPPER
70S MOST LOCATIONS. MODEL SURFACE STREAMLINES ORIGINATE MORE FROM
THE OHIO VALLEY THROUGH THE DAY SO AN INTERIOR MAX OF 80 WILL BE AT
THE TOP OF THE RANGE. MORE IMPORTANT IS THE SLIGHT ONSHORE WIND
COMPONENT THAT WILL KEEP READINGS COOLER NEAR THE LAKE HURON
SHORELINE AND LAKE ST CLAIR/ERIE AGGREGATE. THIS SAME TENDENCY IN
THE WIND WILL THEN BACK EVEN MORE TOWARD THE SOUTHEAST WITH SOME
DECOUPLING TONIGHT. THIS WILL ALLOW MIN TEMPS TO SETTLE DOWN INTO
THE 50S WITH DRY CONDITIONS AND PARTLY CLOUD SKY THROUGH SUNRISE
WEDNESDAY.
LONG TERM...WEDNESDAY THROUGH MONDAY.
WEDNESDAY...A DIGGING TROUGH INTO COLORADO AND ANTICYCLONICALLY
CURVED JET STREAK EJECTING NORTHWARD THROUGH CANADA WILL FORCE
AGGRESSIVE DOWNSTREAM AMPLIFICATION OF THE EASTERN NOAM UPPER LEVEL
RIDGE. 500MB VORTICITY FIELD IS SUGGESTIVE THAT DEEP COLUMN
SUBSIDENCE WILL BE IN PLACE OVER THE CENTRAL GREAT LAKES...WITH A
SHARP EASTERN GRADIENT TO THE PRECIPITATION OVER PORTIONS OF
WISCONSIN/IOWA. CLOSED HEIGHT CONTOURS AT 500MB ARE SHOWN TO SNEAK
INTO SOUTHEASTERN MICHIGAN WEDNESDAY AFTERNOON. THE GOOD CONNECTION
OF REMNANT ELEVATED MIXED LAYER WILL STILL EXIST FOR WEDNESDAY
AFTERNOON...SUPPORTING THE WARMEST TEMPERATURES OF THIS STRETCH. LOW
80 APPEARS A GOOD FORECAST FOR THE TRI CITIES WITH MID TO UPPER 70S
ELSEWHERE.
THE ANTICYCLONIC INFLECTION/BUBBLE IN JET IS EXPECTED TO WORK
THROUGH THE REGION LATE WEDNESDAY NIGHT AND THURSDAY. THIS FEATURE
SHOULD SUPPORT AN ADDITIONAL SHORTWAVE RIDGE COMPONENT. NCEP MODELS
ARE VERY SUSPECT WITH QPF SNEAKING ONTO THE WESTERN FRINGES OF THE
CWA...PRIMARILY IN THE LEE OF LAKE MICHIGAN. PRECIPITATION SHOULD
REMAIN IN THE COLD SECTOR...BUT BREAKS OUT CONVECTION IN A SECONDARY
ZONE WELL AHEAD OF MAIN STATIONARY BAROCLINIC ZONE. THE PROBLEM IS
THIS DOESN/T HAVE THE LOOK OF A WEATHER SYSTEM THAT WOULD FORCE
PREFRONTAL TROUGH CONVECTION. THE BELIEF IS THERE ARE LIKELY SURFACE
MOISTURE PARAMETRIZATION ISSUES WHICH IS SOME CAUSE TO THE NOISY
SOLUTIONS. THE FORECAST IS ALREADY SIDING IN A DRY FASHION...AND DID
NOT SEE ANYTHING IN THE NEW NWP TO SUGGEST OTHERWISE.
UNFORTUNATELY...THIS IS A BINARY ALL OR NOTHING TYPE FORECAST WITH A
CONSIDERABLE AMOUNT OF BUST POTENTIAL IF PRECIPITATION MOVES IN. THE
AIRMASS IN PLACE WILL HAVE UNDERGONE SOME HOMOGENIZATION BY
THURSDAY. THEREFORE...HIGHS ARE GENERALLY 3 TO 4 DEGREES COOLER THAN
THE PRECEDING DAY.
MODELS THEN DIVERGE CONSIDERABLY FOR THIS WEEKEND. THE FAVORED ECMWF
SHOWS A CONSIDERABLE CUTOFF EVENT OVER THE CENTRAL PART OF THE
COUNTRY BY FRIDAY. THE UPSTREAM RESPONSE IS TO FORM A POSITIVE
HEIGHT ANOMALY COUPLET TO THE NORTHEAST OF THE CLOSED LOW. THE ECMWF
SUGGESTS THE CENTER OF THE ANOMALY WILL MEANDER...BUT SHOULD
MAINTAIN A FIRM GRASP OF LOWER MICHIGAN THROUGH SATURDAY. THE
FORECAST IS SIDED THERE...AND WILL GO DRY THROUGH THE FIRST HALF OF
THE WEEKEND. DO NOT FEEL PARTICULARLY GOOD ABOUT THE MAX T FORECAST
THIS WEEKEND AS THERE IS PLENTY OF COLD/PRECIPITATION/CLIMO BIASED
SOLUTIONS FACTORING IN THE OFFERED GUIDANCE. WILL GIVE IT SOME TIME
BEFORE GETTING MORE AGGRESSIVE WITH THE WEEKEND TEMPERATURES.
MARINE...
LOW PRESSURE MOVING FROM NORTHERN MINNESOTA INTO NORTHERN ONTARIO
TODAY WILL BOOST SOUTHERLY WIND OVER THE OPEN WATERS OF LAKE HURON,
BUT WARM AIR MOVING OVER THE COLD WATER WILL PROVIDE VERY HIGH
STABILITY. THIS WILL KEEP WAVE ACTION SUBDUED THROUGH TONIGHT. AFTER
THAT, THE TRAILING COLD FRONT WILL SETTLE CLOSE ENOUGH TO THE
STRAITS FOR LIGHTER WIND OVER ALL MARINE AREAS. FAVORABLE MARINE
CONDITIONS ARE THEN ANTICIPATED THROUGH THE REST OF THE WEEK AS THE
FRONT IS PROJECTED TO STALL OVER THE WESTERN GREAT LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......KURIMSKI
AVIATION.....BT
SHORT TERM...BT
LONG TERM....CB
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
800 AM EDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND. AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.
RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013
NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.
THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 800 AM EDT TUE APR 30 2013
A COLD FRONT WILL CROSS UPPER MICHIGAN TODAY BRINGING SCATTERED
SHOWERS THIS AFTERNOON OVER THE WEST AND THIS EVENING OVER CENTRAL
UPPER MICHIGAN. ISOLATED THUNDERSTORMS ARE POSSIBLE...ESPECIALLY AT
KSAW...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
OTHERWISE...WITH THE APPROACHING FRONT AND
HEATING/MIXING...SOUTHERLY WINDS ARE EXPECTED TO BE GUSTING TO NEAR
25KTS TOWARDS THE AFTERNOON HOURS BEFORE SHIFTING TO THE WEST. DRIER
AIR WILL MOVE IN BEHIND THE FRONT WITH VFR CONDITIONS EXPECTED BY
LATE EVENING AND OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013
NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&
.HYDROLOGY...
ISSUED AT 543 AM EDT TUE APR 30 2013
UNSEASONABLY WARM AIR AND HIGHER DEWPOINTS WILL CONTINUE TO FAVOR
RAPID MELTING OF THE REMAINING SNOWPACK ACROSS NORTH CENTRAL AND
WEST UPPER MICHIGAN KEEPING RIVER LEVELS HIGH. A COLD FRONT MOVING
THROUGH THIS AFTERNOON INTO TONIGHT MAY PRODUCE ADDITIONAL RAINFALL
OF A QUARTER TO HALF INCH IN SOME LOCATIONS. MUCH COOLER CONDITIONS
EXPECTED FOR REST OF WEEK COMBINED WITH LIMITED SNOWFALL SHOULD LEAD
TO A SLOW FALL IN RIVER LEVELS. ADDITIONAL CHANCES OF RAIN AND
EVEN SNOW OVER THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY NIGHT...WITH THE HEAVIEST PRECIPITATION OVER THE WESTERN
THIRD OF UPPER MICHIGAN. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE BLACK RIVER
NEAR BESSEMER...THE TRAP ROCK RIVER...THE STURGEON RIVER OF
BARAGA/HOUGHTON COUNTIES...THE PESHEKEE RIVER...THE PAINT RIVER NEAR
CRYSTAL FALLS...THE ONTONAGON RIVER AT EWEN...THE CHOCOLAY RIVER
NEAR HARVEY...AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL LEAD TO SIGNIFICANT UNCERTAINTY WITH
THE RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS WHERE
MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS. AT
OTHER LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED
TO MORE ACCURATELY ASSESS THE MELT RATES FOR THE RIVER MODELS.
AN NWS SURVEY OF THE PESHEKEE RIVER MONDAY MORNING REVEALED THICK
ICE COVERING MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4
RIVER GAUGING LOCATION/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE
BEING TAKEN USING A WIREWEIGHT GAUGE AT THE LOCATION/ AND THICK ICE
COVER ON MOST OF LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A
FEW ICE JAMS WERE NOTED MONDAY MORNING WHICH COULD CAUSE SOME
PROBLEMS OVER THE NEXT COUPLE OF DAYS AS THE RIVER RISES.
MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT
OF AREAL FLOODING WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. AREAL TYPE FLOODING HAS BEEN REPORTED...THE MOST WIDESPREAD
OVER GOGEBIC COUNTY WHERE AN AREAL FLOOD WARNING WAS ISSUED THROUGH
TUESDAY EVENING. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD
WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...07
AVIATION...JLB
MARINE...07
HYDROLOGY...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
545 AM EDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND. AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.
RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013
NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.
THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 442 AM EDT TUE APR 30 2013
WITH THE ARRIVAL OF MOIST AIR FOG HAS DEVELOPED AT THE KCMX/KSAW
SITES....AND WITH GENERAL UPSLOPE FLOW IN THESE AREAS EXPECT THE
IFR/LIFR CONDITIONS TO CONTINUE THROUGH THE OVERNIGHT PERIOD.
DOWNSLOPING WINDS WILL LIKELY INHIBIT THE DEVELOPMENT OF ANY
SIGNIFICANT LOWER CEILINGS/VIS AT KIWD TONIGHT. A COLD FRONT WILL
CROSS UPPER MICHIGAN DURING THE DAYTIME TUESDAY...BRINGING SHOWERS
TO EACH OF THE TAF SITES...WITH KIWD/KCMX CLEARING OUT FOR THE LATE
AFTERNOON/EARLY EVENING TIME FRAME FOR A SHORT TIME. ISOLATED
THUNDERSTORMS ARE POSSIBLE TOMORROW...ESPECIALLY AT KSAW...BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
OTHERWISE...WITH THE APPROACHING FRONT AND
HEATING/MIXING...SOUTHERLY WINDS ARE EXPECTED TO BE GUSTING TO NEAR
25KTS TOWARDS THE AFTERNOON HOURS BEFORE SHIFTING TO THE WEST.
LASTLY...LLWS IS STILL POSSIBLE TONIGHT AT THE TAF SITES WITH
STRONGER SOUTHERLY WINDS ALOFT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013
NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&
.HYDROLOGY...
ISSUED AT 543 AM EDT TUE APR 30 2013
UNSEASONABLY WARM AIR AND HIGHER DEWPOINTS WILL CONTINUE TO FAVOR
RAPID MELTING OF THE REMAINING SNOWPACK ACROSS NORTH CENTRAL AND
WEST UPPER MICHIGAN KEEPING RIVER LEVELS HIGH. A COLD FRONT MOVING
THROUGH THIS AFTERNOON INTO TONIGHT MAY PRODUCE ADDITIONAL RAINFALL
OF A QUARTER TO HALF INCH IN SOME LOCATIONS. MUCH COOLER CONDITIONS
EXPECTED FOR REST OF WEEK COMBINED WITH LIMITED SNOWFALL SHOULD LEAD
TO A SLOW FALL IN RIVER LEVELS. ADDITIONAL CHANCES OF RAIN AND
EVEN SNOW OVER THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY NIGHT...WITH THE HEAVIEST PRECIPITATION OVER THE WESTERN
THIRD OF UPPER MICHIGAN. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE BLACK RIVER
NEAR BESSEMER...THE TRAP ROCK RIVER...THE STURGEON RIVER OF
BARAGA/HOUGHTON COUNTIES...THE PESHEKEE RIVER...THE PAINT RIVER NEAR
CRYSTAL FALLS...THE ONTONAGON RIVER AT EWEN...THE CHOCOLAY RIVER
NEAR HARVEY...AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL LEAD TO SIGNIFICANT UNCERTAINTY WITH
THE RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS WHERE
MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS. AT
OTHER LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED
TO MORE ACCURATELY ASSESS THE MELT RATES FOR THE RIVER MODELS.
AN NWS SURVEY OF THE PESHEKEE RIVER MONDAY MORNING REVEALED THICK
ICE COVERING MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4
RIVER GAUGING LOCATION/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE
BEING TAKEN USING A WIREWEIGHT GAUGE AT THE LOCATION/ AND THICK ICE
COVER ON MOST OF LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A
FEW ICE JAMS WERE NOTED MONDAY MORNING WHICH COULD CAUSE SOME
PROBLEMS OVER THE NEXT COUPLE OF DAYS AS THE RIVER RISES.
MAIN STEM RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT
OF AREAL FLOODING WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. AREAL TYPE FLOODING HAS BEEN REPORTED...THE MOST WIDESPREAD
OVER GOGEBIC COUNTY WHERE AN AREAL FLOOD WARNING WAS ISSUED THROUGH
TUESDAY EVENING. FOR COMPLETE DETAILS...SEE THE LATEST RIVER FLOOD
WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...07
AVIATION...MCD
MARINE...07
HYDROLOGY...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM EDT TUE APR 30 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE NW CONUS RESULTING IN SW FLOW FROM THE CNTRL PLAINS TO THE
NRN GREAT LAKES. A VIGOROUS SHORTWAVE TROUGH WAS LCOATED OVER THE SE
CORNER OF SASK INTO FAR NW ND. AT THE SFC...LOW PRES WAS LOCATED
OVER NE SOUTH DAKOTA WITH A WARM FRONT THROUGH SE MN INTO SRN WI. A
LLJ AHEAD OF THE WITH INFLOW OF MOIST/UNSTABLE AIR SUPPORTED TSRA
INTO SRN WI AND CNTRL LAKE MI. ISOLD SHOWERS NEAR ESC-ISQ HAD
DIMINISHED AS THE STRONGER CONVECTION DEVELOPED TO THE SOUTH.
UPSTREAM...A WEAK SHRTWV AHEAD OF THE LOW SUPPORTED A BAND OF
SHRA/TSRA OVER NRN MN.
RADAR AND SATELLITE TRENDS SUGGEST THAT MOST OF THE CONVECTION OVER
WI WILL SLIDE JUST SOUTH OF THE CWA BUT MAY EXPAND JUST ENOUGH FOR
SOME SCT SHRA/TSRA...MAINLY SOUTH OF A LINE FROM IMT-ERY. AS THE SD
LOW LIFTS NORTHEAST THROUGH THROUGH NW MN TO NW ONTARIO...WAA AND
MOISTURE ADVECTION WILL INCREASE WITH THE STRENGTHENING SRLY FLOW.
TEMPS CLIMBING INTO THE LOWER TO MID 70S COMBINED WITH DEWPOINTS IN
THE LOWER TO MID 50S WILL RESULT IN MLCAPE VALUES IN THE 600-1200
J/KG RANGE BY THIS AFTERNOON. THE COLD FRONT DRAPED TO THE SOUTH OF
THE LOW MOVING INTO THE WEST UPPER MI THIS AFTERNOON WILL BE THE
MAIN FOCUS FOR SHRA/TSRA DEVELOPMENT. ALTHOUGH THE STRONGEST QVECTOR
CONV WILL BE WELL NORTH OF THE REGION...EVEN MODEST LOW LEVEL CONV
ALONG AND AHEAD OF THE FRONT SHOULD SUPPORT SCT TSRA THIS AFTERNOON
INTO THIS EVENING. SOME STRONGER STORMS MAY BE POSSIBLE WITH 0-6KM
SHEAR VALUES IN THE 40-50 KT...BUT THE GREATER SVR POTENTIAL IS
EXPECTED FARTHER SOUTH(PER SPC) WHERE INSTABILITY WILL BE GREATER.
THE HIGHEST POPS VALUES WERE INCLUDED OVER THE WEST LATE THIS
AFTERNOON AND INTO THE CNTRL AND EAST THIS EVENING...BEFORE
SHRA/TSRA WEAKEN WITH DIURNAL COOLING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE APR 30 2013
NAM SHOWS A 500 MB RIDGE OVER THE EASTERN U.S. WITH A TROUGH IN THE
NORTHERN AND CENTRAL ROCKIES AND A CLOSED 500 MB LOW OVER THE GULF
COAST 12Z WED. THE TROUGH MOVES INTO THE NORTHERN PLAINS 00Z THU AND
INTO THE UPPER GREAT LAKES ON THU. NAM SHOWING SOME 850-500 MB
Q-VECTOR CONVERGENCE WITH DEEPER MOISTURE OVER THE WEST HALF OF
UPPER MICHIGAN 12Z WED WHICH REMAINS THROUGH 00Z THU. THIS NARROW
RIBBON OF DEEPER MOISTURE REMAINS OVER THE WESTERN CWA THROUGH 12Z
THU BEFORE THIS MOVES AND EXPANDS EASTWARD. GFS AND ECMWF SHOW ABOUT
THE SAME THING AS WELL.
THIS FORECAST PERIOD GETS DOMINATED BY COLDER AIR COMING INTO THE
AREA AND THERE COULD BE A RAIN/SNOW MIX ACROSS THE WESTERN U.P.
STARTING LATE WED NIGHT AND LASTING INTO THU NIGHT. THE WESTERN CWA
ALSO HAS THE BEST MOISTURE AND THEREFORE WILL HAVE THE HIGHEST POPS
WHILE THE EAST IS FURTHER AWAY FROM THE FRONTAL BAND PCPN THAT SETS
UP AND IS IN WARMER AIR AS WELL. QUITE A GRADIENT SETS UP IN
TEMPERATURES WITH THE COLDEST READINGS ACROSS THE WEST AND THE
WARMEST IN THE EAST FOR THROUGH THU. QPF WILL CONTINUE TO BE
HEAVIEST OVER THE WEST WITH ANYWHERE FROM 0.25 INCH ACROSS THE EAST
TO 1.25 IN THE WEST FROM WED TO THU NIGHT. THE COLD AIR DOES NOT
ARRIVE UNTIL LATE WED NIGHT ACROSS THE WEST AND COULD SEE ANYWHERE
FROM 1 TO 6 INCHES WEST OF A LINE FROM BIG BAY TO IRON RIVER FROM
WED NIGHT INTO THU NIGHT. DID RAISE TEMPERATURES A BIT FOR WED WITH
LATER ARRIVAL OF COLDER AIR AND RAISED THEM WED NIGHT AS WELL A
COUPLE DEGREES. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST EXCEPT TO GO A BIT DRIER IN THE EASTERN CWA WHICH IS
FURTHER AWAY FROM THE FRONTAL BAND.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH AND CLOSED LOW
OVER THE CENTRAL PLAINS 12Z FRI WITH A RIDGE OVER THE EASTERN U.S.
PATTERN DOES NOT CHANGE MUCH FOR 12Z SAT WITH THE 500 MB RIDGE
REMAINING STATIONARY. THIS 500 MB LOW CONTINUES TO SPIN ACROSS THE
CENTRAL PLAINS 12Z SUN FOR THE ECMWF AND THE GFS IS MUCH FURTHER
SOUTH WITH THE PLACEMENT OF THE 500 MB LOW. GFS CONTINUES TO MOVE
THE LOW EAST WELL SOUTH OF THE AREA 12Z MON WHILE THE ECMWF TAKES
THE LOW AND ASSOCIATED TROUGH THROUGH THE AREA. MANUAL PROGS KIND OF
WASH THIS SYSTEM OUT WITH TIME WITH WEAK SFC PRESSURE PATTERNS. WITH
SLOW CHANGE IN UPPER PATTERN...PERSISTENCE LOOKS TO BE THE WAY TO GO
FOR THIS FORECAST. TEMPERATURES WILL SLOWLY WARM THIS EXTENDED
FORECAST PERIOD FROM BELOW NORMAL TO NEAR NORMAL AND WILL BE WET
WITH PCPN CHANCES ALMOST EACH PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 442 AM EDT TUE APR 30 2013
WITH THE ARRIVAL OF MOIST AIR FOG HAS DEVELOPED AT THE KCMX/KSAW
SITES....AND WITH GENERAL UPSLOPE FLOW IN THESE AREAS EXPECT THE
IFR/LIFR CONDITIONS TO CONTINUE THROUGH THE OVERNIGHT PERIOD.
DOWNSLOPING WINDS WILL LIKELY INHIBIT THE DEVELOPMENT OF ANY
SIGNIFICANT LOWER CEILINGS/VIS AT KIWD TONIGHT. A COLD FRONT WILL
CROSS UPPER MICHIGAN DURING THE DAYTIME TUESDAY...BRINGING SHOWERS
TO EACH OF THE TAF SITES...WITH KIWD/KCMX CLEARING OUT FOR THE LATE
AFTERNOON/EARLY EVENING TIME FRAME FOR A SHORT TIME. ISOLATED
THUNDERSTORMS ARE POSSIBLE TOMORROW...ESPECIALLY AT KSAW...BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
OTHERWISE...WITH THE APPROACHING FRONT AND
HEATING/MIXING...SOUTHERLY WINDS ARE EXPECTED TO BE GUSTING TO NEAR
25KTS TOWARDS THE AFTERNOON HOURS BEFORE SHIFTING TO THE WEST.
LASTLY...LLWS IS STILL POSSIBLE TONIGHT AT THE TAF SITES WITH
STRONGER SOUTHERLY WINDS ALOFT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 442 AM EDT TUE APR 30 2013
NO GALES SEEN IN THIS FORECAST PERIOD. WINDS DO GET UP TO 30 KNOTS
ACROSS THE EAST AND NORTH CENTRAL TODAY AS A SFC LOW HEADS
NORTHEAST. WINDS THEN STAY BELOW 25 KNOTS FOR THE REST OF THE
PERIOD.
&&
.HYDROLOGY...
ISSUED AT 443 PM EDT MON APR 29 2013
ANOTHER DAY OF WARM TEMPERATURES HAS CONTINUED THE SNOW MELT AND
THE RISING RIVER LEVELS ACROSS THE AREA. FORTUNATELY...RAINFALL
AMOUNTS OVER THE LAST COUPLE OF DAYS HAVE BEEN FAIRLY LIGHT AND HAS
KEPT THE FLOODING CONCERNS TO THE SNOW MELT. WITH 5-20 INCHES OF
SNOW STILL REMAINING OVER WESTERN UPPER MICHIGAN...EXPECT THE WARM
TEMPERATURES TONIGHT AND TUESDAY TO CONTINUE THE SNOWMELT AND KEEP
RIVER LEVELS AT HIGHER LEVELS. A COLD FRONT MOVING THROUGH TUESDAY
AFTERNOON INTO TUESDAY NIGHT MAY PRODUCE ADDITIONAL RISES ON THE
ALREADY SWOLLEN RIVERS ACROSS THE AREA. MUCH COOLER TEMPERATURES
EXPECTED FOR REST OF WEEK BEHIND THE FRONT...WHICH COMBINED WITH
LIMITED SNOWFALL SHOULD LEAD TO A SLOW FALL IN RIVER LEVELS THROUGH
THE REST OF THE WEEK. ADDITIONAL CHANCES OF RAIN AND EVEN SNOW OVER
THE WEST ARE POSSIBLE WEDNESDAY AFTERNOON INTO THURSDAY NIGHT...WITH
THE HEAVIEST PRECIPITATION OVER THE WESTERN THIRD OF UPPER MICHIGAN.
SO...EVEN THOUGH TEMPERATURES WILL BE COOLER THIS MAY BE OFFSET BY
THE ADDITIONAL PRECIPITATION THAT MAY OCCUR.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...THE ONTONAGON
RIVER AT EWEN...THE CHOCOLAY RIVER NEAR HARVEY...AND EVENTUALLY THE
MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. MELTING SCENARIOS
STILL REMAIN THE BIGGEST CONFIDENCE REDUCERS IN RIVER FORECASTS FOR
THE PESHEKEE AND MICHIGAMME BASINS WHERE MOST OF THE MELTING HAS NOT
HIT ANY OBSERVED RIVER POINTS YET. AT OTHER LOCATIONS...SUFFICIENT
RUNOFF FROM MELTING HAS BEEN OBSERVED TO MORE ACCURATELY GET A
HANDLE OF MELT RATES FOR THE RIVER MODELS. NWS SURVEY OF THE
PESHEKEE RIVER THIS MORNING REVEALED THICK ICE COVERING MOST OF THE
RIVER NEAR AND DOWNSTREAM OF THE CHPM4 RIVER GAUGING LOCATION
/AUTOMATED GAUGE DISCONTINUED BUT OBS ARE BEING TAKEN USING A WIRE
WEIGHT GAUGE AT THE LOCATION/ AND THICK ICE COVER ON MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. A FEW ICE JAMS WERE
NOTED THIS MORNING AND THIS COULD CAUSE SOME ISSUES OVER THE NEXT
COUPLE OF DAYS AS THE RIVER RISES. MAIN STEM RIVERS ARE NOT THE ONLY
HAZARD...AS THERE IS ALSO A THREAT OF AREAL FLOOD PROBLEMS WITH
SMALLER CREEKS/STREAMS AND STANDING WATER ON ROADS. HAVE RECEIVED
SOME SPORADIC REPORTS OF AREAL TYPE FLOODING...WITH THE MOST
WIDESPREAD OVER GOGEBIC COUNTY...SO HAVE ISSUED A AREAL FLOOD
ADVISORY THROUGH TUESDAY FOR GOGEBIC COUNTY. FOR COMPLETE
DETAILS...SEE THE LATEST RIVER FLOOD WATCHES...WARNINGS AND
ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...07
AVIATION...MCD
MARINE...07
HYDROLOGY...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1017 PM CDT WED MAY 1 2013
.UPDATE...
ISSUED AT 1011 PM CDT WED MAY 1 2013
THE POTENT COLD FRONT IS MAKING GOOD PROGRESS INTO THE NWRN
PORTION OF THE CWA AND AT 03Z WAS BI-SECTING LEWIS AND SHELBY
COUNTIES...THEN TRAILED PASS MOBERLY AND INTO WESTERN COOPER
COUNTY. THE PUSH/PROGRESS WAS QUITE A BIT AHEAD OF THE PREVIOUS
FORECAST AND A QUICK LOOK AT THE NEW NAM AND RECENT RUC SUGGEST IT
WILL CONTINUE ITS S/SEWD MARCH. THIS NECESSITATED QUITE A FEW
CHANGES IN THE TONIGHT AND THURSDAY GRIDS TO SPEED THINGS UP DUE
TO THE PREVIOUSLY SLOW FRONTAL PROGRESS. OTHERWISE...THE MAIN
AREA OF RAIN WILL REMAIN WEST OF THE CWA TONIGHT...DEEP INTO THE
COLD AIR. HOWEVER SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS
WILL BE POSSIBLE IN A CORRIDOR AHEAD OF THE COLD FRONT AND IN THE
WAKE OF THE COLD FRONT IN RESPONSE TO LOW LEVEL WAA/MOISTURE
CONVERGENCE VIA SELY LOW LEVEL FLOW.
GLASS
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 405 PM CDT WED MAY 1 2013
EWD PUSH OF STRONG COLD FRONT ACROSS AREA WILL CONTINUE TO BE AT A
SNAILS PACE OVERNIGHT. HAVE GONE WITH A CONSENSUS OF
LOCALWRF...NAM...AND SREF FOR ITS MOVEMENT...WHICH SUGGESTS FRONT
WILL BE CREEPING THROUGH UIN AND COU AREAS DURING THE PREDAWN HOURS.
OBVIOUSLY OVERNIGHT LOWS WILL BE DETERMINED BY THE EARLY MORNING
FRONTAL POSITION....BUT IN GENERAL HAVE LEANED TOWARDS THE WARMER
GUIDANCE DUE TO THE SLOW FRONTAL MOVEMENT.
SPOTTY AMS CONVECTION OVER E OZARKS/S IL SHOULD BE DISSIPATING OVER
THE NEXT FEW HOURS. WE THEN HAVE INTRODUCED SOME SLIGHT CHANCE POPS
OVER NW SECTIONS OF THE CWA LATER THIS EVENING AND OVERNIGHT AS NAM
FORECAST SOUNDINGS ARE INDICATING A WINDOW OF OPPORTUNITY FOR SOME
ELEVATED CONVECTION IN THE VICINITY OF THE FRONT...BUT IN GENEARL
THINK THAT MOST OF THE AREA WILL BE IN FOR A RATHER LONG WAIT UNTIL
THE MORE SIGNIFICANT PRECIPITATION MOVES IN.
TRUETT
.LONG TERM...(THURSDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 400 PM CDT WED MAY 1 2013
UNUSUAL WX PATTERN FOR EARLY MAY AS THE UPPER LEVEL TROUGH OVER THE
NRN PLAINS DEEPENS...EVENTUALLY CUTTING OFF OVER THE PLAINS THU NGT
AND DEEPENS FRI AND FRI NGT. THE MODELS STILL DIFFER ON THE
POSITION AND TRACK OF THE UPPER LEVEL LOW WITH THE GFS FURTHER S
COMPARED TO THE NAM AND ECMWF MODELS. THE STRONG COLD FRONT WILL
MOVE SLOWLY SEWD THROUGH OUR FORECAST AREA ON THU AS THE UPPER LEVEL
TROUGH DEEPENS OVER THE PLAINS. IT APPEARS THAT MOST OF THE
PRECIPITATION WILL CONTINUE TO BE POST FRONTAL WITH THE CHANCE OF
RAIN GRADUALLY INCREASING FROM NW TO SE ON THU WITH THE PROGRESSION
OF THE FRONT. TEMPERATURES SHOULD FALL DURING THE AFTN ACROSS MOST
OF OUR AREA...EXCEPT SWRN IL AS COLDER AIR FILTERS SEWD INTO THE
REGION BEHIND THE FRONT ALONG WITH LOW LEVEL CLOUD COVER AND
FAIRLY WIDESPREAD PRECIPITATION. SHOULD HAVE WIDESPREAD AND
POSSIBLY HEAVY RAINS THU NGT AND FRI AS THE UPPER LEVEL LOW
DEVELOPS AND DEEPENS W OF OUR AREA AND CAUSES A SFC LOW TO DEVELOP
ALONG THE FRONT. WILL ISSUE A HDROLOGIC OUTLOOK FOR MAINLY THE
PERIOD FROM THU NGT THROUGH FRI NGT AS RAINFALL AMOUNTS OF 1 TO 2
INCHES ARE EXPECTED WITH LOCALLY HIGHER AMOUNTS WHICH COULD LEAD
TO SOME FLOOD POTENTIAL AND RIVERS AND CREEKS COMING UP TO
BANKFULL. THE NAM MODEL APPEARS A LITTLE TOO COLD ON TEMPERATURES
THU NGT THROUGH FRI NGT AND FOR NOW WILL GO WITH A BLEND OF NAM
AND GFS MOS GUIDANCE. EVEN SO WE WILL EXPERIENCE MUCH COOLER
TEMPERATURES FOR THU NGT THROUGH FRI NGT AND WELL BELOW NORMAL FOR
EARLY MAY. THE BETTER THREAT FOR PRECIPITATION SHOULD SHIFT EWD
INTO IL FRI NGT AS A DRY SLOT MOVES N-NEWD INTO PORTIONS OF CNTRL
AND SERN MO. THE PRECIPITATION WILL LIKELY BE MORE SCATTERED AND
POSSIBLY LIGHTER ON SAT AS THE UPPER LEVEL LOW AND ASSOCIATED
OCCLUDED SFC LOW MOVES SLOWLY THROUGH SWRN MO PER THE NAM AND
ECMWF FORECASTS...THE GFS MODEL APPEARS A LITTLE TOO FAR S WITH
TRACK OF UPPER LEVEL LOW. WITH HAVE LINGERING SHOWERS SAT NGT AND
SUN AS THE UPPER LEVEL LOW MOVES SLOWLY EWD THROUGH SERN MO AND
SRN IL WITH CONTINUED UNSEASONABLY COLD TEMPERATURES. WILL BEGIN
TO SEE A WARMING TREND FOR THE EARLY PORTION OF THE NEXT WORK WEEK
AS THE UPPER LEVEL LOW FINALLY MOVES WELL E OF OUR AREA.
GKS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 645 PM CDT WED MAY 1 2013
LATEST SURFACE ANALYSIS SHOWS COLD FRONTAL BOUNDARY EXTENDING FROM
EASTERN WISCONSIN THROUGH NORTHWEST MISSOURI AND SOUTHWEST INTO
CENTRAL OKLAHOMA WHERE THE FRONT BECOMES STATIONARY. THE COLD
FRONT IS EXPECTED TO SLIDE SLOWLY SOUTHEAST AND MOVE ACROSS THE
UIN AND COU SITES AROUND 0700 UTC AND ACROSS STL SUS AREAS AROUND
1400 UTC. CIGS WILL BE DROPPING TO 3 TO 5 KFT AFTER THE PASSAGE OF
THE COLD FRONT. CIGS WILL FURTHER DROP BELOW 1 KFT OVER UIN AND
COU AFTER 1600 UTC AND OVER STL - SUS AREAS AFTER 2100 UTC VSBYS
WILL FALL TO 3 TO 5 MI IN RA AND LGT FOG. WIND SPEEDS WILL
INCREASE FROM THE NORTH TO SPEEDS OF 10 TO 12KTS AFTER 2100 UTC
OVER COU...UIN AREAS AND AFTER 2300 UTC OVER STL..SUS AREAS. .
SPECIFICS FOR KSTL...THIS EVENING HIGH LEVEL CLOUDS WITH SOUTHEAST
WINDS OF 5 TO 8 KTS EXPECTED. CIGS WILL DROP TO 3-5KFT AFTER 1000
UTC. AFTER 1800 UTC LGT RAIN AND FOG WILL DEVELOPING WITH VSBYS
DROPPING TO 3 TO 5 MILES AND CIGS BELOW 1 KT.
PRZYBYLINSKI
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1153 PM CDT MON APR 29 2013
.UPDATE...
ISSUED AT 912 PM CDT MON APR 29 2013
HAVE REMOVED RAIN CHANCES FOR TONIGHT. THUNDERSTORMS HAVE DEVELOPED
IN THE LAST 1-2 HOURS WELL NORTH OF THE CWA IN NORTH CENTRAL AND
NORTHEAST IOWA ALONG A WARM FRONT. CHANCES FOR RAIN OVER NORTHEAST
MO/WEST CENTRAL IL LOOK TO BE DIMINISHING AS 00Z 700MB UPPER
ANALYSIS SHOWED WEAK WARM AIR ADVECTION MOVING INTO NORTHERN MO.
RAP FORECAST SOUNDING AT KUIN DOES SHOW WARMING BETWEEN 900-700MB
OVERNIGHT WITH WEAKENING CAPE.
LITTLE CHANGE NEEDED TO THE REST OF THE FORECAST AS GRADIENT WINDS
WILL STAY UP ENOUGH TO KEEP TEMPERATURES FROM FALLING BELOW GOING
LOWS.
BRITT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 256 PM CDT MON APR 29 2013
PRIMARY WEATHER CONCERN FOR TONIGHT IS THE POSSIBILITY OF CONVECTION
ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS. RUC CONTINUES
TO FORECAST COPIOUS AMOUNTS OF CAPE SOUTH OF A Q-STATIONARY FRONT
EXTENDING THROUGH NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA AND
WESTERN IOWA LATE THIS AFTERNOON. GREATEST VALUES EXCEED 4000 J/KG
ACROSS PARTS OF WESTERN AND CENTRAL MISSOURI. HOWEVER...RUC ALSO
APPEARS TO BE 3 TO 5 DEGREES TOO MOIST ON DEWPOINT FORECASTS LATER
THIS AFTERNOON INTO THE EVENING WHICH WOULD DEFINITELY ACCOUNT FOR
THE GIHEMOUS CAPE VALUES. THAT BEING SAID...THERE IS SOME
AGITATED CU OVER SOUTH CENTRAL MISSOURI AND ONE LONE THUNDERSTORM
OVER NORTHERN ARKANSAS...SO THERE`S OBVIOUSLY SOME INSTABILITY OUT
THERE. CURRENT THINKING IS THAT THE ISOLATED CONVECTION OVER SOUTH
CENTRAL MISSOURI WON`T MAKE IT TO OUR AREA...AND THAT CONVECTION
WILL FIRE CLOSER TO THE BAROCLINIC ZONE IN NEBRASKA LATE THIS
AFTERNOON/EARLY EVENING AND RIDE UP ACROSS IOWA. COULD SEE THE TAIL
END OF ANY CONVECTIVE COMPLEX THAT FORMS AFFECT NORTHERN PORTIONS OF
THE CWFA SO HAVE KEPT LOW CHANCE POPS UP THERE. OTHERWISE...SHOULD
BE MILD AND QUIET NIGHT.
CARNEY
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 256 PM CDT MON APR 29 2013
TUESDAY THROUGH THURSDAY...CONFIDENCE MEDIUM
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND WEDNESDAY
AHEAD OF THE DIGGING TROF AND COLD FRONT. CAN`T ARGUE MUCH WITH MOS
GUIDANCE WITH HIGHS IN THE LOWER TO MIDDLE 80S AND LOWS IN THE 60S.
MODEL GUIDANCE IN GOOD AGREEMENT THAT COLD FRONT WILL WAIT UNTIL
WEDNESDAY NIGHT AND THURSDAY MORNING TO START MOVING ACROSS THE CWA.
PRECIPITATION CHANCES TO INCREASE FROM THE WEST...BUT BELIEVE A
LARGE PART OF THE CWA WILL REMAIN DRY THROUGH THURSDAY MORNING.
THIS WILL CHANGE THURSDAY AFTERNOON. THE MAIN BAND OF RAIN WILL EDGE
INTO CENTRAL AND NORTHEAST MISSOURI...WHILE CONVECTION FIRES ON THE
FRONT ITSELF ALONG AND EAST OF THE MISSISSIPPI RIVER. I AM SURE
SOMEONE IN THE MIDDLE OF THESE TWO AREAS OF PRECIPITATION MAY REMAIN
DRY...BUT IT IS TOO FAR OUT TO GET TOO CUTE WITH POP GRADIENTS.
SHOULD BE QUITE A TEMPERATURE CONTRAST ACROSS THE CWA ON THURSDAY
WITH STEADY OR SLOWLY FALLING TEMPERATURES IN THE 40S IN THE WESTERN
CWA...TO THE LOW/MIDDLE 70S IN SOUTH CENTRAL ILLINOIS.
FRIDAY THROUGH MONDAY...CONFIDENCE LOW
MODELS ARE STILL HAVING SOME DIFFICULTY IN HOW THEY HANDLE THE TRACK
OF THE CLOSED OFF LOW LATE THIS WEEK AND WEEKEND. PREFER TO KEEP
FORECAST TREND THE SAME...ESSENTIALLY FOLLOWING HPC GUIDANCE AND 12Z
ECWMF...WITH THE CLOSED OFF LOW DEVELOPING TO OUR WEST AND SPINNING
NORTHEAST ACROSS THE MIDWEST TOWARD THE GREAT LAKES THIS WEEKEND.
MARCHED THE MAIN BAND OF RAIN EAST THURSDAY NIGHT AND FRIDAY WITH
LIKELY POPS AND THEN CONTINUED LOW CHANCE POPS FOR RAIN SHOWERS
THROUGH MONDAY AS AREA EXPECTED TO REMAIN AT LEAST IN THE
VICINITY OF THE COLD CORE SYSTEM. FORECAST RAINFALL AMOUNTS WITH
THIS SOLUTION WOULD BE ON THE ORDER OF 1 TO 1.5 INCHES FOR THE
EVENT.
TEMPERATURES STILL ON TRACK TO FALL BACK BELOW NORMAL FRIDAY AND
SATURDAY...BUT SLOWLY WARM SUNDAY AND MONDAY AS INFLUENCE OF THE
SYSTEM WAINS BY THE BEGINNING OF NEXT WEEK.
NOTE...THE 12Z GFS AND GEM CAME IN QUITE A BIT FURTHER TO THE
SOUTHWEST AND MUCH SLOWER WITH THE SYSTEM...WHICH WOULD RESULT IN A
PROLONGED PERIOD OF RAIN AS THE FRONT AND TROPICAL FETCH PARK ITSELF
ACROSS THE MISSISSIPPI RIVER VALLEY FOR THE ENTIRE WEEKEND. THIS
SOLUTION WOULD YIELD WIDESPREAD RAINFALL AMOUNTS IN EXCESS OF 2
INCHES...WITH SOME LOCALS OVER 4 INCHES.
CVKING
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM CDT MON APR 29 2013
VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST PERIOD. SO MAIN
ISSUE CONTINUES TO BE THE WINDS AND LLWS OVER REGION. WITH LIGHT
SOUTH WINDS AT SURFACE AND STRONG SOUTHWEST LOW LEVEL JET...LLWS A
GOOD BET OVER CENTRAL/NORTHEAST MO...WEST CENTRAL IL...SO KEPT
MENTION IN TAFS. OTHERWISE...THESE GUSTY WINDS TO MIX DOWN TO THE
SURFACE WITH GUSTS TO NEAR 25KTS AT TIMES BY MID MORNING...BEFORE
DIMINISHING AFTER 02Z WEDNESDAY. SOME DIURNAL CU IS POSSIBLE
BEFORE DISSIPATING TOWARDS SUNSET.
SPECIFICS FOR KSTL...VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST
PERIOD. SO MAIN ISSUE CONTINUES TO BE THE WINDS. LIGHT SOUTH WINDS
TO PREVAIL THROUGH 15Z TUESDAY...THEN GUSTY WINDS ALOFT TO MIX
DOWN TO THE SURFACE WITH GUSTS TO NEAR 25KTS AT TIMES...BEFORE
DIMINISHING AFTER 02Z WEDNESDAY. SOME DIURNAL CU IS POSSIBLE
BEFORE DISSIPATING TOWARDS SUNSET. STILL SOME CONCERN THAT WINDS
COULD VEER A BIT MORE TO THE SOUTHWEST ON TUESDAY AFFECTING RUNWAY
CONFIGURATION...WILL KEEP AN EYE ON IT FOR NOW.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
815 PM MDT WED MAY 1 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
RADAR STILL SHOWING RADAR RETURNS MAINLY OVER PHILLIPS COUNTY THIS
EVENING...AND SEEMS TO BE TIED WITH AN UPPER DISTURBANCE. THIS
MOVES EAST OVERNIGHT BUT MUCH OF THIS WILL NOT REACH THE GROUND AS
IT/S RATHER DRY AT THE LOWER LEVELS. GFS SHOWING THE MOST ROBUST
QPF DROPPING A HUNDREDTH OR TWO ACROSS THE NORTHERN ZONES. THE NAM
IS COMPLETELY DRY AND THE HRRR AND SREF ARE IN BETWEEN. CARRIED
SLIGHT CHANCE POPS OVER THE NW ZONES FOR THIS EVENING.
OTHERWISE LOWERED TEMPS A BIT WITH CLEARING LATER ON AND LIGHT
WINDS. JAMBA
PREVIOUS SHORT TERM DISCUSSION...
ISOLATED RAIN AND SNOW SHOWERS WILL CONTINUE ACROSS THE
WEST...AND POSSIBLY THE NORTH INTO THE EARLY EVENING HOURS. SHOWER
ACTIVITY WILL DECREASE WITH THE SETTING OF THE SUN. NORTHWEST
WINDS WILL ALSO TAPER OFF TO LIGHT AND VARIABLE AS THE ATMOSPHERE
STABILIZES AROUND SUNSET. PARTLY CLOUDY SKIES AND AN OVERALL
WARMER AIRMASS WILL MAKE FOR WARMER OVERNIGHT LOWS THEN LAST
NIGHTS FROSTY READINGS. WITH THAT SAID TEMPERATURES WILL BE BELOW
FREEZING ACROSS ALL OF NORTHEAST MONTANA SO GARDENERS ARE ADVISED
TO COVER ANY SUSCEPTIBLE VEGETATION.
UPPER LEVEL NORTHWEST FLOW WILL DOMINATE ON THURSDAY...MAKING FOR
DRY CONDITIONS. TEMPERATURES WILL WARM NICELY INTO THE UPPER 50S
TO LOWER 60S AT MOST LOCATIONS UNDER PARTLY CLOUDY SKIES. WINDS
WILL BE SOUTHWESTERLY ACROSS MOST OF THE AREA...THANKS TO A
LEE SIDE TROUGH ALONG THE FRONT RANGE.
THURSDAY NIGHT CLOUD COVER WILL BE ON THE INCREASE AHEAD OF AN
APPROACHING DISTURBANCE IN THE NORTHWEST FLOW ALOFT. A WARMING
AIRMASS WILL MAKE FOR WARMER OVERNIGHT LOWS THEN WE HAVE SEEN AS OF
LATE. WITH THAT SAID A FEW AREAS...MAINLY ACROSS THE EAST COULD
STILL SEE NEAR FREEZING TEMPS.
FRIDAY THE AFOREMENTIONED DISTURBANCE WILL BEGIN IMPACTING
NORTHEAST MONTANA. MOSTLY CLOUDY SKIES CAN BE EXPECTED WITH
INCREASING CHANCES FOR SHOWERS ACROSS THE WESTERN HALF OF THE
FORECAST AREA. TIMING OF THE ASSOCIATED COLD FRONT IS A BIT UP IN
THE AIR THIS FAR OUT...HOWEVER DID WARM TEMPS ACROSS THE SOUTHEAST
AS COMPRESSIONAL WARMING THERE AHEAD OF THE FRONT IS A GOOD BET.
NORTHWEST WINDS WILL ALSO DEVELOP BEHIND THE FRONT AS WELL AT 10
TO 20 MPH. GILCHRIST
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE SHORT WAVE TROUGH ENERGY WHICH SLIPS INTO MONTANA FROM THE
NORTH FRIDAY NIGHT QUICKLY PUSHES SOUTHWESTWARD AND FORMS INTO A
CLOSED LOW PRESSURE SYSTEM OVER CALIFORNIA BY EARLY SUNDAY
MORNING. BY THE TIME THIS HAPPENS...IT SEEMS TO BE FAR ENOUGH
REMOVED FROM NORTHEAST MONTANA TO KEEP PRECIPITATION AWAY AS AN
ARCING IS FOUND ON THE NORTH EDGE OF THE CALIFORNIA LOW.
MONDAY THROUGH WEDNESDAY SEEMS TO SHOW A VERY BENIGN UPPER LEVEL
FLOW PATTERN OVER NORTHEAST MONTANA. THE SIGNIFICANT MODEL
DISCREPANCIES BETWEEN THE COLDER EC TROUGH AND THE WARMER GFS
RIDGE CONTINUE...BUT THE 12Z RUN OF THE EC HAS NOW BACKED OFF A
BIT TO SHOW A NOT QUITE AS COLD SOLUTION.
I GENERALLY CUT BACK POPS A BIT TO FOLLOW AND BLEND WITH THE LONG
TERM MODEL AGREEMENT SHOWING A BIT OF A DRIER CONSENSUS. BMICKELSON
PREVIOUS LONG TERM DISCUSSION...VARIOUS MODELS HAVE BEEN FOR THE
LAST COUPLE DAYS MAINTAINING A MODEST BUT PERSISTENT SHORTWAVE
FEATURE THAT MOVES OFF OF THE CANADIAN ROCKIES INTO MONTANA ON
FRIDAY. THIS LEADS TO SOME POPS FRIDAY NIGHT AND SATURDAY. THE
SHORTWAVE PASSAGE SATURDAY IS THE BEST DEFINED EVENT IN THE
EXTENDED FORECAST...AND PROVIDES THE BEST CHANCE FOR RAIN. BEYOND
SATURDAY A LARGE PACIFIC RIDGE TENDS TO KEEP IMPULSES AWAY FROM
THE AREA...THOUGH THE EC MODEL HAS A SOMEWHAT WEAKER RIDGE WHICH
ALLOWS SOME ENERGY INTO THE AREA.
THE GFS ENSEMBLE ITSELF MAINTAINS REASONABLE COHERENCE BEYOND
SUNDAY...BUT THE DISAGREEMENT BETWEEN THE GFS AND THE MORE
POWERFUL EC MODEL BECOMES SIGNIFICANT BY SUNDAY EVENING WITH THE
GFS BUILDING A LARGE RIDGE OVER THE PACIFIC NORTHWEST...WHERE THE
EC HAS A FLATTER RIDGE. THIS DIVERGENCE GROWS AND BY TUESDAY...THE EC
HAS A MARKED SHORTWAVE GENERATING SOME WEATHER OVER THE GLASGOW
CWA WHILE THE GFS HAS THE AREA UNDER A RIDGE. THIS GIVES US POOR
GUIDANCE AFTER MONDAY AND NO EFFECTIVE GUIDANCE BEYOND TUESDAY.
THUS THE FORECAST NEEDS TO TREND TOWARDS CLIMATOLOGY FOR THESE
LATER PERIODS.
TEMPERATURES FOR THE LONG TERM SHOULD TREND TOWARDS SEASONAL
NORMAL TO ABOVE NORMAL...GIVEN THE FORECAST RIDGING...WITH NO
FROST IN THE FORECAST. STRONGEST WINDS SATURDAY THROUGH WEDNESDAY
WILL OCCUR WITH THE PASSAGE OF THE SHORTWAVE SYSTEM ON
SATURDAY...AND ARE NOT EXPECTED TO BE PARTICULARLY STRONG. MARTIN
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED FOR ALL TAF SITES TONIGHT AND
THURSDAY...ALTHOUGH BRIEF EVENING SHOWERS ARE POSSIBLE. LIGHT AND
VARIABLE WINDS TONIGHT WILL ACCOMPANY A CLOUD DECK OF AROUND 6K
FT. SKIES WILL CLEAR AGAIN BY EARLY THURSDAY MORNING WITH LIGHT
AND VARIABLE WIND THAT BECOMES MORE SOUTHERLY IN THE AFTERNOON.
SCT
&&
.HYDROLOGY...
AS THE SPRING THAW CONTINUES...CREEKS AND STREAMS IN FAR NORTHEAST
MONTANA WILL CONTINUE TO RUN HIGH. THE POPLAR RIVER...THE EAST
FORK OF THE POPLAR RIVER AND BIG MUDDY CREEK WILL MAINTAIN HIGHER
WATER LEVELS INTO EARLY MAY AS THE REMAINING SNOW OVER SOUTHERN
SASKATCHEWAN MELTS. MINOR SMALL STREAM AND LOW LAND FLOODING WILL
BE POSSIBLE.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
114 PM CDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM CDT TUE APR 30 2013
CLEARLY THE MAIN CONCERN DURING THE NEXT 24 HOURS IS THE RISK FOR
POTENTIALLY SEVERAL STRONG TO SEVERE STORMS MAINLY BETWEEN 7 PM
AND 3 AM TONIGHT...AND MAINLY WITHIN THE SOUTHEAST 1/2 OF THE CWA.
OTHERWISE...TODAY MARKS THE TRANSITION DAY BETWEEN THE 80+ DEGREE
WARMTH OF THE PAST FEW DAYS...AND THE UNWELCOME RETURN TO A WINTRY
FEEL TOMORROW.
09Z OBJECTIVE SURFACE ANALYSIS IS HIGHLIGHTED BY THE MUCH-
ADVERTISED COLD FRONT...THAT PER AUTOMATED OBS AND RADAR IMAGERY
IS ALREADY WELL THROUGH AT LEAST THE NORTHWEST 1/3 OF THE
CWA...AND CONTINUES STEADILY PASSING SOUTHEAST. BEHIND THE FRONT
ARE NORTH-NORTHWEST WINDS WITH SUSTAINED SPEEDS GENERALLY 10-20
MPH WITH HIGHER GUSTS. THIS FRONT IS CONNECTED ACROSS THE REGION
BY TWO PRIMARY SURFACE LOW CENTERS...A 991 MILLIBAR NEAR THE
SD/ND/MN BORDER...AND A 996MB ONE ALONG THE KS/CO BORDER. AHEAD OF
THE FRONT...STEADY SOUTH-SOUTHWEST BREEZES 10-20 MPH HAVE BEEN THE
NORM THROUGH THE NIGHT...PROMOTING VERY MILD READINGS MAINLY IN
THE 60S. ALTHOUGH TEMPS ARE FALLING OFF SOMEWHAT BEHIND THE
BOUNDARY...A GOOD CHUNK OF THE CWA SHOULD MAKE IT THROUGH 8AM
WITHOUT DROPPING BELOW THE 55-60 RANGE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A LARGE SCALE TROUGH
AND ASSOCIATED UPPER JET STREAK CENTERED OVER THE NORTHERN
PLAINS/ROCKIES...WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS...THE
MOST VIGOROUS OF WHICH IS SWINGING ALONG THE SD/CANADA BORDER.
FOR THE 7AM-7PM DAYTIME PERIOD...THE VAST MAJORITY...IF NOT THE
ENTIRE CWA SHOULD REMAIN THUNDERSTORM/RAIN FREE...AND ONLY HAVE A
SLIGHT CHANCE OF STORMS AFTER 5 PM IN FAR SOUTHEAST ZONES MAINLY
SOUTHEAST OF A HEBRON-PLAINVILLE LINE. ALOFT...BROAD WEST-
SOUTHWEST FLOW WILL PERSIST OVER THE CENTRAL PLAINS...AS THE
VIGOROUS VORT MAX OVER SD SWINGS NORTHEAST INTO CANADA...WHILE
ADDITIONAL PIECES OF ENERGY SLIDE SOUTHEAST OUT OF THE NORTHWEST
CONUS TOWARD THE CENTRAL ROCKIES...HELPING TO SLOWLY DEEPEN THE
DEVELOPING POSITIVELY TILTED LARGE SCALE TROUGH. AT THE
SURFACE...THE COLD FRONT WILL CONTINUE MAKING STEADY PROGRESS
SOUTHWARD ACROSS THE CWA TODAY...ALTHOUGH IT WILL SLOW AND
ESSENTIALLY STALL OUT AS IT REACHES FAR SOUTHEAST COUNTIES...AS IT
IS COUNTER-ACTED BY A STRENGTHENING WARM FRONT/INVERTED TROUGH
AXIS EXTENDING NORTHEAST FROM A DEEPENING SURFACE LOW NEAR THE
CO/OK/KS/TX BORDER AREA. FOR THE MAJORITY OF THE CWA THAT GETS
BEHIND THE COLD FRONT TODAY...BREEZES WILL AVERAGE AT LEAST 15-20
MPH WITH HIGHER GUSTS...AS THE WIND DIRECTION GRADUALLY SHIFTS
FROM NORTHERLY TO NORTHEASTERLY. TEMPERATURE-WISE...DESPITE
PASSING HIGH CLOUDS...ITS NOW LOOKING LIKE THERE WILL BE ENOUGH
SUNSHINE...AND ALSO WEAK ENOUGH COLD AIR ADVECTION TO ALLOW TEMPS
TO CLIMB HIGHER THAN PREVIOUSLY FORECAST...AND BASED ON A BLEND OF
VARIOUS MODELS/GUIDANCE HAVE RAISED HIGHS ROUGHLY 5 DEGREES ALL
AREAS...NOW AIMING FOR MID 60S NORTHWEST...NEAR 70 CENTRAL...AND
LOW 80S FAR SOUTHEAST. IF THE RAP MODEL IS ONTO SOMETHING...IT MAY
BE EVEN WARMER YET...BUT HAVE LARGELY DISCOUNTED IT FOR NOW. AS
FOR PRE-7PM STORM CHANCES...THEY ARE LOOKING FAIRLY SLIM DESPITE
THE LATEST NAM BUILDING 1000+ J/KG OF 0-1MLCAPE IN FAR SOUTHEAST
ZONES LATE THIS AFTERNOON. FORECAST SOUNDINGS SHOW A PRETTY
FORMIDABLE CAP TO SURFACE-BASED CONVECTION OWING TO WARM 700MB
TEMPS IN AN ELEVATED MIXED LAYER. PER REFLECTIVITY FORECAST FROM
THE 00Z 4KM WRF-NMM AND ALSO THE 09Z RAP...THAYER AND MITCHELL
COUNTIES WOULD BEAR THE MOST WATCHING FOR POSSIBLE STORM
DEVELOPMENT...WHICH COULD BECOME SEVERE QUICKLY SHOULD IT FORM.
ALTHOUGH A BRIEF NEAR-SURFACE BASED SUPERCELL CANNOT BE RULED
OUT...IT WOULD LIKELY TAKE ON A SOMEWHAT LINEAR TENDENCY PRETTY
QUICKLY WITH FLOW ALOFT PARALLEL TO THE LOW LEVEL FRONTAL ZONE.
TURNING TO THE 7PM-7AM TONIGHT PERIOD...CONFIDENCE IS CONSIDERABLY
HIGHER IN WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT...ESPECIALLY
AFTER SUNSET...AND POPS HAVE BEEN BUMPED UP INTO THE 80-90 PERCENT
RANGE FOR MUCH OF THE NIGHT. ALOFT...SHORTWAVE ENERGY WILL
TRANSLATE INTO THE PLAINS FROM THE WEST AS THE PARENT LONGWAVE
TROUGH SETS UP ALONG AN AXIS FROM ND TO THE CENTRAL ROCKIES BY
SUNRISE WEDNESDAY MORNING. WITHIN THE ENTRANCE REGION OF A DAKOTAS
UPPER JET STREAK...LOW-MID LEVEL SOUTHERLY WINDS SPEEDS/RESULTANT
MOISTURE CONVERGENCE WILL RAMP UP MARKEDLY AROUND/AFTER
SUNSET INTO THE FRONTAL ZONE...WITH MOISTURE TRANSPORT SURGING
INTO THE CWA EVIDENT AT BOTH 850 AND 700MB. VARIOUS MODEL
QPF/REFLECTIVITY PROGS SUCH AS FROM THE NAM AND 4KM WRF-NMM AGREE
ON THE SCENARIO OF A RAPID INCREASE IN THUNDERSTORM DEVELOPMENT
THIS EVENING ACROSS MOST IF NOT ALL OF THE CWA...BUT ESPECIALLY
THE SOUTHEAST 1/2. THIS SHOULD BE A FAIRLY CLASSIC SETUP FOR AT
LEAST MARGINALLY SEVERE HAIL AROUND QUARTER SIZE OR SLIGHTLY
LARGER...WITH A CONSENSUS OF THE LATEST NAM/GFS SUGGESTING AT
LEAST 500-1500 J/KG OF MUCAPE IN THE 850-700MB LAYER THROUGH
06Z...IN THE PRESENCE OF DEEP LAYER 0-6KM SHEAR OF GENERALLY 40-60
KT. THIS COULD YIELD AT LEAST A HANDFUL OF ELEVATED SUPERCELL
STRUCTURES TRAINING WITHIN THE SAME GENERAL CORRIDOR...NOT ALL
THAT UNLIKE THE EVENT IN EARLY APRIL THAT AFFECTED MUCH OF THE NEB
CWA. ALTHOUGH A STRONG STORM IS POSSIBLE ALMOST ANYWHERE...THE
GREATEST THREAT FOR LARGE HAIL AND POSSIBLY SEVERE WIND GUSTS
SHOULD RESIDE GENERALLY SOUTH OF AN ELWOOD-OSCEOLA LINE INCLUDING
KS COUNTIES. GRADUALLY DECREASING INSTABILITY SHOULD RESULT IN A
DECREASING SEVERE THREAT BY AROUND 3 AM OR SO...BUT NOT
NECESSARILY SO. SOME PLACES COULD ALSO PICK UP HEALTHY RAINFALL
AMOUNTS OF 1-2+ INCHES...BUT NOT FORESEEING MUCH OF AN ORGANIZED
FLOODING THREAT GIVEN THE RECENT WARM...DRY STRETCH. ALL OF THIS
WILL BE TAKING PLACE IN THE PRESENCE OF STEADY LOW LEVEL COLD AIR
ADVECTION...MARKED BY NORTH-NORTHEAST WINDS OF AT LEAST 20 MPH AND
POSSIBLY CLOSER TO SUSTAINED 30 MPH AT TIMES EVEN OUTSIDE STORM
ACTIVITY. BY SUNRISE WEDNESDAY MORNING...HAVE LOW TEMPS AIMED FROM
THE MID 30S IN NORTHWEST COUNTIES...TO LOW-MID 40S SOUTHEAST. ITS
NOT COMPLETELY OUT OF THE QUESTION THAT SOME SNOW COULD START
MIXING IN WITH RAIN BETWEEN 09Z-12Z...IN FAR NORTHWEST ZONES...BUT
WOULD EXPECT LITTLE IF ANY ACCUMULATION BEFORE SUNRISE...AND EVEN
THEN ONLY IN THE VALLEY/WESTERN DAWSON COUNTY AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM CDT TUE APR 30 2013
BIGGEST CHALLENGE WILL BE DETERMINING TIMING OF CHANGEOVER TO SNOW
WEDNESDAY AND DETERMINING SNOW AMOUNTS THROUGH WEDNESDAY NIGHT.
WE KICK OFF WEDNESDAY WITH A HIGHLY AMPLIFIED UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN WEST THAT WILL CONTINUE TO AMPLIFY AND HEAD
TOWARD THE CENTRAL PLAINS. PLENTY OF COLD AIR ADVECTION WILL BE
UNDERWAY...BUT ELEVATED CONVECTION COULD STILL BE OCCURRING DURING
THE EARLY MORNING ON WEDNESDAY IN OUR SOUTHEAST. PROBABLY NOT ENOUGH
INSTABILITY FOR SEVERE WEATHER ANYMORE. ALSO...TEMPERATURES WILL NOT
GO ANYWHERE ON WEDNESDAY WITH THE STRONG COLD AIR ADVECTION...SO
TEMPERATURES WILL BE STEADY OR FALLING DURING THE DAY WITH MIX OF
SNOW/SNOW WORKING IN TO THE SOUTHEAST DURING THE DAY. WIND WILL BE
QUITE PERSISTENT FROM THE NORTH...ESPECIALLY TO THE SOUTH WITH STRONG
HEIGHT RISES. WE COULD BE PUSHING WIND ADVISORY OVER NORTH CENTRAL
KANSAS.
LOOKS A LITTLE TRICKY FOR TIMING OF SWITCHING OVER TO SNOW...AND
TOWARD A MIDDLE OF THE ROAD APPROACH AMONG MODEL
SOLUTIONS...CONSIDERING TIMING AND QPF AMOUNTS. WE COULD PICK UP ONE
TO THREE INCHES...BUT MOST OF THIS WOULD BE ON GRASSY
SURFACES...CONSIDERING THAT THIS WILL BE IN THE MONTH OF MAY.
ALSO...THE NAM INDICATES A POSSIBLE LOSS OF SATURATION IN THE DENDRITIC
GROWTH ZONE LATE AFTERNOON AND EVENING WEDNESDAY...WHICH COULD GIVE
US SOME DRIZZLE/FREEZING DRIZZLE FOR A SHORT PERIOD. ALSO...SLEET
MIGHT NOT BE OUT OF THE QUESTION ACCORDING TO SOME MODEL
SUGGESTIONS...BUT I WILL LEAVE BOTH OUT FOR NOW...AS IT DOES NOT
LOOK THAT LIKELY FOR MUCH SLEET WITH SUCH STRONG COLD AIR ADVECTION
AND THE LACK OF SATURATION IN THE DENDRITIC GROWTH ZONE IS VERY
DICEY.
WE COULD STILL HAVE SOME LEFTOVER SNOW IN THE SOUTH/EAST ON THURSDAY
MORNING AS THE TROUGH AXIS WILL NOT PASS TO THE EAST OF THE CWA
UNTIL AT LEAST AFTERNOON.
MODELS THEN CLOSE OFF A LOW WITHIN THE TROUGH BY THURSDAY NIGHT AND
TO BE HONEST...IT IS A FREE FOR ALL FRIDAY THROUGH THE REST OF THE
LONG TERM FORECAST AS THERE IS ABSOLUTELY NO AGREEMENT AMONG MODELS
OF WHAT HAPPENS WITH THE UPPER LOW. ENSEMBLES ARE OUT OF PHASE AS
WELL. STAYING WITH CONTINUITY HERE...BUT CONFIDENCE IS NOT HIGH WITH
THE LATEST FORECASTS FROM MODELS. WE CAN ONLY HOPE FOR SOME SORT OF
AGREEMENT DEVELOPING IN THE NEAR FUTURE. THERE IS GREAT POTENTIAL
FOR BIG BUSTS FOR TEMPERATURE FORECASTS...ESPECIALLY HIGH
TEMPERATURES...AND WE COULD VERY WELL END UP MUCH COOLER THAN
CURRENTLY ADVERTISED.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1230 PM CDT TUE APR 30 2013
DETERIORATING CONDITIONS ARE EXPECTED AT KGRI THROUGH THE NEXT 24
HOURS AS CEILINGS LOWER AND VISIBILITIES ARE REDUCED DUE TO
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS NEAR A COLD FRONTAL
BOUNDARY THAT IS DRAPED ACROSS THE FORECAST AREA.
INITIALLY...EXPECT SOME THUNDERSTORMS TO DEVELOP IN THE VICINITY
OF KGRI...LIKELY AFTER 01/03Z...AS A SECONDARY FRONTAL BOUNDARY
APPROACHES THE TERMINAL. MODEL CONSENSUS IS FAIRLY GOOD WITH MORE
WIDESPREAD THUNDERSTORM ACTIVITY AFTER 01/06Z...WITH SUFFICIENT
INSTABILITY LINGERING FOR ADDITIONAL SHOWER AND THUNDERSTORM
DEVELOPMENT THROUGH ABOUT 01/12Z. BEHIND THE SECONDARY COLD
FRONT...EXPECT LIGHT RAIN...POSSIBLY MIXED WITH SNOW LATER IN THE
DAY...TO DEVELOP AFT 01/12Z...WITH SOME AREAS OF REDUCED
VISIBILITIES POSSIBLE ALONG WITH VERY GUSTY NORTHERLY WINDS BEHIND
THE FRONT. AT THIS TIME...EXPECT GUSTS TO REACH 35KTS...OR
POTENTIALLY HIGHER BEHIND THE FRONT WEDNESDAY AFTERNOON...AS
STRONG PRESSURE RISES ARE REALIZED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
706 AM CDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM CDT TUE APR 30 2013
CLEARLY THE MAIN CONCERN DURING THE NEXT 24 HOURS IS THE RISK FOR
POTENTIALLY SEVERAL STRONG TO SEVERE STORMS MAINLY BETWEEN 7 PM
AND 3 AM TONIGHT...AND MAINLY WITHIN THE SOUTHEAST 1/2 OF THE CWA.
OTHERWISE...TODAY MARKS THE TRANSITION DAY BETWEEN THE 80+ DEGREE
WARMTH OF THE PAST FEW DAYS...AND THE UNWELCOME RETURN TO A WINTRY
FEEL TOMORROW.
09Z OBJECTIVE SURFACE ANALYSIS IS HIGHLIGHTED BY THE MUCH-
ADVERTISED COLD FRONT...THAT PER AUTOMATED OBS AND RADAR IMAGERY
IS ALREADY WELL THROUGH AT LEAST THE NORTHWEST 1/3 OF THE
CWA...AND CONTINUES STEADILY PASSING SOUTHEAST. BEHIND THE FRONT
ARE NORTH-NORTHWEST WINDS WITH SUSTAINED SPEEDS GENERALLY 10-20
MPH WITH HIGHER GUSTS. THIS FRONT IS CONNECTED ACROSS THE REGION
BY TWO PRIMARY SURFACE LOW CENTERS...A 991 MILLIBAR NEAR THE
SD/ND/MN BORDER...AND A 996MB ONE ALONG THE KS/CO BORDER. AHEAD OF
THE FRONT...STEADY SOUTH-SOUTHWEST BREEZES 10-20 MPH HAVE BEEN THE
NORM THROUGH THE NIGHT...PROMOTING VERY MILD READINGS MAINLY IN
THE 60S. ALTHOUGH TEMPS ARE FALLING OFF SOMEWHAT BEHIND THE
BOUNDARY...A GOOD CHUNK OF THE CWA SHOULD MAKE IT THROUGH 8AM
WITHOUT DROPPING BELOW THE 55-60 RANGE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A LARGE SCALE TROUGH
AND ASSOCIATED UPPER JET STREAK CENTERED OVER THE NORTHERN
PLAINS/ROCKIES...WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS...THE
MOST VIGOROUS OF WHICH IS SWINGING ALONG THE SD/CANADA BORDER.
