Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/15/15
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1109 PM MDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 918 PM MDT TUE MAY 12 2015
UPDATED FORECAST TO REFINE TIMING OF POPS THROUGH THE OVERNIGHT
HOURS AND INTO WEDNESDAY. SHOWERS AND THUNDERSTORMS HAVE
DECREASED ACROSS MOST OF THE FORECAST AREA...THOUGH STILL CONTINUE
ALONG THE CONTDVD. LATEST HRRR AND RAP SHOW PRECIPITATION WANING
ACROSS THE SE MTS...VALLEYS AND I-25 CORRIDOR THROUGH 08Z...THEN
INCREASING AGAIN AS FORCING FROM THE UPPER TROF ACROSS THE DESERT
SOUTHWEST STARTS APPROACHES THE REGION. THESE WILL THEN START TO
SPREAD INTO THE SOUTHERN I-25 CORRIDOR AFTER 12Z...THEN INTO ALL
OF THE SOUTHEAST PLAINS BY WED AFTERNOON AS THE UPPER TROF LIFTS
INTO THE TX/OK PANHANDLES AND SE CO BY 00Z. NICE WAA/OVERRUNNING
PATTERN SETS UP ACROSS THE FAR SOUTHEAST PLAINS...AND ALTHOUGH QPF
LOOKS HEAVIEST TO OUR SOUTH AND EAST OF THE AREA...THE SOUTHEAST
PLAINS SHOULD SEE A BOUT OF MODERATE RAINFALL WEDNESDAY
AFTERNOON...PARTICULARLY TO THE EAST OF LHX. ADJUSTED POPS
SLIGHTLY FOR TIMING. NOT A LOT OF CAPE OR SHEAR TO WORK WITH...SO
MAIN THREAT TOMORROW WILL BE THE POTENTIAL FOR LOCALIZED FLASH
FLOODING ACROSS THE SOUTHEAST PLAINS WITH ANY EMBEDDED CONVECTIVE
ELEMENTS...ESPECIALLY SINCE SOIL IS ALREADY SATURATED AND RIVER IS
RUNNING HIGH. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 337 PM MDT TUE MAY 12 2015
CURRENTLY...A DEEP UPPER TROUGH OF LOW PRESSURE OVER THE WEST COAST
WAS DRAWING MOISTURE UP ACROSS OLD MEXICO...AZ AND NM INTO THE 4
CORNERS. MID AND HIGH LEVEL MOISTURE WAS STREAMING INTO WESTERN
COLORADO...AND CLOUD COVER WAS ON THE INCREASE ACROSS THE WESTERN
HALF OF THE STATE THIS AFTN. A GOOD AMOUNT OF LTG ACTIVITY WAS
EVIDENT IN NM...BUT AS OF 3 PM NO CONVECTION YET ACROSS THE CWA.
STRONG SOUTHERLY SFC WINDS HAVE HELPED TO WARM TEMPS INTO THE MID
60S TO MID 70S ACROSS MUCH OF THE AREA.
TONIGHT AND TOMORROW...MODELS HAVE BEEN FAIRLY CONSISTENT ON KEEPING
SW FLOW ALOFT ACROSS THE REGION OVER THE NEXT 24 HRS. AN UPPER
DISTURBANCE IN THE LARGE SCALE SW FLOW WILL TRACK ACROSS THE 4
CORNERS REGION AND COLORADO TONIGHT AND TOMORROW...AND WILL BE THE
MAIN DRIVER OF CONVECTION SWEEPING ACROSS THE CWA. THE ENHANCED LTG
ACTIVITY CURRENTLY OCCURRING IN NM IS ASSOCIATED WITH THE BEST
DYNAMICS...AND IT LOOKS AS IF THIS AREA OF BEST FORCING WILL TRACK
ACROSS SOUTHERN NM TONIGHT...THEN UP ACROSS EASTERN NM...THE
PANHANDLES AND EASTERN COLORADO WED AFTN. THEREFORE...FEEL THAT
STEADILY INCREASING CLOUD COVER AND PCPN CHANCES FOR THE HIGHER
ELEVATIONS THIS EVE AND OVERNIGHT LOOKS REASONABLE...BUT THE
BULLSEYE FOR CONVECTION WILL THEN FOCUS ON THE SE QUAD OF THE STATE
BEGINNING AFTER 18Z. THE ENTIRE FORECAST AREA IS OUTLOOKED FOR
GENERAL THUNDER TOMORROW...AND LATEST NAM GUIDANCE INDICATE 600-700
J/KG OF CAPE FOR THE SE CORNER SO DO NOT BELIEVE THE AREA WILL SEE
MUCH BY WAY OF SEVERE WX...BUT THUNDERSTORM ACTIVITY IS PROBABLE. AS
FOR TEMPS...INCREASED CLOUD COVER SHOULD KEEP TEMPS MILD TONIGHT
WITH OVERNIGHT MINS IN THE 40S TO NEAR 50F...AND MAX TEMPS TOMORROW
IN THE 60S. MOORE
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 337 PM MDT TUE MAY 12 2015
.WEDNESDAY NIGHT THROUGH FRIDAY...DISTURBANCE EXITS THE STATE
WEDNESDAY EVENING. KEPT HIGHER POPS OVER THE EASTERN PLAINS CLOSER
TO THE KANSAS BORDER. ANTICIPATE NEARLY ALL THE PRECIPITATION
WILL BE EAST OF COLORADO BY MIDNIGHT. ON THURSDAY...STRONG TROUGH
WILL START LIFTING NORTHEASTWARD FROM SOUTHERN CALIFORNIA INTO
WYOMING. ISOLATED TO SCATTERED CONVECTION WILL DEVELOP DURING THE
AFTERNOON AS A WEAK DISTURBANCE MOVES UP FROM THE SOUTHWEST. WEAK
LEE TROUGH WILL DEVELOP OVER THE PLAINS DURING THE DAY...WITH MUCH
OF THE LOWER LEVEL MOISTURE REMAINING IN KANSAS. WITH LOW CAPE
VALUES...DO NOT ANTICIPATE ANY STRONG STORMS. ON FRIDAY...DRY SLOT
MOVES INTO THE EASTERN HALF OF THE CWA FROM THE SOUTHWEST. MODELS
HAVE TRENDED TO HAVE THE DRY LINE BE FURTHER EAST...MOSTLY OUT OF
COLORADO. IF THIS TREND CONTINUES...THREAT FOR SEVERE CONVECTIVE
WEATHER WILL BE LESS THAN EARLIER ANTICIPATED. THERE WILL BE
ENOUGH MOISTURE AND INSTABILITY FOR STORMS OVER THE MOUNTAINS
DURING THE DAY ON FRIDAY.
.SATURDAY AND SUNDAY...TROUGH WILL CONTINUE MOVING TO THE
NORTHEAST. A DISTURBANCE WILL ROTATE EASTWARD ACROSS THE STATE ON
SATURDAY...WHICH WILL INCREASE PRECIPITATION CHANCES OVER THE
MOUNTAINS. LEE TROUGH WILL BE EAST OF THE COLORADO BORDER ON
SATURDAY...WHICH WILL LIMIT THE AMOUNT OF LOW LEVEL MOISTURE ON
THE PLAINS. ON SUNDAY...TROUGH WILL MOVE WELL EAST OF THE REGION.
DIURNAL CONVECTION WILL MOSTLY BE CONFINED TO THE MOUNTAINS. COLD
FRONT WILL PASS OVER THE PLAINS ON SUNDAY...BUT MOISTURE BEHIND
THE FRONT WILL BE LIMITED.
.MONDAY AND TUESDAY...TROUGH RELOADS OVER CALIFORNIA...WITH A
DISTURBANCE PASSING OVER THE REGION TUESDAY OR WEDNESDAY. WITH
LOW LEVEL UPSLOPE CONTINUING...TUESDAY HAS THE POTENTIAL TO BE A
WET DAY. CURRENTLY...DID NOT GO VERY HIGH WITH THE POPS AS THIS IS
DAY 7. THERE ARE STILL ISSUES WITH THE TIMING AND STRENGTH OF THE
TROUGH. --PGW--
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1106 PM MDT TUE MAY 12 2015
KALS...SHOWERS ARE FORECAST TO MOVE INTO THE SAN LUIS VALLEY
OVERNIGHT BRINGING MVFR CONDITIONS TO THE TERMINAL DUE TO REDUCED
CIGS AND VIS. THERE WILL LIKELY BE A BREAK WEDNESDAY MORNING WITH
THUNDERSTORMS DEVELOPING WEDNESDAY AFTERNOON NEAR THE TERMINALS.
KCOS AND KPUB...VFR CONDITIONS OVERNIGHT. SHOWERS AND
THUNDERSTORMS ARE EXPECTED ON WEDNESDAY AFTERNOON WITH MAY BRING
REDUCED CIGS AND VIS TO THE TERMINALS. MOZLEY
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KT
SHORT TERM...MOORE
LONG TERM...PGW
AVIATION...MOZLEY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
946 PM CDT THU MAY 14 2015
.UPDATE...
941 PM CDT
LIGHTNING STRIKES HAVE BEEN LIMITED SOUTH OF THE AREA THIS
EVENING. WHILE THE FIRST MAIN WAVE OF RAIN IS THROUGH...ADDITIONAL
SHOWERS WILL CONTINUE THIS EVENING AREA WIDE...WITH THE FOCUS
SHIFTING FARTHER SOUTH THROUGH THE NIGHT. WHILE THE THUNDER WAS
REMOVED FOR THE EVENING PERIOD...WILL HOLD ONTO THE ISOLATED
THUNDER MENTION OVERNIGHT AS BETTER LAPSE RATES ALOFT ADVECT
NORTHWARD AND RAP HANGS ONTO SOME WEAK MOST UNSTABLE CAPE. ONE
LONE CLOUD TO GROUND STRIKE OCCURRED IN CHAMPAIGN COUNTY NOT TOO
LONG AGO. AREAS SOUTH OF I-80 HOLD THE BEST CHANCE FOR AN ISOLATED
STRIKE OR TWO.
KMD
&&
.SHORT TERM...
253 PM CDT
THROUGH FRIDAY...
AN ELONGATED NEGATIVELY-TILTED UPPER TROUGH...EXTENDING FROM THE RED
RIVER VALLEY OF THE NORTH TO SOUTHERN ILLINOIS THIS AFTERNOON...WILL
CONTINUE ITS ADVANCE NORTHEAST TONIGHT. WHILE THERE ARE MULTIPLE
EMBEDDED SHORT WAVE IMPULSES WITHIN THIS...THE MOST PRONOUNCED FOR
OUR AREA IS A CIRCULATION CENTER NEAR THE IA/MO/IL BORDER. FOCUSED
ASCENT JUST AHEAD OF THIS IS IN TANDEM WITH A 40 KT LOW-LEVEL JET
PER ILX AND LSX VWP DATA...AND REGIONAL RADAR MOSAIC INDICATES
SHOWERS INCREASING IN COVERAGE AND INTENSITY ACROSS WESTERN ILLINOIS
AND EASTERN MISSOURI AS OF 230 PM.
THIS FAVORED AREA OF FORCING AND SHOWERS WILL EXPAND INTO THE
ILLINOIS FORECAST AREA BY EARLY EVENING. HAVE GONE AS DETERMINISTIC
AS COULD WITH HOURLY POPS...LEVERAGING SOME ON CONVECTIVE ALLOWING
MODELS/ENSEMBLES AND MORE SO OBSERVATIONAL TRENDS. DEEPER PWATS
AROUND 1.4 INCHES AND SLIGHTLY BETTER LAPSE RATES ALOFT IMMEDIATELY
AHEAD OF THE CIRCULATION SUPPORT CHANCES FOR ISOLATED EMBEDDED
THUNDER THIS EVENING. TOO LITTLE OF RECOVERY TIME FOR LAPSE RATES
SHOULD STUNT ANY SEVERE WEATHER THREAT.
THE MAIN CHANGE WITH THE FORECAST FOR TONIGHT WAS TO DIMINISH...AND
IN MANY PLACES END... POPS EARLIER OVERNIGHT FROM SOUTHWEST TO
NORTHEAST...BASED HEAVILY ON UPSTREAM OBSERVATIONAL TRENDS WITH HOUR-
TO-HOUR RUNS OF THE RAP/HRRR SEEM TO BE CATCHING UP ON. EXPECT THE
ILLINOIS FORECAST AREA TO HAVE THE LONGEST TIME WITH SHOWERS
/4-6 HOURS/ AND SOME PLACES TO FINISH AROUND ONE HALF INCH...WHILE
TAPERING TO NEAR OR UNDER ONE QUARTER OF AN INCH INTO NORTHWEST
INDIANA.
SIZABLE PRESSURE FALLS AT THE SURFACE WILL KEEP UP SOUTHEAST WINDS
TONIGHT AND TEMPERATURES REALLY SHOULD ONLY DROP BY WET BULB
COOLING. THE WINDS SHOULD ALSO PREVENT FOG FROM BEING MUCH OF A
PROBLEM ONCE THE RAIN ENDS...AT LEAST OVER LAND. LOWS ARE EXPECTED
IN THE MID-UPPER 50S AREAWIDE.
DURING THE DAY FRIDAY FORCING IS FAIRLY MINIMAL FOR RAIN...SO
CONTINUE POPS LOW OR NON-MENTIONABLE. A SYNOPTIC BOUNDARY STARTS TO
TAKE SHAPE FROM EAST-TO-WEST ACROSS CENTRAL ILLINOIS AND
CONVERGENCE/MOISTURE TRANSPORT INTO AND ALONG THIS WILL START TO
GRADUALLY STRENGTHEN DURING THE AFTERNOON. THIS IS WHERE HAVE KEPT
THE POPS. CONFIDENCE IS SOMEWHAT SHAKE ON HOW QUICKLY CLOUDS
SCATTER...BUT HAVE HIGHS RECOVERING FROM MID 70S TO LOWER 80S FROM
NORTH-TO-SOUTH.
MTF
&&
.LONG TERM...
253 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
UPPER LEVEL RIDGING WILL TRANSLATE ACROSS NORTHERN ILLINOIS FRIDAY
NIGHT INTO EARLY SATURDAY HOWEVER BOTH THE NAM AND GFS ADVERTISE
A SUBTLE SHORTWAVE EMBEDDED WITHIN THE UPPER RIDGE LIFTING ACROSS
THE AREA FRIDAY NIGHT. SOUNDINGS SHOW MODEST INSTABILITY WILL BE
IN PLACE OVERNIGHT AND ANY LIFT ASSOCIATED WITH THE SHORTWAVE MAY
BE ABLE TO TRIGGER A FEW THUNDERSTORMS. FORCING IS OTHERWISE
FAIRLY WEAK SO THINK COVERAGE SHOULD BE FAIRLY SCATTERED.
MEANWHILE...JET STREAM ROUNDING THE BASE OF THE LONGWAVE TROUGH
CENTERED OVER THE INTERMOUNTAIN WEST WILL LIFT INTO THE CENTRAL
PLAINS SATURDAY WITH SURFACE LOW DEVELOPING OVER WESTERN KS/NE
SATURDAY AFTERNOON. THE MIDWEST WILL ALREADY BE UNDER A MOIST
AIRMASS WITH WIDE OPEN GULF...BUT THIS NEXT WAVE WILL FURTHER
INCREASE MOISTURE WITH PWATS PUSHING 1.5-1.6 INCHES BY LATER IN THE
DAY SATURDAY. HIGHS IN THE LOW TO MID 80S AND SURFACE DEW POINTS IN
THE MID 60S WILL RESULT IN MODERATE INSTABILITY ACROSS THE
AREA...WEAKLY CAPPED OR UNCAPPED PER FORECAST SOUNDINGS. MOST
MODELS INDICATE WIDESPREAD CONVECTIVE ACTIVITY IN THE WARM
SECTOR ACROSS THE MIDWEST AND MISSISSIPPI RIVER VALLEY WHILE THE
MOST FOCUSED FORCING REMAINS WEST OF THE MISSISSIPPI RIVER. GIVEN
THE INSTABILITY AND WEAK FORCING...WILL BE HARD TO PIN DOWN MOST
FAVORED AREAS FOR THUNDERSTORM ACTIVITY BUT GENERALLY EXPECT
SCATTERED UNORGANIZED ACTIVITY WHICH MAY END UP BEING DIURNALLY
FAVORED.
A LOW LEVEL JET FORMS SATURDAY NIGHT FOCUSED ACROSS THE MID-
MISSOURI VALLEY AND SHIFTING EAST ACROSS IOWA DURING THE
OVERNIGHT HOURS. BEST PRECIP CHANCES WILL BE ACROSS THESE AREAS
SATURDAY NIGHT WHILE MODELS CONTINUE TO PRODUCE WIDELY SCATTERED
UNORGANIZED ACTIVITY ACROSS THE LOCAL FORECAST AREA GIVEN THE
CONTINUED INSTABILITY.
SUNDAY CONTINUES TO APPEAR AT LEAST FAVORABLE FOR SEVERE WEATHER
IN THE AREA. EARLY DAY SOUNDINGS SHOW A CAP IN PLACE WHICH
SHOULD HELP ANY FESTERING NOCTURNAL CONVECTION MOVING IN FROM OUR
WEST DISSIPATE...AND FOR INSTABILITY TO BUILD THROUGH THE MORNING
AND EARLY AFTERNOON. MID/HIGH LEVEL CLOUD COVER MAY IMPEDE
INSOLATION SOME...HOWEVER GUIDANCE CONTINUES TO ADVERTISE A
CORRIDOR OF 1000+ J/KG MLCAPE AHEAD OF THE COLD FRONT MOVING
ACROSS NORTHERN ILLINOIS LATE AFTERNOON INTO THE EVENING. IN
ADDITION...NEGATIVELY TILTED TROUGH IS PROGGED TO LIFT INTO THE
UPPER MIDWEST SUNDAY WHICH SHOULD HELP ERODE THE CAP...AND THE JET
STREAM ADVECTS OVERHEAD RESULTING IN INCREASING DEEP LAYER SHEAR.
LATEST GFS ADVERTISES 35-45 KT OF FAIRLY UNIDIRECTIONAL 0-6KM
SHEAR MOVING OVER THE AREA WHICH WILL BE SUFFICIENT TO SUPPORT AN
ORGANIZED SEVERE WEATHER THREAT SHOULD THE INSTABILITY AND FORCING
MATERIALIZE AS EXPECTED.
THE COLD FRONT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWEST
INDIANA EARLY ON MONDAY WITH INITIALLY BREEZY NORTHWEST/NORTH WIND
BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. COLD ADVECTION AND WINDS TURNING OFF OF LAKE MICHIGAN
WILL RESULT IN TEMPERATURES RETURNING TO COLDER THAN NORMAL
LEVELS...ESPECIALLY TUESDAY WHERE HIGHS MAY ONLY TOP OUT IN THE
50S...THEN GRADUALLY MODERATING AS WE HEAD THROUGH MIDWEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* RA/SHRA THROUGH LATE TONIGHT...BECMG MORE SCT AFTER MIDNIGHT.
* CIGS LOWERING TO IFR DURG LATE NIGHT/EARLY MORNING HOURS...
IMPROVING TO VFR BY LATE MORNING.
* OCNL MVFR VIS IN MORE STEADY RAIN THIS EVENING.
KREIN
//DISCUSSION...UPDATED 00Z...
AN UPPER LOW LIFTING NEWD THROUGH THE MIDDLE MISSISSIPPI VALLEY IS
SPREADING RAIN ACROSS THE REGION. CHANCES FOR THUNDER SHOULD BE
MINIMAL...AND IF ANY WERE TO OCCUR IT WOULD BE RIGHT UNDER THE
UPPER LOW CENTER AND LIKELY WOULD NOT IMPACT THE TERMINALS.
OF GREATER CONCERN WILL BE POTENTIAL FOR IFR CIGS AND LLWS. LATEST
GUIDANCE AND UPSTREAM OBS INDICATING THAT THE LOWER LEVELS SHOULD
CONTINUE TO SATURATE THROUGH THE EVENING AND OVERNIGHT...WITH
FALLING RAIN AIDING THE LOWERING OF CLOUD BASES TO IFR LEVELS BY
ARND 09Z AND THEN GRADUALLY IMPROVE THROUGH THE MORNING...BECMG
PREVAILING VFR BY LATE MORNING. AS SFC DROP OFF AFTER
SUNSET...STRONGER WINDS ALOFT WILL OVERSPREAD THE REGION WITH SWLY
WINDS OF 35-40KT AT 1500-2000FT AGL...ABOVE A SFC BASED INVERSION.
LATEST WIND PROFILE GUIDANCE SUGGESTS THAT THE WINDS ALOFT WILL
DROP OFF TO ARND 20-25KT ABOVE THE INVERSION LEVEL...ENDING THE
POTENTIAL FOR LLWS BY ARND 09Z.
WINDS WILL REMAIN SWLY AT 10-15KT THROUGH MUCH OF THE THE DAY
TOMORROW...BUT THE PRESSURE GRADIENT OVER THE REGION WILL WEAKEN
IN THE AFTERNOON...INTRODUCING THE POTENTIAL FOR WINDS TO
WEAKEN...ALLOWING A LAKE BREEZE TO DEVELOP. HOWEVER...THE LAKE
BREEZE IS A LOW CONFIDENCE SCENARIO SINCE THERE IS STILL A CHANCE
THAT LOW LEVEL MIXING COULD KEEP SWLY SFC WINDS STRONG ENOUGH TO
LOWER THE POTENTIAL FOR A LAKE BREEZE TO FORM OR MOVE INLAND FAR
ENOUGH TO IMPACT THE TERMINALS.
AN UPPER LEVEL IMPULSE IS EXPECTED TO CROSS THE AREA TOMORROW
EVENING WHICH COULD BRING A CHANCE FOR SOME THUNDERSTORMS. TIMING
AT THIS POINT IS STILL A BIT UNCERTAIN...SO HAVE ONLY INTRODUCED A
PROB30 TO THE EXTENDED PORTION OF THE ORD TAF.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM TO HIGH CONFIDENCE IN LLWS AND GENERAL WIND TRENDS.
* HIGH CONFIDENCE IN CIGS LOWERING TO IFR...BUT ONLY MEDIUM
CONFIDENCE IN TIMING OF LOWERING TO IFR AND IMPROVING TO MVFR
AND EVENTUALLY VFR.
* LOW CONFIDENCE IN LAKE BREEZE DEVELOPMENT AND IMPACT ON THE
TERMINALS.
* LOW CONFIDENCE IN TIMING AND COVERAGE OF TSRA TOMORROW EVENING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE. MODERATE SOUTH WINDS.
SUNDAY...SHRA/TSRA LIKELY. MVFR POSSIBLE. STRONG/GUSTY SOUTH
WINDS.
MONDAY...SLIGHT CHANCE LINGERING SHRA EARLY. WINDS TURNING
NWLY...THEN NLY OVERNIGHT.
TUESDAY AND WEDNESDAY...VFR/WX NIL. MODERATE NELY TO ELY WINDS.
KREIN
&&
.MARINE...
253 PM CDT
HIGH PRESSURE IS CENTERED EAST OF LAKE MICHIGAN TODAY AND WILL
MOVE TO THE MID ATLANTIC COAST OVERNIGHT. AS THE HIGH DRIFTS
EAST...SOUTHEAST WINDS WILL FRESHEN UP ACROSS LAKE MICHIGAN
TONIGHT. A WEAK LOW WILL TRAVERSE THE REGION FRIDAY LIFTING A WARM
FRONT NORTH ACROSS THE LAKE...THEN A SECOND STRONGER LOW WILL TAKE
SHAPE OVER THE PLAINS FRIDAY AND LIFT INTO THE UPPER MIDWEST BY
SUNDAY BRINGING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
IN ADDITION...MOISTURE WILL INCREASE ACROSS THE REGION AND STABLE
CONDITIONS OVER THE LAKE WILL BE FAVORABLE FOR FOG TO DEVELOP FOR
MUCH OF THE WEEKEND. A COLD FRONT WILL SWEEP ACROSS LAKE MICHIGAN
EARLY MONDAY AND TURNING WINDS WESTERLY AND SHOULD MARK AND END
FOR PRECIP AND FOG CHANCES.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
943 PM CDT THU MAY 14 2015
.UPDATE...
941 PM CDT
LIGHTNING STRIKES HAVE BEEN LIMITED SOUTH OF THE AREA THIS
EVENING. WHILE THE FIRST MAIN WAVE OF RAIN IS THROUGH...ADDITIONAL
SHOWERS WILL CONTINUE THIS EVENING AREA WIDE...WITH THE FOCUS
SHIFTING FARTHER SOUTH THROUGH THE NIGHT. WHILE THE THUNDER WAS
REMOVED FOR THE EVENING PERIOD...WILL HOLD ONTO THE ISOLATED
THUNDER MENTION OVERNIGHT AS BETTER LAPSE RATES ALOFT ADVECT
NORTHWARD AND RAP HANGS ONTO SOME WEAK MOST UNSTABLE CAPE. ONE
LONE CLOUD TO GROUND STRIKE OCCURRED IN CHAMPAIGN COUNTY NOT TOO
LONG AGO. AREAS SOUTH OF I-80 HOLD THE BEST CHANCE FOR AN ISOLATED
STRIKE OR TWO.
KMD
&&
.SHORT TERM...
253 PM CDT
THROUGH FRIDAY...
AN ELONGATED NEGATIVELY-TILTED UPPER TROUGH...EXTENDING FROM THE RED
RIVER VALLEY OF THE NORTH TO SOUTHERN ILLINOIS THIS AFTERNOON...WILL
CONTINUE ITS ADVANCE NORTHEAST TONIGHT. WHILE THERE ARE MULTIPLE
EMBEDDED SHORT WAVE IMPULSES WITHIN THIS...THE MOST PRONOUNCED FOR
OUR AREA IS A CIRCULATION CENTER NEAR THE IA/MO/IL BORDER. FOCUSED
ASCENT JUST AHEAD OF THIS IS IN TANDEM WITH A 40 KT LOW-LEVEL JET
PER ILX AND LSX VWP DATA...AND REGIONAL RADAR MOSAIC INDICATES
SHOWERS INCREASING IN COVERAGE AND INTENSITY ACROSS WESTERN ILLINOIS
AND EASTERN MISSOURI AS OF 230 PM.
THIS FAVORED AREA OF FORCING AND SHOWERS WILL EXPAND INTO THE
ILLINOIS FORECAST AREA BY EARLY EVENING. HAVE GONE AS DETERMINISTIC
AS COULD WITH HOURLY POPS...LEVERAGING SOME ON CONVECTIVE ALLOWING
MODELS/ENSEMBLES AND MORE SO OBSERVATIONAL TRENDS. DEEPER PWATS
AROUND 1.4 INCHES AND SLIGHTLY BETTER LAPSE RATES ALOFT IMMEDIATELY
AHEAD OF THE CIRCULATION SUPPORT CHANCES FOR ISOLATED EMBEDDED
THUNDER THIS EVENING. TOO LITTLE OF RECOVERY TIME FOR LAPSE RATES
SHOULD STUNT ANY SEVERE WEATHER THREAT.
THE MAIN CHANGE WITH THE FORECAST FOR TONIGHT WAS TO DIMINISH...AND
IN MANY PLACES END... POPS EARLIER OVERNIGHT FROM SOUTHWEST TO
NORTHEAST...BASED HEAVILY ON UPSTREAM OBSERVATIONAL TRENDS WITH HOUR-
TO-HOUR RUNS OF THE RAP/HRRR SEEM TO BE CATCHING UP ON. EXPECT THE
ILLINOIS FORECAST AREA TO HAVE THE LONGEST TIME WITH SHOWERS
/4-6 HOURS/ AND SOME PLACES TO FINISH AROUND ONE HALF INCH...WHILE
TAPERING TO NEAR OR UNDER ONE QUARTER OF AN INCH INTO NORTHWEST
INDIANA.
SIZABLE PRESSURE FALLS AT THE SURFACE WILL KEEP UP SOUTHEAST WINDS
TONIGHT AND TEMPERATURES REALLY SHOULD ONLY DROP BY WET BULB
COOLING. THE WINDS SHOULD ALSO PREVENT FOG FROM BEING MUCH OF A
PROBLEM ONCE THE RAIN ENDS...AT LEAST OVER LAND. LOWS ARE EXPECTED
IN THE MID-UPPER 50S AREAWIDE.
DURING THE DAY FRIDAY FORCING IS FAIRLY MINIMAL FOR RAIN...SO
CONTINUE POPS LOW OR NON-MENTIONABLE. A SYNOPTIC BOUNDARY STARTS TO
TAKE SHAPE FROM EAST-TO-WEST ACROSS CENTRAL ILLINOIS AND
CONVERGENCE/MOISTURE TRANSPORT INTO AND ALONG THIS WILL START TO
GRADUALLY STRENGTHEN DURING THE AFTERNOON. THIS IS WHERE HAVE KEPT
THE POPS. CONFIDENCE IS SOMEWHAT SHAKE ON HOW QUICKLY CLOUDS
SCATTER...BUT HAVE HIGHS RECOVERING FROM MID 70S TO LOWER 80S FROM
NORTH-TO-SOUTH.
MTF
&&
.LONG TERM...
253 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
UPPER LEVEL RIDGING WILL TRANSLATE ACROSS NORTHERN ILLINOIS FRIDAY
NIGHT INTO EARLY SATURDAY HOWEVER BOTH THE NAM AND GFS ADVERTISE
A SUBTLE SHORTWAVE EMBEDDED WITHIN THE UPPER RIDGE LIFTING ACROSS
THE AREA FRIDAY NIGHT. SOUNDINGS SHOW MODEST INSTABILITY WILL BE
IN PLACE OVERNIGHT AND ANY LIFT ASSOCIATED WITH THE SHORTWAVE MAY
BE ABLE TO TRIGGER A FEW THUNDERSTORMS. FORCING IS OTHERWISE
FAIRLY WEAK SO THINK COVERAGE SHOULD BE FAIRLY SCATTERED.
MEANWHILE...JET STREAM ROUNDING THE BASE OF THE LONGWAVE TROUGH
CENTERED OVER THE INTERMOUNTAIN WEST WILL LIFT INTO THE CENTRAL
PLAINS SATURDAY WITH SURFACE LOW DEVELOPING OVER WESTERN KS/NE
SATURDAY AFTERNOON. THE MIDWEST WILL ALREADY BE UNDER A MOIST
AIRMASS WITH WIDE OPEN GULF...BUT THIS NEXT WAVE WILL FURTHER
INCREASE MOISTURE WITH PWATS PUSHING 1.5-1.6 INCHES BY LATER IN THE
DAY SATURDAY. HIGHS IN THE LOW TO MID 80S AND SURFACE DEW POINTS IN
THE MID 60S WILL RESULT IN MODERATE INSTABILITY ACROSS THE
AREA...WEAKLY CAPPED OR UNCAPPED PER FORECAST SOUNDINGS. MOST
MODELS INDICATE WIDESPREAD CONVECTIVE ACTIVITY IN THE WARM
SECTOR ACROSS THE MIDWEST AND MISSISSIPPI RIVER VALLEY WHILE THE
MOST FOCUSED FORCING REMAINS WEST OF THE MISSISSIPPI RIVER. GIVEN
THE INSTABILITY AND WEAK FORCING...WILL BE HARD TO PIN DOWN MOST
FAVORED AREAS FOR THUNDERSTORM ACTIVITY BUT GENERALLY EXPECT
SCATTERED UNORGANIZED ACTIVITY WHICH MAY END UP BEING DIURNALLY
FAVORED.
A LOW LEVEL JET FORMS SATURDAY NIGHT FOCUSED ACROSS THE MID-
MISSOURI VALLEY AND SHIFTING EAST ACROSS IOWA DURING THE
OVERNIGHT HOURS. BEST PRECIP CHANCES WILL BE ACROSS THESE AREAS
SATURDAY NIGHT WHILE MODELS CONTINUE TO PRODUCE WIDELY SCATTERED
UNORGANIZED ACTIVITY ACROSS THE LOCAL FORECAST AREA GIVEN THE
CONTINUED INSTABILITY.
SUNDAY CONTINUES TO APPEAR AT LEAST FAVORABLE FOR SEVERE WEATHER
IN THE AREA. EARLY DAY SOUNDINGS SHOW A CAP IN PLACE WHICH
SHOULD HELP ANY FESTERING NOCTURNAL CONVECTION MOVING IN FROM OUR
WEST DISSIPATE...AND FOR INSTABILITY TO BUILD THROUGH THE MORNING
AND EARLY AFTERNOON. MID/HIGH LEVEL CLOUD COVER MAY IMPEDE
INSOLATION SOME...HOWEVER GUIDANCE CONTINUES TO ADVERTISE A
CORRIDOR OF 1000+ J/KG MLCAPE AHEAD OF THE COLD FRONT MOVING
ACROSS NORTHERN ILLINOIS LATE AFTERNOON INTO THE EVENING. IN
ADDITION...NEGATIVELY TILTED TROUGH IS PROGGED TO LIFT INTO THE
UPPER MIDWEST SUNDAY WHICH SHOULD HELP ERODE THE CAP...AND THE JET
STREAM ADVECTS OVERHEAD RESULTING IN INCREASING DEEP LAYER SHEAR.
LATEST GFS ADVERTISES 35-45 KT OF FAIRLY UNIDIRECTIONAL 0-6KM
SHEAR MOVING OVER THE AREA WHICH WILL BE SUFFICIENT TO SUPPORT AN
ORGANIZED SEVERE WEATHER THREAT SHOULD THE INSTABILITY AND FORCING
MATERIALIZE AS EXPECTED.
THE COLD FRONT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWEST
INDIANA EARLY ON MONDAY WITH INITIALLY BREEZY NORTHWEST/NORTH WIND
BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. COLD ADVECTION AND WINDS TURNING OFF OF LAKE MICHIGAN
WILL RESULT IN TEMPERATURES RETURNING TO COLDER THAN NORMAL
LEVELS...ESPECIALLY TUESDAY WHERE HIGHS MAY ONLY TOP OUT IN THE
50S...THEN GRADUALLY MODERATING AS WE HEAD THROUGH MIDWEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* SELY WINDS GUSTING TO ARND 20KT THROUGH EARLY EVENING.
* RA/SHRA THROUGH LATE TONIGHT...BECMG MORE SCT AFTER MIDNIGHT.
* CIGS LOWERING TO IFR DURG LATE NIGHT/EARLY MORNING
HOURS...IMPROVING TO VFR BY LATE MORNING.
* OCNL MVFR VIS IN MORE STEADY RAIN THIS EVENING.
KREIN
//DISCUSSION...UPDATED 00Z...
AN UPPER LOW LIFTING NEWD THROUGH THE MIDDLE MISSISSIPPI VALLEY IS
SPREADING RAIN ACROSS THE REGION. CHANCES FOR THUNDER SHOULD BE
MINIMAL...AND IF ANY WERE TO OCCUR IT WOULD BE RIGHT UNDER THE
UPPER LOW CENTER AND LIKELY WOULD NOT IMPACT THE TERMINALS.
OF GREATER CONCERN WILL BE POTENTIAL FOR IFR CIGS AND LLWS. LATEST
GUIDANCE AND UPSTREAM OBS INDICATING THAT THE LOWER LEVELS SHOULD
CONTINUE TO SATURATE THROUGH THE EVENING AND OVERNIGHT...WITH
FALLING RAIN AIDING THE LOWERING OF CLOUD BASES TO IFR LEVELS BY
ARND 09Z AND THEN GRADUALLY IMPROVE THROUGH THE MORNING...BECMG
PREVAILING VFR BY LATE MORNING. AS SFC DROP OFF AFTER
SUNSET...STRONGER WINDS ALOFT WILL OVERSPREAD THE REGION WITH SWLY
WINDS OF 35-40KT AT 1500-2000FT AGL...ABOVE A SFC BASED INVERSION.
LATEST WIND PROFILE GUIDANCE SUGGESTS THAT THE WINDS ALOFT WILL
DROP OFF TO ARND 20-25KT ABOVE THE INVERSION LEVEL...ENDING THE
POTENTIAL FOR LLWS BY ARND 09Z.
WINDS WILL REMAIN SWLY AT 10-15KT THROUGH MUCH OF THE THE DAY
TOMORROW...BUT THE PRESSURE GRADIENT OVER THE REGION WILL WEAKEN
IN THE AFTERNOON...INTRODUCING THE POTENTIAL FOR WINDS TO
WEAKEN...ALLOWING A LAKE BREEZE TO DEVELOP. HOWEVER...THE LAKE
BREEZE IS A LOW CONFIDENCE SCENARIO SINCE THERE IS STILL A CHANCE
THAT LOW LEVEL MIXING COULD KEEP SWLY SFC WINDS STRONG ENOUGH TO
LOWER THE POTENTIAL FOR A LAKE BREEZE TO FORM OR MOVE INLAND FAR
ENOUGH TO IMPACT THE TERMINALS.
AN UPPER LEVEL IMPULSE IS EXPECTED TO CROSS THE AREA TOMORROW
EVENING WHICH COULD BRING A CHANCE FOR SOME THUNDERSTORMS. TIMING
AT THIS POINT IS STILL A BIT UNCERTAIN...SO HAVE ONLY INTRODUCED A
PROB30 TO THE EXTENDED PORTION OF THE ORD TAF.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM TO HIGH CONFIDENCE IN LLWS AND GENERAL WIND TRENDS.
* HIGH CONFIDENCE IN CIGS LOWERING TO IFR...BUT ONLY MEDIUM
CONFIDENCE IN TIMING OF LOWERING TO IFR AND IMPROVING TO MVFR
AND EVENTUALLY VFR.
* LOW CONFIDENCE IN LAKE BREEZE DEVELOPMENT AND IMPACT ON THE
TERMINALS.
* LOW CONFIDENCE IN TIMING AND COVERAGE OF TSRA TOMORROW EVENING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE. MODERATE SOUTH WINDS.
SUNDAY...SHRA/TSRA LIKELY. MVFR POSSIBLE. STRONG/GUSTY SOUTH
WINDS.
MONDAY...SLIGHT CHANCE LINGERING SHRA EARLY. WINDS TURNING
NWLY...THEN NLY OVERNIGHT.
TUESDAY AND WEDNESDAY...VFR/WX NIL. MODERATE NELY TO ELY WINDS.
KREIN
&&
.MARINE...
253 PM CDT
HIGH PRESSURE IS CENTERED EAST OF LAKE MICHIGAN TODAY AND WILL
MOVE TO THE MID ATLANTIC COAST OVERNIGHT. AS THE HIGH DRIFTS
EAST...SOUTHEAST WINDS WILL FRESHEN UP ACROSS LAKE MICHIGAN
TONIGHT. A WEAK LOW WILL TRAVERSE THE REGION FRIDAY LIFTING A WARM
FRONT NORTH ACROSS THE LAKE...THEN A SECOND STRONGER LOW WILL TAKE
SHAPE OVER THE PLAINS FRIDAY AND LIFT INTO THE UPPER MIDWEST BY
SUNDAY BRINGING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
IN ADDITION...MOISTURE WILL INCREASE ACROSS THE REGION AND STABLE
CONDITIONS OVER THE LAKE WILL BE FAVORABLE FOR FOG TO DEVELOP FOR
MUCH OF THE WEEKEND. A COLD FRONT WILL SWEEP ACROSS LAKE MICHIGAN
EARLY MONDAY AND TURNING WINDS WESTERLY AND SHOULD MARK AND END
FOR PRECIP AND FOG CHANCES.
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:
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
906 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 906 PM CDT THU MAY 14 2015
SCATTERED SHOWERS CONTINUE TO MOVE ACROSS THE AREA, MAINLY NORTH
OF I-70. ALREADY MADE ONE ADJUSTMENT TO WX GRIDS TO REMOVE MENTION
OF THUNDER...BUT WILL BE MAKING ANOTHER ADJUSTMENT TO POPS FOR
REMAINDER OF THE NIGHT. HRRR MODEL CONTINUES TO DEVELOP SCATTERED
PCPN JUST TO THE WEST OF THE AREA AND MOVE IT INTO THE CWA.
THEREFORE WILL KEEP SCATTERED SHOWERS MENTIONED IN FORECAST GRIDS.
REMAINDER OF FORECAST LOOK OK BUT WILL SENDING AN UPDATE SHORTLY.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 206 PM CDT THU MAY 14 2015
SHOWERS THUS FAR HAVE CONTINUED TO BATTLE A VERY DRY AIRMASS OVER
CENTRAL ILLINOIS. HOWEVER...A MORE ROBUST AREA OF SHOWERS ASSOCIATED
WITH THE UPPER LOW CURRENTLY TRACKING ACROSS NORTHERN MISSOURI WILL
BE ARRIVING IN THE ILLINOIS RIVER VALLEY BY MID AFTERNOON. THE HRRR
MODEL...WHICH HAS BEEN DOING A DECENT JOB THUS FAR...SHOWS SOME
ADDITIONAL DEVELOPMENT WEST OF I-55 LATE AFTERNOON INTO THE
EVENING... AND HAVE CONCENTRATED THE HIGHER POP`S IN THESE AREAS.
HIGHER-RESOLUTION MODELS SUCH AS THE HRRR AND NMM/ARW AGREE WITH THE
NAM SOLUTION OF THE EVOLUTION OF A MORE EAST-WEST CONFIGURATION OF
SHOWERS ROUGHLY CENTERED ALONG I-72 BY MIDNIGHT. THUNDER UPSTREAM IN
MISSOURI HAS BEEN MINIMAL THUS FAR...AND INSTABILITY PARAMETERS OFF
THE NAM...RAP AND ARW SUGGEST ANY THUNDER IN OUR AREA WOULD BE MOST
LIKELY ALONG AND WEST OF I-55 TONIGHT.
NOT MUCH OF A DROPOFF EXPECTED IN TEMPERATURES TONIGHT...GENERALLY
REMAINING STEADY IN THE LOWER 60S.
.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 206 PM CDT THU MAY 14 2015
IN THE WAKE OF THE WAVE MOVING ACROSS THE MIDWEST TODAY...HEIGHTS
BUILD BRIEFLY AHEAD OF NEXT WEAKER WAVE MOVING NORTHEAST AROUND WEST
COAST CLOSED LOW. HOWEVER, MODELS ARE CONSISTENT IN REDEVELOPING THE
WARM FRONT OVER CENTRAL ILLINOIS FRIDAY AND WITH THE WEAKER WAVE
APPROACHING FRIDAY AFTERNOON, THUNDERSTORMS WILL LIKELY DEVELOP.
WILL NEED TO RETAIN AT LEAST LOW POPS DESPITE THE RIDGING.
INSTABILITY OF 1500-2000 J/KG WILL BE POSSIBLE ALONG AND TO THE
SOUTH OF THE FRONT IN AREAS THAT SEE A LITTLE SUN THOUGH SHEAR WILL
BE QUITE LIMITED.
AS SOUTHERLY FLOW BECOMES ESTABLISHED...DEW POINTS WILL RESPOND BY
CLIMBING INTO THE 60S FOR FRIDAY AFTERNOON AND THE WEEKEND. AS THE
WEST COAST ENERGY BEGINS TO PULL NORTHEAST TOWARD THE GREAT LAKES,
WAVES WILL EJECT FROM THE SYSTEM AND PERIODICALLY CONTRIBUTE TO LIFT
ALONG ANY CONVECTIVELY ENHANCED BOUNDARIES LYING ACROSS THE AREA.
THIS WILL MAKE TIMING OF PRECIPITATION DIFFICULT UNTIL THE MAIN
ENERGY PASSES NORTHWEST OF ILLINOIS ON SUNDAY. WILL HAVE TO
GENERALLY BROADBRUSH GIVEN THE POTENTIAL INSTABILITY (1500-2500
J/KG) IN PLACE. 0-6KM SHEAR IS FORECAST TO REMAIN BELOW 20 KTS
THROUGH SATURDAY EVENING, SO WIDESPREAD SEVERE WEATHER IS NOT
EXPECTED THOUGH GIVEN THE HIGH PRECIPITABLE WATER WOULD NOT BE
SURPRISED TO SEE SOME WET MICROBURST ACTIVITY PRODUCING GUSTY WINDS
AT TIMES SATURDAY.
THE MISSING INGREDIENT (DEEP SHEAR) JOINS THE ENVIRONMENT ON SUNDAY
AS THE MAIN WAVE PASSES NORTHWEST OF ILLINOIS. 0-6KM SHEAR IS
EXPECTED TO SURPASS 40 KTS BY SUNDAY EVENING. THERE DOES SEEM TO
BE POTENTIAL FOR ROTATING UPDRAFTS GIVEN GFS FORECASTED 0-1KM
HELECITY VALUES OF 125-150 M2/S2 AND LCL HEIGHTS BELOW 900 MB.
STORM MOTION ALSO SUGGESTS THAT WINDS MAY BE A THREAT WITH
FORECASTED STORM MOTION AROUND 40 KTS. THREAT WILL LIKELY INCREASE
FROM SOUTHEAST TO NORTHWEST ACROSS FORECAST AREA DUE TO PROXIMITY
OF THE WAVE.
ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH SUNDAY NIGHT AND
MUCH COOLER TEMPERATURES ARE EXPECTED FOR THE BEGINNING OF THE WORK
WEEK. STILL SOME SPREAD IN LATEST MODELS WITH REGARDS TO HOW MUCH
COLD AIR WILL PENETRATE THE MIDWEST BEHIND FRONT WITH THE ECMWF
COOLER THAN GFS/DGEX. HOWEVER, 12Z GFS IS TRENDING TOWARD THIS
COOLER SOLUTION. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS FOR
NOW AND KEEP AT LEAST SOME LOW POPS IN FOR WED THROUGH THU.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 648 PM CDT THU MAY 14 2015
SHOWERS WILL CONTINUE TO MOVE ACROSS THE AREA THIS EVENING BUT
CONDITIONS WILL REMAIN VFR. HOWEVER, SOME BRIEF PERIODS OF MVFR
CONDITIONS WILL OCCUR WITH A HEAVIER SHOWER OR TWO. SO WILL HAVE
TEMPO GROUPS AT ALL SITES THIS EVENING AND AGAIN OVERNIGHT TOWARD
EARLY MORNING. THE BULK OF THE PCPN SHOULD END IN THE MORNING EVEN
WITH A STATIONARY BOUNDARY SITTING ACROSS THE AREA. ADDITIONAL
PCPN IS POSSIBLE TOMORROW, BUT LOCATION AND TIMING IS VERY
UNCERTAIN FOR NOW SO WILL LEAVE OUT. MVFR CIGS WILL PREVAIL
DURING THE MORNING HOURS BUT THEN THING SKIES WILL SCATTER OUT FOR
THE AFTERNOON AT ALL SITES. WINDS WILL BE SOUTHEAST THIS EVENING
BUT THEN BECOME SOUTHWEST FOR TOMORROW. ANY BOUNDARY SITTING
ACROSS THE AREA WILL NOT HAVE ANY EFFECT ON THE WIND DIRECTION
TOMORROW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AUTEN
SHORT TERM...GEELHART
LONG TERM...BARKER
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS LINCOLN IL
648 PM CDT THU MAY 14 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 206 PM CDT THU MAY 14 2015
SHOWERS THUS FAR HAVE CONTINUED TO BATTLE A VERY DRY AIRMASS OVER
CENTRAL ILLINOIS. HOWEVER...A MORE ROBUST AREA OF SHOWERS ASSOCIATED
WITH THE UPPER LOW CURRENTLY TRACKING ACROSS NORTHERN MISSOURI WILL
BE ARRIVING IN THE ILLINOIS RIVER VALLEY BY MID AFTERNOON. THE HRRR
MODEL...WHICH HAS BEEN DOING A DECENT JOB THUS FAR...SHOWS SOME
ADDITIONAL DEVELOPMENT WEST OF I-55 LATE AFTERNOON INTO THE
EVENING... AND HAVE CONCENTRATED THE HIGHER POP`S IN THESE AREAS.
HIGHER-RESOLUTION MODELS SUCH AS THE HRRR AND NMM/ARW AGREE WITH THE
NAM SOLUTION OF THE EVOLUTION OF A MORE EAST-WEST CONFIGURATION OF
SHOWERS ROUGHLY CENTERED ALONG I-72 BY MIDNIGHT. THUNDER UPSTREAM IN
MISSOURI HAS BEEN MINIMAL THUS FAR...AND INSTABILITY PARAMETERS OFF
THE NAM...RAP AND ARW SUGGEST ANY THUNDER IN OUR AREA WOULD BE MOST
LIKELY ALONG AND WEST OF I-55 TONIGHT.
NOT MUCH OF A DROPOFF EXPECTED IN TEMPERATURES TONIGHT...GENERALLY
REMAINING STEADY IN THE LOWER 60S.
.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 206 PM CDT THU MAY 14 2015
IN THE WAKE OF THE WAVE MOVING ACROSS THE MIDWEST TODAY...HEIGHTS
BUILD BRIEFLY AHEAD OF NEXT WEAKER WAVE MOVING NORTHEAST AROUND WEST
COAST CLOSED LOW. HOWEVER, MODELS ARE CONSISTENT IN REDEVELOPING THE
WARM FRONT OVER CENTRAL ILLINOIS FRIDAY AND WITH THE WEAKER WAVE
APPROACHING FRIDAY AFTERNOON, THUNDERSTORMS WILL LIKELY DEVELOP.
WILL NEED TO RETAIN AT LEAST LOW POPS DESPITE THE RIDGING.
INSTABILITY OF 1500-2000 J/KG WILL BE POSSIBLE ALONG AND TO THE
SOUTH OF THE FRONT IN AREAS THAT SEE A LITTLE SUN THOUGH SHEAR WILL
BE QUITE LIMITED.
AS SOUTHERLY FLOW BECOMES ESTABLISHED...DEW POINTS WILL RESPOND BY
CLIMBING INTO THE 60S FOR FRIDAY AFTERNOON AND THE WEEKEND. AS THE
WEST COAST ENERGY BEGINS TO PULL NORTHEAST TOWARD THE GREAT LAKES,
WAVES WILL EJECT FROM THE SYSTEM AND PERIODICALLY CONTRIBUTE TO LIFT
ALONG ANY CONVECTIVELY ENHANCED BOUNDARIES LYING ACROSS THE AREA.
THIS WILL MAKE TIMING OF PRECIPITATION DIFFICULT UNTIL THE MAIN
ENERGY PASSES NORTHWEST OF ILLINOIS ON SUNDAY. WILL HAVE TO
GENERALLY BROADBRUSH GIVEN THE POTENTIAL INSTABILITY (1500-2500
J/KG) IN PLACE. 0-6KM SHEAR IS FORECAST TO REMAIN BELOW 20 KTS
THROUGH SATURDAY EVENING, SO WIDESPREAD SEVERE WEATHER IS NOT
EXPECTED THOUGH GIVEN THE HIGH PRECIPITABLE WATER WOULD NOT BE
SURPRISED TO SEE SOME WET MICROBURST ACTIVITY PRODUCING GUSTY WINDS
AT TIMES SATURDAY.
THE MISSING INGREDIENT (DEEP SHEAR) JOINS THE ENVIRONMENT ON SUNDAY
AS THE MAIN WAVE PASSES NORTHWEST OF ILLINOIS. 0-6KM SHEAR IS
EXPECTED TO SURPASS 40 KTS BY SUNDAY EVENING. THERE DOES SEEM TO
BE POTENTIAL FOR ROTATING UPDRAFTS GIVEN GFS FORECASTED 0-1KM
HELECITY VALUES OF 125-150 M2/S2 AND LCL HEIGHTS BELOW 900 MB.
STORM MOTION ALSO SUGGESTS THAT WINDS MAY BE A THREAT WITH
FORECASTED STORM MOTION AROUND 40 KTS. THREAT WILL LIKELY INCREASE
FROM SOUTHEAST TO NORTHWEST ACROSS FORECAST AREA DUE TO PROXIMITY
OF THE WAVE.
ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH SUNDAY NIGHT AND
MUCH COOLER TEMPERATURES ARE EXPECTED FOR THE BEGINNING OF THE WORK
WEEK. STILL SOME SPREAD IN LATEST MODELS WITH REGARDS TO HOW MUCH
COLD AIR WILL PENETRATE THE MIDWEST BEHIND FRONT WITH THE ECMWF
COOLER THAN GFS/DGEX. HOWEVER, 12Z GFS IS TRENDING TOWARD THIS
COOLER SOLUTION. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS FOR
NOW AND KEEP AT LEAST SOME LOW POPS IN FOR WED THROUGH THU.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 648 PM CDT THU MAY 14 2015
SHOWERS WILL CONTINUE TO MOVE ACROSS THE AREA THIS EVENING BUT
CONDITIONS WILL REMAIN VFR. HOWEVER, SOME BRIEF PERIODS OF MVFR
CONDITIONS WILL OCCUR WITH A HEAVIER SHOWER OR TWO. SO WILL HAVE
TEMPO GROUPS AT ALL SITES THIS EVENING AND AGAIN OVERNIGHT TOWARD
EARLY MORNING. THE BULK OF THE PCPN SHOULD END IN THE MORNING EVEN
WITH A STATIONARY BOUNDARY SITTING ACROSS THE AREA. ADDITIONAL
PCPN IS POSSIBLE TOMORROW, BUT LOCATION AND TIMING IS VERY
UNCERTAIN FOR NOW SO WILL LEAVE OUT. MVFR CIGS WILL PREVAIL
DURING THE MORNING HOURS BUT THEN THING SKIES WILL SCATTER OUT FOR
THE AFTERNOON AT ALL SITES. WINDS WILL BE SOUTHEAST THIS EVENING
BUT THEN BECOME SOUTHWEST FOR TOMORROW. ANY BOUNDARY SITTING
ACROSS THE AREA WILL NOT HAVE ANY EFFECT ON THE WIND DIRECTION
TOMORROW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...BARKER
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1014 PM EDT THU MAY 14 2015
.UPDATE...
AVIATION SECTION UPDATED.
&&
.SYNOPSIS...
ISSUED AT 342 PM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1006 PM EDT THU MAY 14 2015
RADAR LATE THIS EVENING SHOWS A WAVE OF SHOWERS OVER NORTHWEST
CENTRAL INDIANA PUSHING NORTHEAST. MEANWHILE THE REST OF CENTRAL
INDIANA WAS PRECIP FREE...AS WAS THE FLOW UPSTREAM. THUS HAVE
DROPPED POPS OFF FOR THE NEXT FEW HOURS ACROSS MUCH OF THE
FORECAST AREA AS THE WAVE TO THE NORTHWEST BRUSHES BY OUR FORECAST AREA.
HAVE RAMPED POPS BACK UP TO THE LOW CHC CATEGORY AFT 06-07Z..AS
THE HRRR AND GFS SUGGEST SOME SATURATION ACROSS CENTRAL INDIANA IN
ASSOCIATION WITH THE PASSING WAVE. CONFIDENCE IS LOW WIT THIS
FEATURE ANY ANY PRECIP AMOUNT SHOULD BE QUITE LIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 342 PM EDT THU MAY 14 2015
AS PREVIOUSLY MENTIONED IN THE ABOVE NEAR TERM DISCUSSION...THIS
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING. EVENTUALLY
SOME RIDGING ALOFT WILL REESTABLISH ITSELF. THEN THERE IS GOOD
POTENTIAL FOR THE REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY
AFTERNOON WITHIN THIS INCREASINGLY MOIST...WARM...AND UNSTABLE
AIRMASS ACROSS CENTRAL INDIANA. HAVE MAINTAINED SCATTERED POPS FOR
THIS TIME PERIOD AS WELL. SEVERE STORMS ARE NOT ANTICIPATED BUT IF
AND WHEN STRONGER STORMS DEVELOP THEY WILL HAVE THE POTENTIAL TO
PRODUCE HAIL...VERY HEAVY RAINFALL (PER FORECAST PWATS) IN
ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING.
AS FOR THE REST OF THIS PERIOD CENTRAL INDIANA CAN EXPECT TO SEE
MORE OF THE SAME WITH WARM HUMID CONDITIONS AS GULF MOISTURE
LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT THIS WEEKEND
WILL BE LARGELY DEPENDENT ON AVAILABLE INSTABILITY. CONSIDERING
LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES
NOT WARRANT ANY HIGHER THAN 40 TO 70 POPS AT THIS POINT IN TIME.
ALSO...THIS WEEKEND WILL NOT BE A TOTAL WASHOUT BUT WILL CONTINUE TO
CARRY EITHER SCATTERED OR LIKELY SHOWERS AND THUNDERSTORMS FOR
ON/OFF PERIOD THROUGH THE WEEKEND.
IN TERMS OF TEMPERATURES...GUIDANCE IS IN AGREEMENT SO DID NOT
NEED TO MAKE MANY CHANGES AND GENERALLY USED A BLEND FOR
SUMMERTIME LIKE HIGHS IN THE LOW 80S. LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 205 PM EDT THU MAY 14 2015
ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO SUGGEST A WARM AND
UNSETTLED START TO THE EXTENDED.
THE DETERMINISTIC 12Z GFS AND 00Z ECMWF ALONG WITH THE ENSEMBLE
MEANS ARE IN VERY GOOD AGREEMENT REGARDING THE SYNOPTIC PATTERN FOR
THE EXTENDED. THEY LIFT AN UPPER LOW...CURRENTLY OFF THE CALIFORNIA
COAST...NORTHEAST TO ONTARIO ON MONDAY. THIS WILL ALLOW A FRONTAL
SYSTEM TO SWEEP SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY. THE
FRONT WILL INTERACT WITH WARM...MOIST AND UNSTABLE AIR AND TRIGGER
SCATTERED TO NUMEROUS THUNDERSTORMS SUNDAY NIGHT AND MONDAY...BEFORE
COOLER AND DRY WEATHER RETURN UNDER THE INFLUENCE OF STRONG HIGH
PRESSURE BUILDS IN FROM THE WEST. REGIONAL BLEND POPS HANDLE THIS
WELL WITH GOOD CHANCE POPS SUNDAY NIGHT INTO MONDAY AND DRY BY
MONDAY NIGHT. TO WRAP UP THE EXTENDED...A WEAK SOUTHERN SYSTEM COULD
BRING A FEW SHOWERS OR STORMS TO THE AREA BY NEXT THURSDAY.
TEMPERATURES SHOULD START OFF ABOVE NORMAL AHEAD OF THE COLD FRONT
AND THEN FALL TO BELOW NORMAL BEHIND THE FRONT WITH HIGHS ONLY IN
THE 60S LOOKING GOOD BY TUESDAY PER THE REGIONAL BLEND.
&&
.AVIATION /DISCUSSION FOR THE 03Z IND TAF UPDATE/...
VFR CONDITIONS WILL CONTINUE THE NEXT SEVERAL HOURS AS MID LEVEL
CLOUD CONTINUES TO STREAM ACROSS THE TAF SITES AHEAD OF THE
APPROACHING WARM FRONT.
ONGOING TAFS HANDLE THIS WELL AND ONLY MINOR ADJUSTMENTS MADE.
PREVIOUS DISCUSSION BELOW
/DISCUSSION FOR THE 15/00Z TAFS/...
ISSUED AT 700 PM EDT THU MAY 14 2015
VFR THROUGH MUCH OF THE PERIOD OUTSIDE OF ANY POTENTIAL SPOTTY
SHOWERS OVERNIGHT INTO FRIDAY.
CLOUD COVER GENERALLY AROUND 10KFT OVERNIGHT BUT GRADUALLY LOWERING
LATE AND INTO FRIDAY. NO VISIBILITY ISSUES ANTICIPATED OUTSIDE OF
PRECIPITATION.
WINDS WILL BE 10KT OR LESS OUT OF THE SOUTHEAST OVERNIGHT...BECOMING
10 PLUS KNOTS TOMORROW MID MORNING GUSTING AS HIGH AS AROUND
20KT...OUT OF THE SOUTHWEST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...PUMA
SHORT TERM...SMF
LONG TERM...MK
AVIATION...NIELD/JP
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FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1006 PM EDT THU MAY 14 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 342 PM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1006 PM EDT THU MAY 14 2015
RADAR LATE THIS EVENING SHOWS A WAVE OF SHOWERS OVER NORTHWEST
CENTRAL INDIANA PUSHING NORTHEAST. MEANWHILE THE REST OF CENTRAL
INDIANA WAS PRECIP FREE...AS WAS THE FLOW UPSTREAM. THUS HAVE
DROPPED POPS OFF FOR THE NEXT FEW HOURS ACROSS MUCH OF THE
FORECAST AREA AS THE WAVE TO THE NORTHWEST BRUSHES BY OUR FORECAST AREA.
HAVE RAMPED POPS BACK UP TO THE LOW CHC CATEGORY AFT 06-07Z..AS
THE HRRR AND GFS SUGGEST SOME SATURATION ACROSS CENTRAL INDIANA IN
ASSOCIATION WITH THE PASSING WAVE. CONFIDENCE IS LOW WIT THIS
FEATURE ANY ANY PRECIP AMOUNT SHOULD BE QUITE LIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 342 PM EDT THU MAY 14 2015
AS PREVIOUSLY MENTIONED IN THE ABOVE NEAR TERM DISCUSSION...THIS
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING. EVENTUALLY
SOME RIDGING ALOFT WILL REESTABLISH ITSELF. THEN THERE IS GOOD
POTENTIAL FOR THE REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY
AFTERNOON WITHIN THIS INCREASINGLY MOIST...WARM...AND UNSTABLE
AIRMASS ACROSS CENTRAL INDIANA. HAVE MAINTAINED SCATTERED POPS FOR
THIS TIME PERIOD AS WELL. SEVERE STORMS ARE NOT ANTICIPATED BUT IF
AND WHEN STRONGER STORMS DEVELOP THEY WILL HAVE THE POTENTIAL TO
PRODUCE HAIL...VERY HEAVY RAINFALL (PER FORECAST PWATS) IN
ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING.
AS FOR THE REST OF THIS PERIOD CENTRAL INDIANA CAN EXPECT TO SEE
MORE OF THE SAME WITH WARM HUMID CONDITIONS AS GULF MOISTURE
LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT THIS WEEKEND
WILL BE LARGELY DEPENDENT ON AVAILABLE INSTABILITY. CONSIDERING
LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES
NOT WARRANT ANY HIGHER THAN 40 TO 70 POPS AT THIS POINT IN TIME.
ALSO...THIS WEEKEND WILL NOT BE A TOTAL WASHOUT BUT WILL CONTINUE TO
CARRY EITHER SCATTERED OR LIKELY SHOWERS AND THUNDERSTORMS FOR
ON/OFF PERIOD THROUGH THE WEEKEND.
IN TERMS OF TEMPERATURES...GUIDANCE IS IN AGREEMENT SO DID NOT
NEED TO MAKE MANY CHANGES AND GENERALLY USED A BLEND FOR
SUMMERTIME LIKE HIGHS IN THE LOW 80S. LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 205 PM EDT THU MAY 14 2015
ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO SUGGEST A WARM AND
UNSETTLED START TO THE EXTENDED.
THE DETERMINISTIC 12Z GFS AND 00Z ECMWF ALONG WITH THE ENSEMBLE
MEANS ARE IN VERY GOOD AGREEMENT REGARDING THE SYNOPTIC PATTERN FOR
THE EXTENDED. THEY LIFT AN UPPER LOW...CURRENTLY OFF THE CALIFORNIA
COAST...NORTHEAST TO ONTARIO ON MONDAY. THIS WILL ALLOW A FRONTAL
SYSTEM TO SWEEP SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY. THE
FRONT WILL INTERACT WITH WARM...MOIST AND UNSTABLE AIR AND TRIGGER
SCATTERED TO NUMEROUS THUNDERSTORMS SUNDAY NIGHT AND MONDAY...BEFORE
COOLER AND DRY WEATHER RETURN UNDER THE INFLUENCE OF STRONG HIGH
PRESSURE BUILDS IN FROM THE WEST. REGIONAL BLEND POPS HANDLE THIS
WELL WITH GOOD CHANCE POPS SUNDAY NIGHT INTO MONDAY AND DRY BY
MONDAY NIGHT. TO WRAP UP THE EXTENDED...A WEAK SOUTHERN SYSTEM COULD
BRING A FEW SHOWERS OR STORMS TO THE AREA BY NEXT THURSDAY.
TEMPERATURES SHOULD START OFF ABOVE NORMAL AHEAD OF THE COLD FRONT
AND THEN FALL TO BELOW NORMAL BEHIND THE FRONT WITH HIGHS ONLY IN
THE 60S LOOKING GOOD BY TUESDAY PER THE REGIONAL BLEND.
&&
.AVIATION /DISCUSSION FOR THE 15/00Z TAFS/...
ISSUED AT 700 PM EDT THU MAY 14 2015
VFR THROUGH MUCH OF THE PERIOD OUTSIDE OF ANY POTENTIAL SPOTTY
SHOWERS OVERNIGHT INTO FRIDAY.
CLOUD COVER GENERALLY AROUND 10KFT OVERNIGHT BUT GRADUALLY LOWERING
LATE AND INTO FRIDAY. NO VISIBILITY ISSUES ANTICIPATED OUTSIDE OF
PRECIPITATION.
WINDS WILL BE 10KT OR LESS OUT OF THE SOUTHEAST OVERNIGHT...BECOMING
10 PLUS KNOTS TOMORROW MID MORNING GUSTING AS HIGH AS AROUND
20KT...OUT OF THE SOUTHWEST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...PUMA
SHORT TERM...SMF
LONG TERM...MK
AVIATION...NIELD
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
735 PM EDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 355 PM EDT THU MAY 14 2015
A RIDGE OF HIGH PRESSURE WILL SLOWLY SHIFT EAST THROUGH EARLY THIS
EVENING AS AN UPPER LEVEL DISTURBANCE MOVES NORTHEAST OUT OF THE
CENTRAL PLAINS TO THE WESTERN GREAT LAKES. MOISTURE WILL SPREAD
NORTH ACROSS THE AREA...INCREASING THE CHANCES FOR SHOWERS AND A
FEW THUNDERSTORMS STARTING TONIGHT. MORE SHOWERS AND STORMS ARE
POSSIBLE INTO EARLY NEXT WEEK AS ADDITIONAL UPPER LEVEL
DISTURBANCES ASSOCIATED WITH A LARGE SYSTEM OVER THE WEST COAST
MOVE NORTHEAST. LOWS TONIGHT WILL BE IN THE 50S. HIGHS THE NEXT
SEVERAL DAYS WILL RANGE FROM THE MID 70S TO LOWER 80S.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 355 PM EDT THU MAY 14 2015
RAIN CHANCES WILL INCREASE AFTER MIDNIGHT ACROSS THE AREA AS S/W...
CURRENTLY NOTED ACROSS NE MISSOURI PER LATEST W/V IMAGE...TRACKS
TOWARD LAKE MICHIGAN BY 06Z. THIS WAVE WILL GRADUALLY OPEN AS IT
TRACKS JUST NORTH OF THE AREA. W/ THE BEST MID/UPPER FORCING NORTH
OF THE AREA OVERNIGHT...HELD ON WITH CHANCE POPS THROUGH 12Z...AND
SLIGHTLY SLOWED DOWN THE ARRIVAL OF THE POPS. PUSHED BACK THE
HIGHEST POPS TO BETWEEN THE 09Z TO 15Z TIMEFRAME...AS LOW LEVEL JET
NOSES INTO THE WESTERN PART OF THE AREA...W/ A PUSH OF HIGHER
925MB/850MB THETA E. KEPT WITH A SLIGHT CHANCE OF THUNDER EXPANDING
ACROSS THE AREA AFTER 06Z...W/ ELEVATED INSTABILITY UP TO 500 J/KG
ADVECTING ACROSS THE AREA. LITTLE/NO CHANGES TO OVERNIGHT LOWS FROM
PREVIOUS FORECAST.
UNCERTAIN PRECIPITATION FORECAST FOR FRIDAY AS AFOREMENTIONED S/W
OPENS AND PUSHES EAST OF THE REGION...W/ LINGERING PRECIP CHANCES
MAINLY ACROSS THE EASTERN PORTIONS OF THE AREA ON FRIDAY. W/ ANY
RELATIVE FORCING EAST OF THE AREA THROUGH THE AFTERNOON...UPPER
RIDGING BUILDS OVER THE REGION. SOUTHWEST FLOW/WAA REGIME AND PARTLY
CLOUDY SKIES IN THE AFTERNOON SHOULD ALLOW TEMPERATURES TO RISE INTO
THE UPPER 70S TO NEAR 80 DEGREES FOR HIGHS. UNSTABLE CONDITIONS ARE
EXPECTED TO DEVELOP...W/ 12Z NAM VALUES IN EXCESS OF 3000 J/KG
MUCAPE AND 0-3KM LAPSE RATES APPROACHING 8 C/KM. HOWEVER...LITTLE TO
NO SHEAR AND NO TRIGGER/FORCING LEAVES CONVECTIVE ACTIVITY IN
QUESTION LATE AFTERNOON. IF THERE IS A SFC TRIGGER IN THE FORM OF AN
OUTFLOW/DIFFERENTIAL HEATING BOUNDARY FROM OVERNIGHT
PRECIPITATION...COULD SEE STORMS FIRE LATE IN THE AFTERNOON DESPITE
MARGINAL MID LVL LAPSE RATES NEAR 5.5-6 C/KM. FOR NOW...KEPT SLIGHT
CHANCE TO CHANCE POPS FROM 18Z TO 00Z FRIDAY. SHARP GRADIENT IN MAX
T GRID FOR FRIDAY...ESPECIALLY ALONG THE TOLL ROAD CORRIDOR. GRIDDED
HIGHS IN THE LOW/MID 70S ACROSS S CENTRAL LWR MI MAY BE TOO COOL IF
OVERNIGHT PRECIP/CONVECTION IS MINIMAL AND/OR LATE MORNING/EARLY
AFTERNOON CLEARING ALLOWS FOR BETTER THAN ANTICIPATED INSOLATION.
HOWEVER...FEEL CONFIDENT WITH UPPER 70S/LOW 80S CURRENTLY GRIDDED
SOUTH OF THE TOLL ROAD CORRIDOR.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 355 PM EDT THU MAY 14 2015
NAM/WRF/SREF WOULD SUGGEST WARM FRONT HANGING UP ALONG/NORTH OF
US-6. LOW LEVEL JET OF 25 TO 30 KTS WILL ADVECT IN PLENTY OF
MOISTURE AND PROVIDE ENOUGH LIFT TO WARRANT AT LEAST CHC POPS IN THE
SAME AREA. SOME ARGUMENT FOR INCREASING FURTHER...BUT WITH EXACT
MESOSCALE SETUP AFTER FRIDAY AFTERNOON/EVE CONVECTION BEING KEY TO
BEST AREA WILL NOT GO OVERBOARD. SLIGHTLY HIGHER POPS (30 VS 40)
WILL RESIDE ACROSS THE NORTH. SEVERAL MODELS THEN LIGHT UP THE WARM
SECTOR SATURDAY AFTERNOON WITH SUFFICIENT INSTABILITY FOR CONVECTION
AS TEMPERATURES CLIMB WELL INTO THE 70S AND POSSIBLY 80S.
A CONVECTIVE COMPLEX WILL LIKELY BE UNDERWAY TO THE WEST SUNDAY
MORNING AND MOVE EAST TOWARDS THE AREA IN ASSOCIATION WITH A
PREFRONTAL TROUGH. CLOUD COVER AHEAD OF THE SYSTEM WILL DICTATE THE
RISK OF SEVERE WEATHER AND COVERAGE OF ANY CONVECTION. AT THIS TIME
WILL HOLD WITH MID TO HIGH END CHC POPS.
DRIER AND COOLER AIR WILL ARRIVE BEHIND THE FRONT AS HIGH PRESSURE
BUILDS IN THROUGH THE REST OF THE PERIOD. SUPERBLEND OF GUIDANCE
WANTS TO PLACE SLGT CHC POPS WEDS NGT/THURS BUT AT THIS POINT
DESPITE MODELS SUGGESTING A BOUNDARY NEARBY THERE IS LITTLE
CONFIDENCE TO MUDDLE UP A DRY FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 727 PM EDT THU MAY 14 2015
REGIONAL RADAR MOSAIC SHOWS AREA OF LIGHT SHOWERS OVER IL LIFTING
NORTHEAST AHEAD OF SHORT WAVE AND ALONG MOISTURE BOUNDARY. LOW
LEVEL JET BEGINNING TO RAMP UP AND THIS SHOULD HELP FOCUS
ADDITIONAL SHOWERS OVERNIGHT. HRRR GENERALLY IN LINE WITH RAP
BRINGING SOME LIGHT PCPN INTO KSBN TOWARD 03Z. LOWER LEVELS
INITIALLY QUITE DRY PER KSBN DEW POINT OF 39 AT 23Z BUT MOISTURE
ADVECTION APPEARS TO QUICKLY SURGE IN THIS EVENING. EXPECT INITIAL
RADAR RETURNS TO SATURATE LOWER LEVELS SOMEWHAT AND ONLY BE A
SPRINKLE OR NO IMPACT SHOWER. DEEPER FORCING AND MOISTURE ARRIVE
BETWEEN 03Z AND 06Z AND SHOULD BE OFF AND ON AT KSBN WITH BORDERLINE
MVFR/VFR CIG AND VIS OVERNIGHT. KFWA WILL REMAIN DISPLACED EAST OF BETTER
FORCING/MOISTURE BUT SOME MODELS HINT AT A WAVE MOVING EAST
OVERNIGHT. STAYED WITH A VCSH FOR NOW AND VFR CONDITIONS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI/NG
SHORT TERM...NG
LONG TERM...FISHER
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS TOPEKA KS
351 AM CDT Wed May 13 2015
.SHORT TERM...(Today and Tonight)
Issued at 350 AM CDT WED MAY 13 2015
Forecast focus is on onset of precip/amnts tonight. Clouds will be
on the increase today as moisture advection in advance of the upper
wave now across SW TX moves northward. Have trimed back onset time
of precip to mainly after 22Z given trends in obs and short term
models so bulk of the day should be dry. Widespread rain and
isolated thunder will occur after 03z tonight as moisture transport
increases ahead of the upper wave. Greatest instability and upper
divergence is fcst to remain south of the area overnight so expect
heaviest rains to remain south of the area however still expect
widespread 0.75 to 1.5 inch amounts given precip efficiency so all
in all the previous fcst looks good in that regard.
.LONG TERM...(Thursday through Tuesday)
Issued at 350 AM CDT WED MAY 13 2015
Showers and thunderstorms should be ongoing Thursday morning as
the shortwave passes across the forecast area. Models are
converging on a similar timing with precip moving off to the
northeast during the afternoon. Because of this have trended POPs
lower in the afternoon expecting subsidence behind the wave
increases. Models indicate warm air advection increasing behind
the rain Thursday. With some sunshine, highs could warm into the
mid 70s. Think this is more likely across central KS. Over
northeast KS where clouds and rain may linger longer into the
afternoon, have highs only in the lower 70s. Think that much of
Thursday night may end up being dry as the shortwave ridge passes
overhead. However the models seem to continue generating sporadic
QPF as the low level jet increases. Additionally the GFS hints at
a weak wave lifting through central KS early Friday morning.
Because of this have held onto some small POPs.
Friday is shaping up to be a little more interesting regarding
severe weather. Models are showing an area of low pressure
deepening over the high plains during the day. This causes the
dryline to mix into north central KS and a weak warm front to set
up mainly north of the forecast area. While the NAM seems to be
overdone with its dewpoints and resultant surface based
instability, there could be 2 to 3000 J/kg of CAPE by the
afternoon. While deep layer shear appears to be marginal, 0-1 KM
shear is progged to increase near the warm front and dryline. The
wild card is whether elevated precip in the morning allows for the
instability to form. This will be something to keep an eye on.
Chances for severe thunderstorms remains for Saturday and Saturday
night as well. The main upper low is expected to being moving out
of the Rockies with a dryline setting up across central KS. An
unstable airmass is likely to remain in place ahead of this dry
line as deep layer shear increases. Again the main question is
whether precip holds off until the afternoon or if there are
storms throughout the day.
Models have trended dry for Sunday as a cold front moves into the
area. This makes some since with the best forcing lifting into the
upper mid west. By Sunday night, cooler and dryer air is expected
to move into the central plains and bring a dry and cooler weather
through Tuesday. Highs Friday through Sunday should be in the
upper 70s to around 80. Temps for Monday and Tuesday are forecast
to be around 70 with the modified surface ridge over the area.
&&
.AVIATION...(For the 06Z TAFs through 06Z Wednesday Night)
Issued at 1145 PM CDT TUE MAY 12 2015
VFR expected through Wednesday afternoon. As showers increase
Wednesday evening, MVFR CIGS or VSBY are possible in the heavier
rain. Otherwise, expect light southeast winds tonight increasing
during the day on Wednesday with gusts to 20 KTS or more during
the afternoon. Forecast winds at low-levels from RAP and NAM would
suggest low-level wind shear is not very likely tonight, and did
not include in TAF.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Omitt
LONG TERM...Wolters
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1150 PM CDT Tue May 12 2015
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Wednesday)
Issued at 320 PM CDT TUE MAY 12 2015
This afternoon a mid-level ridge was stretching northwestward from
the southern U.S. into the Central and High Plains. Water vapor
imagery showed a closed mid-level low moving into northern
California and a weak disturbance present just east of the Baja
Peninsula at the base of the mid-level trough. Surface high pressure
prevailed over the region today and was slowly shifting eastward
this afternoon. With winds becoming more southerly this afternoon
and with mostly sunny skies prevailing, high temperatures were able
to rise into the upper 60s to low 70s. Despite the continued clear
skies, southerly flow overnight will keep temperatures warmer than
last night with lows in the mid/upper 40s.
Models show the weak disturbance near the Baja Peninsula
intensifying and lifting northeastward into Texas, Oklahoma, and
Kansas through the day on Wednesday. This advancing shortwave trough
will push an area of low pressure into the Southern Plains, which
will help to push the high pressure northeastward out of the area
and toward the Great Lakes region. With this surface pattern in
place, a bit of a pressure gradient will develop through the day on
Wednesday with gusty southeasterly winds by the afternoon. This
southerly flow should support modest warm-air advection into the
region with afternoon high temperatures in the low/mid 70s. Models
show the shortwave trough lifting over the area Wednesday night,
with model soundings showing increasing cloud cover by late
morning/early afternoon. The atmospheric profile looks to quickly
saturate across portions of central Kansas by mid/late afternoon
with PWAT values approaching 1.4 inches by early evening so expect
fairly widespread moderate rain showers to lift into the area.
Instability looks to be extremely weak, so only have a mention of
isolated thunder.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 320 PM CDT TUE MAY 12 2015
Wednesday night through Thursday, an upper level trough across
northwest Mexico will lift northeast across the southern and central
plains. The upper level trough will fill as if lifts northeast. A
lee surface trough will deepen across the southern plains. this will
allow deep gulf moisture to be advected northward across eastern KS.
The combination of strong isentropic lift and ascent ahead of the H5
trough axis will cause a large extensive area of moderate rainfall
to develop across eastern KS. The instability is forecasted to be
quite low with MUCAPES of only 50 to 300 J/KG through Thursday
morning. Any isolated to scattered thunderstorms will not be severe.
Precipitable Water is forecast to increase to 1.4 to 1.6 inches
Wednesday night into Thursday morning. The forecast sounding have
saturation from the surface up to nearly 500 mb. The warm rain
process will lead to a prolong period of steady rainfall. QPF
forecasts across the western half of the CWA will be around one inch
with 1 to 1.5 inches of rainfall across the eastern half of the CWA.
Due to the lack of stronger thunderstorms, this looks to be a long
duration rain even of 12 to 15 hours. I`m not expecting flash
flooding but some of the rivers and steams that are near bankfull
may spill over, causing some minor flooding. Low-lying areas and
flood prone areas may also experience some minor flooding. The rain
should move east of the CWA during the late morning hours as the
upper level trough lifts northeast across the upper Midwest.
Insolation during the late afternoon hours should help high
temperatures to warm into the lower to mid 70s.
Thursday night through early Friday, the deeper gulf moisture will
remain in place with weak south-southwesterly flow aloft. I suppose
if a weak vortmax or H5 trough lifts northeast across the area, a
few showers and thunderstorms could develop Thursday night into
Friday morning.
Friday afternoon through Friday night, another intense upper level
trough will dig southeast into the southwestern US. Increasing
southwesterly flow at mid to upper levels and steeper lapse rates
will cause the environment across eastern Kansas to become more
favorable for severe thunderstorms. However, an Elevated Mix Layer
will overspread eastern KS and may cap off any surface based storms
to develop. In western KS, a dryline will provide enough surface
convergence along with ascent ahead of 50 KT jet max to break the
cap and allow supercell thunderstorms to develop. The 12Z NAM
forecast mixes out the dryline into north central and central KS by
00Z SUN. It also shows a weak outflow boundary draped across east
central and northeast KS. The 12Z NAM generates 3,000 to 4,000 J/KG
of MLCAPE across the CWA. If a storm manages to develop along the
triple point along the NE border if would probably become severe.
Both the GFS and ECMWF keep the dryline farther west across west
central KS. The supercells that develop across west central KS will
move east and may congeal into a complex or QLCS through the evening
hours and move into eastern KS. If the line segments of storms
remain severe, then there will be a risk for large hail and damaging
winds Friday night. If the storms weaken the primary hazard would be
heavy rainfall.
Saturday and Saturday night, both the ECMWF and GFS are in good
agreement lifting the southwestern US trough northeast into the
central high plains. Both models show the dryline moving east from
eastern CO into west central KS through the day. A strong H5 jet max
will lift northeast across western and central KS. The surface
convergence ahead of the dryline and ascent ahead of the advancing
trough will allow for scattered thunderstorms develop. The
environment ahead of the dryline will have strong vertical wind
shear and moderate to high instability. Any thunderstorms that
develops ahead of the dryline will become supercellular which will
produce large hail, damaging winds and tornadoes. These supercells
will move northeast into central and north central KS during the
evening hours. Eventually the isolated to scattered supercells will
congeal into one or more QLCSs, where the primary hazard will become
more of a large hail and damaging wind threat through the mid
evening hours and extending into the early morning hours of Sunday.
Sunday, the upper level trough will lift northeast across NE into MN
by 12 Noon on Sunday. The showers and thunderstorms will push east
of the CWA during the mid morning hours. Sunday will turn out to be
a warm and drier day with highs reaching into the lower 80s across
much of the area.
Sunday night and Monday, A weak cold front will push southward
across the CWA. The front will not have much moisture ahead of it,
so I don`t expect showers to develop Sunday night. Monday will be
mostly sunny with highs in the lower 70s.
Monday night and Tuesday, An upper level ridge will amplify across
the plains. A lee surface trough across the central and southern
high plains will deepen through the day. Deeper moisture will begin
to return northward across TX into OK but the rain and thunderstorms
should remain south of KS through the afternoon hours.
&&
.AVIATION...(For the 06Z TAFs through 06Z Wednesday Night)
Issued at 1145 PM CDT TUE MAY 12 2015
VFR expected through Wednesday afternoon. As showers increase
Wednesday evening, MVFR cigs or vsbys are possible in the heavier
rain. Otherwise, expect light southeast winds tonight increasing
during the day on Wednesday with gusts to 20 kts or more during
the afternoon. Forecast winds at low-levels from RAP and NAM would
suggest low-level wind shear is not very likely tonight, and did
not include in TAF.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Hennecke
LONG TERM...Gargan
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
636 PM CDT THU MAY 14 2015
.UPDATE...
UPDATED AVIATION SECTION FOR 00Z TAF ISSUANCE
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 254 PM CDT THU MAY 14 2015
ALTHOUGH MID-LEVEL REGION OF THE RIDGE WEAKENED FURTHER EAST THAN
ANTICIPATED IN THE WAKE OF THE EJECTING SHORTWAVE TROUGH TO THE
NORTH AND NORTHEAST...SUBSIDENCE SHOULD BUILD BACK IN THIS
EVENING WITH A SMALLER AMPLITUDE RIDGE ALOFT. THIS SUBSIDENCE WILL
BE SHORT LIVED AS THE NEXT SHORT WAVE ROTATING OUT OF THE ROCKIES
MOVES INTO THE WFO PAH FORECAST AREA BY FRIDAY MORNING. ATTEMPTED
TO DEPICT THE MINIMA ON POPS AND WEATHER IN THE GRIDS THIS
EVENING...FOLLOWED BY A SMALL CHANCE OF RAIN CLOSER TO DAYBREAK
AHEAD OF A WEAK LOW/MID LEVEL TROUGH AXIS EMBEDDED IN A MEAN
SOUTHWEST FLOW ALOFT.
FROM FRIDAY THROUGH SATURDAY NIGHT...A TRAIN OF SMALL AND
TRANSIENT SHORTWAVE IMPULSES WILL WORK THROUGH THE WFO PAH
FORECAST AREA. THE VARIABILITY IS GOING TO MAKE IT DIFFICULT TO GO
MUCH BEYOND CHANCE CATEGORY THROUGH FRIDAY NIGHT. THE INFLUENCE
WILL INITIALLY BE DIURNAL...BUT WEAK FORCING WILL DOMINATE
SATURDAY AND SATURDAY NIGHT IN THE WARM CONVEYOR BELT.
HOWEVER...THE POP SIGNAL GETS MORE PERSISTENT SATURDAY AND
SATURDAY NIGHT OVER EXTREME SOUTHERN ILLINOIS...MOST OF WEST
KENTUCKY AND SOUTHEAST MISSOURI...AS THE MEAN ISENTROPIC LIFT
ZONE REMAINS FOCUSED ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST.
CHANNELED VORTICITY ORIENTED PARALLEL TO THE UPPER FLOW WILL
MAINTAIN INTERMITTENT RAIN ACTIVITY THROUGH THE PERIOD.
LEANED CLOSER TOWARD THE HIGHER RESOLUTION NAM-WRF DETERMINISTIC
AND ENSEMBLE GUIDANCE...INCLUDING THE HRRR IN THE 06-18 HOUR TIME
FRAME...WITH MORE EMPHASIS TOWARD THE ECMWF AND CANADIAN GUIDANCE
TOWARD SATURDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 254 PM CDT THU MAY 14 2015
00Z OPS MODELS AND EC/GFS ENSEMBLE MEAN SOLUTIONS REMAINED IN GOOD
AGREEMENT WITH THE OVERALL UPPER AIR PATTERN. AT THE BEGINNING OF
THE PERIOD...A MID LEVEL TROF WILL EJECT NEGATIVE TILT FROM THE
PLAINS INTO THE UPPER MIDWEST SUNDAY. FRONT STILL OFF TO OUR WEST
BUT WITH MOISTURE AND INSTABILITY PRESENT IN AN UNSETTLED SW FLOW
ALOFT...CONTINUED WITH HIGH CHANCE POPS FOR CONVECTION. CONFIDENCE
REMAINS ABOVE AVERAGE.
FRONT WILL SETTLE SOUTH INTO THE AREA LATE SUNDAY NIGHT INTO MONDAY.
LIKELY POPS SUNDAY NIGHT AND ESPECIALLY ACROSS THE SE 2/3 OF THE
CWFA PER THE LATEST OUTPUT. WILL LINGER POPS MONDAY AS THE FRONT
WILL CONTINUE TO PROGRESS SOUTHEAST ACROSS THE AREA. DIMINISHING
POPS MONDAY EVENING...AND IT SHOULD BE DRY AFTER MIDNIGHT MONDAY
NIGHT.
HIGH PRESSURE SHOULD RESULT IN DRY WEATHER TUESDAY THROUGH TUESDAY
NIGHT. THE OVERALL MID LEVEL FLOW PATTERN FLATTENS OUT ACROSS THE
MID CONUS WITH A TROF OFF THE PACIFIC COAST AND OVER SE CANADA. THE
GFS/ECMWF SOLUTIONS OF THE PAST DAY OR SO SUGGEST MODEST MID LEVEL
SUPPORT AND MOISTURE MAY RESULT IN A FEW SHOWERS WEDNESDAY. THURSDAY
IS MORE UNCLEAR. THE MODELS SHOW DECREASING MOISTURE WITH HIGH
PRESSURE TRYING ONCE AGAIN TO BUILD SOUTHEAST. SO NO POPS FOR NOW
THURSDAY.
THE NEW ECMWF GUIDANCE TRENDED A BIT COOLER FOR MONDAY THROUGH
WEDNESDAY. OTHERWISE A CONSENSUS OF THE GFS/GFS ENSEMBLE MOS AND
PREVIOUS ECMWF NUMBERS WERE STEADY. WILL CONTINUE TO MONITOR THIS
TREND. FOR NOW...JUST SLIGHT ADJUSTMENTS TO OUR EXISTING NUMBERS AND
THE OVERALL MOS CONSENSUS FROM THE PAST 48 HOURS.
&&
.AVIATION...
ISSUED AT 636 PM CDT THU MAY 14 2015
VFR CONDITIONS WILL CONTINUE THROUGH THIS TAF PERIOD. MID LEVEL
CLOUDS EARLY THIS EVENING WILL CLEAR OUT...YIELDING LOTS OF CLEAR
SKY OVERNIGHT. THERE MAY BE A FEW SPRINKLES COMING FROM THE MID
CLOUDS. ON FRIDAY...MID AND HIGH CLOUDS WILL BE RATHER EXTENSIVE.
SOME DIURNAL CUMULUS CLOUDS WILL FORM AS MOISTURE INCREASES ON SOUTH
WINDS. THERE WILL LIKELY BE SCATTERED SHOWERS AND STORMS IN THE
AFTERNOON. WHEN THE TIMING AND LOCATION OF THIS ACTIVITY BECOMES
MORE CERTAIN...THEY WILL LIKELY BE ADDED TO ONE OR MORE TAFS.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...CN
AVIATION...MY
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
843 PM MDT THU MAY 14 2015
.UPDATE...
SHOWERS AND A FEW EMBEDDED AND WEAK THUNDERSTORMS ARE MOVING NORTH
OUT OF WYOMING WITH A WEAK SHORTWAVE THIS EVENING. WE USED RECENT
RADAR TRENDS AND RAP AND HRRR SIMULATIONS TO MODIFY OVERNIGHT POPS
TO FIT THESE TRENDS...WHICH MAINLY MEANT INCREASING THEM ALONG A
RYEGATE TO BILLINGS AND SHERIDAN LINE. EXTRAPOLATION OF THE BACK
EDGE OF THE ACTIVITY SUGGESTS THE BRUNT OF IT WILL LIFT NORTHWARD
PAST BILLINGS BETWEEN MIDNIGHT AND 2 AM MDT...AND END UP ALONG A
LINE FROM ROUNDUP TO FORSYTH AND BROADUS BY THAT POINT. THE REST
OF THE FORECAST IS GENERALLY ON TRACK...THOUGH WE DID ADD PATCHY
FOG OVER WESTERN PARTS OF SOUTH CENTRAL MT FROM LATE TONIGHT INTO
FRIDAY MORNING WHERE EASTERLY...UPSLOPE LOW-LEVEL FLOW BEHIND THE
SHOWER ACTIVITY COULD PROMOTE SOME FOG NEAR THE HIGHER TERRAIN.
SCHULTZ
&&
.SHORT TERM...VALID FOR FRI AND SAT...
THE GIST OF THE FORECAST REMAINS THE SAME AS THE PREVIOUS
FORECAST. ONLY CHANGES WERE TO ADJUST POPS UP OR DOWN IN VARIOUS
AREAS DUE TO THE LATEST MODEL CONSENSUS. MODELS CONTINUED TO BE
SIMILAR WITH THE OVERALL PATTERN THROUGH SAT NIGHT...BUT DIFFERED
IN DETAILS OF THE QPF AMOUNTS AND PLACEMENT. HOWEVER...THERE WAS
STILL GOOD AGREEMENT ON THE POTENTIAL FOR HEAVY RAIN OVER
DIFFERENT AREAS EACH PERIOD.
ELONGATED UPPER LOW WAS SEEN IN WATER VAPOR IMAGERY SPINNING
ALONG THE CA COAST THIS AFTERNOON. THIS SYSTEM WILL MOVE E THROUGH
FRI...PLACING GOOD UPPER DIFFLUENCE OVER THE FORECAST AREA. JET
DIVERGENCE WILL BE OVER THE AREA AS WELL. Q-VECTOR CONVERGENCE
WILL INCREASE FROM THE S ON FRI AND A SE LOW-LEVEL JET WILL
CONTINUE TO PUMP MOISTURE INTO THE AREA. A FEW THUNDERSTORMS HAVE
DEVELOPED OVER AND NEAR THE SOUTHERN MOUNTAINS THIS AFTERNOON...IN
LINE WITH THE 500 J/KG SURFACE CAPES SHOWN ON MESOANALYSIS AND
PREDICTED BY THE SREF. DUE TO THE STRONG LIFT AND STEEP MID AND
UPPER LEVEL LAPSE RATES...WILL KEEP A MENTION OF THUNDER IN THE
FORECAST THROUGH FRI. PRECIPITATION WILL OVERSPREAD THE AREA FROM
SW TO NE TONIGHT AND WILL BE LIKELY OVER THE AREA ON FRI.
ON FRI NIGHT...THE LEFT FRONT QUADRANT OF THE JET ROUNDING THE
BASE OF THE SYSTEM WILL PROVIDE LIFT OVER THE AREA. THE UPPER LOW
WILL ELONGATE N INTO THE AREA SUPPORTING STRONG Q-VECTOR
CONVERGENCE. THE FLOW ALOFT WILL TURN WESTERLY OVERNIGHT AND
DYNAMIC COOLING WILL ALLOW 700 MB TEMPERATURES TO DROP BELOW ZERO
DEGREES C...SUPPORTING SOME MOUNTAIN SNOW ACCUMULATION. MODELS HAD
VARIOUS POSSIBILITIES FOR DRY-SLOTTING OVER PORTIONS OF THE
AREA...SO TOOK THIS INTO ACCOUNT FOR THE POP FORECAST. A FEW
INCHES OF SNOW ARE POSSIBLE IN THE BEARTOOTHS/ABSAROKAS.
THE UPPER LOW WILL SHIFT SLOWLY E THROUGH SAT NIGHT AND A COLD
FRONT WILL MOVE SE THROUGH THE AREA ON SAT. STEEP MID AND UPPER
LEVEL LAPSE RATES WILL SUPPORT POSSIBLE THUNDER S AND E OF KBIL.
WENT WITH SCATTERED TO LIKELY POPS FOR SAT AND SAT NIGHT. 850 MB
TEMPERATURES WILL STAY ABOVE ZERO DEGREES C...SO SNOW IS NOT
EXPECTED OVER THE PLAINS. A FEW INCHES OF SNOW ARE EXPECTED OVER
THE MOUNTAINS...AS THE AIRMASS WILL BE TOO WARM TO SUPPORT
SIGNIFICANT ACCUMULATIONS.
HIGHS IN THE 50S ARE EXPECTED BOTH DAYS...WITH 60S AHEAD OF THE
FRONT ON SAT. ARTHUR
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
A BLUSTERY END TO THE WEEKEND IS STILL EXPECTED WITH SOME
IMPROVEMENT BY MONDAY BEFORE ANOTHER SYSTEM APPROACHES THE
FORECAST AREA EARLY NEXT WEEK. THE UPPER LOW AND SURFACE LOW THAT
WILL BRING THE RAIN TO OUR FORECAST AREA TONIGHT INTO SATURDAY ARE
EXPECTED TO SHIFT EAST INTO NORTH DAKOTA DURING THE DAY SUNDAY.
THIS WILL START A DRYING TREND FROM WEST TO EAST DURING THE DAY.
MOISTURE FROM THE CENTRAL AND NORTHERN PLAINS WILL WRAP-AROUND
THESE LOWS AND BACK INTO THE EASTERLY HALF OF MONTANA SUNDAY WITH
THE HIGHEST CHANCES FOR RAIN TO BE ACROSS OUR EASTERN COUNTIES.
PRESSURE GRADIENTS WILL BE TIGHT ACROSS THE CENTRAL AND ESPECIALLY
THE EASTERN AREAS RESULTING IN VERY GUSTY NORTH/NORTHEAST WINDS ON
THE BACK SIDE OF THE LOW. TEMPERATURES WILL BE BELOW NORMAL...AND
THIS COMBINED WITH SHOWERS WILL MAKE FOR A BLUSTERY "COLD" DAY.
700MB TEMPERATURES WILL SUPPORT SNOW FOR THE MOUNTAINS BUT THE
BULK OF THE PRECIP LOOKS TO STAY OUT ACROSS THE PLAINS.
MONDAY LOOKS TO BE DRY WITH A SLIGHT MODERATION IN TEMPERATURES.
THIS WILL BE SHORT-LIVED AS ANOTHER STORM SYSTEM GETS ORGANIZED
ACROSS THE CENTRAL ROCKIES TUESDAY AND WEDNESDAY. AT THIS
TIME...MODELS KEEP MOST OF THE PRECIP SOUTH OF OUR FORECAST AREA
ACROSS WYOMING AND COLORADO. HOWEVER...AS IS THE CASE WITH THESE
UPPER LOWS THIS TIME OF YEAR...MODELS HAVE A HARD TIME THIS FAR
OUT WITH THEIR TRAJECTORY. HOOLEY
&&
.AVIATION...
A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS FROM LIVINGSTON...TO
BILLINGS...TO SHERIDAN WILL CONTINUE TO MOVE NORTH AND EAST
OVERNIGHT. BRIEF IFR CONDITIONS ARE POSSIBLE IN HEAVIER RAINFALL.
MVFR TO IFR CEILINGS ARE EXPECTED AGAIN AFTER THE RAINFALL
OVERNIGHT...BUT SHOULD CLEAR OUT AROUND MID MORNING TOMORROW.
CURRENT GUIDANCE HAS THE LOWEST CEILINGS FROM BILLINGS...TO
ROUNDUP AND OVER TO HARLOWTON. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 048/056 045/052 041/052 038/058 041/056 041/056 042/059
87/T 87/W 66/W 12/W 23/W 45/W 53/W
LVM 044/056 041/053 038/054 035/057 038/055 038/058 037/058
57/T 87/W 66/W 23/T 33/W 44/W 43/W
HDN 048/060 046/055 041/052 035/061 041/059 041/058 040/063
77/T 76/T 66/W 12/W 23/W 55/W 42/W
MLS 046/058 047/058 041/052 035/058 039/058 040/059 040/062
57/T 86/T 66/W 11/B 13/W 44/W 42/W
4BQ 047/058 046/063 042/049 032/058 039/055 039/056 039/060
67/T 64/T 67/W 11/B 23/W 66/W 43/W
BHK 042/058 045/064 040/049 031/055 036/054 037/056 037/060
27/T 93/T 56/W 11/B 13/W 44/W 42/W
SHR 045/061 042/058 039/050 034/058 039/056 038/056 037/058
87/T 54/T 67/W 22/T 44/W 66/W 43/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
916 AM MDT WED MAY 13 2015
.UPDATE...
NO UPDATE PLANNED THIS MORNING. HRRR/WRF INITIALIZED WELL WITH
MORNING PRECIPITATION WHICH WAS LOCATED OVER N MT/E WY. MODELS
SHOWED CONVECTION DEVELOPING OVER THE NE BIG HORNS/PRYORS AND
SPREADING NORTHWARD WITH TIME. OTHER CONVECTION WILL MOVE N FROM E
WY INTO THE AREA. NOT SURE HOW MUCH DEVELOPMENT WILL OCCUR W OF
KBIL THROUGH 18Z...BUT WILL LEAVE THE SLIGHT CHANCE ALONE FOR NOW.
SREF AND RAP SOUNDINGS SHOWED SURFACE CAPES AROUND 500 J/KG ACROSS
MUCH OF THE AREA THIS AFTERNOON AND EVENING...WITH CAPES POSSIBLY
REACHING AS HIGH AS 1000 J/KG. EFFECTIVE BRN SHEAR WILL BE ON THE
ORDER OF 30 TO 40 KT WHICH IS MARGINAL FOR SEVERE STORMS. GIVEN
THE SOMEWHAT HIGH CAPES AND MARGINAL SHEAR...EXPECT ISOLATED
STRONG TO SEVERE STORMS OVER THE AREA THIS AFTERNOON AND EVENING.
HAIL UP TO AN INCH IN DIAMETER WILL BE A THREAT ALONG WITH GUSTY
WINDS...DUE TO INVERTED-V NATURE OF SOUNDINGS. LIFT FOR THE
CONVECTION WILL BE IN THE FORM OF WEAK WAVES...JET
DIVERGENCE...DIFFLUENCE OVER THE W AND TOPOGRAPHY. SLIGHT CHANCE
FOR THUNDERSTORMS WILL LINGER LATE TONIGHT DUE TO STEEP MID-UPPER
LEVEL LAPSE RATES.
MORE SHOWERS AND STORMS ARE EXPECTED THU UNDER AN ACTIVE DIFFLUENT
FLOW. CAPES AND SHEAR WILL BE SIMILAR TO TODAY/S VALUES. ARTHUR
&&
.SHORT TERM...VALID FOR TDY AND THU...
WEATHER CONTINUES TO BECOME MORE ACTIVE AS THE WEEK PROGRESSES AS
A STRONG UPPER LOW OFF THE CALIFORNIA COAST BEGINS ITS APPROACH
ON THE ROCKIES BY LATE IN THE WEEK. ALREADY SEEING SOME SHOWERS
FEEDING NORTH INTO WESTERN AREAS IN MOIST SOUTHWEST FLOW EARLY
THIS MORNING. SO HAVE INCLUDED ISOLATED SHOWERS WEST OF BILLINGS
THIS MORNING. DAYTIME HEATING WILL RESULT IN INCREASED INSTABILITY
BY LATE IN THE DAY...ESPECIALLY ALONG A BOUNDARY/INVERTED TROUGH
FROM ABOUT HARLOWTON TO BILLINGS TO SHERIDAN WHERE HIGHEST CAPES
WERE POOLING. EXPECT THUNDERSTORMS TO DEVELOP IN THIS REGION AIDED
BY AN APPROACHING SHORT WAVE. LOCAL STRONG STORMS LOOK POSSIBLE.
THE STORM PREDICTION CENTER HAS OUTLINED THIS AREA FOR ISOLATED
STORMS CAPABLE OF PRODUCING HAIL CLOSE TO THE ONE INCH SEVERE
LEVELS AND GUSTY WINDS. THIS ACTIVITY EXPECTED TO SHIFT NORTHEAST
INTO THE PLAINS OVERNIGHT...ALTHOUGH WEAKER...BUT KEEPING
PRECIPITATION CHANCES GOING.
FOR THURSDAY...MUCH OF THE SAME EXPECTED...BUT BECOMING EVEN MORE
WIDESPREAD. MORE INSTABILITY TO WORK WITH AGAIN ALONG AND WEST OF
A CORRIDOR FROM HARLOWTON TO BILLINGS TO SHERIDAN. DAYTIME HEATING
WILL AGAIN INCREASE THUNDERSTORM THREAT AND AIDED BY AN INCREASING
DIFFLUENT UPPER FLOW. THIS ACTIVITY AGAIN WILL BE HANGING ON
THROUGH THURSDAY NIGHT AS GOOD SOUTHEASTERLY LOW LEVEL JET
CONTINUES TO FEED MOISTURE INTO THE REGION. FRIEDERS
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS REMAIN IN RELATIVELY GOOD AGREEMENT...WITH REGARD TO
EXTENDED PERIOD OF COOL AND UNSETTLED WEATHER. MODELS ALSO
CONTINUE TO HAVE SOME TIMING AND MINOR TRACK ISSUES...BUT HAVE
ACTUALLY RETURNED TO A DEPICTION OF EVENTS THAT IS VERY SIMILAR TO
RUNS OF 48HRS AGO.
DIFFLUENT FLOW ALOFT IS PROGGED TO PERSIST OVER OUR FORECAST
AREA AHEAD OF THE STRONG PACIFIC LOW PUSHING EASTWARD. THIS WILL
COMBINE WITH A SFC LOW SETTING UP ACROSS NORTHERN WYOMING. THIS
SHOULD RESULT IN A BROAD AREA OF PRECIP ACROSS THE
REGION...THROUGH MUCH OF THE DAY FRIDAY. THE UPPER LEVEL LOW MOVES
NORTHEAST TO SOUTHEAST MONTANA/NORTHEAST WYOMING DURING
SATURDAY...AND BECOMES STACKED WITH SFC LOW...STILL ANCHORED OVER
SOUTHEAST MONTANA...RESULTING IN NUMEROUS WRAP-AROUND TYPE
SHOWERS. MODELS DIVERGE ON TIMING OF PUSHING SYSTEM
EASTWARD...WITH GFS CLEARING SYSTEM EAST INTO THE DAKOTAS ON
SUNDAY MORNING...WHILE THE ECMWF KEEP PRECIP IN THE AREA UNTIL
SUNDAY NIGHT. ECMWF HAS BEEN MORE CONSISTENT OF MODELS THUS
FAR...SO HAVE KEPT HIGH CHANCE POPS IN PLACE THROUGH SUNDAY
AFTERNOON. THERE APPEARS TO BE A BIT OF A BREAK IN PRECIP CHANCES
SUNDAY NIGHT INTO MONDAY...BUT MODELS ARE QUICK TO BRING THE NEXT
TROF INTO THE REGION...WITH SOUTHWEST FLOW ALOFT IMPACTING THE
MOUNTAINS...AND DIFFLUENT FLOW ALOFT QUICKLY SETTING UP OVER THE
REGION MONDAY MORNING. MODELS AGAIN VARY ON HOW THIS SYSTEM CROSS
THE REGION. THE PATH FAVORED BY THE GFS IS VERY SIMILAR TO THE
WEEKEND SYSTEM...WITH CUT OFF LOW SLIDING INTO SOUTHEAST
MONTANA...AND EXITING INTO THE DAKOTAS ON WEDNESDAY AFTERNOON.
ECMWF TAKES A LITTLE MORE TIME FORMING THE CUT OFF LOW...KEEPING
MUCH OF THE PRECIP ALONG THE MT/WY BORDER UNTIL TUESDAY NIGHT. CUT
OFF LOW FORMS TUESDAY NIGHT...AND CATCHES UP TO THE GFS WEDNESDAY
MORNING...SHIFTING THE LOW INTO THE DAKOTAS THAT AFTERNOON. HAVE
CARRIED POPS THAT ARE WELL ABOVE CLIMO THROUGH THIS PERIOD...FROM
MONDAY EVENING THROUGH WEDNESDAY...WITH HIGHEST POPS ACROSS THE
SOUTHERN TIER OF THE CWA.
AS FOR TEMPS...EXPECT TO SEE HIGHS BELOW SEASONAL AVERAGE
THROUGHOUT THE PERIOD. TRENDED TEMPERATURES SLIGHTLY COOLER
THROUGHOUT THE PERIOD...TOWARD THE ECMWF. AGAIN THIS HAS BEEN A
BIT MORE CONSISTENT...AND GFS SEEMS TO BE TRENDING A BIT COOLER AS
WELL. AAG
&&
.AVIATION...
EXPECT A PARTLY TO MOSTLY CLOUDY DAY TODAY WITH ISOLATED SHOWERS
THIS MORNING. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED THIS AFTERNOON ALONG THE MONTANA/WYOMING BORDER...AS WELL
AS ALONG AND WEST OF A KSHR-KBIL-ROUNDUP LINE. MVFR TO IFR
CONDITIONS WILL BE POSSIBLE IN ANY THUNDERSTORM ACTIVITY.
OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGHOUT THE DAY. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 070 046/066 046/058 045/055 043/055 037/060 038/059
2/T 44/T 56/T 66/T 66/W 33/W 34/W
LVM 068 040/064 042/057 040/054 041/054 033/060 034/059
2/T 35/T 56/T 67/T 66/W 33/W 33/W
HDN 073 045/069 046/060 045/058 044/056 035/063 038/061
1/B 53/T 56/T 67/T 76/W 32/W 24/W
MLS 071 046/067 046/062 047/060 044/054 036/061 038/060
1/B 53/T 46/T 88/T 76/W 22/W 23/W
4BQ 070 047/066 047/060 047/058 045/052 034/058 037/059
1/B 32/T 46/T 77/T 76/W 22/W 34/W
BHK 065 043/063 043/059 044/058 044/055 031/060 036/058
1/B 53/T 16/T 88/T 77/W 22/W 24/W
SHR 068 041/067 043/060 042/056 041/052 032/058 035/057
3/T 43/T 56/T 67/T 76/W 23/W 45/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...CORRECTED
NWS NORTH PLATTE NE
656 PM CDT THU MAY 14 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM CDT THU MAY 14 2015
SOUTHERLY LOW LEVEL JET WILL STRENGTHEN ACROSS WESTERN KANSAS MID
TO LATE EVENING...WITH NOSE OF THE JET POINTED AT SOUTHWEST INTO
CENTRAL NEBRASKA. MID LEVELS WILL GRADUALLY DESTABILIZE WITHIN
WARM AIR ADVECTION ZONE ACROSS WESTERN KANSAS INTO MUCH OF
CENTRAL AND WESTERN NEBRASKA OVERNIGHT. AS ISENTROPIC LIFT
INCREASES IN THIS AREA...ESPECIALLY ON NOSE OF LOW LEVEL JET
ACROSS SOUTHWEST NEBRASKA MID TO LATE EVENING...SCATTERED SHOWERS
AND THUNDERSTORMS LIKELY TO RESULT. BUFKIT SOUNDING DATA
INDICATES SOME FAIRLY HEALTHY MID LEVEL CAPE AFTER MIDNIGHT
TONIGHT...ON THE ORDER OF 1500 J/KG...BUT OVERALL SHEAR NOT
GREAT. WOULD EXPECT THAT A FEW STRONGER STORMS COULD PRODUCE SOME
SMALL HAIL...BUT NOT EXPECTING HAIL SIZE TO REACH SEVERE
CRITERIA.
