Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/22/15
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
1253 PM CDT WED MAY 20 2015
.AVIATION...
DRIER AIR MOVING INTO SOUTHERN ARKANSAS...WITH CONDITIONS
IMPROVING THROUGH THE AFTERNOON. HOWEVER...WITH ABUNDANT
RAINFALL...CONDITIONS WILL DETERIORATE AND IFR CIGS WILL BE
POSSIBLE OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1035 AM CDT WED MAY 20 2015/
DISCUSSION...
MID MORNING UPDATE LOWERED POPS IN THE WEST TO CENTRAL AR...WHILE
THE HIGHEST IN THE EAST. RADAR TRENDS ARE TAKING MUCH OF THE RAIN
OUT OF THE CWA BY NOON...THEN SHORT RANGE MODELS ONLY SHOW LOW
AMOUNTS OVER THE STATE THE REST OF TODAY. UNTIL THE SURFACE LOW
PULLS EAST AND THE COLD FRONT IS TOTALLY THROUGH AR...WILL HAVE TO
KEEP SOME CHANCES OF RAIN...ISOLATED THUNDER...IN THE FORECAST. AT
MID MORNING THE SURFACE LOW WAS OVER SW MO...WITH THE COLD FRONT
SOUTHWEST TO EASTERN OK. WILL SEE IT GRADUALLY MOVE THROUGH AR TODAY
TO THIS EVENING...WITH A WIND SHIFT TO THE W TO NW BEHIND THE FRONT.
LATER THIS EVENING...THE FRONT IS EXPECTED IN SOUTHERN AR...BUT
LOCATION WILL BE A BIT UNCERTAIN...ESPECIALLY HOW FAR SOUTH IT GOES.
AT SOME POINT OVER SOUTHERN AR THE STEERING FLOW WILL BECOME
PARALLEL AND BOUNDARY WILL STALL...MORE LIKELY NEAR THE AR AND LA
STATE LINE. LATE MORNING UPDATE WILL ADJUST POPS THIS
AFTERNOON...CLOUDS...TEMPS AND WINDS. (59)
PREV DISCUSSION... /ISSUED 417 AM CDT WED MAY 20 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...58
AREA FORECAST DISCUSSION...UPDATE
NWS LITTLE ROCK AR
1035 AM CDT WED MAY 20 2015
.DISCUSSION...
MID MORNING UPDATE LOWERED POPS IN THE WEST TO CENTRAL AR...WHILE
THE HIGHEST IN THE EAST. RADAR TRENDS ARE TAKING MUCH OF THE RAIN
OUT OF THE CWA BY NOON...THEN SHORT RANGE MODELS ONLY SHOW LOW
AMOUNTS OVER THE STATE THE REST OF TODAY. UNTIL THE SURFACE LOW
PULLS EAST AND THE COLD FRONT IS TOTALLY THROUGH AR...WILL HAVE TO
KEEP SOME CHANCES OF RAIN...ISOLATED THUNDER...IN THE FORECAST. AT
MID MORNING THE SURFACE LOW WAS OVER SW MO...WITH THE COLD FRONT
SOUTHWEST TO EASTERN OK. WILL SEE IT GRADUALLY MOVE THROUGH AR TODAY
TO THIS EVENING...WITH A WIND SHIFT TO THE W TO NW BEHIND THE FRONT.
LATER THIS EVENING...THE FRONT IS EXPECTED IN SOUTHERN AR...BUT
LOCATION WILL BE A BIT UNCERTAIN...ESPECIALLY HOW FAR SOUTH IT GOES.
AT SOME POINT OVER SOUTHERN AR THE STEERING FLOW WILL BECOME
PARALLEL AND BOUNDARY WILL STALL...MORE LIKELY NEAR THE AR AND LA
STATE LINE. LATE MORNING UPDATE WILL ADJUST POPS THIS
AFTERNOON...CLOUDS...TEMPS AND WINDS. (59)
&&
.PREV DISCUSSION... /ISSUED 656 AM CDT WED MAY 20 2015/
.AVIATION...20/12Z TAF CYCLE
VFR CONDS WL CONT ACRS SERN AR UNTIL CONVECTION ARRIVES THERE
TOWARDS MID MRNG. ELSEWHERE...MVFR/IFR CONDS WL PREVAIL THIS MRNG
AS A COMPLEX OF SHRA/TSRA CONTS TO AFFECT MUCH OF AR. THE ENTIRE
SYS WL EVENTUALLY SHIFT EWD...WITH ASSOCD PRECIP TAPERING OFF ACRS
WRN AR LATER THIS MRNG. THIS TREND WL CONT OVR CNTRL AND ERN AR
EARLY THIS AFTN. EXPECT VFR/MVFR CIGS TO LINGER OVR THE AREA INTO
THIS EVENING...WITH MVFR CIGS BCMG MORE PREVALENT AFT 21/06Z. /44/
&&
.PREV DISCUSSION... /ISSUED 417 AM CDT WED MAY 20 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
656 AM CDT WED MAY 20 2015
.AVIATION...20/12Z TAF CYCLE
VFR CONDS WL CONT ACRS SERN AR UNTIL CONVECTION ARRIVES THERE
TOWARDS MID MRNG. ELSEWHERE...MVFR/IFR CONDS WL PREVAIL THIS MRNG
AS A COMPLEX OF SHRA/TSRA CONTS TO AFFECT MUCH OF AR. THE ENTIRE
SYS WL EVENTUALLY SHIFT EWD...WITH ASSOCD PRECIP TAPERING OFF ACRS
WRN AR LATER THIS MRNG. THIS TREND WL CONT OVR CNTRL AND ERN AR
EARLY THIS AFTN. EXPECT VFR/MVFR CIGS TO LINGER OVR THE AREA INTO
THIS EVENING...WITH MVFR CIGS BCMG MORE PREVALENT AFT 21/06Z. /44/
&&
.PREV DISCUSSION... /ISSUED 417 AM CDT WED MAY 20 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
417 AM CDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
&&
.LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 68 52 68 51 / 70 30 10 10
CAMDEN AR 86 63 73 59 / 70 40 20 10
HARRISON AR 70 49 66 50 / 70 20 10 10
HOT SPRINGS AR 83 62 71 56 / 70 30 20 10
LITTLE ROCK AR 81 60 71 56 / 70 30 20 10
MONTICELLO AR 85 63 71 57 / 70 30 20 10
MOUNT IDA AR 83 59 70 54 / 70 30 20 10
MOUNTAIN HOME AR 67 49 68 51 / 70 20 10 10
NEWPORT AR 70 52 67 51 / 70 40 10 10
PINE BLUFF AR 83 61 70 56 / 70 30 20 10
RUSSELLVILLE AR 80 58 71 55 / 70 20 20 10
SEARCY AR 76 57 69 51 / 70 40 10 10
STUTTGART AR 79 58 70 54 / 70 40 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...65 / LONG TERM...44
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1001 PM MDT THU MAY 21 2015
.UPDATE...
ISSUED AT 1001 PM MDT THU MAY 21 2015
FORECAST IS LOOKING PRETTY GOOD. EASTWARD PROGRESSION OF SHOWERS
REMAINS A LITTLE SLOW...BUT WITH THE LIFT AND COOLING ALOFT
ARRIVING SHOWERS HAVE FORMED ALONG THE LOWER FOOTHILLS THE LAST
COUPLE OF HOURS...A SIGN THAT THE ENVIRONMENT IS BECOMING MORE
FAVORABLE. STILL EXPECTING THESE TO SPREAD EASTWARD OVER THE NEXT
COUPLE OF HOURS. UPSTREAM RADAR SHOWS A BIT OF A BREAK OVER SOUTH
CENTRAL COLORADO THEN SOME STRONGER CONVECTION ON THE BACK EDGE OF
THE SHORTWAVE...BUT SUSPECT THAT THIS DRIER AREA WILL ACTUALLY
FILL IN WHEN IT GETS EAST OF THE MOUNTAINS INTO THE BETTER
MOISTURE AND CONVERGENCE. SO THE FORECAST OF A BROADER RAIN BAND
FORMING AND MOVING OVER NORTHEASTERN COLORADO LATER TONIGHT AND
EARLY FRIDAY MORNING STILL LOOKS GOOD. I DID LOWER THE LOW
TEMPERATURES A COUPLE OF DEGREES BASED ON CURRENT TRENDS...SNOW
LEVEL MAY DROP AS LOW AS 9000 FEET BUT THE HEAVIEST SNOW AND
IMPACT SHOULD BE ABOVE 10 THOUSAND.
ONLY MINOR CHANGES TO THE RIVER FORECAST. CURRENT CREST MOVING
INTO MORGAN COUNTY...AND ANOTHER OF SIMILAR HEIGHT EXPECTED TO
PASS THROUGH WELD AND MORGAN COUNTIES OVER THE WEEKEND. ONLY MINOR
FLOODING AND ATTENUATING INTO HIGH FLOWS A LITTLE BELOW FLOOD
STAGE BELOW FORT MORGAN...UNLESS THERE IS HEAVIER RAIN THAN
EXPECTED AT SOME POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 339 PM MDT THU MAY 21 2015
CLOUD COVER OVER THE FORECAST AREA HAS BEEN INCREASING AS AN
EJECTING UPPER LEVEL TROUGH ROTATES INTO THE STATE FROM THE SOUTH.
SCATTERED SHOWER ACTIVITY HAS DEVELOPED OVER THE MOUNTAINS BUT
CONVECTION ON THE PLAINS HAS BEEN LIMITED BY THE STABLE LAYER IN
PLACE ACROSS NORTHEAST COLORADO. LATER THIS EVENING...DYNAMIC
FORCING ALOFT SHOULD PRODUCE A WIDESPREAD SHIELD OF PRECIPITATION
THAT EXTENDS FROM THE MOUNTAINS OUT ACROSS THE PLAINS. SNOW LEVELS
IN THE MOUNTAINS SHOULD GRADUALLY COME DOWN...BUT ONLY TO ABOUT
9500 OR 10 THOUSAND FEET. HIGHER MOUNTAIN PASSES ARE EXPECTED TO
PICK UP SEVERAL INCHES OF SNOW...AND THE WINTER WEATHER ADVISORY
REMAINS IN EFFECT FOR THIS.
SHORT RANGE MODELS CONTINUE TO SHOW GENERALLY LIGHT AMOUNTS OF QPF
FROM THIS SYSTEM...WITH THE RAP RUN SHOWING ONE-HALF INCH OR LESS
ACROSS THE PLAINS. ANY RAIN THAT FALLS WILL NOT TAKE VERY LONG TO
FIND ITS WAY TO CREEKS AND STREAMS SINCE THE GROUND REMAINS SO
CLOSE TO SATURATION. LIGHTER AMOUNTS OF RAIN SHOULD REDUCE THE
STRAIN ON THE HYDROLOGIC SITUATION. RIVER LEVELS IN THE DENVER AND
BOULDER AREA HAVE PLENTY OF CAPACITY TO HANDLE TONIGHTS RAINFALL.
LINGERING LIGHT RAIN SHOWERS ARE EXPECTED FRIDAY MORNING AS THE
UPPER TROUGH SLOWLY EXITS THE STATE. THERE SHOULD BE A BREAK IN
THE RAIN BY MIDDAY...BUT AFTERNOON HEATING OF THE MOIST AIRMASS
MAY DE-STABILIZE THE ATMOSPHERE AND PRODUCE SCATTERED
THUNDERSTORMS LATE IN THE AFTERNOON. TEMPERATURES ARE FORECAST TO
BE 5-10 DEGREES WARMER THAN THIS AFTERNOON. THE THREAT OF
LOCALIZED FLOOD PROBLEMS FRIDAY AFTERNOON WILL HINGE ON HOW MUCH
RAIN FALLS TONIGHT AND WHETHER AFTERNOON STORMS TRACK OVER AREAS
THAT RECEIVE APPRECIABLE RAIN TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 PM MDT THU MAY 21 2015
SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS ON FRIDAY
EVENING ARE EXPECTED TO GRADUALLY DECREASE AS THE AIRMASS
STABILIZES...WITH MOST AREAS SEEING PARTIAL CLEARING OVERNIGHT.
SATURDAY IS SHAPING UP TO BE A MORE ACTIVE WEATHER DAY. THE LATEST
MODEL RUNS INDICATE A STRONGER WAVE WITH LARGE SCALE Q-G
ASCENT...NOW LOCATED IN THE EASTERN PACIFIC...ROTATING NORTHEAST
OUT OF THE SOUTHWEST U.S. TROUGH. THE FORECAST AREA WILL LIKELY
RESIDE NEAR THE RIGHT REAR ENTRANCE REGION OF A DEPARTING JET AND
THE LEFT EXIT REGION OF AN APPROACHING SPEED MAX BY AFTERNOON. AT
THE SAME TIME...LOW/MID LEVEL WIND FIELDS WILL BE STRENGTHENING...
AND A SURFACE LOW PRESSURE IS EXPECTED TO DEEPEN OVER EASTERN
COLORADO. THIS WOULD PUT A DRYLINE INTO PLAY DEPENDING EXACTLY ON
WHERE THE SURFACE LOW DEEPENS. THINK THE GFS IS OVERDOING THE LOW
LEVEL DRYING OVER NORTHEAST COLORADO...SO AT THIS TIME FAVOR THE
ECMWF/NAM DEPICTION. CAPES ALONG AND AHEAD OF POTENTIAL DRYLINE
WOULD BE CAPABLE OF INCREASING TO 1500-2000 J/KG WITH SUFFICIENT
HEATING AND T/TD OF 68/50. WIND SHEAR WOULD SUPPORT SUPERCELLS
WITH LARGE HAIL AND TORNADO POTENTIAL...BUT ONLY IF WE GET THE
REQUIRED HEATING. WILL CONTINUE TO MONITOR THIS SEVERE POTENTIAL
THROUGH SATURDAY.
BY SUNDAY...AIRMASS IS STILL EXPECTED TO BE UNSTABLE UNDER
GENERAL TROUGHINESS. BOTH WIND SHEAR AND INSTABILITY WOULD BE A
LITTLE WEAKER THOUGH. SEVERE THREAT IS STILL THERE BUT LOWER THAN
SATURDAY. WILL CONTINUE THE FORECAST OF SCATTERED SHOWERS AND
THUNDERSTORMS.
MONDAY THROUGH MOST OF NEXT WEEK WILL FEATURE MORE AFTERNOON AND
EVENING CONVECTION EACH DAY WITH PLENTY OF RESIDUAL MOISTURE.
HOWEVER...TEMPERATURES WILL BE MODERATING AS FLOW ALOFT TURNS
MORE WESTERLY AND WE SHOULD FINALLY SEE MORE SUNSHINE AT LEAST
DURING THE MORNING HOURS. POTENTIAL FOR EMBEDDED DISTURBANCES
THROUGH THIS PERIOD BUT HARD TO TIME THESE RIGHT NOW.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1001 PM MDT THU MAY 21 2015
MVFR CONDITIONS WILL PREVAIL OVERNIGHT AS RAIN BECOMES WIDESPREAD.
LOCALIZED IFR IS POSSIBLE. CONDITIONS WILL IMPROVE BETWEEN 15Z AND
18Z AS THE RAIN MOVES OUT...BUT INSTRUMENT APPROACHES TO KDEN WILL
LIKELY STILL BE NEEDED. SCATTERED SHOWERS WILL REDEVELOP IN THE
LATE AFTERNOON AND EVENING WITH LOCALIZED MVFR CONDITIONS AGAIN.
&&
.HYDROLOGY...
ISSUED AT 339 PM MDT THU MAY 21 2015
FLOOD WARNINGS CONTINUE FOR THE SOUTH PLATTE FROM CENTRAL WELD
COUNTY INTO WESTERN MORGAN COUNTY. AT THIS TIME...GENERALLY MINOR
FLOODING IS ANTICIPATED WITH WATER LEVELS BELOW LAST WEEKS CREST.
CONTINUED MINOR FLOODING IS STILL ANTICIPATED ON THE CACHE LA
POUDRE IN WESTERN WELD COUNTY THROUGH EARLY NEXT WEEK.
NO APPRECIABLE RAIN HAS FALLEN IN THE PAST 36-48 HOURS SO THE
RIVERS SHOULD CONTINUE A SLOW DECREASE THROUGH THIS EVENING EXCEPT
FOR THE FLOOD CREST MOVING DOWN THE SOUTH PLATTE WHICH WILL MOVE
THROUGH FORT MORGAN AFTER MIDNIGHT.
ANOTHER ORGANIZED SHORTWAVE WILL MOVE THROUGH THE REGION TONIGHT
WITH MORE LIGHT TO MODERATE RAIN AND SOME EMBEDDED
THUNDERSHOWERS. TOTAL LIQUID PRECIPITATION IS EXPECTED TO RANGE
FROM .25 TO .75 INCHES ON THE PLAINS WITH UPWARDS OF AN INCH
POSSIBLE IN THE MOUNTAINS AND HIGHER FOOTHILLS. ALTHOUGH THESE
AMOUNTS DO NOT SEEM LARGE...THE SATURATED GROUND CONDITIONS
SHOULD RESULT IN EFFICIENT RUNOFF. RIVERS AND STREAMS THAT ARE
ALREADY RUNNING HIGH WILL CONTINUE TO DO SO.
SATURDAY WILL HAVE POTENTIAL FOR STRONGER THUNDERSTORMS WITH
HEAVY RAINFALL AND A FLASH FLOOD THREAT. PRECIPITABLE WATER
VALUES NEAR 0.70 TO 0.90 INCH ON THE PLAINS AND ANY STRONGER DEEP
CONVECTION THAT DEVELOPS WOULD SUPPORT POTENTIAL FOR QUICK 1 TO
1.5 INCH RAINFALL AMOUNTS FROM THE ISOLATED STRONGER STORMS. FLASH
FLOOD GUIDANCE CONTINUES TO DROP WITH ADDITIONAL RAINFALL AND SOIL
SATURATION. SUNDAY MAY ALSO SEE SOME THREAT OF LOCALIZED FLASH
FLOODING BUT MOISTURE LEVELS AND INSTABILITY WILL BE LESS THAN
SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT FRIDAY FOR COZ034.
&&
$$
UPDATE...GIMMESTAD
SHORT TERM...DANKERS
LONG TERM...BARJENBRUCH
AVIATION...GIMMESTAD
HYDROLOGY...BARJENBRUCH/DANKERS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
328 PM MDT WED MAY 20 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 328 PM MDT WED MAY 20 2015
CURRENT WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS INDICATING A
UPPER RIDGING BUILDING ACROSS THE STATE WITH A BROAD UPPER TROUGH
DIGGING ACROSS THE WEST COAST. WATER VAPOR IMAGERY ALSO INDICATING
AN EMBEDDED SHORT WAVE LIFTING OUT ACROSS THE SOUTHERN GREAT BASIN
WITH ANOTHER ONE ROUNDING THE BASE OF THE TROUGH ACROSS THE SOUTHERN
CALIF COAST ATTM. WARMING ALOFT AND MOIST LOW LEVEL UPSLOPE KEEPING
LOW CLOUDS TRAPPED AND COOL TEMPERATURES IN THE 40S AND 50S ACROSS
THE EASTERN PLAINS AT THIS TIME. REGIONAL SATELLITE AND RADAR DATA
INDICATING INSOLATION ACROSS THE HIGHER TERRAIN TERRAIN WEST OF THE
FRONT RANGE IS HELPING TO DEVELOP ISOLATED SHOWERS AND A FEW
EMBEDDED THUNDERSTORMS THROUGH THE EARLY AFTERNOON...WITH THE BEST
COVERAGE ACROSS THE NORTHERN AND CENTRAL MTS.
TONIGHT...TRANSITORY UPPER RIDGE CONTINUES TO BUILD ACROSS THE STATE
WITH THE PASSING GREAT BASIN EMBEDDED WAVE HELPING TO DEVELOP
CONVECTION THROUGH THE LATE EVENING HOURS...MAINLY OVER THE HIGHER
TERRAIN. LATEST NAM...GFS AND EC ARE BULLISH WITH BRINGING SHOWERS
ACROSS THE STABLE I-25 CORRIDOR...AND HAVE STAYED CLOSER TO THE HRRR
AND RAP WHICH KEEPS BEST CHANCES OF GENERALLY LIGHT RAIN ACROSS EL
PASO COUNTY. MODEL SOUNDINGS INDICATING CLOUDS TO LOWER ACROSS THE
PLAINS AGAIN OVERNIGHT...WITH FOG AND PATCHY DRIZZLE POSSIBLE ALONG
AND WEST OF THE I-25 CORRIDOR.
THURSDAY...SOUTHERLY FLOW ALOFT INCREASES THROUGH THE DAY AS THE
WEST COAST SYSTEM SLOWLY MOVES EAST. LATEST MODELS ARE A TAD SLOWLY
WITH THE SOUTHERN CALIF SHORT WAVE LIFTING OUT ACROSS THE DESERT
SOUTHWEST AND INTO THE ROCKIES...WHICH MAY DELAY THE
ONSET...COVERAGE AND INTENSITY OF SHOWERS AND THUNDERSTORMS ACROSS
THE AREA. AT ANY RATE...WILL SEE SHOWERS AND STORMS DEVELOPING
ACROSS THE HIGHER TERRAIN THROUGH THE AFTERNOON WITH STORMS MOVING
ACROSS THE ADJACENT PLAINS THROUGH THE LATE AFTERNOON AND EARLY
EVENING. SLOWER MOVEMENT OF THE SYSTEM LOOKS TO HINDER MIXING ACROSS
THE EASTERN PLAINS...WITH LOW CLOUDS SLOWLY LIFTING THROUGH THE LATE
MORNING AND AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 PM MDT WED MAY 20 2015
THURSDAY NIGHT AND FRIDAY...AN UPPER LEVEL STORM SYSTEM ACROSS THE
SOUTHWEST US IS FORECAST TO EJECT A RATHER STRONG SHORTWAVE TROUGH
INTO COLORADO. SURFACE FLOW FROM THE SOUTHEAST WITH BRING IN A DEEP
LAYER OF MOISTURE...WHICH WILL BE LIFTED BY THE TERRAIN AND
SHORTWAVE DYNAMICS TO PRODUCE ANOTHER EPISODE OF WIDESPREAD
MODERATE...AND LOCALLY HEAVY RAINFALL TO THE EASTERN MOUNTAINS AND
PLAINS. THE SHOWERS AND STORMS ARE DEPICTED BY THE GFS AND NAM TO
MAINLY OCCUR DURING THE FIRST HALF OF THURSDAY NIGHT...AND QUICKLY
SPREAD NORTH AND EAST DURING THE OVERNIGHT. A FEW LIGHTNING STRIKES
ARE POSSIBLE ACROSS THE CWA WITH ELEVATED INSTABILITY...HOWEVER
SEVERE WEATHER IS UNLIKELY THROUGH THURSDAY NIGHT. GFS IS MORE HEAVY
HANDED WITH PRECIPITATION ACROSS THE I-25 AND EASTERN MOUNTAINS THAN
THE NAM ON THE LATEST RUNS. MORE THAN AN INCH OF RAIN IS POSSIBLE
OVER THE EASTERN HALF OF THE CWA...WITH LOCALLY HIGHER AMOUNTS. WITH
SATURATED GROUND...THE POTENTIAL FOR FLASH FLOODING AND FLOODING IS
THERE. RIVERS AND LARGE CREEKS MAY ALSO EXPERIENCE MORE EROSION
ISSUES. SNOW LEVELS WILL REMAIN HIGH...WITH SEVERAL INCHES OF SNOW
POSSIBLE THROUGH FRIDAY MORNING ABOVE 10 KFT.
IN THE WAKE OF THE SHORTWAVE...SINKING MOTION AND DRYING WILL OCCUR.
MODELS ARE HINTING AT A DRY LINE ACROSS THE FAR EASTERN
PLAINS...WHICH COULD SPARK STRONG TO SEVERE STORMS NEAR THE KANSAS
BORDER. CAPES OVER 1000 J/KG AND 0-6 KM BULK SHEARS ABOVE 50 KNOTS
COULD CAUSE SOME STORM ROTATION. ELSEWHERE ON FRIDAY...ISOLATED
SHOWERS AND STORMS WILL OCCUR ACROSS THE MOUNTAINS FRIDAY AFTERNOON
AND DISSIPATE FRIDAY EVENING.
SATURDAY...THE MAIN UPPER SYSTEM WILL MIGRATE THROUGH THE GREAT
BASIN...WITH SOUTH-SOUTHWEST FLOW ACROSS THE CWA. ISOLATED TO
SCATTERED SHOWERS AND STORMS MAY DEVELOP ACROSS THE MOUNTAINS AND
HIGH VALLEYS...AND THE DRY LINE IS FORECAST TO BE ACROSS THE EASTERN
COUNTIES AGAIN...WITH A RISK OF STRONG TO MARGINALLY SEVERE STORMS
DURING THE AFTERNOON AND EVENING.
SUNDAY AND MONDAY...THE NEXT SYSTEM WILL MOVE ACROSS THE ROCKIES
SUNDAY INTO MONDAY. A WEAK COLD FRONT WILL PUSH THROUGH THE PLAINS
SUNDAY MORNING BRINGING MOISTURE INTO THE REGION. AN UPPER
DISTURBANCE WILL BRING SOME SHOWERS AND STORM TO THE AREA...LASTING
INTO MONDAY AFTERNOON.
TUESDAY AND WEDNESDAY...A MODEST RIDGE MAY BUILD INTO THE
AREA...PROVIDING SOME SUNSHINE...AND ONLY THE POSSIBILITY OF
AFTERNOON AND EVENING ISOLATED SHOWERS AND STORMS. -TLM-
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 328 PM MDT WED MAY 20 2015
MVFR CONDITIONS EXPECTED TO PERSIST AT COS AND PUB WITH MOIST LOW
LEVEL UPSLOPE KEEPING CLOUDS IN PLACE. COULD SEE -SHRA AND ISOLD
-TRSA OVER THE HIGHER TERRAIN WEST OF THE TERMINALS...THOUGH DOES
NOT LOOK TO AFFECT THE TERMINALS ATTM. EXPECTING IFR AND LOCAL LIFR
CONDITIONS TO REDEVELOP OVERNIGHT...WITH BR/FG AND DZ
POSSIBLE...ESPECIALLY AT COS. MVFR CONDITIONS EXPECTED AFT 16Z WITH
POSSIBLE SHOWERS AND STORMS DEVELOPING ACROSS THE HIGHER TERRAIN AFT
20Z.
VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS WITH
INCREASING COVERAGE OF SHOWERS AND STORMS ACROSS THE AREA AFT 18Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MW
LONG TERM...TM
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1049 PM EDT THU MAY 21 2015
.SYNOPSIS...
FAST-MOVING LOW PRESSURE WILL BRING A PERIOD OF LIGHT RAIN TO
RHODE ISLAND AND SOUTHEAST MASSACHUSETTS TONIGHT INTO FRIDAY
MORNING. THEN A COLD FRONT MAY TRIGGER AN ISOLATED SHOWER LATE
FRIDAY AFTERNOON INTO EARLY EVENING. BEHIND THIS FRONT...FROST AND
MAYBE EVEN RECORD-BREAKING COLD...IS POSSIBLE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE WILL BRING ABOUT DRY WEATHER
THROUGH MOST OF MONDAY. WARMER BUT MORE UNSETTLED WEATHER IS
EXPECTED NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
10 PM UPDATE...
DESPITE RADAR RETURNS OVER BID/MVY AND ACK LOW LEVEL DRY AIR AS
SEEN ON THE 00Z OKX SOUNDING CONTINUES TO EVAPORATE ANY RAINFALL
BEFORE REACHING THE SURFACE ACROSS THIS AREA. EVENTUALLY BOUNDARY
LAYER WILL SATURATE AND RAIN WILL REACH THE GROUND ALONG THE SOUTH
COAST INCLUDING CAPE COD AND THE ISLANDS THE SECOND HALF OF THE
NIGHT INTO EARLY FRI MORNING.
AS FOR MODEL GUIDANCE...12Z ECMWF/18Z RUNS OF GFS AND NAM/21Z SREF
AND 12Z NMM AND ARW ALL BRING NORTHWEST PORTION OF RAIN SHIELD
INTO THE BOSTON-PROVIDENCE 06Z-12Z...ALBEIT VERY LIGHT RAIN WITH
STEADIER RAIN CONFINED TO IMMEDIATE SOUTH COAST INCLUDING CAPE COD
AND ISLANDS. AT 00Z RADAR AND SATELLITE TRENDS SUPPORT THIS
SCENARIO. LATEST RUNS OF THE HRRR AND RAP ARE FARTHER SOUTHEAST.
NONETHELESS CURRENT FORECAST CAPTURES THIS THEME WITH BULK OF RAIN
ALONG THE SOUTH COAST WITH MUCH LIGHTER RAIN NORTHWARD INTO
PROVIDENCE- BOSTON CORRIDOR. ALL OTHER FORECAST PARAMETERS ON
TRACK AS WELL...THUS LITTLE IF ANY CHANGES WITH THIS FORECAST
UPDATE. EARLIER DISCUSSION BELOW.
==================================================================
TONIGHT...
NOT MUCH CHANGE FROM PREVIOUS THINKING. NORTHERN STREAM SHORTWAVE
ENERGY WILL ARRIVE LATER TONIGHT. THIS FEATURE WILL SPAWN A LATE
SEASON COASTAL LOW WAVE OVER THE SOUTHEAST STATES...THAT WILL
TRACK NEAR OR JUST SOUTHEAST OF THE 40N/70W BENCHMARK BY FRIDAY
MORNING.
21/12Z GUIDANCE CONTINUES ITS EXCELLENT AGREEMENT ON STEADY
RAINFALL WORKING INTO SOUTHEAST MA AND PORTIONS OF RI OVERNIGHT.
THERE IS STILL SOME QUESTION HOW FAR WEST THE BACK EDGE OF THE
PRECIPITATION SHIELD WILL MAKE IT. THE 09Z SREF IS THE FARTHEST
WEST...WITH THE 12Z NAM THE FARTHEST EAST. STAYED WITH A MORE
MODERATE APPROACH...AS EVIDENCED BY THE GFS AND ECMWF SOLUTIONS.