FOR THE 7AM-7PM DAYTIME PERIOD...THE VAST MAJORITY...IF NOT THE
ENTIRE CWA SHOULD REMAIN THUNDERSTORM/RAIN FREE...AND ONLY HAVE A
SLIGHT CHANCE OF STORMS AFTER 5 PM IN FAR SOUTHEAST ZONES MAINLY
SOUTHEAST OF A HEBRON-PLAINVILLE LINE. ALOFT...BROAD WEST-
SOUTHWEST FLOW WILL PERSIST OVER THE CENTRAL PLAINS...AS THE
VIGOROUS VORT MAX OVER SD SWINGS NORTHEAST INTO CANADA...WHILE
ADDITIONAL PIECES OF ENERGY SLIDE SOUTHEAST OUT OF THE NORTHWEST
CONUS TOWARD THE CENTRAL ROCKIES...HELPING TO SLOWLY DEEPEN THE
DEVELOPING POSITIVELY TILTED LARGE SCALE TROUGH. AT THE
SURFACE...THE COLD FRONT WILL CONTINUE MAKING STEADY PROGRESS
SOUTHWARD ACROSS THE CWA TODAY...ALTHOUGH IT WILL SLOW AND
ESSENTIALLY STALL OUT AS IT REACHES FAR SOUTHEAST COUNTIES...AS IT
IS COUNTER-ACTED BY A STRENGTHENING WARM FRONT/INVERTED TROUGH
AXIS EXTENDING NORTHEAST FROM A DEEPENING SURFACE LOW NEAR THE
CO/OK/KS/TX BORDER AREA. FOR THE MAJORITY OF THE CWA THAT GETS
BEHIND THE COLD FRONT TODAY...BREEZES WILL AVERAGE AT LEAST 15-20
MPH WITH HIGHER GUSTS...AS THE WIND DIRECTION GRADUALLY SHIFTS
FROM NORTHERLY TO NORTHEASTERLY. TEMPERATURE-WISE...DESPITE
PASSING HIGH CLOUDS...ITS NOW LOOKING LIKE THERE WILL BE ENOUGH
SUNSHINE...AND ALSO WEAK ENOUGH COLD AIR ADVECTION TO ALLOW TEMPS
TO CLIMB HIGHER THAN PREVIOUSLY FORECAST...AND BASED ON A BLEND OF
VARIOUS MODELS/GUIDANCE HAVE RAISED HIGHS ROUGHLY 5 DEGREES ALL
AREAS...NOW AIMING FOR MID 60S NORTHWEST...NEAR 70 CENTRAL...AND
LOW 80S FAR SOUTHEAST. IF THE RAP MODEL IS ONTO SOMETHING...IT MAY
BE EVEN WARMER YET...BUT HAVE LARGELY DISCOUNTED IT FOR NOW. AS
FOR PRE-7PM STORM CHANCES...THEY ARE LOOKING FAIRLY SLIM DESPITE
THE LATEST NAM BUILDING 1000+ J/KG OF 0-1MLCAPE IN FAR SOUTHEAST
ZONES LATE THIS AFTERNOON. FORECAST SOUNDINGS SHOW A PRETTY
FORMIDABLE CAP TO SURFACE-BASED CONVECTION OWING TO WARM 700MB
TEMPS IN AN ELEVATED MIXED LAYER. PER REFLECTIVITY FORECAST FROM
THE 00Z 4KM WRF-NMM AND ALSO THE 09Z RAP...THAYER AND MITCHELL
COUNTIES WOULD BEAR THE MOST WATCHING FOR POSSIBLE STORM
DEVELOPMENT...WHICH COULD BECOME SEVERE QUICKLY SHOULD IT FORM.
ALTHOUGH A BRIEF NEAR-SURFACE BASED SUPERCELL CANNOT BE RULED
OUT...IT WOULD LIKELY TAKE ON A SOMEWHAT LINEAR TENDENCY PRETTY
QUICKLY WITH FLOW ALOFT PARALLEL TO THE LOW LEVEL FRONTAL ZONE.
TURNING TO THE 7PM-7AM TONIGHT PERIOD...CONFIDENCE IS CONSIDERABLY
HIGHER IN WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT...ESPECIALLY
AFTER SUNSET...AND POPS HAVE BEEN BUMPED UP INTO THE 80-90 PERCENT
RANGE FOR MUCH OF THE NIGHT. ALOFT...SHORTWAVE ENERGY WILL
TRANSLATE INTO THE PLAINS FROM THE WEST AS THE PARENT LONGWAVE
TROUGH SETS UP ALONG AN AXIS FROM ND TO THE CENTRAL ROCKIES BY
SUNRISE WEDNESDAY MORNING. WITHIN THE ENTRANCE REGION OF A DAKOTAS
UPPER JET STREAK...LOW-MID LEVEL SOUTHERLY WINDS SPEEDS/RESULTANT
MOISTURE CONVERGENCE WILL RAMP UP MARKEDLY AROUND/AFTER
SUNSET INTO THE FRONTAL ZONE...WITH MOISTURE TRANSPORT SURGING
INTO THE CWA EVIDENT AT BOTH 850 AND 700MB. VARIOUS MODEL
QPF/REFLECTIVITY PROGS SUCH AS FROM THE NAM AND 4KM WRF-NMM AGREE
ON THE SCENARIO OF A RAPID INCREASE IN THUNDERSTORM DEVELOPMENT
THIS EVENING ACROSS MOST IF NOT ALL OF THE CWA...BUT ESPECIALLY
THE SOUTHEAST 1/2. THIS SHOULD BE A FAIRLY CLASSIC SETUP FOR AT
LEAST MARGINALLY SEVERE HAIL AROUND QUARTER SIZE OR SLIGHTLY
LARGER...WITH A CONSENSUS OF THE LATEST NAM/GFS SUGGESTING AT
LEAST 500-1500 J/KG OF MUCAPE IN THE 850-700MB LAYER THROUGH
06Z...IN THE PRESENCE OF DEEP LAYER 0-6KM SHEAR OF GENERALLY 40-60
KT. THIS COULD YIELD AT LEAST A HANDFUL OF ELEVATED SUPERCELL
STRUCTURES TRAINING WITHIN THE SAME GENERAL CORRIDOR...NOT ALL
THAT UNLIKE THE EVENT IN EARLY APRIL THAT AFFECTED MUCH OF THE NEB
CWA. ALTHOUGH A STRONG STORM IS POSSIBLE ALMOST ANYWHERE...THE
GREATEST THREAT FOR LARGE HAIL AND POSSIBLY SEVERE WIND GUSTS
SHOULD RESIDE GENERALLY SOUTH OF AN ELWOOD-OSCEOLA LINE INCLUDING
KS COUNTIES. GRADUALLY DECREASING INSTABILITY SHOULD RESULT IN A
DECREASING SEVERE THREAT BY AROUND 3 AM OR SO...BUT NOT
NECESSARILY SO. SOME PLACES COULD ALSO PICK UP HEALTHY RAINFALL
AMOUNTS OF 1-2+ INCHES...BUT NOT FORESEEING MUCH OF AN ORGANIZED
FLOODING THREAT GIVEN THE RECENT WARM...DRY STRETCH. ALL OF THIS
WILL BE TAKING PLACE IN THE PRESENCE OF STEADY LOW LEVEL COLD AIR
ADVECTION...MARKED BY NORTH-NORTHEAST WINDS OF AT LEAST 20 MPH AND
POSSIBLY CLOSER TO SUSTAINED 30 MPH AT TIMES EVEN OUTSIDE STORM
ACTIVITY. BY SUNRISE WEDNESDAY MORNING...HAVE LOW TEMPS AIMED FROM
THE MID 30S IN NORTHWEST COUNTIES...TO LOW-MID 40S SOUTHEAST. ITS
NOT COMPLETELY OUT OF THE QUESTION THAT SOME SNOW COULD START
MIXING IN WITH RAIN BETWEEN 09Z-12Z...IN FAR NORTHWEST ZONES...BUT
WOULD EXPECT LITTLE IF ANY ACCUMULATION BEFORE SUNRISE...AND EVEN
THEN ONLY IN THE VALLEY/WESTERN DAWSON COUNTY AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM CDT TUE APR 30 2013
BIGGEST CHALLENGE WILL BE DETERMINING TIMING OF CHANGEOVER TO SNOW
WEDNESDAY AND DETERMINING SNOW AMOUNTS THROUGH WEDNESDAY NIGHT.
WE KICK OFF WEDNESDAY WITH A HIGHLY AMPLIFIED UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN WEST THAT WILL CONTINUE TO AMPLIFY AND HEAD
TOWARD THE CENTRAL PLAINS. PLENTY OF COLD AIR ADVECTION WILL BE
UNDERWAY...BUT ELEVATED CONVECTION COULD STILL BE OCCURRING DURING
THE EARLY MORNING ON WEDNESDAY IN OUR SOUTHEAST. PROBABLY NOT ENOUGH
INSTABILITY FOR SEVERE WEATHER ANYMORE. ALSO...TEMPERATURES WILL NOT
GO ANYWHERE ON WEDNESDAY WITH THE STRONG COLD AIR ADVECTION...SO
TEMPERATURES WILL BE STEADY OR FALLING DURING THE DAY WITH MIX OF
SNOW/SNOW WORKING IN TO THE SOUTHEAST DURING THE DAY. WIND WILL BE
QUITE PERSISTENT FROM THE NORTH...ESPECIALLY TO THE SOUTH WITH STRONG
HEIGHT RISES. WE COULD BE PUSHING WIND ADVISORY OVER NORTH CENTRAL
KANSAS.
LOOKS A LITTLE TRICKY FOR TIMING OF SWITCHING OVER TO SNOW...AND
TOWARD A MIDDLE OF THE ROAD APPROACH AMONG MODEL
SOLUTIONS...CONSIDERING TIMING AND QPF AMOUNTS. WE COULD PICK UP ONE
TO THREE INCHES...BUT MOST OF THIS WOULD BE ON GRASSY
SURFACES...CONSIDERING THAT THIS WILL BE IN THE MONTH OF MAY.
ALSO...THE NAM INDICATES A POSSIBLE LOSS OF SATURATION IN THE DENDRITIC
GROWTH ZONE LATE AFTERNOON AND EVENING WEDNESDAY...WHICH COULD GIVE
US SOME DRIZZLE/FREEZING DRIZZLE FOR A SHORT PERIOD. ALSO...SLEET
MIGHT NOT BE OUT OF THE QUESTION ACCORDING TO SOME MODEL
SUGGESTIONS...BUT I WILL LEAVE BOTH OUT FOR NOW...AS IT DOES NOT
LOOK THAT LIKELY FOR MUCH SLEET WITH SUCH STRONG COLD AIR ADVECTION
AND THE LACK OF SATURATION IN THE DENDRITIC GROWTH ZONE IS VERY
DICEY.
WE COULD STILL HAVE SOME LEFTOVER SNOW IN THE SOUTH/EAST ON THURSDAY
MORNING AS THE TROUGH AXIS WILL NOT PASS TO THE EAST OF THE CWA
UNTIL AT LEAST AFTERNOON.
MODELS THEN CLOSE OFF A LOW WITHIN THE TROUGH BY THURSDAY NIGHT AND
TO BE HONEST...IT IS A FREE FOR ALL FRIDAY THROUGH THE REST OF THE
LONG TERM FORECAST AS THERE IS ABSOLUTELY NO AGREEMENT AMONG MODELS
OF WHAT HAPPENS WITH THE UPPER LOW. ENSEMBLES ARE OUT OF PHASE AS
WELL. STAYING WITH CONTINUITY HERE...BUT CONFIDENCE IS NOT HIGH WITH
THE LATEST FORECASTS FROM MODELS. WE CAN ONLY HOPE FOR SOME SORT OF
AGREEMENT DEVELOPING IN THE NEAR FUTURE. THERE IS GREAT POTENTIAL
FOR BIG BUSTS FOR TEMPERATURE FORECASTS...ESPECIALLY HIGH
TEMPERATURES...AND WE COULD VERY WELL END UP MUCH COOLER THAN
CURRENTLY ADVERTISED.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 700 AM CDT TUE APR 30 2013
VFR CEILING/VISIBILITY ARE CURRENTLY FORECAST THROUGH THE NEXT 24
HOURS...ALTHOUGH THIS IS BY NO MEANS A SURE-THING DURING THE FINAL
6-9 HOURS OF THE PERIOD AS WIDESPREAD THUNDERSTORM ACTIVITY IS
EXPECTED TO DEVELOP ACROSS SOUTHERN NEBRASKA...AND LIKELY AFFECT
KGRI DIRECTLY TO SOME DEGREE. PRIOR TO THUNDERSTORM
DEVELOPMENT...CONFIDENCE IS HIGH IN VFR CONDITIONS...AS THE
DAYTIME AND EARLY EVENING SHOULD ONLY FEATURE PASSING HIGH CLOUDS
GENERALLY AROUND 20K FEET. WITHIN THE PAST HOUR...A FAIRLY SHARP
COLD FRONT HAS PASSED THROUGH KGRI...SWITCHING WINDS TO THE NORTH.
THESE WINDS WILL GRADUALLY TRANSITION TO NORTHEASTERLY DURING THE
DAY...AND FEATURE GUST POTENTIAL TO AROUND 25KT. HAVEN/T GOTTEN
INTO TOO MUCH DETAIL YET WITH THE THUNDERSTORM SITUATION
TONIGHT...BUT HAVE MAINTAINED A VICINITY MENTION STARTING AT
03Z...AND THEN PREVAILING -TSRA FROM 06Z ONWARD. OBVIOUSLY LATER
FORECASTS WILL REFINE TIMING AND ACCOUNT FOR POSSIBLE SUB-VFR
CONDITIONS AS CEILINGS AND VISIBILITY LOWER IN AREAS OF STEADIER
RAIN. A FEW STORMS IN THE AREA TONIGHT COULD ALSO BECOME STRONG
ENOUGH TO PRODUCE HAIL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
556 AM CDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM CDT TUE APR 30 2013
CLEARLY THE MAIN CONCERN DURING THE NEXT 24 HOURS IS THE RISK FOR
POTENTIALLY SEVERAL STRONG TO SEVERE STORMS MAINLY BETWEEN 7 PM
AND 3 AM TONIGHT...AND MAINLY WITHIN THE SOUTHEAST 1/2 OF THE CWA.
OTHERWISE...TODAY MARKS THE TRANSITION DAY BETWEEN THE 80+ DEGREE
WARMTH OF THE PAST FEW DAYS...AND THE UNWELCOME RETURN TO A WINTRY
FEEL TOMORROW.
09Z OBJECTIVE SURFACE ANALYSIS IS HIGHLIGHTED BY THE MUCH-
ADVERTISED COLD FRONT...THAT PER AUTOMATED OBS AND RADAR IMAGERY
IS ALREADY WELL THROUGH AT LEAST THE NORTHWEST 1/3 OF THE
CWA...AND CONTINUES STEADILY PASSING SOUTHEAST. BEHIND THE FRONT
ARE NORTH-NORTHWEST WINDS WITH SUSTAINED SPEEDS GENERALLY 10-20
MPH WITH HIGHER GUSTS. THIS FRONT IS CONNECTED ACROSS THE REGION
BY TWO PRIMARY SURFACE LOW CENTERS...A 991 MILLIBAR NEAR THE
SD/ND/MN BORDER...AND A 996MB ONE ALONG THE KS/CO BORDER. AHEAD OF
THE FRONT...STEADY SOUTH-SOUTHWEST BREEZES 10-20 MPH HAVE BEEN THE
NORM THROUGH THE NIGHT...PROMOTING VERY MILD READINGS MAINLY IN
THE 60S. ALTHOUGH TEMPS ARE FALLING OFF SOMEWHAT BEHIND THE
BOUNDARY...A GOOD CHUNK OF THE CWA SHOULD MAKE IT THROUGH 8AM
WITHOUT DROPPING BELOW THE 55-60 RANGE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A LARGE SCALE TROUGH
AND ASSOCIATED UPPER JET STREAK CENTERED OVER THE NORTHERN
PLAINS/ROCKIES...WITH SEVERAL EMBEDDED SHORTWAVE TROUGHS...THE
MOST VIGOROUS OF WHICH IS SWINGING ALONG THE SD/CANADA BORDER.
FOR THE 7AM-7PM DAYTIME PERIOD...THE VAST MAJORITY...IF NOT THE
ENTIRE CWA SHOULD REMAIN THUNDERSTORM/RAIN FREE...AND ONLY HAVE A
SLIGHT CHANCE OF STORMS AFTER 5 PM IN FAR SOUTHEAST ZONES MAINLY
SOUTHEAST OF A HEBRON-PLAINVILLE LINE. ALOFT...BROAD WEST-
SOUTHWEST FLOW WILL PERSIST OVER THE CENTRAL PLAINS...AS THE
VIGOROUS VORT MAX OVER SD SWINGS NORTHEAST INTO CANADA...WHILE
ADDITIONAL PIECES OF ENERGY SLIDE SOUTHEAST OUT OF THE NORTHWEST
CONUS TOWARD THE CENTRAL ROCKIES...HELPING TO SLOWLY DEEPEN THE
DEVELOPING POSITIVELY TILTED LARGE SCALE TROUGH. AT THE
SURFACE...THE COLD FRONT WILL CONTINUE MAKING STEADY PROGRESS
SOUTHWARD ACROSS THE CWA TODAY...ALTHOUGH IT WILL SLOW AND
ESSENTIALLY STALL OUT AS IT REACHES FAR SOUTHEAST COUNTIES...AS IT
IS COUNTER-ACTED BY A STRENGTHENING WARM FRONT/INVERTED TROUGH
AXIS EXTENDING NORTHEAST FROM A DEEPENING SURFACE LOW NEAR THE
CO/OK/KS/TX BORDER AREA. FOR THE MAJORITY OF THE CWA THAT GETS
BEHIND THE COLD FRONT TODAY...BREEZES WILL AVERAGE AT LEAST 15-20
MPH WITH HIGHER GUSTS...AS THE WIND DIRECTION GRADUALLY SHIFTS
FROM NORTHERLY TO NORTHEASTERLY. TEMPERATURE-WISE...DESPITE
PASSING HIGH CLOUDS...ITS NOW LOOKING LIKE THERE WILL BE ENOUGH
SUNSHINE...AND ALSO WEAK ENOUGH COLD AIR ADVECTION TO ALLOW TEMPS
TO CLIMB HIGHER THAN PREVIOUSLY FORECAST...AND BASED ON A BLEND OF
VARIOUS MODELS/GUIDANCE HAVE RAISED HIGHS ROUGHLY 5 DEGREES ALL
AREAS...NOW AIMING FOR MID 60S NORTHWEST...NEAR 70 CENTRAL...AND
LOW 80S FAR SOUTHEAST. IF THE RAP MODEL IS ONTO SOMETHING...IT MAY
BE EVEN WARMER YET...BUT HAVE LARGELY DISCOUNTED IT FOR NOW. AS
FOR PRE-7PM STORM CHANCES...THEY ARE LOOKING FAIRLY SLIM DESPITE
THE LATEST NAM BUILDING 1000+ J/KG OF 0-1MLCAPE IN FAR SOUTHEAST
ZONES LATE THIS AFTERNOON. FORECAST SOUNDINGS SHOW A PRETTY
FORMIDABLE CAP TO SURFACE-BASED CONVECTION OWING TO WARM 700MB
TEMPS IN AN ELEVATED MIXED LAYER. PER REFLECTIVITY FORECAST FROM
THE 00Z 4KM WRF-NMM AND ALSO THE 09Z RAP...THAYER AND MITCHELL
COUNTIES WOULD BEAR THE MOST WATCHING FOR POSSIBLE STORM
DEVELOPMENT...WHICH COULD BECOME SEVERE QUICKLY SHOULD IT FORM.
ALTHOUGH A BRIEF NEAR-SURFACE BASED SUPERCELL CANNOT BE RULED
OUT...IT WOULD LIKELY TAKE ON A SOMEWHAT LINEAR TENDENCY PRETTY
QUICKLY WITH FLOW ALOFT PARALLEL TO THE LOW LEVEL FRONTAL ZONE.
TURNING TO THE 7PM-7AM TONIGHT PERIOD...CONFIDENCE IS CONSIDERABLY
HIGHER IN WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT...ESPECIALLY
AFTER SUNSET...AND POPS HAVE BEEN BUMPED UP INTO THE 80-90 PERCENT
RANGE FOR MUCH OF THE NIGHT. ALOFT...SHORTWAVE ENERGY WILL
TRANSLATE INTO THE PLAINS FROM THE WEST AS THE PARENT LONGWAVE
TROUGH SETS UP ALONG AN AXIS FROM ND TO THE CENTRAL ROCKIES BY
SUNRISE WEDNESDAY MORNING. WITHIN THE ENTRANCE REGION OF A DAKOTAS
UPPER JET STREAK...LOW-MID LEVEL SOUTHERLY WINDS SPEEDS/RESULTANT
MOISTURE CONVERGENCE WILL RAMP UP MARKEDLY AROUND/AFTER
SUNSET INTO THE FRONTAL ZONE...WITH MOISTURE TRANSPORT SURGING
INTO THE CWA EVIDENT AT BOTH 850 AND 700MB. VARIOUS MODEL
QPF/REFLECTIVITY PROGS SUCH AS FROM THE NAM AND 4KM WRF-NMM AGREE
ON THE SCENARIO OF A RAPID INCREASE IN THUNDERSTORM DEVELOPMENT
THIS EVENING ACROSS MOST IF NOT ALL OF THE CWA...BUT ESPECIALLY
THE SOUTHEAST 1/2. THIS SHOULD BE A FAIRLY CLASSIC SETUP FOR AT
LEAST MARGINALLY SEVERE HAIL AROUND QUARTER SIZE OR SLIGHTLY
LARGER...WITH A CONSENSUS OF THE LATEST NAM/GFS SUGGESTING AT
LEAST 500-1500 J/KG OF MUCAPE IN THE 850-700MB LAYER THROUGH
06Z...IN THE PRESENCE OF DEEP LAYER 0-6KM SHEAR OF GENERALLY 40-60
KT. THIS COULD YIELD AT LEAST A HANDFUL OF ELEVATED SUPERCELL
STRUCTURES TRAINING WITHIN THE SAME GENERAL CORRIDOR...NOT ALL
THAT UNLIKE THE EVENT IN EARLY APRIL THAT AFFECTED MUCH OF THE NEB
CWA. ALTHOUGH A STRONG STORM IS POSSIBLE ALMOST ANYWHERE...THE
GREATEST THREAT FOR LARGE HAIL AND POSSIBLY SEVERE WIND GUSTS
SHOULD RESIDE GENERALLY SOUTH OF AN ELWOOD-OSCEOLA LINE INCLUDING
KS COUNTIES. GRADUALLY DECREASING INSTABILITY SHOULD RESULT IN A
DECREASING SEVERE THREAT BY AROUND 3 AM OR SO...BUT NOT
NECESSARILY SO. SOME PLACES COULD ALSO PICK UP HEALTHY RAINFALL
AMOUNTS OF 1-2+ INCHES...BUT NOT FORESEEING MUCH OF AN ORGANIZED
FLOODING THREAT GIVEN THE RECENT WARM...DRY STRETCH. ALL OF THIS
WILL BE TAKING PLACE IN THE PRESENCE OF STEADY LOW LEVEL COLD AIR
ADVECTION...MARKED BY NORTH-NORTHEAST WINDS OF AT LEAST 20 MPH AND
POSSIBLY CLOSER TO SUSTAINED 30 MPH AT TIMES EVEN OUTSIDE STORM
ACTIVITY. BY SUNRISE WEDNESDAY MORNING...HAVE LOW TEMPS AIMED FROM
THE MID 30S IN NORTHWEST COUNTIES...TO LOW-MID 40S SOUTHEAST. ITS
NOT COMPLETELY OUT OF THE QUESTION THAT SOME SNOW COULD START
MIXING IN WITH RAIN BETWEEN 09Z-12Z...IN FAR NORTHWEST ZONES...BUT
WOULD EXPECT LITTLE IF ANY ACCUMULATION BEFORE SUNRISE...AND EVEN
THEN ONLY IN THE VALLEY/WESTERN DAWSON COUNTY AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 545 AM CDT TUE APR 30 2013
BIGGEST CHALLENGE WILL BE DETERMINING TIMING OF CHANGEOVER TO SNOW
WEDNESDAY AND DETERMINING SNOW AMOUNTS THROUGH WEDNESDAY NIGHT.
WE KICK OFF WEDNESDAY WITH A HIGHLY AMPLIFIED UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN WEST THAT WILL CONTINUE TO AMPLIFY AND HEAD
TOWARD THE CENTRAL PLAINS. PLENTY OF COLD AIR ADVECTION WILL BE
UNDERWAY...BUT ELEVATED CONVECTION COULD STILL BE OCCURRING DURING
THE EARLY MORNING ON WEDNESDAY IN OUR SOUTHEAST. PROBABLY NOT ENOUGH
INSTABILITY FOR SEVERE WEATHER ANYMORE. ALSO...TEMPERATURES WILL NOT
GO ANYWHERE ON WEDNESDAY WITH THE STRONG COLD AIR ADVECTION...SO
TEMPERATURES WILL BE STEADY OR FALLING DURING THE DAY WITH MIX OF
SNOW/SNOW WORKING IN TO THE SOUTHEAST DURING THE DAY. WIND WILL BE
QUITE PERSISTENT FROM THE NORTH...ESPECIALLY TO THE SOUTH WITH STRONG
HEIGHT RISES. WE COULD BE PUSHING WIND ADVISORY OVER NORTH CENTRAL
KANSAS.
LOOKS A LITTLE TRICKY FOR TIMING OF SWITCHING OVER TO SNOW...AND
TOWARD A MIDDLE OF THE ROAD APPROACH AMONG MODEL
SOLUTIONS...CONSIDERING TIMING AND QPF AMOUNTS. WE COULD PICK UP ONE
TO THREE INCHES...BUT MOST OF THIS WOULD BE ON GRASSY
SURFACES...CONSIDERING THAT THIS WILL BE IN THE MONTH OF MAY.
ALSO...THE NAM INDICATES A POSSIBLE LOSS OF SATURATION IN THE DENDRITIC
GROWTH ZONE LATE AFTERNOON AND EVENING WEDNESDAY...WHICH COULD GIVE
US SOME DRIZZLE/FREEZING DRIZZLE FOR A SHORT PERIOD. ALSO...SLEET
MIGHT NOT BE OUT OF THE QUESTION ACCORDING TO SOME MODEL
SUGGESTIONS...BUT I WILL LEAVE BOTH OUT FOR NOW...AS IT DOES NOT
LOOK THAT LIKELY FOR MUCH SLEET WITH SUCH STRONG COLD AIR ADVECTION
AND THE LACK OF SATURATION IN THE DENDRITIC GROWTH ZONE IS VERY
DICEY.
WE COULD STILL HAVE SOME LEFTOVER SNOW IN THE SOUTH/EAST ON THURSDAY
MORNING AS THE TROUGH AXIS WILL NOT PASS TO THE EAST OF THE CWA
UNTIL AT LEAST AFTERNOON.
MODELS THEN CLOSE OFF A LOW WITHIN THE TROUGH BY THURSDAY NIGHT AND
TO BE HONEST...IT IS A FREE FOR ALL FRIDAY THROUGH THE REST OF THE
LONG TERM FORECAST AS THERE IS ABSOLUTELY NO AGREEMENT AMONG MODELS
OF WHAT HAPPENS WITH THE UPPER LOW. ENSEMBLES ARE OUT OF PHASE AS
WELL. STAYING WITH CONTINUITY HERE...BUT CONFIDENCE IS NOT HIGH WITH
THE LATEST FORECASTS FROM MODELS. WE CAN ONLY HOPE FOR SOME SORT OF
AGREEMENT DEVELOPING IN THE NEAR FUTURE. THERE IS GREAT POTENTIAL
FOR BIG BUSTS FOR TEMPERATURE FORECASTS...ESPECIALLY HIGH
TEMPERATURES...AND WE COULD VERY WELL END UP MUCH COOLER THAN
CURRENTLY ADVERTISED.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 100 AM CDT TUE APR 30 2013
VFR CEILING/VISIBILITY ARE CURRENTLY FORECAST THROUGH THE NEXT 24
HOURS...WITH MAINLY JUST PASSING HIGH LEVEL CLOUDS UP AROUND 20K
FEET. HOWEVER...THERE WILL BE INCREASINGLY ACTIVE WEATHER...MAINLY IN
THE FORM OF A SHARP COLD FRONTAL PASSAGE...AND ALSO INCREASING
CHANCES FOR THUNDERSTORMS MAINLY DURING THE FINAL 3 HOURS OF THE
PERIOD TUESDAY NIGHT. STARTING OFF WITH THE VERY SHORT
TERM...SOUTHERLY BREEZES WILL TRANSITION TO WESTERLY THROUGH THE
REST OF THE NIGHT...BEFORE AN ABRUPT SWITCH TO NORTH-NORTHWEST
WINDS ARRIVES AROUND 12Z...WITH GUST POTENTIAL TO AT LEAST 25KT.
PRIOR TO COLD FRONTAL PASSAGE...HAVE INCLUDED A 3-HOUR MENTION OF
LOW LEVEL WIND SHEAR FROM 09Z-12Z AS WINDS ACCELERATE TO AROUND
50KT OUT OF THE SOUTH-SOUTHWEST UP TO AROUND 1500 FT AGL.
NORTHERLY BREEZES WILL REMAIN STEADY THROUGH THE DAY AND INTO THE
EVENING...AND BECOME MORE NORTHEASTERLY WITH TIME. SOMETIME AFTER
SUNSET...A FAIRLY WIDESPREAD AREA OF THUNDERSTORMS IS EXPECTED TO
BLOSSOM ACROSS SOUTHERN NEBRASKA...SOME OF WHICH COULD POTENTIALLY
BECOME STRONG WITH HAIL POTENTIAL. FOR NOW...WILL INTRODUCE A
VICINITY THUNDERSTORM MENTION THROUGH THE FINAL 3 HOURS...WITH
CEILINGS LOWERING TOWARD LOWER-END VFR LEVELS...ALTHOUGH OBVIOUSLY
ANY STORMS DIRECTLY IMPACTING KGRI COULD RESULT IN QUICKLY
DETERIORATING CONDITIONS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1152 PM CDT MON APR 29 2013
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
A FEW CELLS TRIED TO GET GOING...HOWEVER LOOKS LIKE THE TAF SITES
SHOULD REMAIN DRY OVERNIGHT...SO HAVE NOT MENTIONED ANY CIGS BLO
FL100 UNTIL TUESDAY EVENING. LOW LEVEL WIND SHEAR INCLUDED
THROUGH 12Z AT KOMA AND KLNK. SURFACE WINDS SHOULD BE FROM THE
SOUTH OR SOUTHWEST AT 10 TO 15KTS AHEAD OF THE FRONT...WITH A
FRONTAL PASSAGE AT KOFK 10-12Z AND CLOSER TO 18Z AT KOMA AND KLNK.
NORTH WINDS WILL PICK UP AROUND 15KTS WITH HIGHER GUSTS BEHIND THE
FRONT. SHOWERS AND THUNDERSTORMS MAY DEVELOP LATE IN THE AFTERNOON
NEAR KLNK AND KOMA...BUT LEFT OUT UNTIL THE EVENING FOR NOW.
ZAPOTOCNY
&&
.PREV DISCUSSION... /ISSUED 903 PM CDT MON APR 29 2013/
UPDATE...
MAIN FORECAST CONCERN TONIGHT WILL BE CONVECTIVE POTENTIAL...AND
ADJUSTED CLOUDS...WINDS...AND DEWPOINTS TOO.
DISCUSSION...
THE WEAK H5 SHORTWAVE MOVING ACROSS THE AREA APPEARS TO HAVE
TOUCHED OFF SOME ISOLATED THUNDERSTORMS IN IOWA AND NOW WILL BE
WATCHING TO SEE HOW THUNDERSTORMS WILL DEVELOP AS THE LOW LEVEL
JET INCREASES. SEVERAL OF THE SHORT RANGE MODELS DEVELOPED
CONVECTION IN SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALONG A WEAK
BOUNDARY AS DEEPER MOISTURE IS DRAWN NORTHWARD WITH THE INCREASING
LLJ. THE LATEST RAP AND 00Z NAM...ARE NOW MAINLY DRY THIS
EVENING. LEFT IN THE EVENING CHANCE FOR THUNDERSTORMS...BUT THINK
WITH VEERING H85 JET...ANYTHING THAT FORMS WILL QUICKLY SHIFT
NORTHEAST.
ZAPOTOCNY
PREV DISCUSSION... /ISSUED 253 PM CDT MON APR 29 2013/
SHORT TERM...TONIGHT THROUGH THURSDAY.
SURFACE COLD FRONT THAT HAD MOVED INTO SOUTHEAST NEBRASKA
OVERNIGHT HAD PRETTY MUCH WASHED OUT BY 19Z WITH SOUTHERLY WINDS
NOTED ACROSS THE AREA. STILL SOME CHANCE OF SHOWERS AND
THUNDERSTORMS FOR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA THIS
EVENING AS A MID LEVEL WAVE OVER WESTERN NEBRASKA MOVES EAST WITH
BOTH THE GFS AND NAM SHOWING A POCKET OF ELEVATED INSTABILITY OVER
THAT AREA DURING THIS TIME BEFORE MOVING OFF TO THE EAST AFTER
06Z.
MODELS STILL SHOW SIMILAR TIMING FOR THE COLD FRONT JUST COMING
INTO THE NORTHERN PLAINS THIS AFTERNOON REACHING THE NORTHWEST
PORTION OF THE CWA BY 12Z TUESDAY...THEN SOUTHEAST CORNER OF
NEBRASKA BY LATE TUESDAY AFTERNOON. LITTLE CHANGE TO CURRENT
TREND OF INCREASING POPS STARTING TUESDAY AFTERNOON AND EXTENDING
INTO WEDNESDAY NIGHT AS THE SURFACE FRONT DROPS SLOWLY SOUTH AND
UPPER WAVE DIGS INTO THE PLAINS REGION. EASTERN PARTS OF THE AREA
STILL LOOK TO HAVE A CONTINUING CHANCE OF SHOWERS ON THURSDAY AS
CUTOFF LOW DEVELOPS IN VICINITY OF EASTERN KANSAS. TEMPERATURES
ALSO CONTINUE TO TREND BELOW NORMAL AS THE COLD AIR ASSOCIATED
WITH THE UPPER SYSTEM LINGERS OVER THE AREA. SOME SNOW POSSIBLE
WEDNESDAY NIGHT INTO EARLY THURSDAY FOR MUCH OF THE AREA HOWEVER
LITTLE ACCUMULATION EXPECTED AT THIS TIME.
LONG TERM...THURSDAY NIGHT THROUGH MONDAY.
PLACEMENT AND MOVEMENT OF THE CLOSED LOW STILL LOOKS TO BE THE
MAIN PROBLEM IN THE EXTENDED PERIOD. 12Z ECMWF APPEARS TO BE MORE
CONSISTENT WITH PREVIOUS MODEL RUNS WHILE GFS NOW TAKES THE
SYSTEM FURTHER SOUTH. SOME THREAT OF PRECIP INTO THE WEEKEND YET
WITH POTENTIAL FOR RAIN OR SNOW SHOWERS DEPENDING ON ACTUAL TRACK
OF THE SYSTEM.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
209 PM EDT TUE APR 30 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL GENERATE A FEW ISOLATED SHOWERS
AND CLOUDINESS THIS AFTERNOON. OTHERWISE...HIGH PRESSURE
ANCHORED OFF THE NEW ENGLAND COAST WILL REMAIN IN PLACE FOR THE REST
OF THE WEEK AND PROVIDE US WITH MORE SUNSHINE AND WELL ABOVE AVERAGE
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE REMAINS CENTERED OFF THE NEW ENGLAND COAST WITH SURFACE
RIDGING EXTENDED WEST ACROSS NEW YORK STATE. WELL TO THE WEST LOW
PRESSURE IS CENTERED OVER WESTERN ONTARIO CANADA WITH A COLD FRONT
EXTENDED SOUTH INTO THE CENTRAL PLAINS. A THUNDERSTORM COMPLEX TO
OUR WEST HAS SIGNIFICANTLY WEAKENED ACROSS MICHIGAN WITH INFRARED
SATELLITE IMAGERY SHOWING WARMING CLOUD TOPS. SHORT TERM MODEL
GUIDANCE INCLUDING THE 15Z HRRR AND 09Z SREF SHOW THIS COMPLEX
CONTINUING TO WEAKEN THROUGH THE AFTERNOON AS IT MOVES TOWARD A
BUILDING UPPER LEVEL RIDGE AND ASSOCIATED DOWNWARD MOTION OVER THE
EASTERN STATES. WE ARE NOT EXPECTING ANY IMPACT FROM THIS SYSTEM TO
OUR FORECAST AREA TODAY. THROUGH THE AFTERNOON EXPECT JUST AN
ISOLATED SHOWER EAST OF LAKE ONTARIO WHERE AN UPPER LEVEL SHORT WAVE
MAY STILL FORCE THIS. A GRADUAL WEST TO EAST DECREASE IN CLOUDS
ACROSS OUR AREA. THE INCREASE IN SUNSHINE FROM YESTERDAY WILL HELP
TO BOOST TODAYS TEMPS INTO THE LOWER 70S ALONG THE LAKE PLAINS.
OTHERWISE...EXPECT TEMPERATURES TO RANGE THROUGH THE 60S.
TONIGHT...THE SURFACE RIDGE WILL REMAIN IN PLACE WHILE THE LOW TO
OUR WEST LIFTS NORTH TO JAMES BAY. THE UPPER LEVEL RIDGE MUCH OF THE
EAST COAST IS FORECAST TO BUILD FURTHER WEST ACROSS THE OHIO VALLEY
AND LOWER GREAT LAKES. INCREASING LARGE SCALE SUBSIDENCE ASSOCIATED
WITH THE EXPANDING RIDGE WILL HELP THE CLOUDS TO THIN OUT EVEN
MORE...ALTHOUGH THE MODELS ARE HINTING THAT SOME MID AND HIGH LEVELS
CLOUDS FROM UPSTREAM THUNDERSTORM COMPLEX MAY SPILL ACROSS OUR AREA
DURING THE NIGHT. BEST CHANCE FOR THIS WOULD BE ACROSS LAKE ONTARIO
AND THE EASTERN LAKE ONTARIO REGION. WILL MONITOR THIS SYSTEM
THROUGH THE DAY. MAY HAVE TO INCLUDE A SMALL CHANCE FOR A SHOWER OR
THUNDERSTORM ACROSS LAKE ONTARIO AND TO THE EAST IF SYSTEM HOLDS
TOGETHER A LITTLE BETTER THAN MODELS SHOW. THE MILD SOUTHERLY FLOW
WILL ALSO KEEP AREA TEMPERATURES ABOVE SEASONAL AVERAGES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE PATTERN ACROSS NORTH AMERICA WILL CONTINUE TO AMPLIFY ON
WEDNESDAY AS A TROUGH DIGS THROUGH THE ROCKIES AND NORTHERN HIGH
PLAINS...FORCING STRONG DOWNSTREAM HEIGHT RISES ACROSS THE EASTERN
HALF OF THE NATION. INCREASING SUBSIDENCE AND DRYING BENEATH A
BUILDING UPPER LEVEL RIDGE WILL CONTINUE TO ERODE THE LOW/MID LEVEL
MOISTURE THAT WAS LEFT BEHIND BY THE WEAK TROUGH OF THE PAST FEW
DAYS. THIS WILL BRING INCREASING AMOUNTS OF SUNSHINE FOR WEDNESDAY.
850MB TEMPS RISE TO +9C TO +10C BY AFTERNOON...WHICH WILL SUPPORT
HIGHS IN THE MID TO UPPER 70S AT LOWER ELEVATIONS. THE SOUTH TO
SOUTHEAST SYNOPTIC SCALE WIND SHOULD BE STRONG ENOUGH TO PRECLUDE
LAKE BREEZE FORMATION IN MOST AREAS...WITH A FEW POSSIBLE EXCEPTIONS
NOTED IN MESOSCALE MODEL GUIDANCE. IT APPEARS A LOCAL LAKE BREEZE
MAY DEVELOP ALONG THE SOUTH SHORE OF LAKE ONTARIO MAINLY ACROSS THE
NIAGARA AND ORLEANS COUNTY SHORE WITH COOLER TEMPS THERE. GRADIENT
ONSHORE FLOW WILL ALSO KEEP AREAS FROM STONY POINT TO CAPE VINCENT
IN JEFFERSON COUNTY COOLER.
WEDNESDAY NIGHT HIGH PRESSURE REMAINS PARKED ALONG THE NEW ENGLAND
COAST WITH LIGHT SOUTHERLY RETURN FLOW ACROSS THE LOWER LAKES. THIS
WILL KEEP TEMPS UP INTO THE LOWER 50S ON THE LAKE PLAINS OF WESTERN
NY WITH 40S ELSEWHERE.
ON THURSDAY THE MID/UPPER LEVEL RIDGE REMAINS PARKED DIRECTLY
OVERHEAD PROVIDING ANOTHER DRY DAY WITH A GOOD AMOUNT OF SUNSHINE.
850MB TEMPS AROUND +10C WILL AGAIN SUPPORT MID TO UPPER 70S IN MANY
AREAS. SURFACE HIGH PRESSURE WILL BUILD MORE DIRECTLY OVERHEAD ON
THURSDAY...WHICH MEANS SYNOPTIC SCALE FLOW WILL LIKELY BE TOO LIGHT
TO PREVENT LAKE BREEZE FORMATION. THUS...EXPECT ALL THE LAKESHORES
OF BOTH LAKES TO BE COOLER ON THURSDAY.
HIGH PRESSURE SURFACE AND ALOFT REMAINS IN PLACE THURSDAY NIGHT. A
WEAK BAND OF MID LEVEL MOISTURE PEELING OFF A CUTOFF LOW OFF THE NEW
ENGLAND COAST MAY BRING A LITTLE MORE CLOUD COVER TO CENTRAL NY
OVERNIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN EXCEPTIONAL PERIOD OF DRY AND WARM WEATHER WILL CONTINUE THROUGH
NEXT WEEKEND AS A PAIR OF CUTOFF LOWS DEVELOP OVER THE CENTRAL CONUS
AND WESTERN ATLANTIC...ALLOWING A NEARLY STATIONARY OMEGA BLOCK TO
DEVELOP OVER THE OHIO VALLEY AND EASTERN GREAT LAKES. THIS WILL
CONTINUE TO PROVIDE DRY WEATHER THROUGH THE WEEKEND WITH NOTHING
MORE THAN A FEW PERIODS OF HIGH CLOUD AS WEAK DISTURBANCES CROSS THE
TOP OF THE RIDGE. 850MB TEMPS WILL RUN IN THE +8C TO +10C RANGE
DAILY WHICH WILL SUPPORT HIGHS WELL INTO THE 70S. MOS GUIDANCE
CONTINUES TO LOOK TOO LOW FOR THIS PERIOD...AS IS TYPICALLY THE CASE
HERE DURING PRE-FOLIAGE WARM SPELLS. WITH HIGH PRESSURE NEARLY
OVERHEAD...SYNOPTIC SCALE WINDS WILL BE LIGHT ENOUGH TO ALLOW LOCAL
LAKE BREEZES TO DEVELOP ON MOST DAYS WITH COOLER TEMPS ALONG THE
LAKESHORES.
BY MONDAY THE CLOSED LOW OVER THE MIDWEST WILL BEGIN TO MAKE A
LITTLE PROGRESS EAST...BUT THE CONSENSUS FROM THE NEW 00Z GFS AND
ECMWF RUNS IS TO KEEP IT FAR ENOUGH WEST FOR ANOTHER DRY DAY ON
MONDAY WITH CONTINUED WARMTH.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR CIGS WILL CONTINUE TO DRIFT EAST ACROSS THE REGION AS A MID
LEVEL SHORT WAVE WORKS ACROSS NEW YORK. JUST A FEW ISOLATED RAIN
SHOWERS SHOWING UP ON RADAR. A THUNDERSTORM COMPLEX TO OUR WEST IS
WEAKENING OVER MICHIGAN WITH NO IMPACT EXPECTED AT THE TAF SITES
TODAY. ACROSS THE SOUTHERN TIER KJHW SHOULD IMPROVE FROM MVFR CIGS
TO VFR THIS AFTERNOON.
HIGH PRESSURE OFF THE EAST COAST WILL RESULT IN MAINLY VFR
CONDITIONS ACROSS THE REGION TONIGHT EXCEPT FOR KJHW WHERE SOME MVFR
CIGS MAY REDEVELOP IN THE VALLEYS OF THE SOUTHERN TIER. THERE IS A SMALL
CHANCE THAT SOME LINGERING SHOWER/THUNDERSHOWER ACTIVITY FROM THE
COMPLEX TO OUR WEST MAY HOLD TOGETHER ACROSS LAKE ONTARIO AND MAY
APPROACH KART THIS EVENING BUT LEFT OUR OF THE TAFS AT THIS POINT.
NAM BUFKIT SHOWS A WEAK 30 KNOT 1KFT LLJ WILL MOVE OVER THE AREA
OVERNIGHT WHICH WILL HELP KEEP WINDS FROM SLACKENING MUCH OVERNIGHT.
HIGH PRESSURE WILL CONTINUE VFR WEDNESDAY..
OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR.
&&
.MARINE...
A THUNDERSTORM COMPLEX TO OUR WEST OVER MICHIGAN WILL LIFT NORTH
WITH ITS SOUTHERN PORTION FALLING APART BEFORE REACHING EASTERN LAKE
ERIE. SOME LINGERING SHOWERS CLOSER TO THE CENTER OF THIS SYSTEM MAY
BRUSH THE NORTHERN HALF OF LAKE ONTARIO LATER THIS EVENING.
OTHERWISE...HIGH PRESSURE ANCHORED OFF THE NEW ENGLAND COAST WILL
REMAIN NEARLY STATIONARY THROUGH THE WEEK. THIS WILL KEEP THE LOWER
LAKES IN A A PERSISTENT LIGHT TO MODEST SOUTHEASTERLY FLOW THAT WILL
RESULT IN MINIMAL WAVES ALONG THE NEARSHORES OF BOTH LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JM/SMITH
NEAR TERM...SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1016 AM EDT TUE APR 30 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL GENERATE A FEW SHOWERS THIS
MORNING...BEFORE SOME SUNSHINE RETURNS DURING THE AFTERNOON.
OTHERWISE...HIGH PRESSURE ANCHORED OFF THE NEW ENGLAND COAST WILL
REMAIN IN PLACE FOR THE REST OF THE WEEK AND PROVIDE US WITH MORE
SUNSHINE AND WELL ABOVE AVERAGE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE REMAINS ANCHORED JUST OFF THE NEW ENGLAND COAST WITH
SURFACE RIDGING EXTENDED WEST ACROSS NEW YORK STATE THIS MORNING.
WELL TO THE WEST LOW PRESSURE IS CENTERED OVER MINNESOTA WITH A COLD
FRONT EXTENDED SOUTH INTO THE CENTRAL PLAINS. A THUNDERSTORM COMPLEX
IS ALSO FOUND ACROSS MICHIGAN FUELED BY DEEP MOISTURE AND FORCED BY
A 50 KNOT LOW LEVEL JET OUT AHEAD OF THE MINNESOTA LOW. FOR OUR
WEATHER TODAY WE HAVE A MOIST SOUTHERLY FLOW WHICH IS GENERATING
WIDESPREAD CLOUDINESS WITH KBUF/KTYX RADARS SHOWING WEAKENING TREND
TO SCATTERED RAIN SHOWERS FOCUSED MAINLY ACROSS THE FINGER LAKES
LATE THIS MORNING.
THESE SHOWERS FORMED AHEAD OF A WELL DEFINED MID LEVEL SHORT
WAVE TROUGH THAT IS SHIFTING ACROSS WESTERN NEW YORK. THE MODELS
GENERALLY AGREE THAT THIS IMPULSE WILL CROSS OUR CWA THROUGH THE
EARLY AFTERNOON...THEN DROP INTO SOUTHEAST NY AND EASTERN PA BY
EARLY EVENING. WILL MAINTAIN CHANCE OF SHOWERS THIS MORNING FOLLOWED
BY A DECREASING TREND FROM WEST TO EAST DURING THE AFTERNOON.
AS FAR AS THE THUNDERSTORM COMPLEX OVER MICHIGAN...SHORT TERM MODEL
GUIDANCE INCLUDING THE 12Z HRRR AND 03Z SREF SHOW THIS COMPLEX
LIFTING TO THE NORTHEAST WITHING THE SOUTHWESTERLY FLOW ALOFT AND
FALLING APART ALONG ITS SOUTHERN EDGE THROUGH THE AFTERNOON AS IT MOVES
TOWARD A BUILDING UPPER LEVEL RIDGE AND ASSOCIATED DOWNWARD MOTION
OVER THE EASTERN STATES. BASED ON THIS WE ARE NOT EXPECTING ANY
IMPACT FROM THIS SYSTEM TO OUR FORECAST AREA TODAY. THROUGH THE AFTERNOON
EXPECT A GRADUAL WEST TO EAST DECREASE IN CLOUDS ACROSS OUR AREA.
THE ANTICIPATED INCREASE IN SUNSHINE WILL HELP TO BOOST INTO THE
LOWER 70S ALONG THE LAKE PLAINS. OTHERWISE...EXPECT TEMPERATURES TO
RANGE THROUGH THE 60S.
TONIGHT...THE SURFACE RIDGE WILL REMAIN IN PLACE WHILE THE MINNESOTA
LOW LIFTS NORTH TO JAMES BAY. THE UPPER LEVEL RIDGE MUCH OF THE EAST
COAST IS FORECAST TO BUILD FURTHER WEST ACROSS THE OHIO VALLEY AND
LOWER GREAT LAKES. INCREASING LARGE SCALE SUBSIDENCE ASSOCIATED WITH
THE EXPANDING RIDGE WILL HELP THE CLOUDS TO THIN OUT EVEN
MORE...ALTHOUGH THE MODELS ARE HINTING THAT SOME MID AND HIGH LEVELS
CLOUDS FROM UPSTREAM THUNDERSTORM COMPLEX MAY SPILL ACROSS OUR AREA
DURING THE NIGHT. BEST CHANCE FOR THIS WOULD BE ACROSS LAKE ONTARIO
AND THE EASTERN LAKE ONTARIO REGION. WILL MONITOR THIS SYSTEM
THROUGH THE DAY. MAY HAVE TO INCLUDE A SMALL CHANCE FOR A SHOWER OR
THUNDERSTORM ACROSS LAKE ONTARIO AND TO THE EAST IF SYSTEM HOLDS
TOGETHER A LITTLE BETTER THAN MODELS SHOW. THE MILD SOUTHERLY FLOW
WILL ALSO KEEP AREA TEMPERATURES ABOVE SEASONAL AVERAGES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE PATTERN ACROSS NORTH AMERICA WILL CONTINUE TO AMPLIFY ON
WEDNESDAY AS A TROUGH DIGS THROUGH THE ROCKIES AND NORTHERN HIGH
PLAINS...FORCING STRONG DOWNSTREAM HEIGHT RISES ACROSS THE EASTERN
HALF OF THE NATION. INCREASING SUBSIDENCE AND DRYING BENEATH A
BUILDING UPPER LEVEL RIDGE WILL CONTINUE TO ERODE THE LOW/MID LEVEL
MOISTURE THAT WAS LEFT BEHIND BY THE WEAK TROUGH OF THE PAST FEW
DAYS. THIS WILL BRING INCREASING AMOUNTS OF SUNSHINE FOR WEDNESDAY.
850MB TEMPS RISE TO +9C TO +10C BY AFTERNOON...WHICH WILL SUPPORT
HIGHS IN THE MID TO UPPER 70S AT LOWER ELEVATIONS. THE SOUTH TO
SOUTHEAST SYNOPTIC SCALE WIND SHOULD BE STRONG ENOUGH TO PRECLUDE
LAKE BREEZE FORMATION IN MOST AREAS...WITH A FEW POSSIBLE EXCEPTIONS
NOTED IN MESOSCALE MODEL GUIDANCE. IT APPEARS A LOCAL LAKE BREEZE
MAY DEVELOP ALONG THE SOUTH SHORE OF LAKE ONTARIO MAINLY ACROSS THE
NIAGARA AND ORLEANS COUNTY SHORE WITH COOLER TEMPS THERE. GRADIENT
ONSHORE FLOW WILL ALSO KEEP AREAS FROM STONY POINT TO CAPE VINCENT
IN JEFFERSON COUNTY COOLER.
WEDNESDAY NIGHT HIGH PRESSURE REMAINS PARKED ALONG THE NEW ENGLAND
COAST WITH LIGHT SOUTHERLY RETURN FLOW ACROSS THE LOWER LAKES. THIS
WILL KEEP TEMPS UP INTO THE LOWER 50S ON THE LAKE PLAINS OF WESTERN
NY WITH 40S ELSEWHERE.
ON THURSDAY THE MID/UPPER LEVEL RIDGE REMAINS PARKED DIRECTLY
OVERHEAD PROVIDING ANOTHER DRY DAY WITH A GOOD AMOUNT OF SUNSHINE.
850MB TEMPS AROUND +10C WILL AGAIN SUPPORT MID TO UPPER 70S IN MANY
AREAS. SURFACE HIGH PRESSURE WILL BUILD MORE DIRECTLY OVERHEAD ON
THURSDAY...WHICH MEANS SYNOPTIC SCALE FLOW WILL LIKELY BE TOO LIGHT
TO PREVENT LAKE BREEZE FORMATION. THUS...EXPECT ALL THE LAKESHORES
OF BOTH LAKES TO BE COOLER ON THURSDAY.
HIGH PRESSURE SURFACE AND ALOFT REMAINS IN PLACE THURSDAY NIGHT. A
WEAK BAND OF MID LEVEL MOISTURE PEELING OFF A CUTOFF LOW OFF THE NEW
ENGLAND COAST MAY BRING A LITTLE MORE CLOUD COVER TO CENTRAL NY
OVERNIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN EXCEPTIONAL PERIOD OF DRY AND WARM WEATHER WILL CONTINUE THROUGH
NEXT WEEKEND AS A PAIR OF CUTOFF LOWS DEVELOP OVER THE CENTRAL CONUS
AND WESTERN ATLANTIC...ALLOWING A NEARLY STATIONARY OMEGA BLOCK TO
DEVELOP OVER THE OHIO VALLEY AND EASTERN GREAT LAKES. THIS WILL
CONTINUE TO PROVIDE DRY WEATHER THROUGH THE WEEKEND WITH NOTHING
MORE THAN A FEW PERIODS OF HIGH CLOUD AS WEAK DISTURBANCES CROSS THE
TOP OF THE RIDGE. 850MB TEMPS WILL RUN IN THE +8C TO +10C RANGE
DAILY WHICH WILL SUPPORT HIGHS WELL INTO THE 70S. MOS GUIDANCE
CONTINUES TO LOOK TOO LOW FOR THIS PERIOD...AS IS TYPICALLY THE CASE
HERE DURING PRE-FOLIAGE WARM SPELLS. WITH HIGH PRESSURE NEARLY
OVERHEAD...SYNOPTIC SCALE WINDS WILL BE LIGHT ENOUGH TO ALLOW LOCAL
LAKE BREEZES TO DEVELOP ON MOST DAYS WITH COOLER TEMPS ALONG THE
LAKESHORES.
BY MONDAY THE CLOSED LOW OVER THE MIDWEST WILL BEGIN TO MAKE A
LITTLE PROGRESS EAST...BUT THE CONSENSUS FROM THE NEW 00Z GFS AND
ECMWF RUNS IS TO KEEP IT FAR ENOUGH WEST FOR ANOTHER DRY DAY ON
MONDAY WITH CONTINUED WARMTH.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR CIGS WITH SCATTERED SHOWERS WILL CONTINUE TO DRIFT EAST ACROSS
THE REGION THIS MORNING AS A MID LEVEL SHORT WAVE WORKS ACROSS
WESTERN NEW YORK. THUNDERSTORM COMPLEX TO OUR WEST OVER MICHIGAN
WILL LIFT NORTH AND FALL APART ON ITS SOUTHERN EDGE BEFORE REACHING
WESTERN NEW YORK WITH NO IMPACT EXPECTED AT THE TAF SITES TODAY. ACROSS
THE SOUTHERN TIER KJHW WILL IMPROVE FROM MVFR CIGS TO VFR BY THE
AFTERNOON.
HIGH PRESSURE ANCHORED OFF THE EAST COAST WILL RESULT IN MAINLY VFR
CONDITIONS ACROSS THE REGION TONIGHT. THERE IS A SMALL CHANCE THAT
SOME LINGERING SHOWER/THUNDERSHOWER ACTIVITY FROM THE COMPLEX TO OUR
WEST MAY HOLD TOGETHER ACROSS LAKE ONTARIO AND MAY APPROACH KART
THIS EVENING.
OUTLOOK...
WEDNESDAY THROUGH SATURDAY...VFR.
&&
.MARINE...
A THUNDERSTORM COMPLEX TO OUR WEST OVER MICHIGAN WILL LIFT NORTH
WITH ITS SOUTHERN PORTION FALLING APART BEFORE REACHING EASTERN LAKE
ERIE LATER TODAY. SOME LINGERING SHOWERS/THUNDERSHOWERS CLOSER TO
THE CENTER OF THIS SYSTEM MAY BRUSH THE NORTHERN HALF OF LAKE
ONTARIO LATER THIS EVENING. OTHERWISE...HIGH PRESSURE ANCHORED OFF
THE NEW ENGLAND COAST WILL REMAIN NEARLY STATIONARY THROUGH THE
WEEK. THIS WILL KEEP THE LOWER LAKES IN A A PERSISTENT LIGHT TO
MODEST SOUTHEASTERLY FLOW THAT WILL RESULT IN MINIMAL WAVES ALONG
THE NEARSHORES OF BOTH LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP
NEAR TERM...SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
745 PM EDT WED MAY 1 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND DOWN THE EAST COAST THROUGH THE REMAINDER
OF THE WORK WEEK. LOW LEVEL NE FLOW WILL MAINTAIN A MOIST AIR MASS
THROUGH EARLY THURSDAY...AFTERWHICH DRIER AIR WILL OVERSPREAD THE
REGION.
&&
.NEAR TERM /TONIGHT/...
AS OF 312 PM WEDNESDAY...
TONIGHT...925-850MB FLOW VEERS THIS EVENING TO MORE OF A E-SE
DIRECTION. THIS UPSLOPE COMPONENT AND FETCH OFF THE ATLANTIC WILL
MAINTAIN LOW OVERCAST SKIES. ISENTROPIC LIFT IN THE 290-295K LAYER
SHOULD RESULT IN AREAS OF DRIZZLE AND POSSIBLY SOME POCKETS OF LIGHT
RAIN. GFS DEPICTS A DECENT POCKET OF LIFT OVER THE WESTERN PIEDMONT
LATE TONIGHT WHICH WOULD SUPPORT A GREATER CHANCE OF RAIN
OVERNIGHT. HRRR VERIFYING RELATIVELY WELL WITH ISOLATED/SCATTERED
SHOWERS ALONG IMMEDIATE COAST AND SPOTS OF LIGHT PRECIP INLAND. THIS
MODEL SUGGEST BULK OF VERY LIGHT PRECIP DEVELOPING OVER THE PIEDMONT
BY 02-05Z. PLAN TO MAINTAIN MEASURABLE POPS AT 20 PERCENT THOUGH
EXPECT AREAS OF DRIZZLE TO DEVELOP BY LATE EVENING AND CONTINUE INTO
THE OVERNIGHT. MIN TEMPS MID-UPPER 50S. ANY FOG THAT DEVELOPS WILL
BE SPOTTY AS STEADY NE SFC WIND WILL KEEP AIR MASS MIXED.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 312 PM WEDNESDAY...
THURSDAY...CONSIDERABLE CLOUDINESS IN THE MORNING WILL GRADUALLY
BECOME MOSTLY SUNNY/PARTLY CLOUDY ACROSS THE REGION AS AS LOW LEVEL
HIGH PRESSURE DRIFTS SOUTHWEST INTO THE NORTHERN MID ATLANTIC. THE
CLOSER PROXIMITY OF THIS FEATURE TO OUR REGION PLUS ADVECTION OF
DRIER AIR WILL AID TO SLOWLY ERODE THE CLOUD COVER FROM THE EAST
LATE THU AM THROUGH THE AFTERNOON. THE WESTERN-SOUTHERN PIEDMONT
WILL BE THE LAST TO EXPERIENCE PARTIAL CLEARING. BASED ON THIS SKY
TREND...EXPECT WARMER TEMPS EAST VERSUS WEST. MAX TEMPS LOWER 70S
FAR SOUTH-SE TO UPPER 60S W-NW.
THURSDAY NIGHT..RIDGE AT THE SURFACE AND ALOFT WILL RESULT IN FAIR
SKIES. RESIDUAL LOW LEVEL MOISTURE SHOULD ALLOW PATCHES OF FOG TO
DEVELOP. IF SFC WINDS ABLE TO DECOUPLE...MAY SEE WIDESPREAD FOG WITH
POCKETS OF DENSE FOG. COOLER OVERNIGHT TEMPS IN THE UPPER 40S TO THE
LOWER 50S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 250 PM WEDNESDAY...
FRIDAY THROUGH SUNDAY:
MEDIUM RANGE MODELS CONTINUE TO INDICATE AN AMPLIFIED PATTERN FOR
THE START OF THE PERIOD (LATE WEEK INTO THE WEEKEND)... WITH HIGH
PRESSURE ALOFT CENTERED JUST TO THE NORTH OF THE AREA AND SURFACE
HIGH PRESSURE LOCATED TO THE NORTHEAST OF THE REGION WITH CLOSED
LOWS FLANKING THE RIDGE ALOFT TO THE WEST AND EAST (ACROSS THE
CENTRAL CONUS AND WESTERN ATLANTIC). THIS WILL KEEP CENTRAL NC IN
THE CURRENT PATTERN OF A COOL EAST TO NORTHEASTERLY LOW LEVEL
FLOW... WITH PERIODS OF LOW CLOUDS AND POSSIBLE DRIZZLE. HOWEVER...
THINK WE WILL SEE AT LEAST SOME BREAKS IN THE CLOUDS OVER THE
WEEKEND. THUS... EXPECT HIGH TEMPS WILL GENERALLY BE BELOW NORMAL
RANGING FROM THE UPPER 60S TO THE 70S... WITH MORNING LOWS EXPECTED
TO BE NEAR NORMAL. THE COOLEST TEMPS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY WHEN IT APPEARS ANOTHER REINFORCING SURGE OF MOISTURE AND
COOLER TEMPS WILL FILTER INTO THE REGION... ASSOCIATED WITH ANOTHER
DISTURBANCE MOVING THROUGH THE CYCLONIC FLOW AROUND THE WESTERN
ATLANTIC LOW.
SUNDAY NIGHT THROUGH WEDNESDAY:
CONFIDENCE IN THE FORECAST PAST THE UPCOMING WEEKEND GOES DOWN
SIGNIFICANTLY... AS THE MEDIUM RANGE MODEL GUIDANCE IS STRUGGLING
WITH THE EVENTUAL PROGRESSION AND EVOLUTION OF THE CENTRAL CONUS
CLOSED LOW. HAVE STUCK CLOSE TO THE PREVIOUS FORECAST AND WPC AT
THIS TIME... WITH WPC GOING GENERALLY WITH THE 00Z/01ST ECENS MEAN
AS A SYNOPTIC GUIDE. WPC ALSO NOTED THE GFS/GEFS MEANS ARE
INCREASING OUTLIERS TO EVEN THE GEM GLOBAL AND UKMET (WHICH
YESTERDAY WERE MORE CORRELATED WITH THE GFS). NONETHELESS... IT
STILL LOOKS LIKE WE MAY SEE CHANCES FOR SHOWERS INCREASE NEXT WEEK
AS THE RIDGE BEGINS TO BREAK DOWN SOME/SHIFT MORE TO THE EAST OF THE
AREA. THUS... WILL ADVERTISE LOW END CHANCE POPS/SLIGHT CHANCE POPS
ACROSS THE AREA FOR EARLY NEXT WEEK... WITH SLOWLY MODERATING TEMPS.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 745 PM WEDNESDAY...
CLOUD COVER IS WIDESPREAD ACROSS THE CAROLINAS THIS EVENING AS A
MOIST NORTHEASTERLY FLOW CONTINUES. CEILINGS ARE ALREADY AT MVFR
LEVELS AT NEARLY EVERY REPORTING STATION ACROSS CENTRAL NC...AND
CEILINGS WILL ONLY CONTINUE TO LOWER OVERNIGHT...LIKELY REACHING IFR
LEVELS EVERYWHERE BY MIDNIGHT. PATCHES OF LIGHT RAIN OR DRIZZLE CAN
DRIZZLE CAN ALSO BE EXPECTED...WHICH MAY LEAD TO A PERIOD OF LIFR
CONDITIONS. LIFR CONDITIONS APPEAR TO BE MOST LIKELY AT KGSO/KINT.
A SLOW LIFTING OF CEILINGS TO MVFR AND EVENTUALLY VFR CONDITIONS IS
EXPECTED ON THURSDAY...WITH MOST AREAS POTENTIALLY REACHING VFR
BETWEEN 17-21Z.
OUTLOOK...
WHILE HIGH PRESSURE AND NORTHEASTERLY FLOW WILL CONTINUE THIS
WEEKEND...A GENERAL DRYING OF THE AIRMASS IS EXPECTED. THIS WILL
LEAD TO MOSTLY VFR CONDITIONS DURING THE DAY...WITH PERIODS OF
MVFR/IFR CONDITIONS IN THE EARLY MORNING HOURS. THE NEXT CHANCE OF
RAIN AND PROLONGED SUB-VFR CONDITIONS MAY COME MONDAY AS AN UPPER
LEVEL LOW PRESSURE SYSTEM SLOWLY DRIFTS INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
656 AM CDT TUE APR 30 2013
.UPDATE...
ISSUED AT 654 AM CDT TUE APR 30 2013
THE ONLY SIGNIFICANT CHANGE WITH THIS FORECAST UPDATE TO WAS TO
ADJUST FOR THE STRATUS DECK THAT HAS ENTERED WESTERN NORTH DAKOTA
AND WILL CONTINUE TO PUSH EAST THROUGH THE MORNING...MIXING OUT
THROUGH THE AFTERNOON. THE 10 UTC RAP CAPTURES THIS DECK WELL AND
FOLLOWED IT FOR SKY GRIDS THROUGH THE REMAINDER OF THE DAY.
OTHERWISE...NO CHANGES NEEDED OTHER THAN TO BLEND TO TRENDS
THROUGH 11 UTC.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM CDT TUE APR 30 2013
CURRENTLY...A BAND OF SHOWERS ARE MOVING NORTH AND EAST OVER THE
JAMES RIVER VALLEY...NORTHEAST THROUGH THE RED RIVER VALLEY.
WITH IN THIS BAND OF SHOWERS...THERE IS AN AREA OF MODERATE TO
HEAVY RAINFALL...PRODUCING A RADAR ESTIMATED HALF TO AN INCH PER
HOUR. THIS AREA OF MODERATE TO HEAVY PRECIP WILL CONTINUE TO MOVE
NORTHEAST AND OVER THE JAMES RIVER VALLEY THIS MORNING AND
AGGRAVATING EXISTING OVERLAND FLOODING ISSUES. SHORT TERM GUIDANCE
CONTINUES TO PUSH THIS BAND OF SHOWER ACTIVITY NORTHEAST...ENDING
ANY CHANCES FOR PRECIPITATION FOR THE JAMES RIVER VALLEY AROUND
12Z THIS MORNING.
THE MAIN FORECAST HIGHLIGHTS FOR THE SHORT TERM PERIOD INCLUDE
FIRE WEATHER (EXPLAINED BELOW) AND WIND HEADLINES.
AS LOW PRESSURE EXITS TO THE NORTHEAST AND HIGH PRESSURE STARTS TO
BUILD SOUTHEAST FROM SOUTHERN CANADA TODAY...STRONG GUSTY WEST TO
NORTHWEST WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL NORTH
DAKOTA TODAY. THE 00Z NAM/GFS BUFR SOUNDINGS SHOW THE POTENTIAL
FOR MIXING TO BETWEEN 800 AND 750 MB THIS MORNING THROUGH THIS EVENING.