SEVERE WEATHER POTENTIAL CONTINUES TO LOOK PRETTY GOOD FRIDAY
AFTERNOON. SURFACE LOW PRESSURE SHOULD DEEPEN ACROSS NORTHEAST
COLORADO THROUGH THE DAY...WITH A WARM FRONT SHARPENING TO THE
EAST OF THE LOW ACROSS SOUTHWEST NEBRASKA INTO NORTH CENTRAL
KANSAS DURING THE AFTERNOON. TO THE NORTH OF THE SURFACE LOW
ACROSS THE NEBRASKA PANHANDLE...A SURFACE TROUGH WILL BE
ESTABLISHED. MODELS INDICATE THAT OVERALL FORCING MAY BE SOMEWHAT
WEAK AS LARGE SCALE LIFT ASSOCIATED WITH LONG WAVE TROUGH REMAINS
WEST OF THE REGION...NEVERTHELESS SEVERAL WEAK PERTURBATIONS
NOTED WITH SOUTHWEST FLOW ALOFT AHEAD OF THE LARGE SCALE
TROUGHING SHOULD BE ENOUGH TO INITIATE THUNDERSTORMS. TWO AREAS
OF FOCUS EXPECTED FOR CONVECTION FRIDAY AFTERNOON...1) WILL BE
THE SURFACE TROUGH LOCATED ACROSS THE NEBRASKA PANHANDLE...AND 2)
THE WARM FRONT LOCATED ACROSS SOUTHWEST NEBRASKA INTO NORTHERN
KANSAS. STORMS WILL LIKELY BE MOST NUMEROUS ALONG THE SURFACE
TROUGH ACROSS THE PANHANDLE...IN SOMEWHAT CLOSER PROXIMITY TO THE
LARGER SCALE LIFT. MORE ISOLATED STORMS EXPECTED TO DEVELOP NEAR
THE WARM FRONT ACROSS SOUTHWEST NEBRASKA...THESE STORMS WILL BE
IN A BETTER ENVIRONMENT TO PRODUCE SEVERE WEATHER. STRONGER
INSTABILITY WILL COINCIDE WITH GOOD DEEP LAYER SHEAR...AND ANY
STORM THAT DEVELOPS WILL LIKELY BECOME STRONG TO SEVERE.
HODOGRAPHS SUPPORT SPLITTING SUPERCELL POTENTIAL...WITH THE RIGHT
MOVING STORM TO LIKELY DOMINATE. IF STORMS STAY SURFACE BASED
INTO THE EVENING...WHICH THEY LIKELY WILL FOR A TIME...TORNADO
POTENTIAL WILL INCREASE AS BACKED LOW LEVEL FLOW STRENGTHENS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM CDT THU MAY 14 2015
FRIDAY NIGHT STORMS...SOME SEVERE...WILL BE ONGOING/LIFTING
NORTHEAST ACROSS THE AREA. SFC BASED THUNDERSTORMS CONTINUE UNTIL
THE LOSE OF DAYTIME HEATING. CAPE VALUES OF 1500 TO 2000 J/KG AND
ZERO TO 3 KM SHEAR OF 35 TO 45 KTS SHOULD RESULT IN SEVERAL
SUPERCELLS WITH LARGE HAIL AND DAMAGING WINDS THE MAIN
THREAT...ALTHOUGH AN ISOLATED TORNADO IS POSSIBLE. ONCE STORMS
BECOME ELEVATED AS WE COOL THE TORNADO THREAT WILL END.
SATURDAY WILL SEE ANOTHER DISTURBANCE LIFTING ACROSS THE AREA.
STILL HAVE SOME UNCERTAINTIES AS TO HOW THE FRIDAY NIGHT
CONVECTION MAY ALTER THE BOUNDARIES IN PLACE. HOWEVER SHOULD SEE
ANOTHER ROUND OF STORMS FIRE AND LIFT NORTHEAST. THE NE MOVEMENT
MAY RESULT IN SOME TRAINING OF STORMS AND WILL HAVE TO MONITOR
FOR HEAVY RAINFALL. SHEAR IS NOT AS GOOD FOR SATURDAY ALTHOUGH
COULD STILL SEE SOME SEVERE WEATHER.
WEAK COLD FRONT PUSHES THROUGH EARLY SUNDAY AND WILL HELP TO COOL
TEMPS DOWN 5 TO 10 DEGREES. SOME WRAP AROUND MOISTURE FROM
NORTHERN PLAINS LOW MAY IMPACT NORTHERN NEBRASKA.
COOL START TO THE WORK WEEK AS A SECONDARY PUSH OF COLD AIR IS
OVERHEAD. HIGHS MONDAY ONLY IN THE UPPER 50S TO LOWER 60S. A
DEVELOPING STRONG STORM SYSTEM MOVES ACROSS THE WESTERN CONUS. A
DISTURBANCE AHEAD OF THE MAIN LOW MOVES IN FROM THE WEST LATE
MONDAY AND WILL SPARK SOME SHOWERS AND A FEW THUNDERSTORMS.
BY MID WEEK THE LOW PRESSURE SYSTEM WILL PUSH ACROSS THE HIGH
PLAINS. AHEAD OF THE SYSTEM STRONG SOUTHERLY FLOW WILL RETURN
MOISTURE BACK ABOVE 0.75 INCHES...NEARING AN INCH IN SW NEB. COOL
TEMPS /MID 50S TO LOWER 60S/ CONTINUE WITH ACTIVITY TO BE MAINLY
SHOWERS ALTHOUGH BEING MID MAY WILL INCLUDE ISOLATED THUNDER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM CDT THU MAY 14 2015
MAIN FCST CHALLENGE IS TIMING OF TSRA FOR THE KLBF TAF AND
SOUTHERN PORTION OF THE AREA...AND POTENTIAL FOR STRATUS AND BR
FOR THE KVTN TAF SITE OVERNIGHT. FIRST FOR TSRA...ISOLD TSRA HAS
DEVELOPED IN EXTREME SW NEB BUT BELIEVE MORE DEVELOPMENT WILL BE
COMING AS LLJ DEVELOPS IN WRN KS INTO SW NEB TWD MIDNIGHT.
ISENTROIC LIFT IN CONCERT WITH INCREASING ELEVATED INSTABILITY AS
A RESULT OF THE LLJ WILL RESULT IN SCT TSRA DEVELOPMENT AND HAVE
INCLUDED IN KLBF TAF AFTER 06Z. THESE SHOULD MOVE NWD THROUGH THE
NIGHT THOUGH COVERAGE IS A BIT IN QUESTION AS LATEST FEW HRRR RUNS
HAVE SHOWN LIMITED COVERAGE IN SWRN NEB TONIGHT.
NEXT WILL BE POTENTIAL FOR BR/STRATUS OVERNIGHT FURTHER N. STRATUS
CURRENTLY JUST NORTH OF THE NEB/SD BORDER DOES HAVE SWD MOVEMENT
THOUGH ERRODING ON THE WEST SIDE AS INCREASING WRLY MID LEVEL FLOW
CONTINUES. HOWEVER...BELIEVE AFTER SUNSET SHOULD SEE MORE SWD
PROGRESSION AS RAP/NAM SUGGEST AND WOULD BE EXPECTED NORTH OF
DEVELOPING WARM FRONT. HAVE INCLUDED BR IN THE KVTN TAF OVERNIGHT
THOUGH DID NOT TAKE VSBY TO IFR OR BELOW YET. GFS-LAMP ALSO
SUGGEST S THIS SCENARIO...AND THIS IS A BIT OF A CHANGE SINCE THE
LAST TAF FOR KVTN.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...MASEK
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
645 PM CDT THU MAY 14 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM CDT THU MAY 14 2015
SOUTHERLY LOW LEVEL JET WILL STRENGTHEN ACROSS WESTERN KANSAS MID
TO LATE EVENING...WITH NOSE OF THE JET POINTED AT SOUTHWEST INTO
CENTRAL NEBRASKA. MID LEVELS WILL GRADUALLY DESTABILIZE WITHIN
WARM AIR ADVECTION ZONE ACROSS WESTERN KANSAS INTO MUCH OF
CENTRAL AND WESTERN NEBRASKA OVERNIGHT. AS ISENTROPIC LIFT
INCREASES IN THIS AREA...ESPECIALLY ON NOSE OF LOW LEVEL JET
ACROSS SOUTHWEST NEBRASKA MID TO LATE EVENING...SCATTERED SHOWERS
AND THUNDERSTORMS LIKELY TO RESULT. BUFKIT SOUNDING DATA
INDICATES SOME FAIRLY HEALTHY MID LEVEL CAPE AFTER MIDNIGHT
TONIGHT...ON THE ORDER OF 1500 J/KG...BUT OVERALL SHEAR NOT
GREAT. WOULD EXPECT THAT A FEW STRONGER STORMS COULD PRODUCE SOME
SMALL HAIL...BUT NOT EXPECTING HAIL SIZE TO REACH SEVERE
CRITERIA.
SEVERE WEATHER POTENTIAL CONTINUES TO LOOK PRETTY GOOD FRIDAY
AFTERNOON. SURFACE LOW PRESSURE SHOULD DEEPEN ACROSS NORTHEAST
COLORADO THROUGH THE DAY...WITH A WARM FRONT SHARPENING TO THE
EAST OF THE LOW ACROSS SOUTHWEST NEBRASKA INTO NORTH CENTRAL
KANSAS DURING THE AFTERNOON. TO THE NORTH OF THE SURFACE LOW
ACROSS THE NEBRASKA PANHANDLE...A SURFACE TROUGH WILL BE
ESTABLISHED. MODELS INDICATE THAT OVERALL FORCING MAY BE SOMEWHAT
WEAK AS LARGE SCALE LIFT ASSOCIATED WITH LONG WAVE TROUGH REMAINS
WEST OF THE REGION...NEVERTHELESS SEVERAL WEAK PERTURBATIONS
NOTED WITH SOUTHWEST FLOW ALOFT AHEAD OF THE LARGE SCALE
TROUGHING SHOULD BE ENOUGH TO INITIATE THUNDERSTORMS. TWO AREAS
OF FOCUS EXPECTED FOR CONVECTION FRIDAY AFTERNOON...1) WILL BE
THE SURFACE TROUGH LOCATED ACROSS THE NEBRASKA PANHANDLE...AND 2)
THE WARM FRONT LOCATED ACROSS SOUTHWEST NEBRASKA INTO NORTHERN
KANSAS. STORMS WILL LIKELY BE MOST NUMEROUS ALONG THE SURFACE
TROUGH ACROSS THE PANHANDLE...IN SOMEWHAT CLOSER PROXIMITY TO THE
LARGER SCALE LIFT. MORE ISOLATED STORMS EXPECTED TO DEVELOP NEAR
THE WARM FRONT ACROSS SOUTHWEST NEBRASKA...THESE STORMS WILL BE
IN A BETTER ENVIRONMENT TO PRODUCE SEVERE WEATHER. STRONGER
INSTABILITY WILL COINCIDE WITH GOOD DEEP LAYER SHEAR...AND ANY
STORM THAT DEVELOPS WILL LIKELY BECOME STRONG TO SEVERE.
HODOGRAPHS SUPPORT SPLITTING SUPERCELL POTENTIAL...WITH THE RIGHT
MOVING STORM TO LIKELY DOMINATE. IF STORMS STAY SURFACE BASED
INTO THE EVENING...WHICH THEY LIKELY WILL FOR A TIME...TORNADO
POTENTIAL WILL INCREASE AS BACKED LOW LEVEL FLOW STRENGTHENS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM CDT THU MAY 14 2015
FRIDAY NIGHT STORMS...SOME SEVERE...WILL BE ONGOING/LIFTING
NORTHEAST ACROSS THE AREA. SFC BASED THUNDERSTORMS CONTINUE UNTIL
THE LOSE OF DAYTIME HEATING. CAPE VALUES OF 1500 TO 2000 J/KG AND
ZERO TO 3 KM SHEAR OF 35 TO 45 KTS SHOULD RESULT IN SEVERAL
SUPERCELLS WITH LARGE HAIL AND DAMAGING WINDS THE MAIN
THREAT...ALTHOUGH AN ISOLATED TORNADO IS POSSIBLE. ONCE STORMS
BECOME ELEVATED AS WE COOL THE TORNADO THREAT WILL END.
SATURDAY WILL SEE ANOTHER DISTURBANCE LIFTING ACROSS THE AREA.
STILL HAVE SOME UNCERTAINTIES AS TO HOW THE FRIDAY NIGHT
CONVECTION MAY ALTER THE BOUNDARIES IN PLACE. HOWEVER SHOULD SEE
ANOTHER ROUND OF STORMS FIRE AND LIFT NORTHEAST. THE NE MOVEMENT
MAY RESULT IN SOME TRAINING OF STORMS AND WILL HAVE TO MONITOR
FOR HEAVY RAINFALL. SHEAR IS NOT AS GOOD FOR SATURDAY ALTHOUGH
COULD STILL SEE SOME SEVERE WEATHER.
WEAK COLD FRONT PUSHES THROUGH EARLY SUNDAY AND WILL HELP TO COOL
TEMPS DOWN 5 TO 10 DEGREES. SOME WRAP AROUND MOISTURE FROM
NORTHERN PLAINS LOW MAY IMPACT NORTHERN NEBRASKA.
COOL START TO THE WORK WEEK AS A SECONDARY PUSH OF COLD AIR IS
OVERHEAD. HIGHS MONDAY ONLY IN THE UPPER 50S TO LOWER 60S. A
DEVELOPING STRONG STORM SYSTEM MOVES ACROSS THE WESTERN CONUS. A
DISTURBANCE AHEAD OF THE MAIN LOW MOVES IN FROM THE WEST LATE
MONDAY AND WILL SPARK SOME SHOWERS AND A FEW THUNDERSTORMS.
BY MID WEEK THE LOW PRESSURE SYSTEM WILL PUSH ACROSS THE HIGH
PLAINS. AHEAD OF THE SYSTEM STRONG SOUTHERLY FLOW WILL RETURN
MOISTURE BACK ABOVE 0.75 INCHES...NEARING AN INCH IN SW NEB. COOL
TEMPS /MID 50S TO LOWER 60S/ CONTINUE WITH ACTIVITY TO BE MAINLY
SHOWERS ALTHOUGH BEING MID MAY WILL INCLUDE ISOLATED THUNDER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 645 PM CDT THU MAY 14 2015
MAIN FCST CHALLENGE IS TIMING OF TSRA FOR THE KLBF TAF AND
SOUTHERN PORTION OF THE AREA...AND POTENTIAL FOR STRATUS AND BR
FOR THE KVTN TAF SITE OVERNIGHT. FIRST FOR TSRA...ISOLD TSRA HAS
DEVELOPED IN EXTREME SW NEB BUT BELIEVE MORE DEVELOPMENT WILL BE
COMING AS LLJ DEVELOPS IN WRN KS INTO SW NEB TWD MIDNIGHT.
ISENTROIC LIFT IN CONCERT WITH INCREASING ELEVATED INSTABILITY AS
A RESULT OF THE LLJ WILL RESULT IN SCT TSRA DEVELOPMENT AND HAVE
INCLUDED IN KLBF TAF AFTER 06Z. THESE SHOULD MOVE NWD THROUGH THE
NIGHT THOUGH COVERAGE IS A BIT IN QUESTION AS LATEST FEW HRRR RUNS
HAVE SHOWN LIMITED COVERAGE IN SWRN NEB TONIGHT.
NEXT WILL BE POTENTIAL FOR BR/STRATUS OVERNIGHT FURTHER N. STRATUS
CURRENTLY JUST NORTH OF THE NEB/SD BORDER DOES HAVE SWD MOVEMENT
THOUGH ERRODING ON THE WEST SIDE AS INCREASING WRLY MID LEVEL FLOW
CONTINUES. HOWEVER...BELIEVE AFTER SUNSET SHOULD SEE MORE SWD
PROGRESSION AS RAP/NAM SUGGEST AND WOULD BE EXPECTED NORTH OF
DEVELOPING WARM FRONT. HAVE INCLUDED BR IN THE KVTN TAF OVERNIGHT
THOUGH DID NOT TAKE VSBY TO IFR OR BELOW YET. GFS-LAMP ALSO
SUGGEST S THIS SCENARIO...AND THIS IS A BIT OF A CHANGE SINCE THE
LAST TAF FOR KVTN.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...MASEK
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
308 PM CDT WED MAY 13 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
TONIGHT
LATEST SHORT TERM PROGS IN AGREEMENT SHOWING THAT GOING RAINFALL
FCST FOR TONIGHT IS ON TRACK WITH PCPN ACTIVITY DEVELOPING OVER KS
THEN EXPANDING NWD INTO THE CWA EARLY THIS EVENING. GIVEN
COMBINATION OF UPPER SUPPORT VIA POTENT VORT MAX/STRONG DIVG
WORKING IN TANDEM WITH RATHER MOIST 305K UPGLIDE...SEEMS
REASONABLE TO ASSUME THAT SEVERAL LOCATIONS SHOULD SEE RAINFALL
TOTALS OF AT LEAST HALF AN INCH MAINLY OVER THE SRN CWA WHERE
LIFT/MOISTURE WILL BE MORE PREVALENT. IN ADDITION...MODELS ARE
SHOWING INSTABILITY PARAMETERS WILL BE WEAK AT BEST SO ANY TSTM
DEVELOPMENT SHOULD BE ISOLATED.
DEE
THURSDAY THROUGH SATURDAY
TIMING AND POTENTIAL FOR SEVERE STORMS BOTH FRIDAY AND SATURDAY
WILL BE THE MAIN FORECAST CONCERNS.
OUR AREA WILL GENERALLY BE IN SOUTH OR SOUTHWEST MID TROPOSPHERIC
FLOW THE NEXT FEW DAYS. WATER VAPOR IMAGERY EARLY THIS WEDNESDAY
AFTERNOON...IN COMBINATION WITH EARLY AFTERNOON RAP MODEL
INTITIALIZATIONS...SHOWED FAIRLY IMPRESSIVE SHORTWAVE TROUGH FROM
COLORADO DOWN INTO WEST TEXAS. THIS WILL LIFT NORTHEAST ACROSS THE
AREA TONIGHT AND THURSDAY. BRIEF SHORTWAVE RIDGING BUILDS IN FOR
LATE THURSDAY/EARLY THURSDAY NIGHT...WHILE A STRONG CLOSED LOW
DIGS DOWN INTO NEVADA AND CALIFORNIA. GENERAL MODEL CONSENSUS
SHOWS THE CENTER OF THAT 500 MB LOW SHOULD LIFT OUT INTO NORTHEAST
WYOMING OR SOUTHEAST MONTANA BY SATURDAY EVENING.
THURSDAY...SHOWERS WILL LINGER AT LEAST IN THE MORNING...WITH
ISOLATED THUNDER POSSIBLE. CHANCES DECREASE THROUGH THE AFTERNOON.
EXPECT AT LEAST THE SOUTHWEST HALF OF OUR FORECAST AREA TO SEE
SOME AFTERNOON SUNSHINE AND THAT SHOULD HELP PUSH HIGHS INTO THE
70S THERE. AREAS FROM AROUND YANKTON DOWN TO ONAWA...HARLAN AND
RED OAK MAY ONLY TOP OUT FROM 65 TO 70. PCPN AMOUNTS THURSDAY ARE
EXPECTED TO BE MOSTLY UNDER 0.25 INCHES.
A WEAK COLD FRONT WILL SETTLE DOWN INTO THE FORECAST AREA THURSDAY
NIGHT AND THEN STALL. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG
AND NORTH OF THE BOUNDARY THURSDAY NIGHT AS THE LOW LEVEL JET
INCREASES AND CAUSES ISENTROPIC LIFT. BEST FOCUS SEEMS TO BE OVER
SOUTHEAST NEBRASKA.
FRIDAY AND FRIDAY NIGHT WILL BE INTERESTING. SOUTHERLY LOW LEVEL
FLOW INCREASES AS LOW PRESSURE INITIALLY OVER NORTHEAST COLORADO AT
12Z FRIDAY LIFTS NORTH TO WEST/NORTHWEST OF VALENTINE BY 06Z
SATURDAY. HIGHS FRIDAY SHOULD REACH 75 TO 80...PUSHING BOUNDARY
LAYER CAPE VALUES INTO THE 1500 TO 3000 J/KG RANGE. 0-6 KM AGL BULK
SHEAR VALUES SHOULD BE MOSTLY 25-40 KNOTS. STORMS MAY INITIALLY BE
MOSTLY NORTH OF THE FRONT...BUT THEN COULD ALSO DEVELOP IN THE WARM
SECTOR OR FARTHER BACK TO THE WEST IN CENTRAL NEBRASKA LATER IN THE
DAY. DETAILS SHOULD BECOME MORE CLEAR WITH THURSDAY MODEL RUNS ON
THE LOCATION OF FRONTAL BOUNDARIES WHICH WILL HELP FOCUS THE
ACTIVITY IN THE AFTERNOON AND EVENING. STORM COVERAGE MAY DROP OFF
DRASTICALLY AFTER MIDNIGHT.
SATURDAY...OVERALL PARAMETERS ARE EXPECTED TO BE IN PLACE FOR
ANOTHER POSSIBLE SEVERE EVENT...BUT NOT COMPLETELY SOLD ON THAT
SINCE IT WILL AT LEAST SOMEWHAT DEPEND ON WHAT HAPPENS FRIDAY. MID
LEVEL WINDS SHOULD INCREASE AND THEREFORE BULK SHEAR VALUES MAY
END UP HIGHER THAN THOSE FRIDAY. TIMING OF CONVECTION WILL BE THE
KEY.
MILLER
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
STORMS SHOULD LINGER INTO SATURDAY NIGHT...WITH SHOWERS/A FEW
EMBEDDED STORMS POSSIBLE SUNDAY MORNING. THE 12Z GFS WAS MOSTLY
DRY IN OUR AREA SUNDAY...BUT THE 12Z ECMWF WAS ABOUT 6 HOURS
SLOWER LIFTING PCPN OUT OF THE AREA. SO...FOR NOW WE HAVE KEPT
SOME LOW POPS SUNDAY IN OUR NORTHERN ZONES SUNDAY.
SUNDAY NIGHT THROUGH TUESDAY SHOULD BE LESS ACTIVE AS HIGH PRESSURE
BUILDS INTO THE REGION WITH COOL TEMPERATURES. SOME LOWS COULD DROP
DOWN TO NEAR 40. IT APPEARS THAT CHANCES FOR SHOWERS/STORMS WILL
INCREASE AGAIN BY TUESDAY NIGHT AND WEDNESDAY AS SHORTWAVE ENERGY
MOVES IN FROM THE WEST/SOUTHWEST.
MILLER
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1230 PM CDT WED MAY 13 2015
A POTENT UPPER DISTURBANCE COUPLED WITH INCREASING LLVL MOISTURE
WILL TRANSLATE TO CONDITIONS DETERIORATING EARLY THIS EVENING
FROM VFR TO IFR/LIFR. EXPECT PCPN ACTIVITY TO QUICKLY EXPAND NWD
OUT OF KS AND INTO ERN NEB WITH RA PREVAILING THRU TONIGHT AND
INTO EARLY THURSDAY MORNING. INSTABILITY PARAMETERS WILL BE WEAK
AT BEST...AND ANY TSRA DEVELOPMENT WILL BE ISOLATED IN NATURE.
BECAUSE OF THIS...HAVE OPTED TO NOT INCLUDE ANY MENTION OF TS AT
THIS TIME.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE/MILLER
LONG TERM...MILLER
AVIATION...DEE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
302 PM CDT WED MAY 13 2015
.SYNOPSIS...
ISSUED AT 255 PM CDT WED MAY 13 2015
CLOSED LOW MOVING OUT OF THE GULF OF ALASKA AND MOVING INTO THE
COAST OFF THE PACIFIC NORTHWEST. RIDGE FROM THE SOUTHEAST CONUS
INTO THE NORTHERN PLAINS WITH A STRONG UPPER WAVE MOVING OUT OF
THE SOUTHERN ROCKIES ONTO THE CENTRAL PLAINS. RADAR RETURNS
DEVELOPING FROM THE TEXAS PANHANDLE INTO THE EASTERN PLAINS OF
WYOMING AND THE PANHANDLE OF NEBRASKA. WEAK TROUGH THROUGH THE
NORTHEAST CONUS.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 255 PM CDT WED MAY 13 2015
MAIN FORECAST CHALLENGES INVOLVE PRECIPITATION CHANCES TONIGHT AND
INTO THURSDAY MORNING. FAIRLY SIGNIFICANT PV ANOMALY WILL CONTINUE
TO ROTATE NEWD TONIGHT WITH GOOD MOISTURE TRANSPORT AHEAD OF IT.
STRONG SRLY WINDS ADVECTING LOW TO MID 50S DEW POINTS INTO THE
REGION AS WELL. WEAK CONVERGENCE ALONG SFC TROUGH LOCATED IN THE ERN
NEB PANHANDLE STARTING TO ALLOW DEVELOPMENT OF SHRA IN WRN KEITH
COUNTY AND THIS TREND SHOULD CONTINUE AS UPPER FORCING AND
ASSOCIATED MID LEVEL FRONTOGENESIS COMBINE TO TAKE BETTER ADVANTAGE
OF WEAK INSTABILITY ACROSS PORTIONS OF WRN NEB. HOWEVER EFFECTIVE
SHEAR IS MODEST AT BEST...THEREFORE MULTICELL TYPE CONVECTION WOULD
BE EXPECTED...AND ALTHOUGH THERE IS LIMITED INSTABILITY A FEW
UPDRAFTS MAY BE SUSTAINED LONG ENOUGH TO PRODUCE SOME HAIL...THOUGH
WIDESPREAD SEVERE HAIL IS NOT EXPECTED AT THIS TIME. INCREASING
SYNOPTIC SCALE LIFT WILL ALLOW FURTHER SHRA DEVELOPMENT OVERNIGHT
ACROSS KS AND MOVING INTO SRN NEB...BUT STRONG STORMS NOT EXPECTED
GIVEN ONLY LIMITED INSTABILITY ALOFT DURING THE EVENING HOURS. WITH
CURRENT POTENTIAL FOR RIVER FLOODING WE WILL BE WATCHING QPF AMOUNTS
CAREFULLY...BUT CURRENTLY AMOUNTS GENERALLY ONE TENTH TO ONE QUARTER
INCH IS EXPECTED MOST PLACES OVERNIGHT...THOUGH ISOLATED HIGHER
AMOUNTS WILL BE POSSIBLE IN MORE ROBUST TSRA SHOULD THEY DEVELOP.
SHRA MOVES NEWD THROUGH THE LATE EVENING AND OVERNIGHT...AND SOME
POTENTIAL FOR FOG DEVELOPMENT AFTER PRECIP ENDS IN WEAKENING WINDS
TWD MORNING...ESPECIALLY IN SW NEB. CONFIDENCE ON WIDESPREAD FOG
DEVELOPMENT IS LOW SO HAVE HAVE NOT INCLUDED IN GRIDDED FCST BUT WILL
BE WATCHING TO SEE HOW PRECIP EVOLVES.
SUBSIDENCE INCREASES IN THE WAKE OF THE NEWD MOVING PV ANOMALY
DURING THE DAY THURSDAY...THOUGH LINGERING SHRA POSSIBLE IN PORTIONS
OF NORTHERN NEB. WRLY DOWSLOPE WINDS WILL TAKE OVER TO CLEAR SKIES
THROUGH THE AFTERNOON FROM WEST TO EAST AND ALSO ALLOW STRONGER
INSOLATION AND DOWNSLOPE WARMING TO OCCUR. THEREFORE HAVE SIDED WITH
WARMER GUIDANCE FOR MAX TEMPS THURSDAY...BUT TIMING OF CLOUDS
DECREASING WILL BE CRITICAL. TRANSITORY RIDGING DEVELOPS IN BETWEEN
EXITING PV ANOMALY AND MORE IMPRESSIVE PV ANOMALY TO ARRIVE EARLY
FRIDAY MORNING SO A DRYING TREND WAS FOLLOWED THROUGH THURSDAY
AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 255 PM CDT WED MAY 13 2015
MID AND UPPER FEATURES FAIRLY CONSISTENT THROUGH THE MID AND LONG
TERM SOLUTIONS AND HAVE USED A BLEND FOR THE FORECAST WITH GOOD
CONFIDENCE. THURSDAY NIGHT A STATIONARY BOUNDARY WILL LIE ACROSS
THE SANDHILLS ISOLATED THUNDERSTORMS AND SHOWERS WILL DEVELOP OVER
THE NEBRASKA PANHANDLE THROUGH THE EVENING AS THE UPPER LOW TO
THE WEST MOVES EAST. AFTER MIDNIGHT STRONGER MID LEVEL ENERGY TO
MOVE ACROSS WESTERN NEBRASKA WITH THUNDERSTORMS DEVELOPING ALONG
THE BOUNDARY AND SPREADING NORTHEAST THROUGH THE SANDHILLS. FRIDAY
A SURFACE LOW OVER NORTHEAST COLORADO...IN RESPONSE TO UPPER
LOW...WILL DEEPEN THROUGH THE DAY AND A WARM FRONTAL BOUNDARY ALONG
THE KANSAS NEBRASKA BORDER WILL LIFT NORTH THROUGH THE DAY. STEEP
LAPSE RATES AND FAVORABLE HODOGRAPHS ENTIRE FORECAST AREA HAS BEEN
PLACED IN ENHANCED. WARM FRONT LIFTS SLOWLY NORTH AND INTO SOUTH
DAKOTA NEBRASKA BORDER AREA BY 12Z. WARM FRONTAL BOUNDARY WILL
REMAIN FOCUS OF SEVERE WEATHER THROUGHOUT FRIDAY. MODELS HAVE SOME
VARIANCES ON WHERE THIS BOUNDARY MIGHT LIE. HAVE CONTINUED WITH
LIKELY POPS. MOST OF WESTERN NEBRASKA DRY SLOTTED THROUGH THE DAY
ON SATURDAY. WITH GOOD WARM AIR ADVECTION TEMPERATURES RISING INTO
THE 70S BUT SURFACE LOW OVER THE DAKOTAS WILL DRAG A COOL FRONT
EAST ACROSS WESTERN NEBRASKA THROUGH THE DAY INTO THE EVENING. THE
FRONT WILL BE THE FOCUS OF THUNDERSTORM DEVELOPMENT WITH DYNAMICS
SUGGESTING ANOTHER ROUND OF SEVERE WEATHER WITH HAIL THE MAIN
THREAT. RESIDUAL SHOWERS AND TEMPERATURES FALLING INTO THE 60S ON
SUNDAY. MODELS SUGGESTING CANADIAN MODIFIED ARCTIC AIR DIVING INTO
THE NORTHERN PLAINS MONDAY WITH TEMPERATURES FALLING INTO THE 50S
AND 60S AND DRY. ANOTHER NEGATIVELY TILTED CLOSED LOW TO MOVE OUT
OF THE ROCKIES MID WEEK ONTO THE NORTHERN PLAINS WITH ANOTHER
ROUND OF PRECIP.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1250 PM CDT WED MAY 13 2015
MAIN AVIATION FCST CONCERNS REVOLVE AROUND SHRA/TSRA TIMING THIS
AFTERNOON AND EVENING. SFC TROUGH DEVELOPS IN THE PANHANDLE THIS
AFTERNOON IN RESPONSE TO UPPER PV ANOMALY MOVING NEWD IN THE NEXT
24 HRS. SOME INSTABILITY ALOFT IN CONCERT BUT CLOUD COVER WILL
LIMIT FURTHER DESTABILIZATION. HOWEVER...DECENT FGEN SIGNATURE
INDICATED IN IR SAT PICS AND LATEST 700MB RAP ANALYSIS IN NRN CO
SUGGESTS A DEEPER CIRCULATION SHOULD DEVELOP ALONG THE SFC TROUGH
LATER TO ENHANCE TSRA CHANCES THERE. FURTHER EWD...MAINLY SHRA IN
THE EVENING AND OVERNIGHT HOURS WITH LESSER INSTABILITY. DEPENDING
ON TIMING OF SHRA ENDING IN THE KLBF AND KVTN TAF SITES THERE
COULD BE BR DEVELOPMENT DURING THE EARLY MORNING HOURS. ONLY
MODERATE CONFIDENCE IN THIS HOWEVER AS WINDS SHIFT TO SWRLY DURING
MID MORNING. MORE CONFIDENCE IN THE KLBF TAF AND THEREFORE HAVE
INCLUDED FOR A LONGER PERIOD OF TIME. CLEARING SKIES TWD LATE
MORNING /END OF TAF PERIOD/ AS PRECIP MOVES OUT.
&&
.HYDROLOGY...
ISSUED AT 255 PM CDT WED MAY 13 2015
THE RIVER FORECAST WAS TRENDED SLIGHTLY LOWER TODAY FOR ROSCOE AND
BRADY...BUT LEFT AS IS NEAR THE CITY OF NORTH PLATTE. UPSTREAM
RIVER DATA FROM NORTHEASTERN COLORADO DEPICTS A BROAD CREST...WHICH
IS LOWER THAN PREVIOUSLY ANTICIPATED. DESPITE THE DOWNWARD
TREND...IT CANNOT BE STRESSED ENOUGH THAT PERSONS WHO LIVE IN
VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER IN SOUTHWEST NEBRASKA
AND PLATTE RIVER ACROSS EASTERN LINCOLN SHOULD CONTINUE TO PAY CLOSE
ATTENTION TO FLOOD FORECASTS IN THE COMING DAYS AND BE PREPARED TO
TAKE PROPER ACTION IF REQUESTED. FLOOD WARNINGS REMAIN FOR THE SOUTH
PLATTE RIVER FROM THE BORDER OF NORTHEAST COLORADO...EAST THROUGH
LINCOLN COUNTY INTO NEXT WEEK.
THE FLOODING IS A RESULT OF EARLY SNOW MELT IN THE UPPER SOUTH
PLATTE RIVER BASIN AND PREVIOUS HEAVY RAINFALL ACROSS NORTHEASTERN
COLORADO AND WESTERN NEBRASKA. UNCERTAINTY IN THE FORECAST IS
TRENDING LOWER AS THERE IS SUFFICIENT SAMPLING FROM UPSTREAM RIVER
SITES. THAT BEING SAID...MINOR FLUCTUATIONS ARE STILL
POSSIBLE...ESPECIALLY SINCE ADDITIONAL PRECIPITATION IS ANTICIPATED
ACROSS THE REGION LATE THIS AFTERNOON THROUGH THURSDAY AND AGAIN
THIS WEEKEND.
CONFIDENCE IS HIGH IN THAT THIS EVENT WILL NOT EQUAL OR EXCEED
THE RECORD FLOODING EVENT OF SEPTEMBER 2013...BUT RIVER STAGE
FORECASTS WILL CONTINUE TO BE CLOSELY MONITORED AN UPDATED AS
ADDITIONAL UPSTREAM DATA BECOME AVAILABLE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...POWER
SHORT TERM...JWS
LONG TERM...POWER
AVIATION...JWS
HYDROLOGY...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1251 PM CDT WED MAY 13 2015
.UPDATE...
ISSUED AT 1250 PM CDT WED MAY 13 2015
PRECIPITATIOIN CHANCES HAVE BEEN ADJUSTED SOMEWHAT FOR TIMING
BASED ON LATEST CONVECTION ALLOWING MODEL OUTPUT AND CURRENT
TRENDS ON RADAR AND SATELLITE. ECHOES INCREASING IN NERN CO AND
SRN NEB PANHANDLE IN THE LAST HOUR AS MID LEVEL FGEN INCREASING
SOMEWHAT ALONG THE SERN WY NRN CO BORDER. DEEP MOIST CONVERGENCE
INCREASING IN RESPONSE BASED ON SPC MESOANALYSIS GRAPHICS AND ECHO
MOVEMENT HAS BEE GRADUALLY TO THE NORTH...THOUGH SOME SATURATION
OF THE MIDDLE ATMOSPHERE WILL BE NEEDED TO BRING RAIN TO THE
SURFACE. OTHERWISE MAX TEMPS KEEP WHERE THEY WERE EVEN THOUGH
CLOUD COVER WILL PLAY A PART THIS AFTERNOON. WINDS WILL BE
LIGHTEST WHERE SFC TROUGH WIL FURTHER DEVELOP IN THE PANHANDLE
THIS AFTERNOON...BUT STILL QUITE GUSTY FURTHER EAST. RAIN CHANCES
FURTHER INCREASE ACROSS THE REMAINDER OF THE AREA THIS EVENING
THOUGH QPF VALUES IN GENERAL SHOULD RANGE MOSTLY BTWN ONE TENTH TO
ONE QUARTER OF AN INCH WITH LOCALIZED AMOUNTS UP TO ONE HALF INCH
POSSIBLE BY MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED MAY 13 2015
TODAY AND TONIGHT...THE SUBTROPICAL DISTURBANCE OFF OF BAJA MEXICO
YESTERDAY HAS MOVED NORTH INTO NEW MEXICO THIS MORNING. THE MODELS
LIFT THIS DISTURBANCE THROUGH THE CNTL PLAINS TODAY AND TONIGHT.
TWO CONVECTIVE ITEMS OF INTEREST HAVE BEEN IDENTIFIED AS THE
DISTURBANCE MOVES THRU WRN AND NCNTL NEBRASKA LATE THIS AFTN AND
TONIGHT. ONE IS A ROUND OF CONVECTION THAT SHOULD FIRE ON THE
COLORADO FRONT RANGE AND LARAMIE RANGE AROUND 18Z-21Z. THE STEERING
WINDS ALOFT CARRY THIS CONVECTION NNE THROUGH THE NEB PANHANDLE
AFFECTING AREAS MAINLY ALONG AND WEST OF HIGHWAY 61. MEANWHILE THE
SREF AND GEF SUGGEST A SECOND HEAVIER RAIN CENTER WILL MOVE ACROSS
WCNTL KS AND THROUGH SCNTL/ERN NEB EXITING AROUND 12Z.
THE QUESTION THOUGH IS HOW FAR WEST THE SECOND RAIN CENTER WILL
TRACK GIVEN THAT THE MODELS TREND WEST WITH RETURN MOISTURE. THE RAP
AND NAM PROVIDE AN ANSWER AS THEY ARE FARTHEST WEST AT 00Z WITH PWAT
NEAR 1.25 INCHES AND BACKED 850MB NEAR PAMPA TX. THIS MOISTURE
SHOULD MOVE NORTH-NORTHEAST DURING THE EVENING PRESENTING THE
POTENTIAL FOR HEAVY RAIN...0.5 TO 1 INCH EAST OF HIGHWAY 83 ACROSS
CUSTER COUNTY AND NORTHEAST. THE 1 INCH QPF IS SPECULATIVE. THE
MOISTURE IS VERY DEEP AND TRANSPORT EXTENDS TO 500 MB OR HIGHER AND
IS QUITE STRONG BELOW 700MB. WE WILL SEE WHAT HAPPENS TONIGHT. IF
SOME SORT OF LOW LEVEL BOUNDARY OR FOCUS DEVELOPS...NOT SHOWN BY
THE MODELS ATTM...THAN THE 1 INCH QPF COULD VERIFY SOMEWHERE. THE
QPF FORECAST FOLLOWS THE SREF AND NAM FOR UP TO 1/2 INCH OF RAIN IN
THE EAST AND UP TO 1/3 OF AN INCH WEST OF HIGHWAY 61.
THE "HURRICANE" CONTINUES TODAY. THE RAP13 500M AGL WINDS INCREASE
TO 25 TO 30 KTS WHICH IS 25 TO 30 MPH NEAR THE SFC WITH GUSTS TO 40
MPH IN OPEN AREAS.
THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARM SIDE OF THE MODEL
CLUSTER FOR HIGHS IN THE LOW TO MID 70S. THE RAP SHOWS 80 NEAR
VALENTINE AND 76 AT NORTH PLATTE. MID LEVEL CLOUDINESS SHOULD INVADE
THE REGION HOLDING HIGHS DOWN BELOW THE RAP FORECAST. LOWS TONIGHT
FALL INTO THE UPPER 40S TO MID 50S. THE NAM SHOWS OVERCAST SKIES AT
09Z WITH A CLEARING LINE NEAR HIGHWAY 61 AT 12Z EARLY THURSDAY
MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED MAY 13 2015
THE LARGE SCALE UPPER LEVEL PATTERN PERSISTS THROUGH THE END OF THE
WEEK AND INTO EARLY NEXT WEEK...DEFINED BY A DEEP TROUGH WITH
SEVERAL EMBEDDED PV ANOMALIES IN THE WESTERN CONUS AND BROAD
ANTICYCLONIC FLOW TO THE EAST. THIS PUTS THE CENTRAL CONUS IN A
FAVORABLE SYNOPTIC SETUP FOR POLEWARD MOISTURE TRANSPORT AND
RECURRING CHANCES FOR PRECIPITATION...INCLUDING THE POTENTIAL FOR
SEVERE WEATHER LATER THIS WEEK.
THURSDAY BEGINS WITH INHERITED MORNING POPS AS A SHORTWAVE DEPARTS
THE CENTRAL PLAINS AND MOVES INTO THE UPPER MS VALLEY. MODELS ARE IN
AGREEMENT WITH UPPER LEVEL HEIGHT RISES AND GRADUALLY CLEARING SKIES
BY THE AFTERNOON...SO TRENDED HIGH TEMPERATURES UP A FEW DEGREES TO
FOLLOW GUIDANCE. SFC WINDS WILL FINALLY EASE UP FOR A DAY DUE TO
WEAK PRESSURE TENANCIES OVER THE CWA...GENERALLY EXPECTING WINDS
AROUND 10 KTS.
POPS ARE QUICK TO MOVE BACK INTO THE FORECAST LATE THURSDAY AS THE
NEXT SHORTWAVE TROUGH ENTERS THE DESERT SOUTHWEST AND SWINGS OUT
TOWARD THE CENTRAL PLAINS. INCREASING DPVA ALOFT WILL PROMOTE A
DEEPENING LEE SIDE SFC TROUGH OVER EASTERN COLORADO AND THE SLOW
NORTHWARD PROGRESSION OF A WARM FRONT INTO NORTHERN KS. DEEP LAYER
MOISTURE PROFILE WILL BECOME INCREASINGLY FAVORABLE FOR
PRECIPITATION DUE TO EASTERLY UPSLOPE WINDS...AND A MID-LEVEL
SUBTROPICAL PLUME OFF THE BAJA TRANSPORTS BETTER MOISTURE ALOFT.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER DARK IN AN
AREA OF ISENTROPIC ASCENT NORTH OF THE WARM FRONT. THE CONVECTION
SHOULD FOLLOW THE WARM FRONT NORTHWARD INTO SOUTHERN SD EARLY
FRIDAY.
SEVERE WEATHER THREAT INCREASES FRIDAY AFTERNOON AND EVENING WITH
THE NEXT ROUND OF THUNDERSTORM ACTIVITY. SFC DEWPOINTS INCREASE TO
AROUND 60F INVOF A SHARPENING DRY LINE OVER WESTERN KS AND SOUTHWEST
NEBRASKA AND SOUTH OF THE WARM FRONT IN SOUTHERN SD. THE ATMOSPHERE
WILL BECOME QUITE UNSTABLE BY THE AFTERNOON AS MID LEVEL LAPSE RATES
STEEPEN AND SFC TEMPS WARM. THUNDERSTORMS SHOULD REFIRE ALONG THE
DRYLINE DURING THE AFTERNOON AND EVENING AS THE DRYLINE SURGES
NORTHEAST. STORMS WILL HAVE THE POTENTIAL TO BECOME SUPERCELLULAR IN
AN ENVIRONMENT CHARACTERIZED BY UP TO 2000 J/KG ML CAPE AND 40-45
KTS OF DEEP LAYER SHEAR. LARGE HAIL AND DAMAGING WIND WILL BE THE
PRIMARY THREATS...BUT LOW LEVEL SFC SHEAR PROFILES FAVOR ELONGATED
HODOGRAPHS AND THE POTENTIAL FOR A FEW TORNADOES.
THUNDERSTORMS AND THE THREAT FOR SEVERE WEATHER REDEVELOP SATURDAY
AS THE LARGE UPPER LEVEL LOW EJECTS TOWARD THE CENTRAL PLAINS. AT
THIS TIME THE AREA OF CONCERN IS GENERALLY EAST OF A SFC TROUGH
MOVING INTO CENTRAL AND EASTERN NEBRASKA. THE EARLY PART OF NEXT
WEEK LOOKS DRIER AS THE UPPER LOW KICKS NORTHEAST AND A RIDGE BUILDS
INTO THE CENTRAL CONUS. HOWEVER MODELS ARE QUICK TO BRING ANOTHER
TROUGH INTO THE ROCKIES BY TUESDAY...BRINGING WITH IT MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1250 PM CDT WED MAY 13 2015
MAIN AVIATION FCST CONCERNS REVOLVE AROUND SHRA/TSRA TIMING THIS
AFTERNOON AND EVENING. SFC TROUGH DEVELOPS IN THE PANHANDLE THIS
AFTERNOON IN RESPONSE TO UPPER PV ANOMALY MOVING NEWD IN THE NEXT
24 HRS. SOME INSTABILITY ALOFT IN CONCERT BUT CLOUD COVER WILL
LIMIT FURTHER DESTABILIZATION. HOWEVER...DECENT FGEN SIGNATURE
INDICATED IN IR SAT PICS AND LATEST 700MB RAP ANALYSIS IN NRN CO
SUGGESTS A DEEPER CIRCULATION SHOULD DEVELOP ALONG THE SFC TROUGH
LATER TO ENHANCE TSRA CHANCES THERE. FURTHER EWD...MAINLY SHRA IN
THE EVNING AND OVERNIGHT HOURS WITH LESSER INSTABILITY. DEPENDING
ON TIMING OF SHAR ENDING IN THE KLBF AND KVTN TAF SITES THERE
COULD BE BR DEVELOPMENT DURING THE EARLY MORNING HOURS. ONLY
MODERATE CONFIDENCE IN THIS HOWEVER AS WINDS SHIFT TO SWRLY DURING
MID MORNING. MORE CONFIDENCE IN THE KLBF TAF AND THEREFORE HAVE
INCLUDED FOR A LONGER PERIOD OF TIME. CLEARING SKIES TWD LATE
MORNING /END OF TAF PERIOD/ AS PRECIP MOVES OUT.
&&
.HYDROLOGY...
ISSUED AT 1250 PM CDT WED MAY 13 2015
FLOODING STILL EXPECTED ALONG THE SOUTH PLATTE AND PLATTE RIVER
FROM THE CO STATE LINE TO ERN LINCOLN COUNTY INTO THE WEEKEND DUE
TO SNOWMELT AND HEAVY RAINS IN NERN CO A FEW DAYS AGO /SEE DETAILS
IN FLOOD PRODUCTS AND STATEMENTS/. HOWEVER...TRENDS IN THE FCST...WITH
GOOD COLLAORATION FROM MBRFC...HAS BEEN A LOWERED FCST FOR THE
CREST IN NORTH PLATTE...THOUGH GETTING TO NEAR FLOOD STAGE BY THE
WEEKEND. FURTHER DETAILS IN LATER AFTERNOON AFD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...JWS
HYDROLOGY...JWS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
625 AM CDT WED MAY 13 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED MAY 13 2015
TODAY AND TONIGHT...THE SUBTROPICAL DISTURBANCE OFF OF BAJA MEXICO
YESTERDAY HAS MOVED NORTH INTO NEW MEXICO THIS MORNING. THE MODELS
LIFT THIS DISTURBANCE THROUGH THE CNTL PLAINS TODAY AND TONIGHT.
TWO CONVECTIVE ITEMS OF INTEREST HAVE BEEN IDENTIFIED AS THE
DISTURBANCE MOVES THRU WRN AND NCNTL NEBRASKA LATE THIS AFTN AND
TONIGHT. ONE IS A ROUND OF CONVECTION THAT SHOULD FIRE ON THE
COLORADO FRONT RANGE AND LARAMIE RANGE AROUND 18Z-21Z. THE STEERING
WINDS ALOFT CARRY THIS CONVECTION NNE THROUGH THE NEB PANHANDLE
AFFECTING AREAS MAINLY ALONG AND WEST OF HIGHWAY 61. MEANWHILE THE
SREF AND GEF SUGGEST A SECOND HEAVIER RAIN CENTER WILL MOVE ACROSS
WCNTL KS AND THROUGH SCNTL/ERN NEB EXITING AROUND 12Z.
THE QUESTION THOUGH IS HOW FAR WEST THE SECOND RAIN CENTER WILL
TRACK GIVEN THAT THE MODELS TREND WEST WITH RETURN MOISTURE. THE RAP
AND NAM PROVIDE AN ANSWER AS THEY ARE FARTHEST WEST AT 00Z WITH PWAT
NEAR 1.25 INCHES AND BACKED 850MB NEAR PAMPA TX. THIS MOISTURE
SHOULD MOVE NORTH-NORTHEAST DURING THE EVENING PRESENTING THE
POTENTIAL FOR HEAVY RAIN...0.5 TO 1 INCH EAST OF HIGHWAY 83 ACROSS
CUSTER COUNTY AND NORTHEAST. THE 1 INCH QPF IS SPECULATIVE. THE
MOISTURE IS VERY DEEP AND TRANSPORT EXTENDS TO 500 MB OR HIGHER AND
IS QUITE STRONG BELOW 700MB. WE WILL SEE WHAT HAPPENS TONIGHT. IF
SOME SORT OF LOW LEVEL BOUNDARY OR FOCUS DEVELOPS...NOT SHOWN BY
THE MODELS ATTM...THAN THE 1 INCH QPF COULD VERIFY SOMEWHERE. THE
QPF FORECAST FOLLOWS THE SREF AND NAM FOR UP TO 1/2 INCH OF RAIN IN
THE EAST AND UP TO 1/3 OF AN INCH WEST OF HIGHWAY 61.
THE "HURRICANE" CONTINUES TODAY. THE RAP13 500M AGL WINDS INCREASE
TO 25 TO 30 KTS WHICH IS 25 TO 30 MPH NEAR THE SFC WITH GUSTS TO 40
MPH IN OPEN AREAS.
THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARM SIDE OF THE MODEL
CLUSTER FOR HIGHS IN THE LOW TO MID 70S. THE RAP SHOWS 80 NEAR
VALENTINE AND 76 AT NORTH PLATTE. MID LEVEL CLOUDINESS SHOULD INVADE
THE REGION HOLDING HIGHS DOWN BELOW THE RAP FORECAST. LOWS TONIGHT
FALL INTO THE UPPER 40S TO MID 50S. THE NAM SHOWS OVERCAST SKIES AT
09Z WITH A CLEARING LINE NEAR HIGHWAY 61 AT 12Z EARLY THURSDAY
MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED MAY 13 2015
THE LARGE SCALE UPPER LEVEL PATTERN PERSISTS THROUGH THE END OF THE
WEEK AND INTO EARLY NEXT WEEK...DEFINED BY A DEEP TROUGH WITH
SEVERAL EMBEDDED PV ANOMALIES IN THE WESTERN CONUS AND BROAD
ANTICYCLONIC FLOW TO THE EAST. THIS PUTS THE CENTRAL CONUS IN A
FAVORABLE SYNOPTIC SETUP FOR POLEWARD MOISTURE TRANSPORT AND
RECURRING CHANCES FOR PRECIPITATION...INCLUDING THE POTENTIAL FOR
SEVERE WEATHER LATER THIS WEEK.
THURSDAY BEGINS WITH INHERITED MORNING POPS AS A SHORTWAVE DEPARTS
THE CENTRAL PLAINS AND MOVES INTO THE UPPER MS VALLEY. MODELS ARE IN
AGREEMENT WITH UPPER LEVEL HEIGHT RISES AND GRADUALLY CLEARING SKIES
BY THE AFTERNOON...SO TRENDED HIGH TEMPERATURES UP A FEW DEGREES TO
FOLLOW GUIDANCE. SFC WINDS WILL FINALLY EASE UP FOR A DAY DUE TO
WEAK PRESSURE TENANCIES OVER THE CWA...GENERALLY EXPECTING WINDS
AROUND 10 KTS.
POPS ARE QUICK TO MOVE BACK INTO THE FORECAST LATE THURSDAY AS THE
NEXT SHORTWAVE TROUGH ENTERS THE DESERT SOUTHWEST AND SWINGS OUT
TOWARD THE CENTRAL PLAINS. INCREASING DPVA ALOFT WILL PROMOTE A
DEEPENING LEE SIDE SFC TROUGH OVER EASTERN COLORADO AND THE SLOW
NORTHWARD PROGRESSION OF A WARM FRONT INTO NORTHERN KS. DEEP LAYER
MOISTURE PROFILE WILL BECOME INCREASINGLY FAVORABLE FOR
PRECIPITATION DUE TO EASTERLY UPSLOPE WINDS...AND A MID-LEVEL
SUBTROPICAL PLUME OFF THE BAJA TRANSPORTS BETTER MOISTURE ALOFT.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER DARK IN AN
AREA OF ISENTROPIC ASCENT NORTH OF THE WARM FRONT. THE CONVECTION
SHOULD FOLLOW THE WARM FRONT NORTHWARD INTO SOUTHERN SD EARLY
FRIDAY.
SEVERE WEATHER THREAT INCREASES FRIDAY AFTERNOON AND EVENING WITH
THE NEXT ROUND OF THUNDERSTORM ACTIVITY. SFC DEWPOINTS INCREASE TO
AROUND 60F INVOF A SHARPENING DRY LINE OVER WESTERN KS AND SOUTHWEST
NEBRASKA AND SOUTH OF THE WARM FRONT IN SOUTHERN SD. THE ATMOSPHERE
WILL BECOME QUITE UNSTABLE BY THE AFTERNOON AS MID LEVEL LAPSE RATES
STEEPEN AND SFC TEMPS WARM. THUNDERSTORMS SHOULD REFIRE ALONG THE
DRYLINE DURING THE AFTERNOON AND EVENING AS THE DRYLINE SURGES
NORTHEAST. STORMS WILL HAVE THE POTENTIAL TO BECOME SUPERCELLULAR IN
AN ENVIRONMENT CHARACTERIZED BY UP TO 2000 J/KG ML CAPE AND 40-45
KTS OF DEEP LAYER SHEAR. LARGE HAIL AND DAMAGING WIND WILL BE THE
PRIMARY THREATS...BUT LOW LEVEL SFC SHEAR PROFILES FAVOR ELONGATED
HODOGRAPHS AND THE POTENTIAL FOR A FEW TORNADOES.
THUNDERSTORMS AND THE THREAT FOR SEVERE WEATHER REDEVELOP SATURDAY
AS THE LARGE UPPER LEVEL LOW EJECTS TOWARD THE CENTRAL PLAINS. AT
THIS TIME THE AREA OF CONCERN IS GENERALLY EAST OF A SFC TROUGH
MOVING INTO CENTRAL AND EASTERN NEBRASKA. THE EARLY PART OF NEXT
WEEK LOOKS DRIER AS THE UPPER LOW KICKS NORTHEAST AND A RIDGE BUILDS
INTO THE CENTRAL CONUS. HOWEVER MODELS ARE QUICK TO BRING ANOTHER
TROUGH INTO THE ROCKIES BY TUESDAY...BRINGING WITH IT MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 625 AM CDT WED MAY 13 2015
VFR IS EXPECTED THROUGH 21Z THIS AFTN. THEREAFTER...THE UPPER
LEVEL DISTURBANCE ACROSS NEW MEXICO WILL SPREAD RAIN...SHRA AND
ISOLD TSTMS INTO THE FCST AREA FROM SOUTH TO NORTH. MVFR/IFR IS
EXPECTED IN RAIN AND LOW CIGS THIS EVENING. THE SREF INDICATES A
HIGH PROBABILITY OF IFR CIGS ALONG AND EAST OF HIGHWAY 61 FROM
06Z-12Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
323 AM CDT WED MAY 13 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT WED MAY 13 2015
TODAY AND TONIGHT...THE SUBTROPICAL DISTURBANCE OFF OF BAJA MEXICO
YESTERDAY HAS MOVED NORTH INTO NEW MEXICO THIS MORNING. THE MODELS
LIFT THIS DISTURBANCE THROUGH THE CNTL PLAINS TODAY AND TONIGHT.
TWO CONVECTIVE ITEMS OF INTEREST HAVE BEEN IDENTIFIED AS THE
DISTURBANCE MOVES THRU WRN AND NCNTL NEBRASKA LATE THIS AFTN AND
TONIGHT. ONE IS A ROUND OF CONVECTION THAT SHOULD FIRE ON THE
COLORADO FRONT RANGE AND LARAMIE RANGE AROUND 18Z-21Z. THE STEERING
WINDS ALOFT CARRY THIS CONVECTION NNE THROUGH THE NEB PANHANDLE
AFFECTING AREAS MAINLY ALONG AND WEST OF HIGHWAY 61. MEANWHILE THE
SREF AND GEF SUGGEST A SECOND HEAVIER RAIN CENTER WILL MOVE ACROSS
WCNTL KS AND THROUGH SCNTL/ERN NEB EXITING AROUND 12Z.
THE QUESTION THOUGH IS HOW FAR WEST THE SECOND RAIN CENTER WILL
TRACK GIVEN THAT THE MODELS TREND WEST WITH RETURN MOISTURE. THE RAP
AND NAM PROVIDE AN ANSWER AS THEY ARE FARTHEST WEST AT 00Z WITH PWAT
NEAR 1.25 INCHES AND BACKED 850MB NEAR PAMPA TX. THIS MOISTURE
SHOULD MOVE NORTH-NORTHEAST DURING THE EVENING PRESENTING THE
POTENTIAL FOR HEAVY RAIN...0.5 TO 1 INCH EAST OF HIGHWAY 83 ACROSS
CUSTER COUNTY AND NORTHEAST. THE 1 INCH QPF IS SPECULATIVE. THE
MOISTURE IS VERY DEEP AND TRANSPORT EXTENDS TO 500 MB OR HIGHER AND
IS QUITE STRONG BELOW 700MB. WE WILL SEE WHAT HAPPENS TONIGHT. IF
SOME SORT OF LOW LEVEL BOUNDARY OR FOCUS DEVELOPS...NOT SHOWN BY
THE MODELS ATTM...THAN THE 1 INCH QPF COULD VERIFY SOMEWHERE. THE
QPF FORECAST FOLLOWS THE SREF AND NAM FOR UP TO 1/2 INCH OF RAIN IN
THE EAST AND UP TO 1/3 OF AN INCH WEST OF HIGHWAY 61.
THE "HURRICANE" CONTINUES TODAY. THE RAP13 500M AGL WINDS INCREASE
TO 25 TO 30 KTS WHICH IS 25 TO 30 MPH NEAR THE SFC WITH GUSTS TO 40
MPH IN OPEN AREAS.
THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARM SIDE OF THE MODEL
CLUSTER FOR HIGHS IN THE LOW TO MID 70S. THE RAP SHOWS 80 NEAR
VALENTINE AND 76 AT NORTH PLATTE. MID LEVEL CLOUDINESS SHOULD INVADE
THE REGION HOLDING HIGHS DOWN BELOW THE RAP FORECAST. LOWS TONIGHT
FALL INTO THE UPPER 40S TO MID 50S. THE NAM SHOWS OVERCAST SKIES AT
09Z WITH A CLEARING LINE NEAR HIGHWAY 61 AT 12Z EARLY THURSDAY
MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CDT WED MAY 13 2015
THE LARGE SCALE UPPER LEVEL PATTERN PERSISTS THROUGH THE END OF THE
WEEK AND INTO EARLY NEXT WEEK...DEFINED BY A DEEP TROUGH WITH
SEVERAL EMBEDDED PV ANOMALIES IN THE WESTERN CONUS AND BROAD
ANTICYCLONIC FLOW TO THE EAST. THIS PUTS THE CENTRAL CONUS IN A
FAVORABLE SYNOPTIC SETUP FOR POLEWARD MOISTURE TRANSPORT AND
RECURRING CHANCES FOR PRECIPITATION...INCLUDING THE POTENTIAL FOR
SEVERE WEATHER LATER THIS WEEK.
THURSDAY BEGINS WITH INHERITED MORNING POPS AS A SHORTWAVE DEPARTS
THE CENTRAL PLAINS AND MOVES INTO THE UPPER MS VALLEY. MODELS ARE IN
AGREEMENT WITH UPPER LEVEL HEIGHT RISES AND GRADUALLY CLEARING SKIES
BY THE AFTERNOON...SO TRENDED HIGH TEMPERATURES UP A FEW DEGREES TO
FOLLOW GUIDANCE. SFC WINDS WILL FINALLY EASE UP FOR A DAY DUE TO
WEAK PRESSURE TENANCIES OVER THE CWA...GENERALLY EXPECTING WINDS
AROUND 10 KTS.
POPS ARE QUICK TO MOVE BACK INTO THE FORECAST LATE THURSDAY AS THE
NEXT SHORTWAVE TROUGH ENTERS THE DESERT SOUTHWEST AND SWINGS OUT
TOWARD THE CENTRAL PLAINS. INCREASING DPVA ALOFT WILL PROMOTE A
DEEPENING LEE SIDE SFC TROUGH OVER EASTERN COLORADO AND THE SLOW
NORTHWARD PROGRESSION OF A WARM FRONT INTO NORTHERN KS. DEEP LAYER
MOISTURE PROFILE WILL BECOME INCREASINGLY FAVORABLE FOR
PRECIPITATION DUE TO EASTERLY UPSLOPE WINDS...AND A MID-LEVEL
SUBTROPICAL PLUME OFF THE BAJA TRANSPORTS BETTER MOISTURE ALOFT.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AFTER DARK IN AN
AREA OF ISENTROPIC ASCENT NORTH OF THE WARM FRONT. THE CONVECTION
SHOULD FOLLOW THE WARM FRONT NORTHWARD INTO SOUTHERN SD EARLY
FRIDAY.
SEVERE WEATHER THREAT INCREASES FRIDAY AFTERNOON AND EVENING WITH
THE NEXT ROUND OF THUNDERSTORM ACTIVITY. SFC DEWPOINTS INCREASE TO
AROUND 60F INVOF A SHARPENING DRY LINE OVER WESTERN KS AND SOUTHWEST
NEBRASKA AND SOUTH OF THE WARM FRONT IN SOUTHERN SD. THE ATMOSPHERE
WILL BECOME QUITE UNSTABLE BY THE AFTERNOON AS MID LEVEL LAPSE RATES
STEEPEN AND SFC TEMPS WARM. THUNDERSTORMS SHOULD REFIRE ALONG THE
DRYLINE DURING THE AFTERNOON AND EVENING AS THE DRYLINE SURGES
NORTHEAST. STORMS WILL HAVE THE POTENTIAL TO BECOME SUPERCELLULAR IN
AN ENVIRONMENT CHARACTERIZED BY UP TO 2000 J/KG ML CAPE AND 40-45
KTS OF DEEP LAYER SHEAR. LARGE HAIL AND DAMAGING WIND WILL BE THE
PRIMARY THREATS...BUT LOW LEVEL SFC SHEAR PROFILES FAVOR ELONGATED
HODOGRAPHS AND THE POTENTIAL FOR A FEW TORNADOES.
THUNDERSTORMS AND THE THREAT FOR SEVERE WEATHER REDEVELOP SATURDAY
AS THE LARGE UPPER LEVEL LOW EJECTS TOWARD THE CENTRAL PLAINS. AT
THIS TIME THE AREA OF CONCERN IS GENERALLY EAST OF A SFC TROUGH
MOVING INTO CENTRAL AND EASTERN NEBRASKA. THE EARLY PART OF NEXT
WEEK LOOKS DRIER AS THE UPPER LOW KICKS NORTHEAST AND A RIDGE BUILDS
INTO THE CENTRAL CONUS. HOWEVER MODELS ARE QUICK TO BRING ANOTHER
TROUGH INTO THE ROCKIES BY TUESDAY...BRINGING WITH IT MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1129 PM CDT TUE MAY 12 2015
UNLIMITED CEILING AND VISIBILITY CAN BE EXPECTED THROUGH MOST OF THE
DAY WEDNESDAY. THUNDERSTORMS ARE EXPECTED TO BEGIN DEVELOPING IN
EXTREME WESTERN NEBRASKA EARLY AFTERNOON AND ARE LIKELY TO SPREAD
INTO THE REST OF WESTERN NEBRASKA LATE AFTERNOON THROUGH EARLY
EVENING. BY EARLY EVENING...THE COVERAGE OF THE STORMS WILL BE 50
PERCENT OR HIGHER AND WE WILL INCLUDE THEM IN THE FORECASTS FOR LBF
AND VTN. STORMS WILL THEN MAKE THEIR WAY INTO CENTRAL NEBRASKA TO
AFFECT ONL...BBW...ANW.
WIND TONIGHT WILL CONTINUE 130-170 AT 12-16KT AND...BY 16Z INCREASE
AND BECOME 160-200 AT 16-20G25-30KT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...SPRINGER
LOCATIONS. THE PREVIOUS FORECAST DISCUSSION FOLLOWS.
KLTX VAD WIND PROFILE REGISTERING 3000 FOOT THICK NORTH FLOW
ACROSS THE REGION PRESENTLY IN WAKE OF A COLD FRONT WHICH HAS
MIGRATED SOUTH AND EAST OF THE AREA. A BAND OF MIDDLE AND HIGH
CLOUDS FROM 12 KFT UPWARD ARE TRAVERSING OUR SKIES AND WILL DO SO
THROUGH MORNING WITH AN UPTICK IN SUNSHINE MINUTES ANTICIPATED
THIS AFTERNOON. COOLING BEHIND THE FRONT WILL OCCUR MAINLY TONIGHT
AS THE GREAT LAKES HIGH BEGINS TO FALL TOWARD THE MID-ATLANTIC.
DESCENDING DEWPOINTS ON TAP WILL EVACUATE ANY VESTIGES OF
MUGGINESS LOITERING ACROSS THE CAROLINAS. COMFORTABLY WARM
MAXIMUMS TODAY SHOULD RISE TO 80-84 MOST INLAND LOCALITIES TO
76-79 ALONG THE COAST. THE BRUNSWICK COAST MAY GO WARMER IN THE
NEAR DIRECT OFFSHORE WIND REGIME.
THIS EVENING WINDOW-OPEN TYPE CONDITIONS AS TEMPERATURES COOL TO
70 AND BELOW AFTER THE SUN HAS SUNK BELOW THE HORIZON. COOLING
WILL BRING MINIMUMS INTO DAYBREAK THURSDAY INTO THE MIDDLE 50S
WELL INLAND TO THE UPPER 50S COASTAL INTERIOR TO THE LOW 60S
COASTAL ZONES AMID A NE WIND FLOW.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SETTLE DOWN OVER THE
CAROLINAS FROM THE NORTH AS MID TO UPPER RIDGE ALIGNS ITSELF UP
THE EAST COAST THURS INTO FRI. OVERALL EXPECT A RAIN FREE PERIOD
WITH PLENTY OF DRY AIR AND SUBSIDENCE THROUGH THE MID LEVELS OF
THE ATMOSPHERE. MAY SEE SOME FLAT CU DEVELOPING WITH HEATING OF
THE DAY AIDED BY SOME CONVERGENCE ALONG SEA BREEZE BUT STRONG
SUBSIDENCE INVERSION WILL NOT ALLOW MUCH DEPTH TO ANY CU. ALTHOUGH
SUNSHINE SHOULD BE QUITE PLENTIFUL THROUGH THE PERIOD...SOME
HIGHER LEVEL CLOUDS WILL SPREAD INTO THE CAROLINAS OVER THE RIDGE
AS IT SLIPS EAST...ESPECIALLY TOWARD THE END OF THE FRIDAY. THE
CENTER OF THE SFC HIGH WILL SHIFT FURTHER EAST ALSO...OFF THE MID
ATLANTIC COAST BY LATE FRI. THEREFORE DRIER NORTHERLY FLOW WILL
SHIFT TO A GREATER ON SHORE TO S-SE MOISTER RETURN FLOW THROUGH
FRI NIGHT INTO THE WEEKEND AND AIR MASS WILL BEGIN TO MODIFY.
AN OVERALL DRY AIR MASS IN PLACE WILL PRODUCE GREAT DIURNAL
SWINGS WITH LOWER DEWPOINTS DOWN CLOSE TO 50 ALLOWING OVERNIGHT
TEMPS TO DROP OFF QUICKLY DOWN TO THE 50S UNDER MAINLY CLEAR SKIES
AND LIGHT TO CALM WINDS. AFTER A RELATIVELY COOLER START TO THE
DAYS...TEMPS WILL RECOVER TO NEAR SEASONABLE VALUES UNDER MAY
SUNSHINE...INTO THE UPPER 70S MOST PLACES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM WEDNESDAY...MID TO UPPER RIDGE WILL SHIFT A LITTLE
BUT OVERALL WILL CONTINUE TO HOLD ON UP THROUGH THE
SOUTHEAST...PRODUCING SUBSIDENCE OVER THE AREA. THE SFC HIGH WILL
CONTINUE TO SLIP FARTHER EAST WHICH WILL PRODUCE A GREATER
SOUTHERLY RETURN FLOW OF MOISTURE WITH DEWPOINT TEMPS REACHING
BACK UP INTO AND THROUGH THE 60S DURING THE WEEKEND INTO EARLY
NEXT WEEK. SOME MID TO HIGH CLOUDS WILL CONTINUE TO RIDE THE COLD
FRONT RUNS FROM NEAR JACKSONVILLE NC TO NEAR WHITEVILLE TO SOUTH
OF FLORENCE SC. THIS IS STILL SLOWER THAN ANY MODEL SHOWED JUST
FIVE HOURS AGO...BUT IT APPEARS THE LATEST HRRR MODEL HAS A
REASONABLE HANDLE ON THE MOVEMENT OF THIS FEATURE OVER THE NEXT
FEW HOURS. THE 00Z GFS APPEARS TO HAVE HAD PROBLEMS THIS MORNING
WITH A TOO-RAPID FRONTAL PASSAGE AND ODD WIND DIRECTIONS
THROUGHOUT THE DAY COMPARED TO THE REST OF THE MODELS. FOR WINDS
AND TEMPERATURES I HAVE STAYED CLOSER THE 00Z NAM AS A RESULT.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VFR EXPECTED THROUGH THIS TAF VALID PERIOD. SATELLITE
IMAGES SHOW UPPER CLOUDS HAVE SCATTERED AT KFLO/KLBT AND WILL
SCATTER AT THE COASTAL TERMINALS IN THE NEXT HOUR OR SO. WINDS WILL
BE N-NE THIS AFTERNOON BECOMING E AT THE COASTAL TERMINALS MID TO
LATE AFTERNOON.
WINDS BECOME NE FOR THE OVERNIGHT PERIOD. NO FOG EXPECTED. SCT LOW
CLOUDS AROUND 4K POSSIBLE OVERNIGHT INTO THURSDAY MORNING. WINDS
CONTINUE NE THURSDAY MORNING AS A SOMEWHAT BRISKER PACE THAN TODAY.
EXTENDED OUTLOOK...VFR. ISOLATED SHOWERS SAT BECOMING SCATTERED
SUN. BETTER CHANCES FOR SHOWERS/THUNDERSTORMS MON/TUE.&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM WEDNESDAY...MODERATE NE WINDS SKIPPING ACROSS THE
WATERS BUT NO ADVISORIES OR EXERCISE CAUTION STATEMENTS ARE
PLANNED. WINDS WILL VEER CLOSER TO E MID AND LATE AFTERNOON WITH
ASSISTANCE FROM SEA BREEZE DYNAMICS. SEAS 2 TO 4 FEET OVERALL
WITH DOMINANT PERIODS AROUND 6 SECONDS. NO TSTMS OR RESTRICTIONS
TO VISIBILITY EXPECTED THROUGH TONIGHT. WINDS ENE TONIGHT 10-15
KT...THEN GUSTS TO 20 NEAR DAYBREAK AS HIGH PRESSURE FROM THE
GREAT LAKES BUILDS SE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE BUILDING DOWN FROM THE
NORTH WILL SHIFT EAST THROUGH THE PERIOD EVENTUALLY SHIFTING OFF
THE MID ATLANTIC COAST ON FRI. NORTHEASTERLY FLOW UP TO 15 KTS ON
THE FRONT END WILL LIGHTEN AND VEER AROUND BECOMING MORE NORTHEAST
TO EAST THROUGH THURS AND THEN E-SE FRI NIGHT INTO THE WEEKEND.
SEAS WILL BASICALLY REMAIN IN THE 2 TO 4 FT RANGE.
.LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SHIFT OFFSHORE EARLY
IN THE WEEKEND PRODUCING A SOUTHEASTERLY ON SHORE FLOW LESS THAN
15 KTS. A SEA BREEZE WILL DEVELOP EACH AFTERNOON ADDING TO THE SE
PUSH AND PRODUCING GUSTY ON SHORE WINDS AND SOME CHOP IN THE NEAR
SHORE WATERS EACH AFTERNOON. OVERALL EXPECT SEAS IN THE 2 TO 4 FT
RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
953 AM EDT WED MAY 13 2015
.SYNOPSIS...
DRIER AIR WILL SPREAD INTO THE REGION TODAY AND THURSDAY WITH
SLIGHT COOLING TONIGHT. HIGH PRESSURE FROM THE GREAT LAKES WILL
MOVE OFFSHORE BEGINNING FRIDAY...BRINGING A GRADUAL INCREASE IN
HUMIDITY AND THUNDERSTORM DEVELOPMENT THROUGH THE WEEKEND INTO
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 952 AM WEDNESDAY...KLTX VAD WIND PROFILE REGISTERING 3000
FOOT THICK NORTH FLOW ACROSS THE REGION PRESENTLY IN WAKE OF A
COLD FRONT WHICH HAS MIGRATED SOUTH AND EAST OF THE AREA. A BAND
OF MIDDLE AND HIGH CLOUDS FROM 12 KFT UPWARD ARE TRAVERSING OUR
SKIES AND WILL DO SO THROUGH MORNING WITH AN UPTICK IN SUNSHINE
MINUTES ANTICIPATED THIS AFTERNOON. COOLING BEHIND THE FRONT WILL
OCCUR MAINLY TONIGHT AS THE GREAT LAKES HIGH BEGINS TO FALL TOWARD
THE MID-ATLANTIC. DESCENDING DEWPOINTS ON TAP WILL EVACUATE ANY
VESTIGES OF MUGGINESS LOITERING ACROSS THE CAROLINAS. COMFORTABLY
WARM MAXIMUMS TODAY SHOULD RISE TO 80-84 MOST INLAND LOCALITIES TO
76-79 ALONG THE COAST. THE BRUNSWICK COAST MAY GO WARMER IN THE
NEAR DIRECT OFFSHORE WIND REGIME.
THIS EVENING WINDOW-OPEN TYPE CONDITIONS AS TEMPERATURES COOL TO
70 AND BELOW AFTER THE SUN HAS SUNK BELOW THE HORIZON. COOLING
WILL BRING MINIMUMS INTO DAYBREAK THURSDAY INTO THE MIDDLE 50S
WELL INLAND TO THE UPPER 50S COASTAL INTERIOR TO THE LOW 60S
COASTAL ZONES AMID A NE WIND FLOW.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SETTLE DOWN OVER THE
CAROLINAS FROM THE NORTH AS MID TO UPPER RIDGE ALIGNS ITSELF UP
THE EAST COAST THURS INTO FRI. OVERALL EXPECT A RAIN FREE PERIOD
WITH PLENTY OF DRY AIR AND SUBSIDENCE THROUGH THE MID LEVELS OF
THE ATMOSPHERE. MAY SEE SOME FLAT CU DEVELOPING WITH HEATING OF
THE DAY AIDED BY SOME CONVERGENCE ALONG SEA BREEZE BUT STRONG
SUBSIDENCE INVERSION WILL NOT ALLOW MUCH DEPTH TO ANY CU. ALTHOUGH
SUNSHINE SHOULD BE QUITE PLENTIFUL THROUGH THE PERIOD...SOME
HIGHER LEVEL CLOUDS WILL SPREAD INTO THE CAROLINAS OVER THE RIDGE
AS IT SLIPS EAST...ESPECIALLY TOWARD THE END OF THE FRIDAY. THE
CENTER OF THE SFC HIGH WILL SHIFT FURTHER EAST ALSO...OFF THE MID
ATLANTIC COAST BY LATE FRI. THEREFORE DRIER NORTHERLY FLOW WILL
SHIFT TO A GREATER ON SHORE TO S-SE MOISTER RETURN FLOW THROUGH
FRI NIGHT INTO THE WEEKEND AND AIR MASS WILL BEGIN TO MODIFY.
AN OVERALL DRY AIR MASS IN PLACE WILL PRODUCE GREAT DIURNAL
SWINGS WITH LOWER DEWPOINTS DOWN CLOSE TO 50 ALLOWING OVERNIGHT
TEMPS TO DROP OFF QUICKLY DOWN TO THE 50S UNDER MAINLY CLEAR SKIES
AND LIGHT TO CALM WINDS. AFTER A RELATIVELY COOLER START TO THE
DAYS...TEMPS WILL RECOVER TO NEAR SEASONABLE VALUES UNDER MAY
SUNSHINE...INTO THE UPPER 70S MOST PLACES.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID TO UPPER RIDGE WILL SHIFT A LITTLE
BUT OVERALL WILL CONTINUE TO HOLD ON UP THROUGH THE
SOUTHEAST...PRODUCING SUBSIDENCE OVER THE AREA. THE SFC HIGH WILL
CONTINUE TO SLIP FARTHER EAST WHICH WILL PRODUCE A GREATER
SOUTHERLY RETURN FLOW OF MOISTURE WITH DEWPOINT TEMPS REACHING
BACK UP INTO AND THROUGH THE 60S DURING THE WEEKEND INTO EARLY
NEXT WEEK. SOME MID TO HIGH CLOUDS WILL CONTINUE TO RIDE THE COLD
FRONT RUNS FROM NEAR JACKSONVILLE NC TO NEAR WHITEVILLE TO SOUTH
OF FLORENCE SC. THIS IS STILL SLOWER THAN ANY MODEL SHOWED JUST
FIVE HOURS AGO...BUT IT APPEARS THE LATEST HRRR MODEL HAS A
REASONABLE HANDLE ON THE MOVEMENT OF THIS FEATURE OVER THE NEXT
FEW HOURS. THE 00Z GFS APPEARS TO HAVE HAD PROBLEMS THIS MORNING
WITH A TOO-RAPID FRONTAL PASSAGE AND ODD WIND DIRECTIONS
THROUGHOUT THE DAY COMPARED TO THE REST OF THE MODELS. FOR WINDS
AND TEMPERATURES I HAVE STAYED CLOSER THE 00Z NAM AS A RESULT.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...VFR EXPECTED THROUGH THIS TAF VALID PERIOD. KLTX
VAD WIND PROFILE INDICATES N WINDS JUST OFF THE SURFACE SO THE
COLD FRONT SOUTH OF KMYR WITHIN HE NEXT HOUR OR TWO. IT ALSO
INDICATES A SMATTERING MID CLOUD LAYERS WITH A MORE PERSISTENT
CLOUD DECK 18K-20K.
WINDS WILL BE N-NE THIS MORNING BECOMING E AT THE COASTAL
TERMINALS IN THE AFTERNOON. MID/UPPER CLOUDS WILL MOVE OFF IN THE
AFTERNOON AS A FEW/SCT LOW LEVEL CU DEVELOPS. UPPER CLOUDS RETURN
IN THE LATE EVENING AS WINDS BECOME NE FOR THE OVERNIGHT PERIOD.
NO FOG EXPECTED.
EXTENDED OUTLOOK...VFR. ISOLATED SHOWERS FRIDAY...BECOMING SCATTERED
SAT AND SUN. BETTER CHANCES FOR CONVECTION MON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 952 AM WEDNESDAY...MODERATE N WINDS SKIPPING ACROSS THE
WATERS BUT NO ADVISORIES OR EXERCISE CAUTION STATEMENTS ARE
PLANNED. GUSTS TO 20 KT CANNOT BE RULED OUT BRIEFLY THIS MORNING
IN THIS INITIAL SURGE...AND AGAIN IN THE PRE-DAWN THURSDAY AS
GREAT LAKES HIGH PRESSURE MOVES TOWARD OUR COAST. SEAS 2 TO 4 FEET
OVERALL WITH DOMINANT PERIODS AROUND 6 SECONDS. NO TSTMS OR
RESTRICTIONS TO VISIBILITY EXPECTED THROUGH TONIGHT. WINDS WILL
TEND TO NE TONIGHT 10-15 KT...THEN GUSTS TO 20 NEAR DAYBREAK.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE BUILDING DOWN FROM THE
NORTH WILL SHIFT EAST THROUGH THE PERIOD EVENTUALLY SHIFTING OFF
THE MID ATLANTIC COAST ON FRI. NORTHEASTERLY FLOW UP TO 15 KTS ON
THE FRONT END WILL LIGHTEN AND VEER AROUND BECOMING MORE NORTHEAST
TO EAST THROUGH THURS AND THEN E-SE FRI NIGHT INTO THE WEEKEND.
SEAS WILL BASICALLY REMAIN IN THE 2 TO 4 FT RANGE.
.LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SHIFT OFFSHORE EARLY
IN THE WEEKEND PRODUCING A SOUTHEASTERLY ON SHORE FLOW LESS THAN
15 KTS. A SEA BREEZE WILL DEVELOP EACH AFTERNOON ADDING TO THE SE
PUSH AND PRODUCING GUSTY ON SHORE WINDS AND SOME CHOP IN THE NEAR
SHORE WATERS EACH AFTERNOON. OVERALL EXPECT SEAS IN THE 2 TO 4 FT
RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
754 AM EDT WED MAY 13 2015
.SYNOPSIS...
LESS HUMID AIR WILL ARRIVE TODAY AND SHOULD LAST INTO EARLY FRIDAY AS
HIGH PRESSURE BUILDS DOWN FROM THE NORTH. THE LATTER PART OF THE
WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND
THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...THE COLD FRONT RUNS FROM NEAR JACKSONVILLE
NC TO NEAR WHITEVILLE TO SOUTH OF FLORENCE SC. THIS IS STILL SLOWER
THAN ANY MODEL SHOWED JUST FIVE HOURS AGO...BUT IT APPEARS THE
LATEST HRRR MODEL HAS A REASONABLE HANDLE ON THE MOVEMENT OF THIS
FEATURE OVER THE NEXT FEW HOURS. THE 00Z GFS APPEARS TO HAVE HAD
PROBLEMS THIS MORNING WITH A TOO-RAPID FRONTAL PASSAGE AND ODD WIND
DIRECTIONS THROUGHOUT THE DAY COMPARED TO THE REST OF THE MODELS.
FOR WINDS AND TEMPERATURES I HAVE STAYED CLOSER THE 00Z NAM AS A
RESULT.
SHOWER CHANCES ARE QUITE LOW THROUGH THE MORNING. FORECAST SOUNDINGS
SHOW A SMALL REGION OF CONDITIONAL INSTABILITY BASED ABOVE THE
SURFACE WHICH COULD GENERATE AN ISOLATED SHOWER UP THROUGH THE TIME
OF FRONTAL PASSAGE. HOWEVER GIVEN POOR FORCING AND INCREASING
LIMITED VERTICAL MOISTURE...ODDS OF DEVELOPING SHOWERS ARE LESS THAN
10 PERCENT...AND WILL NOT BE MENTIONED IN THE FORECAST.
CONSIDERABLE CIRRUS CLOUDINESS WILL HANG AROUND THROUGH THE MORNING.
GLANCING OUT IN THE NWS OFFICE PARKING LOT THE CLOUDS ARE FAIRLY
OPAQUE BUT HAVE ENOUGH BREAKS AND THIN SPOTS TO LET ENOUGH SUN
THROUGH TO BOOST TEMPERATURES INTO THE UPPER 70S BY NOON. NEARLY
FULL SUNSHINE SHOULD DEVELOP THIS AFTERNOON AS THE CIRRUS ADVECTS
OFFSHORE...AND HIGHS SHOULD REACH 79-84 AWAY FROM THE BEACHES.
LINEAR MOTION EXTRAPOLATION ON THE BACK EDGE OF THE CLOUDS BRINGS IT
TO FLORENCE AROUND NOON...AND WILMINGTON AROUND 2 PM.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SETTLE DOWN OVER THE
CAROLINAS FROM THE NORTH AS MID TO UPPER RIDGE ALIGNS ITSELF UP
THE EAST COAST THURS INTO FRI. OVERALL EXPECT A RAIN FREE PERIOD
WITH PLENTY OF DRY AIR AND SUBSIDENCE THROUGH THE MID LEVELS OF
THE ATMOSPHERE. MAY SEE SOME FLAT CU DEVELOPING WITH HEATING OF
THE DAY AIDED BY SOME CONVERGENCE ALONG SEA BREEZE BUT STRONG
SUBSIDENCE INVERSION WILL NOT ALLOW MUCH DEPTH TO ANY CU. ALTHOUGH
SUNSHINE SHOULD BE QUITE PLENTIFUL THROUGH THE PERIOD...SOME
HIGHER LEVEL CLOUDS WILL SPREAD INTO THE CAROLINAS OVER THE RIDGE
AS IT SLIPS EAST...ESPECIALLY TOWARD THE END OF THE FRIDAY. THE
CENTER OF THE SFC HIGH WILL SHIFT FURTHER EAST ALSO...OFF THE MID
ATLANTIC COAST BY LATE FRI. THEREFORE DRIER NORTHERLY FLOW WILL
SHIFT TO A GREATER ON SHORE TO S-SE MOISTER RETURN FLOW THROUGH
FRI NIGHT INTO THE WEEKEND AND AIR MASS WILL BEGIN TO MODIFY.
AN OVERALL DRY AIR MASS IN PLACE WILL PRODUCE GREAT DIURNAL
SWINGS WITH LOWER DEWPOINTS DOWN CLOSE TO 50 ALLOWING OVERNIGHT
TEMPS TO DROP OFF QUICKLY DOWN TO THE 50S UNDER MAINLY CLEAR SKIES
AND LIGHT TO CALM WINDS. AFTER A RELATIVELY COOLER START TO THE
DAYS...TEMPS WILL RECOVER TO NEAR SEASONABLE VALUES UNDER MAY
SUNSHINE...INTO THE UPPER 70S MOST PLACES.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID TO UPPER RIDGE WILL SHIFT A LITTLE
BUT OVERALL WILL CONTINUE TO HOLD ON UP THROUGH THE
SOUTHEAST...PRODUCING SUBSIDENCE OVER THE AREA. THE SFC HIGH WILL
CONTINUE TO SLIP FARTHER EAST WHICH WILL PRODUCE A GREATER
SOUTHERLY RETURN FLOW OF MOISTURE WITH DEWPOINT TEMPS REACHING
BACK UP INTO AND THROUGH THE 60S DURING THE WEEKEND INTO EARLY
NEXT WEEK. SOME MID TO HIGH CLOUDS WILL CONTINUE TO RIDE OVER THE
RIDGE INTO THE AREA BUT OVERALL EXPECT A GOOD DEAL OF SUNSHINE
WITH AFTN TEMPS REACHING CLOSER TO SEASONABLE VALUES THROUGH THE
WEEKEND AND THEN ABOVE NORMAL AS HIGHER DEWPOINTS KEEP OVERNIGHT
LOWS IN THE 60S SAT NIGHT ONWARD. TEMPS DURING THE DAY WILL REACH
UP INTO THE 80S AS H5 HEIGHTS AND 850 TEMPS REMAIN ON RISING TREND
THROUGH EARLY NEXT WEEK. SUBSIDENCE ALOFT SHOULD ONLY ALLOW FOR
LOCALIZED CONVECTION TO DEVELOP MAINLY ASSOCIATED WITH THE SEA
BREEZE THROUGH MONDAY. BY TUES...THE RIDGE FLATTENS AND COLD FRONT
APPROACHES THE AREA WITH THE BEST CHC OF PCP COMING MID WEEK NEXT
WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...VFR EXPECTED THROUGH THIS TAF VALID PERIOD. KLTX
VAD WIND PROFILE INDICATES N WINDS JUST OFF THE SURFACE SO THE
COLD FRONT SOUTH OF KMYR WITHIN HE NEXT HOUR OR TWO. IT ALSO
INDICATES A SMATTERING MID CLOUD LAYERS WITH A MORE PERSISTENT
CLOUD DECK 18K-20K.
WINDS WILL BE N-NE THIS MORNING BECOMING E AT THE COASTAL
TERMINALS IN THE AFTERNOON. MID/UPPER CLOUDS WILL MOVE OFF IN THE
AFTERNOON AS A FEW/SCT LOW LEVEL CU DEVELOPS. UPPER CLOUDS RETURN
IN THE LATE EVENING AS WINDS BECOME NE FOR THE OVERNIGHT PERIOD.
NO FOG EXPECTED.
EXTENDED OUTLOOK...VFR. ISOLATED SHOWERS FRIDAY...BECOMING SCATTERED
SAT AND SUN. BETTER CHANCES FOR CONVECTION MON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...THE COLD FRONT EXTENDS FROM JACKSONVILLE
NC...TO WHITEVILLE TO SOUTH OF FLORENCE SC...AND SHOULD FINALLY MAKE
ITS WAY OFF THE BEACHES A COUPLE HOURS AFTER SUNRISE...SHIFTING WEST
WINDS TO THE NORTH. IT STILL APPEARS THERE WILL BE LITTLE NORTHERLY
SURGE BEHIND THE FRONT: UPSTREAM OBSERVATIONS SHOW LITTLE INCREASE
IN WIND SPEED...SUPPORTING THE 00Z NAM SOLUTION OVER THE 00Z GFS. IN
FACT THE 00Z GFS APPEARS TO HAVE HAD PROBLEMS THIS MORNING WITH A
TOO-RAPID FRONTAL PASSAGE AND ODD WIND DIRECTIONS THROUGHOUT THE DAY
COMPARED TO THE REST OF THE MODELS. FOR WINDS I HAVE STAYED CLOSER
THE 00Z NAM AS A RESULT.
ONCE THE FRONT MOVES THROUGH NORTH WINDS ARE EXPECTED THIS
MORNING...VEERING NE THIS AFTERNOON. A WEAK SEABREEZE MAY TURN
NEARSHORE DIRECTIONS EASTERLY. HIGH PRESSURE WILL BUILD EAST ACROSS
THE GREAT LAKES TONIGHT WITH OUR WINDS TURNING MORE EASTERLY WITH
TIME.
SEAS CURRENTLY 3-4 FEET AWAY FROM THE COAST WILL FALL TO 2-3 FT THIS
AFTERNOON...BUT MAY BUILD AGAIN LATE TONIGHT AS EAST-NORTHEAST WINDS
INCREASE IN SPEED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE BUILDING DOWN FROM THE
NORTH WILL SHIFT EAST THROUGH THE PERIOD EVENTUALLY SHIFTING OFF
THE MID ATLANTIC COAST ON FRI. NORTHEASTERLY FLOW UP TO 15 KTS ON
THE FRONT END WILL LIGHTEN AND VEER AROUND BECOMING MORE NORTHEAST
TO EAST THROUGH THURS AND THEN E-SE FRI NIGHT INTO THE WEEKEND.
SEAS WILL BASICALLY REMAIN IN THE 2 TO 4 FT RANGE.
.LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SHIFT OFFSHORE EARLY
IN THE WEEKEND PRODUCING A SOUTHEASTERLY ON SHORE FLOW LESS THAN
15 KTS. A SEA BREEZE WILL DEVELOP EACH AFTERNOON ADDING TO THE SE
PUSH AND PRODUCING GUSTY ON SHORE WINDS AND SOME CHOP IN THE NEAR
SHORE WATERS EACH AFTERNOON. OVERALL EXPECT SEAS IN THE 2 TO 4 FT
RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
648 AM EDT WED MAY 13 2015
.SYNOPSIS...
LESS HUMID AIR WILL ARRIVE TODAY AND SHOULD LAST INTO EARLY FRIDAY AS
HIGH PRESSURE BUILDS DOWN FROM THE NORTH. THE LATTER PART OF THE
WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND
THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...THE COLD FRONT RUNS FROM NEAR JACKSONVILLE
NC TO NEAR WHITEVILLE TO SOUTH OF FLORENCE SC. THIS IS STILL SLOWER
THAN ANY MODEL SHOWED JUST FIVE HOURS AGO...BUT IT APPEARS THE
LATEST HRRR MODEL HAS A REASONABLE HANDLE ON THE MOVEMENT OF THIS
FEATURE OVER THE NEXT FEW HOURS. THE 00Z GFS APPEARS TO HAVE HAD
PROBLEMS THIS MORNING WITH A TOO-RAPID FRONTAL PASSAGE AND ODD WIND
DIRECTIONS THROUGHOUT THE DAY COMPARED TO THE REST OF THE MODELS.
FOR WINDS AND TEMPERATURES I HAVE STAYED CLOSER THE 00Z NAM AS A
RESULT.
SHOWER CHANCES ARE QUITE LOW THROUGH THE MORNING. FORECAST SOUNDINGS
SHOW A SMALL REGION OF CONDITIONAL INSTABILITY BASED ABOVE THE
SURFACE WHICH COULD GENERATE AN ISOLATED SHOWER UP THROUGH THE TIME
OF FRONTAL PASSAGE. HOWEVER GIVEN POOR FORCING AND INCREASING
LIMITED VERTICAL MOISTURE...ODDS OF DEVELOPING SHOWERS ARE LESS THAN
10 PERCENT...AND WILL NOT BE MENTIONED IN THE FORECAST.
CONSIDERABLE CIRRUS CLOUDINESS WILL HANG AROUND THROUGH THE MORNING.
GLANCING OUT IN THE NWS OFFICE PARKING LOT THE CLOUDS ARE FAIRLY
OPAQUE BUT HAVE ENOUGH BREAKS AND THIN SPOTS TO LET ENOUGH SUN
THROUGH TO BOOST TEMPERATURES INTO THE UPPER 70S BY NOON. NEARLY
FULL SUNSHINE SHOULD DEVELOP THIS AFTERNOON AS THE CIRRUS ADVECTS
OFFSHORE...AND HIGHS SHOULD REACH 79-84 AWAY FROM THE BEACHES.
LINEAR MOTION EXTRAPOLATION ON THE BACK EDGE OF THE CLOUDS BRINGS IT
TO FLORENCE AROUND NOON...AND WILMINGTON AROUND 2 PM.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SETTLE DOWN OVER THE
CAROLINAS FROM THE NORTH AS MID TO UPPER RIDGE ALIGNS ITSELF UP
THE EAST COAST THURS INTO FRI. OVERALL EXPECT A RAIN FREE PERIOD
WITH PLENTY OF DRY AIR AND SUBSIDENCE THROUGH THE MID LEVELS OF
THE ATMOSPHERE. MAY SEE SOME FLAT CU DEVELOPING WITH HEATING OF
THE DAY AIDED BY SOME CONVERGENCE ALONG SEA BREEZE BUT STRONG
SUBSIDENCE INVERSION WILL NOT ALLOW MUCH DEPTH TO ANY CU. ALTHOUGH
SUNSHINE SHOULD BE QUITE PLENTIFUL THROUGH THE PERIOD...SOME
HIGHER LEVEL CLOUDS WILL SPREAD INTO THE CAROLINAS OVER THE RIDGE
AS IT SLIPS EAST...ESPECIALLY TOWARD THE END OF THE FRIDAY. THE
CENTER OF THE SFC HIGH WILL SHIFT FURTHER EAST ALSO...OFF THE MID
ATLANTIC COAST BY LATE FRI. THEREFORE DRIER NORTHERLY FLOW WILL
SHIFT TO A GREATER ON SHORE TO S-SE MOISTER RETURN FLOW THROUGH
FRI NIGHT INTO THE WEEKEND AND AIR MASS WILL BEGIN TO MODIFY.
AN OVERALL DRY AIR MASS IN PLACE WILL PRODUCE GREAT DIURNAL
SWINGS WITH LOWER DEWPOINTS DOWN CLOSE TO 50 ALLOWING OVERNIGHT
TEMPS TO DROP OFF QUICKLY DOWN TO THE 50S UNDER MAINLY CLEAR SKIES
AND LIGHT TO CALM WINDS. AFTER A RELATIVELY COOLER START TO THE
DAYS...TEMPS WILL RECOVER TO NEAR SEASONABLE VALUES UNDER MAY
SUNSHINE...INTO THE UPPER 70S MOST PLACES.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID TO UPPER RIDGE WILL SHIFT A LITTLE
BUT OVERALL WILL CONTINUE TO HOLD ON UP THROUGH THE
SOUTHEAST...PRODUCING SUBSIDENCE OVER THE AREA. THE SFC HIGH WILL
CONTINUE TO SLIP FARTHER EAST WHICH WILL PRODUCE A GREATER
SOUTHERLY RETURN FLOW OF MOISTURE WITH DEWPOINT TEMPS REACHING
BACK UP INTO AND THROUGH THE 60S DURING THE WEEKEND INTO EARLY
NEXT WEEK. SOME MID TO HIGH CLOUDS WILL CONTINUE TO RIDE OVER THE
RIDGE INTO THE AREA BUT OVERALL EXPECT A GOOD DEAL OF SUNSHINE
WITH AFTN TEMPS REACHING CLOSER TO SEASONABLE VALUES THROUGH THE
WEEKEND AND THEN ABOVE NORMAL AS HIGHER DEWPOINTS KEEP OVERNIGHT
LOWS IN THE 60S SAT NIGHT ONWARD. TEMPS DURING THE DAY WILL REACH
UP INTO THE 80S AS H5 HEIGHTS AND 850 TEMPS REMAIN ON RISING TREND
THROUGH EARLY NEXT WEEK. SUBSIDENCE ALOFT SHOULD ONLY ALLOW FOR
LOCALIZED CONVECTION TO DEVELOP MAINLY ASSOCIATED WITH THE SEA
BREEZE THROUGH MONDAY. BY TUES...THE RIDGE FLATTENS AND COLD FRONT
APPROACHES THE AREA WITH THE BEST CHC OF PCP COMING MID WEEK NEXT
WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...THE COLD FRONT SHOULD MOVE OFF THE COAST AROUND 10Z. AN
ISOLATED SHOWER CAN NOT BE RULED OUT...BUT IT IS A REMOTE
POSSIBILITY. POST FRONTAL...LOOK FOR NORTHERLY WINDS AROUND 10 KTS
WITH A MID CLOUD CEILING WORST CASE. AFTER DAYBREAK...VFR CONTINUES.
WINDS WILL VEER TO THE NORTHEAST BY MID MORNING...BECOMING EASTERLY
ALONG THE COAST IN THE AFTERNOON.
EXTENDED OUTLOOK...VFR. ISOLATED SHOWERS FRIDAY...BECOMING SCATTERED
SAT AND SUN. BETTER CHANCES FOR CONVECTION MON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...THE COLD FRONT EXTENDS FROM JACKSONVILLE
NC...TO WHITEVILLE TO SOUTH OF FLORENCE SC...AND SHOULD FINALLY MAKE
ITS WAY OFF THE BEACHES A COUPLE HOURS AFTER SUNRISE...SHIFTING WEST
WINDS TO THE NORTH. IT STILL APPEARS THERE WILL BE LITTLE NORTHERLY
SURGE BEHIND THE FRONT: UPSTREAM OBSERVATIONS SHOW LITTLE INCREASE
IN WIND SPEED...SUPPORTING THE 00Z NAM SOLUTION OVER THE 00Z GFS. IN
FACT THE 00Z GFS APPEARS TO HAVE HAD PROBLEMS THIS MORNING WITH A
TOO-RAPID FRONTAL PASSAGE AND ODD WIND DIRECTIONS THROUGHOUT THE DAY
COMPARED TO THE REST OF THE MODELS. FOR WINDS I HAVE STAYED CLOSER
THE 00Z NAM AS A RESULT.
ONCE THE FRONT MOVES THROUGH NORTH WINDS ARE EXPECTED THIS
MORNING...VEERING NE THIS AFTERNOON. A WEAK SEABREEZE MAY TURN
NEARSHORE DIRECTIONS EASTERLY. HIGH PRESSURE WILL BUILD EAST ACROSS
THE GREAT LAKES TONIGHT WITH OUR WINDS TURNING MORE EASTERLY WITH
TIME.
SEAS CURRENTLY 3-4 FEET AWAY FROM THE COAST WILL FALL TO 2-3 FT THIS
AFTERNOON...BUT MAY BUILD AGAIN LATE TONIGHT AS EAST-NORTHEAST WINDS
INCREASE IN SPEED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE BUILDING DOWN FROM THE
NORTH WILL SHIFT EAST THROUGH THE PERIOD EVENTUALLY SHIFTING OFF
THE MID ATLANTIC COAST ON FRI. NORTHEASTERLY FLOW UP TO 15 KTS ON
THE FRONT END WILL LIGHTEN AND VEER AROUND BECOMING MORE NORTHEAST
TO EAST THROUGH THURS AND THEN E-SE FRI NIGHT INTO THE WEEKEND.
SEAS WILL BASICALLY REMAIN IN THE 2 TO 4 FT RANGE.
.LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE WILL SHIFT OFFSHORE EARLY
IN THE WEEKEND PRODUCING A SOUTHEASTERLY ON SHORE FLOW LESS THAN
15 KTS. A SEA BREEZE WILL DEVELOP EACH AFTERNOON ADDING TO THE SE
PUSH AND PRODUCING GUSTY ON SHORE WINDS AND SOME CHOP IN THE NEAR
SHORE WATERS EACH AFTERNOON. OVERALL EXPECT SEAS IN THE 2 TO 4 FT
RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
127 AM EDT WED MAY 13 2015
.SYNOPSIS...
LESS HUMID AIR WILL ARRIVE TODAY BEHIND A COLD FRONT AND SHOULD LAST
INTO THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF
THE WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND
THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 120 AM WEDNESDAY...I HAVE RAISED FORECAST LOWS BY SEVERAL
DEGREES ALONG THE COAST. FROPA SHOULD NOT OCCUR UNTIL 5:00-5:30 AM
AT THE BEACHES WHICH LEAVES ONLY A SHORT WINDOW FOR ANY SIGNIFICANT
RADIATIONAL/ADVECTIVE COOLING TO OCCUR BEFORE SUNRISE. RADAR HAS
CLEARED OUT...ALTHOUGH THE LATEST FEW HRRR RUNS STILL INDICATE SOME
LINGERING SHOWER POTENTIAL UP THROUGH FROPA ACROSS SE NORTH
CAROLINA. I HAVE REMOVED THUNDER AS THERE IS A STABLE ENOUGH
INVERSION ALOFT TO RULE OUT DEEP CONVECTION OVER LAND. DISCUSSION
FROM 1030 PM TUESDAY FOLLOWS...
BASED ON LATEST SHOWER AND TSTORM ACTIVITY AND COVERAGE...LOW CHANCE
POPS TO CONTINUE AHEAD OF THE APPROACHING COLD FRONT...AND THAT IS
BEING GENEROUS. CLOUDS AND CONVECTION TO QUICKLY CLEAR OUT AFTER THE
CFP. ALSO...THOSE MISERABLE 70+ DEGREE DEWPOINTS TO MIGRATE AWAY
FROM THE FA AFTER FROPA. WE HAVE THE WHOLE SUMMER AHEAD TO
EXPERIENCE THOSE 70+ DEGREE DEWPOINTS. THE THREAT FOR ANY SEVERE
ACTIVITY HAS BEEN NEGATED. CURRENT MIN TEMP FORECAST STILL AOK.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS
OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES
OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL
TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S
MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER
70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS
OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP
THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST
TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION.
MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES
OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS
WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN
INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY
APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER
THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A
BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD
RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS
FOR MIDDLE MAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH MONDAY/...
AS OF 06Z...THE COLD FRONT SHOULD MOVE OFF THE COAST AROUND 10Z. AN
ISOLATED SHOWER CAN NOT BE RULED OUT...BUT IT IS A REMOTE
POSSIBILITY. POST FRONTAL...LOOK FOR NORTHERLY WINDS AROUND 10 KTS
WITH A MID CLOUD CEILING WORST CASE. AFTER DAYBREAK...VFR CONTINUES.
WINDS WILL VEER TO THE NORTHEAST BY MID MORNING...BECOMING EASTERLY
ALONG THE COAST IN THE AFTERNOON.
EXTENDED OUTLOOK...VFR. ISOLATED SHOWERS FRIDAY...BECOMING SCATTERED
SAT AND SUN. BETTER CHANCES FOR CONVECTION MON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 120 AM WEDNESDAY...RAISED WIND SPEEDS A BIT FROM NOW UP UNTIL
THE COLD FRONT ARRIVES AT THE BEACHES AROUND 5-6 AM. OFFSHORE IT`S
GUSTING TO 25 KT AT FRYING PAN SHOALS..WITH 10-15 KT GUSTS AT THE
BEACHES. ALSO RAISED NEARSHORE WAVE HEIGHT FORECASTS TO FIT
CONCEPTUAL MODELS OF ONSHORE/LONGSHORE WINDS AND 3-4 FOOT SEAS AT 5-
20 MILE DISTANCES OFFSHORE. DISCUSSION FROM 1030 PM TUESDAY
FOLLOWS...
SSW-SW WINDS 15 TO 20 KT TO PREVAIL WELL INTO TONIGHT...DIMINISHING
TO 10-15 KT AS THE COLD FRONT APPROACHES...AND LIKELY VEERING TO THE
NW-N AROUND 15 KT BY DAYBREAK WED AFTER FROPA. SIGNIFICANT SEAS WILL
RUN 2 TO 4 FT...HIGHEST ACROSS THE WATERS FROM CAPE FEAR SOUTH TO
LITTLE RIVER INLET WHERE THE FETCH IS GREATEST GIVEN THE WIND
DIRECTION. A 1 TO 2 FOOT 7-8 SECOND PERIOD GROUND SWELL REMAINS
IDENTIFIABLE...BUT WIND DRIVEN WAVES AT 4 TO 5 SECONDS WILL DOMINATE
THE SIGNIFICANT SEAS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A
WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE
HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS
TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE
NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO
TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED
WED/THU/
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE
PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL
BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING
DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS
TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED
SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S
AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC/TRA
NEAR TERM...TRA
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...DL/TRA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
330 PM CDT WED MAY 13 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM CDT WED MAY 13 2015
MAIN CHALLENGE TONIGHT WILL BE THE LINGERING PCPN CHANCES. AS OF
LATE AFTERNOON THE WARM FRONT REMAINED ALONG THE INTERSTATE 94
CORRIDOR IN ND AND THE HIGHWAY 10 CORRIDOR IN MN. THE PERSISTENT
SHOWERS/ISOLATED THUNDER CONTINUED JUST NORTH OF THIS SFC
BOUNDARY. REGIONAL RADAR SHOWS THIS LINE EXTENDING FROM NORTH OF
KDLH ALL THE WAY BACK THROUGH KBIS. WATER VAPOR LOOP STILL SHOWS A
COUPLE OF WAVES BACK OVER THE SOUTHWESTERN US WHICH WILL LIFT
NORTHEAST OVER THE NEXT DAY OR TWO. ONE WAVE EJECTS OUT TONIGHT
TOWARD THE KBIS AREA. AT THE SFC IT APPEARS A WEAK LOW SETS UP
OVER WESTERN SD WITH AN INVERTED TROUGH UP THRU KBIS INTO
NORTHEAST ND. STRONG 850MB FLOW CONTINUES TO IMPINGE ON THIS
BOUNDARY. HIGH RESOLUTION MODELS DID NOT HANDLE TODAYS EVENT WELL
AT ALL...AND THEY SET THIS BOUNDARY UP FROM KBIS TO KDVL TONIGHT.
THEREFORE CONFIDENCE NOT ALL THAT HIGH AT THIS POINT. EITHER
WAY...WITH THE POTENTIAL FOR A STAGNANT SFC BOUNDARY AND UPPER
FLOW PARALLEL TO IT...COULD BE SOME PERSISTENT RAIN LIKE THERE WAS
TODAY. HOWEVER IF IT FALLS OVER THE KDVL AREA INTO NORTHEAST ND IT
WOULD FALL WHERE THERE HAS BEEN LESS RAIN. IF IT FALLS FURTHER
SOUTH IT COULD RESULT IN MORE PROBLEMS...AS THAT AREA HAS HAD MORE
RAIN. ON THURSDAY THE MODELS KEEP MOST OF THE RAIN ACROSS
NORTHEAST ND...WITH THE POTENTIAL FOR ANOTHER HEAVIER BAND TO LIFT
UP INTO WEST CENTRAL MN. THIS SECOND BAND WOULD BE SUPPORTED BY
ANOTHER WAVE LIFTING UP INTO THAT AREA AND THE STEADY 850MB JET.