SINCE THIS WILL BE A DEVELOPING COASTAL LOW...TIMING OF THE
DYNAMIC COMPONENTS COMING TOGETHER WILL BE CRUCIAL. WILL NEED TO
WATCH THIS ASPECT OF THIS STORM CLOSELY.
REGARDING CONVECTIVE POTENTIAL...MODEL SOUNDINGS ARE NOT FAVORABLE
FOR ANY SORT OF CONVECTION OVERNIGHT.
&&
.SHORT TERM /FRIDAY NIGHT/...
FRIDAY...
A 3-PART DAY WITH MORNING RAINS LIKELY OVER RI AND SOUTHEAST
MA...POSSIBLY NORTHWARD TO BOSTON. DRIER WEATHER...ALONG WITH
MORE SUNSHINE...BRIEFLY DEVELOPS MID TO LATE MORNING AS COASTAL
LOW PRESSURE MOVES FARTHER OFFSHORE.
ANOTHER MID-LEVEL SHORTWAVE IS STILL EXPECTED TO MOVE THROUGH
SOUTHERN NEW ENGLAND FRIDAY AFTERNOON. COMBINED WITH AN
APPROACHING COLD FRONT...THERE SHOULD BE ENOUGH OF A TRIGGER TO
GENERATE SCATTERED SHOWERS ACROSS SOUTHERN NEW ENGLAND...MAINLY
ACROSS EASTERN MA. UNSEASONABLY STRONG COLD POOL ALOFT WILL ALSO
MEAN FAIRLY STEEP LAPSE RATES. THE BIG QUESTION WHICH REMAINS TO
BE ANSWERED WILL BE THE AMOUNT OF AVAILABLE MOISTURE. JUST ABOUT
ALL OF THE GUIDANCE REMAINS VERY DRY ABOVE 10 KFT. THUS CANNOT
COMPLETELY RULE OUT THE POSSIBILITY OF ISOLATED THUNDERSTORMS.
SHOULD ANY THUNDERSTORMS DEVELOP...SMALL HAIL WOULD BE A RISK IN
THE STRONGER CELLS.
FRIDAY NIGHT...
CONFIDENT WITH THE COLD FRONT PUSHING OFFSHORE THAT COLD AIR
ADVECTION WILL BE IN FULL SWING INTO SATURDAY MORNING. PROBABLY
LOOKING AT TEMPERATURES COLD ENOUGH TO WARRANT FROST ADVISORIES
ACROSS PORTIONS OF WESTERN MA...AGAIN. AS PREVIOUSLY MENTIONED...
THERE IS STILL AN ISSUE WITH WINDS. STILL EXPECTING A STEADY
NORTHWEST WIND...WHICH WOULD BE ENOUGH TO KEEP THE SURFACE LAYER
MIXED...AND PRECLUDE WIDESPREAD FROST DEVELOPMENT. WILL NEED TO
KEEP AN EYE ON THIS POTENTIAL. WILL BE CLOSE TO RECORD LOWS FOR A
FEW LOCATIONS /SEE THE CLIMATE SECTION BELOW/.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- UNSEASONABLY COOL SATURDAY
- FROST / FREEZE HEADLINES LIKELY FOR SATURDAY MORNING
- SEASONABLE AND DRY FOR SUNDAY
- BEGINNING MEMORIAL DAY...A WET-WEATHER PATTERN BEGINS TO EMERGE
- COULD REMAIN SEASONABLE AND WET THROUGH THE REMAINDER OF THE WEEK
*/ DISCUSSION...
CONFIDENT WITH THE COLD FRONT PUSHING OFFSHORE FRIDAY NIGHT THAT
COLD AIR ADVECTION WILL BE IN FULL SWING INTO SATURDAY MORNING.
BREEZY NW FLOW REARWARD OF THE PIVOTING VORTEX THRU N NEW ENGLAND
WILL USHER AN ANOMALOUSLY COLD AIRMASS S ALOFT. EXPECT WIDESPREAD
FROST/FREEZE HEADLINES ACROSS THE INTERIOR WITH THE BIGGEST IMPACT
OVER N/W PORTIONS OF MA. BUT AGREE WITH PREVIOUS FORECASTER THINKING
THAT THE BREEZY NW-FLOW COULD MITIGATE FROST DEVELOPMENT DESPITE
COLD TEMPERATURES. WILL BE CLOSE TO RECORD LOWS /SEE THE CLIMATE
SECTION BELOW/. COLD AIRMASS LINGERS AS HIGH PRESSURE BUILDS S OF
NEW ENGLAND. COOL AND DRY FOR SATURDAY. MORE SEASONABLE SUNDAY WITH
RETURN S-FLOW.
BEGINNING MEMORIAL DAY AM LESS CONFIDENT WITH THE FORECAST. PACIFIC-
ORIGIN IMPULSES ROTATING THROUGH THE W-HALF OF THE CONUS INVOKE DOWN-
STREAM RIDGING INTO NEW ENGLAND. BERMUDA HIGH REAFFIRMS ROUND THE W-
PERIPHERY WHICH SW-FLOW PREVAILS. THE WARM-FRONTAL LEADING EDGE OF
WARM-MOIST AIR WILL BE A FOCUS FOR WET-WEATHER AS PACIFIC IMPULSES
EJECT E THROUGH RIDGE PATTERN. COMBINATION OF ISENTROPIC ASCENT
BENEATH DIFFLUENCE ALOFT ALLOWING FOR BROADSCALE LIFT...CAN NOT RULE
OUT SHOWERS AROUND MONDAY - TUESDAY. FEEL BETTER CHANCES ARE N/W
AWAY FROM THE ANTICYCLONIC FLOW / DRY AIR AND TOWARDS MORE FAVORABLE
DYNAMICS.
FOR THE REST OF THE WEEK ENSEMBLE AND DETERMINISTIC GUIDANCE SUGGEST
A FLAT-FLOW REGIME ACROSS THE CONUS THROUGH WHICH PACIFIC-ORIGIN
IMPULSES PREVAIL. CONSIDERING THE OFFSHORE BERMUDA HIGH AND A VORTEX
PREVAILING ACROSS CANADA...MAY BE DEALING WITH A MORE ACTIVE PATTERN
AS THE WARM-MOIST FLOW IS STRETCHED ACROSS THE NE CONUS
UNDERGOING LIFT AND ENHANCEMENT AS MID-LEVEL IMPULSES TRANSLATE
THROUGH THE REGION. UNCERTAINTY AS ANY WOBBLE IN THE FLOW PATTERN
BETWEEN THE VORTEX N AND THE BERMUDA HIGH S WOULD MODIFY THE
CONVERGENT FLOW. GFS SUGGESTS A +1 SD OF H925 TEMPERATURES FOR
NEXT WEEK. IF +2 IT WOULD BE MORE LIKELY THAT THE CONVERGENT FLOW
WOULD BE N AND W WITH S NEW ENGLAND WARMER AND DRY BENEATH THE
RIDGE. WITH A CONSENSUS BLEND...WILL KEEP IT SEASONABLE WITH
SLIGHT CHANCE TO CHANCE POPS. ECHOING THE POINT MADE BY THE
PREVIOUS FORECASTER...COULD FIND OURSELVES WITHIN THE STEERING
FLOW OF UPSTREAM MCS/S. CONTINUED SIGNALS OF A CUTOFF LOW WOBBLING
ACROSS THE NW-ATLANTIC. WILL HAVE TO KEEP AN EYE ON THAT.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...
10 PM UPDATE...NO CHANGES FROM 00Z TAFS. EARLIER DISCUSSION BELOW.
==================================================================
THROUGH TONIGHT...HIGH CONFIDENCE.
MAINLY VFR. BEST CHANCE FOR MVFR AT ACK/MVY AND POSSIBLY PERIODS
OF MVFR AT HYA/FMH. THIS WILL MAINLY BE IN AN AREA OF RAIN WHICH
WILL MOVE IN OFF THE SOUTH COAST BETWEEN 01Z AND 06Z. HEAVIEST
ALONG THE ISLANDS.
FRIDAY...MORNING -RA EXITS SE MA. DRY LATE MORNING INTO EARLY
AFTERNOON. THEN A COLD FRONT WILL LIKELY TRIGGER SCT -SHRA FROM
LATE AFTERNOON INTO EARLY EVENING. LOW RISK OF SMALL HAIL IN MORE
ROBUST SHRA WITH ISOLATED TSRA. OVERALL VFR. MODERATE CONFIDENCE.
FRIDAY NIGHT...HIGH CONFIDENCE VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SAT...MODERATE CONFIDENCE. MAINLY VFR. BUT SOME PERIODS OF MVFR
POSSIBLE IN OCCASIONAL SHOWERS/FOG.
SUN AND MON...MODERATE CONFIDENCE. A BACKDOOR COLD FRONT WILL ALLOW
WINDS TO SHIFT TO THE E AT MOST TERMINALS THROUGH THIS PERIOD.
CONDITIONS START VFR...BUT SOME MVFR/IFR POSSIBLE SUN NIGHT INTO MON
AS STRATUS MOVES OFF THE E COAST.
TUE..MODERATE CONFIDENCE. MAINLY VFR...HOWEVER ONCE AGAIN A COLD
FRONT MOVES THROUGH WITH SHOWERS AND ISOLATED THUNDERSHOWERS. THIS
BRINGS ABOUT THE CHANCE FOR PERIODIC MVFR/IFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
RAIN OVERSPREADS THE SOUTHERN WATERS OVERNIGHT AS LOW PRES TRACKS
NEAR OR JUST SOUTH OF 40N/70W BENCHMARK. SOME UNCERTAINTY ON
NORTHERN EXTENT OF RAIN SHIELD. STEADY RAINFALL GIVES WAY TO
SCATTERED SHOWERS FRIDAY AFTERNOON AND EVENING AS A COLD FRONT
APPROACHES FROM THE WEST. GUSTY NORTHWEST WINDS DEVELOP BEHIND
THIS FRONT...WITH THE POTENTIAL FOR GUSTS UP TO 30 KT IN PLACES.
SMALL CRAFT ADVISORIES MAY BE NEEDED SOMETIME FRIDAY NIGHT INTO
SATURDAY...ESPECIALLY ACROSS THE OUTER COASTAL WATERS.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SAT INTO SUN...HIGH CONFIDENCE. MAINLY QUIET BOATING WEATHER THROUGH
THE PERIOD...ALTHOUGH WINDS MAY APPROACH 25 KT OUT OF THE S ON SAT
NEAR CAPE COD AND THE ISLANDS. OTHERWISE...SHOWERS AND AN ISOLATED
THUNDERSHOWER POSSIBLE.
MON AND TUE...HIGH CONFIDENCE. E WINDS ON MON WILL GIVE WAY TO A
RETURN TO S WINDS EARLY TUE WITH ANOTHER ROUND OF SHOWERS. LATE TUE
WINDS SHIFT TO THE W-NW. CONDITIONS MAINLY BELOW SMALL CRAFT
ADVISORY THRESHOLDS.
&&
.CLIMATE...
RECORD LOWS FOR MAY 23RD...
BOSTON - 40 /1967/
HARTFORD - 37 /1976/
PROVIDENCE - 40 /1950/
WORCESTER - 32 /1929/
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/DOODY
NEAR TERM...NOCERA
SHORT TERM...BELK
LONG TERM...SIPPRELL
AVIATION...BELK/SIPPRELL
MARINE...BELK/SIPPRELL
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
953 PM EDT THU MAY 21 2015
.SYNOPSIS...
FAST-MOVING LOW PRESSURE WILL BRING A PERIOD OF LIGHT RAIN TO
RHODE ISLAND AND SOUTHEAST MASSACHUSETTS TONIGHT INTO FRIDAY
MORNING. THEN A COLD FRONT MAY TRIGGER AN ISOLATED SHOWER LATE
FRIDAY AFTERNOON INTO EARLY EVENING. BEHIND THIS FRONT...FROST AND
MAYBE EVEN RECORD-BREAKING COLD...IS POSSIBLE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE WILL BRING ABOUT DRY WEATHER
THROUGH MOST OF MONDAY. WARMER BUT MORE UNSETTLED WEATHER IS
EXPECTED NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
10 PM UPDATE...
DESPITE RADAR RETURNS OVER BID/MVY AND ACK LOW LEVEL DRY AIR AS
SEEN ON THE 00Z OKX SOUNDING CONTINUES TO EVAPORATE ANY RAINFALL
BEFORE REACHING THE SURFACE ACROSS THIS AREA. EVENTUALLY BOUNDARY
LAYER WILL SATURATE AND RAIN WILL REACH THE GROUND ALONG THE SOUTH
COAST INCLUDING CAPE COD AND THE ISLANDS THE SECOND HALF OF THE
NIGHT INTO EARLY FRI MORNING.
AS FOR MODEL GUIDANCE...12Z ECMWF/18Z RUNS OF GFS AND NAM/21Z SREF
AND 12Z NMM AND ARW ALL BRING NORTHWEST PORTION OF RAIN SHIELD
INTO THE BOSTON-PROVIDENCE 06Z-12Z...ALBEIT VERY LIGHT RAIN WITH
STEADIER RAIN CONFINED TO IMMEDIATE SOUTH COAST INCLUDING CAPE COD
AND ISLANDS. AT 00Z RADAR AND SATELLITE TRENDS SUPPORT THIS
SCENARIO. LATEST RUNS OF THE HRRR AND RAP ARE FARTHER SOUTHEAST.
NONETHELESS CURRENT FORECAST CAPTURES THIS THEME WITH BULK OF RAIN
ALONG THE SOUTH COAST WITH MUCH LIGHTER RAIN NORTHWARD INTO
PROVIDENCE- BOSTON CORRIDOR. ALL OTHER FORECAST PARAMETERS ON
TRACK AS WELL...THUS LITTLE IF ANY CHANGES WITH THIS FORECAST
UPDATE. EARLIER DISCUSSION BELOW.
==================================================================
TONIGHT...
NOT MUCH CHANGE FROM PREVIOUS THINKING. NORTHERN STREAM SHORTWAVE
ENERGY WILL ARRIVE LATER TONIGHT. THIS FEATURE WILL SPAWN A LATE
SEASON COASTAL LOW WAVE OVER THE SOUTHEAST STATES...THAT WILL
TRACK NEAR OR JUST SOUTHEAST OF THE 40N/70W BENCHMARK BY FRIDAY
MORNING.
21/12Z GUIDANCE CONTINUES ITS EXCELLENT AGREEMENT ON STEADY
RAINFALL WORKING INTO SOUTHEAST MA AND PORTIONS OF RI OVERNIGHT.
THERE IS STILL SOME QUESTION HOW FAR WEST THE BACK EDGE OF THE
PRECIPITATION SHIELD WILL MAKE IT. THE 09Z SREF IS THE FARTHEST
WEST...WITH THE 12Z NAM THE FARTHEST EAST. STAYED WITH A MORE
MODERATE APPROACH...AS EVIDENCED BY THE GFS AND ECMWF SOLUTIONS.
SINCE THIS WILL BE A DEVELOPING COASTAL LOW...TIMING OF THE
DYNAMIC COMPONENTS COMING TOGETHER WILL BE CRUCIAL. WILL NEED TO
WATCH THIS ASPECT OF THIS STORM CLOSELY.
REGARDING CONVECTIVE POTENTIAL...MODEL SOUNDINGS ARE NOT FAVORABLE
FOR ANY SORT OF CONVECTION OVERNIGHT.
&&
.SHORT TERM /FRIDAY NIGHT/...
FRIDAY...
A 3-PART DAY WITH MORNING RAINS LIKELY OVER RI AND SOUTHEAST
MA...POSSIBLY NORTHWARD TO BOSTON. DRIER WEATHER...ALONG WITH
MORE SUNSHINE...BRIEFLY DEVELOPS MID TO LATE MORNING AS COASTAL
LOW PRESSURE MOVES FARTHER OFFSHORE.
ANOTHER MID-LEVEL SHORTWAVE IS STILL EXPECTED TO MOVE THROUGH
SOUTHERN NEW ENGLAND FRIDAY AFTERNOON. COMBINED WITH AN
APPROACHING COLD FRONT...THERE SHOULD BE ENOUGH OF A TRIGGER TO
GENERATE SCATTERED SHOWERS ACROSS SOUTHERN NEW ENGLAND...MAINLY
ACROSS EASTERN MA. UNSEASONABLY STRONG COLD POOL ALOFT WILL ALSO
MEAN FAIRLY STEEP LAPSE RATES. THE BIG QUESTION WHICH REMAINS TO
BE ANSWERED WILL BE THE AMOUNT OF AVAILABLE MOISTURE. JUST ABOUT
ALL OF THE GUIDANCE REMAINS VERY DRY ABOVE 10 KFT. THUS CANNOT
COMPLETELY RULE OUT THE POSSIBILITY OF ISOLATED THUNDERSTORMS.
SHOULD ANY THUNDERSTORMS DEVELOP...SMALL HAIL WOULD BE A RISK IN
THE STRONGER CELLS.
FRIDAY NIGHT...
CONFIDENT WITH THE COLD FRONT PUSHING OFFSHORE THAT COLD AIR
ADVECTION WILL BE IN FULL SWING INTO SATURDAY MORNING. PROBABLY
LOOKING AT TEMPERATURES COLD ENOUGH TO WARRANT FROST ADVISORIES
ACROSS PORTIONS OF WESTERN MA...AGAIN. AS PREVIOUSLY MENTIONED...
THERE IS STILL AN ISSUE WITH WINDS. STILL EXPECTING A STEADY
NORTHWEST WIND...WHICH WOULD BE ENOUGH TO KEEP THE SURFACE LAYER
MIXED...AND PRECLUDE WIDESPREAD FROST DEVELOPMENT. WILL NEED TO
KEEP AN EYE ON THIS POTENTIAL. WILL BE CLOSE TO RECORD LOWS FOR A
FEW LOCATIONS /SEE THE CLIMATE SECTION BELOW/.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
HIGHLIGHTS...
* RAIN SAT WITH WARM FRONT
* BACK DOOR COLD FRONT WILL BRING COOLER TEMPERATURES SUN AND MON
* COLD FRONT MAY BRING ANOTHER ROUND OF SHOWERS TOWARDS MIDWEEK
OVERVIEW AND MODEL PREFERENCES...
14.12Z MODEL GUIDANCE IS IN RATHER GOOD AGREEMENT IN SPITE OF THE
FACT THERE IS A TREND FROM A VERY AMPLIFIED WRN CONUS TO A RATHER
AMPLIFIED WRN ATLANTIC THROUGH THE LONG TERM. IN ESSENCE A RIDGE
WILL BE BUILDING ACROSS THE AREA INTO THE WEEKEND. THIS RIDGE THEN
BECOMES QUITE AMPLIFIED BUT ALSO RATHER ACUTE AS AN UPPER LVL
SHORTWAVE PHASES WITH CUTOFF LOW PRES WELL S OF NOVA SCOTIA. THIS
CREATES A BLOCKED FLOW REGIME WITH THE RIDGE REMAINING THE DOMINANT
FEATURE FOR NEW ENGLAND UNTIL A COLDER CANADIAN WAVE FLATTENS THE
RIDGE TOWARD THE MIDDLE PERIOD OF NEXT WEEK. GIVEN THERE IS FAIR
AGREEMENT HERE...FEEL THAT A BLEND OF LONG TERM OPERATIONAL GUIDANCE
WILL WORK AS A GOOD BASELINE FOR THIS FORECAST.
DETAILS...
SAT AND SAT NIGHT...THIS PERIOD IS MARKED BY THE SLOW PASSAGE OF
A SFC WARM FRONT FROM THE SW. AS THE WAVE ASSOCIATED WITH IT
PHASES WITH THE CUTOFF TO THE E...EXPECT THE FRONT TO SLOW
SOMEWHERE INVOF SRN NEW ENGLAND TO JUST OFFSHORE IN THE GULF OF
MAINE. TYPICAL SETUP HERE...WITH ISENTROPIC LIFT ON THE LEADING
EDGE OF THIS FRONT ALONG WITH INCREASED MOISTURE CONVERGENCE
YIELDING PWATS NEAR 1.5 INCHES OR NEARLY 2 STD DEVIATIONS ABOVE
MAY NORMALS. ABOVE THIS WARM FRONT...REASONABLY STEEP LAPSE RATES
OF ABOUT 6.0+ C/KM ALSO YIELD NEARLY 500-1000 J/KG ELEVATED CAPE
PER LATEST BUFKIT PROFILES. THEREFORE...DECENT SETUP FOR WARM
FRONTAL INSTABILITY SAT INTO SAT EVENING. MODEST SHEAR PROFILES AS
WELL...TYPICAL IN THESE WARM FRONTAL SETUPS. THEREFORE...WILL
CONTINUE TO INCLUDE THREAT FOR T- STORMS ALONG WITH SHOWERS UNTIL
DRY HIGH PRES ASSOCIATED WITH THE RIDGE FORCES THE F-GEN AXES
OFFSHORE. ONE STICKING POINT WOULD BE THE POSSIBILITY OF A REMNANT
MCS MOVING THROUGH IN THE MORNING...WHICH COULD PUT A DAMPER ON
AFTERNOON INSTABILITY IF THINGS DOWN SCOUR OUT QUICKLY ENOUGH.
SOMETHING TO MONITOR. TEMPS WILL BE DEPENDENT ON SUNSHINE...BUT
WITH ANY BREAKS COULD SEE HIGHS APPROACHING THE 80S.
SUN INTO MON...JUST IN CASE YOU FORGOT THAT WE LIVE IN NEW
ENGLAND AND IT/S STILL SPRING...WE WILL GET A STARK REMINDER IN
THE FORM OF YET ANOTHER BACKDOOR COLD FRONT WHICH WILL BEGIN TO
SLIDE OUT OF THE GULF OF MAINE SUN. THERE ARE STILL A FEW
QUESTIONS AS TO EXACTLY HOW FAR TO THE SW THIS FRONT ENDS UP
MAKING IT...BUT ITS LIKELY AT LEAST MOST OF ERN MA/RI AND PORTIONS
OF E CT WILL ONCE AGAIN SEE FALLING TEMPS AND SOME MARINE STRATUS.
DRY AIR ALOFT DOES SUGGEST THE POSSIBILITY OF DRIZZLE...BUT THERE
IS SOME QUESTION OF HOW MUCH LOW LVL MOISTURE WILL REMAIN GIVEN
THE DRY PUNCH THAT COMES IN AHEAD OF THE BACKDOOR FRONT. MODELS
LOOK A LITTLE TOO WARM...BUT THERE WILL LIKELY AT LEAST BE SOME
AREAS ON SUN THAT MAKE A RUN INTO THE 80S AHEAD OF THE FRONT. BUT
WILL LIKELY BE ADJUSTING THE REMAINING TEMPS FOR THE LATE
AFTERNOON SUN AND MON HIGHS DOWN.
TUE...ROBUST THETA-E RIDGE COINCIDENT WITH PWATS 3 STD DEVIATIONS
ABOVE NORMAL WILL SLIDE OVER NEW ENGLAND IN ADVANCE OF A FAIRLY
STRONG COLD FRONT. THE BIG QUESTION FOR INSTABILITY WILL BE HOW
MUCH WARM AIR WILL BE ALLOWED BACK INTO THE LOW LVLS AS THE
BACKDOOR COLD FRONT WASHES OUT. THERE IS REASONABLY GOOD AGREEMENT
THAT THE TIMING OF THIS FRONT IS PERFECT...RIGHT DURING PEAK
HEATING. AVAILABLE MODEL SOUNDINGS ARE SHOWING THIS UNCERTAINTY AS
WELL...KEEPING A MODEST INVERSION IN PLACE ACROSS MUCH OF THE
REGION WHICH IS KEEPING INSTABILITY PARAMETERS LOW. THERE IS SHEAR
THOUGH...SO WILL JUST HAVE TO KEEP AN EYE ON THIS FEATURE AS WE
GET CLOSER. IN ANY CASE...THE ROBUST MOISTURE AND LIFT SHOULD
YIELD SOME FAIRLY GOOD...ALBEIT BRIEF RAINFALL.
WED...THIS COLD FRONT WILL USHER IN HIGH PRES AND RATHER COOL
AIRMASS PER AVAILABLE GUIDANCE. WILL LIKELY SEE A PERIOD WHERE
TEMPS ARE ONCE AGAIN NEAR OR EVEN BELOW NORMAL. DO ALSO NOTE A
FAIRLY ROBUST PRES GRADIENT ON WED...SO DEPENDING ON
RAINFALL...WITH VERY DRY AIRMASS MOVING IN MAY NEED TO MONITOR FOR
YET ANOTHER DAY OF ELEVATED FIRE WEATHER.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...
10 PM UPDATE...NO CHANGES FROM 00Z TAFS. EARLIER DISCUSSION BELOW.
==================================================================
THROUGH TONIGHT...HIGH CONFIDENCE.
MAINLY VFR. BEST CHANCE FOR MVFR AT ACK/MVY AND POSSIBLY PERIODS
OF MVFR AT HYA/FMH. THIS WILL MAINLY BE IN AN AREA OF RAIN WHICH
WILL MOVE IN OFF THE SOUTH COAST BETWEEN 01Z AND 06Z. HEAVIEST
ALONG THE ISLANDS.
FRIDAY...MORNING -RA EXITS SE MA. DRY LATE MORNING INTO EARLY
AFTERNOON. THEN A COLD FRONT WILL LIKELY TRIGGER SCT -SHRA FROM
LATE AFTERNOON INTO EARLY EVENING. LOW RISK OF SMALL HAIL IN MORE
ROBUST SHRA WITH ISOLATED TSRA. OVERALL VFR. MODERATE CONFIDENCE.
FRIDAY NIGHT...HIGH CONFIDENCE VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SAT...MODERATE CONFIDENCE. MAINLY VFR. BUT SOME PERIODS OF MVFR
POSSIBLE IN OCCASIONAL SHOWERS/FOG.
SUN AND MON...MODERATE CONFIDENCE. A BACKDOOR COLD FRONT WILL ALLOW
WINDS TO SHIFT TO THE E AT MOST TERMINALS THROUGH THIS PERIOD.
CONDITIONS START VFR...BUT SOME MVFR/IFR POSSIBLE SUN NIGHT INTO MON
AS STRATUS MOVES OFF THE E COAST.
TUE..MODERATE CONFIDENCE. MAINLY VFR...HOWEVER ONCE AGAIN A COLD
FRONT MOVES THROUGH WITH SHOWERS AND ISOLATED THUNDERSHOWERS. THIS
BRINGS ABOUT THE CHANCE FOR PERIODIC MVFR/IFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
RAIN OVERSPREADS THE SOUTHERN WATERS OVERNIGHT AS LOW PRES TRACKS
NEAR OR JUST SOUTH OF 40N/70W BENCHMARK. SOME UNCERTAINTY ON
NORTHERN EXTENT OF RAIN SHIELD. STEADY RAINFALL GIVES WAY TO
SCATTERED SHOWERS FRIDAY AFTERNOON AND EVENING AS A COLD FRONT
APPROACHES FROM THE WEST. GUSTY NORTHWEST WINDS DEVELOP BEHIND
THIS FRONT...WITH THE POTENTIAL FOR GUSTS UP TO 30 KT IN PLACES.
SMALL CRAFT ADVISORIES MAY BE NEEDED SOMETIME FRIDAY NIGHT INTO
SATURDAY...ESPECIALLY ACROSS THE OUTER COASTAL WATERS.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SAT INTO SUN...HIGH CONFIDENCE. MAINLY QUIET BOATING WEATHER THROUGH
THE PERIOD...ALTHOUGH WINDS MAY APPROACH 25 KT OUT OF THE S ON SAT
NEAR CAPE COD AND THE ISLANDS. OTHERWISE...SHOWERS AND AN ISOLATED
THUNDERSHOWER POSSIBLE.
MON AND TUE...HIGH CONFIDENCE. E WINDS ON MON WILL GIVE WAY TO A
RETURN TO S WINDS EARLY TUE WITH ANOTHER ROUND OF SHOWERS. LATE TUE
WINDS SHIFT TO THE W-NW. CONDITIONS MAINLY BELOW SMALL CRAFT
ADVISORY THRESHOLDS.
&&
.CLIMATE...
RECORD LOWS FOR MAY 23RD...
BOSTON - 40 /1967/
HARTFORD - 37 /1976/
PROVIDENCE - 40 /1950/
WORCESTER - 32 /1929/
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/DOODY
NEAR TERM...NOCERA
SHORT TERM...BELK
LONG TERM...SIPPRELL
AVIATION...BELK/SIPPRELL
MARINE...BELK/SIPPRELL
CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
749 PM EDT THU MAY 21 2015
.SYNOPSIS...
LOW PRESSURE PASSES SOUTH OF THE REGION TONIGHT. A COLD FRONT MOVES
ACROSS THE AREA LATE FRIDAY. HIGH PRESSURE BUILDS ACROSS THE AREA ON
SATURDAY AND SUNDAY. A WARM FRONT WILL THEN SLOWLY APPROACH FROM
THE SOUTHWEST FROM SUNDAY NIGHT INTO MONDAY NIGHT...AND SHOULD
LIFT THROUGH ON TUESDAY. HIGH PRESSURE WILL THEN REMAIN IN PLACE
OFF THE MID ATLANTIC COAST...WHILE A WEAK FRONTAL SYSTEM REMAINS
JUST TO THE WEST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 23Z...RADAR SHOWS LIGHT RAIN...MAINLY FALLING OVER LONG
ISLAND. SURFACE LOW PRESSURE IS LOCATED JUST OFF THE NORTHEAST
NORTH CAROLINA. GIVEN CURRENT PRESSURE FALLS...THE FORECAST TRACK IS
CONSISTENT WITH TRACKING THE LOW TO THE EAST OF THE 40/70
BENCHMARK. FOR THE MOST PART...THE RAIN WILL BE LIMITED TO LONG
ISLAND...THEN SOUTHEAST CT AND THE TWIN FORKS AS THE PRECIPITATION
FIELD PIVOTS AS THE LOW APPROACHES...MAINLY AFTER MIDNIGHT
TONIGHT. THE HRRR IS SHOWING AN AREA OF LIGHT RAIN MOVING IN FROM
PA. CURRENT RADAR MOSAIC OVER WESTERN PA DOES SHOW AN AREA OF
LIGHT RAIN...WITH AREAL COVERAGE INCREASING. HOW THE HRRR HANDLES
THIS AREA OF RAIN IS QUESTIONABLE...BUT DECIDED TO ADD SLIGHT
CHANCE POPS FOR ALL AREAS OUTSIDE THOSE EASTERN SECTIONS
PREVIOUSLY MENTIONED.