THIS WOULD RESULT IN WINDS AT THIS LEVEL OF 35 TO 50 KTS TO MIX TO
THE SURFACE. THIS WILL ALSO COINCIDE WITH 6-HOUR PRESSURE RISE
MAXIMA OF 9 TO 11 MB THAT IS FORECAST BY THE 00Z GFS TO MOVE OVER
WESTERN AND CENTRAL NORTH DAKOTA BETWEEN 12 AND 00Z. THIS WILL
RESULT IN WINDS THAT WILL BE SUSTAINED OVER 30 MPH...WITH GUSTS TO
NEAR 45 MPH...MEETING ADVISORY CRITERIA. THUS HAVE DECIDED TO
ISSUE A WIND ADVISORY FOR ALL BUT THE NORTHERN TIER OF COUNTIES
THROUGH 00Z. AFTER 00Z...WINDS SHOULD SUBSIDE AS BUFR SOUNDINGS
FORECAST THE DEMISE OF THE MIXED LAYER...DECOUPLING THE SURFACE
AND 800-750MB WINDS.
MEANWHILE...THERE WILL BE A BRIEF PERIOD OF LIGHT MIXED
PRECIPITATION AND SNOW SHOWERS ACROSS THE NORTH THROUGH THIS
EVENING. SNOWFALL ACCUMULATIONS ARE EXPECTED TO BE LIGHT AND LESS
THAN AN INCH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 413 AM CDT TUE APR 30 2013
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE BELOW NORMAL
TEMPERATURES WEDNESDAY THROUGH LATE THIS WEEK...WITH SIGNIFICANT
UNCERTAINTY INTO THE WEEKEND AND EARLY NEXT WEEK.
THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITE IS IN GOOD AGREEMENT
TO BEGIN THE EXTENDED...WITH A CENTRAL CONUS LONGWAVE TROUGH
SUPPORTING WIDESPREAD BELOW NORMAL TEMPERATURES IN THE 40S AND 50S
WEDNESDAY AND THURSDAY. THEREAFTER...THE SPREAD OF SOLUTIONS
QUICKLY WIDENS FRIDAY THROUGH THE REMAINDER OF THE EXTENDED IN
REGARDS TO CUTTING OFF OF THE SOUTHERN STREAM ENERGY AND THE
EVENTUAL PROPAGATION OF THE CLOSED LOW THROUGH THE WEEKEND. THE
POSITIONING OF THIS UPPER LEVEL LOW RANGES FROM NORTHERN MINNESOTA
ON SUNDAY ON THE 00 UTC ECMWF...TO MISSOURI ON THE 00 UTC GFS AND
GEFS MEAN...WITH A RANGE IN BETWEEN. CONFIDENCE IN ANY SOLUTION IS
LOW...WITH SIGNIFICANT IMPACTS TO FORECAST TEMPERATURES AND
PRECIPITATION CHANCES. WITH SUCH LITTLE CONFIDENCE AND WIDELY
RANGING SENSIBLE WEATHER...WILL GO WITH A BLEND FOR NOW AND ALLOW
ADDITIONAL MODEL CYCLES TO RESOLVE A GREATER CONSENSUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY)
ISSUED AT 654 AM AM CDT TUE APR 30 2013
MVFR STRATUS HAS ENTERED WESTERN NORTH DAKOTA AND WILL CONTINUE TO
PUSH EAST THROUGH THE MORNING...BEFORE SLOWLY LIFTING AND
SCATTERING OUT THROUGH THE AFTERNOON. STRONG WEST-NORTHWEST WIND
GUSTS OF 35-40 KTS ARE EXPECTED AT KDIK...KBIS AND KJMS TODAY...WITH
SLIGHTLY WEAKER WINDS FOR THE KISN AND KMOT TERMINALS. SCATTERED
RAIN AND SNOW SHOWERS ARE FORECAST FOR NORTHERN NORTH DAKOTA.
HOWEVER...DUE TO UNCERTAINTY IN IMPACTS TO TERMINALS...WILL ONLY
CODE AS VCSH IN THE KISN AND KMOT TAF.
&&
.FIRE WEATHER...
ISSUED AT 413 AM CDT TUE APR 30 2013
FIRE WEATHER CONCERNS WILL CONTINUE TODAY...ESPECIALLY ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL COUNTIES. THE FIRE DANGER
INDEX IN THESE AREAS WILL BE IN THE VERY HIGH CATEGORY. THIS IS
MAINLY DUE TO STRONG WEST TO NORTHWEST WINDS GUSTING UP TO NEAR 40
TO 45 MPH. FACTORS AGAINST FIRE WEATHER HEADLINES ARE MIN RH
VALUES IN THE 30S...COOLER TEMPERATURES IN THE 50S AND LINGERING
MOISTURE FROM OVERNIGHT RAIN. HOWEVER...IF THE STRONG WEST TO
NORTHWEST WINDS DRY OUT THE FUELS FASTER THAN EXPECTED...THEN
HEADLINES MAY BE NEEDED FOR TUESDAY AFTERNOON. WILL MONITOR THIS
SITUATION FOR ANY DEVELOPMENTS.
&&
.HYDROLOGY...
ISSUED AT 413 AM CDT TUE APR 30 2013
ISSUED A FLOOD ADVISORY FOR STUTSMAN COUNTY THROUGH 330 AM CDT
WEDNESDAY...AS OVERNIGHT RAINFALL COMBINED WITH SNOW MELT FROM THE
WEEKEND MAY LEAD TO FLOODING OF COUNTY AND TOWNSHIP ROADS AND
ADDITIONAL RISES ON FASTER RESPONDING CREEKS AND STREAMS.
OTHERWISE...ACROSS THE SOURIS BASIN...THE DES LACS RIVER AT
FOXHOLM WAS CONTINUING TO FALL...AND IS EXPECTED TO GO BELOW FLOOD
STAGE THIS MORNING. IN GENERAL...ON THE SOURIS RIVER FROM THE
CONFLUENCE WITH THE DES LACS...THROUGH MINOT AND LOGAN...STAGES
ARE STEADY OR FALLING AS THE PEAK OF THE DES LACS FLOWS HAS
PASSED. FROM SAWYER THROUGH WESTHOPE...STAGES ARE EXPECTED TO
CONTINUE TO INCREASE...WITH ADDITIONAL RISES ON THE WINTERING
RIVER AND WILLOW CREEK. THE SOURIS RIVER ABOVE LAKE DARLING WILL
CONTINUE TO RISE THROUGH THIS WEEK FROM RUNOFF BELOW THE CANADIAN
DAMS AND EVENTUAL RESERVOIR RELEASES. FOR THE JAMES BASIN...THE
JAMES RIVER AND PIPESTEM CREEK ABOVE THE RESERVOIRS CONTINUE TO
DEPICT ELEVATED FLOWS...WITH MODERATE FLOODING EXPECTED ON THE
PIPESTEM CREEK NEAR PINGREE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ017>020-031>034-040>045.
WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING
FOR NDZ010>013-021>023-025-035>037-046>048-050-051.
&&
$$
UPDATE...AYD
SHORT TERM...LTH
LONG TERM...AYD
AVIATION...LTH
FIRE WEATHER...LTH
HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
123 PM EDT TUE APR 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL STAY JUST EAST OF THE AREA THROUGH SUNDAY. A LOW
WILL MOVE NORTH INTO ILLINOIS THURSDAY INTO FRIDAY THEN DRIFT WEST
INTO MISSOURI ON THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHOWERS AND THUNDERSTORMS MOVING ACROSS SOUTHEAST MICHIGAN ARE
SHOWING A DIMINISHING TREND AS CLOUD TOPS WARM. STILL EXPECTING THIS
TO PASS NORTH OF TOLEDO BUT DID INCLUDE A 20 PERCENT CHANCE OF A
SHOWER/THUNDERSTORM IN THE LATEST UPDATE. CLOUDS WILL BE OVERCAST
IN EXTREME NW OH AS A THICK MID CLOUD DECK HAS OVERSPREAD THE AREA
BEFORE CLEARING LATE IN THE DAY. ESLEWHERE...A HEALTHY CU DECK HAS
DEVELOPED ACROSS MUCH OF THE AREA WITH PARTLY TO MOSTLY CLOUDY
SKIES. ALTHOUGH THESE WILL START TO SCATTER OUT LATER THIS
AFTERNOON...THIS HAS SLOWED WARMING AND TWEAKED TEMPERATURES DOWN
BY A COUPLE DEGREES MOST AREAS...AND SEVERAL DEGREES IN NW PA.
PREVIOUS DISCUSSION...HIGH PRESSURE AT UPPER LEVEL WILL START TO
BUILD OVER THE AREA TODAY. THIS WILL PROVIDE GENERAL SUBSIDENCE
AND WORK TO SUPPRESS CONVECTION THAT TRIES TO DEVELOP. WILL HAVE
TO WATCH FOR THE POSSIBILITY OF A STRAY SPRINKLE OVER MI DROPPING
ESE TOWARD LAKE ERIE THIS MORNING BEFORE THE RIDGING STARTS TO
BUILD. HEALTHY CONVECTION HAS DEVELOPED IN SW MI LAST HOUR OR TWO
AND LATEST HRRR BRINGS SOME LEFTOVER SHRA FROM THIS ACTIVITY INTO
THE NW THREE COUNTIES AROUND 15Z. HAVE INCREASED POP FOR THE NW
THRU EARLY AFTERNOON TO ALLOW FOR A CHANCE OF SHRA.
A PREDOMINATELY SOUTH FLOW AND THE COMPRESSIONAL WARMING WILL
PUSH HIGHS THIS AFTERNOON WELL INTO THE 70S. HOWEVER...THE
PRESSURE GRADIENT MAY BE WEAK ENOUGH FOR A LAKE BREEZE TO DEVELOP
CLOSE TO THE LAKESHORE SO WILL KEEP TEMPS A LITTLE COOLER ALONG
THE IMMEDIATE LAKE SHORE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
UPPER RIDGING OVER THE AREA SHOULD KEEP CONDITIONS DRY FOR MOST OF
THE AREA TONIGHT THROUGH FRI NIGHT. THE ONLY EXCEPTIONS WILL BE FOR
A POSSIBLE STAY SHRA WED AS GOOD MOISTURE AROUND 850 MB GETS PUSHED
BACK NW OVER THE CWA. WILL CONTINUE TO KEEP POPS BELOW 15% SO NO
PRECIP WILL BE MENTIONED IN FORECAST. THE INVERTED LOW PUSHING NORTH
INTO THE IL/IN AREA THU INTO THU NIGHT COULD PRODUCE SOME ISOLATED
SHRA THAT MAY GET CLOSE TO OUR WESTERN BORDER THU THRU FRI BUT THE
RISK STILL LOOKS LOW ENOUGH TO KEEP POPS BELOW 15%.
THE INVERTED LOW WILL CAUSE WINDS TO BACK TOWARD THE EAST THU INTO
FRI SO WOULD EXPECT HIGH TEMPS TO LOOSE A FEW DEGREES AFTER PEAKING
ON WED. ALSO THE EAST DIRECTION WILL HAVE A MUCH BETTER CHANCE OF
BACKING TO NE FOR THE AFTERNOON NEAR THE LAKE SO TEMPS EVEN COOLER
THERE.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
LONG TERM BEGINS ON SATURDAY WITH THE MODELS SHOWING THE CUTOFF
UPPER LOW OVER THE CENTRAL PLAINS. THE ECMWF REMAINS CONSISTENT
FROM 00Z TO 12Z RUNS WITH THE LOW NEAR KANSAS CITY WHILE THE 00Z GFS
HAS SHIFTED THE LOW SOUTH TO ARKANSAS. BY SUNDAY THE ECMWF TAKES THE
LOW TO IOWA WHILE THE GFS MOVES IT TO MISSOURI. MONDAY THE MODELS
DIVERGE FURTHER WITH THE ECMWF TAKING THE LOW ACROSS THE CENTRAL
GREAT LAKES INTO ONTARIO WHILE THE GFS HAS THE LOW IN SERN MISSOURI
AND SRN IL. WILL CONTINUE WITH PERSISTENCE KEEPING SLIGHT CHANCE
POPS WEST AT FIRST THEN INCREASING TO CHANCE SUNDAY BEFORE SPREADING
CHANCE POPS EAST SUNDAY NIGHT AND MONDAY. TEMPS SEASONAL.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
AS CUMULUS FIELD BUILDS ACROSS THE FORECAST AREA EXPECT AREAS TO
GO IN AND OUT OF MVFR AS CIGS BECOME OCCASIONALLY BROKEN. LOW CLOUDS
WILL BEGIN TO DISSIPATE AFTER SUNSET WITH THE EXCEPTION OF MID TO
HIGH CLOUDS THAT WILL SHEAR DOWNSTREAM OF A DISTURBANCE MOVING
ACROSS LAKE MICHIGAN. A RAIN SHOWER CANNOT BE RULED OUT AT TOLEDO
BETWEEN 18-22Z AS THE TROUGH PIVOTS TO THE NORTHWEST AND PULLS OUT
INTO ONTARIO DURING THE OVERNIGHT. THERE WILL BE SUFFICIENT LOW
LEVEL MOISTURE AT TOL FDY MFD AND YNG TO INITIATE EARLY MORNING MVFR
FOG. ADEQUATE MIXING AND DRIER AIR ALOFT WILL SCOUR OUT ANY FOG
BY MID MORNING.
.OUTLOOK...VFR EXCEPT FOR LOCAL LIGHT FOG/MIST EACH MORNING.
&&
.MARINE...
EXPECTING A FAIRLY STAGNANT WEATHER PATTERN TO DEVELOP ACROSS THE
REGION WITH HIGH PRESSURE TO OUR EAST AND LOW PRESSURE ACROSS THE
NATIONS MID SECTION. THIS WILL KEEP WINDS FROM THE SOUTH TO
SOUTHEAST ON THE LAKE THROUGH THE NEAR AND INTERMEDIATE TERM. NO
HEADLINES EXPECTED THROUGH THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS/KEC
SHORT TERM...ADAMS
LONG TERM...TK
AVIATION...MAYERS
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1248 PM EDT TUE APR 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL STAY JUST EAST OF THE AREA THROUGH SUNDAY. A LOW
WILL MOVE NORTH INTO ILLINOIS THURSDAY INTO FRIDAY THEN DRIFT WEST
INTO MISSOURI ON THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHOWERS AND THUNDERSTORMS MOVING ACROSS SOUTHEAST MICHIGAN ARE
SHOWING A DIMINISHING TREND AS CLOUD TOPS WARM. STILL EXPECTING THIS
TO PASS NORTH OF TOLEDO BUT DID INCLUDE A 20 PERCENT CHANCE OF A
SHOWER/THUNDERSTORM IN THE LATEST UPDATE. CLOUDS WILL BE OVERCAST
IN EXTREME NW OH AS A THICK MID CLOUD DECK HAS OVERSPREAD THE AREA
BEFORE CLEARING LATE IN THE DAY. ESLEWHERE...A HEALTHY CU DECK HAS
DEVELOPED ACROSS MUCH OF THE AREA WITH PARTLY TO MOSTLY CLOUDY
SKIES. ALTHOUGH THESE WILL START TO SCATTER OUT LATER THIS
AFTERNOON...THIS HAS SLOWED WARMING AND TWEAKED TEMPERATURES DOWN
BY A COUPLE DEGREES MOST AREAS...AND SEVERAL DEGREES IN NW PA.
PREVIOUS DISCUSSION...HIGH PRESSURE AT UPPER LEVEL WILL START TO
BUILD OVER THE AREA TODAY. THIS WILL PROVIDE GENERAL SUBSIDENCE
AND WORK TO SUPPRESS CONVECTION THAT TRIES TO DEVELOP. WILL HAVE
TO WATCH FOR THE POSSIBILITY OF A STRAY SPRINKLE OVER MI DROPPING
ESE TOWARD LAKE ERIE THIS MORNING BEFORE THE RIDGING STARTS TO
BUILD. HEALTHY CONVECTION HAS DEVELOPED IN SW MI LAST HOUR OR TWO
AND LATEST HRRR BRINGS SOME LEFTOVER SHRA FROM THIS ACTIVITY INTO
THE NW THREE COUNTIES AROUND 15Z. HAVE INCREASED POP FOR THE NW
THRU EARLY AFTERNOON TO ALLOW FOR A CHANCE OF SHRA.
A PREDOMINATELY SOUTH FLOW AND THE COMPRESSIONAL WARMING WILL
PUSH HIGHS THIS AFTERNOON WELL INTO THE 70S. HOWEVER...THE
PRESSURE GRADIENT MAY BE WEAK ENOUGH FOR A LAKE BREEZE TO DEVELOP
CLOSE TO THE LAKESHORE SO WILL KEEP TEMPS A LITTLE COOLER ALONG
THE IMMEDIATE LAKE SHORE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
UPPER RIDGING OVER THE AREA SHOULD KEEP CONDITIONS DRY FOR MOST OF
THE AREA TONIGHT THROUGH FRI NIGHT. THE ONLY EXCEPTIONS WILL BE FOR
A POSSIBLE STAY SHRA WED AS GOOD MOISTURE AROUND 850 MB GETS PUSHED
BACK NW OVER THE CWA. WILL CONTINUE TO KEEP POPS BELOW 15% SO NO
PRECIP WILL BE MENTIONED IN FORECAST. THE INVERTED LOW PUSHING NORTH
INTO THE IL/IN AREA THU INTO THU NIGHT COULD PRODUCE SOME ISOLATED
SHRA THAT MAY GET CLOSE TO OUR WESTERN BORDER THU THRU FRI BUT THE
RISK STILL LOOKS LOW ENOUGH TO KEEP POPS BELOW 15%.
THE INVERTED LOW WILL CAUSE WINDS TO BACK TOWARD THE EAST THU INTO
FRI SO WOULD EXPECT HIGH TEMPS TO LOOSE A FEW DEGREES AFTER PEAKING
ON WED. ALSO THE EAST DIRECTION WILL HAVE A MUCH BETTER CHANCE OF
BACKING TO NE FOR THE AFTERNOON NEAR THE LAKE SO TEMPS EVEN COOLER
THERE.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
LONG TERM BEGINS ON SATURDAY WITH THE MODELS SHOWING THE CUTOFF
UPPER LOW OVER THE CENTRAL PLAINS. THE ECMWF REMAINS CONSISTENT
FROM 00Z TO 12Z RUNS WITH THE LOW NEAR KANSAS CITY WHILE THE 00Z GFS
HAS SHIFTED THE LOW SOUTH TO ARKANSAS. BY SUNDAY THE ECMWF TAKES THE
LOW TO IOWA WHILE THE GFS MOVES IT TO MISSOURI. MONDAY THE MODELS
DIVERGE FURTHER WITH THE ECMWF TAKING THE LOW ACROSS THE CENTRAL
GREAT LAKES INTO ONTARIO WHILE THE GFS HAS THE LOW IN SERN MISSOURI
AND SRN IL. WILL CONTINUE WITH PERSISTENCE KEEPING SLIGHT CHANCE
POPS WEST AT FIRST THEN INCREASING TO CHANCE SUNDAY BEFORE SPREADING
CHANCE POPS EAST SUNDAY NIGHT AND MONDAY. TEMPS SEASONAL.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
CONDITIONS MVFR/IFR IN EARLY MORNING FOG WITH LOWEST CONDITIONS
EAST AWAY FROM THE LAKE. MORNING FOG WILL LIFT QUICKLY WITH
CONDITIONS BECOMING VFR BY 14Z. AFTER DAYBREAK VFR CONDITIONS
WILL PERSIST THROUGH THE DAY AND INTO THE EVENING. EXPECTING THE
DEVELOPMENT OF SOME FOG AGAIN TONIGHT.
.OUTLOOK...VFR EXCEPT FOR LOCAL LIGHT FOG/MIST EACH MORNING.
&&
.MARINE...
EXPECTING A FAIRLY STAGNANT WEATHER PATTERN TO DEVELOP ACROSS THE
REGION WITH HIGH PRESSURE TO OUR EAST AND LOW PRESSURE ACROSS THE
NATIONS MID SECTION. THIS WILL KEEP WINDS FROM THE SOUTH TO
SOUTHEAST ON THE LAKE THROUGH THE NEAR AND INTERMEDIATE TERM. NO
HEADLINES EXPECTED THROUGH THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS/KEC
SHORT TERM...ADAMS
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
136 AM EDT TUE APR 30 2013
.SYNOPSIS...
HIGH PRESSURE AND A DRIER AIRMASS WILL BUILD INTO THE REGION
THROUGH WEDNESDAY. A SLOW MOVING UPPER LEVEL LOW WILL DIVE SOUTH
THROUGH THE CENTRAL U.S. AT THE END OF THE WEEK WITH AN
ACCOMPANYING SURFACE LOW MOVING NORTH ALONG THE MISSISSIPPI. AT
SOME POINT OVER THE WEEKEND...THESE SYSTEMS WILL BECOME STACKED
AND BEGIN TO TRACK EAST THROUGH THE OHIO VALLEY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUD DECK HAS RAPIDLY ERODED OVER THE PAST COUPLE HOURS WHICH IS
RIGHT IN LINE WITH THE 00Z 4/30 NAM AND RECENT RAP RUNS. BOTH THE
NAM AND RAP ALSO HAVE UPSTREAM CLOUDS OVER IN/IL GRADUALLY ERODING
AS THEY APPROACH THE AREA OVERNIGHT. KEPT MAJORITY OF FA UNDER
MOSTLY CLEAR SKIES TONIGHT WITH THE EXCEPTION OF PARTLY CLOUDY IN
THE FAR NORTH. MAIN FORECAST CONCERN WILL BE POSSIBILITY OFF FOG
GIVEN PLENTIFUL LOW LEVEL MOISTURE (DEW POINTS STILL IN THE
50S)...LIGHT TO CALM WINDS...AND A FAVORABLE SETUP FOR RADIATIONAL
COOLING. PATCHY DENSE FOG WILL BE A POSSIBILITY...ESPECIALLY IN
LOW LYING AREAS. PREVIOUS MIN TEMP FORECAST IN THE LOWER 50S STILL
LOOKS TO BE ON TRACK.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
MID AND UPPER LEVEL RIDGING WILL DEVELOP ACROSS THE OHIO VALLEY
TUESDAY INTO WEDNESDAY AHEAD OF THE DIGGING UPPER LOW IN THE PLAINS.
THIS WILL RESULT IN DRY CONDITIONS AND A DECENT WARM UP THROUGH
MIDWEEK. TEMPERATURES ON TUESDAY SHOULD PUSH INTO THE MID TO UPPER
70S WITH HIGHS ON WEDNESDAY IN THE UPPER 70S TO LOWER 80S.
OVERNIGHT LOWS WILL BE SEASONABLY MILD IN THE LOW TO MID 50S. THIS
IS SLIGHTLY ABOVE CLIMO NORMALS IN THE UPPER 40S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ENERGY DIGGING FROM THE NRN ROCKIES WILL CARVE OUT AN UPPER LEVEL
TROF OVER THE NATIONS MID SECTION WITH AN UPPER LOW EVENTUALLY
CLOSING OFF OVER THE CENTRAL PLAINS BY FRIDAY.
STRONG RIDGING AHEAD OF THIS SYSTEM WILL PROVIDE WARM TEMPERATURES
THURSDAY WITH HIGHS 7 TO 10 DEGREES ABOVE NORMAL...RANGING FROM MID
70S NW TO NEAR 80 SE.
NUMERICAL MODEL SOLNS HAVE BEEN SHOWING A HIGHER THAN NORMAL DEGREE
OF SPREAD REGARDING PLACEMENT AND MOVEMENT OF THIS UPPER LOW. ECMWF
HAS HAD BEST RUN TO RUN CONSISTENCY. PREVIOUS ECMWF RUNS AND CMC
RUNS WERE STALLING OUT THE EASTWARD PROGRESSION OF THE UPPER LOW
OVER THE MID MS VLY ON FRIDAY AND THEN LIFTING IT NNW INTO THE NRN
PLAINS SATURDAY. GFS SOLN HAS FLIPPED BACK AND FORTH AND THE LATEST
RUN TAKES THE LOW VERY SLOWLY EASTWARD THRU THE LWR MS VALLEY THIS
WEEKEND AND INTO TN VLY BY EARLY NEXT WEEK...PASSING TO OUR SOUTH.
LATEST NOGAPS POINTS TOWARD THE NW SOLN...WHILE THE GFS ENSEMBLE
MEAN SHOWS EVIDENCE FOR THE LOW STALLING TO OUR WEST. LATEST 12Z
DETERMINISTIC ECMWF SOLN DIGS THE LOW FARTHER SOUTH AND THEN LIFTS
IT NE THIS WEEKEND INTO THE UPPER MS VLY BY SUNDAY EVENING AND THEN
ACRS THE GREAT LAKES EARLY NEXT WEEK.
WITH A WIDE ARRAY OF SOLNS...UNCERTAINTY IS CONSIDERABLY HIGHER THAN
NORMAL FOR THE FCST NEXT WEEK END INTO EARLY NEXT WEEK. HAVE TRENDED
THE FCST SOLN TOWARD THE ECMWF SOLN WITH THE UPR LOW PASSING TO OUR
NORTH. DUE TO LOW CONFIDENCE HAVE LIMITED POPS TO SLIGHT CHC ACRS
THE FAR WEST FRIDAY WITH THE APPROACH OF SFC FRONTAL SYSTEM. WILL
CONTINUE ONLY SLIGHT CHC POPS SATURDAY ACRS THE WEST. HAVE SPREAD
LOW CHANCE POPS ACRS ENTIRE FA FOR SUNDAY/MONDAY TIME FRAME.
TEMP WISE...AFTER ABOVE NORMAL READINGS ON THURSDAY...TEMPS LOOK TO
BE A LTL CLOSER TO NORMAL FRIDAY AND INTO NEXT WEEKEND.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SKIES HAVE CLEARED ACROSS THE AREA EARLY THIS MORNING AND THIS HAS
ALLOWED FOR SOME AREAS OF MAINLY MVFR BR TO DEVELOP. WITH SOME
LINGERING LOW LEVEL MOISTURE...EXPECT MVFR TO OCCASIONALLY IFR BR
TO PERSIST THROUGH DAYBREAK. THE EXCEPTION WILL BE AT KLUK WHERE
RIVER VALLEY FOG WILL KEEP THEM PRIMARILY VLIFR THROUGH DAYBREAK.
MID LEVEL RIDGING WILL OTHERWISE PROVIDE FOR DRY CONDITIONS
THROUGH THE TAF PERIOD WITH JUST A FEW CU DEVELOPING THROUGH LATE
MORNING INTO EARLY AFTERNOON.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...KURZ
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS TULSA OK
851 PM CDT WED MAY 1 2013
.DISCUSSION...
STORMS DEVELOPED WEST AND NORTH OF TULSA DURING PEAK HEATING IN AN
ENVIRONMENT THAT MORE CLOSELY RESEMBLES WHAT YOU WOULD SEE IN THE
SUMMER RATHER THAN THE FIRST OF MAY. THEY WERE PULSE IN
NATURE...AND WHAT IS LEFT OF THEM IS MOVING NORTH OVER OSAGE
COUNTY AT THE MOMENT. THE COLD FRONT HAS UNDERCUT THE STORMS...AND
MAY PROVIDE SOME TEMPORARY LIFT TO KEEP THEM GOING.
HOWEVER...SINCE THE MAIN ENERGY SOURCE HAS SET FOR THE NIGHT...I
THINK THESE STORMS WILL SEE THEIR DEMISE SOON. THE LATEST RUN OF
THE HRRR AND THE 18Z NAM BOTH SUGGEST IT WILL BE FAIRLY QUIET
ALONG THE SURGING FRONT TONIGHT. THE POTENT PV ANOMALY OVER
WESTERN CO IS STILL WELL WEST TONIGHT...AND LIFT FROM THIS SYSTEM
WILL NOT OVERSPREAD THE REGION TILL TOMORROW. THE HRRR SHOWS THE
POST-FRONTAL BAND OF PRECIP MOVING INTO NORTHEAST OK AFTER 12Z.
LACY
&&
.PREV DISCUSSION... /ISSUED 625 PM CDT WED MAY 1 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL FOR THE EARLY PORTION OF THE TAF
PERIOD. A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT
WITH MVFR AND IFR CIGS BEHIND THE FRONT. SCATTERED SHOWERS AND
PERHAPS AN ISOLATED THUNDERSTORM WILL ALSO OCCUR BEHIND THE
FRONT...BUT THE CHANCE OF THUNDER IS TOO LOW TO INCLUDE AT THIS
TIME. GUSTY NW WINDS WILL PERSIST ONCE THE FRONT PASSES. AREAL
COVERAGE OF RAIN WILL INCREASE WITH TIME FROM WEST TO
EAST...HOWEVER,,,THE HIGHEST RAINFALL COVERAGE IS EXPECTED TO
REMAIN ACROSS ERN OK FOR MOST OF THE TAF PERIOD.
PREV DISCUSSION... /ISSUED 358 PM CDT WED MAY 1 2013/
DISCUSSION...
FOLKS...ENJOY THE REST OF TODAY BECAUSE ITS ABOUT TO GO SOUTH
IN A BIG HURRY. UNSEASONABLY STRONG COLD FRONT WHICH HAS BEEN
SHOWN IN LAST SEVERAL MODEL RUNS IS MOVING THROUGH WESTERN OK
THIS AFTERNOON WITH TEMPS FALLING IN LOW-MID 40S WITHIN SHORT TIME
OF FROPA. MOISTURE RETURN AHEAD OF THE FRONT HAS BEEN SUPPRESSED
FAIRLY WELL BY SUMMER LIKE LOW ALONG GULF COAST. THIS LOW HAS
MOVED FAR ENOUGH NORTH TO INFLUENCE WESTERN ARKANSAS WITH ISOLATED
AFTERNOON STORMS OVER HIGHER TERRAIN. NOT MUCH ALONG THE FRONT
YET BUT A FEW STORMS HAVE DEVELOPED OVER SW OK.
CAPPED ATMOSPHERE AND UPPER AIR SUPPORT LAGGING WELL BEHIND THE
FRONT WILL KEEP CHANCE OF SEVERE STORMS ALONG THE FRONT MINIMAL
THROUGH THE EVENING...PLUS ANY STORM THAT CAN GET GOING IN THE
WARM AIR WILL BE UNDERCUT QUICK. THE MAIN MESSAGE WITH THIS SYSTEM
IS THE MUCH COLDER TEMPERATURES...AND THE ALMOST UNTHINKABLE
CHANCE OF WINTER PRECIP BY THURSDAY NIGHT AND EARLY FRIDAY OVER
NORTHERN AREAS. MODELS REMAIN DIVERGENT WITH THE STRENGTH AND
TRACK OF UPPER LEVEL LOW...GFS FARTHER SOUTH AND OVERALL SCARIEST
IN TERMS OF SNOW POTENTIAL...NAM COLDEST BUT FASTER. UK/ECMWF ARE
THE MOST REASONABLE LOOKING AT THIS POINT AND HAVE BEEN FOLLOWED...
WITH A NOD TO THE LOCAL WRF FOR TEMP TRENDS ALONG AND WEST OF THE
FRONT TONIGHT.
PRECIP SHOULD BEGIN TO INCREASE LATER THURSDAY AND THU NIGHT AS
THE UPPER SYSTEM MOVES CLOSER...AND THIS AFFORDS US OUR SHOT AT
SNOW. GIVEN THE TIME OF YEAR...IT WILL TAKE A BURST OF HEAVY
SNOWFALL OVER A LONG ENOUGH PERIOD TO ACCUMULATE SNOW AS SFC TEMPS
LIKELY TO REMAIN JUST ABOVE FREEZING. STILL...IT WILL ONLY TAKE A
SMALL AMOUNT TO CAUSE SERIOUS ISSUES IN TERMS OF ACCUMULATING ON
TREES WITH LEAVES. CONFIDENCE NOT HIGH ENOUGH FOR ADVISORY AS A
DEGREE OR TWO WILL MAKE ALL THE DIFFERENCE...BUT A STRONGLY WORDED
SPS WILL BE ISSUED DUE MAINLY TO THE UNPRECEDENTED NATURE OF THIS
EVENT.
OVERALL TREND WILL BE FOR PRECIP TO DIMINISH DURING THE DAY FRIDAY
WITH RECORD LOW MAXES LIKELY AS TEMPS STRUGGLE TO REACH 50 DEGREES
IN AREAS WHERE PRECIP LINGERS LONG ENOUGH. COULD SEE A BIT OF WRAP
AROUND PRECIP MIX WITH SNOW OVER NW ARKANSAS FRIDAY NIGHT.
FREEZING TEMPS POSSIBLE THU NIGHT IN NE OK AND NW AR FRI NIGHT...
FREEZE WATCH ISSUED FOR NE OK THU NIGHT AND ONE MAY END UP BEING
NEEDED FOR NW ARKANSAS FRI NIGHT.
BEYOND THAT A RETURN TO MORE NORMAL SPRING WEATHER SHOULD OCCUR
WITH TEMPS CLOSER TO NORMAL BY EARLY NEXT WEEK. ANOTHER SYSTEM
COULD BRING SHOWERS AND THUNDERSTORMS TUE/WED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 42 43 34 49 / 60 70 90 40
FSM 62 64 38 50 / 20 70 90 40
MLC 47 48 35 51 / 30 60 90 20
BVO 40 41 33 49 / 70 80 90 50
FYV 53 53 35 46 / 20 70 100 50
BYV 54 55 37 44 / 20 70 100 60
MKO 47 48 35 50 / 40 60 100 40
MIO 44 45 34 47 / 60 80 100 60
F10 44 44 34 51 / 40 70 90 30
HHW 54 56 37 54 / 20 50 60 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FREEZE WATCH FROM 1 AM FRIDAY TO 10 AM FRIDAY FOR OKZ054-OKZ055-
OKZ056-OKZ057-OKZ059-OKZ060-OKZ061-OKZ064-OKZ065-OKZ066.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
514 PM EDT TUE APR 30 2013
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE OUTER BANKS OF NORTH
CAROLINA WILL MAINTAIN A SOUTHEASTERLY FLOW OF MOIST AIR INTO
CENTRAL PENNSYLVANIA TONIGHT...KEEPING CLOUDS AROUND WITH A
MENTION OF DRIZZLE FOR THE SOUTHERN MOUNTAINS. A HIGH AMPLITUDE
BLOCKING RIDGE WILL SET UP ACROSS THE REGION FOR THE SECOND HALF
OF THE WEEK...BRINGING DRY AND MILD WEATHER WHICH IS EXPECTED TO
LAST INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MAIN BELT OF ANOMALOUS EASTERLIES SHIFTS GRADUALLY SOUTH TO
THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS OVERNIGHT FROM THE EAST. STUBBORN STRATOCU
SHOULD LINGER THE LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY
DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR -
THOUGH THEY HAVE BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER
THE PAST 24 HRS/.
LOW TEMPS WILL BE IN THE 40S...WITH COOLEST READINGS IN THE
NORTHEAST AND EAST WHERE CLOUDS WILL THIN FIRST AND DEWPOINTS
WILL LOWER FIRST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE BEGINS TO QUICKLY AMPLIFY
FROM THE TENNESSEE VALLEY TO EASTERN CANADA ON WED. AFTER A CLOUDY
START IN THE SW...SKIES SHOULD BECOME PARTLY CLOUDY EVERYWHERE BY
LATE MORNING WITH SUNSHINE CONTINUING TO INCREASE IN THE
AFTERNOON AS SUBSIDENCE DEEPENS UNDER THE BUILDING HIGH.
HIGH TEMPS WEDNESDAY WILL WARM BY 8-10F COMPARED TO
TUESDAY...WHICH WILL BE NEAR NORMAL ACROSS THE SUSQ VALLEY...AND
5-8F DEGREES ABOVE NORMAL OVER THE NRN AND WESTERN MTNS. LOWS WED
NIGHT WILL BE CHILLY WITH STRENGTHENING HIGH PRESSURE BRINGING
LIGHT WINDS AND DRIER AIR. READINGS WILL BOTTOM OUT IN THE
40S...WITH SOME UPPER 30S POSS IN NORTHEASTERN MTNS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE 30/12Z GLOBAL NUMERICAL GUIDANCE CONTINUES TO ADVERTISE A HIGHLY
AMPLIFIED MERIDIONAL FLOW PATTERN AT 500MB THROUGH THE MEDIUM RANGE
PERIOD...WITH AN ANOMALOUS RIDGE/TROUGH/RIDGE CONFIGURATION EXPECTED
FROM JUST OFFSHORE THE PAC NW TO THE CENTRAL US AND INTERIOR NORTHEAST
STATES.
A MID-ATLANTIC FORECAST PERSPECTIVE SHOWS A SHARP 580DM RIDGE
CENTERED BETWEEN THE AFOREMENTIONED CENTRAL CONUS H5 TROUGH/CLOSED
LOW AND COMPACT H5 ENERGY PROGGED TO DROP SWD FROM THE MARITIMES
ALONG/JUST OFFSHORE THE NEW ENGLAND COAST ON DAY 3-4 /THUR-FRI/.
THIS FEATURE WILL RETREAT INTO THE NRN ATLC BY THE WEEKEND...WITH
THE FOCUS SHIFTING TO THE EVOLUTION OF THE CLOSED LOW OVER THE
CENTRAL STATES.
THE ECMWF LIES ON THE WWD SIDE OF THE DETERMINISTIC ENVELOPE SHOWING
A MORE COASTAL TRACK WITH THE ENERGY DROPPING OFFSHORE THE NE COAST
EARLY IN THE PERIOD. HOWEVER THE OVERALL MODEL SPREAD IS PRETTY LOW
WITH THIS FEATURE...WHICH SHOULD SEND A BACKDOOR COLD FRONT INTO THE
REGION ON FRIDAY AND ACCENTUATE A WEST-EAST TEMPERATURE GRADIENT.
THE DOMINANT SYNOPTIC FEATURE DRIVING THE SENSIBLE WEATHER IN
CENTRAL PA THROUGH THE BALANCE OF THE PERIOD WILL BE THE HIGH
AMPLITUDE UPPER-LEVEL RIDGE...WHICH SHOULD EFFECTIVELY BLOCK PCPN
ASSOCD WITH THE CENTRAL US CLOSED LOW FROM REACHING THE
NORTHEAST/MID-ATLC STATES AT LEAST THROUGH THE UPCOMING WEEKEND.
THE OPERATIONAL MODELS AND THEIR ENSEMBLE MEANS HAVE MANY VARIED
SOLUTIONS CONCERNING THE EVENTUAL EWD PROGRESSION OF THE CENTRAL US
CLOSED LOW. IN GENERAL...THERE APPEARS TO BE A SLIGHTLY SLOWER AND
SOUTHWARD TREND IN THE MOST RECENT NON-NCEP MODEL DATA. THE SLOWER
TREND MAKES SENSE GIVEN THAT THE MODELS USUALLY TRY TO BREAK DOWN
THESE PATTERNS TOO QUICKLY. THE LATE-SPRING/EARLY MAY TIMEFRAME IS
ALSO A CLIMATALOGICALLY FAVORED PERIOD FOR BLOCKY PATTERNS/CUT-OFF
LOWS. WITH REGARD TO THE EWD MVMT OF THE CLOSED LOW AND CORRESPONDING
CHCS FOR PCPN...WILL UTILIZE AN EVEN BLEND OF AVAILABLE GUIDANCE. THIS
IDEA SEEMS TO FIT THE WPC PREFERENCE OF AN INTERMEDIATE 12Z CANADIAN
OR EC/GEFS MEAN SOLUTION.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
LARGE ANTICYCLONE TO OUR NORTH AND EAST KEEPS US IN THE EASTERLY
FLOW. THE FLOW SHOWS SOME SIGNS OF WEAKENING AND THE SATELLITE
IMAGERY SHOWS THE SHRINKING LOW CLOUD REGION STUCK OVER CENTRAL
PENNSYLVANIA. 4KM MODELS AND RADAR IMPLY SOME LINGERING DZ/-RA IN
SW MOUNTAINS AND MOST LOCATIONS WILL BE IN THE MVFR/VFR RANGE.
SOME BREAKS IN CLOUDS NEAR KLNS-KMDT NOW COMING IN FROM THE EAST
AND KBFD IS ABOUT 50 MILES TOO FAR EAST OF THE VFR REGION.
THINGS SHOULD IMPROVE WEDNESDAY AS THE FLOW WEAKENS AS STATED IN
PREVIOUS DISCUSSION...THE MAIN BELT OF ANOMALOUS EASTERLY WINDS SHIFTS
GRADUALLY SOUTH TO THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE
VALLEY TO EASTERN CANADA. IN ADDITION...DRIER AIR IS ALREADY
BEGINNING TO ADVECT IN FROM THE EAST...WHICH WILL AID IN RAISING
CIGS AND GRADUALLY DIMINISHING CLOUDS FROM THE EAST THIS AFTERNOON
INTO THE OVERNIGHT. STUBBORN LOWER STRATOCU SHOULD LINGER THE
LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY DRIZZLE WILL REMAIN
POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR - THOUGH THEY HAVE
BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER THE PAST 24 HRS/.
LINGERING LOW CIGS WILL GIVE WAY TO VFR CONDITIONS AREAWIDE ON WED
AS HIGH PRESSURE RIDGE STRENGTHENS OVER THE REGION. THIS WILL
BEGIN AN EXTENDED PERIOD OF EXCELLENT FLYING CONDITIONS.
.OUTLOOK...
WED...LOW CIGS POSS EARLY OVR THE W MTNS...OTHERWISE VFR.
THU-SUN...VFR. NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...GRUMM/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
321 PM EDT TUE APR 30 2013
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE OUTER BANKS OF NORTH
CAROLINA WILL MAINTAIN A SOUTHEASTERLY FLOW OF MOIST AIR INTO
CENTRAL PENNSYLVANIA TONIGHT...KEEPING CLOUDS AROUND WITH A
MENTION OF DRIZZLE FOR THE SOUTHERN MOUNTAINS. A HIGH AMPLITUDE
BLOCKING RIDGE WILL SET UP ACROSS THE REGION FOR THE SECOND HALF
OF THE WEEK...BRINGING DRY AND MILD WEATHER WHICH IS EXPECTED TO
LAST INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MAIN BELT OF ANOMALOUS EASTERLIES SHIFTS GRADUALLY SOUTH TO
THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS OVERNIGHT FROM THE EAST. STUBBORN STRATOCU
SHOULD LINGER THE LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY
DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR -
THOUGH THEY HAVE BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER
THE PAST 24 HRS/.
LOW TEMPS WILL BE IN THE 40S...WITH COOLEST READINGS IN THE
NORTHEAST AND EAST WHERE CLOUDS WILL THIN FIRST AND DEWPOINTS
WILL LOWER FIRST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE BEGINS TO QUICKLY AMPLIFY
FROM THE TENNESSEE VALLEY TO EASTERN CANADA ON WED. AFTER A CLOUDY
START IN THE SW...SKIES SHOULD BECOME PARTLY CLOUDY EVERYWHERE BY
LATE MORNING WITH SUNSHINE CONTINUING TO INCREASE IN THE
AFTERNOON AS SUBSIDENCE DEEPENS UNDER THE BUILDING HIGH.
HIGH TEMPS WEDNESDAY WILL WARM BY 8-10F COMPARED TO
TUESDAY...WHICH WILL BE NEAR NORMAL ACROSS THE SUSQ VALLEY...AND
5-8F DEGREES ABOVE NORMAL OVER THE NRN AND WESTERN MTNS. LOWS WED
NIGHT WILL BE CHILLY WITH STRENGTHENING HIGH PRESSURE BRINGING
LIGHT WINDS AND DRIER AIR. READINGS WILL BOTTOM OUT IN THE
40S...WITH SOME UPPER 30S POSS IN NORTHEASTERN MTNS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE 30/12Z GLOBAL NUMERICAL GUIDANCE CONTINUES TO ADVERTISE A HIGHLY
AMPLIFIED MERIDIONAL FLOW PATTERN AT 500MB THROUGH THE MEDIUM RANGE
PERIOD...WITH AN ANOMALOUS RIDGE/TROUGH/RIDGE CONFIGURATION EXPECTED
FROM JUST OFFSHORE THE PAC NW TO THE CENTRAL US AND INTERIOR NORTHEAST
STATES.
A MID-ATLANTIC FORECAST PERSPECTIVE SHOWS A SHARP 580DM RIDGE
CENTERED BETWEEN THE AFOREMENTIONED CENTRAL CONUS H5 TROUGH/CLOSED
LOW AND COMPACT H5 ENERGY PROGGED TO DROP SWD FROM THE MARITIMES
ALONG/JUST OFFSHORE THE NEW ENGLAND COAST ON DAY 3-4 /THUR-FRI/.
THIS FEATURE WILL RETREAT INTO THE NRN ATLC BY THE WEEKEND...WITH
THE FOCUS SHIFTING TO THE EVOLUTION OF THE CLOSED LOW OVER THE
CENTRAL STATES.
THE ECMWF LIES ON THE WWD SIDE OF THE DETERMINISTIC ENVELOPE SHOWING
A MORE COASTAL TRACK WITH THE ENERGY DROPPING OFFSHORE THE NE COAST
EARLY IN THE PERIOD. HOWEVER THE OVERALL MODEL SPREAD IS PRETTY LOW
WITH THIS FEATURE...WHICH SHOULD SEND A BACKDOOR COLD FRONT INTO THE
REGION ON FRIDAY AND ACCENTUATE A WEST-EAST TEMPERATURE GRADIENT.
THE DOMINANT SYNOPTIC FEATURE DRIVING THE SENSIBLE WEATHER IN
CENTRAL PA THROUGH THE BALANCE OF THE PERIOD WILL BE THE HIGH
AMPLITUDE UPPER-LEVEL RIDGE...WHICH SHOULD EFFECTIVELY BLOCK PCPN
ASSOCD WITH THE CENTRAL US CLOSED LOW FROM REACHING THE
NORTHEAST/MID-ATLC STATES AT LEAST THROUGH THE UPCOMING WEEKEND.
THE OPERATIONAL MODELS AND THEIR ENSEMBLE MEANS HAVE MANY VARIED
SOLUTIONS CONCERNING THE EVENTUAL EWD PROGRESSION OF THE CENTRAL US
CLOSED LOW. IN GENERAL...THERE APPEARS TO BE A SLIGHTLY SLOWER AND
SOUTHWARD TREND IN THE MOST RECENT NON-NCEP MODEL DATA. THE SLOWER
TREND MAKES SENSE GIVEN THAT THE MODELS USUALLY TRY TO BREAK DOWN
THESE PATTERNS TOO QUICKLY. THE LATE-SPRING/EARLY MAY TIMEFRAME IS
ALSO A CLIMATALOGICALLY FAVORED PERIOD FOR BLOCKY PATTERNS/CUT-OFF
LOWS. WITH REGARD TO THE EWD MVMT OF THE CLOSED LOW AND CORRESPONDING
CHCS FOR PCPN...WILL UTILIZE AN EVEN BLEND OF AVAILABLE GUIDANCE. THIS
IDEA SEEMS TO FIT THE WPC PREFERENCE OF AN INTERMEDIATE 12Z CANADIAN
OR EC/GEFS MEAN SOLUTION.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE MAIN BELT OF ANOMALOUS EASTERLY WINDS SHIFTS GRADUALLY SOUTH
TO THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS FROM THE EAST THIS AFTERNOON INTO THE OVERNIGHT.
STUBBORN LOWER STRATOCU SHOULD LINGER THE LONGEST /THROUGH 12Z/
IN THE SW WHERE SPOTTY DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER
THE 4KM NAM AND HRRR - THOUGH THEY HAVE BEEN OVERDOING POTENTIAL
FOR LIGHT PRECIP OVER THE PAST 24 HRS/.
LINGERING LOW CIGS WILL GIVE WAY TO VFR CONDITIONS AREAWIDE ON WED
AS HIGH PRESSURE RIDGE STRENGTHENS OVER THE REGION. THIS WILL
BEGIN AN EXTENDED PERIOD OF EXCELLENT FLYING CONDITIONS.
.OUTLOOK...
WED...LOW CIGS POSS EARLY OVR THE W MTNS...OTHERWISE VFR.
THU-SUN...VFR. NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
302 PM EDT TUE APR 30 2013
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE NEAR THE OUTER BANKS OF NORTH CAROLINA
WILL MAINTAIN A SOUTHEASTERLY FLOW OF MOIST AIR INTO CENTRAL
PENNSYLVANIA TONIGHT...KEEPING CLOUDS AROUND WITH A MENTION OF
DRIZZLE FOR THE SOUTHERN MOUNTAINS. A HIGH AMPLITUDE BLOCKING
RIDGE WILL SET UP ACROSS THE REGION FOR THE SECOND HALF OF THE
WEEK...BRINGING DRY AND MILD WEATHER WHICH IS EXPECTED TO LAST
INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MAIN BELT OF ANOMALOUS EASTERLIES SHIFTS GRADUALLY SOUTH TO
THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS OVERNIGHT FROM THE EAST. STUBBORN STRATOCU
SHOULD LINGER THE LONGEST /THROUGH 12Z/ IN THE SW WHERE SPOTTY
DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER THE 4KM NAM AND HRRR -
THOUGH THEY HAVE BEEN OVERDOING POTENTIAL FOR LIGHT PRECIP OVER
THE PAST 24 HRS/.
LOW TEMPS WILL BE IN THE 40S...WITH COOLEST READINGS IN THE
NORTHEAST AND EAST WHERE CLOUDS WILL THIN FIRST AND DEWPOINTS
WILL LOWER FIRST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOMALOUS /+2-3 SIGMA/ 500 MB RIDGE BEGINS TO QUICKLY AMPLIFY
FROM THE TENNESSEE VALLEY TO EASTERN CANADA ON WED. AFTER A CLOUDY
START IN THE SW...SKIES SHOULD BECOME PARTLY CLOUDY EVERYWHERE BY
LATE MORNING WITH SUNSHINE CONTINUING TO INCREASE IN THE
AFTERNOON AS SUBSIDENCE DEEPENS UNDER THE BUILDING HIGH.
HIGH TEMPS WEDNESDAY WILL WARM BY 8-10F COMPARED TO
TUESDAY...WHICH WILL BE NEAR NORMAL ACROSS THE SUSQ VALLEY...AND
5-8F DEGREES ABOVE NORMAL OVER THE NRN AND WESTERN MTNS. LOWS WED
NIGHT WILL BE CHILLY WITH STRENGTHENING HIGH PRESSURE BRINGING
LIGHT WINDS AND DRIER AIR. READINGS WILL BOTTOM OUT IN THE
40S...WITH SOME UPPER 30S POSS IN NORTHEASTERN MTNS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE SHOWS A HIGHLY
AMPLIFIED 500MB PATTERN THROUGH THE REMAINDER OF THE PERIOD...WITH
AN OMEGA BLOCK DEVELOPING FROM THE CENTRAL/EASTERN CONUS INTO THE
WRN ATLANTIC. FORTUNATELY...THE UPPER RIDGE PORTION OF THE BLOCK
SHOULD SET-UP OVER THE INTERIOR NORTHEAST AND PROVIDE SEVERAL DAYS
OF FAIR AND DRY WEATHER WITH ABOVE NORMAL DAYTIME TEMPS.
THE MODELS ARE USUALLY TOO QUICK TO BREAK DOWN BLOCKING
PATTERNS...WHICH ALSO TEND TO BE MORE FREQUENT IN LATE SPRING.
THEREFORE PREFER AN ECMWF-BASED SOLUTION WITH NO SIGNIFICANT KICKER
SYSTEM NEARBY. ALSO WEIGHTED TEMPERATURES TOWARD A BLEND OF THE
OPERATIONAL AND ENSEMBLE ECMWF MOS PRODUCTS. THE SLIGHT
MARITIME/SELY COMPONENT TO THE WIND FIELD SHOULD KEEP HIGHS NEAR
SEASONAL/EARLY MAY NORMALS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE MAIN BELT OF ANOMALOUS EASTERLY WINDS SHIFTS GRADUALLY SOUTH
TO THE CAROLINAS TONIGHT INTO WEDNESDAY...WHILE AN ANOMALOUS /+2-3
SIGMA/ 500 MB RIDGE AMPLIFIES FROM THE TENNESSEE VALLEY TO EASTERN
CANADA. IN ADDITION...DRIER AIR IS ALREADY BEGINNING TO ADVECT IN
FROM THE EAST...WHICH WILL AID IN RAISING CIGS AND GRADUALLY
DIMINISHING CLOUDS FROM THE EAST THIS AFTERNOON INTO THE OVERNIGHT.
STUBBORN LOWER STRATOCU SHOULD LINGER THE LONGEST /THROUGH 12Z/
IN THE SW WHERE SPOTTY DRIZZLE WILL REMAIN POSS OVERNIGHT /AS PER
THE 4KM NAM AND HRRR - THOUGH THEY HAVE BEEN OVERDOING POTENTIAL
FOR LIGHT PRECIP OVER THE PAST 24 HRS/.
LINGERING LOW CIGS WILL GIVE WAY TO VFR CONDITIONS AREAWIDE ON WED
AS HIGH PRESSURE RIDGE STRENGTHENS OVER THE REGION. THIS WILL
BEGIN AN EXTENDED PERIOD OF EXCELLENT FLYING CONDITIONS.
.OUTLOOK...
WED...LOW CIGS POSS EARLY OVR THE W MTNS...OTHERWISE VFR.
THU-SUN...VFR. NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RXR
NEAR TERM...RXR
SHORT TERM...RXR
LONG TERM...LAMBERT/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1024 PM CDT WED MAY 1 2013
.UPDATE...
STRONGER SURFACE PRESSURE GRADIENT GRADUALLY DEVELOPING AND WE ARE
SEEING MORE SITES REACHING WELL INTO WIND ADVISORY LEVELS VIA THE
WEST TEXAS MESONET. STRONGER WINDS ALSO DEVELOPING OVER CASTRO
COUNTY JUST SHY OF HIGH WIND WARNING LEVELS. WE OPTED TO EXPAND
THE HIGH WIND WARNING INTO CASTRO COUNTY AND THE WIND ADVISORY
ACROSS THE ROLLING PLAINS. THE LATEST WRF/NAM AND HRRR RUNS ARE
CONSISTENT BREAKING LIGHT PRECIPITATION OUT ACROSS MAINLY NORTHERN
ROLLING PLAINS BEFORE MIDNIGHT...THEN EXPANDING BACK OVER MUCH OF
OUR AREA EARLY THURSDAY UNTIL ABOUT MID THURSDAY MORNING WITH
COMBINATION OF ISENTROPIC UPGLIDE...SLOPED FRONTOGENETIC FORCING...
AND DEEPER SYNOPTIC FORCING WITH UPPER TROUGH SWINGING OVERHEAD.
MOISTURE REMAINS LIMITED MOSTLY AROUND 650-700 MB OR LOWER SO
PRECIPITATION TOTALS EXPECTED TO BE LIGHT...TRACE TO 10 HUNDREDTHS
OF AN INCH FOR THE MOST PART. WE INCREASED PRECIPITATION CHANCES
OVER MOST OF THE AREA LATER TONIGHT AND EARLY THURSDAY. PHASE
CONTINUES TO FAVOR A SLEET/LIQUID MIX BECOMING A SLEET/FROZEN/LIQUID
MIX ON THE CAP-ROCK EARLY THURSDAY. MOST AREAS OVER THE ROLLING
PLAINS SHOULD REMAIN LIQUID...WITH EXCEPTION OF NORTHERN ROLLING
PLAINS WHICH ALSO MAY SEE SLEET MIXING IN EARLY THURSDAY. WITH THE
LIGHT AMOUNTS WE HAVE OPTED FOR NO WINTER WEATHER HIGH-LITES...
ALTHOUGH A BAND OR TWO OF MODERATE INTENSITY PRECIPITATION WITH
TEMPERATURES HOVERING NEAR FREEZING EARLY THURSDAY HAS SOME
POTENTIAL FOR LIGHT ACCUMULATIONS OVER THE NORTH-CENTRAL TO
NORTHEAST PART OF OUR AREA. UPDATE HAS BEEN ISSUED. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 626 PM CDT WED MAY 1 2013/
AVIATION...
BREEZY NORTH WINDS HAS AND WILL CONTINUE TO PERSIST THROUGHOUT THE
TAF PERIOD. FEW IFR CLOUD DECKS WERE NOTED AT KLBB AND AS WE HEAD
INTO THE EVENING...INCREASING CLOUDINESS WILL ENSUE. WIND SPEEDS
EQUATING WIND ADVISORY SPEEDS /31 MPH/ ARE ANTICIPATED TONIGHT
MORE SO AT KLBB. MOISTENING LOW LEVELS OVERNIGHT WILL ENCOURAGE
MVFR CLOUD DECKS AND THE POTENTIAL FOR -RA /OR POSSIBLY A WINTRY
MIX/. SKIES WILL SLOWLY CLEAR FROM WEST TO EAST MID-MORNING
TOMORROW AND WILL SHOW IN THE TAF...CLOUDS BREAKING UP INITIALLY
AT KLBB THEN EVENTUALLY KCDS.
PREV DISCUSSION... /ISSUED 332 PM CDT WED MAY 1 2013/
SHORT TERM...
A VERY DYNAMIC LATE SPRING STORM TO BRING STRONG NORTH WINDS AND
CHANCE FOR GENERALLY LIGHT RAIN AND EVEN POSSIBILITY OF LIGHT WINTRY
PRECIPITATION TO THE AREA. THE PARENT UPPER LOW/TROUGH CONTINUES TO
STRENGTHEN OVER THE INTER-MOUNTAIN WEST WHILE AT THE SFC THE STRONG
COLD FRONT HAS ALREADY CLEARED THE FCST AREA. MAIN THREAT LOOKING TO
BE WINDS AS VERY STRONG PRESSURE RISES ARE EXPECTED TO MOVE SWD DOWN
THE SRN HIGH PLAINS WITH A BARRIER JET LIKELY DEVELOPING JUST ON THE
LEE OF THE MOUNTAINS OF CNTL NM. COMBINATION WILL MEAN AT LEAST WIND
ADVISORY LEVEL WINDS FOR ALL OF THE AREA ON THE CAPROCK WITH GOOD
POTENTIAL FOR WARNING CRITERIA TO BE MET ACROSS THE NW /SPECIFICALLY
PARMER AND BAILEY COUNTIES/.
AS FOR PRECIP...HAVE BEEN CONCERNED WITH RECENT MODEL BIASES TOWARD
BEING TOO WET IN THE POST-FRONTAL AIR MASS AS THEY HAVE BEEN WITH
THE LAST SEVERAL OF THESE EVENTS. IN ESSENCE...IT APPEARS THAT THE
NAM IN PARTICULAR CONVERTS TOO MUCH OF THE LIFT FROM FRONTOGENETICAL
AND ISENTROPIC MECHANISMS TO PRECIPITATION POSSIBLY FROM TOO
AGGRESSIVELY MOISTENING THE DEEPENING COLD LAYER. INSTEAD RESULT HAS
TOO OFTEN BEEN ONLY LOW CLOUDS HIGHER THAN PROGGED AS STRONG COLD
AND DRY ADVECTION WORKS IN IN THE NEAR-SFC LAYER. IT APPEARS THAT
THIS EVENT MAY WORK SIMILARLY. EXCEPTION TODAY MAY BE THE STRENGTH
OF SRN EXTENT OF THE UPPER TROUGH TO THE WEST. Q-VECTOR PROGS
SUGGEST THE TAIL END OF THE LARGE SCALE ASCENT MAY BE FAR ENOUGH
SOUTH TO BRING AN ADDITIONAL PRECIPITATION GENERATION MECHANISM INTO
PLAY LATE TONIGHT THEN BLEEDING OVER PAST 12Z THURSDAY. IT DOES NOT
LOOK LIKE THE FORMER MECHANISMS WILL TEMPORALLY OVERLAP THE LATTER
ONE...BUT IT DOES OFFER AN ADDITIONAL MEANS BY WHICH SOME LIGHT
PRECIP MAY BE GENERATED. OVERALL...GIVEN SKEPTICISM IN RELATION TO
NAM BIASES IN PARTICULAR...WILL FAVOR THE LOWER POPS OF MAVMOS. THAT
MEANS A SMALL REDUCTION IN FCST POPS FOR TONIGHT INTO THURSDAY
MORNING. PROBLEMS PERSIST REGARDING PRECIP PHASE AS WELL. MODEL
SOUNDINGS SHOW POTENTIAL PRECIP GENERATION ZONE ALOFT BEING IN AN
AREA OF RELATIVE WARMTH WITH POTENTIAL FOR SUPERCOOLED DROPS TO FALL
THROUGH THE COLD AIR MASS AT AND JUST ABOVE THE SFC. THIS WOULD TEND
TO FAVOR DRIZZLE IF DRY SUB-CLOUD AIR DOES NOT WIN OUT. SITUATION
COULD CHANGE WITH LARGER SCALE ASCENT FROM THE UPPER TROUGH AND
POTENTIAL FOR IT TO COOL TEMPS ALOFT. THAT COULD LEAD TO SOME SNOW
MAKING INTO WHAT MAY OR MAY NOT BE A MID LEVEL WARM ZONE AT THAT
TIME. SFC TEMPS WOULD FAVOR SNOW OR SLEET IN THIS REGIME MOST LIKELY
ONLY ACROSS THE NWRN AND NCNTL ZONES LATE TONIGHT AND EARLY
THURSDAY. THUS...HAVE PULLED BACK THE WINTRY PRECIP MENTION A BIT
FROM PREVIOUS FCSTS.
FINAL ISSUE FOR TONIGHT IS POTENTIAL FOR A LIGHT FREEZE. THAT SEEMS
MOST LIKELY IN THOSE NWRN AND NCNTL ZONES JUST MENTIONED...AND
WILL ISSUE A FREEZE WARNING FOR THOSE AREAS...ALTHOUGH BETTER
CHANCE FOR A FREEZE OR EVEN HARD FREEZE COMES 24 HOURS LATER.
TEMPS TO BE SLOW TO RISE THURSDAY UNTIL SOME CLEARING CAN BEGIN
TO WORK IN FROM THE WEST DURING THE AFTN. FCST TEMPS WILL BE JUST
BELOW MOS NUMBERS FOR MUCH OF THE AREA.
LONG TERM...
ONE MORE LATE SEASON FREEZE LOOKS TO OCCUR FOR THE SOUTH
PLAINS...ROLLING PLAINS...AND EXTREME SOUTHERN TEXAS PANHANDLE
THURSDAY NIGHT INTO FRIDAY MORNING. AN UNSEASONABLY COLD AIRMASS
WILL BE LOCKED IN ACROSS THE AREA AS SURFACE RIDGING...LIGHT
WINDS...AND CLEAR SKIES PROMOTE STRONG RADIATIONAL COOLING.
FORECASTING BOTH LUBBOCK AND CHILDRESS TO SET DAILY RECORD LOW
TEMPERATURES OF 29 AND 31 RESPECTIVELY (RECORDS ARE 30 AND 34). WILL
KEEP PREVIOUSLY ISSUED FREEZE WATCH IN EFFECT FOR THE ENTIRE
FORECAST AREA.
TEMPERATURES WILL BEGIN WARMING FRIDAY AS WARM AIR PUMPS INTO THE
REGION ALOFT ALONG WITH DOWNSLOPING WINDS. READINGS WILL REBOUND
BACK INTO THE 60S FRIDAY...FOLLOWED BY 60S AND 70S FOR THE
WEEKEND...STILL BELOW NORMAL VALUES OF AROUND 80 FOR THIS TIME OF
YEAR. OVERNIGHT LOWS WILL REMAIN ABOVE FREEZING BEGINNING FRIDAY
NIGHT THROUGH THE REMAINDER OF THE EXTENDED...WITH THE ONE EXCEPTION
PERHAPS BEING FRIDAY NIGHT ACROSS THE EXTREME SOUTHWEST PANHANDLE
AND ADJACENT PORTIONS OF THE SOUTH PLAINS. UPPER LEVEL RIDGING WILL
BUILD IN THROUGHOUT THE WEEKEND RAISING HEIGHTS AND AIDING IN THIS
WARMING TREND...BUT A DISTURBANCE LOOKS TO ATTEMPT TO BREAK DOWN
THIS FEATURE BY LATE WEEKEND OR EARLY NEXT WEEK. MOISTURE WILL TRY
TO MAKE A RETURN...BUT NOWHERE NEAR ENOUGH TO WARRANT POPS AT THIS
TIME.
WILL HAVE TO CONTINUE MONITORING THE EVOLUTION OF AN UPPER LOW
ENTERING THE WESTERN COAST OF THE COUNTRY HEADING INTO THE TUESDAY
TIME-FRAME AND BEYOND. THE CURRENT RUN OF THE ECMWF HAS A PROGRESSIVE
SYSTEM MOVING TOWARD THE PLAINS AND DRAWING UP SOME MOISTURE FROM
THE SOUTH...WHILE THE LATEST GFS ESTABLISHES AN OMEGA BLOCKING
PATTERN NEAR THE HEART OF THE COUNTRY...THUS KEEPING THIS SYSTEM
CONFINED WEST OF THE ROCKIES. MUCH REFINEMENT TO COME IN SUBSEQUENT
FORECASTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 30 45 24 62 32 / 20 20 0 0 0
TULIA 31 44 26 61 34 / 50 40 0 0 0
PLAINVIEW 33 45 26 62 35 / 50 40 0 0 0
LEVELLAND 34 47 26 66 36 / 40 30 0 0 0
LUBBOCK 35 46 29 66 36 / 50 40 0 0 0
DENVER CITY 35 50 29 65 38 / 30 30 0 0 0
BROWNFIELD 35 48 29 66 38 / 40 30 0 0 0
CHILDRESS 37 47 31 62 38 / 60 60 0 0 0
SPUR 37 47 30 65 37 / 60 60 0 0 0
ASPERMONT 40 46 31 65 39 / 60 60 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
THE FOLLOWING ZONES: TXZ021>044.
WIND ADVISORY UNTIL 6 AM CDT THURSDAY FOR THE FOLLOWING ZONES:
TXZ023>026-028>044.
FREEZE WARNING FROM 4 AM TO 9 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: TXZ021>023-027-028.
HIGH WIND WARNING UNTIL 6 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: TXZ021-022-027.
&&
$$
05/99/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1127 AM CDT TUE APR 30 2013
.UPDATE...
ONLY MINOR TWEAKS LIKELY TO THE ONGOING FCST. FOCUS CONTINUES ON
SMALL CHANCE OF ISOLATED HIGH-BASED TSRA THIS AFTERNOON AND EARLY
EVENING ALONG AND JUST EAST OF THE I-27 CORRIDOR. THE WRF-NAM
CONTINUES TO BE THE ONLY MODEL THAT GENERATES ANY MEANINGFUL QPF
WHILE THE RAP BARELY HINTS AT THE POSSIBILITY OF MEASURABLE
PRECIP...AND THE TTU-WRF REMAINS DRY. MODEST NEAR-SFC MOISTURE
VERY SHALLOW PER 12Z KAMA SOUNDING SUGGESTS ANY INSTABILITY LIKELY
RELEASED CLOSER TO 550 MB. PROBABILITY LOOKS SMALL BUT MENTION OF
TSRA REMAINS VALID. ANY SEVERE THREAT LIKELY LIMITED TO WIND.
&&
.AVIATION...
PROBABILITY OF TSRA AT KLBB TOO LOW TO INSERT MENTION IN THE TAF.
SOME INDICATION THAT LOW CLOUDS COULD MOVE INTO THE ROLLING PLAINS FROM
THE SOUTHEAST LATE TONIGHT...AND MAY NEED TO INSERT A MENTION OF
MVFR CIGS AT KCDS. FINALLY...ANOTHER STRONG COLD FRONT TO MOVE
THROUGH THE AREA PROBABLY BETWEEN 12Z AND 18Z WEDNESDAY WITH WINDS
POSSIBLY AROUND 25 KTS SUSTAINED.
&&
.PREV DISCUSSION... /ISSUED 645 AM CDT TUE APR 30 2013/
AVIATION...
THE NOCTURNAL LLJ IS WEAKENING PER TTU SODAR DATA AND SHEAR
SHOULD BE BELOW LLWS CRITERIA BY 12Z OR SHORTLY AFTER.