IN BETWEEN THERE COULD BE MORE SPOTTY PCPN. THIS BAND SHOULD
SLOWLY SHIFT EAST THU NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED MAY 13 2015
FRIDAY LOOKS LIKE THE ONLY DRY DAY AT THIS POINT WITH MORE PCPN
ARRIVING BY FRI NIGHT/SAT. MODELS STILL DIFFER AT THIS POINT WITH
THIS NEXT EVENT...SOME HAVING BROAD PCPN OVER A WIDER AREA AND
SOME TARGETING CENTRAL AND NORTHEAST ND AGAIN.
SATURDAY NIGHT THROUGH WEDNESDAY... ON SATURDAY NIGHT...A STRONG
UPPER LEVEL WAVE WILL BE APPROACHING FROM THE SSW. A LOW PRESSURE
SYSTEM WILL LIKELY EXIST OVER SD WITH AN INVERTED TROUGH INTO
CENTRAL ND AND A WARM FRONT POSSIBLY EXTENDING EAST THROUGH THE RRV.
THE GFS HAS 1000-2000 J/KG OF CAPE WITH AROUND 30 KTS OF DEEP
SHEAR...WHICH POINTS TOWARDS ORGANIZED THUNDERSTORMS. ALSO...THE SPC
HAS THE SOUTHERN CWA INCLUDED IN THEIR DAY 4 SEVERE WEATHER OUTLOOK.
THE ECMWF IS GENERALLY SIMILAR. HAVE INCLUDED A MENTION OF SHOWERS
AND THUNDERSTORMS SATURDAY EVENING...TAPERING OFF TO ISOLATED
THUNDERSTORM COVERAGE AFTER MIDNIGHT. SHOWERS/THUNDERSTORMS WILL
CONTINUE INTO SUNDAY AS THE SURFACE LOW AND UPPER LEVEL SHORT WAVE
MOVE THROUGH THE REGION. THIS WEEKEND WILL LIKELY SEE SIGNIFICANT
RAINFALL CHANCES AGAIN ACROSS THE AREA.
DRY AND COOL HIGH PRESSURE WILL MOVE INTO THE AREA FOR MONDAY. THE
SURFACE HIGH WILL SLOWLY DRIFT THROUGH THE AREA ON TUESDAY...WITH
THE MODELS DIFFERING ON THE UPPER PATTERN BY WEDNESDAY. THE GFS
STARTS TO BRING A LOW PRESSURE SYSTEM ACROSS SD...WHILE THE ECMWF
HAS A MUCH WEAKER FEATURE. THIS UPDATE WILL HAVE SOME PRECIPITATION
IN THE FORECAST FOR MIDWEEK...BUT IF MODELS TREND TOWARD THE
ECMWF...A DRIER FORECAST WILL BE NEEDED WITH THE NEXT UPDATE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 106 PM CDT WED MAY 13 2015
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO EXIST ACROSS SE ND/W
CTRL MN TODAY. LIGHTNING HAS ENDED...SO HAVE CONTINUED WITH JUST
SHRA MENTION AT KFAR. INDIVIDUAL CELLS ARE MOVING ENE...WHILE THE
LINE SLOWLY DRIFTS NORTHWARD. NAM MODEL HAS ENOUGH INSTABILITY TO
SUPPORT THUNDERSTORMS THIS AFTERNOON AT THE ND TAF SITES...BUT BASED
ON CURRENT TRENDS...WILL LEAVE OUT THUNDER MENTION. ALSO HRRR MODEL
BRINGS PRECIP NORTHWARD THROUGH KBJI/KGFK/KTVF THIS AFTERNOON...
TRENDS DON`T FAVOR THIS...SO WILL NOT INLCUDE BUT MONITOR AND UPDATE
AS NEEDED. TONIGHT...CIGS CRASH BACK DOWN AS NEXT LOW PRESSURE
SYSTEM APPROACHES. MAV/MET GUIDANCE BOTH POINT TOWARD IFR CIGS AND
MVFR VIS BY SUNRISE. HAVE INCLUDED IFR CIGS AT MOST SITES AROUND
12Z. SHOWERS ARE EXPECTED LATER TONIGHT...WITH THUNDER NOT LIKELY
BUT A POSSIBILITY IN ND.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...GODON
LONG TERM...GODON/KNUTSVIG
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
106 PM CDT WED MAY 13 2015
.UPDATE...
ISSUED AT 1240 PM CDT WED MAY 13 2015
STILL HAVE THE LINE OF SHOWERS ALONG INTERSTATE 94 IN ND AND
HIGHWAY 10 IN MN...AND IT HAS TRANSITIONED MORE TO ISOLATED
THUNDER NOW. OVERALL IT HAS NOT SHOWN MUCH MOVEMENT. LATEST HIGH
RESOLUTION MODELS WANT TO LIFT THIS NORTHWARD...WHICH SO FAR HAS
NOT BEEN HAPPENING. ONLY OTHER ISSUE IS THE STRONGER WIND GUSTS
ACROSS THE FAR SOUTHERN RED RIVER VALLEY. THE STRONGEST WINDS
HAVE BEEN AT KFAR AND ARE LIKELY AIDED BY THE SHOWERS. SEEING SOME
STRONGER WINDS ALSO COMING DOWN THE SISSETON HILLS...WHICH WILL
LIKELY CONTINUE INTO THE AFTERNOON. THEREFORE ISSUED A WIND
ADVISORY FOR A FEW HOURS THIS AFTERNOON. SINCE THE BOUNDARY WITH
THE SHOWERS HAS NOT MOVED MUCH...TEMPS AND CLOUDS ARE HANGING
WHERE THEY ARE AT TOO. IF IT CAN CLEAR ACROSS THE FAR
SOUTH...TEMPS SHOULD RISE QUICKLY THERE.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 325 AM CDT WED MAY 13 2015
ACTIVE PATTERN CONTINUES. FORECAST CHALLENGE CONCERNS
RAIN/THUNDER CHANCES AND TEMPERATURES. MODELS IN PRETTY GOOD
AGREEMENT THROUGH THE PERIOD. WITH NO REAL PREFERENCE WILL USE
BLEND.
CURRENT AREA OF SHRA ASSOCIATED WITH MID LEVEL FRONTOGENETIC
FORCING/ISENTROPIC LIFT LIFTING NE THROUGH THE SW HALF OF THE FA.
AT THIS POINT BAND NOT VERY IMPRESSIVE HOWEVER ALL MODELS SHOW
MORE ORGANIZATION DURING THE COURSE OF THE DAY AS BAND LIFTS NE.
MAIN BAND WILL BE OVER THE NE HALF THIS AFTERNOON HOWEVER THERE
STILL REMAINS SOME LIFT FARTHER TO THE SW CLOSER TO LOW LEVEL
BOUNDARY SO WILL MAINTAIN GENERAL CHANCE POPS. WARM ADVECTION
CONTINUES TO LIFT NORTH WITH WARMEST TEMPERATURES ACROSS THE
SOUTH. DEGREE OF CLOUD COVER WILL HAVE BIG IMPACT ON TEMPERATURES
BUT BEST POTENTIAL FOR SOLAR SHOULD BE ACROSS THE SOUTH WITH
COOLER TEMPERATURES HEADING NE VCNTY CLOUDS PCPN.
MORE SIGNIFICANT SHORT WAVE WILL EJECT NE FROM WESTERN TROUGH
LATER TONIGHT. EXPECT A MORE ORGANIZED AREA OF RAIN TO LIFT NE
LATE TONIGHT THROUGH THURSDAY ALONG AND BEHIND ASSOCIATED SURFACE
LOW AND INVERTED TROUGH. BASED ON BOUNDARY POSITION BEST POTENTIAL
FOR SIGNIFICANT RAINFALL LOOKS TO BE FROM THE WESTERN FA INTO THE
NORTHERN VALLEY. WITH MODEST LOW LEVEL JET CONVERGENCE...SHOWALTERS
SUB ZERO AND A BIT OF ELEVATED CAPE COULD SEE SOME THUNDER MAINLY
FROM VALLEY WEST TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 325 AM CDT WED MAY 13 2015
AS WAVE LIFTS NE PCPN SHOULD END FROM SW TO NORTHEAST THURSDAY
NIGHT. FRIDAY LOOKS TO BE DRY BEFORE RAIN CHANCES RETURN LATE
FRIDAY NIGHT AS UPPER LOW LIFTS NE. TEMPERATURES SHOULD BE CLOSER
TO AVERAGE.
SATURDAY TO TUESDAY...MODELS IN FAIR AGREEMENT WITH THE OVERALL
SYNOPTIC FEATURES...TIMING AND EXACT PLACEMENT STILL TO BE
DETERMINED AND THE MAJOR PLAYER IN PRECIP AMOUNTS. ACTIVE PERIOD
CONTINUES THIS WEEKEND WITH 500MB UPPER LOW AND ASSOCIATED SFC
SYSTEM TO MOVE ACROSS THE NORTHERN PLAINS. SHOWERS AND THUNDERSTORMS
EXPECTED TO DEVELOP IN EARNEST SATURDAY MORNING IN THE SOUTHERN FA
AND LIFT TO THE NORTH WITH STRONG 850MB MOISTURE AND WARM AIR
ADVECTION ON THE NOSE OF THE 40KT SOUTHERLY LOW LEVEL JET. 00Z EC
AND GFS BRING SFC LOW INTO SE ND BY 12Z SUNDAY AND WRAP DEFORMATION
ZONE PRECIP ACROSS THE DEVILS LAKE BASIN SUNDAY. WITH PWATS OVER AN
INCH AND STRONG FORCING IN THE VICINITY OF THE UPPER LOW EXPECTING
ANOTHER EFFICIENT RAIN MAKING SYSTEM AND SIGNIFICANT RAINFALL AMOUNTS
OVER THE SATURDAY TO MONDAY TIME FRAME...1 TO 2 INCHES POSSIBLE WITH
THE HIGHER CONFIDENCE AREA OVER THE DEVILS LAKE BASIN. A FEW SNOW
FLAKES MAY MIX IN SUNDAY NIGHT. TEMPERATURES FOR THE PERIOD WILL BE
WARMEST SATURDAY INTO THE 60S AND 70S. SUNDAY WILL BE DEPENDENT ON
THE PLACEMENT OF THE FRONT WITH 60S AHEAD AND 40S ON THE
BACKSIDE...COOL MONDAY AND TUESDAY IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 106 PM CDT WED MAY 13 2015
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO EXIST ACROSS SE ND/W
CTRL MN TODAY. LIGHTNING HAS ENDED...SO HAVE CONTINUED WITH JUST
SHRA MENTION AT KFAR. INDIVIDUAL CELLS ARE MOVING ENE...WHILE THE
LINE SLOWLY DRIFTS NORTHWARD. NAM MODEL HAS ENOUGH INSTABILITY TO
SUPPORT THUNDERSTORMS THIS AFTERNOON AT THE ND TAF SITES...BUT BASED
ON CURRENT TRENDS...WILL LEAVE OUT THUNDER MENTION. ALSO HRRR MODEL
BRINGS PRECIP NORTHWARD THROUGH KBJI/KGFK/KTVF THIS AFTERNOON...
TRENDS DON`T FAVOR THIS...SO WILL NOT INLCUDE BUT MONITOR AND UPDATE
AS NEEDED. TONIGHT...CIGS CRASH BACK DOWN AS NEXT LOW PRESSURE
SYSTEM APPROACHES. MAV/MET GUIDANCE BOTH POINT TOWARD IFR CIGS AND
MVFR VIS BY SUNRISE. HAVE INCLUDED IFR CIGS AT MOST SITES AROUND
12Z. SHOWERS ARE EXPECTED LATER TONIGHT...WITH THUNDER NOT LIKELY
BUT A POSSIBILITY IN ND.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ039-053.
MN...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ003-029.
&&
$$
UPDATE...GODON
SHORT TERM...VOELKER
LONG TERM...JK/VOELKER
AVIATION...KNUTSVIG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1255 AM CDT WED MAY 13 2015
.UPDATE...
ISSUED AT 1256 AM CDT WED MAY 13 2015
BAND OF SHOWER EXTENDED FROM AROUND MINOT EASTWARD TO RUGBY/DEVILS
LAKE AND SHOULD CONTINUE MOVING NORTHWARD EARLY THIS MORNING TOWARD
THE CANADIAN BORDER. OTHER MORE ISOLATED SHOWERS IN SOUTHEASTERN
MONTANA AND WESTERN SOUTH DAKOTA WERE MOVING NORTHEASTWARD INTO
BOWMAN COUNTY...AND KEPT A CHANCE/SLIGHT CHANCE OF SHOWERS FOR MUCH
OF WESTERN AND CENTRAL NORTH DAKOTA. SHORT TERM MODELS HANDLING THE
NORTHERN BAND OF SHOWERS WELL...AND MORE ISOLATED SHOWERS SOUTHWEST
ARE ASSOCIATED WITH SMALL UPPER LEVEL ENERGY IMPULSES MOVING
NORTHEAST OUT OF THE CENTRAL ROCKIES. SURFACE LOW OVER WYOMING WITH
A TIGHTENING PRESSURE GRADIENT WAS ASSOCIATED WITH INCREASING
EASTERLY WINDS OVER SOUTHWEST/SOUTH CENTRAL NORTH DAKOTA...SO
INCREASED WINDS THIS AREA A BIT FOR THE OVERNIGHT HOURS. TEMPERATURE
TREND ON TRACK.
UPDATE ISSUED AT 938 PM CDT TUE MAY 12 2015
AT 930 PM CDT...BAND OF SHOWERS CONTINUES TO TREND NORTH AND EAST
NOW ALONG A LAKE SAKAKAWEA SOUTHEAST INTO JAMESTOWN LINE. WILL
TREND THE HIGHER POPS SLOWLY EAST NORTHEAST THROUGH THE REMAINDER
OF THE EVENING. AFTER MIDNIGHT MODELS DEPICT LIFT OVER A WARM
FRONT ACROSS SOUTH DAKOTA THAT WILL FAVOR INCREASED CLOUDS AND
SCATTERED SHOWERS OVER THE REGION AS THE CURRENT FORECAST HAS
GOING.
UPDATE ISSUED AT 654 PM CDT TUE MAY 12 2015
BAND OF RAIN SHOWERS MOVING THROUGH CENTRAL NORTH DAKOTA. UPDATED
THE POPS/SKY GRIDS BASED ON THESE HRRR TRENDS. FOCUSED HIGHEST
POPS EAST OF BISMARCK FOR THE EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 259 PM CDT TUE MAY 12 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE PRECIPITATION
CHANCES THROUGH THE PERIOD.
CURRENTLY...ZONAL FLOW ALOFT WITH A CLOSED MID LEVEL LOW OVER FAR
SOUTH CENTRAL CANADA AND A RIDGE AXIS STRETCHING FROM THE CENTRAL
PLAINS NORTHWEST INTO SOUTHERN MONTANA. EMBEDDED S/WV IMPULSE
MOVING ALONG THE ND/SD BORDER WILL BRING A DECENT CHANCE FOR
SHOWERS TO SOUTHERN PORTIONS OF NORTH DAKOTA THIS AFTERNOON AND
EVENING. EXPECT MOISTURE TO REMAIN BELOW A TENTH OF AN INCH...WITH
MOST LOCATIONS SEEING A TRACE OR PERHAPS A FEW HUNDREDTHS.
CLOUDS AND CHANCES FOR SHOWERS CONTINUE TONIGHT WITH MODELS
DEPICTING SEVERAL SMALL-SCALE EMBEDDED WAVES PUSHING EAST ACROSS
THE REGION ALONG WITH A PERSISTENT AND MOIST EAST/SOUTHEASTERLY
LOW/MID LEVEL FLOW REGIME. MODELS ARE KEYING IN ON MY NORTH
CENTRAL AND EAST TONIGHT FOR BEST CHANCES AND HIGHEST MOISTURE
WHERE BEST FORCING WILL RESIDE. LOWS TONIGHT MAINLY IN THE 40S.
FOR WEDNESDAY...WARM FRONTAL BOUNDARY NOW OVER SOUTHERN SOUTH
DAKOTA WILL LIFT SLOWLY NORTH LATER TONIGHT INTO
WEDNESDAY...REACHING THE ND/SD BORDER MID TO LATE AFTERNOON. ALONG
THE WARM FRONT MUCAPE 500-1200 J/KG WILL SLOWLY CREEP INTO MY FAR
SOUTHWEST AND FAR SOUTH CENTRAL COUNTIES. 0-6KM SHEAR MODEST AT
25-35KTS DEPENDING ON WHICH MODELS IS USED. SO THERE APPEARS TO BE
SOME POTENTIAL FOR STRONG CONVECTION AND WILL BE WORTH LOOKING
MORE CLOSELY AT OVER THE NEXT 12-18 HOURS TO SEE HOW MODELS
TREND.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 259 PM CDT TUE MAY 12 2015
UNSETTLED WEATHER REMAINS ON TRACK WITH RAIN SHOWERS AND A CHANCE OF
THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY...FOLLOWED BY A BRIEF
BREAK THURSDAY NIGHT THROUGH MOST OF FRIDAY. THEN A SIGNIFICANT
WEATHER SYSTEM/VERTICALLY STACKED AND SLOW MOVING OVER THE WEEKEND
LOOKS TO PRODUCE WIDESPREAD RAIN SHOWERS AND POSSIBLY SEVERE
THUNDERSTORMS. DRIER WEATHER MONDAY AND TUESDAY.
WEDNESDAY NIGHT THROUGH THURSDAY...A 700MB UPPER LOW WITH A SURFACE
REFLECTION/WARM FRONT STRETCHING FROM CENTRAL SOUTH DAKOTA INTO
SOUTH CENTRAL NORTH DAKOTA WILL SHIFT EAST THROUGH THURSDAY. HIGH
CHANCE TO LIKELY POPS ACROSS CENTRAL NORTH DAKOTA WITH CHANCES
DECREASING FARTHER WEST. MOST UNSTABLE CAPE ACROSS SOUTHWEST INTO
SOUTH CENTRAL NORTH DAKOTA AROUND 500 J/KG WITH 0-6KM BULK SHEAR
EARLY WEDNESDAY NIGHT AT AROUND 25-30KT...THEN DECREASING THE REST
OF WEDNESDAY NIGHT INTO THURSDAY. WILL CONTINUE TO MENTION A CHANCE
FOR THUNDERSTORMS WEDNESDAY NIGHT BUT LEAVE OUT ANY MENTION ON
THURSDAY.
THURSDAY NIGHT THROUGH FRIDAY...A TRANSITORY MID LEVEL RIDGE SLIDES
THROUGH CENTRAL NORTH DAKOTA FRIDAY AFTERNOON ALLOWING MOISTURE AND
THE NEXT POTENT MID/UPPER LEVEL SHORTWAVE IN WYOMING TO IMPINGE
ACROSS SOUTHWESTERN NORTH DAKOTA FRIDAY AFTERNOON. CAPE VALUES
FORECAST NEAR 1000 J/KG IN THE FAR SOUTHWEST WITH AROUND 25KT OF 0-
6KM BULK SHEAR. HENCE WILL MENTION A CHANCE OF THUNDERSTORMS IN THIS
AREA FRIDAY AFTERNOON WITH SHOWERS ELSEWHERE IN THE WEST AND
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...A POTENT CLOSED/VERTICALLY
STACKED UPPER LOW IS FORECAST TO TRANSLATE FROM SOUTHEAST MONTANA
FRIDAY NIGHT...ACROSS NORTHERN SOUTH DAKOTA SATURDAY NIGHT...AND
THEN INTO WESTERN MINNESOTA SUNDAY NIGHT. FRIDAY NIGHT THROUGH
SATURDAY NIGHT...THE TRACK OF THE UPPER LOW/SURFACE LOW PUTS MOST OF
CENTRAL AND SOUTHERN NORTH DAKOTA IN THE WARM SECTOR. UNCERTAINTY
REMAINS ON HOW MUCH OF A DRY SLOT...IF ANY...WILL WORK ITS WAY INTO
SOUTHERN/CENTRAL NORTH DAKOTA. SEVERE WEATHER IS POSSIBLE SATURDAY
INTO SATURDAY NIGHT. DETAILS ON EXACTLY WHERE THIS WILL OCCUR STILL
IN QUESTION PER 12Z GFS AND 12Z ECMWF. WITH THE SURFACE LOW AND WARM
FRONTAL POSITION LOCATED OVER SOUTH CENTRAL NORTH DAKOTA SATURDAY
AFTERNOON...THE BEST INSTABILITY AND SHEAR RESIDES ALONG AND
NORTH...WHICH WOULD PLACE NORTHWEST/NORTH CENTRAL/AND THE JAMES
RIVER VALLEY IN A PRIME LOCATION. THE GFS PORTRAYS THIS MORE THAN
THE ECMWF. THE ECMWF KEEPS THE GREATEST INSTABILITY AND SHEAR MAINLY
OVER SOUTH CENTRAL NORTH DAKOTA AND THE JAMES RIVER VALLEY. THIS
WILL LIKELY CHANGE OVER THE COMING DAYS...SO WILL BE ABLE TO HONE IN
ON THIS MORE IN THE NEXT FEW DAYS. CAPE VALUES ARE FORECAST BETWEEN
1000-2000 J/KG WITH 0-6KM BULK SHEAR OF 35KT TO 45KT IN THE GREATEST
AREAS OF INSTABILITY ON BOTH MODELS. WILL CONTINUE TO CLOSELY
MONITOR.
MONDAY INTO TUESDAY...BOTH THE GFS AND ECMWF SHOW THE WEEKEND STORM
DEPARTING SUNDAY NIGHT LEAVING MONDAY/MONDAY NIGHT DRY WITH A
TRANSITORY 700MB-500MB RIDGE MIGRATING FROM SOUTHWEST TO NORTHEAST.
ANOTHER UPPER LOW IS FORECAST TO FOLLOW A SIMILAR PATH FOR TUESDAY
AND WEDNESDAY WITH POTENTIALLY ANOTHER WIDESPREAD PRECIPITATION
EVENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1256 AM CDT WED MAY 13 2015
AT MIDNIGHT CDT...A SURFACE LOW PRESSURE SYSTEM WAS CENTERED OVER
WYOMING...WITH A WARM FRONT EXTENDING EASTWARD FROM THE LOW ACROSS
SOUTH DAKOTA. THE SURFACE PRESSURE GRADIENT WAS INCREASING...AND
EXPECTING GUSTY EASTERLY WINDS THIS MORNING AT TAF SITES - WITH
STRONGEST WINDS ACROSS SOUTHERN TERMINALS OF KISN/KBIS/KJMS. SHORT
TERM MODELS INDICATE DEVELOPMENT AND EXPANSION OF MVFR
CIGS WITH RAIN SHOWERS AT KISN/KMOT/KDIK BETWEEN 06Z-09Z. LESS
CONFIDENCE ON MVFR CIGS AT KBIS/KJMS UNTIL AFT 09Z. WARM FRONT LIFTS
NORTHWARD INTO NORTH DAKOTA DAYTIME WEDNESDAY AND BECOMES ORIENTED
NORTHEAST-TO-SOUTHWEST ACROSS EASTERN/CENTRAL NORTH DAKOTA WITH A
FOCUS FOR MVFR CIGS AND RAIN SHOWERS MAINLY AFT 00Z THURSDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...NH
LONG TERM...KS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS NORMAN OK
412 PM CDT WED MAY 13 2015
.DISCUSSION...
PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH
CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA...
ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND
WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS
AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY
PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS
BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS.
OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM
WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE
MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD
AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE
OF THE HEAVY RECENT RAINFALL.
STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE
INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE
PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY
FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING
WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT
EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE
EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE
SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 60 80 65 79 / 80 20 30 40
HOBART OK 58 80 62 81 / 50 10 40 30
WICHITA FALLS TX 61 82 65 82 / 50 10 40 40
GAGE OK 55 83 60 82 / 60 10 30 20
PONCA CITY OK 58 80 65 80 / 90 30 20 30
DURANT OK 63 81 66 79 / 80 40 30 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR OKZ007-008-012-
013-017>020-022>048-050>052.
TX...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR TXZ083>090.
&&
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
247 PM PDT WED MAY 13 2015
UPDATED AVIATION DISCUSSION
.SHORT TERM...WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A DEEP
LONGWAVE TROUGH OVER THE NORTHEAST PACIFIC WATERS EXTENDING INLAND
THROUGH THE FAR WESTERN CONUS. EMBEDDED IN THIS LARGE TROUGH ARE
SEVERAL WELL- DEFINED SHORTWAVE TROUGHS FROM COASTAL CALIFORNIA
NORTH TROUGH EASTERN WASHINGTON. CLOSER TO HOME...WE`RE DEALING
WITH SHORTWAVE ENERGY MOVING SOUTH TO NORTH OVER NORTHERN
CALIFORNIA...AND THIS WILL COMBINE WITH SOME INSTABILITY OVER THE
FORECAST AREA TO GENERATE SHOWERS AND SOME THUNDERSTORMS THIS
AFTERNOON. LATEST HRRR GUIDANCE HAS HELPED US REFINE AREAS FOR
THUNDERSTORM POTENTIAL...AND WE HAVE SPREAD THE CHANCES ALL THE
WAY INTO THE UMPQUA BASIN LATE THIS AFTERNOON BASED ON THIS
OUTPUT. STORMS WILL TRACK SOUTH- SOUTHEAST TO NORTH-NORTHWEST SO
ANY SHOWERS AND STORMS OVER THE SISKIYOUS AND CASCADES HAVE THE
POTENTIAL TO MOVE OVER THE MEDFORD AREA THIS AFTERNOON/EVENING.
TONIGHT...SHORTWAVE ENERGY WILL BE OVERHEAD AND WILL MAINTAIN THE
CHANCE FOR SHOWERS FOR MOST OF THE CWA. WE HAVE DECIDED TO KEEP
THUNDERSTORMS OUT OF THE FORECAST OVERNIGHT BECAUSE IT DOES NOT
SEEM LIKE INSTABILITY ALOFT IS FAVORABLE ENOUGH TO SUPPORT
NOCTURNAL STORMS.
TOMORROW SHOULD BE THE BEST CHANCE FOR THUNDERSTORMS OVER A WIDE
AREA OF SOUTHERN OREGON AND NORTHERN CALIFORNIA. INSTABILITY
INCREASES SUBTLY THROUGH MUCH OF THE ATMOSPHERIC COLUMN TOMORROW AND
SHORTWAVE ENERGY WILL BE OF MODERATE STRENGTH. GFS40 850MB COMPUTED
LIFTED INDICES ARE ZERO OR SLIGHTLY NEGATIVE AND THIS SUPPORTS A
SLIGHT CHANCE OF THUNDERSTORMS. BULK SHEAR FROM 0-6KM IS HIGHER
TOMORROW SO THERE IS A BETTER CHANCE FOR A FEW STRONG STORMS.
ON FRIDAY...THE UPPER LOW THAT`S THE SOURCE OF ENERGY FOR OUR
SHOWERS WILL PUSH INTO NEVADA AND PRECIPITATION CHANCES WILL BE
FOCUSED EAST OF THE CASCADES. THE LOW PROGRESSION CONTINUES EASTWARD
AND BY SATURDAY THERE IS INCREASED STABILITY AND LITTLE TO NO
SHORTWAVE ACTIVITY...SO WE HAVE REMOVED RAIN CHANCES FOR A GOOD
PORTION OF THE FORECAST AREA. IN SHORT...SATURDAY SHOULD BE THE
DRIEST DAY OF THE WEEK.
.LONG TERM...SUNDAY MAY 17TH THROUGH WEDNESDAY MAY 20TH...NOT
MANY CHANGES MADE TO THE LONG TERM. MODELS ARE STILL IN GOOD
AGREEMENT ON A GENERAL LONG WAVE TROUGH PATTERN REMAINING OVER THE
AREA. THIS LENDS TO HIGH CONFIDENCE THAT UNSETTLED WEATHER WILL
CONTINUE THROUGH THE EXTENDED PERIOD. MODELS SHOW MARGINAL
INSTABILITY DURING THE AFTERNOONS AND EVENINGS THROUGH THIS TIME
FRAME AND IS ENOUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE CASCADES AND EAST SIDE. TEMPERATURES WILL
REMAIN WITHIN A FEW DEGREES OF NORMAL THROUGH THE EXTENDED AND DAY
TO DAY VARIABILITY WILL BE MINIMAL. MND
&&
.AVIATION...FOR THE 14/00Z TAF CYCLE...SHOWERS AND MOSTLY CLOUD TO
OVERCAST SKIES WILL CONTINUE THROUGH TOMORROW EVENING OVER MOST OF
AREA, WITH NEARLY ALL TERMINALS LIKELY TO SEE AT LEAST A SHOWER IN
THE VICINITY. CIGS ARE EXPECTED TO DROP AND REMAIN PRIMARILY MVFR
TONIGHT ALONG THE COAST AND IN THE UMPQUA BASIN...WITH LOCAL AREAS
OF IFR AND PARTIAL TERRAIN OBSCURATION. MVFR CIGS WILL DEVELOP IN
OTHER WEST SIDE VALLEYS BY THURSDAY MORNING. CIGS SHOULD LIFT TO VFR
BY THURSDAY AFTERNOON.
CASCADES AND EAST...MOSTLY VFR CIGS WITH AREAS OF TERRAIN
OBSCURATION AND LOCAL AREAS OF MVFR. POSSIBLE ISOLATED THUNDERSTORMS
THURSDAY AFTERNOON.
-MSC
&&
.MARINE...UPDATED 230 PM PDT WEDNESDAY, MAY 13, 2015...WINDS WILL
REMAIN WEAK TONIGHT AND PRIMARILY SOUTHERLY. SCATTERED LIGHT SHOWERS
WILL AFFECT THE WATERS THROUGH THURSDAY AFTERNOON AS AN UPPER LOW
CURRENTLY CENTERED ROUGHLY 400 MILES WEST OF VANCOUVER ISLAND TRACKS
SOUTH/SOUTHEASTWARD. NORTHWESTERLY SWELL ASSOCIATED WITH THIS SYSTEM
WILL CONTINUE BUILDING THIS EVENING INTO THURSDAY, CAUSING MODERATE
SEAS. NORTHERLY WINDS WILL INCREASE THURSDAY EVENING, BUT ARE
EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. WINDS WILL BE STRONGEST
SOUTH OF CAPE BLANCO. SEAS BEGIN DIMINISHING THURSDAY NIGHT, AND
WILL REMAIN RELATIVELY CALM THROUGH THE WEEKEND. WINDS WILL REMAIN
NORTHERLY TO NORTHWESTERLY AND MODERATE THROUGH THE WEEKEND. BOTH
13/12Z GFS AND EC SHOW SIMILAR LOW PRESSURE SYSTEMS THIS WEEKEND
FORMING FAR ENOUGH OFFSHORE TO KEEP WINDS BELOW ADVISORY CRITERIA.
-MSC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
NSK/MND/BPN/MSC
AREA FORECAST DISCUSSION...UPDATE
NWS PENDLETON OR
1053 AM PDT WED MAY 13 2015
UPDATED FOR MORNING UPDATE AND AVIATION DISCUSSION
.UPDATE...THE SNOW ACROSS THE BLUE MOUNTAINS THIS MORNING WAS
DECREASING AND THE WINTER WARNING WAS CANCELLED. HOWEVER A LARGE
AREA OF PCPN HAD DRIFTED WEST INTO THE COLUMBIA BASIN WHERE LIGHT TO
MODERATE RAIN IS PERSISTING. THIS AREA OF PCPN IS NOW LOCATED
BETWEEN YAKIMA AND PASCO AND SHOULD MOVE LITTLE AND POPS WERE
UPDATED TO REFLECT THIS TODAY. FURTHER SOUTH DAYTIME HEATING MAY
COMBINE WITH THE MOISTURE TO PRODUCE ISOLD TSRA THIS AFTERNOON AND
THE PRESENT SHORT TERM FORECAST APPEARS ON TRACK FOR NOW.
&&
.AVIATION...18Z TAFS...VFR CONDITIONS EXPECTED AT ALL TAF
SITES...EXCEPT FOR KYKM...KPSC...KALW AS THESE SITES MAY BE MVFR
OVER THE NEXT 6 HOURS AS THE AREA OF MODERATE RAIN PUSHES OFF TO THE
NORTHWEST. KYKM WILL SEE THE MOST RAINFALL OVER THE NEXT 6-9
HRS...WHILE KALW AND KPSC SHOULD ONLY SEE RAIN OVER THE NEXT 3 TO 6
HOURS. SPOT SHOWERS STILL POSSIBLE THIS AFTERNOON...DUE TO CLOUD
BREAKS AND A SIGNIFICANTLY MOIST LOW LEVEL. EXPECT SHOWERS TO ENTER
THE KRDM...KBDN AREA AFTER 0Z THURSDAY. THESE SHOWERS WILL LINGER
FOR 3-6 HOURS. WINDS WILL BE 5 TO 15 KTS MAINLY OUT OF THE
WEST...WITH GUSTS UP TO 25 KTS AT TIMES. WEBER
&&
.PREV DISCUSSION... /ISSUED 758 AM PDT WED MAY 13 2015/
UPDATE...THE LATEST RADAR WAS SHOWING A BLOB OF LIGHT TO MODERATE
RAIN OVER THE COLUMBIA BASIN AND HAVE INCREASED POPS OVER THIS
AREA THIS MORNING. MEANWHILE WEB CAMS WERE STILL SHOWING -SN ABOVE
4K IN THE BLUE MOUNTAINS AND ADJUSTED SNOW LEVELS SOME TO INDICATE
THIS. THE PCPN WAS A RESULT OF A STUBBORN LOW PRESSURE SYSTEM OVER
THE TWO STATE AREA WHICH WILL REMAIN STATIONARY OVER WA/OR AND THE
PCPN IS EXPECTED TO CONTINUE MAINLY NORTH OF THE STATE LINE TODAY.
HOWEVER RAP AROUND MOISTURE WILL PERSIST INTO MOSTLY NORTHERN
OREGON TODAY AND THE PRESENT SHORT TERM FORECAST APPEARS ON TRACK
FOR NOW.
PREV DISCUSSION... /ISSUED 300 AM PDT WED MAY 13 2015/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...AN UPPER LOW CONTINUES
TO ROTATE NORTHEAST ACROSS EASTERN OREGON EARLY THIS MORNING. THERE
IS AN AREA OF HEAVY PRECIP LOCATED TO THE NORTH AND NORTHWEST OF
THIS LOW. THUS HEAVY PRECIP HAS BEEN FALLING FROM NORTHERN GRANT
COUNTY INTO THE BLUE MOUNTAINS, GRANDE RONDE VALLEY, THE BLUE
MOUNTAIN FOOTHILLS, AND LOWER COLUMBIA BASIN EARLY THIS MORNING.
PRECIP AMOUNTS IN THE BLUES AND BLUE MTN FOOTHILLS HAVE BEEN
SUFFICIENT TO PROMPT THE ISSUANCE OF SMALL STREAM FLOOD ADVISORY FOR
THESE AREAS. ALSO SNOW LEVELS HAVE LOWERED IN THE BLUES TO NEAR 4500
FEET, LOCALLY TO 4000 FEET IN THE HEAVIEST PRECIP AREAS. COULD SEE 4
TO 8 INCHES OF SNOW ABOVE 4500 FEET AND HAVE ISSUED A WINTER STORM
WARNING FOR THE NORTHERN OREGON BLUE MOUNTAINS ZONE. THIS MAIN AREA
OF HEAVY PRECIP WILL GRADUALLY LIFT OFF TO THE NORTHWEST THIS
MORNING. THUS WILL KEEP POPS HIGH ACROSS OUR WASHINGTON ZONES
THROUGH THE MORNING. SHOULD SEE A GRADUAL END TO THE PRECIP ACROSS
NORTHEAST OREGON. CENTRAL OREGON WILL BE MOSTLY DRY THIS MORNING.
THE STEADY PRECIP WILL PERSIST OVER KITTITAS COUNTY AND PORTIONS OF
YAKIMA COUNTY INTO THE AFTERNOON. INSTABILITY LOOKS TO RATHER
LIMITED ACROSS OUR OREGON ZONES THIS AFTERNOON, BUT WILL CONTINUE TO
INDICATE ISOLATED TO SCATTERED SHOWERS. ALSO WILL LEAVE A SLIGHT
CHANCE MENTION OF THUNDERSTORMS FROM CENTRAL OREGON EAST TO GRANT
COUNTY AND NORTHEAST TO THE BLUE MOUNTAINS, GRANDE RONDE VALLEY AND
WALLOWA COUNTY. SHOWERS WILL DECREASE ACROSS MUCH OF THE AREA LATE
THIS EVENING AND OVERNIGHT, THOUGH ANOTHER WAVE ROTATING INTO THE
REGION LOOKS TO POTENTIALLY INCREASE SHOWER CHANCES OVER CENTRAL
OREGON LATE TONIGHT INTO THURSDAY MORNING. THIS SAME WAVE WILL
DESTABILIZE THE AIR MASS OVER THE REGION THURSDAY AFTERNOON AND
EVENING WITH VARYING CHANCES OF SHOWERS EXPECTED FOR MOST AREAS.
ALSO A FEW THUNDERSTORMS WILL BE POSSIBLE FOR MANY LOCATIONS. 90
LONG TERM...FRIDAY THROUGH WEDNESDAY...PATTERN WILL BE DOMINATED BY
GENERAL UPPER LEVEL TROUGHINESS THROUGH THE PERIOD. THERE WILL NOT
BE A MAJOR STORM SYSTEM...BUT IT APPEARS THAT THERE WILL BE
UNSETTLED WEATHER THROUGH THE MIDDLE OF NEXT WEEK. THE ATMOSPHERE
WILL BE MARGINALLY UNSTABLE EACH AFTERNOON...AND WITH SUFFICIENT
MOISTURE...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
DEVELOP. RIGHT NOW IT APPEARS THAT THE WETTEST DAYS COULD BE MONDAY
AND TUESDAY OF NEXT WEEK BUT THAT WILL CERTAINLY BE SUBJECT TO
CHANGE GIVEN THE WEAK UPPER LEVEL FORCING. THAT BEING SAID...DURING
THE NEXT SEVERAL DAYS SOME AREAS COULD SEE BENEFICIAL RAIN.
TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER BUT SHOULD BE NEAR
NORMAL FOR THIS TIME OF YEAR. 78
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 62 43 67 46 / 90 10 30 30
ALW 63 47 69 50 / 90 10 30 30
PSC 64 46 73 50 / 100 10 20 20
YKM 58 43 70 48 / 90 30 20 20
HRI 66 43 72 50 / 90 10 30 20
ELN 57 42 70 47 / 90 40 20 20
RDM 63 39 61 41 / 30 30 50 40
LGD 60 39 64 46 / 80 20 30 30
GCD 63 38 64 42 / 30 20 50 40
DLS 65 47 71 50 / 60 20 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
97/99/99
AREA FORECAST DISCUSSION
NWS PENDLETON OR
758 AM PDT WED MAY 13 2015
.UPDATE...THE LATEST RADAR WAS SHOWING A BLOB OF LIGHT TO MODERATE
RAIN OVER THE COLUMBIA BASIN AND HAVE INCREASED POPS OVER THIS
AREA THIS MORNING. MEANWHILE WEB CAMS WERE STILL SHOWING -SN ABOVE
4K IN THE BLUE MOUNTAINS AND ADJUSTED SNOW LEVELS SOME TO INDICATE
THIS. THE PCPN WAS A RESULT OF A STUBBORN LOW PRESSURE SYSTEM OVER
THE TWO STATE AREA WHICH WILL REMAIN STATIONARY OVER WA/OR AND THE
PCPN IS EXPECTED TO CONTINUE MAINLY NORTH OF THE STATE LINE TODAY.
HOWEVER RAP AROUND MOISTURE WILL PERSIST INTO MOSTLY NORTHERN
OREGON TODAY AND THE PRESENT SHORT TERM FORECAST APPEARS ON TRACK
FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 300 AM PDT WED MAY 13 2015/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...AN UPPER LOW CONTINUES
TO ROTATE NORTHEAST ACROSS EASTERN OREGON EARLY THIS MORNING. THERE
IS AN AREA OF HEAVY PRECIP LOCATED TO THE NORTH AND NORTHWEST OF
THIS LOW. THUS HEAVY PRECIP HAS BEEN FALLING FROM NORTHERN GRANT
COUNTY INTO THE BLUE MOUNTAINS, GRANDE RONDE VALLEY, THE BLUE
MOUNTAIN FOOTHILLS, AND LOWER COLUMBIA BASIN EARLY THIS MORNING.
PRECIP AMOUNTS IN THE BLUES AND BLUE MTN FOOTHILLS HAVE BEEN
SUFFICIENT TO PROMPT THE ISSUANCE OF SMALL STREAM FLOOD ADVISORY FOR
THESE AREAS. ALSO SNOW LEVELS HAVE LOWERED IN THE BLUES TO NEAR 4500
FEET, LOCALLY TO 4000 FEET IN THE HEAVIEST PRECIP AREAS. COULD SEE 4
TO 8 INCHES OF SNOW ABOVE 4500 FEET AND HAVE ISSUED A WINTER STORM
WARNING FOR THE NORTHERN OREGON BLUE MOUNTAINS ZONE. THIS MAIN AREA
OF HEAVY PRECIP WILL GRADUALLY LIFT OFF TO THE NORTHWEST THIS
MORNING. THUS WILL KEEP POPS HIGH ACROSS OUR WASHINGTON ZONES
THROUGH THE MORNING. SHOULD SEE A GRADUAL END TO THE PRECIP ACROSS
NORTHEAST OREGON. CENTRAL OREGON WILL BE MOSTLY DRY THIS MORNING.
THE STEADY PRECIP WILL PERSIST OVER KITTITAS COUNTY AND PORTIONS OF
YAKIMA COUNTY INTO THE AFTERNOON. INSTABILITY LOOKS TO RATHER
LIMITED ACROSS OUR OREGON ZONES THIS AFTERNOON, BUT WILL CONTINUE TO
INDICATE ISOLATED TO SCATTERED SHOWERS. ALSO WILL LEAVE A SLIGHT
CHANCE MENTION OF THUNDERSTORMS FROM CENTRAL OREGON EAST TO GRANT
COUNTY AND NORTHEAST TO THE BLUE MOUNTAINS, GRANDE RONDE VALLEY AND
WALLOWA COUNTY. SHOWERS WILL DECREASE ACROSS MUCH OF THE AREA LATE
THIS EVENING AND OVERNIGHT, THOUGH ANOTHER WAVE ROTATING INTO THE
REGION LOOKS TO POTENTIALLY INCREASE SHOWER CHANCES OVER CENTRAL
OREGON LATE TONIGHT INTO THURSDAY MORNING. THIS SAME WAVE WILL
DESTABILIZE THE AIR MASS OVER THE REGION THURSDAY AFTERNOON AND
EVENING WITH VARYING CHANCES OF SHOWERS EXPECTED FOR MOST AREAS.
ALSO A FEW THUNDERSTORMS WILL BE POSSIBLE FOR MANY LOCATIONS. 90
LONG TERM...FRIDAY THROUGH WEDNESDAY...PATTERN WILL BE DOMINATED BY
GENERAL UPPER LEVEL TROUGHINESS THROUGH THE PERIOD. THERE WILL NOT
BE A MAJOR STORM SYSTEM...BUT IT APPEARS THAT THERE WILL BE
UNSETTLED WEATHER THROUGH THE MIDDLE OF NEXT WEEK. THE ATMOSPHERE
WILL BE MARGINALLY UNSTABLE EACH AFTERNOON...AND WITH SUFFICIENT
MOISTURE...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
DEVELOP. RIGHT NOW IT APPEARS THAT THE WETTEST DAYS COULD BE MONDAY
AND TUESDAY OF NEXT WEEK BUT THAT WILL CERTAINLY BE SUBJECT TO
CHANGE GIVEN THE WEAK UPPER LEVEL FORCING. THAT BEING SAID...DURING
THE NEXT SEVERAL DAYS SOME AREAS COULD SEE BENEFICIAL RAIN.
TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER BUT SHOULD BE NEAR
NORMAL FOR THIS TIME OF YEAR. 78
AVIATION...12Z TAFS...MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH
THE FORECAST PERIOD. AN AREA OF MODERATE RAIN OVER THE BLUE MOUNTAIN
FOOTHILLS WILL ROTATE WWD TOWARD KYKM THROUGH THE DAY WITH
ASSOCIATED MVFR CIGS AND VSBYS. OTHERWISE EXPECT BKN-OVC CONDITIONS
AT AROUND 5000 FEET AGL. WINDS WILL BE WESTERLY AT 10-20 KT AND
GUSTY DIMINISHING TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 62 43 67 47 / 90 10 30 30
ALW 63 47 69 51 / 90 10 30 30
PSC 64 46 73 51 / 100 10 20 20
YKM 58 45 70 49 / 90 30 20 20
HRI 66 43 72 51 / 90 10 30 20
ELN 57 42 70 48 / 90 40 20 20
RDM 63 39 61 42 / 20 30 50 40
LGD 60 40 64 47 / 80 20 30 30
GCD 63 38 64 43 / 30 20 50 40
DLS 65 47 71 51 / 40 20 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WARNING UNTIL 11 AM PDT THIS MORNING FOR ORZ502.
WA...NONE.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
97/99/99
AREA FORECAST DISCUSSION
NWS PENDLETON OR
1030 PM PDT TUE MAY 12 2015
UPDATED AVIATION DISCUSSION
.SHORT TERM...TONIGHT AND WEDNESDAY...UPPER LEVEL LOW PRESSURE
SYSTEM CONTINUES TO IMPACT THE REGION. A SURGE OF SHORTWAVE ENERGY
WRAPPING AROUND THE LOW IS COMING UP OUT OF NORTHWEST NEVADA WHICH
IS ACTING TO ENHANCE CONVECTIVE SHOWERS OVER FAR EASTERN OREGON.
THIS SHORTWAVE WILL PIVOT INTO NORTHEAST OREGON OVERNIGHT AND THEN
INTO EASTERN WASHINGTON EARLY WEDNESDAY. THE SHOWERS BEING GENERATED
AHEAD OF THIS SHORTWAVE ARE EXPECTED TO CONTINUE TO ENHANCE AND
BECOME MORE CLUSTERED TOGETHER AS A PRECIPITATION SHIELD. THIS AREA
OF PRECIPITATION HAS THE POTENTIAL TO PRODUCE SOME SIGNIFICANT
AMOUNTS OF RAIN AS IT PASSES THROUGH THE FORECAST AREA OVERNIGHT AND
WEDNESDAY ON THE ORDER OF AROUND HALF AN INCH IN THE LOW ELEVATIONS
AND AN INCH OR MORE IN THE MOUNTAINS. FORECAST HAS BEEN UPDATED TO
INCREASE THE CHANCE OF PRECIPITATION AND AMOUNT OF PRECIPITATION
OVERNIGHT AND WEDNESDAY.
.AVIATION...06Z TAFS...MVFR CONDITIONS CAN BE EXPECTED OVER THE NEXT
6-12 HOURS...AS A DEFORMATION BAND IS EXPECTED TO SET UP OVER
NORTHERN OREGON AND SOUTHERN WASHINGTON DURING THIS PERIOD. THIS
COULD ALLOW FOR PERIODS OF MODERATE RAIN...WITH CIGS POSSIBLY
FALLING TO IFR CATEGORIES. WINDS WILL RANGE FROM 5 TO 15 KTS...WITH
GUSTS UP TO 25 KTS.
&&
.PREV DISCUSSION... /ISSUED 351 PM PDT TUE MAY 12 2015/
SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY NIGHT. AN INTENSE AND
STATIONARY LOW PRESSURE SYSTEM OVER THE PACNW WILL CONTINUE TO PUMP
MOISTURE INTO OUR AREA AND COMBINING THIS WITH DAYTIME HEATING WILL
PRODUCE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. THE TSRA
COULD BECOME STRONG AND PRODUCE GUSTY WINDS AND HAIL WITH THE BEST
CHANCES OF THIS OCCURRING OVER THE EASTERN ZONES THAT INCLUDES IN
AND AROUND THE BLUE/WALLOWA MOUNTAINS AS WELL AS GRANT COUNTY.
ELSEWHERE SHOWERS WILL CONTINUE DEVELOPING ACROSS THE REGION INTO
THIS EVENING. AS THE LOW DRIFTS INTO NE OREGON LATER TONIGHT
MOISTURE WILL RAP AROUND THIS SYSTEM AND INTO THE EASTERN PORTIONS
OF THE AREA AND MODERATE TO HEAVY RAINFALL IS POSSIBLE WITH UP TO AN
INCH IN SOME LOCATIONS. THE LOW AND THE BULK OF THE MOISTURE DRIFT
NORTH WEDNESDAY MORNING WITH DECREASING CHANCES OF PCPN EXPECTED BUT
THE CLOUDS AND SHOWERS WILL PERSIST INTO WEDNESDAY AFTERNOON. A WEAK
DISTURBANCE WILL NEAR CENTRAL OREGON WEDNESDAY AFTERNOON THAT COULD
PRODUCE AN ISOLD TSRA. OTHERWISE THE BEST CHANCES FOR PCPN SHOULD
OCCUR ALONG THE WA/OR CASCADES WEDNESDAY NIGHT AND THURSDAY.
BY THURSDAY ANOTHER LOW PRESSURE SYSTEM WILL TRACK TO OUR SOUTH BUT
SHOWERS FROM THIS SYSTEM WILL MOVE NORTH AND INTO MOST PORTIONS OF
OUR AREA THURSDAY NIGHT. AFTERNOON TEMPERATURES WILL REMAIN COOL
TOMORROW BEFORE WARMER TEMPERATURES CAN BE EXPECTED THURSDAY.
LONG TERM...FRIDAY THROUGH MONDAY NIGHT...MILD YET UNSETTLED
WEATHER CAN BE EXPECTED FOR THE EXTENDED. A LOW PRESSURE SYSTEM
CENTERED OVER CENTRAL NEVADA WILL CONTINUE TO SPIN UP MOISTURE AND
POSSIBLE THUNDERSTORMS TO THE AREA ON FRIDAY. THIS SYSTEM WILL EXIT
THE AREA FRIDAY NIGHT WITH ANOTHER LOW MOVING TOWARDS THE PACIFIC
COAST ON SATURDAY. THIS LOW IS CURRENTLY FORECAST TO TRACK SOUTH OF
THE CWA TOWARDS THE NORTHERN CALIFORNIA COAST THROUGH THE WEEKEND.
THIS WILL ALLOW FOR MORE MOISTURE AND INSTABILITY TO BE SPUN UP OVER
THE AREA...PROVIDING ANOTHER CHANCE FOR THUNDERSTORMS. THE LOW IS
EXPECTED TO SLOWLY MOVE INLAND AND BE CENTERED OVER THE CA/NV
BOARDER ON MONDAY NIGHT. OVERALL THE AIRMASS SHOULD BE FAIRLY WARM
OVER THE AREA...KEEPING THE TEMPERATURES NEAR TO ABOVE NORMAL.
REASONABLE CLOUD COVER CAN BE EXPECTED AT NIGHT AS WELL...ALLOWING
FOR MILD NIGHTTIME LOWS. WEBER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 46 62 45 64 / 100 80 10 30
ALW 48 63 46 69 / 100 90 10 30
PSC 52 64 46 70 / 100 90 10 20
YKM 50 59 43 70 / 90 90 40 20
HRI 50 64 44 70 / 100 90 10 30
ELN 47 57 41 70 / 90 90 40 20
RDM 35 60 36 59 / 50 20 30 50
LGD 43 60 41 64 / 100 70 20 30
GCD 39 62 39 65 / 90 20 20 50
DLS 49 65 46 71 / 50 50 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
91/91/91
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1235 AM CDT WED MAY 13 2015
.UPDATE...
ISSUED AT 925 PM CDT TUE MAY 12 2015
STILL A POSSIBILITY OF LLJ/WAA SHOWER/STORM DEVELOPMENT TONIGHT
ALONG THE NORTHERN CWA. THE HRRR MODEL WAS SHOWING SOME DEVELOPMENT
THROUGH THE NIGHT. UNR RADAR WAS ALSO SHOWING SOME SHOWERS MOVING
INTO WESTERN SD THIS EVENING. THUS...LEFT IN THE POPS ACROSS THE
NORTH THROUGH THE NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY AFTERNOON)
ISSUED AT 323 PM CDT TUE MAY 12 2015
MID LEVEL CLOUDS ARE OCCURRING ACROSS PARTS OF SOUTHWEST NORTH
DAKOTA AND NORTHWEST SOUTH DAKOTA IN RESPONSE TO A WEAK UPPER LEVEL
WAVE. THE LOWER LEVELS ARE PRETTY DRY...AND OBS ARE SHOWING CLOUD
BASES AROUND 7K-8K FT...SO EXPECT THAT VERY LITTLE PRECIP IS
REACHING THE GROUND. DID THROW SPRINKLES INTO THE FORECAST FOR GOOD
MEASURE HOWEVER. LATER TONIGHT...A 40+ KT LLJ DEVELOPS...AND THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE. STILL ON THE DRY
SIDE HOWEVER...SO NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION WITH
ANY SHOWERS OR STORMS.
WEDNESDAY...A MORE POTENT UPPER LEVEL TROUGH APPROACHES FROM THE
SOUTHWEST. AT THE SURFACE AN INVERTED TROUGH WILL EXTEND FROM
SOUTHWEST SOUTH DAKOTA THROUGH NORTH CENTRAL SOUTH DAKOTA. SURFACE
BASED CONVECTION MAY BE POSSIBLE ALONG THIS BOUNDARY LATE
WEDNESDAY AFTERNOON AS ML CAPE VALUES RISE TO AROUND 1000 J/KG.
0-6 KM SHEAR ISNT OVERLY IMPRESSIVE /AROUND 20 KTS/ AND LCLS ARE
FAIRLY HIGH...BUT CANT RULE OUT A FEW STRONGER PULSE STORMS WITH
LARGE HAIL. THE MAIN FORCING ASSOCIATED WITH THE UPPER TROUGH THEN
SPREADS OVER THE REGION LATE WEDNESDAY NIGHT THROUGH THURSDAY.
HIGH CHANCE TO LIKELY POPS ARE IN THE FORECAST FOR THIS TIME
PERIOD.
.LONG TERM...(THURSDAY EVENING THROUGH TUESDAY)
ISSUED AT 323 PM CDT TUE MAY 12 2015
EXTENDED PERIOD STILL APPEARS TO BE AN ACTIVE ONE WITH SEVERAL
CHANCES FOR RAIN. BEGINNING FRIDAY...FIRST SYSTEM IS ALREADY
APPROACHING THE NORTHERN PLAINS. DURING THE DAYTIME HOURS...MODELS
SUGGEST MAINLY WESTERN AND CENTRAL SD SEEING THE BEST CHANCES.
FRIDAY NIGHT LOOKS TO BE THE BEST CHANCE FOR WIDESPREAD
PRECIPITATION OVER THE FORECAST AREA. MODELS ARE ACTUALLY IN RATHER
GOOD AGREEMENT IN TIMING AND PLACEMENT/COVERAGE OF RAIN SO DID NOT
MAKE MANY CHANGES TO THE LIKELY SUPERBLEND POPS. SATURDAY AND
SATURDAY NIGHT COULD BE QUITE INTERESTING AS SOME BETTER INSTABILITY
AND SHEAR SPREAD NORTHWARD ACROSS THE AREA. MODELS ARE AGAIN IN
PRETTY DECENT AGREEMENT IN SHOWING SHORTWAVE ENERGY MOVING ACROSS
THE AREA WITH SHOWERS AND STORMS DEVELOPING DURING THE AFTERNOON AND
EVENING HOURS SATURDAY. LEFT THE HIGH POPS ALONE THAT SUPERBLEND
GAVE AS THIS LOOKS GOOD FOR NOW. IN REGARDS TO THIS STRONGER WEEKEND
SYSTEM...THERE IS STILL SOME DISAGREEMENT IN THE OVERALL EVOLUTION
AND MOVEMENT OF THE MAIN UPPER LOW HEADING INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1234 AM CDT WED MAY 13 2015
VFR CONDITIONS ARE EXPECTED FOR ALL LOCATIONS THROUGH TONIGHT AND
WEDNESDAY WITH MID AND HIGH LEVEL CLOUDS STREAMING OVER. THERE WILL
BE A FEW HIGH BASED SHOWERS/STORMS POSSIBLY AFFECTING THE LOCATIONS
THROUGH THE NIGHT. OTHERWISE...BREEZY/WINDY SOUTHEAST WINDS ARE
EXPECTED TO CONTINUE THROUGH TONIGHT AND WEDNESDAY. VERY STRONG
WINDS OFF THE SURFACE TO OVER 50 KNOTS WILL BRING SOME LOW LEVEL
WIND SHEAR TO ATY AND ABR TONIGHT. EXPECT SOUTH WINDS AT 15 TO 25
KNOTS WITH GUSTS TO 30 TO 35 KNOTS TO MIX OUT ON WEDNESDAY. ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS MAY DEVELOP BY WEDNESDAY EVENING
POSSIBLY AFFECTING ALL LOCATIONS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SERR
LONG TERM...TMT
AVIATION...TDK
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1101 PM CDT THU MAY 14 2015
.AVIATION...
SCATTERED THUNDERSTORMS MAY HAVE A DIRECT IMPACT ON KAMA AND KDHT FOR
THE NEXT COUPLE OF HOURS. OTHERWISE...SOUTH SOUTHEAST SURFACE WINDS
EXPECTED TO PREVAIL OVERNIGHT. STRATUS LAYER LOOKING MORE LIKELY TO
DEVELOP PRIOR TO SUNRISE...BUT WILL NOT CALL FOR CEILINGS WITH THIS
ISSUANCE. DEVELOPMENTS WILL BE MONITORED. SURFACE WINDS WILL GUST
TO AROUND 30 KT FOR MUCH OF THE DAY ON FRIDAY AS DRYLINE SETS UP WELL
EAST OF ALL TERMINALS. DRYLINE RETREATS FRIDAY EVENING WITH GOOD
PROSPECTS FOR SCATTERED THUNDERSTORMS AT ALL TERMINALS.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 637 PM CDT THU MAY 14 2015/
AVIATION...
SCATTERED THUNDERSTORMS EXPECTED THIS EVENING AND OVERNIGHT ACROSS
FORECAST AREA AS SHORTWAVE TROF MOVES IN FROM THE SOUTHWEST AND LOW-
LEVEL JET DEVELOPS. DEVELOPMENT OF THUNDERSTORMS WILL LIKELY BE
HAMPERED SOMEWHAT BY DEVELOPING STABLE LAYER ALOFT...SO WILL INCLUDE
ONLY VCTS REMARK AT THIS TIME. AMENDMENTS WILL BE ISSUED AS TIMING
AND LOCATION OF THUNDERSTORMS CAN BE REFINED. COULD SEE MVFR
CEILINGS DEVELOP TONIGHT...BUT CERTAINTY OF SUCH OCCURRENCE IS TOO
LOW AT THIS TIME TO INCLUDE IN FORECAST. SOUTHWEST SURFACE WINDS
EXPECTED TO GUST TO AROUND 30 KT DURING THE DAY ON FRIDAY.
COCKRELL
PREV DISCUSSION... /ISSUED 417 PM CDT THU MAY 14 2015/
DISCUSSION...
WATER VAPOR CHANNEL AND VISIBLE BOTH SHOW EXTENSIVE HIGH LEVEL
MOISTURE/CIRRUS STREAMING NORTHEASTWARD ACROSS NEW MEXICO INTO THE
SOUTHERN AND CENTRAL PLAINS AHEAD OF A DEEP WEST COAST MID-UPPER
LOW. CURRENT OBSERVATIONS SHOW SOUTHERLY SURFACE WINDS AND NEAR
NORMAL TEMPERATURES FOR MID MAY ACROSS OUR REGION. THE SHALLOW MOIST
LAYER EVIDENT IN 12Z KAMA AND KMAF SOUNDINGS HAS MIXED OUT SOME THIS
AFTERNOON WITH A SLIGHT DOWNWARD TREND IN SURFACE DEW POINTS NOTED
IN REGIONAL OBSERVATIONS. SLIGHT BACKING TO SURFACE WINDS AND UPSTREAM
DEEPER MOISTURE HAS KEPT SURFACE DEW POINTS FROM MIXING OUT FURTHER
AND SHORT TERM MODEL FORECAST SOUNDINGS SHOWS GRADUAL DEEPENING OF
LOW LEVEL MOISTURE THROUGH THE EVENING. MODEST MLCAPE IS PRESENT
ACROSS THE AREA BUT EFFECTIVE BULK SHEAR IS MARGINAL AT BEST FOR
STORM ORGANIZATION AND SEVERE WEATHER POTENTIAL. A FEW MARGINALLY
SEVERE THUNDERSTORMS ARE STILL POSSIBLE THIS EVENING. VIS SAT/RADAR
AND LIGHTNING OBS SHOW ISOLATED/SCATTERED CONVECTIVE DEVELOPMENT SO
FAR LIMITED TO SOUTHEAST AND CENTRAL NEW MEXICO AND SOUTHEAST
COLORADO. CU FIELD HAS EXPANDED FURTHER EAST BENEATH CIRRUS SHIELD
ACROSS EASTERN NEW MEXICO AND AS WEAK SHORTWAVE TROUGH APPROACHES
CONVECTION SHOULD EXPAND. CURRENT THINKING IN HOW THIS EVOLVE ALIGNS
WELL WITH WRF AND HRRR MODEL PROGNOSTICATIONS AND RESEMBLE OUTPUT
FROM THESE REASONABLY WELL.
A PATTERN SIMILAR TO WHAT HAS BEEN SEEN RECENTLY AND ONE THAT IS
GENERALLY RECOGNIZED FOR BRINGING OUR REGION HIGHER PROBABILITY
PRECIPITATION CHANCES CONTINUES THROUGH THE FORECAST PERIOD. AFTER
THE DEPARTING WAVE EARLY TOMORROW THE FOCUS SHIFTS TO A PERIOD OF
ASCENT WITH ANOTHER APPROACHING SHORTWAVE AND THIS WILL RESULT IN
ANOTHER FAIRLY HIGH CONFIDENCE ROUND OF PRECIPITATION FRIDAY EVENING
AND OVERNIGHT. MADE MINOR ADJUSTMENTS TO TIMING AND INCREASED BOTH
QPF AND PRECIPITATION PROBABILITIES. MODELS ARE NOT TOO DISSIMILAR
WITH TIMING OF WHAT COULD BE A FAIRLY EXPANSIVE AREA OF
RAIN/THUNDERSTORMS EXITING THE AREA SATURDAY MORNING AND HAVE KEPT
PRECIPITATION CHANCES ACROSS THE EASTERN PORTION OF THE AREA THEN. BY
AFTERNOON MODEL DIFFERENCES IN POSITION OF THE DRYLINE LEAD TO SOME
UNCERTAINTY WITH WHERE CONVECTION WILL REDEVELOP. THE CONSENSUS IS
THIS WILL OCCUR NEAR THE TEXAS/OKLAHOMA STATE LINE...OR SLIGHTLY
WEST. THUS...RETAINED SLIGHT/LOW CHANCE POPS ACROSS THE EASTERNMOST
COUNTIES SATURDAY AFTERNOON. BEHIND THE DRYLINE...DEEP MIXING INTO
FAIRLY STRONG MOMENTUM ALOFT COULD RESULT IN A PERIOD OF NEAR
ADVISORY CRITERIA WINDS ACROSS PORTIONS OF THE AREA.
QUITE WEATHER IS EXPECTED SUNDAY IN BETWEEN TWO WAVES IN A REGION OF
MEAN HEIGHT RISES DUE TO LOW AMPLITUDE RIDGING. YET ANOTHER SYSTEM
TAKES A SIMILAR TRACK AS THE LAST FEW DOWN THE WEST COAST AND INTO
THE DESERT SOUTHWEST BY LATE MONDAY. INCREASING LARGE SCALE ASCENT
AND DEEPENING MOISTURE (PWATS RISING TO WELL ABOVE CLIMATOLOGY)
SHOULD JUSTIFY FAIRLY HIGH PRECIPITATION PROBABILITIES FROM MONDAY
NIGHT THROUGH TUESDAY. THEREAFTER MEDIUM RANGE MODELS DIVERGE BUT THE
GENERAL SOUTHWESTERLY FLOW PATTERN WITHOUT ANY ANTECEDENT SIGNIFICANT
SOUTHEASTWARD PUSH OF LOW LEVEL MOISTURE NECESSITATES AT LEAST LOW
PRECIPITATION PROBABILITIES THROUGH MID WEEK.
BRB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/16
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
657 PM CDT THU MAY 14 2015
.UPDATE...
THE SEVERE THUNDERSTORM WATCH HAS BEEN EXPANDED TO COVER THE
ENTIRE FORECAST AREA THROUGH 11 PM. THE LATEST HRRR GRADUALLY
MORPHS THE CLUSTER OF TSTMS ACROSS THE WRN SPLNS INTO A SQUALL
LINE WHICH THEN MOVES EAST TONIGHT. WE HAVE ALSO INCREASE THE POPS
FOR MOST AREAS.
&&
.AVIATION...
-TSRA IS EXPECTED AT KLBB AND PVW THIS EVENING...THEN SEVERAL
HOURS LATER AT KCDS. SOME SEVERE WIND WINDS AND LARGE HAIL ARE
POSSIBLE. VFR CONDITIONS WILL RETURN LATE TONIGHT...ALTHOUGH
THERE IS A LOW POTENTIAL FOR LOW CEILINGS...ESPECIALLY AT KCDS. SW
BREEZES WILL INCREASE FRIDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 214 PM CDT THU MAY 14 2015/
SHORT TERM...
FORECAST THINKING CONTINUES ON TRACK WITH THAT PROVIDED IN THE NOON
UPDATE. CAPE VALUES HAVE INCREASED A FAIR BIT IN THE LATEST
MESOANALYSES PEAKING AT VALUES IN EXCESS OF 3KJ/KG PARTICULARLY
ACROSS OUR SOUTHERN COUNTIES. BULK SHEAR CONTINUES TO BE RUNNING
AROUND 35 KTS THOUGH ONE OF THE MORE REMARKABLE FIELDS IN THIS
MORNING/S RUNS IS THE HELICITY...MOST NOTABLE THE 0-1KM FIELDS WHICH
RAMP UP RAPIDLY THIS EVENING. THE ONE NEGATIVE...AND HISTORICALLY
THIS CAN BE A DEAL-BREAKER...IS THE PRESENCE OF A PERSISTENT CIRRUS
SHIELD. AS SUCH THE SEVERE THREAT IS CONDITIONAL ON INITIATION OF
DEEP CONVECTION. HOWEVER...IF THINGS DO BECOME ESTABLISHED...ALL
FORMS OF CONVECTIVE SEVERE WILL BE LIKELY. DATA SUGGESTS THAT THE
WINDS WILL RAPIDLY BACK AROUND 00Z WITH ATTENDANT LOW LEVEL MOISTURE
SURGE AND ENHANCE THE TORNADO THREAT. ASSUMING DEEP CONVECTION
OCCURS...WOULD LOOK FOR INITIAL ACTIVITY TO BE SOMEWHAT DISCRETE AND
EVOLVE TOWARD SOME SORT OF QLCS LATER THIS EVENING. AFTER THE
ACTIVITY WANES THIS EVENING...COULD SEE A BIT OF FOG TOWARD
MORNING ESPECIALLY ACROSS THE ROLLING PLAINS. WITH THAT OUT OF THE
WAY...WE SHOULD GET A RESPITE IN CONVECTION UNTIL LATE FRIDAY
AFTERNOON OR EVENING WITH ANOTHER SYSTEM MOVING ACROSS AS
DISCUSSED IN THE LONG TERM.
LONG TERM...
MODELS ARE CHANGING COURSE A LITTLE BIT WITH REGARDS TO FRIDAY
CONVECTION. THE UPPER LEVEL JET STREAK WILL COME OUT OF THE
SOUTHWESTERN US FARTHER SOUTH CLOSER TO WEST TEXAS. THIS WILL
LEAVE THE REGION IN DIVERGENCE FLOW ALOFT. OVERNIGHT CONVECTION
LOOKS MORE LIKELY FROM FRIDAY NIGHT THROUGH MUCH OF SATURDAY
MORNING. A PACIFIC COLD FRONT WILL EVENTUALLY OVERTAKE A
RETREATING DRYLINE FRIDAY NIGHT DEVELOPING CONVECTION INITIALLY IN
EASTERN NEW MEXICO. A LOW LEVEL JET RAMPING UP WILL SUSTAIN
CONVECTION IN MORE OR LESS OF A LINEAR FORM. THIS WILL BE COUPLED
WITH STRONG HEIGHT FALLS OVERNIGHT. STEEPER LAPSE RATES ENTERING
THE REGION BECAUSE OF COOLING ALOFT WILL ALLOW THE POSSIBILITY OF
SEVERE STORMS. THE PACIFIC COLD FRONT WILL THEN STALL OUT OVER THE
ROLLING PLAINS WITH STRONGER LOW LEVEL CONVERGENCE ON SATURDAY
AFTERNOON. THE UPPER LEVEL JET POSITION WILL FAVOR THE CENTRAL
PLAINS RATHER THAN THE SOUTHERN HIGH PLAINS. ALTHOUGH THE SURFACE
CONVERGENCE WILL FAVOR SOME INITIATION SATURDAY AFTERNOON OR
EVENING OVER THE ROLLING PLAINS.
SUNDAY WILL SEE A BREAK FROM THE CONVECTION CHANCES AS THE
LONGWAVE TROUGH EJECTS OUT INTO THE PLAINS AND MIDWEST. A CANADIAN
COLD FRONT ON MONDAY WILL ALLOW LOW LEVEL MOISTURE TO BE DRAWN
BACK INTO THE REGION. OUR UNSETTLED WEATHER PATTERN WILL CONTINUE
NEXT WEEK WITH WESTERN CONUS TROUGHING RAPIDLY DEVELOPING AGAIN
NEXT WEEK. AT THE MOMENT...MONDAY-TUESDAY IS THE AGREED UPON
TIME FRAME FOR BEST CONVECTION IN BOTH THE GFS AND ECMWF.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 55 77 53 74 / 30 10 50 0
TULIA 58 79 58 77 / 50 10 60 10
PLAINVIEW 59 79 59 77 / 60 10 60 10
LEVELLAND 59 80 59 78 / 70 10 60 0
LUBBOCK 60 81 61 80 / 70 10 60 10
DENVER CITY 59 81 58 78 / 30 10 60 0
BROWNFIELD 61 82 60 80 / 60 10 60 10
CHILDRESS 64 83 64 83 / 70 10 60 50
SPUR 63 82 63 83 / 70 10 60 20
ASPERMONT 66 83 66 85 / 70 20 60 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
637 PM CDT THU MAY 14 2015
.AVIATION...
SCATTERED THUNDERSTORMS EXPECTED THIS EVENING AND OVERNIGHT ACROSS
FORECAST AREA AS SHORTWAVE TROF MOVES IN FROM THE SOUTHWEST AND LOW-
LEVEL JET DEVELOPS. DEVELOPMENT OF THUNDERSTORMS WILL LIKELY BE
HAMPERED SOMEWHAT BY DEVELOPING STABLE LAYER ALOFT...SO WILL INCLUDE
ONLY VCTS REMARK AT THIS TIME. AMENDMENTS WILL BE ISSUED AS TIMING
AND LOCATION OF THUNDERSTORMS CAN BE REFINED. COULD SEE MVFR
CEILINGS DEVELOP TONIGHT...BUT CERTAINTY OF SUCH OCCURRENCE IS TOO
LOW AT THIS TIME TO INCLUDE IN FORECAST. SOUTHWEST SURFACE WINDS
EXPECTED TO GUST TO AROUND 30 KT DURING THE DAY ON FRIDAY.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 417 PM CDT THU MAY 14 2015/
DISCUSSION...
WATER VAPOR CHANNEL AND VISIBLE BOTH SHOW EXTENSIVE HIGH LEVEL
MOISTURE/CIRRUS STREAMING NORTHEASTWARD ACROSS NEW MEXICO INTO THE
SOUTHERN AND CENTRAL PLAINS AHEAD OF A DEEP WEST COAST MID-UPPER
LOW. CURRENT OBSERVATIONS SHOW SOUTHERLY SURFACE WINDS AND NEAR
NORMAL TEMPERATURES FOR MID MAY ACROSS OUR REGION. THE SHALLOW MOIST
LAYER EVIDENT IN 12Z KAMA AND KMAF SOUNDINGS HAS MIXED OUT SOME THIS
AFTERNOON WITH A SLIGHT DOWNWARD TREND IN SURFACE DEW POINTS NOTED
IN REGIONAL OBSERVATIONS. SLIGHT BACKING TO SURFACE WINDS AND UPSTREAM
DEEPER MOISTURE HAS KEPT SURFACE DEW POINTS FROM MIXING OUT FURTHER
AND SHORT TERM MODEL FORECAST SOUNDINGS SHOWS GRADUAL DEEPENING OF
LOW LEVEL MOISTURE THROUGH THE EVENING. MODEST MLCAPE IS PRESENT
ACROSS THE AREA BUT EFFECTIVE BULK SHEAR IS MARGINAL AT BEST FOR
STORM ORGANIZATION AND SEVERE WEATHER POTENTIAL. A FEW MARGINALLY
SEVERE THUNDERSTORMS ARE STILL POSSIBLE THIS EVENING. VIS SAT/RADAR
AND LIGHTNING OBS SHOW ISOLATED/SCATTERED CONVECTIVE DEVELOPMENT SO
FAR LIMITED TO SOUTHEAST AND CENTRAL NEW MEXICO AND SOUTHEAST
COLORADO. CU FIELD HAS EXPANDED FURTHER EAST BENEATH CIRRUS SHIELD
ACROSS EASTERN NEW MEXICO AND AS WEAK SHORTWAVE TROUGH APPROACHES
CONVECTION SHOULD EXPAND. CURRENT THINKING IN HOW THIS EVOLVE ALIGNS
WELL WITH WRF AND HRRR MODEL PROGNOSTICATIONS AND RESEMBLE OUTPUT
FROM THESE REASONABLY WELL.
A PATTERN SIMILAR TO WHAT HAS BEEN SEEN RECENTLY AND ONE THAT IS
GENERALLY RECOGNIZED FOR BRINGING OUR REGION HIGHER PROBABILITY
PRECIPITATION CHANCES CONTINUES THROUGH THE FORECAST PERIOD. AFTER
THE DEPARTING WAVE EARLY TOMORROW THE FOCUS SHIFTS TO A PERIOD OF
ASCENT WITH ANOTHER APPROACHING SHORTWAVE AND THIS WILL RESULT IN
ANOTHER FAIRLY HIGH CONFIDENCE ROUND OF PRECIPITATION FRIDAY EVENING
AND OVERNIGHT. MADE MINOR ADJUSTMENTS TO TIMING AND INCREASED BOTH
QPF AND PRECIPITATION PROBABILITIES. MODELS ARE NOT TOO DISSIMILAR
WITH TIMING OF WHAT COULD BE A FAIRLY EXPANSIVE AREA OF
RAIN/THUNDERSTORMS EXITING THE AREA SATURDAY MORNING AND HAVE KEPT
PRECIPITATION CHANCES ACROSS THE EASTERN PORTION OF THE AREA THEN. BY
AFTERNOON MODEL DIFFERENCES IN POSITION OF THE DRYLINE LEAD TO SOME
UNCERTAINTY WITH WHERE CONVECTION WILL REDEVELOP. THE CONSENSUS IS
THIS WILL OCCUR NEAR THE TEXAS/OKLAHOMA STATE LINE...OR SLIGHTLY
WEST. THUS...RETAINED SLIGHT/LOW CHANCE POPS ACROSS THE EASTERNMOST
COUNTIES SATURDAY AFTERNOON. BEHIND THE DRYLINE...DEEP MIXING INTO
FAIRLY STRONG MOMENTUM ALOFT COULD RESULT IN A PERIOD OF NEAR
ADVISORY CRITERIA WINDS ACROSS PORTIONS OF THE AREA.
QUITE WEATHER IS EXPECTED SUNDAY IN BETWEEN TWO WAVES IN A REGION OF
MEAN HEIGHT RISES DUE TO LOW AMPLITUDE RIDGING. YET ANOTHER SYSTEM
TAKES A SIMILAR TRACK AS THE LAST FEW DOWN THE WEST COAST AND INTO
THE DESERT SOUTHWEST BY LATE MONDAY. INCREASING LARGE SCALE ASCENT
AND DEEPENING MOISTURE (PWATS RISING TO WELL ABOVE CLIMATOLOGY)
SHOULD JUSTIFY FAIRLY HIGH PRECIPITATION PROBABILITIES FROM MONDAY
NIGHT THROUGH TUESDAY. THEREAFTER MEDIUM RANGE MODELS DIVERGE BUT THE
GENERAL SOUTHWESTERLY FLOW PATTERN WITHOUT ANY ANTECEDENT SIGNIFICANT
SOUTHEASTWARD PUSH OF LOW LEVEL MOISTURE NECESSITATES AT LEAST LOW
PRECIPITATION PROBABILITIES THROUGH MID WEEK.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 56 81 57 80 48 / 50 10 60 20 5
BEAVER OK 62 84 59 82 50 / 40 20 60 50 20
BOISE CITY OK 53 79 50 73 47 / 30 10 40 10 5
BORGER TX 60 83 59 79 53 / 50 10 60 20 5
BOYS RANCH TX 55 81 58 78 48 / 50 10 60 10 5
CANYON TX 56 80 57 79 49 / 50 10 60 10 5
CLARENDON TX 59 82 59 80 51 / 50 20 60 30 5
DALHART TX 52 80 54 75 46 / 40 10 50 10 5
GUYMON OK 57 82 56 79 49 / 40 10 50 20 10
HEREFORD TX 54 80 57 77 49 / 40 10 60 10 5
LIPSCOMB TX 62 83 61 81 53 / 50 20 60 50 20
PAMPA TX 59 80 57 78 49 / 50 10 60 30 5
SHAMROCK TX 63 82 63 81 53 / 50 20 60 50 20
WELLINGTON TX 64 84 63 83 54 / 50 20 60 60 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/16
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1158 AM CDT WED MAY 13 2015
.DISCUSSION...BASED ON LATEST RADAR TRENDS AND CONTINUED SLOW-
MOVING CONVECTION OVER MUCH OF SOUTH TEXAS...HAVE DECIDED TO
EXTEND THE FFA UNTIL 5 PM AND MATCH THE TORNADO WATCH. DEPENDING
ON CONVECTIVE TRENDS LATER THIS AFTERNOON...WATCH MAY BE CANCELLED
EARLY (AT LEAST IN SOME AREAS)...AND/OR EXTENDED FOR A FEW MORE
HOURS. MODEL DATA IS NOT SHOWING MUCH AFTER 02Z/03Z (THAT THAT ARE
SHOWING ANYTHING) SO WE WILL SEE WHAT HAPPENS.
&&
.PREV DISCUSSION... /ISSUED 1013 AM CDT WED MAY 13 2015/
DISCUSSION...TORNADO WATCH HAS BEEN ISSUED FOR PORTIONS OF OUR
AREA. UPDATED FORECAST FOR THIS...AND ADJUSTED SOME SHORT TERM
PARAMETERS AS WELL. HAVE NOT LOOKED AT TOO MUCH IN NEW MODEL DATA
AND FORECAST TRENDS...SO DID NOT CHANGE ANYTHING AFTER TODAY.
LOOKS THOUGH THAT THINGS WILL QUIET DOWN A BIT AFTER TODAY...BUT
STILL ENOUGH MOISTURE FOR CONVECTION THROUGH MOST OF THE FORECAST.
NO REAL CHANGES TO THE MARINE. PRODUCTS ARE OUT.
PREV DISCUSSION... /ISSUED 649 AM CDT WED MAY 13 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...CONVECTION WILL BE THE MAIN AVIATION CONCERN IN THE
IMMEDIATE TERM AT CRP TERMINAL...AND HAVE INCLUDED TSRA REMARKS.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS THE DAY
PROGRESSES AND HAVE VCTS/TEMPO TSRA AT ALL TERMINALS. IF
THUNDERSTORMS DIRECTLY IMPACT THE TERMINALS THEN REDUCED VSBYS AND
ERRATIC WINDS WILL BE POSSIBLE. OUTSIDE OF THUNDERSTORMS WINDS
WILL GENERALLY BE OUT OF THE EAST AND SOUTHEAST.
PREV DISCUSSION... /ISSUED 440 AM CDT WED MAY 13 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...THE FORECAST IS NOT EASY.
AS OF WRITING...A THIN AXIS CONTAINING DEEPEST MOISTURE WAS
LOCATED ALONG AND JUST OFFSHORE OF THE MIDDLE TEXAS COAST.
MODEST...BUT GRADUALLY STRENGTHENING...LOW LEVEL MOISTURE
ADVECTION WAS OCCURRING INTO THE AREA OF DEEPER MOISTURE.
THIS...IN ADDITION TO AN APPROACHING H5 VORT MAX...HAS LED TO
SIGNIFICANT SHOWERS AND THUNDERSTORMS PERSISTING OVER THE PAST
SEVERAL HOURS ACROSS THE NEARSHORE WATERS. AFTER COLLABORATION
WITH THE SATELLITE PRECIPITATION ANALYSIS BRANCH ABOUT WHERE HEAVY
RAINFALL POTENTIAL MAY OCCUR...HAVE DECIDED TO EXPAND FLASH FLOOD
WATCH INTO THE NORTHERN COASTAL BEND TO ACCOUNT FOR POTENTIAL OF
DEEPER MOISTURE AXIS SHIFTING NORTHWARD...WHICH COULD LEAD TO
HOURLY RAINFALL RATES OF 1 TO 3 INCHES. ELSEWHERE
INLAND...ISOLATED TO SCATTERED CONVECTION IS GRADUALLY DEVELOPING
IN RESPONSE TO A STRENGTHENING ESE 925MB LLJ. RAP MID LEVEL
HEIGHT ANALYSIS OVERLAID WITH WATER VAPOR IMAGERY INDICATES AN
APPROACHING MID LEVEL S/W TROUGH WHICH SHOULD AID IN CONVECTIVE
DEVELOPMENT ALONG THE RIO GRANDE BY SUNRISE. THE OVERALL FORECAST
FOR TODAY CALLS FOR CONVECTION ALONG THE COAST TO PERSIST AND
BUILD NORTHWARD THROUGH MID MORNING WITH ADDITIONAL CONVECTION
DEVELOPING/EXPANDING IN AREAL COVERAGE ALONG THE RIO GRANDE AND
BEGIN TO SHIFT NE. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE PRETTY
MUCH ANYWHERE TODAY AS PWATS REMAIN HIGH. A STRONG STORM WILL BE
POSSIBLE ACROSS THE REGION GIVEN EXPECTED MLCAPE VALUES AROUND
2000 J/KG AND SUFFICIENT BULK SHEAR VALUES /ESPECIALLY ACROSS NW
COUNTIES/. MAIN MID LEVEL TROUGH AXIS SWINGS THROUGH THE AREA BY
LATE TODAY RESULTING IN DRIER CONDITIONS TONIGHT. CAVEAT IS THAT A
A MINOR S/W TROUGH MAY PUSH ACROSS TONIGHT WHICH MAY LEAD TO
ADDITIONAL CONVECTIVE CHANCES...ESPECIALLY ACROSS SOUTHERN ZONES.
GUIDANCE INDICATES SOME DRIER AIR AT H85 BUILDING INTO THE REGION
ON THURSDAY RESULTING IN LOWER PRECIP CHANCES.
WILL ALLOW RIP CURRENT RISK TO EXPIRE AT 6 AM. A MODERATE RISK OF
RIP CURRENTS WILL EXIST TODAY AND MAY FLIRT WITH THE HIGH RISK
THRESHOLD AGAIN ON THURSDAY.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...AN UPPER LEVEL
DISTURBANCE WILL MOVE OUT OF MEXICO THURSDAY NIGHT INTO FRIDAY.
THIS WILL LEAD TO CONTINUED CHANCES OF SHOWERS AND STORMS OVER THE
WEST THURSDAY NIGHT...SHIFTING TO THE NORTHERN SECTIONS ON FRIDAY.
RAIN CHANCES MAY TEMPORARILY LOWER ON SATURDAY THE SHORTWAVE
TROUGH PASSES OFF TO THE NORTHEAST. WILL KEEP SOME LOW END 20 POPS
THOUGH WITH LINGERING MOISTURE ACROSS SOUTH TEXAS. ACTIVE WEATHER
PATTERN APPEARS TO RETURN BEGINNING SUNDAY THROUGH THE FIRST PART
OF NEXT WEEK. SOUTHWEST FLOW ALOFT WITH OCCASIONAL UPPER
DISTURBANCES WILL TRAVERSE THE REGION DURING THIS TIME. SUPERBLEND
POPS GENERALLY RANGE FROM 30 TO 50 PERCENT...AND WILL KEEP
OFFICIAL FORECAST SIMILAR TO SUPERBLEND NUMBERS. TEMPERATURES IN
THE 80S WILL BE COMMON THROUGH THE PERIOD...WITH LOWER 90S OVER
THE WESTERN ZONES FRIDAY THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 74 86 75 84 / 60 30 30 20 30
VICTORIA 81 72 88 73 83 / 70 40 30 20 40
LAREDO 85 72 91 73 90 / 60 20 20 30 30
ALICE 85 72 89 73 86 / 60 20 30 20 30
ROCKPORT 83 76 85 76 80 / 60 30 20 20 30
COTULLA 82 70 89 71 87 / 70 20 20 40 30
KINGSVILLE 86 74 88 75 86 / 60 30 30 20 30
NAVY CORPUS 83 75 84 76 81 / 60 30 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 5 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...
JIM WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...
NUECES...REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...NONE.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1013 AM CDT WED MAY 13 2015
.DISCUSSION...TORNADO WATCH HAS BEEN ISSUED FOR PORTIONS OF OUR
AREA. UPDATED FORECAST FOR THIS...AND ADJUSTED SOME SHORT-TERM
PARAMETERS AS WELL. HAVE NOT LOOKED AT TOO MUCH IN NEW MODEL DATA
AND FORECAST TRENDS...SO DID NOT CHANGE ANYTHING AFTER TODAY.
LOOKS THOUGH THAT THINGS WILL QUIET DOWN A BIT AFTER TODAY...BUT
STILL ENOUGH MOISTURE FOR CONVECTION THROUGH MOST OF THE FORECAST.
NO REAL CHANGES TO THE MARINE. PRODUCTS ARE OUT.
&&
.PREV DISCUSSION... /ISSUED 649 AM CDT WED MAY 13 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...CONVECTION WILL BE THE MAIN AVIATION CONCERN IN THE
IMMEDIATE TERM AT CRP TERMINAL...AND HAVE INCLUDED TSRA REMARKS.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS THE DAY
PROGRESSES AND HAVE VCTS/TEMPO TSRA AT ALL TERMINALS. IF
THUNDERSTORMS DIRECTLY IMPACT THE TERMINALS THEN REDUCED VSBYS AND
ERRATIC WINDS WILL BE POSSIBLE. OUTSIDE OF THUNDERSTORMS WINDS
WILL GENERALLY BE OUT OF THE EAST AND SOUTHEAST.
PREV DISCUSSION... /ISSUED 440 AM CDT WED MAY 13 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...THE FORECAST IS NOT EASY.
AS OF WRITING...A THIN AXIS CONTAINING DEEPEST MOISTURE WAS
LOCATED ALONG AND JUST OFFSHORE OF THE MIDDLE TEXAS COAST.
MODEST...BUT GRADUALLY STRENGTHENING...LOW LEVEL MOISTURE
ADVECTION WAS OCCURRING INTO THE AREA OF DEEPER MOISTURE.
THIS...IN ADDITION TO AN APPROACHING H5 VORT MAX...HAS LED TO
SIGNIFICANT SHOWERS AND THUNDERSTORMS PERSISTING OVER THE PAST
SEVERAL HOURS ACROSS THE NEARSHORE WATERS. AFTER COLLABORATION
WITH THE SATELLITE PRECIPITATION ANALYSIS BRANCH ABOUT WHERE HEAVY
RAINFALL POTENTIAL MAY OCCUR...HAVE DECIDED TO EXPAND FLASH FLOOD
WATCH INTO THE NORTHERN COASTAL BEND TO ACCOUNT FOR POTENTIAL OF
DEEPER MOISTURE AXIS SHIFTING NORTHWARD...WHICH COULD LEAD TO
HOURLY RAINFALL RATES OF 1 TO 3 INCHES. ELSEWHERE
INLAND...ISOLATED TO SCATTERED CONVECTION IS GRADUALLY DEVELOPING
IN RESPONSE TO A STRENGTHENING ESE 925MB LLJ. RAP MID LEVEL
HEIGHT ANALYSIS OVERLAID WITH WATER VAPOR IMAGERY INDICATES AN
APPROACHING MID LEVEL S/W TROUGH WHICH SHOULD AID IN CONVECTIVE
DEVELOPMENT ALONG THE RIO GRANDE BY SUNRISE. THE OVERALL FORECAST
FOR TODAY CALLS FOR CONVECTION ALONG THE COAST TO PERSIST AND
BUILD NORTHWARD THROUGH MID MORNING WITH ADDITIONAL CONVECTION
DEVELOPING/EXPANDING IN AREAL COVERAGE ALONG THE RIO GRANDE AND
BEGIN TO SHIFT NE. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE PRETTY
MUCH ANYWHERE TODAY AS PWATS REMAIN HIGH. A STRONG STORM WILL BE
POSSIBLE ACROSS THE REGION GIVEN EXPECTED MLCAPE VALUES AROUND
2000 J/KG AND SUFFICIENT BULK SHEAR VALUES /ESPECIALLY ACROSS NW
COUNTIES/. MAIN MID LEVEL TROUGH AXIS SWINGS THROUGH THE AREA BY
LATE TODAY RESULTING IN DRIER CONDITIONS TONIGHT. CAVEAT IS THAT A
A MINOR S/W TROUGH MAY PUSH ACROSS TONIGHT WHICH MAY LEAD TO
ADDITIONAL CONVECTIVE CHANCES...ESPECIALLY ACROSS SOUTHERN ZONES.
GUIDANCE INDICATES SOME DRIER AIR AT H85 BUILDING INTO THE REGION
ON THURSDAY RESULTING IN LOWER PRECIP CHANCES.
WILL ALLOW RIP CURRENT RISK TO EXPIRE AT 6 AM. A MODERATE RISK OF
RIP CURRENTS WILL EXIST TODAY AND MAY FLIRT WITH THE HIGH RISK
THRESHOLD AGAIN ON THURSDAY.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...AN UPPER LEVEL
DISTURBANCE WILL MOVE OUT OF MEXICO THURSDAY NIGHT INTO FRIDAY.
THIS WILL LEAD TO CONTINUED CHANCES OF SHOWERS AND STORMS OVER THE
WEST THURSDAY NIGHT...SHIFTING TO THE NORTHERN SECTIONS ON FRIDAY.
RAIN CHANCES MAY TEMPORARILY LOWER ON SATURDAY THE SHORTWAVE
TROUGH PASSES OFF TO THE NORTHEAST. WILL KEEP SOME LOW END 20 POPS
THOUGH WITH LINGERING MOISTURE ACROSS SOUTH TEXAS. ACTIVE WEATHER
PATTERN APPEARS TO RETURN BEGINNING SUNDAY THROUGH THE FIRST PART
OF NEXT WEEK. SOUTHWEST FLOW ALOFT WITH OCCASIONAL UPPER
DISTURBANCES WILL TRAVERSE THE REGION DURING THIS TIME. SUPERBLEND
POPS GENERALLY RANGE FROM 30 TO 50 PERCENT...AND WILL KEEP
OFFICIAL FORECAST SIMILAR TO SUPERBLEND NUMBERS. TEMPERATURES IN
THE 80S WILL BE COMMON THROUGH THE PERIOD...WITH LOWER 90S OVER
THE WESTERN ZONES FRIDAY THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 74 86 75 84 / 60 30 30 20 30
VICTORIA 81 72 88 73 83 / 70 40 30 20 40
LAREDO 85 72 91 73 90 / 60 20 20 30 30
ALICE 85 72 89 73 86 / 60 20 30 20 30
ROCKPORT 83 76 85 76 80 / 60 30 20 20 30
COTULLA 82 70 89 71 87 / 70 20 20 40 30
KINGSVILLE 86 74 88 75 86 / 60 30 30 20 30
NAVY CORPUS 83 75 84 76 81 / 60 30 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 3 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...
JIM WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...
NUECES...REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...NONE.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
649 AM CDT WED MAY 13 2015
.DISCUSSION...UPDATED FOR 12Z AVIATION.
&&
.AVIATION...CONVECTION WILL BE THE MAIN AVIATION CONCERN IN THE
IMMEDIATE TERM AT CRP TERMINAL...AND HAVE INCLUDED TSRA REMARKS.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS THE DAY
PROGRESSES AND HAVE VCTS/TEMPO TSRA AT ALL TERMINALS. IF
THUNDERSTORMS DIRECTLY IMPACT THE TERMINALS THEN REDUCED VSBYS AND
ERRATIC WINDS WILL BE POSSIBLE. OUTSIDE OF THUNDERSTORMS WINDS
WILL GENERALLY BE OUT OF THE EAST AND SOUTHEAST.
&&
.PREV DISCUSSION... /ISSUED 440 AM CDT WED MAY 13 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...THE FORECAST IS NOT EASY.
AS OF WRITING...A THIN AXIS CONTAINING DEEPEST MOISTURE WAS
LOCATED ALONG AND JUST OFFSHORE OF THE MIDDLE TEXAS COAST.
MODEST...BUT GRADUALLY STRENGTHENING...LOW LEVEL MOISTURE
ADVECTION WAS OCCURRING INTO THE AREA OF DEEPER MOISTURE.
THIS...IN ADDITION TO AN APPROACHING H5 VORT MAX...HAS LED TO
SIGNIFICANT SHOWERS AND THUNDERSTORMS PERSISTING OVER THE PAST
SEVERAL HOURS ACROSS THE NEARSHORE WATERS. AFTER COLLABORATION
WITH THE SATELLITE PRECIPITATION ANALYSIS BRANCH ABOUT WHERE HEAVY
RAINFALL POTENTIAL MAY OCCUR...HAVE DECIDED TO EXPAND FLASH FLOOD
WATCH INTO THE NORTHERN COASTAL BEND TO ACCOUNT FOR POTENTIAL OF
DEEPER MOISTURE AXIS SHIFTING NORTHWARD...WHICH COULD LEAD TO
HOURLY RAINFALL RATES OF 1 TO 3 INCHES. ELSEWHERE
INLAND...ISOLATED TO SCATTERED CONVECTION IS GRADUALLY DEVELOPING
IN RESPONSE TO A STRENGTHENING ESE 925MB LLJ. RAP MID LEVEL
HEIGHT ANALYSIS OVERLAID WITH WATER VAPOR IMAGERY INDICATES AN
APPROACHING MID LEVEL S/W TROUGH WHICH SHOULD AID IN CONVECTIVE
DEVELOPMENT ALONG THE RIO GRANDE BY SUNRISE. THE OVERALL FORECAST
FOR TODAY CALLS FOR CONVECTION ALONG THE COAST TO PERSIST AND
BUILD NORTHWARD THROUGH MID MORNING WITH ADDITIONAL CONVECTION
DEVELOPING/EXPANDING IN AREAL COVERAGE ALONG THE RIO GRANDE AND
BEGIN TO SHIFT NE. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE PRETTY
MUCH ANYWHERE TODAY AS PWATS REMAIN HIGH. A STRONG STORM WILL BE
POSSIBLE ACROSS THE REGION GIVEN EXPECTED MLCAPE VALUES AROUND
2000 J/KG AND SUFFICIENT BULK SHEAR VALUES /ESPECIALLY ACROSS NW
COUNTIES/. MAIN MID LEVEL TROUGH AXIS SWINGS THROUGH THE AREA BY
LATE TODAY RESULTING IN DRIER CONDITIONS TONIGHT. CAVEAT IS THAT A
A MINOR S/W TROUGH MAY PUSH ACROSS TONIGHT WHICH MAY LEAD TO
ADDITIONAL CONVECTIVE CHANCES...ESPECIALLY ACROSS SOUTHERN ZONES.
GUIDANCE INDICATES SOME DRIER AIR AT H85 BUILDING INTO THE REGION
ON THURSDAY RESULTING IN LOWER PRECIP CHANCES.
WILL ALLOW RIP CURRENT RISK TO EXPIRE AT 6 AM. A MODERATE RISK OF
RIP CURRENTS WILL EXIST TODAY AND MAY FLIRT WITH THE HIGH RISK
THRESHOLD AGAIN ON THURSDAY.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...AN UPPER LEVEL
DISTURBANCE WILL MOVE OUT OF MEXICO THURSDAY NIGHT INTO FRIDAY.
THIS WILL LEAD TO CONTINUED CHANCES OF SHOWERS AND STORMS OVER THE
WEST THURSDAY NIGHT...SHIFTING TO THE NORTHERN SECTIONS ON FRIDAY.
RAIN CHANCES MAY TEMPORARILY LOWER ON SATURDAY THE SHORTWAVE
TROUGH PASSES OFF TO THE NORTHEAST. WILL KEEP SOME LOW END 20 POPS
THOUGH WITH LINGERING MOISTURE ACROSS SOUTH TEXAS. ACTIVE WEATHER
PATTERN APPEARS TO RETURN BEGINNING SUNDAY THROUGH THE FIRST PART
OF NEXT WEEK. SOUTHWEST FLOW ALOFT WITH OCCASIONAL UPPER
DISTURBANCES WILL TRAVERSE THE REGION DURING THIS TIME. SUPERBLEND
POPS GENERALLY RANGE FROM 30 TO 50 PERCENT...AND WILL KEEP
OFFICIAL FORECAST SIMILAR TO SUPERBLEND NUMBERS. TEMPERATURES IN
THE 80S WILL BE COMMON THROUGH THE PERIOD...WITH LOWER 90S OVER
THE WESTERN ZONES FRIDAY THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 74 86 75 84 / 60 30 30 20 30
VICTORIA 81 72 88 73 83 / 60 40 30 20 40
LAREDO 85 72 91 73 90 / 60 20 20 30 30
ALICE 85 72 89 73 86 / 50 20 30 20 30
ROCKPORT 83 76 85 76 80 / 60 30 20 20 30
COTULLA 82 70 89 71 87 / 70 20 20 40 30
KINGSVILLE 86 74 88 75 86 / 60 30 30 20 30
NAVY CORPUS 83 75 84 76 81 / 60 30 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 3 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...
JIM WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...
NUECES...REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...NONE.
&&
$$
TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
440 AM CDT WED MAY 13 2015
.SHORT TERM (TODAY THROUGH THURSDAY)...THE FORECAST IS NOT EASY.
AS OF WRITING...A THIN AXIS CONTAINING DEEPEST MOISTURE WAS
LOCATED ALONG AND JUST OFFSHORE OF THE MIDDLE TEXAS COAST.
MODEST...BUT GRADUALLY STRENGTHENING...LOW LEVEL MOISTURE
ADVECTION WAS OCCURRING INTO THE AREA OF DEEPER MOISTURE.
THIS...IN ADDITION TO AN APPROACHING H5 VORT MAX...HAS LED TO
SIGNIFICANT SHOWERS AND THUNDERSTORMS PERSISTING OVER THE PAST
SEVERAL HOURS ACROSS THE NEARSHORE WATERS. AFTER COLLABORATION
WITH THE SATELLITE PRECIPITATION ANALYSIS BRANCH ABOUT WHERE HEAVY
RAINFALL POTENTIAL MAY OCCUR...HAVE DECIDED TO EXPAND FLASH FLOOD
WATCH INTO THE NORTHERN COASTAL BEND TO ACCOUNT FOR POTENTIAL OF
DEEPER MOISTURE AXIS SHIFTING NORTHWARD...WHICH COULD LEAD TO
HOURLY RAINFALL RATES OF 1 TO 3 INCHES. ELSEWHERE
INLAND...ISOLATED TO SCATTERED CONVECTION IS GRADUALLY DEVELOPING
IN RESPONSE TO A STRENGTHENING ESE 925MB LLJ. RAP MID LEVEL
HEIGHT ANALYSIS OVERLAID WITH WATER VAPOR IMAGERY INDICATES AN
APPROACHING MID LEVEL S/W TROUGH WHICH SHOULD AID IN CONVECTIVE
DEVELOPMENT ALONG THE RIO GRANDE BY SUNRISE. THE OVERALL FORECAST
FOR TODAY CALLS FOR CONVECTION ALONG THE COAST TO PERSIST AND
BUILD NORTHWARD THROUGH MID MORNING WITH ADDITIONAL CONVECTION
DEVELOPING/EXPANDING IN AREAL COVERAGE ALONG THE RIO GRANDE AND
BEGIN TO SHIFT NE. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE PRETTY
MUCH ANYWHERE TODAY AS PWATS REMAIN HIGH. A STRONG STORM WILL BE
POSSIBLE ACROSS THE REGION GIVEN EXPECTED MLCAPE VALUES AROUND
2000 J/KG AND SUFFICIENT BULK SHEAR VALUES /ESPECIALLY ACROSS NW
COUNTIES/. MAIN MID LEVEL TROUGH AXIS SWINGS THROUGH THE AREA BY
LATE TODAY RESULTING IN DRIER CONDITIONS TONIGHT. CAVEAT IS THAT A
A MINOR S/W TROUGH MAY PUSH ACROSS TONIGHT WHICH MAY LEAD TO
ADDITIONAL CONVECTIVE CHANCES...ESPECIALLY ACROSS SOUTHERN ZONES.
GUIDANCE INDICATES SOME DRIER AIR AT H85 BUILDING INTO THE REGION
ON THURSDAY RESULTING IN LOWER PRECIP CHANCES.
WILL ALLOW RIP CURRENT RISK TO EXPIRE AT 6 AM. A MODERATE RISK OF
RIP CURRENTS WILL EXIST TODAY AND MAY FLIRT WITH THE HIGH RISK
THRESHOLD AGAIN ON THURSDAY.
&&
.LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...AN UPPER LEVEL
DISTURBANCE WILL MOVE OUT OF MEXICO THURSDAY NIGHT INTO FRIDAY.
THIS WILL LEAD TO CONTINUED CHANCES OF SHOWERS AND STORMS OVER THE
WEST THURSDAY NIGHT...SHIFTING TO THE NORTHERN SECTIONS ON FRIDAY.
RAIN CHANCES MAY TEMPORARILY LOWER ON SATURDAY THE SHORTWAVE
TROUGH PASSES OFF TO THE NORTHEAST. WILL KEEP SOME LOW END 20 POPS
THOUGH WITH LINGERING MOISTURE ACROSS SOUTH TEXAS. ACTIVE WEATHER
PATTERN APPEARS TO RETURN BEGINNING SUNDAY THROUGH THE FIRST PART
OF NEXT WEEK. SOUTHWEST FLOW ALOFT WITH OCCASIONAL UPPER
DISTURBANCES WILL TRAVERSE THE REGION DURING THIS TIME. SUPERBLEND
POPS GENERALLY RANGE FROM 30 TO 50 PERCENT...AND WILL KEEP
OFFICIAL FORECAST SIMILAR TO SUPERBLEND NUMBERS. TEMPERATURES IN
THE 80S WILL BE COMMON THROUGH THE PERIOD...WITH LOWER 90S OVER
THE WESTERN ZONES FRIDAY THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 74 86 75 84 / 50 30 30 20 30
VICTORIA 81 72 88 73 83 / 60 40 30 20 40
LAREDO 85 72 91 73 90 / 60 20 20 30 30
ALICE 85 72 89 73 86 / 50 20 30 20 30
ROCKPORT 83 76 85 76 80 / 50 30 20 20 30
COTULLA 82 70 89 71 87 / 70 20 20 40 30
KINGSVILLE 86 74 88 75 86 / 50 30 30 20 30
NAVY CORPUS 83 75 84 76 81 / 50 30 20 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 3 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...
JIM WELLS...LA SALLE...LIVE OAK...MCMULLEN...REFUGIO...
VICTORIA...WEBB.
HIGH RIP CURRENT RISK UNTIL 6 AM CDT EARLY THIS MORNING FOR THE
FOLLOWING ZONES: ARANSAS...CALHOUN...KLEBERG...NUECES.
GM...NONE.
&&
$$
RH/79...SHORT TERM
TB/78...LONG TERM
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
244 AM CDT WED MAY 13 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...IR SATL IMAGERY INDICATES PLENTY OF MID AND HIGH LEVEL
CLD COVER ADVECTING FROM SW TO NE OVER DEEP SOUTH TEXAS WITH A
PRETTY LARGE CONV COMPLEX BUILDING WEST TOWARDS THE COASTAL BEND
AREA. KBRO RADAR SHOWS QUIET CONDITIONS OVER THE INLAND AREAS OF
DEEP SOUTH TX AND FURTHER WEST AND SOUTH OF THE RIO GRANDE. IF THE
CONV COMPLEX BUILDING WEST TOWARDS THE COASTAL BEND MAINTAINS IT
SPEED AND CURRENT LEVEL OF ORGANIZATION IT SHOULD NOT HAVE ANY
MAJOR IMPACT ON THE RGV AIRPORTS OVER THE NEXT SEVERAL HOURS.
THE LATEST HRRR GUIDANCE SWINGS A COUPLE A ROUNDS OF CONV THROUGH
THE NORTHERN AND WESTERN PORTIONS OF THE BRO CWA LATER THIS
MORNING INTO THIS AFTERNOON. HOWEVER THE MODEL GUIDANCE KEEPS MOST
OF THIS CONV CLEAR OF RGV AIRPORTS THROUGHOUT THE BULK OF THE
CURRENT TAF FORECAST PERIOD. THE MOST RECENT SURFACE OBS SHOW THAT
SOME MVFR CEILINGS ARE MOVING IN OVER THE RGV EARLY THIS MORNING.
EXPECT THE CEILINGS TO THEN TREND MORE TOWARDS VFR LEVELS LATER
TODAY WITH SOME POSSIBLE BRIEF REDUCTIONS TO IFR/MVFR CONDITIONS
IF SOME OF THE ANTICIPATED CONV LATER TODAY MOVES OVER THE RGV
AIRPORTS.
&&
.PREV DISCUSSION... /ISSUED 651 PM CDT TUE MAY 12 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...VISIBLE SATELLITE IMAGERY SHOWS LOW CLOUDINESS
CURRENTLY AFFECTING THE AERODROMES WITH SIGNIFICANT CIRRUS FROM
CONVECTION IN NEIGHBORING MEXICO APPROACHING DEEP SOUTH TEXAS AND
THE RIO GRANDE VALLEY FROM THE SOUTHWEST. LOCAL RADAR IS FREE OF
PRECIPITATION ECHOES...AND IN THE WAKE OF MONDAY/S WIDESPREAD
CONVECTION...THE ATMOSPHERE HAS YET TO RECOVER. OVERALL...VFR IS
EXPECTED THROUGH THE OVERNIGHT HOURS WITH LIGHT SURFACE WINDS.
TOMORROW...VFR WILL CONTINUE WITH BREEZY WINDS AND BROKEN SKIES.
DEPENDING ON WHAT HAPPENS CONVECTION-WISE...IF ANYTHING...FOR
TONIGHT...SHOWERS AND THUNDERSTORMS MAY NEED TO BE ADDED TO THE
TAFS BY A FOLLOWING SHIFT FOR TOMORROW.
PREV DISCUSSION... /ISSUED 256 PM CDT TUE MAY 12 2015/
SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...LARGE THUNDERSTORM
SYSTEM WELL STABILIZED THE LOCAL ATMOSPHERE FOR THE MORNING
HOURS...BUT A FEW SHOWERS HAVE ALREADY BEGUN TO FORM BACK TO THE
WEST THIS AFTERNOON. MOST MODELS SHOW SHOWER ACTIVITY CONTINUING
TO DRIFT GENERALLY NORTHWARD THROUGH THE REST OF THE
AFTERNOON...REMAINING UNCOORDINATED IN NATURE. SOUTHWEST FLOW
ALOFT WILL CONTINUE TO BRING MOISTURE INTO THE REGION ALONG WITH
VARYING ENERGY WAVES CAUGHT IN THE FLOW. THIS WILL HELP PRODUCE
ANOTHER ROUND OF THUNDERSTORM ACTIVITY ON THE MOUNTAINS IN
MEXICO...WHICH WILL THEN DETACH AND DRIFT NE INTO THE RIO GRANDE
PLAINS. ATMOSPHERE IS STILL EXTREMELY MOIST...AND ANY RAINFALL
THAT DOES FALL WILL LIKELY REACH AREAS THAT SAW MORE THAN 5 INCHES
LAST NIGHT. THE FLASH FLOOD WATCH WILL CONTINUE FOR THE COASTAL
COUNTIES THROUGH 8PM AND FOR THE INLAND COUNTIES THROUGH THE NIGHT
INTO TOMORROW MORNING.