LOW PRESSURE DEVELOPS AND SLIDES SOUTHEAST OF THE AREA OVERNIGHT.
THE MAIN QUESTION WILL BE HOW FAR NORTH THE PRECIPITATION SHIELD
REACHES. AT THIS TIME...IT APPEARS THE BEST CHANCES FOR ANY RAIN
WILL BE ACROSS THE SOUTHERN HALF OF THE CWA...GENERALLY LONG
ISLAND...NYC AND INTO NJ. RAINFALL AMOUNTS APPEAR TO BE
LIGHT...WITH AROUND A TENTH OF AN INCH...TO POSSIBLY TWO TENTHS OF
AN INCH ACROSS FAR EASTERN SECTIONS WHERE THE BEST CHANCES OF RAIN
WILL BE. LITTLE TO NO RAINFALL IS EXPECTED ACROSS THE NORTHERN
HALF OF THE CWA.
MOST OF THE RAINFALL IS EXPECTED TO BE EAST OF THE REGION EARLY
FRIDAY MORNING.
OTHERWISE...EXPECT A CLOUDY NIGHT WITH TEMPERATURES FALLING INTO
THE 40S...EXCEPT THE NYC METRO...WHERE LOWER 50S ARE EXPECTED.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
MAINLY DRY WEATHER EXPECTED THROUGH THE MORNING...WITH MOSTLY
SUNNY SKIES. A COLD FRONT OUT AHEAD OF A DIGGING TROUGH APPROACHES
WHICH WILL ALLOW CLOUDS TO INCREASE ONCE AGAIN DURING THE
AFTERNOON. WILL CONTINUE TO KEEP SLIGHT CHANCE POPS IN THE
FORECAST WITH A FEW SHOWERS POSSIBLE JUST AHEAD OF OR WITH THE
COLD FRONT ITSELF. A GUSTY WEST-NORTHWEST FLOW IS EXPECTED FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT.
WEST FLOW AND BRIEF WARM AIR ADVECTION TOMORROW...WILL RESULT IN
NEAR TO PERHAPS SLIGHTLY ABOVE NORMAL TEMPERATURES IN THE 70 TO 75
DEGREE RANGE. LOWS FRIDAY NIGHT WILL BE COLD AS TEMPERATURES DROP
INTO THE UPPER 30S AND 40S.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COOL...DRY AND BREEZY CONDITIONS EXPECTED FOR SAT AS HIGH PRESSURE
BUILDS INTO THE REGION...WITH HIGHS ONLY IN THE MID AND UPPER 60S.
TEMPS SHOULD MODERATE TO NEAR OF SLIGHTLY ABOVE AVG LEVELS BY SUNDAY
AS THE HIGH MOVES TO THE EAST AND RETURN SW FLOW SETS UP...WITH
HIGHS IN THE 70S.
TIMING OF A WARM FRONTAL APPROACH AND ITS EVENTUAL PASSAGE SOMEWHAT
UNCERTAIN FOR EARLY NEXT WEEK. PER BLEND OF 00Z/12Z ECMWF...THINK
THE FRONT WILL HANG UP TO THE SW ON MON...BRINGING A GOOD CHANCE FOR
SHOWERS...THEN LIFT TO THE NE TUE MORNING. A WEAK LEE TROUGH SHOULD
REMAIN AFTER FROPA THAT SHOULD PROMOTE CHANCES FOR DIURNAL
SHOWERS/TSTMS ESPECIALLY FROM NYC NORTH/WEST FROM TUE THROUGH THU.
TEMPS NEAR AVG ON MON...WITH HIGHS IN THE 70S...SHOULD RISE TO ABOVE
AVG TUE-THU...WITH HIGHS GENERALLY 80-85 INLAND...AND 75-80 CLOSER
TO THE COAST.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
LOW PRES WILL PASS SOUTH AND EAST OF THE AREA TONIGHT INTO FRIDAY
MORNING. A COLD FRONT WILL PASS OVER THE TERMINALS LATE FRIDAY
AFTERNOON.
VFR THROUGH THE TAF PERIOD. BEST CHANCE FOR -RA THIS EVENING
CONTINUES TO BE AT FROM KJFK TO KISP. ANY -RA ENDS OVERNIGHT. CIGS
ON FRIDAY SHOULD BE SCT-BKN AROUND 6000 FT.
S/SSW FLOW AROUND 10 KT DIMINISHES OVERNIGHT. NW FLOW DEVELOPS
EARLY FRIDAY MORNING AND INCREASES DURING THE DAY. SUSTAINED
SPEEDS 10 TO 15 KT WITH GUSTS 22 TO 28 KT IN THE AFTERNOON. WINDS
COULD INCREASE SLIGHTLY BEHIND THE COLD FRONT PASSAGE LATE FRIDAY
AFTERNOON.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW PROBABILITY FOR CIGS TO DROP BELOW 3000
FT THROUGH MIDNIGHT.
KLGA FCSTER COMMENTS: -RA LIKELY STAYS SOUTH AND EAST OF THE
TERMINAL.
KEWR FCSTER COMMENTS: -RA LIKELY STAYS SOUTH AND EAST OF THE
TERMINAL.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: LOW PROBABILITY FOR CIGS TO DROP BELOW 3000
FT THROUGH MIDNIGHT.
.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.FRI NIGHT...NW GUSTS 20-25 KT EARLY...DIMINISHING LATE.
.SAT...VFR. W WINDS 10-20KT IN THE AFTN.
.SUN...VFR. WSW WINDS 15-25KT.
.MON...VFR TO START...THEN MVFR POSSIBLE INVOF A WARM FRONT. SHRA
POSSIBLE.
.TUE...PERIODS OF MVFR OR LOWER POSSIBLE WITH STRATUS AND FOG.
&&
.MARINE...
LOW PRESSURE APPROACHES AND TRACKS SOUTH AND EAST OF THE WATERS
TONIGHT. THIS LOW MOVES NORTHEAST AS A COLD FRONT APPROACHES FRIDAY
AFTERNOON. LIGHT NORTHERLY WINDS TONIGHT INTO FRIDAY MORNING TURN
TOWARD BACK TO THE WEST AND INCREASE DURING THE AFTERNOON. WINDS
WILL INCREASE WITH 25 TO PERHAPS 30 KT GUSTS NEAR SHORE LATE IN THE
AFTERNOON...ESPECIALLY NY HARBOR AND WESTERN LI SOUND. HAVE ISSUED A
SMALL CRAFT ADVISORY FOR ALL WATERS FOR FRIDAY AND FRIDAY NIGHT FOR
THE GUSTY WINDS. THINKING THAT SEAS WILL GENERALLY REMAIN BELOW 5
FT...HOWEVER CAN NOT RULE OUT A BRIEF PERIOD OF 5 FT SEAS WITH THE
HIGHER GUSTS.
COULD SEE SOME WIND GUSTS CLOSE TO 25 KT ON THE ERN OCEAN WATERS
DURING THE DAY ON SAT...BUT MORE LIKELY TIME FRAME FOR SCA CONDS
WILL COME FROM SAT NIGHT INTO SUNDAY...AS PERSISTENT SW FLOW 15-20
KT PUSHES SEAS AS HIGH AS 5 FT ON THE OUTERMOST AND EASTERN OCEAN
WATERS.
&&
.FIRE WEATHER...
DRY WEATHER RETURNS FRIDAY. WEATHER CONDITIONS ON FRIDAY MAY STILL
BE CONDUCIVE TO GROWTH/SPREAD OF ANY FIRES THAT DEVELOP. RH VALUES
ARE EXPECTED TO FALL THROUGH THE DAY FRIDAY...FALLING TO NEAR 30
PERCENT...AND W-NW WINDS WILL GUST TO 25-30 MPH DURING THE
AFTERNOON. KBDI IS IN THE 100S ACROSS MOST OF SRN CT AND THE LOWER
HUDSON VALLEY AND IN THE 200S ACROSS NYC METRO AND LONG ISLAND...BUT
MAY NOT BE FULLY REPRESENTATIVE OF THE PERSISTENT DRY CONDITIONS
THAT HAVE BEEN IN PLACE. WITH MARGINAL RH VALUES...WILL HOLD OFF ON
ANY RED FLAG HEADLINES AND CONTINUE TO KEEP MENTION IN THE HWO.
SAT COULD ALSO BE A DAY OF CONCERN ESPECIALLY FOR NYC
METRO...SOUTHERN CT AND LONG ISLAND...WITH MIN RH AGAIN IN THE 20S
AND NW-W WINDS GUSTING TO 20-25 MPH.
&&
.HYDROLOGY...
THERE IS THE POTENTIAL FOR BETWEEN ONE AND TWO TENTHS OF AN INCH OF
RAIN NEAR THE COAST. NORTHERN ZONES SUCH AS THE LOWER HUDSON VALLEY
AND SRN CT...QPF WOULD RANGE FROM A TRACE TO MAYBE A TENTH OF AN
INCH.
QPF WITH AN APPROACHING WARM FRONT SHOULD RANGE FROM 1/4 TO 1/2
INCH...WITH LOCALLY HIGHER AMTS OVER 1/2 INCH POSSIBLE. DIURNAL
SHOWERS/TSTMS TUE THROUGH THU COULD ALSO BRING LOCALLY SIGNIFICANT
AMTS FROM NYC NORTH/WEST.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ330-335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...BC/GOODMAN
NEAR TERM...BC
SHORT TERM...BC
LONG TERM...GOODMAN
AVIATION...DS
MARINE...BC/GOODMAN
FIRE WEATHER...
HYDROLOGY...BC/GOODMAN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
930 AM EDT WED MAY 20 2015
.DISCUSSION...
CURRENT...TAILEND OF A FRONT JUST SKIRTING ST JOHN AND FLAGLER
COUNTIES AND APPROACHING NORTHEAST VOLUSIA COUNTY. DIURNAL CUMULUS
FIELD SHOULD START FORMING WITHIN THE HOUR WITH THE INCREASING
TEMPERATURES AND THE INCREASING MOISTURE PER THE MORNING CAPE
CANAVERAL SOUNDING. THE VERTICAL WIND PROFILER(S) AT KSC WERE
DETECTING SOUTHWEST TO WEST WINDS TO 10 KNOTS THROUGH ABOUT 4000
FEET THEN A QUICK SHIFT TO THE NORTH THEN NORTHEAST THROUGH ABOUT
10000 FEET. THE LOW LEVEL SOUTHWEST TO WEST WIND COULD DELAY THE
EAST COAST SEA BREEZE BY AN HOUR OR TWO THIS AFTERNOON. LIGHT NORTH
TO SOUTH WINDS ABOVE THE BOUNDARY LAYER AN INDICATOR OF A SLOW SOUTH
TO SOUTHWEST STORM MOTION THIS AFTERNOON. COOLER TEMPERATURES
ALOFT...-10C AT CAPE CANAVERAL AND -8C AT JACKSONVILLE...A GOOD
INDICATOR FOR STRONG WIND GUSTS AND HAIL IN ANY OF THE STRONGER
STORMS THAT DEVELOP THIS AFTERNOON. LATEST HRRR MODEL RUN SUGGESTING
SEA BREEZES FORMING EARLY AFTERNOON AND MOVING SLOWLY INLAND AS IT
PUSHES AGAINST THE PREVAILING LOW LEVEL SOUTHWEST TO WEST WINDFLOW.
THE HRRR ALSO IS SUGGESTING THE BEST TIME FRAME FOR STORMS ALONG A
LINE FROM FROM AROUND DAYTONA BEACH TO OKEECHOBEE COUNTY WITH A SLOW
SOUTHEAST TO SOUTH MOTION ALONG THE SEA BREEZE.
THE MORNING ZONES UPDATE WILL TAKE A LOOK AT AMENDING WIND FIELDS AND
THE TIMING OF THE AFTERNOON STORMS.
&&
.AVIATION...PREVIOUS...PREVAILING VFR THROUGH 18Z WITH LCL MVFR CIGS
BKN025-030 DURING ONSET OF DIURNAL CU FIELD ~14Z-16Z. AFT
18Z...ISOLD SHRA/TS INCREASING IN COVERAGE 22Z-02Z. G30KT/1SM +TSRA
IN LOCALES WHERE CELL CORES MOVE OVHD...TYPICAL OF SUMMER CONVECTION.
&&
.MARINE...PREVIOUS...LIGHT S-SWRLY FLOW WILL GIVE WAY TO ONSHORE
ESE/SERLY SEA BREEZE AROUND 10KT NEAR THE COAST. SEAS 2-3FT...LCLY
HIGHER WINDS AND SEAS IN OFFSHORE MOVG TS MAINLY NORTH OF CAPE
CANAVERAL AND THE LATE AFTERNOON ON THE INLAND LAKES
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...WIMMER
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
336 PM EDT WED MAY 20 2015
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
MAIN FORECAST CONCERN IS WITH PRECIP POTENTIAL THIS EVENING INTO THE
EARLY MORNING AS A SHORTWAVE AND SOME ENHANCED MOISTURE APPROACHES
THE CWA FROM THE WEST. CURRENTLY A BAND OF SHOWERS AND STORMS IS
PUSHING INTO WESTERN ALABAMA AHEAD OF THIS DISTURBANCE WITH A WEAK
TRANSLATED SFC LOW. WHILE SOME HI-RES SOLUTIONS DO NOT APPEAR TO
SUPPORT THIS HOLDING TOGETHER AND PUSHING INTO WEST GA...SOME
PREVIOUS RAP SOLUTIONS SUPPORTED IT AND WILL NEED TO BE CLOSELY
MONITORED ESPECIALLY IF SOME OUTFLOW BOUNDARIES OR OTHER MESOSCALE
FORCING COMES TO AID. THIS MAY RESULT IN UPPING POPS IN WESTERN
PORTIONS OF THE AREA BY THIS EVENING. STILL SOME MLCAPE NEAR 1000
J/KG AND DECENT DCAPE IN PLACE. IF ANY STORM DEVELOPMENT CAN
MUSTER...THERE COULD STILL BE STRONG DOWNDRAFT WINDS EVEN THOUGH IT
IS A SHEAR DEPRIVED ENVIRONMENT. KEEPING BEST CHANCE POPS MAINLY
NORTH OF I-20 CORRIDOR INTO THE EARLY MORNING WITH THE SHORTWAVE
INFLUENCE.
PROGGED THERMAL PROFILES INDICATE GOOD DRYING OF THE COLUMN FOR
THURSDAY AND NOW BETTER AGREEMENT WITH A NOTABLE CAPPING INVERSION
ABOVE 850 MB. HAVE TRIMMED BACK POPS NOW TO ONLY HAVE A SLIGHT
CHANCE IN THE FAR SOUTHERN TIER FOR THE AFTERNOON...OTHERWISE
LOOKING TO STAY TOO DRY AND STABLE. WINDS LOOK TO BE KICKING IN WITH
THE STRENGTHENING PRESSURE GRADIENT AND AFTERNOON MIXING. WHILE
CURRENTLY LOOKING TO STAY A BIT BELOW CRITERIA...WILL NEED TO KEEP
AN EYE ON TRENDS FOR ANY FIRE DANGER CONCERNS WITH ALREADY DRY FUELS
/THOUGH MAY BE ALTERED WITH AFOREMENTIONED PRECIP CHANCES/. TEMPS
THURSDAY LOOK TO HAVE A STRONG GRADIENT WITH BELOW NORMAL HIGHS IN
THE MID/UPPER 70S FOR THE NW TO THE LOW 90S SE.
BAKER
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HAVE MADE A FEW MINOR ADJUSTMENTS TO POP AND WEATHER THROUGH THE
WEEKEND. LATEST LONG TERM MODELS HINT AT A MORE PROMINENT SURFACE
HIGH KEEPING MOISTURE TO THE WEST LARGELY AT BAY THROUGH
SUNDAY...WITH ONLY PORTIONS OF WESTERN AND NORTHERN GEORGIA AT
RISK FOR AN ISOLATED STORM. HAVE SCALED POPS BACK SOMEWHAT AS A
RESULT.
31
PREV DISCUSSION... /ISSUED 424 AM EDT WED MAY 20 2015/
LONG TERM PERIOD BEGINS A BIT DRIER AS THE FRONTAL SYSTEM WILL BE
SOUTH AND EAST OF THE AREA. HIGH PRESSURE BUILDING IN FROM THE
NORTHERN PLAINS AND MID WESTERN STATES BECOMES CENTERED OFF THE
MID ATLANTIC COAST AND STAYS THERE THROUGH THE WEEKEND. THIS RIDGE
CONTINUES TO ROTATE AND KEEPS THE DEEPER MOISTURE NORTH AND WEST
OF THE REGION THROUGH THE BEGINNING OF NEXT WEEK. THERE IS STILL
SOME MID AND UPPER LEVEL MOISTURE AROUND THE AREA SO WILL KEEP
SLIGHT CHANCE DIURNALLY DRIVEN POPS IN THE FORECAST DAYS 3-5. BY
TUESDAY THE RIDGE IS BEGINNING TO WEAKEN AND TRANSITION INTO MORE
OF A BERMUDA LIKE RIDGE. THIS WILL ALLOW DEEPER MOISTURE TO MOVE
IN FROM THE WEST ASSOCIATED WITH A WEAKENING FRONTAL BOUNDARY.
LOOKING AT INSTABILITIES INCREASING A BIT TUESDAY/WEDNESDAY ALONG
WITH PWS SO WILL INCREASE TO CHANCE POPS DAYS 6 AND 7.
01
&&
.AVIATION...
18Z UPDATE...
INITIAL VFR CONDITIONS WITH SCT-BKN CU FIELD IN 4-5 KFT AND SOME
VCSH IS POSSIBLE FOR MOST SITES FOR THE AFTERNOON. OTHERWISE
NEXT DISTURBANCE BRINGING SLIGHTLY BETTER CHANCE FOR -SHRA TONIGHT
IN 03-07Z PERIOD FOR KATL AND NEARBY NORTHERN SITES. ALSO CHANCE
FOR NORTHERN SITES TO GET MVFR CIGS IN 09-15Z THURSDAY MORNING.
WINDS MAINLY WNW 5-7 KTS INTO TONIGHT...THEN INCREASE TO 10-12 KTS
THURSDAY WITH GUSTS POSSIBLE 18-22 KTS.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON OVERNIGHT CIGS.
HIGH ON ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 66 85 56 81 / 20 10 10 5
ATLANTA 67 80 58 80 / 30 10 5 5
BLAIRSVILLE 61 74 48 74 / 30 20 10 5
CARTERSVILLE 64 79 53 79 / 30 10 5 5
COLUMBUS 70 88 61 84 / 10 10 10 5
GAINESVILLE 65 80 55 78 / 30 10 10 5
MACON 67 89 59 85 / 20 10 10 5
ROME 65 77 52 79 / 40 10 10 5
PEACHTREE CITY 65 83 54 81 / 20 10 5 5
VIDALIA 71 92 65 86 / 30 20 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....31
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1232 PM CDT Wed May 20 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 331 AM CDT WED MAY 20 2015
Mid/upper level trough currently lifting northeastward over SD and
NE, and will eventually merge with energy tracking over the upper
Midwest. An expansive area of light to moderate rain will move
across northeast KS early this morning, which is supported by upper
level forcing associated with the trough and low level
frontogenesis. Most of the forcing is forecast to continue eastward
and mainly exiting the area around 12Z. There are indications that
light rain showers and or drizzle could linger through the early
afternoon hours after the mid/upper levels dry out. Both RAP and NAM
soundings show steep low level lapse rates coinciding with
saturation along with weak lift. This could be enough to generate
these light showers and or drizzle. Although these models also
suggest isentropic downglide on the backside of the wave so very
little precip accumulations are expected after 12Z. Clouds will
stick around most of the day and northerly flow will keep
temperatures from warming up much, therefore highs will generally be
in the mid 50s. Surface high pressure will build into the region
tonight and clouds may begin to scatter out as the drier air filters
southward. As surface winds begin to lighten and temperatures cool
there is a chance fog could develop especially given the recent
rainfall. Temperatures are expected to drop into the low to mid 40s
with a few isolated locations in the upper 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 AM CDT WED MAY 20 2015
Thursday through Thursday night, A surface ridge of high pressure
over eastern KS will shift east into MO by Friday morning. An upper
level trough will move onshore across southern CA. Expect mostly
sunny skies on Thursday with highs reaching the mid 60s. Thursday
night will be a bit warmer as the center of the surface ridge moves
east into MO, allowing light winds to become southerly. Lows Friday
morning will only drop into the mid to upper 40s. High and mid level
clouds will increase late Thursday night.
Friday through Monday, The upper trough over southern CA will slowly
drift northeast into western CO and slowly fill. Southwest flow
aloft across the central Rockies will cause a surface lee trough to
deepen across the central and southern high plains. Deeper gulf
moisture will gradually be advected northward into the southern
plains Friday afternoon. The resulting isentropic lift ahead of the
deeper moisture return combined with any ascent from minor H5
troughs embedded within the southern stream of the H5 jet will
provide an increasing chance for showers and isolated thunderstorms
during the day Friday and into the Friday evening. The ECMWF shows a
brief amplification of the main H5 trough across AZ. This may
amplify a downstream H5 ridge across the southern plains which may
provide a break from the showers and thunderstorms across eastern KS
on Saturday. Due to cloud cover and increasing rain chances on
Friday, highs will only reach the mid 60s. If we see more insolation
on Saturday highs will reach the lower 70s.
Saturday night through Sunday night, the Upper trough will fill as
it lifts northeast into western CO. The southern stream H5 ridge
will shift east across the Gulf coast states. Embedded shortwave
trough combined with deeper moisture advection will cause periods of
showers and thunderstorms to develop. The mid level flow will weaken
below 40 KTS. The weaker vertical wind shear should prevent
organized storms updrafts. Also, the instability may be lower due to
the cloud cover. I don`t expect severe thunderstorms this weekend.
The primary hazard may be occasional heavy rainfall. Highs on Sunday
will reach the mid 70s
Monday (Memorial Day), The ECMWF and GEM forecast a slightly more
amplified H5 trough to move northeast from southwest TX into central
OK. The better ascent ahead of this trough will be across northern
TX and southern OK. Both models do not forecast much in the way of
QPF during the day. The showers and thunderstorms may increase
Monday night as the H5 trough lifts northeast into western MO. Highs
on Monday should reach the mid 70s
Tuesday, the H5 trough across western MO will lift northeast into
eastern IA and IL. We may see a break in the precip. The GFS is
slower moving the H5 trough northeast across MO and forecast higher
QPF across eastern KS on Tuesday. Looks a bit warmer on Tuesday as
16 to 18 degree C 850mb temps advect northeast across the CWA. Highs
should reach into the upper 70s to around 80.
&&
.AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon)
Issued at 1232 PM CDT WED MAY 20 2015
Expect slight improvements to rather frequent IFR cigs in next few
hours given typical diurnal trends and upstream obs, though
confidence is not high. Timing of stratus exit also difficult, but
guidance similar with a delayed exit from earlier expectations. Am
not too worried about FG development around 11Z at this point
with some boundary layer mixing occuring.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
625 AM CDT Wed May 20 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 331 AM CDT WED MAY 20 2015
Mid/upper level trough currently lifting northeastward over SD and
NE, and will eventually merge with energy tracking over the upper
Midwest. An expansive area of light to moderate rain will move
across northeast KS early this morning, which is supported by upper
level forcing associated with the trough and low level
frontogenesis. Most of the forcing is forecast to continue eastward
and mainly exiting the area around 12Z. There are indications that
light rain showers and or drizzle could linger through the early
afternoon hours after the mid/upper levels dry out. Both RAP and NAM
soundings show steep low level lapse rates coinciding with
saturation along with weak lift. This could be enough to generate
these light showers and or drizzle. Although these models also
suggest isentropic downglide on the backside of the wave so very
little precip accumulations are expected after 12Z. Clouds will
stick around most of the day and northerly flow will keep
temperatures from warming up much, therefore highs will generally be
in the mid 50s. Surface high pressure will build into the region
tonight and clouds may begin to scatter out as the drier air filters
southward. As surface winds begin to lighten and temperatures cool
there is a chance fog could develop especially given the recent
rainfall. Temperatures are expected to drop into the low to mid 40s
with a few isolated locations in the upper 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 AM CDT WED MAY 20 2015
Thursday through Thursday night, A surface ridge of high pressure
over eastern KS will shift east into MO by Friday morning. An upper
level trough will move onshore across southern CA. Expect mostly
sunny skies on Thursday with highs reaching the mid 60s. Thursday
night will be a bit warmer as the center of the surface ridge moves
east into MO, allowing light winds to become southerly. Lows Friday
morning will only drop into the mid to upper 40s. High and mid level
clouds will increase late Thursday night.
Friday through Monday, The upper trough over southern CA will slowly
drift northeast into western CO and slowly fill. Southwest flow
aloft across the central Rockies will cause a surface lee trough to
deepen across the central and southern high plains. Deeper gulf
moisture will gradually be advected northward into the southern
plains Friday afternoon. The resulting isentropic lift ahead of the
deeper moisture return combined with any ascent from minor H5
troughs embedded within the southern stream of the H5 jet will
provide an increasing chance for showers and isolated thunderstorms
during the day Friday and into the Friday evening. The ECMWF shows a
brief amplification of the main H5 trough across AZ. This may
amplify a downstream H5 ridge across the southern plains which may
provide a break from the showers and thunderstorms across eastern KS
on Saturday. Due to cloud cover and increasing rain chances on
Friday, highs will only reach the mid 60s. If we see more insolation
on Saturday highs will reach the lower 70s.
Saturday night through Sunday night, the Upper trough will fill as
it lifts northeast into western CO. The southern stream H5 ridge
will shift east across the Gulf coast states. Embedded shortwave
trough combined with deeper moisture advection will cause periods of
showers and thunderstorms to develop. The mid level flow will weaken
below 40 KTS. The weaker vertical wind shear should prevent
organized storms updrafts. Also, the instability may be lower due to
the cloud cover. I don`t expect severe thunderstorms this weekend.
The primary hazard may be occasional heavy rainfall. Highs on Sunday
will reach the mid 70s
Monday (Memorial Day), The ECMWF and GEM forecast a slightly more
amplified H5 trough to move northeast from southwest TX into central
OK. The better ascent ahead of this trough will be across northern
TX and southern OK. Both models do not forecast much in the way of
QPF during the day. The showers and thunderstorms may increase
Monday night as the H5 trough lifts northeast into western MO. Highs
on Monday should reach the mid 70s
Tuesday, the H5 trough across western MO will lift northeast into
eastern IA and IL. We may see a break in the precip. The GFS is
slower moving the H5 trough northeast across MO and forecast higher
QPF across eastern KS on Tuesday. Looks a bit warmer on Tuesday as
16 to 18 degree C 850mb temps advect northeast across the CWA. Highs
should reach into the upper 70s to around 80.
&&
.AVIATION...(For the 12Z TAFs through 12Z Thursday Morning)
Issued at 619 AM CDT WED MAY 20 2015
MVFR/IFR conditions look to persist through a majority of the taf
period. Most of the rain has ended although an isolated shower can
not be ruled out through early afternoon. These showers should
not really affect the flight conditions. Model forecasts have
ceilings around 1 kft making it difficult to predict the category.
There are signs the clouds try to scatter out tonight and fog
could also be an issue late in the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS TOPEKA KS
332 AM CDT Wed May 20 2015
.SHORT TERM...(Today and Tonight)
Issued at 331 AM CDT WED MAY 20 2015
Mid/upper level trough currently lifting northeastward over SD and
NE, and will eventually merge with energy tracking over the upper
Midwest. An expansive area of light to moderate rain will move
across northeast KS early this morning, which is supported by upper
level forcing associated with the trough and low level
frontogenesis. Most of the forcing is forecast to continue eastward
and mainly exiting the area around 12Z. There are indications that
light rain showers and or drizzle could linger through the early
afternoon hours after the mid/upper levels dry out. Both RAP and NAM
soundings show steep low level lapse rates coinciding with
saturation along with weak lift. This could be enough to generate
these light showers and or drizzle. Although these models also
suggest isentropic downglide on the backside of the wave so very
little precip accumulations are expected after 12Z. Clouds will
stick around most of the day and northerly flow will keep
temperatures from warming up much, therefore highs will generally be
in the mid 50s. Surface high pressure will build into the region
tonight and clouds may begin to scatter out as the drier air filters
southward. As surface winds begin to lighten and temperatures cool
there is a chance fog could develop especially given the recent
rainfall. Temperatures are expected to drop into the low to mid 40s
with a few isolated locations in the upper 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 AM CDT WED MAY 20 2015
Thursday through Thursday night, A surface ridge of high pressure
over eastern KS will shift east into MO by Friday morning. An upper
level trough will move onshore across southern CA. Expect mostly
sunny skies on Thursday with highs reaching the mid 60s. Thursday
night will be a bit warmer as the center of the surface ridge moves
east into MO, allowing light winds to become southerly. Lows Friday
morning will only drop into the mid to upper 40s. High and mid level
clouds will increase late Thursday night.
Friday through Monday, The upper trough over southern CA will slowly
drift northeast into western CO and slowly fill. Southwest flow
aloft across the central Rockies will cause a surface lee trough to
deepen across the central and southern high plains. Deeper gulf
moisture will gradually be advected northward into the southern
plains Friday afternoon. The resulting isentropic lift ahead of the
deeper moisture return combined with any ascent from minor H5
troughs embedded within the southern stream of the H5 jet will
provide an increasing chance for showers and isolated thunderstorms
during the day Friday and into the Friday evening. The ECMWF shows a
brief amplification of the main H5 trough across AZ. This may
amplify a downstream H5 ridge across the southern plains which may
provide a break from the showers and thunderstorms across eastern KS
on Saturday. Due to cloud cover and increasing rain chances on
Friday, highs will only reach the mid 60s. If we see more insolation
on Saturday highs will reach the lower 70s.