OTHERWISE...EXPECT SRLY WINDS AT BOTH TERMINALS TODAY WITH PREVAILING
VFR CONDITIONS. THERE IS A SLIM CHANCE OF TSRA AND/OR OUTFLOW WINDS IN
THE VICINITY OF EITHER TERMINAL THIS AFTERNOON AND EVENING...BUT
PROBABILITY WAS DEEMED TOO LOW FOR EVEN A CB MENTION. SFC WINDS
WILL REMAIN BREEZY OVERNIGHT. A STRONG COLD FRONT WILL APPROACH
THE AREA VERY LATE IN THE FORECAST PERIOD.
PREV DISCUSSION... /ISSUED 448 AM CDT TUE APR 30 2013/
SHORT TERM...
200 AM CDT SFC ANALYSIS SHOWS A SFC TROUGH EXTENDING SOUTH INTO ERN
NM FROM A LOW PRESSURE CENTER IN THE ERN DAKOTAS. THERE IS ALSO A
COLD FRONT STRETCHING W-SW ACROSS WRN NE INTO SRN WY AND NRN UT THAT
WILL HAVE A BIG IMPACT ON OUR WX TOMORROW. ALOFT...A LONGWAVE TROUGH
LOCATED ACROSS SW CANADA AND NW CONUS WILL SLOWLY PROGRESS EAST AND
AMPLIFY SOMEWHAT EAST OF THE ROCKIES TODAY...WHILE WTX WILL REMAIN
IN A REGION OF OVERALL WEAK FLOW BETWEEN THE NORTHERN SYSTEM AND A
SMALLER LOW MOVING EAST ALONG THE GULF COAST.
DECENT MOISTURE ADVECTION IS UNDERWAY EAST OF THE SFC TROUGH WITH
MID TO UPPER 50 DEWPOINTS ADVANCING INTO THE ROLLING PLAINS. THERE
WILL BE A SHORT WINDOW FOR SOME LIGHT FOG AROUND SUNRISE AS THE
MOISTURE MOVES ONTO THE CAPROCK...BUT NO MAJOR VISIBILITY CONCERNS
ARE EXPECTED AT THIS TIME.
MAIN FCST CONCERN FOR TODAY WILL THE CONVECTIVE CHANCES. THE DRYLINE
IS EXPECTED TO MIX ACROSS THE CAPROCK BY MID AFTERNOON BUT
INCREASINGLY STRONG AND BACKED FLOW ACROSS THE ROLLING PLAINS SHOULD
PUT A STOP TO IT...WITH SOME UNCERTAINTY WHETHER OR NOT THE DRYLINE
WILL SET UP OFF THE CAPROCK EDGE OR PERHAPS HANG FARTHER WEST AS
INDICATED BY THE 0Z NAM. MOISTURE WILL MIX DEEPLY ON BOTH SIDES OF
THE DRYLINE AS TEMPS WARM INTO THE LOWER 90S. FCST SOUNDINGS SUGGEST
THAT THE ATMOSPHERE WILL BECOME UNCAPPED ALONG AND JUST WEST OF THE
DRYLINE WITH ABOUT 1000 J/KG OF ML CAPE ABOVE HIGH LCLS. WHILE WE
EXPECT THE DRYLINE CIRCULATION TO PROVIDE A ADEQUATE LIFTING
MECHANISM FOR LOW-LVL PARCELS...UPPER-LVL SUPPORT LOOKS PRETTY
NEBULOUS. THERE IS A PROGGED SLIGHT INCREASE IN MID-LVL WINDS TO
AROUND 25 KTS...RESULTING IN A MODEST 20 KTS OR SO OF 0-6 KM BULK
SHEAR. HI-RES MODELS ARE DECIDEDLY MIXED WITH THE DEVELOPMENT OF DEEP
CONVECTION IN VICINITY OF THE DRYLINE...WITH ISOLATED COVERAGE AT
BEST. WE WILL HAVE AN ISOLATED MENTION FROM JUST JUST EAST OF THE
I-27/US 87 CORRIDOR THRU THE AFTERNOON...AND SHIFT THE MENTION EAST
IN THE EVENING WITH AN EXPECT SLOW STORM MOTION TO THE SE. ANY T-STORM
ACTIVITY WILL HAVE DIFFICULTY SURVIVING IN THE MORE STABLE AIR EAST
OF THE DRYLINE AND SHOULD DIE FAIRLY QUICKLY AFTER SUNSET. THE SEVERE
THREAT FROM ANY STORMS WILL BE FAIRLY LOW...ISOLATED STRONG WIND
GUSTS WILL BE POSSIBLE WHILE LARGE HAIL LOOKS VERY UNLIKELY.
THE DRYLINE WILL RETREAT SOME THIS EVENING...BUT THEN HALT AS THE
SFC LOW BEGINS TO MOVE SE AND A PRE-FRONTAL TROUGH MOVES INTO THE
WRN ZONES. IT WILL BE VERY MILD OVERNIGHT WITH TEMPS IN THE 50S AND
60S. THE COLD FRONT SHOULD BE ON THE DOORSTEP OF THE SW TX PANHANDLE
BY 12Z WED.
LONG TERM...
PRIMARY FOCUS IN THE EXTENDED FORECAST REVOLVES AROUND THE IMPACTS
BEHIND ANOTHER STRONG LATE SEASON COLD FRONT THAT WILL MOVE THROUGH
ON WEDNESDAY. STRONG NORTH WINDS...MUCH COLDER TEMPERATURES
/INCLUDING THE POSSIBILITY OF ANOTHER FREEZE OR TWO/ AND A BRIEF
WINDOW FOR PRECIPITATION...INCLUDING LIGHT WINTRY PRECIPITATION...ARE
ALL IN THE FORECAST BETWEEN WEDNESDAY NIGHT AND THURSDAY NIGHT.
THE LARGE SCALE PATTERN WILL FEATURE AN AMPLIFYING TROUGH DIGGING
THROUGH THE INTERMOUNTAIN WEST TOMORROW...THEN EMERGING ACROSS THE
HIGH PLAINS ON THURSDAY BEFORE CUTTING OFF FRIDAY SOMEWHERE ACROSS
THE PLAINS. THE CUTOFF LOW IS THEN PROGGED TO GRADUALLY LIFT
NORTHEASTWARD AWAY FROM THE REGION THROUGH THE WEEKEND THOUGH THE
EXACT LATITUDE AT WHICH THIS OCCURS REMAINS VERY UNCERTAIN. ANOTHER
UPPER TROUGH WILL FOLLOW BY THE EARLY TO MIDDLE PARTS OF NEXT WEEK
THOUGH THE DETAILS WITH THIS NEXT SYSTEM WILL BE TOUGH FOR THE NWP
TO RESOLVE GIVEN THE BLOCKY PATTERN.
OF MAIN CONCERN EARLY ON WILL BE ON THE TIMING OF THE COLD FRONT DUE
IN ON WEDNESDAY. IT APPEARS THE INITIAL NORTHERLY WIND SHIFT WILL
ADVANCE FROM NORTH TO SOUTH ACROSS THE SOUTH PLAINS THROUGH THE
MORNING HOURS...THOUGH JUST A COUPLE OF HOURS OF DIFFERENCE IN
TIMING WILL MAKE A HUGE DIFFERENCE IN HOW WARM ANY PARTICULAR
LOCATION GETS. ATTM...WE CONTINUE TO FAVOR A QUICKER
FROPA...RESULTING IN FORECAST HIGHS ON WEDNESDAY RANGING FROM THE
50S AND LOWER 60S NORTHWEST TO MIDDLE 80S SOUTHEAST. THE INITIAL
PRESSURE GRADIENT AND PRESSURE RISES WILL FAVOR GUSTY WINDS
SUSTAINED AT 20-30 MPH...BUT THE GRADIENT IS PROGGED TO FURTHER
TIGHTEN LATE IN THE DAY AND NOT REALLY BEING TO RELAX UNTIL LATER IN
THE DAY ON THURSDAY. THUS...WE COULD SEE A PROLONGED PERIOD OF
ADVISORY LEVEL WINDS LATE WEDNESDAY INTO THURSDAY AND HAVE
INCREASED WIND SPEEDS IN THE GRIDS THROUGH THIS PERIOD. OF
NOTE...THERE IS A SIGNIFICANT DISPARITY BETWEEN THE MET AND MAV
MOS WIND GUIDANCE WITH THE MET ON THE LOW SIDE /AROUND 25 KTS/ AND
THE MAV ON THE HIGH SIDE /ABOVE 40 KTS/. THINK THE MAV IS A BIT
BULLISH...BUT IT WILL BE A WINDY AND RAW STRETCH REGARDLESS.
THESE STRONG WINDS WILL CARRY IN MUCH COLDER AIR /AND BLDU/ WITH
TEMPERATURES BY THURSDAY MORNING EXPECTED TO BREECH THE FREEZING
MARK ACROSS THE NORTHWEST ZONES...WITH 30S FOUND ACROSS MUCH OF
THE REMAINDER OF THE FA...ASIDE FROM A FEW LOWER 40S ACROSS THE
FAR SOUTHEAST ZONES.
REGARDING PRECIPITATION CHANCES...THEY WILL BE ON THE RISE...AT
LEAST POST-FRONTAL. INITIALLY...ALONG THE FRONT...THERE MAY BE A
SLIM CHANCE OF STORMS ACROSS THE FAR EASTERN ZONES WEDNESDAY
AFTERNOON...THOUGH IF THE QUICKER FROPA COMES TO FRUITION THE
WINDOW FOR SFC BASED STORMS WOULD BE NARROWED IF NOT CLOSED
ALTOGETHER. REGARDLESS...DID MAINTAIN A MINIMAL THUNDER MENTION
ACROSS THE FAR EASTERN ZONES WEDNESDAY AFTERNOON. INSTEAD...THE
BETTER PRECIPITATION CHANCES WILL DEVELOP WEDNESDAY NIGHT INTO
EARLY THURSDAY AS FRONTOGENETIC FORCING AND ISENTROPIC UPGLIDE
INCREASE ABOVE THE CAA NEAR/AT THE SFC. ALTHOUGH THE LARGE SCALE
ASCENT FROM THE PASSING TROUGH WILL ONLY GRAZE THE AREA THE
PREVIOUSLY MENTIONED MECHANISMS SHOULD RESULT IN RAIN SHOWERS
DEVELOPING LATE WEDNESDAY NIGHT /AND FAVORING SPOTS OFF THE
CAPROCK/. THERE MAY EVEN BE A LITTLE ELEVATED INSTABILITY IN PLACE
OFF THE CAPROCK WHICH COULD SUPPORT A CHANCE OF THUNDER TOO.
HOWEVER...THE PRIMARY MODE WILL LIKELY BE RAIN SHOWERS EARLY
ON...BUT PRECIPITATION TYPE MAY GET TRICKY AFTER MIDNIGHT AS
COLDER AIR CONTINUES TO POUR IN. PROGGED SOUNDINGS INDICATE A
SIGNIFICANT WARM LAYER CENTERED BETWEEN 700 AND 800 MB...WITH A
LAYER OF SUB-FREEZING TEMPERATURES NEAR 850 MB THAT STRENGTHENS
AND DEEPENS SOUTHWARD ACROSS THE CAPROCK LATE WEDNESDAY NIGHT.
THUS...WE COULD SEE THE RAIN MIX WITH SLEET AND/OR SNOW AS THE
NIGHT GOES ON ACROSS MUCH OF THE CAPROCK...THOUGH ANY WINTRY
PRECIPITATION SHOULD BE ON THE LIGHT SIDE. PRECIPITATION WILL
GRADUALLY WANE THURSDAY MORNING AS THE LOWER AND MID-LEVEL LIFT
WEAKENS...THOUGH IT WILL TAKE AWHILE FOR CLOUDS TO CLEAR AND HIGHS
WILL STRUGGLE TO MAKE IT INTO THE LOWER 50S /IF THEY DO AT ALL/.
CLEARING SKIES AND WEAKENING WINDS WILL THEN SET THE STAGE FOR
ANOTHER COLD NIGHT THURSDAY NIGHT...WITH SPOTS ON THE CAPROCK
LIKELY TO SEE ANOTHER FREEZE...WITH A FROST ALSO POSSIBLE IN THE
ROLLING PLAINS. PLAN TO HIGHLIGHT THE COLDER
TEMPERATURES...POSSIBLE FREEZES AND POTENTIAL FOR LIGHT WINTRY
PRECIPITATION IN A SPECIAL WEATHER STATEMENT.
AFTER FRIDAY MORNING...TEMPERATURES WILL GRADUALLY MODERATE INTO
EARLY NEXT WEEK. SHOWER/STORM CHANCES MAY ALSO IMPROVE TOWARD THE
FAR END OF THE EXTENDED THOUGH CONFIDENCE IN THIS...LIKE THE
PREDICTABILITY OF THE LARGE SCALE WEATHER PATTERN...REMAINS LOW.
HENCE...HAVE MAINTAINED POPS AROUND 10 PERCENT FROM SUNDAY ONWARD.
FIRE WEATHER...
WHILE THERE IS SOME UNCERTAINTY HOW FAR WEST THE DRYLINE WILL SET UP
THIS AFTERNOON...VERY WARM TEMPS AND DRY AIR WILL RESULT IN RH
VALUES DROPPING BELOW 10 PERCENT ACROSS MUCH OF THE FAR SW TX
PANHANDLE AND WRN SPLNS. WIND SPEEDS WILL NOT BE VERY
STRONG...HOWEVER THEY SHOULD BE IN THE 10 TO 20 MPH RANGE AT THE 20
FOOT LEVEL SUFFICIENT FOR THE ISSUANCE OF A FIRE DANGER STATEMENT.
THIS AREA IS LIKELY TO REMAIN DRY WELL IN TO THE EVENING HOURS...BUT
WIND SPEEDS WILL BE LIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 91 50 58 29 50 / 0 10 10 20 10
TULIA 91 54 60 31 51 / 10 10 10 30 20
PLAINVIEW 90 56 65 32 51 / 10 10 10 30 20
LEVELLAND 92 55 71 33 51 / 10 10 10 30 20
LUBBOCK 92 60 71 34 51 / 10 10 10 30 20
DENVER CITY 91 55 82 34 52 / 0 10 10 30 20
BROWNFIELD 92 55 80 34 52 / 10 10 10 30 20
CHILDRESS 93 62 74 39 53 / 10 20 10 50 30
SPUR 91 62 80 37 53 / 20 20 10 40 30
ASPERMONT 93 64 83 41 52 / 10 10 20 50 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
200 PM EDT TUE APR 30 2013
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL PERSIST THROUGH
THE WEEK TO BRING COOL AND CLOUDY CONDITIONS. AN AREA OF LOW
PRESSURE WILL DEVELOP AND LINGER OVER THE GREAT PLAINS...WHICH
COULD AFFECT THE EASTERN UNITED STATES LATE IN THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1215 PM EDT TUESDAY...
MORE BREAKS IN THE CLOUDINESS ARE APPEARING WEST OF THE BLUE
RIDGE...EXCEPT NEAR BOONE NORTH CAROLINA. TEMPERATURES WERE
ADJUSTED DOWNWARD DUE TO THE CONTINUING LOW CLOUDS IN THIS AREA.
LITTLE IF ANY CHANGE HAS BEEN SEEN ON VISIBLE SATELLITE ELSEWHERE.
THE LATEST NAM AND GFS GUIDANCE STILL SHOWS A SMALL AMOUNT OF QPF
ALONG THE WESTERN EDGE OF THE WEDGE...SO THE SLIGHT CHANCE TO
CHANCE POPS WERE HELD IN PLACE. OTHERWISE...NO OTHER SIGNIFICANT
TWEAKS WERE MADE FOR THIS UPDATE.
AS OF 1010 AM EDT TUESDAY...
THE LATEST 12Z RNK SOUNDING SHOWS BOUNDARY LAYER MOISTURE STILL
IN PLACE...BUT IT HAS BECOME SHALLOWER DURING THE PAST 24 HOURS.
THICK CLOUD COVER STILL HOLDS OVER THE PIEDMONT...BUT A FEW BREAKS
ARE SHOWING IN FAR SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA.
SOME INSOLATION SHOULD ALLOW HIGH TEMPERATURES TO AT LEAST REACH
THE VALUES REALIZED YESTERDAY. TEMPERATURES WERE STILL HELD ON THE
COOLER SIDE OF GUIDANCE BUT NOT QUITE AS MUCH IN THIS UPDATE.
ALSO...SLIGHT CHANCE POPS WERE EXPANDED A LITTLE MORE ON THE
WESTERN PERIPHERY OF THE WEDGE GIVEN THE LATEST RAP MODEL
SOLUTION. HOWEVER...THERE IS NO INSTABILITY THAT WOULD SUPPORT
MENTION OF THUNDER BASED ON THE MODEL SOUNDINGS...SO JUST LIGHT
RAIN SHOWERS WERE INCLUDED.
BY TONIGHT...THE POTENTIAL FOR LOW CLOUDS AND FOG SHOULD EMERGE
AGAIN OVER THE CWA. WITH AN AREA OF LOW PRESSURE DEVELOPING
ALONG THE SOUTHEAST COAST...AND HIGH PRESSURE REMAINING FIRM OVER
THE NORTHEAST...THE EASTERLY FLOW COULD BE ENHANCED AND FURTHER
STRENGTHEN THE COOL WEDGE. ALTHOUGH POPS WERE KEPT LOW DURING THIS
PERIOD...SOME DRIZZLE IS CERTAINLY POSSIBLE...ESPECIALLY ALONG THE
EASTERN SIDE OF THE BLUE RIDGE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
RIDGING...SITUATED ROUGHLY ALONG THE APPALACHIAN CHAIN...WILL BE THE
DOMINANT FEATURE IN THE UPPER LEVELS FOR THE REMAINDER OF THE
WORKWEEK AS A DEEP UPPER LEVEL TROUGH SINKS SOUTHWARD ACROSS THE
ROCKIES...AND EVENTUALLY PINCHES OFF INTO A CLOSED LOW OVER THE
CENTRAL PLAINS ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL REMAIN
WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE
WEEKEND...RESULTING IN A PERSISTENT NORTHEASTERLY TO EASTERLY WIND
FLOW ACROSS THE AREA THAT WILL CONTINUE TO DRAW COOL MOIST AIR
FROM THE ATLANTIC.
AS SUCH...WE CAN EXPECT SIMILAR WEATHER CONDITIONS EACH DAY THROUGH
THE PERIOD...WITH PATCHY DENSE FOG AND AREAS OF DRIZZLE DEVELOPING
EARLY EACH MORNING...ESPECIALLY ALONG THE BLUE RIDGE AND THE EASTERN
FACES OF OTHER PROMINENT RIDGES. MORNING FOG AND LOW CLOUDS WILL
BURN OFF WITH AFTERNOON HEATING...MAKING FOR PARTLY TO MOSTLY CLOUDY
SKIES DURING EACH AFTERNOON. MAY SEE A FEW SHOWERS DEVELOP EACH
AFTERNOON AND EVENING AS SUBTLE DISTURBANCES RIDE ALONG THE EDGE OF
THE UPPER RIDGE. SHOWER ACTIVITY MAY BE ENHANCED BY THE OROGRAPHIC
LIFT OF EASTERLY FLOW INTO THE MOUNTAINS...BUT OTHERWISE DO NOT SEE
ANY SPECIFIC FEATURE THAT WILL CAUSE ORGANIZED RAINFALL. ANY SHOWER
ACTIVITY WILL DIMINISH DURING LATE EVENING AS DAYTIME HEATING
ENDS...WITH A REDEVELOPMENT OF LOW CLOUDS AND PATCHY FOG/DRIZZLE
LATER IN THE OVERNIGHT.
THE FLOW OFF OF THE ATLANTIC WILL MAINTAIN SLIGHTLY COOL CONDITIONS
FOR MUCH OF THE AREA...WITH AFTERNOON HIGHS SOME 3 TO 5 DEGREES
BELOW NORMAL EACH DAY...GENERALLY REACHING INTO THE MID TO UPPER
60S. PORTIONS OF THE MOUNTAIN EMPIRE AND SOUTHEAST WEST VIRGINIA...
LOCATIONS AT THE VERY EDGE OF THE HIGH PRESSURE WEDGE...ARE EXPECTED
TO BE CLOSE TO NORMAL FOR HIGHS. MORNING LOWS WILL BE IN THE UPPER
40S TO LOW 50S WEDNESDAY AND THURSDAY NIGHT...BUT WILL DIP COOLER
FRIDAY NIGHT AS THE UPPER RIDGE BEGINS TO BREAK DOWN...AND WILL
THEREFORE FALL INTO THE LOW 40S NORTH TO UPPER 40S SOUTH.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 258 PM EDT MONDAY...
THE GYRE OVER THE CANADIAN MARITIMES WILL EVENTUALLY ERODE THE OMEGA
BLOCK INTO A REX...AS A PIECE OF THIS VORTEX WILL ACTUALLY BREAK
FREE AND HEAD SOUTHWEST. NONETHELESS EXPECT SIMILAR WEDGE CONDS
THROUGH THE WEEKEND. THE ECMWF/GFS HAVE HAD A DIFFICULT TIME
RESOLVING AN UPPER DISTURBANCE CROSSING THE LOWER MISSISSIPPI RIVER
VALLEY EARLY NEXT WEEK. THE 12Z GFS WANTS TO BRING THIS SYSTEM
ACROSS THE MOUNTAINS AND INTO THE MID ATLANTIC...WHEREAS THE ECMWF
IS MORE NORTH AND WEST WITH ITS TRACK. IT DOES APPEAR AS THOUGH THIS
STRONG UPPER LOW WILL FINALLY BREAK DOWN THE STRONG UPPER
HIGH...LEADING TO A WARMUP WITH MORE SUNSHINE FINALLY NEXT WEEK.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 200 PM EDT TUESDAY...
FLYING CONDITIONS HAVE SLIGHTLY IMPROVED DURING THE DAY...AS
CEILINGS HAVE RISEN TOWARD MVFR FOR MOST SITES...AND EVEN TO VFR
AT LWB AND BLF. THERE IS ENOUGH CONFIDENCE THAT THIS PATTERN WILL
HOLD THROUGH THIS AFTERNOON...ALTHOUGH SOME FLUCTUATIONS IN
CEILINGS ARE POSSIBLE. EAST TO SOUTHEAST WINDS WILL PUMP MORE
MARINE MOISTURE INTO THE BOUNDARY LAYER TONIGHT. ALL MODEL
GUIDANCE SHOWS HIGH PRESSURE OFFSHORE OF THE NEW ENGLAND
STATES...AND A DEVELOPING LOW PRESSURE AREA OVER THE SOUTHEAST
COAST...WHICH WILL ACT TOGETHER TO ENHANCE THE EXISTING COOL
WEDGE. AS A RESULT...IT APPEARS THERE IS HIGH CONFIDENCE OF MORE
LIFR/IFR CEILINGS AND VISIBILITIES...WITH THE WORST CONDITIONS
EXPECTED DURING EARLY WEDNESDAY MORNING. CEILINGS SHOULD GRADUALLY
IMPROVE TO MVFR LATE IN THE MORNING ONCE ENOUGH DAYTIME HEATING
AND BOUNDARY LAYER MIXING CAN OCCUR.
THE PERSISTENT COOL WEDGE SHOULD CONTINUE TO HOLD THROUGH
THURSDAY...WITH MORE LIFR/IFR CONDITIONS POSSIBLE DURING THE
NIGHT...AND SLOW IMPROVEMENT TO MVFR IN THE DAY. BY FRIDAY...THE
MODELS HINT THAT HIGH PRESSURE MAY BUILD OVERHEAD TO ALLOW A
DRIER NORTHEAST WIND THAT WOULD SLOWLY ERODE THE WEDGE...AND
BRING BETTER FLYING WEATHER BY THE END OF THIS WEEK. MEANWHILE...A
LOW PRESSURE SYSTEM OVER THE GREAT PLAINS WILL SLOWLY ARRIVE FROM
THE WEST. THE TRACK OF THIS SYSTEM AND ANY IMPACT TO THE TAF
SITES THIS WEEKEND IS QUITE LOW IN CONFIDENCE...DUE TO MAJOR
DIFFERENCES IN THE GFS AND ECMWF SOLUTIONS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...NF
LONG TERM...KM
AVIATION...PW
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1217 PM EDT TUE APR 30 2013
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL PERSIST THROUGH
THE WEEK TO BRING COOL AND CLOUDY CONDITIONS. AN AREA OF LOW
PRESSURE WILL DEVELOP AND LINGER OVER THE GREAT PLAINS...WHICH
COULD AFFECT THE EASTERN UNITED STATES LATE IN THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1215 PM EDT TUESDAY...
MORE BREAKS IN THE CLOUDINESS ARE APPEARING WEST OF THE BLUE
RIDGE...EXCEPT NEAR BOONE NORTH CAROLINA. TEMPERATURES WERE
ADJUSTED DOWNWARD DUE TO THE CONTINUING LOW CLOUDS IN THIS AREA.
LITTLE IF ANY CHANGE HAS BEEN SEEN ON VISIBLE SATELLITE ELSEWHERE.
THE LATEST NAM AND GFS GUIDANCE STILL SHOWS A SMALL AMOUNT OF QPF
ALONG THE WESTERN EDGE OF THE WEDGE...SO THE SLIGHT CHANCE TO
CHANCE POPS WERE HELD IN PLACE. OTHERWISE...NO OTHER SIGNIFICANT
TWEAKS WERE MADE FOR THIS UPDATE.
AS OF 1010 AM EDT TUESDAY...
THE LATEST 12Z RNK SOUNDING SHOWS BOUNDARY LAYER MOISTURE STILL
IN PLACE...BUT IT HAS BECOME SHALLOWER DURING THE PAST 24 HOURS.
THICK CLOUD COVER STILL HOLDS OVER THE PIEDMONT...BUT A FEW BREAKS
ARE SHOWING IN FAR SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA.
SOME INSOLATION SHOULD ALLOW HIGH TEMPERATURES TO AT LEAST REACH
THE VALUES REALIZED YESTERDAY. TEMPERATURES WERE STILL HELD ON THE
COOLER SIDE OF GUIDANCE BUT NOT QUITE AS MUCH IN THIS UPDATE.
ALSO...SLIGHT CHANCE POPS WERE EXPANDED A LITTLE MORE ON THE
WESTERN PERIPHERY OF THE WEDGE GIVEN THE LATEST RAP MODEL
SOLUTION. HOWEVER...THERE IS NO INSTABILITY THAT WOULD SUPPORT
MENTION OF THUNDER BASED ON THE MODEL SOUNDINGS...SO JUST LIGHT
RAIN SHOWERS WERE INCLUDED.
BY TONIGHT...THE POTENTIAL FOR LOW CLOUDS AND FOG SHOULD EMERGE
AGAIN OVER THE CWA. WITH AN AREA OF LOW PRESSURE DEVELOPING
ALONG THE SOUTHEAST COAST...AND HIGH PRESSURE REMAINING FIRM OVER
THE NORTHEAST...THE EASTERLY FLOW COULD BE ENHANCED AND FURTHER
STRENGTHEN THE COOL WEDGE. ALTHOUGH POPS WERE KEPT LOW DURING THIS
PERIOD...SOME DRIZZLE IS CERTAINLY POSSIBLE...ESPECIALLY ALONG THE
EASTERN SIDE OF THE BLUE RIDGE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
RIDGING...SITUATED ROUGHLY ALONG THE APPALACHIAN CHAIN...WILL BE THE
DOMINANT FEATURE IN THE UPPER LEVELS FOR THE REMAINDER OF THE
WORKWEEK AS A DEEP UPPER LEVEL TROUGH SINKS SOUTHWARD ACROSS THE
ROCKIES...AND EVENTUALLY PINCHES OFF INTO A CLOSED LOW OVER THE
CENTRAL PLAINS ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL REMAIN
WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE
WEEKEND...RESULTING IN A PERSISTENT NORTHEASTERLY TO EASTERLY WIND
FLOW ACROSS THE AREA THAT WILL CONTINUE TO DRAW COOL MOIST AIR FROM
THE ATLANTIC.
AS SUCH...WE CAN EXPECT SIMILAR WEATHER CONDITIONS EACH DAY THROUGH
THE PERIOD...WITH PATCHY DENSE FOG AND AREAS OF DRIZZLE DEVELOPING
EARLY EACH MORNING...ESPECIALLY ALONG THE BLUE RIDGE AND THE EASTERN
FACES OF OTHER PROMINENT RIDGES. MORNING FOG AND LOW CLOUDS WILL
BURN OFF WITH AFTERNOON HEATING...MAKING FOR PARTLY TO MOSTLY CLOUDY
SKIES DURING EACH AFTERNOON. MAY SEE A FEW SHOWERS DEVELOP EACH
AFTERNOON AND EVENING AS SUBTLE DISTURBANCES RIDE ALONG THE EDGE OF
THE UPPER RIDGE. SHOWER ACTIVITY MAY BE ENHANCED BY THE OROGRAPHIC
LIFT OF EASTERLY FLOW INTO THE MOUNTAINS...BUT OTHERWISE DO NOT SEE
ANY SPECIFIC FEATURE THAT WILL CAUSE ORGANIZED RAINFALL. ANY SHOWER
ACTIVITY WILL DIMINISH DURING LATE EVENING AS DAYTIME HEATING
ENDS...WITH A REDEVELOPMENT OF LOW CLOUDS AND PATCHY FOG/DRIZZLE
LATER IN THE OVERNIGHT.
THE FLOW OFF OF THE ATLANTIC WILL MAINTAIN SLIGHTLY COOL CONDITIONS
FOR MUCH OF THE AREA...WITH AFTERNOON HIGHS SOME 3 TO 5 DEGREES
BELOW NORMAL EACH DAY...GENERALLY REACHING INTO THE MID TO UPPER
60S. PORTIONS OF THE MOUNTAIN EMPIRE AND SOUTHEAST WEST VIRGINIA...
LOCATIONS AT THE VERY EDGE OF THE HIGH PRESSURE WEDGE...ARE EXPECTED
TO BE CLOSE TO NORMAL FOR HIGHS. MORNING LOWS WILL BE IN THE UPPER
40S TO LOW 50S WEDNESDAY AND THURSDAY NIGHT...BUT WILL DIP COOLER
FRIDAY NIGHT AS THE UPPER RIDGE BEGINS TO BREAK DOWN...AND WILL
THEREFORE FALL INTO THE LOW 40S NORTH TO UPPER 40S SOUTH.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 258 PM EDT MONDAY...
THE GYRE OVER THE CANADIAN MARITIMES WILL EVENTUALLY ERODE THE OMEGA
BLOCK INTO A REX...AS A PIECE OF THIS VORTEX WILL ACTUALLY BREAK
FREE AND HEAD SOUTHWEST. NONETHELESS EXPECT SIMILAR WEDGE CONDS
THROUGH THE WEEKEND. THE ECMWF/GFS HAVE HAD A DIFFICULT TIME
RESOLVING AN UPPER DISTURBANCE CROSSING THE LOWER MISSISSIPPI RIVER
VALLEY EARLY NEXT WEEK. THE 12Z GFS WANTS TO BRING THIS SYSTEM
ACROSS THE MOUNTAINS AND INTO THE MID ATLANTIC...WHEREAS THE ECMWF
IS MORE NORTH AND WEST WITH ITS TRACK. IT DOES APPEAR AS THOUGH THIS
STRONG UPPER LOW WILL FINALLY BREAK DOWN THE STRONG UPPER
HIGH...LEADING TO A WARMUP WITH MORE SUNSHINE FINALLY NEXT WEEK.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
AS OF 740 AM EDT TUESDAY...
POOR AVIATION CONDITIONS EXPECTED TO PERSIST THROUGH TAF VALID
PERIOD AS A MID-ATLANTIC SFC HIGH PERSISTS WITH A COOL...EASTERLY
MARITIME FLOW INTO THE CWA. ANY EROSION OF THE WEDGE DURING
DIURNAL HEATING WILL FILL BACK IN OVERNIGHT...WITH PERHAPS EVEN A
BETTER SURGE TONIGHT AS COMPARED TO THIS MORNING AS THE CRUX OF
THE MARITIME AIR MASS SETTLES ACROSS THE REGION. EXPECT IFR-LIFR
CIGS AND MOSTLY MVFR-OCCASIONALLY IFR VSBYS TO PREVAIL AT MANY OF
THE TAF SITES THROUGH MID-MORNING...WITH IMPROVEMENT ONLY TO MVFR
CIGS AT BEST 15Z-04Z. VSBYS SHOULD IMPROVE TO VFR AT MOST SITES AS
THE CIGS LIFT INTO THE MVFR CATEGORY...BEFORE CONDITIONS
DETERIORATE AFTER MIDNIGHT BACK TO IFR-LIFR CIGS AND MVFR-IFR
VSBYS AGAIN. THE EXCEPTION WILL BE BLF...WHICH WILL REMAIN ON THE
PERIPHERY OF THE WEDGE AND WILL HAVE LESS POTENTIAL FOR IFR/LIFR
CIGS/VSBYS THROUGH THIS TAF VALID PERIOD. WINDS WILL REMAIN NE-E
5-8KTS THROUGH THE TAF VALID PERIOD...WITH LOW END GUSTS POSSIBLE
15Z-22Z LYH AND DAN. ANY TSRA SHOULD REMAIN WEST OF THE CWA AND
NOT AFFECT ANY OF THE RNK TAF SITES.
EXTENDED AVIATION DISCUSSION...PERHAPS SLIGHTLY IMPROVED AVIATION
CONDITIONS BY THE END OF THE WEEK INTO THE FIRST HALF OF THE
WEEKEND WITH ENOUGH DRYING FROM THE NE TO ALLOW FOR A BRIEF RETURN
TO VFR FOR THURSDAY INTO FRIDAY...IF THE SFC AND UPPER HIGH CAN
MOVE OVERHEAD. THIS WILL SHUNT THE DEEPER MOISTURE INTO THE SE
STATES. RETURN FLOW SHOULD BRING MOISTURE BACK NORTH BY SATURDAY
OR SUNDAY AHEAD OF A VERY SLOW MOVING OCCLUDED FRONT/CLOSED UPPER
LOW TO THE WEST. THIS MAY RESULT IN A RETURN OR CONTINUATION OF
MVFR CIGS...BUT CONSIDERABLE MODEL RUN-TO-RUN CONSISTENCY DOES NOT
ALLOW FOR MUCH RELIABILITY IN FORECAST CONDITIONS THAT FAR OUT AT
THIS TIME.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...NF
LONG TERM...KM
AVIATION...RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1012 AM EDT TUE APR 30 2013
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL PERSIST THROUGH
THE WEEK TO BRING COOL AND CLOUDY CONDITIONS. AN AREA OF LOW
PRESSURE WILL DEVELOP AND LINGER OVER THE GREAT PLAINS...WHICH
COULD AFFECT THE EASTERN UNITED STATES LATE IN THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EDT TUESDAY...
THE LATEST 12Z RNK SOUNDING SHOWS BOUNDARY LAYER MOISTURE STILL
IN PLACE...BUT IT HAS BECOME SHALLOWER DURING THE PAST 24 HOURS.
THICK CLOUD COVER STILL HOLDS OVER THE PIEDMONT...BUT A FEW BREAKS
ARE SHOWING IN FAR SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA.
SOME INSOLATION SHOULD ALLOW HIGH TEMPERATURES TO AT LEAST REACH
THE VALUES REALIZED YESTERDAY. TEMPERATURES WERE STILL HELD ON THE
COOLER SIDE OF GUIDANCE BUT NOT QUITE AS MUCH IN THIS UPDATE.
ALSO...SLIGHT CHANCE POPS WERE EXPANDED A LITTLE MORE ON THE
WESTERN PERIPHERY OF THE WEDGE GIVEN THE LATEST RAP MODEL
SOLUTION. HOWEVER...THERE IS NO INSTABILITY THAT WOULD SUPPORT
MENTION OF THUNDER BASED ON THE MODEL SOUNDINGS...SO JUST LIGHT
RAIN SHOWERS WERE INCLUDED.
BY TONIGHT...THE POTENTIAL FOR LOW CLOUDS AND FOG SHOULD EMERGE
AGAIN OVER THE CWA. WITH AN AREA OF LOW PRESSURE DEVELOPING
ALONG THE SOUTHEAST COAST...AND HIGH PRESSURE REMAINING FIRM OVER
THE NORTHEAST...THE EASTERLY FLOW COULD BE ENHANCED AND FURTHER
STRENGTHEN THE COOL WEDGE. ALTHOUGH POPS WERE KEPT LOW DURING THIS
PERIOD...SOME DRIZZLE IS CERTAINLY POSSIBLE...ESPECIALLY ALONG THE
EASTERN SIDE OF THE BLUE RIDGE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
RIDGING...SITUATED ROUGHLY ALONG THE APPALACHIAN CHAIN...WILL BE THE
DOMINANT FEATURE IN THE UPPER LEVELS FOR THE REMAINDER OF THE
WORKWEEK AS A DEEP UPPER LEVEL TROUGH SINKS SOUTHWARD ACROSS THE
ROCKIES...AND EVENTUALLY PINCHES OFF INTO A CLOSED LOW OVER THE
CENTRAL PLAINS ON FRIDAY. MEANWHILE...HIGH PRESSURE WILL REMAIN
WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS INTO THE
WEEKEND...RESULTING IN A PERSISTENT NORTHEASTERLY TO EASTERLY WIND
FLOW ACROSS THE AREA THAT WILL CONTINUE TO DRAW COOL MOIST AIR FROM
THE ATLANTIC.
AS SUCH...WE CAN EXPECT SIMILAR WEATHER CONDITIONS EACH DAY THROUGH
THE PERIOD...WITH PATCHY DENSE FOG AND AREAS OF DRIZZLE DEVELOPING
EARLY EACH MORNING...ESPECIALLY ALONG THE BLUE RIDGE AND THE EASTERN
FACES OF OTHER PROMINENT RIDGES. MORNING FOG AND LOW CLOUDS WILL
BURN OFF WITH AFTERNOON HEATING...MAKING FOR PARTLY TO MOSTLY CLOUDY
SKIES DURING EACH AFTERNOON. MAY SEE A FEW SHOWERS DEVELOP EACH
AFTERNOON AND EVENING AS SUBTLE DISTURBANCES RIDE ALONG THE EDGE OF
THE UPPER RIDGE. SHOWER ACTIVITY MAY BE ENHANCED BY THE OROGRAPHIC
LIFT OF EASTERLY FLOW INTO THE MOUNTAINS...BUT OTHERWISE DO NOT SEE
ANY SPECIFIC FEATURE THAT WILL CAUSE ORGANIZED RAINFALL. ANY SHOWER
ACTIVITY WILL DIMINISH DURING LATE EVENING AS DAYTIME HEATING
ENDS...WITH A REDEVELOPMENT OF LOW CLOUDS AND PATCHY FOG/DRIZZLE
LATER IN THE OVERNIGHT.
THE FLOW OFF OF THE ATLANTIC WILL MAINTAIN SLIGHTLY COOL CONDITIONS
FOR MUCH OF THE AREA...WITH AFTERNOON HIGHS SOME 3 TO 5 DEGREES
BELOW NORMAL EACH DAY...GENERALLY REACHING INTO THE MID TO UPPER
60S. PORTIONS OF THE MOUNTAIN EMPIRE AND SOUTHEAST WEST VIRGINIA...
LOCATIONS AT THE VERY EDGE OF THE HIGH PRESSURE WEDGE...ARE EXPECTED
TO BE CLOSE TO NORMAL FOR HIGHS. MORNING LOWS WILL BE IN THE UPPER
40S TO LOW 50S WEDNESDAY AND THURSDAY NIGHT...BUT WILL DIP COOLER
FRIDAY NIGHT AS THE UPPER RIDGE BEGINS TO BREAK DOWN...AND WILL
THEREFORE FALL INTO THE LOW 40S NORTH TO UPPER 40S SOUTH.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 258 PM EDT MONDAY...
THE GYRE OVER THE CANADIAN MARITIMES WILL EVENTUALLY ERODE THE OMEGA
BLOCK INTO A REX...AS A PIECE OF THIS VORTEX WILL ACTUALLY BREAK
FREE AND HEAD SOUTHWEST. NONETHELESS EXPECT SIMILAR WEDGE CONDS
THROUGH THE WEEKEND. THE ECMWF/GFS HAVE HAD A DIFFICULT TIME
RESOLVING AN UPPER DISTURBANCE CROSSING THE LOWER MISSISSIPPI RIVER
VALLEY EARLY NEXT WEEK. THE 12Z GFS WANTS TO BRING THIS SYSTEM
ACROSS THE MOUNTAINS AND INTO THE MID ATLANTIC...WHEREAS THE ECMWF
IS MORE NORTH AND WEST WITH ITS TRACK. IT DOES APPEAR AS THOUGH THIS
STRONG UPPER LOW WILL FINALLY BREAK DOWN THE STRONG UPPER
HIGH...LEADING TO A WARMUP WITH MORE SUNSHINE FINALLY NEXT WEEK.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AS OF 740 AM EDT TUESDAY...
POOR AVIATION CONDITIONS EXPECTED TO PERSIST THROUGH TAF VALID
PERIOD AS A MID-ATLANTIC SFC HIGH PERSISTS WITH A COOL...EASTERLY
MARITIME FLOW INTO THE CWA. ANY EROSION OF THE WEDGE DURING
DIURNAL HEATING WILL FILL BACK IN OVERNIGHT...WITH PERHAPS EVEN A
BETTER SURGE TONIGHT AS COMPARED TO THIS MORNING AS THE CRUX OF
THE MARITIME AIR MASS SETTLES ACROSS THE REGION. EXPECT IFR-LIFR
CIGS AND MOSTLY MVFR-OCCASIONALLY IFR VSBYS TO PREVAIL AT MANY OF
THE TAF SITES THROUGH MID-MORNING...WITH IMPROVEMENT ONLY TO MVFR
CIGS AT BEST 15Z-04Z. VSBYS SHOULD IMPROVE TO VFR AT MOST SITES AS
THE CIGS LIFT INTO THE MVFR CATEGORY...BEFORE CONDITIONS
DETERIORATE AFTER MIDNIGHT BACK TO IFR-LIFR CIGS AND MVFR-IFR
VSBYS AGAIN. THE EXCEPTION WILL BE BLF...WHICH WILL REMAIN ON THE
PERIPHERY OF THE WEDGE AND WILL HAVE LESS POTENTIAL FOR IFR/LIFR
CIGS/VSBYS THROUGH THIS TAF VALID PERIOD. WINDS WILL REMAIN NE-E
5-8KTS THROUGH THE TAF VALID PERIOD...WITH LOW END GUSTS POSSIBLE
15Z-22Z LYH AND DAN. ANY TSRA SHOULD REMAIN WEST OF THE CWA AND
NOT AFFECT ANY OF THE RNK TAF SITES.
EXTENDED AVIATION DISCUSSION...PERHAPS SLIGHTLY IMPROVED AVIATION
CONDITIONS BY THE END OF THE WEEK INTO THE FIRST HALF OF THE
WEEKEND WITH ENOUGH DRYING FROM THE NE TO ALLOW FOR A BRIEF RETURN
TO VFR FOR THURSDAY INTO FRIDAY...IF THE SFC AND UPPER HIGH CAN
MOVE OVERHEAD. THIS WILL SHUNT THE DEEPER MOISTURE INTO THE SE
STATES. RETURN FLOW SHOULD BRING MOISTURE BACK NORTH BY SATURDAY
OR SUNDAY AHEAD OF A VERY SLOW MOVING OCCLUDED FRONT/CLOSED UPPER
LOW TO THE WEST. THIS MAY RESULT IN A RETURN OR CONTINUATION OF
MVFR CIGS...BUT CONSIDERABLE MODEL RUN-TO-RUN CONSISTENCY DOES NOT
ALLOW FOR MUCH RELIABILITY IN FORECAST CONDITIONS THAT FAR OUT AT
THIS TIME.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...NF
LONG TERM...KM
AVIATION...RAB
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
727 PM CDT WED MAY 1 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
WILL BE UPDATING ZONES THIS HOUR TO SLOW ADVANCE OF PCPN EAST. NO
REAL CHANGE TO AREAS UNDER HEADLINES. POSSIBLE MIX ONGOING OVER
MANITOWISH WATERS ATTM. RAP SOUNDINGS TONIGHT IWD...CONTINUE TO SUGGEST
RAIN OR SNOW THIS EVENING...THEN SNOW LATE EVENING/OVERNIGHT.
.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 255 PM CDT WED MAY 1 2013
PLENTY OF ISSUES TO DEAL WITH OVER THE NEXT 24 HOURS AS PARTS OF
NE WI TO RESIDE ON THE ERN FRINGE OF A DECENT LATE SPRING SNOW
STORM. TRYING TO DETERMINE PCPN TYPE AND EXACT SNOW AMOUNTS REMAIN
THE MAIN SHORT-TERM CONCERN.
THE 19Z MSAS SFC ANALYSIS SHOWED A STALLED CDFNT EXTENDED FROM NRN
LWR MI SWWD THRU CNTRL SECTIONS OF MO. LOOKING AT THE LATEST VSBL
SATL IMAGERY...THE MAIN CLOUD BAND TRAILED BY A GOOD 200 MILES AND
WAS SITUATED ALONG AN 8H BOUNDARY DRAPED FROM WRN SECTIONS OF UPR
MI SWWD TO WRN IA. THE RADAR MOSAIC INDICATED A NARROW LINE OF
PCPN ON THE WEST SIDE OF THIS BOUNDARY.
MDLS CONT TO FOCUS PCPN ALONG/BEHIND THIS 8H BOUNDARY WHICH WL
REMAIN NEARLY STATIONARY FROM N-CNTRL WI SWWD THRU WRN IA TNGT.
AXIS OF HEAVIER PCPN AIDED BY STRONG FRONTOGENETICAL FORCING AND
MOISTURE CONVERGENCE...THUS A POTENTIAL 0.25-0.50" OF LIQUID MAY
FALL OVER N-CNTRL/CNTRL WI TNGT. MAIN CONCERN CONTS TO BE PCPN
TYPE MAINLY AFTER MIDNGT AS 8H TEMPS DROP TO AROUND 0C ADN WET-BULB
TEMPS APPROACH CRITICAL THRESHOLDS. ANTICIPATE SNOW TO BEGIN MIXING
WITH THE RAIN OVER N-CNTRL WI BY MID TO LATE EVENING AND TRANSITION
MORE TO SNOW TOWARD DAYBREAK. THE NW CORNER OF VILAS CNTY COULD SEE
AROUND AN INCH OF SLUSHY ACCUMULATION ON GRASSY SURFACES WITH
LESSER AMOUNTS FARTHER SOUTH AND EAST. PCPN CHCS DIMINISH AS ONE
GOES FARTHER EAST WITH ONLY LOW CHC POPS BY THE TIME YOU GET TO THE
LAKESHORE COUNTIES.
PCPN CHCS WL INCREASE ACROSS THE FCST AREA ON THU AS THE 8H
BOUNDARY SLOWLY EDGES EWD. WHILE MOST OF THE PCPN WL FALL AS ALL
RAIN...N-CNTRL WI SHOULD STILL BE MORE SNOW THAN RAIN THRU MOST OF
THE MORNING BEFORE BECOMING MORE OF A PURE RAIN/SNOW MIX IN THE
AFTERNOON AS THE 8H 0C ISOTHERM RETROGRADES WEST AND SLIGHTLY
WARMER AIR ARRIVES. ADDITIONAL SNOW ACCUMULATIONS OVER NW VILAS
COUNTY COULD REACH 2 TO 4 INCHES WHICH WOULD BRING TOTALS INTO THE
3 TO 5 INCH RANGE (MAINLY ON GRASSY SURFACES). AFTER COLLABORATION
WITH DLH AND MQT...HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY
FOR VILAS COUNTY STARTING AT 06Z TNGT AND ENDING AT 18Z THU. WL
PROBABLY ALSO ISSUE A SPS FOR ONEIDA/LINCOLN COUNTIES SINCE WRN
SECTIONS OF THESE COUNTIES COULD SEE 1 TO 3 INCHES OF SNOW. MAX
TEMPS FOR THU TO BE VERY UN-MAY-LIKE...ESPECIALLY OVER NRN AND
CNTRL WI WHERE VALUES TO BE A GOOD 20 DEGREES BELOW NORMAL.
.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 255 PM CDT WED MAY 1 2013
THE PROSPECT OF SNOW...SLEET AND FREEZING RAIN OVER
NORTHCENTRAL WISCONSIN THURSDAY NIGHT AND FRIDAY MORNING ARE
PROBABLY THE PRIMARY FORECAST CHALLENGES THIS PERIOD. THE MEDIUM
RANGE MODELS FORECAST TEMPERATURES COLD ENOUGH FOR SNOW OR SLEET
IN FAR NORTHCENTRAL WISCONSIN THURSDAY EVENING THEN WARMER AIR
AROUND 850MB ROTATES AROUND FROM THE EAST OVERNIGHT AND SHOULD
RESULT IN A CHANGE TO SLEET OR FREEZING RAIN. NOT SURE HOW MUCH
TROUBLE THE SLEET OR FREEZING RAIN WILL CAUSE AS ROAD SURFACES
HAVE WARMED OVER THE LAST FEW DAYS BUT THERE COULD BE FREEZING
RAIN ON TREES AND POWER LINES. MIGHT NEED A WINTER WEATHER
ADVISORY AGAIN FOR THAT AREA. ELSEWHERE A COLD RAIN EXPECTED WITH
PERHAPS SOME SLEET MIXED IN THE THE NORTHEAST.
THE MODELS FORECAST THE FORMATION OF CUTOFF LOW FRIDAY MORNING
WHICH THEN DRIFTS SLOWLY EAST INTO TENNESSEE OR KENTUCKY BY SUNDAY
EVENING. THIS IS FAR ENOUGH TO THE SOUTH TO ALLOW FOR WEAK RIDGING
ACROSS THE AREA BY SATURDAY AFTERNOON. SO EXPECT THAT PERIODS OF
RAIN FRIDAY AND FRIDAY NIGHT WILL DIMINISH SATURDAY MORNING WITH
MOSTLY DRY AND SEASONABLE WEATHER FOR SATURDAY AFTERNOON AND
SUNDAY. THE RAIN AND MELTING SNOW IN NORTHERN WISCONSIN WILL
LIKELY KEEP RIVERS AND STREAMS HIGH FOR THE NEXT SEVERAL DAYS AND
THERE MAY BE SOME NEW RIVER FLOOD WARNINGS DEPENDING ON RAINFALL
AMOUNTS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 714 PM CDT WED MAY 1 2013
MUCH OF PCPN NEXT 24 HOURS TIED TO ADVANCE OF UPPER COLD FRONT.
MAIN FORCING FOR PCPN LINED UP TO THE WEST OF THIS
BOUNDARY...RIGHT NOW FROM ASH TO EAU. THIS BOUNDARY IS FCST TO
SLOWLY EDGE EAST WITH TIME...THOUGH NEW MODEL RUNS SLOW IT A BIT
FURTHER THAN PREVIOUS FORECAST. HAVE BACKED OFF A BIT ON PCPN TIMING
OVER TAF SITES. CIGS TO LOWER INTO MVFR AND IFR CATEGORIES THROUGH
THIS TAF PERIOD...WITH A CLOUDY...COOL AND WET PERIOD EXPECTED THROUGH
FRIDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM TO 1 PM CDT THURSDAY FOR
WIZ005.
&&
$$
SHORT TERM.....KALLAS
LONG TERM......RDM
AVIATION.......TE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
616 AM CDT TUE APR 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM CDT TUE APR 30 2013
MAIN FORECAST CONCERNS THROUGH THIS AFTERNOON ARE ON SHOWERS AND
THUNDERSTORMS...WITH THE POTENTIAL FOR SEVERE THUNDERSTORMS ALONG A
COLD FRONT THIS AFTERNOON INTO THIS EVENING. THE FOCUS THEN QUICKLY
TURNS TO A PROLONGED PERIOD OF RAINFALL STARTING LATE TONIGHT AND
CONTINUING THROUGH FRIDAY. THERE COULD ALSO BE SIGNIFICANT SNOW
ACCUMULATIONS FROM WEDNESDAY NIGHT THROUGH THURSDAY.
SURFACE LOW PRESSURE OVER NORTHEAST SOUTH DAKOTA WILL LIFT NORTHEAST
INTO NORTHERN MINNESOTA EARLY THIS MORNING PULLING A WARM FRONT
NORTH ACROSS THE FORECAST AREA. A STRONG LOW LEVEL JET...FOCUSED INTO
NORTHEAST IOWA INTO SOUTHWEST WISCONSIN...WILL CONTINUE TO FUEL
SHOWERS AND THUNDERSTORMS EARLY IN THE MORNING...THEN THIS ACTIVITY
SHOULD QUICKLY PUSH INTO SOUTH CENTRAL WISCONSIN. AN UNSEASONABLY
WARM AIRMASS MOVES INTO THE FORECAST AREA IN THE WAKE OF THE WARM
FRONT WITH TEMPERATURES SOARING INTO THE MID 70S TO LOWER 80S. THESE
WARM TEMPERATURES WILL BE SHORT LIVED AS A COLD PUSHES INTO EASTERN
MINNESOTA/CENTRAL IOWA LATE THIS MORNING. THE FRONT WILL GRADUALLY
SLIDE SOUTHEAST ACROSS THE FORECAST AREA THIS AFTERNOON. THE MAIN
CONCERN ALONG THE FRONT TODAY IS WHEN WILL THE CONVECTION FIRE ALONG
IT. THERE IS A STRONG CAP THAT MOVES INTO THE FORECAST AREA THIS
MORNING IN THE WAKE OF THE WARM FRONT...WITH MLCIN VALUES OF 300
J/KG. THE CAP FINALLY ERODES AHEAD OF THE FRONT BY MID AFTERNOON. BY
THEN...THE FRONT LOOKS TO BE POSITIONED FROM NORTH CENTRAL WISCONSIN
STRETCHING SOUTHWEST INTO NORTHEAST IOWA. LOCATIONS ACROSS NORTHEAST
IOWA...SOUTHWEST AND CENTRAL WISCONSIN LOOK TO HAVE THE HIGHEST
CHANCES OF SEEING THUNDERSTORMS THIS AFTERNOON. THE BEST SHEAR FOR
SEVERE THUNDERSTORMS LAGS RIGHT ALONG TO JUST BEHIND THE FRONT.
SURFACE BASED CAPE VALUES CLIMB TO AROUND 1100 J/KG. IF THE STORMS
FIRE...THERE IS THE POTENTIAL FOR THEM TO BECOME SEVERE WITH LARGE
HAIL AND DAMAGING WINDS. AS THIS FRONT IS DRIFTING SOUTHEAST TODAY A
POTENT TROUGH IS DIGGING ACROSS THE NORTHWEST CONUS INTO THE
DAKOTAS. AN IMPRESSIVE FRONTOGENESIS ZONE STARTS TO TAKE SHAPE EARLY
THIS EVENING. FORECAST MODEL CROSS SECTIONS RUNNING FROM SOUTHEAST
TO NORTHWEST ACROSS THIS FRONTOGENESIS ZONE SHOW IT STRETCHING FROM
NEAR THE SURFACE OVER NORTHERN ILLINOIS THEN SLOPING BACK TO THE
NORTHWEST THROUGH CENTRAL MINNESOTA. THIS ZONE IS VERY
DEEP...EXTENDING ALL THE WAY THROUGH 500 MB. ALSO...NEGATIVE EPV IS
LOCATED JUST ABOVE THE FRONTOGENESIS. A VERY PRONOUNCED AND WIDE
BAND OF PRECIPITATION WILL DEVELOP ACROSS THE AREA TONIGHT.
LOCATIONS WEST OF HIGHWAY 63...OVER NORTHEAST IOWA AND SOUTHEAST
MINNESOTA...WILL SEE THE STEADIER RAINS MOVE IN AROUND OR SHORTLY
AFTER MIDNIGHT THEN THE BAND WILL SPREAD WEST THROUGH THE OVERNIGHT
AND IMPACTING ALL OF SOUTHEAST MINNESOTA...NORTHEAST IOWA AND MUCH
OF WESTERN WISCONSIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 429 AM CDT TUE APR 30 2013
THE TROUGH CONTINUES TO DIG SOUTHWARD ON WEDNESDAY AND THE
IMPRESSIVE FRONTOGENESIS ZONES REMAINS ANCHORED OVER THE AREA WITH
RAINFALL CONTINUING. THE HIGHEST RAINFALL AMOUNTS ARE EXPECTED TO
FALL ACROSS NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND WEST CENTRAL
INTO NORTH CENTRAL WISCONSIN. FORECAST MODELS ARE SUGGESTING
RAINFALL AMOUNTS OF 1/2 TO AROUND 3/4 INCH ARE POSSIBLE BY WEDNESDAY
AFTERNOON. THE HIGHEST AMOUNTS APPEAR FOCUSED ALONG AND WEST OF
INTERSTATE 35. RAIN WILL CONTINUE INTO WEDNESDAY NIGHT. A SWITCH
OVER TO SNOW IS EXPECTED LATE AS COLDER AIR WRAPS INTO THE SYSTEM
FROM THE NORTH AS THE TROUGH DEEPENS. THE SNOW LOOKS TO CONTINUE
INTO THURSDAY MORNING. SNOW ACCUMULATIONS OF 2 TO 4 INCHES ARE
LIKELY WEST OF A LINE FROM CHARLES CITY TO WINONA TO MEDFORD. THERE
IS THE POTENTIAL FOR A SWATH OF 5 TO 8 INCHES OF SNOW NEAR THE
INTERSTATE 35 CORRIDOR...POSSIBLY EDGING INTO
WABASHA...OLMSTED...DODGE...MOWER AND MITCHELL COUNTIES. MOST OF THE
ACCUMULATION WOULD BE ON GRASSY SURFACES WITH MAINLY A SLUSHY
ACCUMULATION ON AREA ROADS. THE BAND OF RAIN AND SNOW IS EXPECTED TO
EDGE EAST THROUGH THE DAY ON THURSDAY AND SWITCH OVER TO ALL RAIN BY
MIDDAY. IT IS IMPORTANT TO NOTE THERE REMAINS CONSIDERABLE
UNCERTAINTY ON THE EXACT PLACEMENT OF THE RAIN/SNOW LINE. IF THE LOW
TRACKS SLIGHTLY FURTHER WEST...THE FORECAST AREA COULD SEE ALL
RAIN. BY THE TIME THE PRECIP FINALLY WINDS DOWN LATE FRIDAY
RAINFALL AMOUNTS OF 2 TO 3 INCHES APPEAR LIKELY ACROSS PORTIONS OF
NORTHEAST IOWA...AND MUCH OF SOUTHEAST MINNESOTA INTO WEST CENTRAL
WISCONSIN. THESE RAINFALL AMOUNTS WOULD RESULT IN RISES ON AREA
RIVERS AND POSSIBLE FLOODING. LOCATIONS ACROSS SOUTHWEST INTO
CENTRAL WISCONSIN COULD SEE RAINFALL AMOUNTS OF 1 TO 2 INCHES...WITH
LOCALLY HIGHER AMOUNTS POSSIBLE. UNSEASONABLY COOL TEMPERATURES ARE IN
STORE FOR THE AREA AS THIS STORM SYSTEM IMPACTS THE REGION...WITH
HIGHS ON THURSDAY RANGING FROM THE MID MID 30S ACROSS SOUTHEAST
MINNESOTA TO THE UPPER 40S OVER CENTRAL WISCONSIN. THE TROUGH CLOSES
INTO A CUTOFF LOW FRIDAY INTO SATURDAY. FORECAST MODELS ARE SHOWING
DIFFERING SOLUTIONS WITH THE TRACK OF THE CUTOFF LOW. THE ECMWF
PLACES THE CENTER OF THE LOW OVER WESTERN IOWA/EASTERN NEBRASKA ON
FRIDAY...THEN LIFTS IT NORTH INTO NORTHERN MINNESOTA SATURDAY INTO
SUNDAY. THE GFS TAKES THE LOW WAY TO THE SOUTH AND CUTS IT OFF OVER
NORTHERN ARKANSAS. THE GEM OFFERS A SOLUTION IN BETWEEN THE ECMWF
AND GFS...CUTTING THE LOW OFF OVER NORTHERN MISSOURI AND LIFTING IT
NORTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY LATE SATURDAY
THROUGH SUNDAY. WILL LEAN TOWARD A MODEL CONSENSUS BLEND SATURDAY
INTO MONDAY...KEEPING CHANCES FOR RAIN ACROSS THE FORECAST AREA.
TEMPERATURES WILL GRADUALLY RECOVER THIS WEEKEND WITH HIGHS ON
SUNDAY EDGING INTO THE MID TO UPPER 50S.
&&
.AVIATION...TODAY AND TONIGHT
616 AM CDT TUE APR 30 2013
A WARM FRONT HAS LIFTED NORTH THROUGH BOTH TAF SITES WITH THE
WINDS COMING AROUND TO THE SOUTH. SECONDARY BAND OF THUNDERSTORMS
FORMED ALONG THE FRONT BUT HAVE ALREADY MOVED PAST KLSE AND DO NOT
PLAN TO INCLUDE THESE IN THE 12Z TAF. EVEN THOUGH THE WARM FRONT
HAS MOVE THROUGH...VWP WINDS FROM THE KARX RADAR STILL SHOWS LOW
LEVEL WIND SHEAR IS OCCURRING WITH 45 KNOTS AT 2000 FEET. BOTH THE
30.06Z NAM AND 30.09Z RAP SHOW THIS CONTINUING THROUGH MID MORNING
BEFORE THE LOW LEVEL JET STARTS TO DISSIPATE ALLOWING THE WINDS
ALOFT TO DIMINISH. AS THE COLD FRONT APPROACHES FROM THE
WEST...GOOD MIXING AHEAD OF IT SHOULD PRODUCE GUSTY SOUTHWEST
WINDS AT BOTH SITES. THE COLD FRONT SHOULD PASS THROUGH KRST EARLY
THIS AFTERNOON SWITCHING THE WINDS AROUND TO THE WEST/NORTHWEST
AND THEN GOING THROUGH KLSE AROUND 00Z OR SO. SCATTERED SHOWERS
AND STORMS SHOULD OCCUR ALONG THE FRONT BUT EXPECTING THE COVERAGE
TO BE TOO LIMITED TO EVEN INCLUDE A VCTS AT THIS TIME FOR EITHER
SITE. THE FRONTOGENESIS GETS GOING IN THE 850-700 MB LAYER THIS
EVENING BEHIND THE FRONT WHICH SHOULD ALLOW SOME LIGHT RAIN TO
FORM AND SPREAD OVER BOTH TAF SITES DURING THE EVENING. THIS
FRONTOGENESIS THEN LOOKS TO TEMPORARILY WEAKEN OVERNIGHT ALLOWING
THE LIGHT RAIN TO END FOR A WHILE. IN GENERAL...VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.
&&
.HYDROLOGY...
ISSUED AT 429 AM CDT TUE APR 30 2013
HEAVY PRECIPITATION RATES ARE EXPECTED WEDNESDAY INTO FRIDAY AS A
STORM SYSTEM STALLS ACROSS THE REGION. IF THE PRECIPITATION FALLS
MAINLY AS RAIN...THERE IS THE POTENTIAL FOR 2 TO 3 INCHES TO FALL BY
FRIDAY...PARTICULARLY IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THIS ADDITIONAL RAINFALL WILL LEAD TO RISES AND POSSIBLE FLOODING ON
LOCAL RIVERS AND STREAMS WHICH ARE ALREADY SOME WHAT HIGH DUE TO
RECENT PRECIPITATION AND THE SPRING SNOW MELT. LOCATIONS ACROSS
WESTERN INTO CENTRAL WISCONSIN COULD SEE 1 TO 2 INCHES OF RAINFALL
OUT OF THIS SYSTEM. THERE REMAINS UNCERTAINTY ON PLACEMENT OF THE
HEAVIEST BAND OF RAINFALL. AT THIS TIME IT APPEARS THAT PORTIONS OF
WEST CENTRAL WISCONSIN...SOUTHEAST MINNESOTA...AND NORTHEAST IOWA
WILL SEE THE HIGHEST RAINFALL AMOUNTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 PM CDT MON APR 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM CDT MON APR 29 2013
THE MAIN FOCUS TONIGHT INTO TOMORROW IS ON THE CHANCES FOR
THUNDERSTORMS TO GO ALONG WITH HOW WARM IT WILL GET BEFORE A COLD
FRONT SWINGS THROUGH TOMORROW.
CURRENTLY...A SURFACE COLD FRONT HAS STALLED OUT ACROSS THE REGION
FROM NORTH CENTRAL WISCONSIN DOWN INTO EASTERN NEBRASKA WITH A
SURFACE LOW TRACKS ALONG THE US/CANADIAN BORDER IN SOUTHERN
SASKATCHEWAN. AS THIS LOW TRACKS EAST TONIGHT...THE FRONT WILL
TRANSITION TO A WARM FRONT AND LIFT NORTH TOWARD LAKE SUPERIOR BY
TOMORROW MORNING. LOW LEVEL MOISTURE TRANSPORT WILL NOSE UP ALONG
THE FRONT AND COULD LEAD TO SOME CONVECTIVE DEVELOPMENT ALONG THIS
BOUNDARY AS A RESULT. MODIFIED 29.18Z RAP SOUNDINGS WITH SURFACE
DEW POINTS IN THE MID 50S SHOW ABOUT 1000-1500 J/KG OF 0-3KM
MUCAPE POOLING ALONG THIS FRONT AS IT LIFTS NORTH OVERNIGHT. MUCH
OF THE DEEP LAYER SHEAR APPEARS TO BE IN THE LOW LEVELS UNDER THE
INVERSION AND NOT IN THE ELEVATED PORTIONS OF THE PROFILE. WITH
FREEZING LEVELS FAIRLY LOW ALONG THE NORTHERN PERIPHERY OF THE
FRONT...EXPECT THAT SOME STRONG TO ISOLATED SEVERE STORMS WILL BE
POSSIBLE OVERNIGHT. LARGE HAIL WILL LIKELY BE THE MAIN THREAT DUE
TO THE HIGH INSTABILITY AND STABLE BOUNDARY LAYER TO PREVENT THE
STRONGEST GUSTS FROM MAKING IT TO THE SURFACE.
STRONG SOUTHERLY WINDS AHEAD OF THE MAIN COLD FRONT THAT WILL BE
INTO MINNESOTA BY TOMORROW MORNING WILL HELP TO BRING TEMPERATURES
UP TOWARD 80 FOR MUCH OF THE REGION. THE 29.12Z NAM/GFS/ECMWF HAVE
MERGED ON A SOLUTION WITH THE TIMING OF THE FRONTAL PASSAGE WITH
IT GENERALLY EXTENDING FROM NORTH CENTRAL WISCONSIN TOWARD CENTRAL
IOWA BY 18Z TOMORROW AND NEAR THE IOWA/MINNESOTA/WISCONSIN TRIPLE
POINT BY 00Z WEDNESDAY. THIS TIMING OF THE FRONT COMING THROUGH
DURING THE DIURNAL PEAK HEATING IN THE AFTERNOON LEADS TO SOME
HIGHER CONFIDENCE IN THINKING THAT THE CONVECTION WILL DEVELOP
MAINLY ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA IN THE LATE
AFTERNOON AND EARLY EVENING HOURS. ONE CONCERN IS THE 850MB CAP
THAT APPEARS TO HOLD ON THROUGH AT LEAST THE EARLY AFTERNOON
HOURS. MODEL SURFACE DEW POINTS APPEAR TO AGAIN PLAY A FACTOR IN
GENERATING TOO MUCH INSTABILITY AND BREAKING THE CAP BY MID
AFTERNOON. THE 29.12Z NAM COMES IN WITH SURFACE DEW POINTS IN THE
LOW 60S WHILE MIXED LAYER DEW POINTS COME IN AROUND THE MID TO
UPPER 50S AND APPEAR MORE REASONABLE. THIS KNOCKS SURFACE BASED
CAPE DOWN FROM AROUND 1000-2000 J/KG WITH NO CIN DOWN TO HAVING
ABOUT 500 J/KG OF SBCAPE AND OVER 100 J/KG OF CIN WITH THE LOWER
DEW POINTS. THE FORCING ALONG THE FRONT SHOULD BE ENOUGH TO
DEVELOP SOME STORMS...BUT THE COVERAGE WILL BE DEPENDENT UPON HOW
MUCH OF THE CAP CAN BE ERODED AHEAD OF THE FRONT. DEEP SHEAR IS A
LITTLE BETTER ACROSS CENTRAL WISCONSIN AND IS MAINLY UNIDIRECTIONAL
SO STORM MODE SHOULD MAINLY BE MULTICELL CLUSTERS OR SOME BOWING
SEGMENTS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CDT MON APR 29 2013
TUESDAY NIGHT THROUGH THURSDAY
THIS FRONT WILL STALL OUT ACROSS SOUTHERN WISCONSIN AND EASTERN
IOWA INTO TUESDAY NIGHT WITH IT EVENTUALLY WEAKENING TOWARD
WEDNESDAY MORNING. AS THIS OCCURS...THE MAIN MID LEVEL TROUGH WILL
START CARVING OUT ACROSS THE CENTRAL PLAINS WITH A STRONG BAND OF
FRONTOGENESIS ALIGNING FROM NORTH TO SOUTH ACROSS THE UPPER
MISSISSIPPI VALLEY REGION. THIS WILL LEAD TO A PROLONGED PERIOD OF
MODERATE TO HEAVY PRECIPITATION...PARTICULARLY ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA WEDNESDAY INTO THURSDAY. PRECIPITATION
WILL START OUT AS ALL RAIN ON WEDNESDAY...BUT THEN IS EXPECTED TO
COOL ENOUGH TO CHANGE OVER TO ALL SNOW IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA LATE WEDNESDAY NIGHT INTO THURSDAY. THE 29.12Z
NAM/GFS AND 29.15Z SREF ALL BACK THIS IDEA...THOUGH THE 29.12Z
ECMWF HAS COME BACK IN AS A WARM OUTLIER AND BRINGS THE MOST
UNCERTAINTY TO THIS FORECAST. THE WARM LAYER THAT THIS RUN OF THE
ECMWF PRODUCES TAKES THE MAIN SNOW BAND FURTHER TO THE WEST AND
OUT OF THE FORECAST AREA. THE CONSENSUS...OUTSIDE OF THE
ECMWF...WAS TO KEEP THE PRECIPITATION TYPE AS MAINLY SNOW ACROSS
SOUTHEAST MINNESOTA AND PORTIONS OF NORTH CENTRAL/EAST IOWA LATE
WEDNESDAY NIGHT INTO THURSDAY. SNOWFALL AMOUNTS ARE CURRENTLY
FORECAST TO MAINLY BE IN THE 2 TO 4 INCH RANGE...WITH A FEW SPOTS
THAT END UP UNDER THE MAIN BAND POTENTIALLY HITTING 6 INCHES OR
HIGHER. BECAUSE OF THE ECMWF...CONFIDENCE IS NOT HIGH ENOUGH YET
TO PUT OUT A WINTER STORM WATCH...BUT LATER SHIFTS WILL HAVE TO
WATCH FOR TRENDS ON THIS BAND AND WHERE IT ENDS UP.