LONG TERM /THURSDAY THROUGH MONDAY/...MID LEVEL FLOW WILL BE
CHARACTERIZED BY TROUGHING ACROSS THE WESTERN CONUS AND RIDGING
ACROSS THE EASTERN CONUS. S/W TROUGH FROM THE SHORT TERM PERIOD
WILL BE WELL NORTH OF THE REGION WITH A MUCH STRONGER WAVE COMING
ASHORE ACROSS THE SOUTHWEST PACIFIC COAST. SOUTHWESTERLY FLOW WILL
CONTINUE THROUGH MUCH OF THE PERIOD AND WITH AMPLE MOISTURE AND
WEAK DISTURBANCES MOVING THROUGH THE FLOW...SHOWERS AND STORMS
WILL DEVELOP ACROSS THE HIGHER TERRAIN AND MOVE TOWARDS OUR AREA.
BY THE WEEKEND PWATS LOWER AND WITH A LACK OF GOOD FORCING AND A
SFC FEATURE WILL JUST HAVE ISOLATED SHOWERS AND STORMS. PWATS RAMP
BACK UP LATE SUNDAY AND MONDAY WITH ANOTHER UPPER DISTURBANCE
MOVING ACROSS THE SIERRA MADRES ISOLATED TO SCATTERED CONVECTION
APPEARS PROBABLE. WILL HAVE A SLOW RISE IN TEMPERATURES THROUGH
THE WEEKEND THEN MODERATED SOMEWHAT BY INCREASE IN CLOUDS AND
PRECIPITATION TOWARDS EARLY NEXT WEEK.
MARINE...NOW THROUGH WEDNESDAY NIGHT...SOUTHEAST WINDS WILL
REMAIN ROUGHLY 10 TO 15 KNOTS DURING THE NEXT 36
HOURS...CONTINUING TO PRODUCE LONG FETCH SOUTHEAST WINDS. THIS
FETCH WILL CONTINUE TO PRODUCE SEAS OF 4 TO 7 FEET OFFSHORE
THROUGH THE FORECAST PERIOD. THUNDERSTORM ACTIVITY WILL CONTINUE
TO MOVE ACROSS THE REGION...WITH PERIODS OF EXCESSIVE
RAINFALL...CLOUD TO SFC LIGHTNING AND GUSTY WINDS.
THURSDAY THROUGH SATURDAY...MODERATE SOUTHEAST WINDS WILL PREVAIL
ACROSS THE LOWER TEXAS COASTAL WATERS THIS PERIOD. SMALL CRAFT
EXERCISE CAUTION CONDITIONS APPEAR POSSIBLE SATURDAY ACROSS THE
LAGUNA MADRE AND LATER SATURDAY ACROSS THE GULF WATERS. SMALL
CRAFT ADVISORIES APPEAR POSSIBLE JUST AFTER THIS PERIOD SATURDAY
NIGHT INTO SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 84 76 86 77 / 30 40 30 20
BROWNSVILLE 85 76 87 76 / 30 40 30 20
HARLINGEN 86 75 89 76 / 30 50 30 20
MCALLEN 86 75 89 76 / 30 60 30 20
RIO GRANDE CITY 86 73 89 74 / 40 60 40 30
SOUTH PADRE ISLAND 82 76 82 77 / 30 40 30 20
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL NOON CDT TODAY FOR TXZ248>250-252-253.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...60
LONG TERM...63
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1035 PM MST THU MAY 14 2015
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
STRONG LOW PRESSURE WILL BRING MUCH COOLER TEMPERATURES TO THE REGION
ALONG WITH AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. AS THE
LOW EXITS THE REGION ON SATURDAY...RAIN CHANCES DIMINISH AND
TEMPERATURES RECOVER SLIGHTLY. DRIER AND WARMER CONDITIONS RETURN FOR
SUNDAY INTO NEXT WEEK...BUT EXPECT CONTINUED BELOW NORMAL
TEMPERATURES.
&&
.DISCUSSION... A RATHER PLEASANT...AND BREEZY WEATHER REGIME IS
OCCURRING ACROSS THE REGION THIS EVENING AS A VERY STRONG...AND
MOIST UPPER LOW CENTER APPROACHES FROM THE WEST...WITH MOST LOWER
DESERT LOCATIONS NOW SEEING TEMPERATURES IN THE 60S AND LOW 70S AT
THIS HOUR. ALTHOUGH SOME VIRGA/LIGHT SHOWER ACTIVITY IS ALREADY
BEING DETECTED ON THE 88D RADAR ACROSS SW ARIZONA...WHICH HAS BEEN
HANDLED WELL BY THE LATEST HRRR HI-RES MODEL RUN...IT STILL APPEARS
THAT SIGNIFICANT RAIN WILL NOT BE MOVING INTO OUR CWA UNTIL EARLY
FRIDAY MORNING AT THE EARLIEST...WHEN THE MAIN SHORTWAVE/UPPER LOW
CENTER...THAT CAN ALREADY BE SEEN ON LATEST IR SATELLITE IMAGERY
APPROACHING THE SOUTHERN CA COAST...BEGINS TO MOVE INLAND. AT THIS
POINT...IT APPEARS THAT RAINFALL WILL START DURING THE EARLY MORNING
HOURS ON FRIDAY ACROSS SE CA...THEN WILL REACH THE LOWER COLORADO
RIVER VALLEY BY LATE MORNING ON FRIDAY...THEN MOVE INTO SOUTH-
CENTRAL AZ BY LATE AFTERNOON ON FRIDAY. GIVEN THE TIMING OF THE
RAINFALL AND THE VERY COOL AIRMASS THAT WILL BE MOVING INTO OUR
REGION (850MB TEMPS IN THE 6-10C RANGE)...HIGH TEMPERATURES ON
FRIDAY ARE LIKELY TO BE ANYWHERE FROM 15 TO AS MUCH AS 25 DEGREES
BELOW NORMAL...MORE LIKE MID-LATE WINTER THAN MID-MAY...WITH THE
GREATEST DEPARTURES LIKELY TO BE SEEN OVER SE CA AND THE LOWER
COLORADO RIVER VALLEY. BASED ON THE LATEST (00Z) GFS AND NAM MODEL
RUNS...HAVE DECIDED TO LOWER TOMORROW/S HIGHS A BIT MORE. IT NOW
APPEARS THAT THE RECORD LOW MAX FOR MAY 15TH AT YUMA...WHICH NOW
STANDS AT 72 DEGREES...HAS A GOOD CHANCE OF BEING BROKEN TOMORROW.
HOWEVER...IT APPEARS THAT THE RECORD LOW MAX FOR PHOENIX OF 69
DEGREES FOR THE DATE WILL BE HARDER TO BREAK. LOWS ON SATURDAY
MORNING...GIVEN THE CLEARING SKIES AND THE STILL-COOL
AIRMASS...COULD DROP INTO THE 40S AT SOME OF THE COOLEST RURAL LOWER
DESERT LOCATIONS...NOT BAD FOR MID-MAY!
&&
.PREVIOUS DISCUSSION... UPPER LEVEL LOW PRESSURE CONTINUES TO DEEPEN
OFF THE CENTRAL CALIFORNIA COAST...WITH COPIOUS AMOUNTS OF MOISTURE
STREAMING INTO THE DESERT SOUTHWEST IN ADVANCE OF THE LOW. MOST OF
THE SHOWERS ASSOCIATED WITH THIS LOW REMAIN ACROSS THE L.A.
BASIN...ALTHOUGH PORTIONS OF NORTHERN ARIZONA ARE BEGINNING TO SEE
SHOWERS AND STORMS FILL IN SINCE APPROXIMATELY 18Z. ACROSS THE LOWER
DESERTS HOWEVER...SKIES REMAINED PARTLY CLOUDY WITH DRY CONDITIONS
AND GUSTY SOUTHWEST WINDS. THE STRONGEST WINDS THUS FAR HAVE BEEN
ACROSS SOUTHEAST CALIFORNIA ALTHOUGH WINDS SHOULD REMAIN IN THE
15G25KT RANGE ACROSS THE ENTIRE AREA THROUGH EARLY EVENING. FOR THAT
REASON I WILL HANG ONTO THE MENTIONS OF BLOWING DUST IN THE NORMALLY
FAVORED AREAS ACROSS SOUTHEAST CALIFORNIA...AS WELL AS SOUTH OF THE
PHOENIX METRO.
THE FORECAST REMAINS LARGELY ON TRACK...AS TODAY`S 12Z DETERMINISTIC
GUIDANCE MESHES WELL WITH 12Z GEFS AND NAEFS RUNS. LOW PRESSURE WILL
CONTINUE TO DEEPEN AND SPREAD MOISTURE INTO THE AREA THIS
EVENING/OVERNIGHT AND I WOULD EXPECT TO SEE SHOWERS SPILLING OVER THE
COASTAL MOUNTAINS BY 12Z FRIDAY. EXCELLENT AGREEMENT IS NOTED BETWEEN
TODAY`S GFS AND ECMWF INDICATING A SHORTWAVE TROUGH MOVING THROUGH
CENTRAL ARIZONA MID/LATER AFTERNOON. STRONG ISENTROPIC ASCENT
AND MID LEVEL MOISTURE CONVERGENCE VALUES WHICH RANK IN THE 90TH
PERCENTILE FOR MID MAY WILL ALLOW FOR WIDESPREAD SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT. WENT AHEAD AND INCREASED POPS QUITE A BIT
FOR FRIDAY INTO FRIDAY NIGHT...BASICALLY LOOKING AT A HIGH CONFIDENCE
EVENT WITH WIDESPREAD QUARTER TO HALF INCH RAIN AMOUNTS. WITH MLCAPES
ONLY TOPPING OUT BETWEEN 100-200 J/KG AT ANY GIVEN TIME DURING THIS
EVENT...NOT EXPECTING SEVERE WEATHER TO BE A MAJOR CONCERN. LIKEWISE
I WOULD NOT EXPECT SIGNIFICANT FLOODING BUT COULD ENVISION RUNNING
WASHES ESPECIALLY TO THE NORTH/EAST OF PHOENIX. CONSENSUS OF ALL
GUIDANCE YIELDS QPF AROUND 0.2-0.4 INCHES ACROSS THE DESERTS EAST OF
THE COLORADO RIVER...UPWARDS OF A HALF INCH IN THE MOUNTAINS EAST OF
PHOENIX. NATURALLY...LOWER AMOUNTS CAN BE EXPECTED DOWNWIND OF THE
COASTAL MOUNTAINS IN SOUTHEAST CALIFORNIA.
MUCH COOLER AIR ASSOCIATED WITH THE DEEP TROUGH WILL RESULT IN
SUBSTANTIALLY LOWER TEMPERATURES ON FRIDAY AND SATURDAY. HIGHS FRIDAY
SHOULD ONLY REACH INTO THE LOWER 70S ACROSS A GOOD PORTION OF THE
DESERTS WHILE RECOVERING BACK CLOSER TO 80 DEGREES FOR SATURDAY.
SYNOPTIC FLOW WILL BRIEFLY TURN ZONAL ON SUNDAY WITH 500MB HEIGHTS
RECOVERING BACK TO AROUND 572DM AND HIGH TEMPERATURES IN THE LOW TO
MID 80S.
A GRADUAL DRYING TREND WILL TAKE PLACE STARTING SATURDAY LASTING
INTO NEXT WEEK...BUT DON/T EXPECT TEMPERATURES TO RETURN BACK TO
NORMALS ANYTIME SOON. MODELS AGREE ON ANOTHER...BUT WEAKER...UPPER
LOW FORMING OFF THE WEST COAST ON SUNDAY AND MOVING THROUGH THE
DESERT SOUTHWEST MONDAY INTO EARLY TUESDAY. SO FAR IT DOESN/T LOOK
LIKE ENOUGH MOISTURE OR DYNAMICS WILL BE PRESENT TO WARRANT ANY
SLIGHT CHANCE POPS OVER OUR AREA...BUT THINGS MAY CHANGE. THIS NEXT
TROUGH WILL KEEP TEMPERATURES FROM GETTING BACK TO NORMAL AT LEAST
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A QUITE STRONG (FOR MAY) WEATHER SYSTEM APPROACHING FROM THE WEST IS
EXPECTED TO KEEP THE CURRENT WESTERLY WIND REGIME GOING WELL INTO
TONIGHT...WITH THE TYPICAL SWITCH TO SOUTHWESTERLY WINDS NOT
EXPECTED UNTIL NEAR DAYBREAK...THEN THE WESTERLY WINDS REDEVELOPING
AGAIN BY FRIDAY AFTERNOON...BUT AT LOWER SPEEDS THAN WHAT WE SAW
TODAY. THIS SAME WEATHER SYSTEM IS EXPECTED TO GRADUALLY LOWER CIGS
THROUGH THE REST OF TONIGHT AND INTO FRIDAY...WITH STEADY RAIN
EXPECTED TO DEVELOP BY LATE AFTERNOON ON FRIDAY...AND CONTINUING
INTO THE EVENING. BKN-OVC CIGS ARE EXPECTED TO FALL AOB 5K FEET
DURING THE RAIN EVENT...WITH SCT CLOUD LAYERS AS LOW AS 2-3 K
FEET...AND VISIBILITIES FALLING INTO THE 3-5 MILE RANGE.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WINDS WILL CONTINUE TO GUST TO AROUND 30 KT BEFORE SUBSIDING THIS
EVENING. SHOWERS WILL DEVELOP AT KIPL AROUND 12Z FRIDAY...AND AT
KBLH BY 18Z FRIDAY. THIS SHOWERS WILL LIKELY PUSH CIGS DOWN INTO THE
3-5K FEET RANGE BEFORE GRADUALLY CLEARING/THINNING FRIDAY
EVENING/OVERNIGHT.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...DRIER CONDITIONS WILL OVERSPREAD THE
REGION SUNDAY IN THE WAKE OF THE LOW PRESSURE SYSTEM. ANOTHER STORM
SYSTEM WILL QUICKLY MOVE INTO THE GREAT BASIN BY THE MIDDLE OF THE
WEEK...AND WHILE LITTLE TO NO PRECIPITATION WILL ACCOMPANY THIS
STORM...MOISTURE LEVELS WILL REMAIN UNSEASONABLY HIGH. AFTERNOON
HUMIDITY LEVELS WILL ONLY FALL INTO A 15 TO 25 PERCENT RANGE WITH
GOOD OVERNIGHT RECOVERY AS TEMPERATURES HOVER SLIGHTLY BELOW NORMAL.
WIND SPEEDS DO NOT LOOK UNUSUALLY STRONGER...WITH JUST THE TYPICAL
AFTERNOON UPSLOPE GUSTINESS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/LEINS/KUHLMAN
AVIATION...PERCHA
FIRE WEATHER...MO/HIRSCH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
930 PM MST THU MAY 14 2015
&&
.SYNOPSIS...
STRONG LOW PRESSURE WILL BRING MUCH COOLER TEMPERATURES TO THE REGION
ALONG WITH AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. AS THE
LOW EXITS THE REGION ON SATURDAY...RAIN CHANCES DIMINISH AND
TEMPERATURES RECOVER SLIGHTLY. DRIER AND WARMER CONDITIONS RETURN FOR
SUNDAY INTO NEXT WEEK...BUT EXPECT CONTINUED BELOW NORMAL
TEMPERATURES.
&&
.DISCUSSION... A RATHER PLEASANT...AND BREEZY WEATHER REGIME IS
OCCURRING ACROSS THE REGION THIS EVENING AS A VERY STRONG...AND
MOIST UPPER LOW CENTER APPROACHES FROM THE WEST...WITH MOST LOWER
DESERT LOCATIONS NOW SEEING TEMPERATURES IN THE 60S AND LOW 70S AT
THIS HOUR. ALTHOUGH SOME VIRGA/LIGHT SHOWER ACTIVITY IS ALREADY
BEING DETECTED ON THE 88D RADAR ACROSS SW ARIZONA...WHICH HAS BEEN
HANDLED WELL BY THE LATEST HRRR HI-RES MODEL RUN...IT STILL APPEARS
THAT SIGNIFICANT RAIN WILL NOT BE MOVING INTO OUR CWA UNTIL EARLY
FRIDAY MORNING AT THE EARLIEST...WHEN THE MAIN SHORTWAVE/UPPER LOW
CENTER...THAT CAN ALREADY BE SEEN ON LATEST IR SATELLITE IMAGERY
APPROACHING THE SOUTHERN CA COAST...BEGINS TO MOVE INLAND. AT THIS
POINT...IT APPEARS THAT RAINFALL WILL START DURING THE EARLY MORNING
HOURS ON FRIDAY ACROSS SE CA...THEN WILL REACH THE LOWER COLORADO
RIVER VALLEY BY LATE MORNING ON FRIDAY...THEN MOVE INTO SOUTH-
CENTRAL AZ BY LATE AFTERNOON ON FRIDAY. GIVEN THE TIMING OF THE
RAINFALL AND THE VERY COOL AIRMASS THAT WILL BE MOVING INTO OUR
REGION (850MB TEMPS IN THE 6-10C RANGE)...HIGH TEMPERATURES ON
FRIDAY ARE LIKELY TO BE ANYWHERE FROM 15 TO AS MUCH AS 25 DEGREES
BELOW NORMAL...MORE LIKE MID-LATE WINTER THAN MID-MAY...WITH THE
GREATEST DEPARTURES LIKELY TO BE SEEN OVER SE CA AND THE LOWER
COLORADO RIVER VALLEY. BASED ON THE LATEST (00Z) GFS AND NAM MODEL
RUNS...HAVE DECIDED TO LOWER TOMORROW/S HIGHS A BIT MORE. IT NOW
APPEARS THAT THE RECORD LOW MAX FOR MAY 15TH AT YUMA...WHICH NOW
STANDS AT 72 DEGREES...HAS A GOOD CHANCE OF BEING BROKEN TOMORROW.
HOWEVER...IT APPEARS THAT THE RECORD LOW MAX FOR PHOENIX OF 69
DEGREES FOR THE DATE WILL BE HARDER TO BREAK. LOWS ON SATURDAY
MORNING...GIVEN THE CLEARING SKIES AND THE STILL-COOL
AIRMASS...COULD DROP INTO THE 40S AT SOME OF THE COOLEST RURAL LOWER
DESERT LOCATIONS...NOT BAD FOR MID-MAY!
&&
.PREVIOUS DISCUSSION... UPPER LEVEL LOW PRESSURE CONTINUES TO DEEPEN
OFF THE CENTRAL CALIFORNIA COAST...WITH COPIOUS AMOUNTS OF MOISTURE
STREAMING INTO THE DESERT SOUTHWEST IN ADVANCE OF THE LOW. MOST OF
THE SHOWERS ASSOCIATED WITH THIS LOW REMAIN ACROSS THE L.A.
BASIN...ALTHOUGH PORTIONS OF NORTHERN ARIZONA ARE BEGINNING TO SEE
SHOWERS AND STORMS FILL IN SINCE APPROXIMATELY 18Z. ACROSS THE LOWER
DESERTS HOWEVER...SKIES REMAINED PARTLY CLOUDY WITH DRY CONDITIONS
AND GUSTY SOUTHWEST WINDS. THE STRONGEST WINDS THUS FAR HAVE BEEN
ACROSS SOUTHEAST CALIFORNIA ALTHOUGH WINDS SHOULD REMAIN IN THE
15G25KT RANGE ACROSS THE ENTIRE AREA THROUGH EARLY EVENING. FOR THAT
REASON I WILL HANG ONTO THE MENTIONS OF BLOWING DUST IN THE NORMALLY
FAVORED AREAS ACROSS SOUTHEAST CALIFORNIA...AS WELL AS SOUTH OF THE
PHOENIX METRO.
THE FORECAST REMAINS LARGELY ON TRACK...AS TODAY`S 12Z DETERMINISTIC
GUIDANCE MESHES WELL WITH 12Z GEFS AND NAEFS RUNS. LOW PRESSURE WILL
CONTINUE TO DEEPEN AND SPREAD MOISTURE INTO THE AREA THIS
EVENING/OVERNIGHT AND I WOULD EXPECT TO SEE SHOWERS SPILLING OVER THE
COASTAL MOUNTAINS BY 12Z FRIDAY. EXCELLENT AGREEMENT IS NOTED BETWEEN
TODAY`S GFS AND ECMWF INDICATING A SHORTWAVE TROUGH MOVING THROUGH
CENTRAL ARIZONA MID/LATER AFTERNOON. STRONG ISENTROPIC ASCENT
AND MID LEVEL MOISTURE CONVERGENCE VALUES WHICH RANK IN THE 90TH
PERCENTILE FOR MID MAY WILL ALLOW FOR WIDESPREAD SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT. WENT AHEAD AND INCREASED POPS QUITE A BIT
FOR FRIDAY INTO FRIDAY NIGHT...BASICALLY LOOKING AT A HIGH CONFIDENCE
EVENT WITH WIDESPREAD QUARTER TO HALF INCH RAIN AMOUNTS. WITH MLCAPES
ONLY TOPPING OUT BETWEEN 100-200 J/KG AT ANY GIVEN TIME DURING THIS
EVENT...NOT EXPECTING SEVERE WEATHER TO BE A MAJOR CONCERN. LIKEWISE
I WOULD NOT EXPECT SIGNIFICANT FLOODING BUT COULD ENVISION RUNNING
WASHES ESPECIALLY TO THE NORTH/EAST OF PHOENIX. CONSENSUS OF ALL
GUIDANCE YIELDS QPF AROUND 0.2-0.4 INCHES ACROSS THE DESERTS EAST OF
THE COLORADO RIVER...UPWARDS OF A HALF INCH IN THE MOUNTAINS EAST OF
PHOENIX. NATURALLY...LOWER AMOUNTS CAN BE EXPECTED DOWNWIND OF THE
COASTAL MOUNTAINS IN SOUTHEAST CALIFORNIA.
MUCH COOLER AIR ASSOCIATED WITH THE DEEP TROUGH WILL RESULT IN
SUBSTANTIALLY LOWER TEMPERATURES ON FRIDAY AND SATURDAY. HIGHS FRIDAY
SHOULD ONLY REACH INTO THE LOWER 70S ACROSS A GOOD PORTION OF THE
DESERTS WHILE RECOVERING BACK CLOSER TO 80 DEGREES FOR SATURDAY.
SYNOPTIC FLOW WILL BRIEFLY TURN ZONAL ON SUNDAY WITH 500MB HEIGHTS
RECOVERING BACK TO AROUND 572DM AND HIGH TEMPERATURES IN THE LOW TO
MID 80S.
A GRADUAL DRYING TREND WILL TAKE PLACE STARTING SATURDAY LASTING
INTO NEXT WEEK...BUT DON/T EXPECT TEMPERATURES TO RETURN BACK TO
NORMALS ANYTIME SOON. MODELS AGREE ON ANOTHER...BUT WEAKER...UPPER
LOW FORMING OFF THE WEST COAST ON SUNDAY AND MOVING THROUGH THE
DESERT SOUTHWEST MONDAY INTO EARLY TUESDAY. SO FAR IT DOESN/T LOOK
LIKE ENOUGH MOISTURE OR DYNAMICS WILL BE PRESENT TO WARRANT ANY
SLIGHT CHANCE POPS OVER OUR AREA...BUT THINGS MAY CHANGE. THIS NEXT
TROUGH WILL KEEP TEMPERATURES FROM GETTING BACK TO NORMAL AT LEAST
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
GUSTY WINDS AHEAD OF AN APPROACHING COLD FRONT WILL BE THE PRIMARY
AVIATION WEATHER IMPACT. WINDS WILL CONTINUE TO VEER TO THE SOUTHWEST
THIS AFTERNOON WITH GUSTS AS HIGH AS 30 KT. THE WINDY CONDITIONS WILL
ABATE THIS EVENING...THOUGH THE TYPICAL SHIFT TO DOWNSLOPE EASTERLY
IS NOT EXPECTED. INSTEAD...WINDS WILL BECOME SOUTHEASTERLY AROUND
12Z. CLOUDS WILL ALSO LOWER TO AROUND 6K FT FRIDAY MORNING.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WINDS WILL CONTINUE TO GUST TO AROUND 30 KT BEFORE SUBSIDING THIS
EVENING. SHOWERS WILL DEVELOP ACROSS SOUTHEASTERN CALIFORNIA AROUND
12Z FRIDAY...WITH INCREASING CHANCES FOR PRECIPITATION THROUGH FRIDAY
AFTERNOON.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...DRIER CONDITIONS WILL OVERSPREAD THE
REGION SUNDAY IN THE WAKE OF THE LOW PRESSURE SYSTEM. ANOTHER STORM
SYSTEM WILL QUICKLY MOVE INTO THE GREAT BASIN BY THE MIDDLE OF THE
WEEK...AND WHILE LITTLE TO NO PRECIPITATION WILL ACCOMPANY THIS
STORM...MOISTURE LEVELS WILL REMAIN UNSEASONABLY HIGH. AFTERNOON
HUMIDITY LEVELS WILL ONLY FALL INTO A 15 TO 25 PERCENT RANGE WITH
GOOD OVERNIGHT RECOVERY AS TEMPERATURES HOVER SLIGHTLY BELOW NORMAL.
WIND SPEEDS DO NOT LOOK UNUSUALLY STRONGER...WITH JUST THE TYPICAL
AFTERNOON UPSLOPE GUSTINESS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/LEINS/KUHLMAN
AVIATION...MO
FIRE WEATHER...MO/HIRSCH
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 PM PDT THU MAY 14 2015
.SYNOPSIS...
A NORTH PACIFIC STORM SYSTEM WILL CONTINUE TO BRING SHOWERS AND
ISOLATED THUNDERSTORMS THROUGH FRIDAY. LOCALLY HEAVY RAIN MAY
PRODUCE FLASH FLOODING...ESPECIALLY IN SAN DIEGO COUNTY. SNOW WILL
FALL ABOVE 5500 TO 6000 FEET. THE SYSTEM WILL MOVE EAST OUT OF THE
AREA FRIDAY NIGHT...AND FAIR BUT COOL WEATHER WILL OCCUR OVER THE
WEEKEND WITH AREAS OF MAINLY NIGHT AND MORNING LOW CLOUDS WEST OF
THE MOUNTAINS. A FEW SHOWERS ARE POSSIBLE NEXT MONDAY...BUT
OTHERWISE THE COOL WEATHER WITH AREAS OF COASTAL AND VALLEY LOW
CLOUDS WILL CONTINUE.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING
ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES...
AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN
OCCURRING...WITH CONVECTIVE BANDING BRINGING LOCALLY HEAVY
RAINFALL OVER AN INCH WHERE TRAINING OF THE PRECIPITATION IS
OCCURRING ALONG THE BANDS. SAN DIEGO LINDBERGH FIELD HAD 1.51 INCHES
IN ABOUT 90 MINUTES...INCLUDING 0.71 INCHES IN 9 MINUTES...MORE
TYPICAL OF A CONVECTIVE STORM IN THE MIDWEST OR SOUTHEAST THAN SAN
DIEGO. FLASH FLOOD WARNING IS IN EFFECT FOR THE CITY OF SAN
DIEGO...AND WE HAVE HAD A REPORT OF FLOODING ALONG INTERSTATE 8.
PRECIPITABLE WATER VALUES OF AROUND ONE INCH ARE QUITE RARE FOR
MAY...AND THAT IS COMBINING WITH THE COLD AIR ALOFT...AROUND -22 DEG
C AT 500 MB...TO BRING THE POTENT CONVECTIVE CELLS. HRRR SHOWS THE
CONVECTIVE BANDING CONTINUING OVERNIGHT AHEAD OF THE MAIN LOW OVER
THE COASTAL WATERS...AND THIS WILL MEAN THAT SOME LOCATIONS WILL
HAVE HEAVY RAINFALL WHILE ADJACENT AREAS WILL HAVE RELATIVELY LIGHT
AMOUNTS...WITH HEAVY RAINFALL MOST LIKELY IN SAN DIEGO COUNTY AND
SOUTHWESTERN RIVERSIDE COUNTY. THE RAINFALL DOES BECOME MORE
WIDESPREAD AGAIN TOWARDS SUNRISE...BUT THE HRRR DOES SHOW THE
EAST-WEST ORIENTED FRONT THAT THE LOCAL WRF WAS ADVERTISING
YESTERDAY OVER THE COASTAL WATERS OFF NORTHERN SAN DIEGO COUNTY
WHICH COULD MEAN THAT THE FOCUS OF THE HEAVIEST PRECIP WILL BE IN
NORTHERN SAN DIEGO COUNTY IN THE MORNING...THEN THE NAM IS
INDICATING IT SHOULD SLIDE A BIT FURTHER SOUTH AS THE SURFACE LOW
OVER THE COASTAL WATERS SHIFTS SOUTHEAST. PRECIP AMOUNTS WILL BE
QUITE VARIABLE...BUT SAN DIEGO COUNTY WILL HAVE MOSTLY 1.0 TO 2.5
INCHES WITH LOCAL AMOUNTS TO 3 INCHES. NORTH OF SAN DIEGO COUNTY
WILL MOSTLY BE 1-2 INCHES. THE DESERTS WILL HAVE LESS...MOSTLY 0.1
TO 0.4 INCHES. SOME OROGRAPHICS HAVE OCCURRED TONIGHT...AS AMOUNTS
WERE ENHANCED ON THE SOUTHWEST SLOPES...INCLUDING AROUND PALOMAR
MOUNTAIN AND IN SAN BERNARDINO COUNTY. HOWEVER...WITH WINDS BECOMING
MORE SOUTHERLY AND MORE CYCLONIC AS THE LOW CENTER
APPROACHES...AND WE CONTINUE TO HAVE MORE CONVECTIVE THAN
STRATIFORM PRECIP...THE OROGRAPHIC EFFECT WILL BE LESS AND MOUNTAIN
AREAS WILL HAVE ONLY SLIGHTLY MORE PRECIP THAN COASTAL/VALLEY
LOCATIONS. REGARDING SNOW...THAT WILL ALSO BE HIGHLY VARIABLE...AND
WHILE AMOUNTS WILL GENERALLY BE 2-6 INCHES IN THE SAN BERNARDINO
COUNTY MOUNTAINS...ANY KIND OF TRAINING OF PRECIP COULD BRING HIGHER
LOCAL AMOUNTS...9 INCHES...POSSIBLY MORE. SNOW LEVELS WILL MOSTLY BE
5500-6000 FEET. NOT SURPRISINGLY...DAYTIME TEMPS WILL BE WELL BELOW
SEASONAL NORMALS...WITH SOME LOWER DESERT AREAS NOT EVEN MUCH ABOVE
70 FRIDAY.
MOST OF THE PRECIP SHOULD END EARLY FRIDAY NIGHT...BUT WITH VERY
LITTLE RIDGING BEHIND THIS LOW PRESSURE SYSTEM...TEMPS WILL REMAIN
BELOW NORMAL OVER THE WEEKEND...WITH HIGHS MOSTLY 10 DEG F BELOW
NORMAL. ANOTHER RATHER DEEP TROUGH WILL MOVE THROUGH MONDAY...THOUGH
WITH LIMITED MOISTURE. A FEW SHOWERS COULD STILL
DEVELOP...ESPECIALLY SINCE WE WILL LIKELY HAVE A DEEP MARINE LAYER
THEN. LONG-WAVE TROUGHING ALONG THE WEST COAST FOR MOST OF NEXT WEEK
WILL MEAN TEMPERATURES WILL REMAIN BELOW NORMAL FOR AWHILE WITH
OCCSAIONAL CLOUDS...ESPECIALLY WEST OF THE MOUNTAINS.
&&
.AVIATION...
150400Z...SCATTERED SHRA AND ISOLATED TSRA WILL CONTINUE ACROSS
PORTIONS OF THE REGION THIS EVENING...ESPECIALLY NEAR KSAN AND KCRQ.
NUMEROUS SHOWERS WILL DEVELOP AND MOVE ACROSS THE AREA EARLY FRIDAY
MORNING THROUGH EARLY FRIDAY AFTERNOON AS A FRONT TRAVERSES THE
REGION. CEILINGS WILL BE MOSTLY ABOVE 4000-5000 FT MSL...THEN LOWER
IN SHOWERS TO BETWEEN 1500 TO 2500 FT MSL IN SHOWERS. VIS WILL ALSO
LOWER TO BETWEEN 2-4SM IN SHOWERS...LOCALLY 1SM IN HEAVIER SHOWERS.
STRONG UP/DOWN DRAFTS...SMALL HAIL...LIGHTNING AND REDUCED VIS WILL
BE POSSIBLE IN THUNDERSTORMS. CONDITIONS WILL IMPROVE FRIDAY EVENING
AND FRIDAY NIGHT.
&&
.MARINE...
900 PM...A STORM SYSTEM WILL CONTINUE SHOWERS AND
THUNDERSTORMS ACROSS THE COASTAL WATERS THIS EVENING...AND INCREASE
IN COVERAGE TONIGHT AND FRIDAY MORNING. THUNDERSTORMS MAY CREATE
SMALL HAIL...GUSTY WINDS...LIGHTNING...AND BRIEF HEAVY RAINFALL.
WATERSPOUTS WILL ALSO BE POSSIBLE. A MARINE WEATHER
STATEMENT...LAXMWSSGX...HAS BEEN ISSUED. GUSTY SOUTH TO
SOUTHEASTERLY WINDS TO 30 KT WILL LIKELY DEVELOP FRIDAY MORNING AND
CONTINUE THROUGH THE AFTERNOON. CHOPPY SEAS AND HAZARDOUS CONDITIONS
ARE EXPECTED FOR SMALL CRAFT. A SMALL CRAFT ADVISORY HAS BEEN
ISSUED...LAXMWWSGX...AND GOES INTO EFFECT FRIDAY MORNING. WINDS AND
SEAS WILL DIMINISH FRIDAY NIGHT AND SATURDAY...WITH NO ADDITIONAL
HAZARDOUS MARINE WEATHER EXPECTED THROUGH MONDAY.
&&
.SKYWARN...
SKYWARN ACTIVATION WILL LIKELY BE NEEDED FRIDAY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM PDT
FRIDAY FOR RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY
MOUNTAINS.
FLASH FLOOD WATCH FROM 4 AM PDT FRIDAY THROUGH 6 PM FRIDAY FOR
RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SANTA
ANA MOUNTAINS AND FOOTHILLS-SAN DIEGO COUNTY COASTAL AREAS.
PZ...SMALL CRAFT ADVISORY FROM 5 AM FRIDAY TO 5 AM PDT SATURDAY FOR
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING
30 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 PM PDT FRIDAY FOR COASTAL
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
TO 30 NM.
&&
$$
PUBLIC...MAXWELL
AVIATION/MARINE...JJT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
410 AM EDT FRI MAY 15 2015
.SYNOPSIS...
DRY WEATHER THIS AFTERNOON UNDER HIGH PRESSURE AT THE SURFACE AND
ALOFT. THE CHANCE FOR RAIN WILL INCREASE SLIGHTLY THROUGH THE
WEEKEND AS MOISTURE RETURNS TO THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER RIDGE AXIS EXTENDING FROM THE WESTERN
ATLANTIC NORTH THROUGH THE CAROLINAS TO THE EASTERN GREAT LAKES.
SURFACE HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COAST.
ATMOSPHERIC MOISTURE GRADIENT ACROSS THE REGION WITH DRIER AIR TO
THE EAST AND MORE MOISTURE TO THE WEST. UPPER IMPULSE CURRENTLY
MOVING SLOWLY EAST ACROSS N AND CENT GA...WILL MOVE SLOWLY EAST
THROUGH THE RIDGE AXIS ACROSS OUR FA LATER THIS MORNING AND TO OUR
EAST BY THIS AFTERNOON. A FEW PATCHES OF LIGHT RAIN ACROSS
PORTIONS OF CENT GA MOVING EAST BUT GENERALLY APPEAR TO BE
WEAKENING. A FEW LIGHT SHOWERS POSSIBLE THIS MORNING AHEAD OF THE
UPPER IMPULSE. LATER TODAY...MODEL FORECAST SOUNDINGS INDICATE
MID LEVEL CAPPING DUE TO THE UPPER RIDGE AXIS AND GENERALLY
LIMITED MOISTURE OVER MOST OF THE FA. HOWEVER...DIURNAL HEATING
MAY PROVIDE A CATALYST FOR SOME ISOLATED TO WIDELY SCATTERED
SHALLOW SHOWER ACTIVITY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE
WILL BE OVER THE WESTERN ATLANTIC WITH SOUTHEASTERLY FLOW PUSHING
MOISTURE BACK INTO THE REGION. BEST INSTABILITY WILL BE ACROSS
THE UPSTATE. MAJORITY OF THE CWA WILL REMAIN DRY THROUGH THE
PERIOD. AFTERNOON HIGH TEMPERATURES WILL BE IN THE MID 80S
SATURDAY AND OVERNIGHT LOWS IN THE LOW TO MID 60S EACH NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH A HIGHLY
AMPLIFIED PATTERN DOMINATING THE COUNTRY. THIS WILL KEEP AN UPPER
LEVEL RIDGE OVER THE EASTERN US WITH MOIST SOUTHERLY FLOW
PERSISTING OVER THE FORECAST AREA THROUGH THE MIDDLE OF THE WEEK.
EXPECTING MAINLY DIURNAL SHOWER/STORM ACTIVITY THROUGH A MAJORITY
OF THE PERIOD. A WEAK FRONTAL BOUNDARY WILL STRUGGLE TO CROSS THE
REGION ON WEDNESDAY WITH MODELS INDICTING THE FRONT SHEARING APART
AND STALLING OVER THE REGION FOR THURSDAY. WITH THE RUN TO RUN
CONSISTENCY OF THE LONG TERM MODELS CHANGES TO THE FORECAST HAVE
BEEN MINOR. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY TO
ABOVE NORMAL.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS HAVE DEVELOPED ACROS THE CSRA. A LOW LEVEL E TO SE FLOW
EXPECTED TO RESULT IN MVFR CIGS...POSSIBLY IFR...THROUGH THIS
MORNING FOR PORTIONS OF THE REGION. LATEST HRRR KEEPS LOWER CIGS
MAINLY NEAR THE CSRA IN THE NEAR TERM. DIURNAL HEATING EXPECTED
TO PROVIDE A GRADUAL RETURN TO VFR BY AFTERNOON. A FEW SHOWERS
WILL BE POSSIBLE BUT CHANCES NOT SUFFICIENT TO INCLUDE MENTION IN
THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN DIURNAL
CONVECTION THROUGH THE WEEKEND.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BOISE ID
331 AM MDT FRI MAY 15 2015
.SHORT TERM...TODAY THROUGH SATURDAY...NUMEROUS SHOWERS ARE
LIFTING FROM THE SE TO THE NW ACROSS SW IDAHO AND SE
OREGON...GENERALLY IN AN ARC FROM THE STEENS MTN OREGON TO
FAIRFIELD IDAHO. SOUTH OF THIS AREA IS A BIT OF A DRY SLOT OVER NE
NV. HRRR LIFTS THE ARC TO THE NW THIS MORNING THEN SLOWS IT
TOWARDS NOON OVER BAKER COUNTY...AND BREAKS OUT MORE SHOWERS IN
THE DRY SLOT AS IT LIFTS ACROSS SW ID AND JORDAN VALLEY. CALIBRATED
SREF SHOWS GREATEST THUNDERSTORM THREAT ACROSS SW IDAHO THIS
AFTERNOON AND EVENING. PWAT IN THE 70-80TH PERCENTILE THROUGH THE
SHORT TERM AS UNSETTLED WEATHER WITH SHOWERS AND LATE DAY
THUNDERSTORMS CONTINUE OVER IDAHO ESPECIALLY. TEMPERATURES AVERAGE
AROUND 5 TO 10 DEGREES BELOW NORMAL IN THE SHORT TERM.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...MODELS CONTINUE TO
SHOW AN ACTIVE AND WET PATTERN AS A BROAD TROUGH CONTINUES TO
DOMINATE THE MID AND LONG TERM. A SERIES OF CLOSED LOWS ARE
EXPECTED TO MOVE SOUTH ALONG THE PACIFIC COAST CONTINUING THE
CHANCE OF SHOWERS AND AFTERNOON THUNDERSTORMS. HEAVIER BANDS OF
PRECIP AND BRIEF DRY PERIODS WILL EXIST...BUT POPS REFLECT AN
OVERALL UNSETTLED FORECAST. TEMPERATURES ARE EXPECTED TO REMAIN
WITHING 5 DEGREES OF NORMAL THROUGH THE PERIOD.
&&
.AVIATION...MOSTLY VFR WITH BKN-OVC CLOUD COVER. SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH PERIOD...WITH MVFR POSSIBLE WITH
HEAVIER SHOWERS AND IN THE MTNS. SURFACE WINDS GENERALLY 12 KTS OR
LESS WITH GUSTS NEAR SHOWERS/THUNDERSTORMS. WINDS ALOFT NEAR 10K FT
MSL...NORTH 15-30 KTS.
WEEKEND OUTLOOK...SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE
THROUGH THE WEEKEND...ESPECIALLY IN THE AFTERNOONS. CEILINGS
EXPECTED TO REMAIN LOW VFR/MVFR DURING THIS TIME.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...VM
LONG TERM/AVIATION...EP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
255 AM CDT FRI MAY 15 2015
.UPDATE...
941 PM CDT
LIGHTNING STRIKES HAVE BEEN LIMITED SOUTH OF THE AREA THIS
EVENING. WHILE THE FIRST MAIN WAVE OF RAIN IS THROUGH...ADDITIONAL
SHOWERS WILL CONTINUE THIS EVENING AREA WIDE...WITH THE FOCUS
SHIFTING FARTHER SOUTH THROUGH THE NIGHT. WHILE THE THUNDER WAS
REMOVED FOR THE EVENING PERIOD...WILL HOLD ONTO THE ISOLATED
THUNDER MENTION OVERNIGHT AS BETTER LAPSE RATES ALOFT ADVECT
NORTHWARD AND RAP HANGS ONTO SOME WEAK MOST UNSTABLE CAPE. ONE
LONE CLOUD TO GROUND STRIKE OCCURRED IN CHAMPAIGN COUNTY NOT TOO
LONG AGO. AREAS SOUTH OF I-80 HOLD THE BEST CHANCE FOR AN ISOLATED
STRIKE OR TWO.
KMD
&&
.SHORT TERM...
253 PM CDT
THROUGH FRIDAY...
AN ELONGATED NEGATIVELY-TILTED UPPER TROUGH...EXTENDING FROM THE RED
RIVER VALLEY OF THE NORTH TO SOUTHERN ILLINOIS THIS AFTERNOON...WILL
CONTINUE ITS ADVANCE NORTHEAST TONIGHT. WHILE THERE ARE MULTIPLE
EMBEDDED SHORT WAVE IMPULSES WITHIN THIS...THE MOST PRONOUNCED FOR
OUR AREA IS A CIRCULATION CENTER NEAR THE IA/MO/IL BORDER. FOCUSED
ASCENT JUST AHEAD OF THIS IS IN TANDEM WITH A 40 KT LOW-LEVEL JET
PER ILX AND LSX VWP DATA...AND REGIONAL RADAR MOSAIC INDICATES
SHOWERS INCREASING IN COVERAGE AND INTENSITY ACROSS WESTERN ILLINOIS
AND EASTERN MISSOURI AS OF 230 PM.
THIS FAVORED AREA OF FORCING AND SHOWERS WILL EXPAND INTO THE
ILLINOIS FORECAST AREA BY EARLY EVENING. HAVE GONE AS DETERMINISTIC
AS COULD WITH HOURLY POPS...LEVERAGING SOME ON CONVECTIVE ALLOWING
MODELS/ENSEMBLES AND MORE SO OBSERVATIONAL TRENDS. DEEPER PWATS
AROUND 1.4 INCHES AND SLIGHTLY BETTER LAPSE RATES ALOFT IMMEDIATELY
AHEAD OF THE CIRCULATION SUPPORT CHANCES FOR ISOLATED EMBEDDED
THUNDER THIS EVENING. TOO LITTLE OF RECOVERY TIME FOR LAPSE RATES
SHOULD STUNT ANY SEVERE WEATHER THREAT.
THE MAIN CHANGE WITH THE FORECAST FOR TONIGHT WAS TO DIMINISH...AND
IN MANY PLACES END... POPS EARLIER OVERNIGHT FROM SOUTHWEST TO
NORTHEAST...BASED HEAVILY ON UPSTREAM OBSERVATIONAL TRENDS WITH HOUR-
TO-HOUR RUNS OF THE RAP/HRRR SEEM TO BE CATCHING UP ON. EXPECT THE
ILLINOIS FORECAST AREA TO HAVE THE LONGEST TIME WITH SHOWERS
/4-6 HOURS/ AND SOME PLACES TO FINISH AROUND ONE HALF INCH...WHILE
TAPERING TO NEAR OR UNDER ONE QUARTER OF AN INCH INTO NORTHWEST
INDIANA.
SIZABLE PRESSURE FALLS AT THE SURFACE WILL KEEP UP SOUTHEAST WINDS
TONIGHT AND TEMPERATURES REALLY SHOULD ONLY DROP BY WET BULB
COOLING. THE WINDS SHOULD ALSO PREVENT FOG FROM BEING MUCH OF A
PROBLEM ONCE THE RAIN ENDS...AT LEAST OVER LAND. LOWS ARE EXPECTED
IN THE MID-UPPER 50S AREAWIDE.
DURING THE DAY FRIDAY FORCING IS FAIRLY MINIMAL FOR RAIN...SO
CONTINUE POPS LOW OR NON-MENTIONABLE. A SYNOPTIC BOUNDARY STARTS TO
TAKE SHAPE FROM EAST-TO-WEST ACROSS CENTRAL ILLINOIS AND
CONVERGENCE/MOISTURE TRANSPORT INTO AND ALONG THIS WILL START TO
GRADUALLY STRENGTHEN DURING THE AFTERNOON. THIS IS WHERE HAVE KEPT
THE POPS. CONFIDENCE IS SOMEWHAT SHAKE ON HOW QUICKLY CLOUDS
SCATTER...BUT HAVE HIGHS RECOVERING FROM MID 70S TO LOWER 80S FROM
NORTH-TO-SOUTH.
MTF
&&
.LONG TERM...
253 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
UPPER LEVEL RIDGING WILL TRANSLATE ACROSS NORTHERN ILLINOIS FRIDAY
NIGHT INTO EARLY SATURDAY HOWEVER BOTH THE NAM AND GFS ADVERTISE
A SUBTLE SHORTWAVE EMBEDDED WITHIN THE UPPER RIDGE LIFTING ACROSS
THE AREA FRIDAY NIGHT. SOUNDINGS SHOW MODEST INSTABILITY WILL BE
IN PLACE OVERNIGHT AND ANY LIFT ASSOCIATED WITH THE SHORTWAVE MAY
BE ABLE TO TRIGGER A FEW THUNDERSTORMS. FORCING IS OTHERWISE
FAIRLY WEAK SO THINK COVERAGE SHOULD BE FAIRLY SCATTERED.
MEANWHILE...JET STREAM ROUNDING THE BASE OF THE LONGWAVE TROUGH
CENTERED OVER THE INTERMOUNTAIN WEST WILL LIFT INTO THE CENTRAL
PLAINS SATURDAY WITH SURFACE LOW DEVELOPING OVER WESTERN KS/NE
SATURDAY AFTERNOON. THE MIDWEST WILL ALREADY BE UNDER A MOIST
AIRMASS WITH WIDE OPEN GULF...BUT THIS NEXT WAVE WILL FURTHER
INCREASE MOISTURE WITH PWATS PUSHING 1.5-1.6 INCHES BY LATER IN THE
DAY SATURDAY. HIGHS IN THE LOW TO MID 80S AND SURFACE DEW POINTS IN
THE MID 60S WILL RESULT IN MODERATE INSTABILITY ACROSS THE
AREA...WEAKLY CAPPED OR UNCAPPED PER FORECAST SOUNDINGS. MOST
MODELS INDICATE WIDESPREAD CONVECTIVE ACTIVITY IN THE WARM
SECTOR ACROSS THE MIDWEST AND MISSISSIPPI RIVER VALLEY WHILE THE
MOST FOCUSED FORCING REMAINS WEST OF THE MISSISSIPPI RIVER. GIVEN
THE INSTABILITY AND WEAK FORCING...WILL BE HARD TO PIN DOWN MOST
FAVORED AREAS FOR THUNDERSTORM ACTIVITY BUT GENERALLY EXPECT
SCATTERED UNORGANIZED ACTIVITY WHICH MAY END UP BEING DIURNALLY
FAVORED.
A LOW LEVEL JET FORMS SATURDAY NIGHT FOCUSED ACROSS THE MID-
MISSOURI VALLEY AND SHIFTING EAST ACROSS IOWA DURING THE
OVERNIGHT HOURS. BEST PRECIP CHANCES WILL BE ACROSS THESE AREAS
SATURDAY NIGHT WHILE MODELS CONTINUE TO PRODUCE WIDELY SCATTERED
UNORGANIZED ACTIVITY ACROSS THE LOCAL FORECAST AREA GIVEN THE
CONTINUED INSTABILITY.
SUNDAY CONTINUES TO APPEAR AT LEAST FAVORABLE FOR SEVERE WEATHER
IN THE AREA. EARLY DAY SOUNDINGS SHOW A CAP IN PLACE WHICH
SHOULD HELP ANY FESTERING NOCTURNAL CONVECTION MOVING IN FROM OUR
WEST DISSIPATE...AND FOR INSTABILITY TO BUILD THROUGH THE MORNING
AND EARLY AFTERNOON. MID/HIGH LEVEL CLOUD COVER MAY IMPEDE
INSOLATION SOME...HOWEVER GUIDANCE CONTINUES TO ADVERTISE A
CORRIDOR OF 1000+ J/KG MLCAPE AHEAD OF THE COLD FRONT MOVING
ACROSS NORTHERN ILLINOIS LATE AFTERNOON INTO THE EVENING. IN
ADDITION...NEGATIVELY TILTED TROUGH IS PROGGED TO LIFT INTO THE
UPPER MIDWEST SUNDAY WHICH SHOULD HELP ERODE THE CAP...AND THE JET
STREAM ADVECTS OVERHEAD RESULTING IN INCREASING DEEP LAYER SHEAR.
LATEST GFS ADVERTISES 35-45 KT OF FAIRLY UNIDIRECTIONAL 0-6KM
SHEAR MOVING OVER THE AREA WHICH WILL BE SUFFICIENT TO SUPPORT AN
ORGANIZED SEVERE WEATHER THREAT SHOULD THE INSTABILITY AND FORCING
MATERIALIZE AS EXPECTED.
THE COLD FRONT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWEST
INDIANA EARLY ON MONDAY WITH INITIALLY BREEZY NORTHWEST/NORTH WIND
BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. COLD ADVECTION AND WINDS TURNING OFF OF LAKE MICHIGAN
WILL RESULT IN TEMPERATURES RETURNING TO COLDER THAN NORMAL
LEVELS...ESPECIALLY TUESDAY WHERE HIGHS MAY ONLY TOP OUT IN THE
50S...THEN GRADUALLY MODERATING AS WE HEAD THROUGH MIDWEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* INTERMITTENT SHRA CONTINUES THROUGH THE EARLY OVERNIGHT HOURS.
* CIGS LOWER TO IFR LATE TONIGHT THEN SLOWLY IMPROVE FROM MID
MORNING THROUGH EARLY AFTERNOON.
* SOUTH-SOUTHEAST WINDS TURN SOUTHWEST BY MID MORNING WITH SPEEDS
INCREASING TO 10-15 KT WITH SOME GUSTS INTO THE UPPER TEENS
POSSIBLE.
* ADDITIONAL SCATTERED SHRA/TSRA ACTIVITY POSSIBLE THIS EVENING.
MDB
//DISCUSSION...UPDATED 06Z...
AN UPPER LEVEL DISTURBANCE PASSING OVERHEAD AND A SURFACE LOW TO
THE NORTHWEST CONTINUE TO INFLUENCE OUR WEATHER EARLY TONIGHT.
WAVES OF SHRA CONTINUE WITH THE BULK OF THE ACTIVITY HAVING
CLEARED TO THE EAST OF THE TERMINALS...BUT ADDITIONAL SCATTERED
SHOWERS ARE APPROACHING FROM THE WEST. THESE WILL CROSS THE AREA
OVER THE NEXT SEVERAL HOURS WITH DRY CONDITIONS BUILDING IN
BEHIND. LOWERING CIGS ARE A CONCERN WITH A LARGE AREA OF IFR TO
THE WEST. HAVE SLOWED THE ARRIVAL OF IFR AT THE TERMINALS BUT THIS
MAY NOT BE SLOW ENOUGH...THOUGH DO EXPECT IFR TO BE IN PLACE FOR
THE MORNING RUSH. CIGS WILL GRADUALLY LIFT THROUGH THE LATE
MORNING THEN LIKELY BECOME VFR EARLY/MID AFTERNOON. CIGS MAY
SCATTER SO MAY ALSO NEED TO INCLUDE LOWER CLOUD COVERAGE BY MID
AFTERNOON.
SOUTHEASTERLY WINDS ARE TRENDING SOUTHERLY AND WILL SHIFT TO THE
SOUTHWEST AFTER DAYBREAK WITH SPEEDS INCREASING SOMEWHAT BY MID
MORNING. WILL CONTINUE WITH CURRENT MENTION OF LLWS GIVEN WIND
SPEEDS AROUND 40 KT TOWARD 2000 FT WITH LIGHTER WINDS AT THE
SURFACE. WINDS OFF THE DECK WILL DECREASE OVER THE NEXT FEW HOURS.
SPEEDS WILL THEN EASE THIS AFTERNOON WITH A TENDENCY FOR A MORE
WEST-SOUTHWEST DIRECTION. SPEEDS LOOK STRONG ENOUGH TO KEEP A
LAKE BREEZE CONFINED TO THE SHORELINE. WINDS WILL FURTHER EASE
THIS EVENING AND TURN TO THE SOUTH AS A WARM FRONTAL BOUNDARY
MOVES NORTH ACROSS THE TERMINALS. THIS MAY ALSO TRIGGER SOME
SCATTERED SHRA/TSRA THIS EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN INTERMITTENT SHRA CONTINUING FOR SEVERAL MORE
HOURS.
* MEDIUM-HIGH CONFIDENCE IN CIGS LOWERING TO IFR. MEDIUM
CONFIDENCE IN TIMING...MAY NEED TO SLOW ARRIVAL DOWN. HIGH
CONFIDENCE IN CIGS IMPROVING TO VFR BUT MEDIUM CONFIDENCE IN
TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN GUST SPEEDS
MID/LATE MORNING. MAY NEED TO NUDGE THEM UP SLIGHTLY.
* MEDIUM CONFIDENCE IN SCATTERED SHRA/TSRA THIS EVENING.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE. MODERATE SOUTH WINDS.
SUNDAY...SHRA/TSRA LIKELY. MVFR POSSIBLE. STRONG/GUSTY SOUTH
WINDS.
MONDAY...SLIGHT CHANCE LINGERING SHRA EARLY. WINDS TURNING
NWLY...THEN NLY OVERNIGHT.
TUESDAY AND WEDNESDAY...VFR/WX NIL. MODERATE NELY TO ELY WINDS.
KREIN
&&
.MARINE...
253 AM CDT
WEAK LOW PRESSURE OVER WESTERN WISCONSIN EARLY THIS
MORNING WILL MOVE EAST ACROSS UPPER MICHIGAN AND WEAKEN TODAY.
FAIRLY STEADY SOUTH TO SOUTHEAST WINDS WILL DIMINISH THIS AFTERNOON
AS THE PRESSURE GRADIENT WEAKENS BEHIND THE LOW AS A WEAK HIGH MOVES
ACROSS THIS SAME AREA TONIGHT. THIS WILL LIKELY LEAD TO LIGHT
ONSHORE FLOW DEVELOPING LATER THIS AFTERNOON. A WARM FRONTAL
BOUNDARY DEVELOPS AND MOVES NORTH ACROSS THE LAKE TONIGHT ALLOWING
THE WINDS TO TREND SOUTHERLY BUT THE PRESSURE GRADIENT WILL BE WEAK
THROUGH MUCH OF SATURDAY WHICH WILL ALLOW ANOTHER LAKE
BREEZE/ONSHORE FLOW TO DEVELOP. STRONG LOW PRESSURE WILL BE
DEVELOPING ACROSS THE NORTHERN PLAINS SATURDAY AND SATURDAY NIGHT
ALLOWING THE GRADIENT TO STEADILY TIGHTEN LEADING TO A STEADIER
SOUTH TO SOUTH-SOUTHEAST WIND FOR SUNDAY. WITH MUCH WARMER AIR
SPREADING ACROSS THE LAKE GUSTS WILL BE MUTED BUT NEARSHORE AREAS
WILL SEE MIXING SPREAD OFFSHORE AND LIKELY SEE THE STRONGEST WINDS
BEFORE THE STABLE LAYER TAKES OVER FURTHER OFFSHORE. FOG WILL LIKELY
DEVELOP TONIGHT AND PERSIST ACROSS MUCH OF THE LAKE THROUGH SUNDAY
NIGHT. FOG MAY BECOME DENSE WITH MINIMAL VISIBILITY ACROSS THE OPEN
WATERS...WHILE FAR SOUTHERN AREAS WILL PROBABLY SEE BETTER
VISIBILITY AS SOUTH WINDS INCREASE LATER SATURDAY.
THE LOW PEAKS IN INTENSITY LATER SUNDAY ACROSS CENTRAL MINNESOTA
THEN WEAKENS AS IT MOVES ACROSS LAKE SUPERIOR MONDAY. A COLD FRONT
WILL EXTEND FROM THE LOW AND MOVE ACROSS THE LAKE SUNDAY NIGHT OR
MONDAY MORNING BRINGING A SHIFT TO SOUTHWEST THEN WEST WINDS INTO
MONDAY EVENING. SPEEDS WILL PICK UP AND MIXING WILL BEGIN TO DEVELOP
AS COLDER AIR SPREADS INTO THE REGION. STRONG LOW PRESSURE WILL BE
SETTLING SOUTHWARD INTO THE PLAINS KEEPING THE PRESSURE GRADIENT
TIGHT AND COMBINE WITH THE COLD ADVECTION TO BRING A PERIOD OF
FAIRLY GUSTY WEST TO NORTHWEST WINDS MONDAY NIGHT/TUESDAY. ITS STILL
A WAYS OUT FOR DETAILS BUT SPEEDS MAY PUSH 30 KT LATER MONDAY/MONDAY
NIGHT...ESPECIALLY NORTH WHERE THE BEST MIXING IS EXPECTED.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1241 AM CDT FRI MAY 15 2015
.UPDATE...
941 PM CDT
LIGHTNING STRIKES HAVE BEEN LIMITED SOUTH OF THE AREA THIS
EVENING. WHILE THE FIRST MAIN WAVE OF RAIN IS THROUGH...ADDITIONAL
SHOWERS WILL CONTINUE THIS EVENING AREA WIDE...WITH THE FOCUS
SHIFTING FARTHER SOUTH THROUGH THE NIGHT. WHILE THE THUNDER WAS
REMOVED FOR THE EVENING PERIOD...WILL HOLD ONTO THE ISOLATED
THUNDER MENTION OVERNIGHT AS BETTER LAPSE RATES ALOFT ADVECT
NORTHWARD AND RAP HANGS ONTO SOME WEAK MOST UNSTABLE CAPE. ONE
LONE CLOUD TO GROUND STRIKE OCCURRED IN CHAMPAIGN COUNTY NOT TOO
LONG AGO. AREAS SOUTH OF I-80 HOLD THE BEST CHANCE FOR AN ISOLATED
STRIKE OR TWO.
KMD
&&
.SHORT TERM...
253 PM CDT
THROUGH FRIDAY...
AN ELONGATED NEGATIVELY-TILTED UPPER TROUGH...EXTENDING FROM THE RED
RIVER VALLEY OF THE NORTH TO SOUTHERN ILLINOIS THIS AFTERNOON...WILL
CONTINUE ITS ADVANCE NORTHEAST TONIGHT. WHILE THERE ARE MULTIPLE
EMBEDDED SHORT WAVE IMPULSES WITHIN THIS...THE MOST PRONOUNCED FOR
OUR AREA IS A CIRCULATION CENTER NEAR THE IA/MO/IL BORDER. FOCUSED
ASCENT JUST AHEAD OF THIS IS IN TANDEM WITH A 40 KT LOW-LEVEL JET
PER ILX AND LSX VWP DATA...AND REGIONAL RADAR MOSAIC INDICATES
SHOWERS INCREASING IN COVERAGE AND INTENSITY ACROSS WESTERN ILLINOIS
AND EASTERN MISSOURI AS OF 230 PM.
THIS FAVORED AREA OF FORCING AND SHOWERS WILL EXPAND INTO THE
ILLINOIS FORECAST AREA BY EARLY EVENING. HAVE GONE AS DETERMINISTIC
AS COULD WITH HOURLY POPS...LEVERAGING SOME ON CONVECTIVE ALLOWING
MODELS/ENSEMBLES AND MORE SO OBSERVATIONAL TRENDS. DEEPER PWATS
AROUND 1.4 INCHES AND SLIGHTLY BETTER LAPSE RATES ALOFT IMMEDIATELY
AHEAD OF THE CIRCULATION SUPPORT CHANCES FOR ISOLATED EMBEDDED
THUNDER THIS EVENING. TOO LITTLE OF RECOVERY TIME FOR LAPSE RATES
SHOULD STUNT ANY SEVERE WEATHER THREAT.
THE MAIN CHANGE WITH THE FORECAST FOR TONIGHT WAS TO DIMINISH...AND
IN MANY PLACES END... POPS EARLIER OVERNIGHT FROM SOUTHWEST TO
NORTHEAST...BASED HEAVILY ON UPSTREAM OBSERVATIONAL TRENDS WITH HOUR-
TO-HOUR RUNS OF THE RAP/HRRR SEEM TO BE CATCHING UP ON. EXPECT THE
ILLINOIS FORECAST AREA TO HAVE THE LONGEST TIME WITH SHOWERS
/4-6 HOURS/ AND SOME PLACES TO FINISH AROUND ONE HALF INCH...WHILE
TAPERING TO NEAR OR UNDER ONE QUARTER OF AN INCH INTO NORTHWEST
INDIANA.
SIZABLE PRESSURE FALLS AT THE SURFACE WILL KEEP UP SOUTHEAST WINDS
TONIGHT AND TEMPERATURES REALLY SHOULD ONLY DROP BY WET BULB
COOLING. THE WINDS SHOULD ALSO PREVENT FOG FROM BEING MUCH OF A
PROBLEM ONCE THE RAIN ENDS...AT LEAST OVER LAND. LOWS ARE EXPECTED
IN THE MID-UPPER 50S AREAWIDE.
DURING THE DAY FRIDAY FORCING IS FAIRLY MINIMAL FOR RAIN...SO
CONTINUE POPS LOW OR NON-MENTIONABLE. A SYNOPTIC BOUNDARY STARTS TO
TAKE SHAPE FROM EAST-TO-WEST ACROSS CENTRAL ILLINOIS AND
CONVERGENCE/MOISTURE TRANSPORT INTO AND ALONG THIS WILL START TO
GRADUALLY STRENGTHEN DURING THE AFTERNOON. THIS IS WHERE HAVE KEPT
THE POPS. CONFIDENCE IS SOMEWHAT SHAKE ON HOW QUICKLY CLOUDS
SCATTER...BUT HAVE HIGHS RECOVERING FROM MID 70S TO LOWER 80S FROM
NORTH-TO-SOUTH.
MTF
&&
.LONG TERM...
253 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
UPPER LEVEL RIDGING WILL TRANSLATE ACROSS NORTHERN ILLINOIS FRIDAY
NIGHT INTO EARLY SATURDAY HOWEVER BOTH THE NAM AND GFS ADVERTISE
A SUBTLE SHORTWAVE EMBEDDED WITHIN THE UPPER RIDGE LIFTING ACROSS
THE AREA FRIDAY NIGHT. SOUNDINGS SHOW MODEST INSTABILITY WILL BE
IN PLACE OVERNIGHT AND ANY LIFT ASSOCIATED WITH THE SHORTWAVE MAY
BE ABLE TO TRIGGER A FEW THUNDERSTORMS. FORCING IS OTHERWISE
FAIRLY WEAK SO THINK COVERAGE SHOULD BE FAIRLY SCATTERED.
MEANWHILE...JET STREAM ROUNDING THE BASE OF THE LONGWAVE TROUGH
CENTERED OVER THE INTERMOUNTAIN WEST WILL LIFT INTO THE CENTRAL
PLAINS SATURDAY WITH SURFACE LOW DEVELOPING OVER WESTERN KS/NE
SATURDAY AFTERNOON. THE MIDWEST WILL ALREADY BE UNDER A MOIST
AIRMASS WITH WIDE OPEN GULF...BUT THIS NEXT WAVE WILL FURTHER
INCREASE MOISTURE WITH PWATS PUSHING 1.5-1.6 INCHES BY LATER IN THE
DAY SATURDAY. HIGHS IN THE LOW TO MID 80S AND SURFACE DEW POINTS IN
THE MID 60S WILL RESULT IN MODERATE INSTABILITY ACROSS THE
AREA...WEAKLY CAPPED OR UNCAPPED PER FORECAST SOUNDINGS. MOST
MODELS INDICATE WIDESPREAD CONVECTIVE ACTIVITY IN THE WARM
SECTOR ACROSS THE MIDWEST AND MISSISSIPPI RIVER VALLEY WHILE THE
MOST FOCUSED FORCING REMAINS WEST OF THE MISSISSIPPI RIVER. GIVEN
THE INSTABILITY AND WEAK FORCING...WILL BE HARD TO PIN DOWN MOST
FAVORED AREAS FOR THUNDERSTORM ACTIVITY BUT GENERALLY EXPECT
SCATTERED UNORGANIZED ACTIVITY WHICH MAY END UP BEING DIURNALLY
FAVORED.
A LOW LEVEL JET FORMS SATURDAY NIGHT FOCUSED ACROSS THE MID-
MISSOURI VALLEY AND SHIFTING EAST ACROSS IOWA DURING THE
OVERNIGHT HOURS. BEST PRECIP CHANCES WILL BE ACROSS THESE AREAS
SATURDAY NIGHT WHILE MODELS CONTINUE TO PRODUCE WIDELY SCATTERED
UNORGANIZED ACTIVITY ACROSS THE LOCAL FORECAST AREA GIVEN THE
CONTINUED INSTABILITY.
SUNDAY CONTINUES TO APPEAR AT LEAST FAVORABLE FOR SEVERE WEATHER
IN THE AREA. EARLY DAY SOUNDINGS SHOW A CAP IN PLACE WHICH
SHOULD HELP ANY FESTERING NOCTURNAL CONVECTION MOVING IN FROM OUR
WEST DISSIPATE...AND FOR INSTABILITY TO BUILD THROUGH THE MORNING
AND EARLY AFTERNOON. MID/HIGH LEVEL CLOUD COVER MAY IMPEDE
INSOLATION SOME...HOWEVER GUIDANCE CONTINUES TO ADVERTISE A
CORRIDOR OF 1000+ J/KG MLCAPE AHEAD OF THE COLD FRONT MOVING
ACROSS NORTHERN ILLINOIS LATE AFTERNOON INTO THE EVENING. IN
ADDITION...NEGATIVELY TILTED TROUGH IS PROGGED TO LIFT INTO THE
UPPER MIDWEST SUNDAY WHICH SHOULD HELP ERODE THE CAP...AND THE JET
STREAM ADVECTS OVERHEAD RESULTING IN INCREASING DEEP LAYER SHEAR.
LATEST GFS ADVERTISES 35-45 KT OF FAIRLY UNIDIRECTIONAL 0-6KM
SHEAR MOVING OVER THE AREA WHICH WILL BE SUFFICIENT TO SUPPORT AN
ORGANIZED SEVERE WEATHER THREAT SHOULD THE INSTABILITY AND FORCING
MATERIALIZE AS EXPECTED.
THE COLD FRONT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWEST
INDIANA EARLY ON MONDAY WITH INITIALLY BREEZY NORTHWEST/NORTH WIND
BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. COLD ADVECTION AND WINDS TURNING OFF OF LAKE MICHIGAN
WILL RESULT IN TEMPERATURES RETURNING TO COLDER THAN NORMAL
LEVELS...ESPECIALLY TUESDAY WHERE HIGHS MAY ONLY TOP OUT IN THE
50S...THEN GRADUALLY MODERATING AS WE HEAD THROUGH MIDWEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* INTERMITTENT SHRA CONTINUES THROUGH THE EARLY OVERNIGHT HOURS.
* CIGS LOWER TO IFR LATE TONIGHT THEN SLOWLY IMPROVE FROM MID
MORNING THROUGH EARLY AFTERNOON.
* SOUTH-SOUTHEAST WINDS TURN SOUTHWEST BY MID MORNING WITH SPEEDS
INCREASING TO 10-15 KT WITH SOME GUSTS INTO THE UPPER TEENS
POSSIBLE.
* ADDITIONAL SCATTERED SHRA/TSRA ACTIVITY POSSIBLE THIS EVENING.
MDB
//DISCUSSION...UPDATED 06Z...
AN UPPER LEVEL DISTURBANCE PASSING OVERHEAD AND A SURFACE LOW TO
THE NORTHWEST CONTINUE TO INFLUENCE OUR WEATHER EARLY TONIGHT.
WAVES OF SHRA CONTINUE WITH THE BULK OF THE ACTIVITY HAVING
CLEARED TO THE EAST OF THE TERMINALS...BUT ADDITIONAL SCATTERED
SHOWERS ARE APPROACHING FROM THE WEST. THESE WILL CROSS THE AREA
OVER THE NEXT SEVERAL HOURS WITH DRY CONDITIONS BUILDING IN
BEHIND. LOWERING CIGS ARE A CONCERN WITH A LARGE AREA OF IFR TO
THE WEST. HAVE SLOWED THE ARRIVAL OF IFR AT THE TERMINALS BUT THIS
MAY NOT BE SLOW ENOUGH...THOUGH DO EXPECT IFR TO BE IN PLACE FOR
THE MORNING RUSH. CIGS WILL GRADUALLY LIFT THROUGH THE LATE
MORNING THEN LIKELY BECOME VFR EARLY/MID AFTERNOON. CIGS MAY
SCATTER SO MAY ALSO NEED TO INCLUDE LOWER CLOUD COVERAGE BY MID
AFTERNOON.
SOUTHEASTERLY WINDS ARE TRENDING SOUTHERLY AND WILL SHIFT TO THE
SOUTHWEST AFTER DAYBREAK WITH SPEEDS INCREASING SOMEWHAT BY MID
MORNING. WILL CONTINUE WITH CURRENT MENTION OF LLWS GIVEN WIND
SPEEDS AROUND 40 KT TOWARD 2000 FT WITH LIGHTER WINDS AT THE
SURFACE. WINDS OFF THE DECK WILL DECREASE OVER THE NEXT FEW HOURS.
SPEEDS WILL THEN EASE THIS AFTERNOON WITH A TENDENCY FOR A MORE
WEST-SOUTHWEST DIRECTION. SPEEDS LOOK STRONG ENOUGH TO KEEP A
LAKE BREEZE CONFINED TO THE SHORELINE. WINDS WILL FURTHER EASE
THIS EVENING AND TURN TO THE SOUTH AS A WARM FRONTAL BOUNDARY
MOVES NORTH ACROSS THE TERMINALS. THIS MAY ALSO TRIGGER SOME
SCATTERED SHRA/TSRA THIS EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN INTERMITTENT SHRA CONTINUING FOR SEVERAL MORE
HOURS.
* MEDIUM-HIGH CONFIDENCE IN CIGS LOWERING TO IFR. MEDIUM
CONFIDENCE IN TIMING...MAY NEED TO SLOW ARRIVAL DOWN. HIGH
CONFIDENCE IN CIGS IMPROVING TO VFR BUT MEDIUM CONFIDENCE IN
TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN GUST SPEEDS
MID/LATE MORNING. MAY NEED TO NUDGE THEM UP SLIGHTLY.
* MEDIUM CONFIDENCE IN SCATTERED SHRA/TSRA THIS EVENING.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE. MODERATE SOUTH WINDS.
SUNDAY...SHRA/TSRA LIKELY. MVFR POSSIBLE. STRONG/GUSTY SOUTH
WINDS.
MONDAY...SLIGHT CHANCE LINGERING SHRA EARLY. WINDS TURNING
NWLY...THEN NLY OVERNIGHT.
TUESDAY AND WEDNESDAY...VFR/WX NIL. MODERATE NELY TO ELY WINDS.
KREIN
&&
.MARINE...
253 PM CDT
HIGH PRESSURE IS CENTERED EAST OF LAKE MICHIGAN TODAY AND WILL
MOVE TO THE MID ATLANTIC COAST OVERNIGHT. AS THE HIGH DRIFTS
EAST...SOUTHEAST WINDS WILL FRESHEN UP ACROSS LAKE MICHIGAN
TONIGHT. A WEAK LOW WILL TRAVERSE THE REGION FRIDAY LIFTING A WARM
FRONT NORTH ACROSS THE LAKE...THEN A SECOND STRONGER LOW WILL TAKE
SHAPE OVER THE PLAINS FRIDAY AND LIFT INTO THE UPPER MIDWEST BY
SUNDAY BRINGING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
IN ADDITION...MOISTURE WILL INCREASE ACROSS THE REGION AND STABLE
CONDITIONS OVER THE LAKE WILL BE FAVORABLE FOR FOG TO DEVELOP FOR
MUCH OF THE WEEKEND. A COLD FRONT WILL SWEEP ACROSS LAKE MICHIGAN
EARLY MONDAY AND TURNING WINDS WESTERLY AND SHOULD MARK AND END
FOR PRECIP AND FOG CHANCES.
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/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1153 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 906 PM CDT THU MAY 14 2015
SCATTERED SHOWERS CONTINUE TO MOVE ACROSS THE AREA, MAINLY NORTH
OF I-70. ALREADY MADE ONE ADJUSTMENT TO WX GRIDS TO REMOVE MENTION
OF THUNDER...BUT WILL BE MAKING ANOTHER ADJUSTMENT TO POPS FOR
REMAINDER OF THE NIGHT. HRRR MODEL CONTINUES TO DEVELOP SCATTERED
PCPN JUST TO THE WEST OF THE AREA AND MOVE IT INTO THE CWA.
THEREFORE WILL KEEP SCATTERED SHOWERS MENTIONED IN FORECAST GRIDS.
REMAINDER OF FORECAST LOOK OK BUT WILL SENDING AN UPDATE SHORTLY.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 206 PM CDT THU MAY 14 2015
SHOWERS THUS FAR HAVE CONTINUED TO BATTLE A VERY DRY AIRMASS OVER
CENTRAL ILLINOIS. HOWEVER...A MORE ROBUST AREA OF SHOWERS ASSOCIATED
WITH THE UPPER LOW CURRENTLY TRACKING ACROSS NORTHERN MISSOURI WILL
BE ARRIVING IN THE ILLINOIS RIVER VALLEY BY MID AFTERNOON. THE HRRR
MODEL...WHICH HAS BEEN DOING A DECENT JOB THUS FAR...SHOWS SOME
ADDITIONAL DEVELOPMENT WEST OF I-55 LATE AFTERNOON INTO THE
EVENING... AND HAVE CONCENTRATED THE HIGHER POP`S IN THESE AREAS.
HIGHER-RESOLUTION MODELS SUCH AS THE HRRR AND NMM/ARW AGREE WITH THE
NAM SOLUTION OF THE EVOLUTION OF A MORE EAST-WEST CONFIGURATION OF
SHOWERS ROUGHLY CENTERED ALONG I-72 BY MIDNIGHT. THUNDER UPSTREAM IN
MISSOURI HAS BEEN MINIMAL THUS FAR...AND INSTABILITY PARAMETERS OFF
THE NAM...RAP AND ARW SUGGEST ANY THUNDER IN OUR AREA WOULD BE MOST
LIKELY ALONG AND WEST OF I-55 TONIGHT.
NOT MUCH OF A DROPOFF EXPECTED IN TEMPERATURES TONIGHT...GENERALLY
REMAINING STEADY IN THE LOWER 60S.
.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 206 PM CDT THU MAY 14 2015
IN THE WAKE OF THE WAVE MOVING ACROSS THE MIDWEST TODAY...HEIGHTS
BUILD BRIEFLY AHEAD OF NEXT WEAKER WAVE MOVING NORTHEAST AROUND WEST
COAST CLOSED LOW. HOWEVER, MODELS ARE CONSISTENT IN REDEVELOPING THE
WARM FRONT OVER CENTRAL ILLINOIS FRIDAY AND WITH THE WEAKER WAVE
APPROACHING FRIDAY AFTERNOON, THUNDERSTORMS WILL LIKELY DEVELOP.
WILL NEED TO RETAIN AT LEAST LOW POPS DESPITE THE RIDGING.
INSTABILITY OF 1500-2000 J/KG WILL BE POSSIBLE ALONG AND TO THE
SOUTH OF THE FRONT IN AREAS THAT SEE A LITTLE SUN THOUGH SHEAR WILL
BE QUITE LIMITED.
AS SOUTHERLY FLOW BECOMES ESTABLISHED...DEW POINTS WILL RESPOND BY
CLIMBING INTO THE 60S FOR FRIDAY AFTERNOON AND THE WEEKEND. AS THE
WEST COAST ENERGY BEGINS TO PULL NORTHEAST TOWARD THE GREAT LAKES,
WAVES WILL EJECT FROM THE SYSTEM AND PERIODICALLY CONTRIBUTE TO LIFT
ALONG ANY CONVECTIVELY ENHANCED BOUNDARIES LYING ACROSS THE AREA.
THIS WILL MAKE TIMING OF PRECIPITATION DIFFICULT UNTIL THE MAIN
ENERGY PASSES NORTHWEST OF ILLINOIS ON SUNDAY. WILL HAVE TO
GENERALLY BROADBRUSH GIVEN THE POTENTIAL INSTABILITY (1500-2500
J/KG) IN PLACE. 0-6KM SHEAR IS FORECAST TO REMAIN BELOW 20 KTS
THROUGH SATURDAY EVENING, SO WIDESPREAD SEVERE WEATHER IS NOT
EXPECTED THOUGH GIVEN THE HIGH PRECIPITABLE WATER WOULD NOT BE
SURPRISED TO SEE SOME WET MICROBURST ACTIVITY PRODUCING GUSTY WINDS
AT TIMES SATURDAY.
THE MISSING INGREDIENT (DEEP SHEAR) JOINS THE ENVIRONMENT ON SUNDAY
AS THE MAIN WAVE PASSES NORTHWEST OF ILLINOIS. 0-6KM SHEAR IS
EXPECTED TO SURPASS 40 KTS BY SUNDAY EVENING. THERE DOES SEEM TO
BE POTENTIAL FOR ROTATING UPDRAFTS GIVEN GFS FORECASTED 0-1KM
HELECITY VALUES OF 125-150 M2/S2 AND LCL HEIGHTS BELOW 900 MB.
STORM MOTION ALSO SUGGESTS THAT WINDS MAY BE A THREAT WITH
FORECASTED STORM MOTION AROUND 40 KTS. THREAT WILL LIKELY INCREASE
FROM SOUTHEAST TO NORTHWEST ACROSS FORECAST AREA DUE TO PROXIMITY
OF THE WAVE.
ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH SUNDAY NIGHT AND
MUCH COOLER TEMPERATURES ARE EXPECTED FOR THE BEGINNING OF THE WORK
WEEK. STILL SOME SPREAD IN LATEST MODELS WITH REGARDS TO HOW MUCH
COLD AIR WILL PENETRATE THE MIDWEST BEHIND FRONT WITH THE ECMWF
COOLER THAN GFS/DGEX. HOWEVER, 12Z GFS IS TRENDING TOWARD THIS
COOLER SOLUTION. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS FOR
NOW AND KEEP AT LEAST SOME LOW POPS IN FOR WED THROUGH THU.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1153 PM CDT THU MAY 14 2015
WIDELY SCATTERED SHOWERS CONTINUE ACROSS THE AREA SO WILL BE
KEEPING VCSH AT ALL TAF SITES THROUGH THE OVERNIGHT HOURS. SHORT
TERM MODELS CONTINUE TO SHOW LOWER/MVFR CIGS ARRIVING DURING THE
MORNING HOURS SO WILL BE KEEPING THOSE LEVEL CIGS IN TAFS DURING
THE MORNING WITH PIA AT 2.5KFT...BMI AT 2KFT AND SPI/DEC/CMI AT
3KFT. THINKING IS THAT DURING THE EARLY AFTERNOON SKIES WILL
BECOME SCATTERED AT ALL SITES. THEN A WEAK BOUNDARY ACROSS THE
MIDDLE OF THE STATE COULD BECOME ACTIVE WITH SCATTERED
THUNDERSTORMS SO WILL HAVE VCTS AT SPI/DEC/CMI. THINK THESE WILL
REMAIN SOUTH OF PIA AND BMI SO WILL JUST HAVE INCREASED VFR CLOUDS
AT 4KFT FOR THE EVENING. WINDS WILL BE SOUTHEAST OVERNIGHT AND
THEN BECOME SOUTHWEST DURING THE MORNING AND THEN SOUTHERLY DURING
THE EVENING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AUTEN
SHORT TERM...GEELHART
LONG TERM...BARKER
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
247 AM EDT FRI MAY 15 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 342 PM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1006 PM EDT THU MAY 14 2015
RADAR LATE THIS EVENING SHOWS A WAVE OF SHOWERS OVER NORTHWEST
CENTRAL INDIANA PUSHING NORTHEAST. MEANWHILE THE REST OF CENTRAL
INDIANA WAS PRECIP FREE...AS WAS THE FLOW UPSTREAM. THUS HAVE
DROPPED POPS OFF FOR THE NEXT FEW HOURS ACROSS MUCH OF THE FORECAST
AREA AS THE WAVE TO THE NORTHWEST BRUSHES BY OUR FORECAST AREA.
HAVE RAMPED POPS BACK UP TO THE LOW CHC CATEGORY AFT 06-07Z..AS
THE HRRR AND GFS SUGGEST SOME SATURATION ACROSS CENTRAL INDIANA IN
ASSOCIATION WITH THE PASSING WAVE. CONFIDENCE IS LOW WIT THIS
FEATURE ANY ANY PRECIP AMOUNT SHOULD BE QUITE LIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 342 PM EDT THU MAY 14 2015
AS PREVIOUSLY MENTIONED IN THE ABOVE NEAR TERM DISCUSSION...THIS
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING. EVENTUALLY
SOME RIDGING ALOFT WILL REESTABLISH ITSELF. THEN THERE IS GOOD
POTENTIAL FOR THE REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY
AFTERNOON WITHIN THIS INCREASINGLY MOIST...WARM...AND UNSTABLE
AIRMASS ACROSS CENTRAL INDIANA. HAVE MAINTAINED SCATTERED POPS FOR
THIS TIME PERIOD AS WELL. SEVERE STORMS ARE NOT ANTICIPATED BUT IF
AND WHEN STRONGER STORMS DEVELOP THEY WILL HAVE THE POTENTIAL TO
PRODUCE HAIL...VERY HEAVY RAINFALL (PER FORECAST PWATS) IN
ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING.
AS FOR THE REST OF THIS PERIOD CENTRAL INDIANA CAN EXPECT TO SEE
MORE OF THE SAME WITH WARM HUMID CONDITIONS AS GULF MOISTURE
LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT THIS WEEKEND
WILL BE LARGELY DEPENDENT ON AVAILABLE INSTABILITY. CONSIDERING
LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES
NOT WARRANT ANY HIGHER THAN 40 TO 70 POPS AT THIS POINT IN TIME.
ALSO...THIS WEEKEND WILL NOT BE A TOTAL WASHOUT BUT WILL CONTINUE TO
CARRY EITHER SCATTERED OR LIKELY SHOWERS AND THUNDERSTORMS FOR
ON/OFF PERIOD THROUGH THE WEEKEND.
IN TERMS OF TEMPERATURES...GUIDANCE IS IN AGREEMENT SO DID NOT
NEED TO MAKE MANY CHANGES AND GENERALLY USED A BLEND FOR
SUMMERTIME LIKE HIGHS IN THE LOW 80S. LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 247 AM EDT FRI MAY 15 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
A COLD FRONT WILL BE EXITING THE AREA ON MONDAY SO KEPT SOME LOW
POPS DURING THE DAY. MUCH COLDER AIR WILL THEN BUILD IN FOR THE
REMAINDER OF THE LONG TERM WITH TEMPERATURES REMAINING BELOW AVERAGE
THROUGH THE PERIOD.
UPPER FLOW WILL BECOME MORE ZONAL AND SOME MODELS HINT AT UPPER
WAVES GENERATING LOW CHANCES FOR RAIN MID WEEK. HOWEVER CONFIDENCE
IN TIMING OF THESE WAVES AND IF THEY WILL HAVE ENOUGH MOISTURE FOR
RAIN IS LOW...SO REMOVED ANY POPS AND WENT DRY MON. NIGHT-THURSDAY.
&&
.AVIATION /DISCUSSION FOR THE 15/06Z TAFS/...
ISSUED AT 1245 AM EDT FRI MAY 15 2015
VFR THROUGH MUCH OF THE PERIOD OUTSIDE OF ANY POTENTIAL SPOTTY
SHOWERS OVERNIGHT AND ANY THUNDERSTORMS FRIDAY.
CLOUD COVER GENERALLY AROUND 6-8KFT OVERNIGHT BUT GRADUALLY LOWERING
LATE AND INTO FRIDAY. NO VISIBILITY ISSUES ANTICIPATED OUTSIDE OF
PRECIPITATION.
WINDS WILL BE 10KT OR LESS OUT OF THE SOUTHEAST OVERNIGHT...BECOMING
10 PLUS KNOTS TOMORROW MID MORNING GUSTING AS HIGH AS AROUND
20KT...OUT OF THE SOUTHWEST.
THUNDER CANNOT COMPLETELY BE RULED OUT FRIDAY AFTERNOON...BUT WILL
BE FAR TOO SPOTTY AND UNCERTAIN FOR INCLUSION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...PUMA
SHORT TERM...SMF
LONG TERM...50
AVIATION...NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1245 AM EDT FRI MAY 15 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 342 PM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1006 PM EDT THU MAY 14 2015
RADAR LATE THIS EVENING SHOWS A WAVE OF SHOWERS OVER NORTHWEST
CENTRAL INDIANA PUSHING NORTHEAST. MEANWHILE THE REST OF CENTRAL
INDIANA WAS PRECIP FREE...AS WAS THE FLOW UPSTREAM. THUS HAVE
DROPPED POPS OFF FOR THE NEXT FEW HOURS ACROSS MUCH OF THE
FORECAST AREA AS THE WAVE TO THE NORTHWEST BRUSHES BY OUR FORECAST AREA.
HAVE RAMPED POPS BACK UP TO THE LOW CHC CATEGORY AFT 06-07Z..AS
THE HRRR AND GFS SUGGEST SOME SATURATION ACROSS CENTRAL INDIANA IN
ASSOCIATION WITH THE PASSING WAVE. CONFIDENCE IS LOW WIT THIS
FEATURE ANY ANY PRECIP AMOUNT SHOULD BE QUITE LIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 342 PM EDT THU MAY 14 2015
AS PREVIOUSLY MENTIONED IN THE ABOVE NEAR TERM DISCUSSION...THIS
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING. EVENTUALLY
SOME RIDGING ALOFT WILL REESTABLISH ITSELF. THEN THERE IS GOOD
POTENTIAL FOR THE REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY
AFTERNOON WITHIN THIS INCREASINGLY MOIST...WARM...AND UNSTABLE
AIRMASS ACROSS CENTRAL INDIANA. HAVE MAINTAINED SCATTERED POPS FOR
THIS TIME PERIOD AS WELL. SEVERE STORMS ARE NOT ANTICIPATED BUT IF
AND WHEN STRONGER STORMS DEVELOP THEY WILL HAVE THE POTENTIAL TO
PRODUCE HAIL...VERY HEAVY RAINFALL (PER FORECAST PWATS) IN
ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING.
AS FOR THE REST OF THIS PERIOD CENTRAL INDIANA CAN EXPECT TO SEE
MORE OF THE SAME WITH WARM HUMID CONDITIONS AS GULF MOISTURE
LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT THIS WEEKEND
WILL BE LARGELY DEPENDENT ON AVAILABLE INSTABILITY. CONSIDERING
LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES
NOT WARRANT ANY HIGHER THAN 40 TO 70 POPS AT THIS POINT IN TIME.
ALSO...THIS WEEKEND WILL NOT BE A TOTAL WASHOUT BUT WILL CONTINUE TO
CARRY EITHER SCATTERED OR LIKELY SHOWERS AND THUNDERSTORMS FOR
ON/OFF PERIOD THROUGH THE WEEKEND.
IN TERMS OF TEMPERATURES...GUIDANCE IS IN AGREEMENT SO DID NOT
NEED TO MAKE MANY CHANGES AND GENERALLY USED A BLEND FOR
SUMMERTIME LIKE HIGHS IN THE LOW 80S. LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 205 PM EDT THU MAY 14 2015
ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO SUGGEST A WARM AND
UNSETTLED START TO THE EXTENDED.
THE DETERMINISTIC 12Z GFS AND 00Z ECMWF ALONG WITH THE ENSEMBLE
MEANS ARE IN VERY GOOD AGREEMENT REGARDING THE SYNOPTIC PATTERN FOR
THE EXTENDED. THEY LIFT AN UPPER LOW...CURRENTLY OFF THE CALIFORNIA
COAST...NORTHEAST TO ONTARIO ON MONDAY. THIS WILL ALLOW A FRONTAL
SYSTEM TO SWEEP SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY. THE
FRONT WILL INTERACT WITH WARM...MOIST AND UNSTABLE AIR AND TRIGGER
SCATTERED TO NUMEROUS THUNDERSTORMS SUNDAY NIGHT AND MONDAY...BEFORE
COOLER AND DRY WEATHER RETURN UNDER THE INFLUENCE OF STRONG HIGH
PRESSURE BUILDS IN FROM THE WEST. REGIONAL BLEND POPS HANDLE THIS
WELL WITH GOOD CHANCE POPS SUNDAY NIGHT INTO MONDAY AND DRY BY
MONDAY NIGHT. TO WRAP UP THE EXTENDED...A WEAK SOUTHERN SYSTEM COULD
BRING A FEW SHOWERS OR STORMS TO THE AREA BY NEXT THURSDAY.
TEMPERATURES SHOULD START OFF ABOVE NORMAL AHEAD OF THE COLD FRONT
AND THEN FALL TO BELOW NORMAL BEHIND THE FRONT WITH HIGHS ONLY IN
THE 60S LOOKING GOOD BY TUESDAY PER THE REGIONAL BLEND.
&&
.AVIATION /DISCUSSION FOR THE 15/06Z TAFS/...
ISSUED AT 1245 AM EDT FRI MAY 15 2015
VFR THROUGH MUCH OF THE PERIOD OUTSIDE OF ANY POTENTIAL SPOTTY
SHOWERS OVERNIGHT AND ANY THUNDERSTORMS FRIDAY.
CLOUD COVER GENERALLY AROUND 6-8KFT OVERNIGHT BUT GRADUALLY LOWERING
LATE AND INTO FRIDAY. NO VISIBILITY ISSUES ANTICIPATED OUTSIDE OF
PRECIPITATION.
WINDS WILL BE 10KT OR LESS OUT OF THE SOUTHEAST OVERNIGHT...BECOMING
10 PLUS KNOTS TOMORROW MID MORNING GUSTING AS HIGH AS AROUND
20KT...OUT OF THE SOUTHWEST.
THUNDER CANNOT COMPLETELY BE RULED OUT FRIDAY AFTERNOON...BUT WILL
BE FAR TOO SPOTTY AND UNCERTAIN FOR INCLUSION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...PUMA
SHORT TERM...SMF
LONG TERM...MK
AVIATION...NIELD
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FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
359 AM CDT FRI MAY 15 2015
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/06Z
ISSUED AT 1205 AM CDT FRI MAY 15 2015
DENSE FOG WILL CONTINUE TO PROVIDE LIFR CIGS AND VIS THROUGHOUT
THE OVERNIGHT HOURS. FOD/MCW/ALO LIKELY WILL SEE THE WORST
FOG/STRATUS CONDITIONS BUT CANNOT RULE OUT DSM RECEIVING SOME
PERIODIC ONE HALF MILE VIS OVERNIGHT. CONDITIONS IMPROVE BY
SUNRISE FRIDAY MORNING...BUT MVFR STRATUS DECK REMAINS THROUGH
THE AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-
DALLAS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-
HARDIN-HUMBOLDT-JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-
TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS TOPEKA KS
359 AM CDT Fri May 15 2015
.SHORT TERM...(Today and Tonight)
Issued at 328 AM CDT FRI MAY 15 2015
A broad upper level low was slowly pushing east across southern CA
into southwest AZ. A minor lead upper level trough was lifting
northeast across west TX into western OK. This trough was providing
ascent for a complex of thunderstorms to develop across southwest OK
and west central TX early this morning. This lead upper level trough
will lift northeast into northeast OK and southeast KS later this
morning.
A lee surface trough was deepening across the central and southern
high plains. Southerly 850mb winds were advecting deeper moisture
northward across central and west central KS. The isentropic lift
was deep enough for elevated storms to develop across north central
KS. These storms were lifting north-northeast and may develop
eastward into the western counties of the CWA through the mid
morning hours. The stronger storms may produce small hail.
The GFS, RAP and WRF models show the minor wave over west central
TX/southwest OK lifting northeast and providing enough ascent along
with the deeper moisture return for scattered showers and
thunderstorms to develop across the southern counties of the CWA
during the late morning hours, and spreading northeast across east
central and northeast KS during the early afternoon hours. However
the NAM12 and HRRR show most of the the thunderstorms remaining
across the western and northern counties of the CWA this morning. I
went with chance pops across the western and southern counties this
morning with chance pops across the northeast counties this
afternoon. The vertical wind shear Today looks rather weak with only
20 to 30 KTS of SFC to 6KM effective shear across the CWA. Several
numerical models show 1500-2000 J/KG of MLCAPE developing across the
CWA, thus some of the thunderstorms this afternoon across the
northern half of the CWA may be strong to marginally severe this
afternoon. The primary hazards would be penny to quarter hail and 50
to 60 MPH wind gusts. Highs Today will range from the upper 70s to
lower 80s with mostly cloudy skies.
Tonight, the amplified upper level low will move east across UT and
the four corners region. A strong mid level jet max will move
northeast across NM into eastern CO. The minor H5 trough across
southeast KS and southwest MO this afternoon will move northeast
across central MO. The intense isentropic lift will develop
northward across the northern plains and upper Midwest. The CWA will
remain dry through most of the night. Stronger ascent across western
KS will cause elevated thunderstorms to develop late tonight. Some
of these thunderstorms may move into the western counties of the CWA
before day break. These elevated storms may be strong to severe with
the primary hazard being large hail. Overnight lows will only drop
into the mid 60s.
.LONG TERM...(Saturday through Thursday)
Issued at 328 AM CDT FRI MAY 15 2015
Forecast focus remains on impact of intense upper system that will
emerge into the Plains Saturday into Saturday night.
All models appear to be converging on the most likely scenario on
Saturday which is that severe thunderstorms will develop near and
east of a dryline from Dodge City north toward Goodland after 20z
Saturday. Storms will quickly intensify and race NE at 50 to 60
mph which could bring them into parts of central Kansas by 6pm to
7pm Saturday. If sufficient buoyancy/instability is present...low level
shear and deep shear of 20-30kts and 50-60kts respectively would
provide an environment capable of supporting all manner of hazards
with the storms.
The wild card in this forecast remains how much
morning elevated convection will develop across OK into KS. We
continue to see a signal from various models that some convection
will develop Saturday morning within the weakly capped warm
sector. This is plausible since forcing will increase in advance
of the upper trough so we could see some impact on destabilization
across parts of the area through midday if this occurs. This makes
the scenario on Saturday difficult to pin down at this point with
regard to magnitude of the risk. In any case...forcing...shear
profiles and potential instability suggest this has the potential
to be a high impact event for parts of the area Saturday evening
and will highlight that everyone needs to monitor this especially
given all of the outdoor activities this weekend.
The dry slot will work into the area Sunday with gusty southwest
winds and warm temps. Instability axis should shift east of the
area so will keep conds dry on Sunday pm. The cold front will
sweep through the area Sunday night bringing much cooler and drier
air into the area for Monday and Tues. Only a brief break before
the next wave will move into the region with more rain expected
for later Tues into early Thurs. Trends suggest that the
severe risk with this system should stay south of the area so look
for another widespread rain with isolated thunder with this system.
&&
.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1122 PM CDT THU MAY 14 2015
Mostly clear skies and light winds have led to near saturation
across the area by 11 PM. However, winds should increase and
higher clouds should thicken decreasing chances for dense fog
overnight. Can`t rule out the possibility for showers or
thunderstorms developing later tonight into the morning hours.
However, chances are low enough that have not included them in
TAF. Southerly winds will pick up during the day with gusts in the
afternoon. Another low chance of thunderstorms is possible this
evening.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1157 PM CDT THU MAY 14 2015
.UPDATE...
UPDATED AVIATION SECTION FOR 06Z TAF ISSUANCE
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 254 PM CDT THU MAY 14 2015
ALTHOUGH MID-LEVEL REGION OF THE RIDGE WEAKENED FURTHER EAST THAN
ANTICIPATED IN THE WAKE OF THE EJECTING SHORTWAVE TROUGH TO THE
NORTH AND NORTHEAST...SUBSIDENCE SHOULD BUILD BACK IN THIS
EVENING WITH A SMALLER AMPLITUDE RIDGE ALOFT. THIS SUBSIDENCE WILL
BE SHORT LIVED AS THE NEXT SHORT WAVE ROTATING OUT OF THE ROCKIES
MOVES INTO THE WFO PAH FORECAST AREA BY FRIDAY MORNING. ATTEMPTED
TO DEPICT THE MINIMA ON POPS AND WEATHER IN THE GRIDS THIS
EVENING...FOLLOWED BY A SMALL CHANCE OF RAIN CLOSER TO DAYBREAK
AHEAD OF A WEAK LOW/MID LEVEL TROUGH AXIS EMBEDDED IN A MEAN
SOUTHWEST FLOW ALOFT.
FROM FRIDAY THROUGH SATURDAY NIGHT...A TRAIN OF SMALL AND
TRANSIENT SHORTWAVE IMPULSES WILL WORK THROUGH THE WFO PAH
FORECAST AREA. THE VARIABILITY IS GOING TO MAKE IT DIFFICULT TO GO
MUCH BEYOND CHANCE CATEGORY THROUGH FRIDAY NIGHT. THE INFLUENCE
WILL INITIALLY BE DIURNAL...BUT WEAK FORCING WILL DOMINATE
SATURDAY AND SATURDAY NIGHT IN THE WARM CONVEYOR BELT.
HOWEVER...THE POP SIGNAL GETS MORE PERSISTENT SATURDAY AND
SATURDAY NIGHT OVER EXTREME SOUTHERN ILLINOIS...MOST OF WEST
KENTUCKY AND SOUTHEAST MISSOURI...AS THE MEAN ISENTROPIC LIFT
ZONE REMAINS FOCUSED ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST.
CHANNELED VORTICITY ORIENTED PARALLEL TO THE UPPER FLOW WILL
MAINTAIN INTERMITTENT RAIN ACTIVITY THROUGH THE PERIOD.
LEANED CLOSER TOWARD THE HIGHER RESOLUTION NAM-WRF DETERMINISTIC
AND ENSEMBLE GUIDANCE...INCLUDING THE HRRR IN THE 06-18 HOUR TIME
FRAME...WITH MORE EMPHASIS TOWARD THE ECMWF AND CANADIAN GUIDANCE
TOWARD SATURDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 254 PM CDT THU MAY 14 2015
00Z OPS MODELS AND EC/GFS ENSEMBLE MEAN SOLUTIONS REMAINED IN GOOD
AGREEMENT WITH THE OVERALL UPPER AIR PATTERN. AT THE BEGINNING OF
THE PERIOD...A MID LEVEL TROF WILL EJECT NEGATIVE TILT FROM THE
PLAINS INTO THE UPPER MIDWEST SUNDAY. FRONT STILL OFF TO OUR WEST
BUT WITH MOISTURE AND INSTABILITY PRESENT IN AN UNSETTLED SW FLOW
ALOFT...CONTINUED WITH HIGH CHANCE POPS FOR CONVECTION. CONFIDENCE
REMAINS ABOVE AVERAGE.
FRONT WILL SETTLE SOUTH INTO THE AREA LATE SUNDAY NIGHT INTO MONDAY.
LIKELY POPS SUNDAY NIGHT AND ESPECIALLY ACROSS THE SE 2/3 OF THE
CWFA PER THE LATEST OUTPUT. WILL LINGER POPS MONDAY AS THE FRONT
WILL CONTINUE TO PROGRESS SOUTHEAST ACROSS THE AREA. DIMINISHING
POPS MONDAY EVENING...AND IT SHOULD BE DRY AFTER MIDNIGHT MONDAY
NIGHT.
HIGH PRESSURE SHOULD RESULT IN DRY WEATHER TUESDAY THROUGH TUESDAY
NIGHT. THE OVERALL MID LEVEL FLOW PATTERN FLATTENS OUT ACROSS THE
MID CONUS WITH A TROF OFF THE PACIFIC COAST AND OVER SE CANADA. THE
GFS/ECMWF SOLUTIONS OF THE PAST DAY OR SO SUGGEST MODEST MID LEVEL
SUPPORT AND MOISTURE MAY RESULT IN A FEW SHOWERS WEDNESDAY. THURSDAY
IS MORE UNCLEAR. THE MODELS SHOW DECREASING MOISTURE WITH HIGH
PRESSURE TRYING ONCE AGAIN TO BUILD SOUTHEAST. SO NO POPS FOR NOW
THURSDAY.
THE NEW ECMWF GUIDANCE TRENDED A BIT COOLER FOR MONDAY THROUGH
WEDNESDAY. OTHERWISE A CONSENSUS OF THE GFS/GFS ENSEMBLE MOS AND
PREVIOUS ECMWF NUMBERS WERE STEADY. WILL CONTINUE TO MONITOR THIS
TREND. FOR NOW...JUST SLIGHT ADJUSTMENTS TO OUR EXISTING NUMBERS AND
THE OVERALL MOS CONSENSUS FROM THE PAST 48 HOURS.
&&
.AVIATION...
ISSUED AT 1157 PM CDT THU MAY 14 2015
LOTS OF CLEAR SKY WILL GIVE WAY TO INCREASING HIGH CLOUDS BY
MORNING. SOUTHERLY WINDS WILL BE AROUND 5 KNOTS. SCATTERED DIURNAL
CUMULUS CLOUDS WILL FORM FRIDAY MORNING. THE ATMOSPHERE WILL BECOME
QUITE UNSTABLE BY AFTERNOON...LEADING TO BROKEN CUMULUS CLOUDS AND
SOME THUNDERSTORMS. THE GENERAL TREND SHOULD BE FOR STORMS TO
DEVELOP FROM SOUTHWEST TO NORTHEAST...REACHING KEVV/KOWB LATER IN
THE AFTERNOON. THERE IS ENOUGH OF A PROBABILITY OF STORMS TO
INTRODUCE THE MENTION OF VCTS AT ALL TAF SITES IN THE AFTERNOON.
PRECIP SHOULD DIMINISH IN THE EVENING...BUT WITH PLENTY OF MID LEVEL
CLOUDS REMAINING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...CN
AVIATION...MY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CDT FRI MAY 15 2015
TODAY AND TONIGHT... A WEAK COLD FRONT HAS DROPPED SOUTH TO JUST
NORTH OF INTERSTATE 80 PER SFC OBS AND RTMA ANALYSIS. EAST WINDS ARE
UNDERWAY IN THE PLATTE VALLEY. STRATUS NORTH OF THE FRONT ACROSS NRN
NEB COULD SPREAD SOUTH TO NEAR THEDFORD AND PERHAPS AS FAR SOUTH AS
BROKEN BOW BY MORNING. THE THUNDERSTORMS UNDERWAY ACROSS SWRN NEB
THIS MORNING SHOULD MOVE UP AND OVER THE FRONT PRODUCING RAIN COOLED
AIR WHICH WOULD KEEP THE FRONT IN OR NEAR THE PLATTE VALLEY UNTIL
AFTERNOON. THIS AFTERNOON...FRONT COULD BEGIN TO MOVE NORTH SLOWLY.
THE MODEL CONSENSUS SHOWS THE FRONT LIFTING RAPIDLY NORTH TONIGHT.
THE BEST GUESS ON THE SEVERE WEATHER IS A BIT OPTIMISTIC. STRONG
WINDS ALOFT...40 TO 50 KT AT 500 MB AND 60 KT AT 300 MB SHOULD MOVE
INTO SWRN NEB AROUND 18Z AND FIRE CONVECTION ON A WARM FRONT DRAPED
ACROSS THE SRN SANDHILLS BY 21Z...PERHAPS ALIGNED E-SE TOWARD
LEXINGTON. THE RAP SHOWS LARGE SCALE LIFT AT THE SAME TIME EMANATING
FROM A LONG WAVE TROF OVER THE SWRN U.S.
TORNADO PARAMETERS LOOK REASONABLY GOOD WITH NICELY CURVED
HODOGRAPHS NEAR THE FRONT FOR SEVERAL HOURS DURING THE AFTN. THIS
PRODUCES 0-3KM HELICITY OVER 400 M2/S2 AND WHEN COMBINED WITH THE
INSTABILITY THE ENERGY HELICITY INDEX IS OVER 4 ALONG THE FRONT.
THUS A TORNADO OR TWO COULD FORM. WINDS ALOFT ARE A BIT LINEAR AND
CONRAD CONTINUES TO SUGGEST SPLITTING DOMINANT RIGHT MOVING
SUPERCELLS.
NOTE THE RAP...THE FAVORED MODEL...MOVES THE FRONT VERY LITTLE TODAY
WHICH COULD ALLOW FOR SEVERE STORMS TO RIDE UP AND OVER THE FRONT
AND BECOME MORE OF A HAIL THREAT.
SPC SUGGESTED STORM ACTIVITY WOULD WEAKEN THIS EVENING AND IT IS
POSSIBLE THE LARGE SCALE LIFT AND UPPER LEVEL SUPPORT COULD DO THE
SAME CARRYING THE BULK OF THE STORM ACTION INTO NRN NEB BY 00Z AS
SUGGESTED BY THE MODEL CONSENSUS.
THE FORECAST USES A BLEND OF THE RAP...NAM...GEMREG...ARW AND NMM.
THE OTHER MODELS WERE TOO COARSE RESOLUTION TO CAPTURE THE SPIRIT OF
THE EVENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CDT FRI MAY 15 2015
DETERMINISTIC MODELS AND ENSEMBLE MEANS CONTINUE TO ADVERTISE A
PERSISTENT UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT
WEEK. BLOCKY SETUP ALONG THE WEST COAST INTO THE CENTRAL ROCKIES
WITH A HIGH AMPLITUDE RIDGE OVER WESTERN CANADA OVER THE TOP OF A
BROAD TROUGH EXTENDING SOUTHWARD TOWARD THE BAJA OF CALIFORNIA.
RIDGE TO THE EAST WILL BEGIN TO FLATTEN INTO EARLY NEXT WEEK AS A
LOW BUILDS INTO SOUTHEAST CANADA. THE MEAN UPPER LEVEL FLOW OVER THE
CENTRAL PLAINS REMAINS OUT OF THE SOUTHWEST THROUGH THE LONG RANGE
PERIOD AND IN THE CROSSHAIRS OF SEVERAL SHORTWAVE PERTURBATIONS
ASSOCIATED WITH THE WESTERN CONUS TROUGH.
ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE AGAIN ON SATURDAY AS
STRONG PV MAX AND UPPER LEVEL JET STREAK EJECT NORTHEAST OUT OF THE
FOUR CORNERS REGION. LEE SIDE LOW AND ASSOCIATED PACIFIC FRONT MAKE
LITTLE EASTWARD PROGRESSION TOWARD THE EASTERN NEBRASKA PANHANDLE BY
THE BEGINNING OF THE PERIOD. SCATTERED ELEVATED STORMS LEFTOVER FROM
FRIDAY NIGHT SHOULD BE PUSHING NORTH AND EAST OF THE CWA DURING THE
MORNING HOURS...AIDED BY A VEERING LLJ. CONVECTIVE INITIATION IS
LIKELY ONCE AGAIN BY MID AFTERNOON IN AN INCREASINGLY UNSTABLE WARM
SECTOR EAST OF THE PACIFIC FRONT. MODELS ARE STRUGGLING WITH THEIR
HANDLING OF WARM SECTOR RECOVERY...AND ANY CLOUD COVER WILL HAVE A
SIGNIFICANT IMPACT ON THE DEGREE OF DESTABILIZATION. HOWEVER SEVERE
STORMS WILL STILL BE POSSIBLE GIVEN THE STRONG FORCING FOR ASCENT
AND FAVORABLE DEEP LAYER SHEAR. WIND PROFILES CONTINUE TO LOOK
FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...FAVORING
UPSCALE GROWTH AS THE THUNDERSTORM ACTIVITY EVOLVES THROUGH THE
AFTERNOON AND EVENING. LARGE HAIL...DAMAGING WINDS WILL BE THE
PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL ALSO NEED TO BE CLOSELY
WATCHED AS SOME AREAS MAY EXPERIENCE SEVERAL ROUNDS/TRAINING
THUNDERSTORMS.
SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY ACROSS THE NORTHERN
TIER OF THE CWA. LOW LEVEL MOISTURE WRAPS AROUND THE BACKSIDE OF THE
SFC LOW NOW OVER THE DAKOTAS AND BACK INTO NEBRASKA...UNDERNEATH
ANOMALOUSLY COLD AIR ALOFT ASSOCIATED WITH THE PASSING OF THE
UPPER LEVEL LOW. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS
EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS.
THE MIDDLE OF THE WEEK LOOKS COOL AND WET AS ANOTHER UPPER LEVEL
SHORTWAVE TROUGH PIVOTS NORTHEAST THROUGH THE EASTERN ROCKIES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM CDT THU MAY 14 2015
MAIN FCST CHALLENGE IS TIMING OF TSRA FOR THE KLBF TAF AND
SOUTHERN PORTION OF THE AREA...AND POTENTIAL FOR STRATUS AND BR
FOR THE KVTN TAF SITE OVERNIGHT. FIRST FOR TSRA...ISOLD TSRA HAS
DEVELOPED IN EXTREME SW NEB BUT BELIEVE MORE DEVELOPMENT WILL BE
COMING AS LLJ DEVELOPS IN WRN KS INTO SW NEB TWD MIDNIGHT.
ISENTROIC LIFT IN CONCERT WITH INCREASING ELEVATED INSTABILITY AS
A RESULT OF THE LLJ WILL RESULT IN SCT TSRA DEVELOPMENT AND HAVE
INCLUDED IN KLBF TAF AFTER 06Z. THESE SHOULD MOVE NWD THROUGH THE
NIGHT THOUGH COVERAGE IS A BIT IN QUESTION AS LATEST FEW HRRR RUNS
HAVE SHOWN LIMITED COVERAGE IN SWRN NEB TONIGHT.
NEXT WILL BE POTENTIAL FOR BR/STRATUS OVERNIGHT FURTHER N. STRATUS
CURRENTLY JUST NORTH OF THE NEB/SD BORDER DOES HAVE SWD MOVEMENT
THOUGH ERRODING ON THE WEST SIDE AS INCREASING WRLY MID LEVEL FLOW
CONTINUES. HOWEVER...BELIEVE AFTER SUNSET SHOULD SEE MORE SWD
PROGRESSION AS RAP/NAM SUGGEST AND WOULD BE EXPECTED NORTH OF
DEVELOPING WARM FRONT. HAVE INCLUDED BR IN THE KVTN TAF OVERNIGHT
THOUGH DID NOT TAKE VSBY TO IFR OR BELOW YET. GFS-LAMP ALSO
SUGGEST S THIS SCENARIO...AND THIS IS A BIT OF A CHANGE SINCE THE
LAST TAF FOR KVTN.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
432 AM EDT FRI MAY 15 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL KEEP THE PIEDMONT MOSTLY DRY
INTO THE WEEKEND...BUT INCREASING MOISTURE ON THE WESTERN EDGE OF
THE SURFACE HIGH WILL BRING PRECIPITATION CHANCES OVER THE
MOUNTAINS. A COLD FRONT WILL PUSH THROUGH THE REGION EARLY NEXT WEEK
ALLOWING BETTER PRECIPITATION CHANCES FOR THE ENTIRE REGION MONDAY
AND TUESDAY. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN
BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EDT...WATER VAPOR IMAGERY SHOWS A SHORTWAVE CROSSING
THE BASE OF THE SOUTHERN APPALACHIANS EARLY THIS MORNING. THIS
FEATURE IS COMBINING WITH SOUTHERLY UPSLOPE FLOW TO PRODUCE ISOLATED
SHOWERS OVER THE WESTERN HALF OF THE FORECAST AREA THIS
MORNING...AND SPOTTY LIGHT SHOWERS WILL LIKELY MOVE EAST INTO THE
PIEDMONT UNDER THE PASSING WAVE THROUGH DAYBREAK. THE SHORTWAVE WILL
MOVE EAST OF THE AREA BY LATE MORNING...WITH MOST AFTN AND EVENING
ISOLD TO SCATTERED SHOWERS AND TSTMS AFFECTING MAINLY THE MTNS IN
WEAK UPSLOPE AND LOW LEVEL CONVERGENCE ACROSS THE HIGHER TERRAIN.
CLOUDINESS WILL KEEP INSTABILITY CONTAINED TODAY AND ALSO PUT A
DAMPER ON MAX TEMPS IN SPITE OF THE WARMING THICKNESSES. A SHIELD OF
MID AND HIGH CLOUDS IS ALREADY IN PLACE ACROSS THE REGION. SCT TO
BKN LOWER LEVEL STRATOCUMULUS IS FILLING IN IN THE MOIST SOUTHERLY
FLOW AROUND THE COASTAL HIGH PRESSURE CENTER...AND ANY DEGREE OF
HEATING WILL ALLOW CLOUDS TO FILL BACK IN THROUGH THE DAY. MAXES
WILL BE MAINLY IN THE 70S...EXCEPT FOR SOME 60S ALONG THE HIGHER
TERRAIN THIS AFTN...AND AROUND 80 IN THE LOWER PIEDMONT.
A 500 MB RIDGE WILL BUILD OVER THE REGION THE REST OF THIS AFTERNOON
THROUGH TONIGHT. S TO SW UPSLOPE FLOW WILL CONTINUE IN THE SW MTNS
INTO THE OVERNIGHT HOURS...WITH THE BEST CHANCE OF LINGERING ISOLD
NOCTURNAL SHOWERS IN THIS AREA. WILL LEAN TOWARD THE WARMER BIAS
CORRECTED MIN TEMPS FOR TONIGHT GIVEN THE CONTINUED CLOUDS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 AM FRI...UPPER RIDGE AMPLIFIES OVER THE SOUTHEAST OVER THE
WEEKEND. ANY SIGNIFICANT FEATURES REMAIN TO OUR NORTH AND WEST. SSW
TO SW FLOW CONTINUES IN THE LOW LEVELS WHICH WILL PROVIDE PLENTIFUL
MOISTURE AND HELP INITIATE CONVECTION OVER THE HIGHER TERRAIN VIA
UPSLOPING. THROUGH SUNDAY THE BERMUDA HIGH REMAINS DOMINANT...AND
LAPSE RATES ARE TOO POOR OVER THE PIEDMONT TO EXPECT CONVECTION
THERE. ON SUNDAY A DEEP LOW WILL MOVE EWD OUT OF THE DAKOTAS ON AN
EVENTUAL TRACK ACRS THE NRN GREAT LAKES. AS GRADIENT TIGHTENS ON THE
UPSTREAM SIDE OF THE EAST COAST RIDGE...LOW LEVEL FLOW VEERS SUN
NIGHT TO MORE WESTERLY. COVERAGE WILL WANE SUNDAY NIGHT BUT ISOLATED
ACTIVITY MAY CONTINUE NEAR THE TENN BORDER INTO MON MRNG. TEMPS WILL
BE A CATEGORY OR SO ABOVE NORMAL DURING THE PERIOD.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 200 AM FRI...POPS PEAK MONDAY AS PREFRONTAL CONVERGENCE AND
MOISTURE COINCIDE WITH DIURNAL INSTABILITY...REMAINING ELEVATED UNTIL
COLD FRONT PASSES EARLY TUE. MONDAY IS ALSO EXPECTED TO BE THE
WARMEST DAY OF THE WEEK AS THICKNESSES PEAK. MAX TEMPS WILL BE 7-10
DEGREES ABOVE NORMAL. DRY CONTINENTAL HIGH PRESSURE RETURNS IN ITS
WAKE LASTING THRU WED...THOUGH TEMPS REMAIN ABOVE NORMAL. WHILE THE
15/00Z GFS AND 14/12Z EC BEAR LITTLE DIFFERENCE PRIOR TO THIS
TIME...BY WED NIGHT THEY HAVE DIVERGED IN THEIR DEPICTION OF THE
UPPER PATTERN OVER THE WEST COAST. THIS LEADS TO SOME SUBTLE
DIFFERENCES OVER OUR AREA FOR THE LATE WEEK. WHILE THE UPPER FLOW IS
OF LOW AMPLITUDE ON BOTH...THE EC IS SLIGHTLY CYCLONIC OVER THE AREA
WHILE THE GFS IS ZONAL. A WEAK BAROCLINIC ZONE APPEARS LIKELY TO BE
IN PLAY ACROSS THE UPPER SOUTH...WHICH WOULD HELP RE-ACTIVATE MAINLY
DIURNAL CONVECTION OVER PARTS OF THE AREA. TEMPS WILL TREND DOWNWARD
SLIGHTLY LATER IN THE WEEK...THOUGH WITH MAXES REMAINING ABOVE NORMAL
AND WITH RESTRICTED DIURNAL RANGES DUE TO CLOUD COVER.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
AT KCLT...MVFR STRATUS HAS SET UP QUICKLY THIS MORNING ON THE
STRENGTH OF LIGHT BUT MOIST SOUTHERLY FLOW JUST OFF THE SURFACE. THE
CONSENSUS OF MODEL PROFILES AND MOS GUIDANCE REMAINS THAT A FAIRLY
PROLONGED PERIOD OF MVFR IS IN STORE THROUGH THE LATE MORNING
HOURS...POSSIBLY LINGERING INTO EARLY AFTERNOON. THE MET GUIDANCE
AND RAP PROFILES ALSO HINT THAT PERIODS OF DAYBREAK IFR WILL BE
POSSIBLE...BUT THIS HAS YET TO OCCUR AT ANY OF THE NEARBY OBSERVING
LOCATIONS...SO WILL KEEP THE FORECAST NO WORSE THAN MVFR FOR NOW.
CIGS WILL SLOWLY RISE BACK TO VFR THIS AFTN AND SCATTER TOWARD
EVENING. EXPECT SE TO S FLOW THROUGH THE PERIOD AT SPEEDS LESS THAN
10 KT.
ELSEWHERE...VFR STRATUS/STRATOCUMULUS CIGS CONTINUE TO DEVELOP AND
LOWER THIS MORNING UNDER MOIST SRLY FLOW. THERE IS SOME POTENTIAL
FOR IFR CIGS AROUND DAYBREAK THROUGHOUT...BUT CHANCES APPEAR BEST IN
MODEL SOUNDINGS OVER KAVL...SO WILL FEATURE TEMPO IFR THERE. THE
CLOUDS SHOULD LARGELY PRECLUDE ANY SIGNIFICANT MORNING FOG ISSUES.
EXPECT CIGS TO SLOWLY RISE THROUGH MVFR THROUGH LATE MORNING...WITH
VFR CIGS LIKELY THIS AFTN...SCATTERING THIS EVENING. EXPECT SOME
DEGREE OF SOUTHERLY FLOW THROUGH THE PERIOD...WITH SPEEDS LESS THAN
10 KT.
OUTLOOK...MOISTURE WILL GRADUALLY INCREASE THROUGH THE
WEEKEND...WITH DIURNAL CONVECTIVE CHANCES INCREASING AS
WELL...ESPECIALLY OVER THE MTNS. THE POTENTIAL FOR EARLY MORNING
STRATUS AND FOG WILL ALSO INCREASE OVER THE WEEKEND INTO EARLY NEXT
WEEK.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-06Z
KCLT HIGH 95% HIGH 84% HIGH 100% HIGH 100%
KGSP HIGH 90% HIGH 82% HIGH 100% HIGH 100%
KAVL HIGH 93% HIGH 93% HIGH 100% HIGH 100%
KHKY HIGH 93% HIGH 90% HIGH 100% HIGH 100%
KGMU HIGH 87% HIGH 89% HIGH 100% HIGH 100%
KAND HIGH 90% HIGH 90% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
425 AM CDT FRI MAY 15 2015
.DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
&&
.AVIATION...
06Z TAF CYCLE
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE PERIOD. A WARM
FRONT WILL MOVE NORTHEAST ACROSS SITES ON FRIDAY WITH VCTS
OCCURING AT ALL SITES MAINLY AFTER 15/15-16Z. CHANCES FOR
VCSH/VCTS ARE EXPECTED TO PERSIST THROUGH THE END OF THE PERIOD. LIGHT
WINDS WILL INCREASE TO SOUTH WINDS BETWEEN 6-10 KTS ON FRIDAY AND
BECOME LIGHT TOWARDS 16/00Z.
04
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1206 AM CDT FRI MAY 15 2015
.UPDATE...
A LOOSELY ORGANIZED CLUSTER OF T-STORMS CONTINUES TO MOVE SLOWLY
THROUGH THE ROLLING PLAINS AND FAR SE TX PANHANDLE. SEVERE
WEATHER IS NOT EXPECTED OVERNIGHT...BUT HEAVY RAINFALL MAY CAUSE
SOME LOCALIZED FLOODING.
&&
.AVIATION...
TSRA WILL CONTINUE IN THE VICINITY OF KCDS THROUGH 07 UTC OR SO.
OTHERWISE...PATCHY STRATUS MAY BRING SOME LOW CEILINGS AT KPVW
AND KLBB THROUGH ABOUT SUNRISE BUT CONFIDENCE IN THIS IS LOW.
SURFACE WINDS WILL RETURN TO THE S-SW AND BECOME BREEZY DURING THE
DAY FRIDAY. SCATTERED TSRA WILL DEVELOP LATE IN THE DAY WITH A
GOOD CHANCE TO IMPACT SOME OR ALL OF THE TERMINALS FRIDAY
EVENING.
&&
.PREV DISCUSSION... /ISSUED 657 PM CDT THU MAY 14 2015/
UPDATE...
THE SEVERE THUNDERSTORM WATCH HAS BEEN EXPANDED TO COVER THE
ENTIRE FORECAST AREA THROUGH 11 PM. THE LATEST HRRR GRADUALLY
MORPHS THE CLUSTER OF TSTMS ACROSS THE WRN SPLNS INTO A SQUALL
LINE WHICH THEN MOVES EAST TONIGHT. WE HAVE ALSO INCREASE THE POPS
FOR MOST AREAS.
AVIATION...
-TSRA IS EXPECTED AT KLBB AND PVW THIS EVENING...THEN SEVERAL
HOURS LATER AT KCDS. SOME SEVERE WIND WINDS AND LARGE HAIL ARE
POSSIBLE. VFR CONDITIONS WILL RETURN LATE TONIGHT...ALTHOUGH
THERE IS A LOW POTENTIAL FOR LOW CEILINGS...ESPECIALLY AT KCDS. SW
BREEZES WILL INCREASE FRIDAY MORNING.
PREV DISCUSSION... /ISSUED 214 PM CDT THU MAY 14 2015/
SHORT TERM...
FORECAST THINKING CONTINUES ON TRACK WITH THAT PROVIDED IN THE NOON
UPDATE. CAPE VALUES HAVE INCREASED A FAIR BIT IN THE LATEST
MESOANALYSES PEAKING AT VALUES IN EXCESS OF 3KJ/KG PARTICULARLY
ACROSS OUR SOUTHERN COUNTIES. BULK SHEAR CONTINUES TO BE RUNNING
AROUND 35 KTS THOUGH ONE OF THE MORE REMARKABLE FIELDS IN THIS
MORNING/S RUNS IS THE HELICITY...MOST NOTABLE THE 0-1KM FIELDS WHICH
RAMP UP RAPIDLY THIS EVENING. THE ONE NEGATIVE...AND HISTORICALLY
THIS CAN BE A DEAL-BREAKER...IS THE PRESENCE OF A PERSISTENT CIRRUS
SHIELD. AS SUCH THE SEVERE THREAT IS CONDITIONAL ON INITIATION OF
DEEP CONVECTION. HOWEVER...IF THINGS DO BECOME ESTABLISHED...ALL
FORMS OF CONVECTIVE SEVERE WILL BE LIKELY. DATA SUGGESTS THAT THE
WINDS WILL RAPIDLY BACK AROUND 00Z WITH ATTENDANT LOW LEVEL MOISTURE
SURGE AND ENHANCE THE TORNADO THREAT. ASSUMING DEEP CONVECTION
OCCURS...WOULD LOOK FOR INITIAL ACTIVITY TO BE SOMEWHAT DISCRETE AND
EVOLVE TOWARD SOME SORT OF QLCS LATER THIS EVENING. AFTER THE
ACTIVITY WANES THIS EVENING...COULD SEE A BIT OF FOG TOWARD
MORNING ESPECIALLY ACROSS THE ROLLING PLAINS. WITH THAT OUT OF THE
WAY...WE SHOULD GET A RESPITE IN CONVECTION UNTIL LATE FRIDAY
AFTERNOON OR EVENING WITH ANOTHER SYSTEM MOVING ACROSS AS
DISCUSSED IN THE LONG TERM.
LONG TERM...
MODELS ARE CHANGING COURSE A LITTLE BIT WITH REGARDS TO FRIDAY
CONVECTION. THE UPPER LEVEL JET STREAK WILL COME OUT OF THE
SOUTHWESTERN US FARTHER SOUTH CLOSER TO WEST TEXAS. THIS WILL
LEAVE THE REGION IN DIVERGENCE FLOW ALOFT. OVERNIGHT CONVECTION
LOOKS MORE LIKELY FROM FRIDAY NIGHT THROUGH MUCH OF SATURDAY
MORNING. A PACIFIC COLD FRONT WILL EVENTUALLY OVERTAKE A
RETREATING DRYLINE FRIDAY NIGHT DEVELOPING CONVECTION INITIALLY IN
EASTERN NEW MEXICO. A LOW LEVEL JET RAMPING UP WILL SUSTAIN
CONVECTION IN MORE OR LESS OF A LINEAR FORM. THIS WILL BE COUPLED
WITH STRONG HEIGHT FALLS OVERNIGHT. STEEPER LAPSE RATES ENTERING
THE REGION BECAUSE OF COOLING ALOFT WILL ALLOW THE POSSIBILITY OF
SEVERE STORMS. THE PACIFIC COLD FRONT WILL THEN STALL OUT OVER THE
ROLLING PLAINS WITH STRONGER LOW LEVEL CONVERGENCE ON SATURDAY
AFTERNOON. THE UPPER LEVEL JET POSITION WILL FAVOR THE CENTRAL
PLAINS RATHER THAN THE SOUTHERN HIGH PLAINS. ALTHOUGH THE SURFACE
CONVERGENCE WILL FAVOR SOME INITIATION SATURDAY AFTERNOON OR
EVENING OVER THE ROLLING PLAINS.
SUNDAY WILL SEE A BREAK FROM THE CONVECTION CHANCES AS THE
LONGWAVE TROUGH EJECTS OUT INTO THE PLAINS AND MIDWEST. A CANADIAN
COLD FRONT ON MONDAY WILL ALLOW LOW LEVEL MOISTURE TO BE DRAWN
BACK INTO THE REGION. OUR UNSETTLED WEATHER PATTERN WILL CONTINUE
NEXT WEEK WITH WESTERN CONUS TROUGHING RAPIDLY DEVELOPING AGAIN
NEXT WEEK. AT THE MOMENT...MONDAY-TUESDAY IS THE AGREED UPON
TIME FRAME FOR BEST CONVECTION IN BOTH THE GFS AND ECMWF.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 55 77 53 74 / 10 10 50 0
TULIA 58 79 58 77 / 30 10 60 10
PLAINVIEW 59 79 59 77 / 30 10 60 10
LEVELLAND 59 80 59 78 / 10 10 60 0
LUBBOCK 60 81 61 80 / 30 10 60 10
DENVER CITY 59 81 58 78 / 10 10 60 0
BROWNFIELD 61 82 60 80 / 10 10 60 10
CHILDRESS 64 83 64 83 / 70 10 60 50
SPUR 63 82 63 83 / 70 10 60 20
ASPERMONT 66 83 66 85 / 70 20 60 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1142 PM CDT THU MAY 14 2015
.DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
MAINLY VFR CONDITIONS WILL BECOME MVFR AT MOST SITES BY 09Z. IF
THE LATEST HRRR IS CORRECT...SHOWER AND THUNDERSTORMS MAY BEGIN
AFFECTING KCLL BEFORE 12Z. HOWEVER...FELT THAT A CONSENSUS OF THE
OTHER MODELS IS A BETTER SOLUTION. FOR MOST SITES EXPECT SHOWERS
AFTER 15Z AND THUNDERSTORMS AFTER 18Z. STREAMER SHOWERS ARE
POSSIBLE AT THE COAST BY 10Z.
40
&&
.PREV DISCUSSION... /ISSUED 900 PM CDT THU MAY 14 2015/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
00Z SOUNDINGS SHOW PW VALUES NEAR 1.50 INCHES WITH SOME SLIGHTLY
DRIER AIR IN THE 850-700 LAYER. SFC ANALYSIS SHOWS TWO WEAK
OUTFLOW BOUNDARIES...ONE JUST SOUTH OF LUFKIN AND ANOTHER BETWEEN
HONDO AND COTULLA. NEITHER FEATURE LOOK TO BE MUCH OF A FACTOR
FOR WX OVER SE TX. BEST 850 MB MSTR IS OVER N TX/S OK BUT
DISCERNIBLE TROUGHS WERE NOTED OVER THE STATE. 700 MB MSTR WAS
LOCATED OVER W LA WITH SUBTLE WARMING AT THE 700 MB LEVEL. 300 MB
ANALYSIS SHOWS UPPER LEVEL WINDS REMAIN DIVERGENT OVER THE
EASTERN 2/3RDS OF THE STATE AND THIS IS NOT EXPECTED TO CHANGE
OVER THE NEXT 24 HOURS.
SHRA/TSRA ACTIVITY HAS WANED WITH THE LOSS OF HEATING BUT STILL
WATCHING AN AREA OF CONVECTION OVER SOUTH TEXAS MOVING TOWARD
JACKSON COUNTY. FEEL THIS ACTIVITY WILL WEAKEN AS IT MOVES EAST
AND PROBABLY DISSIPATE. SHORT TERM MODELS SHOW SOME STREAMER
SHRA DEVELOPING AFTER 06Z SO WILL LEAVE 20 POPS FOR TONIGHT.
SHORT TERM GUIDANCE IS BULLISH WITH RAIN CHANCES ON FRIDAY. THE
RAP/GFS/NAM ALL SHOW A STRONG VORT LOBE MOVING INTO THE AREA IN
THE EARLY AFTN. UPPER LEVEL WINDS REMAIN DIVERGENT WITH A SPEED
MAX APPROACHING IN THE AFTN. FCST SOUNDINGS SHOW PW VALUES PEAKING
BETWEEN 1.7-1.9 INCHES BY 21Z AND CONVECTIVE TEMPS BETWEEN 80 AND
83 DEGREES. THE ECMWF AND CANADIAN ARE CONSIDERABLY DRIER WITH
LITTLE TO NO RAIN FOR THE AREA. WILL AWAIT THE 00Z MODELS BEFORE
POSSIBLY RAISING POPS FOR FRIDAY.
LASTLY...SOME HEFTY RAINFALL TOTALS YET AGAIN TODAY WITH KUTS
TOPPING THE CHARTS WITH 1.94 INCHES. SEE THE CLIMATE SECTION BELOW
FOR OTHER CLIMATE INFORMATION. SOME 3-4 INCHES TOTALS IN HOUSTON
COUNTY...AND 2-3 INCH TOTALS IN PARTS OF WALKER...MONTGOMERY AND
AUSTIN COUNTIES. 43
CLIMATE...
AS MENTIONED ABOVE HUNTSVILLE (KUTS) RECEIVED 1.94 INCHES OF RAIN
TODAY. THIS BRINGS THE MONTHLY TOTAL TO 7.53 INCHES. THE MAY
MONTHLY AVERAGE IS 4.94 INCHES. OVER THE LAST 30 DAYS (APR 15
THROUGH MAY 15)...HUNTSVILLE HAS RECEIVED 13.94 INCHES OF RAIN.
SUGAR LAND (KSGR) RECEIVED 1.24 INCHES OF RAIN TODAY WITH A
MONTHLY TOTAL OF 5.11 INCHES AND A 30 DAY TOTAL OF 12.83 INCHES.
HOUSTON HOBBY ONLY RECEIVED A TRACE OF RAIN TODAY BUT HAS A 30 DAY
TOTAL OF 11.37 INCHES. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 71 83 71 86 72 / 20 40 20 30 30
HOUSTON (IAH) 72 84 72 86 74 / 20 40 20 30 20
GALVESTON (GLS) 76 80 76 82 76 / 20 40 20 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
405 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER. AT
THE SURFACE...SOUTHEAST WINDS MAY INCREASE ENOUGH FOR A LAYER OF
STRATOCUMULUS TO DEVELOP ALONG THE SOUTHERN APPALACHIANS.
MODERATE CONFIDENCE THERE WILL BE A SCATTERED TO BROKEN LAYER OF
CLOUDS WITH CEILINGS OF 3-5KFT. LOWER CONFIDENCE THAT THESE LOWER
CLOUDS WILL DEVELOP OVER KBCB/KDAN/KROA/KBLF.
MODELS HAVE BEEN CONSISTENT IN FORECAST OF LIGHT PRECIPITATION
JUST WEST OF THE MOUNTAINS. PROBABILITY STILL ENOUGH TO INCLUDE
SHOWERS IN THE VICINITY OF KLWB AND KBLF THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI MAY 15 2015
BIGGEST CHANGE TO THIS PERIOD WILL BE TO REMOVE THE SEVERE STORM
POTENTIAL OVERNIGHT CURRENTLY IN THE SERVICE SUITE.
SATELLITE AND SURFACE OBSERVATIONS SHOWING A VERY WEAK PRESSURE
GRADIENT AND LOW CLOUD AND FOG FAIRLY WIDESPREAD ACROSS THE
REGION IN THE WAKE OF THE RAIN. STILL SOME DRIZZLE BEING REPORTED
IN WI IN WHAT THE RAP SOUNDINGS INDICATE AS A 2KM DEEP MOIST
LAYER. SPORADIC REPORTS OF NEAR ZERO VISIBILITY ARE OUT THERE AS
OF 08Z /MAINLY IOWA/...BUT WEB CAMERAS ACROSS THE AREA DONT REVEAL
WIDESPREAD REDUCTIONS TO VISIBILITY. OVERALL IDEA TODAY IS
SHORTWAVE RIDGING BUILDING IN AND DEEPER MIXING...BUT HAVE TAKEN A
PESSIMISTIC APPROACH WITH MORE SUN SEEN IN THE AFTERNOON. WILL
CONTINUE TO MONITOR FOR MORE WIDESPREAD FOG ISSUES AND FOR NOW
WILL HANDLE THIS WITH SPECIAL WX STATEMENTS.
PREVIOUS FORECAST AND CURRENT MESSAGING CONTAINS A SEVERE RISK
OVERNIGHT AS THE WARM FRONT...NOW LOCATED ROUGHLY ALONG
I-80...LIFTS INTO THE AREA. A SECONDARY MARITIME TROPICAL AIRMASS
RESIDES SOUTH OF I-70 WITH 65-70F DEWPOINTS...NOT TOO FAR AWAY.
THE 15.00Z NAM IS REALLY THE OUTLIER ON THE MUCAPE FORECAST INTO
THE AREA /THROUGH ITS ENTIRE FORECAST/ AND FEEL IT MUST BE REDUCED
ABOUT 30 PERCENT BASED ON SOUNDINGS AND LATEST MODEL CONSENSUS. AS
THE SPOKE OF ENERGY FROM THE SWRN U.S. LONG WAVE TROUGH ROTATES
NORTH //NOW IN NM/AZ//...HEIGHTS WILL FALL IN THE LOW-LEVELS AND
THE MOISTURE TRANSPORT WILL ENHANCE IN THE DAKOTAS/WRN MN...BUT
PRETTY FAR WEST. BY THE THE OVERNIGHT HOURS...AN AXIS OF MOISTURE
CONVERGENCE AND ABOUT 500 J/KG OF MUCAPE WILL RUN FROM KABR-KLSE.
BETTER CONVERGENCE ALONG THE WARM FRONT IN THE LOW LEVELS WILL BE
OCCURRING FURTHER WEST. HAVE KEPT 30S PERCENT CHANCES FOR THAT
PERIOD FOR THUNDERSTORMS...BUT THE WIND SHEAR IS VERY LOW AND THE
LESS AGGRESSIVE MODELS WITH MOISTURE /15.00Z GFS/ SUGGEST SOME
CAPPING OF 50-80J IS IN PLACE FOR 1-2KM PARCELS BEING LIFTED. SO
COVERAGE OF STORMS IS ALSO IN QUESTION. OVERALL...DIDNT SEE AN
ORGANIZED THREAT TO SPEAK OF FOR MESSAGING IN OUR SERVICE. WILL BE
PULLING THAT MENTION. SPC DAY 1 OUTLOOK WOULD AGREE WITH THIS
ASSESSMENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI MAY 15 2015
SATURDAY WILL SEE WARMER CONDITIONS AS THE WARM FRONT SHIFTS FURTHER
NORTH INTO THE NORTHERN FORECAST AREA AND NRN WI. DEWPOINTS AND
CAPE WILL BE ON THE INCREASE AND PROBABLY ABOUT 1000 J/KG OF
MLCAPE WILL BE PRESENT IN THE AFTERNOON. HOWEVER...FORCING IS
MINIMAL DURING PEAK HEATING WITH FAIRLY UNIFORM S-SE FLOW IN THE
FORECAST AREA IN THE WARM SECTOR. THE WILD CARD MAY BE ANY
CONVECTIVE VORTICITY THAT IS GENERATED IN THE SRLY FLOW. HAVE LEFT
SMALL RAIN CHANCES IN THE AFTERNOON. IT COULD BE A WARM DAY
SATURDAY AND BUMPED HIGHS A BIT WITH 19-21C SUGGESTED AT 925MB
FROM THE 15.00Z GUIDANCE /4-5C WARMER THAN FRIDAY/.
THE BIG STORY CONTINUES TO BE THE SUNDAY POTENTIAL FOR SEVERE
STORMS. POTENTIAL IS A GOOD WORD AS IT COULD BE A FAVORABLE DAY
FOR TORNADOES...BUT ALSO COULD RAIN THROUGH THE MORNING AND TURN
INTO NO STORY. THERE IS A BIG DIFFERENCE BETWEEN THE
DETERMINISTIC GUIDANCE WITH THE 15.00Z AND 14.18Z NAM RUNS SUGGESTING
A GOOD SETUP FOR SUPERCELL TORNADOES AND THE OVERALL SYNOPTICS AND
TIMING. HOWEVER...IT IS AN OUTLIER AS THE 15.00Z ECMWF/GFS AND
15.03Z/21Z SREFS ALL SUGGEST A DIFFERENT OUTCOME. THAT OUTCOME
WOULD INCLUDE STRONG MOISTURE TRANSPORT CONVERGENCE COMING INTO
THE AREA EARLY ON SUNDAY FROM THE WEST /SUNRISE/ AND SHIFTING EAST
ACROSS THE AREA. THERE WOULD PROBABLY BE ENOUGH INSTABILITY AND
INCREASING DEEPER STRONGER SHEAR FOR SOME MARGINALLY SEVERE
STORMS THEN. POSSIBLY A SMALL WINDOW IN WI FOR SEVERE STORMS TO
REDEVELOP LATER...BUT THIS SEEMS TO SHIFT NORTHEAST QUICKLY. THE
SLOWER 15.00Z AND 14.18Z NAM RUNS SUGGEST A SLOWER TIMING AND LESS
MORNING CONVECTION INTO WI...FAVORING A BETTER SUNDAY AFTERNOON
SEVERE STORM OUTBREAK.
IMPORTANTLY...SUNDAY HAS EXCELLENT DEEP SHEAR THROUGH 10KM...AND
TIMING AND INSTABILITY ARE THE MAIN PROBLEMS THAT NEED RESOLUTION. SPC
DAY 3 DISCUSSION MAINTAINS THE SLIGHT RISK OVER THE AREA...WHICH
SEEMS ON TRACK FOR THE DIFFERENCES THAT REMAIN ON SUNDAYS OUTCOME.
IT IS ONLY FRIDAY MORNING...AND THESE SWRN U.S. SYSTEMS ARE VERY
DEPENDENT ON THE ENERGY OVER THE PACIFIC BEING RESOLVED CORRECTLY
BY THE MODEL INITIALIZATION. THE NAM SKILL IN THE OUTER HOURS IS
NOT AS FAVORABLE AS WITHIN A DAY. WILL TRY TO STRESS THAT
DIFFERENCES EXIST ON HOW SUNDAY COULD PLAY OUT...BUT THAT A RISK
OF ORGANIZED SEVERE WEATHER EXISTS.
MONDAY THROUGH THURSDAY...AFTER THIS DEEPENING LOW AND SHOWER
CHANCES SHIFT EAST...THE WEEK SHOULD HAVE SLIGHTLY BELOW NORMAL
TEMPERATURES AND MAINLY DRY UNDER CONFLUENT NORTHWEST FLOW AND
CANADIAN SOURCED HIGH PRESSURE. COLDEST DAYS WILL BE ONDAY AND
TUESDAY...THEN SOME RISE EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1110 PM CDT THU MAY 14 2015
CIGS...
MVFR/IFR ARE EXPECTED INTO FRIDAY MORNING. BUFKIT SOUNDINGS
SUGGEST A DECREASE IN THE LOW SATURATION AS MIXING AND SINKING AIR
START TO ENTRAIN SOME DRIER AIR. PREVIOUSLY...IT APPEARED THERE
COULD BE A BREAK INTO SCT SKIES BY EARLY TO MID AFTERNOON - AFTER
18Z FRI. HOWEVER...LATEST RAP/NAM12 BUFKIT SOUNDINGS SUGGESTING THIS
COULD OCCUR A FEW HOURS EARLIER. WILL REFINE FORECAST A BIT TOWARD
THIS. ANOTHER ROUND OF MVFR CIGS LOOKS POSSIBLE AS A WARM FRONT
LIFTS NORTHWARD ACROSS THE REGION OVERNIGHT FRIDAY.
WX/VSBY...
AREA OF SHOWERS MAKING STEADY PROGRESS NORTHEAST LATE
THIS EVENING. THEY HAVE ALREADY CLEARED KRST AND WILL PUSH PAST KLSE
BEFORE 06Z. VSBY RESTRICTIONS SHOULD PERSIST INTO THE OVERNIGHT
HOURS FROM FOG DUE TO THE COMPLETED RAINFALL AND SATURATED AIRMASS.
NUMERICAL GUIDANCE BRINGS CONFIDENCE DOWN A BIT THOUGH...POINTING TO
MUCH QUICKER IMPROVEMENT - ESPECIALLY AT KLSE. WILL KEEP AT LEAST
MVFR VSBY UNTIL BOUNDARY SWINGS WINDS TO A WESTERLY DIRECTION.
WINDS...
UPPER LEVEL SHORTWAVE TROUGH LIFTS NORTHEAST ACROSS THE
REGION TONIGHT...TAKING A SFC FRONT WITH IT. WINDS SHOULD SWITCH
FROM SOUTHEAST TO WESTERLY OVERNIGHT/EARLY FRI MORNING. LIKELY
BECOMES A BIT VARIABLE FOR FRIDAY NIGHT - GRADUALLY RETURNING TO THE
SOUTHEAST AS THE WARM FRONT MOVES THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION....RIECK
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
353 AM PDT FRI MAY 15 2015
.SYNOPSIS...
A DISTURBANCE WILL CONTINUE SHOWERS AND ISOLATED THUNDERSTORMS
THROUGH THIS TODAY. LOCALLY HEAVY RAIN MAY PRODUCE FLASH
FLOODING...ESPECIALLY IN SAN DIEGO COUNTY. SNOW WILL FALL ABOVE
5500 TO 6000 FEET. THE SYSTEM WILL MOVE EAST OUT OF THE AREA
TONIGHT...AND FAIR BUT COOL WEATHER WILL OCCUR OVER THE WEEKEND
WITH AREAS OF MAINLY NIGHT AND MORNING LOW CLOUDS WEST OF THE
MOUNTAINS. A FEW SHOWERS ARE POSSIBLE NEXT MONDAY...BUT OTHERWISE
THE COOL WEATHER WITH AREAS OF COASTAL AND VALLEY LOW CLOUDS WILL
CONTINUE NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING
ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES...
AT 3 AM PDT...WATER VAPOR SATELLITE IMAGERY DISPLAYED A DEEP
UPPER-LEVEL LOW CENTERED JUST OFF THE COAST OF POINT CONCEPTION.
COMPOSITE RADAR IMAGERY SHOWED ISOLATED SHOWERS MOVING NORTHEAST
OVER PORTIONS OF THE COAST AND VALLEYS. AN UPDATED RAINFALL
TOTALS SUMMARY WAS ISSUED AT 215 AM. LINDBERGH FIELD IS THE WINNER
SO FAR AT 1.63 INCHES OF PRECIPITATION. MUCH OF THIS ACTUALLY FELL
IN A SHORT PERIOD AND CAUSED FLASH FLOODING IN PORTIONS OF THE
SAN DIEGO. THE 1.63 WAS ALSO A RECORD FOR LINDBERGH FOR THE
14TH...AND BLEW THE PREVIOUS RECORD OF 0.40 INCHES SET IN 1884 OUT
OF THE WATER.
ADDITIONAL PRECIPITATION REMAINS ON TRACK FOR SOUTHWEST CA FOR
TODAY. THE 15/0900 UTC HI-RES HRRR SHOWS THE NEXT WAVE MOVING
ACROSS THE AREA AS SOUTHERN CALIFORNIANS VENTURE OUT ON THEIR
MORNING COMMUTE. THE PLUME OF MOISTURE WILL BE SO DEEP IN THE
LOWER LEVELS THAT SHOWERS ARE FORECAST TO REACH THE DESERTS. LIGHT
TO MODERATE PRECIPITATION IS EXPECTED. HOWEVER...UNSTABLE AIR
ALOFT WILL ALLOW THE POSSIBILITY OF CONVECTION THIS MORNING AND
ESPECIALLY THIS AFTERNOON. STRONGER SHOWERS AND THUNDERSTORMS
COULD CREATE FLASH FLOODING AT TIMES...ESPECIALLY OVER/NEAR NEWER
BURN SCARS. A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS
AFTERNOON FOR PRONE AREAS. THE MAIN SURFACE LOW AND GREATEST AREAS
OF HEAVY SHOWERS WILL MOVE THROUGH THIS AFTERNOON...WITH SAN DIEGO
COUNTY HAVING THE BEST CHANCES OF PRECIPITATION. SNOW LEVELS THIS
MORNING ARE NEAR 5500 FT...AND WILL CLIMB THIS AFTERNOON TO NEAR
6500 FT. HIGHS TODAY WILL CHILLY FOR THIS TIME OF YEAR...RANGING
FROM 5 TO 10 DEGREES BELOW NORMAL ALONG THE COAST...AND 15 TO 30
DEGREES BELOW NORMAL INLAND.
...ADDITIONAL FORECAST PRECIP AMOUNTS THROUGH TONIGHT...
DESERTS.............0.05 TO 0.25 INCHES
COAST AND VALLEYS...0.50 TO 1.50 INCHES
MOUNTAINS...........0.50 TO 1.75 INCHES
...ADDITIONAL FORECAST SNOWFALL AMOUNTS THROUGH TONIGHT...
5500 TO 6500 FT...1 TO 2 INCHES
6500 TO 7500 FT...2 TO 4 INCHES
ABOVE 7500 FT.....4 TO 6 INCHES
THE WINTER WEATHER ADVISORY FOR PORTIONS OF THE SAN BERNARDINO
COUNTY AND RIVERSIDE COUNTY MOUNTAINS REMAINS IN EFFECT THROUGH
THIS AFTERNOON.
PRECIPITATION WILL QUICKLY END LATE TODAY AND OVERNIGHT AS THE
SYSTEM EJECTS EASTWARD. HIGH TEMPERATURES WILL WARM FEW DEGREES
EACH DAY THROUGH SUNDAY UNDER VERY WEAK RIDGING. HOWEVER...A DEEP
MARINE LAYER WILL REMAIN IN PLACE AND KEEP HIGH TEMPS CONTINUING
BELOW NORMAL FOR THIS TIME OF YEAR. ANOTHER LOW IS PROGGED TO MOVE
ACROSS CENTRAL CA MONDAY INTO TUESDAY. WITH LIMITED MOISTURE OVER
SOUTHERN CA...WIDESPREAD PRECIPITATION IS NOT ANTICIPATED AT THIS
TIME. CURRENTLY THERE IS A SLIGHT CHANCE OF PRECIP IN THE SAN
BERNARDINO COUNTY MOUNTAINS ON MONDAY. WEAK RIDGING BUILDS OVER
THE REGION TUESDAY NIGHT...THEN THE 15/0000 UTC ECMWF AND GFS
DIFFER IN THE PLACEMENT OF ANOTHER UPPER-LEVEL LOW ALONG THE WEST
COAST. THE GFS QUICKLY MOVES IT SOUTH ALONG THE COAST AND OVER THE
REGION EARLY THURSDAY...WHILE THE ECMWF IS SLOWER...PLACING THE
LOW OVER SW CA FRIDAY. FOR NOW...EXPECT BELOW NORMAL HIGH
TEMPERATURES AND A RELATIVELY DEEP MARINE LAYER NEXT WEEK.
&&
.AVIATION...
160949Z...WIDELY SCATTERED -SHRA CONTINUING THIS MORNING WITH MOSTLY
VFR CIGS/VIS PREVAILING. LOCAL MVFR CONDS POSSIBLE IN HEAVIER
SHOWERS. SHOWERS BECOMING HEAVIER AND MORE WIDESPREAD AFTER
12Z...WITH CIGS LOWERING TO 1500-2500 FT MSL AND VIS 2-4SM IN
SHOWERS...LOCALLY BLO 1000 FT MSL AND VIS DOWN TO 1SM. ISOLD TSRA
WITH SMALL HAIL ALSO POSSIBLE...MAINLY 16Z-02Z. SHOWERS TAPERING OFF
AFTER 16/02Z...ENDING OVERNIGHT. VARIABLE SCT-BKN CLOUD LAYERS AOA
2000 FT MSL AND COASTAL SLOPES OF THE MTNS OBSCURED TONIGHT INTO SAT
MORNING.
&&
.MARINE...
200 AM...A STORM SYSTEM WILL CONTINUE SHOWERS AND ISOLATED
THUNDERSTORMS OVER THE COASTAL WATERS THIS EVENING...INCREASING IN
COVERAGE LATER THIS MORNING. SMALL HAIL...GUSTY
WINDS...LIGHTNING...WATERSPOUTS...AND BRIEF HEAVY RAINFALL ARE
POSSIBLE WITH THUNDERSTORMS. A MARINE WEATHER
STATEMENT...LAXMWSSGX...REMAINS IN EFFECT. GUSTY NORTHWEST WINDS TO
25 KT WILL LIKELY DEVELOP BEHIND THE FRONT LATE THIS MORNING AND
CONTINUE THROUGH TONIGHT. CHOPPY SEAS AND HAZARDOUS CONDITIONS ARE
EXPECTED FOR SMALL CRAFT. A SMALL CRAFT ADVISORY REMAINS IN EFFECT
FROM FRIDAY MORNING THROUGH EARLY SAT MORNING. WINDS AND SEAS WILL
DIMINISH ON SATURDAY...WITH NO ADDITIONAL HAZARDOUS MARINE WEATHER
EXPECTED THROUGH TUESDAY.
&&
.SKYWARN...
SKYWARN ACTIVATION WILL LIKELY BE REQUESTED LATER THIS MORNING OR
EARLY THIS AFTERNOON.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR RIVERSIDE COUNTY
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN DIEGO COUNTY
COASTAL AREAS-SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY
VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
WINTER WEATHER ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT SATURDAY FOR WATERS FROM SAN
MATEO POINT TO THE MEXICAN BORDER EXTENDING 30 TO 60 NM OUT
INCLUDING SAN CLEMENTE ISLAND.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR COASTAL
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
TO 30 NM.
&&
$$
PUBLIC...JJT
AVIATION/MARINE...SS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
459 AM MDT FRI MAY 15 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 459 AM MDT FRI MAY 15 2015
COMPLEX SITUATION TODAY AS SOUTHERLY FLOW STRENGTHENS AHEAD OF
THE UPPER LOW OVER SOUTHERN NEVADA. BIGGEST QUESTION IS THE
POSITION OF LOW LEVEL FEATURES ON THE PLAINS THIS AFTERNOON AND
THE AMOUNT OF HEAT AND MOISTURE AVAILABLE FOR CONVECTION. SEVERAL
FACTORS ARE FAVORABLE FOR SEVERE WEATHER...MOST NOTABLY STRONG
SHEAR AND A PLUME OF MOISTURE PUSHING WESTWARD ON THE NORTH SIDE
OF A SURFACE LOW/TROUGH THAT WILL BE IN EASTERN COLORADO. IT IS
ALSO LOOKING LIKE THERE WILL BE ENOUGH DRY MID LEVEL AIR TO ALLOW
A FAIR AMOUNT OF SUN OVER NORTHEAST COLORADO TODAY...WHILE THE
WESTWARD EXTENT OF THE GOOD MOISTURE MAY BE A BIT MORE THAN
PREVIOUSLY EXPECTED. ALWAYS HARD TO SECOND GUESS JUST HOW MUCH
MIXING OUT OF THE MOISTURE THERE WILL BE...CERTAINLY WEST OF THE
DRY LINE THIS WILL HAPPEN...BUT ON THE NORTH SIDE OF THE LOW THE
PLUME OF MOISTURE WRAPPING AROUND WILL NOT MIX AS MUCH. BIGGEST
QUESTION IS PROBABLY THE SHARPNESS OF THE LOW/TROUGH FEATURE WHICH
IS OFTEN UNDERDONE IN THE MODELS. AT THIS HOUR THE HRRR IS SHOWING
A PLUME OF EAST WINDS HOLDING 50 DEGREE DEW POINTS AND CAPES
AROUND 2000 J/KG ALONG THE NORTHERN BORDER BACK AS FAR AS WELD
COUNTY. HOWEVER IT ALSO SCOURS OUT THE MOISTURE IN AREAS FURTHER
SOUTH...DRYING OUT WASHINGTON COUNTY BY MID AFTERNOON BEFORE THE
CONVECTION GETS GOING.
A NEGATIVE FACTOR MAY BE TOO MUCH SOUTHERLY WIND. THIS MAY HELP
DRY THINGS OUT AND PUSH THE BETTER MOISTURE TO THE NORTH...AND MAY
ALSO REDUCE THE SHEAR AND ESPECIALLY THE HELICITY IF THE WIND
PROFILE WINDS UP BEING PRETTY LINEAR. THERE SHOULD BE A SWEET SPOT
WITH THE LOW LEVEL WINDS BACKED TO EASTERLY...MOST LIKELY NEAR OUR
NORTHERN BORDER OR JUST INTO NEBRASKA. THIS AREA WOULD HAVE THE
BEST THREAT OF SEVERE WEATHER AND A DECENT TORNADO THREAT. WILL GO
WITH THIS IDEA AS THE MOST LIKELY SCENARIO...WITH STRONG STORMS
DEVELOPING IN THE MOISTURE ALONG THE DRY LINE AND/OR NORTH OF THE
LOW/TROUGH WHERE CAPES WILL BE 1500-2000 J/KG...THEN PROPAGATING
NORTH WITH THE SEVERE THREAT INCREASING NEAR OUR NORTHERN BORDER.
OTHER STORMS WILL FORM ON THE BACK EDGE OF THE DRY SLOT...NEAR THE
FRONT RANGE/CHEYENNE RIDGE BUT SHOULD BE WEAKER WITH CAPES OF 500
J/KG NEAR THE MOUNTAINS AND IMPROVING A BIT AS THEY MOVE EAST INTO
THE MOISTURE TONGUE. STILL COULD BE SOME SEVERE THREAT HERE AS
WELL...MAINLY IN NORTHERN WELD COUNTY. OF COURSE IF THE LOW WINDS
UP BEING BETTER DEFINED THERE WOULD BE A MUCH HIGHER THREAT OF
SEVERE WEATHER ON THE NORTH AND NORTHEAST SIDE OF THE LOW.
RAISED HIGHS A LITTLE EXPECTING MORE SUN...STILL A FEW DEGREES
BELOW GUIDANCE AND IF IT IS A LITTLE WARMER THAT WILL HELP AS
WELL. TRENDED POPS MORE TOWARD THE IDEA OF A GOOD BREAK IN THE DRY
SLOT MUCH OF TODAY...WITH STORMS MOVING IN FROM THE WEST AND
DEVELOPING IN THE NORTH AND EAST IN THE LATE AFTERNOON. BEST
COVERAGE PROBABLY IN THE EARLY EVENING ON THE PLAINS...BUT
INTESITY SHOULD BE LESS THEN. SOME CLOUDS AND WEAK SHOWERS HANG ON
OVERNIGHT WITH A LITTLE COOLING ALOFT AND OVERALL INCREASE IN
MOISTURE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM MDT FRI MAY 15 2015
OVERALL TREND IN THE FORECAST IS THE SAME. THE NEXT SYSTEM WILL
IMPACT THE CWA ON SATURDAY. THE BROAD BUT CLOSED UPPER TROUGH WILL
STRETCH FROM THE NORTHERN ROCKIES TO THE DESERT SOUTHWEST AT 12Z
SATURDAY...WITH A MODERATE TO STRONG SLY FLOW OVER EASTERN
COLORADO. WEAK TO MODERATE MID AND UPPER LEVEL QG ASCENT WILL
REMAIN OVER NORTHEAST COLORADO THROUGH THE DAY...WITH PLENTY OF
MOISTURE IN PLACE. MAIN ISSUE WILL BE WHERE THE SFC LOW SETS UP
AND AT THIS TIME IT APPEARS TO BE ALONG THE EASTERN BORDER. IF
THIS OCCURS...THEN THE STRONG/SEVERE THUNDERSTORMS WILL LIKELY BE
EAST OF COLORADO...BUT CANNOT RULE OUT ONE OR TWO REACHING SEVERE
LEVELS ALONG THE BORDER WHERE THE BEST VERTICAL SHEAR WILL BE
PRESENT. IN AND AROUND DENVER FORECAST CAPES IN THE AFTERNOON NOT
BAD...800-900 J/KG. MOISTURE AOA 700 MB IN THE AFTN...BUT DRIER IN
THE LOWER LEVELS. IN THE MOUNTAINS...NO HIGHLIGHTS BUT COULD SEE
UP TO 5 INCHES ABOVE 10 KT THROUGH THE DAY SATURDAY.
SATURDAY NIGHT INTO SUNDAY...THE QG ASCENT SHIFTS TO THE NORTH AND
EAST WITH INCREASING QG DESCENT OVER THE REGION. THE MID LEVEL
TROUGH AXIS SLIDES EASTWARD SATURDAY EVENING...WITH SUBSIDENCE
IN PLACE AS A SHORT WAVE RIDGE PUSHES INTO THE STATE THROUGH
SUNDAY. SOME LINGERING SHOWERS IN THE HIGH COUNTRY WEST OF THE
CONTINENTAL DIVIDE...BUT DOWNSLOPE IN AND NEAR THE FRONT RANGE
FOOTHILLS SHOULD NEGATE MUCH OF THE PCPN IN THE 03Z-06Z WINDOW.
FOR SUNDAY AFTERNOON...SHOWERS AND A FEW STORMS ARE PROGGED TO
DEVELOP AS MID LEVEL MOISTURE AND AFTN HEATING WILL OFFSET THE
INFLUENCE OF THE RIDGE.
SUNDAY NIGHT...A SURFACE HIGH IS PROGGED TO PUSH A COLD FRONT INTO
THE FRONT RANGE IN THE EVENING. LINGERING SHOWERS AND ISOLATED
THUNDERSTORMS WILL LINGER THROUGH SUNDAY EVENING. NOT MUCH IN THE
WAY OF PCPN FM 06Z-18Z MONDAY. THE UPPER RIDGE WILL SHIFT TO THE
EAST WITH THE FLOW ALOFT BECOMING SOUTHWESTERLY AHEAD OF THE NEXT
DEVELOPING TROUGH. MUCH OF THE SHOWER/TSTM ACTIVITY ON MONDAY
AFTN WILL OCCUR IN THE HIGH COUNTRY. MDLS STILL PEG ANOTHER GOOD
CHC OF PCPN FOR MUCH OF THE CWA LATE MONDAY NIGHT THROUGH TUESDAY
EVENING. A MOIST SOUTHERLY FLOW ALOFT AHEAD OF THIS TROUGH...
OVERRUNNING AND STATIONARY FRONTAL BOUNDARY SITTING ALONG THE
FRONT RANGE/PALMER DIVIDE. THIS BROAD TROUGH IS PROGGED TO LIFT
NORTHWARD TUESDAY NIGHT...BUT NOT ENOUGH TO DRY THE REGION OUT ON
WEDNESDAY/THURSDAY. BEST CHC OF SHOWERS/TSTMS THOSE DAYS APPEAR TO
BE FROM THE FRONT RANGE EASTWARD WHERE THE BEST MOISTURE WILL BE.
OVERALL TEMPERATURES WL REMAIN COOLER THAN NORMAL...COLDEST ON
SATURDAY AND THEN TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 459 AM MDT FRI MAY 15 2015
VFR THROUGH TONIGHT. THERE WILL LIKELY BE A PERIOD OF GUSTY SOUTH
WINDS SHIFTING TO THE NORTH OR WEST DURING THE AFTERNOON...POSSIBLY
WITH SOME VARIABLE THUNDERSTORM OUTFLOW WINDS AS WELL. GUSTS AS
HIGH AS 40 KNOTS ARE POSSIBLE. ANY DIRECT THUNDERSTORM IMPACTS
SHOULD BE SHORT LIVED...BUT THE VARIABLE WINDS COULD LAST SEVERAL
HOURS.
&&
.HYDROLOGY...
ISSUED AT 459 AM MDT FRI MAY 15 2015
RIVER LEVELS ARE STILL COMING UP FROM JUST EAST OF STERLING TO
JULESBURG AND WILL RISE TO RIGHT AROUND FLOOD STAGE. THE CACHE LA
POUDRE RIVER IN WELD COUNTY IS JUST ABOVE FLOOD STAGE AND THIS
WILL CONTINUE INTO SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GIMMESTAD
LONG TERM...COOPER
AVIATION...GIMMESTAD
HYDROLOGY...COOPER
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
635 AM EDT FRI MAY 15 2015
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH EARLY NEXT WEEK. A
COLD FRONT IS EXPECTED TO PUSH THROUGH THE REGION LATE TUESDAY
INTO WEDNESDAY AND POSSIBLY STALL NEAR OR SOUTH OF THE AREA. WEAK
HIGH PRESSURE IS EXPECTED TO RETURN THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FEW CHANGES WERE MADE WITH THE SUNRISE UPDATE BASED ON THE
LATEST HIGH RESOLUTION DATA...
* INTRODUCED SLIGHT CHANCE POPS FROM ROUGHLY WALTERBORO TO MONCKS
CORNER. BOTH THE RAP AND H3R HAVE COME IN LINE WITH THE EARLIER
RUNS OF THE NAM12 IN SHOWING ISOLATED SHOWERS/TSTMS FIRING IN
THIS AREA FOR A FEW HOURS THIS AFTERNOON WITHIN A BROAD
CONFLUENCE ZONE.
* GUIDANCE HAS PUSHED THE PRIMARY MOISTURE RETURN CHANNEL A BIT
FARTHER SOUTH SLIGHT CHANCE POPS WERE READJUSTED TO ONLY
INCLUDE AREAS FROM REIDSVILLE-LUDOWICI-DARIEN.
* NUDGED HIGH TEMPERATURES UP 1-2 DEGREES ACROSS FAR INTERIOR
SOUTHEAST GEORGIA.
DEEP LAYERED HIGH PRESSURE WILL REMAIN ANCHORED ATOP THE SOUTHEAST
U.S. AND DEEP SOUTH TODAY...ALTHOUGH SURFACE HIGH PRESSURE WILL
BEGIN TO MEANDER OFF THE MID-ATLANTIC COAST. THIS WILL ESTABLISH
A SOLID RETURN FLOW REGIME ACROSS THE DEEP SOUTH, ALTHOUGH MODELS
ARE SIMILAR IN KEEPING THE MAIN MOISTURE CONVEYOR DISPLACED JUST
TO THE SOUTH AND SOUTHWEST. ANY CHANCES FOR AN ISOLATED
SHOWER/TSTM WILL REMAIN CONFINED TO THE FAR SOUTHERN AND
SOUTHWESTERN PERIPHERY OF THE LOCAL FORECAST AREA; PRIMARY ALONG
AND SOUTHWEST OF A REIDSVILLE-DARIEN LINE. SLIGHT CHANCE POPS WILL
BE MAINTAINED IN THESE AREAS.
THE NAM12 HAS BEEN DEPICTING ISOLATED SHOWERS DEVELOPING ACROSS
THE CHARLESTON TRI-COUNTY AREA WITHIN WHAT APPEARS TO BE A BROAD
CONFLUENCE ZONE THAT A FORMS LATER THIS MORNING. IT IS UNCLEAR
WHETHER IS FEATURE WILL MATERIALIZE OR NOT, BUT THE LATEST H3R AND
RAP RUNS HAVE COME IN LINE WITH PREVIOUS NAM12 RUNS. INTRODUCED
SLIGHT CHANCE POPS FROM WALTERBORO-MONCKS CORNER TO COVER THIS.
THE DEEP ONSHORE FLOW WILL CURTAIL TEMPERATURES AGAIN TODAY.
HIGHS LOOK TO GENERALLY MAX OUT IN THE LOWER-MID 80S WITH MID-
UPPER 70S AT THE BEACHES. THIS IS SLIGHTLY BELOW NORMAL FOR MID-
MAY. THE VARIOUS 15/00Z MODELS SHOW SOME DEGREE OF CLEARING TAKING
PLACE LATER THIS AFTERNOON OR EARLY THIS EVENING, ESPECIALLY
ACROSS SOUTHEAST SOUTH CAROLINA. WILL ADJUST THE SKY FORECAST TO
SHOW A SLIGHTLY MORE OPTIMISTIC SKY CHARACTER DEVELOPING NORTH OF
THE SAVANNAH RIVER BY MID AFTERNOON TO TREND. CLOUDS LOOK TO HOLD
FOR MUCH OF THE DAY IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...DRY CONDITIONS WILL PREVAIL. ANY ISOLATED SHOWER/TSTM
ACTIVITY THAT DEVELOPS ACROSS THE FAR SOUTHERN AND SOUTHWESTERN
AREAS WILL DISSIPATE WITH THE LOSS OF INSOLATION. CLEARING WILL BE
ONGOING DURING THE EVENING HOURS WITH HIGH CLOUDS POSSIBLY
INCREASING AGAIN LATE AS THE MEAN UPPER LEVEL RIDGE AXIS SHIFTS
SLIGHTLY EAST. LOWS WILL RANGE FROM THE LOWER 60S INLAND WITH
UPPER 60S/NEAR 70 AT THE BEACHES.
SATURDAY AND SUNDAY...DEEP LAYERED RIDGING WILL PERSIST OVER THE
SOUTHEASTERN U.S. THROUGH THE WEEKEND. LACK OF SIGNIFICANT FORCING
AND A DECENT CAP NOTED IN MODEL SOUNDINGS WILL ALLOW FOR A MOSTLY
DRY FORECAST. THE EXCEPTION WOULD BE IN OUR FAR SOUTHERN ZONES IN
GEORGIA WHERE A BIT BETTER MOISTURE RESIDES. GIVEN THIS...HAVE
MAINTAINED A SLIVER OF SLIGHT CHANCE POPS IN THE FORECAST FOR THE
AFTERNOON/EVENING HOURS BOTH SATURDAY AND SUNDAY. HOWEVER
OVERALL...TRENDED POPS DOWNWARD AS LATEST GUIDANCE HAS COME IN
DRIER.
MONDAY...ATLANTIC HIGH PRESSURE WILL BEGIN TO WEAKEN AS A PRE-
FRONTAL TROUGH DEVELOPS AHEAD OF A COLD FRONT CROSSING THROUGH THE
OHIO AND MISSISSIPPI RIVER VALLEYS. INCREASING LOW LEVEL MOISTURE
WILL KEEP SLIGHT CHANCE/CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE
AFTERNOON AND EVENING. WEAK SHEAR AND MARGINAL INSTABILITY WILL KEEP
OVERALL SEVERE POTENTIAL PRETTY LOW...ALTHOUGH CANNOT RULE OUT A
STRONGER PULSE STORM IF BOUNDARIES INTERACT.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. HIGHS
AWAY FROM THE COAST IN THE MID 80S SATURDAY WILL WARM TO THE UPPER
80S/AROUND 90 BY MONDAY. LOWS WILL BE QUITE MILD MAINLY IN THE MID
TO UPPER 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
MODELS ARE IN DECENT AGREEMENT IN THE LONG TERM PERIOD. A COLD
FRONT WILL APPROACH THE REGION TUESDAY...CROSSING THROUGH THE
LOCAL AREA LATE TUESDAY NIGHT INTO WEDNESDAY. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF AND ALONG THE FRONT. THE
FRONT MAY THEN STALL NEAR OR SOUTH OF THE AREA WHILE WEAK HIGH
PRESSURE BUILDS IN FROM THE NORTHWEST FOR LATE WEEK. TEMPERATURES
WILL REMAIN NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR. CIGS APPROACHING UPPER END OF MVFR THRESHOLDS ARE POSSIBLE
AFTER SUNRISE AT KCHS, ROUGHLY 13-16Z, BUT LOOK TO REMAIN VFR FOR
NOW.
EXTENDED AVIATION OUTLOOK...GENERALLY VFR CONDITIONS EXPECTED TO
PREVAIL THROUGH THE WEEKEND. FLIGHT RESTRICTIONS POSSIBLE WITHIN
AFTERNOON/EVENING THUNDERSTORMS EARLY NEXT WEEK.
&&
.MARINE...
TODAY...STILL SEEING SEAS OF 6 FT IN THE GEORGIA OFFSHORE WATERS
SO A SMALL CRAFT ADVISORY WILL REMAIN IN FORCE FOR THAT LEG UNTIL
11 AM. OTHERWISE, ONSHORE WINDS WILL PERSIST TODAY AS HIGH
PRESSURE ALONG THE MID-ATLANTIC COAST SHIFTS OFFSHORE IN THE
WESTERN ATLANTIC. EAST WINDS WILL GRADUALLY BECOME SOUTHEAST AS A
RESULT...BUT SPEEDS WILL GENERALLY REMAIN 15 KT OR LESS. SEAS WILL
SUBSIDE BY ABOUT A FOOT BY THIS AFTERNOON SETTLING INTO THE 2-3 FT
RANGE NEARSHORE WATERS AND A SOLID 4 FT OFFSHORE WATERS.
TONIGHT...SOUTHEAST WINDS OF 10-15 KT WILL PERSIST AS HIGH
PRESSURE SHIFTS EVEN FARTHER OFFSHORE. SEAS WILL REMAIN 2-3 FT
NEARSHORE WATERS WITH 3-4 FT OFFSHORE WATERS.
SATURDAY THROUGH WEDNESDAY...MARINE CONDITIONS WILL REMAIN RATHER
BENIGN OVER THE WEEKEND AS SURFACE HIGH PRESSURE REMAINS ANCHORED
OVER THE ATLANTIC. EAST/SOUTHEAST WINDS EXPECTED TO BE 15 KT OR LESS
WITH SEAS 2-4 FEET ON AVERAGE THROUGH SUNDAY. MONDAY...WINDS WILL
VEER MORE TO THE SOUTH/SOUTHWEST AS THE SURFACE HIGH GETS SUPPRESSED
SOUTH. A COLD FRONT WILL APPROACH THE REGION TUESDAY AND CROSS THE
WATERS LATE TUESDAY/EARLY WEDNESDAY. NORTHEAST WINDS WILL PICK UP
BEHIND THE FRONT WEDNESDAY HOWEVER CONDITIONS LOOK TO REMAIN UNDER
HEADLINE CRITERIA AT THIS TIME.
RIP CURRENTS...SECONDARY SWELL IS FORECAST TO INCREASE TO PERIODS
OF 8-9 SECONDS TODAY. THESE LONGER PERIODS WILL AFFECT THE SOUTH
CAROLINA BEACHES FIRST THE SPREAD DOWN THE COAST AS THE DAY
PROGRESSES. LONG PERIODS COMBINED WITH STRONG OUTGOING TIDES DUE
TO ALREADY ELEVATED TIDE LEVELS AND INCREASING INFLUENCES FROM
THE APPROACHING LUNAR PERIGEE WILL SUPPORT A RISK FOR MORE
FREQUENT RIP CURRENTS TODAY. A MODERATE RISK FOR RIP CURRENTS WILL
BE POSTED FOR ALL BEACHES THROUGH EARLY THIS EVENING.
&&
.TIDES/COASTAL FLOODING...
TIDE LEVELS WILL COME CLOSE TO CLOSE TO 7.0 FT MLLW IN THE
CHARLESTON HARBOR WITH HIGH TIDE EARLY THIS EVENING. A COASTAL
FLOOD ADVISORY MAY BE NEEDED FOR MAINLY THE SOUTH CAROLINA COASTAL
ZONES LATER TODAY IF CURRENT TIDE TRENDS CONTINUE.
ONSHORE WINDS COMBINED WITH INFLUENCES FROM THE LUNAR PERIGEE
WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL
TIDES THIS WEEKEND. SHALLOW COASTAL FLOODING WILL BE POSSIBLE
AROUND TIMES OF HIGH TIDE SATURDAY AND SUNDAY...ESPECIALLY ACROSS
SOUTH COASTAL SOUTH CAROLINA.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ374.
&&
$$
ST/ECT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
620 AM EDT FRI MAY 15 2015
.SYNOPSIS...
DRY WEATHER THIS AFTERNOON UNDER HIGH PRESSURE AT THE SURFACE AND
ALOFT. THE CHANCE FOR RAIN WILL INCREASE SLIGHTLY THROUGH THE
WEEKEND AS MOISTURE RETURNS TO THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER RIDGE AXIS EXTENDING FROM THE WESTERN ATLANTIC NORTH
THROUGH THE CAROLINAS TO THE EASTERN GREAT LAKES. SURFACE HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC COAST. ATMOSPHERIC
MOISTURE GRADIENT ACROSS THE REGION WITH DRIER AIR TO THE EAST AND
MORE MOISTURE TO THE WEST. UPPER IMPULSE CURRENTLY MOVING SLOWLY
EAST ACROSS THE WESTERN CAROLINAS AND GEORGIA. ..AND WILL MOVE
SLOWLY EAST THROUGH THE RIDGE AXIS ACROSS OUR FA LATER THIS
MORNING AND TO OUR EAST BY THIS AFTERNOON. A FEW LIGHT SHOWERS
POSSIBLE THIS MORNING AHEAD OF THE UPPER IMPULSE. LATER
TODAY...MODEL FOECAST SOUNDINGS INDICATE MID LEVEL CAPPING DUE TO
THE UPPER RIDGE AXIS AND GENERALLY LIMITED MOISTURE OVER MOST OF
THE FA. HOWEVER...DIURNAL HEATING MAY PROVIDE A CATALYST FOR SOME
ISOLATED TO WIDELY SCATTERED SHALLOW SHOWER ACTIVITY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BE OVER THE WESTERN ATLANTIC WITH
SOUTHEASTERLY FLOW PUSHING MOISTURE BACK INTO THE REGION. BEST
INSTABILITY WILL BE ACROSS THE UPSTATE. MAJORITY OF THE CWA WILL
REMAIN DRY THROUGH THE PERIOD. AFTERNOON HIGH TEMPERATURES WILL BE
IN THE MID 80S SATURDAY AND OVERNIGHT LOWS IN THE LOW TO MID 60S
EACH NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH A HIGHLY
AMPLIFIED PATTERN DOMINATING THE COUNTRY. THIS WILL KEEP AN UPPER
LEVEL RIDGE OVER THE EASTERN US WITH MOIST SOUTHERLY FLOW
PERSISTING OVER THE FORECAST AREA THROUGH THE MIDDLE OF THE WEEK.
EXPECTING MAINLY DIURNAL SHOWER/STORM ACTIVITY THROUGH A MAJORITY
OF THE PERIOD. A WEAK FRONTAL BOUNDARY WILL STRUGGLE TO CROSS THE
REGION ON WEDNESDAY WITH MODELS INDICTING THE FRONT SHEARING APART
AND STALLING OVER THE REGION FOR THURSDAY. WITH THE RUN TO RUN
CONSISTENCY OF THE LONG TERM MODELS CHANGES TO THE FORECAST HAVE
BEEN MINOR. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY TO
ABOVE NORMAL.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS ACROSS THE CSRA...WITH MVFR VSBYS AT CAE/CUB. EXPECT
MVFR CIGS AND/OR VSBYS IN THE NEAR TERM. LATEST HRRR KEEPS LOWER
CIGS MAINLY NEAR THE CSRA IN THE NEAR TERM. DIURNAL HEATING
EXPECTED TO PROVIDE A RETURN TO VFR BY AFTERNOON. A FEW SHOWERS
WILL BE POSSIBLE BUT CHANCES NOT SUFFICIENT TO INCLUDE MENTION IN
THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN DIURNAL
CONVECTION THROUGH THE WEEKEND.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BOISE ID
956 AM MDT FRI MAY 15 2015
.DISCUSSION...SHOWERS CONTINUE TO MOVE FROM SE TO NW ACROSS MUCH
OF THE CWA THIS MORNING. WE EXPECT MODERATE TO HEAVY RAIN THIS
AFTERNOON OVER THE WEST CENTRAL MTNS AND ALSO THE HIGHER TERRAIN
OF SE OREGON. OVERNIGHT...THE OBSERVING SITE NEAR ROME OREGON
(KREO) REPORTED OVER AN INCH OF RAIN. WE HAVE SLIGHTLY REDUCED
TEMPERATURES IN AREAS WHERE CLOUDS ARE EXPECTED TO BE THE MOST
CONSISTENT...AND SLIGHTLY RAISED THEM IN THE SOUTHEAST NEAR TWIN
FALLS AND JEROME WHERE SKIES WILL SEE SOME CLEARING. UPDATE OUT
SHORTLY.
&&
.AVIATION...MOSTLY VFR. BROKEN TO OVERCAST LOW VFR CLOUDS WITH
WIDESPREAD SHOWERS...ISOLATED THUNDERSTORMS THIS AFTERNOON. AREAS
OF MOUNTAIN OBSCURATION WITH LOCAL MVFR CONDITIONS IN HEAVIER
SHOWERS. SURFACE WINDS GENERALLY 12 KNOTS OR LESS WITH GUSTY WINDS
NEAR THUNDERSTORMS. WINDS ALOFT SOUTHEASTERLY AROUND 10 KNOTS UP
THROUGH 10K FEET MSL.
WEEKEND OUTLOOK...SHOWERS WITH AFTERNOON/EVENING THUNDERSTORMS WILL
CONTINUE THROUGH THE WEEKEND. CEILINGS EXPECTED TO REMAIN LOW VFR
ALONG WITH AREAS OF MOUNTAIN OBSCURATION. LOCAL MVFR CONDITIONS IN
HEAVIER SHOWERS.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH SATURDAY...NUMEROUS SHOWERS ARE
LIFTING FROM THE SE TO THE NW ACROSS SW IDAHO AND SE
OREGON...GENERALLY IN AN ARC FROM THE STEENS MTN OREGON TO
FAIRFIELD IDAHO. SOUTH OF THIS AREA IS A BIT OF A DRY SLOT OVER NE
NV. HRRR LIFTS THE ARC TO THE NW THIS MORNING THEN SLOWS IT
TOWARDS NOON OVER BAKER COUNTY...AND BREAKS OUT MORE SHOWERS IN
THE DRY SLOT AS IT LIFTS ACROSS SW ID AND JORDAN VALLEY. CALIBRATED
SREF SHOWS GREATEST THUNDERSTORM THREAT ACROSS SW IDAHO THIS
AFTERNOON AND EVENING. PWAT IN THE 70-80TH PERCENTILE THROUGH THE
SHORT TERM AS UNSETTLED WEATHER WITH SHOWERS AND LATE DAY
THUNDERSTORMS CONTINUE OVER IDAHO ESPECIALLY. TEMPERATURES AVERAGE
AROUND 5 TO 10 DEGREES BELOW NORMAL IN THE SHORT TERM.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...MODELS CONTINUE TO
SHOW AN ACTIVE AND WET PATTERN AS A BROAD TROUGH CONTINUES TO
DOMINATE THE MID AND LONG TERM. A SERIES OF CLOSED LOWS ARE
EXPECTED TO MOVE SOUTH ALONG THE PACIFIC COAST CONTINUING THE
CHANCE OF SHOWERS AND AFTERNOON THUNDERSTORMS. HEAVIER BANDS OF
PRECIP AND BRIEF DRY PERIODS WILL EXIST...BUT POPS REFLECT AN
OVERALL UNSETTLED FORECAST. TEMPERATURES ARE EXPECTED TO REMAIN
WITHING 5 DEGREES OF NORMAL THROUGH THE PERIOD.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...SP
AVIATION.....JA
PREV SHORT TERM...VM
PREV LONG TERM....EP
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1026 AM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1025 AM CDT FRI MAY 15 2015
CLUSTERS OF SHOWERS/STORMS ACROSS THE SOUTHEAST THIRD OF THE CWA
HAVE LARGELY EXITED THE AREA...HOWEVER REGIONAL RADAR SHOWS SOME
WIDELY SCATTERED SHOWERS EXTENDING SOUTHWEST FROM THERE TOWARD THE
SOUTHERN ST. LOUIS METRO ALONG THE EDGE OF A NARROW CLEAR SLOT.
MAIN FRONTAL BOUNDARY CONTINUES TO LIFT NORTHWARD AND MOST OF THE
CWA NOW HAS DEW POINTS WELL INTO THE 60S. SOME LOW CLOUDS HAVE
BEEN PERSISTING ACROSS THE ILLINOIS RIVER VALLEY...ALTHOUGH
CEILINGS SHOULD RISE OVER THE NEXT COUPLE HOURS.
MAIN CHALLENGE FOR TODAY IS WITH TIMING OF REDEVELOPMENT. UPPER
WAVE ACROSS THE CENTRAL PLAINS EXPECTED TO TRACK INTO WESTERN
MISSOURI LATER TODAY...WITH THE NAM AND HRRR BOTH DEVELOPING
CONVECTION BY MID AFTERNOON. HOWEVER...THE HRRR ALSO LIFTS
CONVECTION CURRENTLY IN SOUTHERN MISSOURI/NORTHERN ARKANSAS
NORTHWARD AND BRINGS IT NEAR A JACKSONVILLE TO EFFINGHAM LINE BY
MID AFTERNOON. THE PREVIOUS AFTERNOON POP GRIDS HAD THAT
PARTICULAR SCENARIO ALREADY IN PLACE...AND RECENT UPDATES
CONTINUED THAT GENERAL TREND EXCEPT TO INCREASE THE POP`S A BIT
MID/LATE AFTERNOON.
&&
.SHORT TERM...(TODAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
07Z/2AM SURFACE ANALYSIS SHOWS A 1012MB LOW OVER WESTERN
WISCONSIN...WITH A WARM FRONT ARCING SOUTHEASTWARD INTO NORTH-
CENTRAL ILLINOIS. SURFACE WINDS AT ALL KILX OB SITES HAVE VEERED TO
THE S/SW...SO THINK FRONT IS NOW JUST NORTH OF THE AREA ALONG A
MOLINE TO KANKAKEE LINE. WIDELY SCATTERED SHOWERS CONTINUE SOUTH OF
THE FRONT...ALTHOUGH RADAR IS SHOWING A DISTINCT DIMINISHING TREND.
WITH WARM FRONT LIFTING FURTHER NORTHWARD THIS MORNING...FORCING FOR
ADDITIONAL CONVECTION WILL BE WEAK. AS A RESULT...THINK ONLY
ISOLATED SHOWERS/THUNDER WILL BE PRESENT ACROSS THE AREA THROUGH
MIDDAY. AS THE DAY PROGRESSES...A WEAK SHORT-WAVE TROUGH NOTED ON
LATEST WATER VAPOR IMAGERY OVER TEXAS WILL APPROACH FROM THE
SOUTHWEST...PROVIDING ENHANCED LIFT AND GREATER AREAL COVERAGE OF
CONVECTION. 4KM WRF-NMM SHOWS SCATTERED SHOWERS/THUNDER DEVELOPING
IN ADVANCE OF THE WAVE ACROSS MISSOURI BY EARLY AFTERNOON...THEN
SPREADING ACROSS THE SOUTHERN HALF OF THE CWA BY MID TO LATE
AFTERNOON. HAVE FASHIONED THE POPS ACCORDINGLY...FEATURING ONLY
ISOLATED SHOWERS/THUNDER ALONG AND NORTH OF I-74...WITH SCATTERED
WORDING FURTHER SOUTH ACROSS THE REMAINDER OF THE AREA. WILL BE A
WARM AND HUMID DAY...WITH AFTERNOON HIGH TEMPERATURES TOPPING OUT IN
THE UPPER 70S AND LOWER 80S.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
TEXAS WAVE WILL TRACK THROUGH THE AREA TONIGHT...TRIGGERING WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS. DESPITE MODEST LIFT ASSOCIATED
WITH THIS FEATURE...WILL ONLY CARRY LOW CHANCE POPS AS DAYTIME
INSTABILITY WANES. ANOTHER SHORT-WAVE EMBEDDED WITHIN THE DEEP
SOUTHWESTERLY FLOW PATTERN WILL APPROACH FROM THE SOUTHWEST ON
SATURDAY...WITH MODELS DISAGREEING ON HOW MUCH PRECIP IT WILL
GENERATE. MOST MODELS HAVE BEEN SHOWING THIS FEATURE TRACKING
TOWARD THE OHIO RIVER VALLEY FOR THE PAST FEW RUNS...WHICH WOULD
MEAN THE STRONGEST LIFT AND HIGHEST RAIN CHANCES WOULD BE FOCUSED
ACROSS THE SOUTHEAST CWA. LATEST NAM HAS STRAYED FROM THAT THINKING
AND NOW SPREADS QUITE A BIT OF PRECIP ACROSS THE ENTIRE AREA. HAVE
REJECTED THIS SOLUTION IN FAVOR OF THE CONSENSUS...WHICH STILL KEEPS
THE MAIN INFLUENCE OF THE WAVE FURTHER SOUTHEAST. AS A
RESULT...WILL FOCUS LIKELY POPS ALONG/SOUTH OF I-70 ON SATURDAY WITH
CHANCE POPS FURTHER NORTH AND WEST.
WESTERN CONUS UPPER LOW IS STILL EXPECTED TO TRACK INTO THE NORTHERN
PLAINS BY SUNDAY...WITH TRAILING COLD FRONT TRIGGERING WIDESPREAD
SHOWERS AND THUNDERSTORMS. MOST MODELS INDICATE STRONG/SEVERE
CONVECTION ACROSS NEBRASKA/KANSAS/OKLAHOMA SATURDAY AFTERNOON AND
EVENING...WITH STORMS TRACKING EASTWARD AND WEAKENING AS THEY
APPROACH THE MISSISSIPPI RIVER OVERNIGHT. THINK REMNANT
SHOWERS/THUNDERSTORMS WILL SPILL INTO WEST-CENTRAL ILLINOIS SUNDAY
MORNING BEFORE DISSIPATING TOWARD MIDDAY. ADDITIONAL DEVELOPMENT
WILL BE LIKELY LATER IN THE DAY...HOWEVER DEGREE OF
DESTABILIZATION IS IN QUESTION DUE TO CLOUD DEBRIS FROM THE
MORNING PRECIP. WITH SURFACE DEWPOINTS WELL INTO THE 60S...ANY
AMOUNT OF HEATING WILL EASILY CREATE SBCAPES OF 1500 TO 2500J/KG.
IN ADDITION...0-6KM BULK SHEAR WILL INCREASE TO OVER 40KT AS THE
WESTERN TROUGH APPROACHES. STILL DIFFICULT TO PIN DOWN EXACT
SEVERE WEATHER THREAT...HOWEVER THINK THUNDERSTORMS WILL BE LIKELY
WITH A FEW POSSIBLY BECOMING SEVERE DURING THE AFTERNOON AND
EVENING. MAIN THREATS WOULD BE DAMAGING WIND GUSTS AND LARGE
HAIL.
WHILE ACTUAL COLD FRONT REMAINS WELL TO THE WEST...MOST
MODELS SUGGEST THE MAIN BAND OF ACTIVE CONVECTION WILL SHIFT E/SE
INTO THE OHIO RIVER VALLEY SUNDAY NIGHT. WILL THEREFORE CONFINE
CHANCE POPS TO AREAS EAST OF THE I-55 CORRIDOR. FRONT WILL PUSH
THROUGH THE AREA ON MONDAY...WITH POTENTIAL RE-DEVELOPMENT OF
STORMS ALONG THE BOUNDARY LATER IN THE DAY. WILL HANG ON TO LOW
CHANCE POPS ACROSS THE FAR E/SE ACCORDINGLY...HOWEVER IT APPEARS
GREATEST CHANCE FOR ADDITIONAL THUNDER WILL BE FURTHER EAST INTO
INDIANA AND KENTUCKY.
ONCE THE FRONT PASSES...UNSEASONABLY STRONG CANADIAN HIGH PRESSURE
WILL SETTLE INTO THE REGION NEXT WEEK. WITH 850MB TEMPS PROGGED TO
DROP INTO THE SINGLE DIGITS...CORRESPONDING HIGHS WILL FALL BACK
INTO THE 60S AND LOWS WILL DIP INTO THE 40S TUESDAY THROUGH
THURSDAY. A WEAK UPPER-LEVEL WAVE WILL TRY TO APPROACH FROM THE
WEST BY MID-WEEK...BUT THINK IT WILL HAVE LITTLE IMPACT ON THE
WEATHER DUE TO THE COOL/DRY AIRMASS ACROSS THE REGION. GFS IS
AGGRESSIVELY PUSHING SHOWERS INTO THE AREA WEDNESDAY/WEDNESDAY
NIGHT...BUT AM GOING WITH A DRY FORECAST AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 648 AM CDT FRI MAY 15 2015
PREDOMINANTLY QUIET/VFR AVIATION WEATHER FORECAST EXPECTED ACROSS
THE CENTRAL ILLINOIS TERMINALS THROUGH THE 12Z TAF VALID TIME. A
WARM FRONT HAS LIFTED NORTH OF THE REGION OVERNIGHT, WITH SOUTH
TO SOUTHWEST WINDS ANTICIPATED THROUGH THE PERIOD. A WEAK UPPER
LEVEL DISTURBANCE WILL LIFT ACROSS THE AREA LATE THIS EVENING INTO
TONIGHT, POSSIBLY ACCOMPANIED BY A FEW SHOWERS/STORMS.
PRECIPITATION COVERAGE SHOULD BE LOW, AND CONFIDENCE IN THE
EXPLICIT TIMING IS NOT HIGH. SO, HAVE ONLY GONE WITH A VCSH
MENTION DURING THE NIGHTTIME HOURS. IF A HEAVIER SHOWER/STORM
IMPACTS A TERMINAL, MVFR CONDITIONS ARE POSSIBLE TONIGHT, BUT
OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
958 AM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 958 AM CDT FRI MAY 15 2015
CLEANED UP GRIDS A BIT FROM THE FOG THIS MORNING AND ADJUSTED
SKY/TEMPS ACCORDINGLY. ALSO MAY SEE A BIT COOLER MAX TEMPS ACROSS
THE NORTH WITH SOME ADDED IN CIRRUS FROM A FEW POP UP
THUNDERSTORMS ACROSS NORTHWEST IOWA...SO ADJUSTED NORTHERN CWA
TEMPS DOWN A BIT. LINE OF STORMS ALREADY ACROSS ERN NE ON NOSE OF
THETA-E ADVECTION WHICH IS EXPECTED TO BE ORIENTED MORE INTO
SOUTHERN/WESTERN CWA BY THIS AFTERNOON. THEREFORE DID INCREASE
POPS A BIT IN THAT REGION AND ACROSS THE SOUTH FOR THIS EVENING.
&&
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/12Z
ISSUED AT 643 AM CDT FRI MAY 15 2015
VSBYS FM FOG AND AREAS OF DENSE FOG WILL CONTINUE TO IMPROVE THROUGH
15Z. AFT 15Z WE SHOULD HAVE BKN VFR/MVFR CIGS INTO THE AFTERNOON.
A WARM FRONT WILL LIFT TO ABOUT HIGHWAY 20 THIS AFTERNOON. STORMS
WITH THIS FEATURE ARE NOT ANTICIPATED AT KDSM/OTM AND KFOD UNTIL AFT
21Z AND MAY NOT BE UNTIL AFT 00Z. SFC WIND WILL BE LGT AND VRB
BECOMING SOUTHERLY AROUND 10 KTS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...BEERENDS
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
644 AM CDT FRI MAY 15 2015
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/12Z
ISSUED AT 643 AM CDT FRI MAY 15 2015
VSBYS FM FOG AND AREAS OF DENSE FOG WILL CONTINUE TO IMPROVE THROUGH
15Z. AFT 15Z WE SHOULD HAVE BKN VFR/MVFR CIGS INTO THE AFTERNOON.
A WARM FRONT WILL LIFT TO ABOUT HIGHWAY 20 THIS AFTERNOON. STORMS
WITH THIS FEATURE ARE NOT ANTICIPATED AT KDSM/OTM AND KFOD UNTIL AFT
21Z AND MAY NOT BE UNTIL AFT 00Z. SFC WIND WILL BE LGT AND VRB
BECOMING SOUTHERLY AROUND 10 KTS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-
DALLAS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-
HARDIN-HUMBOLDT-JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-
TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS TOPEKA KS
642 AM CDT Fri May 15 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 328 AM CDT FRI MAY 15 2015
A broad upper level low was slowly pushing east across southern CA
into southwest AZ. A minor lead upper level trough was lifting
northeast across west TX into western OK. This trough was providing
ascent for a complex of thunderstorms to develop across southwest OK
and west central TX early this morning. This lead upper level trough
will lift northeast into northeast OK and southeast KS later this
morning.
A lee surface trough was deepening across the central and southern
high plains. Southerly 850mb winds were advecting deeper moisture
northward across central and west central KS. The isentropic lift
was deep enough for elevated storms to develop across north central
KS. These storms were lifting north-northeast and may develop
eastward into the western counties of the CWA through the mid
morning hours. The stronger storms may produce small hail.
The GFS, RAP and WRF models show the minor wave over west central
TX/southwest OK lifting northeast and providing enough ascent along
with the deeper moisture return for scattered showers and
thunderstorms to develop across the southern counties of the CWA
during the late morning hours, and spreading northeast across east
central and northeast KS during the early afternoon hours. However
the NAM12 and HRRR show most of the the thunderstorms remaining
across the western and northern counties of the CWA this morning. I
went with chance pops across the western and southern counties this
morning with chance pops across the northeast counties this
afternoon. The vertical wind shear Today looks rather weak with only
20 to 30 KTS of SFC to 6KM effective shear across the CWA. Several
numerical models show 1500-2000 J/KG of MLCAPE developing across the
CWA, thus some of the thunderstorms this afternoon across the
northern half of the CWA may be strong to marginally severe this
afternoon. The primary hazards would be penny to quarter hail and 50
to 60 MPH wind gusts. Highs Today will range from the upper 70s to
lower 80s with mostly cloudy skies.
Tonight, the amplified upper level low will move east across UT and
the four corners region. A strong mid level jet max will move
northeast across NM into eastern CO. The minor H5 trough across
southeast KS and southwest MO this afternoon will move northeast
across central MO. The intense isentropic lift will develop
northward across the northern plains and upper Midwest. The CWA will
remain dry through most of the night. Stronger ascent across western
KS will cause elevated thunderstorms to develop late tonight. Some
of these thunderstorms may move into the western counties of the CWA
before day break. These elevated storms may be strong to severe with
the primary hazard being large hail. Overnight lows will only drop
into the mid 60s.
.LONG TERM...(Saturday through Thursday)
Issued at 328 AM CDT FRI MAY 15 2015
Forecast focus remains on impact of intense upper system that will
emerge into the Plains Saturday into Saturday night.
All models appear to be converging on the most likely scenario on
Saturday which is that severe thunderstorms will develop near and
east of a dryline from Dodge City north toward Goodland after 20z
Saturday. Storms will quickly intensify and race NE at 50 to 60
mph which could bring them into parts of central Kansas by 6pm to
7pm Saturday. If sufficient buoyancy/instability is present...low level
shear and deep shear of 20-30kts and 50-60kts respectively would
provide an environment capable of supporting all manner of hazards
with the storms.
The wild card in this forecast remains how much
morning elevated convection will develop across OK into KS. We
continue to see a signal from various models that some convection
will develop Saturday morning within the weakly capped warm
sector. This is plausible since forcing will increase in advance
of the upper trough so we could see some impact on destabilization
across parts of the area through midday if this occurs. This makes
the scenario on Saturday difficult to pin down at this point with
regard to magnitude of the risk. In any case...forcing...shear
profiles and potential instability suggest this has the potential
to be a high impact event for parts of the area Saturday evening
and will highlight that everyone needs to monitor this especially
given all of the outdoor activities this weekend.
The dry slot will work into the area Sunday with gusty southwest
winds and warm temps. Instability axis should shift east of the
area so will keep conds dry on Sunday pm. The cold front will
sweep through the area Sunday night bringing much cooler and drier
air into the area for Monday and Tues. Only a brief break before
the next wave will move into the region with more rain expected
for later Tues into early Thurs. Trends suggest that the
severe risk with this system should stay south of the area so look
for another widespread rain with isolated thunder with this system.
&&
.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 640 AM CDT FRI MAY 15 2015
Patchy fog has been noted at FOE/TOP this morning, so have opted to
keep a tempo group with lower visbys until winds pick up around
15Z. Have included VCTS at all sites beginning later this morning
until 00Z, however, confidence with the exact timing/location of
these storms is low. There is another chance for lower
ceilings/visibilities tomorrow morning.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS JACKSON KY
1155 AM EDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1155 AM EDT FRI MAY 15 2015
AREA OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS IN EASTERN PART
OF FORECAST AREA WILL EXIT THE STATE BY 2 PM. HRRR CONTINUES TO
SHOW ISOLATED CONVECTION IN THE AFTERNOON...AND WILL CONTINUE WITH
THIS IN THE CURRENT FORECAST. HAVE UPDATED NDFD BASED ON LATEST
OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 926 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON LATEST RADAR AND
OBSERVATIONAL TRENDS. CURRENTLY A LINE OF SHOWERS WITH A FEW
THUNDERSTORMS IS MOVING ACROSS THE NW PART OF THE FORECAST AREA.
HAVE TIMED THIS ACROSS THE FORECAST AREA BASED ON CURRENT MOVEMENT
AND EXPECTED DIMINISHING TREND. HRRR SEEMS TO BE HANDING THIS
PRETTY GOOD...AND ONCE THIS MOVES OUT EXPECT A LULL BEFORE
ISOLATED CONVECTION BEGINS TO POP UP THIS AFTERNOON.
UPDATE ISSUED AT 715 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
RADAR TRENDS. ISOLATED SHOWERS AND EVEN A STRAY THUNDERSTORM AS
WELL AS SOME SPRINKLES WILL WORK ACROSS THE NORTHERN HALF TO TWO
OF THE AREA AS A SHORTWAVE WORKS THROUGH THE REGION. ADDITIONAL
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 15 2015
EARLY THIS MORNING...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS
CENTERED JUST EAST OF THE FLORIDA PENINSULA WITH SHORTWAVE
RIDGING NORTH ALONG THE EASTERN SEABOARD AND ANOTHER SHORTWAVE
RIDGE NORTHWEST INTO PARTS OF THE CENTRAL AND NORTHERN PLAINS. IN
BETWEEN...A SHORTWAVE TROUGH WAS WORKING TOWARD THE GREAT LAKES
AND ACROSS PARTS OF THE OH VALLEY AS IT MOVES AROUND THIS RIDGE.
FURTHER TO THE WEST...A TROUGH WAS MOVING INTO THE WESTERN CONUS.
THE SHORTWAVE WORKING ACROSS THE REGION AND THE ASSOCIATED SFC
SYSTEM WARM FRONT THAT IS GRADUALLY LIFTING NORTH ACROSS THE AREA
HAVE BROUGHT INCREASING MOISTURE THROUGH THE ENTIRE COLUMN TO THE
REGION. THIS HAS MAINLY BEEN REALIZED IN MID AND HIGH CLOUDS SO
FAR AND WARMER TEMPERATURES ATTM COMPARED TO 24 AND 48 HOURS AGO
DUE TO HIGHER SFC DEWPOINTS AND THE CLOUD COVER.
THE SHORTWAVE WILL MOVE INTO THE EASTERN GREAT LAKES AND MOVE
EAST OF THE AREA THIS MORNING...WITH SHORTWAVE RIDGING PROGGED TO
WORK ACROSS THE AREA FROM MIDDAY INTO THE EARLY EVENING. BEHIND
THE WARM FRONT...PW IS PROGGED TO BE IN THE 1.1 TO 1.3 INCH RANGE
OR SO. THE RIDGE AXIS IS EXPECTED TO MOVE EAST OF THE AREA
TONIGHT WITH THE REGION IN SOUTH TO SOUTHWEST FLOW ALOFT THROUGH
THE END OF THE PERIOD. WEAK SHORTWAVES WILL LIKELY MOVE ACROSS THE
AREA IN THIS FLOW AT TIMES FROM THIS EVENING OR TONIGHT THROUGH
THE END OF THE SHORT TERM PERIOD. THE MODEL CONSENSUS IS FOR ONE
OF THESE TO WORK ACROSS THE LOWER OH VALLEY REGION FROM LATE
TONIGHT INTO SATURDAY. WITH THE SOUTH TO SOUTHWEST FLOW CONTINUING
THROUGH THE COLUMN...MOISTURE WILL INCREASE FURTHER AND PW IS
PROGGED TO REACH THE 1.4 TO 1.6 OR 1.7 INCH RANGE ON SATURDAY.
SOME SPRINKLES OR LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH THE
REMAINDER OF THE OVERNIGHT THROUGH AROUND SUNRISE. ONCE THE
SHORTWAVE MOVES PAST THE AREA TODAY AND THE WARM FRONT LIFTS NORTH
TOWARD THE GREAT LAKES REGION...THERE WILL NOT BE ANY SUBSTANTIAL
TRIGGERS TODAY WITH 500MB HEIGHTS TRENDING UP THROUGH THE DAY.
DIFFERENTIAL HEATING ACROSS THE CUMBERLAND PLATEAU AND THE HIGHER
TERRAIN NEAR THE VA BORDER MAY HELP TO TRIGGER ANY INITIAL
DEVELOPMENT. THE AIRMASS IS EXPECTED TO BE RATHER MOIST AND
SOMEWHAT UNSTABLE BY AFTERNOON WHEN COUPLED WITH DAYTIME HEATING.
THE NAM GUIDANCE IS LIKELY TOO AGGRESSIVE WITH LOW LEVEL MOISTURE
AND CAPE FOR THIS AFTERNOON...BUT THE LESS AGGRESSIVE GFS HAS
CAPE OF AT LEAST 500 TO 1000 J/KG AND LI OF -2 TO -3C OR SO.
ISOLATED TO SCATTERED COVERAGE OF CONVECTION SEEMS PROBABLE...WITH
OUTFLOWS FROM INITIAL CONVECTION POSSIBLY BEING THE TRIGGER FOR
ADDITIONAL CONVECTION IN OTHER LOCATIONS.
A RELATIVE LULL IN COVERAGE OF CONVECTION IS ANTICIPATED FROM MID
TO LATE EVENING IN THE OVERNIGHT HOURS. HOWEVER...ONCE THE RIDGE
AXIS SHIFTS TO THE EAST AND AS A SHORTWAVE APPROACHES FROM THE
SOUTHWEST...ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE LATE
TONIGHT AND CONTINUING INTO SATURDAY. MODELS HAVE CAPE OF ABOUT
1000 TO 1500 J/KG OF SBCAPE ON SATURDAY WITH THIS GENERALLY BEING
OF THE TALL SKINNY CAPE VARIETY. WITH THE SHORTWAVE PASSING
THROUGH THE AREA AND DEWPOINTS EXPECTED TO BE SOLIDLY AT 60F OR
HIGHER...COVERAGE OF CONVECTION SHOULD BE MORE SUBSTANTIAL THAN ON
FRIDAY. THE PW WILL ALSO BE QUITE HIGH FOR MID MAY...AND WARM
CLOUD DEPTHS MAY ALSO APPROACH 10KFT OR MORE. WHAT CONVECTION THAT
DOES DEVELOP ON SATURDAY MAY BE RATHER EFFICIENT RAIN PRODUCERS
WITH QUITE SUBSTANTIAL RAIN RATES. THE STORM MOTIONS ARE PROGGED
TO BE NEARLY 20KTS...SO A LOCATION MAY NEED TO RECEIVE MULTIPLE
STORMS BEFORE HYDRO PROBLEMS MIGHT BEGIN. THE LAST FEW DAYS HAVE
BEEN DRY SO INITIAL STORMS MAY SERVE TO PRIME A LOCATION. ANY
LOCATIONS THAT RECEIVE MULTIPLE STORMS WOULD HAVE THE THREAT FOR
AT LEAST SOME MINOR FLOODING ISSUES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 401 AM EDT FRI MAY 15 2015
WE WILL BEGIN THE LONG TERM PERIOD WITH WARM AND MOIST ENVIRONMENT
AHEAD OF UPPER LEVEL LOW AND FRONT ACROSS THE PLAINS. GENERALLY
WEAK WAVES TRAVELING ALONG THE EDGE OF UPPER LEVEL RIDGE AND
AFTERNOON HEATING WILL HELP TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ONCE CONVECTIVE
TEMPS ARE REACHED. FORECAST SOUNDINGS AND TIME HEIGHT ANALYSIS
INDICATE MOIST COLUMN WITH PWATS IN THE AROUND 1.7 INCHES OR
HIGHER AT TIMES...SO ANY STORMS THAT FIRE HAVE THE POTENTIAL TO
PRODUCE HEAVY RAINFALL RATES SUNDAY INTO MONDAY. THE UPPER LEVEL
LOW ACROSS THE PLAINS WILL MOVE INTO THE GREAT LAKES AND BEGINS TO
FLATTEN OUT THE RIDGING IN PLACE AS WE MOVE INTO MONDAY. SURFACE
FRONT WILL ALSO APPROACH THE REGION MONDAY AND THIS COUPLED WITH
HEIGHT FALLS WILL BRING LIKELY POPS INTO THE REGION AHEAD OF
SURFACE BOUNDARY. KEEP THUNDER IN THE EVENING MONDAY BEFORE
TAPERING OFF INTO RAIN SHOWERS OVERNIGHT INTO TUESDAY MORNING.
RIGHT NOW IT LOOKS LIKE FRONT WILL COME THOUGH SOMETIME TUESDAY
MORNING OR EARLY AFTERNOON...WITH SLIGHTLY DIFFERING TIMING WITH
LONG RANGE MODELS. EITHER WAY THIS WILL USHER IN DRYER AND COOLER
AIR...AS SURFACE HIGH PRESSURE AND NORTHERLY FLOW BUILD INTO THE
REGION BY MID WEEK. WEDNESDAY WILL FEATURE DRY AND COOLER
CONDITIONS...WITH TEMPS TOPING OUT IN THE LOWER 70S. THIS WILL BE
SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. SLIGHT RETURN OF
MOISTURE BY LATE WEEK...BUT RIGHT NOW KEEP IN MOSTLY DRY THROUGH
THE REMAINDER OF THE LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 720 AM EDT FRI MAY 15 2015
VFR CONDITIONS ARE EXPECTED TO PREVAIL ON AVERAGE THROUGH THE
PERIOD. THE FLOW ALOFT WILL CONTINUE TO BE SWRLY...ALLOWING FOR AN
A CONTINUED INCREASE IN MOISTURE FROM TOP DOWN. A FEW SPRINKLES
AND A STRAY SHRA OR TSRA WILL MOVE ACROSS NORTHERN PARTS OF THE
AREA THROUGH AROUND 15Z AND COULD AFFECT MAINLY SYM. CU SHOULD
DEVELOP FROM 15Z ON...WITH ISOLATED TO SCATTERED SHRA AND TSRA.
CONFIDENCE IN THE EXACT LOCATION AND TIMING OF THIS REMAINS
LOW...BUT WE HAVE OPTED TO JUST USE VCTS FROM 17Z THROUGH 23Z. ANY
DIRECT HIT FROM SHRA OR TSRA COULD BRING A BRIEF PERIOD OF IFR OR
LOWER VIS AND OR CIGS. THERE SHOULD BE A LULL IN CONVECTION
CHANCES BETWEEN 23Z AND 6Z...BUT AS ANOTHER DISTURBANCE
NEARS...ISOLATED TO SCATTERED SHRA AND TSRA WILL BE POSSIBLE AT
THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
927 AM EDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 926 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON LATEST RADAR AND
OBSERVATIONAL TRENDS. CURRENTLY A LINE OF SHOWERS WITH A FEW
THUNDERSTORMS IS MOVING ACROSS THE NW PART OF THE FORECAST AREA.
HAVE TIMED THIS ACROSS THE FORECAST AREA BASED ON CURRENT MOVEMENT
AND EXPECTED DIMINISHING TREND. HRRR SEEMS TO BE HANDING THIS
PRETTY GOOD...AND ONCE THIS MOVES OUT EXPECT A LULL BEFORE
ISOLATED CONVECTION BEGINS TO POP UP THIS AFTERNOON.
UPDATE ISSUED AT 715 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
RADAR TRENDS. ISOLATED SHOWERS AND EVEN A STRAY THUNDERSTORM AS
WELL AS SOME SPRINKLES WILL WORK ACROSS THE NORTHERN HALF TO TWO
OF THE AREA AS A SHORTWAVE WORKS THROUGH THE REGION. ADDITIONAL
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 15 2015
EARLY THIS MORNING...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS
CENTERED JUST EAST OF THE FLORIDA PENINSULA WITH SHORTWAVE
RIDGING NORTH ALONG THE EASTERN SEABOARD AND ANOTHER SHORTWAVE
RIDGE NORTHWEST INTO PARTS OF THE CENTRAL AND NORTHERN PLAINS. IN
BETWEEN...A SHORTWAVE TROUGH WAS WORKING TOWARD THE GREAT LAKES
AND ACROSS PARTS OF THE OH VALLEY AS IT MOVES AROUND THIS RIDGE.
FURTHER TO THE WEST...A TROUGH WAS MOVING INTO THE WESTERN CONUS.
THE SHORTWAVE WORKING ACROSS THE REGION AND THE ASSOCIATED SFC
SYSTEM WARM FRONT THAT IS GRADUALLY LIFTING NORTH ACROSS THE AREA
HAVE BROUGHT INCREASING MOISTURE THROUGH THE ENTIRE COLUMN TO THE
REGION. THIS HAS MAINLY BEEN REALIZED IN MID AND HIGH CLOUDS SO
FAR AND WARMER TEMPERATURES ATTM COMPARED TO 24 AND 48 HOURS AGO
DUE TO HIGHER SFC DEWPOINTS AND THE CLOUD COVER.
THE SHORTWAVE WILL MOVE INTO THE EASTERN GREAT LAKES AND MOVE
EAST OF THE AREA THIS MORNING...WITH SHORTWAVE RIDGING PROGGED TO
WORK ACROSS THE AREA FROM MIDDAY INTO THE EARLY EVENING. BEHIND
THE WARM FRONT...PW IS PROGGED TO BE IN THE 1.1 TO 1.3 INCH RANGE
OR SO. THE RIDGE AXIS IS EXPECTED TO MOVE EAST OF THE AREA
TONIGHT WITH THE REGION IN SOUTH TO SOUTHWEST FLOW ALOFT THROUGH
THE END OF THE PERIOD. WEAK SHORTWAVES WILL LIKELY MOVE ACROSS THE
AREA IN THIS FLOW AT TIMES FROM THIS EVENING OR TONIGHT THROUGH
THE END OF THE SHORT TERM PERIOD. THE MODEL CONSENSUS IS FOR ONE
OF THESE TO WORK ACROSS THE LOWER OH VALLEY REGION FROM LATE
TONIGHT INTO SATURDAY. WITH THE SOUTH TO SOUTHWEST FLOW CONTINUING
THROUGH THE COLUMN...MOISTURE WILL INCREASE FURTHER AND PW IS
PROGGED TO REACH THE 1.4 TO 1.6 OR 1.7 INCH RANGE ON SATURDAY.
SOME SPRINKLES OR LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH THE
REMAINDER OF THE OVERNIGHT THROUGH AROUND SUNRISE. ONCE THE
SHORTWAVE MOVES PAST THE AREA TODAY AND THE WARM FRONT LIFTS NORTH
TOWARD THE GREAT LAKES REGION...THERE WILL NOT BE ANY SUBSTANTIAL
TRIGGERS TODAY WITH 500MB HEIGHTS TRENDING UP THROUGH THE DAY.
DIFFERENTIAL HEATING ACROSS THE CUMBERLAND PLATEAU AND THE HIGHER
TERRAIN NEAR THE VA BORDER MAY HELP TO TRIGGER ANY INITIAL
DEVELOPMENT. THE AIRMASS IS EXPECTED TO BE RATHER MOIST AND
SOMEWHAT UNSTABLE BY AFTERNOON WHEN COUPLED WITH DAYTIME HEATING.
THE NAM GUIDANCE IS LIKELY TOO AGGRESSIVE WITH LOW LEVEL MOISTURE
AND CAPE FOR THIS AFTERNOON...BUT THE LESS AGGRESSIVE GFS HAS
CAPE OF AT LEAST 500 TO 1000 J/KG AND LI OF -2 TO -3C OR SO.
ISOLATED TO SCATTERED COVERAGE OF CONVECTION SEEMS PROBABLE...WITH
OUTFLOWS FROM INITIAL CONVECTION POSSIBLY BEING THE TRIGGER FOR
ADDITIONAL CONVECTION IN OTHER LOCATIONS.
A RELATIVE LULL IN COVERAGE OF CONVECTION IS ANTICIPATED FROM MID
TO LATE EVENING IN THE OVERNIGHT HOURS. HOWEVER...ONCE THE RIDGE
AXIS SHIFTS TO THE EAST AND AS A SHORTWAVE APPROACHES FROM THE
SOUTHWEST...ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE LATE
TONIGHT AND CONTINUING INTO SATURDAY. MODELS HAVE CAPE OF ABOUT
1000 TO 1500 J/KG OF SBCAPE ON SATURDAY WITH THIS GENERALLY BEING
OF THE TALL SKINNY CAPE VARIETY. WITH THE SHORTWAVE PASSING
THROUGH THE AREA AND DEWPOINTS EXPECTED TO BE SOLIDLY AT 60F OR
HIGHER...COVERAGE OF CONVECTION SHOULD BE MORE SUBSTANTIAL THAN ON
FRIDAY. THE PW WILL ALSO BE QUITE HIGH FOR MID MAY...AND WARM
CLOUD DEPTHS MAY ALSO APPROACH 10KFT OR MORE. WHAT CONVECTION THAT
DOES DEVELOP ON SATURDAY MAY BE RATHER EFFICIENT RAIN PRODUCERS
WITH QUITE SUBSTANTIAL RAIN RATES. THE STORM MOTIONS ARE PROGGED
TO BE NEARLY 20KTS...SO A LOCATION MAY NEED TO RECEIVE MULTIPLE
STORMS BEFORE HYDRO PROBLEMS MIGHT BEGIN. THE LAST FEW DAYS HAVE
BEEN DRY SO INITIAL STORMS MAY SERVE TO PRIME A LOCATION. ANY
LOCATIONS THAT RECEIVE MULTIPLE STORMS WOULD HAVE THE THREAT FOR
AT LEAST SOME MINOR FLOODING ISSUES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 401 AM EDT FRI MAY 15 2015
WE WILL BEGIN THE LONG TERM PERIOD WITH WARM AND MOIST ENVIRONMENT
AHEAD OF UPPER LEVEL LOW AND FRONT ACROSS THE PLAINS. GENERALLY
WEAK WAVES TRAVELING ALONG THE EDGE OF UPPER LEVEL RIDGE AND
AFTERNOON HEATING WILL HELP TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ONCE CONVECTIVE
TEMPS ARE REACHED. FORECAST SOUNDINGS AND TIME HEIGHT ANALYSIS
INDICATE MOIST COLUMN WITH PWATS IN THE AROUND 1.7 INCHES OR
HIGHER AT TIMES...SO ANY STORMS THAT FIRE HAVE THE POTENTIAL TO
PRODUCE HEAVY RAINFALL RATES SUNDAY INTO MONDAY. THE UPPER LEVEL
LOW ACROSS THE PLAINS WILL MOVE INTO THE GREAT LAKES AND BEGINS TO
FLATTEN OUT THE RIDGING IN PLACE AS WE MOVE INTO MONDAY. SURFACE
FRONT WILL ALSO APPROACH THE REGION MONDAY AND THIS COUPLED WITH
HEIGHT FALLS WILL BRING LIKELY POPS INTO THE REGION AHEAD OF
SURFACE BOUNDARY. KEEP THUNDER IN THE EVENING MONDAY BEFORE
TAPERING OFF INTO RAIN SHOWERS OVERNIGHT INTO TUESDAY MORNING.