Saturday night through Sunday night, the Upper trough will fill as
it lifts northeast into western CO. The southern stream H5 ridge
will shift east across the Gulf coast states. Embedded shortwave
trough combined with deeper moisture advection will cause periods of
showers and thunderstorms to develop. The mid level flow will weaken
below 40 KTS. The weaker vertical wind shear should prevent
organized storms updrafts. Also, the instability may be lower due to
the cloud cover. I don`t expect severe thunderstorms this weekend.
The primary hazard may be occasional heavy rainfall. Highs on Sunday
will reach the mid 70s
Monday (Memorial Day), The ECMWF and GEM forecast a slightly more
amplified H5 trough to move northeast from southwest TX into central
OK. The better ascent ahead of this trough will be across northern
TX and southern OK. Both models do not forecast much in the way of
QPF during the day. The showers and thunderstorms may increase
Monday night as the H5 trough lifts northeast into western MO. Highs
on Monday should reach the mid 70s
Tuesday, the H5 trough across western MO will lift northeast into
eastern IA and IL. We may see a break in the precip. The GFS is
slower moving the H5 trough northeast across MO and forecast higher
QPF across eastern KS on Tuesday. Looks a bit warmer on Tuesday as
16 to 18 degree C 850mb temps advect northeast across the CWA. Highs
should reach into the upper 70s to around 80.
&&
.AVIATION...(For the 06Z TAFs through 06Z Wednesday Night)
Issued at 1127 PM CDT TUE MAY 19 2015
Drier air behind the departing wave has allowed the lower categories
to remain west of terminals thus far. Short term guidance is still
trending with the showers west of KMHK to track east through 11Z.
Confidence is decent in MVFR ceilings, however IFR is a bit more
uncertain at KTOP/KFOE, with the better chances for a heavier
shower and therefore the lower ceilings to impact KMHK. Ceilings
gradually recover back to high end MVFR by the afternoon as
northerly winds hover near 10 kts throughout the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS PADUCAH KY
635 AM CDT WED MAY 20 2015
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 316 AM CDT WED MAY 20 2015
TIGHTER ZONAL GRADIENT DEVELOPS TODAY IN THE WAKE OF THE DEPARTING
AND DAMPENING LOW/MIDDLE LEVEL RIDGE. COMBINED WITH SLIGHTLY
STRONGER VORTICITY IN MINOR LOW AMPLITUDE NORTH-SOUTH SHORTWAVE
SHOULD PROVIDE SUFFICIENT LIFT FOR SHOWER ACTIVITY. STILL BELIEVE
THE ANTECEDENT CLOUD COVER AND COOLER BOUNDARY LAYER TEMPERATURES
IN NORTHERLY/NORTHEASTERLY WOULD PROVIDE SUFFICIENT LIFT FOR
SHOWER GENERATION. OVERALL INSTABILITY ALOFT WILL BE ENOUGH TO
SUPPORTED LIMITED THUNDERSTORM CHANCES ALONG THE SOUTHERN 1/3 OF
THE WFO PAH FORECAST AREA.
THE EXTENT OF CLOUD COVER AND NORTH/NORTHEASTERLY COOL/DRY FLOW
FROM THE DEPARTING RIDGE WILL DETERMINE THE EASTWARD MOVEMENT OF
THE PRECIPITATION TODAY AND THIS EVENING ACROSS THE WFO PAH
FORECAST AREA. THE HRRR AND GFS GUIDANCE SUPPORT A MORE
PROGRESSIVE AND FASTER SCENARIO, BUT WITH LESSER RESIDENCE TIME
FOR INSTABILITY ACROSS THE AREA. BLENDED THIS GUIDANCE WITH
EXISTING FORECAST.
BEYOND TONIGHT...DRY CONDITIONS SHOULD RETURN TO THE FORECAST AREA
THROUGH NEARLY ALL OF FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 316 AM CDT WED MAY 20 2015
ABOVE AVERAGE FORECAST CONFIDENCE IN THE LONG TERM WITH MODELS
SHOWING MINOR DISAGREEMENTS.
AT THE BEGINNING OF THE LONG TERM PERIOD...AN H5 RIDGE IN PLACE OVER
THE REGION BEGINS TO FLATTEN AND SHIFT EASTWARD ALLOWING DEEPER
MOISTURE AND A SERIES OF UPPER LEVEL DISTURBANCES TO SPREAD
PRECIPITATION CHANCES EASTWARD ACROSS THE REGION. AS THE RIDGE AXIS
SHIFTS FARTHER EASTWARD...PRECIPITATION CHANCES WILL GENERALLY
INCREASE THROUGH THE LONG TERM PERIOD.
TEMPERATURES SHOULD REMAIN AT OR ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
ISSUED AT 635 AM CDT WED MAY 20 2015
ONLY A SLIGHT CHANGE FROM THE 06Z WEDNESDAY WFO PAH TAF ISSUANCE.
THE MAIN ADJUSTMENT WAS TO RAISE CEILINGS/CLOUD DECKS BY 1-2KFT AT
THE ONSET OF CLOUD COVER AND RAISE LATTER PERIOD CEILINGS FROM
UPPER IFR TO LOWER MVFR, ESPECIALLY DURING THE LAST 10-13 HOURS OF
THE FORECAST PERIOD.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...JP
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS PADUCAH KY
318 AM CDT WED MAY 20 2015
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 316 AM CDT WED MAY 20 2015
TIGHTER ZONAL GRADIENT DEVELOPS TODAY IN THE WAKE OF THE DEPARTING
AND DAMPENING LOW/MIDDLE LEVEL RIDGE. COMBINED WITH SLIGHTLY
STRONGER VORTICITY IN MINOR LOW AMPLITUDE NORTH-SOUTH SHORTWAVE
SHOULD PROVIDE SUFFICIENT LIFT FOR SHOWER ACTIVITY. STILL BELIEVE
THE ANTECEDENT CLOUD COVER AND COOLER BOUNDARY LAYER TEMPERATURES
IN NORTHERLY/NORTHEASTERLY WOULD PROVIDE SUFFICIENT LIFT FOR
SHOWER GENERATION. OVERALL INSTABILITY ALOFT WILL BE ENOUGH TO
SUPPORTED LIMITED THUNDERSTORM CHANCES ALONG THE SOUTHERN 1/3 OF
THE WFO PAH FORECAST AREA.
THE EXTENT OF CLOUD COVER AND NORTH/NORTHEASTERLY COOL/DRY FLOW
FROM THE DEPARTING RIDGE WILL DETERMINE THE EASTWARD MOVEMENT OF
THE PRECIPITATION TODAY AND THIS EVENING ACROSS THE WFO PAH
FORECAST AREA. THE HRRR AND GFS GUIDANCE SUPPORT A MORE
PROGRESSIVE AND FASTER SCENARIO, BUT WITH LESSER RESIDENCE TIME
FOR INSTABILITY ACROSS THE AREA. BLENDED THIS GUIDANCE WITH
EXISTING FORECAST.
BEYOND TONIGHT...DRY CONDITIONS SHOULD RETURN TO THE FORECAST AREA
THROUGH NEARLY ALL OF FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 316 AM CDT WED MAY 20 2015
ABOVE AVERAGE FORECAST CONFIDENCE IN THE LONG TERM WITH MODELS
SHOWING MINOR DISAGREEMENTS.
AT THE BEGINNING OF THE LONG TERM PERIOD...AN H5 RIDGE IN PLACE OVER
THE REGION BEGINS TO FLATTEN AND SHIFT EASTWARD ALLOWING DEEPER
MOISTURE AND A SERIES OF UPPER LEVEL DISTURBANCES TO SPREAD
PRECIPITATION CHANCES EASTWARD ACROSS THE REGION. AS THE RIDGE AXIS
SHIFTS FARTHER EASTWARD...PRECIPITATION CHANCES WILL GENERALLY
INCREASE THROUGH THE LONG TERM PERIOD.
TEMPERATURES SHOULD REMAIN AT OR ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
ISSUED AT 1157 PM CDT TUE MAY 19 2015
NORTH/NORTHEAST WINDS AND VFR CONDITIONS INTO WEDNESDAY MORNING. A
WEAKENING SURFACE LOW/TROUGH WILL PASS EAST TO THE SOUTH OF THE
AREA THROUGH THE AFTERNOON AND EVENING HOURS. SHRA/RA WILL BE
ACCOMPANY IT THROUGH THE REGION. NOT SURE HOW FAST SATURATION WILL
OCCUR...BUT IT SHOULD BE QUICKER AND RESULT IN LOWER CONDITIONS AT KCGI
AND KPAH THAN AT KEVV AND KOWB. THE WORST CONDITIONS IN BR/DZ WILL
BE BEHIND THE MORE SIGNIFICANT RAINS INTO THE EVENING. WENT AS
LOW AS IFR CONDITIONS IN THE EVENING IN THE SOUTHWEST...BUT KEPT
IT AT MVFR IN THE NORTHEAST. TRIED TO STAY ON THE OPTIMISTIC SIDE
OF GUIDANCE...SO LOWER CONDITIONS CANNOT BE RULED OUT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...JP
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
942 PM CDT THU MAY 21 2015
.DISCUSSION...
PRECIPITATION FOR THE MOST PART HAS ENDED ACROSS THE FOUR STATE
REGION LATE THIS EVENING. SOME REDUCTIONS IN VISIBILITY ACROSS NE
TX FROM THE I-20 CORRIDOR SOUTHWARD SUGGESTS THAT THERE MAY STILL
BE SOME PATCHY DRIZZLE ACROSS THESE LOCATIONS ATTM. FOR THE
EVENING UPDATE...HAVE KEPT SLIGHT CHANCE POPS GOING BASICALLY
ALONG AND SOUTH OF A LINE FROM TYR/GGG TO THE LOWER TOLEDO BEND
RESERVOIR. LATEST 00Z WRF OUTPUT DOES NOT GENERATE ANY PRECIP
ACROSS THIS REGION BUT THIS WILL BE A FAVORABLE REGION FOR WEAK
ISENTROPIC LIFT AS SOUTHERLY WINDS DO RETURN AT THE 8H LEVEL WHICH
WILL OVERRUN A NE WIND IN THE LOWER LEVELS. THE LATEST HRRR OUTPUT
DOES SUGGEST SOME WEAK REDEVELOPMENT ACROSS OUR SOUTHWEST ZONES
AFTER MIDNIGHT.
CONCERNING TEMPERATURES...DID LOWER OVERNIGHT MIN TEMPS A DEGREE
OR TWO...MAINLY ALONG AND SOUTH OF THE I-20 CORRIDOR OF NE TX/N LA
WHERE 02Z TEMPS WERE ONLY A DEGREE OR SO FROM FCST MINS. CLOUD
COVER HAS SCOWERED OUT ACROSS OUR EXTREME NW ZONES BUT SHOULD FILL
IN OVERNIGHT WITH 7H MOISTURE.
OTHER CHANGES INCLUDED DEWPOINT/RH AND WIND GRIDS TO MIMIC CURRENT
AND EXPECTED CHANGES OVERNIGHT...OTHERWISE THE FORECAST IS IN
PRETTY GOOD SHAPE.
NO OTHER SIGNIFICANT CHANGES ATTM. PRELIMS ARE AS FOLLOWS...13.
&&
.PREV DISCUSSION... /ISSUED 652 PM CDT THU MAY 21 2015/
AVIATION...
LOW CIGS WILL CONTINUE TO AFFECT THE TERMINALS FOR MUCH OF THE TAF
PD...WITH THE EXCEPTION OF KTXK...WHICH SHOULD RETURN TO VFR
WITHIN THE NEXT FEW HOURS. EXPECT NE TO ESELY WINDS AT 5-10 KTS
THROUGHOUT THE PD. /12/
PREV DISCUSSION... /ISSUED 350 PM CDT THU MAY 21 2015/
DISCUSSION...
WATER VAPOR IMAGERY CONTINUES TO SHOW A DISTURBANCE MOVING EAST
THIS AFTERNOON...OUT OF THE ARKLATEX REGION. HOWEVER...SCATTERED
SHOWERS CONTINUE ACROSS THE REGION...WITH THE BRUNT OF THE
SHOWERS EXTENDING FROM LUFKIN EAST TO LOUISIANA. THIS SHOWERS
ACTIVITY WILL GRADUALLY SHIFT SOUTH AND EAST THROUGH THE
EVENING..WITH JUST A FEW ISOLATED SHOWERS CONTINUING INTO THE
OVERNIGHT HOURS.
A TRANSITORY WEAK RIDGE WILL BUILD BACK ACROSS THE ARKLATEX FOR
FRIDAY. AT THIS POINT IN TIME...THINK THAT MOST OF THE REGION WILL
PROBABLY BE DRY...BUT HAVE LEFT IN A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS...MAINLY FOR WESTERN AREAS...AS SOME MOISTURE DOES
TRY TO SPREAD INTO THE AREA FROM TEXAS. THIS RIDGE WILL SHIFT EAST
ON SATURDAY...OPENING THE DOOR FOR A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THE WEEKEND.
THE PERIODS OF MOST CONCERN IN THE FORECAST ARE REALLY SUNDAY AND
MONDAY...AS THE NEXT WEST COAST LOW MOVES INTO THE CENTRAL PART OF
THE US BEFORE PUSHING EAST. SHOWERS AND THUNDERSTORMS WILL LIKELY
DEVELOP ACROSS THE REGION ON SUNDAY...WITH A DISTURBANCE AHEAD OF
THE MAIN TROUGH AIDS IN THE LIFT. THE MAIN TROUGH THEN SHIFTS EAST
ACROSS THE REGION LATE SUNDAY AND INTO MONDAY. PRECIPITABLE WATER
VALUES WILL INCREASE TO BETWEEN 1.6 AND 2.1 INCHES DURING THIS
TIME...MEANING THAT ANY THUNDERSTORMS THAT DEVELOP WILL BE VERY
EFFICIENT RAIN PRODUCERS...WITH PERIODS OF HEAVY RAIN LIKELY.
GIVEN HOW SATURATED THE GROUND IS WITH THE RECENT RAINS...BELIEVE
FLASH FLOODING WILL ALSO BE LIKELY THESE DAYS. HAVE HELD OFF
ISSUING A FLASH FLOOD WATCH FOR SUNDAY AND MONDAY AT THIS
TIME...JUST TO GIVE THE MODELS ANOTHER DAY TO FINE TUNE THE
TIMING...BUT BELIEVE ONE WILL BE NEEDED FOR THESE DAYS.
THE EXTENDED MODELS START TO VARY ON THE TIMING FOR TUESDAY
THROUGH THURSDAY...BUT FOR NOW IT APPEARS THAT THE REGION WILL
EITHER BE UNDER SOUTHWESTERLY FLOW ALOFT OR ANOTHER TROUGH.
THEREFORE...EXPECT THE THREAT OF UNSETTLED WEATHER TO CONTINUE
THROUGH AT LEAST THURSDAY.
HYDROLOGY...
THE POTENTIAL FOR A MAJOR FLOOD TO DEVELOP ALONG THE RED RIVER
CONTINUES TO BE A CONCERN. THE WEATHER PREDICTION CENTER IS
FORECASTING UPWARDS OF 8 INCHES OF PRECIPITATION FALLING OVER THE
RED RIVER BASIN UPSTREAM OF LAKE TEXOMA IN THE NEXT 7 DAYS. THIS
ADDITIONAL RAINFALL ON ALREADY SATURATED GROUND WILL INCREASE
THE LIKELIHOOD OF A MAJOR FLOOD EVENT ALONG THE RED RIVER...THE
FIRST TIME SINCE 1990. OUR MODELS ARE ALSO HINTING THAT A
SIGNIFICANT AMOUNT OF PRECIPITATION MAY FALL ALONG THE RED RIVER
AS THE CREST MOVES SOUTH TOWARDS SHREVEPORT. THIS ADDS AN
ADDITIONAL LEVEL OF CONCERN. NEEDLESS TO SAY...WE WILL CONTINUE
TO MONITOR THIS DEVELOPING SITUATION. FOR MORE INFORMATION ON THE
RED RIVER STAGES AND FORECASTS...PLEASE SEE NEWPNSSHV OR NOUS44
KSHV OR THE CURRENT AND FORECASTED RIVER LEVELS LINK ON OUR
WEBSITE AT WEATHER.GOV/SHV.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 59 77 65 83 / 10 20 20 50
MLU 56 76 63 84 / 10 20 20 50
DEQ 55 72 60 79 / 10 40 20 50
TXK 56 73 61 81 / 10 30 20 50
ELD 54 74 61 82 / 10 20 20 50
TYR 60 76 66 82 / 20 40 20 40
GGG 59 77 66 83 / 20 30 20 40
LFK 64 80 69 84 / 20 40 20 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
03/12/13
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
915 PM EDT THU MAY 21 2015
LATEST UPDATE...
MARINE
.SYNOPSIS...
ISSUED AT 329 PM EDT THU MAY 21 2015
SCATTERED RAIN SHOWERS WILL MOVE SOUTH THROUGH THE AREA WITH A COLD
FRONT. BEHIND THIS FRONT...HIGH TEMPERATURES FRIDAY WILL BE AROUND
60...WHICH IS ABOUT 10 DEGREES BELOW NORMAL THIS TIME OF YEAR.
PATCHY FROST IS POSSIBLE OVER PARTS OF CENTRAL LOWER MICHIGAN FRIDAY
MORNING. THERE IS EVEN BETTER POTENTIAL FOR FROST SATURDAY MORNING.
RAIN CHANCES RETURN SUNDAY AFTERNOON WITH A WARMER AND WETTER
PATTERN LASTING WELL INTO NEXT WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 329 PM EDT THU MAY 21 2015
SCATTERED SHOWERS ARE POSSIBLE THIS EVENING. COOLER THAN NORMAL
TEMPERATURES WILL PERSIST THROUGH FRIDAY NIGHT. FROST FORMATION IS
POSSIBLE TONIGHT MAINLY ACROSS CENTRAL LOWER MICHIGAN. WIDESPREAD
AREAS OF FROST ARE MORE LIKELY LATE FRIDAY NIGHT INTO SATURDAY
MORNING.
A WEAK COLD FRONT WILL DROP SOUTH THROUGH LOWER MICHIGAN THIS
EVENING AS AN UPPER LEVEL SHORTWAVE PROPAGATES OVER THE LOWER GREAT
LAKES REGION. MOISTURE IS CONFINED TO THE MID LEVELS WITH CLOUD
BASES AROUND 9K FEET. SFC DEWPOINTS ARE ONLY IN THE 30S TO LOWER
40S. ALL THIS SHOULD RESULT IN ISOLATED TO SCATTERED LIGHT RAIN
SHOWERS...CONFIRMED BY THE LAST SEVERAL RUNS OF THE RAP AND HRRR. A
SIMILAR AIRMASS YESTERDAY EVENING RESULTED IN A RAIN/SLEET MIX
MAINLY IN THE CHICAGO AREA. BUT PRECIP THIS EVENING WILL LIKELY NOT
BE HEAVY ENOUGH TO CAUSE SIGNIFICANT WET-BULBING.
MID-LEVEL CLOUDS WILL START TO CLEAR OUT FROM NORTH TO SOUTH LATE
TONIGHT AND WINDS WILL SUBSIDE AS THEY VEER NORTHERLY BEHIND THE SFC
FRONT. THIS SHOULD ALLOW DECENT RADIATIONAL COOLING CONDITIONS TO
SET UP AFTER MIDNIGHT. FROST WILL BE POSSIBLE ACROSS CENTRAL LOWER
MICHIGAN.
ANOTHER COOL DAY IS EXPECTED ON FRIDAY WITH NORTHWEST FLOW AT THE
SURFACE. BUT PLENTY OF SUNSHINE IS EXPECTED AS A SURFACE HIGH BUILDS
IN. UPPER RIDGING WILL CONTINUE TO BUILD IN THROUGH SATURDAY NIGHT
AS THE SFC HIGH SLIDES OFF TO THE SOUTHEAST. FAIR WEATHER IS
EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT...BUT THIS SHOULD ALLOW
GOOD FROST CONDITIONS TO SET UP FRIDAY NIGHT INTO SATURDAY MORNING.
WITH CLEAR SKIES AND LIGHT WINDS...LOWS WILL LIKELY DROP INTO THE
LOW TO MID 30S ACROSS MUCH OF THE FORECAST AREA. SOUTHWEST RETURN
FLOW FINALLY SETS UP SATURDAY...ALONG WITH PLENTY OF SUNSHINE AND
HIGHS IN THE LOWER 70S.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 329 PM EDT THU MAY 21 2015
THE MAIN STORY IN THE LONG TERM PERIOD IS THAT WE WILL FINALLY SEE
WARMER TEMPERATURES AS THE PERSISTENT HUDSON BAY UPPER LOW RETREATS
AND WE GET INTO DEEP SOUTHWEST FLOW. HIGHS IN THE 70S ARE LIKELY
AWAY FROM LK MI... WITH PERHAPS 80 DEGREES AND NOTICEABLY MORE HUMID
FROM MONDAY ON.
PROLONGED WARM ADVECTION PATTERN WITH A FLOW OFF THE GULF AND A
QUASI STATIONARY FRONTAL BOUNDARY WILL LIKELY LEAD TO ROUNDS OF
SHOWERS AND POSSIBLE TSTMS. HOWEVER THE TIMING/LOCATION/DURATION OF
CONVECTIVE EPISODES AND DAILY POSITION OF THE SFC FRONT IS LOW
CONFIDENCE AT THIS TIME. CURRENTLY WE HAVE THE HIGHEST POPS ON
SUNDAY NIGHT AND MONDAY WHICH IS WHEN THE SFC WARM FRONT IS LIFTING
NORTH THROUGH THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 726 PM EDT THU MAY 21 2015
BAND OF SHOWERS WILL DROP SOUTHEAST THROUGH THE TAF SITES THIS
EVENING RESULTING IN A WIND SHIFT. VFR WEATHER IS FORECASTED TO
PREVAIL...AND A FEW GUSTS OVER 20 KNOTS COULD ACCOMPANY THE
PASSAGE OF THESE SHOWERS. HIGH PRESSURE MOVES IN FOR FRIDAY AND
THAT WILL HELP TO KEEP CONDITIONS VFR.
&&
.MARINE...
ISSUED AT 913 PM EDT THU MAY 21 2015
WAVES WERE SLIGHTLY HIGHER THAN FORECASTED...MAINLY DUE TO THE
STRONGER FLOW OUT AHEAD OF THE COLD FRONT. THE UPDATED FORECAST
REFLECTS THESE HIGHER VALUES. NO HEADLINE AS THE VALUES WERE BELOW
CRITERIA PLUS WITH THE FRONT TO PUSH SOUTH IN THE NEXT FEW
HOURS...THE WIND VALUES DROP OFF BEHIND IT.
&&
.HYDROLOGY...
ISSUED AT 1240 PM EDT THU MAY 21 2015
NO CONCERNS THROUGH THE WEEKEND. PRECIPITATION THAT COULD AFFECT
MAINSTEM RIVERS IS NOT EXPECTED UNTIL LATE SUNDAY...WHICH MARKS THE
START OF A WETTER PATTERN LASTING WELL INTO THE COMING WORK WEEK.
NATIONAL GUIDANCE ADVERTISES UNIFORM RAINFALL TOTALS OF 1-1.5
INCHES ACROSS THE AREA THROUGH THURSDAY MORNING. GIVEN THAT BASE
FLOWS ARE NEAR OR BELOW NORMAL AND THAT RAIN SHOULD BE SPREAD OUT
OVER TIME...WE EXPECT FAIRLY GENTLE RISES WILL BE UNDERWAY BY THE
MIDDLE OF NEXT WEEK.
THAT SAID...FORECASTING CONVECTIVE RAINFALL THIS FAR OUT IS
HIGHLY UNCERTAIN SO THERE STILL REMAINS A FAIRLY WIDE RANGE OF
POSSIBILITIES FOR RAINFALL AND RIVER RESPONSES AT THIS POINT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 3 AM TO 9 AM EDT FRIDAY FOR MIZ037>040-
043>046.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...EBW
LONG TERM...MEADE
AVIATION...MJS
HYDROLOGY...TJT
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
728 PM EDT THU MAY 21 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 329 PM EDT THU MAY 21 2015
SCATTERED RAIN SHOWERS WILL MOVE SOUTH THROUGH THE AREA WITH A COLD
FRONT. BEHIND THIS FRONT...HIGH TEMPERATURES FRIDAY WILL BE AROUND
60...WHICH IS ABOUT 10 DEGREES BELOW NORMAL THIS TIME OF YEAR.
PATCHY FROST IS POSSIBLE OVER PARTS OF CENTRAL LOWER MICHIGAN FRIDAY
MORNING. THERE IS EVEN BETTER POTENTIAL FOR FROST SATURDAY MORNING.
RAIN CHANCES RETURN SUNDAY AFTERNOON WITH A WARMER AND WETTER
PATTERN LASTING WELL INTO NEXT WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 329 PM EDT THU MAY 21 2015
SCATTERED SHOWERS ARE POSSIBLE THIS EVENING. COOLER THAN NORMAL
TEMPERATURES WILL PERSIST THROUGH FRIDAY NIGHT. FROST FORMATION IS
POSSIBLE TONIGHT MAINLY ACROSS CENTRAL LOWER MICHIGAN. WIDESPREAD
AREAS OF FROST ARE MORE LIKELY LATE FRIDAY NIGHT INTO SATURDAY
MORNING.
A WEAK COLD FRONT WILL DROP SOUTH THROUGH LOWER MICHIGAN THIS
EVENING AS AN UPPER LEVEL SHORTWAVE PROPAGATES OVER THE LOWER GREAT
LAKES REGION. MOISTURE IS CONFINED TO THE MID LEVELS WITH CLOUD
BASES AROUND 9K FEET. SFC DEWPOINTS ARE ONLY IN THE 30S TO LOWER
40S. ALL THIS SHOULD RESULT IN ISOLATED TO SCATTERED LIGHT RAIN
SHOWERS...CONFIRMED BY THE LAST SEVERAL RUNS OF THE RAP AND HRRR. A
SIMILAR AIRMASS YESTERDAY EVENING RESULTED IN A RAIN/SLEET MIX
MAINLY IN THE CHICAGO AREA. BUT PRECIP THIS EVENING WILL LIKELY NOT
BE HEAVY ENOUGH TO CAUSE SIGNIFICANT WET-BULBING.
MID-LEVEL CLOUDS WILL START TO CLEAR OUT FROM NORTH TO SOUTH LATE
TONIGHT AND WINDS WILL SUBSIDE AS THEY VEER NORTHERLY BEHIND THE SFC
FRONT. THIS SHOULD ALLOW DECENT RADIATIONAL COOLING CONDITIONS TO
SET UP AFTER MIDNIGHT. FROST WILL BE POSSIBLE ACROSS CENTRAL LOWER
MICHIGAN.
ANOTHER COOL DAY IS EXPECTED ON FRIDAY WITH NORTHWEST FLOW AT THE
SURFACE. BUT PLENTY OF SUNSHINE IS EXPECTED AS A SURFACE HIGH BUILDS
IN. UPPER RIDGING WILL CONTINUE TO BUILD IN THROUGH SATURDAY NIGHT
AS THE SFC HIGH SLIDES OFF TO THE SOUTHEAST. FAIR WEATHER IS
EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT...BUT THIS SHOULD ALLOW
GOOD FROST CONDITIONS TO SET UP FRIDAY NIGHT INTO SATURDAY MORNING.
WITH CLEAR SKIES AND LIGHT WINDS...LOWS WILL LIKELY DROP INTO THE
LOW TO MID 30S ACROSS MUCH OF THE FORECAST AREA. SOUTHWEST RETURN
FLOW FINALLY SETS UP SATURDAY...ALONG WITH PLENTY OF SUNSHINE AND
HIGHS IN THE LOWER 70S.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 329 PM EDT THU MAY 21 2015
THE MAIN STORY IN THE LONG TERM PERIOD IS THAT WE WILL FINALLY SEE
WARMER TEMPERATURES AS THE PERSISTENT HUDSON BAY UPPER LOW RETREATS
AND WE GET INTO DEEP SOUTHWEST FLOW. HIGHS IN THE 70S ARE LIKELY
AWAY FROM LK MI... WITH PERHAPS 80 DEGREES AND NOTICEABLY MORE HUMID
FROM MONDAY ON.
PROLONGED WARM ADVECTION PATTERN WITH A FLOW OFF THE GULF AND A
QUASI STATIONARY FRONTAL BOUNDARY WILL LIKELY LEAD TO ROUNDS OF
SHOWERS AND POSSIBLE TSTMS. HOWEVER THE TIMING/LOCATION/DURATION OF
CONVECTIVE EPISODES AND DAILY POSITION OF THE SFC FRONT IS LOW
CONFIDENCE AT THIS TIME. CURRENTLY WE HAVE THE HIGHEST POPS ON
SUNDAY NIGHT AND MONDAY WHICH IS WHEN THE SFC WARM FRONT IS LIFTING
NORTH THROUGH THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 726 PM EDT THU MAY 21 2015
BAND OF SHOWERS WILL DROP SOUTHEAST THROUGH THE TAF SITES THIS
EVENING RESULTING IN A WIND SHIFT. VFR WEATHER IS FORECASTED TO
PREVAIL...AND A FEW GUSTS OVER 20 KNOTS COULD ACCOMPANY THE
PASSAGE OF THESE SHOWERS. HIGH PRESSURE MOVES IN FOR FRIDAY AND
THAT WILL HELP TO KEEP CONDITIONS VFR.
&&
.MARINE...