THURSDAY NIGHT THROUGH MONDAY
THIS PERIOD IS CHARACTERIZED BY LOW CONFIDENCE AS THE LARGE CLOSED
LOW OVER THE CENTRAL U.S. IS STILL PRODUCING GREAT SPREAD WITHIN THE
NUMERICAL GUIDANCE. THESE ARE TRADITIONALLY HIGH SPREAD SITUATIONS
FOR THE MODELS. THUS...USED THE CONSENSUS BLEND AS IS FOR THE
PERIOD.
THE BIG PICTURE FOR THIS THE PERIOD BEGINS WITH THE STRONG
FRONTOGENESIS OVER THE FORECAST AREA WEAKENING WITH TIME AND WARMING
BEGINNING. THIS WARMING IS GENERALLY AGREED ON...WHICH WOULD CHANGE
ANY SNOW TO RAIN BY SATURDAY. THE LATEST 28.12Z ECMWF SUGGESTS A
WARMER SOLUTION TO THE ENTIRE PERIOD WITH ALL RAIN...EVEN IN WESTERN
MOST PART OF THE FORECAST AREA.
AS THE UPPER LOW SHIFTS EAST/NORTHEAST...A SURFACE LOW DEEPENS AND
ROTATES NORTH-NORTHWEST AND ELICITS HEAVY RAINFALL AHEAD OF IT ON
THE EAST SIDE OF THE UPPER LOW IN A RICH...OPEN GULF OF MEXICO FLOW.
THUS...SOME AREAS WILL SEE 1-2 INCHES OF RAIN INTO THE EARLY
WEEKEND...BUT THE BIG PROBLEM IS...WHERE. THE MODEL SPREAD WITH THIS
RAINFALL IS FROM KANSAS CITY MO /28.12Z GEM AND GFS/ TO THE LOCAL
AREA /28.12Z ECMWF/. IF THE EARLY PORTION OF THE FRONTOGENESIS
PRECIPITATION ON WED-THU IS ALL RAIN...THERE COULD BE 4 INCHES OF
RAINFALL THIS WEEK BY SUNDAY. THE HIGHEST CONFIDENCE OF THIS
OCCURRING LOOKS TO BE NEAR I-35 JUST EAST OF ANY SNOW BAND THAT
FORMS. THIS WOULD PROBABLY INCLUDE PARTS OF THE WESTERN FORECAST
AREA. BUT...THIS AGAIN IS LOW CONFIDENCE. IT SEEMS THE PATTERN SAYS
IT WILL HAPPEN BUT THE LOCATION IS A TOUGH CALL RIGHT NOW.
FOR THE SUNDAY AND MONDAY PERIOD...THE LOW SHOULD HAVE LESS AND LESS
IMPACT WITH WARMING TEMPERATURES AND MORE SCATTERED SHOWERY WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1145 PM CDT MON APR 29 2013
SUMMARY...VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING WITH
BREEZY SOUTH TO SOUTHWEST WINDS DROPPING DOWN TO THE SURFACE
DURING THE MORNING.
DETAILS...
SHOWERS AND THUNDERSTORMS HAVE FORMED OVER CENTRAL IOWA ALONG A
WARM FRONT AS EXPECTED. MODEL GUIDANCE AS WELL AS EXTRAPOLATION
WOULD SUGGEST THESE STAY SOUTHEAST OF THE TAF SITES FOR THE
MORNING HOURS...THOUGH KLSE COULD GET BRUSHED. AS A RESULT...HAVE
MAINTAINED THAT VCSH FOR 09-14Z. ADDITIONALLY...A 40-50 KT JET
BETWEEN 1500-2000 FT AGL IS PRESENT AS SEEN ON RADAR VAD WIND
PROFILE DATA OVER THE TAF SITES. WITH SOUTHEAST WINDS AT THE
SURFACE BEING NORTH OF THE WARM FRONT...LOW LEVEL WIND SHEAR IS
OCCURRING. THIS LOW LEVEL WIND SHEAR LOOKS TO PERSIST UNTIL A FEW
HOURS AFTER SUNRISE WHEN MIXING CAN TRANSPORT SOME OF THIS WIND TO
THE SURFACE AS GUSTS. THESE GUSTS SHOULD REACH 20-30 KT. DURING
THE AFTERNOON...A COLD FRONT IS PROGGED TO MOVE THROUGH THE TAF
SITES...AROUND 19Z AT KRST AND 23-00Z AT KLSE. THIS FRONT WILL
HELP DIMINISH THE GUSTS AND EVENTUALLY SWING WINDS AROUND TO THE
NORTHWEST. UNCERTAINTY REMAINS IF ANY STORMS CAN FIRE ON THIS
FRONT. IF THEY DO...KLSE WOULD BE THE SITE MORE LIKELY TO BE
IMPACTED. BETTER CHANCE FOR RAIN...FOR BOTH TAF SITES...LOOKS TO
OCCUR AFTER THE FRONT PASSES...BEGINNING AROUND 02Z. CEILINGS AND
VISIBILITIES APPEAR TO STAY VFR... THOUGH. THERE COULD BE SOME
THUNDER ACCOMPANYING THE SHOWERS...BUT THE COVERAGE RIGHT NOW
SEEMS ISOLATED AT BEST AND THUS CONFIDENCE IS TOO LOW TO MENTION.
&&
.HYDROLOGY...
ISSUED AT 324 PM CDT MON APR 29 2013
HEAVY PRECIPITATION RATES ARE EXPECTED WEDNESDAY INTO FRIDAY AS A
STORM SYSTEM STALLS ACROSS THE REGION. IF THE PRECIPITATION FALLS
MAINLY AS RAIN...THERE IS THE POTENTIAL FOR 1 TO 3 INCHES TO FALL
BY FRIDAY...PARTICULARLY IN SOUTHEAST MINNESOTA AND NORTHEAST
IOWA. THIS ADDITIONAL RAINFALL WILL LEAD TO SOME RISES ON LOCAL
RIVERS AND STREAMS WHICH ARE ALREADY SOME WHAT HIGH DUE TO RECENT
PRECIPITATION AND THE SPRING SNOW MELT. CONFIDENCE IS NOT VERY
HIGH AT THIS POINT WITH WHERE THIS MAIN BAND WILL SET UP OR IF IT
WILL END UP AS SNOW...BUT THE GENERAL AREA THAT APPEARS TO TAKE
THE BRUNT OF THIS SYSTEM IS SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH/BAUMGARDT
AVIATION...AJ
HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1112 PM CDT MON APR 29 2013
.UPDATE...
CONVECTION HAS DISSIPATED AS IT RAN OUT OF SFC BASED CAPE. HOWEVER
ELEVATED CAPE OF 500-1000 J/KG AND LOW TO MID LEVEL WARM...MOIST
ADVECTION REMAINS OVER MUCH OF SRN WI AS A 50 KT SLY LLJ IS
ONGOING OVER THE AREA. THEREFORE...ELEVATED CONVECTION WILL REMAIN
A POSSIBILITY LATE THIS EVENING INTO THE OVERNIGHT. MORE
WIDESPREAD SHOWERS AND TSTORMS ARE EXPECTED AFTER 09Z FOR THE WRN
AND NRN CWA AS CONVECTION OVER CENTRAL IA ORGANIZES INTO A MCS.
THIS CONVECTION IS ASSOCIATED WITH WARM...MOIST ADVECTION ON A
SEPARATE 60 KT LLJ THAT WILL MOVE FROM KS TO IA TO CNTRL/SRN WI
FOR TUE AM. CONVECTION TO END BY MID MORNING WITH A VERY
WARM...WINDY AND CAPPED WARM SECTOR EXPECTED FOR MUCH OF THE DAY.
HIGH TEMPS INTO THE MID 80S ARE POSSIBLE. A COLD FRONT WILL THEN
STALL NW OF MADISON WITH SHOWERS AND TSTORMS EXPECTED THERE LATE
TUE AFTERNOON AND NIGHT.
&&
.AVIATION/06Z TAFS/...ONLY VERY SMALL CHANCES OF SHOWERS OR
TSTORMS LATE THIS EVENING INTO THE EARLY MORNING HOURS. SHOWERS
AND TSTORMS WILL THEN ARRIVE OVER KMSN AROUND 09Z-10Z AND LAST 2-4 HOURS.
MORE UNCERTAINTY FOR THE SE WI TAF SITES AS THE MAIN AREA OF
TSTORMS MAY MISS THEM TO THE NORTH. THREAT OF TSTORMS TO THEN END
BY MID MORNING WITH A CAPPED ATMOSPHERE INTO TUE EVENING FOR THE
SE WI TAF SITES. KMSN WILL HAVE CHANCES OF TSTORMS TUE NIGHT BUT
WITH MUCH BETTER CHANCES TO THEIR NW WHERE THE COLD FRONT STALLS.
VFR CONDITIONS TO PREVAIL EXCEPT IN TSTORMS.
&&
.PREV DISCUSSION... /ISSUED 420 PM CDT MON APR 29 2013/
VERY SHORT TERM...TONIGHT AND TUESDAY. FORECAST CONFIDENCE IS
MEDIUM.
LINE OF ELEVATED SHOWERS AND A FEW THUNDERSTORMS SHIFTING EAST
NORTHEAST THROUGH THE AREA AT THIS TIME...BEING FED BY SOUTH
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE. THESE SHOULD CONTINUE TO
MOVE THROUGH THE REMAINDER OF THE AREA LATE THIS AFTERNOON.
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE WILL CONTINUE TO POINT INTO
THE AREA TONIGHT...GRADUALLY INCREASING IN MAGNITUDE. WARM AIR
ADVECTION KICKS IN TONIGHT AS WELL. TAIL END OF 500MB VORTICITY
MAXIMUM OVER SOUTHERN MINNESOTA WILL SHIFT CLIP THE NORTHERN
PORTIONS OF THE AREA THROUGH EARLY EVENING...WITH ANOTHER OVER
EASTERN NEBRASKA SHIFTING INTO THE AREA BY 06Z TUESDAY.
ADJUSTING AREA FORECAST SOUNDINGS FOR LOWER TO MID 50S DEW POINTS
YIELD MEAN LAYER CAPES OF UP TO 500 J/KG INTO EARLY EVENING...THEN
SHOW ELEVATED CAPES INCREASING TONIGHT OVER 1000 J/KG. THIS IS IN
RESPONSE TO MOISTURE BUILDING IN THE 925MB TO 850MB LEVEL. DEEP
LAYER SHEAR IS STRONG INTO EARLY EVENING...THEN WEAKENS SOMEWHAT
LATER TONIGHT AS MID LEVEL WINDS WEAKEN. SPC HAS SLIGHT RISK AREA
INTO JUST THE FAR SOUTHWESTERN SECTIONS OF THE AREA. MAIN RISK
APPEARS TO BE IN IOWA...THOUGH IF HIGHER DEW POINTS MOVE IN AND
INCREASE CAPE THIS EVENING...COULD SEE A SEVERE STORM OR TWO OCCUR.
4KM WRF/NMM MODEL SHOWING SPOTTY SHOWERS AND A FEW STORMS THIS
EVENING...WITH A MORE ORGANIZED AREA OF SHOWERS AND STORMS FOR LATER
TONIGHT WITH LOW LEVEL JET FORCING. HRRR KEEPING BULK OF CONVECTION
JUST SOUTH AND SOUTHWEST OF THE AREA TONIGHT. FOR NOW...WILL GO WITH
SCATTERED SHOWERS AND ISOLATED STORMS EARLY THIS EVENING...WITH
THUNDER FOR LATER THIS EVENING AND OVERNIGHT.
MODELS SHOWING WARM SECTOR AIRMASS MOVING INTO THE AREA
TUESDAY...CAPPING OFF THE AREA FROM PRECIPITATION. GUSTY
SOUTH/SOUTHWEST WINDS AND EXPECTED 925MB TEMPERATURES SHOULD BRING
HIGHS INTO THE LOWER 80S IN MOST AREAS. COOLER VALUES NEAR SHEBOYGAN
WITH SOUTH ONSHORE WINDS. APPROACHING COLD FRONT LATER IN THE
AFTERNOON SHOULD BRING INCREASED CHANCES FOR THUNDERSTORMS...THOUGH
BEST SHOT IS INTO TUESDAY NIGHT.
SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE LOW TO MEDIUM.
THUNDERSTORMS ALONG AND AHEAD OF THE FRONTAL BOUNDARY ONGOING AT THE
BEGINNING OF THE PERIOD EXPECTED TO TRANSITION TO MAINLY RAIN
SHOWERS FROM NORTHWEST TO SOUTHEAST BEHIND THE FRONT ON WEDNESDAY AS
IT SAGS THROUGH THE FORECAST AREA. THOUGH SURFACE FRONT MAKES IT TO
OR NEAR SE WI BY 12Z WED...UPPER TROUGH STILL WELL TO THE WEST AND
WILL KEEP THE FOCUS FOR PRECIPITATION THROUGH IOWA INTO WESTERN WI.
WILL KEEP CHANCE POPS ALONG THE FRONT.
LOWS WILL NOT FALL OFF MUCH TUESDAY NIGHT UNTIL LATE IN THE
NW...THEN WARM SE WEDNESDAY AHEAD OF STALLED BAROCLINIC ZONE
BISECTING THE CWA...THOUGH COOLER ALONG THE LAKE.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM.
LIKELY POPS INTO THE WESTERN CWA WITH INCREASING FORCING AHEAD OF
SLOWLY APPROACHING TROUGH AS IT DEEPENS OVER THE CENTRAL U.S.
MODELS STILL DIFFER WITH THE PLACEMENT OF BAROCLINIC ZONE WHICH
AFFECTS NOT ONLY TEMPERATURES BUT LOCATION OF BETTER LOW TO MID
LEVEL FRONTOGENESIS AND Q-VECTOR CONVERGENCE.
BLENDED SOLUTION KEEPS LIKELY POPS OVER SOUTH CENTRAL WI THROUGH THE
DAY THURSDAY...THEN SHIFT ACROSS THE ENTIRE CWA THURSDAY NIGHT.
THERMAL RIDGE NOSING INTO THE FAR SOUTH WILL BRING HIGHS IN THE
UPPER 50S THERE...THEN TAPER OFF TO THE MID 40S NW WITH UPPER 40S
ALONG THE LAKE.
LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE...
LOW.
MODELS STILL TRYING TO GET A HANDLE ON LOW CUTTING-OFF OVER THE
CENTRAL PLAINS THURSDAY NIGHT AND THEN LIFTING SLOWLY NWD INTO THE
UPPER MIDWEST SUNDAY. SOME THERMAL DIFFERENCES THAT MAY IMPACT
PRECIPITATION TYPE AND BRING SOME SNOWFLAKES MIXING IN WITH THE RAIN
IN THE FAR WEST/NW LATE THURSDAY NIGHT...BUT WILL LEAVE ALL LIQUID
FOR NOW. OTHERWISE A CLOUDY...COOL AND WET PERIOD THROUGH THE
WEEKEND WITH TEMPERATURES STRUGGLING INTO THE LOWER 50S...COOLER BY
THE LAKE WITH GENERALLY EASTERLY FLOW. PERIODS OF RAIN...WITH
INTENSITY DEPENDENT ON STRENGTH OF VORTICITY MAXIMA ROTATING THROUGH
THE REGION AND THE AMOUNT OF AVAILABLE MOISTURE WITH STREAMERS OF
DRIER AIR WRAPPING AROUND CIRCULATION. SOME HOPE THAT THE LOW WILL
LIFT FAR ENOUGH AWAY BY MONDAY TO LOWER RAIN CHANCES AND ALLOW
WARMER TEMPS.
AVIATION/00Z TAFS/...
VFR CONDITIONS ARE EXPECTED THIS EVENING ACROSS TAF SITES. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS MOVING THROUGH AT THIS TIME...WITH
MORE AT TIMES MAINLY LATER TONIGHT INTO EARLY TUESDAY MORNING. THERE
WILL BE LULLS IN THE PRECIPITATION.
FOR NOW...WILL KEEP VICINITY THUNDER WORDING IN TAFS...AS THERE IS
SOME UNCERTAINTY WITH THE EXACT TIMING AND AREAL COVERAGE OF THE
SHOWERS AND STORMS. ANY STORMS WOULD BRING VISIBILITIES DOWN TO
NEAR ALTERNATE MINIMUMS...WITH MVFR CEILINGS.
SOUTH WINDS TONIGHT WILL GRADUALLY INCREASE AND SHIFT SOUTHWEST BY
TUESDAY AFTERNOON. GUSTS TO 25 KNOTS OR SO ARE EXPECTED BY TUESDAY
AFTERNOON.
MARINE...
A TIGHT PRESSURE GRADIENT WILL DEVELOP OVER THE NEARSHORE WATERS
TUESDAY...WHICH WILL RESULT IN GUSTY SOUTH WINDS. FREQUENT GUSTS TO
25 KNOTS ARE EXPECTED. THUS...A SMALL CRAFT ADVISORY WILL BE ISSUED
FROM MID MORNING THROUGH EARLY EVENING TUESDAY.
ANOTHER TIGHT PRESSURE GRADIENT WILL DEVELOP WITH THE INFLUX OF
COLDER AIR FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THIS WILL
BRING BRISK AND GUSTY NORTH TO NORTHEAST WINDS DURING THIS
TIME...ALONG WITH HIGH WAVES. A SMALL CRAFT ADVISORY MAY BE NEEDED
DURING THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR
LMZ643>646.
&&
$$
UPDATE...GEHRING
TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS MIAMI FL
159 AM EDT THU MAY 2 2013
.AVIATION...
A TROUGH OF LOW PRESSURE ACROSS THE REGION WILL CONTINUE TO BRING
SHOWER AND/OR THUNDERSTORMS MAINLY FROM LATE THIS MORNING AND INTO THE
EVENING HOURS OF THURSDAY. THERE IS A CHANCE OF AN EARLIER START
BASED ON CURRENT TRENDS WITH ACTIVITY ACROSS THE KEYS POTENTIALLY
PROPAGATING NORTH INTO THE REGION TOWARDS SUNRISE SO WILL BE
MONITORING THAT. THIS MEANS THAT ALTHOUGH VFR TO MVFR (FOR CEILINGS)
CONDITIONS ARE EXPECTED TO PREVAIL OVER THE NEXT 24 HOURS OR SO
AT THE TAF SITES, PERIODS WITH MIXED MVFR AND MAY BE EVEN IFR ARE
POSSIBLE WITH ANY STORMS AFFECTING THE TERMINALS, AND IN PARTICULAR
THE EAST COAST TERMINALS FROM AROUND NOON AND INTO THE EVENING
HOURS WITH THE CAVEAT MENTIONED EARLIER. ALSO PERIODS OF MVFR OR
EVEN IFR CEILINGS CANNOT BE RULED OUT EARLY THIS MORNING WITH LOW
STRATUS CLOUDS AT ANY OF THE TERMINALS. BUT GIVEN UNCERTAINTY WILL
HANDLE THOSE WITH AMENDMENTS AS NEEDED.
WINDS WILL REMAIN LIGHT FROM THE EAST OR VARIABLE THIS MORNING
BECOMING SE 8-13 KTS TODAY WITH A SSW SEA BREEZE DURING THE
AFTERNOON POSSIBLE AT APF. WINDS WILL BECOME LIGHT GENERALLY FROM
THE SE ONCE AGAIN TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 827 PM EDT WED MAY 1 2013/
UPDATE...
CHANCES FOR SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL PREVAIL
THROUGH THE NIGHT AS WEAKNESSES IN THE MID LEVEL FLOW CONTINUE TO
PUSH ACROSS THE AREA. LATEST IR SATELLITE IMAGERY SHOWS AN MCS
SITUATED ACROSS THE SOUTH CENTRAL GULF OF MEXICO MOVING SOUTH
TOWARD THE YUCATAN CHANNEL. LATEST SHORT TERM MODELS INCLUDING
LOCAL MODEL DATA DEPICTS A FEW ASSOCIATED SHOWERS AND
THUNDERSTORMS PUSHING EAST AND INTO THE EASTERN GULF WATERS BY
EARLY TOMORROW MORNING. KEPT CHANCE POP ACROSS THE ENTIRE AREA
THROUGH THE MORNING HOURS. UPDATE WILL BE SENT SHORTLY.
PREV DISCUSSION... /ISSUED 744 PM EDT WED MAY 1 2013/
AVIATION...
A TROUGH OF LOW PRESSURE THAT BROUGHT SHOWERS AND THUNDERSTORMS
TODAY, WILL CONTINUE TO BRING SOME SHOWER ACTIVITY INTO THE LATE
EVENING HOURS. THIS MEAN VFR TO MVFR CONDITIONS ARE EXPECTED
OVERNIGHT, WITH VFR IN THE MORNING, RETURNING TO A MIX OF VFR AND
MVFR TOMORROW. THIS IS DUE TO ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS EXPECTED TO DEVELOP AROUND MID DAY. WINDS WILL BE
LIGHT AND VARIABLE FOR A WHILE THIS EVENING, BEFORE BECOMING
EASTERLY BETWEEN 5 AND 10 KTS. THEY WILL INCREASE TO 10 TO 15 KTS
TOMORROW MORNING.
PREV DISCUSSION... /ISSUED 238 PM EDT WED MAY 1 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
LARGE CUT-OFF MID LEVEL LOW CONTINUES TO SLOWLY DRIFT EAST ACROSS
THE SOUTH CENTRAL GULF STATES. A LARGE CLUSTER OF CONVECTION
DEVELOPED ON THE SOUTHERN FRINGES OF THIS LOW AND HAS MOVED EAST
THROUGH EARLY THIS AFTERNOON AND AS OF 1830Z WAS MOVING ACROSS THE
INTERIOR AND TOWARDS THE EAST COAST METRO AREA. ANOTHER CLUSTER OF
CONVECTION IS ALSO CURRENTLY DEVELOPING OVER THE CENTRAL GULF WITH
THE HRRR SHOWING THIS MOVING ACROSS SOUTH FLORIDA THIS EVENING SO
HAVE INCREASED THE POPS FOR THE OVERNIGHT HOURS. AT THE SAME TIME, A
DEEPENING TROUGH INTO THE CENTRAL PLAINS STATES ON THURSDAY WILL
CONTINUE TO DEEPEN AND CUT OFF OVER THE MISSISSIPPI VALLEY WITH
THE SOUTHERN CUT-OFF LOW BECOMING PHASED IN WITH THIS LOW. THIS
KEEPS SOUTH FLORIDA IN RICH TROPICAL FLOW OF AIR THROUGH THE END
OF THE WEEK WITH HIGH CHANCES FOR SHOWERS AND THUNDERSTORMS.
FORECAST SOUNDINGS THROUGH THIS PERIOD LOOK QUITE SIMILAR WITH
PWAT REMAINING WELL ABOVE NORMAL FOR EARLY MAY AND A WEAK WESTERLY
STEERING FLOW. GLOBAL MODELS ARE NOW MORE IN AGREEMENT WITH THE
OVERALL SOLUTION DURING THE NEXT 48 HOURS AND SHOW THE LOW
DRIFTING TO THE SOUTHEAST BEFORE GETTING PHASED IN WITH THE
UPSTREAM DEEPENING TROUGH. THIS ON THURSDAY AND POSSIBLY FRIDAY
WILL DESTABILIZE THE ATMOSPHERE WITH COOLING 500 MB TEMPERATURES.
THE 12Z MFL SOUNDING SHOWED A TEMPERATURE OF -10 CELSIUS AND THE
GFS SHOWS COOLING TO AROUND -12 ON THURSDAY INTO FRIDAY. SO THE
CONTINUED THREAT FOR STRONG STORMS WILL ALSO BE A FACTOR. OF
COURSE THERE WILL ALWAYS BE SOME DAY TO DAY FLUCTUATIONS WITH WEAK
DISTURBANCES MOVING THROUGH THE BASE OF THE TROUGH.
LONG TERM (SATURDAY THROUGH WEDNESDAY)...
THE EXTENDED PORTION OF THE FORECAST CONTINUES TO BE HIGHLY
UNCERTAIN WITH THE GFS AND ECMWF HAVING TWO DIFFERENT SOLUTIONS TO
THE DEEPENING TROUGH. BOTH CUT THIS LOW OFF FROM THE NORTHERN
LATITUDE FLOW AS MENTIONED ABOVE. THE GFS THEN DEVELOPS A MASSIVE
CUT-OFF LOW AND THEN SLOWLY DRIFTS IT TO THE EAST THROUGH THE MIDDLE
OF NEXT WEEK. THIS WOULD TEND TO DRAW A DRIER AIR MASS ACROSS SOUTH
FLORIDA FOR LESSER STORM ACTIVITY. HOWEVER, THE ECMWF SPLITS THE
CUT-OFF LOW DRIFTING THE SOUTHERN PORTION TO THE SOUTH WHICH WOULD
KEEP SOUTH FLORIDA VERY UNSTABLE. FOR NOW, WILL GO WITH THE GFS
SOLUTION AS THIS MODEL HAS BEEN THE MOST CONSISTENT IN ITS FORECAST
WHERE THE ECMWF HAS HAD DIFFERENT SOLUTIONS WITH EACH RUN.
MARINE...
TRANQUIL CONDITIONS OUTSIDE OF ISOLATED STRONG CONVECTION WILL
CONTINUE THROUGH THURSDAY. SOME INCREASE IN A NORTHEAST SWELL IS
EXPECTED LATE IN THE WEEK INTO THE WEEKEND WITH POSSIBLE SEAS
BUILDING TO 7 FEET OVER THE PALM BEACH WATERS.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH DEEP TROPICAL MOISTURE REMAINING IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 70 81 71 / 70 50 60 50
FORT LAUDERDALE 81 71 82 73 / 70 50 60 50
MIAMI 81 71 83 73 / 70 50 60 40
NAPLES 85 67 83 67 / 50 40 50 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...52/PS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
458 AM EDT THU MAY 2 2013
.SYNOPSIS...
HIGH PRESSURE WILL GRADUALLY WEAKEN AND RETREAT INTO THE ATLANTIC
THROUGH THE WEEKEND...AND DEEP LOW PRESSURE WILL SLOWLY ROLL FROM
THE GREAT PLAINS ACROSS THE SOUTHEAST THROUGH THE MIDDLE OF NEXT
WEEK. THIS LOW PRESSURE WILL PUSH A COLD FRONT THROUGH THE AREA LATE
THIS WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-DAWN...DEEP LAYERED MOISTURE ADVECTION HAS NUDGED A BIT FURTHER
N THIS MORNING WITH PWATS OBSERVED BY THE LATEST RAP MODEL OUTPUT RIGHT
BETWEEN THE GFS AND NAM AT 06Z- 08Z. THE LOW LEVEL MOIST LAYER ALONG
THE GEORGIA COAST WAS ENOUGH TO SUPPORT AREAS OF LIGHT RAIN WITHIN
A REGION OF ISENTROPIC ASCENT AND LOW LEVEL SPEED CONVERGENCE. WE
HAVE BUMPED UP POPS TO ACCOUNT FOR RADAR TRENDS. OTHERWISE...CLOUDS
REMAIN PREVALENT OVER OUR REGION WITH TEMPS IN THE MID 60S MOST
AREAS. NE WINDS WERE PICKING UP...MOST NOTICEABLE ALONG THE
COAST... ALREADY BLOWING 20-25 MPH WITH HIGHER GUSTS FROM PULASKI
TO SAPELO.
BLOCKING UPPER RIDGE EXTENDS FROM SE CANADA DOWN INTO THE CAROLINAS
TODAY KEEPING THE UPPER CUT-OFF LOW PRES OVER THE GULF COAST REGION
FROM ADVANCING TO THE NE TODAY. THIS LOW WILL TEND TO ADVANCE
IT/S WAY AROUND THE SOUTHERN PERIPHERY OF THE UPPER RIDGE AND THIS
TREND IN GOOD AGREEMENT ON THE 00Z MODEL RUN. THE MOST SIGNIFICANT
CHANGES WE HAVE MADE TODAY IS INCREASING CHANCES FOR WET WEATHER
ALONG AND TO THE S OF I-16. IF RADAR TRENDS CONTINUE TO DICTATE WE
MAY NEED TO INCREASE POPS FURTHER S OF A LINE FROM METTER TO
SAVANNAH...AND PARTICULARLY CLOSER TO THE ALTAMAHA RIVER AREA. A
DEEP MOISTURE GRADIENT EXTENDS THROUGH THIS REGION AND THESE
GEORGIA ZONES ARE RIGHT ALONG IT...MAKING POPS PROBLEMATIC SINCE
THERE COULD BE A FINE LINE BETWEEN A VERY WET DAY AND NO RAIN AT
ALL.
STRONG SURFACE HIGH PRES WEDGING DOWN THE LEE OF THE MOUNTAINS WILL
REMAIN ANCHORED TODAY AND WHEN SECONDARY LOW PRES IN THE BOUNDARY
LAYER BEGINS TO DEVELOP ACROSS CENTRAL FLORIDA LATER ON...WINDS
WILL BE QUITE STRONG AND GUSTY ALONG THE COAST. DEPENDENT ON THE
AMOUNT OF MESOSCALE PINCHING OF THE GRADIENT...WE COULD SEE SPEEDS
APPROACHING WIND ADVISORY CRITERIA FOR PARTS OF THE COAST FROM
BEAUFORT DOWN TO CHATHAM INTO MCINTOSH COUNTIES TODAY. ON AVERAGE
THE ONSHORE FLOW WILL BE IN THE 20-30 MPH RANGE WITH HIGHER GUSTS
TO THE E OF I-95 AND ESPECIALLY TO THE S OF EDISTO.
CLOUDS WILL PREVAIL BUT NAM/CMC OUTPUT SUGGESTS A BIT OF DRYING
COULD BRIEFLY SCATTER OUT LOWER CLOUDS IN THE CHARLESTON TRI-
COUNTY AREA LATE TODAY...WE HAVE NOT DEVIATED FROM MOSTLY CLOUDY N
TO CLOUDY S TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE DEEP MOISTURE GRADIENT DOES NOT MOVE MUCH TONIGHT WITH SOGGY
WEATHER CONTINUING JUST S OF THE ALTAMAHA REGION AND WE HAVE
MAINTAINED CHANCE POPS TO THE S OF I-16 BUT CONFIDENCE IS IFFY
ON HOW FAR N TO MAINTAIN ANY HIGHER POPS. BREEZY TO WINDY COASTAL
CONDITIONS WILL PERSIST AS WILL THE CLOUDS. LOW TEMPS AROUND 60 N
TO THE MID 60S COAST AND SOUTH.
AS AN IMPRESSIVE UPPER LOW DEEPENS/AMPLIFIES OVER THE CENTRAL
CONUS...THE UPPER LOW OVER THE NORTHERN GULF OF MEXICO/LOWER
MISSISSIPPI RIVER VALLEY WILL ADVANCE EAST AND OPEN TO A NEGATIVELY
TILTED UPPER TROUGH. AS THE BLOCKING HIGH TO THE NORTH BEGINS TO
WEAK AND SHIFT EAST...THIS ELONGATING UPPER TROUGH AND ASSOCIATED
BAND OF ENHANCED MOISTURE WILL GRADUALLY ADVANCE INTO THE REGION
FROM S/SW TO N/NE FRIDAY THROUGH SUNDAY...AND POPS SHOULD GENERALLY
INCREASE. DUE TO UNCERTAINTY REGARDING THE RATE OF RETREAT OF THE
BLOCKING HIGH AND ASSOCIATED RESISTANCE TO THE ADVANCE OF THE UPPER
TROUGH/MOISTURE...POPS DO NOT EXCEED 50 PERCENT FRIDAY AND SATURDAY.
HOWEVER...THESE POPS AND ASSOCIATED QPF COULD PROVE CONSERVATIVE...
ESPECIALLY IF PRECIPITATION COVERAGE EXPANDS IN RESPONSE TO DIURNAL
WARMING EACH DAY. THUS...HIGHER POPS/GREATER QPF COULD EVENTUALLY BE
REQUIRED...ESPECIALLY WITHIN NEAR TERM FORECASTS/UPDATES.
MEANWHILE...MODELS HAVE CLEARLY TRENDED TOWARD A SCENARIO FEATURING
THE MASSIVE UPPER LOW ROLLING EAST FROM THE PLAINS TOWARD THE EAST
COAST FRIDAY THROUGH SUNDAY. MODEL DEPICTION OF THE INTENSITY AND
TRACK OF THE UPPER LOW/ASSOCIATED COLD POOL DIFFERS AND THUS
DEGRADES FORECAST CONFIDENCE. OF PARTICULAR INTEREST...THE 02/00Z
EUROPEAN MODEL TRENDED TO A DEEPER UPPER LOW TRACKING FARTHER SOUTH
AND FASTER AS COMPARED TO EARLIER RUNS. IN THIS SCENARIO...THE UPPER
LOW WILL PUSH A COLD/OCCLUDED FRONT...PERHAPS EVEN A TRIPLE POINT
SURFACE LOW...INTO THE REGION AS EARLY AS SUNDAY AFTERNOON/
EVENING...ENHANCING THE POTENTIAL FOR PRECIPITATION INCLUDING
THUNDERSTORMS AND PERHAPS EVEN SUPPORTING SOME SEVERE WEATHER IF THE
UPPER COLD POOL/ASSOCIATED STEEPENING LAPSE RATES BEGIN TO
OVERSPREAD THE REGION. AS ALREADY MENTIONED...DUE TO FORECAST
UNCERTAINTY ARISING FROM MODEL DIFFERENCES AND LESS THAN IDEAL RUN
TO RUN MODEL CONSISTENCY...ADDED A MENTION OF THUNDER BUT ONLY
INDICATED CHANCE POPS SUNDAY.
STRONG/GUSTY ONSHORE WINDS WILL CONTINUE FRIDAY AND SATURDAY...THEN
WINDS SHOULD BEGIN TO SLACKEN SUNDAY. BELOW NORMAL TEMPERATURES...
INCLUDING HIGH TEMPERATURES IN THE 70S...WILL PREVAIL THROUGH THE
PERIOD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE DEEP UPPER LOW WILL CONTINUE TO ROLL EAST ACROSS THE REGION
THROUGH THE FIRST HALF OF NEXT WEEK AND SHOULD FINALLY SWING
NORTHEAST OF THE REGION BY THE END OF THE FORECAST PERIOD. SLOWER
MODEL SOLUTIONS DEPICT THE UPPER LOW PUSHING A COLD/OCCLUDED FRONT
THROUGH THE REGION AS LATE AS MONDAY...DELAYED FROM THE SUNDAY FROPA
DEPICTED BY THE 02/00Z EUROPEAN. THEN...THE REGION WILL REMAIN WITH
A DEEP LAYER CYCLONIC FLOW REGIME THROUGH MIDWEEK. OF SPECIAL
INTEREST...AN UNSEASONABLY INTENSE COLD POOL ALOFT...FEATURING
500 MB TEMPERATURES AS COLD AS -18C TO -23C...COLDEST ACROSS
NORTHERN COUNTIES...AND THE POTENTIAL FOR MESOSCALE BOUNDARIES/
CONVERGENCE WITHIN THE LOW LEVEL CYCLONIC FLOW REGIME COULD SUPPORT
DIURNAL THUNDERSTORMS AND AN ENHANCED THREAT FOR LARGE HAIL. POPS
COULD BELOW NORMAL TEMPERATURES ARE LIKELY TO PREVAIL THROUGH
MIDWEEK.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
EXPECT SUB-VFR CONDITIONS INTO LATE MORNING AND POSSIBLY INTO THIS
AFTERNOON AT KSAV. LATEST MODEL SOUNDINGS INDICATE A BIT OF A DRIER
PUNCH IN THE CLOUD LAYER RH FIELDS TO LIFT CIGS TO ABOVE 3 FT AT
KCHS THIS AFTERNOON BUT KSAV IS RIGHT ON A STRONG DEEPER LAYERED
MOISTURE GRADIENT AND THE FORECAST FOR CIG HEIGHTS REMAINS TRICKY.
WE WILL CARRY VCSH AT KSAV UNTIL RADAR TRENDS DICTATE. WE HAVE
RAMPED ONSHORE SURFACE WINDS UP TO 20G27 KT AT KSAV AS A WINDY
DAY IS ON TAP.
EXTENDED AVIATION OUTLOOK...PERIODS OF FLIGHT RESTRICTIONS...MOSTLY
DUE TO SUB-VFR CEILINGS...WILL ALTERNATE WITH PERIODS OF VFR
CONDITIONS THROUGH THE PERIOD.
&&
.MARINE...
WINDS AND SEAS ON THE INCREASE EARLY THIS MORNING WITH SOLID SMALL
CRAFT ADVISORY CONDITIONS ALL WATERS WITH THE CHARLESTON HARBOR
CLOSER TO 15 TO 20 KT AT 08Z. MODEL TRENDS FAVOR A 35 TO 40 KT
ONSHORE LOW LEVEL JET DEVELOPING TO THE S OF EDISTO BEACH AS THE
925 MB GRADIENT PINCHES BETWEEN THE STRONG HIGH TO THE N AND LOWER
PRES OVER FLORIDA. A TRICKY FORECAST AS MESOSCALE JETTING AND
PINCHING OF THE LOW LEVEL GRADIENT SEEMS OBVIOUS BUT THE PROBLEM
OF WHEN AND WHERE REMAIN DIFFICULT TO PINPOINT. THERE WAS ENOUGH
EVIDENCE IN THE MODEL FIELDS TO UPGRADE OUR GALE WATCH TO A
WARNING ALONG THE FAR SOUTHERN SOUTH CAROLINA COAST AND ALL
GEORGIA WATERS.
A TIGHT PRESSURE GRADIENT WILL MAINTAIN STRONG ONSHORE WINDS AND
HAZARDOUS SEAS FRIDAY THROUGH SATURDAY. GALE WARNINGS CONTINUE
INTO SATURDAY FOR WATERS SOUTH OF EDISTO BEACH...AND AT LEAST HIGH
END SMALL CRAFT ADVISORY CONDITIONS WILL PREVAIL ACROSS NORTHERN
SC WATERS. FORECAST ADJUSTMENTS COULD BE REQUIRED DUE TO A
PRESSURE GRADIENT WHICH WILL LIKELY CHANGE MAGNITUDE AND SHIFT
POSITION.
AS THE HIGH PRESSURE CENTERED NORTH OF THE REGION BEGINS TO
WEAKEN...WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AND
SUNDAY...BUT SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY PERSIST ALL
AREAS THROUGH THE WEEKEND. THEN...WINDS WILL DIMINISH SIGNIFICANTLY
AND SEAS WILL SUBSIDE BELOW 6 FT ALL WATERS EARLY NEXT WEEK.
RIP CURRENTS...SUBTLE LONG PERIOD SWELL WITH STRONG ONSHORE WINDS
JUSTIFIES CONTINUING THE MODERATE RISK OF RIP CURRENTS TODAY.
INCREASING SURF AND ROUGH SEAS WILL OTHERWISE MAKE FOR NASTY
CONDITIONS FOR ANYONE IN THE WATERS AS THE LONGSHORE CURRENT
STRENGTHENS. THE ELEVATED RIP CURRENT RISK WILL PREVAIL THROUGH
THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
THE POTENTIAL FOR BREAKERS UP TO 4 TO 6 FT THIS AFTERNOON AND
BEYOND WAS HIGH ENOUGH TO WARRANT THE ISSUANCE OF A HIGH SURF
ADVISORY ALONG THE GEORGIA COAST STARTING AT 15Z TODAY.
HIGH SURF POTENTIAL ALONG THE GEORGIA COAST WILL LINGER THROUGH
SAT. TIDAL DEPARTURES WILL BE 1 TO 2 FT ALONG OUR SOUTHERN COAST
HIGHEST WITH WATER HELD IN AT LOW TIDES. AT THIS TIME...SHALLOW
COASTAL FLOODING IS UNLIKELY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...HIGH SURF ADVISORY FROM 11 AM THIS MORNING TO 5 PM EDT
SATURDAY FOR GAZ117-119-139-141.
SC...NONE.
MARINE...GALE WARNING UNTIL 1 PM EDT SATURDAY FOR AMZ352-354.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR AMZ350.
GALE WARNING UNTIL 6 PM EDT SATURDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT SATURDAY NIGHT FOR
AMZ330.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...SPR
LONG TERM...SPR
AVIATION...
MARINE...SPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
357 AM CDT THU MAY 2 2013
...UPDATED LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1038 PM CDT WED MAY 1 2013
THE 02.00Z 250 HPA RAOB MAP SHOWED STRONG FLOW ACROSS THE ROCKIES AND
ACROSS THE NORTHERN PLAINS ASSOCIATED WITH A LARGE SCALE TROF. MAGNITUDES
WERE AROUND 100 KT. STRONGER FLOW OF 130 KT WAS NOTED ACROSS WESTERN
ONTARIO. AT 500 HPA, A VERY IMPRESSIVE FOR 02 MAY COLD POOL OF -30 DEG
C TO -33 DEG C WAS NOTED ACROSS MONTANA AND WYOMING. THIS WAS ASSOCIATED
WITH THE AFOREMENTIONED TROF. AT 700 HPA, AN IMPRESSIVE TEMPERATURE
GRADIENT BETWEEN KDDC (+3 DEG C) AND KLBF (-8 DEG C) WAS NOTED. FARTHER
UPSTREAM, MID LEVEL TEMPERATURES WERE EVEN COLDER WITH -15 DEG C AT
KGGW AT -18 DEG C AT CYQD. AT 850 HPA, THE AMOUNT OF COLD AIR ADVECTION
BETWEEN 00Z SYNOPTIC FLIGHTS WAS TREMENDOUS (25 DEG C TO -3 DEG C AT
KDDC). IN FACT, THE OBSERVED VALUE OF -2.8 DEG C IS WELL BELOW 2 STANDARD
DEVIATIONS AND CLOSER TO THE MINIMUM OF -5 DEG C FOR 850 HPA STATISTICS.
THIS IS OBVIOUSLY AT THE TAIL END OF EXTREMES FOR A GAUSSIAN DISTRIBUTION.
AT THE SURFACE, A STRONG COLD FRONT HAD PUSHED WELL SOUTH OF THE REGION.
A 1038 HPA ANTICYCLONE WAS BUILDING IN THE WAKE OF THE FRONT ACROSS
THE HIGH PLAINS. WSR-88D RADAR MOSAIC SHOWED SNOW ACROSS NW KANSAS AND
CONVECTION ACROSS SC KANSAS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT THU MAY 2 2013
BUSY MORNING WITH NUMEROUS SENSIBLE WEATHER IMPACTS AND RESULTANT
GRID MODIFICATIONS.
THIS MORNING:
KDDC WSR-88D REFLECTIVITY AND SURFACE OBSERVATIONS CONTINUE TO INDICATE
A BAND OF SNOW MOVING ACROSS WESTERN KANSAS EARLY THIS MORNING. A QUICK
LOOK AT KDOT CAMERAS DO SHOW THAT SOME OF THE SNOW IS STICKING TO THE
ROADWAYS ACROSS THE INTERSTATE 70 CORRIDOR. AFTER CHECKING NAM/WRF/RAP/AND
HRRR MODELS, IT APPEARS THAT THE HRRR IS DOING THE BETTER JOB WITH SNOW
FORECASTS COMPARED WITH ACTUAL LSR`S UPSTREAM. AS A RESULT, HEAVILY
BIASED THE NEAR TERM FORECAST TO HRRR OUTPUT SOLUTIONS. THE SNOW IS
IN ASSOCIATION WITH A TIGHT 700 HPA BAROCLINIC AS WELL AS THE PASSAGE
AND RESULTANT SYNOPTIC FORCING OF A 250 HPA JET STREAK (RIGHT ENTRANCE
REGION). HAVE ISSUED A WINTER WEATHER ADVISORY FOR NW/N PORTIONS OF
THE FORECAST AREA OF RESPONSIBILITY. MOST ACCUMULATION SHOULD BE ON
GRASSY/ELEVATED SURFACES, BUT IT WOULD NOT TAKE MUCH TO GET TEMPORARY
HAZARDOUS TRAVEL CONDITIONS. THIS IS TRULY AN IMPRESSIVE EVENT WITH
CURRENT OBSERVATIONS. FOR OTHER RELATED INFORMATION, SEE THE SYNOPSIS
AND WSW.
ELSEWHERE, MINIMUM TEMPERATURES FOR THIS MORNING APPEAR TO BE ON TRACK
AND WILL CONTINUE THE FREEZE WARNING AS IS.
TODAY:
TODAY WILL BE COLD WITH MAXIMUM TEMPERATURES IN THE 40S. STRATUS WILL
STICK AROUND FOR THE FIRST HALF OF TODAY SO TEMPERATURES WILL NOT GET
THE CHANCE TO CLIMB. THE COLDEST TEMPERATURES ARE FORECAST ACROSS SC
KANSAS WHERE CLOUDS AND PRECIPITATION WILL RESIDE LONGER. THE OTHER
CONCERN FOR TODAY IS WINDS. 850 HPA WINDS AROUND 50 KT AND A TIGHT PRESSURE
GRADIENT DO SPELL OUT THE CONCERN FOR A WIND ADVISORY GENERALLY SOUTH
OF THE ARKANSAS RIVER. HAVE ISSUED AS A RESULT WITH THE NAM SHOWING
WIND ADVISORY CRITERIA FOR THE SOUTHERN ROW OF COUNTIES EXCEPT MORTON
COUNTY.
TONIGHT:
THE MAIN SYNOPTIC WAVE WILL BE EAST OF THE REGION BY LATE TONIGHT. SUBSIDENCE
AND DRY AIR ADVECTION IS EXPECTED IN THE WAKE OF THE TROF. HIGH PRESSURE
WILL BUILD AT THE SURFACE WITH WINDS BECOMING LIGHT. HAVE UPGRADED THE
TWO WATCHES TO WARNINGS WITH A HARD FREEZE WARNING COVERING MUCH OF
THE FORECAST AREA OF RESPONSIBILITY EXCEPT ACROSS PORTIONS OF SC KANSAS
WHERE MINIMUMS WILL BE SLIGHTLY MORE "MILD". STILL, WE ARE LOOKING AT
VERY COLD LOWS WITH MINIMUMS MAINLY IN THE 20S DEG F.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 356 AM CDT THU MAY 2 2013
BY FRIDAY MORNING, THE DEEP UPPER TROUGH OVER THE NORTHERN AND
CENTRAL PLAINS WILL BE CLOSING OFF INTO AN UPPER LOW CENTERED ALONG
THE BORDER OF SOUTHEAST KANSAS AND NORTHEAST OKLAHOMA. FROM THERE,
THE MEDIUM RANGE MODELS MOVE THE LOW EAST ALONG THE BORDER OF
MISSOURI AND ARKANSAS THROUGH SATURDAY. THE MODELS ARE SHOWING A
LOBE OF VORTICITY ROTATING AROUND THE NORTH SIDE OF THE UPPER LOW
AND BACK INTO CENTRAL AND PARTS OF WESTERN KANSAS ON SATURDAY. THE
NAM AND GFS ARE SHOWING SOME LIGHT PRECIPITATION SPREADING INTO
CENTRAL AND PARTS OF WESTERN KANSAS DURING THE DAY SATURDAY AS WELL.
THE UKMET ALSO SHOWS THIS WHILE THE ECMWF AND GEM ARE NOT AS
AGGRESSIVE. IN COLLABORATION WITH SURROUNDING OFFICES, HAVE BUMPED
UP POPS FOR LIGHT RAIN SOMEWHAT DURING THE DAY SATURDAY WITH POPS
TAPERING OFF BY SATURDAY EVENING.
WE SHOULD HAVE A FEW DAYS OF DRY WEATHER DURING THE EARLY PART OF
NEXT WEEK AS THE CLOSED UPPER LOW CONTINUES TO MOVE INTO THE
SOUTHEASTERN STATES AND WEAK UPPER LEVEL RIDGING DOMINATES THE
CENTRAL PLAINS. THE MODELS TEND TO AGREE THAT ANOTHER UPPER LOW WILL
FORM OVER THE NORTHERN ROCKIES AND DIG SOUTHWESTWARD TO JUST OFF THE
CALIFORNIA COAST BY SUNDAY EVENING. AFTER THIS TIME THE MODELS
REALLY DIVERGE WITH HOW THIS SYSTEM EVOLVES AND MOVES EASTWARD
TOWARD THE PLAINS BUT ALL THE MODELS ARE MORE OR LESS SHOWING AN
INITIAL PIECE OF ENERGY EJECTING OUT TOWARD THE CENTRAL PLAINS AND
INCREASING CHANCES FOR SHOWERS ACROSS WESTERN KANSAS BY MONDAY NIGHT
AND TUESDAY. THE MAIN UPPER LOW OPENS UP SOMEWHAT AS IT MOVES OUT
OVER THE CENTRAL PLAINS THROUGH THE MIDDLE PART OF NEXT WEEK. THE
LATEST ALLBLEND HAS SLIGHT CHANCE OR CHANCE POPS THROUGH THE MIDDLE
PART OF NEXT WEEK. SUFFICE IT TO SAY THAT IT IS DIFFICULT TO NARROW
DOWN ANY SPECIFIC DAYS THAT PRECIPITATION CHANCES WILL BE THE BEST
DURING THAT TIME PERIOD GIVEN THE MODEL DIFFERENCES SO WILL KEEP
CHANCES FOR PRECIPITATION IN THE FORECAST THROUGH THURSDAY BEFORE
CHANCES SHOULD BE DECREASING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1200 AM CDT THU MAY 2 2013
POOR FLIGHT CONDITIONS WITH IFR CIGS EXPECTED THROUGH THE OVERNIGHT
HOURS IN ASSOCIATION WITH -SN AND LOW STRATUS. SYSTEM WILL EXIT OUT
OF THE REGION THROUGH THE AFTERNOON WITH FLIGHT CONDITIONS IMPROVING
WITH TIME. WINDS WILL BE NORTHERLY 20-30 KT THROUGH MOST OF THE TAF
PD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 46 27 56 34 / 50 0 10 10
GCK 47 26 58 33 / 30 0 0 10
EHA 46 27 60 36 / 30 0 0 0
LBL 46 25 59 35 / 50 0 0 0
HYS 47 27 52 34 / 40 0 10 20
P28 44 31 54 36 / 100 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM 11 PM CDT /10 PM MDT/ THIS EVENING TO 1
PM CDT /NOON MDT/ FRIDAY FOR KSZ030-031-043>046-061>065-074>078-
084>087.
WINTER WEATHER ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ030-
043>045.
FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
KSZ030-031-043>046-061>065-074>080-084>088.
FREEZE WARNING FROM 11 PM THIS EVENING TO 1 PM CDT FRIDAY FOR
KSZ066-079>081-088>090.
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ085>090.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...GERARD
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
309 AM CDT THU MAY 2 2013
...UPDATE TO SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1038 PM CDT WED MAY 1 2013
THE 02.00Z 250 HPA RAOB MAP SHOWED STRONG FLOW ACROSS THE ROCKIES AND
ACROSS THE NORTHERN PLAINS ASSOCIATED WITH A LARGE SCALE TROF. MAGNITUDES
WERE AROUND 100 KT. STRONGER FLOW OF 130 KT WAS NOTED ACROSS WESTERN
ONTARIO. AT 500 HPA, A VERY IMPRESSIVE FOR 02 MAY COLD POOL OF -30 DEG
C TO -33 DEG C WAS NOTED ACROSS MONTANA AND WYOMING. THIS WAS ASSOCIATED
WITH THE AFOREMENTIONED TROF. AT 700 HPA, AN IMPRESSIVE TEMPERATURE
GRADIENT BETWEEN KDDC (+3 DEG C) AND KLBF (-8 DEG C) WAS NOTED. FARTHER
UPSTREAM, MID LEVEL TEMPERATURES WERE EVEN COLDER WITH -15 DEG C AT
KGGW AT -18 DEG C AT CYQD. AT 850 HPA, THE AMOUNT OF COLD AIR ADVECTION
BETWEEN 00Z SYNOPTIC FLIGHTS WAS TREMENDOUS (25 DEG C TO -3 DEG C AT
KDDC). IN FACT, THE OBSERVED VALUE OF -2.8 DEG C IS WELL BELOW 2 STANDARD
DEVIATIONS AND CLOSER TO THE MINIMUM OF -5 DEG C FOR 850 HPA STATISTICS.
THIS IS OBVIOUSLY AT THE TAIL END OF EXTREMES FOR A GAUSSIAN DISTRIBUTION.
AT THE SURFACE, A STRONG COLD FRONT HAD PUSHED WELL SOUTH OF THE REGION.
A 1038 HPA ANTICYCLONE WAS BUILDING IN THE WAKE OF THE FRONT ACROSS
THE HIGH PLAINS. WSR-88D RADAR MOSAIC SHOWED SNOW ACROSS NW KANSAS AND
CONVECTION ACROSS SC KANSAS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT THU MAY 2 2013
BUSY MORNING WITH NUMEROUS SENSIBLE WEATHER IMPACTS AND RESULTANT
GRID MODIFICATIONS.
THIS MORNING:
KDDC WSR-88D REFLECTIVITY AND SURFACE OBSERVATIONS CONTINUE TO INDICATE
A BAND OF SNOW MOVING ACROSS WESTERN KANSAS EARLY THIS MORNING. A QUICK
LOOK AT KDOT CAMERAS DO SHOW THAT SOME OF THE SNOW IS STICKING TO THE
ROADWAYS ACROSS THE INTERSTATE 70 CORRIDOR. AFTER CHECKING NAM/WRF/RAP/AND
HRRR MODELS, IT APPEARS THAT THE HRRR IS DOING THE BETTER JOB WITH SNOW
FORECASTS COMPARED WITH ACTUAL LSR`S UPSTREAM. AS A RESULT, HEAVILY
BIASED THE NEAR TERM FORECAST TO HRRR OUTPUT SOLUTIONS. THE SNOW IS
IN ASSOCIATION WITH A TIGHT 700 HPA BAROCLINIC AS WELL AS THE PASSAGE
AND RESULTANT SYNOPTIC FORCING OF A 250 HPA JET STREAK (RIGHT ENTRANCE
REGION). HAVE ISSUED A WINTER WEATHER ADVISORY FOR NW/N PORTIONS OF
THE FORECAST AREA OF RESPONSIBILITY. MOST ACCUMULATION SHOULD BE ON
GRASSY/ELEVATED SURFACES, BUT IT WOULD NOT TAKE MUCH TO GET TEMPORARY
HAZARDOUS TRAVEL CONDITIONS. THIS IS TRULY AN IMPRESSIVE EVENT WITH
CURRENT OBSERVATIONS. FOR OTHER RELATED INFORMATION, SEE THE SYNOPSIS
AND WSW.
ELSEWHERE, MINIMUM TEMPERATURES FOR THIS MORNING APPEAR TO BE ON TRACK
AND WILL CONTINUE THE FREEZE WARNING AS IS.
TODAY:
TODAY WILL BE COLD WITH MAXIMUM TEMPERATURES IN THE 40S. STRATUS WILL
STICK AROUND FOR THE FIRST HALF OF TODAY SO TEMPERATURES WILL NOT GET
THE CHANCE TO CLIMB. THE COLDEST TEMPERATURES ARE FORECAST ACROSS SC
KANSAS WHERE CLOUDS AND PRECIPITATION WILL RESIDE LONGER. THE OTHER
CONCERN FOR TODAY IS WINDS. 850 HPA WINDS AROUND 50 KT AND A TIGHT PRESSURE
GRADIENT DO SPELL OUT THE CONCERN FOR A WIND ADVISORY GENERALLY SOUTH
OF THE ARKANSAS RIVER. HAVE ISSUED AS A RESULT WITH THE NAM SHOWING
WIND ADVISORY CRITERIA FOR THE SOUTHERN ROW OF COUNTIES EXCEPT MORTON
COUNTY.
TONIGHT:
THE MAIN SYNOPTIC WAVE WILL BE EAST OF THE REGION BY LATE TONIGHT. SUBSIDENCE
AND DRY AIR ADVECTION IS EXPECTED IN THE WAKE OF THE TROF. HIGH PRESSURE
WILL BUILD AT THE SURFACE WITH WINDS BECOMING LIGHT. HAVE UPGRADED THE
TWO WATCHES TO WARNINGS WITH A HARD FREEZE WARNING COVERING MUCH OF
THE FORECAST AREA OF RESPONSIBILITY EXCEPT ACROSS PORTIONS OF SC KANSAS
WHERE MINIMUMS WILL BE SLIGHTLY MORE "MILD". STILL, WE ARE LOOKING AT
VERY COLD LOWS WITH MINIMUMS MAINLY IN THE 20S DEG F.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 317 PM CDT WED MAY 1 2013
VERY COLD TEMPERATURES FOR THIS TIME OF THE YEAR ARE EXPECTED FRIDAY
MORNING AS THE UPPER LEVEL LOW MOVES INTO EASTERN KANSAS AND SKIES
BECOME MOSTLY CLEAR. LOWS FRIDAY MORNING ARE FORECASTED TO DIP BELOW
FREEZING ACROSS ALL OF WESTERN KANSAS. A FREEZE WARNING CONTINUES
EAST AND SOUTH OF A LINE FROM LARNED TO MEADE AND A HARD FREEZE
WATCH NORTH AND WEST OF THIS LINE.
MODELS THEN BECOME IN SOMEWHAT DISAGREEMENT ON THE TRACK OF THE
UPPER LEVEL LOW THIS WEEKEND. ALL MODELS HAVE IT SPINNING INTO THE
MISSISSIPPI VALLEY BY SUNDAY. HOWEVER, THE GEM PLACES IT ACROSS THE
UPPER MISSISSIPPI VALLEY, THE ECMWF ACROSS THE MID MISSISSIPPI
VALLEY, AND THE GFS A LITTLE FARTHER SOUTH ACROSS ARKANSAS AND
TENNESSEE. NEVERTHELESS, THIS LOW WILL AFFECT PORTIONS OF CENTRAL
AND SOUTH CENTRAL KANSAS AS MID LEVEL MOISTURE WRAPS AROUND IT
BRINGING AN INCREASE IN CLOUDS. SOME PRECIPITATION WILL BE POSSIBLE
ACROSS WICHITA`S FORECAST AREA DURING THIS TIME FRAME BUT HAVE
ELECTED TO LEAVE IT OUT OF OUR FORECAST AREA FOR THE TIME BEING.
FARTHER WEST, AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL BE BUILDING
ACROSS THE ROCKIES FRIDAY THROUGH SUNDAY. A DOME OF HIGH PRESSURE
WILL BE FOUND ACROSS THIS AREA AT THE SURFACE, AND WITH THE
ATMOSPHERIC COULOMB BEING FAIRLY DRY, PARTLY CLOUDY SKIES AND DRY
CONDITIONS ARE FORECASTED ACROSS THE REMAINDER OF THE CWA. WINDS
FRIDAY THROUGH SATURDAY NIGHT WILL GENERALLY BE FROM THE NORTH TO
NORTHWEST SHIFTING TO THE NORTHEAST ON SUNDAY.
MEANWHILE, AN UPPER LEVEL LOW WILL BE FORMING ACROSS THE DESERT
SOUTHWEST AND EASTERN PACIFIC OCEAN FRIDAY THROUGH SUNDAY. THIS LOW
IS THEN ANTICIPATED TO SHIFT EASTWARD DURING THE BEGINNING OF NEXT
WEEK AND FLATTEN OUT THE UPPER LEVEL RIDGE. AS THIS SYSTEM
APPROACHES, LEE TROUGHING WILL DEVELOP SHIFTING WINDS TO THE SOUTH
AND BRINGING BACK MID TO LOW LEVEL MOISTURE TO WESTERN KANSAS.
THUNDERSTORM CHANCES INCREASE MONDAY NIGHT INTO THE MIDDLE PART OF
NEXT WEEK. HOWEVER, WITH THIS SYSTEM BEING OUT ON DAY 6 AND 7,
CHANGES WILL MOST LIKELY BE MADE AS FUTURE MODEL RUNS BRING IN
DIFFERENT SOLUTIONS.
AS FOR TEMPERATURES, A GENERAL WARM UP IS EXPECTED THIS WEEKEND INTO
THE BEGINNING OF NEXT WEEK. HIGHS START OUT IN THE 50S AND LOWER 60S
FRIDAY AFTERNOON THEN INCREASE INTO THE 70S BY EARLY NEXT WEEK. LOWS
START OUT IN THE 30S SATURDAY MORNING THEN INCREASE INTO THE UPPER
40S AND LOWER 50S BY TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1200 AM CDT THU MAY 2 2013
POOR FLIGHT CONDITIONS WITH IFR CIGS EXPECTED THROUGH THE OVERNIGHT
HOURS IN ASSOCIATION WITH -SN AND LOW STRATUS. SYSTEM WILL EXIT OUT
OF THE REGION THROUGH THE AFTERNOON WITH FLIGHT CONDITIONS IMPROVING
WITH TIME. WINDS WILL BE NORTHERLY 20-30 KT THROUGH MOST OF THE TAF
PD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 46 27 56 34 / 50 0 10 10
GCK 47 26 58 33 / 30 0 0 10
EHA 46 27 60 36 / 30 0 0 0
LBL 46 25 59 35 / 50 0 0 0
HYS 47 27 52 34 / 40 0 10 20
P28 44 31 54 36 / 100 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM 11 PM CDT /10 PM MDT/ THIS EVENING TO 1
PM CDT /NOON MDT/ FRIDAY FOR KSZ030-031-043>046-061>065-074>078-
084>087.
WINTER WEATHER ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ030-
043>045.
FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
KSZ030-031-043>046-061>065-074>080-084>088.
FREEZE WARNING FROM 11 PM THIS EVENING TO 1 PM CDT FRIDAY FOR
KSZ066-079>081-088>090.
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ085>090.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...HOVORKA_42
AVIATION...SUGDEN
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1206 AM CDT THU MAY 2 2013
.UPDATE...
ISSUED AT 1011 PM CDT WED MAY 1 2013
THE POTENT COLD FRONT IS MAKING GOOD PROGRESS INTO THE NWRN
PORTION OF THE CWA AND AT 03Z WAS BI-SECTING LEWIS AND SHELBY
COUNTIES...THEN TRAILED PASS MOBERLY AND INTO WESTERN COOPER
COUNTY. THE PUSH/PROGRESS WAS QUITE A BIT AHEAD OF THE PREVIOUS
FORECAST AND A QUICK LOOK AT THE NEW NAM AND RECENT RUC SUGGEST IT
WILL CONTINUE ITS S/SEWD MARCH. THIS NECESSITATED QUITE A FEW
CHANGES IN THE TONIGHT AND THURSDAY GRIDS TO SPEED THINGS UP DUE
TO THE PREVIOUSLY SLOW FRONTAL PROGRESS. OTHERWISE...THE MAIN
AREA OF RAIN WILL REMAIN WEST OF THE CWA TONIGHT...DEEP INTO THE
COLD AIR. HOWEVER SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS
WILL BE POSSIBLE IN A CORRIDOR AHEAD OF THE COLD FRONT AND IN THE
WAKE OF THE COLD FRONT IN RESPONSE TO LOW LEVEL WAA/MOISTURE
CONVERGENCE VIA SELY LOW LEVEL FLOW.
GLASS
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 405 PM CDT WED MAY 1 2013
EWD PUSH OF STRONG COLD FRONT ACROSS AREA WILL CONTINUE TO BE AT A
SNAILS PACE OVERNIGHT. HAVE GONE WITH A CONSENSUS OF
LOCALWRF...NAM...AND SREF FOR ITS MOVEMENT...WHICH SUGGESTS FRONT
WILL BE CREEPING THROUGH UIN AND COU AREAS DURING THE PREDAWN HOURS.
OBVIOUSLY OVERNIGHT LOWS WILL BE DETERMINED BY THE EARLY MORNING
FRONTAL POSITION....BUT IN GENERAL HAVE LEANED TOWARDS THE WARMER
GUIDANCE DUE TO THE SLOW FRONTAL MOVEMENT.
SPOTTY AMS CONVECTION OVER E OZARKS/S IL SHOULD BE DISSIPATING OVER
THE NEXT FEW HOURS. WE THEN HAVE INTRODUCED SOME SLIGHT CHANCE POPS
OVER NW SECTIONS OF THE CWA LATER THIS EVENING AND OVERNIGHT AS NAM
FORECAST SOUNDINGS ARE INDICATING A WINDOW OF OPPORTUNITY FOR SOME
ELEVATED CONVECTION IN THE VICINITY OF THE FRONT...BUT IN GENEARL
THINK THAT MOST OF THE AREA WILL BE IN FOR A RATHER LONG WAIT UNTIL
THE MORE SIGNIFICANT PRECIPITATION MOVES IN.