RIGHT NOW IT LOOKS LIKE FRONT WILL COME THOUGH SOMETIME TUESDAY
MORNING OR EARLY AFTERNOON...WITH SLIGHTLY DIFFERING TIMING WITH
LONG RANGE MODELS. EITHER WAY THIS WILL USHER IN DRYER AND COOLER
AIR...AS SURFACE HIGH PRESSURE AND NORTHERLY FLOW BUILD INTO THE
REGION BY MID WEEK. WEDNESDAY WILL FEATURE DRY AND COOLER
CONDITIONS...WITH TEMPS TOPING OUT IN THE LOWER 70S. THIS WILL BE
SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. SLIGHT RETURN OF
MOISTURE BY LATE WEEK...BUT RIGHT NOW KEEP IN MOSTLY DRY THROUGH
THE REMAINDER OF THE LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 720 AM EDT FRI MAY 15 2015
VFR CONDITIONS ARE EXPECTED TO PREVAIL ON AVERAGE THROUGH THE
PERIOD. THE FLOW ALOFT WILL CONTINUE TO BE SWRLY...ALLOWING FOR AN
A CONTINUED INCREASE IN MOISTURE FROM TOP DOWN. A FEW SPRINKLES
AND A STRAY SHRA OR TSRA WILL MOVE ACROSS NORTHERN PARTS OF THE
AREA THROUGH AROUND 15Z AND COULD AFFECT MAINLY SYM. CU SHOULD
DEVELOP FROM 15Z ON...WITH ISOLATED TO SCATTERED SHRA AND TSRA.
CONFIDENCE IN THE EXACT LOCATION AND TIMING OF THIS REMAINS
LOW...BUT WE HAVE OPTED TO JUST USE VCTS FROM 17Z THROUGH 23Z. ANY
DIRECT HIT FROM SHRA OR TSRA COULD BRING A BRIEF PERIOD OF IFR OR
LOWER VIS AND OR CIGS. THERE SHOULD BE A LULL IN CONVECTION
CHANCES BETWEEN 23Z AND 6Z...BUT AS ANOTHER DISTURBANCE
NEARS...ISOLATED TO SCATTERED SHRA AND TSRA WILL BE POSSIBLE AT
THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1037 AM CDT FRI MAY 15 2015
.UPDATE...
MAIN CHANGES TO FORECAST FOR TODAY ARE TO INCREASE POPS.
&&
.SHORT TERM...
MORNING OBSERVATIONAL DATA DEPICT AN ANOMALOUSLY MOIST AIRMASS
ACROSS REGION...PARTICULARLY IN LOWER LEVELS WITH LOWER 70S DEWPOINTS
AND 330-335 850 MB THETA-E VALUES. CONVECTION IS ALREADY BEGINNING TO
DEVELOP FROM S MS INTO S LA WITH DAYTIME HEATING AND APPROACH OF WEAK
UPPER WAVE FROM TX. ALL SHORT RANGE GUIDANCE SUGGESTS THAT CONVECTION
WILL CONTINUE TO INCREASE IN COVERAGE THROUGH THE DAY AND PROPAGATE
NORTH DUE TO 15-20 KT LOW/MID LEVEL S/SW FLOW. THIS EXPECTED SCENARIO
AND HRRR QPF SUGGESTS WIDESPREAD COVERAGE OF SHRA/TSRA TODAY AND
HAVE INCREASED POPS TO SHOW LIKELY CATEGORY ALL AREAS. AS DISCUSSED
BY PREVIOUS SHIFT...PRESENCE OF THIS FLOW...INCLUDING 20-30 KT 500 MB
WINDS...ALONG WITH SBCAPE VALUES OF 2000-3000 J/KG SUGGESTS THAT
SOMEWHAT ORGANIZED CONVECTION WITH STRONG WIND GUSTS IS POSSIBLE.
HOWEVER GIVEN EARLY START TO CONVECTION AND WEAK DCAPE VALUES WILL
HOLD OFF ON MENTIONING ANY STRONG/SEVERE ACTIVITY IN HWO OR GRAPHICS.
TEMPERATURE FORECAST LOOKS GOOD...HRRR SEEMS OVERAGGRESSIVE SHOWING
TEMPS REACHING LOWER 90S MOST AREAS CONSIDERING LOW LEVEL MOISTURE
AND EXPECTED CONVECTION. STUCK WITH ONGOING GRIDS. /AEG/
&&
.AVIATION...WHILE VFR CONDITIONS WILL EXIST FOR THE MOST PART THIS
AFTERNOON...SCATTERED TO NUMEROUS TSRA WILL EASILY ALLOW CIGS/VSBYS
TO BRIEFLY DROP TO MVFR. THESE CONDITIONS WILL LIKELY PERSIST UNTIL
02Z... DIMINISHING THEREAFTER. MVFR CIGS/VSBY WILL DEVELOP AFTER 06Z
WITH IFR CEILINGS DEVELOPING AT HBG./26/
&&
.PREV DISCUSSION... /ISSUED 432 AM CDT FRI MAY 15 2015/
DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...A SUBTROPICAL RIDGE WILL CONTINUE TO
BE CENTERED OVER THE SOUTH ATLANTIC STATES AS WE GO INTO THE WEEKEND.
TO THE WEST OF THE RIDGE OVER THE ARKLAMISS...WARM SOUTHERLY FLOW IN
THE LOW LEVELS JUXTAPOSED BY DISTURBED SOUTHWEST FLOW ALOFT WILL
SUPPORT A WARM/MOIST (PRECIPITABLE WATER > 1.75 INCHES) AND UNSTABLE
AIRMASS WITH SCATTERED MAINLY AFTERNOON THUNDERSTORM COVERAGE. IT IS
DIFFICULT TO FIND SPECIFIC FOCUSING MECHANISMS THAT SUPPORT GOING
WITH HIGHER THAN CHANCE POPS...BUT A SUBTLE UPPER LEVEL SHORTWAVE
TROUGH CURRENTLY APPROACHING THE ARKLATEX REGION MAY ENHANCE
ACTIVITY LATER TODAY OVER THE FORECAST AREA. AND THEN FOR
SATURDAY...SLIGHTLY INCREASED SOUTHERLY FLOW AND LOW LEVEL
CONVERGENCE MAY ALSO RESULT IN GREATER COVERAGE WITH SOMEWHAT
FAVORABLE UPPER LEVEL DIVERGENCE REMAINING IN PLACE.
WHILE DEEP LAYER SHEAR IS NOT FORECAST TO BE FAVORABLE FOR ORGANIZED
SEVERE WEATHER...THERE SHOULD BE ENOUGH FLOW FOR MULTICELL LINE
SEGMENTS WITH LOW LEVEL FLOW SUPPORTING A FEW STRONG WIND
GUSTS...ESPECIALLY IN AREAS WHERE STORMS MOVE IN DURING TIME OF PEAK
HEATING AND MAXIMUM INSTABILITY. MOREOVER...THIS FLOW WOULD HELP TO
INCREASE STORM MOTIONS AND OVERALL RAINFALL COVERAGE. /EC/
SUNDAY THROUGH THURSDAY NIGHT...THE WARM AND HUMID CONDITIONS WILL
CONTINUE ON SUNDAY WITH ANOTHER ROUND OF DIURNAL CONVECTION AS THE
AREA CONTINUES TO BE SANDWICHED IN BETWEEN MID LEVEL RIDGING TO THE
EAST AND TROUGHING TO THE WEST. SUNDAY NIGHT THE RIDGE WILL BREAK
DOWN AS MID LEVEL TROUGHING DEEPENS OVER THE EASTERN PLAINS AND
DRIVES A COLD FRONT SOUTH ACROSS THE AREA ON MONDAY. EXPECT ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS ON MONDAY AS THE COLD FRONT MOVES
INTO THE AREA. THE ECMWF IS A LITTLE SLOWER WITH THE BOUNDARY MOVING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...BUT EITHER WAY EXPECT A
CONTINUATION OF THE WET PATTERN ON TUESDAY. BOTH THE GFS/ECMWF BUILD
SURFACE HIGH PRESSURE RIDGING AND A LITTLE DRIER AIR IN ON WEDNESDAY
AND THEN BRING ANOTHER COLD FRONT ACROSS THE AREA ON THURSDAY WITH
MORE SHOWERS AND THUNDERSTORMS. IT MOST DEFINITELY LOOKS LIKE WE WILL
HAVE FORGOTTEN ABOUT THE DRY WEATHER AS OF LATE BY THE END OF THE
LONG TERM./15/
AVIATION...SCATTERED AREAS OF IFR STRATUS SHOULD DEVELOP EARLY THIS
MORNING...ESPECIALLY IN THE HBG AREA...BUT FLOW THUS FAR HAS BEEN
STRONG ENOUGH TO SLOW DOWN FOG DEVELOPMENT. SCATTERED DIURNAL SHRA/TSRA
WILL POTENTIALLY AFFECT ALL SITES THIS AFTN INTO EARLY EVNG IN THE
WARM/MOIST AND UNSTABLE AIRMASS. MOST RECENT SREF GUIDANCE SUGGESTS
BETTER POTENTIAL FOR LOW CIGS TO DEVELOP EARLY SATURDAY MORNING WITH
INCREASING SOUTHERLY FLOW. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 85 69 83 70 / 63 42 56 38
MERIDIAN 86 69 83 69 / 63 41 61 40
VICKSBURG 86 71 84 71 / 59 44 53 33
HATTIESBURG 86 70 83 70 / 70 30 58 40
NATCHEZ 85 70 84 71 / 62 40 52 36
GREENVILLE 87 71 83 71 / 65 49 59 38
GREENWOOD 86 70 82 70 / 64 49 58 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG/26
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
641 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CDT FRI MAY 15 2015
TODAY AND TONIGHT... A WEAK COLD FRONT HAS DROPPED SOUTH TO JUST
NORTH OF INTERSTATE 80 PER SFC OBS AND RTMA ANALYSIS. EAST WINDS ARE
UNDERWAY IN THE PLATTE VALLEY. STRATUS NORTH OF THE FRONT ACROSS NRN
NEB COULD SPREAD SOUTH TO NEAR THEDFORD AND PERHAPS AS FAR SOUTH AS
BROKEN BOW BY MORNING. THE THUNDERSTORMS UNDERWAY ACROSS SWRN NEB
THIS MORNING SHOULD MOVE UP AND OVER THE FRONT PRODUCING RAIN COOLED
AIR WHICH WOULD KEEP THE FRONT IN OR NEAR THE PLATTE VALLEY UNTIL
AFTERNOON. THIS AFTERNOON...FRONT COULD BEGIN TO MOVE NORTH SLOWLY.
THE MODEL CONSENSUS SHOWS THE FRONT LIFTING RAPIDLY NORTH TONIGHT.
THE BEST GUESS ON THE SEVERE WEATHER IS A BIT OPTIMISTIC. STRONG
WINDS ALOFT...40 TO 50 KT AT 500 MB AND 60 KT AT 300 MB SHOULD MOVE
INTO SWRN NEB AROUND 18Z AND FIRE CONVECTION ON A WARM FRONT DRAPED
ACROSS THE SRN SANDHILLS BY 21Z...PERHAPS ALIGNED E-SE TOWARD
LEXINGTON. THE RAP SHOWS LARGE SCALE LIFT AT THE SAME TIME EMANATING
FROM A LONG WAVE TROF OVER THE SWRN U.S.
TORNADO PARAMETERS LOOK REASONABLY GOOD WITH NICELY CURVED
HODOGRAPHS NEAR THE FRONT FOR SEVERAL HOURS DURING THE AFTN. THIS
PRODUCES 0-3KM HELICITY OVER 400 M2/S2 AND WHEN COMBINED WITH THE
INSTABILITY THE ENERGY HELICITY INDEX IS OVER 4 ALONG THE FRONT.
THUS A TORNADO OR TWO COULD FORM. WINDS ALOFT ARE A BIT LINEAR AND
CONRAD CONTINUES TO SUGGEST SPLITTING DOMINANT RIGHT MOVING
SUPERCELLS.
NOTE THE RAP...THE FAVORED MODEL...MOVES THE FRONT VERY LITTLE TODAY
WHICH COULD ALLOW FOR SEVERE STORMS TO RIDE UP AND OVER THE FRONT
AND BECOME MORE OF A HAIL THREAT.
SPC SUGGESTED STORM ACTIVITY WOULD WEAKEN THIS EVENING AND IT IS
POSSIBLE THE LARGE SCALE LIFT AND UPPER LEVEL SUPPORT COULD DO THE
SAME CARRYING THE BULK OF THE STORM ACTION INTO NRN NEB BY 00Z AS
SUGGESTED BY THE MODEL CONSENSUS.
THE FORECAST USES A BLEND OF THE RAP...NAM...GEMREG...ARW AND NMM.
THE OTHER MODELS WERE TOO COARSE RESOLUTION TO CAPTURE THE SPIRIT OF
THE EVENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CDT FRI MAY 15 2015
DETERMINISTIC MODELS AND ENSEMBLE MEANS CONTINUE TO ADVERTISE A
PERSISTENT UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT
WEEK. BLOCKY SETUP ALONG THE WEST COAST INTO THE CENTRAL ROCKIES
WITH A HIGH AMPLITUDE RIDGE OVER WESTERN CANADA OVER THE TOP OF A
BROAD TROUGH EXTENDING SOUTHWARD TOWARD THE BAJA OF CALIFORNIA.
RIDGE TO THE EAST WILL BEGIN TO FLATTEN INTO EARLY NEXT WEEK AS A
LOW BUILDS INTO SOUTHEAST CANADA. THE MEAN UPPER LEVEL FLOW OVER THE
CENTRAL PLAINS REMAINS OUT OF THE SOUTHWEST THROUGH THE LONG RANGE
PERIOD AND IN THE CROSSHAIRS OF SEVERAL SHORTWAVE PERTURBATIONS
ASSOCIATED WITH THE WESTERN CONUS TROUGH.
ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE AGAIN ON SATURDAY AS
STRONG PV MAX AND UPPER LEVEL JET STREAK EJECT NORTHEAST OUT OF THE
FOUR CORNERS REGION. LEE SIDE LOW AND ASSOCIATED PACIFIC FRONT MAKE
LITTLE EASTWARD PROGRESSION TOWARD THE EASTERN NEBRASKA PANHANDLE BY
THE BEGINNING OF THE PERIOD. SCATTERED ELEVATED STORMS LEFTOVER FROM
FRIDAY NIGHT SHOULD BE PUSHING NORTH AND EAST OF THE CWA DURING THE
MORNING HOURS...AIDED BY A VEERING LLJ. CONVECTIVE INITIATION IS
LIKELY ONCE AGAIN BY MID AFTERNOON IN AN INCREASINGLY UNSTABLE WARM
SECTOR EAST OF THE PACIFIC FRONT. MODELS ARE STRUGGLING WITH THEIR
HANDLING OF WARM SECTOR RECOVERY...AND ANY CLOUD COVER WILL HAVE A
SIGNIFICANT IMPACT ON THE DEGREE OF DESTABILIZATION. HOWEVER SEVERE
STORMS WILL STILL BE POSSIBLE GIVEN THE STRONG FORCING FOR ASCENT
AND FAVORABLE DEEP LAYER SHEAR. WIND PROFILES CONTINUE TO LOOK
FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...FAVORING
UPSCALE GROWTH AS THE THUNDERSTORM ACTIVITY EVOLVES THROUGH THE
AFTERNOON AND EVENING. LARGE HAIL...DAMAGING WINDS WILL BE THE
PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL ALSO NEED TO BE CLOSELY
WATCHED AS SOME AREAS MAY EXPERIENCE SEVERAL ROUNDS/TRAINING
THUNDERSTORMS.
SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY ACROSS THE NORTHERN
TIER OF THE CWA. LOW LEVEL MOISTURE WRAPS AROUND THE BACKSIDE OF THE
SFC LOW NOW OVER THE DAKOTAS AND BACK INTO NEBRASKA...UNDERNEATH
ANOMALOUSLY COLD AIR ALOFT ASSOCIATED WITH THE PASSING OF THE
UPPER LEVEL LOW. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS
EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS.
THE MIDDLE OF THE WEEK LOOKS COOL AND WET AS ANOTHER UPPER LEVEL
SHORTWAVE TROUGH PIVOTS NORTHEAST THROUGH THE EASTERN ROCKIES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 640 AM CDT FRI MAY 15 2015
THE THUNDERSTORM COMPLEX UNDERWAY IS EXPECTED TO MOVE NORTH THIS
MORNING AND EXIT NORTHERN NEB AROUND 18Z. AT ABOUT THAT SAME
TIME...A STRONG UPPER LEVEL DISTURBANCE WILL BEGIN IMPOSING ON
SWRN NEB AND THE SRN PANHANDLE PRODUCING ANOTHER ROUND STRONG TO
SEVERE STORMS WHICH WOULD ALSO LIFT NORTH DURING THE AFTN AND
EARLY EVENING.
THE RAP/NAM/GFS SUGGESTS THE IFR/LIFR ACROSS NCNTL NEB WILL
IMPROVE TO MVFR LATER THIS MORNING AND PERHAPS VFR THIS AFTN. VFR
IS EXPECTED AFTER 06Z TONIGHT EXCEPT THE NAM IS PRODUCING TSTMS
NEAR AND SOUTH OF KLBF 06Z-12Z SATURDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
954 AM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 954 AM CDT FRI MAY 15 2015
HIGH PRESSURE NOSING INTO NORTHEAST NORTH DAKOTA ALONG WITH A
DRIER AIRMASS (CLEAR SKY). THE MAIN CHALLENGE FOR TODAY WILL BE
THE DEGREE OF CLEARING AND THIS AFFECT ON MAX TEMPS. HIGH PRESSURE
CONTINUE TO BUILD INTO THE REGION TODAY...ALTHOUGH WITH HIGHER
BASED CLOUDS ADVECTING INTO THE REGION FROM THE SOUTH...AREAS
ACROSS SOUTHEAST ND AND WC MN MAY NEVER TOTALLY BECOME CLEAR. WITH
THE CURRENT CLEAR SKY ACROSS THE NE ND DID RAISE MAX TEMPS A
COUPLE DEGREES HERE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
MODELS IN GOOD AGREEMENT FOR TODAY WITH SFC HIGH PRESSURE TO THE
NW BRINGING A TIGHTENING OF THE SFC PRESSURE GRADIENT. THIS IS
ALLOWING DRIER AIR AND CLEARING SKIES TO WORK INTO THE DEVILS LAKE
BASIN. AHEAD OF THE THIS FEATURE IS A SATURATED AIRMASS WITH
AREAS OF FOG AND SOME PATCHY DRIZZLE OCCURRING AS DEWPOINTS ARE IN
THE UPR 40S. WILL KEEP THE DRIZZLE FOG MENTION THRU 9AM.
AS THE MORNING TURNS INTO MID DAY UNCERTAINTY EXISTS IN THE
SOUTHWARD EXTENT OF THE CLEARING AND CLOUD COVER. RECENT THE RAP
AND HRRR MESOSCALE MODEL RUNS BRING THE CLEARING TO GFK BUT NOT
AS FAR SOUTH AS FARGO.
TONIGHT ATTENTION TURNS TO STRONG MOISTURE AND WARM AIR ADVECTION
ESCORTED NORTHWARD BY 30 TO 40 KT 850MB SOUTHERLY JET WHICH WILL
CONTINUE THROUGH THE DAY SATURDAY. AMOUNT OF CLOUD COVER WILL
DETERMINE SFC TEMPS AND AMOUNT OF INSTABILITY THAT DEVELOPS AHEAD
OF A DEVELOPING SFC LOW ACROSS THE WESTERN DAKOTAS. MODEL TRENDS
ARE SLOWER WITH THE SYSTEM BRINGING THE SFC LOW TO THE TRI STATE
CORNER ABOUT 12 LATER THAN PREVIOUSLY FORECAST. THAT SAID THERE
REMAINS A SLIGHT RISK FOR SEVERE STORMS ACROSS MUCH OF THE AREA ON
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
SATURDAY NIGHT INTO SUNDAY NIGHT...THE STACKED SYSTEM WRAPS MOISTURE
BACK ACROSS MUCH OF THE CWFA. WITH CATEGORICAL POPS FOR THE ENTIRE
FA SUNDAY WITH DEFORMATION BAND OF RAIN. NORTH WINDS WILL
INCREASE INTO THE 20 TO 30 KT RANGE SUNDAY ACROSS THE WEST AND
SLOWLY WORK TO THE EAST DURING THE DAY. AHEAD OF THE SFC LOW AND
WIND SHIFT THERE REMAINS A CHANCE FOR THUNDER WITH NEGATIVE
SHOWALTERS THROUGH EARLY AFTERNOON. AS THE SYSTEM SLOWING PUSHES
EAST 925MB TEMPS ACROSS THE DVL BSN AND N RRV DO DROP WELL BELOW
0C AND MODELS CONTINUE TO HINT AND THE POSSIBILITY OF SOME SNOW
FLAKES MIXED IN WITH THE BACKEND OF THE PCPN SHIELD. TOTAL
RAINFALL AMOUNTS ARE EXPECTED TO BE A WIDESPREAD 1 TO 2 INCHES
THROUGH SUNDAY NIGHT.
MONDAY TO THURSDAY...LONG WAVE RIDGE OVER THE WESTERN CANADA MOVES
LITTLE THROUGH THE PERIOD. LONG WAVE TROUGH OVER NORTHEAST CANADA
SHIFTS EAST INTO EASTERN CANADA. REX BLOCK WAS OVER WESTERN NORTH
AMERICA. COLD FRONT FORECAST TO MOVE THROUGH EARLY IN THE PERIOD.
A SURFACE RIDGE MOVES INTO THE AREA TUE NIGHT. GFS WAS A LITTLE
FASTER THAN THE ECMWF. WILL PREFER THE ECMWF.
HIGH TEMPS WERE LOWERED FOR MON AND TUE BY ONE TO FOURS DEGREES.
LITTLE CHANGE ON WED AND THU WAS INCREASED ONE OR TWO DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 638 AM CDT FRI MAY 15 2015
IFR CIGS AS MOST SITES WITH CIGS EXPECTED TO SLOWLY RISE TO MVFR
TODAY AND INTO VFR THIS AFTN. SOME FG AND BR THIS MORNING SHOULD
MIX OUT IN THE NEXT FEW HOURS. RAIN OR THUNDER POSSIBLE OVERNIGHT
THOUGH TIMING AND LOCATION REMAIN UNCERTAIN ENOUGH TO LEAVE OUT OF
TAFS FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...JK
LONG TERM...HOPPES/JK
AVIATION...JK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
746 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A DEVELOPING WARM FRONT OVER THE OHIO VALLEY WILL INITIATE SOME
SHOWERS AND A FEW THUNDERSTORMS TODAY AS IT MOVES NORTHEAST ACROSS
THE AREA. A WARMER AND MORE HUMID AIRMASS WILL BE IN PLACE FOR THE
WEEKEND WHEN HIGH PRESSURE TO OUR EAST RESULTS IN SOUTHERLY FLOW.
A COLD FRONT WILL MOVE ACROSS THE AREA ON MONDAY AND BRING COOLER
TEMPERATURES FOR MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS ASSOCIATED WITH WARM ADVECTION HAVE NOW REACHED INTO
NORTHWEST OHIO. AS AN UPPER LEVEL SHORTWAVE CROSSES THE REGION
EXPECT THESE SHOWERS TO WORK THEIR WAY ACROSS NRN OH AND INTO NW
PA BY MID AFTERNOON. SOME RUMBLES OF THUNDER ARE ALSO POSSIBLE
THIS MORNING...NOT MUCH IN THE WAY OF ELEVATED INSTABILITY.
LATEST HRRR RUNS HAVE A GOOD HANDLE ON THE CURRENT SITUATION AND
HAVE USED THAT AS A GUIDE FOR THIS CURRENT BATCH OF SHOWERS.
ATTEMPTED TO MOVE THE BETTER CHANCES ACROSS THE AREA DURING THE
MORNING AND EARLY AFTERNOON. LATER TODAY NW OHIO WILL BE ABLE TO
RECOVER AND GET SOMEWHAT UNSTABLE. THE UPPER SUPPORT WILL BE
LACKING AND THEREFORE ANY CONVECTION THAT CAN POP UP ALONG A
RECOVERING INSTABILITY AXIS WOULD NOT BE ORGANIZED AND NOT COVER A
LOT OF GROUND. INCREASED PRECIP CHANCES TOWARD TOLEDO BEFORE
EVENING IF ADDITIONAL CONVECTION CAN DEVELOP...AND LINGERED POPS
ELSEWHERE. TEMPERATURES TODAY WILL BE MUCH MILDER....SOLIDLY IN
THE 70S...WITH SPOTS WEST OF CLEVELAND GETTING CLOSE TO 80. EARLY
MORNING UPDATE INCLUDED TWEAKS TO HOURLY TEMPERATURES AND TO
INCREASE PRECIP CHANCE FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
A RATHER WARM AND SOMEWHAT HUMID PERIOD IS EXPECTED WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE SHORT TERM.
THE BIG QUESTION OF WHETHER IT WILL RAIN/THUNDER OVER YOUR HEAD IS
STILL HARD TO ANSWER AND UNFORTUNATELY THE FORECAST STILL REMAINS
FAIRLY GENERIC WITH PRECIP CHANCES THAT FLUCTUATE DIURNALLY. WE
WILL BE IN THE WARM SECTOR AND THERE IS NO LARGE SCALE FORCING TO
INITIATE OR MAINTAIN CONVECTION. OVERALL THE UPPER RIDGE WILL ACT
TO SUPPRESS CONVECTION. AT THE SAME TIME THOUGH MODELS SHOWING AN
INCREASE IN MOISTURE AND QPF. THE QPF IS LIKELY OVERDONE AS HAS
BEEN THE CASE LATELY. IT WILL BE SMALLER SCALE FEATURES THAT WILL
ACT TO INITIATE CONVECTION AND THEREFORE WILL HAVE TO TAKE IT ONE
DAY AT A TIME IN DETERMINING WHO HAS THE BEST CHANCES AND HOW GOOD
OF A CHANCE IT REALLY IS.
IT WILL BE WARM AND MORE HUMID. EXPECT HIGHS OVER THE WEEKEND TO
REACH OR EXCEED 80 AWAY FROM THE LAKE. DEWPOINTS WILL BE NEARING
60 AND NIGHT LOWS WILL BE MILD.
THE COLD FRONT IS EXPECTED TO CROSS MONDAY. HAVE CONTINUED WITH THE
60 PERCENT OR GREATER PRECIP CHANCES WITH THIS SIGNIFICANT
FEATURE...BUT TIMING STILL UNCERTAIN AS IS HOW MUCH ACTIVITY THERE
WILL BE LEADING UP TO IT SUNDAY NIGHT. THE COLD FRONT ITSELF
CROSSES MONDAY EVENING. THERE STILL REMAINS DIFFERENCES ON HOW
MUCH COOL AIR IT BRINGS IN ITS WAKE.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STARTING 12Z TUESDAY A COLD FRONT WILL BE EAST OF THE AREA. HIGH
PRESSURE WILL QUICKLY FILL IN BEHIND THE FRONT...SETTING THE STAGE
FOR STRONG RADIATIONAL COOLING TUESDAY NIGHT. TEMPERATURES WILL FALL
BACK INTO THE LOW 40`S ACROSS THE REGION UNDER A MOSTLY CLEAR SKY.
TUESDAY`S HIGHS WILL STRUGGLE TO GET MUCH ABOVE 60.
BY TUESDAY THE PATTERN BECOMES DE-AMPLIFIED AS AN UPPER LEVEL LOW
SHUFFLES EAST. A BROAD AREA OF HIGH PRESSURE WILL BECOME ESTABLISHED
OVER THE MIDSECTION OF THE COUNTRY AND SPREAD EAST THROUGH THE
REMAINDER OF THE EXTENDED FORECAST. THE WEATHER WILL BE PLEASANT AND
SEASONABLE.
REMOVED SLIGHT CHANCE POPS FROM THE FORECAST ON THURSDAY
AFTERNOON. SHOULD SEE MORE IN THE WAY OF CLOUDS THAN RAIN IN LIGHT
OF ZONAL FLOW ALOFT AND LARGE SURFACE HIGH.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHOWERS ARE NOW MOVING THROUGH OHIO THIS MORNING. THESE SHOWERS
WILL BRIEFLY DROP VISIBILITY TO MVFR. AN ISOLATED RUMBLE OF
THUNDER IS ALSO POSSIBLE WITH THESE SHOWERS. AFTER THE RAIN CLEARS
ERIE BY LATE MORNING FRIDAY...SKIES WILL BECOME MOSTLY OVERCAST
AND THE WIND WILL BEGIN TO PICK UP OUT THE SOUTH. WESTERNMOST
SITES HAVE THE POTENTIAL TO GUST UP TO 25 KNOTS BY THIS
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP
LATER IN THE AFTERNOON AND LAST INTO THE EVENING. OVERNIGHT MVFR
FOG WILL DEVELOP AT MANY TERMINALS AS DEW POINTS CLIMB INTO
THE 60/S AND THE WIND DECREASES TO AROUND 5 KNOTS.
.OUTLOOK...NON VFR AT TIMES IN SCATTERED SHOWERS OR THUNDERSTORMS
THRU MON EVENING.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH ACROSS LAKE ERIE EARLY FRIDAY
AFTERNOON. WAVES WILL GENERALLY BE 3 FEET OF LESS ON THE OPEN WATERS
THROUGH THE WEEKEND WITH SOUTH TO SOUTHWEST FLOW OF 15 KNOTS OR
LESS.
MONDAY NIGHT A COLD FRONT WILL CROSS THE LAKE AND WAVES WILL BUILD
TO 2 TO 4 FEET ON THE OPEN LAKE. BY TUESDAY MORNING THE WIND WILL BE
FROM THE NORTHWEST AT 10 TO 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...MAYERS
AVIATION...MAYERS
MARINE...MAYERS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
627 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A DEVELOPING WARM FRONT OVER THE OHIO VALLEY WILL INITIATE SOME
SHOWERS AND A FEW THUNDERSTORMS TODAY AS IT MOVES NORTHEAST ACROSS
THE AREA. A WARMER AND MORE HUMID AIRMASS WILL BE IN PLACE FOR THE
WEEKEND WHEN HIGH PRESSURE TO OUR EAST RESULTS IN SOUTHERLY FLOW.
A COLD FRONT WILL MOVE ACROSS THE AREA ON MONDAY AND BRING COOLER
TEMPERATURES FOR MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS ASSOCIATED WITH WARM ADVECTION HAVE NOW REACHED INTO
NORTHWEST OHIO. AS AN UPPER LEVEL SHORTWAVE CROSSES THE REGION
EXPECT THESE SHOWERS TO WORK THEIR WAY ACROSS NRN OH AND INTO NW
PA BY MID AFTERNOON. SOME RUMBLES OF THUNDER ARE ALSO POSSIBLE
THIS MORNING...NOT MUCH IN THE WAY OF ELEVATED INSTABILITY.
LATEST HRRR RUNS HAVE A GOOD HANDLE ON THE CURRENT SITUATION AND
HAVE USED THAT AS A GUIDE FOR THIS CURRENT BATCH OF SHOWERS.
ATTEMPTED TO MOVE THE BETTER CHANCES ACROSS THE AREA DURING THE
MORNING AND EARLY AFTERNOON. LATER TODAY NW OHIO WILL BE ABLE TO
RECOVER AND GET SOMEWHAT UNSTABLE. THE UPPER SUPPORT WILL BE
LACKING AND THEREFORE ANY CONVECTION THAT CAN POP UP ALONG A
RECOVERING INSTABILITY AXIS WOULD NOT BE ORGANIZED AND NOT COVER A
LOT OF GROUND. INCREASED PRECIP CHANCES TOWARD TOLEDO BEFORE
EVENING IF ADDITIONAL CONVECTION CAN DEVELOP...AND LINGERED POPS
ELSEWHERE. TEMPERATURES TODAY WILL BE MUCH MILDER....SOLIDLY IN
THE 70S...WITH SPOTS WEST OF CLEVELAND GETTING CLOSE TO 80. EARLY
MORNING UPDATE INCLUDED TWEAKS TO HOURLY TEMPERATURES AND TO
INCREASE PRECIP CHANCE FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
A RATHER WARM AND SOMEWHAT HUMID PERIOD IS EXPECTED WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE SHORT TERM.
THE BIG QUESTION OF WHETHER IT WILL RAIN/THUNDER OVER YOUR HEAD IS
STILL HARD TO ANSWER AND UNFORTUNATELY THE FORECAST STILL REMAINS
FAIRLY GENERIC WITH PRECIP CHANCES THAT FLUCTUATE DIURNALLY. WE
WILL BE IN THE WARM SECTOR AND THERE IS NO LARGE SCALE FORCING TO
INITIATE OR MAINTAIN CONVECTION. OVERALL THE UPPER RIDGE WILL ACT
TO SUPPRESS CONVECTION. AT THE SAME TIME THOUGH MODELS SHOWING AN
INCREASE IN MOISTURE AND QPF. THE QPF IS LIKELY OVERDONE AS HAS
BEEN THE CASE LATELY. IT WILL BE SMALLER SCALE FEATURES THAT WILL
ACT TO INITIATE CONVECTION AND THEREFORE WILL HAVE TO TAKE IT ONE
DAY AT A TIME IN DETERMINING WHO HAS THE BEST CHANCES AND HOW GOOD
OF A CHANCE IT REALLY IS.
IT WILL BE WARM AND MORE HUMID. EXPECT HIGHS OVER THE WEEKEND TO
REACH OR EXCEED 80 AWAY FROM THE LAKE. DEWPOINTS WILL BE NEARING
60 AND NIGHT LOWS WILL BE MILD.
THE COLD FRONT IS EXPECTED TO CROSS MONDAY. HAVE CONTINUED WITH THE
60 PERCENT OR GREATER PRECIP CHANCES WITH THIS SIGNIFICANT
FEATURE...BUT TIMING STILL UNCERTAIN AS IS HOW MUCH ACTIVITY THERE
WILL BE LEADING UP TO IT SUNDAY NIGHT. THE COLD FRONT ITSELF
CROSSES MONDAY EVENING. THERE STILL REMAINS DIFFERENCES ON HOW
MUCH COOL AIR IT BRINGS IN ITS WAKE.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STARTING 12Z TUESDAY A COLD FRONT WILL BE EAST OF THE AREA. HIGH
PRESSURE WILL QUICKLY FILL IN BEHIND THE FRONT...SETTING THE STAGE
FOR STRONG RADIATIONAL COOLING TUESDAY NIGHT. TEMPERATURES WILL FALL
BACK INTO THE LOW 40`S ACROSS THE REGION UNDER A MOSTLY CLEAR SKY.
TUESDAY`S HIGHS WILL STRUGGLE TO GET MUCH ABOVE 60.
BY TUESDAY THE PATTERN BECOMES DE-AMPLIFIED AS AN UPPER LEVEL LOW
SHUFFLES EAST. A BROAD AREA OF HIGH PRESSURE WILL BECOME ESTABLISHED
OVER THE MIDSECTION OF THE COUNTRY AND SPREAD EAST THROUGH THE
REMAINDER OF THE EXTENDED FORECAST. THE WEATHER WILL BE PLEASANT AND
SEASONABLE.
REMOVED SLIGHT CHANCE POPS FROM THE FORECAST ON THURSDAY
AFTERNOON. SHOULD SEE MORE IN THE WAY OF CLOUDS THAN RAIN IN LIGHT
OF ZONAL FLOW ALOFT AND LARGE SURFACE HIGH.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
HIGH CLOUDS WILL CONTINUE TO THIN OVERNIGHT WHILE MID CLOUDS
THICKEN. THE PREVIOUS TAF PACKAGE REMAINS IN GOOD SHAPE AND MADE
ONLY SUBTLE CHANGES WITH THIS ISSUANCE. AN INITIAL WAVE OF MOSTLY
LIGHT RAIN SHOWERS WILL AFFECT MAINLY NORTHWEST OHIO BETWEEN 12
AND 18Z FRIDAY. MORE RECENT MODEL RUNS CONTINUE TO SUGGEST THE
RAIN WILL PETER OUT AS IT MOVES EAST. AFTER 18Z THE ENTIRE AREA
WILL LIKELY SEE SCATTERED THUNDERSHOWERS DEVELOP AHEAD OF A WARM
FRONT. THERE WILL LIKELY BE A LULL IN THE ACTIVITY AFTER 00Z
SATURDAY.
.OUTLOOK...NON VFR AT TIMES IN SHOWERS OR THUNDERSTORMS THRU MON
EVENING.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH ACROSS LAKE ERIE EARLY FRIDAY
AFTERNOON. WAVES WILL GENERALLY BE 3 FEET OF LESS ON THE OPEN WATERS
THROUGH THE WEEKEND WITH SOUTH TO SOUTHWEST FLOW OF 15 KNOTS OR
LESS.
MONDAY NIGHT A COLD FRONT WILL CROSS THE LAKE AND WAVES WILL BUILD
TO 2 TO 4 FEET ON THE OPEN LAKE. BY TUESDAY MORNING THE WIND WILL BE
FROM THE NORTHWEST AT 10 TO 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...MAYERS
AVIATION...MAYERS
MARINE...MAYERS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
945 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST INTO THE REGION TODAY AND
TONIGHT...BRINGING CONSIDERABLE CLOUDINESS THROUGHOUT THE DAY AND
A CHANCE OF SHOWERS BY LATER THIS AFTERNOON. THE FRONT WILL STALL
OVER THE REGION THIS WEEKEND...BRINGING VARIABLE CLOUDS AND A
CHANCE OF SHOWERS EACH AFTERNOON. A COLD FRONT WILL MOVE ACROSS
THE AREA MONDAY NIGHT AND TUESDAY...USHERING IN A COOL AIRMASS
FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE DRIFTING OFF OF THE MID ATLANTIC COAST THIS
MORNING. A FAIRLY VIGOROUS UPPER SHORTWAVE WILL BE MOVING EAST
ACROSS THE LWR GLAKES REGION LATE THIS MORNING...THEN ACROSS NEW
YORK AND NRN PENN THIS AFTERNOON.
A RATHER LARGE AREA OF LGT-MDT RAIN SHOWERS ACROSS SE MICH AND NRN
OHIO AT 1330Z IS PROGGED BY THE HRRR TO BREAK UP A BIT AS IT STREAMS
EAST ACROSS NRN PENN DURING THE AFTERNOON HOURS.
ELSEWHERE...LIGHT WIND AND PERIODS OF SUNSHINE THROUGH THE MID AND
HIGH BKN-OVERCAST LAYER OF CLOUDS WILL DOMINATE THE WEATHER THROUGH
EARLY THIS AFTERNOON ACROSS THE SERN HALF OF THE STATE...WITH
ISOLATED SHRA/TSRA POSSIBLE LATER THIS AFTERNOON AS THE WARM FROM
APPROACHES FROM THE OHIO VALLEY.
INCREASING HUMIDITY/INSTABILITY ASSOC WITH ARRIVAL OF THE WARM FRONT
WILL RESULT IN BUILDING CU BY AFTN ACROSS THE ALLEGHENY PLATEAU
ALONG WITH SCT PM CONVECTION. BEST OVERALL CHC OF RAIN /70-80
PERCENT/ THIS AFTERNOON APPEARS TO BE OVR THE NW MTNS...CLOSEST TO
TRACK OF NEXT SHORTWAVE CROSSING OVR THE E GRT LKS. HAVE MODIFIED
POPS UPWARD A BIT ACROSS NRN PENN AFTER 18Z...BUT LEFT LOW POPS OF
ONLY ARND 15 PCT FOR A LATE DAY SHRA ACROSS THE SE COUNTIES...WHERE
AIR MASS WILL REMAIN RELATIVELY STABLE EAST OF FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WARM FRONT GETS HUNG UP ACROSS N CENTRAL TONIGHT AS FLAT RIDGE
CONTINUES TO BE IMPACTED BY EMBEDDED SHORTWAVE TROFS. THIS WILL
KEEP CHC OF SHOWERS GOING...ALTHOUGH MUCH OF THE TIME WILL BE RAIN
FREE IN MOST AREAS. BEST CHC FOR SHOWERS WILL COME SATURDAY
AFTERNOON OVER THE WESTERN AND NORTHERN HIGH TERRAIN AS CAPES GROW
TO SEVERAL HUNDRED J/KG AND BOUNDARY PROVIDES A FOCUS/TRIGGER FOR
INITIATION. MINS TONIGHT WILL BE MILD...GENERALLY RANGING FROM THE
UPPER 50S NORTH THROUGH THE 60S SOUTH. HIGHS ON SATURDAY WILL
RANGE FROM THE MID 70S NORTH TO AROUND 80 SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE SURFACE LOW REACHING THE UPPER MIDWEST BY EARLY FRIDAY WILL BE
PRECEDED BY A WARM FRONT AS IT CROSSES THE GREAT LAKES/OH VALLEY
AND REACHES THE MID ATLANTIC AND NORTHEAST STATES BY THIS
WEEKEND. A SUFFICIENT INCREASE IN MOISTURE (PWS) AND INSTABILITY
WILL SUPPORT SCATTERED CONVECTION INTO EARLY NEXT WEEK WITH THE
WARM FRONT AND ALSO WITH A TRAILING SURFACE TROUGH EXTENDING
TOWARD THE NORTHERN APPALACHIANS PROVIDING SOME ADDITIONAL LIFT.
A WELL-DEFINED COLD FRONT SHOULD CROSS THE REGION LATER MONDAY
INTO EARLY TUESDAY WITH THE GREATEST RISK FOR WIDESPREAD SHOWERS
AND T-STORMS. THE PARENT SHORTWAVE TROUGH WILL SUPPRESS THE ERN
RIDGE AND ALLOW COOLER/DRIER AIR TO ARRIVE BY MIDWEEK...AS HIGH
PRESSURE SETTLES SEWD FROM THE UPPER PLAINS INTO THE MID ATLC.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/... VARIABLE AMOUNTS/THICKNESS
OF MID AND HIGH CLOUDS WILL OCCUR TODAY ACROSS MUCH OF CENTRAL AND
SERN PENN...AHEAD OF A WARM FRONT LIFTING NE FROM THE OHIO RIVER
VALLEY. ACROSS OUR NW/NCENT MTN ZONES...CLOUDS WILL LOWER AND
THICKEN TODAY...THOUGH THE MAINLY MID CLOUD DECK SHOULD REMAIN IN
THE VFR RANGE THROUGH MOST OF THE DAY.
LATEST HI RESOLUTION MODEL RUNS BRING IN THE SHOWERS THROUGH NWRN
PA BEGINNING AROUND 18Z AND MOVING EASTWARD THROUGH 00Z
/IMPACTING TAF SITES MAINLY ALONG AND NORTH OF A KDUJ TO KIPT
LINE...OR NORTH OF INTERSTATE 80/.
MVFR TO IFR POSSIBLE IN ANY OF THE SHOWERS AND THUNDERSTORMS. THE
CHANCES FOR RESTRICTING CONDITIONS WILL CONTINUE TO INCREASE FRIDAY
NIGHT INTO SATURDAY MORNING.
OUTLOOK...
SAT-TUE...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOCAL REDUCTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DEVOIR
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
901 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST INTO THE REGION TODAY AND
TONIGHT...BRINGING CONSIDERABLE CLOUDINESS THROUGHOUT THE DAY AND
A CHANCE OF SHOWERS BY LATER THIS AFTERNOON. THE FRONT WILL STALL
OVER THE REGION THIS WEEKEND...BRINGING VARIABLE CLOUDS AND A
CHANCE OF SHOWERS EACH AFTERNOON. A COLD FRONT WILL MOVE ACROSS
THE AREA MONDAY NIGHT AND TUESDAY...USHERING IN A COOL AIRMASS
FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE DRIFTING OFF OF THE MID ATLANTIC COAST THIS
MORNING. A FAIRLY VIGOROUS UPPER SHORTWAVE WILL BE MOVING EAST
ACROSS THE LWR GLAKES REGION LATE THIS MORNING...THEN ACROSS HEW
YORK AND NRN PENN THIS AFTERNOON.
A RATHER LARGE AREA OF MDT RAIN SHOWERS ACROSS SE MICH AND NRN
OHIO IS PROGGED BY THE HRRR TO BREAK UP A BIT AS STREAM EAST
ACROSS NRN PENN DURING THE AFTERNOON HOURS. ELSEWHERE...
SOME BREAK IN THE MID AND HIGH OVERCAST WILL DOMINATE THE WEATHER
THROUGH EARLY THIS AFTERNOON ACROSS THE SERN HALF OF THE STATE
WITH ISOLATED SHRA/TSRA POSSIBLE LATER THIS AFTERNOON AS THE WARM
FROM APPROACHES FROM THE OHIO VALLEY.
INCREASING HUMIDITY/ INSTABILITY ASSOC WITH ARRIVAL OF WARM FRONT
WILL RESULT IN BUILDING CU BY AFTN ACROSS THE ALLEGHENY PLATEAU
ALONG WITH SCT PM CONVECTION. BEST CHC OF RAIN WOULD APPEAR TO BE
OVR THE NW MTNS...CLOSEST TO TRACK OF NEXT SHORTWAVE CROSSING OVR
THE E GRT LKS. HAVE MODIFIED POPS UPWARD A BIT ACROSS NRN PENN
AFTER 18Z...BUT LEFT LOW POPS OF ONLY ARND 15 PCT FOR A LATE DAY
SHRA ACROSS THE SE COUNTIES...WHERE AIR MASS WILL REMAIN
RELATIVELY STABLE EAST OF FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WARM FRONT GETS HUNG UP ACROSS N CENTRAL TONIGHT AS FLAT RIDGE
CONTINUES TO BE IMPACTED BY EMBEDDED SHORTWAVE TROFS. THIS WILL
KEEP CHC OF SHOWERS GOING...ALTHOUGH MUCH OF THE TIME WILL BE RAIN
FREE IN MOST AREAS. BEST CHC FOR SHOWERS WILL COME SATURDAY
AFTERNOON OVER THE WESTERN AND NORTHERN HIGH TERRAIN AS CAPES GROW
TO SEVERAL HUNDRED J/KG AND BOUNDARY PROVIDES A FOCUS/TRIGGER FOR
INITIATION. MINS TONIGHT WILL BE MILD...GENERALLY RANGING FROM THE
UPPER 50S NORTH THROUGH THE 60S SOUTH. HIGHS ON SATURDAY WILL
RANGE FROM THE MID 70S NORTH TO AROUND 80 SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE SURFACE LOW REACHING THE UPPER MIDWEST BY EARLY FRIDAY WILL BE
PRECEDED BY A WARM FRONT AS IT CROSSES THE GREAT LAKES/OH VALLEY
AND REACHES THE MID ATLANTIC AND NORTHEAST STATES BY THIS
WEEKEND. A SUFFICIENT INCREASE IN MOISTURE (PWS) AND INSTABILITY
WILL SUPPORT SCATTERED CONVECTION INTO EARLY NEXT WEEK WITH THE
WARM FRONT AND ALSO WITH A TRAILING SURFACE TROUGH EXTENDING
TOWARD THE NORTHERN APPALACHIANS PROVIDING SOME ADDITIONAL LIFT.
A WELL-DEFINED COLD FRONT SHOULD CROSS THE REGION LATER MONDAY
INTO EARLY TUESDAY WITH THE GREATEST RISK FOR WIDESPREAD SHOWERS
AND T-STORMS. THE PARENT SHORTWAVE TROUGH WILL SUPPRESS THE ERN
RIDGE AND ALLOW COOLER/DRIER AIR TO ARRIVE BY MIDWEEK...AS HIGH
PRESSURE SETTLES SEWD FROM THE UPPER PLAINS INTO THE MID ATLC.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
CLOUDS CONTINUE TO THICKEN TODAY THROUGH CLOUD DECKS SHOULD REMAIN
IN THE VFR RANGE THROUGH MOST OF THE DAY. LATEST MODEL RUNS BRING
IN THE SHOWERS THROUGH CENTRAL PA BEGINNING AROUND 18Z AND MOVING
EASTWARD THROUGH 00Z. VFR SHOULD STILL DOMINATE WITH MVFR TO IFR
POSSIBLE IN THE SHOWERS AND THUNDERSTORMS.THE CHANCES FOR
RESTRICTING CONDITIONS WILL CONTINUE TO INCREASE FRIDAY NIGHT INTO
SATURDAY MORNING.
OUTLOOK...
SAT-TUE...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOCAL REDUCTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DEVOIR
LONG TERM...STEINBUGL
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1046 AM CDT FRI MAY 15 2015
.UPDATE...
LATEST RADAR SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS GETTING
READY TO PUSH INTO PORTIONS OF NORTHEAST ARKANSAS. MEANWHILE...A
FEW SHOWERS HAVE BEEN DEVELOPING OVER NORTHEAST MISSISSIPPI AND
PORTIONS OF WEST TENNESSEE NEAR THE TENNESSEE RIVER OVER THE PAST
HOUR. LATEST HRRR SHOWS SHOWER AND THUNDERSTORM DEVELOPMENT WILL
EXPLODE OVER THE MIDSOUTH BY 1-2 PM AS A SHORTWAVE MOVES INTO THE
AREA. CURRENT POPS OF 60 LOOK GOOD AS WELL AS THE REST OF THE
FORECAST. NO UPDATES ARE EXPECTED.
KRM
&&
.DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE EARLY MORNING
BEFORE SHOWERS AND THUNDERSTORMS DEVELOP ACROSS ALL TERMINALS.
SOMEWHAT DIFFICULT TO TIME THIS ACTIVITY AS SOME UNCERTAINTY STILL
EXISTS BUT DO EXPECT ISOLATED TO SCATTERED TSTORMS TO MOVE INTO
ALL TERMINALS BY 16-18Z. PRECIPITATION WILL LAST THROUGH MUCH OF
THE NEXT 24 HOURS WITH SHOWERS CONTINUING OFF AND ON THROUGH
FRIDAY NIGHT. CIGS MAY LOWER INTO THE MVFR CATEGORY EARLY SATURDAY
MORNING.
TVT
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
617 AM CDT FRI MAY 15 2015
.UPDATE...
UPDATED AVIATION DISCUSSION FOR 12Z TAFS...
&&
.PREV DISCUSSION... /ISSUED 425 AM CDT FRI MAY 15 2015/
DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE EARLY MORNING
BEFORE SHOWERS AND THUNDERSTORMS DEVELOP ACROSS ALL TERMINALS.
SOMEWHAT DIFFICULT TO TIME THIS ACTIVITY AS SOME UNCERTAINTY STILL
EXISTS BUT DO EXPECT ISOLATED TO SCATTERED TSTORMS TO MOVE INTO
ALL TERMINALS BY 16-18Z. PRECIPITATION WILL LAST THROUGH MUCH OF
THE NEXT 24 HOURS WITH SHOWERS CONTINUING OFF AND ON THROUGH
FRIDAY NIGHT. CIGS MAY LOWER INTO THE MVFR CATEGORY EARLY SATURDAY
MORNING.
TVT
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1044 AM CDT FRI MAY 15 2015
.DISCUSSION...BASED ON CURRENT RADAR TRENDS WHICH SHOW AN
INCREASING PUSH TO THE ESE...AND HRRR/NSSL OUTPUT...HAVE INCREASED
POPS ACROSS THE ERN HALF OF THE CWA FOR THIS AFTERNOON. ALSO
INCREASED QPF UP TO HALF AN INCH FOR AVGS...BUT LOCAL AMOUNTS
COULD BE MUCH HIGHER. THE HRRR PROGS AROUND 3-5 INCHES ACROSS THE
COASTAL BEND THIS AFTERNOON. UPDATES WILL BE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 750 AM CDT FRI MAY 15 2015/
DISCUSSION...UPDATED TO GO WITH A FFA ACROSS ALL OF THE CWA
TODAY. EVEN IF RAINFALL DECREASES AS IT MOVES FARTHER EAST THIS
AFTERNOON...IT WILL NOT TAKE MUCH TO CAUSE ADDITIONAL FLOODING
PROBLEMS ACROSS AREAS ALREADY SATURATED AND FLOODED. AN MCS HAS
DVLPD ACROSS THE NW CWA AND SEVERAL MODELS SHOW THIS PROGRESSING
EAST THROUGH THE DAY. ALSO CAN NOT RULE OUT SEVERE WX GIVEN THE
UPPER SHORT WAVE...INSTABILITY AND THE ABUNDANT MOISTURE.
PREV DISCUSSION... /ISSUED 619 AM CDT FRI MAY 15 2015/
DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...MVFR CIGS WERE MAINLY OVER THE BRUSH COUNTRY...NOT
AS PREVALENT OVER THE COASTAL PLAINS. WILL KEEP A MENTION OF
LOWER CIGS IN TEMPO GROUP FOR COASTAL SITES THIS MORNING ALONG
WITH PATCHY FOG FOR ALI/VCT.
SATELLITE IMAGERY SHOWS THE STRONG UPPER TROUGH MOVING THROUGH
COAHUILA INTO THE RIO GRANDE PLAINS EARLY THIS MORNING. THE
CONVECTION HAS NOT FORMED AS MUCH OVER NORTHEAST MEXICO WHILE
ACTIVITY NORTHWEST OF COTULLA REMAINS STRONG. THIS ACTIVITY WILL
MOVE EAST INTO THE WESTERN BRUSH COUNTRY DURING THE EARLY MORNING
HOURS. EXPECT SCATTERED STORMS TO FORM OVER COASTAL BEND LATER
THIS MORNING INTO THE AFTERNOON HOURS.
CONVECTION SHOULD DIMINISH OVER THE BRUSH COUNTRY BY EARLY
AFTERNOON WHILE DIMINISHING TREND WILL NOT OCCUR UNTIL LATE
AFTERNOON FOR COAST. MVFR CIGS WILL MOVE BACK INTO THE REGION
EARLY FRIDAY EVENING. EXPECT IFR CIGS WILL OCCUR FOR COASTAL
SITES BY MIDNIGHT AND CONTINUE THROUGH THE NIGHT.
PREV DISCUSSION... /ISSUED 419 AM CDT FRI MAY 15 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...CONVECTION HAS PERSISTED
BETWEEN COTULLA AND UVALDE EARLY THIS MORNING BUT ACTIVITY LOOKS
LIKE IT IS STARTING TO MOVE. WATER VAPOR IMAGERY SHOWS A STRONG
SHORT WAVE TROUGH MOVING INTO THE TEXAS BIG BEND/COAHUILA AHEAD
OF THE DEEP CLOSED LOW MOVING INTO THE GREAT BASIN. EXPECT THIS
SHORT WAVE TROUGH WILL TRACK NORTHEAST ACROSS THE AREA TODAY AND
BE NORTHEAST OF THE AREA BY LATE AFTERNOON. THE BLENDED TOTAL
PRECIPITABLE WATER IMAGE EARLIER THIS MORNING SHOWED THE DEEPER
MOISTURE AXIS ALONG THE RIO GRANDE WITH VALUES BETWEEN 1.7-1.9
INCHES. MOST OF THE MODELS DEVELOPED EXPANSIVE AREA OF CONVECTION
AHEAD OF THIS SHORT WAVE TROUGH OVER NORTHEAST MEXICO EARLY THIS
MORNING...WHICH MOST OF THE HI-RES MODELS MOVED THROUGH SOUTH
TEXAS TODAY. BUT ACTIVITY OVER NORTHEAST MEXICO ONLY ISOLATED
BUT SHOULD SEE CONVECTION INCREASE AS UPPER LEVEL SUPPORT FROM
THE WEST ARRIVES OVER BETTER MOISTURE ALONG THE RIO GRANDE.
WILL CONTINUE WITH LIKELY POPS OVER THE BRUSH COUNTRY WITH A
MENTION OF LOCALLY HEAVY RAIN POSSIBLY THIS MORNING. CONTEMPLATED
ISSUING A FLASH FLOOD WATCH FOR THE BRUSH COUNTRY AS ANY AMOUNT
OF HEAVY RAIN OVER SATURATED GROUNDS WILL BECOME RUNOFF. BUT
SPEED OF SHORT WAVE TROUGH MOVING THROUGH THE AREA AND SOMEWHAT
LOWER CONFIDENCE DUE TO MESO-SCALE MODELS HANDLING OF CURRENT
TREND...WILL HOLD OFF ON WATCH. KEPT SLIGHT CHANCE POPS IN FOR
THIS EVENING...BUT EXPECT LIMITED RAIN CHANCES OVERNIGHT INTO
SATURDAY MORNING. AFTER SHORT WAVE TROUGH GOES BY...MID LEVEL
WARMING OCCURS STRENGTHENING THE CAP. THE UPPER LOW OVER THE
GREAT BASIN MOVES NORTHEAST ACROSS THE FOUR CORNERS REGION ON
SATURDAY. A WEAK SHORT WAVE TROUGH WILL MOVE OUT OF NORTHERN
MEXICO WITH THE POSSIBILITY OF AN UPPER LEVEL JET STREAK NOSING
INTO THE BRUSH COUNTRY IN THE AFTERNOON. AIR MASS WILL BE CAPPED
FOR MOST OF THE DAY. BUT WITH STRONG HEATING...COULD SEE THE CAP
BROKEN WITH ISOLATED TO SCATTERED STRONG CONVECTION DEVELOP BY
MID-LATE AFTERNOON OVER THE BRUSH COUNTRY INTO THE INLAND
PORTIONS OF THE COASTAL BEND.
MARINE...LOW PRESSURE WILL BE DEEPENING OVER THE SOUTHERN AND
CENTRAL HIGH PLAINS TONIGHT INTO SATURDAY AS THE UPPER LOW OVER
GREAT BASIN APPROACHES. ONSHORE FLOW WILL INCREASE TO MODERATE
OVER THE COASTAL WATERS TONIGHT INTO SATURDAY. SCEC CONDITIONS
WILL EXIST FOR THIS PERIOD...MAY EVEN APPROACH SCA CONDITIONS
AT TIMES.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...ANY CONVECTION FROM
THE DAYTIME HOURS SATURDAY SHOULD QUICKLY DIMINISH BY SATURDAY
EVENING AS S/W DISTURBANCE SHIFTS TO THE NE OF THE CWA AND DRIER AIR
AT H85 TRIES TO BUILD INTO THE REGION FROM THE SOUTHEAST. ON
SUNDAY...ANOTHER MID LEVEL S/W TROUGH CAUGHT IN THE SW FLOW WILL
SKIRT NE ACROSS THE REGION WHILE AT THE SAME TIME UPPER LEVEL
DIVERGENCE IS PROG TO INCREASE...ESPECIALLY ACROSS NORTHERN AND
WESTERN COUNTIES. CLOSER THE SURFACE...A WEAK SURFACE BOUNDARY IS
PROG TO SHIFT INTO THE EDWARDS PLATEAU WITH CONVECTION LIKELY
IGNITING ALONG THE BOUNDARY TO OUR NORTH...WITH ADDITIONAL
CONVECTION DEVELOPING ACROSS THE CWA AS DIURNAL INSTABILITY
INCREASES AND DYNAMICS ALOFT IMPROVE. HAVE CHANCE POPS FOR
CONVECTION SUNDAY /ESPECIALLY IN THE AFTERNOON/ WITH CONVECTION
POSSIBLY PERSISTING INTO THE EVENING HOURS AS LLVL MOISTURE INFLUX
INCREASES. SFC BOUNDARY WASHES OUT/SHIFTS FARTHER N ON MONDAY WITH
UPPER LEVEL DIVERGENCE SHIFTING N AS WELL. THUS...PRECIP CHANCES ON
MONDAY SHOULD REMAIN LOW...THOUGH NOT NIL. MID/UPPER LEVEL RIDGING
BUILDS INTO THE REGION FOR MID WEEK WITH LLVL DRIER AIR /JUST ABOVE
THE SFC/ BUILDING IN FROM THE WESTERN GULF...AND THUS PRECIP CHANCES
WILL BE VERY LOW TO NON MENTIONABLE. DESPITE HIGH SOIL MOISTURE
LEVELS...MAX TEMPS HAVE BEEN REACHING GUIDANCE LEVELS PAST COUPLE OF
DAYS...AND WITH SOME RIDGING EXPECTED BY MID WEEK I AM EXPECTING MAX
TEMPS TO WARM FURTHER /90S NEARLY AREAWIDE/ IN THE EXTENDED PERIOD.
MIN TEMPS WILL CONTINUE TO BE ABOVE NORMAL FOR THIS TIME OF YEAR
GIVEN NOCTURNAL CLOUD COVER AND HUMID CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 85 76 87 77 88 / 80 20 20 10 30
VICTORIA 84 73 87 75 88 / 80 20 20 10 40
LAREDO 88 75 94 75 94 / 70 20 20 10 40
ALICE 86 75 90 75 91 / 80 20 30 10 40
ROCKPORT 83 77 86 78 87 / 80 10 20 10 30
COTULLA 85 73 90 73 90 / 80 20 30 10 40
KINGSVILLE 86 76 89 77 89 / 80 20 20 10 40
NAVY CORPUS 83 78 85 78 86 / 80 20 20 10 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...JIM
WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...NUECES...
REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...NONE.
&&
$$
TE/81...SHORT TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
946 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 946 AM EDT FRIDAY...
ADJUSTED TEMPERATURES AND DEWPOINTS WITH THE LATEST OBS AND MODEL
TRENDS. MODIFIED CLOUD COVER TOWARDS LATEST SATELLITE IMAGE AND
TRENDED LATE MORNING INTO THIS AFTERNOON TOWARDS A BLEND OF THE
CANADIAN AND HRRR...WHICH CAPTURE THE SUNSHINE ACROSS SOUTHEAST
WEST VIRGINIA AND NEW RIVER VALLEY WITH RICHER CLOUDS ALONG THE
SOUTHERN BLUE RIDGE. HEATING WILL CREATE INSTABILITY COMBINED WITH
CAPES OF AROUND 500 TO 1000 J/KG TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS. DAY ONE CONVECTIVE OUTLOOK PLACES THE SEVERE
THREAT TO OUR WEST. ALLOWED FOR LIGHT SHOWERS ALONG THE SOUTHERN
BLUE RIDGE THEN SHAPED POPS FOR LATE THIS MORNING INTO THIS
AFTERNOON TOWARDS A HRRR/RNK WRFARW. HIGH TEMPERATURES THIS
AFTERNOON WILL RANGE FROM THE UPPER 60S IN THE MOUNTAINS TO AROUND
80 DEGREES IN THE PIEDMONT.
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
749 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
747 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
622 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI MAY 15 2015
BIGGEST CHANGE TO THIS PERIOD WILL BE TO REMOVE THE SEVERE STORM
POTENTIAL OVERNIGHT CURRENTLY IN THE SERVICE SUITE.
SATELLITE AND SURFACE OBSERVATIONS SHOWING A VERY WEAK PRESSURE
GRADIENT AND LOW CLOUD AND FOG FAIRLY WIDESPREAD ACROSS THE
REGION IN THE WAKE OF THE RAIN. STILL SOME DRIZZLE BEING REPORTED
IN WI IN WHAT THE RAP SOUNDINGS INDICATE AS A 2KM DEEP MOIST
LAYER. SPORADIC REPORTS OF NEAR ZERO VISIBILITY ARE OUT THERE AS
OF 08Z /MAINLY IOWA/...BUT WEB CAMERAS ACROSS THE AREA DONT REVEAL
WIDESPREAD REDUCTIONS TO VISIBILITY. OVERALL IDEA TODAY IS
SHORTWAVE RIDGING BUILDING IN AND DEEPER MIXING...BUT HAVE TAKEN A
PESSIMISTIC APPROACH WITH MORE SUN SEEN IN THE AFTERNOON. WILL
CONTINUE TO MONITOR FOR MORE WIDESPREAD FOG ISSUES AND FOR NOW
WILL HANDLE THIS WITH SPECIAL WX STATEMENTS.
PREVIOUS FORECAST AND CURRENT MESSAGING CONTAINS A SEVERE RISK
OVERNIGHT AS THE WARM FRONT...NOW LOCATED ROUGHLY ALONG
I-80...LIFTS INTO THE AREA. A SECONDARY MARITIME TROPICAL AIRMASS
RESIDES SOUTH OF I-70 WITH 65-70F DEWPOINTS...NOT TOO FAR AWAY.
THE 15.00Z NAM IS REALLY THE OUTLIER ON THE MUCAPE FORECAST INTO
THE AREA /THROUGH ITS ENTIRE FORECAST/ AND FEEL IT MUST BE REDUCED
ABOUT 30 PERCENT BASED ON SOUNDINGS AND LATEST MODEL CONSENSUS. AS
THE SPOKE OF ENERGY FROM THE SWRN U.S. LONG WAVE TROUGH ROTATES
NORTH //NOW IN NM/AZ//...HEIGHTS WILL FALL IN THE LOW-LEVELS AND
THE MOISTURE TRANSPORT WILL ENHANCE IN THE DAKOTAS/WRN MN...BUT
PRETTY FAR WEST. BY THE THE OVERNIGHT HOURS...AN AXIS OF MOISTURE
CONVERGENCE AND ABOUT 500 J/KG OF MUCAPE WILL RUN FROM KABR-KLSE.
BETTER CONVERGENCE ALONG THE WARM FRONT IN THE LOW LEVELS WILL BE
OCCURRING FURTHER WEST. HAVE KEPT 30S PERCENT CHANCES FOR THAT
PERIOD FOR THUNDERSTORMS...BUT THE WIND SHEAR IS VERY LOW AND THE
LESS AGGRESSIVE MODELS WITH MOISTURE /15.00Z GFS/ SUGGEST SOME
CAPPING OF 50-80J IS IN PLACE FOR 1-2KM PARCELS BEING LIFTED. SO
COVERAGE OF STORMS IS ALSO IN QUESTION. OVERALL...DIDNT SEE AN
ORGANIZED THREAT TO SPEAK OF FOR MESSAGING IN OUR SERVICE. WILL BE
PULLING THAT MENTION. SPC DAY 1 OUTLOOK WOULD AGREE WITH THIS
ASSESSMENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI MAY 15 2015
SATURDAY WILL SEE WARMER CONDITIONS AS THE WARM FRONT SHIFTS FURTHER
NORTH INTO THE NORTHERN FORECAST AREA AND NRN WI. DEWPOINTS AND
CAPE WILL BE ON THE INCREASE AND PROBABLY ABOUT 1000 J/KG OF
MLCAPE WILL BE PRESENT IN THE AFTERNOON. HOWEVER...FORCING IS
MINIMAL DURING PEAK HEATING WITH FAIRLY UNIFORM S-SE FLOW IN THE
FORECAST AREA IN THE WARM SECTOR. THE WILD CARD MAY BE ANY
CONVECTIVE VORTICITY THAT IS GENERATED IN THE SRLY FLOW. HAVE LEFT
SMALL RAIN CHANCES IN THE AFTERNOON. IT COULD BE A WARM DAY
SATURDAY AND BUMPED HIGHS A BIT WITH 19-21C SUGGESTED AT 925MB
FROM THE 15.00Z GUIDANCE /4-5C WARMER THAN FRIDAY/.
THE BIG STORY CONTINUES TO BE THE SUNDAY POTENTIAL FOR SEVERE
STORMS. POTENTIAL IS A GOOD WORD AS IT COULD BE A FAVORABLE DAY
FOR TORNADOES...BUT ALSO COULD RAIN THROUGH THE MORNING AND TURN
INTO NO STORY. THERE IS A BIG DIFFERENCE BETWEEN THE
DETERMINISTIC GUIDANCE WITH THE 15.00Z AND 14.18Z NAM RUNS SUGGESTING
A GOOD SETUP FOR SUPERCELL TORNADOES AND THE OVERALL SYNOPTICS AND
TIMING. HOWEVER...IT IS AN OUTLIER AS THE 15.00Z ECMWF/GFS AND
15.03Z/21Z SREFS ALL SUGGEST A DIFFERENT OUTCOME. THAT OUTCOME
WOULD INCLUDE STRONG MOISTURE TRANSPORT CONVERGENCE COMING INTO
THE AREA EARLY ON SUNDAY FROM THE WEST /SUNRISE/ AND SHIFTING EAST
ACROSS THE AREA. THERE WOULD PROBABLY BE ENOUGH INSTABILITY AND
INCREASING DEEPER STRONGER SHEAR FOR SOME MARGINALLY SEVERE
STORMS THEN. POSSIBLY A SMALL WINDOW IN WI FOR SEVERE STORMS TO
REDEVELOP LATER...BUT THIS SEEMS TO SHIFT NORTHEAST QUICKLY. THE
SLOWER 15.00Z AND 14.18Z NAM RUNS SUGGEST A SLOWER TIMING AND LESS
MORNING CONVECTION INTO WI...FAVORING A BETTER SUNDAY AFTERNOON
SEVERE STORM OUTBREAK.
IMPORTANTLY...SUNDAY HAS EXCELLENT DEEP SHEAR THROUGH 10KM...AND
TIMING AND INSTABILITY ARE THE MAIN PROBLEMS THAT NEED RESOLUTION. SPC
DAY 3 DISCUSSION MAINTAINS THE SLIGHT RISK OVER THE AREA...WHICH
SEEMS ON TRACK FOR THE DIFFERENCES THAT REMAIN ON SUNDAYS OUTCOME.
IT IS ONLY FRIDAY MORNING...AND THESE SWRN U.S. SYSTEMS ARE VERY
DEPENDENT ON THE ENERGY OVER THE PACIFIC BEING RESOLVED CORRECTLY
BY THE MODEL INITIALIZATION. THE NAM SKILL IN THE OUTER HOURS IS
NOT AS FAVORABLE AS WITHIN A DAY. WILL TRY TO STRESS THAT
DIFFERENCES EXIST ON HOW SUNDAY COULD PLAY OUT...BUT THAT A RISK
OF ORGANIZED SEVERE WEATHER EXISTS.
MONDAY THROUGH THURSDAY...AFTER THIS DEEPENING LOW AND SHOWER
CHANCES SHIFT EAST...THE WEEK SHOULD HAVE SLIGHTLY BELOW NORMAL
TEMPERATURES AND MAINLY DRY UNDER CONFLUENT NORTHWEST FLOW AND
CANADIAN SOURCED HIGH PRESSURE. COLDEST DAYS WILL BE MONDAY AND
TUESDAY...THEN SOME RISE EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 622 AM CDT FRI MAY 15 2015
MVFR/IFR CIGS/VSBYS ACROSS THE AREA EXPECTED TO GIVE WAY TO VFR
CONDITIONS THRU THE MORNING AS SOME DRYING NORTHWEST LOW LEVEL
FLOW...DIURNAL WARMING/MIXING AND A SFC-850MB RIDGE AXIS MOVES OVER
MN/WI. SCT MAINLY VFR LOWER CLOUDS EXPECTED BY EARLY AFTERNOON...
UNDER A BKN-OVC CIRRUS DECK. CIRRUS DECK SET TO THICKEN TONIGHT...
AND LOOKS TO HELP KEEP LOWER CLOUDS MORE SCT THRU TONIGHT. LOWER
MOISTURE DOES INCREASE LATER TONIGHT AS A WARM FRONT LIFTS NORTH
TOWARD THE TAF SITES AND LOWER LEVEL WINDS SWING BACK TO THE
SOUTHEAST. MAY BE SOME SHRA/TSRA IN THE AREA LATE TONIGHT AS THE
WARM FRONT APPROACHES. HOWEVER...WITH ONLY ISOLATED TO WIDELY SCT
COVERAGE EXPECTED AND CONFIDENCE IN ANY SHRA/TSRA CHANCES LATE
TONIGHT NOT THE HIGHEST...LEFT MENTION OF THEM OUT OF THE LAST 3 TO
6 HRS OF THE TAF FOR NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
557 AM MDT FRI MAY 15 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT FRI MAY 15 2015
SHOWERS AND A FEW STRONG THUNDERSTORMS HAVE BEEN ONGOING FOR MUCH OF
THE NIGHT OVER THE PLAINS. THIS IS IN RESPONSE TO STRONG LLVL THETA-
E ADVECTION NORTH OF A STATIONARY BOUNDARY DRAPED FROM WEST TO EAST
ALONG THE I-80 CORRIDOR. BUFKIT SOUNDINGS FROM THE RAP MODEL SHOW UP
TO 500 J/KG OF MUCAPE TO THE NORTH OF THIS BOUNDARY...WHICH COMBINED
WITH MODEST DEEP LAYER VERTICAL SHEAR IS CONTRIBUTING TO SOME SMALL
HAIL PRODUCTION. ISSUED A FEW SPS PRODUCTS THIS MORNING TO HIGHLIGHT
THE STRONGEST CELLS...BUT EVERYTHING IS STAYING SUB-SEVERE. AIR MASS
ACROSS MUCH OF SOUTHEAST WYO/WESTERN NEB IS BECOMING VERY MOIST THIS
MORNING WITH LLVL EASTERLY/UPSLOPE FLOW. DEWPOINTS OVER WESTERN NEB
WERE ALREADY IN THE 50-55 F RANGE AT 10Z...AND THESE ARE EXPECTED TO
BE ADVECTED WESTWARD ALONG THE LARAMIE RANGE WITH TIME AS STRONG SFC
CYCLOGENESIS OVER EASTERN CO KEEPS NEAR-SFC FLOW BACKED OVER OUR CWA
THROUGH THE DAY. FORECAST SOUNDINGS AND THE OPERATIONAL HRRR SHOW AT
LEAST SOME POTENTIAL FOR FOG OVER THE PLAINS THROUGH 15Z. HOWEVER...
WIDESPREAD SHOWER ACTIVITY SHOULD KEEP THE BOUNDARY LAYER MIXED. WE
DECIDED TO REMOVE MENTION OF FOG FROM THE GRIDS AS ANY REDUCED VSBYS
WOULD BE QUITE ISOLATED.
ATTENTION THEN SHIFTS TO A MORE WIDESPREAD...POTENTIALLY SIGNIFICANT
SEVERE WEATHER EPISODE EVOLVING LATER TODAY. WE WILL REALLY NEED TO
WATCH THE POSITION OF THE SURFACE LOW TODAY AS LLVL WIND FIELDS WILL
PLAY A SIGNIFICANT ROLE IN CONVECTIVE MODE AND STORM INTENSITY. THE
GFS IS STILL AN APPARENT OUTLIER WITH 18-00Z POSITIONING OF A 995 MB
SURFACE LOW LIFTING OUT OF NORTHEAST CO. NOTHING UNUSUAL FOR THE GFS
AS THIS MODEL DOES HAVE A TENDENCY TO PUSH SURFACE FEATURES EASTWARD
TOO QUICKLY. THE NET RESULT IS THE DEVELOPMENT OF WESTERLY FLOW NEAR
THE SURFACE OVER MOST OF THE CWA BY AROUND 21Z. THE PREFERRED SOLNS
ARE STILL THE ECMWF AND NAM WITH THE SLOWER PROGRESSION...AND LONGER
RESIDENCE TIME OF EASTERLY FLOW EAST OF THE LARAMIE RANGE. THE BIG
QUESTIONS RIGHT NOW WILL BE ONGOING CONVECTION/LOW CLOUDS AND THEIR
OVERALL IMPACT ON INSTABILITY PARAMETERS. MORNING WATER VAPOR SHOWS
A MID LEVEL DRY SLOT MOVING INTO EASTERN CO...AND CLOUD TOPS ON THE
LATEST IR LOOP HAVE BEEN WARMING OVER THE LAST FEW HOURS. THUS...DO
NOT EXPECT PCPN TO BE A MAJOR INHIBITING FACTOR. STRONGLY DIFLUENT
FLOW ALOFT IS NOW DEVELOPING ACROSS THE CWA AHEAD OF A VIGOROUS LOW
OVER CA/NV...ALONG WITH A COUPLED H25 JET. MOST CONVECTION-ALLOWING
MODELS SHOW CIN ERODING ENTIRELY BY 18Z...SO STRONGLY BELIEVE THIS
WILL BE AN EARLY SHOW WITH TSTMS BECOMING WIDESPREAD BY AFTN. H7
TEMPS AROUND +7 DEG C OVER THE PANHANDLE WOULD SUGGEST CAPPING AND
LESS COVERAGE THERE. THE AFOREMENTIONED SURFACE BOUNDARY WILL LIFT
NORTHWARD AS A WARM FRONT LATER TODAY...SO THIS WILL SERVE AS THE
PRIMARY FOCUS FOR INITIATION AS WELL AS ENHANCED CONVERGENCE ALONG
THE LARAMIE RANGE.
ENVIRONMENTAL PARAMETERS CONTINUE TO SUGGEST INCREASING POTENTIAL
FOR DANGEROUS THUNDERSTORMS ALONG/EAST OF THE LARAMIE RANGE. GOOD
INSOLATION AND DEW POINTS IN THE MID 50S BENEATH VERY STEEP MID
LEVEL LAPSE RATES SHOULD YIELD SBCAPE OF 2000-3000 J/KG INVOF THE
WARM FRONT. 0 TO 6 KM SHEAR OVER 45 KTS IS EXPECTED TO BE MORE THAN
SUFFICIENT FOR SUPERCELLS INITIALLY...WITH 0-3 KM SRH VALUES WELL IN
EXCESS OF 200 M2/S2. THIS IS ESPECIALLY TRUE WHEN SHEAR VECTORS
ARE ORIENTED PERPENDICULAR TO THE FRONT AROUND 18Z. THE
CONVERGENCE ZONE EVENTUALLY BECOMES ORIENTED MORE SW-TO-NE BY
00Z...WHICH COULD HELP TRANSITION THINGS TO A LINEAR STORM MODE.
WOULD STILL EXPECT A FEW EMBEDDED SUPERCELLS IN SUCH AN
ENVIRONMENT. THE LATEST DAY 1 OUTLOOK FROM THE STORM PREDICTION
CENTER MAINTAINS AN ENHANCED RISK ACROSS MUCH OF THE PANHANDLE
INTO FAR EASTERN WYO. HRRR AND OTHER SIMULATED RADAR PRODUCTS SHOW
CONVECTION DEVELOPING OVER THE LARAMIE RANGE BY LATE MORNING OR
EARLY AFTERNOON...AND THEN MOVING EAST BEFORE MOVING OUT AROUND
03Z. UPDRAFT HELICITIES WOULD SUGGEST SUPERCELLS. VERY
LARGE/DAMAGING HAIL AND STRONG DOWNBURST WINDS SHOULD BE THE
PRIMARY HAZARD TODAY...BUT TORNADOES ARE ALWAYS POSSIBLE IN BACKED
LLVL FLOW REGIMES SUCH AS THESE. SOUNDINGS SHOW VERY LARGE/CURVED
HODOGRAPHS WITH 0-1 KM SHEAR OVER 20 KTS. NAM EHI VALUES ARE OVER
3...SO WOULD NOT BE SURPRISED TO SEE A FEW TORNADOES TODAY. OUR
MAIN CORRIDOR OF INTEREST WOULD BE FROM WHEATLAND/CHUGWATER
(ENHANCED CONVERGENCE WITH A MESOSCALE LOW) EASTWARD ACROSS THE
NEB PANHANDLE. VERY LOW LCLS ARE ALSO OMINOUS. ONE THING THAT
WOULD REALLY MESS UP OUR SEVERE POTENTIAL TODAY WOULD BE A LIKELY
MESSY STORM MODE. A LOT OF DIFFERENT FORCING MECHANISMS
TODAY...AND IT COULD BE DETRIMENTAL IF STORMS BECOME TOO
WIDESPREAD. THAT SAID...THE BUST POTENTIAL IS HIGH. THAT IS NOT TO
SAY WE WILL NOT NEED ALL HANDS ON DECK TODAY THOUGH.
A MUDDLED PATTERN WILL CONTINUE THROUGH THE REST OF THE WEEKEND WITH
DEEP TROUGHING OVER THE WESTERN CONUS. DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL EXIST WITH A VIRTUALLY UNLIMITED SUPPLY OF MIDLVL
DISTURBANCES ROUNDING THE BASE OF THE TROUGH. GFS 700 MILLIBAR TEMPS
AT OR BELOW -2 DEG C SUGGESTS POTENTIAL FOR ACCUMULATING SNOW OVER
THE MOUNTAINS...BUT THIS SHOULD BE SUB ADVISORY AT BEST AS DYNAMICS
DO NOT APPEAR TO BE ANYTHING TO WRITE HOME ABOUT. TEMPERATURES WILL
GENERALLY BE BELOW NORMAL WITH WIDESPREAD CLOUDS AND OCCASIONAL
PCPN.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 415 AM MDT FRI MAY 15 2015
RATHER COOL AND UNSETTLED EXTENDED PERIOD CONTINUES TO BE SHOWN BY
THE MODELS. MONDAY WILL LIKELY BE THE DRIEST DAY ACROSS THE REGION
WITH THE RIDGING ALOFT AND VERY LIMITED INSTABILITY (MAINLY OUT
WEST). THE BEST CHANCE OF SHOWERS WILL BE ALONG AND WEST OF THE
LARAMIE RANGE. SOUTHEASTERLY SFC WINDS WILL PUSH HIGHER DEWPOINTS
TOWARD THE LARAMIE RANGE BY TUES MORNING. AN UPPER LEVEL SYSTEM
OVER CALIFORNIA ON MON WITH MOVE QUICKLY NORTHEASTWARD ON TUES.
UPPER LEVEL DIVERGENCE AND DEEP LAYER ASCENT WILL INCREASE BY TUES
AFTN AND EVENING AND INTERACT WITH GOOD MOISTURE (PW VALUES ARE
ABOVE 0.75 INCHES) TO PRODUCE WIDESPREAD RAIN AND MAYBE AN
ISOLATED TSTM. LOOKING MORE LIKE A STRATIFORM EVENT...AND STRONG
STORMS WOULD NOT BE A CONCERN WITH THE GFS SHOWING REALLY NO CAPE
ACROSS THE PLAINS. WEAK SHORTWAVE WILL BE IN THE VICINITY OF
SOUTHWEST SOUTH DAKOTA ON WED WITH SCATTERED SHOWERS PERSISTING.
THERE IS SOME INDICATION THAT IT WILL DRY OUT BY THURS...HOWEVER
CAN NOT RULE OUT ISOLATED CONVECTION WITH LLVL UPSLOPE TO THE EAST
OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 549 AM MDT FRI MAY 15 2015
LOW CLOUDS AND IFR/MVFR CONDITIONS WILL PERSIST THROUGH THE MID
MORNING AT MANY OF THE PLAINS SITES. THE LOW CLOUDS WILL LIFT AND
BECOME MORE SCATTERED AFTER AROUND 16Z. GOOD MOISTURE AND
INSTABILITY WILL PROMOTE WIDESPREAD THUNDERSTORM DEVELOP BY EARLY
THIS AFTERNOON...ESPECIALLY TO THE EAST OF THE LARAMIE RANGE. SOME
OF THE STORMS COULD BE STRONG WITH GUSTY WINDS...HAIL...AND BRIEF
HEAVY RAIN. PREVAILING WINDS OUTSIDE OF THE STORMS WILL GENERALLY
BE FROM THE SOUTH TO SOUTHEAST.
&&
.FIRE WEATHER...
ISSUED AT 351 AM MDT FRI MAY 15 2015
MILD AND WET WEATHER PATTERN WILL CONTINUE OVER THE NEXT SEVERAL
DAYS. WETTING RAINS CAN BE EXPECTED FOR MANY AREAS. AS A RESULT...
FIRE WEATHER CONCERNS WILL BE MINIMAL WITH NON-CRITICAL CONDITIONS
LIKELY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
505 AM MDT FRI MAY 15 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT FRI MAY 15 2015
SHOWERS AND A FEW STRONG THUNDERSTORMS HAVE BEEN ONGOING FOR MUCH OF
THE NIGHT OVER THE PLAINS. THIS IS IN RESPONSE TO STRONG LLVL THETA-
E ADVECTION NORTH OF A STATIONARY BOUNDARY DRAPED FROM WEST TO EAST
ALONG THE I-80 CORRIDOR. BUFKIT SOUNDINGS FROM THE RAP MODEL SHOW UP
TO 500 J/KG OF MUCAPE TO THE NORTH OF THIS BOUNDARY...WHICH COMBINED
WITH MODEST DEEP LAYER VERTICAL SHEAR IS CONTRIBUTING TO SOME SMALL
HAIL PRODUCTION. ISSUED A FEW SPS PRODUCTS THIS MORNING TO HIGHLIGHT
THE STRONGEST CELLS...BUT EVERYTHING IS STAYING SUB-SEVERE. AIR MASS
ACROSS MUCH OF SOUTHEAST WYO/WESTERN NEB IS BECOMING VERY MOIST THIS
MORNING WITH LLVL EASTERLY/UPSLOPE FLOW. DEWPOINTS OVER WESTERN NEB
WERE ALREADY IN THE 50-55 F RANGE AT 10Z...AND THESE ARE EXPECTED TO
BE ADVECTED WESTWARD ALONG THE LARAMIE RANGE WITH TIME AS STRONG SFC
CYCLOGENESIS OVER EASTERN CO KEEPS NEAR-SFC FLOW BACKED OVER OUR CWA
THROUGH THE DAY. FORECAST SOUNDINGS AND THE OPERATIONAL HRRR SHOW AT
LEAST SOME POTENTIAL FOR FOG OVER THE PLAINS THROUGH 15Z. HOWEVER...
WIDESPREAD SHOWER ACTIVITY SHOULD KEEP THE BOUNDARY LAYER MIXED. WE
DECIDED TO REMOVE MENTION OF FOG FROM THE GRIDS AS ANY REDUCED VSBYS
WOULD BE QUITE ISOLATED.
ATTENTION THEN SHIFTS TO A MORE WIDESPREAD...POTENTIALLY SIGNIFICANT
SEVERE WEATHER EPISODE EVOLVING LATER TODAY. WE WILL REALLY NEED TO
WATCH THE POSITION OF THE SURFACE LOW TODAY AS LLVL WIND FIELDS WILL
PLAY A SIGNIFICANT ROLE IN CONVECTIVE MODE AND STORM INTENSITY. THE
GFS IS STILL AN APPARENT OUTLIER WITH 18-00Z POSITIONING OF A 995 MB
SURFACE LOW LIFTING OUT OF NORTHEAST CO. NOTHING UNUSUAL FOR THE GFS
AS THIS MODEL DOES HAVE A TENDENCY TO PUSH SURFACE FEATURES EASTWARD
TOO QUICKLY. THE NET RESULT IS THE DEVELOPMENT OF WESTERLY FLOW NEAR
THE SURFACE OVER MOST OF THE CWA BY AROUND 21Z. THE PREFERRED SOLNS
ARE STILL THE ECMWF AND NAM WITH THE SLOWER PROGRESSION...AND LONGER
RESIDENCE TIME OF EASTERLY FLOW EAST OF THE LARAMIE RANGE. THE BIG
QUESTIONS RIGHT NOW WILL BE ONGOING CONVECTION/LOW CLOUDS AND THEIR
OVERALL IMPACT ON INSTABILITY PARAMETERS. MORNING WATER VAPOR SHOWS
A MID LEVEL DRY SLOT MOVING INTO EASTERN CO...AND CLOUD TOPS ON THE
LATEST IR LOOP HAVE BEEN WARMING OVER THE LAST FEW HOURS. THUS...DO
NOT EXPECT PCPN TO BE A MAJOR INHIBITING FACTOR. STRONGLY DIFLUENT
FLOW ALOFT IS NOW DEVELOPING ACROSS THE CWA AHEAD OF A VIGOROUS LOW
OVER CA/NV...ALONG WITH A COUPLED H25 JET. MOST CONVECTION-ALLOWING
MODELS SHOW CIN ERODING ENTIRELY BY 18Z...SO STRONGLY BELIEVE THIS
WILL BE AN EARLY SHOW WITH TSTMS BECOMING WIDESPREAD BY AFTN. H7
TEMPS AROUND +7 DEG C OVER THE PANHANDLE WOULD SUGGEST CAPPING AND
LESS COVERAGE THERE. THE AFOREMENTIONED SURFACE BOUNDARY WILL LIFT
NORTHWARD AS A WARM FRONT LATER TODAY...SO THIS WILL SERVE AS THE
PRIMARY FOCUS FOR INITIATION AS WELL AS ENHANCED CONVERGENCE ALONG
THE LARAMIE RANGE.
ENVIRONMENTAL PARAMETERS CONTINUE TO SUGGEST INCREASING POTENTIAL
FOR DANGEROUS THUNDERSTORMS ALONG/EAST OF THE LARAMIE RANGE. GOOD
INSOLATION AND DEW POINTS IN THE MID 50S BENEATH VERY STEEP MID
LEVEL LAPSE RATES SHOULD YIELD SBCAPE OF 2000-3000 J/KG INVOF THE
WARM FRONT. 0 TO 6 KM SHEAR OVER 45 KTS IS EXPECTED TO BE MORE THAN
SUFFICIENT FOR SUPERCELLS INITIALLY...WITH 0-3 KM SRH VALUES WELL IN
EXCESS OF 200 M2/S2. THIS IS ESPECIALLY TRUE WHEN SHEAR VECTORS
ARE ORIENTED PERPENDICULAR TO THE FRONT AROUND 18Z. THE
CONVERGENCE ZONE EVENTUALLY BECOMES ORIENTED MORE SW-TO-NE BY
00Z...WHICH COULD HELP TRANSITION THINGS TO A LINEAR STORM MODE.
WOULD STILL EXPECT A FEW EMBEDDED SUPERCELLS IN SUCH AN
ENVIRONMENT. THE LATEST DAY 1 OUTLOOK FROM THE STORM PREDICTION
CENTER MAINTAINS AN ENHANCED RISK ACROSS MUCH OF THE PANHANDLE
INTO FAR EASTERN WYO. HRRR AND OTHER SIMULATED RADAR PRODUCTS SHOW
CONVECTION DEVELOPING OVER THE LARAMIE RANGE BY LATE MORNING OR
EARLY AFTERNOON...AND THEN MOVING EAST BEFORE MOVING OUT AROUND
03Z. UPDRAFT HELICITIES WOULD SUGGEST SUPERCELLS. VERY
LARGE/DAMAGING HAIL AND STRONG DOWNBURST WINDS SHOULD BE THE
PRIMARY HAZARD TODAY...BUT TORNADOES ARE ALWAYS POSSIBLE IN BACKED
LLVL FLOW REGIMES SUCH AS THESE. SOUNDINGS SHOW VERY LARGE/CURVED
HODOGRAPHS WITH 0-1 KM SHEAR OVER 20 KTS. NAM EHI VALUES ARE OVER
3...SO WOULD NOT BE SURPRISED TO SEE A FEW TORNADOES TODAY. OUR
MAIN CORRIDOR OF INTEREST WOULD BE FROM WHEATLAND/CHUGWATER
(ENHANCED CONVERGENCE WITH A MESOSCALE LOW) EASTWARD ACROSS THE
NEB PANHANDLE. VERY LOW LCLS ARE ALSO OMINOUS. ONE THING THAT
WOULD REALLY MESS UP OUR SEVERE POTENTIAL TODAY WOULD BE A LIKELY
MESSY STORM MODE. A LOT OF DIFFERENT FORCING MECHANISMS
TODAY...AND IT COULD BE DETRIMENTAL IF STORMS BECOME TOO
WIDESPREAD. THAT SAID...THE BUST POTENTIAL IS HIGH. THAT IS NOT TO
SAY WE WILL NOT NEED ALL HANDS ON DECK TODAY THOUGH.
A MUDDLED PATTERN WILL CONTINUE THROUGH THE REST OF THE WEEKEND WITH
DEEP TROUGHING OVER THE WESTERN CONUS. DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL EXIST WITH A VIRTUALLY UNLIMITED SUPPLY OF MIDLVL
DISTURBANCES ROUNDING THE BASE OF THE TROUGH. GFS 700 MILLIBAR TEMPS
AT OR BELOW -2 DEG C SUGGESTS POTENTIAL FOR ACCUMULATING SNOW OVER
THE MOUNTAINS...BUT THIS SHOULD BE SUB ADVISORY AT BEST AS DYNAMICS
DO NOT APPEAR TO BE ANYTHING TO WRITE HOME ABOUT. TEMPERATURES WILL
GENERALLY BE BELOW NORMAL WITH WIDESPREAD CLOUDS AND OCCASIONAL
PCPN.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 415 AM MDT FRI MAY 15 2015
RATHER COOL AND UNSETTLED EXTENDED PERIOD CONTINUES TO BE SHOWN BY
THE MODELS. MONDAY WILL LIKELY BE THE DRIEST DAY ACROSS THE REGION
WITH THE RIDGING ALOFT AND VERY LIMITED INSTABILITY (MAINLY OUT
WEST). THE BEST CHANCE OF SHOWERS WILL BE ALONG AND WEST OF THE
LARAMIE RANGE. SOUTHEASTERLY SFC WINDS WILL PUSH HIGHER DEWPOINTS
TOWARD THE LARAMIE RANGE BY TUES MORNING. AN UPPER LEVEL SYSTEM
OVER CALIFORNIA ON MON WITH MOVE QUICKLY NORTHEASTWARD ON TUES.
UPPER LEVEL DIVERGENCE AND DEEP LAYER ASCENT WILL INCREASE BY TUES
AFTN AND EVENING AND INTERACT WITH GOOD MOISTURE (PW VALUES ARE
ABOVE 0.75 INCHES) TO PRODUCE WIDESPREAD RAIN AND MAYBE AN
ISOLATED TSTM. LOOKING MORE LIKE A STRATIFORM EVENT...AND STRONG
STORMS WOULD NOT BE A CONCERN WITH THE GFS SHOWING REALLY NO CAPE
ACROSS THE PLAINS. WEAK SHORTWAVE WILL BE IN THE VICINITY OF
SOUTHWEST SOUTH DAKOTA ON WED WITH SCATTERED SHOWERS PERSISTING.
THERE IS SOME INDICATION THAT IT WILL DRY OUT BY THURS...HOWEVER
CAN NOT RULE OUT ISOLATED CONVECTION WITH LLVL UPSLOPE TO THE EAST
OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1146 PM MDT THU MAY 14 2015
WYOMING TAFS...SCATTERED SHOWERS DEVELOPING LATER TONIGHT. VFR
PREVAILS WITH PERIODS OF MVFR IN SHOWERS. IFR DEVELOPING THROUGH
THE PREDAWN HOURS AT LARAMIE AND CHEYENNE WITH LOW CLOUDS AND FOG
CONTINUING INTO MID MORNING. ISOLATED TO SCATTERED THUNDERSTORMS
DEVELOPING BY LATE MORNING FRIDAY AND CONTINUING IN THE AFTERNOON
WITH STORMS PRODUCING WIND GUSTS TO 35 KNOTS AND HAIL UP TO ONE
INCH IN DIAMETER. THUNDERSTORMS ENDING BY EARLY FRIDAY EVENING.
NEBRASKA TAFS...WIDESPREAD IFR DEVELOPING LATE THIS EVENING AND
OVERNIGHT WITH WIDESPREAD LOW CLOUDS AND FOG...ALONG WITH
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. AFTER DAYBREAK ON
FRIDAY...BECOMING MVFR IN THE MORNING WITH ISOLATED TO SCATTERED
THUNDERSTORMS DEVELOPING...AND INCREASING IN COVERAGE IN THE
AFTERNOON. ISOLATED TO SCATTERED THUNDERSTORMS WILL BECOME STRONG
TO SEVERE...WITH A FEW STORMS PRODUCING WIND GUSTS IN EXCESS OF 50
KNOTS AND WITH GS AND GR SIZE HAIL...AND A FEW SEVERE STORMS
PRODUCING HAILSTONES IN EXCESS OF ONE INCH IN
DIAMETER...ESPECIALLY NORTH OF A SCOTTSBLUFF TO ALLIANCE LINE.
THUNDERSTORMS ENDING IN THE EARLY EVENING WITH VFR PREVAILING.
&&
.FIRE WEATHER...
ISSUED AT 351 AM MDT FRI MAY 15 2015
MILD AND WET WEATHER PATTERN WILL CONTINUE OVER THE NEXT SEVERAL
DAYS. WETTING RAINS CAN BE EXPECTED FOR MANY AREAS. AS A RESULT...
FIRE WEATHER CONCERNS WILL BE MINIMAL WITH NON-CRITICAL CONDITIONS
LIKELY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...ZF
AVIATION...RUBIN
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
315 PM MST FRI MAY 15 2015
.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.
&&
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE THROUGH THE REGION THIS EVENING INTO
EARLY SATURDAY MORNING...RESULTING IN A CONTINUED PERIOD OF SHOWERS
AND ISOLATED THUNDERSTORMS ALONG WITH MUCH COOLER TEMPERATURES. A
GRADUAL WARMING TREND WILL COMMENCE THIS WEEKEND AS HIGH PRESSURE
SLOWLY BUILDS INTO THE AREA...BUT TEMPERATURES ARE FORECAST TO REMAIN
BELOW NORMAL VALUES FOR MID MAY. ANOTHER COOL BUT WEAKER PACIFIC
DISTURBANCE IS FORECAST ON MONDAY...WITH A SLIGHT CHANCE OF SHOWERS.
CLEARING SKIES WITH A WARMING TREND IS FORECAST NEXT TUESDAY THROUGH
FRIDAY.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO SLOWLY MOVE ONSHORE ACROSS
SOUTHERN CALIFORNIA...WITH THE BACK EDGE OF THE RAINFALL ALREADY
MOVING THROUGH THE INLAND EMPIRE. RAINFALL CONTINUES TO SPREAD
THROUGH SOUTHEAST CALIFORNIA INTO CENTRAL ARIZONA...WITH MOST
LOCATIONS IN THE FORECAST AREA SEEING AT LEAST A TRACE OF RAINFALL
THUS FAR. THE HIGHEST RAINFALL AMOUNTS THUS FAR HAVE BEEN IN AND
AROUND THE ANTHEM/CAVE CREEK/CAREFREE AREA /APPROX 0.43 INCHES AS OF
20Z/ DUE TO TRAINING THUNDERSTORMS EARLIER IN THE DAY.
IN THE VERY SHORT TERM /THROUGH THIS EVENING/...THE PAST SEVERAL
RUNS OF THE HRRR HAVE REMAINED REMARKABLY CONSISTENT IN SHOWING 2 OR
3 WAVES OF PRECIPITATION MOVING THROUGH THE LOWER AZ DESERTS...THE
FIRST OF WHICH SHOULD ARRIVE BY 21Z...ANOTHER AROUND 00Z...AND A
THIRD AROUND 06Z. REGIONAL RADAR AND WV SATELLITE IMAGERY SUGGESTS
THIS SOLUTION MAY ACTUALLY VERIFY AS ADVERTISED...AS THERE ARE
NUMEROUS CIRCULATIONS EVIDENT TO THE WEST OF PHOENIX. SINCE RAIN IS
ALREADY FALLING ACROSS MOST OF THE AREA AND IS EXPECTED TO CONTINUE
FOR THE NEXT SEVERAL HOURS...I WILL MAINTAIN 100 POPS ACROSS MOST OF
THE AREA. CONDITIONS WILL IMPROVE FROM WEST TO EAST THIS
EVENING...WITH RAINFALL WRAPPING UP FOR GOOD BEFORE MIDNIGHT ACROSS
SOUTHEAST CALIFORNIA. BUFR SOUNDINGS CONTINUE TO REVEAL A PERSISTENT
PERIOD OF 100-200 J/KG OF ELEVATED CAPE THIS EVENING AND OVERNIGHT
AND I WILL LEAVE THE MENTION OF THUNDER IN THE FORECAST ACCORDINGLY.
AS FOR QPF...EXPECTING A BROAD AREA OF QUARTER TO HALF INCH AMOUNTS
ACROSS THE DESERTS...WITH AMOUNTS APPROACHING THREE QUARTERS OF AN
INCH TO THE NORTH AND EAST OF PHOENIX.
&&
.PREVIOUS DISCUSSION...
A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL CONTINUE OVER THE
MOUNTAINS OF SOUTHERN GILA COUNTY THROUGH SATURDAY AFTERNOON.
SUNDAY...A BREAK IN THE WEATHER IS FORECAST WITH DRY AND CONTINUED
BELOW NORMAL TEMPERATURES AHEAD OF ANOTHER STRONG PACIFIC STORM
FORECAST FOR MONDAY.
MONDAY...ANOTHER UNSEASONABLY STRONG AND COLD PACIFIC STORM IS
FORECAST TO MOVE INTO THE REGION MONDAY...HOWEVER THIS SYSTEM WILL
NOT BE AS COLD...MOIST...NOR AS DYNAMICAL AS TODAYS/FRIDAY MAY 15TH
EVENT. NONE-THE-LESS...A SLIGHT CHANCE OF SHOWERS ARE FORECAST TO
SPREAD FROM WEST TO EAST...OR FROM SOUTHEAST CA MONDAY MORNING TO
SOUTH CENTRAL AZ BY AFTERNOON. 500/300 MB HEIGHT FALLS ARE FORECAST
TO BE MODERATELY STRONG ACROSS SOUTHWEST AND SOUTH CENTRAL AZ...OR
SIGNIFICANT ENOUGH NOT TO IGNORE THE SLIGHT PRECIP THREAT. CLEARING
SKIES MONDAY NIGHT EVERYWHERE.
TUESDAY...DRY SOUTHWESTERLY FLOW ALOFT IS FORECAST WITH OCCASIONAL
HIGH CLOUDS AND WARMER TEMPERATURES EACH DAY. THE WARMEST DAY WILL
BE THURSDAY...HOWEVER TEMPERATURES WILL STILL BE SLIGHTLY BELOW
NORMAL GENERALLY BY 5 DEGREES...I.E. LOWER 90S ON THE DESERTS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LOW PRESSURE SYSTEM MOVING THROUGH DESERT SOUTHWEST TODAY AND
SATURDAY. ANTICIPATE SCATTERED SHOWERS...AND A STRAY THUNDERSTORM...
THROUGH THE AFTERNOON WITH CIGS GENERALLY 6-8 KFT MSL...LOCALLY
5-7 KFT MSL AND VIS 5-6SM WITH STRONGER SHOWERS. ANTICIPATE MORE
WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS AFT 02Z AND CIGS 3-5
KFT MSL BEFORE SHOWERS BEGIN TO IMPROVE 08Z. WIND DIRECTIONS WILL BE
ERRATIC FAVORING WESTERLY DIRECTIONS. GUSTS OF 20-25 KTS WILL BE
COMMON UNTIL ABOUT 06Z.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SCATTERED TO NUMEROUS SHOWERS...AND POSSIBLY A STRAY
THUNDERSTORM...WILL CONTINUE THROUGH THE DAYLIGHT HOURS BEFORE
TAPERING OFF AFTER 03Z. ANTICIPATE CIGS 6-8 KFT MSL...LOCALLY 4-6
KFT MSL. WIND DIRECTIONS WILL BE ERRATIC BUT FAVOR NORTHERLY
COMPONENTS. SUSTAINED SPEEDS WILL BE LESS THAN 10 KTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
A COUPLE OF FOLLOW-ON SYSTEMS WILL MOVE THROUGH THE DESERT SOUTHWEST
DURING THE NEXT WORK WEEK. THIS WILL KEEP TEMPERATURES BELOW NORMAL
AND THERE WILL BE BREEZY CONDITIONS AT TIMES. THESE SYSTEMS ARE NOT
EXPECTED TO BE AS MOIST AS THE PRECEDING SYSTEM AND THUS MINIMUM
HUMIDITIES WILL GENERALLY BE IN THE 10-15 PERCENT RANGE ON THE
LOWER ELEVATIONS. HOWEVER...NO CRITICAL CONDITIONS ARE EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
221 PM MST FRI MAY 15 2015
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE THROUGH THE REGION THIS EVENING INTO
EARLY SATURDAY MORNING...RESULTING IN A CONTINUED PERIOD OF SHOWERS
AND ISOLATED THUNDERSTORMS ALONG WITH MUCH COOLER TEMPERATURES. A
GRADUAL WARMING TREND WILL COMMENCE THIS WEEKEND AS HIGH PRESSURE
SLOWLY BUILDS INTO THE AREA...BUT TEMPERATURES ARE FORECAST TO REMAIN
BELOW NORMAL VALUES FOR MID MAY. ANOTHER COOL BUT WEAKER PACIFIC
DISTURBANCE IS FORECAST ON MONDAY...WITH A SLIGHT CHANCE OF SHOWERS.
CLEARING SKIES WITH A WARMING TREND IS FORECAST NEXT TUESDAY THROUGH
FRIDAY.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO SLOWLY MOVE ONSHORE ACROSS
SOUTHERN CALIFORNIA...WITH THE BACK EDGE OF THE RAINFALL ALREADY
MOVING THROUGH THE INLAND EMPIRE. RAINFALL CONTINUES TO SPREAD
THROUGH SOUTHEAST CALIFORNIA INTO CENTRAL ARIZONA...WITH MOST
LOCATIONS IN THE FORECAST AREA SEEING AT LEAST A TRACE OF RAINFALL
THUS FAR. THE HIGHEST RAINFALL AMOUNTS THUS FAR HAVE BEEN IN AND
AROUND THE ANTHEM/CAVE CREEK/CAREFREE AREA /APPROX 0.43 INCHES AS OF
20Z/ DUE TO TRAINING THUNDERSTORMS EARLIER IN THE DAY.
IN THE VERY SHORT TERM /THROUGH THIS EVENING/...THE PAST SEVERAL
RUNS OF THE HRRR HAVE REMAINED REMARKABLY CONSISTENT IN SHOWING 2 OR
3 WAVES OF PRECIPITATION MOVING THROUGH THE LOWER AZ DESERTS...THE
FIRST OF WHICH SHOULD ARRIVE BY 21Z...ANOTHER AROUND 00Z...AND A
THIRD AROUND 06Z. REGIONAL RADAR AND WV SATELLITE IMAGERY SUGGESTS
THIS SOLUTION MAY ACTUALLY VERIFY AS ADVERTISED...AS THERE ARE
NUMEROUS CIRCULATIONS EVIDENT TO THE WEST OF PHOENIX. SINCE RAIN IS
ALREADY FALLING ACROSS MOST OF THE AREA AND IS EXPECTED TO CONTINUE
FOR THE NEXT SEVERAL HOURS...I WILL MAINTAIN 100 POPS ACROSS MOST OF
THE AREA. CONDITIONS WILL IMPROVE FROM WEST TO EAST THIS
EVENING...WITH RAINFALL WRAPPING UP FOR GOOD BEFORE MIDNIGHT ACROSS
SOUTHEAST CALIFORNIA. BUFR SOUNDINGS CONTINUE TO REVEAL A PERSISTENT
PERIOD OF 100-200 J/KG OF ELEVATED CAPE THIS EVENING AND OVERNIGHT
AND I WILL LEAVE THE MENTION OF THUNDER IN THE FORECAST ACCORDINGLY.
AS FOR QPF...EXPECTING A BROAD AREA OF QUARTER TO HALF INCH AMOUNTS
ACROSS THE DESERTS...WITH AMOUNTS APPROACHING THREE QUARTERS OF AN
INCH TO THE NORTH AND EAST OF PHOENIX.
&&
.PREVIOUS DISCUSSION...
A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL CONTINUE OVER THE
MOUNTAINS OF SOUTHERN GILA COUNTY THROUGH SATURDAY AFTERNOON.
SUNDAY...A BREAK IN THE WEATHER IS FORECAST WITH DRY AND CONTINUED
BELOW NORMAL TEMPERATURES AHEAD OF ANOTHER STRONG PACIFIC STORM
FORECAST FOR MONDAY.
MONDAY...ANOTHER UNSEASONABLY STRONG AND COLD PACIFIC STORM IS
FORECAST TO MOVE INTO THE REGION MONDAY...HOWEVER THIS SYSTEM WILL
NOT BE AS COLD...MOIST...NOR AS DYNAMICAL AS TODAYS/FRIDAY MAY 15TH
EVENT. NONE-THE-LESS...A SLIGHT CHANCE OF SHOWERS ARE FORECAST TO
SPREAD FROM WEST TO EAST...OR FROM SOUTHEAST CA MONDAY MORNING TO
SOUTH CENTRAL AZ BY AFTERNOON. 500/300 MB HEIGHT FALLS ARE FORECAST
TO BE MODERATELY STRONG ACROSS SOUTHWEST AND SOUTH CENTRAL AZ...OR
SIGNIFICANT ENOUGH NOT TO IGNORE THE SLIGHT PRECIP THREAT. CLEARING
SKIES MONDAY NIGHT EVERYWHERE.