ISSUED AT 329 PM EDT THU MAY 21 2015
BREEZY WESTERLY WINDS WILL CONTINUE THIS AFTERNOON WITH WAVES IN
THE 1 TO 3 FOOT RANGE. SCATTERED LIGHT SHOWERS WILL BE POSSIBLE
LATE THIS AFTERNOON AND EVENING. WINDS ARE EXPECTED TO SUBSIDE
AND VEER NORTHERLY BEHIND A WEAK COLD FRONT OVERNIGHT. WAVES WILL
BE 1 TO 2 FEET. NORTHERLY WINDS OF 5 TO 10 KNOTS ON FRIDAY WITH
WAVES AROUND 1 FOOT. FRIDAY WILL FEATURE PLENTY OF SUNSHINE BUT
STILL COOLER THAN NORMAL TEMPS. WINDS WILL TURN SOUTHWESTERLY ON
SATURDAY IN THE 5 TO 15 KNOT RANGE WITH WAVES AROUND 1 FOOT.
&&
.HYDROLOGY...
ISSUED AT 1240 PM EDT THU MAY 21 2015
NO CONCERNS THROUGH THE WEEKEND. PRECIPITATION THAT COULD AFFECT
MAINSTEM RIVERS IS NOT EXPECTED UNTIL LATE SUNDAY...WHICH MARKS THE
START OF A WETTER PATTERN LASTING WELL INTO THE COMING WORK WEEK.
NATIONAL GUIDANCE ADVERTISES UNIFORM RAINFALL TOTALS OF 1-1.5
INCHES ACROSS THE AREA THROUGH THURSDAY MORNING. GIVEN THAT BASE
FLOWS ARE NEAR OR BELOW NORMAL AND THAT RAIN SHOULD BE SPREAD OUT
OVER TIME...WE EXPECT FAIRLY GENTLE RISES WILL BE UNDERWAY BY THE
MIDDLE OF NEXT WEEK.
THAT SAID...FORECASTING CONVECTIVE RAINFALL THIS FAR OUT IS
HIGHLY UNCERTAIN SO THERE STILL REMAINS A FAIRLY WIDE RANGE OF
POSSIBILITIES FOR RAINFALL AND RIVER RESPONSES AT THIS POINT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 3 AM TO 9 AM EDT FRIDAY FOR MIZ037>040-
043>046.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...EBW
LONG TERM...MEADE
AVIATION...MJS
HYDROLOGY...TJT
MARINE...EBW
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
604 PM EDT WED MAY 20 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 329 PM EDT WED MAY 20 2015
COOLER THAN NORMAL WEATHER WILL CONTINUE THE REST OF THE WORK
WEEK...WITH FROST A GOOD BET EACH NIGHT ACROSS PORTIONS OF CENTRAL
LOWER MICHIGAN. SOME LIGHT RAIN SHOWERS OR SPRINKLES ARE POSSIBLE
ALONG INTERSTATE 94 THIS EVENING INTO TONIGHT. ANY RAINFALL AMOUNTS
WILL BE VERY LIGHT. AFTER A DRY AND PARTLY TO MOSTLY SUNNY DAY ON
THURSDAY SOME LIGHT RAIN SHOWERS WILL MOVE THROUGH THE AREA THURSDAY
NIGHT ALONG AND AHEAD OF A COLD FRONTAL PASSAGE. WARMER AIR WILL
MOVE IN FOR THE HOLIDAY WEEKEND WITH CHANCES FOR SHOWERS AND STORMS
RETURNING FOR SUNDAY INTO MEMORIAL DAY. HIGHS WILL REMAIN IN THE 60S
THE REST OF THE WORK WEEK RISING INTO THE 70S FOR SUNDAY AND
MEMORIAL DAY.
&&
.UPDATE...
ISSUED AT 604 PM EDT WED MAY 20 2015
ADDED CHANCE OF A MIX OF LIGHT RAIN AND SLEET TO THE FORECAST
THIS EVENING ACROSS THE SOUTHERN CWA PER NUMEROUS REPORTS OF A
RAIN/SLEET MIX IN THE CHICAGO AREA. AFTER THE PRECIP MOVED
IN...SOUTH HAVEN DROPPED TO 41 DEGREES REPORTING UP. THE FORECAST
IS DRY AFTER 06Z.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 329 PM EDT WED MAY 20 2015
SHORT TERM FOCUS WAS ON CHANCES FOR RAIN IN THE SOUTH THIS
EVENING...FROST POTENTIAL ACROSS CENTRAL LOWER MI TONIGHT AND THE
CHANCE FOR RAIN THURSDAY NIGHT WITH THE NEXT FRONT.
DECIDED TO ADD A MENTION OF LIGHT RAIN SHOWERS ALONG INTERSTATE 94
THIS EVENING AFTER ALL. HI-RES MODELS LIKE THE HRRR CONTINUE TO
INDICATE RAIN MAKING IT INTO OUR CWA...AND UPSTREAM RADAR TRENDS
WOULD AGREE. THAT SAID DRY AIR OVER LOWER MICHIGAN WILL TRY TO ERODE
IT AS IT MOVES IN. DEW POINT DEPRESSIONS AT THE SURFACE ACROSS THE
GRR CWA ARE IN EXCESS OF 20F IN MOST AREAS. PRECIP IS JUST TOO CLOSE
AT THIS POINT TO IGNORE. HAVE 20 PCT WORDING ALONG I-94 FOR NOW. WE
WILL BE WATCHING TO SEE IF IT MAKES IT INTO THE CWA AS WELL AS IF IT
TRENDS FURTHER NORTH TOWARDS I-96 WHICH THE HRRR CONTINUES TO SHOW
AS WELL.
OPTED TO ISSUE A FROST ADVISORY ACROSS THE FAR NORTHERN ROW OF
COUNTIES ALONG U.S. 10. CLOUDS WILL CLEAR OUT UP THERE OVERNIGHT
WITH VERY DRY AIR IN PLACE. VERY COLD READINGS OCCURRED LAST NIGHT
UP THERE AND THE AIR MASS HAS NOT CHANGED. FROST AND FREEZING
TEMPERATURES WILL BE POSSIBLE THE NEXT COUPLE NIGHTS UP THERE AS
WELL...THURSDAY NIGHT AND FRIDAY NIGHT.
A COLD FRONT WILL SWING THROUGH LOWER MICHIGAN THURSDAY NIGHT WITH
ALL OF THE SHORT TERM MODELS KICKING OUT SOME LIGHT PRECIPITATION.
THE COLD FRONT IS ASSOCIATED WITH AN UPPER LOW DRIFTING SOUTHEAST
ACROSS ONTARIO. MAY BE JUST ENOUGH MOISTURE AND LIFT FOR A FEW
SHOWERS. WILL CARRY 30 PCT CHANCES FOR RAIN THURSDAY NIGHT.
OTHERWISE QUIET WEATHER IS EXPECTED DURING THE DAY ON THURSDAY AND
AGAIN FRIDAY AND FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 329 PM EDT WED MAY 20 2015
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE LATE
SUNDAY THROUGH WEDNESDAY. THE WEATHER WILL TREND WARMER AND MORE
HUMID THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK.
SATURDAY IS SHAPING UP TO BE A BEAUTIFUL DAY WITH SURFACE HIGH
PRESSURE SLIDING OFF TO THE SOUTHEAST AND AN UPPER RIDGE BUILDING
INTO THE GREAT LAKES REGION. SOUTHWESTERLY RETURN FLOW SETS UP ON
SATURDAY...AND LOWER MICHIGAN WILL FINALLY START TO WARM UP AFTER A
COOL WEEK. HIGHS SHOULD BE AROUND 70 ON SATURDAY.
TEMPS WILL BE WARMER STILL ON SUNDAY AS A WARM FRONT APPROACHES FROM
THE SOUTH. TIMING DIFFERENCES EXIST BETWEEN THE LATEST GFS AND EURO.
THE 12Z EURO KEEPS SW LOWER MI MOSTLY DRY ON SUNDAY...WITH PERHAPS
SOME LIGHT RAIN MOVING INTO THE EXTREME SW CWA SUNDAY EVENING. THE
GFS IS MUCH WETTER SUNDAY. I WOULD DEFINITELY FAVOR A DRY SUNDAY
MORNING WITH PRECIP CHANCES INCREASING SUNDAY EVENING AND ESPECIALLY
SUNDAY NIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY NIGHT
THROUGH WEDNESDAY...WITH SOME BREAKS IN THERE OF COURSE. CONFIDENCE
IN SEVERE WEATHER IS LOW AT THIS TIME...BUT SOME INSTABILITY DOES
DEVELOP MONDAY AFTERNOON AND EVENING PRIMARILY SOUTH OF I-96 ALONG
WITH 30-40 KNOTS OF 0-6 KM BULK SHEAR. HIGHS MONDAY THROUGH
WEDNESDAY OF NEXT WEEK SHOULD BE IN THE MID TO UPPER 70S. 80
DEGREES SEEMS POSSIBLE ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 154 PM EDT WED MAY 20 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THURSDAY AFTERNOON.
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE WEST THIS
AFTERNOON AS AN UPPER WAVE OF LOW PRESSURE SWINGS INTO THE WESTERN
GREAT LAKES. CONSIDERABLE MID CLOUDS CAN BE EXPECTED AFTER 23Z
THIS EVENING...BASED BETWEEN 5 KFT AND 7KFT. SCATTERED CLOUDS
BELOW 5 KFT ARE POSSIBLE AFTER 00Z AT AZO/BTL/JXN.
IN ADDITION...A BAND OF LIGHT RAIN IS EXPECTED TO MOVE ACROSS
SOUTHERN LOWER MICHIGAN MAINLY BETWEEN 23Z AND 04Z THIS EVENING.
RAIN SHOWERS ARE EXPECTED TO ERODE SOMEWHAT AS THEY MOVE EAST INTO
LOWER MICHIGAN. FAIR AMOUNT OF UNCERTAINTY...SO INCLUDED VCSH AT
AZO/BTL. BOTTOM LINE...LIGHT RAIN SHOWERS ARE A POSSIBILITY AT
AZO/BTL/JXN AFTER 23Z...BUT CIGS AND VSBYS ARE EXPECTED TO REMAIN
VFR.
&&
.MARINE...
ISSUED AT 329 PM EDT WED MAY 20 2015
NOT EXPECTING SIGNIFICANT WINDS OR WAVES THE NEXT SEVERAL DAYS.
WINDS WILL COME UP A BIT THIS EVENING FROM HOLLAND SOUTH AND THEN
AGAIN THURSDAY AFTERNOON AND EVENING AHEAD OF A COLD FRONTAL
PASSAGE. IN BOTH CASES EXPECTING WINDS AND WAVES TO REMAIN BELOW
SMALL CRAFT ADVISORY THRESHOLDS. WAVES MAY RISE INTO THE 2-3 FOOT
RANGE DURING THE AFOREMENTIONED TIMES.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT THURSDAY FOR MIZ037>040.
LM...NONE.
&&
$$
UPDATE...EBW
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...EBW
AVIATION...EBW
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
329 PM EDT WED MAY 20 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 329 PM EDT WED MAY 20 2015
COOLER THAN NORMAL WEATHER WILL CONTINUE THE REST OF THE WORK
WEEK...WITH FROST A GOOD BET EACH NIGHT ACROSS PORTIONS OF CENTRAL
LOWER MICHIGAN. SOME LIGHT RAIN SHOWERS OR SPRINKLES ARE POSSIBLE
ALONG INTERSTATE 94 THIS EVENING INTO TONIGHT. ANY RAINFALL AMOUNTS
WILL BE VERY LIGHT. AFTER A DRY AND PARTLY TO MOSTLY SUNNY DAY ON
THURSDAY SOME LIGHT RAIN SHOWERS WILL MOVE THROUGH THE AREA THURSDAY
NIGHT ALONG AND AHEAD OF A COLD FRONTAL PASSAGE. WARMER AIR WILL
MOVE IN FOR THE HOLIDAY WEEKEND WITH CHANCES FOR SHOWERS AND STORMS
RETURNING FOR SUNDAY INTO MEMORIAL DAY. HIGHS WILL REMAIN IN THE 60S
THE REST OF THE WORK WEEK RISING INTO THE 70S FOR SUNDAY AND
MEMORIAL DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 329 PM EDT WED MAY 20 2015
SHORT TERM FOCUS WAS ON CHANCES FOR RAIN IN THE SOUTH THIS
EVENING...FROST POTENTIAL ACROSS CENTRAL LOWER MI TONIGHT AND THE
CHANCE FOR RAIN THURSDAY NIGHT WITH THE NEXT FRONT.
DECIDED TO ADD A MENTION OF LIGHT RAIN SHOWERS ALONG INTERSTATE 94
THIS EVENING AFTER ALL. HI-RES MODELS LIKE THE HRRR CONTINUE TO
INDICATE RAIN MAKING IT INTO OUR CWA...AND UPSTREAM RADAR TRENDS
WOULD AGREE. THAT SAID DRY AIR OVER LOWER MICHIGAN WILL TRY TO ERODE
IT AS IT MOVES IN. DEW POINT DEPRESSIONS AT THE SURFACE ACROSS THE
GRR CWA ARE IN EXCESS OF 20F IN MOST AREAS. PRECIP IS JUST TOO CLOSE
AT THIS POINT TO IGNORE. HAVE 20 PCT WORDING ALONG I-94 FOR NOW. WE
WILL BE WATCHING TO SEE IF IT MAKES IT INTO THE CWA AS WELL AS IF IT
TRENDS FURTHER NORTH TOWARDS I-96 WHICH THE HRRR CONTINUES TO SHOW
AS WELL.
OPTED TO ISSUE A FROST ADVISORY ACROSS THE FAR NORTHERN ROW OF
COUNTIES ALONG U.S. 10. CLOUDS WILL CLEAR OUT UP THERE OVERNIGHT
WITH VERY DRY AIR IN PLACE. VERY COLD READINGS OCCURRED LAST NIGHT
UP THERE AND THE AIR MASS HAS NOT CHANGED. FROST AND FREEZING
TEMPERATURES WILL BE POSSIBLE THE NEXT COUPLE NIGHTS UP THERE AS
WELL...THURSDAY NIGHT AND FRIDAY NIGHT.
A COLD FRONT WILL SWING THROUGH LOWER MICHIGAN THURSDAY NIGHT WITH
ALL OF THE SHORT TERM MODELS KICKING OUT SOME LIGHT PRECIPITATION.
THE COLD FRONT IS ASSOCIATED WITH AN UPPER LOW DRIFTING SOUTHEAST
ACROSS ONTARIO. MAY BE JUST ENOUGH MOISTURE AND LIFT FOR A FEW
SHOWERS. WILL CARRY 30 PCT CHANCES FOR RAIN THURSDAY NIGHT.
OTHERWISE QUIET WEATHER IS EXPECTED DURING THE DAY ON THURSDAY AND
AGAIN FRIDAY AND FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 329 PM EDT WED MAY 20 2015
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE LATE
SUNDAY THROUGH WEDNESDAY. THE WEATHER WILL TREND WARMER AND MORE
HUMID THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK.
SATURDAY IS SHAPING UP TO BE A BEAUTIFUL DAY WITH SURFACE HIGH
PRESSURE SLIDING OFF TO THE SOUTHEAST AND AN UPPER RIDGE BUILDING
INTO THE GREAT LAKES REGION. SOUTHWESTERLY RETURN FLOW SETS UP ON
SATURDAY...AND LOWER MICHIGAN WILL FINALLY START TO WARM UP AFTER A
COOL WEEK. HIGHS SHOULD BE AROUND 70 ON SATURDAY.
TEMPS WILL BE WARMER STILL ON SUNDAY AS A WARM FRONT APPROACHES FROM
THE SOUTH. TIMING DIFFERENCES EXIST BETWEEN THE LATEST GFS AND EURO.
THE 12Z EURO KEEPS SW LOWER MI MOSTLY DRY ON SUNDAY...WITH PERHAPS
SOME LIGHT RAIN MOVING INTO THE EXTREME SW CWA SUNDAY EVENING. THE
GFS IS MUCH WETTER SUNDAY. I WOULD DEFINITELY FAVOR A DRY SUNDAY
MORNING WITH PRECIP CHANCES INCREASING SUNDAY EVENING AND ESPECIALLY
SUNDAY NIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY NIGHT
THROUGH WEDNESDAY...WITH SOME BREAKS IN THERE OF COURSE. CONFIDENCE
IS SEVERE WEATHER IS LOW AT THIS TIME...BUT SOME INSTABILITY DOES
DEVELOP MONDAY AFTERNOON AND EVENING PRIMARILY SOUTH OF I-96 ALONG
WITH 30-40 KNOTS OF 0-6 KM BULK SHEAR. HIGHS MONDAY THROUGH
WEDNESDAY OF NEXT WEEK SHOULD BE IN THE MID TO UPPER 70S. 80 DEGREES
SEEMS POSSIBLE ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 154 PM EDT WED MAY 20 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THURSDAY AFTERNOON.
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE WEST THIS
AFTERNOON AS AN UPPER WAVE OF LOW PRESSURE SWINGS INTO THE WESTERN
GREAT LAKES. CONSIDERABLE MID CLOUDS CAN BE EXPECTED AFTER 23Z
THIS EVENING...BASED BETWEEN 5 KFT AND 7KFT. SCATTERED CLOUDS
BELOW 5 KFT ARE POSSIBLE AFTER 00Z AT AZO/BTL/JXN.
IN ADDITION...A BAND OF LIGHT RAIN IS EXPECTED TO MOVE ACROSS
SOUTHERN LOWER MICHIGAN MAINLY BETWEEN 23Z AND 04Z THIS EVENING.
RAIN SHOWERS ARE EXPECTED TO ERODE SOMEWHAT AS THEY MOVE EAST INTO
LOWER MICHIGAN. FAIR AMOUNT OF UNCERTAINTY...SO INCLUDED VCSH AT
AZO/BTL. BOTTOM LINE...LIGHT RAIN SHOWERS ARE A POSSIBILITY AT
AZO/BTL/JXN AFTER 23Z...BUT CIGS AND VSBYS ARE EXPECTED TO REMAIN
VFR.
&&
.MARINE...
ISSUED AT 329 PM EDT WED MAY 20 2015
NOT EXPECTING SIGNIFICANT WINDS OR WAVES THE NEXT SEVERAL DAYS.
WINDS WILL COME UP A BIT THIS EVENING FROM HOLLAND SOUTH AND THEN
AGAIN THURSDAY AFTERNOON AND EVENING AHEAD OF A COLD FRONTAL
PASSAGE. IN BOTH CASES EXPECTING WINDS AND WAVES TO REMAIN BELOW
SMALL CRAFT ADVISORY THRESHOLDS. WAVES MAY RISE INTO THE 2-3 FOOT
RANGE DURING THE AFOREMENTIONED TIMES.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT THURSDAY FOR MIZ037>040.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...EBW
AVIATION...EBW
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
154 PM EDT WED MAY 20 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 326 AM EDT WED MAY 20 2015
EXPECT BELOW NORMAL TEMPERATURES THROUGH AT LEAST SATURDAY AS A
SERIES OF CANADIAN COLD FRONTS COME THROUGH THE AREA. THE NEXT
COLD FRONT COMES THROUGH EARLY FRIDAY MORNING AND THAT WILL BE
PRECEDED BY A FEW LIGHT RAIN SHOWERS THURSDAY EVENING. A WARM UP
IS EXPECTED TOWARD MEMORIAL DAY. SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SUNDAY INTO TUESDAY.
&&
.UPDATE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
UPSTREAM SHORTWAVE SLIDING EAST FROM THE PLAINS WILL SPREAD CLOUDS
INTO SOUTHWEST LOWER MICHIGAN THIS AFTERNOON AND EVENING. SKIES IN
MOST AREAS WILL TURN MOSTLY CLOUDY WITH TIME. DILEMMA IS WHETHER
OR NOT WE WILL SEE PRECIPITATION INTO THE SOUTHERN PORTION OF THE
STATE. MORNING RUNS OF THE HRRR ARE TRYING TO BRING LIGHT RETURNS
INTO ABOUT THE SOUTHERN HALF OF THE GRR FORECAST AREA THIS EVENING.
AT THIS POINT HAVE DECIDED TO KEEP THE DRY FORECAST GOING AS WE
BELIEVE THE DRY AIR IS GOING TO WIN OUT. PRECIP UPSTREAM IS LIGHT
AND MAINLY FALLING OUT OF A MID DECK ON THE LEADING EDGE. IF THE
SYSTEM OVERPERFORMS IT WOULD BE IN THE FORM OF SPRINKLES ALONG
I-94 BETWEEN 800PM AND MIDNIGHT OR SO.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
LITTLE QUESTION THE PRECIPITATION EVENT ASSOCIATED WITH THE NEXT
SYSTEM WILL PASS SOUTH OF LOWER MICHIGAN THIS AFTERNOON AND
EVENING. THEN... ANOTHER DIGGING POLAR JET CORE FROM NORTHERN
CANADA WILL PUSH ANOTHER COLD FRONT THROUGH THE AREA LATER
THURSDAY NIGHT OR EARLY FRIDAY. THERE IS JUST MOIST LOW TO MID
LEVEL MOISTURE TO GET A FEW RAIN SHOWERS AHEAD OF THE COLD FRONT.
BEYOND THAT A CANADIAN HIGH MOVES IN BY MID MORNING FRIDAY
ASSURING MOSTLY CLEAR SKIES BUT COOLER TEMPERATURES. SOME FROST
WILL BE POSSIBLE SATURDAY MORNING.
EARLY THIS WEDNESDAY MORNING WE HAVE A SOUTHERN STREAM SYSTEM
CAUSING AN AREA OF RAIN AND THUNDERSTORMS NEAR THE MISSISSIPPI
RIVER. IT IS CURRENTLY HEADING EASTWARD AND WOULD NORMALLY
BRING RAIN TO OUR AREA TODAY. HOWEVER THIS TIME WE HAVE A
DIGGING NORTHERN STREAM SHORTWAVE AND ASSOCIATED POLAR JET CORE
HEADING FOR THE WESTERN GREAT LAKES. THAT WILL FORCE THE SOUTHERN
STREAM SYSTEM SOUTH OF MICHIGAN THIS AFTERNOON AND EVENING. WE
WILL SEE CONSIDERABLE HIGH AND MID CLOUDS TODAY WITH AREAS NEAR
I-94 SEEING THE THICKER CLOUDS WHILE AREA NORTH OF I-96 WILL HAVE
CONSIDERABLE MORE SUNSHINE. EVEN SO IT WILL NOT GET ALL THAT WARM
TODAY...HIGHS SHOULD MOSTLY BE IN THE 50S. SOME CLEARING IS
EXPECTED TONIGHT WITH LIGHTER WINDS SO NORTHERN AREA COULD SEE A
LITTLE PATCHY FROST.
MEANWHILE A CLOSED...COLD CORE UPPER LOW...CURRENTLY NEAR BAFFIN`SISLAND
DROPS SOUTHWARD...REACHING SOUTHERN HUDSON BAY THURSDAY MORNING.
THIS WILL BRING ANOTHER COLD FRONT THROUGH THE AREA LATE THURSDAY
NIGHT. THERE WILL BE JUST ENOUGH LOW TO MID LEVEL MOISTURE AND
LIFT AHEAD OF THE COLD FRONT TO CREATE A LIGHT RAIN SHOWERS.
CLEARING WILL QUICKLY FOLLOW BY MID MORNING FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
TWO MAIN CONCERNS IN THE EXTENDED...FIRST IS THE FROST THREAT ON
FRIDAY NIGHT AND THEN STORMY WEATHER FROM SUNDAY THROUGH TUESDAY.
SFC HIGH MOVES EAST BY 12Z SATURDAY...BUT RETURN FLOW MAY NOT BE
STRONG ENOUGH TO PREVENT FREEZING TEMPS UP NORTH AND SOME FROST
ESPECIALLY ACROSS EASTERN ZONES.
ONCE THE HIGH DEPARTS SATURDAY NIGHT...RETURN FLOW STRENGTHENS
WITH WARMER AND MORE HUMID AIR RETURNING BY MONDAY. ISENTROPIC
ASCENT NORTH OF THE SFC WARM FRONT SHOULD BRING SHOWERS BY SUNDAY
MORNING AND A SERIES OF WEAK WAVES MOVING ALONG STALLED FRONT
WILL CONTINUE INTO TUESDAY. CONFIDENCE IS HIGH ON THE OVERALL
PATTERN ALTHOUGH THERE ARE THE USUAL DIFFERENCES IN THE DETAILS.
OVERALL THERE IS A HIGH CONFIDENCE OF SHOWERS AND A FEW
THUNDERSTORMS THROUGH THE PERIOD FROM SUNDAY TO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 154 PM EDT WED MAY 20 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THURSDAY AFTERNOON.
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE WEST THIS
AFTERNOON AS AN UPPER WAVE OF LOW PRESSURE SWINGS INTO THE WESTERN
GREAT LAKES. CONSIDERABLE MID CLOUDS CAN BE EXPECTED AFTER 23Z
THIS EVENING...BASED BETWEEN 5 KFT AND 7KFT. SCATTERED CLOUDS
BELOW 5 KFT ARE POSSIBLE AFTER 00Z AT AZO/BTL/JXN.
IN ADDITION...A BAND OF LIGHT RAIN IS EXPECTED TO MOVE ACROSS
SOUTHERN LOWER MICHIGAN MAINLY BETWEEN 23Z AND 04Z THIS EVENING.
RAIN SHOWERS ARE EXPECTED TO ERODE SOMEWHAT AS THEY MOVE EAST INTO
LOWER MICHIGAN. FAIR AMOUNT OF UNCERTAINTY...SO INCLUDED VCSH AT
AZO/BTL. BOTTOM LINE...LIGHT RAIN SHOWERS ARE A POSSIBILITY AT
AZO/BTL/JXN AFTER 23Z...BUT CIGS AND VSBYS ARE EXPECTED TO REMAIN
VFR.
&&
.MARINE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
WE WILL BE KEEPING AN EYE ON A CORE OF WIND THAT THE HRRR IS
TRYING TO DEVELOP DOWN THE SHORELINE SOUTH OF HOLLAND LATE THIS
AFTERNOON AND EVENING. CHANNELING/FUNNELING DOWN THE SHORELINE
BLUFFS ARE LIKELY THE REASON FOR THE WIND THAT IS SHOWING UP IN
THE MODELS. NORTHWEST WINDS OF 15-20 KNOTS OR SO DEVELOP WHICH
WILL LIKELY KICK THE WAVE FIELD UP A BIT. THINKING WE WILL STAY
BELOW SCA CRITERIA...BUT WORTH WATCHING THE SOUTH HAVEN PIER AND
BUOY OBS BETWEEN 300PM AND 900PM OR SO.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...OSTUNO
AVIATION...EBW
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1208 PM EDT WED MAY 20 2015
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 326 AM EDT WED MAY 20 2015
EXPECT BELOW NORMAL TEMPERATURES THROUGH AT LEAST SATURDAY AS A
SERIES OF CANADIAN COLD FRONTS COME THROUGH THE AREA. THE NEXT
COLD FRONT COMES THROUGH EARLY FRIDAY MORNING AND THAT WILL BE
PRECEDED BY A FEW LIGHT RAIN SHOWERS THURSDAY EVENING. A WARM UP
IS EXPECTED TOWARD MEMORIAL DAY. SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SUNDAY INTO TUESDAY.
&&
.UPDATE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
UPSTREAM SHORTWAVE SLIDING EAST FROM THE PLAINS WILL SPREAD CLOUDS
INTO SOUTHWEST LOWER MICHIGAN THIS AFTERNOON AND EVENING. SKIES IN
MOST AREAS WILL TURN MOSTLY CLOUDY WITH TIME. DILEMMA IS WHETHER
OR NOT WE WILL SEE PRECIPITATION INTO THE SOUTHERN PORTION OF THE
STATE. MORNING RUNS OF THE HRRR ARE TRYING TO BRING LIGHT RETURNS
INTO ABOUT THE SOUTHERN HALF OF THE GRR FORECAST AREA THIS EVENING.
AT THIS POINT HAVE DECIDED TO KEEP THE DRY FORECAST GOING AS WE
BELIEVE THE DRY AIR IS GOING TO WIN OUT. PRECIP UPSTREAM IS LIGHT
AND MAINLY FALLING OUT OF A MID DECK ON THE LEADING EDGE. IF THE
SYSTEM OVERPERFORMS IT WOULD BE IN THE FORM OF SPRINKLES ALONG
I-94 BETWEEN 800PM AND MIDNIGHT OR SO.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
LITTLE QUESTION THE PRECIPITATION EVENT ASSOCIATED WITH THE NEXT
SYSTEM WILL PASS SOUTH OF LOWER MICHIGAN THIS AFTERNOON AND
EVENING. THEN... ANOTHER DIGGING POLAR JET CORE FROM NORTHERN
CANADA WILL PUSH ANOTHER COLD FRONT THROUGH THE AREA LATER
THURSDAY NIGHT OR EARLY FRIDAY. THERE IS JUST MOIST LOW TO MID
LEVEL MOISTURE TO GET A FEW RAIN SHOWERS AHEAD OF THE COLD FRONT.
BEYOND THAT A CANADIAN HIGH MOVES IN BY MID MORNING FRIDAY
ASSURING MOSTLY CLEAR SKIES BUT COOLER TEMPERATURES. SOME FROST
WILL BE POSSIBLE SATURDAY MORNING.
EARLY THIS WEDNESDAY MORNING WE HAVE A SOUTHERN STREAM SYSTEM
CAUSING AN AREA OF RAIN AND THUNDERSTORMS NEAR THE MISSISSIPPI
RIVER. IT IS CURRENTLY HEADING EASTWARD AND WOULD NORMALLY
BRING RAIN TO OUR AREA TODAY. HOWEVER THIS TIME WE HAVE A
DIGGING NORTHERN STREAM SHORTWAVE AND ASSOCIATED POLAR JET CORE
HEADING FOR THE WESTERN GREAT LAKES. THAT WILL FORCE THE SOUTHERN
STREAM SYSTEM SOUTH OF MICHIGAN THIS AFTERNOON AND EVENING. WE
WILL SEE CONSIDERABLE HIGH AND MID CLOUDS TODAY WITH AREAS NEAR
I-94 SEEING THE THICKER CLOUDS WHILE AREA NORTH OF I-96 WILL HAVE
CONSIDERABLE MORE SUNSHINE. EVEN SO IT WILL NOT GET ALL THAT WARM
TODAY...HIGHS SHOULD MOSTLY BE IN THE 50S. SOME CLEARING IS
EXPECTED TONIGHT WITH LIGHTER WINDS SO NORTHERN AREA COULD SEE A
LITTLE PATCHY FROST.