TRUETT
.LONG TERM...(THURSDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 400 PM CDT WED MAY 1 2013
UNUSUAL WX PATTERN FOR EARLY MAY AS THE UPPER LEVEL TROUGH OVER THE
NRN PLAINS DEEPENS...EVENTUALLY CUTTING OFF OVER THE PLAINS THU NGT
AND DEEPENS FRI AND FRI NGT. THE MODELS STILL DIFFER ON THE
POSITION AND TRACK OF THE UPPER LEVEL LOW WITH THE GFS FURTHER S
COMPARED TO THE NAM AND ECMWF MODELS. THE STRONG COLD FRONT WILL
MOVE SLOWLY SEWD THROUGH OUR FORECAST AREA ON THU AS THE UPPER LEVEL
TROUGH DEEPENS OVER THE PLAINS. IT APPEARS THAT MOST OF THE
PRECIPITATION WILL CONTINUE TO BE POST FRONTAL WITH THE CHANCE OF
RAIN GRADUALLY INCREASING FROM NW TO SE ON THU WITH THE PROGRESSION
OF THE FRONT. TEMPERATURES SHOULD FALL DURING THE AFTN ACROSS MOST
OF OUR AREA...EXCEPT SWRN IL AS COLDER AIR FILTERS SEWD INTO THE
REGION BEHIND THE FRONT ALONG WITH LOW LEVEL CLOUD COVER AND
FAIRLY WIDESPREAD PRECIPITATION. SHOULD HAVE WIDESPREAD AND
POSSIBLY HEAVY RAINS THU NGT AND FRI AS THE UPPER LEVEL LOW
DEVELOPS AND DEEPENS W OF OUR AREA AND CAUSES A SFC LOW TO DEVELOP
ALONG THE FRONT. WILL ISSUE A HDROLOGIC OUTLOOK FOR MAINLY THE
PERIOD FROM THU NGT THROUGH FRI NGT AS RAINFALL AMOUNTS OF 1 TO 2
INCHES ARE EXPECTED WITH LOCALLY HIGHER AMOUNTS WHICH COULD LEAD
TO SOME FLOOD POTENTIAL AND RIVERS AND CREEKS COMING UP TO
BANKFULL. THE NAM MODEL APPEARS A LITTLE TOO COLD ON TEMPERATURES
THU NGT THROUGH FRI NGT AND FOR NOW WILL GO WITH A BLEND OF NAM
AND GFS MOS GUIDANCE. EVEN SO WE WILL EXPERIENCE MUCH COOLER
TEMPERATURES FOR THU NGT THROUGH FRI NGT AND WELL BELOW NORMAL FOR
EARLY MAY. THE BETTER THREAT FOR PRECIPITATION SHOULD SHIFT EWD
INTO IL FRI NGT AS A DRY SLOT MOVES N-NEWD INTO PORTIONS OF CNTRL
AND SERN MO. THE PRECIPITATION WILL LIKELY BE MORE SCATTERED AND
POSSIBLY LIGHTER ON SAT AS THE UPPER LEVEL LOW AND ASSOCIATED
OCCLUDED SFC LOW MOVES SLOWLY THROUGH SWRN MO PER THE NAM AND
ECMWF FORECASTS...THE GFS MODEL APPEARS A LITTLE TOO FAR S WITH
TRACK OF UPPER LEVEL LOW. WITH HAVE LINGERING SHOWERS SAT NGT AND
SUN AS THE UPPER LEVEL LOW MOVES SLOWLY EWD THROUGH SERN MO AND
SRN IL WITH CONTINUED UNSEASONABLY COLD TEMPERATURES. WILL BEGIN
TO SEE A WARMING TREND FOR THE EARLY PORTION OF THE NEXT WORK WEEK
AS THE UPPER LEVEL LOW FINALLY MOVES WELL E OF OUR AREA.
GKS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1150 PM CDT WED MAY 1 2013
LATEST SURFACE ANAYLSIS SHOWS COLD FRONT MOVING MUCH FASTER TO THE
SOUTHEAST FROM EARLIER FORECASTS. COLD FRONT HAS ALREADY MOVED
SOUTH OF UIN AND VERY NEAR COU. EXPECT FROMO COLD FRONT TO MOVE
ACROSS THE ST. LOUIS AREA BETWEEN 1100-1300 UTC. CIGS WILL BE
DROPPING FROM DAYBREAK THROUGH MID DAY. EXPECT RAIN AND FOG TO
DEVELOP OVER COU BEFORE DAYBRAK AND OVER STL-SUS-UIN AREA DURING
LATE MORNING AND CONTINUE TO AFTERNOON HOURS. WINDS WILL BE
NORTHERLY 10 TO 12 KTS WITH GUSTS TO 14KTS FROM THE NORTH.
SPECIFICS FOR KSTL..CIGS WILL BE DROPPINJG TO 5 KFT AFTER 0900 UTC
AND 3 KFT AFTER 1000 UTC. WINDS WILL BE FROM THE SOUTHEAST AT
AROUND 7 KTS THEN AFTER PASSAGE OF COLD FRONT AROUND 1100 UTC
WINDS WILL SHIFT TO THE NORTH WITH SPEEDS OF 10 KTS AND POSSIBLE
GUSTS TO 14 KTS. RAINSHOWERS AND FOG WILL SETTLE OVER AREA AFTER
1500 UTC. LOW CIGS BELOW 1 KFT WILL OCCUR FROM MID AFTERNOON
THROUGH EVENING HOURS.
PRZYBYLINSKI
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS TULSA OK
1155 PM CDT WED MAY 1 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL BE BRIEF ACROSS ERN OK TAF SITES...BUT PERSIST INTO
THE OVERNIGHT AT THE REMAINING SITES. ONCE THE STRONG COLD FRONT
SWEEPS ACROSS THE ENTIRE AREA...MVFR AND IFR CIGS ARE EXPECTED BEHIND THE
FRONT ALONG WITH SCATTERED SHOWERS...AND PERHAPS AN ISOLATED
THUNDERSTORM. GUSTY NW WINDS WILL PERSIST ONCE THE FRONT PASSES.
AREAL COVERAGE OF RAIN WILL INCREASE WITH TIME FROM WEST TO
EAST...HOWEVER,,,THE HIGHEST RAINFALL COVERAGE IS EXPECTED TO
REMAIN ACROSS ERN OK FOR MUCH OF THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 851 PM CDT WED MAY 1 2013/
DISCUSSION...
STORMS DEVELOPED WEST AND NORTH OF TULSA DURING PEAK HEATING IN AN
ENVIRONMENT THAT MORE CLOSELY RESEMBLES WHAT YOU WOULD SEE IN THE
SUMMER RATHER THAN THE FIRST OF MAY. THEY WERE PULSE IN
NATURE...AND WHAT IS LEFT OF THEM IS MOVING NORTH OVER OSAGE
COUNTY AT THE MOMENT. THE COLD FRONT HAS UNDERCUT THE STORMS...AND
MAY PROVIDE SOME TEMPORARY LIFT TO KEEP THEM GOING.
HOWEVER...SINCE THE MAIN ENERGY SOURCE HAS SET FOR THE NIGHT...I
THINK THESE STORMS WILL SEE THEIR DEMISE SOON. THE LATEST RUN OF
THE HRRR AND THE 18Z NAM BOTH SUGGEST IT WILL BE FAIRLY QUIET
ALONG THE SURGING FRONT TONIGHT. THE POTENT PV ANOMALY OVER
WESTERN CO IS STILL WELL WEST TONIGHT...AND LIFT FROM THIS SYSTEM
WILL NOT OVERSPREAD THE REGION TILL TOMORROW. THE HRRR SHOWS THE
POST-FRONTAL BAND OF PRECIP MOVING INTO NORTHEAST OK AFTER 12Z.
LACY
PREV DISCUSSION... /ISSUED 625 PM CDT WED MAY 1 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL FOR THE EARLY PORTION OF THE TAF
PERIOD. A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT
WITH MVFR AND IFR CIGS BEHIND THE FRONT. SCATTERED SHOWERS AND
PERHAPS AN ISOLATED THUNDERSTORM WILL ALSO OCCUR BEHIND THE
FRONT...BUT THE CHANCE OF THUNDER IS TOO LOW TO INCLUDE AT THIS
TIME. GUSTY NW WINDS WILL PERSIST ONCE THE FRONT PASSES. AREAL
COVERAGE OF RAIN WILL INCREASE WITH TIME FROM WEST TO
EAST...HOWEVER,,,THE HIGHEST RAINFALL COVERAGE IS EXPECTED TO
REMAIN ACROSS ERN OK FOR MOST OF THE TAF PERIOD.
PREV DISCUSSION... /ISSUED 358 PM CDT WED MAY 1 2013/
DISCUSSION...
FOLKS...ENJOY THE REST OF TODAY BECAUSE ITS ABOUT TO GO SOUTH
IN A BIG HURRY. UNSEASONABLY STRONG COLD FRONT WHICH HAS BEEN
SHOWN IN LAST SEVERAL MODEL RUNS IS MOVING THROUGH WESTERN OK
THIS AFTERNOON WITH TEMPS FALLING IN LOW-MID 40S WITHIN SHORT TIME
OF FROPA. MOISTURE RETURN AHEAD OF THE FRONT HAS BEEN SUPPRESSED
FAIRLY WELL BY SUMMER LIKE LOW ALONG GULF COAST. THIS LOW HAS
MOVED FAR ENOUGH NORTH TO INFLUENCE WESTERN ARKANSAS WITH ISOLATED
AFTERNOON STORMS OVER HIGHER TERRAIN. NOT MUCH ALONG THE FRONT
YET BUT A FEW STORMS HAVE DEVELOPED OVER SW OK.
CAPPED ATMOSPHERE AND UPPER AIR SUPPORT LAGGING WELL BEHIND THE
FRONT WILL KEEP CHANCE OF SEVERE STORMS ALONG THE FRONT MINIMAL
THROUGH THE EVENING...PLUS ANY STORM THAT CAN GET GOING IN THE
WARM AIR WILL BE UNDERCUT QUICK. THE MAIN MESSAGE WITH THIS SYSTEM
IS THE MUCH COLDER TEMPERATURES...AND THE ALMOST UNTHINKABLE
CHANCE OF WINTER PRECIP BY THURSDAY NIGHT AND EARLY FRIDAY OVER
NORTHERN AREAS. MODELS REMAIN DIVERGENT WITH THE STRENGTH AND
TRACK OF UPPER LEVEL LOW...GFS FARTHER SOUTH AND OVERALL SCARIEST
IN TERMS OF SNOW POTENTIAL...NAM COLDEST BUT FASTER. UK/ECMWF ARE
THE MOST REASONABLE LOOKING AT THIS POINT AND HAVE BEEN FOLLOWED...
WITH A NOD TO THE LOCAL WRF FOR TEMP TRENDS ALONG AND WEST OF THE
FRONT TONIGHT.
PRECIP SHOULD BEGIN TO INCREASE LATER THURSDAY AND THU NIGHT AS
THE UPPER SYSTEM MOVES CLOSER...AND THIS AFFORDS US OUR SHOT AT
SNOW. GIVEN THE TIME OF YEAR...IT WILL TAKE A BURST OF HEAVY
SNOWFALL OVER A LONG ENOUGH PERIOD TO ACCUMULATE SNOW AS SFC TEMPS
LIKELY TO REMAIN JUST ABOVE FREEZING. STILL...IT WILL ONLY TAKE A
SMALL AMOUNT TO CAUSE SERIOUS ISSUES IN TERMS OF ACCUMULATING ON
TREES WITH LEAVES. CONFIDENCE NOT HIGH ENOUGH FOR ADVISORY AS A
DEGREE OR TWO WILL MAKE ALL THE DIFFERENCE...BUT A STRONGLY WORDED
SPS WILL BE ISSUED DUE MAINLY TO THE UNPRECEDENTED NATURE OF THIS
EVENT.
OVERALL TREND WILL BE FOR PRECIP TO DIMINISH DURING THE DAY FRIDAY
WITH RECORD LOW MAXES LIKELY AS TEMPS STRUGGLE TO REACH 50 DEGREES
IN AREAS WHERE PRECIP LINGERS LONG ENOUGH. COULD SEE A BIT OF WRAP
AROUND PRECIP MIX WITH SNOW OVER NW ARKANSAS FRIDAY NIGHT.
FREEZING TEMPS POSSIBLE THU NIGHT IN NE OK AND NW AR FRI NIGHT...
FREEZE WATCH ISSUED FOR NE OK THU NIGHT AND ONE MAY END UP BEING
NEEDED FOR NW ARKANSAS FRI NIGHT.
BEYOND THAT A RETURN TO MORE NORMAL SPRING WEATHER SHOULD OCCUR
WITH TEMPS CLOSER TO NORMAL BY EARLY NEXT WEEK. ANOTHER SYSTEM
COULD BRING SHOWERS AND THUNDERSTORMS TUE/WED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 42 43 34 49 / 60 70 90 40
FSM 62 64 38 50 / 20 70 90 40
MLC 47 48 35 51 / 30 60 90 20
BVO 40 41 33 49 / 70 80 90 50
FYV 53 53 35 46 / 20 70 100 50
BYV 54 55 37 44 / 20 70 100 60
MKO 47 48 35 50 / 40 60 100 40
MIO 44 45 34 47 / 60 80 100 60
F10 44 44 34 51 / 40 70 90 30
HHW 54 56 37 54 / 20 50 60 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FREEZE WATCH FROM 1 AM FRIDAY TO 10 AM FRIDAY FOR OKZ054-OKZ055-
OKZ056-OKZ057-OKZ059-OKZ060-OKZ061-OKZ064-OKZ065-OKZ066.
AR...NONE.
&&
$$
AVIATION...23
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
336 AM CDT THU MAY 2 2013
.TODAY...FORECAST CONFIDENCE...MEDIUM
MAIN ISSUE IS WHEN TO RAMP UP THE POPS. AS BOTTOM OF TROUGH CREATES
100 METER 500 MB 12 HOUR HEIGHT FALLS IN KS...MAIN BAROCLINIC ZONE
ONLY DRIFTS EAST DURING THE DAY.
CURRENT BAND OF PRECIPITATION IS SITUATED IN WARM ADVECTION AND
FRONTOGENESIS IN 700-600 MB LAYER. NOT MUCH PRECIPITATION FALLING
OUTSIDE OF THAT ZONE...WITH EXCEPTION OF A COUPLE OF SHOWERS AND
THUNDERSTORMS IN MISSOURI. SOME OF THE MODEL GUIDANCE WAY OVERDONE
ON QPF OVERNIGHT FROM MISSOURI INTO MICHIGAN. GFS IS WORST
OFFENDER.
PRECIPITATION CHANCES TODAY ARE MAINLY TIED TO CONVECTION FORMING IN
WEAK WARM ADVECTION ZONE TO EAST OF MAIN POST FRONTAL PRECIPITATION
SHIELD. IT WOULD FORM IN WARM SECTOR OVER ILLINOIS AND THEN BECOME
ELEVATED OVER SHALLOW LOW LEVEL COLD AIR IN SOUTHERN WISCONSIN.
MOST OF THE GUIDANCE PRODUCES CONVECTION INCLUDING THE 4KM NMM AND
ARW CORES. HOWEVER...THE COVERAGE MAY NOT BE SUFFICIENT TO WARRANT
CATEGORICAL POPS. LATEST HRRR MODEL HAS NOTHING HAPPENING THROUGH
20Z...BUT THERE ARE A FEW SHOWERS FROM 15-18Z ON LOCAL WSWRF 4KM ARW
CORE. WILL TRY AND KEEP POPS HIGH THIS AFTERNOON FOR NOW...BUT MAY
HAVE TO CONSIDER CHOPPING THEM DOWN A BIT AT 12Z SHORT TERM UPDATE
BEFORE HEADING HOME.
CLOUDS AND NORTHEAST WINDS WILL MAKE IT FEEL MUCH DIFFERENT TODAY
THAN PAST COUPLE OF DAYS. 40S MUCH OF THE DAY NEAR THE
LAKE...BASICALLY CUTTING THE TEMPERATURE IN HALF FROM PAST COUPLE OF
DAYS.
.TONIGHT...FORECAST CONFIDENCE...MEDIUM
CLOSED LOW BECOMES ESTABLISHED OVER KANSAS WITH FLOW GOING FROM
SOUTHWEST TO SOUTHERLY ALOFT OVER WISCONSIN. GRADUAL 40 METER
HEIGHT FALLS OVERNIGHT. MOST OF THE MODELS HAVE LIGHT PRECIPITATION
DURING THE NIGHT IN WEAK WARM ADVECTION REGIME. STRONGEST FORCING
SHOWN TO STAY CLOSER TO UPPER LOW FROM IOWA INTO MISSOURI.
BOTH NAM AND GFS SHOW SURFACE TEMPERATURES FALLING CLOSE TO FREEZING
IN FAR NORTHWEST AT SURFACE...BUT THAT AIR IS PRETTY SHALLOW. THERE
IS A NON-ZERO PROBABILITY OF FREEZING RAIN OUT WEST...BUT SREF
PROBABILITIES OF 60 TO 80% SEEM WAY TOO HIGH. LOOKS LIKE
TEMPERATURES GET DOWN TO 33 TO 35F WITH RAIN AND DEW POINTS AROUND
FREEZING...SO LITTLE HELP FROM WET BULB COOLING. FOR NOW WILL LEAVE
IT OUT.
.FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE...MEDIUM
WILL BE EVEN COOLER FRIDAY...WITH SHOWERS EXPECTED ACROSS THE
FORECAST AREA AS LOW PRESSURE TO THE SOUTHWEST DRIFTS EASTWARD.
EAST WINDS WILL LIKELY KEEP TEMPS IN THE 40S NEAR THE LAKE...WITH
HIGHS STRUGGLING TO AROUND 50 ELSEWHERE.
SHOWER CHANCES WILL CONTINUE SATURDAY AS THE LOW REMAINS IN THE
REGION...THE BEST CHANCE IN THE SOUTHWEST. LOOKS LIKE SOME MILDER
TEMPS MAY SNEAK BACK INTO THE AREA...WITH HIGHS EXPECTED TO
RECOVER TO AROUND NORMAL MOST PLACES. WILL LIKELY SEE COOLER TEMPS
NEAR THE LAKE UNDER ONSHORE WINDS.
SHOULD BE MAINLY DRY SUNDAY...BUT KEPT SOME LOW POPS IN AS THE LOW
CONTINUES TO SLOWLY PULL AWAY. NEAR AVERAGE TEMPS SHOULD CONTINUE.
.MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
UPPER LOW WILL FINALLY BE OUT OF THE AREA BY MONDAY...WITH MODELS
TRENDING DRIER FOR EARLY NEXT WEEK. THERE IS INCREASING AGREEMENT
THAT HIGH PRESSURE MAY BRING PLEASANT WEATHER THROUGH AT LEAST
TUESDAY...SO LOWERED POPS ACCORDINGLY. MAY BE ABLE TO GET RID OF
THE POPS ALTOGETHER SOON IF THIS TREND CONTINUES. SHOULD SEE
WARMING TEMPS...POSSIBLY HITTING THE 70 DEGREE MARK BY TUESDAY.
&&
.AVIATION/12Z TAFS/...
MAIN UNCERTAINTY IS WHEN PRECIPITATION WILL ARRIVE AND WHEN WILL IFR
CEILINGS FINALLY DEVELOP.
VFR CEILINGS SHOULD GRADUALLY LOWER AS CLOUDS INCREASE TODAY. MANY
OF THE MODELS DEVELOP CONVECTIVE SHOWERS OVER ILLINOIS IN THE WARM
SECTOR AND THEN MOVE THEM NORTH INTO WISCONSIN DURING THE
AFTERNOON. RAIN IS THEN SHOWN TO GROW IN COVERAGE DURING THE
EVENING. COMBINED WITH DIURNAL COOLING...STRATUS FORMATION SHOULD
COMMENCE WITH IFR TO PERHAPS LIFR CEILINGS.
CURRENT GUSTY NORTHEAST SHOULD RELAX A BIT BUT STILL DECENT CHANCE
OF 20-25 KNOT GUSTS TODAY AND TONIGHT.
&&
.MARINE...
WINDS GUSTED TO NEAR GALE FORCE FOR A TIME BUT SHOULD SETTLE INTO
STEADY SMALL CRAFT ADVISORY LEVELS FROM NNE AND CONTINUE THROUGH
FRIDAY. FAVORABLE FETCH AND SLOW PROCESS OF SUBSIDING WAVES MAY
REQUIRE SCA TO BE EXTENDED INTO FRIDAY EVENING BUT PLENTY OF TIME TO
EVALUATE THAT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT FRIDAY FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...CRAVEN
FRIDAY THROUGH WEDNESDAY...DDV
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
659 AM CDT THU MAY 2 2013
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1038 PM CDT WED MAY 1 2013
THE 02.00Z 250 HPA RAOB MAP SHOWED STRONG FLOW ACROSS THE ROCKIES AND
ACROSS THE NORTHERN PLAINS ASSOCIATED WITH A LARGE SCALE TROF. MAGNITUDES
WERE AROUND 100 KT. STRONGER FLOW OF 130 KT WAS NOTED ACROSS WESTERN
ONTARIO. AT 500 HPA, A VERY IMPRESSIVE FOR 02 MAY COLD POOL OF -30 DEG
C TO -33 DEG C WAS NOTED ACROSS MONTANA AND WYOMING. THIS WAS ASSOCIATED
WITH THE AFOREMENTIONED TROF. AT 700 HPA, AN IMPRESSIVE TEMPERATURE
GRADIENT BETWEEN KDDC (+3 DEG C) AND KLBF (-8 DEG C) WAS NOTED. FARTHER
UPSTREAM, MID LEVEL TEMPERATURES WERE EVEN COLDER WITH -15 DEG C AT
KGGW AT -18 DEG C AT CYQD. AT 850 HPA, THE AMOUNT OF COLD AIR ADVECTION
BETWEEN 00Z SYNOPTIC FLIGHTS WAS TREMENDOUS (25 DEG C TO -3 DEG C AT
KDDC). IN FACT, THE OBSERVED VALUE OF -2.8 DEG C IS WELL BELOW 2 STANDARD
DEVIATIONS AND CLOSER TO THE MINIMUM OF -5 DEG C FOR 850 HPA STATISTICS.
THIS IS OBVIOUSLY AT THE TAIL END OF EXTREMES FOR A GAUSSIAN DISTRIBUTION.
AT THE SURFACE, A STRONG COLD FRONT HAD PUSHED WELL SOUTH OF THE REGION.
A 1038 HPA ANTICYCLONE WAS BUILDING IN THE WAKE OF THE FRONT ACROSS
THE HIGH PLAINS. WSR-88D RADAR MOSAIC SHOWED SNOW ACROSS NW KANSAS AND
CONVECTION ACROSS SC KANSAS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT THU MAY 2 2013
BUSY MORNING WITH NUMEROUS SENSIBLE WEATHER IMPACTS AND RESULTANT
GRID MODIFICATIONS.
THIS MORNING:
KDDC WSR-88D REFLECTIVITY AND SURFACE OBSERVATIONS CONTINUE TO INDICATE
A BAND OF SNOW MOVING ACROSS WESTERN KANSAS EARLY THIS MORNING. A QUICK
LOOK AT KDOT CAMERAS DO SHOW THAT SOME OF THE SNOW IS STICKING TO THE
ROADWAYS ACROSS THE INTERSTATE 70 CORRIDOR. AFTER CHECKING NAM/WRF/RAP/AND
HRRR MODELS, IT APPEARS THAT THE HRRR IS DOING THE BETTER JOB WITH SNOW
FORECASTS COMPARED WITH ACTUAL LSR`S UPSTREAM. AS A RESULT, HEAVILY
BIASED THE NEAR TERM FORECAST TO HRRR OUTPUT SOLUTIONS. THE SNOW IS
IN ASSOCIATION WITH A TIGHT 700 HPA BAROCLINIC AS WELL AS THE PASSAGE
AND RESULTANT SYNOPTIC FORCING OF A 250 HPA JET STREAK (RIGHT ENTRANCE
REGION). HAVE ISSUED A WINTER WEATHER ADVISORY FOR NW/N PORTIONS OF
THE FORECAST AREA OF RESPONSIBILITY. MOST ACCUMULATION SHOULD BE ON
GRASSY/ELEVATED SURFACES, BUT IT WOULD NOT TAKE MUCH TO GET TEMPORARY
HAZARDOUS TRAVEL CONDITIONS. THIS IS TRULY AN IMPRESSIVE EVENT WITH
CURRENT OBSERVATIONS. FOR OTHER RELATED INFORMATION, SEE THE SYNOPSIS
AND WSW.
ELSEWHERE, MINIMUM TEMPERATURES FOR THIS MORNING APPEAR TO BE ON TRACK
AND WILL CONTINUE THE FREEZE WARNING AS IS.
TODAY:
TODAY WILL BE COLD WITH MAXIMUM TEMPERATURES IN THE 40S. STRATUS WILL
STICK AROUND FOR THE FIRST HALF OF TODAY SO TEMPERATURES WILL NOT GET
THE CHANCE TO CLIMB. THE COLDEST TEMPERATURES ARE FORECAST ACROSS SC
KANSAS WHERE CLOUDS AND PRECIPITATION WILL RESIDE LONGER. THE OTHER
CONCERN FOR TODAY IS WINDS. 850 HPA WINDS AROUND 50 KT AND A TIGHT PRESSURE
GRADIENT DO SPELL OUT THE CONCERN FOR A WIND ADVISORY GENERALLY SOUTH
OF THE ARKANSAS RIVER. HAVE ISSUED AS A RESULT WITH THE NAM SHOWING
WIND ADVISORY CRITERIA FOR THE SOUTHERN ROW OF COUNTIES EXCEPT MORTON
COUNTY.
TONIGHT:
THE MAIN SYNOPTIC WAVE WILL BE EAST OF THE REGION BY LATE TONIGHT. SUBSIDENCE
AND DRY AIR ADVECTION IS EXPECTED IN THE WAKE OF THE TROF. HIGH PRESSURE
WILL BUILD AT THE SURFACE WITH WINDS BECOMING LIGHT. HAVE UPGRADED THE
TWO WATCHES TO WARNINGS WITH A HARD FREEZE WARNING COVERING MUCH OF
THE FORECAST AREA OF RESPONSIBILITY EXCEPT ACROSS PORTIONS OF SC KANSAS
WHERE MINIMUMS WILL BE SLIGHTLY MORE "MILD". STILL, WE ARE LOOKING AT
VERY COLD LOWS WITH MINIMUMS MAINLY IN THE 20S DEG F.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 356 AM CDT THU MAY 2 2013
BY FRIDAY MORNING, THE DEEP UPPER TROUGH OVER THE NORTHERN AND
CENTRAL PLAINS WILL BE CLOSING OFF INTO AN UPPER LOW CENTERED ALONG
THE BORDER OF SOUTHEAST KANSAS AND NORTHEAST OKLAHOMA. FROM THERE,
THE MEDIUM RANGE MODELS MOVE THE LOW EAST ALONG THE BORDER OF
MISSOURI AND ARKANSAS THROUGH SATURDAY. THE MODELS ARE SHOWING A
LOBE OF VORTICITY ROTATING AROUND THE NORTH SIDE OF THE UPPER LOW
AND BACK INTO CENTRAL AND PARTS OF WESTERN KANSAS ON SATURDAY. THE
NAM AND GFS ARE SHOWING SOME LIGHT PRECIPITATION SPREADING INTO
CENTRAL AND PARTS OF WESTERN KANSAS DURING THE DAY SATURDAY AS WELL.
THE UKMET ALSO SHOWS THIS WHILE THE ECMWF AND GEM ARE NOT AS
AGGRESSIVE. IN COLLABORATION WITH SURROUNDING OFFICES, HAVE BUMPED
UP POPS FOR LIGHT RAIN SOMEWHAT DURING THE DAY SATURDAY WITH POPS
TAPERING OFF BY SATURDAY EVENING.
WE SHOULD HAVE A FEW DAYS OF DRY WEATHER DURING THE EARLY PART OF
NEXT WEEK AS THE CLOSED UPPER LOW CONTINUES TO MOVE INTO THE
SOUTHEASTERN STATES AND WEAK UPPER LEVEL RIDGING DOMINATES THE
CENTRAL PLAINS. THE MODELS TEND TO AGREE THAT ANOTHER UPPER LOW WILL
FORM OVER THE NORTHERN ROCKIES AND DIG SOUTHWESTWARD TO JUST OFF THE
CALIFORNIA COAST BY SUNDAY EVENING. AFTER THIS TIME THE MODELS
REALLY DIVERGE WITH HOW THIS SYSTEM EVOLVES AND MOVES EASTWARD
TOWARD THE PLAINS BUT ALL THE MODELS ARE MORE OR LESS SHOWING AN
INITIAL PIECE OF ENERGY EJECTING OUT TOWARD THE CENTRAL PLAINS AND
INCREASING CHANCES FOR SHOWERS ACROSS WESTERN KANSAS BY MONDAY NIGHT
AND TUESDAY. THE MAIN UPPER LOW OPENS UP SOMEWHAT AS IT MOVES OUT
OVER THE CENTRAL PLAINS THROUGH THE MIDDLE PART OF NEXT WEEK. THE
LATEST ALLBLEND HAS SLIGHT CHANCE OR CHANCE POPS THROUGH THE MIDDLE
PART OF NEXT WEEK. SUFFICE IT TO SAY THAT IT IS DIFFICULT TO NARROW
DOWN ANY SPECIFIC DAYS THAT PRECIPITATION CHANCES WILL BE THE BEST
DURING THAT TIME PERIOD GIVEN THE MODEL DIFFERENCES SO WILL KEEP
CHANCES FOR PRECIPITATION IN THE FORECAST THROUGH THURSDAY BEFORE
CHANCES SHOULD BE DECREASING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 659 AM CDT THU MAY 2 2013
LIGHT SNOW WILL BE ENDING BY 14Z AT THE TAF SITES ACROSS SOUTHWEST
KANSAS. MVFR/IFR CIGS WILL BECOME VFR BY 15-17Z. NORTH WINDS WILL
CONTINUE GUSTY AT 15 TO 25 KNOTS BUT WILL DIMINISH FAIRLY QUICKLY
BY 00Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 46 27 56 34 / 50 0 10 10
GCK 47 26 58 33 / 30 0 0 10
EHA 46 27 60 36 / 30 0 0 0
LBL 46 25 59 35 / 50 0 0 0
HYS 47 27 52 34 / 40 0 10 20
P28 44 31 54 36 / 100 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM 11 PM CDT /10 PM MDT/ THIS EVENING TO 1
PM CDT /NOON MDT/ FRIDAY FOR KSZ030-031-043>046-061>065-074>078-
084>087.
WINTER WEATHER ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ030-
043>045.
FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
KSZ030-031-043>046-061>065-074>080-084>088.
FREEZE WARNING FROM 11 PM THIS EVENING TO 1 PM CDT FRIDAY FOR
KSZ066-079>081-088>090.
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ085>090.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...GERARD
AVIATION...GERARD
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
1018 AM EDT THU MAY 2 2013
.SYNOPSIS...
ISSUED AT 421 AM EDT THU MAY 2 2013
A STRONG LOW PRESSURE SYSTEM WILL TAKE SHAPE ACROSS THE CENTRAL
PLAINS AND MID MISSISSIPPI VALLEY THROUGH THE WEEKEND...AS UPPER
LEVEL HIGH PRESSURE REMAINS PARKED ACROSS THE GREAT LAKES AND
NORTHEAST STATES. THIS WEATHER PATTERN WILL YIELD CONTINUED MILD
TEMPERATURES RIGHT ON THROUGH THE WEEKEND...WITH JUST A FEW SMALL
CHANCES FOR MAINLY AFTERNOON RAIN SHOWERS. DRY BUT CONTINUED WARM
WEATHER IS EXPECTED FOR MUCH OF NEXT WEEK...AS HIGH PRESSURE REMAINS
IN CONTROL ACROSS THE GREAT LAKES.
&&
.UPDATE...
ISSUED AT 1018 AM EDT THU MAY 2 2013
CHANGES THIS HOUR: HAVE LOWERED HIGHS JUST A TAD AND DELAYED
SHOWER POTENTIAL TO PRIMARILY 18Z AND BEYOND. OTHERWISE...MINOR
CHANGES TO SKY TO ACCOUNT FOR STRATUS NEAR WHITEFISH POINT.
COOL FRONT SITS OVER THE CWA ATTM WITH 12Z APX RAOB SHOWING VERY
IMPRESSIVE...ALBEIT VERY SHALLOW SURFACE BASED INVERSION WITH T9
AT 19C AND +13C AT H8. BOUNDARY IS LIKELY TO MIX NORTH AND WEST
GIVEN AMPLE SURFACE BASED HEATING OVER NORTHERN LOWER HEADING INTO
EARLY AFTERNOON. SOME CAVEATS TO THIS...HOWEVER...INCLUDE
DEVELOPING MID CLOUDS FROM CAD TO CVX UNDER ISENTROPIC ASCENT AT
THIS LEVEL WHICH MAY HELP REINFORCE THE BOUNDARY IF IT CAN HOLD
TOGETHER. EXPECT THAT IT WILL NOT /OR MORE LIKELY THAT IT WILL
LIFT NORTH WITH TIME/...ALLOWING BOUNDARY TO PUSH TOWARDS THE
COAST OF NW LOWER. THIS SHOULD ALLOW TEMPS TO WORK TOWARDS
PREVIOUSLY FORECASTED HIGHS. CERTAINLY SOME TEMPERATURE BUST
POTENTIAL IN THE VICINITY OF WHERE THIS FRONT MIXES TO THIS
AFTERNOON /TVC-ACB-PLN/.
EARLY MORNING RAP SOUNDINGS HAVE A MUCH BETTER HANDLE ON MOISTURE
OVER ARRIVING AIRMASS FROM SOUTHEAST LOWER THAN THE NAM /12Z DTX
RAOB SHOWS 0C DEWPOINT AT H8...WITH 6C FROM THE NAM/. THE RESULT
OF THIS IS AN AFTERNOON CHARACTERIZED BY MORE MID 40S DEWPOINTS
THAN LOW 50S...REDUCING CONVECTIVE POTENTIAL. WILL THUS DELAY
POPS...BUT NOT PULL THEM AT THIS POINT...BUT AWAIT 12Z GUIDANCE
AND LATE MORNING OBSERVATIONAL TRENDS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 421 AM EDT THU MAY 2 2013
EARLY MORNING SURFACE ANALYSIS SHOWS A COLD/STATIONARY FRONT
EXTENDING FROM NORTHERN QUEBEC...SOUTHWEST ACROSS CENTRAL LOWER
MICHIGAN AND DOWN INTO NORTHWEST ILLINOIS/CENTRAL MISSOURI AND ON
INTO THE SOUTHERN PLAINS. THIS FRONT WAS ASSOCIATED WITH AN UPPER
LEVEL TROUGH ENCOMPASSING THE NATION`S MIDSECTION...AND ITS EASTWARD
PROGRESS WAS BEING IMPEDED BY A NARROW BUT HIGH AMPLITUDE BLOCKING
RIDGE OVER THE EASTERN THIRD OF THE NATION AND SUBSEQUENT TROUGHING
OVER THE WESTERN ATLANTIC. A 30-40 DEGREE TEMPERATURE CONTRAST
EXISTS ACROSS THE FRONT...WITH AN ELONGATED BAND OF POST-FRONTAL
RAIN AND SNOW FROM THE CENTRAL/SOUTHERN PLAINS NORTHWARD INTO THE
UPPER MISSISSIPPI VALLEY. CLOSER TO HOME...SCATTERED CONVECTION
DEVELOPED EARLIER ACROSS EASTERN UPPER MICHIGAN/NORTHERN LAKE
MICHIGAN...THE TAIL END OF A BAND OF SCATTERED SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHEAST ONTARIO. OTHERWISE SKIES ARE
CLEAR/PARTLY CLOUDY ACROSS NORTHERN LOWER.
STURDY RIDGE TO THE EAST WILL KEEP THINGS IN A HOLDING PATTERN
TODAY...STATIONARY FRONT WILL LIKELY WAVER A BIT DUE TO MIXING AND
LAKE BREEZE EFFECTS...BUT IS GOING TO ESSENTIALLY BISECT LOWER
MICHIGAN FROM NORTH TO SOUTH THROUGH THE SHORT TERM PERIOD. THIS
PRODUCES A MYRIAD OF FORECAST ISSUES FOR TODAY AND TONIGHT WITH
REGARD TO PRECIP CHANCES...TEMPERATURES...AND WINDS.
PRECIP ISSUES TODAY ARE PROBABLY GOING TO BE SIMILAR TO THOSE OF
WEDNESDAY...THAT IS WILL THERE BE ENOUGH MOISTURE TO GENERATE
INSTABILITY ALONG THE FRONT. FIRST...EXPECT THE FRONT TO MIX BACK
TO THE WEST...PROBABLY BACK TOWARD GLR-GOV-CAD THOUGH NORTHERN END
OF THE FRONT WILL PROBABLY BE DEFORMED IN AN EAST-WEST DIRECTION AS
LAKE HURON BREEZE RAMPS UP. THERE ARE INDICATIONS IN THE FORECAST
SOUNDINGS...PARTICULARLY THE GFS...OF STRATUS DEVELOPING ON THE COOL
SIDE OF THE FRONT VERY SHORTLY. THERE AREN`T ANY INDICATIONS OF
SUCH AS YET...SO WILL START OUT BY DOWNPLAYING THIS IDEA INITIALLY.
CAN SEE THE POSSIBILITY OF LOW CLOUDS DEVELOPING LATER THIS MORNING
AS THERMAL CONTRAST TIGHTENS...SUCH A SCENARIO IS MORE LIKELY OVER
THE COLD WATERS OF LAKE MICHIGAN AND PERHAPS SPILLING INTO ADJACENT
LAKESHORE AREAS OF NORTHWEST LOWER. SO WITH THE FRONT BACKING
TOWARD NORTHWEST LOWER...WILL PROBABLY TAKE DEW POINTS REMAINING IN
THE LOWER 50S TO GENERATE AROUND 500J/KG MLCAPE. TOOK ALL AFTERNOON
YESTERDAY TO GENERATE ONE SHOWER DURING THE EARLY EVENING...WONDER
IF WE`LL BE FACING THE SAME ISSUE TODAY. CURRENT THINKING IS THAT
IT IS CLOSE ENOUGH TO JUSTIFY CHANCE AFTERNOON POPS ACROSS MUCH OF
INTERIOR NORTHERN LOWER. ANOTHER POSSIBILITY FOR NORTHWEST LOWER IS
THAT UNSTABLE WARM SECTOR PARCELS ARE PULLED UP THE FRONTAL ZONE AND
CONVECT ON THE COOL SIDE OF THE BOUNDARY (ALONG/WEST OF US-131
CORRIDOR). SO SEVERAL POSSIBILITIES HERE. AS FOR TEMPERATURES
TODAY...AGAIN WILL VARY WIDELY DEPENDING ON LOCATION RELATIVE TO THE
FRONT AND LAKE BREEZE ACTIVITY. DON`T SEE WHY TEMPERATURES ON THE
WARM SIDE OF THE BOUNDARY WON`T MAKE ANOTHER RUN AT 80+ TODAY AS
CLOUD COVER SHOULD NOT BE MUCH OF AN ISSUE. RECORD HIGHS ARE A BIT
WARMER THAN YESTERDAY (APN 86/2001...HTL 88/1959...GLR 85/1959)...
AND WILL TAKE SOME TIME TO MIX THROUGH THE FRONTAL INVERSION SO
SHOULD BE A LITTLE SLOWER TEMPERATURE CLIMB THIS MORNING.
FOR TONIGHT...WILL BE DEALING BOTH WITH DEEPER MOISTURE NUDGING INTO
WESTERN PORTIONS OF THE FORECAST AREA AS WELL AS ELEVATED
INSTABILITY AND CONTINUE WARM ADVECTION. MUCH OF THE MOISTURE WILL
BE ACROSS THE WESTERN HALF OF THE FORECAST AREA AND THUS HIGHER
POPS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EDT THU MAY 2 2013
SPRING LOOKS LIKE IT`S HERE TO STAY FOR THE FORESEEABLE FUTURE...
WITH ACTUALLY VERY FEW FORECAST ISSUES NOTED THROUGH THE WEEKEND AND
MAJORITY OF NEXT WORK WEEK. OVERALL UPPER PATTERN IS PROGGED BY ALL
AVAILABLE MEDIUM RANGE GUIDANCE TO REMAIN HEAVILY BLOCKED UP AS
CLOSED LOW DEVELOPMENT TAKES PLACE OVER THE MID MISSISSIPPI
VALLEY...WHILE ANOTHER CLOSED LOW MEANDER OVER THE WESTERN
ATLANTIC...EFFECTIVELY PINNING A RATHER EXPANSIVE OMEGA-TYPE RIDGE
IN PLACE FROM FLORIDA RIGHT ON UP THROUGH THE GREAT LAKES AND MUCH
OF EASTERN CANADA. THAT RIDGE SHOULD INCREASINGLY BECOME CUT OFF
OVER THE NORTHERN TIER FOR THE FIRST PART OF NEXT WEEK...AS THE
CLOSED LOW WANDERS RATHER AIMLESSLY SOMEWHERE TO OUR SOUTH (EXACT
POSITION STILL TO BE DETERMINED). AS THAT OCCURS...PREVAILING SOUTH
TO SOUTHEASTERLY LOW LEVEL FLOW WILL CONTINUE TO TRANSPORT SOME
RATHER MILD AIR NORTHWARD AS A PERSISTENT THERMAL RIDGE FEATURE
HOLDS INTACT ACROSS THE GREAT LAKES...FAVORING SOME MORE MUCH NEEDED
(AND LET`S FACE IT...MUCH DESERVED) WARM SPRINGTIME WEATHER FOR THE
NORTH WOODS.
LOOKING AT SOME SPECIFICS...STALLED FRONTAL BOUNDARY/INVERTED
TROUGH AXIS REMAINS PROGGED TO RESIDE ACROSS THE AREA THROUGH
FRIDAY...EFFECTIVELY SPLITTING THE STATE IN HALF. GIVEN YESTERDAY`S
HISTORY WITH THIS BOUNDARY COUPLED WITH AN INCREASINGLY DRIER
BOUNDARY LAYER LIKELY TO BE SHUNTED INTO THE REGION ON SLOWLY
BACKING SOUTHEAST FLOW REGIME...HAVE SOME DIFFICULTY BELIEVING WE
WILL BE ABLE TO MUSTER MUCH IN THE WAY OF ANY AFTERNOON CONVECTION.
WITH THAT SAID...THE CHANCE IS NOT COMPLETELY ZERO WITH A LIGHT
WIND/LAKE BREEZE REGIME FAVORING ENHANCED CONVERGENCE INTO THE
SLUGGISH SYNOPTIC BOUNDARY...AND AT LEAST DECENT HEATING ACROSS
NORTHEAST LOWER AND THE HIGHER TERRAIN.
THEREAFTER...JUST CANNOT JUSTIFY HAVING ANY POPS IN THE FORECAST
BEYOND FRIDAY EVENING...AS THE ENTIRE PATTERN SLOWLY RETROGRADES AND
THE BEST MOISTURE AXIS SLIPS WELL TO OUR WEST...ALL WHILE AN
INCREASINGLY DRY BOUNDARY LAYER MAKES AN APPEARANCE THROUGH THE
WEEKEND. LOOKING INTO NEXT WEEK...DEEPER MOISTURE AXIS SHOULD REMAIN
WELL TO OUR SOUTH AS THE UPPER LOW PINWHEELS THROUGH THE TENNESSEE
VALLEY (OR SOMEWHERE NEAR THERE)...WITH DRY EASTERLY FLOW PREVAILING
UP THIS WAY AND SUBSIDENCE ON THE NORTHERN FRINGE OF CLOSED LOW
FEATURE FAVORING LOTS OF SUNSHINE. HIGHS SHOULD RESPOND NICELY INTO
THE 60S TO MIDDLE 70S EACH AFTERNOON...COOLER NEAR THE LAKESHORES OF
COURSE WHERE LAKE BREEZE DEVELOPMENT IS LIKELY EACH DAY GIVEN A VERY
WEAK GRADIENT IN PLACE. OVERNIGHT LOWS ARE A BIT MORE TRICKY IN THIS
LIGHT GRADIENT SETUP...AS DAILY MIXING OF DEW POINTS INTO THE 40S
AND MAYBE 30S AND CLEAR SKIES SHOULD EASILY ALLOW READINGS TO DIP
QUICKLY AFTER SUNSET. SIMPLY PUT...THE WEATHER THROUGH NEXT WEEK
LOOKS DOWNRIGHT SPECTACULAR FOR ALL OF NORTHERN MICHIGAN...WITH WARM
SUNNY DAYS AND COOL COMFORTABLE NIGHTS. ENJOY!
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1250 AM EDT THU MAY 2 2013
VFR. -SHRA POSSIBLE TO LIKELY THURSDAY AFTERNOON/EVENING MBL/TVC/PLN.
STALLING FRONT A BIT SE OF APN/HTL TONIGHT. SOME MID CLOUDS HAVE
DEVELOPED BEHIND THE FRONT (CIGS 6-10K FT). THIS DECK WILL BE
SOMEWHAT SPORADIC UNTIL THU AFTERNOON...WHEN CLOUDS WILL THICKEN
(ESPECIALLY IN NW LOWER AND THE STRAITS REGION). SOME -SHRA WILL
DEVELOP FROM THIS DECK IN THE AFTERNOON AND EVENING. MBL/TVC/PLN ALL
HAVE SOME MIX OF -SHRA AND/OR VCSH IN THE TAF IN THE AFTERNOON/
EVENING. WILL KEEP CONDITIONS VFR FOR NOW...THOUGH ANY PLACE THAT
GETS DECENTLY WET LATE THURSDAY WILL BE AT AN ENHANCED RISK TO SEE
FOG/STRATUS FORM THURSDAY NIGHT.
NORTHERLY BREEZES WILL CONTINUE AT MBL/TVC/PLN...WITH AN EAST WIND
FOR MOST OF THE FORECAST AT APN.
&&
.MARINE...
ISSUED AT 421 AM EDT THU MAY 2 2013
STATIONARY FRONT BISECTING LOWER MICHIGAN FROM NORTH TO SOUTH WILL
PRODUCE VERY DIFFERENT WIND CONDITIONS BETWEEN WHITEFISH BAY/LAKE
MICHIGAN AND LAKE HURON NEARSHORE ZONES...EVEN ON LAKE HURON
CONDITIONS WILL VARY QUITE A BIT. WESTERN ZONES WILL BE DEALING
WITH A STRONGER NORTHERLY GRADIENT ON THE COOLER SIDE OF THE
BOUNDARY...MAY PUSH SMALL CRAFT CONDITIONS WITHIN NORTHWEST LOWER
NEARSHORE ZONES. ON LAKE HURON...WINDS WILL VARY FROM A NORTHERLY
COMPONENT NORTH OF THUNDER BAY...AND A SOUTHERLY COMPONENT SOUTH
THOUGH BOTH AREAS WILL BE IMPACTED LOCALLY BY LAKE BREEZE COMPONENTS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ323-
344>346.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...DL
SHORT TERM...JPB
LONG TERM...DL
AVIATION...JZ
MARINE...JPB
AREA FORECAST DISCUSSION
NWS BUFFALO NY
959 AM EDT THU MAY 2 2013
.SYNOPSIS...
HIGH PRESSURE IN PLACE ACROSS THE EASTERN STATES WILL REMAIN IN
CONTROL OF OUR WEATHER FOR THE REST OF THE WEEK. THIS WILL
PROVIDE US WITH PLENTY OF SUNSHINE AND WELL ABOVE AVERAGE
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL REMAIN IN CONTROL
OF OUR WEATHER THROUGH TONIGHT. ANOTHER SUNNY DAY TODAY WITH WARM AFTERNOON
TEMPERATURES IN THE MID 70S TO ABOUT 80...ALTHOUGH LAKESHORE AREAS
WILL BACK OFF FROM THESE NUMBERS ONCE THE LAKE BREEZES KICK IN.
UPDATED FORECAST GRIDS THIS MORNING WITH LATEST HRRR MODEL TEMPS
AND WINDS TO ACCOUNT FOR THE SHIFTING WINDS AND COOLING TEMPS ALONG
THE LAKE SHORES ONCE THE LAKE BREEZE SETS UP. THE LAKE BREEZE LOOKS
TO WORK INLAND ACROSS MOST OF ALL LAKE BORDERING COUNTIES BY LATE
AFTERNOON.
MODEL SUGGESTION OF SOME MID LEVEL MOISTURE ASSOCIATED WITH A SLIGHT
COOL DOWN ALOFT WILL PUSH THROUGH THE REGION FROM THE NORTHEAST
TONIGHT. AIR MASS TOO DRY FOR ANYTHING MORE THAN A PERIOD OF MID AND
HIGH LEVEL CLOUDS WITH THIS FEATURE. MILD TEMPS EXPECTED AGAIN
TONIGHT ONLY FALLING INTO THE UPPER 40S TO LOW 50S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
SURFACE HIGH PRESSURE COVERING MUCH OF THE EASTERN U.S. WILL BE
OVERLAIN BY A DEVELOPING OMEGA BLOCK. AN UPPER RIDGE WILL BE
CENTERED BETWEEN A CUTOFF LOW OVER THE CENTRAL PLAINS AND ANOTHER
CUTOFF LOW ACROSS THE WESTERN ATLANTIC.
850MB TEMPERATURES ACROSS THE REGION WILL RANGE FROM AROUND +8C ON
FRIDAY TO +6C SATURDAY WITH UPPER 60S TO THE LOWER 70S...AND SOUTH
TO SOUTHEAST WINDS WILL HELP BOOST THE HIGH TEMPS TO THE MID 70S
ACROSS THE LAKE PLAINS AND VALLEYS.
LOW TEMPERATURES WILL ALSO BE MILD THROUGH THE PERIOD...WITH LOWS IN
THE LOWER 50S ON THE LAKE PLAINS OF WESTERN NY...WITH 40S ACROSS THE
HIGHER TERRAIN AND SOME SPOTS EAST OF LAKE ONTARIO.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE EXCEPTIONAL PERIOD OF DRY AND WARM WEATHER WILL LAST AT LEAST
THROUGH THE WEEKEND AS AN OMEGA BLOCK REMAINS IN PLACE ACROSS THE
EASTERN STATES WITH HIGH PRESSURE SURFACE AND ALOFT. 850MB TEMPS
REMAIN AROUND +8C OR BETTER INTO THE WEEKEND...SUPPORTING HIGHS IN
THE MID 70S ACROSS LOWER ELEVATIONS. THERE MAY BE A LITTLE CLOUD
COVER AT TIMES AS A FEW WEAK BACKDOOR FRONTS WASH OUT ON THE
NORTHERN PERIPHERY OF THE RIDGE...BUT STILL EXPECT A DECENT AMOUNT
OF SUN AS WELL.
THE FORECAST BECOMES MUCH MORE UNCERTAIN EARLY NEXT WEEK AS MODEL
GUIDANCE DIVERGES WITH THE HANDLING OF A MIDWEST CUTOFF LOW.
GUIDANCE HAS BEEN ALL OVER THE PLACE WITH THIS...AND IT IS NOT
UNUSUAL FOR GUIDANCE TO STRUGGLE WITH CUTOFF LOWS. BECAUSE OF THIS
SPREAD IN GUIDANCE...WILL AVOID FOCUSING ON ANY ONE MODEL OR RUN.
KEEPING THIS IN MIND...THE MAJORITY OF GUIDANCE KEEPS OUR AREA DRY
EARLY NEXT WEEK...WITH ONLY A MARGINAL CHANCE FOR SHOWERS AND COOLER
TEMPERATURES. CHANCES GRADUALLY INCREASE TOWARD MID-WEEK BUT STILL
ARE QUITE LOW. THE 00Z EUROPEAN SHOWED A SIGNIFICANT COLD FRONT
CROSSING ON WEDNESDAY...BUT THE MAJORITY OF OTHER GUIDANCE (06/12Z
GFS AND THE 12Z EURO) CONTINUE TO SHOW A BROAD RIDGE IN THE
EAST...WITH THE CUT-OFF LOW STILL LINGERING IN THE AREA.
TEMPERATURES SHOULD REMAIN ABOVE NORMAL THROUGH WEDNESDAY...AND THE
WARM WEATHER COULD EVEN LAST LONGER IF THE MAJORITY OF THE LONG
RANGE GUIDANCE IS CORRECT.
ENJOY.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL CONTINUE TO BRING VFR CONDITIONS TO THE FORECAST
AREA THROUGH AT LEAST TONIGHT. MAINLY SKC CONDITIONS TODAY WILL
GIVE WAY TO SOME MID LEVEL CLOUDS TONIGHT...MAINLY IMPACTING THE
KART AND KROC TERMINALS. LIGHT SOUTHEASTERLY WINDS WILL GIVE WAY TO
THE USUAL LAKE BREEZES THIS AFTERNOON WITH ALL TAFS BUT KJHW SEEING
WINDS SHIFT FROM THE LAKE TODAY THEN RETURN BACK SO SOUTHEASTERLY
AFTER LATER THIS EVENING.
OUTLOOK...
FRIDAY THROUGH MONDAY...VFR.
&&
.MARINE...
HIGH PRESSURE DOMINATING THE NORTHEASTERN UNITED STATES WILL PERSIST
THROUGH THE WEEKEND WITH LIGHT SOUTHEASTERLY FLOW RESULTING IN
TRANQUIL CONDITIONS ON THE LAKES. LAKE BREEZES WILL SET UP IN THE
EACH AFTERNOON.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...SMITH
SHORT TERM...WCH
LONG TERM...APFFEL
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
956 AM EDT THU MAY 2 2013
.DISCUSSION...
12Z RAOBS ACROSS THE REGION LOOK QUITE STABLE...AND FORECAST
SOUNDINGS FROM THE RUC INDICATE THAT STABLE CONDITIONS WILL
CONTINUE THROUGH THE DAY. A FEW ISOLATED SHOWERS COULD PRODUCE SOME
TRACE AMOUNTS IN SOUTHERN AREAS WHERE MOISTURE DEPTH IS
GREATEST...BUT WITH A LACK OF LIFT...THERE IS NO COMPELLING REASON
TO CHANGE THE CURRENT DRY FORECAST. TEMPS APPEAR TO BE ON
TRACK...SO NO UPDATE IS PLANNED.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1211 AM CDT THU MAY 2 2013
.DISCUSSION...
LOOK FOR CHALLENGING FLIGHT WEATHER CONDITIONS TO CONTINUE ACROSS
WEST CENTRAL TEXAS FOR THE REMAINDER OF TONIGHT AND MUCH OF
TOMORROW. PLEASE SEE AVIATION BELOW FOR DETAILS.
&&
.AVIATION...
MODELS THIS FORECAST CYCLE CONTINUE TO PRESENT A PICTURE FOR WEST
CENTRAL TEXAS WHICH INCLUDES MVFR CEILINGS AND VERY GUSTY NORTH
SURFACE WINDS FOR MUCH OF THE NEXT 24 HOURS. THE LATEST RUC AND
NAM CONTINUE THUNDERSTORMS ACROSS OUR HEARTLAND AND NORTHWEST
HILL COUNTRY COUNTIES FOR A FEW MORE HOURS. THEN...DRIZZLE OR
LIGHT SHOWERS WILL BE THE PRECIPITATION PRODUCERS OVER WEST
CENTRAL TEXAS UNTIL TOMORROW EVENING. THE UPPER-LEVEL THROUGH WILL
CONTINUE TO SLIDE OVER TEXAS INTO TOMORROW. AT THE SURFACE...COLD
AIR WILL CONTINUE TO MOVE INTO WEST CENTRAL TEXAS BEHIND THE
FRONT. SO...GUSTY NORTH SURFACE WINDS TOMORROW...ESPECIALLY DURING
THE AFTERNOON HOURS...CONTINUE TO LOOK LIKELY. WITH SOME
DISAGREEMENT AMONG THE MODELS...MY CONFIDENCE REGRADING WHEN VFR
CONDITIONS WILL RETURN TO WEST CENTRAL TEXAS IS NOT VERY HIGH.
THUS...I DECIDED TO CONTINUE MVFR CEILINGS AT ALL FIVE TERMINALS
UNTIL 18Z...WITH ONLY A PROB30 GROUP FROM 18Z UNTIL 00Z.
HUBER
&&
.PREV DISCUSSION... /ISSUED 1114 PM CDT WED MAY 1 2013/
UPDATE...
LATEST RADAR DATA INDICATE SHOWERS AND THUNDERSTORMS ARE SLOWLY
CLEARING OUR COUNTIES...AS THEY MOVE FARTHER SOUTHEAST. AFTER
COORDINATION WITH SPC...I HAVE CANCELED SEVERE THUNDERSTORM WATCH
146 FOR A FEW MORE OF OUR COUNTIES. I WILL ALLOW THE REMAINING
COUNTIES TO CONTINUE IN THIS WATCH UNTIL IT EXPIRES AT MIDNIGHT.
ALSO...I REMOVED THUNDERSTORMS FROM THE FORECAST FOR THE REMAINDER
OF TONIGHT FOR THOSE COUNTIES I REMOVED FROM THIS WATCH. RECENT
TEXT PRODUCTS REFLECT MY GRID UPDATES.
HUBER
PREV DISCUSSION... /ISSUED 1022 PM CDT WED MAY 1 2013/
UPDATE...
AFTER COORDINATION WITH SPC...I CLEARED SOME OF OUR NORTHWESTERN
COUNTIES FROM SEVERE THUNDERSTORM WATCH 146. THUNDERSTORMS ARE
CONTINUING TO MOVE SLOWLY SOUTHEAST WITH THE LEADING EDGE OF THE
COLD FRONT. TEMPERATURES AROUND 55 HAVE ALREADY MOVED INTO OUR
NORTHERN BIG COUNTRY COUNTIES...WHERE NORTH SURFACE WINDS AROUND
20 MPH DOMINATE. ALSO...I REMOVED THUNDERSTORMS FROM THOSE
COUNTIES I CLEARED FROM THE WATCH. RECENT TEXT PRODUCTS REFLECT
THESE GRID CHANGES.
HUBER
PREV DISCUSSION... /ISSUED 640 PM CDT WED MAY 1 2013/
DISCUSSION...
LOOK FOR VERY CHALLENGING FLIGHT WEATHER CONDITIONS ACROSS WEST
CENTRAL TEXAS FOR THE NEXT 24 HOURS. AVIATION BELOW HAS DETAILS.
AVIATION...
A STRONG COLD FRONT WILL PUSH SOUTH ACROSS WEST CENTRAL TEXAS
TONIGHT AND PRODUCE THUNDERSTORMS...ALONG WITH MVFR
CEILINGS...REDUCED VISIBILITY...A GUSTY NORTH WINDS. THE LATEST
RUC INDICATES THE LEADING EDGE OF THIS COLD FRONT WILL PUSH SOUTH
OF OUR INTERSTATE 10 CORRIDOR AROUND 08Z TONIGHT.
MEANWHILE...THUNDERSTORMS HAVE DEVELOPED...AND ARE
DEVELOPING...ALONG THE LEADING EDGE OF THIS FRONTAL BOUNDARY. SOME
OF THE THUNDERSTORMS MAY PRODUCE DAMAGING WINDS AND LARGE HAIL.
BEHIND THE FRONT...I EXPECT OVERCAST MVFR CEILINGS AND LIGHT RAIN
TO DOMINATE WEST CENTRAL TEXAS FOR THE REMAINDER OF THIS FORECAST
PERIOD. ALSO...WATCH FOR VERY STRONG WINDS TOMORROW...ESPECIALLY
DURING THE AFTERNOON...AS COLD AIR MOVES INTO TEXAS FROM THE NORTH.
HUBER
PREV DISCUSSION... /ISSUED 513 PM CDT WED MAY 1 2013/
UPDATE...
AFTER COORDINATION WITH THE STORM PREDICTION CENTER...WE HAVE
ISSUED SEVERE THUNDERSTORM WATCH 146 WHICH WILL REMAIN IN EFFECT
UNTIL MIDNIGHT TONIGHT. I HAVE SENT A ZONE UPDATE TO INCLUDE THE
WATCH HEADLINE. AT THIS TIME...WE ARE THINKING THE MAIN THREAT
WILL BE DAMAGING WINDS.
HUBER
PREV DISCUSSION... /ISSUED 342 PM CDT WED MAY 1 2013/
SHORT TERM...
THE COLD FRONT...WHICH IS MORE OF A WIND SHIFT IN SOUTHERN
AREAS...HAS MADE IT INTO THE LOWER TRANS PECOS AREA...AND INTO OUR
EXTREME WESTERN COUNTIES. A WEAK SFC MESOLOW OR HEAT LOW CAN BE SEEN
IN RADAR DATA IN THE NORTHERN CONCHO VALLEY. TEMPERATURES HAVE
SOARED INTO THE UPPER 90S ACROSS THE CONCHO VALLEY WITH UPPER 80S TO
LOWER 90S ACROSS THE REST OF THE FORECAST AREA.
THERE IS STILL THE POSSIBILITY OF SOME ISOLATED STORMS DEVELOPING
THIS EVENING ACROSS THE SOUTHERN CONCHO VALLEY/NORTHERN EDWARDS
PLATEAU. WHILE SHEAR ISN/T THAT STRONG ACROSS THE AREA...WITH CAPE
VALUES JUST EAST OF THESE AREAS NOW EXCEEDING 3000 J/KG AT THE
SURFACE...ANY STORMS THAT DO DEVELOP WOULD QUICKLY BECOME STRONG TO
SEVERE WITH LARGE HAIL AND DAMAGING WINDS BEING THE MAIN HAZARDS.
THE MAIN CAVEATS WITH THUNDERSTORMS IN OUR AREA IS THE LACK OF
STRONG UPPER LEVEL SUPPORT OR A WELL DEFINED SFC FOCUS.
OVERNIGHT...THE COLD FRONT WILL SURGE SOUTHWARD...AND ADDITIONAL
ELEVATED CONVECTION BEHIND THE FRONT IS POSSIBLE. WITH INSTABILITY
DECREASING OVERNIGHT...EXPECT LESS OF A CHANCE FOR SEVERE
THUNDERSTORMS...BUT THERE COULD STILL BE THUNDERSTORMS THAT PRODUCE
SOME SMALL HAIL AND GUSTY WINDS.
MUCH COLDER AIR WILL MOVE INTO THE AREA BEHIND THE COLD FRONT FOR
TOMORROW...AND WINDS WILL ALSO BE QUITE STRONG...LIKELY 20 TO 35 MPH
THROUGHOUT THE AREA WITH GUSTS APPROACHING 45 MPH AT TIMES. THIS
WILL BE DUE TO STRONG PRESSURE RISES ASSOCIATED WITH A 1040+ MB
SURFACE HIGH MOVING INTO THE AREA. THURSDAY WILL BE A COLD...
CLOUDY...WINDY DAY WITH SOME SCATTERED SHOWERS AT TIMES. A WIND
ADVISORY WILL BE IN EFFECT FROM EARLY TOMORROW MORNING THROUGH
TOMORROW EVENING.
LONG TERM...
THURSDAY NIGHT THROUGH FRIDAY NIGHT...COLD TEMPERATURES ARE EXPECTED
THURSDAY NIGHT AS STRONG SURFACE HIGH SETTLES IN ALONG WITH GOOD LOW
LEVEL COLD AIR ADVECTION. LOWS BY FRIDAY MORNING WILL BE IN THE 30S.
A FEW UPPER 20S ARE POSSIBLE IF WINDS CAN DECOUPLE...THAT MAY BE A
PROBLEM DUE TO THE WINDS STAYING UP. THE NAM MOS GUIDANCE HAS A LOW
OF 23 AT JUNCTION FRIDAY MORNING WHICH IS PRETTY AMAZING FOR MAY
3. WILL GO WITH A FREEZE WATCH FOR LATE THURSDAY NIGHT AND FRIDAY
MORNING ACROSS ALL OF WEST CENTRAL TEXAS. TEMPERATURES WILL
MODERATE SOME FRIDAY WITH HIGHS IN THE 60S. ANOTHER COLD NIGHT FOR
FRIDAY NIGHT WITH LOWS MAINLY IN THE 30S. FREEZING TEMPERATURES
ARE POSSIBLE SATURDAY MORNING MAINLY ACROSS THE HEARTLAND AND
NORTHWEST HILL COUNTRY AS WINDS WILL HAVE A BETTER CHANCE TO
DECOUPLE SETTING UP IDEAL RADIATIONAL COOLING. SEE CLIMATE
INFORMATION BELOW FOR SPECIFICS.
SATURDAY THROUGH WEDNESDAY...EXPECT A WARMING TREND THROUGH THE
PERIOD...WITH HIGHS IN THE 80S MONDAY THROUGH WEDNESDAY. THE GFS
MODEL IS INDICATING AN UPPER LEVEL TROF UNDERCUTTING A RIDGE OVER
THE PACIFIC NORTHWEST. SOME OF THIS ENERGY MAY MOVE INTO THE
SOUTHERN PLAINS AS A DRYLINE DEVELOPS TO OUR WEST BY MIDDLE OF NEXT
WEEK. FORECAST CONFIDENCE IS LOW AT THIS TIME AND ALL OF WEST CENTRAL
TEXAS IS CURRENTLY IN SEVERE OR GREATER DROUGHT CONDITIONS. KEEPING
THE FORECAST DRY FOR NOW.
CLIMATE...
RECORD LOWS POSSIBLE FRIDAY AND SATURDAY...
ABILENE MAY 3 - FORECAST LOW 34 (RECORD LOW 37 IN 2011)
MAY 4 - FORECAST LOW 37 (RECORD LOW 33 IN 1907)
ALL TIME LOW TEMPERATURE FOR MAY - 33
SAN ANGELO MAY 3 - FORECAST LOW 32 (RECORD LOW 37 IN 2011)
MAY 4 - FORECAST LOW 36 (RECORD LOW 39 IN 1945)
ALL TIME RECORD LOW FOR MAY - 35
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 39 46 34 62 37 / 50 30 5 0 0
SAN ANGELO 45 48 32 66 36 / 50 30 5 0 0
JUNCTION 51 53 30 68 33 / 50 40 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR
THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...
CONCHO...CROCKETT...FISHER...HASKELL...IRION...JONES...KIMBLE...
MASON...MCCULLOCH...MENARD...NOLAN...RUNNELS...SAN SABA...
SCHLEICHER...SHACKELFORD...STERLING...SUTTON...TAYLOR...
THROCKMORTON...TOM GREEN.
WIND ADVISORY FROM 4 AM TO 7 PM CDT THURSDAY FOR THE FOLLOWING
ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO...CROCKETT...
FISHER...HASKELL...IRION...JONES...KIMBLE...MASON...MCCULLOCH...
MENARD...NOLAN...RUNNELS...SAN SABA...SCHLEICHER...SHACKELFORD...
STERLING...SUTTON...TAYLOR...THROCKMORTON...TOM GREEN.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1207 AM CDT THU MAY 2 2013
.AVIATION...
BKN-OVC MVFR CLOUD DECKS HAVE DEVELOPED ACROSS KLBB AND KCDS
TONIGHT...IN ADDITION TO MVFR FOG HAVE DEVELOPED AT KCDS. COMPUTER
MODELS CONTINUE TO HINT AT LIGHT -RA DEVELOPING INITIALLY AT KCDS
/WHICH IT HAS/...WITH PRECIP EXPANDING SOUTH AND WEST TO KLBB
THROUGHOUT THE NIGHT. FURTHERMORE...AS TEMPS COOL ALOFT AND AT THE
SFC...THE CHANCE FOR WINTRY PRECIP WILL BE POSSIBLE...ESPECIALLY
AS A BROAD UA TROUGH SWINGS ACROSS THE HIGH AND CENTRAL
PLAINS...WITH ITS SOUTHERN PERIPHERY HAVING THE POTENTIAL TO BRUSH
ACROSS THE SOUTHERN PLAINS. THUS...HAVE ADDED A TEMPO GROUP FOR -RAPL
AND -RASNPL AT KCDS AND KLBB RESPECTIVELY. RATHER BREEZY NORTH
WINDS WILL PERSIST TONIGHT WITH THE POTENTIAL FOR AWW CRITERIA
OCCURRING AT KLBB...ALTHOUGH CONFIDENCE IS NOT HIGH ENOUGH FOR AN
AWW ISSUANCE ATTM /WILL NEED TO KEEP A CLOSE EYE ON THE WIND
SPEEDS/. THEREAFTER...CLEARING SKIES FROM WEST TO EAST WILL OCCUR
BY MID-MORNING TOMORROW...WITH WIND SPEEDS EXPECTED TO DECLINE.
&&
.PREV DISCUSSION... /ISSUED 1024 PM CDT WED MAY 1 2013/
UPDATE...
STRONGER SURFACE PRESSURE GRADIENT GRADUALLY DEVELOPING AND WE ARE
SEEING MORE SITES REACHING WELL INTO WIND ADVISORY LEVELS VIA THE
WEST TEXAS MESONET. STRONGER WINDS ALSO DEVELOPING OVER CASTRO
COUNTY JUST SHY OF HIGH WIND WARNING LEVELS. WE OPTED TO EXPAND
THE HIGH WIND WARNING INTO CASTRO COUNTY AND THE WIND ADVISORY
ACROSS THE ROLLING PLAINS. THE LATEST WRF/NAM AND HRRR RUNS ARE
CONSISTENT BREAKING LIGHT PRECIPITATION OUT ACROSS MAINLY NORTHERN
ROLLING PLAINS BEFORE MIDNIGHT...THEN EXPANDING BACK OVER MUCH OF
OUR AREA EARLY THURSDAY UNTIL ABOUT MID THURSDAY MORNING WITH
COMBINATION OF ISENTROPIC UPGLIDE...SLOPED FRONTOGENETIC FORCING...
AND DEEPER SYNOPTIC FORCING WITH UPPER TROUGH SWINGING OVERHEAD.