TUESDAY...DRY SOUTHWESTERLY FLOW ALOFT IS FORECAST WITH OCCASIONAL
HIGH CLOUDS AND WARMER TEMPERATURES EACH DAY. THE WARMEST DAY WILL
BE THURSDAY...HOWEVER TEMPERATURES WILL STILL BE SLIGHTLY BELOW
NORMAL GENERALLY BY 5 DEGREES...I.E. LOWER 90S ON THE DESERTS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LARGE AND STRONG AREA OF PACIFIC LOW PRESSURE WILL MOVE INTO THE
AREA TODAY...FILLING IN MID-LEVEL CIGS AND MAINTAINING SOME WESTERLY
COMPONENT TO WINDS THROUGH THE DAY. SPEEDS WILL BE UNDER THOSE
OBSERVED ON THURSDAY WITH GUSTS INTO THE UPPER TEENS. VCSH ACTIVITY
WILL CONTINUE TO PERCOLATE ACROSS SOUTH-CENTRAL AZ INTO THE
AFTERNOON BEFORE BECOMING MORE WIDESPREAD AND PERSISTENT IN NATURE.
THE PERIOD OF STEADY RAINFALL...AND POTENTIAL FOR AT LEAST VCTS...IS
PROGGED FOR EARLY EVE THROUGH AROUND MIDNIGHT LOCAL. BKN TO OVC CIGS
EXPECTED TO FALL AOB 5K FEET DURING THE RAIN EVENT...WITH SCT CLOUD
LAYERS AS LOW AS 2-3 K FEET...AND VISIBILITIES FALLING INTO THE 3-5
MILE RANGE. WIND HEADINGS DURING THE ONSET OF THE HEAVIER RAINFALL
ARE A LITTLE TRICKIER TO CAPTURE... BKN-OVC CIGS ARE
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ON AND OFF RAIN SHOWER ACTIVITY WILL CONTINUE THROUGH MUCH OF THE
DAY AS AN AREA OF STRONG PACIFIC LOW AND ITS ASSOCIATED COLD FRONT
MOVE THROUGH THE AREA. WESTERLY WINDS TO PERSIST FOR KIPL WITH
SPEEDS GNLY 10-15KTS AND SOUTHERLY WINDS FOR KBLH WITH SIMILAR
SPEEDS.SHOWERS WILL LIKELY PUSH CIGS DOWN INTO THE 3-5K FEET RANGE
BEFORE GRADUALLY CLEARING/THINNING FRIDAY EVENING/OVERNIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
FAIRLY ACTIVE STORM PATTERN WILL STAY OVER THE WEST AND DIP BACK
THROUGH THE SOUTHWEST STATES THROUGH THE WEEK. IN THE WAKE OF
SATURDAY`S STORM... DRIER CONDITIONS WILL OVERSPREAD THE REGION
SUNDAY. ANOTHER STORM SYSTEM WILL EXPAND INTO THE GREAT BASIN BY THE
MIDDLE OF THE WEEK...AND WHILE LITTLE TO NO PRECIPITATION WILL
ACCOMPANY THIS STORM...MOISTURE LEVELS WILL REMAIN UNSEASONABLY
HIGH. AFTERNOON HUMIDITY LEVELS WILL ONLY FALL INTO A 15 TO 25
PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY AS TEMPERATURES HOVER
SLIGHTLY BELOW NORMAL. WIND SPEEDS DO NOT LOOK UNUSUALLY
STRONGER...WITH JUST THE TYPICAL AFTERNOON UPSLOPE GUSTINESS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS EUREKA CA
343 PM PDT FRI MAY 15 2015
.SYNOPSIS...A SERIES OF UPPER LOW PRESSURE SYSTEMS WILL BRING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO MAINLY THE
INTERIOR EACH AFTERNOON AND EVENING THROUGH MID NEXT WEEK.
OTHERWISE MOSTLY DRY WEATHER WITH BELOW NORMAL TEMPERATURES
WILL CONTINUE TO PREVAIL.
&&
.DISCUSSION...A BROAD AND COMPLEX UPPER LEVEL OVER THE GREAT
BASIN WILL CONTINUE TO SLOWLY TRACK EASTWARD AWAY FROM NORTHWEST
CALIFORNIA TONIGHT. WRAP AROUND MOISTURE AND PRECIP HAS BEEN
IMPACTING MAINLY SISKIYOU AND MODOC COUNTIES TODAY WITH ABUNDANT
CLOUD COVER AND SHOWERS. A FEW SPOTTY SHOWERS WERE SPILLING OVER
INTO MAINLY THE HIGHER ELEVATIONS OF ZONES 3 AND 4 THIS AFTERNOON.
THE ONSHORE NW FLOW IN THE LOWER LEVELS OF THE ATMOSPHERE HAS
CREATED MORE STABILITY TODAY AND NO LIGHTENING ACTIVITY IS
ANTICIPATED THIS EVENING.
A WEAK UPPER RIDGE WILL BUILD OVER THE AREA LATER TONIGHT INTO
SAT MORNING. THIS SHOULD CREATE STABILITY WITH VERY MINIMAL SHOWER
CHANCES OVER THE HIGHER TERRAIN. ANOTHER UPPER LOW WILL DIG
TOWARD THE NORTH COAST SAT AFTERNOON AND EVENING. WEAK
INSTABILITY WITH LONG THIN CAPE WILL PERSIST ACROSS THE EASTERN
PORTION OF THE AREA ON SAT AND A FEW LATE DAY SHOWERS ARE
EXPECTED OVER THE HIGHER TERRAIN. BUFKIT PROFILES SHOW A STABLE
LAYER ALOFT...SO CONFIDENCE WE WILL GET SUFFICIENT BOUNDARY LAYER
HEATING TO OVERCOME THE CIN FOR STORMS OVER THE TRINITY HORN AND
THE YOLLA BOLLYS IS NOT VERY HIGH.
SUNDAY IS STILL LOOKING LIKE THE BEST DAY FOR MORE INTERIOR
CONVECTION AS THE UPPER LOW APPROACHES CAPE MENDO AND THEN SLOLWY
MEANDERS SOUTHWARD THROUGH MONDAY MORNING. THE AXIS OF GREATEST
INSTABILITY AND PRECIP SHOULD SHIFT WESTWARD INTO WESTERN PORTIONS
OF HUMBOLDT AND DEL NORTE COUNTIES WITH PERHAPS SOME ACTIVITY IN
FAR NORTHERN MENDOCINO BY SUNDAY NIGHT. CONFIDENCE THUNDERSTORMS
WILL ADVECT OUT TO THE COAST IS NOT HIGH DUE TO THE LOW CAPE
VALUES AND FAIRLY LOW EQUILIBRIUM LEVELS. THE STORMS WILL SPROUT UP
WITH HEATING OVER THE MOUNTAINS THEN QUICKLY COLLAPSE...SIMILAR TO
THE STORMS YESTERDAY. THE GFS HAS BEEN A BIT TOO BROAD BRUSH WITH
THE CONVECTIVE PRECIP SO WILL CONTINUE TO USE THE NAM12 AS THE
PRIMARY GUIDANCE. THE HIRES-NMM AND HRRR HAVE BEEN MODELING THE
CONVECTION FAIRLY GOOOD AS WELL. THUS THE BROAD BRUSH GFS FIELDS
HAVE BEEN SCALED BACK. SHOWER CHANCES AND ISOLATED STORMS WILL
LIKELY PERSIST INTO MONDAY.
.LONG-TERM...TUE THROUGH FRI...NORTHWEST CALIFORNIA WILL REMAIN
WITHIN A LONG WAVE TROUGH PATTERN THROUGH MID-WEEK. ANOTHER
COMPLEX AND CONVOLUTED UPPER LOW WILL APPROACH ON TUE AND PRODUCE
INSTABILITY FOR AFTERNOON AND EVENING SHOWERS WITH ISOLATED TSTMS
PRIMARILY OVER THE INTERIOR THROUGH THU. THE GFS AND ECMWF
INDICATE SELY AND ELY FLOW ALOFT WHICH MAY SERVE TO PUSH A FEW
SHOWERS OUT TO THE COAST. THE CORE OF THE LOW ALOFT WILL PROBABLY
SWING SOUTHWARD TOWARD CENTRAL AND SOUTHERN CALIFORNIA ON FRI AND
THEN INTO THE GREAT BASIN/DESERT SW BY SAT PUTTING NW CALIFORNIA
IN DRIER AND MORE STABLE AIR AS A RIDGE ALOFT BUILDS TOWARD THE
COAST. THE ECMWF AND GEM WERE THE MOST AGGRESSIVE WITH BUILDING
THE RIDGE...WHILE THE GFS BRINGS ANOTHER UPPER LOW DOWN THE WEST
COAST IN THE NORTHERLY FLOW. FOR FRI...WILL MENTION ONLY A SLIGHT
CHANCE OF SHOWERS IN TRINITY COUNTY IN THE OUTSIDE CHANCE THE GFS
IS CORRECT.
&&
.AVIATION...SKIES ARE GENERALLY CLEAR ALONG THE IMMEDIATE COAST
HOWEVER SOME BUILD UP OF STRATO CU IS FORMING ON THE COASTAL HILLS.
AT THIS TIME COASTAL AIR TERMINALS ARE MAINLY VFR BUT CEC IS SHIFTING
FROM MVFR TO VFR AND THAT SHOULD CONTINUE THROUGH THE REMAINDER OF
THE AFTERNOON. CLOUDS AND LOW CEILINGS WILL LIKELY RETURN ALONG THE
COAST LATER TONIGHT. INTERIOR SITES SHOULD REMAIN VFR BUT KUKI MAY
BUT MAY SEE SOME FOG AND LOW CLOUDS AGAIN LATE TONIGHT BUT CHANCES
ARE LESS DUE TO SOME DRYING TODAY.
&&
.MARINE...THIS AFTERNOON WIND AND SEAS ARE TAME AND REMAINING BELOW
SCA THRESHOLDS HOWEVER SHORTER PERIOD WIND WAVES WILL BUILD A LITTLE
THIS EVENING. A SMALL SOUTHERLY SWELL IS ALSO PRESENT IN THE
WATERS...BUT WILL LIKELY DECAY THROUGH THE WEEKEND AND IS NOT
EXPECTED TO HAVE MAJOR IMPACTS. BEYOND THIS EVENING AND THROUGH THE
MIDDLE OF THE WEEK...NORTHERLY WINDS WILL REMAIN NEAR OR SLIGHTLY
BELOW SMALL CRAFT ADVISORY LEVEL...WHILE ANOTHER REINFORCING
WESTERLY SWELL WILL PROPAGATE THROUGH THE WATERS.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA
FOLLOW US ON FACEBOOK AND TWITTER AT:
HTTP://WWW.FACEBOOK.COM/NWSEUREKA
HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1104 AM MDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1039 AM MDT FRI MAY 15 2015
CONVECTION HAS STARTED ALREADY OVER THE MOUNTAINS...FOOTHILLS AND
PALMER RIDGE. THERE ARE A FEW BOUNDARIES FLOATING AROUND THE
PLAINS RIGHT NOW. THE MAIN ONE IS ALONG THE SOUTHERN CWA BORDER THEN
IT IS ORIENTED SOUTHWEST/NORTHEAST UP THROUGH ELBERT COUNTY INTO
EAST ARAPAHOE AND ADAMS. THE SOUTH-SOUTHEASTERLIES WINDS SOUTH OF
IT ARE COMING OFF THE HIGHER TERRAIN AND THE DOWNSLOPING HAS DRIED
OUT DEW POINTS INTO THE 30S F. MOST OF THE PLAINS OF THE CWA HAVE
DEW POINTS IN THE MID 40S TO LOWER 50S F RIGHT NOW. THAT BOUNDARY
IS MOVING NORTHWARD SLOWLY BUT SHOULD PROVIDE THE IMPETUS FOR
THUNDERSTORMS TO DEVELOP AT SOME POINT IN THE NEXT COUPLE OF
HOURS. WILL MAKE SOME ADJUSTMENTS TO POPS AND CLOUD COVER...BUT
NOTHING MAJOR.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 459 AM MDT FRI MAY 15 2015
COMPLEX SITUATION TODAY AS SOUTHERLY FLOW STRENGTHENS AHEAD OF
THE UPPER LOW OVER SOUTHERN NEVADA. BIGGEST QUESTION IS THE
POSITION OF LOW LEVEL FEATURES ON THE PLAINS THIS AFTERNOON AND
THE AMOUNT OF HEAT AND MOISTURE AVAILABLE FOR CONVECTION. SEVERAL
FACTORS ARE FAVORABLE FOR SEVERE WEATHER...MOST NOTABLY STRONG
SHEAR AND A PLUME OF MOISTURE PUSHING WESTWARD ON THE NORTH SIDE
OF A SURFACE LOW/TROUGH THAT WILL BE IN EASTERN COLORADO. IT IS
ALSO LOOKING LIKE THERE WILL BE ENOUGH DRY MID LEVEL AIR TO ALLOW
A FAIR AMOUNT OF SUN OVER NORTHEAST COLORADO TODAY...WHILE THE
WESTWARD EXTENT OF THE GOOD MOISTURE MAY BE A BIT MORE THAN
PREVIOUSLY EXPECTED. ALWAYS HARD TO SECOND GUESS JUST HOW MUCH
MIXING OUT OF THE MOISTURE THERE WILL BE...CERTAINLY WEST OF THE
DRY LINE THIS WILL HAPPEN...BUT ON THE NORTH SIDE OF THE LOW THE
PLUME OF MOISTURE WRAPPING AROUND WILL NOT MIX AS MUCH. BIGGEST
QUESTION IS PROBABLY THE SHARPNESS OF THE LOW/TROUGH FEATURE WHICH
IS OFTEN UNDERDONE IN THE MODELS. AT THIS HOUR THE HRRR IS SHOWING
A PLUME OF EAST WINDS HOLDING 50 DEGREE DEW POINTS AND CAPES
AROUND 2000 J/KG ALONG THE NORTHERN BORDER BACK AS FAR AS WELD
COUNTY. HOWEVER IT ALSO SCOURS OUT THE MOISTURE IN AREAS FURTHER
SOUTH...DRYING OUT WASHINGTON COUNTY BY MID AFTERNOON BEFORE THE
CONVECTION GETS GOING.
A NEGATIVE FACTOR MAY BE TOO MUCH SOUTHERLY WIND. THIS MAY HELP
DRY THINGS OUT AND PUSH THE BETTER MOISTURE TO THE NORTH...AND MAY
ALSO REDUCE THE SHEAR AND ESPECIALLY THE HELICITY IF THE WIND
PROFILE WINDS UP BEING PRETTY LINEAR. THERE SHOULD BE A SWEET SPOT
WITH THE LOW LEVEL WINDS BACKED TO EASTERLY...MOST LIKELY NEAR OUR
NORTHERN BORDER OR JUST INTO NEBRASKA. THIS AREA WOULD HAVE THE
BEST THREAT OF SEVERE WEATHER AND A DECENT TORNADO THREAT. WILL GO
WITH THIS IDEA AS THE MOST LIKELY SCENARIO...WITH STRONG STORMS
DEVELOPING IN THE MOISTURE ALONG THE DRY LINE AND/OR NORTH OF THE
LOW/TROUGH WHERE CAPES WILL BE 1500-2000 J/KG...THEN PROPAGATING
NORTH WITH THE SEVERE THREAT INCREASING NEAR OUR NORTHERN BORDER.
OTHER STORMS WILL FORM ON THE BACK EDGE OF THE DRY SLOT...NEAR THE
FRONT RANGE/CHEYENNE RIDGE BUT SHOULD BE WEAKER WITH CAPES OF 500
J/KG NEAR THE MOUNTAINS AND IMPROVING A BIT AS THEY MOVE EAST INTO
THE MOISTURE TONGUE. STILL COULD BE SOME SEVERE THREAT HERE AS
WELL...MAINLY IN NORTHERN WELD COUNTY. OF COURSE IF THE LOW WINDS
UP BEING BETTER DEFINED THERE WOULD BE A MUCH HIGHER THREAT OF
SEVERE WEATHER ON THE NORTH AND NORTHEAST SIDE OF THE LOW.
RAISED HIGHS A LITTLE EXPECTING MORE SUN...STILL A FEW DEGREES
BELOW GUIDANCE AND IF IT IS A LITTLE WARMER THAT WILL HELP AS
WELL. TRENDED POPS MORE TOWARD THE IDEA OF A GOOD BREAK IN THE DRY
SLOT MUCH OF TODAY...WITH STORMS MOVING IN FROM THE WEST AND
DEVELOPING IN THE NORTH AND EAST IN THE LATE AFTERNOON. BEST
COVERAGE PROBABLY IN THE EARLY EVENING ON THE PLAINS...BUT
INTESITY SHOULD BE LESS THEN. SOME CLOUDS AND WEAK SHOWERS HANG ON
OVERNIGHT WITH A LITTLE COOLING ALOFT AND OVERALL INCREASE IN
MOISTURE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM MDT FRI MAY 15 2015
OVERALL TREND IN THE FORECAST IS THE SAME. THE NEXT SYSTEM WILL
IMPACT THE CWA ON SATURDAY. THE BROAD BUT CLOSED UPPER TROUGH WILL
STRETCH FROM THE NORTHERN ROCKIES TO THE DESERT SOUTHWEST AT 12Z
SATURDAY...WITH A MODERATE TO STRONG SLY FLOW OVER EASTERN
COLORADO. WEAK TO MODERATE MID AND UPPER LEVEL QG ASCENT WILL
REMAIN OVER NORTHEAST COLORADO THROUGH THE DAY...WITH PLENTY OF
MOISTURE IN PLACE. MAIN ISSUE WILL BE WHERE THE SFC LOW SETS UP
AND AT THIS TIME IT APPEARS TO BE ALONG THE EASTERN BORDER. IF
THIS OCCURS...THEN THE STRONG/SEVERE THUNDERSTORMS WILL LIKELY BE
EAST OF COLORADO...BUT CANNOT RULE OUT ONE OR TWO REACHING SEVERE
LEVELS ALONG THE BORDER WHERE THE BEST VERTICAL SHEAR WILL BE
PRESENT. IN AND AROUND DENVER FORECAST CAPES IN THE AFTERNOON NOT
BAD...800-900 J/KG. MOISTURE AOA 700 MB IN THE AFTN...BUT DRIER IN
THE LOWER LEVELS. IN THE MOUNTAINS...NO HIGHLIGHTS BUT COULD SEE
UP TO 5 INCHES ABOVE 10 KT THROUGH THE DAY SATURDAY.
SATURDAY NIGHT INTO SUNDAY...THE QG ASCENT SHIFTS TO THE NORTH AND
EAST WITH INCREASING QG DESCENT OVER THE REGION. THE MID LEVEL
TROUGH AXIS SLIDES EASTWARD SATURDAY EVENING...WITH SUBSIDENCE
IN PLACE AS A SHORT WAVE RIDGE PUSHES INTO THE STATE THROUGH
SUNDAY. SOME LINGERING SHOWERS IN THE HIGH COUNTRY WEST OF THE
CONTINENTAL DIVIDE...BUT DOWNSLOPE IN AND NEAR THE FRONT RANGE
FOOTHILLS SHOULD NEGATE MUCH OF THE PCPN IN THE 03Z-06Z WINDOW.
FOR SUNDAY AFTERNOON...SHOWERS AND A FEW STORMS ARE PROGGED TO
DEVELOP AS MID LEVEL MOISTURE AND AFTN HEATING WILL OFFSET THE
INFLUENCE OF THE RIDGE.
SUNDAY NIGHT...A SURFACE HIGH IS PROGGED TO PUSH A COLD FRONT INTO
THE FRONT RANGE IN THE EVENING. LINGERING SHOWERS AND ISOLATED
THUNDERSTORMS WILL LINGER THROUGH SUNDAY EVENING. NOT MUCH IN THE
WAY OF PCPN FM 06Z-18Z MONDAY. THE UPPER RIDGE WILL SHIFT TO THE
EAST WITH THE FLOW ALOFT BECOMING SOUTHWESTERLY AHEAD OF THE NEXT
DEVELOPING TROUGH. MUCH OF THE SHOWER/TSTM ACTIVITY ON MONDAY
AFTN WILL OCCUR IN THE HIGH COUNTRY. MDLS STILL PEG ANOTHER GOOD
CHC OF PCPN FOR MUCH OF THE CWA LATE MONDAY NIGHT THROUGH TUESDAY
EVENING. A MOIST SOUTHERLY FLOW ALOFT AHEAD OF THIS TROUGH...
OVERRUNNING AND STATIONARY FRONTAL BOUNDARY SITTING ALONG THE
FRONT RANGE/PALMER DIVIDE. THIS BROAD TROUGH IS PROGGED TO LIFT
NORTHWARD TUESDAY NIGHT...BUT NOT ENOUGH TO DRY THE REGION OUT ON
WEDNESDAY/THURSDAY. BEST CHC OF SHOWERS/TSTMS THOSE DAYS APPEAR TO
BE FROM THE FRONT RANGE EASTWARD WHERE THE BEST MOISTURE WILL BE.
OVERALL TEMPERATURES WL REMAIN COOLER THAN NORMAL...COLDEST ON
SATURDAY AND THEN TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z SATURDAY MORNING)
ISSUED AT 1039 AM MDT FRI MAY 15 2015
AS MENTIONED ABOVE...THERE ARE A NUMBER OF BOUNDARIES FLOATING
AROUND WHICH WILL PLAY HAVOC WITH THE DIA WIND DIRECTIONS. THERE
IS A BOUNDARY WELL SOUTH OF DIA...STILL A FEW HOURS OUT OF BRING
SOUTHEASTERLIES TO THE AIRPORT. THERE IS CONVECTION STARTING IN
CENTRAL DOUGLAS COUNTY RIGHT WHICH MAY ACCELERATE THE ARRIVAL OF
THE SOUTHERLIES OR SOUTHEASTERLIES. WILL LEAVE THE NORTH-
NORTHWESTERLIES IN FOR NOW. WILL GO WITH A TEMPO FOR TSRA AFTER
19Z-20Z. NO CEILING ISSUES.
&&
.HYDROLOGY...
ISSUED AT 1039 AM MDT FRI MAY 15 2015
RIVER LEVELS ON THE SOUTH PLATTE WILL CONTINUE TO SLOWLY
RECEDE WITH THE EXCEPTION OF ITS COURSE THROUGH SEDGWICK. IT IS
STILL EXPECTED TO RISE IN SEDGWICK COUNTY INTO MID DAY SATURDAY
WITH THE CREST AT JULESBURG FORECAST TO BE BELOW FLOOD STAGE. IT
SHOULD START TO RECEDE AT JULESBURG BY SATURDAY AFTERNOON.
THE CACHE LA POUDRE RIVER IN WELD COUNTY IS JUST ABOVE FLOOD
STAGE AND THIS WILL CONTINUE INTO SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RJK
SHORT TERM...GIMMESTAD
LONG TERM...COOPER
AVIATION...RJK
HYDROLOGY...RJK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
659 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT MAY BRING A PERIOD OF RAIN TONIGHT INTO SATURDAY
MORNING AS THE FRONT MOVES ACROSS THE REGION. WARM AND MORE HUMID
WEATHER FOLLOWS SAT NIGHT INTO SUNDAY. THEN A BACKDOOR COLD FRONT
USHERS IN MUCH COOLER AIR INTO THE REGION SUNDAY NIGHT THROUGH EARLY
NEXT WEEK. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS TO THE
REGION MON NIGHT INTO TUE FOLLOWED BY DRY WEATHER MID TO LATE NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
7 PM UPDATE...
TWO SMALL VORTICES...ONE OVER THE CATSKILLS AND A SLIGHTLY MORE
VIGOROUS VORTEX ENTERING LAKE ONTARIO IS TRIGGERING SOME SHOWERS
ACROSS NY STATE. MUCH OF THIS ACTIVITY IS STRUGGLING TO REACH THE
GROUND GIVEN 20-30 DEG DEW PT DEPRESSIONS. THUS INITIALLY THIS
RAIN WILL DRY UP BEFORE REACHING SOUTHERN NEW ENGLAND. LATEST HRRR
AND RAP KEEP OUR AREA DRY THRU 03Z AND THEN SHOWERS ARRIVING
THEREAFTER FROM WEST TO EAST. PREVIOUS FORECAST CAPTURES THESE
DETAILS NICELY SO LITTLE IF ANY CHANGES WITH THIS UPDATE. EARLIER
DISCUSSION BELOW.
====================================================================
INTO THIS EVENING...
SCATTERED TO BROKEN CLOUD DECKS AS WE BEGIN TO COOL OFF TOWARDS
THE OVERNIGHT HOURS. SOUTHERLY FLOW CONTINUING AHEAD OF THE
APPROACHING WARM FRONT PRESENTLY ACROSS E NY AND CENTRAL PA. SEA-
BREEZES CONTINUING ALONG THE E-SHORE.
TONIGHT...
INITIAL INFLUX OF WARM-MOIST AIR UNDERGOING ISENTROPIC ASCENT WHILE
BEING FED REARWARD BY A NOTCH OF ENHANCED LOW-LEVEL FLOW VEERING
INTO N NEW ENGLAND. ITS ALONG THE NOSE OF WHICH...THE LEADING EDGE
BEING A LOW- TO MID-LEVEL WARM FRONT...THERE WILL BE THE FOCUS FOR
SHOWER ACTIVITY.
CONFIDENT OF ACTIVITY ACROSS THE W-HALF OF NEW ENGLAND JUST BASED ON
A CONSENSUS OF TIMING OF THE DEEP-LAYER MOIST PROFILE UNDERGOING LOW-
TO MID-LEVEL FORCING. E-HALF SHOULD REMAIN FOR THE MOST PART DRY ESP
WITHIN THE I-95 CORRIDOR / I-495 BELTWAY. ACTIVITY PUSHING WITH THE
MEAN-FLOW AROUND THE RIDGE IN PLACE. NOT ANTICIPATING ANY THUNDER.
EXPECTING LIGHT ACTIVITY WITH LACK OF DEEP-LAYER FORCING.
MILD CONDITIONS OVERNIGHT WITH LOWS AROUND THE UPPER-40S TO LOW-50S.
AM EXPECTING IT TO BE SLIGHTLY COOLER TO THE E.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SATURDAY...
LOOKING AT THE BIGGER PICTURE AND EVALUATING THE ENVIRONMENT: BEHIND
THE WARM-FRONT EXPECTING A PERIOD OF DRY AIR AND SUBSIDENCE ALLOWING
CLOUDS TO BECOME SCATTERED-BROKEN ACROSS S NEW ENGLAND. RETURN S/SW-
FLOW PUSHES THE BETTER AXES OF MOISTURE AND INSTABILITY INTO PA AND
UPSTATE NY. RIDGE ENHANCES IN RESPONSE TO INCREASING ANTI-CYCLONIC
FLOW OF THE WARM CONVEYOR BELT BETWEEN THE CENTRAL CONUS LOW AND
BERMUDA HIGH NETTING A SURFACE REFLECTION OF HIGH PRESSURE ACROSS
THE E GREAT LAKES REGION.
SO NOW WE NEED TO CONSIDER WHETHER OUR REGION DESTABILIZES AND WHAT
FORCING IS AVAILABLE. THE COMBINATION OF MID-LEVEL ENERGY AS SURFACE
HIGH PRESSURE EMERGES OVER THE E GREAT LAKES SUGGESTS SOME LEVEL OF
FORCING WILL BE AVAILABLE. THOUGH A CAP IN PLACE IT WOULD WEAKEN IF
SURFACE TEMPERATURES WARM INTO THE LOW-80S ALLOWING THE CAP TO BE
EASILY BROKEN WITH ANY FORCING. ACROSS OUR REGION THAT DOES NOT
LOOK TO BE THE CASE. MORNING WET WEATHER AND ABUNDANCE OF CLOUDS.
WE DO NOT LOOK TO WARM ENOUGH TO EXCEED CONVECTIVE TEMPERATURE
THRESHOLDS. THUS S NEW ENGLAND REMAINS CAPPED AND THERE IS VERY
LITTLE ELEVATED INSTABILITY WITHIN THE H85-7 TO BE NOTEWORTHY.
THEREFORE ANTICIPATE SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP
INITIALLY WELL TO THE W WITHIN THE BETTER ENVIRONMENT ACROSS
UPSTATE NY AND PA THAT WOULD SWEEP SE WITH THE STEERING-FLOW INTO
W NEW ENGLAND LATE. BUT NOTING THE DISCUSSION ABOVE AND WITH DAYTIME
HEATING DIMINISHING...FEEL ACTIVITY WOULD DISSIPATE INTO OUR REGION.
SO LIGHT SHOWERY WEATHER LINGERS FOR THE EARLY PORTION OF THE DAY
ACROSS THE E-HALF OF NEW ENGLAND. THE SUN POPS OUT BEHIND SCATTERED
TO BROKEN CLOUD DECKS BUT NOT ENOUGH TO DESTABILIZE THE ENVIRONMENT
AS TEMPERATURES WARM INTO THE 70S. SHOWER ACTIVITY IS EXPECTED LATE
FROM THE W ESPECIALLY ACROSS S- AND W-PORTIONS OF THE FORECAST AREA.
SATURDAY NIGHT...
SURFACE HIGH PRESSURE ACROSS THE E GREAT LAKES STRENGTHENS BENEATH
THE ENHANCING RIDGE ALOFT. THE LACK OF DAYTIME HEATING AND A LESS
CONVECTIVELY SUPPORTIVE ENVIRONMENT...A FEW SHOWERS MAY LINGER
MAINLY OVER THE S AND W...OTHERWISE REMAINING DRY. SCATTERED TO
BROKEN CLOUD DECKS LINGER...SO ANTICIPATING A MILD NIGHT OVERALL
WITH LIGHT WINDS OUT OF THE NW. LOWS AROUND THE MID- TO UPPER-50S.
GRADUAL CLEARING TOWARDS MORNING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGHLIGHTS...
* DRY AND SUMMER-LIKE WARMTH SUNDAY AHEAD OF A BACKDOOR COLD FRONT
* MUCH COOLER SUN NIGHT AND MONDAY
* A PERIOD OF SHOWERS LIKELY MON NIGHT AND TUE FOLLOWED BY DRY AND
SEASONABLE WEATHER MID TO LATE NEXT WEEK
SYNOPTIC OVERVIEW AND GUIDANCE EVALUATION...
FAIRLY GOOD AGREEMENT ON THE LARGE SCALE FLOW THIS PERIOD FROM BOTH
ENSEMBLES /GEFS AND EPS/ AND DETERMINISTIC RUNS OF NAM/GFS AND ECMWF.
THUS A MODEL IS IN ORDER TO MINIMIZE MINOR TIMING AND AMPLITUDE
DIFFERENCES. VORTEX ENTERING WESTERN ONTARIO THIS AFTERNOON WILL
TRACK ACROSS SOUTHEAST CANADA THRU SUN AND THEN OVER NEW BRUNSWICK
AND INTO THE GULF OF ME SUN NIGHT AND MON. THIS WILL BE ACCOMPANIED
BY A BACKDOOR FRONT WHICH WILL USHER IN A MUCH COOLER MARITIME
AIRMASS INTO SOUTHERN NEW ENGLAND. AHEAD OF THIS FEATURE A WARM
SECTOR AIRMASS WILL RESIDE OVER THE REGION SUNDAY. THEN BY MON NIGHT
AND ESPECIALLY TUE JET ENERGY AND MOISTURE CURRENTLY OVER THE WEST
COAST ADVECTS NORTHEAST INTO NEW ENGLAND YIELDING OUR NEXT CHANCE OF
WIDESPREAD SHOWERS. THEN MAINLY DRY AND SEASONABLE WEATHER
OVERSPREADS SOUTHERN NEW ENGLAND MID TO LATE NEXT WEEK AS LONG WAVE
TROUGH SETS UP OVER SOUTHEAST CANADA.
DAILY SENSIBLE WEATHER....
SUNDAY...
WARM FRONT LIFTS NORTH ACROSS THE REGION SAT AFTN OR EVENING WITH
WARM SECTOR AIRMASS RESIDING OVER THE AREA SUNDAY. 2 METER MODEL
TEMPS SUPPORT 80-85 TEMPS AWAY FROM THE SHORE. WEAK PGRAD WILL
SUPPORT AFTERNOON COOLING SEABREEZES AT THE COAST ESPECIALLY WITH
WATER TEMPS ONLY IN THE L50S.
SUN NIGHT AND MON...
BY SUN EVENING AND ESPECIALLY SUN NGT A SIGNIFICANT BACKDOOR FRONT
WILL SWEEP ACROSS THE REGION FROM NE TO SW. COULD BE SOME SPOTTY
LIGHT DRIZZLE ESPECIALLY IN RI AND EASTERN MA WITH THIS FEATURE BUT
THE MAIN SENSIBLE WEATHER ITEM WILL BE THE RAPIDLY FALLING TEMPS
INTO THE 40S AND 50S SUN EVENING AND NIGHT. WATER TEMPS IN THE GULF
OF ME AND MAY BAY ONLY IN THE L50S AND WILL ACT AS A SNOWCOVER
ENHANCING THE COOLNESS OF THIS MARITIME AIRMASS. 1027 MB HIGH OVER
THE MARITIMES AND GULF OF ME MON WILL PRECLUDE COOL MARITIME AIRMASS
FROM WARMING MUCH MON WITH HIGHS ONLY 55 TO 60 IN IN EASTERN MA.
STRONG MAY SUNSHINE AND DISTANCE FROM THE OCEAN WILL SUPPORT TEMPS
IN THE L70S ACROSS THE CT RVR VLY/I-91 CORRIDOR OF CT AND MA.
MON NIGHT INTO TUE...
SHORT WAVE ENERGY AND PACIFIC MOISTURE CURRENTLY OVER THE WEST COAST
STATES WILL ARRIVE HERE MON NGT AND ESP TUE. ATTENDING COLD FRONT
WILL ACT ON 1.5"+ PWATS ALONG WITH MARGINAL ELEVATED INSTABILITY TO
YIELD A RISK OF WIDESPREAD SHOWERS LATE MON NIGHT THRU TUE NIGHT. IT
WILL REMAIN RELATIVELY COOL.
WED/THU/FRI...
EVOLVING LONG WAVE TROUGH OVER SOUTHEAST CANADA SUGGEST MAINLY DRY
WEATHER IN SOUTHERN NEW ENGLAND ALONG WITH MILD DAYS AND COOL
NIGHTS.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SATURDAY NIGHT/...
7 PM UPDATE...
NO MAJOR CHANGES FROM 18Z TAFS. ANY SHOWERS HOLD OFF UNTIL AFTER
03Z WEST AND AFTER 09Z EAST. EARLIER DISCUSSION BELOW.
=================================================================
TONIGHT...HIGH CONFIDENCE.
CIGS LOWERING TO LOW-END VFR. SCT -SHRA TOWARDS MORNING MAINLY
ACROSS THE W-HALF OF NEW ENGLAND. S-WINDS.
SATURDAY...MODERATE CONFIDENCE.
SCT-BKN LOW-END VFR CIGS. SCT -SHRA OVER THE E-HALF OF S NEW
ENGLAND DURING THE MORNING. -SHRA MOVING BACK INTO SW-PORTIONS OF
NEW ENGLAND WITH ISOLATED TSRA LATE. BREEZY S-WINDS. GUSTS UP TO
15 KTS ALONG THE SHORES.
SATURDAY NIGHT...LOW CONFIDENCE.
SCT-BKN LOW-END VFR / MVFR CIGS. LOW CONFIDENCE IFR AT THIS TIME.
FRONT DROPPING S THRU TERMINALS WITH SCT -SHRA. S-WINDS BACKING
OUT OF THE NW BY MORNING.
KBOS TAF...MODERATE CONFIDENCE IN TAF.
KBDL TAF...MODERATE CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUN...HIGH CONFIDENCE. VFR. SEABREEZES LIKELY.
SUN NIGHT AND MON...MODERATE CONFIDENCE. WINDS BECOMING E/NE FROM E
TO W SUN NIGHT BEHIND A BACKDOOR FRONT WITH AREAS OF MVFR/IFR
DEVELOPING LATE SUN NIGHT INTO MON MORNING...THEN IMPROVING TO VFR
BUT LOW CLOUDS MAY WAIT UNTIL LATE MON TO LIFT.
TUE...MODERATE CONFIDENCE. AREAS OF MVFR/IFR DEVELOPING IN SCT TO
NUMEROUS SHOWERS AND POSSIBLY A TSTM.
WED...VFR AND DRY WEATHER LIKELY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SATURDAY NIGHT/...MODERATE CONFIDENCE.
INCREASING CHANCES OF SHOWERS WITH BREEZY S-WINDS BEGINNING
SATURDAY MORNING AND CONCLUDING INTO SUNDAY MORNING AS A WARM
FRONT LIFTS ACROSS THE REGION INITIALLY FOLLOWED BY A COLD FRONT
DROPPING S BEHIND WHICH WINDS SHIFT OUT OF THE NW. GUSTS HOLDING
BELOW 20 KTS AS WAVES REMAIN BELOW 5-FEET. LOW CONFIDENCE WITH
RESPECT TO VISIBILITY IMPACTS ON THE WATERS.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUN...HIGH CONFIDENCE. RELATIVELY LIGHT WINDS AND SEAS. ONSHORE
WINDS DEVELOPING NEARSHORE WATERS SUNDAY AS SEABREEZES DEVELOP.
MON AND TUE...HIGH CONFIDENCE. E WINDS ON MON WILL GIVE WAY TO A
RETURN TO S WINDS TUE WITH ANOTHER ROUND OF SHOWERS AS A COLD FRONT
APPROACHES. CONDITIONS MAINLY BELOW SMALL CRAFT ADVISORY THRESHOLDS.
WED...FRONT MOVES OFFSHORE TUE NIGHT/EARLY WED WITH IMPROVING
CONDITIONS BEHIND THE FRONT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/SIPPRELL
NEAR TERM...NOCERA/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...NOCERA
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
336 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WILL BE OFFSHORE THROUGH SATURDAY. LOW PRESSURE FROM
THE UPPER MISSISSIPPI VALLEY WILL MOVE NORTHEASTWARD, WITH AN
ASSOCIATED WARM FRONT CROSSING OUR REGION TONIGHT. A COLD FRONT WILL
THEN SETTLE THROUGH OUR AREA LATE SUNDAY. THE NEXT AREA OF LOW
PRESSURE FROM THE ROCKIES SHOULD TRACK NORTHEASTWARD THROUGH THE
GREAT LAKES REGION, PULLING A COLD FRONT ACROSS OUR AREA TUESDAY.
HIGH PRESSURE WILL THEN GRADUALLY BUILD TOWARD OUR REGION WEDNESDAY
INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LOW PRESSURE LOCATED ALONG A FRONTAL BOUNDARY STRETCHING FROM THE
GREAT LAKES TO THE ROCKIES WILL CONTINUE MOVING NORTHWARD TONIGHT
WITH SOUTHERLY FLOW CONTINUING ACROSS THE REGION. EARLY ON, SOME
SCATTERED S-SSW WIND GUSTS FROM 15-20 MPH ARE POSSIBLE BUT THESE
WILL DIMINISH AS WE LOOSE MIXING CREATED BY DAYTIME HEATING. THESE
LOCALLY STRONGER WIND GUSTS COUPLED WITH LOCAL RH VALUES AROUND
30% MAY BE CLOSE TO RED FLAG CONDITIONS IN A FEW LOCATIONS. ATTM
THIS LOOKS SHORT LIVED AND ISOLATED, WILL NOT ISSUE A FIRE WEATHER
STATEMENT. MESOSCALE MODEL RUNS OF THE HRRR AND RAP SHOW THE
POTENTIAL FOR THE FORMATION OF A FEW LIGHT SHOWERS ALONG THE FRONT
OVERNIGHT. HOWEVER, WITH MOST MODELS OVERDOING DEW POINTS TODAY
DO NOT WANT TO COMMIT ANY HIGHER THAN SLIGHT CHANCE WITH THESE
POTENTIAL SPOTTY SHOWERS. PERIODS OF FAIR AND MOSTLY CLOUDY SKIES
WILL LIKELY ALTERNATE THROUGH THE NIGHT WITH A GENERAL INCREASE IN
CLOUDS BY MORNING. OVERNIGHT LOW TEMPERATURES LOOK TO END UP JUST
UNDER 60.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE FRONTAL BOUNDARY TO OUR NORTH WILL BE CLOSE ENOUGH AS
MOISTURE CONTINUES TO INCREASE TO INCLUDE A CHANCE OF AFTERNOON
THUNDERSTORMS SATURDAY AFTERNOON. ALSO, THE SET-UP ONCE AGAIN LOOKS
FAVORABLE FOR MIXING AND SOME SSW WIND GUSTS CLOSE TO 20 MPH IN THE
AFTERNOON. AREAS ACROSS NORTHERN NJ AND EASTERN PA HAVE THE HIGHEST
CHANCE OF SEEING AFTERNOON AND EVENING POP UP THUNDERSTORMS.
EVEN THOUGH WE HAVE BEEN DRY RECENTLY, PW VALUES WILL INCREASE TO
OVER 1.5 INCHES RESULTING IN HEAVY DOWNPOURS FROM ANY
THUNDERSTORMS. INSTABILITY LOOKS MARGINAL OVERALL, CHARACTERIZED
BY 1000 OR SO MODELED J/KG CAPE. HOWEVER, 0-6 KM BULK SHEAR IS
MODELED TO BE FAIRLY WEAK. OVERALL, INSTABILITY LOOKS SUFFICIENT
FOR SOME THUNDERSTORM DEVELOPMENT ACROSS THE REGION BUT STORM WILL
BE LIMITED WITH MORE OF A PULSE SET-UP LIKELY. AS USUAL, THE NAM
IS MOST AGGRESSIVE SHOWING STEEP LOW LEVEL LAPSE RATES AND SOME
MID-LEVEL DRY AIR WHICH MAY LEAD TO DOWNDRAFTS AND STRONGER WIND
GUSTS IN THE THUNDERSTORMS. THE GFS IS QUITE A BIT MORE STABLE
ATTM. CURRENT THINKING IS THAT SCATTERED STORMS WILL DEVELOP IN
THE AFTERNOON, MORE NUMEROUS CLOSER TO THE FRONT AND BE OF PULSE
NATURE. SPC HAS A MARGINAL RISK AS WELL FOR ANY SEVERE THREAT
TOMORROW AFTERNOON. 925 MB TEMPERATURES ALSO SUGGEST HIGH
TEMPERATURES FORECASTED ON MOST NUMERICAL GUIDANCE SETS LOOK TO
LOW. WILL GO HIGHER WITH FORECASTED HIGH TEMPERATURES, IN THE MID
80`S THAT ARE CONVECTION DEPENDENT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH IN THE WEST
THAT MIGRATES EAST-NORTHEASTWARD WITH TIME AND AN UPPER-LEVEL RIDGE
IN THE EAST. THE RIDGE REMAINS IN PLACE INTO TUESDAY BEFORE
FLATTENING OUT AS A TROUGH MOVES ACROSS THE MIDWEST AND GREAT LAKES.
THIS TROUGH SLIDES ACROSS THE NORTHEAST WEDNESDAY THEN THE FLOW
TURNS MORE ZONAL IN ITS WAKE. THE REGION REMAINS RATHER DRY AND
THERE ARE SOME OPPORTUNITIES FOR RAIN, GENERALLY CENTERED ON SUNDAY
AND LATE MONDAY AND TUESDAY. THE LATTER IS ASSOCIATED WITH A COLD
FRONT THAT IS FORECAST TO SWEEP ACROSS THE AREA TUESDAY. WE USED A
MODEL BLEND FOR SATURDAY NIGHT THROUGH MONDAY, THEN THE 12Z WPC
GUIDANCE OR SUPERBLEND THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE
FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES.
FOR SATURDAY NIGHT AND SUNDAY...THE RIDGE AXIS SHOULD BE APPROACHING
THE AREA SUNDAY MORNING. AN UPPER-LEVEL TROUGH AMPLIFIES ACROSS NEW
ENGLAND AND THIS WILL SEND A FRONTAL BOUNDARY OUR WAY LATE SUNDAY,
BASICALLY IN THE FORM OF A BACKDOOR FRONT AS HIGH PRESSURE BECOMES
ESTABLISHED NEAR THE CANADIAN MARITIMES. FIRST, LINGERING CONVECTION
MAY OCCUR SATURDAY EVENING THEN THIS SHOULD DISSIPATE AS THE NIGHT
WEARS ON. GIVEN THE SYNOPTIC SETUP ON SUNDAY, THE BETTER INSTABILITY
IS FORECAST TO BE PUSHED FARTHER INLAND AND NOT AS HIGH GIVEN SOME
WARMING ALOFT. THE CONVECTION THAT DOES FORM MAY TEND TO BE SLOW
MOVING AS THE FLOW WEAKENS WITH THE RIDGE AXIS NEARLY OVER OUR AREA
DURING SUNDAY, AND WITH PW VALUES OF 1.50-2.00 INCHES LOCALLY HEAVY
RAIN WILL BE POSSIBLE. THE RAIN WOULD BE WELCOMED SINCE THE REGION
CONTINUES TO BE RATHER DRY. ANY CONVECTION SHOULD LESSEN OR EVEN
DISSIPATE SUNDAY NIGHT, THEN A BACKDOOR FRONT MAKES ITS WAY ACROSS
THE AREA AS HIGH PRESSURE STRENGTHENS SOME AND EXTENDS INTO THE
NORTHERN MID ATLANTIC. THIS WILL RESULT IN COOLING FROM AN OCEAN
INFLUENCE SUNDAY NIGHT WITH PERHAPS SOME LOW CLOUDS DEVELOPING. WE
WENT A LITTLE ABOVE MOS GUIDANCE FOR HIGH TEMPERATURES ON SUNDAY AS
THE MODELS MAY BE OVERDOING THE CLOUD COVER.
FOR MONDAY AND TUESDAY...AN UPPER-LEVEL TROUGH IS FORECAST TO BE
LIFTING ACROSS THE GREAT LAKES REGION MONDAY AND ACROSS SOUTHEASTERN
CANADA TUESDAY. THIS WILL DRIVE A COLD FRONT EASTWARD, WHICH SHOULD
CLEAR OUR COAST DURING TUESDAY AS THE UPPER-LEVEL RIDGE FLATTENS
OUT. WE WILL START THE DAY MONDAY WITH AN ONSHORE FLOW BEFORE
SURFACE HIGH PRESSURE SHIFTS EAST AND THE FLOW STARTS TO VEER SOME
AHEAD OF A COLD FRONT. THE INSTABILITY AXIS TO OUR WEST SHOULD MOVE
EASTWARD AHEAD OF THE FRONT, HOWEVER THE INITIAL ONSHORE FLOW SHOULD
TEMPER THAT TO SOME EXTENT. THE PW VALUES ARE FORECAST TO REMAIN
ABOUT IN THE 1.50-2.00 INCH RANGE DESPITE SOME LOW-LEVEL
COOLING/STABILIZATION FROM THE ONSHORE FLOW. THERE MAY NOT BE A LOT
OF CONVECTION AROUND ON MONDAY BUT THIS WILL DEPEND ON THE EXTENSION
OF SURFACE HIGH PRESSURE INTO OUR AREA FROM THE NORTHEAST. WE
CONTINUED THE HIGHER POPS ACROSS THE WESTERN ZONES CLOSER TO THE
BETTER INSTABILITY. THE UPPER-LEVEL FEATURE IS FORECAST TO TRACK
WELL TO OUR NORTHWEST SO THIS MAY REMOVE OUR AREA FROM THE BEST
LARGE SCALE LIFT. THERE SHOULD BE MORE COVERAGE OF CONVECTION ON
TUESDAY AS A COLD FRONT ARRIVES WITH A MOIST ENVIRONMENT WITH SOME
INSTABILITY IN PLACE. THE MAIN DYNAMICS THOUGH MAY FOCUS MORE
FARTHER NORTH.
FOR WEDNESDAY THROUGH FRIDAY...AN UPPER-LEVEL TROUGH SETTLES ACROSS
THE NORTHEAST ESPECIALLY DURING WEDNESDAY BEFORE THE FLOW STARTS TO
TURN MORE ZONAL. AT THE SURFACE, HIGH PRESSURE IS FORECAST TO
GRADUALLY START BUILDING TOWARD OUR AREA DURING THIS TIME FRAME. A
PERIOD OF CAA OCCURS THOUGH FOLLOWING THE COLD FRONTAL PASSAGE
TUESDAY, AND THIS ALONG WITH A TIGHTENED PRESSURE GRADIENT MAY
RESULT IN BREEZY CONDITIONS WEDNESDAY INTO THURSDAY. THE UPPER-LEVEL
FLOW MAY SHARPEN SOME FRIDAY AND WITH A BOUNDARY STALLED WELL TO OUR
SOUTH SOME ENERGY MAY TRY AND TRACK ALONG IT. AS OF NOW, HIGH
PRESSURE IS FORECAST TO BE CLOSE ENOUGH TO OUR AREA THEREFORE WE
WENT WITH A DRY FORECAST ATTM.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS THROUGH MOST OF THE TAF PERIOD. SOME WIND GUSTS FROM
THE S OR SSW MAY APPROACH 15-20 KNOTS AT TIMES BEFORE DIMINISHING BY
00Z. ANOTHER WINDOW IS PRESENT FOR SSW WIND GUSTS AROUND 20 KNOTS
SATURDAY AFTERNOON. CEILINGS OVER 10,000 FEET THROUGH MOST OF TODAY
WILL LOWER SOME OVERNIGHT TO AROUND 5,000 FEET OVERNIGHT. SOME
SHOWERS AND PERHAPS THUNDERSTORMS ARE POSSIBLE TOMORROW AFTERNOON.
STILL TO EARLY TO HONE IN ON AN EXACT TIMEFRAME BROAD -SHRA GROUP
INCLUDED AT PHL ATTM.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...SOME SHOWERS AND THUNDERSTORMS AROUND
WITH POTENTIALLY TIMES OF MVFR/IFR, OTHERWISE VFR. THE GREATER
CHANCE SHOULD BE INLAND.
MONDAY AND TUESDAY...SOME LOW CLOUDS AND SHOWERS POSSIBLE TO START
MONDAY, OTHERWISE TIMES OF MVFR/IFR WITH SOME SHOWERS AND
THUNDERSTORMS ESPECIALLY DURING TUESDAY WITH A COLD FRONT.
WEDNESDAY...VFR OVERALL.
&&
.MARINE...
CONTINUED SOUTHERLY TO SOUTHWESTERLY WINDS UNDER SCA CRITERIA. WIND
GUSTS MAY PEAK AROUND 20 KNOTS SATURDAY AFTERNOON. SEAS WILL BE
BUILDING AS WELL, REACHING FOUR FEET BY SATURDAY AFTERNOON.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...A SOUTHWEST FLOW AHEAD OF A COLD FRONT
WILL BUILD THE SEAS SOME, HOWEVER THE CONDITIONS OVERALL ARE
ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA. THE WINDS
START TO BECOME ONSHORE SUNDAY NIGHT FROM NORTH TO SOUTH AS A
BACKDOOR FRONT MOVES THROUGH.
MONDAY AND TUESDAY...THE WINDS AND SEAS MAY NEAR ADVISORY CRITERIA
ON THE COASTAL WATERS AS THE FLOW IS ONSHORE MONDAY, THEN WEAKENS
SOME TUESDAY AS A COLD FRONT ARRIVES. DENSE FOG IS NOT ANTICIPATED
WITH THE ONSHORE FLOW ATTM.
WEDNESDAY...NORTHWESTERLY FLOW MAY BE A BIT GUSTY ESPECIALLY IN THE
MORNING, OTHERWISE CONDITIONS ARE ANTICIPATED TO BE BELOW ADVISORY
CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...GAINES
SHORT TERM...GAINES
LONG TERM...GORSE
AVIATION...GAINES/GORSE
MARINE...GAINES/GORSE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
304 PM EDT FRI MAY 15 2015
.SYNOPSIS...A HIGHLY AMPLIFIED UPPER LEVEL PATTERN CONTINUES THROUGH
THE U.S. WITH DEEP TROUGHING OVER THE WESTERN HALF OF THE CONUS. A
LITTLE CLOSER TO HOME OVER THE EASTERN HALF OF THE CONUS...
MID/UPPER LEVEL RIDGING EXTENDS NORTHWARD FROM CUBA OVER THE EASTERN
U.S. AND WILL PERSIST FOR THE NEXT COUPLE OF DAYS. THIS UPPER LEVEL
RIDGING IS THE PRIMARY SUPPORT FOR STRONG HIGH PRESSURE THAT IS
SITTING JUST OFF THE VIRGINIA COASTLINE. THIS BROAD AREA OF HIGH
PRESSURE RIDGING WEST SOUTHWEST OVER THE SOUTHEAST U.S. AND FLORIDA
WILL SHIFT SLIGHTLY TO THE EAST AND WILL BE THE MAIN WEATHER
INFLUENCE THROUGH THE WEEKEND. ALL MODELS ARE IN GOOD AGREEMENT WITH
THIS HIGH PRESSURE BLOCKING PATTERN TO CONTINUE OVER THE FLORIDA
PENINSULA.
.SHORT TERM (TONIGHT - SATURDAY)...THE LOCATION OF THE HIGH PRESSURE
CENTER WILL KEEP A PREDOMINANT EASTERLY WIND FLOW ACROSS THE
SUNSHINE STATE. THIS WIND FLOW WILL FAVOR THE EAST COAST SEA BREEZE
BEING THE DOMINANT TRIGGER FOR THUNDERSTORMS ACTIVITY. AS THE EAST
COAST SEA BREEZE BOUNDARY PUSHES WEST...THUNDERSTORMS WILL FIRE UP
OVER THE INTERIOR COUNTIES AND PROGRESSING TOWARD THE WEST COAST.
LATEST HRRR GUIDANCE HAS THE STRONGEST OF THESE STORMS INITIATING
BETWEEN 21-00Z AS THEY COLLIDE WITH THE WEST COAST SEA BREEZE. AS
WE HAVE SEEN OVER THE PAST COUPLE OF DAYS...SOME OF THESE STORMS
COULD BE STRONG PRODUCING HEAVY DOWNPOURS...GUSTY WINDS AND
FREQUENT LIGHTNING. TEMPERATURES ACROSS THE REGION ARE QUITE WARM
AND WILL TOP OUT IN THE UPPER 80S TO LOW 90S REGION WIDE.
&&
.MID/LONG TERM... THE SECOND HALF OF THE WEEKEND WILL FEATURE A
CONTINUATION OF THE SUMMERY PATTERN AS FAIRLY STRONG MID/UPPER LEVEL
RIDGING SITS OVER THE FL PENINSULA...WHILE AT THE SAME
TIME...ATLANTIC HIGH PRESSURE RIDGES BACK WESTWARD ALONG OR JUST
NORTH OF THE I-10 CORRIDOR. THE STACKED RIDGING ALOFT WILL KEEP OUR
TEMPERATURES ON THE WARM SIDE...WITH INLAND LOCATIONS APPROACHING OR
EXCEEDING 90S DEGREES. THE SURFACE HIGH PRESSURE RIDGE TO OUR NORTH
WILL PROVIDE A CONTINUED SYNOPTIC EASTERLY/SOUTHEASTERLY 1000-700MB
FLOW REGIME. AN EAST/SOUTHEAST SYNOPTIC FLOW REGIME FAVORS THE WEST
COAST SEA-BREEZE / I-75 CORRIDOR FOR LATE AFTERNOON/EVENING
CONVECTIVE DEVELOPMENT. EXPECT DECENT CHANCES SUNDAY AFTERNOON (40-
50% POPS) TO SEE A ROUND OF STORMS PROGRESSING EAST TO WEST ACROSS
THE PENINSULA...WITH SIMILAR TO PAST DAYS...THE CONVECTION LIKELY
PEAKING ALONG AND INSIDE THE I-75 CORRIDOR...WHERE LOW LEVEL
FOCUS/CONVERGENCE WILL BE MAXIMIZED. AS WITH ANY SUMMER
PATTERN...NOT EVERYONE IN THIS FAVORED AREA WILL RECEIVE
RAINFALL...BUT MOST EVERYONE SHOULD AT LEAST HAVE STORMS IN THE
VICINITY LATE IN THE DAY.
MONDAY STILL LOOKS TO BE SOMEWHAT OF A TRANSITION DAY AS THE SURFACE
RIDGE BOTH WEAKENS A BIT AND SETTLES SOUTHWARD. THEREAFTER...THE MID-
WEEK WILL CONTINUE THE TRANSITION WITH THE UPPER FLOW FLATTENING OUT
ALONG THE NORTHERN GULF COAST. TUESDAY SEES A WEAK/VARIABLE SYNOPTIC
FLOW LEVEL FLOW WHICH FAVORS SEA-BREEZE CONVERGENCE THROUGH THE
CENTER OF THE STATE IN THE LATE AFTERNOON. THEREFORE...ALTHOUGH A
FEW STORMS ARE POSSIBLE CLOSER TO THE COAST EARLY IN THE
AFTERNOON...THE BETTER RAIN CHANCES WILL EXIST INLAND FROM THE I-75
CORRIDOR DURING THE LATE AFTERNOON/EVENING HOURS.
FOR WEDNESDAY THROUGH FRIDAY...A WEAK FRONT SAGS DOWN TOWARD NORTH
FLORIDA. DO NOT GET TOO EXCITED. THIS FRONT IS NOT GOING TO PASS
THROUGH OUR REGION AND BRING US ANY COOLER OR DRIER WEATHER.
HOWEVER...IT WILL ACT TO TURN OUR LOCAL 1000-700MB SYNOPTIC FLOW
SHIFTS MORE TO THE NORTHWEST OR WEST. THIS FLOW REGIME FAVORS THE
FLORIDA EAST COAST FOR ORGANIZED LATE DAY CONVECTION. WILL HAVE THE
HIGHEST RAIN CHANCES WELL INLAND FOR THESE DAYS FINAL DAYS OF THE
FORECAST WEEK.
&&
.AVIATION...
OVERALL VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. WINDS
WILL SHIFT TO THE WEST SOUTHWEST LATER THIS AFTERNOON AS THE SEA
BREEZE SETS UP. SCATTERED SHOWERS AND STORMS ARE POSSIBLE DURING
THE AFTERNOON HOURS SO WILL COVER THIS WITH VCTS STARTING BETWEEN
19-21Z. STORMS WILL DISSIPATE AFTER SUNSET AND THE WINDS WILL DIE
DOWN BECOMING LIGHT AND VARIABLE OVERNIGHT.
&&
.MARINE...OVERALL EASTERLY WIND FLOW WILL CONTINUE THROUGH THE
WEEKEND AS HIGH PRESSURE OFF THE VIRGINIA COAST RIDGES ACROSS THE
FLORIDA PENINSULA AND INTO THE GULF COAST WATERS. THE ONLY EXPECTED
CHANGE WILL BE ALONG THE COAST WHERE THE DAILY AFTERNOON SEA BREEZE
PATTERN SETS UP. WINDS WILL GENERALLY STAY BELOW 15 KNOTS AND SEAS
BELOW 3 FEET EXCEPT FOR DURING THE OVERNIGHT HOURS WHERE EASTERLY
SURGES WILL INCREASE WINDS TO SCEC ESPECIALLY OVER THE NORTHERN
COASTAL WATERS. THE GRADIENT WILL SLACKEN BY TUESDAY AS HIGH
PRESSURE MOVES INTO THE GULF OF MEXICO CAUSING A DECREASE IN WINDS
AND SEAS. THE WEATHER WILL REMAIN OVERALL DRY EXCEPT FOR LATE
AFTERNOON / EVENING THUNDERSTORMS THAT MAY MOVE FROM THE LAND OVER
THE COASTAL WATERS.
&&
.FIRE WEATHER...HIGH PRESSURE IN THE WESTERN ATLANTIC WILL KEEP AN
EAST TO SOUTHEAST WIND FLOW OVER THE FLORIDA PENINSULA THROUGH THE
WEEKEND. THIS WILL KEEP ABUNDANT LOW LEVEL MOISTURE OVER THE AREA
THAT WILL MAINTAIN RELATIVE HUMIDITY LEVELS ABOVE ANY CRITICAL
THRESHOLD. AFTERNOON RAIN SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
EACH AFTERNOON THIS WEEKEND WITH THE STRONGER STORMS OCCURRING OVER
THE WEST COAST FROM TAMPA BAY SOUTHWARD. NO SIGNIFICANT FOG IS
EXPECTED THROUGH THE NEXT COUPLE OF DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 89 73 89 / 20 60 40 50
FMY 72 92 72 91 / 30 50 30 50
GIF 72 90 71 91 / 10 50 20 40
SRQ 71 89 72 87 / 40 50 40 50
BKV 70 89 69 91 / 10 60 40 50
SPG 75 89 75 89 / 40 50 40 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...74/WYNN
MID/LONG TERM/DECISION SUPPORT...14/MROCZKA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
254 PM CDT FRI MAY 15 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 253 PM CDT FRI MAY 15 2015
THUNDERSTORMS HAVE BEEN ON THE INCREASE ACROSS MISSOURI THE LAST FEW
HOURS AS A SHORTWAVE LIFTS NORTHEAST...WITH MORE ISOLATED CONVECTION
IN THE SOUTHEASTERN CWA. NOT MUCH HOLDING THESE STORMS BACK AS
SURFACE BASED CAPE`S ARE OVER 2500 J/KG...BUT VERY LITTLE WIND SHEAR
ALOFT IS RESULTING IN A MORE PULSE-TYPE STORM ENVIRONMENT. HRRR
MODEL LIFTS THE BULK OF THESE STORMS THROUGH THE FORECAST AREA BY 8-
9 PM. MODEL GUIDANCE BEYOND THAT GETS A BIT MORE DISJOINTED...AS
SEVERAL OF THE HIGH-RESOLUTION MODELS PRETTY MUCH DRY THINGS OUT
ALTHOUGH THE HRRR TRIES TO BRING ANOTHER LOBE THROUGH LATE EVENING.
HAVE LARGELY GONE WITH 30-40% POP`S THROUGH THE NIGHT IN MOST AREAS
EXCEPT FOR SOME HIGHER VALUES EARLY EVENING ACROSS THE SOUTHWEST CWA
WITH THE CURRENT ACTIVITY. HOURLY TEMPERATURES WILL BE TRICKY AS THE
STORMS WILL CAUSE SOME TEMPORARY COOLDOWNS...BUT OVERALL LOWS IN THE
MID 60S REQUIRED LITTLE CHANGE FROM THE PREVIOUS FORECAST.
&&
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 253 PM CDT FRI MAY 15 2015
- KCHI 150802
WRKAFD
MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER
LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS,
ADVECTIVING DEEP MOISTURE PLUME NORTHWARD FROM TX INTO THE CENTRAL
MIDWEST. SURFACE DATA SHOWS VERY MOIST AIRMASS OVER IL REGION, WITH
2500 CAPE, DEW POINTS APPROACHING 70 AND TEMPS IN LOWER 80S. WITH
THE PROGGED CONTINUING OF THE MOISTURE FETCH NORTHWARD TONIGHT
THROUGH MUCH OF STATE SATURDAY, THERE WILL BE LITTLE CHANGE IN
RESULT FOR THE START OF WEEKEND.
EXPECT SCATTERED STORMS TONIGHT INTO DAY SATURDAY, BUT WILL LIMITED
SHEAR AVAILABLE, SEVERE POTENTIAL WILL BE ON THE LOCALLIZED SCALE.
BY SUNDAY THOUGH, PATTERN CHANGES AS THE UPPER LOW STARTS TO MOVE
NORTHEAST SATURDAY NIGHT. BY SUNDAY IT REACHES THE DAKOTAS AND
ANOTHER WAVE ROTATES EAST AROUND THE LOW INTO THE PLAINS. THIS WILL
GET THE FRONT MOVING EAST, PROVIDING AN INCREASE IN SHEAR AND
CONVERGENCE INTO THE IL REGION ON SUNDAY. WITH LITTLE CHANGE IN
MOISTURE, THE AFTERNOON AND EVENING WILL BE THE BEST CHANCES FOR
ORGANIZED SEVERE. AMOUNT OF SHEAR AND STRENGTH OF UPPER LEVEL
SUPPORT IN THE AREA STILL A LITTLE UNCERTAIN, BUT A SLIGHT RISK OF
SEVERE STILL IS SUPPORTABLE.
DRYING SUNDAY NIGHT AS UPPER WAVE MOVES EAST WILL CLEAR PCPN CHANCES
FOR MONDAY. COOLER AIR MOVES IN AND WILL SOME WEAK RIDGING ALOFT,
QUITE WEATHER IS RULE EARLY IN THE WEEK. A WEAK UPPER LEVEL WAVE
MOVES OUT OF STILL STAGNATE UPPER TROUGH IN THE WESTERN ROCKES,
WHICH WILL BRING CHANCE OF PCPN WED TO THURS, BUT WITH DRIER, MORE
STABLE AIR IN AREA, SLIGHT CHANCE POPS ARE THE RESULT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1237 PM CDT FRI MAY 15 2015
BROKEN MVFR CEILINGS BECOME A BIT MORE WIDESPREAD AS CLEAR SLOT
IN THE KSPI-KCMI CORRIDOR BEGAN SEEING DIURNAL DEVELOPMENT OVER
THE LAST COUPLE HOURS. AM EXPECTING THIS TO LIFT UPWARD ABOVE 3000
FEET EARLY THIS AFTERNOON. MORE PERSISTENT LOWER CEILINGS WHICH
HAD PLAGUED KPIA MOST OF THE MORNING ARE FINALLY LIFTING UPWARD
THOUGH. CONVECTION ACROSS MISSOURI IS TRACKING NORTHEAST AND IS
PROJECTED TO START AFFECTING KSPI-KDEC AROUND 20-21Z AND
KPIA/KBMI TOWARD 23Z. HAVE ADDED VCTS AT ALL SITES AND WILL
MONITOR FOR AMENDING TO ADD PREVAILING/TEMPO GROUPS OF LOWER
CONDITIONS AS THE STORMS BECOME MORE ORGANIZED. SEVERAL OF THE
HIGH-RESOLUTION MODELS LIFT MUCH OF THE CONVECTION OUT OF THE
CENTRAL ILLINOIS TAF SITES BY MID EVENING OR SO. HAVE ADDED SOME
MORE MVFR CEILINGS OVER EAST CENTRAL ILLINOIS OVERNIGHT BASED ON
NAM MODEL SOUNDINGS. THESE SHOULD LIFT BY MID MORNING SATURDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...GOETSCH
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1238 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1025 AM CDT FRI MAY 15 2015
CLUSTERS OF SHOWERS/STORMS ACROSS THE SOUTHEAST THIRD OF THE CWA
HAVE LARGELY EXITED THE AREA...HOWEVER REGIONAL RADAR SHOWS SOME
WIDELY SCATTERED SHOWERS EXTENDING SOUTHWEST FROM THERE TOWARD THE
SOUTHERN ST. LOUIS METRO ALONG THE EDGE OF A NARROW CLEAR SLOT.
MAIN FRONTAL BOUNDARY CONTINUES TO LIFT NORTHWARD AND MOST OF THE
CWA NOW HAS DEW POINTS WELL INTO THE 60S. SOME LOW CLOUDS HAVE
BEEN PERSISTING ACROSS THE ILLINOIS RIVER VALLEY...ALTHOUGH
CEILINGS SHOULD RISE OVER THE NEXT COUPLE HOURS.
MAIN CHALLENGE FOR TODAY IS WITH TIMING OF REDEVELOPMENT. UPPER
WAVE ACROSS THE CENTRAL PLAINS EXPECTED TO TRACK INTO WESTERN
MISSOURI LATER TODAY...WITH THE NAM AND HRRR BOTH DEVELOPING
CONVECTION BY MID AFTERNOON. HOWEVER...THE HRRR ALSO LIFTS
CONVECTION CURRENTLY IN SOUTHERN MISSOURI/NORTHERN ARKANSAS
NORTHWARD AND BRINGS IT NEAR A JACKSONVILLE TO EFFINGHAM LINE BY
MID AFTERNOON. THE PREVIOUS AFTERNOON POP GRIDS HAD THAT
PARTICULAR SCENARIO ALREADY IN PLACE...AND RECENT UPDATES
CONTINUED THAT GENERAL TREND EXCEPT TO INCREASE THE POP`S A BIT
MID/LATE AFTERNOON.
&&
.SHORT TERM...(TODAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
07Z/2AM SURFACE ANALYSIS SHOWS A 1012MB LOW OVER WESTERN
WISCONSIN...WITH A WARM FRONT ARCING SOUTHEASTWARD INTO NORTH-
CENTRAL ILLINOIS. SURFACE WINDS AT ALL KILX OB SITES HAVE VEERED TO
THE S/SW...SO THINK FRONT IS NOW JUST NORTH OF THE AREA ALONG A
MOLINE TO KANKAKEE LINE. WIDELY SCATTERED SHOWERS CONTINUE SOUTH OF
THE FRONT...ALTHOUGH RADAR IS SHOWING A DISTINCT DIMINISHING TREND.
WITH WARM FRONT LIFTING FURTHER NORTHWARD THIS MORNING...FORCING FOR
ADDITIONAL CONVECTION WILL BE WEAK. AS A RESULT...THINK ONLY
ISOLATED SHOWERS/THUNDER WILL BE PRESENT ACROSS THE AREA THROUGH
MIDDAY. AS THE DAY PROGRESSES...A WEAK SHORT-WAVE TROUGH NOTED ON
LATEST WATER VAPOR IMAGERY OVER TEXAS WILL APPROACH FROM THE
SOUTHWEST...PROVIDING ENHANCED LIFT AND GREATER AREAL COVERAGE OF
CONVECTION. 4KM WRF-NMM SHOWS SCATTERED SHOWERS/THUNDER DEVELOPING
IN ADVANCE OF THE WAVE ACROSS MISSOURI BY EARLY AFTERNOON...THEN
SPREADING ACROSS THE SOUTHERN HALF OF THE CWA BY MID TO LATE
AFTERNOON. HAVE FASHIONED THE POPS ACCORDINGLY...FEATURING ONLY
ISOLATED SHOWERS/THUNDER ALONG AND NORTH OF I-74...WITH SCATTERED
WORDING FURTHER SOUTH ACROSS THE REMAINDER OF THE AREA. WILL BE A
WARM AND HUMID DAY...WITH AFTERNOON HIGH TEMPERATURES TOPPING OUT IN
THE UPPER 70S AND LOWER 80S.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
TEXAS WAVE WILL TRACK THROUGH THE AREA TONIGHT...TRIGGERING WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS. DESPITE MODEST LIFT ASSOCIATED
WITH THIS FEATURE...WILL ONLY CARRY LOW CHANCE POPS AS DAYTIME
INSTABILITY WANES. ANOTHER SHORT-WAVE EMBEDDED WITHIN THE DEEP
SOUTHWESTERLY FLOW PATTERN WILL APPROACH FROM THE SOUTHWEST ON
SATURDAY...WITH MODELS DISAGREEING ON HOW MUCH PRECIP IT WILL
GENERATE. MOST MODELS HAVE BEEN SHOWING THIS FEATURE TRACKING
TOWARD THE OHIO RIVER VALLEY FOR THE PAST FEW RUNS...WHICH WOULD
MEAN THE STRONGEST LIFT AND HIGHEST RAIN CHANCES WOULD BE FOCUSED
ACROSS THE SOUTHEAST CWA. LATEST NAM HAS STRAYED FROM THAT THINKING
AND NOW SPREADS QUITE A BIT OF PRECIP ACROSS THE ENTIRE AREA. HAVE
REJECTED THIS SOLUTION IN FAVOR OF THE CONSENSUS...WHICH STILL KEEPS
THE MAIN INFLUENCE OF THE WAVE FURTHER SOUTHEAST. AS A
RESULT...WILL FOCUS LIKELY POPS ALONG/SOUTH OF I-70 ON SATURDAY WITH
CHANCE POPS FURTHER NORTH AND WEST.
WESTERN CONUS UPPER LOW IS STILL EXPECTED TO TRACK INTO THE NORTHERN
PLAINS BY SUNDAY...WITH TRAILING COLD FRONT TRIGGERING WIDESPREAD
SHOWERS AND THUNDERSTORMS. MOST MODELS INDICATE STRONG/SEVERE
CONVECTION ACROSS NEBRASKA/KANSAS/OKLAHOMA SATURDAY AFTERNOON AND
EVENING...WITH STORMS TRACKING EASTWARD AND WEAKENING AS THEY
APPROACH THE MISSISSIPPI RIVER OVERNIGHT. THINK REMNANT
SHOWERS/THUNDERSTORMS WILL SPILL INTO WEST-CENTRAL ILLINOIS SUNDAY
MORNING BEFORE DISSIPATING TOWARD MIDDAY. ADDITIONAL DEVELOPMENT
WILL BE LIKELY LATER IN THE DAY...HOWEVER DEGREE OF
DESTABILIZATION IS IN QUESTION DUE TO CLOUD DEBRIS FROM THE
MORNING PRECIP. WITH SURFACE DEWPOINTS WELL INTO THE 60S...ANY
AMOUNT OF HEATING WILL EASILY CREATE SBCAPES OF 1500 TO 2500J/KG.
IN ADDITION...0-6KM BULK SHEAR WILL INCREASE TO OVER 40KT AS THE
WESTERN TROUGH APPROACHES. STILL DIFFICULT TO PIN DOWN EXACT
SEVERE WEATHER THREAT...HOWEVER THINK THUNDERSTORMS WILL BE LIKELY
WITH A FEW POSSIBLY BECOMING SEVERE DURING THE AFTERNOON AND
EVENING. MAIN THREATS WOULD BE DAMAGING WIND GUSTS AND LARGE
HAIL.
WHILE ACTUAL COLD FRONT REMAINS WELL TO THE WEST...MOST
MODELS SUGGEST THE MAIN BAND OF ACTIVE CONVECTION WILL SHIFT E/SE
INTO THE OHIO RIVER VALLEY SUNDAY NIGHT. WILL THEREFORE CONFINE
CHANCE POPS TO AREAS EAST OF THE I-55 CORRIDOR. FRONT WILL PUSH
THROUGH THE AREA ON MONDAY...WITH POTENTIAL RE-DEVELOPMENT OF
STORMS ALONG THE BOUNDARY LATER IN THE DAY. WILL HANG ON TO LOW
CHANCE POPS ACROSS THE FAR E/SE ACCORDINGLY...HOWEVER IT APPEARS
GREATEST CHANCE FOR ADDITIONAL THUNDER WILL BE FURTHER EAST INTO
INDIANA AND KENTUCKY.
ONCE THE FRONT PASSES...UNSEASONABLY STRONG CANADIAN HIGH PRESSURE
WILL SETTLE INTO THE REGION NEXT WEEK. WITH 850MB TEMPS PROGGED TO
DROP INTO THE SINGLE DIGITS...CORRESPONDING HIGHS WILL FALL BACK
INTO THE 60S AND LOWS WILL DIP INTO THE 40S TUESDAY THROUGH
THURSDAY. A WEAK UPPER-LEVEL WAVE WILL TRY TO APPROACH FROM THE
WEST BY MID-WEEK...BUT THINK IT WILL HAVE LITTLE IMPACT ON THE
WEATHER DUE TO THE COOL/DRY AIRMASS ACROSS THE REGION. GFS IS
AGGRESSIVELY PUSHING SHOWERS INTO THE AREA WEDNESDAY/WEDNESDAY
NIGHT...BUT AM GOING WITH A DRY FORECAST AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1237 PM CDT FRI MAY 15 2015
BROKEN MVFR CEILINGS BECOME A BIT MORE WIDESPREAD AS CLEAR SLOT
IN THE KSPI-KCMI CORRIDOR BEGAN SEEING DIURNAL DEVELOPMENT OVER
THE LAST COUPLE HOURS. AM EXPECTING THIS TO LIFT UPWARD ABOVE 3000
FEET EARLY THIS AFTERNOON. MORE PERSISTENT LOWER CEILINGS WHICH
HAD PLAGUED KPIA MOST OF THE MORNING ARE FINALLY LIFTING UPWARD
THOUGH. CONVECTION ACROSS MISSOURI IS TRACKING NORTHEAST AND IS
PROJECTED TO START AFFECTING KSPI-KDEC AROUND 20-21Z AND
KPIA/KBMI TOWARD 23Z. HAVE ADDED VCTS AT ALL SITES AND WILL
MONITOR FOR AMENDING TO ADD PREVAILING/TEMPO GROUPS OF LOWER
CONDITIONS AS THE STORMS BECOME MORE ORGANIZED. SEVERAL OF THE
HIGH-RESOLUTION MODELS LIFT MUCH OF THE CONVECTION OUT OF THE
CENTRAL ILLINOIS TAF SITES BY MID EVENING OR SO. HAVE ADDED SOME
MORE MVFR CEILINGS OVER EAST CENTRAL ILLINOIS OVERNIGHT BASED ON
NAM MODEL SOUNDINGS. THESE SHOULD LIFT BY MID MORNING SATURDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS DES MOINES IA
425 PM CDT FRI MAY 15 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 425 PM CDT FRI MAY 15 2015
LOW PRESSURE CONTINUES TO WORK ITS WAY OFF OF THE ROCKIES AND INTO
NE COLORADO AND SW NEBRASKA THIS AFTERNOON AND WILL BE THE MAIN
DRIVER OF WEATHER OVER THE WEEKEND...BUT NOT IN THIS PERIOD.
INSTEAD...VORTICITY ASSOCIATED WITH A SHORTWAVE MOVING UP THROUGH
THE PLAINS HAS KICKED OFF CONVECTION IN E KANSAS AND W AND C
MISSOURI. THETA-E ADVECTION IS NOT SIGNIFICANT WITH THE CONVECTION
IN KANSAS...BUT IS MORE SO IN MISSOURI AND IS EXPECTED TO INCREASE
LATER THIS AFTERNOON AND EVENING AS THE LOW LEVEL FLOW INCREASES AND
HELPS KEEP SHOWERS AND STORMS GOING AS DAYTIME HEATING AND
INSTABILITY BEGINS TO WANE. A FEW STORMS MAY CONTAIN SEVERE HAIL AND
HIGH WINDS EARLY THIS EVENING WITH CAPE VALUES IN EXCESS OF 1500-
2000 J/KG...WIDESPREAD SEVERE IS NOT EXPECTED THOUGH GIVEN THE LACK
OF SUPPORTIVE SHEAR. SHOWERS AND STORMS ARE ALREADY IN THE SW CWA
AND WILL CONTINUE TO MOVE NORTHEAST...REACHING THE DES MOINES METRO
AROUND 00Z...AND THE WATERLOO AROUND 03Z...WEAKENING AS THE EVENING
GOES ON. THE HIGH-RES MODELS HAVE NOT BEEN IN GREAT AGREEMENT...WITH
THE HRRR OVERLY AGGRESSIVE IN PROGRESSION. THE ARW-EAST HAS THE
BEST HANDLE ON CONVECTION CURRENTLY...AND HAVE LEANED THAT WAY FOR
POPS THIS EVENING. AM EXPECTING LOCALLY DENSE FOG OVERNIGHT...AS
WELL...WITH HIGH DEW PTS FROM INCOMING PRECIP AND SOLID MOISTURE
TRANSPORT THROUGH THE EVENING AND OVERNIGHT...BUT WILL REFRAIN
FROM WIDESPREAD FOR NOT AND DENOTE PATCHY FOG.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 425 PM CDT FRI MAY 15 2015
DYNAMIC UPPER LEVEL SYSTEM EXTENDING FROM SOUTHERN CALIFORNIA
THROUGH IDAHO WILL SEGMENT INTO TWO SECTIONS WITH ONE SEGMENT
LIFTING INTO WYOMING AND MONTANA AND LINGERING THERE THROUGH
SUNDAY. THE STRONGER SEGMENT WILL MOVE EAST THROUGH THE DESERT
SOUTHWEST ON SUNDAY THEN LIFT NORTHEAST THROUGH THE TEXAS
PANHANDLE LATE SATURDAY THEN OVER EASTERN NEBRASKA BY EARLY
SUNDAY. THE INITIAL SHORTWAVE THAT WILL MOVE ACROSS IOWA OVERNIGHT
WILL LEAVE SOME STABILITY THROUGH THE MORNING WITH THE PASSAGE OF
MID LEVEL DRY AIR. INSTABILITY WILL DEVELOP BY THE AFTERNOON
THROUGH SFC HEATING HOWEVER NO GOOD FORCING MECHANISM WILL BE
AVAILABLE AND THIS SHOULD LIMIT THE AREAL COVERAGE OF THUNDERSTORM
DEVELOPMENT. THE STRONGER THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING WILL INITIALIZE ACROSS NEBRASKA AND KANSAS. THESE STORMS
SHOULD MOVE INTO WESTERN IOWA SATURDAY NIGHT AS THE UPPER LEVEL
SYSTEM ADVANCES NORTHEAST. A FEW SEVERE STORMS ARE POSSIBLE AS
THIS ACTIVITY ARRIVES.
THE THUNDERSTORM POTENTIAL ON SUNDAY EARLY IN THE DAY WILL BE FROM
LINGERING ACTIVITY FROM THE OVERNIGHT. A BOUNDARY WILL MOVE
THROUGH IN THE MORNING AND WILL BRING DRIER AIR TO THE STATE.
TEMPERATURES SHOULD WARM IN TO THE 70S AND 80S BEHIND THE BOUNDARY
HOWEVER THUNDERSTORM CHANCES WILL BE LIMITED BY THE DRIER AIR. THE
BEST POTENTIAL FOR THUNDERSTORMS WILL BE ACROSS NORTHERN IOWA
DURING THE AFTERNOON IN CLOSER VICINITY TO THE UPPER LEVEL COLD
CORE. AN ATTENDANT HAIL THREAT WOULD BE POSSIBLE WITH ANY
AFTERNOON STORMS.
THE REMAINDER OF THE EXTENDED WILL BE COOL WITH 850 MB
TEMPERATURES IN THE 0-5C RANGE THROUGH WEDNESDAY. BREEZY AND COOL
CONDITIONS ON MONDAY. NOT EXPECTING ANY SHOWERS DESPITE THE
CYCLONIC FLOW WITH A GOOD INVERSION IN PLACE ABOVE THE BOUNDARY
LAYER. ANOTHER PUSH OF COOLER AIR TUESDAY NIGHT AND WEDNESDAY
ALONG WITH ANOTHER CHANCE FOR SHOWERS.
&&
.AVIATION...15/18Z
ISSUED AT 1234 PM CDT FRI MAY 15 2015
VSBYS UP ACROSS THE STATE WELL WITHIN VFR WILL REMAIN THROUGH THE
REMAINDER OF THE DAY. CIGS WILL CONTINUE TO HOVER AROUND VFR/MVFR
AT MOST LOCATIONS THROUGH TAF PERIOD. STORMS WILL MOVE THROUGH
OTM/DSM/FOD/ALO SITES THIS AFTERNOON/EVENING...TEMPORARILY
DROPPING CONDITIONS INTO MVFR AND IFR...AND EXITING ALL SITES BY
AROUND 03Z. EXPECT VSBYS TO DROP AGAIN OVERNIGHT WITH FOG...BUT
WILL HOLD OFF ON DROPPING VSBYS BELOW 1 MILE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...DONAVON
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1241 PM CDT FRI MAY 15 2015
...UPDATED AVIATION DISCUSSION...
.UPDATE...
ISSUED AT 958 AM CDT FRI MAY 15 2015
CLEANED UP GRIDS A BIT FROM THE FOG THIS MORNING AND ADJUSTED
SKY/TEMPS ACCORDINGLY. ALSO MAY SEE A BIT COOLER MAX TEMPS ACROSS
THE NORTH WITH SOME ADDED IN CIRRUS FROM A FEW POP UP
THUNDERSTORMS ACROSS NORTHWEST IOWA...SO ADJUSTED NORTHERN CWA
TEMPS DOWN A BIT. LINE OF STORMS ALREADY ACROSS ERN NE ON NOSE OF
THETA-E ADVECTION WHICH IS EXPECTED TO BE ORIENTED MORE INTO
SOUTHERN/WESTERN CWA BY THIS AFTERNOON. THEREFORE DID INCREASE
POPS A BIT IN THAT REGION AND ACROSS THE SOUTH FOR THIS EVENING.
&&
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/18Z
ISSUED AT 1234 PM CDT FRI MAY 15 2015
VSBYS UP ACROSS THE STATE WELL WITHIN VFR WILL REMAIN THROUGH THE
REMAINDER OF THE DAY. CIGS WILL CONTINUE TO HOVER AROUND VFR/MVFR
AT MOST LOCATIONS THROUGH TAF PERIOD. STORMS WILL MOVE THROUGH
OTM/DSM/FOD/ALO SITES THIS AFTERNOON/EVENING...TEMPORARILY
DROPPING CONDITIONS INTO MVFR AND IFR...AND EXITING ALL SITES BY
AROUND 03Z. EXPECT VSBYS TO DROP AGAIN OVERNIGHT WITH FOG...BUT
WILL HOLD OFF ON DROPPING VSBYS BELOW 1 MILE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BEERENDS
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
147 PM CDT FRI MAY 15 2015
...UPDATED SHORT TERM AND LONG TERM DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 141 PM CDT FRI MAY 15 2015
RAP AND NGM BOTH SUPPORTING A SURFACE BOUNDARY EXTENDING FROM
NEAR HAYS TO COLDWATER AT 00Z SATURDAY WITH WEAK 0-1KM MOISTURE
CONVERGENCE OCCURRING ALONG THIS BOUNDARY. 0-6KM SHEAR IN THIS
AREA WILL BE FROM 20 TO 25 KNOTS AND CAPE VALUES ARE EXPECTED TO
RANGE FROM 1000 TO 1500 J/KG. RAP HAS SOME CIN REMAINING IN THIS
AREA GIVEN THE WARM MID LEVEL TEMPERATURES WHILE THE NAM SUGGESTS
A FEW ISOLATED THUNDERSTORMS BEING POSSIBLE. AT THIS TIME GIVEN
THE CU DEVELOPING WILL RETAIN MENTION OF ISOLATED THUNDERSTORMS
GOING ALONG AND EAST OF THIS BOUNDARY EARLY TONIGHT. ANOTHER AREA
OF THUNDERSTORMS WILL DEVELOP EARLY THIS EVENING NEAR THE COLORADO
BORDER. THIS AREA WILL HAVE MORE FAVORABLE UPPER LEVEL DYNAMICS
ALONG WITH IMPROVING WARM AIR ADVECTION NEAR THE NOSE OF A 50 KNOT
850MB JET BASED ON THE 12Z NAM. THESE STORMS WILL MARCH EAST
ACROSS WESTERN KANSAS OVERNIGHT WITH A FEW OF THESE STORMS BEING
CAPABLE OF PRODUCING SMALL HAIL AND WIND GUSTS OF UP TO 55 MPH.
BY EARLY SATURDAY MORNING THIS THUNDERSTORM ACTIVITY WILL BE MOVE
INTO CENTRAL KANSAS AS AN UPPER LEVEL TROUGH CROSSES EASTERN
COLORADO AND NORTHEAST NEW MEXICO. 12Z NAM SHOWING 0-6KM SHEAR
SATURDAY AFTERNOON RANGING FROM 40 TO NEAR 50 KNOTS AND CAPE
VALUES WILL RANGING FROM 1500 TO 2500 J/KG AHEAD OF THIS
UPPER LEVEL SYSTEM. THIS CONTINUES TO SUPPORT THE CHANCE FOR
SEVERE THUNDERSTORMS ALONG AND EAST OF WHERE THIS DRY LINE WILL BE
LOCATED BETWEEN 18Z AND 21Z SATURDAY. LARGE HAIL AND STRONG
DAMAGING WINDS CURRENTLY APPEARS TO BE THE MAIN HAZARD ALONG WITH
PERIODS OF HEAVY RAINFALL. A FEW TORNADOES WILL ALSO BE POSSIBLE
LATE SATURDAY AND EARLY SATURDAY NIGHT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 141 PM CDT FRI MAY 15 2015
EVENING CONVECTION WILL TAPER OFF EARLY SATURDAY NIGHT AS THE
UPPER LEVEL TROUGH LIFTS NORTHEAST INTO NORTH CENTRAL KANSAS AND
THE DRY LINE/COLD FRONT MOVES SOUTH AND EAST. WESTERLY DOWNSLOPE
FLOW WILL DEVELOP BY EARLY SUNDAY MORNING AND CONTINUE THROUGH THE
REMAINDER OF THE WEEKEND AS ANOTHER UPPER LEVEL TROUGH MOVES OUT
OF SOUTHERN WYOMING AND INTO THE CENTRAL HIGH PLAINS. 700MB TO
500MB LAPSE RATES WILL VARY FROM 7 TO 8C/KM AHEAD OF THIS UPPER
WAVE, HOWEVER MOISTURE APPEARS SOMEWHAT LIMITED EARLY SUNDAY
NIGHT. ALTHOUGH A FEW SPRINKLE MAY BE POSSIBLE NEAR AND NORTH OF
THE INTERSTATE 70 CORRIDOR, AT THIS TIME WILL ONLY INCREASE CLOUD
COVER AT THIS TIME SUNDAY EVENING GIVEN THE LIMITED MOISTURE IN
THE LOWER LEVELS.
GIVEN THE WESTERLY DOWNSLOPE FLOW AND 850MB TEMPERATURES AT 00Z
MONDAY WILL RANGING FROM 18C TO NEAR 24C THE PREVIOUS FORECAST
STILL LOOKS ON TRACK WITH HIGHS RANGING FROM THE UPPER 70S IN WEST
CENTRAL KANSAS TO THE LOWER 80S IN SOUTH CENTRAL KANSAS.
EARLY NEXT WEEK AN UPPER LEVEL RIDGE AXIS WILL CROSS WESTERN
KANSAS AS AN AREA OF HIGH PRESSURE AT THE SURFACE BUILDS INTO
KANSAS PLAINS. TEMPERATURES ON MONDAY WILL AVERAGE AROUND 10F
COOLER WHEN COMPARED TO THE HIGHS ON SUNDAY GIVEN THE 900 TO
850MB TEMPERATURE TRENDS FROM 00Z MONDAY AND 00Z TUESDAY.
CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS AN UPPER LEVEL
TROUGH/LOW MOVES EAST ACROSS THE SOUTHWEST UNITED STATES. IN
ADDITION TO THE INCREASING CLOUDS THERE WILL ALSO BE A CHANCE FOR
PRECIPITATION TO DEVELOP BY EARLY TUESDAY GIVEN A MOIST
SOUTHEASTERLY UPSLOPE FLOW, WARM AIR ADVECTION, AND IMPROVING
ISENTROPIC LIFT ACROSS SOUTHWEST KANSAS. HIGH PRECIPITATION
CHANCES WILL CONTINUE THROUGH MID WEEK AS THE UPPER LEVEL SYSTEM
WEAKENS AND MOVES EAST NORTHEAST INTO THE CENTRAL PLAINS.
TEMPERATURES THROUGH MID WEEK WILL STAY ON THE COOL SIDE GIVEN THE
CLOUD COVER AND HIGH PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1225 PM CDT FRI MAY 15 2015
A WEAK SURFACE BOUNDARY WILL MOVE INTO EASTERN KANSAS BY LATE DAY
AND THIS WILL BE THE PRIMARY AREA OF FOCUS FOR ANY THUNDERSTORM
DEVELOPMENT BETWEEN 21Z FRIDAY AND 03Z SATURDAY. BASED ON THE
LATEST NAM THIS CONVECTION WILL STAY EAST OF ALL THREE TAF SITES
LATE THIS AFTERNOON AND EARLY TONIGHT. ANOTHER AREA OF CONVECTION
WILL DEVELOP BY EARLY THIS EVENING NEAR A TROUGH OF LOW PRESSURE
AT THE SURFACE OVER FAR EASTERN COLORADO. AS THESE STORMS IN
EASTERN COLORADO DEVELOP THEY WILL MOVE ACROSS WESTERN KANSAS
OVERNIGHT. AT THIS TIME THE BETTER CHANCE FOR CONVECTION WILL
OCCUR IN THE GCK AREA AROUND 06Z AND DDC AND HYS BETWEEN 09Z AND
12Z SATURDAY. AS THE CONVECTION MOVES EAST ACROSS WESTERN KANSAS
THE 12Z NAM BUFR SOUNDINGS INDICATE AN AREA OF LOW LEVEL MOISTURE
WILL INCREASE AS A SOUTH SOUTHEAST FLOW CONTINUES AT AROUND 15
KNOTS IN THE SURFACE TO 800MB LEVEL. GIVEN THE EXPECTED WIND
SPEEDS DENSE FOG IS NOT EXPECTED, HOWEVER LOW MVFR CEILINGS WILL
BE POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 64 78 53 80 / 60 60 50 0
GCK 61 80 51 78 / 50 30 30 0
EHA 55 76 49 77 / 40 30 20 0
LBL 62 80 51 80 / 50 30 30 0
HYS 64 77 54 78 / 50 60 50 0
P28 65 78 58 81 / 50 70 70 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1232 PM CDT Fri May 15 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 328 AM CDT FRI MAY 15 2015
A broad upper level low was slowly pushing east across southern CA
into southwest AZ. A minor lead upper level trough was lifting
northeast across west TX into western OK. This trough was providing
ascent for a complex of thunderstorms to develop across southwest OK
and west central TX early this morning. This lead upper level trough
will lift northeast into northeast OK and southeast KS later this
morning.
A lee surface trough was deepening across the central and southern
high plains. Southerly 850mb winds were advecting deeper moisture
northward across central and west central KS. The isentropic lift
was deep enough for elevated storms to develop across north central
KS. These storms were lifting north-northeast and may develop
eastward into the western counties of the CWA through the mid
morning hours. The stronger storms may produce small hail.
The GFS, RAP and WRF models show the minor wave over west central
TX/southwest OK lifting northeast and providing enough ascent along
with the deeper moisture return for scattered showers and
thunderstorms to develop across the southern counties of the CWA
during the late morning hours, and spreading northeast across east
central and northeast KS during the early afternoon hours. However
the NAM12 and HRRR show most of the the thunderstorms remaining
across the western and northern counties of the CWA this morning. I
went with chance pops across the western and southern counties this
morning with chance pops across the northeast counties this
afternoon. The vertical wind shear Today looks rather weak with only
20 to 30 KTS of SFC to 6KM effective shear across the CWA. Several
numerical models show 1500-2000 J/KG of MLCAPE developing across the
CWA, thus some of the thunderstorms this afternoon across the
northern half of the CWA may be strong to marginally severe this
afternoon. The primary hazards would be penny to quarter hail and 50
to 60 MPH wind gusts. Highs Today will range from the upper 70s to
lower 80s with mostly cloudy skies.
Tonight, the amplified upper level low will move east across UT and
the four corners region. A strong mid level jet max will move
northeast across NM into eastern CO. The minor H5 trough across
southeast KS and southwest MO this afternoon will move northeast
across central MO. The intense isentropic lift will develop
northward across the northern plains and upper Midwest. The CWA will
remain dry through most of the night. Stronger ascent across western
KS will cause elevated thunderstorms to develop late tonight. Some
of these thunderstorms may move into the western counties of the CWA
before day break. These elevated storms may be strong to severe with
the primary hazard being large hail. Overnight lows will only drop
into the mid 60s.
.LONG TERM...(Saturday through Thursday)
Issued at 328 AM CDT FRI MAY 15 2015
Forecast focus remains on impact of intense upper system that will
emerge into the Plains Saturday into Saturday night.
All models appear to be converging on the most likely scenario on
Saturday which is that severe thunderstorms will develop near and
east of a dryline from Dodge City north toward Goodland after 20z
Saturday. Storms will quickly intensify and race NE at 50 to 60
mph which could bring them into parts of central Kansas by 6pm to
7pm Saturday. If sufficient buoyancy/instability is present...low level
shear and deep shear of 20-30kts and 50-60kts respectively would
provide an environment capable of supporting all manner of hazards
with the storms.
The wild card in this forecast remains how much
morning elevated convection will develop across OK into KS. We
continue to see a signal from various models that some convection
will develop Saturday morning within the weakly capped warm
sector. This is plausible since forcing will increase in advance
of the upper trough so we could see some impact on destabilization
across parts of the area through midday if this occurs. This makes
the scenario on Saturday difficult to pin down at this point with
regard to magnitude of the risk. In any case...forcing...shear
profiles and potential instability suggest this has the potential
to be a high impact event for parts of the area Saturday evening
and will highlight that everyone needs to monitor this especially
given all of the outdoor activities this weekend.
The dry slot will work into the area Sunday with gusty southwest
winds and warm temps. Instability axis should shift east of the
area so will keep conds dry on Sunday pm. The cold front will
sweep through the area Sunday night bringing much cooler and drier
air into the area for Monday and Tues. Only a brief break before
the next wave will move into the region with more rain expected
for later Tues into early Thurs. Trends suggest that the
severe risk with this system should stay south of the area so look
for another widespread rain with isolated thunder with this system.
&&
.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1231 PM CDT FRI MAY 15 2015
Storms moving through the area this morning have pushed north of the
terminals, although some light rain may still be seen at TOP/FOE
within the next hour. Have left VCTS for this afternoon since there
is still a chance for some isolated storms. Ceilings should lift
behind this rain leaving VFR conditions at all sites until early
tomorrow morning. Between 06-08Z, sites are expected to drop to
MVFR, although IFR is possible for brief periods of time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS JACKSON KY
113 PM EDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1155 AM EDT FRI MAY 15 2015
AREA OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS IN EASTERN PART
OF FORECAST AREA WILL EXIT THE STATE BY 2 PM. HRRR CONTINUES TO
SHOW ISOLATED CONVECTION IN THE AFTERNOON...AND WILL CONTINUE WITH
THIS IN THE CURRENT FORECAST. HAVE UPDATED NDFD BASED ON LATEST
OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 926 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON LATEST RADAR AND
OBSERVATIONAL TRENDS. CURRENTLY A LINE OF SHOWERS WITH A FEW
THUNDERSTORMS IS MOVING ACROSS THE NW PART OF THE FORECAST AREA.
HAVE TIMED THIS ACROSS THE FORECAST AREA BASED ON CURRENT MOVEMENT
AND EXPECTED DIMINISHING TREND. HRRR SEEMS TO BE HANDING THIS
PRETTY GOOD...AND ONCE THIS MOVES OUT EXPECT A LULL BEFORE
ISOLATED CONVECTION BEGINS TO POP UP THIS AFTERNOON.
UPDATE ISSUED AT 715 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
RADAR TRENDS. ISOLATED SHOWERS AND EVEN A STRAY THUNDERSTORM AS
WELL AS SOME SPRINKLES WILL WORK ACROSS THE NORTHERN HALF TO TWO
OF THE AREA AS A SHORTWAVE WORKS THROUGH THE REGION. ADDITIONAL
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 15 2015
EARLY THIS MORNING...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS
CENTERED JUST EAST OF THE FLORIDA PENINSULA WITH SHORTWAVE
RIDGING NORTH ALONG THE EASTERN SEABOARD AND ANOTHER SHORTWAVE
RIDGE NORTHWEST INTO PARTS OF THE CENTRAL AND NORTHERN PLAINS. IN
BETWEEN...A SHORTWAVE TROUGH WAS WORKING TOWARD THE GREAT LAKES
AND ACROSS PARTS OF THE OH VALLEY AS IT MOVES AROUND THIS RIDGE.
FURTHER TO THE WEST...A TROUGH WAS MOVING INTO THE WESTERN CONUS.
THE SHORTWAVE WORKING ACROSS THE REGION AND THE ASSOCIATED SFC
SYSTEM WARM FRONT THAT IS GRADUALLY LIFTING NORTH ACROSS THE AREA
HAVE BROUGHT INCREASING MOISTURE THROUGH THE ENTIRE COLUMN TO THE
REGION. THIS HAS MAINLY BEEN REALIZED IN MID AND HIGH CLOUDS SO
FAR AND WARMER TEMPERATURES ATTM COMPARED TO 24 AND 48 HOURS AGO
DUE TO HIGHER SFC DEWPOINTS AND THE CLOUD COVER.
THE SHORTWAVE WILL MOVE INTO THE EASTERN GREAT LAKES AND MOVE
EAST OF THE AREA THIS MORNING...WITH SHORTWAVE RIDGING PROGGED TO
WORK ACROSS THE AREA FROM MIDDAY INTO THE EARLY EVENING. BEHIND
THE WARM FRONT...PW IS PROGGED TO BE IN THE 1.1 TO 1.3 INCH RANGE
OR SO. THE RIDGE AXIS IS EXPECTED TO MOVE EAST OF THE AREA
TONIGHT WITH THE REGION IN SOUTH TO SOUTHWEST FLOW ALOFT THROUGH
THE END OF THE PERIOD. WEAK SHORTWAVES WILL LIKELY MOVE ACROSS THE
AREA IN THIS FLOW AT TIMES FROM THIS EVENING OR TONIGHT THROUGH
THE END OF THE SHORT TERM PERIOD. THE MODEL CONSENSUS IS FOR ONE
OF THESE TO WORK ACROSS THE LOWER OH VALLEY REGION FROM LATE
TONIGHT INTO SATURDAY. WITH THE SOUTH TO SOUTHWEST FLOW CONTINUING
THROUGH THE COLUMN...MOISTURE WILL INCREASE FURTHER AND PW IS
PROGGED TO REACH THE 1.4 TO 1.6 OR 1.7 INCH RANGE ON SATURDAY.
SOME SPRINKLES OR LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH THE
REMAINDER OF THE OVERNIGHT THROUGH AROUND SUNRISE. ONCE THE
SHORTWAVE MOVES PAST THE AREA TODAY AND THE WARM FRONT LIFTS NORTH
TOWARD THE GREAT LAKES REGION...THERE WILL NOT BE ANY SUBSTANTIAL
TRIGGERS TODAY WITH 500MB HEIGHTS TRENDING UP THROUGH THE DAY.
DIFFERENTIAL HEATING ACROSS THE CUMBERLAND PLATEAU AND THE HIGHER
TERRAIN NEAR THE VA BORDER MAY HELP TO TRIGGER ANY INITIAL
DEVELOPMENT. THE AIRMASS IS EXPECTED TO BE RATHER MOIST AND
SOMEWHAT UNSTABLE BY AFTERNOON WHEN COUPLED WITH DAYTIME HEATING.
THE NAM GUIDANCE IS LIKELY TOO AGGRESSIVE WITH LOW LEVEL MOISTURE
AND CAPE FOR THIS AFTERNOON...BUT THE LESS AGGRESSIVE GFS HAS
CAPE OF AT LEAST 500 TO 1000 J/KG AND LI OF -2 TO -3C OR SO.
ISOLATED TO SCATTERED COVERAGE OF CONVECTION SEEMS PROBABLE...WITH
OUTFLOWS FROM INITIAL CONVECTION POSSIBLY BEING THE TRIGGER FOR
ADDITIONAL CONVECTION IN OTHER LOCATIONS.
A RELATIVE LULL IN COVERAGE OF CONVECTION IS ANTICIPATED FROM MID
TO LATE EVENING IN THE OVERNIGHT HOURS. HOWEVER...ONCE THE RIDGE
AXIS SHIFTS TO THE EAST AND AS A SHORTWAVE APPROACHES FROM THE
SOUTHWEST...ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE LATE
TONIGHT AND CONTINUING INTO SATURDAY. MODELS HAVE CAPE OF ABOUT
1000 TO 1500 J/KG OF SBCAPE ON SATURDAY WITH THIS GENERALLY BEING
OF THE TALL SKINNY CAPE VARIETY. WITH THE SHORTWAVE PASSING
THROUGH THE AREA AND DEWPOINTS EXPECTED TO BE SOLIDLY AT 60F OR
HIGHER...COVERAGE OF CONVECTION SHOULD BE MORE SUBSTANTIAL THAN ON
FRIDAY. THE PW WILL ALSO BE QUITE HIGH FOR MID MAY...AND WARM
CLOUD DEPTHS MAY ALSO APPROACH 10KFT OR MORE. WHAT CONVECTION THAT
DOES DEVELOP ON SATURDAY MAY BE RATHER EFFICIENT RAIN PRODUCERS
WITH QUITE SUBSTANTIAL RAIN RATES. THE STORM MOTIONS ARE PROGGED
TO BE NEARLY 20KTS...SO A LOCATION MAY NEED TO RECEIVE MULTIPLE
STORMS BEFORE HYDRO PROBLEMS MIGHT BEGIN. THE LAST FEW DAYS HAVE
BEEN DRY SO INITIAL STORMS MAY SERVE TO PRIME A LOCATION. ANY
LOCATIONS THAT RECEIVE MULTIPLE STORMS WOULD HAVE THE THREAT FOR
AT LEAST SOME MINOR FLOODING ISSUES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 401 AM EDT FRI MAY 15 2015
WE WILL BEGIN THE LONG TERM PERIOD WITH WARM AND MOIST ENVIRONMENT
AHEAD OF UPPER LEVEL LOW AND FRONT ACROSS THE PLAINS. GENERALLY
WEAK WAVES TRAVELING ALONG THE EDGE OF UPPER LEVEL RIDGE AND
AFTERNOON HEATING WILL HELP TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ONCE CONVECTIVE
TEMPS ARE REACHED. FORECAST SOUNDINGS AND TIME HEIGHT ANALYSIS
INDICATE MOIST COLUMN WITH PWATS IN THE AROUND 1.7 INCHES OR
HIGHER AT TIMES...SO ANY STORMS THAT FIRE HAVE THE POTENTIAL TO
PRODUCE HEAVY RAINFALL RATES SUNDAY INTO MONDAY. THE UPPER LEVEL
LOW ACROSS THE PLAINS WILL MOVE INTO THE GREAT LAKES AND BEGINS TO
FLATTEN OUT THE RIDGING IN PLACE AS WE MOVE INTO MONDAY. SURFACE
FRONT WILL ALSO APPROACH THE REGION MONDAY AND THIS COUPLED WITH
HEIGHT FALLS WILL BRING LIKELY POPS INTO THE REGION AHEAD OF
SURFACE BOUNDARY. KEEP THUNDER IN THE EVENING MONDAY BEFORE
TAPERING OFF INTO RAIN SHOWERS OVERNIGHT INTO TUESDAY MORNING.
RIGHT NOW IT LOOKS LIKE FRONT WILL COME THOUGH SOMETIME TUESDAY
MORNING OR EARLY AFTERNOON...WITH SLIGHTLY DIFFERING TIMING WITH
LONG RANGE MODELS. EITHER WAY THIS WILL USHER IN DRYER AND COOLER
AIR...AS SURFACE HIGH PRESSURE AND NORTHERLY FLOW BUILD INTO THE
REGION BY MID WEEK. WEDNESDAY WILL FEATURE DRY AND COOLER
CONDITIONS...WITH TEMPS TOPING OUT IN THE LOWER 70S. THIS WILL BE
SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. SLIGHT RETURN OF
MOISTURE BY LATE WEEK...BUT RIGHT NOW KEEP IN MOSTLY DRY THROUGH
THE REMAINDER OF THE LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 113 PM EDT FRI MAY 15 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD...BUT
ISOLATED SHOWERS AND THUNDERSTORMS WILL RESULT IN A FEW SPOTS
BRIEFLY DROPPING TO IFR THIS AFTERNOON. AN AREA OF SHOWERS AND
THUNDERSTORMS OVER FAR EASTERN KY AT 17Z WILL EXIT THE STATE BY
18Z. OTHER ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP AND AFFECT THE FORECAST AREA BETWEEN 18Z AND 22Z. THE AREA
MOST LIKELY TO BE AFFECTED BY THE ISOLATED THUNDERSTORMS WILL BE
THE SOUTHWEST PART OF THE FORECAST AREA. HAVE INCLUDED VCTS FOR
SME AND LOZ TO ACCOUNT FOR THIS. IT SHOULD BE NOTED THAT
CONFIDENCE IN LOCATION AND TIMING OF THUNDERSTORMS THIS AFTERNOON
REMAINS LOW. SOUTHWEST FLOW WILL RESULT IN INCREASING MOISTURE
ACROSS THE AREA INTO SATURDAY...AND AS A RESULT EXPECT COVERAGE OF
SHOWERS AND THUNDERSTORMS TO INCREASE SATURDAY AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JP
LONG TERM...DJ
AVIATION...SBH
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
534 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WEAK WARM FRONT APPROACHES FROM THE SOUTHWEST TONIGHT. THE WARM
FRONT WILL STALL OVER SOUTHERN NEW ENGLAND LATE TONIGHT AND
SATURDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT SATURDAY NIGHT
OVER THE GULF OF MAINE AND WILL GRADUALLY DRIFT OFF TO THE
SOUTHEAST ON SUNDAY. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHEAST SUNDAY NIGHT AND MONDAY. LOW PRESSURE CROSSING SOUTHERN
QUEBEC MONDAY NIGHT AND TUESDAY WILL DRIVE A COLD FRONT TOWARD THE
REGION. THE FRONT WILL CROSS THE REGION TUESDAY NIGHT. HIGH
PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATE...HAVE TO LOOK BACK ACROSS CENTRAL NY STATE TO FIND SHOWERS
REACHING THE GROUND AT THIS HOUR. HAVE DELAYED POP SLIGHTLY THIS
EVENING...AS MODEL FORECASTS KEEP US DRY UNTIL AFTER MIDNIGHT.