MEANWHILE A CLOSED...COLD CORE UPPER LOW...CURRENTLY NEAR BAFFIN`SISLAND
DROPS SOUTHWARD...REACHING SOUTHERN HUDSON BAY THURSDAY MORNING.
THIS WILL BRING ANOTHER COLD FRONT THROUGH THE AREA LATE THURSDAY
NIGHT. THERE WILL BE JUST ENOUGH LOW TO MID LEVEL MOISTURE AND
LIFT AHEAD OF THE COLD FRONT TO CREATE A LIGHT RAIN SHOWERS.
CLEARING WILL QUICKLY FOLLOW BY MID MORNING FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
TWO MAIN CONCERNS IN THE EXTENDED...FIRST IS THE FROST THREAT ON
FRIDAY NIGHT AND THEN STORMY WEATHER FROM SUNDAY THROUGH TUESDAY.
SFC HIGH MOVES EAST BY 12Z SATURDAY...BUT RETURN FLOW MAY NOT BE
STRONG ENOUGH TO PREVENT FREEZING TEMPS UP NORTH AND SOME FROST
ESPECIALLY ACROSS EASTERN ZONES.
ONCE THE HIGH DEPARTS SATURDAY NIGHT...RETURN FLOW STRENGTHENS
WITH WARMER AND MORE HUMID AIR RETURNING BY MONDAY. ISENTROPIC
ASCENT NORTH OF THE SFC WARM FRONT SHOULD BRING SHOWERS BY SUNDAY
MORNING AND A SERIES OF WEAK WAVES MOVING ALONG STALLED FRONT
WILL CONTINUE INTO TUESDAY. CONFIDENCE IS HIGH ON THE OVERALL
PATTERN ALTHOUGH THERE ARE THE USUAL DIFFERENCES IN THE DETAILS.
OVERALL THERE IS A HIGH CONFIDENCE OF SHOWERS AND A FEW
THUNDERSTORMS THROUGH THE PERIOD FROM SUNDAY TO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 725 AM EDT WED MAY 20 2015
SOME MVFR CONDITIONS NEAR JXN THIS MORNING WITH CEILINGS AROUND
2500 FEET AGL AT TIMES. ELSEWHERE...VFR CONDITIONS EXPECTED
THROUGH TONIGHT WITH WINDS BELOW 10 KNOTS.
&&
.MARINE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
WE WILL BE KEEPING AN EYE ON A CORE OF WIND THAT THE HRRR IS
TRYING TO DEVELOP DOWN THE SHORELINE SOUTH OF HOLLAND LATE THIS
AFTERNOON AND EVENING. CHANNELING/FUNNELING DOWN THE SHORELINE
BLUFFS ARE LIKELY THE REASON FOR THE WIND THAT IS SHOWING UP IN
THE MODELS. NORTHWEST WINDS OF 15-20 KNOTS OR SO DEVELOP WHICH
WILL LIKELY KICK THE WAVE FIELD UP A BIT. THINKING WE WILL STAY
BELOW SCA CRITERIA...BUT WORTH WATCHING THE SOUTH HAVEN PIER AND
BUOY OBS BETWEEN 300PM AND 900PM OR SO.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION...UPDATE
NWS JACKSON MS
1045 AM CDT WED MAY 20 2015
.UPDATE...LATEST SATELLITE AND UPPER AIR ANALYSIS SHOWED THE REGION
UNDER THE INFLUENCE OF MEAN RIDGING WITH BETTER JET ENERGY WELL
NORTH OF THE REGION. THE REMANTS OF AN MCS THAT CROSSED THE OZARKS
EARLIER WAS NOTED ACROSS NORTHWEST MISSISSIPPI. THERE WAS SOME GOOD
UPPER DIFFLUENCE OVER THE OZARKS EARLIER THIS MORNING WITH THE
MCS...PUSHING TOWARD THE REGION. HOWEVER MEAN RIDGING HAD SHUNTED
THE MCS IN AREAL COVERAGE AS OF LATE THIS MORNING. LATEST SURFACE
ANALYSIS SHOWED A WARM FRONTAL BOUNDARY EXTENDING ACROSS THE NORTH
WITH AN IMPRESSIVE BAROCLINIC ZONE NORTH OF THE COLD FRONT FROM
NW ARKANSAS THROUGH SOUTHEAST OK TO NORTH TEXAS. THIS WILL HELP
TO FOCUS THE PRECIP IN THE NORTH. LATEST SOUNDING ANALYSIS SHOWED SOME
DECENT MIDLEVEL FLOW OVER SHV AND LZK OF 30-35 KNOTS...WHICH ALONG WITH
THE UPPER DIVERGENCE WILL PUSH ACROSS THE REGION. ALSO SOME GOOD LOW LEVEL
INFLOW. LAPSE RATES AT SHV WAS AROUND 6C. OUR SNDG SHOWED WEAK LAPSE RATES
WITH PWATS AROUND 1.6...WHICH ACCOUNTS FOR THE SUNNY SKIES ACROSS THE CENTRAL
AND SOUTH EARLIER THIS MORNING. LATEST HIRES MODELS SHOWS THAT MOST OF THE
CONCENTRATION OF COVECTION SHOULD BE CONCENTRATED IN THE NORTHWEST FOR THIS
AFTERNOON. THE HRRR TRIED TO GET SOME GOING INTO THE EAST FOR THIS AFTERNOON...
BUT WAS DISCOUNTED DUE TO THE OTHER HIRES MODELS FOCUSING MORE IN THE NORTHWEST FOR
THIS AFTERNOON...WHICH SEEMS SENSIBLE. HRRR SHOWS SOME LAPSE RATES
AROUND 6C WITH MIDLEVEL FLOW AROUND 25-35 KNOTS. SO WITH THE MCS TO
THE NORTH OF THE REGION...IT COULD SEND A BOUNDARY FOR A POSSIBLE
STRONG OR SEVERE STORM FOR THIS AFTERNOON GENERALLY ALONG AND NORTH
OF THE HIGHWAY 82 CORRIDOR. DUE TO THE ISOLATED NATURE WILL KEEP THE
HWO CLEAR FOR NOW. SO WITH THIS IN MIND WILL KEEP CLOSE TO CURRENT
POPS AND CURRENT HIGHS IN THE 80S LOOKS TO BE ON TRACK./17/
&&
.AVIATION...THE EARLY MORNING FOG/STRATUS HAS DISSIPATED AND THE
APPROACHING THUNDERSTORM COMPLEX HAS WEAKENED PRIOR TO MOVING INTO
OUR AREA. VFR CONDITIONS WERE BEING REPORTED AREAWIDE AT 13Z AND WL
CONT THROUGH 17Z. A FEW STORMS WL COME IN VCTY OF GLH AROUND 17Z AND
HI-RES MODELS SUGGEST TSTM ACTIVITY WL MOSTLY AFFECT THE HIGHWAY 82
CORRIDOR THIS AFTN. VFR CONDS SHOULD CONTINUE TO PREVAIL CNTRL AND S
UNTIL THIS EVENING. A COLD FRONT WL DROP SOUTH ACROSS THE AREA LATER
TONIGHT INTO EARLY THURSDAY MORNING RESULTING IN A GREATER CHANCE
FOR IFR CIGS/VSBYS WITH CONVECTION. /22/
&&
./PREVIOUS DISCUSSION...501 AM CDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
AN IMPRESSIVE BAROCLINIC ZONE EXTENDING FROM THE SRN/CNTRL PLAINS
EWD TO THE MID MS VALLEY IS SUPPORTING A LARGE SLOW-MOVING MCS
MOVING INTO THE ARKLATEX REGION. CURRENT ANALYSES INDICATE A DEEP
MOISTURE AXIS (1.9 PRECIPITABLE WATER AND 335+ H850 THETA-E)
EXTENDING INTO NW PORTIONS OF THE ARKLAMISS ALONG A SURFACE FRONTAL
BOUNDARY...BUT SOUTHEASTWARD DEVELOPMENT OF THE MCS IS BEING
HINDERED BY THE SUBTROPICAL RIDGE THAT CONTINUES TO DEFLECT THE BULK
OF ENERGY ASSOC WITH THE WESTERLIES NORTH OF THE FORECAST AREA.
IN SPITE OF THE LACK OF LARGE SCALE SUPPORT...UPWIND PROPAGATION
VECTORS AND LOW LEVEL MOISTURE TRANSPORT SUGGEST THAT NW/NRN PORTION
OF THE ARKLAMISS WILL GET SOME SHOWER/TSTM ACTIVITY LATER THIS
MORNING...WITH EASTERN PORTIONS OF THE REGION HOLDING OFF UNTIL LATE
MORNING/EARLY AFTERNOON AFTER SUBSTANTIAL HEATING. STRONGER LOW-MID
LEVEL FLOW (20-30KT) ALONG AND NORTH OF THE HIGHWAY 82 CORRIDOR
COULD SUPPORT ORGANIZED STRONG STORMS LATER TODAY...BUT AIRMASS
RECOVERY AND INSTABILITY ARE MORE IN QUESTION THERE DEPENDING ON HOW
THINGS EVOLVE THIS MORNING. AS YOU GO FARTHER SOUTH TOWARD THE
INTERSTATE 20 CORRIDOR...MOISTURE/INSTABILITY INCREASE BUT THE FLOW
DECREASES. GIVEN THE UNCERTAINTIES AND DEPENDENCE ON MESOSCALE
INFLUENCES...WILL HOLD OFF ON MENTIONING ANY POTENTIAL FOR SEVERE
WEATHER IN THE HWO/GRAPHICS FOR TODAY.
GOING INTO TONIGHT AND THURSDAY...A COLD FRONT WILL PUSH SOUTH
THROUGH THE AREA FOLLOWED BY LESS HUMID CONDITIONS AND DECREASING
SHOWER/TSTM CHANCES - WITH POPS EVENTUALLY BECOME CONFINED TO AREAS
ALONG AND SOUTH OF THE HWY 84 CORRIDOR BY THURSDAY EVENING. LOW
TEMPERATURES IN THE MID/UPPER 50S COULD BE COMMON BY FRIDAY MORNING
OVER NORTHERN PORTIONS OF THE FORECAST AREA. /EC/
.LONG TERM...FRIDAY THROUGH WEDNESDAY...FAIRLY DRY AND WARM
CONDITIONS WILL OCCUR LATE THIS WEEK THROUGH THE WEEKEND. THIS
OCCURS AS HIGH PRESSURE AT THE SFC MOVES INTO THE NORTHERN PART OF
THE CWA AND UPPER RIDGING TAKES HOLD. SOME AFTERNOON STORMS WILL BE
POSSIBLE BUT THE UPPER RIDGE AND SUBSEQUENT CAPPING SHOULD KEEP THIS
CONVECTION AT BAY. THE UPPER RIDGE WILL CONTINUE TO HAVE AN
INFLUENCE OVER OUR WEATHER HEADING INTO THE WORK WEEK BUT THE CENTER
OF IT SHOULD BE MOVING EAST OF THE AREA. THIS WILL OPEN SOME
POTENTIAL FOR A LITTLE MORE IN THE WAY OF MAINLY AFTERNOON SHOWERS
AND STORMS. HIGHS WILL GENERALLY BE IN THE LOWER TO MID 80S THROUGH
THE PERIOD WITH LOWS STARTING IN THE MID TO UPPER 60S AND REACHING
BACK INTO THE 70S. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 86 68 78 60 / 38 43 33 12
MERIDIAN 86 68 81 59 / 37 36 29 11
VICKSBURG 87 67 76 61 / 30 40 30 14
HATTIESBURG 89 70 86 64 / 34 25 43 24
NATCHEZ 86 69 79 61 / 30 26 41 19
GREENVILLE 85 62 72 58 / 51 50 21 8
GREENWOOD 84 62 73 57 / 49 47 16 7
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
17/22/EC/28
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
711 AM CDT Wed May 20 2015
.SHORT TERM: (Through Tonight)
Issued at 316 AM CDT Wed May 20 2015
A broad area of rain progresses across the forecast area today in
association with a wave of low pressure riding along a
quasistationary frontal boundary. The precipitation is forced and
maintained by a strong southerly H85 LLJ interacting with a
quasistationary boundary. Isolated embedded thunderstorms are
possible. The upper vort center behind the surface wave moves into
weakly confluent flow and merges with a separate vort center which
originates over Manitoba. The resulting trough forms over Iowa
tonight and moves to the east or slightly south of east. Surface
high pressure will have already spread into the forecast area by
this time and no additional precipitation is expected with the
trough overnight, although the slight increase in lift could
prolong any ongoing showers across the eastern forecast area
between 00-06z.
The forecast area remains on the cool side of a quasistationary
boundary today and extensive clouds/precip will limit insolation.
These unusually cool conditions might set or tie some climate
records. Please refer to the climate section below.
42
.LONG TERM: (Thursday through Tuesday)
Issued at 316 AM CDT Wed May 20 2015
High pressure remains in place on Thursday and Friday. An upper
ridge also builds over the central US on Friday then amplifies on
Saturday ahead of a deepening trough over the western half of the
US. Several disturbances lift through the trough between Saturday
and Monday. These disturbances should bring a period of unsettled
weather to the forecast area, especially between Sunday and
Tuesday. Similar to the last two weekends, day to day
precipitation chances will depend both on synoptic scale
shortwaves and on any MCVs which form upstream. Refinements are
likely. Temperatures begin to warm up again on Saturday when winds
become southerly around the retreating surface high. A more
noticeable jump in warmth is expected on Sunday after a warm
frontal passage.
42
&&
.AVIATION: (For the 12z TAFs through 12z Thursday Morning)
Issued at 705 AM CDT Wed May 20 2015
Have used extrapolation of current radar trends for onset of the
rain this morning, and the latest (10z) HRRR data to time the end
of the rain later this morning and early this afternoon. For
cig/vsby trends, it looks like a very atypical May day with MVFR
vsbys in rain/fog, and IFR to MVFR cigs developing in the steady
rainfall. I`ve gone with prevailing MVFR vsbys/IFR cigs in COU by midday
where low level saturation should be greatest due to the rain this
morning, but elsewhere I`ve kept cigs MVFR with the thinking that
rainfall will be somewhat less, and because NE winds will be
attempting to advect relatively drier low level air in from the
ridge to our north. This thinking dovetails fairly well with 06z
MAV guidance. Heading into tonight there is lots of
uncertainty...will the southward oozing of the surface ridge scour
out the residual low level moisture or will the moisture become
trapped beneath an inversion? Because of this, forecast specifics
trail off early this evening, and will let day shift take a crack
at this time period as we get a better feel for trends later this
afternoon.
Specifics for KSTL: Steady rain is expected to develop by mid
morning, with cigs/vsbys heading into MVFR category by midday.
Latest HRRR guidance suggests rain ending by mid afternoon, but
have maintained MVFR cigs into the evening due to saturation
produced by the rainfall. Some lingering MVFR vsbys in fog is also
anticipated for several hours after the rain ends.
Truett
&&
.CLIMATE:
Issued at 316 AM CDT Wed May 20 2015
Record cool high temperatures for May 20th are as follows.
St. Louis, MO....55/1924 (KSTL)
Columbia, MO.....57/1924 (KCOU)
Quincy, IL.......57/1967 (KUIN)
Farmington, MO...66/1954 (co-op station)
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
1050 PM EDT THU MAY 21 2015
.SYNOPSIS...
A COLD FRONT WILL SHIFT OFF THE COAST OVERNIGHT. COOLER HIGH
PRESSURE WILL BUILD INTO REGION FRIDAY AND CONTINUE INTO THE
WEEKEND. AS THE HIGH PRESSURE SHIFTS OFF THE COAST BY THE MIDDLE OF
NEXT WEEK HIGHER HUMIDITIES WILL RETURN TO THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM THURSDAY...NEAR-TERM UPDATE TO ADDRESS THE INCREASING
SHOWER ACTIVITY ACROSS THE CWA. WEAK SECONDARY LOW PRESSURE HAS
DEVELOPED ALONG AN OCCLUDING FRONT ACCORDING TO LATEST WPC
ANALYSIS...AND ALONG THIS BOUNDARY SHOWERS HAVE RE-FIRED LOCALLY.
00Z KGSO SOUNDING HAS SOME ELEVATED INSTABILITY FROM ABOUT 950MB UP
THROUGH 750MB...SO SURFACE CONVERGENCE ALONG THE FRONT COMBINED WITH
AT LEAST WEAK MID-LEVEL FORCING ON THE SOUTHERN PERIPHERY OF A
SHORTWAVE MOVING OFF TO THE NORTH WILL DRIVE SHOWERS OVERNIGHT.
SHALLOW INSTABILITY WILL PREVENT LIGHTNING. HIGH RES HRRR AND NSSL
WRF WERE ON THE RIGHT TRACK...AND HAVE LEANED ON THE HRRR HEAVILY
FOR THE OVERNIGHT. HAVE RAMPED POP UP TO CHC ACROSS THE CENTRAL AND
NORTHERN PORTIONS OF THE CWA...BUT BEST CHANCE WILL BE PRETTY MUCH
ALONG THE STATE LINE AS THE BOUNDARY SLOWLY SAGS SOUTHWARD. ANY
SHOWERS WILL ERODE LATE AS THEY HEAD EAST...AND THE DRY/COOL
ADVECTION BEGINS IN EARNEST.
WINDS EARLY WILL BE VARIABLE...BUT ARE EXPECTED TO INCREASE AS THE
FRONT PUSHES SOUTH AND A COOL SURGE DEVELOPS. NORTHERLY WINDS WILL
RISE TO 10 TO 15 MPH LATE...WHICH WILL HELP DRIVE LOWS INTO THE UPR
50S NORTH...LOW 60S IN THE SOUTH.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...AS THE FRONT EXITS THE FORECAST
REGION...COOLER DRY HIGH PRESSURE WILL MOVE IN. GFS AND NAM ARE
SHOWING THE PRECIPITABLE WATER VALUES FALLING TO A RANGE OF 0.5 TO
1 INCHES. THE HIGH PRESSURE CENTER WILL STAY TO THE NORTH DURING
THIS PERIOD. NO PRECIPITATION IS EXPECTED THROUGH THIS PERIOD AND
MAXIMUM TEMPERATURES ARE EXPECTED TO BE IN THE UPPER 70S FRIDAY
AND AROUND 80 ON SATURDAY. LOWS EACH NIGHT SHOULD BOTTOM OUT IN
THE MIDDLE 50S FRIDAY NIGHT AND THE UPPER 50S ON SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...SURFACE HIGH PRESSURE WILL BE CENTERED JUST
TO THE NORTH OF THE AREA AND WILL SHIFT OFF THE COAST BY THE
BEGINNING OF NEXT WEEK. THE AREA WILL SEE A RETURN OF ONSHORE
FLOW...A RETURN TO HIGHER HUMIDITIES...AND A WARM UP IN TEMPERATURES.
ALOFT A RIDGE STUBBORNLY HOLDS ON THROUGH ALMOST THURSDAY SO THE
CHANCES OF PRECIPITATION WILL BE MINIMAL THROUGH AT LEAST EARLY
TUESDAY AND MAYBE AN ISOLATED CHANCE OF A DIURNAL SHOWERS OR
THUNDERSTORMS BY LATE TUESDAY THROUGH THURSDAY. MAXIMUM TEMPERATURES
WILL REBOUND TO AROUND 90 BY TUESDAY AND REMAIN AT THOSE LEVELS
THROUGH THURSDAY. MINIMUM TEMPERATURES WILL BE IN THE LOWER 60S
ON SUNDAY NIGHT AND WILL SLOWLY RISE INTO THE UPPER 60S BY
WEDNESDAY NIGHT.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...THE COLD FRONT IS LOCATED EARLY THIS EVENING S OF
KMYR TO JUST S-SW OF KFLO. LINGERING MVFR LEVEL LOW CLOUDS CAN BE
EXPECTED THIS EVENING NEAR KILM WITH A SLIGHT CHANCE OF A MVFR
CIG THROUGH 03Z. OTHERWISE VFR LEVEL LOW CLOUDS WILL PERSIST INTO
THE EARLY MORNING HOURS AT THE COASTAL TERMINALS AND AT KFLO.
DESPITE GOOD SUBSIDENCE AND MOIST SOILS AT KLBT AND KILM NO FOG IS
EXPECTED AS N WINDS SHOULD HELP KEEP THE LOW LEVELS WELL MIXED.
AFTER 12Z EXPECT VFR/CLEAR SKIES BELOW 12K AS N-NE WINDS PREVAIL.
IN THE AFTERNOON SCT CUMULUS WILL DEVELOP AS WINDS BECOME LIGHT
NE-E.
EXTENDED OUTLOOK...VFR. MORNING FOG POSSIBLE MONDAY AND TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM THURSDAY...COLD FRONT IS SLOWLY DROPPING SOUTH ACROSS
THE WATERS...BUT IT WILL TAKE MUCH OF THE OVERNIGHT TO CLEAR THE
AREA TO THE SOUTH. WINDS HAVE RECENTLY TURNED TO THE NORTH AT
41013...AND THIS WILL BE THE TREND ACROSS THE SC WATERS DURING THE
NEXT SEVERAL HOURS. A NORTHERLY SURGE IS PROGGED TO DEVELOP BEHIND
THE FRONT...AND WINDS WILL INCREASE STEADILY UP TO AROUND 20 KTS
OVERNIGHT. LATEST MME GUIDANCE SHOWS 25 KTS AT 41013...BUT ONLY 15
KTS AT JMPN7. FOR THIS REASON HAVE PAINTED AN AVERAGE OF 20 KTS
ACROSS THE WATERS...AND KEPT SEAS AT 3-5 FT...JUST BELOW SCEC
CRITERIA. IT IS NOT OUT OF THE QUESTION HOWEVER...THAT A SCEC MAY BE
NEEDED LATE IN THE OVERNIGHT AND INTO FRIDAY MORNING.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...A COLD FRONT WILL HAVE PUSHED EAST OF THE
WATERS AND HIGH PRESSURE WILL BUILD OVER THE WATERS. WINDS WILL
BE FROM THE NORTH AT 15 TO 20 KNOTS ON FRIDAY MORNING AND WILL
SLOWLY WEAKEN TO 10 TO 15 KTS BY THE OF END FRIDAY AND REMAIN AT
THESE SPEEDS. WINDS WILL BEGIN THE DAY FROM THE NORTH AND WILL
VEER TO THE EAST BY SATURDAY. SEA HEIGHTS WILL START OUT AT 2 TO 4
FEET EARLY FRIDAY AND WILL SETTLE OUT AT 2 TO 3 FEET THROUGH
SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...HIGH PRESSURE WILL RULE THE COASTAL WATERS
WITH SOUTHEAST WINDS OF 10 KNOTS SLOWLY SHIFTING TO THE SOUTH AT
10 KNOTS BY TUESDAY. SEAS WILL REMAIN AT 2 TO 3 FEET FOR THE
ENTIRE FORECAST PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...DRH
LONG TERM...DRH
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
937 PM EDT THU MAY 21 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRIEFLY EXTEND INTO THE AREA TONIGHT. A WEAK
COLD FRONT WILL THEN SLIDE SOUTHEAST ACROSS THE REGION ON FRIDAY.
AN AREA OF HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
NOT MANY CHANGES FOR CURRENT UPDATE THIS EVENING. COLD FRONT IS
CONTINUING ITS SLOW BUT SURE PROGRESS THROUGH MICHIGAN PRODUCING
VERY LIGHT RETURNS ON THE RADAR WITH IT. PWATS ARE FORECASTED TO
BE AROUND 0.7" FRIDAY AND WITH ONLY WEAK SURFACE CONVERGENCE ALONG
THE FRONT SO THINK THE CHANCE OF RAIN IS LOW. LATEST HRRR AND RAP
HAVE LIGHT RETURNS IN MICHIGAN SLOWLY WEAKENING AS THEY APPROACH
OUR NORTHERN COUNTIES AND GIVEN MENTIONED ABOVE THIS IS NOT
SURPRISING. CURRENT FORECAST HAS SLIGHT CHANCE POPS FOR OUR
WESTERN ZONES WHICH SEEMS REASONABLE. DID TWEAK LOW TEMPERATURES
DOWN A BIT OVERNIGHT AS TEMPS HAVE QUICKLY STARTED TO FALL THIS
EVENING AS SKIES HAVE CLEARED AND THE SUN HAS GONE DOWN. THERE IS
ALSO A SLIGHT CHANCE OF FOG OVERNIGHT BUT LATEST KILN SOUNDING NOT
TO IMPRESSIVE FOR FOG. HAVE LEFT THE MENTION OUT OF THE GRIDS FOR
NOW.
PREV DISCUSSION ->
SHORT WAVE JUST NORTHWEST OF THE FORECAST AREA
WILL QUICKLY MOVE OFF TO THE EAST SOUTHEAST THIS EVENING. RADAR IS
SHOWING SOME LIGHT ECHOES MOVING ACROSS THE REGION AHEAD OF THIS
FEATURE. APPEARS THAT THIS IS GENERALLY SPRINKLES. SUBSIDENCE ON
THE BACK SIDE OF THE SHORT WAVE SHOULD ALLOW FOR CLEARING DURING
THE EVENING. WINDS WILL DIMINISH BUT NOT COMPLETELY DECOUPLE.
FORECAST LOWS WITHIN A DEGREE OR TWO OF MOS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
A WEAK COLD FRONT WILL BE IN NORTHERN OHIO AT THE BEGINNING OF THE
PERIOD. THIS WILL PROGRESS SOUTHEAST THROUGH THE DAY. THERE WILL
BE A BAND OF CLOUDS ASSOCIATED WITH THIS AND CANNOT RULE OUT A FEW
SHOWERS IN EASTERN COUNTIES. BUT CHANCE OF MEASURABLE
PRECIPITATION LOOKS TO BE NO MORE THAN A SLIGHT CHANCE. HIGH
PRESSURE WILL BUILD IN THROUGH THE REMAINDER OF THE PERIOD. FRIDAY
NIGHT WILL BE THE COOLEST TIME FRAME AS GOOD RADIATIONAL COOLING
CONDITIONS WILL SET UP. GENERALLY WENT SLIGHTLY BELOW GUIDANCE FOR
LOWS BOTH NIGHTS. STAYED NEAR A MOS BLEND FOR HIGHS EXCEPT IN
CENTRAL OHIO WHERE FORECAST LEANS TOWARDS THE COOLER NUMBERS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
DRY CONDITIONS WILL START OUT THE LONG TERM. HIGH PRESSURE WILL BE
SITUATED EAST OF THE AREA AND SOUTHERLY FLOW WILL ALLOW FOR
TEMPERATURES TO RISE INTO THE UPPER 70S TO LOW 80S ON SUNDAY. A FEW
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SUNDAY AFTERNOON
INTO SUNDAY NIGHT MAINLY ACROSS WESTERN AND NORTHERN PORTIONS OF THE
FA. A MORE UNSETTLED PATTERN WILL BE IN PLACE FOR MONDAY THROUGH
THURSDAY WITH SHOWER AND THUNDERSTORM CHANCES EACH DAY. HIGH
TEMPERATURES WILL GENERALLY BE IN THE 80S EACH DAY WITH LOW
TEMPERATURES IN THE 60S.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
LIGHT RAIN FROM AN UPPER LEVEL DISTURBANCE HAS PUSHED EAST THIS
EVENING WITH SKIES CLEARING FROM WEST TO EAST. AS SKIES CLEAR
THIS EVENING TEMPERATURES WILL START TO APPROACH THE DEWPOINT BY
FRIDAY MORNING. LATEST ROUND OF GUIDANCE NOT SHOWING MUCH IN THE
WAY OF FOG AS DEWPOINT DEPRESSIONS REMAIN A AROUND 2 TO 3 DEGREES.
A COLD FRONT WILL ALSO BE PUSHING SOUTH OVERNIGHT AND MOVE THROUGH
THE AREA FRIDAY AFTERNOON. USUALLY AHEAD OF A FRONT AND AFTER RAIN
FOG IS A CONCERN. GIVEN THAT THE FRONT IS MOVING THROUGH IN THE
AFTERNOON AND THE RAIN THAT WAS OBSERVED THURSDAY MORNING WAS VERY
LIGHT HAVE LEFT THE MENTION OF FOG/ REDUCED VISIBILITIES OUT OF
THE TAFS FOR NOW.
A COLD FRONT IS THEN EXPECTED TO PUSH THROUGH THE AREA FRIDAY
AFTERNOON WITH MOSTLY A DRY PASSAGE EXPECTED. HIGH RES MODELS ARE
SHOWING SOME VERY LIGHT RAIN ALONG THE FRONT BUT GIVEN FORECAST
SOUNDING PROFILES CHANCE IS TO LOW TO MENTION IN TAFS. MOST LIKELY
THERE WILL BE A BROAD AREA OF CU ASSOCIATED WITH THE FRONT AS
OBSERVED CURRENTLY ON VISIBLE SATELLITE UP IN WISCONSIN/ AND THE
UP OF MICHIGAN. MOSTLY VFR CONDITIONS EXPECTED WITH THE FRONTAL PASSAGE.
OUTLOOK...THUNDERSTORMS POSSIBLE MONDAY INTO TUESDAY...WITH MVFR
CIGS/VSBYS POSSIBLE.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HAINES
NEAR TERM...HAINES
SHORT TERM...
LONG TERM...NOVAK
AVIATION...HAINES
AREA FORECAST DISCUSSION
NWS TULSA OK
830 PM CDT THU MAY 21 2015
.DISCUSSION...
NEXT ROUND OF SHOWERS AND THUNDERSTORMS TO AFFECT EASTERN OKLAHOMA
AND WESTERN ARKANSAS WILL ENCROACH ON THE AREA FROM THE WEST TONIGHT
AND MAY ENTER THE WESTERN FRINGES OF THE COUNTY WARNING AREA BY 12Z.