MOISTURE REMAINS LIMITED MOSTLY AROUND 650-700 MB OR LOWER SO
PRECIPITATION TOTALS EXPECTED TO BE LIGHT...TRACE TO 10 HUNDREDTHS
OF AN INCH FOR THE MOST PART. WE INCREASED PRECIPITATION CHANCES
OVER MOST OF THE AREA LATER TONIGHT AND EARLY THURSDAY. PHASE
CONTINUES TO FAVOR A SLEET/LIQUID MIX BECOMING A SLEET/FROZEN/LIQUID
MIX ON THE CAP-ROCK EARLY THURSDAY. MOST AREAS OVER THE ROLLING
PLAINS SHOULD REMAIN LIQUID...WITH EXCEPTION OF NORTHERN ROLLING
PLAINS WHICH ALSO MAY SEE SLEET MIXING IN EARLY THURSDAY. WITH THE
LIGHT AMOUNTS WE HAVE OPTED FOR NO WINTER WEATHER HIGH-LITES...
ALTHOUGH A BAND OR TWO OF MODERATE INTENSITY PRECIPITATION WITH
TEMPERATURES HOVERING NEAR FREEZING EARLY THURSDAY HAS SOME
POTENTIAL FOR LIGHT ACCUMULATIONS OVER THE NORTH-CENTRAL TO
NORTHEAST PART OF OUR AREA. UPDATE HAS BEEN ISSUED. RMCQUEEN
PREV DISCUSSION... /ISSUED 332 PM CDT WED MAY 1 2013/
SHORT TERM...
A VERY DYNAMIC LATE SPRING STORM TO BRING STRONG NORTH WINDS AND
CHANCE FOR GENERALLY LIGHT RAIN AND EVEN POSSIBILITY OF LIGHT WINTRY
PRECIPITATION TO THE AREA. THE PARENT UPPER LOW/TROUGH CONTINUES TO
STRENGTHEN OVER THE INTER-MOUNTAIN WEST WHILE AT THE SFC THE STRONG
COLD FRONT HAS ALREADY CLEARED THE FCST AREA. MAIN THREAT LOOKING TO
BE WINDS AS VERY STRONG PRESSURE RISES ARE EXPECTED TO MOVE SWD DOWN
THE SRN HIGH PLAINS WITH A BARRIER JET LIKELY DEVELOPING JUST ON THE
LEE OF THE MOUNTAINS OF CNTL NM. COMBINATION WILL MEAN AT LEAST WIND
ADVISORY LEVEL WINDS FOR ALL OF THE AREA ON THE CAPROCK WITH GOOD
POTENTIAL FOR WARNING CRITERIA TO BE MET ACROSS THE NW /SPECIFICALLY
PARMER AND BAILEY COUNTIES/.
AS FOR PRECIP...HAVE BEEN CONCERNED WITH RECENT MODEL BIASES TOWARD
BEING TOO WET IN THE POST-FRONTAL AIR MASS AS THEY HAVE BEEN WITH
THE LAST SEVERAL OF THESE EVENTS. IN ESSENCE...IT APPEARS THAT THE
NAM IN PARTICULAR CONVERTS TOO MUCH OF THE LIFT FROM FRONTOGENETICAL
AND ISENTROPIC MECHANISMS TO PRECIPITATION POSSIBLY FROM TOO
AGGRESSIVELY MOISTENING THE DEEPENING COLD LAYER. INSTEAD RESULT HAS
TOO OFTEN BEEN ONLY LOW CLOUDS HIGHER THAN PROGGED AS STRONG COLD
AND DRY ADVECTION WORKS IN IN THE NEAR-SFC LAYER. IT APPEARS THAT
THIS EVENT MAY WORK SIMILARLY. EXCEPTION TODAY MAY BE THE STRENGTH
OF SRN EXTENT OF THE UPPER TROUGH TO THE WEST. Q-VECTOR PROGS
SUGGEST THE TAIL END OF THE LARGE SCALE ASCENT MAY BE FAR ENOUGH
SOUTH TO BRING AN ADDITIONAL PRECIPITATION GENERATION MECHANISM INTO
PLAY LATE TONIGHT THEN BLEEDING OVER PAST 12Z THURSDAY. IT DOES NOT
LOOK LIKE THE FORMER MECHANISMS WILL TEMPORALLY OVERLAP THE LATTER
ONE...BUT IT DOES OFFER AN ADDITIONAL MEANS BY WHICH SOME LIGHT
PRECIP MAY BE GENERATED. OVERALL...GIVEN SKEPTICISM IN RELATION TO
NAM BIASES IN PARTICULAR...WILL FAVOR THE LOWER POPS OF MAVMOS. THAT
MEANS A SMALL REDUCTION IN FCST POPS FOR TONIGHT INTO THURSDAY
MORNING. PROBLEMS PERSIST REGARDING PRECIP PHASE AS WELL. MODEL
SOUNDINGS SHOW POTENTIAL PRECIP GENERATION ZONE ALOFT BEING IN AN
AREA OF RELATIVE WARMTH WITH POTENTIAL FOR SUPERCOOLED DROPS TO FALL
THROUGH THE COLD AIR MASS AT AND JUST ABOVE THE SFC. THIS WOULD TEND
TO FAVOR DRIZZLE IF DRY SUB-CLOUD AIR DOES NOT WIN OUT. SITUATION
COULD CHANGE WITH LARGER SCALE ASCENT FROM THE UPPER TROUGH AND
POTENTIAL FOR IT TO COOL TEMPS ALOFT. THAT COULD LEAD TO SOME SNOW
MAKING INTO WHAT MAY OR MAY NOT BE A MID LEVEL WARM ZONE AT THAT
TIME. SFC TEMPS WOULD FAVOR SNOW OR SLEET IN THIS REGIME MOST LIKELY
ONLY ACROSS THE NWRN AND NCNTL ZONES LATE TONIGHT AND EARLY
THURSDAY. THUS...HAVE PULLED BACK THE WINTRY PRECIP MENTION A BIT
FROM PREVIOUS FCSTS.
FINAL ISSUE FOR TONIGHT IS POTENTIAL FOR A LIGHT FREEZE. THAT SEEMS
MOST LIKELY IN THOSE NWRN AND NCNTL ZONES JUST MENTIONED...AND
WILL ISSUE A FREEZE WARNING FOR THOSE AREAS...ALTHOUGH BETTER
CHANCE FOR A FREEZE OR EVEN HARD FREEZE COMES 24 HOURS LATER.
TEMPS TO BE SLOW TO RISE THURSDAY UNTIL SOME CLEARING CAN BEGIN
TO WORK IN FROM THE WEST DURING THE AFTN. FCST TEMPS WILL BE JUST
BELOW MOS NUMBERS FOR MUCH OF THE AREA.
LONG TERM...
ONE MORE LATE SEASON FREEZE LOOKS TO OCCUR FOR THE SOUTH
PLAINS...ROLLING PLAINS...AND EXTREME SOUTHERN TEXAS PANHANDLE
THURSDAY NIGHT INTO FRIDAY MORNING. AN UNSEASONABLY COLD AIRMASS
WILL BE LOCKED IN ACROSS THE AREA AS SURFACE RIDGING...LIGHT
WINDS...AND CLEAR SKIES PROMOTE STRONG RADIATIONAL COOLING.
FORECASTING BOTH LUBBOCK AND CHILDRESS TO SET DAILY RECORD LOW
TEMPERATURES OF 29 AND 31 RESPECTIVELY (RECORDS ARE 30 AND 34). WILL
KEEP PREVIOUSLY ISSUED FREEZE WATCH IN EFFECT FOR THE ENTIRE
FORECAST AREA.
TEMPERATURES WILL BEGIN WARMING FRIDAY AS WARM AIR PUMPS INTO THE
REGION ALOFT ALONG WITH DOWNSLOPING WINDS. READINGS WILL REBOUND
BACK INTO THE 60S FRIDAY...FOLLOWED BY 60S AND 70S FOR THE
WEEKEND...STILL BELOW NORMAL VALUES OF AROUND 80 FOR THIS TIME OF
YEAR. OVERNIGHT LOWS WILL REMAIN ABOVE FREEZING BEGINNING FRIDAY
NIGHT THROUGH THE REMAINDER OF THE EXTENDED...WITH THE ONE EXCEPTION
PERHAPS BEING FRIDAY NIGHT ACROSS THE EXTREME SOUTHWEST PANHANDLE
AND ADJACENT PORTIONS OF THE SOUTH PLAINS. UPPER LEVEL RIDGING WILL
BUILD IN THROUGHOUT THE WEEKEND RAISING HEIGHTS AND AIDING IN THIS
WARMING TREND...BUT A DISTURBANCE LOOKS TO ATTEMPT TO BREAK DOWN
THIS FEATURE BY LATE WEEKEND OR EARLY NEXT WEEK. MOISTURE WILL TRY
TO MAKE A RETURN...BUT NOWHERE NEAR ENOUGH TO WARRANT POPS AT THIS
TIME.
WILL HAVE TO CONTINUE MONITORING THE EVOLUTION OF AN UPPER LOW
ENTERING THE WESTERN COAST OF THE COUNTRY HEADING INTO THE TUESDAY
TIME-FRAME AND BEYOND. THE CURRENT RUN OF THE ECMWF HAS A PROGRESSIVE
SYSTEM MOVING TOWARD THE PLAINS AND DRAWING UP SOME MOISTURE FROM
THE SOUTH...WHILE THE LATEST GFS ESTABLISHES AN OMEGA BLOCKING
PATTERN NEAR THE HEART OF THE COUNTRY...THUS KEEPING THIS SYSTEM
CONFINED WEST OF THE ROCKIES. MUCH REFINEMENT TO COME IN SUBSEQUENT
FORECASTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 30 45 24 62 32 / 20 20 0 0 0
TULIA 31 44 26 61 34 / 50 40 0 0 0
PLAINVIEW 33 45 26 62 35 / 50 40 0 0 0
LEVELLAND 34 47 26 66 36 / 40 30 0 0 0
LUBBOCK 35 46 29 66 36 / 50 40 0 0 0
DENVER CITY 35 50 29 65 38 / 30 30 0 0 0
BROWNFIELD 35 48 29 66 38 / 40 30 0 0 0
CHILDRESS 37 47 31 62 38 / 60 60 0 0 0
SPUR 37 47 30 65 37 / 60 60 0 0 0
ASPERMONT 40 46 31 65 39 / 60 60 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
THE FOLLOWING ZONES: TXZ021>044.
WIND ADVISORY UNTIL 6 AM CDT THURSDAY FOR THE FOLLOWING ZONES:
TXZ023>026-028>044.
FREEZE WARNING FROM 4 AM TO 9 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: TXZ021>023-027-028.
HIGH WIND WARNING UNTIL 6 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: TXZ021-022-027.
&&
$$
29
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1142 PM CDT WED MAY 1 2013
.AVIATION...
PROBLEMATIC TAF FORECAST OVER THE NEXT 24-30 HOURS WITH TIMING AND
CATEGORY OF LOW CLOUDS AND THE TIMING OF THE FRONT AND PRECIP
CHANCES. ALL CONVECTION HAS STAYED WEST OF TAF SITES AND DO NOT
ANTICIPATE ANY IMPACTS FROM PRECIPITATION IN THE SHORT-TERM. COLD
FRONT HAS REACHED BOWIE...GRAHAM AND BRECKENRIDGE AND LATEST
TIMING BRINGS THE FRONT THROUGH THE METRO AROUND 9-11Z. WINDS ARE
CURRENTLY EAST AND SHOULD BACK A LITTLE TO THE NORTHEAST AND THEN
NORTHWEST WITH THE PASSAGE OF THE COLD FRONT. THIS IS EXPECTED TO
OCCUR AT WACO AN HOUR OR TWO LATER THAN DFW. LAMP AND MET
GUIDANCE ARE PESSIMISTIC WITH THE CIGS BEHIND THE FRONT AND QUICKLY
DROP CIGS INTO LOW MVFR OR IFR AFTER FROPA. CURRENT SURFACE OBS AND
HIGH-RES GUIDANCE FROM THE RAP AND WRF...INDICATE THIS IS NOT
ONGOING AND WILL STEER AWAY FROM THIS SOLUTION. WILL SHOW CIGS
GOING TO BKN025 AFTER FROPA AND THEN OVC010 AT 11Z. KEPT THE
FORECAST MVFR AND NOT IFR AS FORECAST SOUNDINGS FROM BOTH THE
RAP...WRF...AND NAM INDICATE THIS. THE RAW OUTPUT FROM THE NAM
HAS CLOUD BASES AT 1000-1200 FEET ALTHOUGH THE MOS IS FORECASTING
IFR. ANOTHER FACTOR AGAINST IFR WILL BE WIND SPEEDS. SPEEDS AROUND
DAYBREAK ARE EXPECTED TO INCREASE TO 19 KNOTS AND THEN CONTINUE TO
INCREASE TO 24 KNOTS WITH 34+ KNOT GUSTS. PREVIOUS TAF HAD VCSH
FROM FROPA THROUGH 00Z...BUT DO NOT THINK SHOWERS COVERAGE WILL BE
HIGH ENOUGH INITIALLY FOR A MENTION. THINK COVERAGE SHOULD
INCREASE TOMORROW AFTERNOON ONCE THE UPPER SUPPORT WILL ARRIVE AND
HAVE VCSH FROM 16Z UNTIL 00Z. WIND SPEEDS ARE EXPECTED TO SLOWLY
DECREASE TOMORROW NIGHT BUT WILL STILL REMAIN ABOVE 10 KNOTS WITH
CLEARING SKIES OVERNIGHT. THIS FORECAST WILL LIKELY CALL FOR
AMENDMENTS AND UPDATES WITH LATER TAF ISSUANCES.
HAMPSHIRE
&&
.UPDATE...
FINAL UPDATE REGARDING OUR WATCH FOR OUR FAR SOUTHWEST COUNTIES.
THE ATMOSPHERE IS CONTINUING TO STABILIZE EAST OF THE STORM
CLUSTER WEST OF GOLDTHWAITE. CANNOT RULE OUT A STRONG STORM MAKING
IT INTO LAMPASAS OR MILLS COUNTIES BUT SEVERE STORMS ARE NOT
EXPECTED ANYMORE. HAMILTON...MILLS...AND LAMPASAS COUNTIES HAVE
ALL BEEN REMOVED FROM THE WATCH WITH NO COUNTIES IN OUR CWA
REMAINING IN THE WATCH.
OVERNIGHT...AFOREMENTIONED STABILIZATION FROM THE UPPER LOW CLOSE
BY TO THE EAST SHOULD KEEP THE COLD FRONTAL PASSAGE RELATIVELY
INACTIVE AS IT MOVES THRU NORTH AND CENTRAL TEXAS BETWEEN MIDNIGHT
AND NOON THURSDAY. HAVE LEFT SLIGHT CHANCES FOR A FEW SHOWERS AND
MAYBE A THUNDERSTORM ACROSS BELL AND LAMPASAS COUNTIES. WIND
ADVISORY THURSDAY AND THE FREEZE WARNING ACROSS THE NORTHWEST
COUNTIES THURSDAY NIGHT STILL LOOK GOOD.
05/
&&
.PREV DISCUSSION... /ISSUED 310 PM CDT WED MAY 1 2013/
THE COLD FRONT HAS MOVED THROUGH TEXAS PANHANDLE AS I WRITE
THIS...AND IT CONTINUES TO MOVE SOUTHEAST. WINDS WILL LIKELY
SWITCH NORTHEAST AHEAD OF THE COLD FRONT AS THE LOW LEVEL FLOW
RESPONDS TO THE VERTICALLY STACKED SURFACE/UPPER LOW CURRENTLY ON
THE MS/LA BORDER. IT WILL BE HARD TO MISS THE FRONT THOUGH...WITH
A RAPID INCREASE IN WIND SPEED AND DROP IN TEMPERATURE AS THE
FRONT PASSES.
SUBSIDENCE HAS CREATED A STRONG CAP OVER MUCH OF NORTH
TEXAS...BUT IT IS WEAKER IN THE WESTERN COUNTIES. AS THE FRONT
MOVES SOUTHEAST...CONVECTION IS EXPECTED TO INITIATE SOMEWHERE
NEAR THE WICHITA FALLS AREA AND MOVE SOUTHWARD AS A MULTI-
CELLULAR COMPLEX. HAIL AND DAMAGING WINDS REMAIN THE MAIN SEVERE
THREATS IN THE WESTERN ZONES TONIGHT THROUGH THE EARLY MORNING
HOURS THURSDAY.
THE REST OF NORTH TEXAS WILL CERTAINLY SEE THE EFFECTS OF THE
REMARKABLY COLD AIR...BUT RAINFALL AMOUNTS WILL BE LOW. THIS IS
DUE TO THE LOUISIANA SYSTEM BLOCKING GULF MOISTURE FROM SURGING
INTO NORTH TEXAS AHEAD OF THE SYSTEM...AND THE LACK OF INSTABILITY
OVER MUCH OF THE AREA. EXCEPT IN WESTERN ZONES...PRECIP SHOULD BE
PREDOMINANTLY SHOWERS INSTEAD OF THUNDERSTORMS ALTHOUGH ISOLATED
THUNDER MAY BE HEARD THROUGH THURSDAY MORNING. PRECIP SHOULD BE IN
THE FORM OF ELEVATED SHOWERS FROM SUNRISE THURSDAY THROUGH FRIDAY
MORNING WHEN THE SYSTEM SHOULD EXIT THE AREA TO THE EAST.
WE HAVE ISSUED A WIND ADVISORY FOR ALL OF NORTH TEXAS...EXPECTING
NORTHWEST WINDS 25 TO 30 MPH WITH GUSTS OCCASIONALLY AS HIGH AS 40
MPH THURSDAY AFTERNOON. WINDS WILL MODERATE OVERNIGHT AND SHOULD
BE FAIRLY LIGHT BY FRIDAY MORNING. GIVEN THE COLD AIR...WIND
CHILLS WILL DROP INTO THE 20S IN SOME AREAS...AND WIDESPREAD
CHILLS INTO THE LOW 30S ARE EXPECTED. CLOUDS WILL ALSO BE THINNING
FROM WEST TO EAST EARLY FRIDAY AND WE HAVE ALSO ISSUED A FREEZE WATCH
FOR FRIDAY MORNING ALONG AND NORTHWEST OF A LINE FROM EASTLAND TO
GAINESVILLE...EXPECTING LOW TEMPERATURES TO DIP INTO THE LOW 30S
IN THOSE AREAS.
DRY COOL AIR AND CLEAR SKIES PLUS LIGHT WINDS WILL CREATE THE
OPPORTUNITY FOR COLD MORNINGS THROUGH SUNDAY...AND BOTH DFW AND
WACO WILL FLIRT WITH RECORD LOWS THROUGH THE WEEKEND. THE WEEKEND
IS STILL EXPECTED TO BE QUITE PLEASANT...WITH HIGHS NEAR 70 BOTH
DAYS. 84
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 50 50 37 62 43 / 20 40 20 5 0
WACO, TX 53 56 37 64 40 / 20 40 20 5 0
PARIS, TX 57 59 38 60 39 / 20 40 20 5 0
DENTON, TX 47 52 34 61 39 / 20 40 20 5 0
MCKINNEY, TX 51 54 35 62 39 / 20 40 20 5 0
DALLAS, TX 52 55 37 64 43 / 20 40 20 5 0
TERRELL, TX 59 59 37 63 38 / 20 40 20 5 0
CORSICANA, TX 59 59 38 63 40 / 20 40 20 5 0
TEMPLE, TX 53 57 37 64 41 / 30 40 20 5 0
MINERAL WELLS, TX 43 49 33 63 38 / 20 40 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 1 PM TO 9 PM CDT THURSDAY FOR TXZ091>095-
100>107-115>123-129>135-141>148-156>162-174-175.
FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR
TXZ091-092-100>102-115>117-129.
&&
$$
85/85
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
230 PM PDT THU MAY 2 2013
.SYNOPSIS...
A HIGH PRESSURE SYSTEM WITH GUSTY OFFSHORE WINDS WILL CAUSE WELL
ABOVE NORMAL TEMPERATURES THROUGH FRIDAY. THE HIGH WILL EXIT THE
REGION LATE FRIDAY AND TEMPERATURES WILL DROP ON SATURDAY. A LOW
PRESSURE SYSTEM WILL ARRIVE BY SUNDAY WITH POSSIBLE PRECIPITATION
THROUGH TUESDAY. THE TEMPERATURES WILL BE BELOW NORMAL INTO MIDWEEK.
&&
.SHORT TERM (TODAY-SUN)...THE SMOKE PLUME FROM THE SPRINGS FIRE IN
CAMARILLO IS EXPECTED TO CONTINUE A WEST NORTHWEST TRAJECTORY
OVERNIGHT AND POSSIBLY MOVE OVER THE COASTAL WATERS ALONG THE
CENTRAL COAST. LOW LEVEL CLOUD FIELD APPROACHING THE CENTRAL COAST
THIS AFTERNOON WILL LIKELY MOVE ASHORE THIS EVENING AND THEN SCOUR
OUT OR MOVE OFFSHORE OVERNIGHT AS THE NORTHEAST WINDS DEVELOP. THE
LATE MORNING TEMPERATURES WILL LIKELY BE THE HIGHEST FOR THE DAY
WITH BEACH LOCATIONS...LIKE PISMO BEACH...POSSIBLY REACHING THE
LOWER 80S. AND CENTRAL COAST INLAND AREAS WILL LIKELY CLIMB TO
RECORD HEAT FRIDAY AFTERNOON. PATCHY LOW LEVEL CLOUDS SOUTH OF THE
NORTHERN CHANNEL ISLANDS WILL CONTINUE TO APPROACH THE LA/VENTURA
COASTS THROUGH THIS AFTERNOON AND POSSIBLY MOVE INTO THE SANTA
MONICA BAY WITH DENSE FOG TONIGHT. OTHERWISE THE LATEST HRRR WAS
CONSISTENT WITH PREVIOUS RUNS AND ONSHORE WINDS WILL MOVE INTO THE
COASTAL VALLEYS WHILE THE STRONG NORTHEAST WINDS DIMINISH THROUGH
THE REMAINDER OF THIS AFTERNOON. THE NORTHEAST WINDS WILL LIKELY
PREVAIL INLAND OVERNIGHT AND AS THE SEABREEZE DISSIPATES THE
NORTHEAST WINDS WILL RETURN TO THE COAST. THE WINDS MAY STRENGTHEN
WITH GUSTS TO 45 MPH FRIDAY MORNING OVER THE HIGH COUNTRY WITH LOCAL
GUSTS TO 35 MPH IN THE INTERIOR COASTAL VALLEYS. A WIND ADVISORY MAY
BE ISSUED FOR THE HIGH COUNTRY FOLLOWING THE HIGH WIND WARNING
EXPIRATION AT 6 PM THIS EVENING. A COOLING TREND WILL OCCUR SATURDAY
THROUGH SUNDAY. ONSHORE WINDS WILL RETURN SATURDAY AND TEMPERATURES
WILL COOL THOUGH LIKELY REMAIN 5 TO 10 DEGREES ABOVE NORMAL SATURDAY
AND TO AT OR BELOW NORMAL SUNDAY. AN UPPER LEVEL LOW PRESSURE SYSTEM
CURRENTLY BETWEEN THE HAWAIIAN ISLANDS AND SOUTHERN CALIFORNIA WILL
APPROACH THROUGH SUNDAY. LATEST GUIDANCE DIFFERS FROM PREVIOUS RUNS
AND BETWEEN SUITES THOUGH SKIES WILL LIKELY BECOME CLOUDY AND A
CHANCE OF SHOWERS ARE EXPECTED SUNDAY.
.LONG TERM (MON-THU)...A STABLE TYPE PATTERN WITH A ANTICLONIC
CIRCULATION CENTERED OVER THE PAC NW AND CYCLONIC CIRCULATION OVER
THE SFO BAY AREA WILL DEVELOP SUNDAY AND PERSIST THROUGH WEDNESDAY.
ONE UPPER LEVEL TROUGH WILL ROTATE AND EXIT THROUGH THE SOLITON TYPE
FEATURE SUNDAY THROUGH MONDAY AND A SECOND ONE IS EXPECTED TUEDAY
NIGHT THROUGH WEDNESDAY. PARTLY TO MOSTLY CLOUDY SKIES ARE EXPECTED
WITH A SLIGHT CHANCE OF SHOWERS MONDAY THROUGH LATE TUESDAY EVENING.
TEMPERATURES WILL COOL THROUGH THE PERIOD AND LIKELY RANGE 4 TO 8
DEGREES BELOW SEASONAL NORMAL THROUGH THE PERIOD.
&&
.FIRE WEATHER...
RED FLAG WARNINGS IN EFFECT FOR MUCH OF LOS ANGELES AND VENTURA
COUNTIES THROUGH FRIDAY AS A MODERATE TO STRONG SANTA ANA WIND EVENT
AFFECTS SOUTHWEST CALIFORNIA. THE PEAK IN WIND SPEEDS IS OCCURRING
THIS MORNING...WITH GUSTS OF 65 TO 75 MPH OVER THE INTERIOR PEAKS OF
LA COUNTY...AND VALLEY LOCATIONS SEEING GUSTS OF 40 TO 60
MPH...STRONGEST IN THE SANTA CLARITA VALLEY AND THE EASTERN VENTURA
VALLEYS. GUSTS TO 45 MPH HAVE BEEN OBSERVED AS FAR WEST AS THE
VENTURA COUNTY COAST NEAR CAMARILLO. RELATIVE HUMIDITIES ARE VERY
LOW WITH MANY VALUES IN THE MID TO LOWER SINGLE DIGITS OBSERVED
ACROSS THE AREA. IN ADDITION...FUELS IN THE AREA ARE EXTREMELY DRY
FOR THIS TIME OF THE YEAR...AT VALUES THAT ARE MORE TYPICAL FOR MID
TO LATE SUMMERTIME. THE COMBINATION OF STRONG WIND GUSTS...LOW
HUMIDITIES AND VERY DRY FUELS HAS CREATED THE POTENTIAL FOR EXTREME
FIRE BEHAVIOR.
SURFACE PRESSURE GRADIENTS ARE BEGINNING TO EASE SLIGHTLY ACROSS
THE AREA...WHICH SHOULD ALLOW THE OFFSHORE WINDS TO BEGIN TO
DIMINISH ACROSS THE AREA BY EARLY THIS AFTERNOON. ALONG THE
IMMEDIATE COAST...ONSHORE WINDS HAVE BEEN OBSERVED IN SOME LOCATIONS
AND THERE IS A CHANCE THAT THE WEST TO SOUTHWEST FLOW WILL SPREAD
INLAND ACROSS THE COASTAL PLAIN OF LA AND VENTURA COUNTIES THIS
AFTERNOON INTO THIS EVENING. THE SOUTHWEST FLOW IS FORECAST BY THE
NAM12 MET GUIDANCE TO GUST UP TO AROUND 25 MPH. THE COASTAL WINDS
WILL SHIFT BACK TO OFFSHORE BY AROUND SUNRISE FRIDAY MORNING AND
INCREASE...BUT WITH LOWER SPEEDS THAN WHAT HAS BEEN OBSERVED TODAY.
HOWEVER...IN SPITE OF THE LOWER WINDS SPEEDS...VERY DRY CONDITIONS
AND EXTREME FIRE DANGER WILL CONTINUE THROUGH FRIDAY AFTERNOON.
HUMIDITY RECOVERIES OVERNIGHT WILL BE POOR IN MOST
AREAS...ESPECIALLY WHERE EXPOSED TO OFFSHORE WIND THROUGH THE NIGHT.
HUMIDITIES WILL FALL QUICKLY TO THE SINGLE DIGITS AGAIN FRIDAY
MORNING...WITH MINIMUM READINGS OF 5 PERCENT OR LOWER.
BY EARLY AFTERNOON A MORE WIDESPREAD WIND SHIFT TO THE SOUTHWEST TO
WEST IS EXPECTED. THIS WILL ALLOW HUMIDITIES TO BEGIN TO RISE ACROSS
A LARGER PORTION OF THE COASTAL PLAIN...AND THIS MAY ADVANCE INLAND
TO THE COASTAL VALLEYS OVERNIGHT.
.AVIATION...03/1745Z...
HIGH CONFIDENCE IN VFR CONDITIONS AT MOST SITES OVER THE NEXT 24
HOURS DUE TO THE ONGOING OFFSHORE EVENT. AN EXCEPTION THIS MORNING
IS OXR WHERE THE NORTHEAST WINDS ARE BLOWING SMOKE FROM A FIRE IN
CAMARILLO OVER THE AIRPORT. SOME OF THE GUIDANCE BRINGS MVFR
CONDITIONS INTO OXR AND LAX EARLY TOMORROW MORNING DUE TO BR OR
HZ...BUT THAT DOES NOT SEEM LIKELY WITH THE OFFSHORE FLOW.
KLAX...MODERATE-HIGH CONFIDENCE IN THE CURRENT TAF WITH VFR
CONDITIONS THRU FRIDAY MORNING. GUIDANCE BRINGS MVFR CONDITIONS IN
EARLY FRIDAY MORNING DUE TO BR AND HZ...BUT THAT DOES NOT SEEM
LIKELY WITH THE OFFSHORE FLOW.
KBUR...HIGH CONFIDENCE IN VFR CONDITIONS THRU FRIDAY MORNING. SOME
UNCERTAINTY IN WHETHER NORTHEAST WINDS WILL SURFACE THIS MORNING AND
EARLY THIS AFTERNOON.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
RED FLAG WARNING (SEE LAXRFWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...30
AVIATION...KJ
SYNOPSIS...SETO
FIRE...SMITH
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS MIAMI FL
501 PM EDT THU MAY 2 2013
.UPDATE...
A SMALL CRAFT ADVISORY IS IN EFFECT FROM 2 AM THIS MORNING TO 200
PM FRIDAY FOR THE ATLANTIC WATERS TO THE EAST OF PALM BEACH COUNTY. THE
COMBINATION OF WINDS FORECAST TO INCREASE TO THE 16 TO 21 KNOT
RANGE AND A SMALL LONG PERIOD SWELL WILL RESULT IN SEAS TO NEAR 7
FEET MAINLY EXPECTED TO THE EAST OF PALM BEACH COUNTY.
60
&&
.PREV DISCUSSION... /ISSUED 324 PM EDT THU MAY 2 2013/
DISCUSSION...
WIDESPREAD SHOWERS AND THUNDERSTORMS HAVE MOVED ACROSS SOUTH
FLORIDA TODAY. A WELL DEVELOPED MCS/MCV WAS MOVING ACROSS SOUTH
FLORIDA THIS AFTERNOON...AND SOME STORMS HAVE SHOWN ROTATION.
THERE WERE REPORTS OF DAMAGE FROM A STORM IN BOCA RATON EARLIER
THIS AFTERNOON AS WELL. SEVERE STREET FLOODING WAS REPORTED IN THE
BOCA RATON AND DELRAY BEACH AREAS...WHERE OVER 7.5 INCHES OF RAIN
HAS FALLEN.
A SURFACE BOUNDARY APPEARED TO BE DRIFTING SOUTH AND IT WAS
LOCATED ACROSS BROWARD COUNTY THIS AFTERNOON...AND LOCALLY HEAVY
RAIN AND FLOODING WILL BE POSSIBLE ACROSS BROWARD AND MIAMI DADE
COUNTY THROUGH THIS EVENING. AN UPPER LEVEL LOW ACROSS THE
NORTHEASTERN GULF WILL CONTINUE TO SLIDE SOUTHEAST AND OPEN INTO A
TROUGH OVERNIGHT AS IT MOVES INTO THE FLORIDA PENINSULA. UPPER
LEVEL DIVERGENCE FROM THIS UPPER LOW MAY HELP STORMS CONTINUE INTO
THE EVENING BEFORE DIMINISHING. THE HRRR SHOWS SHOWERS
DISSIPATING AFTER 00Z THIS EVENING.
SURFACE LOW PRESSURE IS EXPECTED TO DEVELOP ACROSS THE EASTERN
GULF OF MEXICO AND MOVE OVER SOUTH FLORIDA ON FRIDAY. THIS
WILL ALLOW THE STEERING FLOW OVER SOUTH FLORIDA TO REMAIN LIGHT
FROM A SOUTH TO SOUTHWEST DIRECTION KEEPING THE DEEP TROPICAL
MOISTURE IN PLACE. SO SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE REGION AGAIN ON FRIDAY. THE
EMPHASIS WILL BE FOR THE EAST COAST AND NORTHEAST COAST WHERE THE
BEST LOW LEVEL CONVERGENCE AND THE SURFACE BOUNDARY WILL BE
FOUND...ALONG WITH UPPER LEVEL FORCING ASSOCIATED WITH THE UPPER
LEVEL FLOW.
THE 500 MB TEMPS ON FRIDAY SHOULD BE A LITTLE BIT WARMER THAN
TODAY...DUE TO THE UPPER LEVEL LOW DISSIPATING OVER THE NORTHEAST
GULF OF MEXICO. HOWEVER...ANY STORMS THAT DO AFFECT SOUTH FLORIDA
TONIGHT INTO FRIDAY WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL.
THE LOW WILL CONTINUE TO MOVE EAST OVER SOUTH FLORIDA ON SATURDAY
BEFORE MOVING INTO THE WESTERN ATLANTIC WATERS ON SUNDAY. SLIGHTLY
DRIER CONDITIONS ARE EXPECTED ON SATURDAY...BUT RAIN CHANCES WILL
CONTINUE FOR THE NORTHERN TWO-THIRDS OF THE REGION. MUCH DRIER
AIR WILL WORK INTO THE AREA FROM THE WEST ON SUNDAY.
FOR EARLY TO MIDDLE OF NEXT WEEK...A MID TO UPPER LEVEL LOW WILL
DEVELOP OVER THE TENNESSEE VALLEY AND MOVE SLOWLY EAST TOWARDS THE
MID ATLANTIC STATES. THIS WILL ALLOW FOR DRIER WEATHER TO CONTINUE
TO WORK INTO SOUTH FLORIDA FROM THE WEST. SO THE WEATHER SHOULD
REMAIN DRY OVER SOUTH FLORIDA FOR THE EARLY TO MIDDLE PART OF NEXT
WEEK.
AVIATION...
LIGHT TO MODERATE RAIN WILL CONTINUE AT KAPF AND KPBI THROUGH
ABOUT 21-22Z. VERY HEAVY RAIN AND THUNDERSTORMS WILL CONTINUE FOR
THE REST OF THE EAST COAST TAF SITES...WHERE IFR CONDITIONS MAY
OCCUR. RAIN IS EXPECTED TO BEGIN DIMINISHING AFTER 04-06Z
TONIGHT...WITH IMPROVING CONDITIONS. STORMS WILL BE POSSIBLE AGAIN
BEGINNING LATE MORNING ON FRIDAY. WINDS WILL BE VARIABLE THE REST
OF THIS AFTERNOON WITH GUSTY WINDS POSSIBLE. LIGHT AND VARIABLE
WINDS ARE EXPECTED AFTER MIDNIGHT. WITH LOW PRESSURE MOVING OVER
SOUTH FLORIDA...WESTERLY WINDS ARE EXPECTED ON FRIDAY.
MARINE...
THE WINDS OVER SOUTH FLORIDA TODAY INTO FRIDAY WILL BE FROM THE
SOUTH TO SOUTHEAST DIRECTION AT 10 KNOTS OR LESS...BEFORE SLOWLY
SWINGING TO A NORTHWEST DIRECTION BY LATE THIS WEEKEND AND
INCREASING SPEEDS TO 10 TO 15 KNOTS. AT THE SAME TIME...A SMALL
NORTHEAST SWELL OF 1 TO 3 FEET WILL CONTINUE TO AFFECT THE
ATLANTIC WATERS OF SOUTH FLORIDA LATE THIS WEEK INTO THIS
WEEKEND. THESE CONDITIONS WILL ALLOW FOR THE ATLANTIC SEAS TO
REMAIN BELOW 6 FEET TODAY INTO THIS WEEKEND...EXCEPT FOR THE PALM
BEACH WATERS WHERE THE SEAS COULD BUILD TO 6 FEET THIS WEEKEND.
FOR THE GULF SIDE...THE SEAS WILL REMAIN BELOW 6 FEET TODAY INTO
THIS WEEKEND. THE ONLY EXCEPTION IS THE OFFSHORE GULF WATERS WHERE
THE SEAS COULD BUILD TO 6 FEET BY THIS WEEKEND.
FIRE WEATHER...
DEEP TROPICAL MOISTURE WILL REMAIN OVER THE REGION ON FRIDAY WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. SLIGHTLY DRIER
AIR WILL BEGIN TO MOVE INTO THE REGION ON SATURDAY...WITH LESSER
RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 83 69 87 / 80 70 40 30
FORT LAUDERDALE 72 83 73 88 / 80 60 30 20
MIAMI 72 84 72 87 / 80 60 30 10
NAPLES 67 83 68 87 / 40 50 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 AM TO 2 PM EDT
FRIDAY FOR COASTAL WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET TO DEERFIELD
BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS MIAMI FL
324 PM EDT THU MAY 2 2013
.DISCUSSION...
WIDESPREAD SHOWERS AND THUNDERSTORMS HAVE MOVED ACROSS SOUTH
FLORIDA TODAY. A WELL DEVELOPED MCS/MCV WAS MOVING ACROSS SOUTH
FLORIDA THIS AFTERNOON...AND SOME STORMS HAVE SHOWN ROTATION.
THERE WERE REPORTS OF DAMAGE FROM A STORM IN BOCA RATON EARLIER
THIS AFTERNOON AS WELL. SEVERE STREET FLOODING WAS REPORTED IN THE
BOCA RATON AND DELRAY BEACH AREAS...WHERE OVER 7.5 INCHES OF RAIN
HAS FALLEN.
A SURFACE BOUNDARY APPEARED TO BE DRIFTING SOUTH AND IT WAS
LOCATED ACROSS BROWARD COUNTY THIS AFTERNOON...AND LOCALLY HEAVY
RAIN AND FLOODING WILL BE POSSIBLE ACROSS BROWARD AND MIAMI DADE
COUNTY THROUGH THIS EVENING. AN UPPER LEVEL LOW ACROSS THE
NORTHEASTERN GULF WILL CONTINUE TO SLIDE SOUTHEAST AND OPEN INTO A
TROUGH OVERNIGHT AS IT MOVES INTO THE FLORIDA PENINSULA. UPPER
LEVEL DIVERGENCE FROM THIS UPPER LOW MAY HELP STORMS CONTINUE INTO
THE EVENING BEFORE DIMINISHING. THE HRRR SHOWS SHOWERS
DISSIPATING AFTER 00Z THIS EVENING.
SURFACE LOW PRESSURE IS EXPECTED TO DEVELOP ACROSS THE EASTERN
GULF OF MEXICO AND MOVE OVER SOUTH FLORIDA ON FRIDAY. THIS
WILL ALLOW THE STEERING FLOW OVER SOUTH FLORIDA TO REMAIN LIGHT
FROM A SOUTH TO SOUTHWEST DIRECTION KEEPING THE DEEP TROPICAL
MOISTURE IN PLACE. SO SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE REGION AGAIN ON FRIDAY. THE
EMPHASIS WILL BE FOR THE EAST COAST AND NORTHEAST COAST WHERE THE
BEST LOW LEVEL CONVERGENCE AND THE SURFACE BOUNDARY WILL BE
FOUND...ALONG WITH UPPER LEVEL FORCING ASSOCIATED WITH THE UPPER
LEVEL FLOW.
THE 500 MB TEMPS ON FRIDAY SHOULD BE A LITTLE BIT WARMER THAN
TODAY...DUE TO THE UPPER LEVEL LOW DISSIPATING OVER THE NORTHEAST
GULF OF MEXICO. HOWEVER...ANY STORMS THAT DO AFFECT SOUTH FLORIDA
TONIGHT INTO FRIDAY WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL.
THE LOW WILL CONTINUE TO MOVE EAST OVER SOUTH FLORIDA ON SATURDAY
BEFORE MOVING INTO THE WESTERN ATLANTIC WATERS ON SUNDAY. SLIGHTLY
DRIER CONDITIONS ARE EXPECTED ON SATURDAY...BUT RAIN CHANCES WILL
CONTINUE FOR THE NORTHERN TWO-THIRDS OF THE REGION. MUCH DRIER
AIR WILL WORK INTO THE AREA FROM THE WEST ON SUNDAY.
FOR EARLY TO MIDDLE OF NEXT WEEK...A MID TO UPPER LEVEL LOW WILL
DEVELOP OVER THE TENNESSEE VALLEY AND MOVE SLOWLY EAST TOWARDS THE
MID ATLANTIC STATES. THIS WILL ALLOW FOR DRIER WEATHER TO CONTINUE
TO WORK INTO SOUTH FLORIDA FROM THE WEST. SO THE WEATHER SHOULD
REMAIN DRY OVER SOUTH FLORIDA FOR THE EARLY TO MIDDLE PART OF NEXT
WEEK.
&&
.AVIATION...
LIGHT TO MODERATE RAIN WILL CONTINUE AT KAPF AND KPBI THROUGH
ABOUT 21-22Z. VERY HEAVY RAIN AND THUNDERSTORMS WILL CONTINUE FOR
THE REST OF THE EAST COAST TAF SITES...WHERE IFR CONDITIONS MAY
OCCUR. RAIN IS EXPECTED TO BEGIN DIMINISHING AFTER 04-06Z
TONIGHT...WITH IMPROVING CONDITIONS. STORMS WILL BE POSSIBLE AGAIN
BEGINNING LATE MORNING ON FRIDAY. WINDS WILL BE VARIABLE THE REST
OF THIS AFTERNOON WITH GUSTY WINDS POSSIBLE. LIGHT AND VARIABLE
WINDS ARE EXPECTED AFTER MIDNIGHT. WITH LOW PRESSURE MOVING OVER
SOUTH FLORIDA...WESTERLY WINDS ARE EXPECTED ON FRIDAY.
&&
.MARINE...
THE WINDS OVER SOUTH FLORIDA TODAY INTO FRIDAY WILL BE FROM THE
SOUTH TO SOUTHEAST DIRECTION AT 10 KNOTS OR LESS...BEFORE SLOWLY
SWINGING TO A NORTHWEST DIRECTION BY LATE THIS WEEKEND AND
INCREASING SPEEDS TO 10 TO 15 KNOTS. AT THE SAME TIME...A SMALL
NORTHEAST SWELL OF 1 TO 3 FEET WILL CONTINUE TO AFFECT THE
ATLANTIC WATERS OF SOUTH FLORIDA LATE THIS WEEK INTO THIS
WEEKEND. THESE CONDITIONS WILL ALLOW FOR THE ATLANTIC SEAS TO
REMAIN BELOW 6 FEET TODAY INTO THIS WEEKEND...EXCEPT FOR THE PALM
BEACH WATERS WHERE THE SEAS COULD BUILD TO 6 FEET THIS WEEKEND.
FOR THE GULF SIDE...THE SEAS WILL REMAIN BELOW 6 FEET TODAY INTO
THIS WEEKEND. THE ONLY EXCEPTION IS THE OFFSHORE GULF WATERS WHERE
THE SEAS COULD BUILD TO 6 FEET BY THIS WEEKEND.
&&
.FIRE WEATHER...
DEEP TROPICAL MOISTURE WILL REMAIN OVER THE REGION ON FRIDAY WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. SLIGHTLY DRIER
AIR WILL BEGIN TO MOVE INTO THE REGION ON SATURDAY...WITH LESSER
RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 83 69 87 / 80 70 40 30
FORT LAUDERDALE 72 83 73 88 / 80 60 30 20
MIAMI 72 84 72 87 / 80 60 30 10
NAPLES 67 83 68 87 / 40 50 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
356 PM CDT THU MAY 2 2013
.SYNOPSIS...
ISSUED AT 351 PM CDT THU MAY 2 2013
12Z UA ANALYSIS HAS 850MB LOWS ALONG THE KS/MO BORDER AND ANOTHER IN
WESTERN OKLAHOMA. A VERY STRONG 850MB THERMAL GRADIENT RAN FROM
MN/WI DOWN TO OKLAHOMA AND WEST TEXAS. SATELLITE TRENDS THROUGH MID
AFTERNOON SHOW THE LOW CLOUDS MAKING SLOW PROGRESS EASTWARD. RADAR
SHOWS THE MAIN RAIN SHIELD OVER CENTRAL AND NORTHEAST IOWA WITH
SCATTERED CONVECTION ACROSS ILLINOIS AND EASTERN IOWA.
18Z SFC ANALYSIS HAS WEAK LOWS FROM LOWER MICHIGAN BACK INTO
NORTHEAST ARKANSAS WITH THE FRONT CONNECTING ALL THE LOWS. DEW
POINTS ACROSS THE PLAINS AND PARTS OF THE UPPER MIDWEST WERE IN THE
20S AND 30S WITH 40S AND HIGHER FROM THE GREAT LAKES INTO THE LOWER
MISSISSIPPI VALLEY.
08
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 351 PM CDT THU MAY 2 2013
VERY DIFFICULT FCST. REFER TO THE CLIMATE SECTION FOR INFORMATION
REGARDING MAY SNOW FOR SOME LOCATIONS.
THE TRENDS WITH THE MODELS IS COLDER. THE MAIN PRECIPITATION SHIELD
IS ALONG AND BEHIND THE 850MB FRONT. THE RAP AND WRF TRENDS HAVE
THIS FRONT SLOWLY MOVING EAST TONIGHT. THUS RAIN WILL SLOWLY BREAK
OUT AND INCREASE IN AREAL COVERAGE DURING THE EVENING HOURS.
WBZ TEMPERATURES AND ACTUAL OBSERVATIONS SHOW TREMENDOUS EVAPORATIVE
COOLING WILL OCCUR ACROSS THE FAR NORTHWEST AND WESTERN PARTS OF THE
CWFA TONIGHT. FCST SOUNDINGS INDICATE RAIN BECOMING MIXED WITH AND
THEN CHANGING OVER TO SLEET/SNOW MIXTURE. THE OVERALL FORCING AND
WAA ALOFT IS SIGNIFICANT SO THERE WILL LIKELY BE ACCUMULATIONS ON
GRASSY SURFACES EVEN THOUGH THE GROUND IS QUITE WARM.
THEREFORE...WINTER WEATHER ADVISORIES HAVE BEEN RAISED FOR THE
WESTERN TWO ROWS OF COUNTIES FROM HWY 92 ON NORTH.
BUCHANAN...BENTON...IOWA...AND KEOKUK COUNTIES HAVE THE BEST CHANCE
AT SEEING POTENTIALLY HISTORIC SNOWFALL FOR MAY. THE HIGHEST
SNOWFALL AMOUNTS WILL BE IN THE WESTERN PARTS OF THESE COUNTIES.
SNOW/SLEET AMOUNTS THERE COULD RANGE FROM 1 TO 4 INCHES.
FURTHER EAST...ACROSS DELAWARE...LINN...JOHNSON...AND WASHINGTON
COUNTIES THE CHANGE OVER TO SLEET WILL OCCUR DURING THE EVENING. IN
THIS AREA MORE SLEET THAN SNOW IS EXPECTED WITH THE HIGHER AMOUNTS
IN THE WESTERN PARTS OF THESE COUNTIES. SNOW/SLEET AMOUNTS IN THIS
AREA COULD RANGE FROM A DUSTING TO 1 INCH.
THE OVERALL LARGE PICTURE SUGGESTS THE POTENTIAL FOR SOME SLEET AS
FAR EAST AS A DUBUQUE IOWA TO KAHOKA MISSOURI LINE DUE TO
EVAPORATIVE COOLING. IN THIS AREA ONLY TRACE AMOUNTS ARE EXPECTED.
ROUGHLY ALONG AND EAST OF THE MISSISSIPPI...SHOWERS WILL GIVE WAY TO
A WIDESPREAD RAIN AS THE WAA INCREASES.
FRIDAY...THE SNOW/SLEET MIXTURE IN THE FAR NORTHWEST/WEST PARTS OF
THE CWFA WILL CHANGE BACK TO ALL RAIN AS WARM AIR ALOFT MOVES INTO
THE AREA. ACROSS THE EASTERN CWFA THE OVERALL FORCING INCREASES AS A
SFC WAVE MOVES UP FROM THE SOUTH. ALTHOUGH NOT INCLUDED IN THE
FORECAST...THE LIFT TOOL SUGGESTS POSSIBLY SOME ISOLATED THUNDER
OVER THE FAR SOUTHEAST AND EASTERN PARTS OF THE CWFA AS STRONG
CONVERGENCE MOVES ALONG A THETA E GRADIENT.
08
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 351 PM CDT THU MAY 2 2013
RECORD COLD RAIN...SLEET...SNOW EVENT MAIN CHALLENGE THIS FORECAST.
OVERVIEW...INITIALIZATION AND VERIFICATION GOOD WITH MAIN ISSUE THE
PHASING OF LATENT HEAT RELEASE AND STRONG EVAPORATIVE COOLING TO
DETERMINE WHAT FAR WESTERN SECTIONS RECEIVE SLEET AND SNOW TONIGHT.
VERIFICATION AT 18Z SUPPORTS FORCING AND THERMAL FIELDS OF 12Z NAM-
WRF AND HI-RES ECMWF. THIS SUPPORTS SOME ACCUMULATIONS OF SNOW AND
QUITE A BIT OF SLEET FAR WEST SECTIONS. HEAVY RAIN AND FORCING
TOOLS SUGGEST MOST OF AREA TO PICK UP 1.5 TO LOCALLY AROUND 2.5
INCHES OF TOTAL PRECIPITATION NEXT 2-3 DAYS WITH MOST FALLING
FRIDAY AND FRIDAY NIGHT. STRATIFORM NATURE AND AMOUNTS OVER LONGER
TIME PERIOD SUPPORT MINOR RIVER ISSUES ON SOME RIVERS.
FRIDAY NIGHT...KEPT CATEGORICAL POPS WITH DEEPLY OCCLUDING AND
MATURING RAIN OF UPPER LOW TO DEPOSIT MOSTLY 1/3 TO 2/3 OF AN INCH
WITH HEAVIEST OVER SW 1/2 TO 2/3 OF AREAL TEMPERATURES WITH MILDER
AIR FROM EAST TO ALLOW TEMPERATURES TO BE NEARLY STEADY WITH LOWER
50S EAST TO MID/UPPER 40S FAR WEST.
SATURDAY AND SUNDAY...MINOR CHANGES MADE. CONSIDERABLE CLOUDS WITH
PERIODS OF LIGHT RAIN SATURDAY AND SATURDAY AND VERY LIGHT RAIN
SUNDAY. A QUARTER INCH OR LESS ON SATURDAY MOST LOCATIONS WITH
SPOTTY VERY LIGHT AMOUNTS SUNDAY. TEMPERATURES COOL WITH MOSTLY
LOWER TO MIDDLE 60S AND MINS SATURDAY NIGHT IN THE MID/UPPER 40S.
NICHOLS
DAYS 4 THROUGH 7...SUNDAY NIGHT THROUGH THURSDAY...
SUNDAY NIGHT THROUGH MONDAY NIGHT THE DEEP UPPER LOW GRADUALLY
SHIFTS SOUTHEAST...AND A SURFACE RIDGE BUILDS INTO THE AREA TO CAUSE
OUR SCATTERED SHOWERS TO SLOWLY DIMINISH IN COVERAGE...SO THAT BY
MONDAY NIGHT WE SHOULD BE COMPLETELY DRY. TEMPERATURES TO REMAIN
BELOW NORMAL WITH LOWS IN THE 40S. MONDAY HIGHS ARE CURRENTLY
FORECAST TO RISE INTO THE UPPER 60S...BUT IT TOO MUCH CLOUD COVER IS
LINGERING WILL HAVE TO LOWER THESE VALUES.
TUESDAY AND TUESDAY NIGHT THE SURFACE RIDGE SLOWLY SHIFTS EAST
ACROSS THE AREA...PRODUCING MAINLY DRY CONDITIONS AND GRADUALLY
WARMING TEMPERATURES. AM CARRYING SOME DAYTIME SLIGHT CHANCE POPS
IN THE SOUTHWEST CLOSEST TO THE LINGERING PLUME OF MOISTURE WHERE WE
MIGHT GET SOME DIURNALLY DRIVEN SHOWERS. HIGHS TUESDAY SHOULD GET
APPROACH 70 WITH 850MB TEMPERATURES GRADUALLY WARMING AS WELL.
TUESDAY NIGHT MINS TO MODERATE TO AROUND 50.
WEDNESDAY AND THURSDAY QUITE A BIT OF UNCERTAINTY RE-ENTERS THE
FORECAST. WE WILL BE IN A SPLIT FLOW WITH A NORTHERN STREAM MAINLY
AFFECTING SOUTHERN CANADA AND THE FAR NORTHERN CONUS...AND THE
SOUTHERN STREAM MAINLY AFFECTING THE SOUTHERN CONUS. MODELS ARE
DIVERGING IN THE HANDLING OF A SHORTWAVE THAT MOVES THROUGH THE
NORTHERN STREAM...AND HOW MUCH IT PHASES WITH A CUT OFF LOW IN THE
SOUTHERN STREAM OVER THE SOUTHWEST CONUS. THE ECMWF IS FASTER AND
IS PHASING IT MORE...AND DRAGGING MORE MOISTURE UP INTO THE
AREA...PRODUCING PRECIPITATION BEGINNING WEDNESDAY NIGHT. THE GFS
IS SLOWER AND PHASES IT LESS...AND DOES NOT BRING PRECIPITATION INTO
THE AREA UNTIL THURSDAY NIGHT. THUS...WHILE I AM CARRYING SOME
SLIGHT CHANCE POPS BEGINNING ON WEDNESDAY...THESE ARE MORE FOR A
CONTINUATION OF THE DIURNAL SHOWERS DURING THE DAY WITH THE
GRADUALLY INCREASING MOISTURE. AM BRINGING IN SOME LOW CHANCE POPS
FOR THURSDAY IN ASSOCIATION WITH THE NEW SHORTWAVE. TEMPERATURES TO
CONTINUE TO WARM THROUGH AT LEAST WEDNESDAY NIGHT...WITH HIGHS ON
WEDNESDAY INTO THE LOWER 70S. THURSDAY STILL FAIRLY WARM IN THE
FORECAST BUT THIS MAY NEED TO BE LOWERED IF PRECIPITATION MOVES INTO
THE AREA SOONER.
LE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 351 PM CDT THU MAY 2 2013
CONDITIONS RANGE FROM VFR TO IFR. MVFR/IFR CONDITIONS WILL
OVERSPREAD EASTERN IOWA AND NORTHERN ILLINOIS THROUGH 12Z/03 WITH
LIFR CONDITIONS LIKELY. ACCUMULATING SNPL IS VERY POSSIBLE AT KCID
AND MAY OCCUR AT KDBQ.
08
&&
.CLIMATE...
ISSUED AT 351 PM CDT THU MAY 2 2013
MAY SNOWFALL IN IOWA IS RARE.
A VERY QUICK LOOK BACK AT PAST WEATHER RECORDS SUGGESTS THAT THE
LAST TIME A FAIRLY WIDESPREAD SNOW OCCURRED IN MAY ACROSS IOWA WAS
IN 1966. BELOW IS WHEN MEASURABLE SNOW AND/OR SLEET FELL IN MAY
FOR SELECTED SITES.
CEDAR RAPIDS #1 (MARION)...
0.2 INCHES 05/01/1997 FELL AS SLEET
0.3 INCHES 05/11/1966
DUBUQUE IOWA...
3.1 INCHES 05/01/1966
1.0 INCHES 05/07-08/1960
IOWA CITY WWTP...
0.2 INCHES 05/05/1944
MOLINE ILLINOIS...
0.3 INCHES ON 05/03/1935
TRACE ON 05/06/1989
TRACE ON 05/22/1917*
* LATEST RECORDED SNOWFALL ON RECORD
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL 10 AM CDT FRIDAY FOR BENTON-
BUCHANAN-IOWA-KEOKUK.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 8 AM CDT
FRIDAY FOR DELAWARE-JOHNSON-LINN-WASHINGTON.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS/LE
AVIATION...08
CLIMATE...08
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
214 PM EDT THU MAY 2 2013
.SYNOPSIS...
ISSUED AT 421 AM EDT THU MAY 2 2013
A STRONG LOW PRESSURE SYSTEM WILL TAKE SHAPE ACROSS THE CENTRAL
PLAINS AND MID MISSISSIPPI VALLEY THROUGH THE WEEKEND...AS UPPER
LEVEL HIGH PRESSURE REMAINS PARKED ACROSS THE GREAT LAKES AND
NORTHEAST STATES. THIS WEATHER PATTERN WILL YIELD CONTINUED MILD
TEMPERATURES RIGHT ON THROUGH THE WEEKEND...WITH JUST A FEW SMALL
CHANCES FOR MAINLY AFTERNOON RAIN SHOWERS. DRY BUT CONTINUED WARM
WEATHER IS EXPECTED FOR MUCH OF NEXT WEEK...AS HIGH PRESSURE REMAINS
IN CONTROL ACROSS THE GREAT LAKES.
&&
.UPDATE...
ISSUED AT 211 PM EDT THU MAY 2 2013
DEWPOINTS QUICKLY MIXING OUT FROM GLR-GOV-MIO ALLOWING RH/S TO
REACH BELOW 30 PERCENT. THIS...COMBINED WITH TEMPERATURES NEAR 80
HAS RESULTED IN ELEVATED FIRE DANGER /WINDS NOT QUITE TO RED FLAG
CRITERIA/. WILL UPDATE FWF WITH THIS INFORMATION AS THIS SHOULD
CONTINUE THROUGH THE EARLY EVENING HOURS.
DEWPOINTS ALONG CONGESTED CU LINE STARTING TO FALL...SUGGESTING
OUR CONVECTIVE CHANCES ARE WANING...OUTSIDE OF ELEVATED CELLS
TAKING OFF OVER NORTHERN LAKE MICHIGAN...BUT LIKELY TO COME ASHORE
WEST OF CHIP AND MACK.
UPDATE ISSUED AT 100 PM EDT THU MAY 2 2013
CHANGES THIS HOUR: WILL CONTINUE TO EDGE THUNDERSTORM CHANCES WEST
GIVEN CURRENT SURFACE DEWPOINT ANALYSIS AS WELL AS EARLY AFTERNOON
VISIBLE SATELLITE IMAGERY SHOWING BEST CONGESTED CU IN THE HIGH
TERRAIN WEST AND SOUTH OF CADILLAC. COULD CERTAINLY SEE SOME
THUNDER IF CONVECTION CAN BREAK THE 50 J/KG CAPPING THAT REMAINS.
TEMPS A CHALLENGE WITH CAD-HTL-GOV LIKELY TO HIT 80...WITH
IMPRESSIVE DROP JUST TO THE NORTHWEST ACROSS THE SURFACE BOUNDARY.
REMAINDER OF FORECAST IN GOOD SHAPE.
UPDATE ISSUED AT 1018 AM EDT THU MAY 2 2013
CHANGES THIS HOUR: HAVE LOWERED HIGHS JUST A TAD AND DELAYED
SHOWER POTENTIAL TO PRIMARILY 18Z AND BEYOND. OTHERWISE...MINOR
CHANGES TO SKY TO ACCOUNT FOR STRATUS NEAR WHITEFISH POINT.
COOL FRONT SITS OVER THE CWA ATTM WITH 12Z APX RAOB SHOWING VERY
IMPRESSIVE...ALBEIT VERY SHALLOW SURFACE BASED INVERSION WITH T9
AT 19C AND +13C AT H8. BOUNDARY IS LIKELY TO MIX NORTH AND WEST
GIVEN AMPLE SURFACE BASED HEATING OVER NORTHERN LOWER HEADING INTO
EARLY AFTERNOON. SOME CAVEATS TO THIS...HOWEVER...INCLUDE
DEVELOPING MID CLOUDS FROM CAD TO CVX UNDER ISENTROPIC ASCENT AT
THIS LEVEL WHICH MAY HELP REINFORCE THE BOUNDARY IF IT CAN HOLD
TOGETHER. EXPECT THAT IT WILL NOT /OR MORE LIKELY THAT IT WILL
LIFT NORTH WITH TIME/...ALLOWING BOUNDARY TO PUSH TOWARDS THE
COAST OF NW LOWER. THIS SHOULD ALLOW TEMPS TO WORK TOWARDS
PREVIOUSLY FORECASTED HIGHS. CERTAINLY SOME TEMPERATURE BUST
POTENTIAL IN THE VICINITY OF WHERE THIS FRONT MIXES TO THIS
AFTERNOON /TVC-ACB-PLN/.
EARLY MORNING RAP SOUNDINGS HAVE A MUCH BETTER HANDLE ON MOISTURE
OVER ARRIVING AIRMASS FROM SOUTHEAST LOWER THAN THE NAM /12Z DTX
RAOB SHOWS 0C DEWPOINT AT H8...WITH 6C FROM THE NAM/. THE RESULT
OF THIS IS AN AFTERNOON CHARACTERIZED BY MORE MID 40S DEWPOINTS
THAN LOW 50S...REDUCING CONVECTIVE POTENTIAL. WILL THUS DELAY
POPS...BUT NOT PULL THEM AT THIS POINT...BUT AWAIT 12Z GUIDANCE
AND LATE MORNING OBSERVATIONAL TRENDS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 421 AM EDT THU MAY 2 2013
EARLY MORNING SURFACE ANALYSIS SHOWS A COLD/STATIONARY FRONT
EXTENDING FROM NORTHERN QUEBEC...SOUTHWEST ACROSS CENTRAL LOWER
MICHIGAN AND DOWN INTO NORTHWEST ILLINOIS/CENTRAL MISSOURI AND ON
INTO THE SOUTHERN PLAINS. THIS FRONT WAS ASSOCIATED WITH AN UPPER
LEVEL TROUGH ENCOMPASSING THE NATION`S MIDSECTION...AND ITS EASTWARD
PROGRESS WAS BEING IMPEDED BY A NARROW BUT HIGH AMPLITUDE BLOCKING
RIDGE OVER THE EASTERN THIRD OF THE NATION AND SUBSEQUENT TROUGHING
OVER THE WESTERN ATLANTIC. A 30-40 DEGREE TEMPERATURE CONTRAST
EXISTS ACROSS THE FRONT...WITH AN ELONGATED BAND OF POST-FRONTAL
RAIN AND SNOW FROM THE CENTRAL/SOUTHERN PLAINS NORTHWARD INTO THE
UPPER MISSISSIPPI VALLEY. CLOSER TO HOME...SCATTERED CONVECTION
DEVELOPED EARLIER ACROSS EASTERN UPPER MICHIGAN/NORTHERN LAKE
MICHIGAN...THE TAIL END OF A BAND OF SCATTERED SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHEAST ONTARIO. OTHERWISE SKIES ARE
CLEAR/PARTLY CLOUDY ACROSS NORTHERN LOWER.
STURDY RIDGE TO THE EAST WILL KEEP THINGS IN A HOLDING PATTERN
TODAY...STATIONARY FRONT WILL LIKELY WAVER A BIT DUE TO MIXING AND
LAKE BREEZE EFFECTS...BUT IS GOING TO ESSENTIALLY BISECT LOWER
MICHIGAN FROM NORTH TO SOUTH THROUGH THE SHORT TERM PERIOD. THIS
PRODUCES A MYRIAD OF FORECAST ISSUES FOR TODAY AND TONIGHT WITH
REGARD TO PRECIP CHANCES...TEMPERATURES...AND WINDS.
PRECIP ISSUES TODAY ARE PROBABLY GOING TO BE SIMILAR TO THOSE OF
WEDNESDAY...THAT IS WILL THERE BE ENOUGH MOISTURE TO GENERATE
INSTABILITY ALONG THE FRONT. FIRST...EXPECT THE FRONT TO MIX BACK
TO THE WEST...PROBABLY BACK TOWARD GLR-GOV-CAD THOUGH NORTHERN END
OF THE FRONT WILL PROBABLY BE DEFORMED IN AN EAST-WEST DIRECTION AS
LAKE HURON BREEZE RAMPS UP. THERE ARE INDICATIONS IN THE FORECAST
SOUNDINGS...PARTICULARLY THE GFS...OF STRATUS DEVELOPING ON THE COOL
SIDE OF THE FRONT VERY SHORTLY. THERE AREN`T ANY INDICATIONS OF
SUCH AS YET...SO WILL START OUT BY DOWNPLAYING THIS IDEA INITIALLY.
CAN SEE THE POSSIBILITY OF LOW CLOUDS DEVELOPING LATER THIS MORNING
AS THERMAL CONTRAST TIGHTENS...SUCH A SCENARIO IS MORE LIKELY OVER
THE COLD WATERS OF LAKE MICHIGAN AND PERHAPS SPILLING INTO ADJACENT
LAKESHORE AREAS OF NORTHWEST LOWER. SO WITH THE FRONT BACKING
TOWARD NORTHWEST LOWER...WILL PROBABLY TAKE DEW POINTS REMAINING IN
THE LOWER 50S TO GENERATE AROUND 500J/KG MLCAPE. TOOK ALL AFTERNOON
YESTERDAY TO GENERATE ONE SHOWER DURING THE EARLY EVENING...WONDER
IF WE`LL BE FACING THE SAME ISSUE TODAY. CURRENT THINKING IS THAT
IT IS CLOSE ENOUGH TO JUSTIFY CHANCE AFTERNOON POPS ACROSS MUCH OF
INTERIOR NORTHERN LOWER. ANOTHER POSSIBILITY FOR NORTHWEST LOWER IS
THAT UNSTABLE WARM SECTOR PARCELS ARE PULLED UP THE FRONTAL ZONE AND
CONVECT ON THE COOL SIDE OF THE BOUNDARY (ALONG/WEST OF US-131
CORRIDOR). SO SEVERAL POSSIBILITIES HERE. AS FOR TEMPERATURES
TODAY...AGAIN WILL VARY WIDELY DEPENDING ON LOCATION RELATIVE TO THE
FRONT AND LAKE BREEZE ACTIVITY. DON`T SEE WHY TEMPERATURES ON THE
WARM SIDE OF THE BOUNDARY WON`T MAKE ANOTHER RUN AT 80+ TODAY AS
CLOUD COVER SHOULD NOT BE MUCH OF AN ISSUE. RECORD HIGHS ARE A BIT
WARMER THAN YESTERDAY (APN 86/2001...HTL 88/1959...GLR 85/1959)...
AND WILL TAKE SOME TIME TO MIX THROUGH THE FRONTAL INVERSION SO
SHOULD BE A LITTLE SLOWER TEMPERATURE CLIMB THIS MORNING.
FOR TONIGHT...WILL BE DEALING BOTH WITH DEEPER MOISTURE NUDGING INTO
WESTERN PORTIONS OF THE FORECAST AREA AS WELL AS ELEVATED
INSTABILITY AND CONTINUE WARM ADVECTION. MUCH OF THE MOISTURE WILL
BE ACROSS THE WESTERN HALF OF THE FORECAST AREA AND THUS HIGHER
POPS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EDT THU MAY 2 2013
SPRING LOOKS LIKE IT`S HERE TO STAY FOR THE FORESEEABLE FUTURE...
WITH ACTUALLY VERY FEW FORECAST ISSUES NOTED THROUGH THE WEEKEND AND
MAJORITY OF NEXT WORK WEEK. OVERALL UPPER PATTERN IS PROGGED BY ALL
AVAILABLE MEDIUM RANGE GUIDANCE TO REMAIN HEAVILY BLOCKED UP AS
CLOSED LOW DEVELOPMENT TAKES PLACE OVER THE MID MISSISSIPPI
VALLEY...WHILE ANOTHER CLOSED LOW MEANDER OVER THE WESTERN
ATLANTIC...EFFECTIVELY PINNING A RATHER EXPANSIVE OMEGA-TYPE RIDGE
IN PLACE FROM FLORIDA RIGHT ON UP THROUGH THE GREAT LAKES AND MUCH
OF EASTERN CANADA. THAT RIDGE SHOULD INCREASINGLY BECOME CUT OFF
OVER THE NORTHERN TIER FOR THE FIRST PART OF NEXT WEEK...AS THE
CLOSED LOW WANDERS RATHER AIMLESSLY SOMEWHERE TO OUR SOUTH (EXACT
POSITION STILL TO BE DETERMINED). AS THAT OCCURS...PREVAILING SOUTH
TO SOUTHEASTERLY LOW LEVEL FLOW WILL CONTINUE TO TRANSPORT SOME
RATHER MILD AIR NORTHWARD AS A PERSISTENT THERMAL RIDGE FEATURE
HOLDS INTACT ACROSS THE GREAT LAKES...FAVORING SOME MORE MUCH NEEDED
(AND LET`S FACE IT...MUCH DESERVED) WARM SPRINGTIME WEATHER FOR THE
NORTH WOODS.