LATEST HRRR RUN SUPPORTS GLOBAL MODEL GUIDANCE...INDICATING THAT A
SUBTLE S/WV TROF ROUNDING THE RIDGE WILL FORCE A LOOSELY ORGANIZED
COMPLEX OF SHOWERS THRU THE SWRN ZONES LATE TONIGHT AND EARLY SAT.
PREVIOUS DISCUSSION...VERY DRY CONDITIONS WILL REMAIN IN THE
LOWER PORTIONS OF THE ATMOSPHERE LATE THIS AFTERNOON AND EARLY
THIS EVENING. WEAK WARM AIR ADVECTION WILL CONTINUE IN ASSOCIATION
WITH AN APPROACHING WARM FRONT. THE ATMOSPHERE WILL CONTINUE TO
GRADUALLY MOISTEN OVERNIGHT...EVENTUALLY SUFFICIENTLY TO BRING THE
CHANCE FOR A SHOWER TO THE REGION LATER TONIGHT.
IT WILL BE MILDER THAN LAST NIGHT DESPITE THE LOW DEW POINTS DUE
TO THE CLOUD COVER.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
THE GREATEST THREAT OF A SHOWER WILL MAINLY BE SATURDAY MORNING.
HOWEVER...ANY PRECIPITATION WILL BE LIGHT AND BRIEF.
A VERY LOW CHANCE SHOWER MAY LINTER INTO SATURDAY EVENING. THE 12Z
MESOSCALE MODEL SUITE SHOWS LAST OF THE SHOWERS TO MOVE EAST OF
OUR FORECAST AREA AROUND OR SHORTLY AFTER 06Z. IT WILL BE MILDER
ONCE AGAIN WITH OVERNIGHT LOWS MAINLY BETWEEN 45 AND 55 DEGREES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SHOWERS WILL BE COMING TO AN END OVER WESTERN MAINE SUNDAY MORNING
AS LOW PRESSURE AND WRAP AROUND MOISTURE MOVE OFFSHORE. HIGH
PRESSURE BUILDS IN FROM THE NORTH AND SHOULD MAKE FOR A NICE REST
OF THE DAY AS WELL AS WELL AS A SUNNY START FOR MONDAY. EVENTUALLY
CLOUDS WILL CREEP BACK IN LATER MONDAY AS ANOTHER FRONTAL SYSTEM
MOVES THROUGH MONDAY NIGHT AND TUESDAY... EXITING THE REGION
WEDNESDAY MORNING. CURRENTLY IT LOOKS LIKE THE BULK OF THE
PRECIPITATION WILL FALL DURING THE DAY TUESDAY. AFTER THIS THE
WEEK LOOKS VERY QUIET WEATHER WISE WITH A MOSTLY DRY FRONTAL
PASSAGE ON FRIDAY. THIS WILL JUST BE A WIND SHIFT FOR MUCH OF THE
REGION BUT IT MAY BRING A SHOWER OR TWO TO THE HIGHER TERRAIN.
TEMPERATURES WILL BE IN THE 70S TO NEAR 80 ON SUNDAY BEFORE
DROPPING BACK INTO THE 60S FOR MOST OF THE WORK WEEK. NEXT FRIDAY
WE WILL WARM BACK UP INTO THE 70S ONCE AGAIN. FROST REALLY ONLY
THREATENS IN THE NORTH WEDNESDAY NIGHT AS COLDER AIR FILTERS IN
BEHIND A FRONTAL PASSAGE.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TODAY THROUGH TONIGHT. MVFR/IFR CEILINGS
DEVELOPING SATURDAY.
LONG TERM...POSSIBLE MVFR WITH ANY REMAINING SHOWERS SUNDAY
MORNING. MVFR OR LOWER CEILINGS POSSIBLE MONDAY NIGHT INTO
TUESDAY IN SHOWERS. FOG LIKELY WEDNESDAY MORNING.
&&
.MARINE...
SHORT TERM...A WARM FRONT WILL BUILD TOWARDS THE COASTAL WATERS.
HOWEVER WINDS AND SEAS WILL REMAIN BELOW SCA THRESHOLDS.
LONG TERM...A COLD FRONT CROSSES THE WATERS TUESDAY NIGHT/
WEDNESDAY MORNING. WINDS SHOULD STAY BELOW ADVISORY LEVELS
THROUGH THE PERIOD AS WELL AS WAVES.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN IN THE 20S AND 30S THIS EVENING
BEFORE RECOVERING OVERNIGHT UNDER LIGHT WINDS. SHOWERS AND AN
INCREASING ONSHORE FLOW LATE TONIGHT AND SATURDAY WILL HELP TO
MOISTEN FUELS AND EASE FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
359 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST
THROUGH THE WEEKEND...BRINGING AN INCREASINGLY WARM AND MOIST
SOUTHERLY FLOW THROUGH THE WEEKEND. A COLD FRONT CROSSES THE REGION
TUESDAY...WITH SEASONABLE TEMPERATURES RETURNING THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
CURRENT SFC ANALYSIS PLACES HIGH PRESSURE JUST OFF THE MID ATLANTIC
COAST WITH A WARM FRONT LIFTING NORTH OF THE REGION. THIS HAS
ALLOWED FOR WARMER/MORE HUMID CONDITIONS TODAY COMPARED TO 24 HOURS
AGO. EARLIER SHORTWAVE HAS PUSHED OFFSHORE THIS AFTERNOON AS
UPSTREAM RIDGING BEGINS TO BUILD INTO THE ERN CONUS. LATEST REGIONAL
RADAR MOSAIC DEPICTS SCT SHOWERS/THUNDERSTORMS OVER THE CNTRL
APPALACHIANS...BUT THE LOCAL AREA REMAINS MOSTLY SUNNY-PARTLY
CLOUDY. CU FIELD OBSERVED ON VISIBLE SATELLITE OVER THE
PIEDMONT...BUT RAP MESOANALYSIS DEPICTS VERY LITTLE INSTABILITY AND
LIFT TO GO ALONG WITH A RATHER DRY AIRMASS. LATEST HRRR PUSHES THE
SHOWERS/THUNDERSTORMS OVER THE CNTRL APPALACHIANS EWD TOWARD THE
PIEDMONT...BUT QUICKLY DISSIPATING AS THEY MOVE OFF THE HIGHER
TERRAIN. THEREFORE...WILL MAINTAIN A DRY FORECAST THIS EVENING.
HIGH PRESSURE PUSHES FARTHER OFFSHORE TONIGHT WITH LIGHT RETURN FLOW
CONTINUING OVERNIGHT. SKIES AVG MOSTLY CLEAR-PARTLY CLOUDY. LOWS IN
THE UPPER 50S-LOW 60S. HAVE KEPT POPS SILENT TONIGHT...BUT WILL NEED
TO MONITOR UPSTREAM CONVECTION AS MODELS ATTEMPT TO SPREAD SHOWERS
SWD TOWARD THE MD ERN SHORE LATE TONIGHT. DRY/STABLE AIRMASS WILL
LIKELY PREVENT SHOWERS FROM MOVING INTO THE REGION.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
UPPER LEVEL RIDGE REMAINS ENTRENCHED OVER THE ERN CONUS THRU THE
SHORT TERM AS SFC HIGH PRESSURE LOCATES OFF THE SOUTHEAST COAST.
RETURN FLOW ON THE WRN PERIPHERY OF THE HIGH WILL RESULT IN A
STEADY/GRADUAL WARMING AND MOISTENING TREND THROUGH THE WEEKEND.
THETA-E ADVECTION AND TEMPS IN THE UPPER 80S WILL PRODUCE A
MARGINALLY UNSTABLE AIRMASS TO GO ALONG WITH INCREASING PWATS AND
STEEPENING LOW-LEVEL LAPSE RATES. BEST MOISTURE AND INSTABILITY
(MLCAPE VALUES 500-1000 J/KG) WILL BE ACROSS THE NW COUNTIES...SO
WILL MAINTAIN SLIGHT CHANCE-CHANCE POPS IN THAT REGION.
OTHERWISE...LACK OF APPRECIABLE FORCING AND MEAGER SHEAR TO GO ALONG
WITH WEAK FLOW SHOULD KEEP THE REMAINDER OF THE AREA DRY.
SHOWERS/THUNDERSTORMS DISSIPATE SAT EVENING WITH THE LOSS OF DAYTIME
HEATING/INSTABILITY. HIGHS SAT WARM INTO THE LOW-MID 80S INLAND AND
UPPER 70S TO LOW 80S ALONG THE COAST.
SHORTWAVE DIGS OFF THE NE COAST SAT NIGHT...PUSHING A BACKDOOR FRONT
SWD TOWARD THE LOCAL AREA. PERTURBATIONS (PERHAPS CONVECTIVELY
INDUCED) WILL ROUND THE RIDGE AND DROP TOWARD THE ERN SHORE. WILL
RETAIN SLIGHT CHANCE-CHANCE POPS NE COUNTIES SAT NIGHT. MILD LOWS
SAT NIGHT IN THE LOW-MID 60S.
EXPECT BETTER AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS SUN AND
MON AS A CLOSED UPPER LEVEL TROUGH FILLS AS IT EJECTS NE FROM THE
CENTRAL ROCKIES INTO THE NORTHERN PLAINS. THIS WILL DAMPEN THE UPPER
LEVEL RIDGE ACROSS THE REGION. ASSOCIATED COLD FRONT WILL REACH THE
OH VALLEY MON. PRESSURE FALLS ON THE LEE SIDE OF THE APPALACHIANS
WILL RESULT IN A SHARPENING LEE/THERMAL TROUGH OVER THE PIEDMONT
INTO CNTRL VA. THE TROUGH WILL PROVIDE BETTER LOW LEVEL CONVERGENCE
AND MODEST FORCING FOR ASCENT. BETTER UVM EXPECTED AS WEAK
PERTURBATIONS ROUND THE RIDGE. THE BACKDOOR FRONT WILL REMAIN JUST
NORTH OF THE LOCAL AREA SUN AFTERNOON...DROPPING OVER THE NE
COUNTIES SUN NIGHT. SHEAR REMAINS MARGINAL...BUT WARMER DEWPOINTS
AND BETTER INSTABILITY EXPECTED. HAVE MAINTAINED CHANCE-SOLID CHANCE
POPS ACROSS THE NRN HALF OF THE LOCAL AREA AND SLIGHT CHANCE-LOW END
CHANCE POPS SRN HALF SUN. HIGHS MID-UPPER 80S...WITH MID-UPPER 70S
ALONG THE COAST SUN. MILD SUN NIGHT (APPROACHING RECORD HI MINS)
WITH LOWS IN THE MID-UPPER 60S. WILL RETAIN SLIGHT CHANCE-CHANCE
POPS MON NIGHT AS THE FRONT DROPS INTO THE REGION. EVEN BETTER
FORCING/MOISTURE/INSTABILITY EXPECTED MON...RESULTING IN BETTER
CHANCES FOR AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS.
WARM AGAIN MON WITH HIGHS IN THE MID-UPPER 80S INLAND AND UPPER
70S/LOW 80S NEAR THE COAST. WITH MARGINAL SHEAR UNDER THE INFLUENCE
OF THE UPPER RIDGE...WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
HOWEVER...A FEW STRONG STORMS MAY PRODUCE GUSTY WINDS AND SMALL HAIL
SUN AND MON. IN ADDITION...PWATS AROUND +2 STD DEV AND VERY LIGHT
STEERING FLOW WILL PRODUCE LOCALLY HEAVY RAINFALL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED BEGINS WITH A WEAK AREA OF HIGH PRES CENTERED OVER
THE MID ATLANTIC KEEPING CONDITIONS UNSETTLED AND A GOOD CHANCE
FOR SHOWERS AND THUNDERSTORMS ESPECIALLY WITH AFTERNOON HEATING.
THE UPPER RIDGE AXIS BREAKS DOWN AND PUSHES EAST MONDAY SUCH THAT BY
TUESDAY THERE WILL BE A WEAK SHORTWAVE MOVING ACROSS THE REGION IN
THE WEST TO NORTHWEST UPPER FLOW. EXPECT ABOUT 30 KT OF SHEAR AND
DECENT INSTABILITY FROM HEATING AND UVM WITH THE UPPER SHORTWAVE.
MLCAPE LOOKS TO BE AROUND 1500 J/KG. THIS SHOULD BE ENOUGH TO GET
STORMS GOING WITH SOME ORGANIZATION. A COLD FRONT PUSHING THROUGH
LATE AFTERNOON / EVENING WILL ALSO HELP TO ORGANIZE STORMS. FOR
NOW HAVE GONE WITH A HIGH CHANCE FOR SHOWERS AND STORMS TUESDAY
BUT LATER FORECASTS WILL LIKELY RAISE POPS EVEN MORE.
THE COLD FRONT REACHES THE COAST TUESDAY EVENING. FOLLOWING THE
FRONT A SURGE OF COOLER AIR IS EXPECTED OVERNIGHT TUESDAY NIGHT INTO
EARLY WEDNESDAY AS HIGH PRES BUILDS IN FROM THE NW. EXPECT ONLY
SLIGHT CHANCE POPS OVERNIGHT TUESDAY AND NO POPS BY WED MORNING.
SLIGHTLY ABOVE NORMAL TEMPS MON AND TUE (LOW TO MID 80S INLAND
MID-UPPER 70S NEAR THE COAST) RETURN TO NEAR NORMAL WEDS- THU
(MID-UPPER 70S INLAND AND LOW 70S NEAR THE COAST. MILD LOWS MON
NIGHT (MID-UPPER 60S) COOL OFF INTO THE LOW-MID 50S INLAND TO
AROUND 60 NEAR THE COAST WEDS NIGHT-THU NIGHT.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SFC HIGH PRESSURE CENTERED JUST OFF THE COAST WITH LOW PRESSURE
MOVING THROUGH THE GREAT LAKES TONIGHT INTO SAT. HAVE MAINTAINED
VFR CONDITIONS THROUGH THE 18Z TAF PERIOD. ONSHORE NE FLOW AT KORF
ALTHOUGH AS SPEEDS INCREASE ALL AREAS TO ~10 KT WINDS SHOULD
BECOME SE OR S ALL AREAS AFTER 20Z. WINDS SHIFT TO THE S/SW
OVERNIGHT...WITH A CONTINUATION OF MAINLY MID/HIGH CLOUDS FROM
15-25 K FT. SOME OF THE GUIDANCE TRIES TO BRING LOW CIGS INTO THE
AREA AROUND 12Z SAT MORNING...THIS SEEMS UNLIKELY GIVEN A SW FLOW
AND ONLY A SHALLOW LAYER OF LOW LEVEL MOISTURE SO HAVE NOT
INCLUDED IN TAFS.
HIGH BECOMES NEARLY STATIONARY OFF THE MID ATLC CST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK...GENLY VFR CONDITIONS WILL PREVAIL.
WARMER AIRMASS/INCREASING MOISTURE COULD ALLOW FOR ISOLATED/WIDELY
SCATTERED TSTMS MAINLY IN THE LATE AFTN AND EVENING HRS (ESP
NORTH)...WITH A BIT MORE COVERAGE OF CONVECTION AT ALL SITES BY
MON/TUE.
&&
.MARINE...
RELATIVELY QUIET MARINE WX CONDS ON TAP FOR THE NEXT COUPLE DAYS.
THE SURFACE HIGH PRES HAS MOVED OFFSHORE THIS AFTN AND REMAINS
CENTERED WELL OFF THE MID ATLC/SE COAST. THIS HAS ALLOWED WINDS TO
BECOME SOUTHEAST THIS AFTERNOON AT 10 TO 15 KT. THE PRES GRADIENT
ALONG THE COAST AND BAY WILL TIGHTEN SLIGHTLY OVERNIGHT AS LOW
PRESSURE TRACKS WELL TO THE NORTH AND THE HIGH REMAINS OFFSHORE.
HAVE BUMPED UP WINDS TO 15 KT OVERNIGHT AND EARLY SATURDAY. SOME
GUSTS TO 18NKT WILL BE POSSIBLE EITHER SIDE OF DAYBREAK. THIS
WILL PUSH WAVES TO 2 FT ACROSS THE BAY AND WITH 2 TO 3 FT IN THE COASTAL
WATERS. WINDS BECOME MORE S TO SW SATURDAY AROUND 10 TO 15 KT BUT
GRADUALLY DECREASE TO 10 KT THROUGH THE AFTERNOON AS THE PRES
GRAD RELAXES. SUNDAY SLY WINDS CONTINUE AROUND 10 KT THEN BECOME
VARIABLE ON MONDAY AS WEAK LOW PRESSURE SETTLES IN OVER THE MID
ATLANTIC. THIS WILL ALSO RESULT INCREASING RAIN CHANCES MONDAY
WITH STORMS POSSIBLE TUESDAY AS A COLD FRONT PUSHES THROUGH. WIND
BECOME NW AROUND 15 KT WITH THE FRONTAL PASSAGE TUESDAY. SCA CONDS
ARE FORECAST TUE NIGHT INTO WEDNESDAY AS A SURGE OF COLD AIR
PUSHING IN BEHIND THE FRONT PUSHED NW WINDS TO 20 KT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...SAM
SHORT TERM...AJZ/SAM
LONG TERM...JAO
AVIATION...LKB
MARINE...MAS/JAO
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
355 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST
THROUGH THE WEEKEND...BRINGING AN INCREASINGLY WARM AND MOIST
SOUTHERLY FLOW THROUGH THE WEEKEND. A COLD FRONT CROSSES THE REGION
TUESDAY...WITH SEASONABLE TEMPERATURES RETURNING THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CURRENT SFC ANALYSIS PLACES HIGH PRESSURE JUST OFF THE MID ATLANTIC
COAST WITH A WARM FRONT LIFTING NORTH OF THE REGION. THIS HAS
ALLOWED FOR WARMER/MORE HUMID CONDITIONS TODAY COMPARED TO 24 HOURS
AGO. EARLIER SHORTWAVE HAS PUSHED OFFSHORE THIS AFTERNOON AS
UPSTREAM RIDGING BEGINS TO BUILD INTO THE ERN CONUS. LATEST REGIONAL
RADAR MOSAIC DEPICTS SCT SHOWERS/THUNDERSTORMS OVER THE CNTRL
APPALACHIANS...BUT THE LOCAL AREA REMAINS MOSTLY SUNNY-PARTLY
CLOUDY. CU FIELD OBSERVED ON VISIBLE SATELLITE OVER THE
PIEDMONT...BUT RAP MESOANALYSIS DEPICTS VERY LITTLE INSTABILITY AND
LIFT TO GO ALONG WITH A RATHER DRY AIRMASS. LATEST HRRR PUSHES THE
SHOWERS/THUNDERSTORMS OVER THE CNTRL APPALACHIANS EWD TOWARD THE
PIEDMONT...BUT QUICKLY DISSIPATING AS THEY MOVE OFF THE HIGHER
TERRAIN. THEREFORE...WILL MAINTAIN A DRY FORECAST THIS EVENING.
HIGH PRESSURE PUSHES FARTHER OFFSHORE TONIGHT WITH LIGHT RETURN FLOW
CONTINUING OVERNIGHT. SKIES AVG MOSTLY CLEAR-PARTLY CLOUDY. LOWS IN
THE UPPER 50S-LOW 60S. HAVE KEPT POPS SILENT TONIGHT...BUT WILL NEED
TO MONITOR UPSTREAM CONVECTION AS MODELS ATTEMPT TO SPREAD SHOWERS
SWD TOWARD THE MD ERN SHORE LATE TONIGHT. DRY/STABLE AIRMASS WILL
LIKELY PREVENT SHOWERS FROM MOVING INTO THE REGION.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL RIDGE REMAINS ENTRENCHED OVER THE ERN CONUS THRU THE
SHORT TERM AS SFC HIGH PRESSURE LOCATES OFF THE SOUTHEAST COAST.
RETURN FLOW ON THE WRN PERIPHERY OF THE HIGH WILL RESULT IN A
STEADY/GRADUAL WARMING AND MOISTENING TREND THROUGH THE WEEKEND.
THETA-E ADVECTION AND TEMPS IN THE UPPER 80S WILL PRODUCE A
MARGINALLY UNSTABLE AIRMASS TO GO ALONG WITH INCREASING PWATS AND
STEEPENING LOW-LEVEL LAPSE RATES. BEST MOISTURE AND INSTABILITY
(MLCAPE VALUES 500-1000 J/KG) WILL BE ACROSS THE NW COUNTIES...SO
WILL MAINTAIN SLIGHT CHANCE-CHANCE POPS IN THAT REGION.
OTHERWISE...LACK OF APPRECIABLE FORCING AND MEAGER SHEAR TO GO ALONG
WITH WEAK FLOW SHOULD KEEP THE REMAINDER OF THE AREA DRY.
SHOWERS/THUNDERSTORMS DISSIPATE SAT EVENING WITH THE LOSS OF DAYTIME
HEATING/INSTABILITY. HIGHS SAT WARM INTO THE LOW-MID 80S INLAND AND
UPPER 70S TO LOW 80S ALONG THE COAST.
SHORTWAVE DIGS OFF THE NE COAST SAT NIGHT...PUSHING A BACKDOOR FRONT
SWD TOWARD THE LOCAL AREA. PERTURBATIONS (PERHAPS CONVECTIVELY
INDUCED) WILL ROUND THE RIDGE AND DROP TOWARD THE ERN SHORE. WILL
RETAIN SLIGHT CHANCE-CHANCE POPS NE COUNTIES SAT NIGHT. MILD LOWS
SAT NIGHT IN THE LOW-MID 60S.
EXPECT BETTER AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS SUN AND
MON AS A CLOSED UPPER LEVEL TROUGH FILLS AS IT EJECTS NE FROM THE
CENTRAL ROCKIES INTO THE NORTHERN PLAINS. THIS WILL DAMPEN THE UPPER
LEVEL RIDGE ACROSS THE REGION. ASSOCIATED COLD FRONT WILL REACH THE
OH VALLEY MON. PRESSURE FALLS ON THE LEE SIDE OF THE APPALACHIANS
WILL RESULT IN A SHARPENING LEE/THERMAL TROUGH OVER THE PIEDMONT
INTO CNTRL VA. THE TROUGH WILL PROVIDE BETTER LOW LEVEL CONVERGENCE
AND MODEST FORCING FOR ASCENT. BETTER UVM EXPECTED AS WEAK
PERTURBATIONS ROUND THE RIDGE. THE BACKDOOR FRONT WILL REMAIN JUST
NORTH OF THE LOCAL AREA SUN AFTERNOON...DROPPING OVER THE NE
COUNTIES SUN NIGHT. SHEAR REMAINS MARGINAL...BUT WARMER DEWPOINTS
AND BETTER INSTABILITY EXPECTED. HAVE MAINTAINED CHANCE-SOLID CHANCE
POPS ACROSS THE NRN HALF OF THE LOCAL AREA AND SLIGHT CHANCE-LOW END
CHANCE POPS SRN HALF SUN. HIGHS MID-UPPER 80S...WITH MID-UPPER 70S
ALONG THE COAST SUN. MILD SUN NIGHT (APPROACHING RECORD HI MINS)
WITH LOWS IN THE MID-UPPER 60S. WILL RETAIN SLIGHT CHANCE-CHANCE
POPS MON NIGHT AS THE FRONT DROPS INTO THE REGION. EVEN BETTER
FORCING/MOISTURE/INSTABILITY EXPECTED MON...RESULTING IN BETTER
CHANCES FOR AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS.
WARM AGAIN MON WITH HIGHS IN THE MID-UPPER 80S INLAND AND UPPER
70S/LOW 80S NEAR THE COAST. WITH MARGINAL SHEAR UNDER THE INFLUENCE
OF THE UPPER RIDGE...WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
HOWEVER...A FEW STRONG STORMS MAY PRODUCE GUSTY WINDS AND SMALL HAIL
SUN AND MON. IN ADDITION...PWATS AROUND +2 STD DEV AND VERY LIGHT
STEERING FLOW WILL PRODUCE LOCALLY HEAVY RAINFALL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
VERY LITTLE CHANGE IS EXPECTED WITH RESPECT TO THE LONGWAVE
PATTERN TONIGHT THROUGH SUNDAY. RETURN FLOW ON THE WRN PERIPHERY
OF THE HIGH WILL RESULT IN A STEADY/GRADUAL WARMING AND MOISTENING
TREND THROUGH THE WEEKEND. PW VALUES RISE AND MID-LEVEL LAPSE
RATES STEEPEN ENOUGH TO ALLOW FOR A SLIGHT CHC/LOW CHC OF
-SHRA/TSRA SATURDAY AFTERNOON/EVENING FOR FAR NW TIER OF PIEDMONT
COUNTIES. OTHERWISE...LITTLE FORCING AND MEAGER SHEAR UNDERNEATH
THE UPPER RIDGE SHOULD KEEP THE REMAINDER OF THE AREA DRY AND
PARTLY TO MOSTLY SUNNY FOR SATURDAY. ANY -SHRA/TSRA SHOULD
DISSIPATE QUICKLY SATURDAY EVENING. HIGHS SATURDAY WARM INTO THE
LOW/MID 80S INLAND WITH UPPER 70S LOW 80S ALONG THE IMMEDIATE
COAST. LOWS TONIGHT SHOULD BE IN THE UPPER 50S/LOW 60S...WITH
LOW/MID 60S SATURDAY NIGHT.
EXPECT A BIT MORE AREAL COVERAGE OF SHRA/TSRA BY SUNDAY AFTERNOON
AND EVENING. A CLOSED UPPER LEVEL TROUGH WILL FILL AS IT EJECTS NE
FROM THE CENTRAL ROCKIES INTO THE NORTHERN PLAINS SUNDAY INTO
SUNDAY NIGHT...WHICH WILL DAMPEN THE UPPER RIDGE ACROSS THE
CENTRAL APPALACHIANS AND NRN MID ATLANTIC. A WEAK LEE TROUGH WILL
DEVELOP DOWNSTREAM ACROSS THE BLUE RIDGE BY LATER
SUNDAY...PROVIDING SOME OW-LEVEL CONVERGENCE AND MODEST FORCING
FOR ASCENT. HIGHEST POPS REMAIN ORIENTED ACROSS THE NORTHWESTERN
THIRD OF THE AREA...ROUGHLY NW OF A LINE FROM FVX-RIC-WAL. MLCAPE
IS MARGINALLY UNSTABLE ACROSS THE NORTH (~1000 J/KG)...BUT SHEAR
REMAINS MINIMAL SO SEVERE STORMS ARE NOT ANTICIPATED. THOUGH WITH
PW RAMPING AOA 1.5" AND WITH VERY LIGHT STEERING FLOW...LOCALLY
HEAVY RAINFALL WOULD APPEAR TO BE THE PRIMARY HAZARD WITH ANY
STORMS. WARMER AND MODERATELY HUMID SUNDAY WITH HIGHS IN THE MID
TO UPPER 80S INLAND...WITH UPPER 70S TO MID 80S ALONG THE
IMMEDIATE COAST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE EXTENDED BEGINS WITH A WEAK AREA OF HIGH PRES CENTERED OVER
THE MID ATLANTIC KEEPING CONDITIONS UNSETTLED AND A GOOD CHANCE
FOR SHOWERS AND THUNDERSTORMS ESPECIALLY WITH AFTERNOON HEATING.
THE UPPER RIDGE AXIS BREAKS DOWN AND PUSHES EAST MONDAY SUCH THAT BY
TUESDAY THERE WILL BE A WEAK SHORTWAVE MOVING ACROSS THE REGION IN
THE WEST TO NORTHWEST UPPER FLOW. EXPECT ABOUT 30 KT OF SHEAR AND
DECENT INSTABILITY FROM HEATING AND UVM WITH THE UPPER SHORTWAVE.
MLCAPE LOOKS TO BE AROUND 1500 J/KG. THIS SHOULD BE ENOUGH TO GET
STORMS GOING WITH SOME ORGANIZATION. A COLD FRONT PUSHING THROUGH
LATE AFTERNOON / EVENING WILL ALSO HELP TO ORGANIZE STORMS. FOR
NOW HAVE GONE WITH A HIGH CHANCE FOR SHOWERS AND STORMS TUESDAY
BUT LATER FORECASTS WILL LIKELY RAISE POPS EVEN MORE.
THE COLD FRONT REACHES THE COAST TUESDAY EVENING. FOLLOWING THE
FRONT A SURGE OF COOLER AIR IS EXPECTED OVERNIGHT TUESDAY NIGHT INTO
EARLY WEDNESDAY AS HIGH PRES BUILDS IN FROM THE NW. EXPECT ONLY
SLIGHT CHANCE POPS OVERNIGHT TUESDAY AND NO POPS BY WED MORNING.
SLIGHTLY ABOVE NORMAL TEMPS MON AND TUE (LOW TO MID 80S INLAND
MID-UPPER 70S NEAR THE COAST) RETURN TO NEAR NORMAL WEDS- THU
(MID-UPPER 70S INLAND AND LOW 70S NEAR THE COAST. MILD LOWS MON
NIGHT (MID-UPPER 60S) COOL OFF INTO THE LOW-MID 50S INLAND TO
AROUND 60 NEAR THE COAST WEDS NIGHT-THU NIGHT.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SFC HIGH PRESSURE CENTERED JUST OFF THE COAST WITH LOW PRESSURE
MOVING THROUGH THE GREAT LAKES TONIGHT INTO SAT. HAVE MAINTAINED
VFR CONDITIONS THROUGH THE 18Z TAF PERIOD. ONSHORE NE FLOW AT KORF
ALTHOUGH AS SPEEDS INCREASE ALL AREAS TO ~10 KT WINDS SHOULD
BECOME SE OR S ALL AREAS AFTER 20Z. WINDS SHIFT TO THE S/SW
OVERNIGHT...WITH A CONTINUATION OF MAINLY MID/HIGH CLOUDS FROM
15-25 K FT. SOME OF THE GUIDANCE TRIES TO BRING LOW CIGS INTO THE
AREA AROUND 12Z SAT MORNING...THIS SEEMS UNLIKELY GIVEN A SW FLOW
AND ONLY A SHALLOW LAYER OF LOW LEVEL MOISTURE SO HAVE NOT
INCLUDED IN TAFS.
HIGH BECOMES NEARLY STATIONARY OFF THE MID ATLC CST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK...GENLY VFR CONDITIONS WILL PREVAIL.
WARMER AIRMASS/INCREASING MOISTURE COULD ALLOW FOR ISOLATED/WIDELY
SCATTERED TSTMS MAINLY IN THE LATE AFTN AND EVENING HRS (ESP
NORTH)...WITH A BIT MORE COVERAGE OF CONVECTION AT ALL SITES BY
MON/TUE.
&&
.MARINE...
RELATIVELY QUIET MARINE WX CONDS ON TAP FOR THE NEXT COUPLE DAYS.
THE SURFACE HIGH PRES HAS MOVED OFFSHORE THIS AFTN AND REMAINS
CENTERED WELL OFF THE MID ATLC/SE COAST. THIS HAS ALLOWED WINDS TO
BECOME SOUTHEAST THIS AFTERNOON AT 10 TO 15 KT. THE PRES GRADIENT
ALONG THE COAST AND BAY WILL TIGHTEN SLIGHTLY OVERNIGHT AS LOW
PRESSURE TRACKS WELL TO THE NORTH AND THE HIGH REMAINS OFFSHORE.
HAVE BUMPED UP WINDS TO 15 KT OVERNIGHT AND EARLY SATURDAY. SOME
GUSTS TO 18NKT WILL BE POSSIBLE EITHER SIDE OF DAYBREAK. THIS
WILL PUSH WAVES TO 2 FT ACROSS THE BAY AND WITH 2 TO 3 FT IN THE COASTAL
WATERS. WINDS BECOME MORE S TO SW SATURDAY AROUND 10 TO 15 KT BUT
GRADUALLY DECREASE TO 10 KT THROUGH THE AFTERNOON AS THE PRES
GRAD RELAXES. SUNDAY SLY WINDS CONTINUE AROUND 10 KT THEN BECOME
VARIABLE ON MONDAY AS WEAK LOW PRESSURE SETTLES IN OVER THE MID
ATLANTIC. THIS WILL ALSO RESULT INCREASING RAIN CHANCES MONDAY
WITH STORMS POSSIBLE TUESDAY AS A COLD FRONT PUSHES THROUGH. WIND
BECOME NW AROUND 15 KT WITH THE FRONTAL PASSAGE TUESDAY. SCA CONDS
ARE FORECAST TUE NIGHT INTO WEDNESDAY AS A SURGE OF COLD AIR
PUSHING IN BEHIND THE FRONT PUSHED NW WINDS TO 20 KT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/MAM
NEAR TERM...AJZ/SAM
SHORT TERM...AJZ/MAM
LONG TERM...JAO
AVIATION...LKB
MARINE...MAS/JAO
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
235 PM CDT Fri May 15 2015
...Unsettled Weather This Weekend Followed By Cooler Weather Again
Early Next Week...
.SHORT TERM...(This Evening through Saturday)
Issued at 222 PM CDT FRI MAY 15 2015
A weak impulse is currently moving across the Missouri Ozarks and
lifting northeastward. Scattered convection has developed ahead of
the impulse across central Missouri and the eastern Ozarks where
instability is better. This convection will continue to move
northward. There appears to be a little subsidence behind the
exiting upper level impulse. Additional isolated to widely scattered
convection is possible elsewhere through the evening hours where the
sun is able to add some instability but it will be limited. Short range
models like the HRRR and RUC13 keep most of the convection
redevelopment towards central Missouri this evening.
Later this evening...for the most part the weather should be fairly
quiet. Will mention the possibility of some patchy fog near large
lakes and river valleys by sunrise in the morning. Forecast cape for
tomorrow approach 2500 J/KG but the deep shear will be limited
around 20 to 25 knots for most of the day over the Ozarks. The
better dynamics will be just to our west across Kansas and Oklahoma
for severe convection. Scattered convection will develop around the
Missouri Ozarks by midday to afternoon on Saturday with the best
potential over south central Missouri.
Models indicate that the leftover severe convection that develops
across Kansas and Oklahoma will move into southeast Kansas and
extreme western Missouri late Saturday evening and overnight. There
is a slight risk for severe weather Saturday evening for these areas
with the main threat being damaging wind gusts and large hail.
MUCape will be between 1500 to 2000 J/KG with Bulk shear values
increasing to 40 knots by Saturday evening over southeast Kansas
and western Missouri. Line segments and clusters of convection is
expected moving eastward from Kansas and Oklahoma into the western
Missouri Ozarks. Total QPF this weekend is expected on average
between 0.5 to 1.0 of an inch.
.LONG TERM...(Sunday through Friday)
Issued at 222 PM CDT FRI MAY 15 2015
The main upper level support and energy moves away from the area on
Sunday and Sunday night. Models indicate the best potential for
additional convection develop on Sunday afternoon and evening will be
south and east of I-44 across south central Missouri. There is a
very limited potential for a couple strong storms over south central
Missouri Sunday evening. A cold front finally makes some progress
into the area by Monday. There will be a chance for showers and
storms across south central Missouri before the front clears through
the area.
Cool and drier air will move in for Monday night through Tuesday
evening. Temperatures will be below average. The weather pattern
becomes unsettled again by the middle and end of next week.
Another broad trough develops across the western U.S. and weak
shortwaves and impulses will move across the central Plains and
Midwest starting Wednesday through Friday with scattered rain
chances and thunderstorms.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1240 PM CDT FRI MAY 15 2015
For the KSGF, KJLN, and KBBG TAFS: Scattered showers and storms
will be possible across the area this afternoon into early this
evening. Storms are expected to develop, but with the scattered
nature of this activity covering the potions in the TAFS with
Tempo groups since they will not be widespread.
The convection should push east of the area overnight with mainly
dry conditions expected. MVFR ceilings will be possible early
Saturday morning with light fog possible at the KBBG TAF site.
Additional scattered showers and storms will be possible Saturday
morning but the better chances should remain south and west of the
area until the afternoon hours which is beyond this TAF period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Wise
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
115 PM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CDT FRI MAY 15 2015
TODAY AND TONIGHT... A WEAK COLD FRONT HAS DROPPED SOUTH TO JUST
NORTH OF INTERSTATE 80 PER SFC OBS AND RTMA ANALYSIS. EAST WINDS ARE
UNDERWAY IN THE PLATTE VALLEY. STRATUS NORTH OF THE FRONT ACROSS NRN
NEB COULD SPREAD SOUTH TO NEAR THEDFORD AND PERHAPS AS FAR SOUTH AS
BROKEN BOW BY MORNING. THE THUNDERSTORMS UNDERWAY ACROSS SWRN NEB
THIS MORNING SHOULD MOVE UP AND OVER THE FRONT PRODUCING RAIN COOLED
AIR WHICH WOULD KEEP THE FRONT IN OR NEAR THE PLATTE VALLEY UNTIL
AFTERNOON. THIS AFTERNOON...FRONT COULD BEGIN TO MOVE NORTH SLOWLY.
THE MODEL CONSENSUS SHOWS THE FRONT LIFTING RAPIDLY NORTH TONIGHT.
THE BEST GUESS ON THE SEVERE WEATHER IS A BIT OPTIMISTIC. STRONG
WINDS ALOFT...40 TO 50 KT AT 500 MB AND 60 KT AT 300 MB SHOULD MOVE
INTO SWRN NEB AROUND 18Z AND FIRE CONVECTION ON A WARM FRONT DRAPED
ACROSS THE SRN SANDHILLS BY 21Z...PERHAPS ALIGNED E-SE TOWARD
LEXINGTON. THE RAP SHOWS LARGE SCALE LIFT AT THE SAME TIME EMANATING
FROM A LONG WAVE TROF OVER THE SWRN U.S.
TORNADO PARAMETERS LOOK REASONABLY GOOD WITH NICELY CURVED
HODOGRAPHS NEAR THE FRONT FOR SEVERAL HOURS DURING THE AFTN. THIS
PRODUCES 0-3KM HELICITY OVER 400 M2/S2 AND WHEN COMBINED WITH THE
INSTABILITY THE ENERGY HELICITY INDEX IS OVER 4 ALONG THE FRONT.
THUS A TORNADO OR TWO COULD FORM. WINDS ALOFT ARE A BIT LINEAR AND
CONRAD CONTINUES TO SUGGEST SPLITTING DOMINANT RIGHT MOVING
SUPERCELLS.
NOTE THE RAP...THE FAVORED MODEL...MOVES THE FRONT VERY LITTLE TODAY
WHICH COULD ALLOW FOR SEVERE STORMS TO RIDE UP AND OVER THE FRONT
AND BECOME MORE OF A HAIL THREAT.
SPC SUGGESTED STORM ACTIVITY WOULD WEAKEN THIS EVENING AND IT IS
POSSIBLE THE LARGE SCALE LIFT AND UPPER LEVEL SUPPORT COULD DO THE
SAME CARRYING THE BULK OF THE STORM ACTION INTO NRN NEB BY 00Z AS
SUGGESTED BY THE MODEL CONSENSUS.
THE FORECAST USES A BLEND OF THE RAP...NAM...GEMREG...ARW AND NMM.
THE OTHER MODELS WERE TOO COARSE RESOLUTION TO CAPTURE THE SPIRIT OF
THE EVENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CDT FRI MAY 15 2015
DETERMINISTIC MODELS AND ENSEMBLE MEANS CONTINUE TO ADVERTISE A
PERSISTENT UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT
WEEK. BLOCKY SETUP ALONG THE WEST COAST INTO THE CENTRAL ROCKIES
WITH A HIGH AMPLITUDE RIDGE OVER WESTERN CANADA OVER THE TOP OF A
BROAD TROUGH EXTENDING SOUTHWARD TOWARD THE BAJA OF CALIFORNIA.
RIDGE TO THE EAST WILL BEGIN TO FLATTEN INTO EARLY NEXT WEEK AS A
LOW BUILDS INTO SOUTHEAST CANADA. THE MEAN UPPER LEVEL FLOW OVER THE
CENTRAL PLAINS REMAINS OUT OF THE SOUTHWEST THROUGH THE LONG RANGE
PERIOD AND IN THE CROSSHAIRS OF SEVERAL SHORTWAVE PERTURBATIONS
ASSOCIATED WITH THE WESTERN CONUS TROUGH.
ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE AGAIN ON SATURDAY AS
STRONG PV MAX AND UPPER LEVEL JET STREAK EJECT NORTHEAST OUT OF THE
FOUR CORNERS REGION. LEE SIDE LOW AND ASSOCIATED PACIFIC FRONT MAKE
LITTLE EASTWARD PROGRESSION TOWARD THE EASTERN NEBRASKA PANHANDLE BY
THE BEGINNING OF THE PERIOD. SCATTERED ELEVATED STORMS LEFTOVER FROM
FRIDAY NIGHT SHOULD BE PUSHING NORTH AND EAST OF THE CWA DURING THE
MORNING HOURS...AIDED BY A VEERING LLJ. CONVECTIVE INITIATION IS
LIKELY ONCE AGAIN BY MID AFTERNOON IN AN INCREASINGLY UNSTABLE WARM
SECTOR EAST OF THE PACIFIC FRONT. MODELS ARE STRUGGLING WITH THEIR
HANDLING OF WARM SECTOR RECOVERY...AND ANY CLOUD COVER WILL HAVE A
SIGNIFICANT IMPACT ON THE DEGREE OF DESTABILIZATION. HOWEVER SEVERE
STORMS WILL STILL BE POSSIBLE GIVEN THE STRONG FORCING FOR ASCENT
AND FAVORABLE DEEP LAYER SHEAR. WIND PROFILES CONTINUE TO LOOK
FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...FAVORING
UPSCALE GROWTH AS THE THUNDERSTORM ACTIVITY EVOLVES THROUGH THE
AFTERNOON AND EVENING. LARGE HAIL...DAMAGING WINDS WILL BE THE
PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL ALSO NEED TO BE CLOSELY
WATCHED AS SOME AREAS MAY EXPERIENCE SEVERAL ROUNDS/TRAINING
THUNDERSTORMS.
SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY ACROSS THE NORTHERN
TIER OF THE CWA. LOW LEVEL MOISTURE WRAPS AROUND THE BACKSIDE OF THE
SFC LOW NOW OVER THE DAKOTAS AND BACK INTO NEBRASKA...UNDERNEATH
ANOMALOUSLY COLD AIR ALOFT ASSOCIATED WITH THE PASSING OF THE
UPPER LEVEL LOW. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS
EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS.
THE MIDDLE OF THE WEEK LOOKS COOL AND WET AS ANOTHER UPPER LEVEL
SHORTWAVE TROUGH PIVOTS NORTHEAST THROUGH THE EASTERN ROCKIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 115 PM CDT FRI MAY 15 2015
MOST OF THE AREA BECOMING VFR AS SHOWERS LIFT INTO S DAKOTA. A FEW
POCKETS OF MVFR/IFR CIGS...MAINLY ACROSS NORTHERN NEBRASKA. THIS
EVENING THUNDERSTORMS ARE LIKELY TO DEVELOP AND LIFT NORTHEAST
ACROSS THE AREA. DEVELOPMENT NEAR KLBF AND ONLY INCLUDED VCTS FOR
NOW AND WILL AMEND AS DEVELOPMENT OCCURS. HIGHER CONFIDENCE OF
THUNDERSTORMS ACROSS NORTHERN NEBRASKA AND INCLUDED A TEMPO FOR
KVTN. ALSO GOING TO SEE INCREASING SOUTHEASTERLY WINDS FOR THE
AFTERNOON.
AFTER STORMS LIFT NORTH OVERNIGHT EXPECT A LULL IN THE ACTIVITY
INTO TOMORROW MORNING. HOWEVER SOME AREAS OF STRATUS COULD
DEVELOP AND IMPACT THE TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS ELKO NV
342 PM PDT FRI MAY 15 2015
.SYNOPSIS...A PACIFIC STORM SYSTEM WILL BRING A COOL AND RAINY
SATURDAY TO NORTHEASTERN NEVADA. BENEFICIAL VALLEY RAIN AND
MOUNTAIN SNOW SHOWERS WILL CONTINUE THROUGH SUNDAY. THE MUCH
NEEDED WET PATTERN WILL CONTINUE THROUGH NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SUNDAY. EXPECT THE UNSETTLED WEATHER
PATTERN TO CONTINUE THROUGH THE SHORT TERM PERIOD.
INSTABILITY IS MEAGER TODAY...BUT EARLIER BREAKS IN THE CLOUDS
ALLOWED FROM SOME POCKETS OF HIGHER INSTABILITY TO DEVELOP.
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE
EVENING...BUT WILL TRANSITION TO ALL RAIN SHOWERS BY 06Z. SNOW
LEVELS WILL REMAIN HIGH. HAD A REPORT OF SNOW AROUND 7500FT IN THE
RUBY MTNS...BUT NO ACCUMULATION. ACCUMULATING SNOW WILL STAY
MOSTLY ABOVE THAT. WRAP AROUND PRECIP WILL INCREASE TONIGHT ACROSS
NORTHEASTERN NV AND PERSIST INTO SATURDAY. HRRR SHOWS THIS NICELY
AND AGREES WITH THE GFS/EURO ON THE PLACEMENT/MOVEMENT OF THIS
PRECIP.
SATURDAY AND SUNDAY....EXPECT ANOTHER ROUND OF SHOWERS AND
ISOLATED THUNDERSTORMS...WITH THE MAJORITY OF THE ACTION IN
EASTERN NV. AS THE LOW PULLS AWAY...WRAP AROUND SHOWERS WILL
CONTINUE TO SPREAD ACROSS NORTHEASTERN NEVADA. FORECAST MODELS
HINT AT SOME HEAVIER SHOWERS THROUGH SATURDAY EVENING. MOST PLACES
WILL SEE AROUND 0.25 INCHES...WITH SOME LOCALIZED LOCATIONS IN NE
NV SEEING UP TO AN INCH OF LIQUID. BY SUNDAY...THE NEXT SYSTEM
STARTS TO IMPACT THE WEATHER IN OUR CWA. WITH RESIDUAL MOISTURE
AND THE CONTINUED INCREASING MOISTURE...THUNDERSTORMS MAY BECOME
MORE WIDESPREAD.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY. THE MODELS ARE IN GOOD
AGREEMENT THAT A PERIOD OF WET WEATHER IS IN STORE FOR THE GREAT
BASIN DURING THIS FORECAST PERIOD. A COUPLE OF CLOSED UPPER LOWS
WILL MOVE ACROSS THE GREAT BASIN DURING THE PERIOD BRINGING SHOWERS
AND THUNDERSTORMS. THE FIRST UPPER LOW WILL MOVE ONTO THE CENTRAL CA
COAST SUNDAY NIGHT THEN SLOWLY MEANDER EASTWARD INTO NV BY TUESDAY
AND DEPART TO THE EAST BY EARLY WEDNESDAY. A SECOND UPPER LOW WILL
BE QUICK ON ITS HEELS MOVING INTO CENTRAL CA ON WEDNESDAY ENDING UP
OVER NV BY FRIDAY.
&&
.AVIATION...A LOW PRESSURE SYSTEM MOVING ACROSS THE REGION WILL
BRING SHOWERS AND ISOLATED THUNDERSTORMS DURING THE NEXT 24 HOURS.
CONDITIONS WILL GENERALLY REMAIN VFR, BUT OCCASIONAL MVFR
CONDITIONS WILL OCCUR UNDER THE HEAVIER SHOWERS.
&&
.FIRE WEATHER...CONTINUED STORMINESS WILL PERSIST THROUGH THE NEXT
WEEK OR SO. EXPECT AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS
EACH AFTERNOON. COVERAGE OF THUNDERSTORMS MAY INCREASE INTO EARLY
NEXT WEEK...BUT ALL STORMS WILL REMAIN WET. RH RECOVERIES EACH
NIGH/MORNING WILL BE GOOD...AS ABUNDANT MOISTURE/PRECIP
CONTINUES. EXPECT ROUNDS OF HIGH ELEVATION SNOW ABOVE 7000 FT
THROUGH TOMORROW...RISING TO ABOVE 8000-8500 FT NEXT WEEK.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
94/91/91
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
110 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 954 AM CDT FRI MAY 15 2015
HIGH PRESSURE NOSING INTO NORTHEAST NORTH DAKOTA ALONG WITH A
DRIER AIRMASS (CLEAR SKY). THE MAIN CHALLENGE FOR TODAY WILL BE
THE DEGREE OF CLEARING AND THIS AFFECT ON MAX TEMPS. HIGH PRESSURE
CONTINUE TO BUILD INTO THE REGION TODAY...ALTHOUGH WITH HIGHER
BASED CLOUDS ADVECTING INTO THE REGION FROM THE SOUTH...AREAS
ACROSS SOUTHEAST ND AND WC MN MAY NEVER TOTALLY BECOME CLEAR. WITH
THE CURRENT CLEAR SKY ACROSS THE NE ND DID RAISE MAX TEMPS A
COUPLE DEGREES HERE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
MODELS IN GOOD AGREEMENT FOR TODAY WITH SFC HIGH PRESSURE TO THE
NW BRINGING A TIGHTENING OF THE SFC PRESSURE GRADIENT. THIS IS
ALLOWING DRIER AIR AND CLEARING SKIES TO WORK INTO THE DEVILS LAKE
BASIN. AHEAD OF THE THIS FEATURE IS A SATURATED AIRMASS WITH
AREAS OF FOG AND SOME PATCHY DRIZZLE OCCURRING AS DEWPOINTS ARE IN
THE UPR 40S. WILL KEEP THE DRIZZLE FOG MENTION THRU 9AM.
AS THE MORNING TURNS INTO MID DAY UNCERTAINTY EXISTS IN THE
SOUTHWARD EXTENT OF THE CLEARING AND CLOUD COVER. RECENT THE RAP
AND HRRR MESOSCALE MODEL RUNS BRING THE CLEARING TO GFK BUT NOT
AS FAR SOUTH AS FARGO.
TONIGHT ATTENTION TURNS TO STRONG MOISTURE AND WARM AIR ADVECTION
ESCORTED NORTHWARD BY 30 TO 40 KT 850MB SOUTHERLY JET WHICH WILL
CONTINUE THROUGH THE DAY SATURDAY. AMOUNT OF CLOUD COVER WILL
DETERMINE SFC TEMPS AND AMOUNT OF INSTABILITY THAT DEVELOPS AHEAD
OF A DEVELOPING SFC LOW ACROSS THE WESTERN DAKOTAS. MODEL TRENDS
ARE SLOWER WITH THE SYSTEM BRINGING THE SFC LOW TO THE TRI STATE
CORNER ABOUT 12 LATER THAN PREVIOUSLY FORECAST. THAT SAID THERE
REMAINS A SLIGHT RISK FOR SEVERE STORMS ACROSS MUCH OF THE AREA ON
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
SATURDAY NIGHT INTO SUNDAY NIGHT...THE STACKED SYSTEM WRAPS MOISTURE
BACK ACROSS MUCH OF THE CWFA. WITH CATEGORICAL POPS FOR THE ENTIRE
FA SUNDAY WITH DEFORMATION BAND OF RAIN. NORTH WINDS WILL
INCREASE INTO THE 20 TO 30 KT RANGE SUNDAY ACROSS THE WEST AND
SLOWLY WORK TO THE EAST DURING THE DAY. AHEAD OF THE SFC LOW AND
WIND SHIFT THERE REMAINS A CHANCE FOR THUNDER WITH NEGATIVE
SHOWALTERS THROUGH EARLY AFTERNOON. AS THE SYSTEM SLOWING PUSHES
EAST 925MB TEMPS ACROSS THE DVL BSN AND N RRV DO DROP WELL BELOW
0C AND MODELS CONTINUE TO HINT AND THE POSSIBILITY OF SOME SNOW
FLAKES MIXED IN WITH THE BACKEND OF THE PCPN SHIELD. TOTAL
RAINFALL AMOUNTS ARE EXPECTED TO BE A WIDESPREAD 1 TO 2 INCHES
THROUGH SUNDAY NIGHT.
MONDAY TO THURSDAY...LONG WAVE RIDGE OVER THE WESTERN CANADA MOVES
LITTLE THROUGH THE PERIOD. LONG WAVE TROUGH OVER NORTHEAST CANADA
SHIFTS EAST INTO EASTERN CANADA. REX BLOCK WAS OVER WESTERN NORTH
AMERICA. COLD FRONT FORECAST TO MOVE THROUGH EARLY IN THE PERIOD.
A SURFACE RIDGE MOVES INTO THE AREA TUE NIGHT. GFS WAS A LITTLE
FASTER THAN THE ECMWF. WILL PREFER THE ECMWF.
HIGH TEMPS WERE LOWERED FOR MON AND TUE BY ONE TO FOURS DEGREES.
LITTLE CHANGE ON WED AND THU WAS INCREASED ONE OR TWO DEGREES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 110 PM CDT FRI MAY 15 2015
IFR/MVFR CLOUD DECK ALG AND SOUTH OF A BDE- VWU- FAR- JMS LINE
WILL SLOWLY SHIFT SOUTHEASTWARD THIS AFTERNOON WITH GENLY FAIR
SKIES BEHIND THE SURFACE COOL FRONT IN NORTHEASTERN ND AND FAR
NWRN MN. EXPECT CLEARING SKIES INTO SOUTHERN RRV BRIEFLY THIS
EARLY EVENING BEFORE INCLREASING MID AND LOW LEVEL MOISTURE MOVES
INTO THE FA AHEAD OF NEXT SYSTEM. OVERNIGHT...MID LVL CLOUDS
SHOULD OVERSPREAD AREA FROM THE SOUTHWEST WITH APPROACHING WARM
FRONTAL BOUNDARY. EXPECT VFR CIGS WITH SCT MVFR CIGS AND VSBYS IN
SHOWERS AND THUNDERSTORMS THROUGH THE DAY ON SATURDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...JK
LONG TERM...HOPPES/JK
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS NORMAN OK
232 PM CDT FRI MAY 15 2015
.DISCUSSION...
SEVERE STORM AND FLASH FLOODING POTENTIAL LATE TONIGHT THROUGH
EARLY SUNDAY ARE THE PRIMARY CONCERNS.
ISSUED A FLASH FLOOD WATCH FOR LOCATIONS SOUTH OF ELK CITY TO
WEATHERFORD TO KINGFISHER TO STILLWATER LINE WHERE THE HEAVIEST
RAINFALL TOTALS DURING THE PAST 10 DAYS HAVE OCCURRED AND WHERE
THE POTENTIAL FOR FLASH FLOODING SEEMS TO BE HIGHEST AS A FEW
ADDITIONAL INCHES OF RAINFALL MAY OCCUR THROUGH SUNDAY MORNING.
LOCATIONS SOUTHEAST OF I-44 SATURDAY NIGHT MAY HAVE THE HIGHEST
RAINFALL AND GREATEST POTENTIAL FOR HEAVY RAINFALL AND FLASH
FLOODING.
THROUGH MIDNIGHT TONIGHT...OVERALL THINK STORM CHANCES WILL BE
LIMITED DUE TO CAPPING. KEPT LOW CHANCES OF STORMS MAINLY OVER
WESTERN OKLAHOMA WHERE BEST HEATING FROM ABUNDANT SUNSHINE IS
CURRENTLY OCCURRING. IF STORMS FORM...THEY COULD BE MARGINALLY
SEVERE WITH HAIL AND WIND. LOWERED RAIN CHANCES DURING THIS TIME
FRAME.
FROM MIDNIGHT TONIGHT TO 7 AM SATURDAY...STORM CHANCES WILL
INCREASE...ESPECIALLY IN WESTERN OKLAHOMA AS STORMS FORMING OVER
THE TEXAS PANHANDLE MOVE EAST. THEY MAY ORGANIZE INTO A CLUSTER
OR LINE AS DEPICTED BY SOME LATEST HRRR AND WRF RUNS. SOME OF
THESE MAY BE SEVERE WITH MARGINAL SEVERE HAIL UP TO HALF DOLLARS
AND WINDS UP TO 70 MPH...THOUGH STORMS SHOULD WEAKEN AS THEY MOVE
EAST THROUGH THE NIGHT INTO A MORE STABLE AND SLIGHTLY WEAKLY
SHEARED ENVIRONMENT. DO NOT THINK SEVERE STORMS WILL BE WIDESPREAD
LATE TONIGHT. LOCALLY HEAVY RAINFALL OF 1 TO 2 INCHES MAY OCCUR
WHICH COULD CAUSE FLASH FLOODING.
BETWEEN 7 AM AND 3 PM SATURDAY...ONGOING WEAKENING STORMS WILL
LIKELY CONTINUE TO SPREAD EAST...POSSIBLY REACHING THE I-44
CORRIDOR AROUND 9 AM IN THE MORNING. THIS MAY LEAVE BEHIND A LOW
LEVEL COLD POOL...ABUNDANT CLOUD COVER...AND MORE STABLE
CONDITIONS ACROSS MUCH OF THE AREA. THE SEVERE THREAT APPEARS TO
BE RATHER LOW DURING THIS TIME FRAME. LOCALLY HEAVY DOWNPOURS MAY
PRODUCE SOME FLASH FLOODING.
BETWEEN 3 PM AND MIDNIGHT SATURDAY...SEVERE THUNDERSTORM POTENTIAL
REMAINS UNCERTAIN...ESPECIALLY AS EARLY DAY STORMS MAY COOL AND
STABILIZE THE AIR. THERE IS A CHANCE FOR THE REDEVELOPMENT OF
SEVERE STORMS NEAR AND JUST EAST OF DRYLINE IN WESTERN OKLAHOMA
AND WESTERN NORTH TEXAS...THEN QUICKLY MOVE NORTHEAST. IF THESE
STORMS REFORM...THEY WOULD LIKELY BE SUPERCELLULAR AND COULD
PRODUCE SIGNIFICANT SEVERE WEATHER WITH VERY LARGE HAIL AND
TORNADOES DUE TO VERY STRONG SHEAR. ANOTHER SCENARIO IS THE THAT
EARLY DAY STORMS LEAVE AN OUTFLOW BOUNDARY NEAR OR SOUTHEAST OF
I-44 FOR THE REDEVELOPMENT OF STORMS NEAR THIS BOUNDARY WHICH
COULD BE SEVERE WITH HAIL...WIND...AND PERHAPS TORNADOES. THIS
SECOND SCENARIO SEEMS TO HAVE LESS POTENTIAL FOR SIGNIFICANT
SEVERE STORMS. MESOSCALE DETAILS WILL HAVE A LARGE IMPACT ON
SEVERE WEATHER POTENTIAL SATURDAY AND SATURDAY NIGHT. LOCALLY
HEAVY RAINFALL BANDS COULD SETUP SOMEWHERE OVER THE AREA AND LEAD
TO FLASH FLOODING...THOUGH EXACTLY WHERE AND WHEN REMAINS VERY
UNCERTAIN.
LATE SATURDAY NIGHT...HEAVY RAINFALL AND FLASH FLOODING POTENTIAL
MAY CONTINUE...ESPECIALLY SOUTHEAST OF I-44...THOUGH SEVERE
POTENTIAL WILL LIKELY DECREASE THROUGH THE NIGHT AS THE AIR BECOME
COOLER AND MORE STABLE. KEPT HIGHEST RAIN CHANCES IN THESE
LOCATIONS.
SUNDAY AND SUNDAY NIGHT...A FEW STORMS MAY LINGER SOUTH OF A
WICHITA FALLS TO ADA LINE THAT MAY PRODUCE LOCALLY HEAVY RAINFALL
AND PERHAPS BE ON STRONG TO PERHAPS SEVERE SIDE.
OTHERWISE...WARM...HUMID...AND RAINFREE CONDITIONS ARE EXPECTED.
MONDAY THROUGH FRIDAY...RAIN CHANCES WILL REMAIN IN THE FORECAST
DURING THIS TIME FRAME...ESPECIALLY TUESDAY NIGHT INTO WEDNESDAY.
ADDITIONAL HEAVY RAINFALL...FLOODING...AND SEVERE STORMS MAY BE
POSSIBLE. TEMPERATURES ARE FORECAST TO BE SLIGHTLY BELOW AVERAGE.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 66 77 62 83 / 20 60 50 10
HOBART OK 62 79 56 81 / 50 70 40 10
WICHITA FALLS TX 66 79 61 83 / 30 70 50 10
GAGE OK 60 81 54 82 / 70 60 30 10
PONCA CITY OK 67 78 61 81 / 20 60 50 10
DURANT OK 68 80 63 80 / 20 50 80 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SUNDAY MORNING
FOR OKZ016>048-050>052.
TX...FLASH FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SUNDAY MORNING
FOR TXZ083>090.
&&
$$
26/17
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1217 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST FROM THE OHIO VALLEY AND INTO
THE REGION LATER THIS AFTERNOON AND TONIGHT...BRINGING
CONSIDERABLE CLOUDINESS THROUGHOUT THE DAY AND A CHANCE OF SHOWERS
BY LATER THIS AFTERNOON. THE FRONT WILL STALL OVER THE REGION THIS
WEEKEND...BRINGING VARIABLE CLOUDS AND A CHANCE OF SHOWERS EACH
AFTERNOON. A COLD FRONT WILL MOVE ACROSS THE AREA MONDAY NIGHT AND
TUESDAY...USHERING IN A COOL AIRMASS FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
HIGH PRESSURE DRIFTING OFF OF THE MID ATLANTIC COAST ATTM. IN ITS
WAKE...A FAIRLY VIGOROUS BUT MOISTURE STARVED UPPER SHORTWAVE
WILL BE MOVING EAST FROM THE LWR GLAKES REGION THE AFTERNOON...AND
OUT-RUNNING THE SFC WARM FRONT.
A SLOWLY ERODING AREA OF LGT-MDT RAIN SHOWERS ACROSS NRN OHIO AND
FAR NWRN PENN AT 16Z IS PROGGED BY THE HRRR TO MOVE ESE AND BREAK
UP EVEN MORE - TO SCATTERED SHRA AND A FEW ISOLATED TSRA ACROSS
THE NW HALF OF THE STATE BY 23Z.
ACROSS THE SE HALF OF THE CWA...EXPECT A 5-15 KT SOUTH TO SSW
BREEZE THIS AFTERNOON WITH SUNSHINE FILTERED THROUGH AREAS OF
CIRRUS AND HIGH ALTO CU. JUST A FEW ISOLATED SHRA/TSRA ARE
POSSIBLE AFTER 20Z ACROSS SCENT/SERN PENN.
BEST OVERALL CHC OF RAIN /70-80 PERCENT/ THIS AFTERNOON APPEARS
TO BE OVR THE NW MTNS...CLOSEST TO TRACK OF THE AFOREMENTIONED
SHORTWAVE. LOWEST POPS OF ONLY ARND 15 PCT FOR A LATE DAY SHRA
WILL CONTINUE TO BE ACROSS THE SE COUNTIES...WHERE AIR MASS WILL
REMAIN RELATIVELY STABLE/DRIER EAST OF WARM FRONT WITH SFC
DEWPOINTS IN THE U40S TO AROUND 50F.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WARM FRONT GETS HUNG UP ACROSS N CENTRAL TONIGHT AS FLAT RIDGE
CONTINUES TO BE IMPACTED BY EMBEDDED SHORTWAVE TROFS. THIS WILL
KEEP CHC OF SHOWERS GOING...ALTHOUGH MUCH OF THE TIME WILL BE RAIN
FREE IN MOST AREAS. BEST CHC FOR SHOWERS WILL COME SATURDAY
AFTERNOON OVER THE WESTERN AND NORTHERN HIGH TERRAIN AS CAPES GROW
TO SEVERAL HUNDRED J/KG AND BOUNDARY PROVIDES A FOCUS/TRIGGER FOR
INITIATION. MINS TONIGHT WILL BE MILD...GENERALLY RANGING FROM THE
UPPER 50S NORTH THROUGH THE 60S SOUTH. HIGHS ON SATURDAY WILL
RANGE FROM THE MID 70S NORTH TO AROUND 80 SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE SURFACE LOW REACHING THE UPPER MIDWEST BY EARLY FRIDAY WILL BE
PRECEDED BY A WARM FRONT AS IT CROSSES THE GREAT LAKES/OH VALLEY
AND REACHES THE MID ATLANTIC AND NORTHEAST STATES BY THIS
WEEKEND. A SUFFICIENT INCREASE IN MOISTURE (PWS) AND INSTABILITY
WILL SUPPORT SCATTERED CONVECTION INTO EARLY NEXT WEEK WITH THE
WARM FRONT AND ALSO WITH A TRAILING SURFACE TROUGH EXTENDING
TOWARD THE NORTHERN APPALACHIANS PROVIDING SOME ADDITIONAL LIFT.
A WELL-DEFINED COLD FRONT SHOULD CROSS THE REGION LATER MONDAY
INTO EARLY TUESDAY WITH THE GREATEST RISK FOR WIDESPREAD SHOWERS
AND T-STORMS. THE PARENT SHORTWAVE TROUGH WILL SUPPRESS THE ERN
RIDGE AND ALLOW COOLER/DRIER AIR TO ARRIVE BY MIDWEEK...AS HIGH
PRESSURE SETTLES SEWD FROM THE UPPER PLAINS INTO THE MID ATLC.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
VARIABLE AMOUNTS/THICKNESS OF MID AND HIGH CLOUDS WILL OCCUR
TODAY ACROSS MUCH OF CENTRAL AND SERN PENN...AHEAD OF A WARM FRONT
LIFTING NE FROM THE OHIO RIVER VALLEY. ACROSS OUR NW/NCENT MTN
ZONES...CLOUDS WILL LOWER AND THICKEN TODAY...THOUGH THE MAINLY
MID CLOUD DECK SHOULD REMAIN IN THE VFR RANGE THROUGH MOST OF THE
DAY.
LATEST HI RESOLUTION MODEL RUNS BRING IN THE SHOWERS THROUGH NWRN
PA BEGINNING AROUND 18Z /APPROX 19Z AT KBFD/ AND MOVING EASTWARD
THROUGH 00Z /IMPACTING TAF SITES MAINLY ALONG AND NORTH OF A KDUJ
TO KIPT LINE...OR NORTH OF INTERSTATE 80/.
MVFR TO IFR POSSIBLE IN ANY OF THE SHOWERS AND THUNDERSTORMS. THE
CHANCES FOR RESTRICTING CONDITIONS WILL CONTINUE TO INCREASE FRIDAY
NIGHT INTO SATURDAY MORNING.
OUTLOOK...
SAT-TUE...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOCAL REDUCTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DEVOIR/LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
103 PM CDT FRI MAY 15 2015
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 1046 AM CDT FRI MAY 15 2015/
UPDATE...
LATEST RADAR SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS GETTING
READY TO PUSH INTO PORTIONS OF NORTHEAST ARKANSAS. MEANWHILE...A
FEW SHOWERS HAVE BEEN DEVELOPING OVER NORTHEAST MISSISSIPPI AND
PORTIONS OF WEST TENNESSEE NEAR THE TENNESSEE RIVER OVER THE PAST
HOUR. LATEST HRRR SHOWS SHOWER AND THUNDERSTORM DEVELOPMENT WILL
EXPLODE OVER THE MIDSOUTH BY 1-2 PM AS A SHORTWAVE MOVES INTO THE
AREA. CURRENT POPS OF 60 LOOK GOOD AS WELL AS THE REST OF THE
FORECAST. NO UPDATES ARE EXPECTED.
KRM
DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
&&
.AVIATION...
12Z TAF CYCLE
MOIST AND UNSTABLE AIRMASS PREVAILS ACROSS THE REGION. GOOD
SURFACE HEATING WILL RESULT IN SCATTERED TO NUMEROUS SHRAS AND
TSRAS ACROSS MUCH OF THE AREA THIS AFTERNOON. EXPECT ACTIVITY TO
DIMINISH WITH LOSS OF HEATING THIS EVENING. ANOTHER ROUND OF
SHRAS/TSRAS IS POSSIBLE LATER TONIGHT AND EARLY SATURDAY AS A
DISTURBANCE...NOW LOCATED OVER TEXAS...MOVES NORTHEAST OVER THE
AREA. TIMING OF SHRA/TSRAS IS DIFFICULT AT BEST AND CONFIDENCE
BEYOND 6 HRS IS LOW. EXPECT A PERIOD OF LOW CLOUDS EARLY SATURDAY
MORNING.
SOUTH WINDS AROUND 10 KTS THROUGH THE PERIOD...SLIGHTLY LESS
OVERNIGHT.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
344 PM CDT FRI MAY 15 2015
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THE MAIN UPDATE WITH THE AFTERNOON PACKAGE WAS TO UPDATE THE
ONGOING FLASH FLOOD WATCH TO ENCOMPASS THE ENTIRE AREA. THE MAIN
THREAT FOR HEAVY RAINFALL NORTH OF INTERSTATE 10 WILL PRIMARILY BE
FROM THE SCATTERED... DAYTIME HEATING DRIVEN THUNDERSTORMS...
WHILE SOUTH OF INTERSTATE 10 WILL NEED TO BE CONCERNED WITH HEAVY
RAINFALL FROM THE EASTWARD MOVING MCS.
TWO DIFFERENT CONVECTIVE SITUATIONS UNFOLDING ACROSS THE REGION
THIS AFTERNOON. THE FIRST... SCATTERED THUNDERSTORMS ALONG AND
EAST OF THE INTERSTATE 45 CORRIDOR THAT HAVE DEVELOPED WHERE
ENOUGH CLOUD THINNING HAS OCCURRED FOR CONVECTIVE TEMPERATURES TO
BE REACHED. THE SECOND... A LINEAR MCS THAT HAS PROPAGATED ACROSS
CENTRAL TEXAS TODAY TOWARDS THE REGION. THE LEADING STRATIFORM
RAIN ASSOCIATED WITH THIS SYSTEM /AS OF 3 PM CDT/ EXTENDS FROM
COLLEGE STATION... TO HOUSTON... TO PALACIOS... AND WILL CONTINUE
TO OVERSPREAD THE REGION AS THE SYSTEM MOVES EAST. ACTIVITY AHEAD
OF THE WESTERNMOST SYSTEM WILL CONTINUE TO WANE WITH LOSS OF
DAYTIME HEATING... BUT THE MCS IS EXPECTED TO MAINTAIN ITSELF INTO
THE REGION WITH THE KHGX VAD WIND PROFILER SHOWING 25 TO 30 KNOTS
OF MOIST SOUTHERLY INFLOW AROUND 4 TO 5 KFT ABOVE THE GROUND
/ROUGHLY AROUND 850 MB/.
LATEST RAP GUIDANCE SHOWS THIS PERSISTING INTO THE EVENING HOURS
AS THE SHORTWAVE AIDING THIS ACTIVITY /AND LOCATED OVER CENTRAL
TEXAS PER WATER VAPOR IMAGERY/ SWINGS NORTH OF THE REGION. ANY
STORM THAT DEVELOPS THROUGH THE EVENING WILL BE CAPABLE OF HEAVY
RAINFALL WITH GPS MET ESTIMATED PRECIPITABLE WATER VALUES AROUND
1.7 INCHES THIS AFTERNOON THAT TREND IS EXPECTED TO CONTINUE. THE
SHORTWAVE LOOKS TO SWING NORTH OF THE REGION LATER TONIGHT
/BETWEEN 9 PM AND 12 AM CDT/... AND SUBSIDENCE BEHIND THIS FEATURE
WILL RESULT IN LOWER RAIN CHANCES OVERNIGHT FOR THE REGION.
THE BREAK IN THE RAIN CHANCES WILL BE SHORT-LIVED AS ANOTHER ROUND
OF DIURNALLY DRIVEN CONVECTION LOOKS TO BREAK OUT TOMORROW
AFTERNOON AS HIGH TEMPERATURES APPROACH THE MID 80S. SOUTHERLY LOW
LEVEL FLOW WILL MAINTAIN 1.5 TO 1.7 INCH PWATS ACROSS THE REGION
AND SIMILAR TO TODAY ANY STORM THAT DEVELOPS WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL. COVERAGE IS NOT ANTICIPATED TO BE AS
WIDESPREAD AS TODAY... ALTHOUGH ANY RESIDUAL BOUNDARIES LEFT OVER FROM
TODAY WILL SERVE AS A FOCUSING MECHANISM FOR STORM DEVELOPMENT.
SOME OF THESE STORMS MAY BRIEFLY BECOME STRONG WITH MUCAPE VALUES
APPROACHING 3000-4000 J/KG... BUT 0-6 KM BULK SHEAR VALUES
GENERALLY AROUND 20 KNOTS WILL DO LITTLE TO PROMOTE STORM
ORGANIZATION. BETTER CHANCES FOR STRONG STORMS FOR THE NORTHWEST
ZONES /COLLEGE STATION FORECAST SOUNDINGS SHOWING SOME STRONGER
SHEAR AROUND 30 KNOTS/.
BY SATURDAY NIGHT... AN UPPER LOW SWINGING ACROSS THE TEXAS AND
OKLAHOMA PANHANDLES INTO THE CENTRAL PLAINS WILL SEND ANOTHER LINE
OF STORMS TOWARDS THE AREA EARLY SUNDAY MORNING AND ANOTHER PERIOD
OF HEAVY RAIN LOOKS TO BE POSSIBLE IN THE EXTENDED.
HUFFMAN
&&
.EXTENDED /SUNDAY THROUGH FRIDAY/...
THUNDERSTORMS MOVING ACROSS THE AREA ON SUNDAY WILL PROVIDE
ANOTHER SHOT AT HEAVY RAINFALL FOR SOUTHEAST TEXAS AS AN UPPER
LEVEL LOW SWINGS NORTH OF THE REGION... WITH ANOTHER ROUND
POSSIBLE INTO MONDAY AS A WEAK COLD FRONT LOOKS TO STALL NEAR THE
REGION. CONTINUING TO MONITOR THE SUNDAY/MONDAY TIMEFRAME FOR
POTENTIAL IMPACTS TO SOUTHEAST TEXAS AS SOILS ARE STILL SATURATED
AND FLOODING CONCERNS ARE POSSIBLE. SOUTHWEST FLOW ALOFT WILL
PERSIST THROUGH MID-WEEK BEFORE A BUILDING RIDGE USHERS IN A
PERIOD OF DRIER WEATHER FOR THE REGION. RIDGING OVERHEAD WILL
ALLOW TEMPERATURES TO SLOWLY WARM ABOVE SEASONAL NORMALS... WITH
LONG TERM GUIDANCE HINTING AT SOME OF THE FIRST 90 DEGREE DAY
WE/VE SEEN THIS YEAR AT THE END OF NEXT WEEK. WIDESPREAD RAIN
CHANCES BEGIN INCREASING NEXT WEEKEND AS ANOTHER UPPER LOW
APPROACHES FROM THE WEST.
HUFFMAN
&&
.MARINE...
A SOLID LINE OF SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING STRONG
WINDS AND HEAVY RAINFALL AND FREQUENT LIGHTNING IS EXPECTED TO MOVE
ACROSS THE AREA THIS AFTERNOON AND THIS EVENING. EXPECT STRONGER
WINDS AND HIGHER SEAS IN AND NEAR THE STORMS. A TIGHTENING PRESSURE
GRADIENT ANTICIPATED OVER THE WEEKEND IS EXPECTED TO BRING INCREASING
WINDS AND BUILDING SEAS TO THE AREA OVER THE WEEKEND. CAUTION FLAGS
ARE IN EFFECT BEGINNING TONIGHT ACROSS THE OFFSHORE WATERS...AND
ADVISORIES MIGHT BE NEEDED OVER THE WEEKEND. CLOSER TO THE COAST...
THE STRENGTHENING WINDS AND BUILDING SEAS MIGHT REACH CAUTION LEVELS.
LOWERING WINDS AND SEAS ARE EXPECTED NEXT WEEK. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 71 85 73 86 73 / 20 30 20 50 50
HOUSTON (IAH) 73 87 75 86 74 / 40 30 20 40 30
GALVESTON (GLS) 76 82 77 83 76 / 40 20 20 30 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
HOUSTON...JACKSON...LIBERTY...MADISON...MATAGORDA...
MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER...
WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION FROM MIDNIGHT CDT TONIGHT
THROUGH LATE SATURDAY NIGHT FOR THE FOLLOWING ZONES: WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...14
AVIATION/MARINE...42
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
114 PM CDT FRI MAY 15 2015
.AVIATION... /18Z TAF UPDATE/
A SLOW DEPARTURE OF THE MORNING MCS WILL CONTINUE TO PRODUCE MINOR
IMPACTS OVER I-35 TERMINALS OVER THE NEXT HOUR OR TWO. BY 20Z ALL
TAF SITES ARE FORECAST TO SEE VFR SKIES AS SUBSIDENCE REPLACES THE
DEPARTING STORM COMPLEX. SOME BRIEF SHIFTINESS AND WEAKENING OF
WINDS ARE EXPECTED IN THE MID AFTERNOON AROUND SAN ANTONIO...BUT
THE PRESSURE GRADIENT SHOULD OTHERWISE TIGHTEN AGAIN FOR A
MODERATE SOUTHEAST BREEZE ACROSS THE AREA. WILL SHOW A CONTINUED
AGGRESSIVE RETURN OF LOW CLOUDS IN THE EVENING AND PATCHY FOG AND
CLOUDS TO DROP CONDITIONS TO IFR FOR MOST AREAS LATE
TONIGHT. AT AROUND SAN ANTONIO WILL SHOW LIFR CIGS TOWARD DAYBREAK AS
SURFACE CONDITIONS CONTINUE TO BE EXTRA MOIST WITH WINDS PROBABLE
TO DECOUPLE MORE IN THAT AREA THAN THE TAF SITES TO THE NORTH AND
WEST. LIGHT SHRA COULD DEVELOP WITH THE LOW LEVEL JET...BUT WILL
KEEP OUT THE POSSIBILITY OF THUNDERSTORMS FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 1222 PM CDT FRI MAY 15 2015/
UPDATE...
BASED ON RADAR TRENDS AND THE LATEST HRRR GUIDANCE...WE HAVE
EXPANDED THE FLASH FLOOD WATCH TO COVER THE COASTAL PLAINS AND
HIGHWAY 77 CORRIDOR. THE WATCH WILL NOW BE IN EFFECT UNTIL 5 PM
CDT.
PREV DISCUSSION... /ISSUED 930 AM CDT FRI MAY 15 2015/
UPDATE...
WE HAVE UPDATED THE FORECAST TO INCREASE RAINFALL CHANCES FOR
AREAS ALONG AND EAST OF I-35 THROUGH THIS MORNING. BACK-BUILDING
THUNDERSTORMS NOTED ACROSS THE RIO GRANDE PLAINS...BUT THIS
ACTIVITY SHOULD SLOWLY TRANSLATE EAST TODAY. WATER VAPOR SATELLITE
LOOP SHOWS MID-LEVEL DRYING COMING IN FROM THE WEST. GIVEN
PERSISTENT SOUTHEASTERLY FLOW AND DAYTIME HEATING...AM CONCERNED
ABOUT ANOTHER ROUND OF CONVECTION DEVELOPING TO OUR WEST THIS
AFTERNOON. WE/LL CONTINUE TO MONITOR CAREFULLY AND AWAIT 12Z MODEL
DATA.
PREV DISCUSSION... /ISSUED 657 AM CDT FRI MAY 15 2015/
AVIATION... /12Z TAF UPDATE/
SLOW MOVING COMPLEX WILL BRING A ROUND OF TSRA THROUGH THE I-35
TERMINALS THROUGH 14-16Z WITH A WEAK MCV TO BRING IMPROVEMENTS
TO POSSIBLY VFR SKIES AT SAT/SSF BY 14Z. IMPROVEMENTS WILL BE
SLOWER TO COME BY AT AUS WHERE ADDITIONAL TRAILING CONVECTION
EXTENDS DEEP INTO THE HILL COUNTRY. NO CONVECTION IS ACCOUNTED FOR
IN THE DRT TAF AS ONLY SOME ISOLATED ACTIVITY IS EXPECTED TO
FORM...WITH NO GOOD MODEL SIGNALS ON TIMING. SATURATED LOW LEVELS
SHOULD LEAD TO QUICK LOW CLOUD FORMATION THIS EVENING WITH MANY
AREAS FALLING INTO IFR OR LOWER LEVELS WITH BOTH CIGS AND PATCHY
FOG AFTER MIDNIGHT.
PREV DISCUSSION... /ISSUED 546 AM CDT FRI MAY 15 2015/
UPDATE...
THE RAINS HAVE ENDED ACROSS THE EDWARDS PLATEAU. THERE MAY BE SOME
LIGHT RAIN IN THE NEXT FEW HOURS. HOWEVER...FLASH FLOODING IS NO
LONGER EXPECTED AND THE FLASH FLOOD WATCH FOR EDWARDS...REAL AND
VAL VERDE COUNTIES HAS BEEN CANCELLED. ALSO...HAVE TRIMMED DOWN
EXPECTED RAINFALL AMOUNTS IN THE REMAINING WATCH AREA TO 1 TO 3
INCHES WITH ISOLATED ADDITIONAL 4 INCHES SINCE THE MCS HAS BECOME
MORE PROGRESSIVE.
PREV DISCUSSION... /ISSUED 402 AM CDT FRI MAY 15 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...
AN OUTFLOW BOUNDARY DEVELOPED AN MCS ACROSS THE RIO GRANDE PLAINS
THURSDAY EVENING. AN UPPER LEVEL SHORTWAVE BRINGING MOISTURE FROM
THE EASTERN PACIFIC AND STRONG DIFFLUENCE ALOFT ALONG WITH A
SOUTHEASTERLY LOWER LEVEL FLOW BRINGING MOISTURE FROM THE GULF OF
MEXICO MAINTAINED THE MCS OVERNIGHT. RADAR TRENDS SHOW THE MCS
STARTING TO MOVE EAST. EXPECT IT TO MAKE IT TO THE I-37 CORRIDOR
THIS MORNING BEFORE IT WEAKENS. THE I-37 CORRIDOR AREA HAD VERY
HEAVY RAINS THURSDAY AFTERNOON INTO EVENING MAKING THE SOILS EVEN
MORE SATURATED FROM RECENT RAINS. EXPECT RAINFALL AMOUNTS OF 2 TO
4 INCHES WITH ISOLATED ADDITIONAL AMOUNTS UP TO 6 INCHES POSSIBLE.
AS A RESULT...HAVE EXPANDED THE FLASH FLOOD WATCH TO INCLUDE SAN
ANTONIO AND BEXAR COUNTY SOUTHEAST TO ATASCOSA...KARNES AND WILSON
COUNTIES. EXPECT THE MCS TO WEAKEN BY MIDDAY WITH THE WATCH
EXPIRING AT NOON. STRONG TO SEVERE STORMS ARE ALSO POSSIBLE WITH
THE MCS. THE UPPER LEVEL SHORTWAVE WILL LINGER OVER SOUTH CENTRAL
TEXAS INTO THE AFTERNOON AND HAVE MAINTAINED HIGH POPS THROUGH
TODAY. THE SHORTWAVE MOVES TO THE NORTHEAST WHILE THE AIRMASS
STABILIZES TONIGHT. HAVE RETAINED SLIGHT CHANCE POPS AS AMPLE
MOISTURE LINGERS. AN UPPER LEVEL TROUGH CURRENTLY CENTERED JUST
OFF POINT CONCEPTION ALONG THE SOUTHERN CALIFORNIA COAST WILL MOVE
ACROSS THE DESERT SOUTHWEST INTO THE ROCKIES ON SATURDAY. UPWARD
FORCING INCREASES LEADING TO CHANCE POPS WITH SOME STRONG STORMS
AND LOCALLY HEAVY RAINS POSSIBLE.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE UPPER LEVEL TROUGH MOVES NORTHEAST ACROSS THE PLAINS SATURDAY
NIGHT INTO SUNDAY WHILE ANOTHER UPPER LEVEL TROUGH DROPS SOUTH OFF
THE WEST COAST. THE UPPER LEVEL JET BECOMES MORE ACTIVE WITH THE
DRYLINE MOVING TO THE EAST. POPS WILL INCREASE AGAIN SATURDAY
NIGHT IN THE NORTH AND ALL AREAS ON SUNDAY. STRONG TO SEVERE
STORMS AND LOCALLY HEAVY RAINS ARE POSSIBLE. SOME FLOODING MAY
RESULT FROM STORMS TRAINING OVER THE SAME AREAS. THE HIGH POPS
CONTINUE INTO MONDAY WHEN A COLD FRONT MAY MOVE INTO CENTRAL
TEXAS PROVIDING ADDITIONAL UPWARD FORCING. THIS NEXT WEST COAST
UPPER LEVEL TROUGH MOVES INLAND ON MONDAY AND THEN INTO THE
NORTHERN ROCKIES BY WEDNESDAY...REPLACED BY YET ANOTHER UPPER
LEVEL TROUGH THAT APPROACHES THE WEST COAST THAT WILL MOVE INTO
THE SOUTHWESTERN STATES ON FRIDAY. WILL MAINTAIN POPS FOR ALL OF
NEXT WEEK DUE TO THESE FEATURES AND OTHER WEAKER DISTURBANCES IN
THE SOUTHWESTERLY FLOW ALOFT. LOOKING AHEAD TO THE MEMORIAL DAY
WEEKEND...THE MODELS INDICATE AT LEAST SLIGHT CHANCE POPS AS THE
PATTERN CONTINUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 82 71 85 72 83 / 80 20 30 50 60
AUSTIN BERGSTROM INTL AIRPORT 82 71 84 73 84 / 80 20 30 40 60
NEW BRAUNFELS MUNI AIRPORT 82 70 84 72 83 / 80 20 30 30 60
BURNET MUNI AIRPORT 80 69 82 70 81 / 60 20 40 70 70
DEL RIO INTL AIRPORT 83 71 87 69 85 / 30 20 30 50 40
GEORGETOWN MUNI AIRPORT 80 70 83 71 82 / 70 20 40 60 70
HONDO MUNI AIRPORT 82 71 85 72 83 / 80 20 30 40 60
SAN MARCOS MUNI AIRPORT 81 71 85 72 83 / 80 20 30 30 60
LA GRANGE - FAYETTE REGIONAL 82 72 85 74 85 / 80 20 30 20 40
SAN ANTONIO INTL AIRPORT 82 71 84 72 83 / 80 20 30 40 60
STINSON MUNI AIRPORT 83 72 86 73 84 / 80 20 30 40 50
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 PM CDT THIS AFTERNOON FOR THE FOLLOWING
COUNTIES: DE WITT...FAYETTE...GONZALES...KARNES...LAVACA...LEE...
WILSON.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1222 PM CDT FRI MAY 15 2015
.UPDATE...
BASED ON RADAR TRENDS AND THE LATEST HRRR GUIDANCE...WE HAVE
EXPANDED THE FLASH FLOOD WATCH TO COVER THE COASTAL PLAINS AND
HIGHWAY 77 CORRIDOR. THE WATCH WILL NOW BE IN EFFECT UNTIL 5 PM
CDT.
&&
.PREV DISCUSSION... /ISSUED 930 AM CDT FRI MAY 15 2015/
UPDATE...
WE HAVE UPDATED THE FORECAST TO INCREASE RAINFALL CHANCES FOR
AREAS ALONG AND EAST OF I-35 THROUGH THIS MORNING. BACK-BUILDING
THUNDERSTORMS NOTED ACROSS THE RIO GRANDE PLAINS...BUT THIS
ACTIVITY SHOULD SLOWLY TRANSLATE EAST TODAY. WATER VAPOR SATELLITE
LOOP SHOWS MID-LEVEL DRYING COMING IN FROM THE WEST. GIVEN
PERSISTENT SOUTHEASTERLY FLOW AND DAYTIME HEATING...AM CONCERNED
ABOUT ANOTHER ROUND OF CONVECTION DEVELOPING TO OUR WEST THIS
AFTERNOON. WE/LL CONTINUE TO MONITOR CAREFULLY AND AWAIT 12Z MODEL
DATA.
PREV DISCUSSION... /ISSUED 657 AM CDT FRI MAY 15 2015/
AVIATION... /12Z TAF UPDATE/
SLOW MOVING COMPLEX WILL BRING A ROUND OF TSRA THROUGH THE I-35
TERMINALS THROUGH 14-16Z WITH A WEAK MCV TO BRING IMPROVEMENTS
TO POSSIBLY VFR SKIES AT SAT/SSF BY 14Z. IMPROVEMENTS WILL BE
SLOWER TO COME BY AT AUS WHERE ADDITIONAL TRAILING CONVECTION
EXTENDS DEEP INTO THE HILL COUNTRY. NO CONVECTION IS ACCOUNTED FOR
IN THE DRT TAF AS ONLY SOME ISOLATED ACTIVITY IS EXPECTED TO
FORM...WITH NO GOOD MODEL SIGNALS ON TIMING. SATURATED LOW LEVELS
SHOULD LEAD TO QUICK LOW CLOUD FORMATION THIS EVENING WITH MANY
AREAS FALLING INTO IFR OR LOWER LEVELS WITH BOTH CIGS AND PATCHY
FOG AFTER MIDNIGHT.
PREV DISCUSSION... /ISSUED 546 AM CDT FRI MAY 15 2015/
UPDATE...
THE RAINS HAVE ENDED ACROSS THE EDWARDS PLATEAU. THERE MAY BE SOME
LIGHT RAIN IN THE NEXT FEW HOURS. HOWEVER...FLASH FLOODING IS NO
LONGER EXPECTED AND THE FLASH FLOOD WATCH FOR EDWARDS...REAL AND
VAL VERDE COUNTIES HAS BEEN CANCELLED. ALSO...HAVE TRIMMED DOWN
EXPECTED RAINFALL AMOUNTS IN THE REMAINING WATCH AREA TO 1 TO 3
INCHES WITH ISOLATED ADDITIONAL 4 INCHES SINCE THE MCS HAS BECOME
MORE PROGRESSIVE.
PREV DISCUSSION... /ISSUED 402 AM CDT FRI MAY 15 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...
AN OUTFLOW BOUNDARY DEVELOPED AN MCS ACROSS THE RIO GRANDE PLAINS
THURSDAY EVENING. AN UPPER LEVEL SHORTWAVE BRINGING MOISTURE FROM
THE EASTERN PACIFIC AND STRONG DIFFLUENCE ALOFT ALONG WITH A
SOUTHEASTERLY LOWER LEVEL FLOW BRINGING MOISTURE FROM THE GULF OF
MEXICO MAINTAINED THE MCS OVERNIGHT. RADAR TRENDS SHOW THE MCS
STARTING TO MOVE EAST. EXPECT IT TO MAKE IT TO THE I-37 CORRIDOR
THIS MORNING BEFORE IT WEAKENS. THE I-37 CORRIDOR AREA HAD VERY
HEAVY RAINS THURSDAY AFTERNOON INTO EVENING MAKING THE SOILS EVEN
MORE SATURATED FROM RECENT RAINS. EXPECT RAINFALL AMOUNTS OF 2 TO
4 INCHES WITH ISOLATED ADDITIONAL AMOUNTS UP TO 6 INCHES POSSIBLE.
AS A RESULT...HAVE EXPANDED THE FLASH FLOOD WATCH TO INCLUDE SAN
ANTONIO AND BEXAR COUNTY SOUTHEAST TO ATASCOSA...KARNES AND WILSON
COUNTIES. EXPECT THE MCS TO WEAKEN BY MIDDAY WITH THE WATCH
EXPIRING AT NOON. STRONG TO SEVERE STORMS ARE ALSO POSSIBLE WITH
THE MCS. THE UPPER LEVEL SHORTWAVE WILL LINGER OVER SOUTH CENTRAL
TEXAS INTO THE AFTERNOON AND HAVE MAINTAINED HIGH POPS THROUGH
TODAY. THE SHORTWAVE MOVES TO THE NORTHEAST WHILE THE AIRMASS
STABILIZES TONIGHT. HAVE RETAINED SLIGHT CHANCE POPS AS AMPLE
MOISTURE LINGERS. AN UPPER LEVEL TROUGH CURRENTLY CENTERED JUST
OFF POINT CONCEPTION ALONG THE SOUTHERN CALIFORNIA COAST WILL MOVE
ACROSS THE DESERT SOUTHWEST INTO THE ROCKIES ON SATURDAY. UPWARD
FORCING INCREASES LEADING TO CHANCE POPS WITH SOME STRONG STORMS
AND LOCALLY HEAVY RAINS POSSIBLE.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE UPPER LEVEL TROUGH MOVES NORTHEAST ACROSS THE PLAINS SATURDAY
NIGHT INTO SUNDAY WHILE ANOTHER UPPER LEVEL TROUGH DROPS SOUTH OFF
THE WEST COAST. THE UPPER LEVEL JET BECOMES MORE ACTIVE WITH THE
DRYLINE MOVING TO THE EAST. POPS WILL INCREASE AGAIN SATURDAY
NIGHT IN THE NORTH AND ALL AREAS ON SUNDAY. STRONG TO SEVERE
STORMS AND LOCALLY HEAVY RAINS ARE POSSIBLE. SOME FLOODING MAY
RESULT FROM STORMS TRAINING OVER THE SAME AREAS. THE HIGH POPS
CONTINUE INTO MONDAY WHEN A COLD FRONT MAY MOVE INTO CENTRAL
TEXAS PROVIDING ADDITIONAL UPWARD FORCING. THIS NEXT WEST COAST
UPPER LEVEL TROUGH MOVES INLAND ON MONDAY AND THEN INTO THE
NORTHERN ROCKIES BY WEDNESDAY...REPLACED BY YET ANOTHER UPPER
LEVEL TROUGH THAT APPROACHES THE WEST COAST THAT WILL MOVE INTO
THE SOUTHWESTERN STATES ON FRIDAY. WILL MAINTAIN POPS FOR ALL OF
NEXT WEEK DUE TO THESE FEATURES AND OTHER WEAKER DISTURBANCES IN
THE SOUTHWESTERLY FLOW ALOFT. LOOKING AHEAD TO THE MEMORIAL DAY
WEEKEND...THE MODELS INDICATE AT LEAST SLIGHT CHANCE POPS AS THE
PATTERN CONTINUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 82 71 85 72 83 / 80 20 30 50 60
AUSTIN BERGSTROM INTL AIRPORT 82 71 84 73 84 / 80 20 30 40 60
NEW BRAUNFELS MUNI AIRPORT 82 70 84 72 83 / 80 20 30 30 60
BURNET MUNI AIRPORT 80 69 82 70 81 / 60 20 40 70 70
DEL RIO INTL AIRPORT 83 71 87 69 85 / 30 20 30 50 40
GEORGETOWN MUNI AIRPORT 80 70 83 71 82 / 70 20 40 60 70
HONDO MUNI AIRPORT 82 71 85 72 83 / 80 20 30 40 60
SAN MARCOS MUNI AIRPORT 81 71 85 72 83 / 80 20 30 30 60
LA GRANGE - FAYETTE REGIONAL 82 72 85 74 85 / 80 20 30 20 40
SAN ANTONIO INTL AIRPORT 82 71 84 72 83 / 80 20 30 40 60
STINSON MUNI AIRPORT 83 72 86 73 84 / 80 20 30 40 50
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 PM CDT THIS AFTERNOON FOR THE FOLLOWING
COUNTIES: DE WITT...FAYETTE...GONZALES...KARNES...LAVACA...LEE...
WILSON.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...30
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
127 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1207 PM EDT FRIDAY...
MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES
ALONG AND EAST OF THE SOUTHERN BLUE RIDGE MOUNTAINS WITH MVFR
CLOUDS HOLDING LONGER. IT WILL TAKE A FEW HOURS LONGER BEFORE
LOW CLOUDS LIFT THIS AFTERNOON.
AS OF 946 AM EDT FRIDAY...
ADJUSTED TEMPERATURES AND DEWPOINTS WITH THE LATEST OBS AND MODEL
TRENDS. MODIFIED CLOUD COVER TOWARDS LATEST SATELLITE IMAGE AND
TRENDED LATE MORNING INTO THIS AFTERNOON TOWARDS A BLEND OF THE
CANADIAN AND HRRR...WHICH CAPTURE THE SUNSHINE ACROSS SOUTHEAST
WEST VIRGINIA AND NEW RIVER VALLEY WITH RICHER CLOUDS ALONG THE
SOUTHERN BLUE RIDGE. HEATING WILL CREATE INSTABILITY COMBINED WITH
CAPES OF AROUND 500 TO 1000 J/KG TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS. DAY ONE CONVECTIVE OUTLOOK PLACES THE SEVERE
THREAT TO OUR WEST. ALLOWED FOR LIGHT SHOWERS ALONG THE SOUTHERN
BLUE RIDGE THEN SHAPED POPS FOR LATE THIS MORNING INTO THIS
AFTERNOON TOWARDS A HRRR/RNK WRFARW. HIGH TEMPERATURES THIS
AFTERNOON WILL RANGE FROM THE UPPER 60S IN THE MOUNTAINS TO AROUND
80 DEGREES IN THE PIEDMONT.
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 130 PM EDT FRIDAY...
SHORTWAVE OVER THE REGION WILL MOVE EAST THIS AFTERNOON INTO
TONIGHT AND WILL FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST.
SOUTHWEST FLOW ABOVE THE SURFACE WILL CONTINUE TO TRANSPORT
MOISTURE INTO THE REGION.
A PERSISTENT LAYER OF MVFR STRATOCUMULUS REMAINS ALONG AND EAST
OF THE SOUTHERN BLUE RIDGE MOUNTAIN EXTENDING INTO THE SOUTHERN
PIEDMONT. THE ONLY TAF SITE BEING AFFECT BY THIS MVFR CLOUDS IS KDAN.
HOWEVER...WITH MIXING THIS AFTERNOON THIS IS EXPECTED TO LIFT TO
VFR CONDITIONS DURING THE NEXT COUPLE OF HOURS.
MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS. THE THREAT OF
THUNDERSTORMS HAS BEEN LIMITED BY THE UPPER RIDGE AND COVERAGE OF
CLOUD COVER. PROBABILITY IS HIGH ENOUGH TO INCLUDE MENTION OF SHOWERS
OR VCSH IN WESTERN MOUNTAIN TAF SITES THIS AFTERNOON INTO
TONIGHT. KBLF IS THE TAF SITE WITH THE BEST CHANCE FOR A
THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING...BUT BECAUSE OF
LIMITED COVERAGE WILL LEAVE MENTION OUT. ANY CONVECTION WILL
DISSIPATE QUICKLY TONIGHT WITH LOSS OF SOLAR HEATING. IF A
THUNDERSTORMS OCCURS AND IT RAINS ENOUGH AT A TAF LOCATION...WE
MAY NEED TO INSERT SOME PATCHY FOG OVERNIGHT.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
MEDIUM TO HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS
DURING THE TAF PERIOD.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY. DRIER AND COOLER AIR EXPECTED BEHIND THE FRONT
FOR MIDWEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1208 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1207 PM EDT FRIDAY...
MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES
ALONG AND EAST OF THE SOUTHERN BLUE RIDGE MOUNTAINS WITH MVFR
CLOUDS HOLDING LONGER. IT WILL TAKE A FEW HOURS LONGER BEFORE
LOW CLOUDS LIFT THIS AFTERNOON.
AS OF 946 AM EDT FRIDAY...
ADJUSTED TEMPERATURES AND DEWPOINTS WITH THE LATEST OBS AND MODEL
TRENDS. MODIFIED CLOUD COVER TOWARDS LATEST SATELLITE IMAGE AND
TRENDED LATE MORNING INTO THIS AFTERNOON TOWARDS A BLEND OF THE
CANADIAN AND HRRR...WHICH CAPTURE THE SUNSHINE ACROSS SOUTHEAST
WEST VIRGINIA AND NEW RIVER VALLEY WITH RICHER CLOUDS ALONG THE
SOUTHERN BLUE RIDGE. HEATING WILL CREATE INSTABILITY COMBINED WITH
CAPES OF AROUND 500 TO 1000 J/KG TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS. DAY ONE CONVECTIVE OUTLOOK PLACES THE SEVERE
THREAT TO OUR WEST. ALLOWED FOR LIGHT SHOWERS ALONG THE SOUTHERN
BLUE RIDGE THEN SHAPED POPS FOR LATE THIS MORNING INTO THIS
AFTERNOON TOWARDS A HRRR/RNK WRFARW. HIGH TEMPERATURES THIS
AFTERNOON WILL RANGE FROM THE UPPER 60S IN THE MOUNTAINS TO AROUND
80 DEGREES IN THE PIEDMONT.
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1258 PM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI MAY 15 2015
BIGGEST CHANGE TO THIS PERIOD WILL BE TO REMOVE THE SEVERE STORM
POTENTIAL OVERNIGHT CURRENTLY IN THE SERVICE SUITE.
SATELLITE AND SURFACE OBSERVATIONS SHOWING A VERY WEAK PRESSURE
GRADIENT AND LOW CLOUD AND FOG FAIRLY WIDESPREAD ACROSS THE
REGION IN THE WAKE OF THE RAIN. STILL SOME DRIZZLE BEING REPORTED
IN WI IN WHAT THE RAP SOUNDINGS INDICATE AS A 2KM DEEP MOIST
LAYER. SPORADIC REPORTS OF NEAR ZERO VISIBILITY ARE OUT THERE AS
OF 08Z /MAINLY IOWA/...BUT WEB CAMERAS ACROSS THE AREA DONT REVEAL
WIDESPREAD REDUCTIONS TO VISIBILITY. OVERALL IDEA TODAY IS
SHORTWAVE RIDGING BUILDING IN AND DEEPER MIXING...BUT HAVE TAKEN A
PESSIMISTIC APPROACH WITH MORE SUN SEEN IN THE AFTERNOON. WILL
CONTINUE TO MONITOR FOR MORE WIDESPREAD FOG ISSUES AND FOR NOW
WILL HANDLE THIS WITH SPECIAL WX STATEMENTS.
PREVIOUS FORECAST AND CURRENT MESSAGING CONTAINS A SEVERE RISK
OVERNIGHT AS THE WARM FRONT...NOW LOCATED ROUGHLY ALONG
I-80...LIFTS INTO THE AREA. A SECONDARY MARITIME TROPICAL AIRMASS
RESIDES SOUTH OF I-70 WITH 65-70F DEWPOINTS...NOT TOO FAR AWAY.
THE 15.00Z NAM IS REALLY THE OUTLIER ON THE MUCAPE FORECAST INTO
THE AREA /THROUGH ITS ENTIRE FORECAST/ AND FEEL IT MUST BE REDUCED
ABOUT 30 PERCENT BASED ON SOUNDINGS AND LATEST MODEL CONSENSUS. AS
THE SPOKE OF ENERGY FROM THE SWRN U.S. LONG WAVE TROUGH ROTATES
NORTH //NOW IN NM/AZ//...HEIGHTS WILL FALL IN THE LOW-LEVELS AND
THE MOISTURE TRANSPORT WILL ENHANCE IN THE DAKOTAS/WRN MN...BUT
PRETTY FAR WEST. BY THE THE OVERNIGHT HOURS...AN AXIS OF MOISTURE
CONVERGENCE AND ABOUT 500 J/KG OF MUCAPE WILL RUN FROM KABR-KLSE.
BETTER CONVERGENCE ALONG THE WARM FRONT IN THE LOW LEVELS WILL BE
OCCURRING FURTHER WEST. HAVE KEPT 30S PERCENT CHANCES FOR THAT
PERIOD FOR THUNDERSTORMS...BUT THE WIND SHEAR IS VERY LOW AND THE
LESS AGGRESSIVE MODELS WITH MOISTURE /15.00Z GFS/ SUGGEST SOME
CAPPING OF 50-80J IS IN PLACE FOR 1-2KM PARCELS BEING LIFTED. SO
COVERAGE OF STORMS IS ALSO IN QUESTION. OVERALL...DIDNT SEE AN
ORGANIZED THREAT TO SPEAK OF FOR MESSAGING IN OUR SERVICE. WILL BE
PULLING THAT MENTION. SPC DAY 1 OUTLOOK WOULD AGREE WITH THIS
ASSESSMENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI MAY 15 2015
SATURDAY WILL SEE WARMER CONDITIONS AS THE WARM FRONT SHIFTS FURTHER
NORTH INTO THE NORTHERN FORECAST AREA AND NRN WI. DEWPOINTS AND
CAPE WILL BE ON THE INCREASE AND PROBABLY ABOUT 1000 J/KG OF
MLCAPE WILL BE PRESENT IN THE AFTERNOON. HOWEVER...FORCING IS
MINIMAL DURING PEAK HEATING WITH FAIRLY UNIFORM S-SE FLOW IN THE
FORECAST AREA IN THE WARM SECTOR. THE WILD CARD MAY BE ANY
CONVECTIVE VORTICITY THAT IS GENERATED IN THE SRLY FLOW. HAVE LEFT
SMALL RAIN CHANCES IN THE AFTERNOON. IT COULD BE A WARM DAY
SATURDAY AND BUMPED HIGHS A BIT WITH 19-21C SUGGESTED AT 925MB
FROM THE 15.00Z GUIDANCE /4-5C WARMER THAN FRIDAY/.
THE BIG STORY CONTINUES TO BE THE SUNDAY POTENTIAL FOR SEVERE
STORMS. POTENTIAL IS A GOOD WORD AS IT COULD BE A FAVORABLE DAY
FOR TORNADOES...BUT ALSO COULD RAIN THROUGH THE MORNING AND TURN
INTO NO STORY. THERE IS A BIG DIFFERENCE BETWEEN THE
DETERMINISTIC GUIDANCE WITH THE 15.00Z AND 14.18Z NAM RUNS SUGGESTING
A GOOD SETUP FOR SUPERCELL TORNADOES AND THE OVERALL SYNOPTICS AND
TIMING. HOWEVER...IT IS AN OUTLIER AS THE 15.00Z ECMWF/GFS AND
15.03Z/21Z SREFS ALL SUGGEST A DIFFERENT OUTCOME. THAT OUTCOME
WOULD INCLUDE STRONG MOISTURE TRANSPORT CONVERGENCE COMING INTO
THE AREA EARLY ON SUNDAY FROM THE WEST /SUNRISE/ AND SHIFTING EAST
ACROSS THE AREA. THERE WOULD PROBABLY BE ENOUGH INSTABILITY AND
INCREASING DEEPER STRONGER SHEAR FOR SOME MARGINALLY SEVERE
STORMS THEN. POSSIBLY A SMALL WINDOW IN WI FOR SEVERE STORMS TO
REDEVELOP LATER...BUT THIS SEEMS TO SHIFT NORTHEAST QUICKLY. THE
SLOWER 15.00Z AND 14.18Z NAM RUNS SUGGEST A SLOWER TIMING AND LESS
MORNING CONVECTION INTO WI...FAVORING A BETTER SUNDAY AFTERNOON
SEVERE STORM OUTBREAK.
IMPORTANTLY...SUNDAY HAS EXCELLENT DEEP SHEAR THROUGH 10KM...AND
TIMING AND INSTABILITY ARE THE MAIN PROBLEMS THAT NEED RESOLUTION. SPC
DAY 3 DISCUSSION MAINTAINS THE SLIGHT RISK OVER THE AREA...WHICH
SEEMS ON TRACK FOR THE DIFFERENCES THAT REMAIN ON SUNDAYS OUTCOME.
IT IS ONLY FRIDAY MORNING...AND THESE SWRN U.S. SYSTEMS ARE VERY
DEPENDENT ON THE ENERGY OVER THE PACIFIC BEING RESOLVED CORRECTLY
BY THE MODEL INITIALIZATION. THE NAM SKILL IN THE OUTER HOURS IS
NOT AS FAVORABLE AS WITHIN A DAY. WILL TRY TO STRESS THAT
DIFFERENCES EXIST ON HOW SUNDAY COULD PLAY OUT...BUT THAT A RISK
OF ORGANIZED SEVERE WEATHER EXISTS.
MONDAY THROUGH THURSDAY...AFTER THIS DEEPENING LOW AND SHOWER
CHANCES SHIFT EAST...THE WEEK SHOULD HAVE SLIGHTLY BELOW NORMAL
TEMPERATURES AND MAINLY DRY UNDER CONFLUENT NORTHWEST FLOW AND
CANADIAN SOURCED HIGH PRESSURE. COLDEST DAYS WILL BE MONDAY AND
TUESDAY...THEN SOME RISE EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1258 PM CDT FRI MAY 15 2015
MVFR STRATUS WILL SCATTER OUT LATE THIS AFTERNOON WITH CLOUD
BASES IN THE 1800 TO 2500 FT RANGE. INCREASING MOISTURE ACROSS THE
REGION WILL PRODUCE BR LATE TONIGHT WITH THE POTENTIAL TO SEE
SOME PATCHY FOG AT TIMES. PLAN ON VISIBILITIES FALLING TO AROUND
3SM AT KRST AND 4SM AT KLSE AFTER MIDNIGHT. LOWER VISIBILITIES ARE
POSSIBLE. AFTER THE FOG DISSIPATES SATURDAY MORNING PLAN ON
SCATTERED CUMULUS FOR THE MID TO LATE MORNING HOURS WITH THE
CHANCE OF SEEING AN ISOLATED THUNDERSTORM OR TWO.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION...WETENKAMP