ANOTHER MID-LEVEL SHORTWAVE WILL MOVE OUT OF SOUTHWEST UNITED STATES
TONIGHT AND ACROSS THE PLAINS ON FRIDAY BRINGING THE SHOWERS AND
THUNDERSTORMS TO THE AREA. HAVE LOWERED POPS EAST OF HIGHWAY 75 FOR TONIGHT
AS THE HRRR HAS TRENDED A BIT SLOWER ON BRINGING THE PRECIPITATION INTO
THE AREA. HAVE ALSO MADE SOME ADJUSTMENTS TO THE SKY GRIDS FOR TONIGHT.
OTHERWISE...CURRENT FORECAST IS ON TRACK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 7 AM MONDAY FOR OKZ049-
OKZ053-OKZ054-OKZ055-OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-
OKZ061-OKZ062-OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-
OKZ069-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076.
AR...FLASH FLOOD WATCH FROM 1 PM SUNDAY TO 7 AM MONDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011-ARZ019-ARZ020-ARZ029.
&&
$$
SHORT TERM...10
LONG TERM....99
AREA FORECAST DISCUSSION
NWS PORTLAND
951 AM PDT WED MAY 20 2015
.SYNOPSIS...A BROAD UPPER LEVEL LOW PRESSURE AND ONSHORE FLOW WILL
BRING A THREAT OF SHOWERS AND THUNDERSTORMS TO MAINLY THE CASCADES
TODAY AND THURSDAY. PLENTY OF LOW CLOUDS AND NEAR AVERAGE
TEMPERATURES WILL LINGER ALONG THE COAST AND IN THE WILLAMETTE
VALLEY. ANOTHER WEAK UPPER LEVEL LOW PRESSURE SLIDING DOWN FROM
BRITISH COLUMBIA MAY BRING A FEW AFTERNOON AND EVENING SHOWERS AND
POSSIBLY A THUNDERSTORM TO THE HIGHER TERRAIN FOR THE MEMORIAL DAY
WEEKEND.
&&
.SHORT TERM...WATER VAPOR SATELLITE IMAGERY THIS MORNING REVEALS A
BROAD UPPER LEVEL TROUGH LINGERING OVER THE EASTERN PACIFIC AND
WESTERN US. AN EMBEDDED SHORTWAVE TROUGH SITUATED OVER NORTHERN
CALIFORNIA CONTINUES TO PLACE THE PACIFIC NORTHWEST IN MID TO UPPER
LEVEL EASTERLY FLOW. SURFACE ANALYSIS SHOWS PRESSURE GRADIENTS
REMAINING ONSHORE...ALBEIT A BIT WEAKER THAN 24 HOURS AGO. AN
EXTENSIVE MARINE LAYER WITH PLENTY OF LOW CLOUDS EXISTS BELOW ABOUT
5000 FT ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON THIS
MORNING. AREAS OF DRIZZLE HAVE DEVELOPED ALONG THE COAST AND ALONG
THE LOWER COLUMBIA RIVER VALLEY. EXPECT MARINE CLOUDS TO BE A LITTLE
LESS STUBBORN TO BURN OFF THAN YESTERDAY...BUT NOT SURE ALL INTERIOR
VALLEYS WILL SEE SUNSHINE LATER THIS AFTERNOON EITHER. KEPT FORECAST
HIGH TEMPERATURES NEAR 70F FOR THE WILLAMETTE VALLEY...BUT IF MARINE
CLOUDS HOLD...THIS MAY BE A BIT HIGH BASED ON YESTERDAY.
MEANWHILE...THE MID TO UPPER LEVEL EASTERLY FLOW AND DAYTIME HEATING
WILL BRING A THREAT OF SHOWERS AND THUNDERSTORMS TO THE CASCADES
BEGINNING MIDDAY...AND PERSISTING INTO THIS EVENING. DEBRIS
CLOUDS FROM EARLIER CONVECTION ARE MOVING WESTWARD AND WILL MOVE OVER
THE NORTH OREGON CASCADES LATER THIS MORNING. THIS FEATURE SHOULD BE
ARRIVING EARLIER ENOUGH IN THE DAY THAT IT MAY END UP
INHIBITING...RATHER THAN ENHANCING...CONVECTION BETWEEN MOUNT
JEFFERSON AND MOUNT HOOD.
THE NAM AND GFS BOTH CONTINUE TO SUGGEST PLENTY OF CAPE WITH LITTLE
CONVECTIVE INHIBITION WILL DEVELOP OVER THE SOUTH WASHINGTON CASCADES
THIS AFTERNOON SO IT SEEMS SOME CONVECTION SHOULD DEVELOP IN THIS
REGION THIS AFTERNOON. HOWEVER...IT APPEARS THE MARINE LAYER WILL
REMAIN STRONG ENOUGH TO PREVENT VALLEY LOCATIONS FROM LIKELY GETTING
INTO THE ACTION WITH A NICE CAP INHIBITING CONVECTION.AS A
RESULT...THE MENTION OF THUNDER WAS REMOVED FROM TODAYS FORECAST.
NONETHELESS...SREF 12 HR THUNDER PROBABILITIES EXCEED 50 PERCENT FOR
THE WILLAMETTE VALLEY THIS EVENING. CANNOT IGNORE THIS SO RETAINED
THE SLIGHT CHANCE MENTION OF THUNDER FOR THIS EVENING IN THE NORTHERN
WILLAMETTE VALLEY AND LOWER COLUMBIA RIVER VALLEY.
STORM SCALE ENSEMBLE GUIDANCE AND THE LATEST HRRR RUNS DO SUGGEST
CONVECTION WILL BE MOST LIKELY TO DEVELOP OVER THE LANE AND LINN
COUNTY CASCADES THIS AFTERNOON AND EVENING...WHICH SEEMS PLAUSIBLE
GIVEN THIS REGIONS PROXIMITY TO THE MOISTURE AND INSTABILITY PRESENT
IN SOUTHERN OREGON. BOTH SETS OF GUIDANCE SUGGEST THERE IS A CHANCE
THESE SHOWERS AND THUNDERSTORMS COULD DRIFT WESTWARD OVER THE
SOUTHERN WILLAMETTE VALLEY THIS EVENING. HOWEVER...CONFIDENCE IN
THIS SCENARIO PANNING OUT IS STILL RELATIVELY LOW GIVEN THE MARINE
LAYER IN PLACE...AND NO STRONG UPPER LEVEL FORCING MECHANISMS HAVE
BEEN NOTED TO ALLOW FOR ELEVATED CONVECTION TO SUSTAIN ITSELF. IF THE
SOUTHERN VALLEY CLEARS EARLY THIS AFTERNOON...AND WARMS WELL INTO THE
70S THEN THESE SHORT TERM MODELS MAY BE ONTO SOMETHING...BUT AM
SKEPTICAL AT THIS POINT. WILL CONTINUE TO MONITOR TRENDS AND UPDATE
THE FORECAST ACCORDINGLY.
ADDITIONAL CONVECTION APPEARS POSSIBLE OVER THE CASCADES THURSDAY
AFTERNOON AND EVENING. ONSHORE PRESSURE GRADIENTS WILL INCREASE
THURSDAY NIGHT INTO FRIDAY...WHICH SHOULD RESULT IN ANOTHER EXTENSIVE
MARINE CLOUD LAYER DAY. AREAS OF MORNING DRIZZLE CERTAINLY APPEAR
POSSIBLE. ALTHOUGH...THE THREAT OF CONVECTION SHOULD SHIFT EAST OF
THE CASCADES ON FRIDAY...A LIGHT SHOWER OR TWO ACROSS THE WILLAMETTE
VALLEY OR IN THE CASCADES CANNOT BE RULED OUT AS THE MARINE LAYER
LIFTS WITH DAYTIME HEATING EACH DAY. /NEUMAN
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
FRIDAY NIGHT THROUGH TUESDAY...MODEL GUIDANCE CONTINUES TO REMAIN IN
GENERAL AGREEMENT FOR THE END OF THE WEEK WITH THE BLOCKING PATTERN
CONTINUING WITH HIGH PRESSURE OVER ALASKA AND WESTERN CANADA ABOVE
UPPER LOW PRESSURE SLOWLY SLIDING EAST ACROSS THE SOUTHWESTERN U.S.
AND GREAT BASIN. KEPT SOME SLIGHT CHANCE SHOWERS IN THE CASCADES FOR
THE WEEKEND WITH PERHAPS SHOWERS ATTEMPTING TO MAKE THEIR WAY INTO
THE FOOTHILLS OR EASTERN VALLEY...THOUGH CONFIDENCE IS LOW. HEIGHTS
MAY RISE A BIT FOR THE START OF THE WEEK THOUGH MODELS DIVERGE
CONSIDERABLY IN THE DETAILS SO CONFIDENCE REMAINS LOWER IN THE
SPECIFICS FOR THIS TIME. CULLEN
&&
.AVIATION...CONDITIONS ALONG THE COAST REMAIN MOSTLY IFR UNDER
ONSHORE FLOW WITH CIGS GENERALLY AOB 800 FT. EXPECT CONDITIONS TO
GRADUALLY IMPROVE TO MVFR WITH GUSTY WINDS POSSIBLE THIS
AFTERNOON/EVENING. HOWEVER...CIGS LOOK TO REMAIN AOB 2000 FT.
CONDITIONS INLAND REMAIN MOSTLY MVFR UNDER GENERALLY LIGHT AND
VARIABLE FLOW. CONDITIONS SHOULD IMPROVE TO VFR AFTER 18Z WITH
CIGS AROUND 4000 FT. THUNDERSTORMS WILL LIKELY REDEVELOP OVER THE
CASCADES THIS AFTERNOON AND COULD DRIFT OVER THE VALLEY...BUT
CONFIDENCE REMAINS TOO LOW TO INCLUDE IN THE 18Z TAF PACKAGE. MOST
LIKELY TIMES FOR THUNDERSTORMS IMPACTING INLAND TERMINALS WILL BE
BETWEEN 00Z-06Z THU.
KPDX AND APPROACHES...LOW-END MVFR CIGS EXPECTED THROUGH AROUND
20Z WITH CIGS GRADUALLY LIFTING OVER THE NEXT SEVERAL HOURS.
THERE IS A CHANCE THAT THUNDERSTORMS COULD DRIFT OVER THE
TERMINAL BETWEEN 00Z-06Z THU...BUT CONFIDENCE IS STILL TO LOW TO
INCLUDE IN THE 18Z TAF PACKAGE. /64
&&
.MARINE...SURFACE HIGH PRES OFFSHORE AND THERMAL LOW PRES OVER THE
INLAND NW SHOULD GIVE US RELATIVELY BENIGN WEATHER FOR THE NEXT
SEVERAL DAYS. WINDS SHOULD STAY BELOW 20 KT...BUT WOULD NOT BE
SURPRISED TO SEE ISOLATED GUSTS TO 25 KT IN THE AFTERNOON/EVENING
OVER THE OUTER WATERS. SEAS WILL HOVER BETWEEN 3 AND 6 FT OVER THE
FORECAST PERIOD. HOWEVER...STEEP AND CHOPPY SEAS CAN BE EXPECTED
AT TIMES DUE TO A FRESH NW SWELL. /64
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
258 AM EDT WED MAY 20 2015
.SYNOPSIS...
A SEASONABLY COOL AND MAINLY DRY WEATHER PATTERN WILL CONTINUE
INTO WEEKEND...FOLLOWED BY A GRADUAL WARMING TREND WITH UNSETTLED
CONDITIONS RETURNING EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR STLT SHOWS A PRETTY SOLID STRATOCUMULS CLOUD SHIELD COVERING
THE WRN 1/2 OF THE CWA EARLY THIS MORNING. THERE HAS EVEN BEEN
SOME LIGHT RAIN/SPRINKLES REPORTED AT BFD/OLE IN COOL UPSLOPE NW
FLOW REGIME. THE LOW CLOUDS ARE ASSOCIATED WITH A 850MB COOL POOL
ALOFT WHICH IS FCST TO MODERATE THROUGH THE AFTERNOON. WITH NO
SIGNIFICANT WX EXPECTED ON DAY 1 THE SENSIBLE WX FCST CHALLENGES
INVOLVE T/TD...SKY...WINDS AND RH VALUES WITH PERHAPS SOME
MARGINAL FIRE WX CONCERNS. WILL TAKE CLOSER LOOK AT THIS WITH THE
NEXT UPDATE...BUT FOR NOW LEANED ON THE HRRR WHICH HAS SUBJECTIVELY
PERFORMED BETTER THAN THE BLENDED MODEL DATA WITH DEWPOINTS AND
SUBSEQUENT RH/S. CLOUD COVER MAY BE CRITICAL KEEPING TEMPS LOWER
AND THUS RH/S HIGHER. BREEZY AND NOTICEABLY COOLER WILL DESCRIBE
TODAY QUITE WELL WITH HIGHS RUNNING 15 TO 20 DEGREES LOWER THAN
YESTERDAY...AND ABOUT 5 TO 15 DEGREES BELOW LATE MAY CLIMATOLOGY.
LOOK FOR CLOUDS TO INCREASE BY EARLY TONIGHT IN ADVANCE OF
SHORTWAVE TROUGH TRACKING THROUGH THE GREAT LAKES EMBEDDED WITHIN
LARGE SCALE UPPER TROUGH ANCHORING THE NORTHEASTERN SECTOR OF THE
CONTINENT. THE MODELS SEEM TO BE IN SLIGHTLY BETTER AGREEMENT IN
POSSIBLE SHOWERS DEVELOPING OVER SOUTH-CENTRAL PA LATE TONIGHT
INTO THURSDAY. THE PCPN ACTIVITY APPEARS TO BE TIED TO WAA
DOWNSTREAM OF HEIGHT FALL CENTER REACHING THE UPPER OH VLY. AS A
RESULT HAVE INCREASED POPS INTO THE LOW-MID CHC RANGE FOR THE
SOUTH-CENTRAL ZONES WITH THE HIGHEST POPS ALONG THE MD BORDER.
FINALLY...BLENDED MIN TEMPS ARE IN THE UPPER 30S OVER THE NW MTNS
BUT THE OVERALL PATTERN AND EXPECTED CLOUD COVER DOES NOT REALLY
SUPPORT FROST FORMATION.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
DAY 2/THURSDAY MAY END UP BEING THE COOLEST DAY OF THE WEEK AS
LOW CLOUDS PERSIST FOR MUCH OF THE DAY ACROSS SOUTH-CENTRAL PA.
GUIDANCE BLEND SUGGEST DAYTIME READINGS HOLDING IN THE 50S IN THE
LAUREL HIGHLANDS. PCPN CHANCES SHOULD LINGER ALONG THE SRN TIER
DURING THE DAY BEFORE DRIER AIR RETURNS TO CENTRAL PA BEHIND A
WEAK FRONTAL PASSAGE THU NGT. WINDS SHOULD PICK UP SOME THU NIGHT
BUT OVERALL EXPECT CLEARING SKIES FROM NW TO SE AND NO SIG WX.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A WEAK SFC LOW IS FCST TO EMERGE OFF THE CAROLINAS INTO FRIDAY
WITH SOME SPREAD IN THE GUIDANCE...OWING TO VARIABILITY IN THE
HANDLING OF THE PARENT SHORTWAVE. A SECONDARY COLD FRONT SHOULD
CROSS THE AREA ON FRIDAY FOLLOWED BY A REINFORCING SHOT OF COOL
AIR. CONFIDENCE REMAINS ON THE LOW SIDE FOR FROST THU MORNING IN
THE NORTH AS THE PATTERN DOES NOT LOOK FAVORABLE OR CONDUCIVE.
CONFIDENCE IN FROST POTENTIAL IS MUCH HIGHER ON SATURDAY MORNING
OVER THE NORTH-CNTRL ZONES WITH A LARGE AREA OF HIGH PRESSURE
FCST TO SETTLE OVER CENTRAL PA. MAINTAINED FROST WORDING IN SOME
NORTHERN ZONES. DRY WX SHOULD HOLD ON UNTIL EARLY NEXT WEEK AS
THE UPPER RIDGE BUILDS AGAIN OVER THE ERN U.S.
AN E-W FRONTAL BOUNDARY LOOKS TO BECOME A FOCUS FOR PCPN MON-TUE
AS IT PIVOTS AND LIFTS NWD IN A SIMILAR FASHION TO THIS PAST
WEEKEND. ALL GUIDANCE POINTS TO A GRADUAL WARMING TREND OVER THE
WEEKEND...WITH EVEN MILDER AND MORE MUGGY CONDITIONS STARTING
MEMORIAL DAY AND CONTINUING INTO NEXT WEEK.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
11 PM UPDATE...
THE AVIATION CONCERN OVERNIGHT AND INTO THE MONRING IS THE SHIELD
OF MVFR CEILINGS THAT ARE SPREADING OVER CENTRAL AND NORTHWEST PA.
CURRENTLY BFD AND JST ARE AT MVFR WITH BFD AT TIMES DOWN TO IFR IN
LOW STRATOCU. EXPECT MVFR TO SPREAD TO AOO...UNV AND IPT. HOWEVER
IFR IS LESS LIKELY CONSIDERING THE WINDS...BUT THIS DOWNSLOPE FLOW
TO THE LOWER SUSQ SHOULD KEEP SKIES MAINLY SCATTERED AND VFR. THE
PERSISTENT NORTHWESTERLY FLOW SHOULD KEEP ANY REDUCTION IN VSBYS.
LOW CEILINGS WILL MIX OUT AND LIFT QUICKLY THIS MORNING LEAVING
VFR CONDITIONS AT ALL SITES BY MID DAY. GUSTY WINDS WILL CONTINUE
IN THE NEIGHBORHOOD OF 10-15 KT OVERNIGHT BEFORE INCREASING ONCE
AGAIN WED TO 15-25 KT. HOWEVER AS THE WINDS SHIFT TO THE NORTH
LATER IN THE DAY...THE GUSTS WILL SUBSIDE AND WINDS WILL DECREASE
TO NEAR CALM BETWEEN 23Z TO 02Z THURSDAY.
OUTLOOK...
THU-FRI...NO SIG WX.
SUN...MAINLY VFR...MVFR POSS IN SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...RXR/STEINBUGL
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
209 AM EDT WED MAY 20 2015
.SYNOPSIS...
A SEASONABLY COOL AND MAINLY DRY WEATHER PATTERN WILL CONTINUE
INTO WEEKEND...FOLLOWED BY A GRADUAL WARMING TREND WITH UNSETTLED
CONDITIONS RETURNING EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR STLT SHOWS A PRETTY SOLID STRATOCUMULS CLOUD SHIELD COVERING
THE WRN 1/2 OF THE CWA EARLY THIS MORNING. THERE HAS EVEN BEEN
SOME LIGHT RAIN/SPRINKLES REPORTED AT BFD/OLE IN COOL UPSLOPE NW
FLOW REGIME. THE LOW CLOUDS ARE ASSOCIATED WITH A 850MB COOL POOL
ALOFT WHICH IS FCST TO MODERATE THROUGH THE AFTERNOON. WITH NO
SIGNIFICANT WX EXPECTED ON DAY 1 THE SENSIBLE WX FCST CHALLENGES
INVOLVE T/TD...SKY...WINDS AND RH VALUES WITH PERHAPS SOME
MARGINAL FIRE WX CONCERNS. WILL TAKE CLOSER LOOK AT THIS WITH THE
NEXT UPDATE...BUT FOR NOW LEANED ON THE HRRR WHICH HAS SUBJECTIVELY
PERFORMED BETTER THAN THE BLENDED MODEL DATA WITH DEWPOINTS AND
SUBSEQUENT RH/S. CLOUD COVER MAY BE CRITICAL KEEPING TEMPS LOWER
AND THUS RH/S HIGHER. BREEZY AND NOTICEABLY COOLER WILL DESCRIBE
TODAY QUITE WELL WITH HIGHS RUNNING 15 TO 20 DEGREES LOWER THAN
YESTERDAY...AND ABOUT 5 TO 15 DEGREES BELOW LATE MAY CLIMATOLOGY.
LOOK FOR CLOUDS TO INCREASE BY EARLY TONIGHT IN ADVANCE OF
SHORTWAVE TROUGH TRACKING THROUGH THE GREAT LAKES EMBEDDED WITHIN
LARGE SCALE UPPER TROUGH ANCHORING THE NORTHEASTERN SECTOR OF THE
CONTINENT. THE MODELS SEEM TO BE IN SLIGHTLY BETTER AGREEMENT IN
POSSIBLE SHOWERS DEVELOPING OVER SOUTH-CENTRAL PA LATE TONIGHT
INTO THURSDAY. THE PCPN ACTIVITY APPEARS TO BE TIED TO WAA
DOWNSTREAM OF HEIGHT FALL CENTER REACHING THE UPPER OH VLY. AS A
RESULT HAVE INCREASED POPS INTO THE LOW-MID CHC RANGE FOR THE
SOUTH-CENTRAL ZONES WITH THE HIGHEST POPS ALONG THE MD BORDER.
FINALLY...BLENDED MIN TEMPS ARE IN THE UPPER 30S OVER THE NW MTNS
BUT THE OVERALL PATTERN AND EXPECTED CLOUD COVER DOES NOT REALLY
SUPPORT FROST FORMATION.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
DAY 2/THURSDAY MAY END UP BEING THE COOLEST DAY OF THE WEEK AS
LOW CLOUDS PERSIST FOR MUCH OF THE DAY ACROSS SOUTH-CENTRAL PA.
GUIDANCE BLEND SUGGEST DAYTIME READINGS HOLDING IN THE 50S IN THE
LAUREL HIGHLANDS. PCPN CHANCES SHOULD LINGER ALONG THE SRN TIER
DURING THE DAY BEFORE DRIER AIR RETURNS TO CENTRAL PA BEHIND A
WEAK FRONTAL PASSAGE THU NGT. WINDS SHOULD PICK UP SOME THU NIGHT
BUT OVERALL EXPECT CLEARING SKIES FROM NW TO SE AND NO SIG WX.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A WEAK SFC LOW IS FCST TO EMERGE OFF THE CAROLINAS INTO FRIDAY
WITH SOME SPREAD IN THE GUIDANCE...OWING TO VARIABILITY IN THE
HANDLING OF THE PARENT SHORTWAVE. A SECONDARY COLD FRONT SHOULD
CROSS THE AREA ON FRIDAY FOLLOWED BY A REINFORCING SHOT OF COOL
AIR. CONFIDENCE REMAINS ON THE LOW SIDE FOR FROST THU MORNING IN
THE NORTH AS THE PATTERN DOES NOT LOOK FAVORABLE OR CONDUCIVE.
CONFIDENCE IN FROST POTENTIAL IS MUCH HIGHER ON SATURDAY MORNING
OVER THE NORTH-CNTRL ZONES WITH A LARGE AREA OF HIGH PRESSURE
FCST TO SETTLE OVER CENTRAL PA. MAINTAINED FROST WORDING IN SOME
NORTHERN ZONES. DRY WX SHOULD HOLD ON UNTIL EARLY NEXT WEEK AS
THE UPPER RIDGE BUILDS AGAIN OVER THE ERN U.S.
AN E-W FRONTAL BOUNDARY LOOKS TO BECOME A FOCUS FOR PCPN MON-TUE
AS IT PIVOTS AND LIFTS NWD IN A SIMILAR FASHION TO THIS PAST
WEEKEND. ALL GUIDANCE POINTS TO A GRADUAL WARMING TREND OVER THE
WEEKEND...WITH EVEN MILDER AND MORE MUGGY CONDITIONS STARTING
MEMORIAL DAY AND CONTINUING INTO NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
11 PM UPDATE...
A SHIELD OF MVFR CEILINGS HAS MOVED INTO THE LAURELS UP INTO THE NW
MOUNTAINS...AND WILL KEEP CEILINGS IN THE 1500-4000` RANGE IN
PLACE FOR MUCH OF THE OVERNIGHT. CEILINGS OF 3000-5000` MAY MAKE
IT DOWN INTO THE AREA FROM ALTOONA TO STATE COLLEGE AND
WILLIAMSPORT BUT DOWNSLOPE FLOW INTO THE LOWER SUSQ VALLEY SHOULD
FAVOR MAINLY SCATTERED SKIES.
LOW CEILINGS WILL MIX OUT AND LIFT QUICKLY WEDNESDAY MORNING
LEAVING VFR CONDITIONS AT ALL SITES BY MID DAY.
A GUSTY WIND WILL CONTINUE IN THE NEIGHBORHOOD OF 10-15 KT
OVERNIGHT BEFORE INCREASING ONCE AGAIN WED TO 15-25 KT.
OUTLOOK...
THU-FRI...NO SIG WX.
SUN...MAINLY VFR...MVFR POSS IN SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...RXR/STEINBUGL
AVIATION...LA CORTE
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1131 AM MDT WED MAY 20 2015
.UPDATE...
ISSUED AT 909 AM MDT WED MAY 20 2015
UPPER HIGH IS PUSHING DRIER AIR INTO THE NORTHERN PLAINS. SKIES
ARE BECOMING CLEAR FROM NORTH TO SOUTH...AND PRECIP IS
DIMINISHING. SURFACE HIGH PRESSURE IS DRAPED ACROSS THE CWA.
WINDS ARE LIGHT AND VARIABLE WITH TEMPS RISING INTO THE 40S AND
LOWER 50S. ADJUSTED SKY GRIDS AND POPS TO MATCH CURRENT
TRENDS...BUT REST OF FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR GUIDANCE
ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A PLEASANT
DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY
ISSUED AT 1126 AM MDT WED MAY 20 2015
VFR CONDITIONS WILL PERSIST ACROSS NORTHWESTERN SOUTH DAKOTA. A
FEW LIGHT SHOWERS WILL CONTINUE THROUGH THE AFTERNOON AROUND THE
BLACK HILLS...CREATING ISOLD MVFR CIGS. OTHERWISE CONDITIONS WILL
IMPROVE TO VFR FROM NORTH TO SOUTH THROUGH THE REST OF THE
AFTERNOON.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...POJORLIE
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...MLS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
914 AM MDT WED MAY 20 2015
.UPDATE...
ISSUED AT 909 AM MDT WED MAY 20 2015
UPPER HIGH IS PUSHING DRIER AIR INTO THE NORTHERN PLAINS. SKIES
ARE BECOMING CLEAR FROM NORTH TO SOUTH...AND PRECIP IS
DIMINISHING. SURFACE HIGH PRESSURE IS DRAPED ACROSS THE CWA.
WINDS ARE LIGHT AND VARIABLE WITH TEMPS RISING INTO THE 40S AND
LOWER 50S. ADJUSTED SKY GRIDS AND POPS TO MATCH CURRENT
TRENDS...BUT REST OF FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR GUIDANCE
ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A PLEASANT
DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING
ISSUED AT 535 AM MDT WED MAY 20 2015
LOW PRESSURE ALOFT WILL WEAKEN AND SHIFT EAST OF THE REGION
TODAY. AREAS OF LIGHT RAIN/SNOW WITH MVFR/IFR CONDITIONS OVER
SOUTHERN SD AND FAR NORTHEAST WY WILL CONTINUE EARLY THIS
MORNING...WITH PCPN TAPERING OFF AND CONDITIONS IMPROVING TO VFR
FROM NORTH TO SOUTH THROUGH THE REST OF THE MORNING AND MIDDAY
HOURS. VFR CONDITIONS WILL PERSIST ACROSS NORTHWEST SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...POJORLIE
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
536 AM MDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOUR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR
GUIDANCE ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A
PLEASANT DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING
ISSUED AT 535 AM MDT WED MAY 20 2015
LOW PRESSURE ALOFT WILL WEAKEN AND SHIFT EAST OF THE REGION
TODAY. AREAS OF LIGHT RAIN/SNOW WITH MVFR/IFR CONDITIONS OVER
SOUTHERN SD AND FAR NORTHEAST WY WILL CONTINUE EARLY THIS
MORNING...WITH PCPN TAPERING OFF AND CONDITIONS IMPROVING TO VFR
FROM NORTH TO SOUTH THROUGH THE REST OF THE MORNING AND MIDDAY
HOURS. VFR CONDITIONS WILL PERSIST ACROSS NORTHWEST SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
252 AM MDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOUR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR
GUIDANCE ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A
PLEASANT DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
LOW PRESSURE ALOFT WILL WEAKEN AND SHIFT EAST OF THE REGION THIS
MORNING. LIGHT RAIN/SNOW WITH MVFR/IFR CONDITIONS OVER SOUTHERN SD
AND PORTIONS OF NORTHEAST WY WILL CONTINUE EARLY THIS
MORNING...WITH PCPN TAPERING OFF AND CONDITIONS IMPROVING TO VFR
FROM NORTH TO SOUTH THROUGH THE REST OF THE MORNING AND MIDDAY
HOURS. VFR CONDITIONS WILL PERSIST ACROSS NORTHWEST SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1050 PM CDT THU MAY 21 2015
.AVIATION...
06Z TAF CYCLE
A STALLED FRONTAL BOUNDARY WILL LIFT NORTH AND EAST TOWARDS THE
PANHANDLES BY FRIDAY NIGHT. SCATTERED CONVECTION TONIGHT WILL MOVE
OFF TO THE EAST OF THE THREE TAF SITES BY 18Z FRIDAY. LIFR TO MVFR
CONDITIONS IN THE LOW CLOUDS...FOG AND CONVECTION TONIGHT AND FRIDAY
MORNING WILL BECOME MVFR AFTER 18Z AT ALL THREE TAF SITES. SOUTHEAST
WINDS 5 TO 15 KNOTS WILL BECOME SOUTHERLY 10 TO 20 KNOTS BY 15Z
FRIDAY...AND THEN INCREASE TO AROUND 15 TO 25 KNOTS WITH HIGHER GUSTS
AFTER 18Z FRIDAY. THE SOUTHERLY WINDS WILL THEN DIMINISH TO 10 TO 20
KNOTS AFTER 00Z SATURDAY.
SCHNEIDER
&&
.PREV DISCUSSION... /ISSUED 623 PM CDT THU MAY 21 2015/
AVIATION...
00Z TAF CYCLE
A STALLED FRONTAL BOUNDARY SOUTH OF THE PANHANDLES WILL MOVE BACK TO
THE NORTH AND EAST BY FRIDAY NIGHT AND APPROACH THE THREE TAF SITES.