LOOKING AT SOME SPECIFICS...STALLED FRONTAL BOUNDARY/INVERTED
TROUGH AXIS REMAINS PROGGED TO RESIDE ACROSS THE AREA THROUGH
FRIDAY...EFFECTIVELY SPLITTING THE STATE IN HALF. GIVEN YESTERDAY`S
HISTORY WITH THIS BOUNDARY COUPLED WITH AN INCREASINGLY DRIER
BOUNDARY LAYER LIKELY TO BE SHUNTED INTO THE REGION ON SLOWLY
BACKING SOUTHEAST FLOW REGIME...HAVE SOME DIFFICULTY BELIEVING WE
WILL BE ABLE TO MUSTER MUCH IN THE WAY OF ANY AFTERNOON CONVECTION.
WITH THAT SAID...THE CHANCE IS NOT COMPLETELY ZERO WITH A LIGHT
WIND/LAKE BREEZE REGIME FAVORING ENHANCED CONVERGENCE INTO THE
SLUGGISH SYNOPTIC BOUNDARY...AND AT LEAST DECENT HEATING ACROSS
NORTHEAST LOWER AND THE HIGHER TERRAIN.
THEREAFTER...JUST CANNOT JUSTIFY HAVING ANY POPS IN THE FORECAST
BEYOND FRIDAY EVENING...AS THE ENTIRE PATTERN SLOWLY RETROGRADES AND
THE BEST MOISTURE AXIS SLIPS WELL TO OUR WEST...ALL WHILE AN
INCREASINGLY DRY BOUNDARY LAYER MAKES AN APPEARANCE THROUGH THE
WEEKEND. LOOKING INTO NEXT WEEK...DEEPER MOISTURE AXIS SHOULD REMAIN
WELL TO OUR SOUTH AS THE UPPER LOW PINWHEELS THROUGH THE TENNESSEE
VALLEY (OR SOMEWHERE NEAR THERE)...WITH DRY EASTERLY FLOW PREVAILING
UP THIS WAY AND SUBSIDENCE ON THE NORTHERN FRINGE OF CLOSED LOW
FEATURE FAVORING LOTS OF SUNSHINE. HIGHS SHOULD RESPOND NICELY INTO
THE 60S TO MIDDLE 70S EACH AFTERNOON...COOLER NEAR THE LAKESHORES OF
COURSE WHERE LAKE BREEZE DEVELOPMENT IS LIKELY EACH DAY GIVEN A VERY
WEAK GRADIENT IN PLACE. OVERNIGHT LOWS ARE A BIT MORE TRICKY IN THIS
LIGHT GRADIENT SETUP...AS DAILY MIXING OF DEW POINTS INTO THE 40S
AND MAYBE 30S AND CLEAR SKIES SHOULD EASILY ALLOW READINGS TO DIP
QUICKLY AFTER SUNSET. SIMPLY PUT...THE WEATHER THROUGH NEXT WEEK
LOOKS DOWNRIGHT SPECTACULAR FOR ALL OF NORTHERN MICHIGAN...WITH WARM
SUNNY DAYS AND COOL COMFORTABLE NIGHTS. ENJOY!
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM EDT THU MAY 2 2013
SUMMARY: A STALLED FRONTAL SYSTEM WILL REMAIN JUST WEST OF
NORTHERN MICHIGAN THROUGH THE UPCOMING TAF PERIOD. THIS WILL BRING
THE CHANCE FOR SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS TO
MBL-TVC-PLN THROUGH 18Z FRIDAY.
RESTRICTIONS:VFR CONDITIONS ONGOING AND EXPECTED TO CONTINUE INTO
THIS EVENING. SOME SHRA/TSRA DEVELOPMENT POSSIBLE FROM TVC SOUTH
TO CAD THIS EVENING. WILL INCLUDE TEMPO MENTION AT MBL-TVC...BUT
REFRAIN FROM INCLUDING THUNDER AT THIS POINT GIVEN LACKLUSTER
INSTABILITY AND LOW CONFIDENCE IN THUNDER OCCURRENCE. OVERNIGHT...
PRIMARY CONCERN IS FOR THE DEVELOPMENT OF STRATUS OVER NORTHWEST
LOWER MICHIGAN. WILL INCLUDE THIS AFTER MIDNIGHT AT MBL/TVC...BUT
CONFIDENCE IS BELOW AVERAGE ON OCCURRENCE. ANY STRATUS SHOULD
QUICKLY MIX OUT FRIDAY MORNING WITH VFR CONDITIONS RESUMING THOUGH
THE END OF THE FORECAST PERIOD.
WINDS: CURRENTLY DOMINATED BY LOCAL LAKE BREEZES 10G15KTS THROUGH
LATE AFTERNOON WILL BECOME LIGHT/VARIABLE TONIGHT BEFORE MORE
NORTHEASTERLY WINDS AROUND 10KTS TAKE OVER FOR THE DAY ON FRIDAY
/EXCEPT AT APN WHERE A SOUTHEAST DIRECTION WILL CONTINUE/.
&&
.MARINE...
ISSUED AT 421 AM EDT THU MAY 2 2013
STATIONARY FRONT BISECTING LOWER MICHIGAN FROM NORTH TO SOUTH WILL
PRODUCE VERY DIFFERENT WIND CONDITIONS BETWEEN WHITEFISH BAY/LAKE
MICHIGAN AND LAKE HURON NEARSHORE ZONES...EVEN ON LAKE HURON
CONDITIONS WILL VARY QUITE A BIT. WESTERN ZONES WILL BE DEALING
WITH A STRONGER NORTHERLY GRADIENT ON THE COOLER SIDE OF THE
BOUNDARY...MAY PUSH SMALL CRAFT CONDITIONS WITHIN NORTHWEST LOWER
NEARSHORE ZONES. ON LAKE HURON...WINDS WILL VARY FROM A NORTHERLY
COMPONENT NORTH OF THUNDER BAY...AND A SOUTHERLY COMPONENT SOUTH
THOUGH BOTH AREAS WILL BE IMPACTED LOCALLY BY LAKE BREEZE COMPONENTS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ323-
344>346.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...DL
SHORT TERM...JPB
LONG TERM...DL
AVIATION...ARNOTT
MARINE...JPB
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
149 PM EDT THU MAY 2 2013
.SYNOPSIS...
ISSUED AT 421 AM EDT THU MAY 2 2013
A STRONG LOW PRESSURE SYSTEM WILL TAKE SHAPE ACROSS THE CENTRAL
PLAINS AND MID MISSISSIPPI VALLEY THROUGH THE WEEKEND...AS UPPER
LEVEL HIGH PRESSURE REMAINS PARKED ACROSS THE GREAT LAKES AND
NORTHEAST STATES. THIS WEATHER PATTERN WILL YIELD CONTINUED MILD
TEMPERATURES RIGHT ON THROUGH THE WEEKEND...WITH JUST A FEW SMALL
CHANCES FOR MAINLY AFTERNOON RAIN SHOWERS. DRY BUT CONTINUED WARM
WEATHER IS EXPECTED FOR MUCH OF NEXT WEEK...AS HIGH PRESSURE REMAINS
IN CONTROL ACROSS THE GREAT LAKES.
&&
.UPDATE...
ISSUED AT 100 PM EDT THU MAY 2 2013
CHANGES THIS HOUR: WILL CONTINUE TO EDGE THUNDERSTORM CHANCES WEST
GIVEN CURRENT SURFACE DEWPOINT ANALYSIS AS WELL AS EARLY AFTERNOON
VISIBLE SATELLITE IMAGERY SHOWING BEST CONGESTED CU IN THE HIGH
TERRAIN WEST AND SOUTH OF CADILLAC. COULD CERTAINLY SEE SOME
THUNDER IF CONVECTION CAN BREAK THE 50 J/KG CAPPING THAT REMAINS.
TEMPS A CHALLENGE WITH CAD-HTL-GOV LIKELY TO HIT 80...WITH
IMPRESSIVE DROP JUST TO THE NORTHWEST ACROSS THE SURFACE BOUNDARY.
REMAINDER OF FORECAST IN GOOD SHAPE.
UPDATE ISSUED AT 1018 AM EDT THU MAY 2 2013
CHANGES THIS HOUR: HAVE LOWERED HIGHS JUST A TAD AND DELAYED
SHOWER POTENTIAL TO PRIMARILY 18Z AND BEYOND. OTHERWISE...MINOR
CHANGES TO SKY TO ACCOUNT FOR STRATUS NEAR WHITEFISH POINT.
COOL FRONT SITS OVER THE CWA ATTM WITH 12Z APX RAOB SHOWING VERY
IMPRESSIVE...ALBEIT VERY SHALLOW SURFACE BASED INVERSION WITH T9
AT 19C AND +13C AT H8. BOUNDARY IS LIKELY TO MIX NORTH AND WEST
GIVEN AMPLE SURFACE BASED HEATING OVER NORTHERN LOWER HEADING INTO
EARLY AFTERNOON. SOME CAVEATS TO THIS...HOWEVER...INCLUDE
DEVELOPING MID CLOUDS FROM CAD TO CVX UNDER ISENTROPIC ASCENT AT
THIS LEVEL WHICH MAY HELP REINFORCE THE BOUNDARY IF IT CAN HOLD
TOGETHER. EXPECT THAT IT WILL NOT /OR MORE LIKELY THAT IT WILL
LIFT NORTH WITH TIME/...ALLOWING BOUNDARY TO PUSH TOWARDS THE
COAST OF NW LOWER. THIS SHOULD ALLOW TEMPS TO WORK TOWARDS
PREVIOUSLY FORECASTED HIGHS. CERTAINLY SOME TEMPERATURE BUST
POTENTIAL IN THE VICINITY OF WHERE THIS FRONT MIXES TO THIS
AFTERNOON /TVC-ACB-PLN/.
EARLY MORNING RAP SOUNDINGS HAVE A MUCH BETTER HANDLE ON MOISTURE
OVER ARRIVING AIRMASS FROM SOUTHEAST LOWER THAN THE NAM /12Z DTX
RAOB SHOWS 0C DEWPOINT AT H8...WITH 6C FROM THE NAM/. THE RESULT
OF THIS IS AN AFTERNOON CHARACTERIZED BY MORE MID 40S DEWPOINTS
THAN LOW 50S...REDUCING CONVECTIVE POTENTIAL. WILL THUS DELAY
POPS...BUT NOT PULL THEM AT THIS POINT...BUT AWAIT 12Z GUIDANCE
AND LATE MORNING OBSERVATIONAL TRENDS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 421 AM EDT THU MAY 2 2013
EARLY MORNING SURFACE ANALYSIS SHOWS A COLD/STATIONARY FRONT
EXTENDING FROM NORTHERN QUEBEC...SOUTHWEST ACROSS CENTRAL LOWER
MICHIGAN AND DOWN INTO NORTHWEST ILLINOIS/CENTRAL MISSOURI AND ON
INTO THE SOUTHERN PLAINS. THIS FRONT WAS ASSOCIATED WITH AN UPPER
LEVEL TROUGH ENCOMPASSING THE NATION`S MIDSECTION...AND ITS EASTWARD
PROGRESS WAS BEING IMPEDED BY A NARROW BUT HIGH AMPLITUDE BLOCKING
RIDGE OVER THE EASTERN THIRD OF THE NATION AND SUBSEQUENT TROUGHING
OVER THE WESTERN ATLANTIC. A 30-40 DEGREE TEMPERATURE CONTRAST
EXISTS ACROSS THE FRONT...WITH AN ELONGATED BAND OF POST-FRONTAL
RAIN AND SNOW FROM THE CENTRAL/SOUTHERN PLAINS NORTHWARD INTO THE
UPPER MISSISSIPPI VALLEY. CLOSER TO HOME...SCATTERED CONVECTION
DEVELOPED EARLIER ACROSS EASTERN UPPER MICHIGAN/NORTHERN LAKE
MICHIGAN...THE TAIL END OF A BAND OF SCATTERED SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHEAST ONTARIO. OTHERWISE SKIES ARE
CLEAR/PARTLY CLOUDY ACROSS NORTHERN LOWER.
STURDY RIDGE TO THE EAST WILL KEEP THINGS IN A HOLDING PATTERN
TODAY...STATIONARY FRONT WILL LIKELY WAVER A BIT DUE TO MIXING AND
LAKE BREEZE EFFECTS...BUT IS GOING TO ESSENTIALLY BISECT LOWER
MICHIGAN FROM NORTH TO SOUTH THROUGH THE SHORT TERM PERIOD. THIS
PRODUCES A MYRIAD OF FORECAST ISSUES FOR TODAY AND TONIGHT WITH
REGARD TO PRECIP CHANCES...TEMPERATURES...AND WINDS.
PRECIP ISSUES TODAY ARE PROBABLY GOING TO BE SIMILAR TO THOSE OF
WEDNESDAY...THAT IS WILL THERE BE ENOUGH MOISTURE TO GENERATE
INSTABILITY ALONG THE FRONT. FIRST...EXPECT THE FRONT TO MIX BACK
TO THE WEST...PROBABLY BACK TOWARD GLR-GOV-CAD THOUGH NORTHERN END
OF THE FRONT WILL PROBABLY BE DEFORMED IN AN EAST-WEST DIRECTION AS
LAKE HURON BREEZE RAMPS UP. THERE ARE INDICATIONS IN THE FORECAST
SOUNDINGS...PARTICULARLY THE GFS...OF STRATUS DEVELOPING ON THE COOL
SIDE OF THE FRONT VERY SHORTLY. THERE AREN`T ANY INDICATIONS OF
SUCH AS YET...SO WILL START OUT BY DOWNPLAYING THIS IDEA INITIALLY.
CAN SEE THE POSSIBILITY OF LOW CLOUDS DEVELOPING LATER THIS MORNING
AS THERMAL CONTRAST TIGHTENS...SUCH A SCENARIO IS MORE LIKELY OVER
THE COLD WATERS OF LAKE MICHIGAN AND PERHAPS SPILLING INTO ADJACENT
LAKESHORE AREAS OF NORTHWEST LOWER. SO WITH THE FRONT BACKING
TOWARD NORTHWEST LOWER...WILL PROBABLY TAKE DEW POINTS REMAINING IN
THE LOWER 50S TO GENERATE AROUND 500J/KG MLCAPE. TOOK ALL AFTERNOON
YESTERDAY TO GENERATE ONE SHOWER DURING THE EARLY EVENING...WONDER
IF WE`LL BE FACING THE SAME ISSUE TODAY. CURRENT THINKING IS THAT
IT IS CLOSE ENOUGH TO JUSTIFY CHANCE AFTERNOON POPS ACROSS MUCH OF
INTERIOR NORTHERN LOWER. ANOTHER POSSIBILITY FOR NORTHWEST LOWER IS
THAT UNSTABLE WARM SECTOR PARCELS ARE PULLED UP THE FRONTAL ZONE AND
CONVECT ON THE COOL SIDE OF THE BOUNDARY (ALONG/WEST OF US-131
CORRIDOR). SO SEVERAL POSSIBILITIES HERE. AS FOR TEMPERATURES
TODAY...AGAIN WILL VARY WIDELY DEPENDING ON LOCATION RELATIVE TO THE
FRONT AND LAKE BREEZE ACTIVITY. DON`T SEE WHY TEMPERATURES ON THE
WARM SIDE OF THE BOUNDARY WON`T MAKE ANOTHER RUN AT 80+ TODAY AS
CLOUD COVER SHOULD NOT BE MUCH OF AN ISSUE. RECORD HIGHS ARE A BIT
WARMER THAN YESTERDAY (APN 86/2001...HTL 88/1959...GLR 85/1959)...
AND WILL TAKE SOME TIME TO MIX THROUGH THE FRONTAL INVERSION SO
SHOULD BE A LITTLE SLOWER TEMPERATURE CLIMB THIS MORNING.
FOR TONIGHT...WILL BE DEALING BOTH WITH DEEPER MOISTURE NUDGING INTO
WESTERN PORTIONS OF THE FORECAST AREA AS WELL AS ELEVATED
INSTABILITY AND CONTINUE WARM ADVECTION. MUCH OF THE MOISTURE WILL
BE ACROSS THE WESTERN HALF OF THE FORECAST AREA AND THUS HIGHER
POPS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EDT THU MAY 2 2013
SPRING LOOKS LIKE IT`S HERE TO STAY FOR THE FORESEEABLE FUTURE...
WITH ACTUALLY VERY FEW FORECAST ISSUES NOTED THROUGH THE WEEKEND AND
MAJORITY OF NEXT WORK WEEK. OVERALL UPPER PATTERN IS PROGGED BY ALL
AVAILABLE MEDIUM RANGE GUIDANCE TO REMAIN HEAVILY BLOCKED UP AS
CLOSED LOW DEVELOPMENT TAKES PLACE OVER THE MID MISSISSIPPI
VALLEY...WHILE ANOTHER CLOSED LOW MEANDER OVER THE WESTERN
ATLANTIC...EFFECTIVELY PINNING A RATHER EXPANSIVE OMEGA-TYPE RIDGE
IN PLACE FROM FLORIDA RIGHT ON UP THROUGH THE GREAT LAKES AND MUCH
OF EASTERN CANADA. THAT RIDGE SHOULD INCREASINGLY BECOME CUT OFF
OVER THE NORTHERN TIER FOR THE FIRST PART OF NEXT WEEK...AS THE
CLOSED LOW WANDERS RATHER AIMLESSLY SOMEWHERE TO OUR SOUTH (EXACT
POSITION STILL TO BE DETERMINED). AS THAT OCCURS...PREVAILING SOUTH
TO SOUTHEASTERLY LOW LEVEL FLOW WILL CONTINUE TO TRANSPORT SOME
RATHER MILD AIR NORTHWARD AS A PERSISTENT THERMAL RIDGE FEATURE
HOLDS INTACT ACROSS THE GREAT LAKES...FAVORING SOME MORE MUCH NEEDED
(AND LET`S FACE IT...MUCH DESERVED) WARM SPRINGTIME WEATHER FOR THE
NORTH WOODS.
LOOKING AT SOME SPECIFICS...STALLED FRONTAL BOUNDARY/INVERTED
TROUGH AXIS REMAINS PROGGED TO RESIDE ACROSS THE AREA THROUGH
FRIDAY...EFFECTIVELY SPLITTING THE STATE IN HALF. GIVEN YESTERDAY`S
HISTORY WITH THIS BOUNDARY COUPLED WITH AN INCREASINGLY DRIER
BOUNDARY LAYER LIKELY TO BE SHUNTED INTO THE REGION ON SLOWLY
BACKING SOUTHEAST FLOW REGIME...HAVE SOME DIFFICULTY BELIEVING WE
WILL BE ABLE TO MUSTER MUCH IN THE WAY OF ANY AFTERNOON CONVECTION.
WITH THAT SAID...THE CHANCE IS NOT COMPLETELY ZERO WITH A LIGHT
WIND/LAKE BREEZE REGIME FAVORING ENHANCED CONVERGENCE INTO THE
SLUGGISH SYNOPTIC BOUNDARY...AND AT LEAST DECENT HEATING ACROSS
NORTHEAST LOWER AND THE HIGHER TERRAIN.
THEREAFTER...JUST CANNOT JUSTIFY HAVING ANY POPS IN THE FORECAST
BEYOND FRIDAY EVENING...AS THE ENTIRE PATTERN SLOWLY RETROGRADES AND
THE BEST MOISTURE AXIS SLIPS WELL TO OUR WEST...ALL WHILE AN
INCREASINGLY DRY BOUNDARY LAYER MAKES AN APPEARANCE THROUGH THE
WEEKEND. LOOKING INTO NEXT WEEK...DEEPER MOISTURE AXIS SHOULD REMAIN
WELL TO OUR SOUTH AS THE UPPER LOW PINWHEELS THROUGH THE TENNESSEE
VALLEY (OR SOMEWHERE NEAR THERE)...WITH DRY EASTERLY FLOW PREVAILING
UP THIS WAY AND SUBSIDENCE ON THE NORTHERN FRINGE OF CLOSED LOW
FEATURE FAVORING LOTS OF SUNSHINE. HIGHS SHOULD RESPOND NICELY INTO
THE 60S TO MIDDLE 70S EACH AFTERNOON...COOLER NEAR THE LAKESHORES OF
COURSE WHERE LAKE BREEZE DEVELOPMENT IS LIKELY EACH DAY GIVEN A VERY
WEAK GRADIENT IN PLACE. OVERNIGHT LOWS ARE A BIT MORE TRICKY IN THIS
LIGHT GRADIENT SETUP...AS DAILY MIXING OF DEW POINTS INTO THE 40S
AND MAYBE 30S AND CLEAR SKIES SHOULD EASILY ALLOW READINGS TO DIP
QUICKLY AFTER SUNSET. SIMPLY PUT...THE WEATHER THROUGH NEXT WEEK
LOOKS DOWNRIGHT SPECTACULAR FOR ALL OF NORTHERN MICHIGAN...WITH WARM
SUNNY DAYS AND COOL COMFORTABLE NIGHTS. ENJOY!
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM EDT THU MAY 2 2013
SUMMARY: A STALLED FRONTAL SYSTEM WILL REMAIN JUST WEST OF
NORTHERN MICHIGAN THROUGH THE UPCOMING TAF PERIOD. THIS WILL BRING
THE CHANCE FOR SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS TO
MBL-TVC-PLN THROUGH 18Z FRIDAY.
RESTRICTIONS:VFR CONDITIONS ONGOING AND EXPECTED TO CONTINUE INTO
THIS EVENING. SOME SHRA/TSRA DEVELOPMENT POSSIBLE FROM TVC SOUTH
TO CAD THIS EVENING. WILL INCLUDE TEMPO MENTION AT MBL-TVC...BUT
REFRAIN FROM INCLUDING THUNDER AT THIS POINT GIVEN LACKLUSTER
INSTABILITY AND LOW CONFIDENCE IN THUNDER OCCURRENCE. OVERNIGHT...
PRIMARY CONCERN IS FOR THE DEVELOPMENT OF STRATUS OVER NORTHWEST
LOWER MICHIGAN. WILL INCLUDE THIS AFTER MIDNIGHT AT MBL/TVC...BUT
CONFIDENCE IS BELOW AVERAGE ON OCCURRENCE. ANY STRATUS SHOULD
QUICKLY MIX OUT FRIDAY MORNING WITH VFR CONDITIONS RESUMING THOUGH
THE END OF THE FORECAST PERIOD.
WINDS: CURRENTLY DOMINATED BY LOCAL LAKE BREEZES 10G15KTS THROUGH
LATE AFTERNOON WILL BECOME LIGHT/VARIABLE TONIGHT BEFORE MORE
NORTHEASTERLY WINDS AROUND 10KTS TAKE OVER FOR THE DAY ON FRIDAY
/EXCEPT AT APN WHERE A SOUTHEAST DIRECTION WILL CONTINUE/.
&&
.MARINE...
ISSUED AT 421 AM EDT THU MAY 2 2013
STATIONARY FRONT BISECTING LOWER MICHIGAN FROM NORTH TO SOUTH WILL
PRODUCE VERY DIFFERENT WIND CONDITIONS BETWEEN WHITEFISH BAY/LAKE
MICHIGAN AND LAKE HURON NEARSHORE ZONES...EVEN ON LAKE HURON
CONDITIONS WILL VARY QUITE A BIT. WESTERN ZONES WILL BE DEALING
WITH A STRONGER NORTHERLY GRADIENT ON THE COOLER SIDE OF THE
BOUNDARY...MAY PUSH SMALL CRAFT CONDITIONS WITHIN NORTHWEST LOWER
NEARSHORE ZONES. ON LAKE HURON...WINDS WILL VARY FROM A NORTHERLY
COMPONENT NORTH OF THUNDER BAY...AND A SOUTHERLY COMPONENT SOUTH
THOUGH BOTH AREAS WILL BE IMPACTED LOCALLY BY LAKE BREEZE COMPONENTS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ323-
344>346.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...DL
SHORT TERM...JPB
LONG TERM...DL
AVIATION...ARNOTT
MARINE...JPB
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
101 PM EDT THU MAY 2 2013
.SYNOPSIS...
ISSUED AT 421 AM EDT THU MAY 2 2013
A STRONG LOW PRESSURE SYSTEM WILL TAKE SHAPE ACROSS THE CENTRAL
PLAINS AND MID MISSISSIPPI VALLEY THROUGH THE WEEKEND...AS UPPER
LEVEL HIGH PRESSURE REMAINS PARKED ACROSS THE GREAT LAKES AND
NORTHEAST STATES. THIS WEATHER PATTERN WILL YIELD CONTINUED MILD
TEMPERATURES RIGHT ON THROUGH THE WEEKEND...WITH JUST A FEW SMALL
CHANCES FOR MAINLY AFTERNOON RAIN SHOWERS. DRY BUT CONTINUED WARM
WEATHER IS EXPECTED FOR MUCH OF NEXT WEEK...AS HIGH PRESSURE REMAINS
IN CONTROL ACROSS THE GREAT LAKES.
&&
.UPDATE...
ISSUED AT 100 PM EDT THU MAY 2 2013
CHANGES THIS HOUR: WILL CONTINUE TO EDGE THUNDERSTORM CHANCES WEST
GIVEN CURRENT SURFACE DEWPOINT ANALYSIS AS WELL AS EARLY AFTERNOON
VISIBLE SATELLITE IMAGERY SHOWING BEST CONGESTED CU IN THE HIGH
TERRAIN WEST AND SOUTH OF CADILLAC. COULD CERTAINLY SEE SOME
THUNDER IF CONVECTION CAN BREAK THE 50 J/KG CAPPING THAT REMAINS.
TEMPS A CHALLENGE WITH CAD-HTL-GOV LIKELY TO HIT 80...WITH
IMPRESSIVE DROP JUST TO THE NORTHWEST ACROSS THE SURFACE BOUNDARY.
REMAINDER OF FORECAST IN GOOD SHAPE.
UPDATE ISSUED AT 1018 AM EDT THU MAY 2 2013
CHANGES THIS HOUR: HAVE LOWERED HIGHS JUST A TAD AND DELAYED
SHOWER POTENTIAL TO PRIMARILY 18Z AND BEYOND. OTHERWISE...MINOR
CHANGES TO SKY TO ACCOUNT FOR STRATUS NEAR WHITEFISH POINT.
COOL FRONT SITS OVER THE CWA ATTM WITH 12Z APX RAOB SHOWING VERY
IMPRESSIVE...ALBEIT VERY SHALLOW SURFACE BASED INVERSION WITH T9
AT 19C AND +13C AT H8. BOUNDARY IS LIKELY TO MIX NORTH AND WEST
GIVEN AMPLE SURFACE BASED HEATING OVER NORTHERN LOWER HEADING INTO
EARLY AFTERNOON. SOME CAVEATS TO THIS...HOWEVER...INCLUDE
DEVELOPING MID CLOUDS FROM CAD TO CVX UNDER ISENTROPIC ASCENT AT
THIS LEVEL WHICH MAY HELP REINFORCE THE BOUNDARY IF IT CAN HOLD
TOGETHER. EXPECT THAT IT WILL NOT /OR MORE LIKELY THAT IT WILL
LIFT NORTH WITH TIME/...ALLOWING BOUNDARY TO PUSH TOWARDS THE
COAST OF NW LOWER. THIS SHOULD ALLOW TEMPS TO WORK TOWARDS
PREVIOUSLY FORECASTED HIGHS. CERTAINLY SOME TEMPERATURE BUST
POTENTIAL IN THE VICINITY OF WHERE THIS FRONT MIXES TO THIS
AFTERNOON /TVC-ACB-PLN/.
EARLY MORNING RAP SOUNDINGS HAVE A MUCH BETTER HANDLE ON MOISTURE
OVER ARRIVING AIRMASS FROM SOUTHEAST LOWER THAN THE NAM /12Z DTX
RAOB SHOWS 0C DEWPOINT AT H8...WITH 6C FROM THE NAM/. THE RESULT
OF THIS IS AN AFTERNOON CHARACTERIZED BY MORE MID 40S DEWPOINTS
THAN LOW 50S...REDUCING CONVECTIVE POTENTIAL. WILL THUS DELAY
POPS...BUT NOT PULL THEM AT THIS POINT...BUT AWAIT 12Z GUIDANCE
AND LATE MORNING OBSERVATIONAL TRENDS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 421 AM EDT THU MAY 2 2013
EARLY MORNING SURFACE ANALYSIS SHOWS A COLD/STATIONARY FRONT
EXTENDING FROM NORTHERN QUEBEC...SOUTHWEST ACROSS CENTRAL LOWER
MICHIGAN AND DOWN INTO NORTHWEST ILLINOIS/CENTRAL MISSOURI AND ON
INTO THE SOUTHERN PLAINS. THIS FRONT WAS ASSOCIATED WITH AN UPPER
LEVEL TROUGH ENCOMPASSING THE NATION`S MIDSECTION...AND ITS EASTWARD
PROGRESS WAS BEING IMPEDED BY A NARROW BUT HIGH AMPLITUDE BLOCKING
RIDGE OVER THE EASTERN THIRD OF THE NATION AND SUBSEQUENT TROUGHING
OVER THE WESTERN ATLANTIC. A 30-40 DEGREE TEMPERATURE CONTRAST
EXISTS ACROSS THE FRONT...WITH AN ELONGATED BAND OF POST-FRONTAL
RAIN AND SNOW FROM THE CENTRAL/SOUTHERN PLAINS NORTHWARD INTO THE
UPPER MISSISSIPPI VALLEY. CLOSER TO HOME...SCATTERED CONVECTION
DEVELOPED EARLIER ACROSS EASTERN UPPER MICHIGAN/NORTHERN LAKE
MICHIGAN...THE TAIL END OF A BAND OF SCATTERED SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHEAST ONTARIO. OTHERWISE SKIES ARE
CLEAR/PARTLY CLOUDY ACROSS NORTHERN LOWER.
STURDY RIDGE TO THE EAST WILL KEEP THINGS IN A HOLDING PATTERN
TODAY...STATIONARY FRONT WILL LIKELY WAVER A BIT DUE TO MIXING AND
LAKE BREEZE EFFECTS...BUT IS GOING TO ESSENTIALLY BISECT LOWER
MICHIGAN FROM NORTH TO SOUTH THROUGH THE SHORT TERM PERIOD. THIS
PRODUCES A MYRIAD OF FORECAST ISSUES FOR TODAY AND TONIGHT WITH
REGARD TO PRECIP CHANCES...TEMPERATURES...AND WINDS.
PRECIP ISSUES TODAY ARE PROBABLY GOING TO BE SIMILAR TO THOSE OF
WEDNESDAY...THAT IS WILL THERE BE ENOUGH MOISTURE TO GENERATE
INSTABILITY ALONG THE FRONT. FIRST...EXPECT THE FRONT TO MIX BACK
TO THE WEST...PROBABLY BACK TOWARD GLR-GOV-CAD THOUGH NORTHERN END
OF THE FRONT WILL PROBABLY BE DEFORMED IN AN EAST-WEST DIRECTION AS
LAKE HURON BREEZE RAMPS UP. THERE ARE INDICATIONS IN THE FORECAST
SOUNDINGS...PARTICULARLY THE GFS...OF STRATUS DEVELOPING ON THE COOL
SIDE OF THE FRONT VERY SHORTLY. THERE AREN`T ANY INDICATIONS OF
SUCH AS YET...SO WILL START OUT BY DOWNPLAYING THIS IDEA INITIALLY.
CAN SEE THE POSSIBILITY OF LOW CLOUDS DEVELOPING LATER THIS MORNING
AS THERMAL CONTRAST TIGHTENS...SUCH A SCENARIO IS MORE LIKELY OVER
THE COLD WATERS OF LAKE MICHIGAN AND PERHAPS SPILLING INTO ADJACENT
LAKESHORE AREAS OF NORTHWEST LOWER. SO WITH THE FRONT BACKING
TOWARD NORTHWEST LOWER...WILL PROBABLY TAKE DEW POINTS REMAINING IN
THE LOWER 50S TO GENERATE AROUND 500J/KG MLCAPE. TOOK ALL AFTERNOON
YESTERDAY TO GENERATE ONE SHOWER DURING THE EARLY EVENING...WONDER
IF WE`LL BE FACING THE SAME ISSUE TODAY. CURRENT THINKING IS THAT
IT IS CLOSE ENOUGH TO JUSTIFY CHANCE AFTERNOON POPS ACROSS MUCH OF
INTERIOR NORTHERN LOWER. ANOTHER POSSIBILITY FOR NORTHWEST LOWER IS
THAT UNSTABLE WARM SECTOR PARCELS ARE PULLED UP THE FRONTAL ZONE AND
CONVECT ON THE COOL SIDE OF THE BOUNDARY (ALONG/WEST OF US-131
CORRIDOR). SO SEVERAL POSSIBILITIES HERE. AS FOR TEMPERATURES
TODAY...AGAIN WILL VARY WIDELY DEPENDING ON LOCATION RELATIVE TO THE
FRONT AND LAKE BREEZE ACTIVITY. DON`T SEE WHY TEMPERATURES ON THE
WARM SIDE OF THE BOUNDARY WON`T MAKE ANOTHER RUN AT 80+ TODAY AS
CLOUD COVER SHOULD NOT BE MUCH OF AN ISSUE. RECORD HIGHS ARE A BIT
WARMER THAN YESTERDAY (APN 86/2001...HTL 88/1959...GLR 85/1959)...
AND WILL TAKE SOME TIME TO MIX THROUGH THE FRONTAL INVERSION SO
SHOULD BE A LITTLE SLOWER TEMPERATURE CLIMB THIS MORNING.
FOR TONIGHT...WILL BE DEALING BOTH WITH DEEPER MOISTURE NUDGING INTO
WESTERN PORTIONS OF THE FORECAST AREA AS WELL AS ELEVATED
INSTABILITY AND CONTINUE WARM ADVECTION. MUCH OF THE MOISTURE WILL
BE ACROSS THE WESTERN HALF OF THE FORECAST AREA AND THUS HIGHER
POPS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 421 AM EDT THU MAY 2 2013
SPRING LOOKS LIKE IT`S HERE TO STAY FOR THE FORESEEABLE FUTURE...
WITH ACTUALLY VERY FEW FORECAST ISSUES NOTED THROUGH THE WEEKEND AND
MAJORITY OF NEXT WORK WEEK. OVERALL UPPER PATTERN IS PROGGED BY ALL
AVAILABLE MEDIUM RANGE GUIDANCE TO REMAIN HEAVILY BLOCKED UP AS
CLOSED LOW DEVELOPMENT TAKES PLACE OVER THE MID MISSISSIPPI
VALLEY...WHILE ANOTHER CLOSED LOW MEANDER OVER THE WESTERN
ATLANTIC...EFFECTIVELY PINNING A RATHER EXPANSIVE OMEGA-TYPE RIDGE
IN PLACE FROM FLORIDA RIGHT ON UP THROUGH THE GREAT LAKES AND MUCH
OF EASTERN CANADA. THAT RIDGE SHOULD INCREASINGLY BECOME CUT OFF
OVER THE NORTHERN TIER FOR THE FIRST PART OF NEXT WEEK...AS THE
CLOSED LOW WANDERS RATHER AIMLESSLY SOMEWHERE TO OUR SOUTH (EXACT
POSITION STILL TO BE DETERMINED). AS THAT OCCURS...PREVAILING SOUTH
TO SOUTHEASTERLY LOW LEVEL FLOW WILL CONTINUE TO TRANSPORT SOME
RATHER MILD AIR NORTHWARD AS A PERSISTENT THERMAL RIDGE FEATURE
HOLDS INTACT ACROSS THE GREAT LAKES...FAVORING SOME MORE MUCH NEEDED
(AND LET`S FACE IT...MUCH DESERVED) WARM SPRINGTIME WEATHER FOR THE
NORTH WOODS.
LOOKING AT SOME SPECIFICS...STALLED FRONTAL BOUNDARY/INVERTED
TROUGH AXIS REMAINS PROGGED TO RESIDE ACROSS THE AREA THROUGH
FRIDAY...EFFECTIVELY SPLITTING THE STATE IN HALF. GIVEN YESTERDAY`S
HISTORY WITH THIS BOUNDARY COUPLED WITH AN INCREASINGLY DRIER
BOUNDARY LAYER LIKELY TO BE SHUNTED INTO THE REGION ON SLOWLY
BACKING SOUTHEAST FLOW REGIME...HAVE SOME DIFFICULTY BELIEVING WE
WILL BE ABLE TO MUSTER MUCH IN THE WAY OF ANY AFTERNOON CONVECTION.
WITH THAT SAID...THE CHANCE IS NOT COMPLETELY ZERO WITH A LIGHT
WIND/LAKE BREEZE REGIME FAVORING ENHANCED CONVERGENCE INTO THE
SLUGGISH SYNOPTIC BOUNDARY...AND AT LEAST DECENT HEATING ACROSS
NORTHEAST LOWER AND THE HIGHER TERRAIN.
THEREAFTER...JUST CANNOT JUSTIFY HAVING ANY POPS IN THE FORECAST
BEYOND FRIDAY EVENING...AS THE ENTIRE PATTERN SLOWLY RETROGRADES AND
THE BEST MOISTURE AXIS SLIPS WELL TO OUR WEST...ALL WHILE AN
INCREASINGLY DRY BOUNDARY LAYER MAKES AN APPEARANCE THROUGH THE
WEEKEND. LOOKING INTO NEXT WEEK...DEEPER MOISTURE AXIS SHOULD REMAIN
WELL TO OUR SOUTH AS THE UPPER LOW PINWHEELS THROUGH THE TENNESSEE
VALLEY (OR SOMEWHERE NEAR THERE)...WITH DRY EASTERLY FLOW PREVAILING
UP THIS WAY AND SUBSIDENCE ON THE NORTHERN FRINGE OF CLOSED LOW
FEATURE FAVORING LOTS OF SUNSHINE. HIGHS SHOULD RESPOND NICELY INTO
THE 60S TO MIDDLE 70S EACH AFTERNOON...COOLER NEAR THE LAKESHORES OF
COURSE WHERE LAKE BREEZE DEVELOPMENT IS LIKELY EACH DAY GIVEN A VERY
WEAK GRADIENT IN PLACE. OVERNIGHT LOWS ARE A BIT MORE TRICKY IN THIS
LIGHT GRADIENT SETUP...AS DAILY MIXING OF DEW POINTS INTO THE 40S
AND MAYBE 30S AND CLEAR SKIES SHOULD EASILY ALLOW READINGS TO DIP
QUICKLY AFTER SUNSET. SIMPLY PUT...THE WEATHER THROUGH NEXT WEEK
LOOKS DOWNRIGHT SPECTACULAR FOR ALL OF NORTHERN MICHIGAN...WITH WARM
SUNNY DAYS AND COOL COMFORTABLE NIGHTS. ENJOY!
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1250 AM EDT THU MAY 2 2013
VFR. -SHRA POSSIBLE TO LIKELY THURSDAY AFTERNOON/EVENING MBL/TVC/PLN.
STALLING FRONT A BIT SE OF APN/HTL TONIGHT. SOME MID CLOUDS HAVE
DEVELOPED BEHIND THE FRONT (CIGS 6-10K FT). THIS DECK WILL BE
SOMEWHAT SPORADIC UNTIL THU AFTERNOON...WHEN CLOUDS WILL THICKEN
(ESPECIALLY IN NW LOWER AND THE STRAITS REGION). SOME -SHRA WILL
DEVELOP FROM THIS DECK IN THE AFTERNOON AND EVENING. MBL/TVC/PLN ALL
HAVE SOME MIX OF -SHRA AND/OR VCSH IN THE TAF IN THE AFTERNOON/
EVENING. WILL KEEP CONDITIONS VFR FOR NOW...THOUGH ANY PLACE THAT
GETS DECENTLY WET LATE THURSDAY WILL BE AT AN ENHANCED RISK TO SEE
FOG/STRATUS FORM THURSDAY NIGHT.
NORTHERLY BREEZES WILL CONTINUE AT MBL/TVC/PLN...WITH AN EAST WIND
FOR MOST OF THE FORECAST AT APN.
&&
.MARINE...
ISSUED AT 421 AM EDT THU MAY 2 2013
STATIONARY FRONT BISECTING LOWER MICHIGAN FROM NORTH TO SOUTH WILL
PRODUCE VERY DIFFERENT WIND CONDITIONS BETWEEN WHITEFISH BAY/LAKE
MICHIGAN AND LAKE HURON NEARSHORE ZONES...EVEN ON LAKE HURON
CONDITIONS WILL VARY QUITE A BIT. WESTERN ZONES WILL BE DEALING
WITH A STRONGER NORTHERLY GRADIENT ON THE COOLER SIDE OF THE
BOUNDARY...MAY PUSH SMALL CRAFT CONDITIONS WITHIN NORTHWEST LOWER
NEARSHORE ZONES. ON LAKE HURON...WINDS WILL VARY FROM A NORTHERLY
COMPONENT NORTH OF THUNDER BAY...AND A SOUTHERLY COMPONENT SOUTH
THOUGH BOTH AREAS WILL BE IMPACTED LOCALLY BY LAKE BREEZE COMPONENTS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ323-
344>346.
LS...NONE.
&&
$$
UPDATE...ARNOTT
SYNOPSIS...DL
SHORT TERM...JPB
LONG TERM...DL
AVIATION...JZ
MARINE...JPB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
630 PM EDT THU MAY 2 2013
.SYNOPSIS...
INTERVALS OF LIGHT RAIN AND DRIZZLE WILL CONTINUE TO MOVE ONSHORE
FROM TIME TO TIME THROUGH SATURDAY. A MORE SIGNIFICANT STORM
SYSTEM WILL AFFECT THE REGION NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 615 PM THURSDAY...THIS UPDATE MAINLY CONCERNED WITH PCPN
COVERAGE THIS EVENING AND OVERNIGHT. BASED ON LATEST KLTX AND
SURROUNDING 88DS...AND THE LATEST HRRR OUTPUT...PCPN IN THE FORM
OF STRATIFORM R- AND L- TO MOVE FROM ENE TO WSW ACROSS THE FA
EARLY INTO THE MID-EVENING HOURS. WILL BASICALLY DROP POPS BELOW
15 PERCENT ACROSS INLAND LOCATIONS OVERNIGHT...BUT KEEP SLIGHT
CHANCE ALONG THE IMMEDIATE COAST FOR ANY ONSHORE MOVEMENT. NO
CHANGES TO OVERNIGHT TEMPS AT THIS POINT.
PREVIOUS DISCUSSION.............................................
AS OF 230 PM THURSDAY...MOIST NORTHEASTERLY FLOW WILL CONTINUE
THROUGH THE NEAR TERM AS HIGH PRESSURE PRESSES DOWN FROM THE
NORTH. LOW LEVEL CONVERGENCE ALONG THE COAST ALLOWING PATCHES OF
LIGHT RAIN AND DRIZZLE TO FORM AND MOVE INLAND. THIS PATTERN WILL
CONTINUE FOR THE REMAINDER OF THE AFTERNOON. NOT MUCH CHANGES FOR
TONIGHT OTHER THAN SOME ADDITIONAL DRYING AT THE MID LEVELS.
HOWEVER...AS PRESENT PRECIPITATION REGIME IS PRIMARILY A STRATUS
EVENT...WILL BE KEEPING IN THE CHANCE FOR ADDITIONAL LIGHT RAIN
AND DRIZZLE INTO THE NIGHT-TIME HOURS...WITH THE BEST CHANCES
ALONG THE COAST. A CONSENSUS OF GUIDANCE GIVES US OVERNIGHT
TEMPERATURES NOT FAR FROM CLIMO...MID 50S INLAND AND UPPER 50S
CLOSER TO THE COAST.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...MAIN FORECAST CHALLENGE IS THE POSSIBILITY
OF THE INTERVALS OF NUISANCE RAIN/DRIZZLE CONTINUING FOR THE NEXT
COUPLE OF DAYS. ALTHOUGH THERMAL PROFILES CONTINUE TO DRY
OUT...THE FACT THAT THE NATURE OF THE SHOWERS HAS BEEN AND IS VERY
SHALLOW. THIS ALMOST GOES WITHOUT SAYING WITH DRIZZLE. THE
GFS...NAM AS WELL AS SREF PLUME DIAGRAMS SHOW SMALL AREAS OF QPF
INDICATIVE OF THIS ACTIVITY CONTINUING THROUGH
SATURDAY...THEREFORE...I HAVE ADDED THIS TO THE FORECAST. TIMING
IS DIFFICULT BUT LEANED TOWARD THE NAM TO SHOW AN INCREMENTAL
DIFFERENCE WITH A SLIGHT INCREASE BOTH FRIDAY AND SATURDAY
MORNINGS. ONLY SMALL CHANGES TO TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...CLIMATOLOGICALLY UNUSUAL SETUP THROUGH MOST OF
THE PERIOD MAKING FOR SOME INTERESTING AND CHALLENGING FORECASTS.
DEEP CUTOFF UPPER LOW WILL APPROACH AND EVENTUALLY TRAVERSE THE
CAROLINAS...WHICH IS MUCH MORE TYPICAL OF WINTER OR MUCH EARLIER IN
THE SPRING. IT IS MORE THE ISOLATION FROM THE FLOW OF THIS FEATURE
RATHER THAN ITS UNUSUAL TIMING THAT MAKES THE FORECAST CHALLENGING
SINCE SUCH FEATURES ARE USUALLY POORLY HANDLED BY MODEL GUIDANCE.
THAT SAID THE MODELS HAVE COME INTO PRETTY GOOD AGREEMENT WITH THE
EVOLUTION OF THE PATTERN. THERE WILL STILL BE SOME FUTURE
REFINEMENTS IN THE TIMING POSSIBLE AND THE WEATHER ITSELF WILL BE
QUITE COMPLEX AS WE SHOULD GO THROUGH SOME DISTINCT REGIME CHANGES
THROUGH THE PERIOD. SUNDAY APPEARS TO BE THE LAST DAY IN THE
PRE FRONTAL FLOW AHEAD OF THE UPPER LOW. MOISTURE WILL BE RAPIDLY ON
THE RISE ESP ACCORDING TO THE RELATIVELY FASTER GFS. BEST FORCING IN
THE FORM OF MID LEVEL JETTING AND HEIGHT FALLS COME EITHER LATE
SUNDAY OR SUNDAY NIGHT INTO MONDAY AGAIN DEPENDING ON MODEL SOLN.
RAINFALL CHANCES AND QPF POTENTIAL ARE STARTING TO LOOK PRETTY GOOD
WITH SUCH STRONG FORCING AND DEEP ATLANTIC MOISTURE EXPECTED. THEN
THE SYNOPTIC SCALE DRY SLOT WILL MOVE ACROSS THE AREA SHUTTING OFF
THE RAINFALL FOR ABOUT A PERIOD. WE WILL THEN MOVE INTO A VERY
CONVECTIVE REGIME AS THE COLD POOL ALOFT CRAWLS ACROSS THE REGION.
RIGHT NOW BEST ESTIMATE IS THIS IS TUESDAY...WHICH COULD BE A BUSY
DAY WITH A RADAR SCOPE FULL OF SMALL HAIL PRODUCING SHALLOW TSTMS.
RAIN CHANCES WILL BE SMALLER FOR THE REMAINDER OF THE PERIOD AS THE
SLOW MOVING SYSTEM COULD STILL PLAGUE THE COASTAL CAROLINAS WITH
WRAP-AROUND MOISTURE.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...MVFR WITH AREAS OF VFR WILL CONTINUE THROUGH THE
EVENING HOURS DUE TO LOWERED CIGS. INTO THE OVERNIGHT
HOURS...MVFR RETURNS WITH POSSIBLE IFR DUE TO LOWERED CIGS ONCE
AGAIN.
ISOLATED SHOWERS CONTINUE TO MOVE ONSHORE THIS AFTERNOON WITH
WIDESPREAD MVFR...AND AREAS OF VFR...AND EAST-NORTHEAST WINDS AOB
15 KTS. INTO THE LATER AFTERNOON HOURS COULD SEE SOME MORE AREAS
IMPROVE TO VFR...INITIALLY AT THE COAST AND THEN WESTWARD TO THE
INLAND SITES AS DRIER AIR USHERS INTO THE AREA. FCST SOUNDINGS AND
TIME-HEIGHT ANALYSIS ARE IN DECENT AGREEMENT FOR THE RETURN OF
LOWERED CIGS LATE OVERNIGHT INTO THE MORNING HOURS. ANTICIPATE
MVFR...BUT CANNOT RULE OUT IFR. CONDITIONS WILL GRADUALLY IMPROVE
TO VFR AGAIN TOWARDS THE END OF THE VALID PERIOD.
AS FOR WINDS...EXPECT EAST-NORTHEAST WINDS 12-15 KTS TO
CONTINUE...WITH GUSTS UP TO 25 KTS POSSIBLE THIS AFTERNOON. GUSTS
WILL SUBSIDE INTO THE EVENING HOURS...BUT ANTICIPATE EAST WINDS TO
CONTINUE AOB 12 KTS THROUGH THE REMAINDER OF THE VALID PERIOD.
EXTENDED OUTLOOK...SLIGHT CHANCE OF SHOWERS THURSDAY WITH BREEZY
CONDITIONS THROUGH FRIDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 615 PM THURSDAY...PERSISTENCE THE WORD HERE...CURRENT WIND
AND SEA CONDITIONS REMAIN WITHIN THE CONSTRAINTS OF THE CURRENT
FORECAST. SEE NO CHANGES NEEDED AT THIS TIME. THE NEXT UPDATE MAY
WARRANT THE EXTENSION OF THE SCA OUT FURTHER IN TIME...IF MODEL
CONSENSUS REMAINS UNCHANGED.
PREVIOUS DISCUSSION.............................................
AS OF 230 PM THURSDAY...HIGH PRESSURE PRESSING DOWN FROM THE NORTH
WILL KEEP UP A STEADY NORTHEASTERLY FLOW IN THE PRESENT 15 TO 20
KT RANGE. SEAS WILL WILL NOT STRAY FROM PRESENT 4 TO 7 FT
RANGE...SO EXPECT TO KEEP SMALL CRAFT ADVISORY IN EFFECT THROUGH
THE NEAR TERM.
ADVISORY FLAGS REMAIN FLAPPING ACROSS ALL MARINE ZONES FOR 25 KT
GUSTS AND 4-7 FOOT SEAS. STRONG HIGH PRESSURE NORTH OF THE WATERS
WILL CONTINUE TO PRESS SOUTHWARD. LOWER PRESSURE ACROSS FLORIDA
INTERACTING WITH THE HIGH WILL KEEP THE MSLP GRADIENT TIGHT WITH
BLUSTERY NE-E WINDS EXPECTED THROUGH TONIGHT. E WAVES OF 4-7 FEET
WILL RUN IN WAVE INTERVALS OF 6-8 SECONDS RESULTING IN STEEP-FACED
AND TREACHEROUS WAVES. ISOLATED SHOWERS WILL TRACK FROM EAST TO
WEST AND ONSHORE TODAY BUT NO TSTMS OR WIDESPREAD RESTRICTIONS TO
VISIBILITY ARE ANTICIPATED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...PERSISTENT NORTHEAST FLOW CONTINUES THROUGH
THE PERIOD. THERE MAY BE A LITTLE VEERING VERY LATE IN THE PERIOD
TO MORE OF A EASTERLY FLOW BUT OVERALL...THE NE FLOW WILL BE THE
STORY. STRONGEST WINDS WILL OCCUR FRIDAY WITH A FEW AREAS ACROSS
THE OUTER WATERS POSSIBLY EXCEEDING 25 KNOTS. FOR NOW THINK THESE
SPEEDS WILL BE LIMITED IN DURATION TO KEEP GALE CONSIDERATION IN
CHECK. SEAS WILL REMAIN RUGGED THROUGH THE PERIOD AND WILL ALMOST
CERTAINLY SEE THE SMALL CRAFT ADVISORY CONTINUE.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...FAIRLY COMPLEX AND ACTIVE WEATHER EXPECTED FOR
MOST OF THE PERIOD ESPECIALLY EARLY ON. A DEEPLY CUTOFF UPPER SYSTEM
WILL APPROACH FROM THE WEST ON SUNDAY WITH A COLD FRONT ALONG ITS
LEADING EDGE. ONSHORE/EASTERLY FLOW WILL GET PINCHED BY THIS
APPROACHING BOUNDARY AS HIGH PRESSURE NOSED INTO THE CAROLINAS TRIES
TO HOLD ITS GROUND. AT SOME POINT THERE SHOULD BE SOME PRETTY SHARP
VEERING AS THE HIGH LOSES GROUND TO THE APPROACHING FRONT...AND THIS
IS PROBABLY THE MOST UNCERTAIN PART OF THE FORECAST. SOUTHERLY FLOW
SHOULD OVERSPREAD BY MONDAY WITH ADDITIONAL VEERING DUE TO THE
CYCLONIC CURVATURE OF THE ISOBARS COMING ACROSS THE CAROLINAS MONDAY
NIGHT INTO TUESDAY. ALL OF THE CHANGING OF THE WIND DIRECTION
THROUGH THE PERIOD SHOULD KEEP WAVE FACES RATHER STEEP AND PERIODS
SHORT MAKING FOR CHOPPY CONDITIONS. WHETHER OR NOT ANY CAUTIONARY
HEADLINES OR EVEN ADVISORIES ARE NEEDED TO TO WAVE HEIGHTS IS VERY
UNCERTAIN BUT WIND SPEEDS WILL REMAIN SHY OF EITHER.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...DCH/REK
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
629 PM EDT THU MAY 2 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH THE WEEKEND THEN
WEAKEN SOME EARLY NEXT WEEK. LOW PRESSURE EXTENDING UP THE
MISSISSIPPI VALLEY TO LAKE MICHIGAN WILL STAY STATIONARY INTO
SATURDAY THEN SLOWLY MOVE EAST THROUGH THE LOWER TENNESSEE VALLEY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LITTLE CHANGE TO CURRENT FORECAST AT THIS TIME. LATEST HRRR MODEL
INDICATES A BIT OF CONVECTION DEVELOPING LATER TONIGHT OVER THE
EXTREME WEST. HOWEVER...WITH AIR MASS OVER THE REGION BEING SO
DRY...WE MAY JUST ESCAPE WITH A FEW SPRINKLES. OTHERWISE...THE
REST OF THE FORECAST AREA WILL REMAIN DRY AND QUITE PLEASANT TONIGHT.
LAKE BREEZE DROPPED TEMPERATURES INTO THE UPPER 50S ALONG THE
IMMEDIATE LAKESHORE AND LOWER TO MIDDLE 60S A BIT FURTHER INLAND.
EXPECTING LAND BREEZE TO DEVELOP AND BRING AND END TO THE COOLER
TEMPERATURES. WE SHOULD SEE A RISE IN THE TEMPERATURES THIS
EVENING BEFORE FALLING OFF AGAIN. TEMPERATURES ACROSS THE REST OF
THE AREA WILL SEE A GRADUAL DECLINE AFTER SUNSET.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
UPPER LEVEL TROUGH CLOSES OFF OVER THE SOUTHERN PLAINS ON FRIDAY
THEN SLOWLY DRIFTS EASTWARD OVER THE WEEKEND. HIGH CLOUD WILL
CONTINUE TO SPREAD NORTH AROUND THE UPPER LOW AND EXPECT PERIODS OF
SUN AND CLOUD OVER THE NEXT COUPLE DAYS. LOW LEVEL FLOW MAINTAINS AN
EASTERLY WIND COMPONENT BETWEEN HIGH PRESSURE OVER NEW ENGLAND AND
THE LOW TO THE SOUTH. THIS WILL CAUSE LOW LEVELS TO ACTUALLY UNDERGO
SOME DRYING BY SATURDAY AND 12Z MODELS MAINTAIN A DRY FORECAST
THROUGH THE WEEKEND. MODELS HAVE STRUGGLED WITH THE TRACK OF THE LOW
OVER THE LAST COUPLE DAYS BUT HAVE COME INTO FAIRLY GOOD AGREEMENT.
TEMPERATURES ON FRIDAY WILL BE SIMILAR TO TODAY THEN SETTLE BACK
DOWN INTO THE LOWER 70S AS THE AIRMASS COOLS OVER THE WEEKEND.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
IT APPEARS THAT MOST IF NOT ALL OF THE LONG TERM PERIOD WILL BE
DRY. THERE COULD BE A FEW SHOWERS IN THE SOUTH MONDAY AND TUESDAY
AS THE UPPER LOW PASSES TO THE SOUTH OF THE REGION. CHANCES ARE
REALLY SMALL AND NO MORE THAN A HUNDREDTH OR TWO OF RAINFALL IS
EXPECTED EVEN IF SHOWERS DEVELOP. HIGH PRESSURE WILL RETURN
WEDNESDAY AND THURSDAY WITH DRY WEATHER EXPECTED. TEMPERATURES WILL
AVERAGE ABOUT 5 DEGREES ABOVE NORMAL DURING THE PERIOD WITH HIGHS
TUESDAY THROUGH THURSDAY REACHING THE 70S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
QUIET WEATHER WILL CONTINUE. THERE COULD BE A BRIEF INCREASE IN
CLOUDS IN THE FAR WEST LATE TONIGHT. THE REST OF THE AREA WILL SEE
JUST A FEW HIGH CLOUDS. SE TO E FLOW WILL CONTINUE. A LAKE BREEZE
HAS ALREADY DEVELOPED AT KERI. DO NOT THINK A LAKE BREEZE WILL
REACH KCLE.
.OUTLOOK...NON-VFR CONDITIONS POSSIBLE BY MONDAY.
&&
.MARINE...
A FAIRLY PERSISTENT PATTERN WILL CONTINUE OVER LAKE ERIE INTO THE
WEEKEND. THE RIDGE WILL REMAIN OVER THE REGION AS AN UPPER LEVEL
LOW REMAINS TO THE WEST. A SOUTHEAST FLOW WILL REMAIN OVER THE LAKE
WITH AN ONSHORE FLOW DEVELOPING IN THE AFTERNOON. THE MODELS SHOW
THE UPPER LEVEL LOW DRIFTING SOUTH OF THE OHIO VALLEY FOR THE
BEGINNING OF NEXT WEEK. THIS WILL ALLOW THE WINDS TO SHIFT MORE
FROM THE NORTHEAST AND EVENTUALLY NORTHERLY BY LATE NEXT WEEK. THE
FLOW SHOULD REMAIN FAIRLY LIGHT AND REMAIN 15 KNOTS OR LESS THROUGH
MOST OF THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...LOMBARDY
SHORT TERM...KEC
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...GARNET
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1133 AM CDT THU MAY 2 2013
.UPDATE...
GUSTY NORTHEAST WINDS WILL CONTINUE THROUGH THE AFTERNOON. THEY ARE
IN RESPONSE TO TIGHT SURFACE PRESSURE GRADIENT WITH STRENGTHENING
LOW OVER CENTRAL IL AND ALSO SOUTHERN MI...AND HIGH PRESSURE
BUILDING INTO THE NORTHERN PLAINS. WINDS ARE NORTHERLY UP TO AROUND
2000 FEET AND SOUTHERLY JUST ABOVE THAT LEVEL.
SCATTERED THUNDERSTORMS FIRING UP OVER CENTRAL IL WHERE THERE IS
ONLY A SHALLOW CAP ARE MOVING NORTHWARD INTO SOUTHERN WI LATE THIS
MORNING. THEY ARE ELEVATED IN THE WARM LAYER AND TAPPING INTO SOME
ELEVATED CAPE UP TO 300 J/KG...SO EXPECT ISOLATED THUNDER AND BRIEF
MODERATE DOWNPOURS WITH THIS SCATTERED CONVECTION AS IT ROLLS
THROUGH AREAS OF SOUTHERN WI THIS AFTERNOON. SMALL HAIL IS NOT OUT
OF THE QUESTION WITH THIS ELEVATED CONVECTION.
RAIN CHANCES INCREASE ACROSS ALL OF SOUTHERN WI THIS EVENING AS A
500MB SHORTWAVE COINCIDES WITH WEAK WARM AIR ADVECTION.
&&
.AVIATION/18Z TAFS/...
MAIN UNCERTAINTY IS WHEN PRECIPITATION WILL ARRIVE AND WHEN WILL IFR
CEILINGS FINALLY DEVELOP.
GUSTY NORTHEAST WINDS WILL CONTINUE THROUGH THE AFTERNOON. THEY ARE
IN RESPONSE TO TIGHT SURFACE PRESSURE GRADIENT WITH STRENGTHENING
LOW OVER CENTRAL IL AND ALSO SOUTHERN MI...AND HIGH PRESSURE
BUILDING INTO THE NORTHERN PLAINS. WINDS ARE NORTHERLY UP TO AROUND
2000 FEET AND SOUTHERLY JUST ABOVE THAT LEVEL.
SCATTERED THUNDERSTORMS FIRING UP OVER CENTRAL IL WHERE THERE IS
ONLY A SHALLOW CAP ARE MOVING NORTHWARD INTO SOUTHERN WI LATE THIS
MORNING. THEY ARE ELEVATED IN THE WARM LAYER AND TAPPING INTO SOME
ELEVATED CAPE UP TO 300 J/KG...SO EXPECT ISOLATED THUNDER AND BRIEF
MODERATE DOWNPOURS WITH THIS SCATTERED CONVECTION AS IT ROLLS
THROUGH AREAS OF SOUTHERN WI THIS AFTERNOON. SMALL HAIL IS NOT
OUT OF THE QUESTION WITH THIS CONVECTION THIS AFTERNOON.
VFR CEILINGS SHOULD GRADUALLY LOWER AS CLOUDS INCREASE TODAY.
RAIN IS THEN SHOWN BY MODELS TO GROW IN COVERAGE DURING THE EVENING.
COMBINED WITH DIURNAL COOLING...STRATUS FORMATION SHOULD COMMENCE
WITH IFR TO PERHAPS LIFR CEILINGS.
&&
.PREV DISCUSSION... /ISSUED 336 AM CDT THU MAY 2 2013/
TODAY...FORECAST CONFIDENCE...MEDIUM
MAIN ISSUE IS WHEN TO RAMP UP THE POPS. AS BOTTOM OF TROUGH CREATES
100 METER 500 MB 12 HOUR HEIGHT FALLS IN KS...MAIN BAROCLINIC ZONE
ONLY DRIFTS EAST DURING THE DAY.
CURRENT BAND OF PRECIPITATION IS SITUATED IN WARM ADVECTION AND
FRONTOGENESIS IN 700-600 MB LAYER. NOT MUCH PRECIPITATION FALLING
OUTSIDE OF THAT ZONE...WITH EXCEPTION OF A COUPLE OF SHOWERS AND
THUNDERSTORMS IN MISSOURI. SOME OF THE MODEL GUIDANCE WAY OVERDONE
ON QPF OVERNIGHT FROM MISSOURI INTO MICHIGAN. GFS IS WORST
OFFENDER.
PRECIPITATION CHANCES TODAY ARE MAINLY TIED TO CONVECTION FORMING IN
WEAK WARM ADVECTION ZONE TO EAST OF MAIN POST FRONTAL PRECIPITATION
SHIELD. IT WOULD FORM IN WARM SECTOR OVER ILLINOIS AND THEN BECOME
ELEVATED OVER SHALLOW LOW LEVEL COLD AIR IN SOUTHERN WISCONSIN.
MOST OF THE GUIDANCE PRODUCES CONVECTION INCLUDING THE 4KM NMM AND
ARW CORES. HOWEVER...THE COVERAGE MAY NOT BE SUFFICIENT TO WARRANT
CATEGORICAL POPS. LATEST HRRR MODEL HAS NOTHING HAPPENING THROUGH
20Z...BUT THERE ARE A FEW SHOWERS FROM 15-18Z ON LOCAL WSWRF 4KM ARW
CORE. WILL TRY AND KEEP POPS HIGH THIS AFTERNOON FOR NOW...BUT MAY
HAVE TO CONSIDER CHOPPING THEM DOWN A BIT AT 12Z SHORT TERM UPDATE
BEFORE HEADING HOME.
CLOUDS AND NORTHEAST WINDS WILL MAKE IT FEEL MUCH DIFFERENT TODAY
THAN PAST COUPLE OF DAYS. 40S MUCH OF THE DAY NEAR THE
LAKE...BASICALLY CUTTING THE TEMPERATURE IN HALF FROM PAST COUPLE OF
DAYS.
TONIGHT...FORECAST CONFIDENCE...MEDIUM
CLOSED LOW BECOMES ESTABLISHED OVER KANSAS WITH FLOW GOING FROM
SOUTHWEST TO SOUTHERLY ALOFT OVER WISCONSIN. GRADUAL 40 METER
HEIGHT FALLS OVERNIGHT. MOST OF THE MODELS HAVE LIGHT PRECIPITATION
DURING THE NIGHT IN WEAK WARM ADVECTION REGIME. STRONGEST FORCING
SHOWN TO STAY CLOSER TO UPPER LOW FROM IOWA INTO MISSOURI.
BOTH NAM AND GFS SHOW SURFACE TEMPERATURES FALLING CLOSE TO FREEZING
IN FAR NORTHWEST AT SURFACE...BUT THAT AIR IS PRETTY SHALLOW. THERE
IS A NON-ZERO PROBABILITY OF FREEZING RAIN OUT WEST...BUT SREF
PROBABILITIES OF 60 TO 80% SEEM WAY TOO HIGH. LOOKS LIKE
TEMPERATURES GET DOWN TO 33 TO 35F WITH RAIN AND DEW POINTS AROUND
FREEZING...SO LITTLE HELP FROM WET BULB COOLING. FOR NOW WILL LEAVE
IT OUT.
FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE...MEDIUM
WILL BE EVEN COOLER FRIDAY...WITH SHOWERS EXPECTED ACROSS THE
FORECAST AREA AS LOW PRESSURE TO THE SOUTHWEST DRIFTS EASTWARD.
EAST WINDS WILL LIKELY KEEP TEMPS IN THE 40S NEAR THE LAKE...WITH
HIGHS STRUGGLING TO AROUND 50 ELSEWHERE.
SHOWER CHANCES WILL CONTINUE SATURDAY AS THE LOW REMAINS IN THE
REGION...THE BEST CHANCE IN THE SOUTHWEST. LOOKS LIKE SOME MILDER
TEMPS MAY SNEAK BACK INTO THE AREA...WITH HIGHS EXPECTED TO
RECOVER TO AROUND NORMAL MOST PLACES. WILL LIKELY SEE COOLER TEMPS
NEAR THE LAKE UNDER ONSHORE WINDS.
SHOULD BE MAINLY DRY SUNDAY...BUT KEPT SOME LOW POPS IN AS THE LOW
CONTINUES TO SLOWLY PULL AWAY. NEAR AVERAGE TEMPS SHOULD CONTINUE.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
UPPER LOW WILL FINALLY BE OUT OF THE AREA BY MONDAY...WITH MODELS
TRENDING DRIER FOR EARLY NEXT WEEK. THERE IS INCREASING AGREEMENT
THAT HIGH PRESSURE MAY BRING PLEASANT WEATHER THROUGH AT LEAST
TUESDAY...SO LOWERED POPS ACCORDINGLY. MAY BE ABLE TO GET RID OF
THE POPS ALTOGETHER SOON IF THIS TREND CONTINUES. SHOULD SEE
WARMING TEMPS...POSSIBLY HITTING THE 70 DEGREE MARK BY TUESDAY.
AVIATION/12Z TAFS/...
MAIN UNCERTAINTY IS WHEN PRECIPITATION WILL ARRIVE AND WHEN WILL IFR
CEILINGS FINALLY DEVELOP.
VFR CEILINGS SHOULD GRADUALLY LOWER AS CLOUDS INCREASE TODAY. MANY
OF THE MODELS DEVELOP CONVECTIVE SHOWERS OVER ILLINOIS IN THE WARM
SECTOR AND THEN MOVE THEM NORTH INTO WISCONSIN DURING THE
AFTERNOON. RAIN IS THEN SHOWN TO GROW IN COVERAGE DURING THE
EVENING. COMBINED WITH DIURNAL COOLING...STRATUS FORMATION SHOULD
COMMENCE WITH IFR TO PERHAPS LIFR CEILINGS.
CURRENT GUSTY NORTHEAST SHOULD RELAX A BIT BUT STILL DECENT CHANCE
OF 20-25 KNOT GUSTS TODAY AND TONIGHT.
MARINE...
WINDS GUSTED TO NEAR GALE FORCE FOR A TIME BUT SHOULD SETTLE INTO
STEADY SMALL CRAFT ADVISORY LEVELS FROM NNE AND CONTINUE THROUGH
FRIDAY. FAVORABLE FETCH AND SLOW PROCESS OF SUBSIDING WAVES MAY
REQUIRE SCA TO BE EXTENDED INTO FRIDAY EVENING BUT PLENTY OF TIME TO
EVALUATE THAT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT FRIDAY FOR LMZ643>646.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...CRAVEN
FRIDAY THROUGH WEDNESDAY...DDV