INCREASING CONVECTION MAINLY TONIGHT INTO FRIDAY MORNING...AND AGAIN
FRIDAY NIGHT INTO SATURDAY MORNING CAN BE EXPECTED AT ALL THREE TAF
SITES. MVFR CONDITIONS WILL BECOME IFR TO LIFR AFTER 08Z TO 10Z
FRIDAY...AND THEN BACK TO MVFR AGAIN AFTER 18Z TO 20Z FRIDAY. WILL
KEEP SHOWERS AND OR THUNDERSTORMS IN ALL THREE TAF SITES THROUGH 15Z
TO 19Z FRIDAY. SOUTHEAST W2INDS 5 TO 15 KNOTS WILL BECOME SOUTH 10 TO
20 KNOTS AFTER 08Z TO 12Z FRIDAY...AND THE SOUTHERLY 15 TO 25 KNOTS
WITH HIGHER GUSTS AFTER 18Z TO 20Z FRIDAY.
SCHNEIDER
PREV DISCUSSION... /ISSUED 354 PM CDT THU MAY 21 2015/
SHORT TERM...
MUCH OF THE TEXAS PANHANDLE HAS SEEN NEARLY 48 HOURS OF OVERCAST SKY
CONDITIONS IN THE WAKE OF A COLD FRONT THAT PASSED THROUGH TUESDAY
EVENING. DESPITE THE DIFFERENTIAL ADVECTION PROFILE SEEN IN THE
12Z SOUNDING...MOISTURE WAS QUITE DEEP EVEN EXTENDING ABOVE THE
EAST-NORTHEASTERLY LOW LEVEL FLOW TO NEAR 700 MB WHERE FLOW WAS MORE
SOUTHWESTERLY. VISIBLE SATELLITE SHOWS SOME BREAKS IN THE NORTHEAST
TEXAS PANHANDLE AND THE EASTERN OKLAHOMA PANHANDLE THIS AFTERNOON
AND THIS HAS BEEN COINCIDENT WITH WARMER TEMPERATURES IN THE LOWER
60S. FURTHER WEST TEMPERATURES HAVE YET TO RISE OUT OF THE 50S AND
SO A SHORT TERM UPDATE WAS SENT TO LOWER TEMPERATURES SLIGHTLY. OUR
RECORD LOW MAX TEMPERATURE FOR TODAY IS 56 SET IN 1900. BASED ON
CURRENT TRENDS IN THE OBSERVATIONS AND EXAMINING THE DIURNAL CURVE
FROM YESTERDAY UNDER SIMILAR CONDITIONS...WE SHOULD REACH OR
SLIGHTLY EXCEED THIS TEMPERATURE THIS AFTERNOON.
SHORT RANGE GUIDANCE AGREES ON TIMING OF ONSET OF DEEPER SATURATION
SEEN ON ISENTROPIC SURFACES. THIS IS CAUSING SOME CONVECTION IN
EASTERN NEW MEXICO EXTENDING EAST TO JUST ACROSS THE TEXAS STATE
LINE...NEAR BOVINA. THIS ACTIVITY SHOULD CONTINUE MOVING
NORTHEASTWARD THIS AFTERNOON WHILE EXPANDING AS ASCENT FROM
APPROACHING LEAD WAVE STRENGTHENS. GIVEN THE SHORT RANGE MODEL
AGREEMENT ON THE LARGE SCALE BELIEVE THIS IS A FAIRLY GOOD CASE FOR
SUCCESS OF CONVECTION ALLOWING MODELS WITH TIMING AND COVERAGE OF
PRECIPITATION THIS EVENING AND INTO THE NIGHT. HOURLY PROBABILITY OF
PRECIPITATION GRIDS FOLLOW THESE MODELS INCLUDING THE HRRR AND
TTU-WRF FAIRLY CLOSELY. MOST OF THE PRECIPITATION SHOULD EXIT THE
AREA EARLY TOMORROW MORNING. SUBSIDENCE/MID LEVEL HEIGHT RISES IN
THE WAKE OF THE LEAD SHORTWAVE AND PRECEDING THE CLOSED UPPER LOW
SHOULD LIMIT OPPORTUNITY FOR CONVECTION TOMORROW AFTERNOON. HAVE
SIGNIFICANT REDUCED PRECIPITATION PROBABILITIES FOR TOMORROW
AFTERNOON. MODEL FORECAST SOUNDINGS REVEAL DIFFERENCES IN MODELS
WITH HOW MOIST THE LOW LEVELS ARE AND THIS HAS IMPLICATIONS FOR BOTH
CLOUD COVER AND TEMPERATURES. THE NAM HAS GENERALLY PERFORMED WELL
THE DAY FOLLOWING A NIGHTTIME CONVECTIVE EVENT RECENTLY SO GAVE IT
SOME CREDIT BUT TOOK A BLENDED APPROACH BETWEEN THE DRIER/WARMER NAM
AND THE MOIST/COOL GFS AND ECMWF. QPF GRIDS WERE ADJUSTED SLIGHTLY
AND DEVIATE ONLY SLIGHTLY FROM WPC GUIDANCE...MAINLY IN JUST A
TEMPORAL SENSE BUT WITH SLIGHTLY HIGHER AMOUNTS. TOTALS THROUGH
TOMORROW RANGE FROM AROUND A HALF INCH IN THE NORTHWEST TO NEAR AN
INCH IN THE SOUTHEAST.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
SPLIT FLOW UPPER AIR PATTERN WILL MAINTAIN A WET AND ACTIVE WEATHER
PATTERN FOR THE EXTENDED PERIOD AS A SERIES OF UPPER LEVEL
DISTURBANCES PASS ACROSS THE SOUTHERN PLAINS.
A PACIFIC UPPER LOW WILL MOVE ACROSS THE GREAT BASIN AREA FRIDAY
EVENING...WITH A LEAD SHORTWAVE EJECTING OUT OF THIS SYSTEM BEFORE
MOVING OVER THE REGION LATE FRIDAY NIGHT. LOW-LEVEL MOISTURE WILL
REMAIN PLENTIFUL COURTESY OF PERSISTENT SOUTHEAST UPSLOPE SURFACE FLOW
AND A LIFTING WARM FRONT. WITH THE DRYLINE REMAINING IN EASTERN NM
LARGE SCALE ASCENT WILL BE THE PRIMARY FOCUS FOR CONVECTION
INITIATION FRIDAY EVENING...WITH THE HIGHEST CHANCES FOR PRECIP
OCCURRING BETWEEN 06-12Z SATURDAY. HIGH PW VALUES...NEAR THE 99TH
PERCENTILE...WILL SUPPORT MODERATE TO HEAVY RAINFALL. THIS IN TURN
RAISES CONCERN FOR THE FLOODING POTENTIAL PARTICULARLY OVER THE
SOUTHEAST TEXAS PANHANDLE WHERE RAINFALL TOTALS OVER 2 INCHES
OCCURRED OVER THE PAST 3 DAYS AND SOILS ARE MORE CONDUCIVE TO
FLOODING. DID CONTEMPLATE EXPANDING THE CURRENT FLASH FLOOD WATCH
FURTHER WESTWARD GIVEN ALL THE RAIN THE SOUTHERN TEXAS PANHANDLE HAS
RECEIVED RECENTLY. DECIDED TO HOLD OFF ON EXPANDING THE WATCH AS
CONFIDENCE IS NOT HIGH ENOUGH THAT ENOUGH RAINFALL WILL RESULT IN
FLASH FLOODING.
THE UPPER LOW WILL MOVE INTO THE FOUR CORNERS REGION SATURDAY EVENING
AND LIFT SLOWLY TO THE NORTHEAST SUNDAY. SEVERAL UPPER LEVEL
SHORTWAVE TROUGHS WILL MAINTAIN A THREAT OF SHOWERS AND THUNDERSTORMS
THROUGH THE HOLIDAY WEEKEND. THE DRYLINE WILL MIX A BIT FURTHER
EASTWARD SUNDAY...WHICH WILL FOCUS STORM INITIATION GENERALLY OVER
THE EASTERN PANHANDLES. IN GENERAL NOT EXPECTING MUCH IN THE WAY OF
SEVERE WEATHER ALTHOUGH POSSIBLE IF THERE IS ENOUGH DAYTIME
DESTABILIZATION...SOME STRONG TO SEVERE STORMS WILL BE POSSIBLE.
MAY SEE A BRIEF BREAK IN THE RAIN EARLY NEXT WEEK ALTHOUGH WITH THE
MEDIUM RANGE MODELS IN DISAGREEMENT IN THE SPEED OF THE UPPER
TROUGH...HELD ONTO SLIGHT CHANCE POPS MEMORIAL DAY. DECENT LOW-LEVEL
MOISTURE IN PLACE AND ANOTHER UPPER DISTURBANCE MOVING THROUGH THE
FOUR CORNERS REGION CAN GENERATE MORE SHOWERS AND THUNDERSTORMS
MIDWEEK.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH FROM LATE FRIDAY NIGHT THROUGH LATE SATURDAY
NIGHT FOR THE FOLLOWING ZONES: ARMSTRONG...COLLINGSWORTH...
DONLEY...GRAY...WHEELER.
OK...NONE.
&&
$$
11/99
AREA FORECAST DISCUSSION
NWS AMARILLO TX
623 PM CDT THU MAY 21 2015
.AVIATION...
00Z TAF CYCLE
A STALLED FRONTAL BOUNDARY SOUTH OF THE PANHANDLES WILL MOVE BACK TO
THE NORTH AND EAST BY FRIDAY NIGHT AND APPROACH THE THREE TAF SITES.
INCREASING CONVECTION MAINLY TONIGHT INTO FRIDAY MORNING...AND AGAIN
FRIDAY NIGHT INTO SATURDAY MORNING CAN BE EXPECTED AT ALL THREE TAF
SITES. MVFR CONDITIONS WILL BECOME IFR TO LIFR AFTER 08Z TO 10Z
FRIDAY...AND THEN BACK TO MVFR AGAIN AFTER 18Z TO 20Z FRIDAY. WILL
KEEP SHOWERS AND OR THUNDERSTORMS IN ALL THREE TAF SITES THROUGH 15Z
TO 19Z FRIDAY. SOUTHEAST W2INDS 5 TO 15 KNOTS WILL BECOME SOUTH 10 TO
20 KNOTS AFTER 08Z TO 12Z FRIDAY...AND THE SOUTHERLY 15 TO 25 KNOTS
WITH HIGHER GUSTS AFTER 18Z TO 20Z FRIDAY.
SCHNEIDER
&&
.PREV DISCUSSION... /ISSUED 354 PM CDT THU MAY 21 2015/
SHORT TERM...
MUCH OF THE TEXAS PANHANDLE HAS SEEN NEARLY 48 HOURS OF OVERCAST SKY
CONDITIONS IN THE WAKE OF A COLD FRONT THAT PASSED THROUGH TUESDAY
EVENING. DESPITE THE DIFFERENTIAL ADVECTION PROFILE SEEN IN THE
12Z SOUNDING...MOISTURE WAS QUITE DEEP EVEN EXTENDING ABOVE THE
EAST-NORTHEASTERLY LOW LEVEL FLOW TO NEAR 700 MB WHERE FLOW WAS MORE
SOUTHWESTERLY. VISIBLE SATELLITE SHOWS SOME BREAKS IN THE NORTHEAST
TEXAS PANHANDLE AND THE EASTERN OKLAHOMA PANHANDLE THIS AFTERNOON
AND THIS HAS BEEN COINCIDENT WITH WARMER TEMPERATURES IN THE LOWER
60S. FURTHER WEST TEMPERATURES HAVE YET TO RISE OUT OF THE 50S AND
SO A SHORT TERM UPDATE WAS SENT TO LOWER TEMPERATURES SLIGHTLY. OUR
RECORD LOW MAX TEMPERATURE FOR TODAY IS 56 SET IN 1900. BASED ON
CURRENT TRENDS IN THE OBSERVATIONS AND EXAMINING THE DIURNAL CURVE
FROM YESTERDAY UNDER SIMILAR CONDITIONS...WE SHOULD REACH OR
SLIGHTLY EXCEED THIS TEMPERATURE THIS AFTERNOON.
SHORT RANGE GUIDANCE AGREES ON TIMING OF ONSET OF DEEPER SATURATION
SEEN ON ISENTROPIC SURFACES. THIS IS CAUSING SOME CONVECTION IN
EASTERN NEW MEXICO EXTENDING EAST TO JUST ACROSS THE TEXAS STATE
LINE...NEAR BOVINA. THIS ACTIVITY SHOULD CONTINUE MOVING
NORTHEASTWARD THIS AFTERNOON WHILE EXPANDING AS ASCENT FROM
APPROACHING LEAD WAVE STRENGTHENS. GIVEN THE SHORT RANGE MODEL
AGREEMENT ON THE LARGE SCALE BELIEVE THIS IS A FAIRLY GOOD CASE FOR
SUCCESS OF CONVECTION ALLOWING MODELS WITH TIMING AND COVERAGE OF
PRECIPITATION THIS EVENING AND INTO THE NIGHT. HOURLY PROBABILITY OF
PRECIPITATION GRIDS FOLLOW THESE MODELS INCLUDING THE HRRR AND
TTU-WRF FAIRLY CLOSELY. MOST OF THE PRECIPITATION SHOULD EXIT THE
AREA EARLY TOMORROW MORNING. SUBSIDENCE/MID LEVEL HEIGHT RISES IN
THE WAKE OF THE LEAD SHORTWAVE AND PRECEDING THE CLOSED UPPER LOW
SHOULD LIMIT OPPORTUNITY FOR CONVECTION TOMORROW AFTERNOON. HAVE
SIGNIFICANT REDUCED PRECIPITATION PROBABILITIES FOR TOMORROW
AFTERNOON. MODEL FORECAST SOUNDINGS REVEAL DIFFERENCES IN MODELS
WITH HOW MOIST THE LOW LEVELS ARE AND THIS HAS IMPLICATIONS FOR BOTH
CLOUD COVER AND TEMPERATURES. THE NAM HAS GENERALLY PERFORMED WELL
THE DAY FOLLOWING A NIGHTTIME CONVECTIVE EVENT RECENTLY SO GAVE IT
SOME CREDIT BUT TOOK A BLENDED APPROACH BETWEEN THE DRIER/WARMER NAM
AND THE MOIST/COOL GFS AND ECMWF. QPF GRIDS WERE ADJUSTED SLIGHTLY
AND DEVIATE ONLY SLIGHTLY FROM WPC GUIDANCE...MAINLY IN JUST A
TEMPORAL SENSE BUT WITH SLIGHTLY HIGHER AMOUNTS. TOTALS THROUGH
TOMORROW RANGE FROM AROUND A HALF INCH IN THE NORTHWEST TO NEAR AN
INCH IN THE SOUTHEAST.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
SPLIT FLOW UPPER AIR PATTERN WILL MAINTAIN A WET AND ACTIVE WEATHER
PATTERN FOR THE EXTENDED PERIOD AS A SERIES OF UPPER LEVEL
DISTURBANCES PASS ACROSS THE SOUTHERN PLAINS.
A PACIFIC UPPER LOW WILL MOVE ACROSS THE GREAT BASIN AREA FRIDAY
EVENING...WITH A LEAD SHORTWAVE EJECTING OUT OF THIS SYSTEM BEFORE
MOVING OVER THE REGION LATE FRIDAY NIGHT. LOW-LEVEL MOISTURE WILL
REMAIN PLENTIFUL COURTESY OF PERSISTENT SOUTHEAST UPSLOPE SURFACE FLOW
AND A LIFTING WARM FRONT. WITH THE DRYLINE REMAINING IN EASTERN NM
LARGE SCALE ASCENT WILL BE THE PRIMARY FOCUS FOR CONVECTION
INITIATION FRIDAY EVENING...WITH THE HIGHEST CHANCES FOR PRECIP
OCCURRING BETWEEN 06-12Z SATURDAY. HIGH PW VALUES...NEAR THE 99TH
PERCENTILE...WILL SUPPORT MODERATE TO HEAVY RAINFALL. THIS IN TURN
RAISES CONCERN FOR THE FLOODING POTENTIAL PARTICULARLY OVER THE
SOUTHEAST TEXAS PANHANDLE WHERE RAINFALL TOTALS OVER 2 INCHES
OCCURRED OVER THE PAST 3 DAYS AND SOILS ARE MORE CONDUCIVE TO
FLOODING. DID CONTEMPLATE EXPANDING THE CURRENT FLASH FLOOD WATCH
FURTHER WESTWARD GIVEN ALL THE RAIN THE SOUTHERN TEXAS PANHANDLE HAS
RECEIVED RECENTLY. DECIDED TO HOLD OFF ON EXPANDING THE WATCH AS
CONFIDENCE IS NOT HIGH ENOUGH THAT ENOUGH RAINFALL WILL RESULT IN
FLASH FLOODING.
THE UPPER LOW WILL MOVE INTO THE FOUR CORNERS REGION SATURDAY EVENING
AND LIFT SLOWLY TO THE NORTHEAST SUNDAY. SEVERAL UPPER LEVEL
SHORTWAVE TROUGHS WILL MAINTAIN A THREAT OF SHOWERS AND THUNDERSTORMS
THROUGH THE HOLIDAY WEEKEND. THE DRYLINE WILL MIX A BIT FURTHER
EASTWARD SUNDAY...WHICH WILL FOCUS STORM INITIATION GENERALLY OVER
THE EASTERN PANHANDLES. IN GENERAL NOT EXPECTING MUCH IN THE WAY OF
SEVERE WEATHER ALTHOUGH POSSIBLE IF THERE IS ENOUGH DAYTIME
DESTABILIZATION...SOME STRONG TO SEVERE STORMS WILL BE POSSIBLE.
MAY SEE A BRIEF BREAK IN THE RAIN EARLY NEXT WEEK ALTHOUGH WITH THE
MEDIUM RANGE MODELS IN DISAGREEMENT IN THE SPEED OF THE UPPER
TROUGH...HELD ONTO SLIGHT CHANCE POPS MEMORIAL DAY. DECENT LOW-LEVEL
MOISTURE IN PLACE AND ANOTHER UPPER DISTURBANCE MOVING THROUGH THE
FOUR CORNERS REGION CAN GENERATE MORE SHOWERS AND THUNDERSTORMS
MIDWEEK.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH FROM LATE FRIDAY NIGHT THROUGH LATE SATURDAY
NIGHT FOR THE FOLLOWING ZONES: ARMSTRONG...COLLINGSWORTH...
DONLEY...GRAY...WHEELER.
OK...NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
552 PM CDT Wed May 20 2015
.UPDATE...
Thunderstorms, some severe, will continue to develop along or near
the cold front this evening. The cold front now extends near a
line from Barnhart...to Eldorado...to Brady. After coordination
with the Storm Prediction Central...we have issued Severe
Thunderstorm Watch number 192, which is valid until midnight CDT
tonight, for counties along and south of a line from Mertzon to
Brady. The latest Zone package headlines this watch for the
appropriate counties.
&&
.PREV DISCUSSION... /ISSUED 350 PM CDT Wed May 20 2015/
SHORT TERM...
(Tonight and Thursday)
A rather strong cold front has moved south of a San Angelo to
Coleman line this afternoon, dropping temperatures into the upper
50s and lower 60s across the Big Country. Low clouds and cold
advection north of the front has greatly reduced instability,
limiting the potential for diurnal convection. Ahead of the front,
temperatures have warmed into the lower 80s with dewpoints hanging
in the mid/upper 60s. Modified RAP soundings indicate SBCAPE values
on the order of 2000-2500 J/kg in the warm sector with effective
shear values exceeding 35 kts. This will support organized
convection this afternoon and during the evening hours, with the
primary focus along and south of the front. The primary concern is
for large hail and damaging winds. However, a tornadic storm cannot
be ruled out in the vicinity of this boundary.
Right moving supercell vectors are from the west and northwest at 10
to 15 mph. This slow storm motion and the presence of the
aforementioned cold front will support the potential for locally
heavy rainfall along the I-10 corridor tonight. Additional storms
will be possible overnight as isentropic ascent develops over the
frontal zone. As the front moves south overnight and early Thursday,
rain chances are expected to diminish during the morning hours.
However, shortwave ridging aloft will be shifting to the east as a
strong shortwave trough moves across the southern Rockies.
Increasing large scale ascent will promote the development of
scattered showers and thunderstorms during the afternoon hours.
Fortunately, the severe weather potential is expected to remain low
on Thursday. Much cooler temperatures are anticipated tomorrow, with
highs in the 60s across most of the area.
Johnson
LONG TERM...
(Thursday night through next Wednesday)
The main focus is with the severe weather and heavy rainfall
possibility for the Memorial Day holiday weekend.
Increased chance and coverage of showers and thunderstorms
is expected across our area Thursday night, with the arrival
of a stronger shortwave in southwest flow aloft. With subsidence
and advection of some drier mid-level air in the wake of this
departing shortwave, will have reduced chances for showers and
thunderstorms on Friday.
An upper low will move northeast into southeastern Utah Friday
night, with an upper trough trailing from the low across the
Desert Southwest. The main chance for showers and thunderstorms
Friday night will be overnight, and across our northwestern
counties, with the possibility of a weak embedded disturbance
out ahead of the main trough lifting northeast into far west
or northwest Texas.
The aforementioned upper trough will move slowly east across
Arizona and New Mexico over the holiday weekend. Given the
forecast strength of this system, will have increased potential
for severe weather with stronger instability and increased
vertical shear. Carrying higher PoPs over the weekend with the
highest rain chance on Saturday night. Heavy rainfall will also
be possible with repeat convective activity and precipitable
water values at or above 1.5 inches across much of our area.
The upper trough is progged to eventually lift northeast across
Texas, but the 12Z GFS and ECMWF differ on the timing.
Following departure of this system, drier and warmer conditions
look to be in store for our area as heights build aloft. May
have another upper trough approach from the southwestern states
next Wednesday, but keeping PoPs below mention with the
uncertainty at this time.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 57 66 58 78 67 / 50 40 60 50 40
San Angelo 60 68 61 81 67 / 60 40 60 30 30
Junction 65 72 65 82 68 / 70 50 50 30 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
350 PM CDT Wed May 20 2015
.SHORT TERM...
(Tonight and Thursday)
A rather strong cold front has moved south of a San Angelo to
Coleman line this afternoon, dropping temperatures into the upper
50s and lower 60s across the Big Country. Low clouds and cold
advection north of the front has greatly reduced instability,
limiting the potential for diurnal convection. Ahead of the front,
temperatures have warmed into the lower 80s with dewpoints hanging
in the mid/upper 60s. Modified RAP soundings indicate SBCAPE values
on the order of 2000-2500 J/kg in the warm sector with effective
shear values exceeding 35 kts. This will support organized
convection this afternoon and during the evening hours, with the
primary focus along and south of the front. The primary concern is
for large hail and damaging winds. However, a tornadic storm cannot
be ruled out in the vicinity of this boundary.
Right moving supercell vectors are from the west and northwest at 10
to 15 mph. This slow storm motion and the presence of the
aforementioned cold front will support the potential for locally
heavy rainfall along the I-10 corridor tonight. Additional storms
will be possible overnight as isentropic ascent develops over the
frontal zone. As the front moves south overnight and early Thursday,
rain chances are expected to diminish during the morning hours.
However, shortwave ridging aloft will be shifting to the east as a
strong shortwave trough moves across the southern Rockies.
Increasing large scale ascent will promote the development of
scattered showers and thunderstorms during the afternoon hours.
Fortunately, the severe weather potential is expected to remain low
on Thursday. Much cooler temperatures are anticipated tomorrow, with
highs in the 60s across most of the area.
Johnson
.LONG TERM...
(Thursday night through next Wednesday)
The main focus is with the severe weather and heavy rainfall
possibility for the Memorial Day holiday weekend.
Increased chance and coverage of showers and thunderstorms
is expected across our area Thursday night, with the arrival
of a stronger shortwave in southwest flow aloft. With subsidence
and advection of some drier mid-level air in the wake of this
departing shortwave, will have reduced chances for showers and
thunderstorms on Friday.
An upper low will move northeast into southeastern Utah Friday
night, with an upper trough trailing from the low across the
Desert Southwest. The main chance for showers and thunderstorms
Friday night will be overnight, and across our northwestern
counties, with the possibility of a weak embedded disturbance
out ahead of the main trough lifting northeast into far west
or northwest Texas.
The aforementioned upper trough will move slowly east across
Arizona and New Mexico over the holiday weekend. Given the
forecast strength of this system, will have increased potential
for severe weather with stronger instability and increased
vertical shear. Carrying higher PoPs over the weekend with the
highest rain chance on Saturday night. Heavy rainfall will also
be possible with repeat convective activity and precipitable
water values at or above 1.5 inches across much of our area.
The upper trough is progged to eventually lift northeast across
Texas, but the 12Z GFS and ECMWF differ on the timing.
Following departure of this system, drier and warmer conditions
look to be in store for our area as heights build aloft. May
have another upper trough approach from the southwestern states
next Wednesday, but keeping PoPs below mention with the
uncertainty at this time.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 57 66 58 78 67 / 50 40 60 50 40
San Angelo 60 68 61 81 67 / 60 40 60 30 30
Junction 65 72 65 82 68 / 70 50 50 30 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1244 PM CDT Wed May 20 2015
.AVIATION...
/18Z TAFS/
IFR to LIFR conditions are prevalent behind the cold front moving
south across the area this afternoon. This will result ceilings
below 700 ft at both KABI and KSWW. This front should reach KSJT
by mid-afternoon, resulting in similar conditions after 20z.
Scattered, short-lived showers are developing across the area, but
are expected to become more organized this afternoon as
temperatures along the I-10 corridor approach 80 degrees.
Thunderstorms are expected south of a KSJT to KBBD line this
afternoon and evening, and could persist well into the overnight
hours as the boundary stalls across the southern portion of the
CWA. Expect southeast/east winds to shift to the north and
northeast behind this cold front.
Johnson
&&
.PREV DISCUSSION... /ISSUED 950 AM CDT Wed May 20 2015/
UPDATE...
A cold front is moving slowly south across the Big Country this
morning, currently extending from just near Big Spring, to just
north of Abilene, to Jacksboro. A few showers have developed along
and north of this boundary, but should remain relatively light and
unorganized. Temperatures have dropped into the upper 50s and
lower 60s in areas north of I-20, with dewpoints as low as the
50s. An outflow boundary from overnight convection has moved south
to near a Brownwood to San Angelo line and continues to sag slowly
toward I-10. Precipitation amounts should remain rather light
through early afternoon, but as the boundary layer destabilizes,
scattered convection is expected to develop.
The most likely area for convective initiation is roughly south of
a San Angelo to Brownwood line (where the cold front is forecast
to be near peak heating). If we get enough breaks in the cloud
cover, instability and vertical shear should be sufficient to
support strong to severe thunderstorms. This would present a
potential for localized heavy rainfall, but coverage is expected
to be limited, so not Flash Flood Watch will be issued.
Temperatures were lowered a few degrees across the Big Country
this afternoon, but otherwise minimal changes were made to the
inherited forecast.
PREV DISCUSSION... /ISSUED 650 AM CDT Wed May 20 2015/
AVIATION...
/12Z TAFS/
Widespread stratus is expected across West Central Texas this
morning, with MVFR/IFR ceilings. The ceilings will lift to low end
VFR across much of the area this afternoon and continue this
evening, besides the KABI terminal remaining MVFR. Scattered
thunderstorms should develop this afternoon and evening across the
mainly the southern 2/3 of the area and have VCTS at most of the
terminals. A few storms may be severe.
PREV DISCUSSION... /ISSUED 450 AM CDT Wed May 20 2015/
SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A
few storms may be severe during the evening. The cool front
should move south of the area after midnight and convection should
begin to weaken some.
LONG TERM...
(Thursday through Tuesday)
Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aforementioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
950 AM CDT Wed May 20 2015
.UPDATE...
A cold front is moving slowly south across the Big Country this
morning, currently extending from just near Big Spring, to just
north of Abilene, to Jacksboro. A few showers have developed along
and north of this boundary, but should remain relatively light and
unorganized. Temperatures have dropped into the upper 50s and
lower 60s in areas north of I-20, with dewpoints as low as the
50s. An outflow boundary from overnight convection has moved south
to near a Brownwood to San Angelo line and continues to sag slowly
toward I-10. Precipitation amounts should remain rather light
through early afternoon, but as the boundary layer destabilizes,
scattered convection is expected to develop.
The most likely area for convective initiation is roughly south of
a San Angelo to Brownwood line (where the cold front is forecast
to be near peak heating). If we get enough breaks in the cloud
cover, instability and vertical shear should be sufficient to
support strong to severe thunderstorms. This would present a
potential for localized heavy rainfall, but coverage is expected
to be limited, so not Flash Flood Watch will be issued.
Temperatures were lowered a few degrees across the Big Country
this afternoon, but otherwise minimal changes were made to the
inherited forecast.
Johnson
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT Wed May 20 2015/
AVIATION...
/12Z TAFS/
Widespread stratus is expected across West Central Texas this
morning, with MVFR/IFR ceilings. The ceilings will lift to low end
VFR across much of the area this afternoon and continue this
evening, besides the KABI terminal remaining MVFR. Scattered
thunderstorms should develop this afternoon and evening across the
mainly the southern 2/3 of the area and have VCTS at most of the
terminals. A few storms may be severe.
PREV DISCUSSION... /ISSUED 450 AM CDT Wed May 20 2015/
SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A
few storms may be severe during the evening. The cool front
should move south of the area after midnight and convection should
begin to weaken some.
LONG TERM...
(Thursday through Tuesday)
.Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aforementioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
650 AM CDT Wed May 20 2015
.AVIATION...
/12Z TAFS/
Widespread stratus is expected across West Central Texas this
morning, with MVFR/IFR ceilings. The ceilings will lift to low end
VFR across much of the area this afternoon and continue this
evening, besides the KABI terminal remaining MVFR. Scattered
thunderstorms should develop this afternoon and evening across the
mainly the southern 2/3 of the area and have VCTS at most of the
terminals. A few storms may be severe.
&&
.PREV DISCUSSION... /ISSUED 450 AM CDT Wed May 20 2015/
SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A few
storms may be severe during the evening. The cool front should move
south of the area after midnight and convection should begin to
weaken some.
LONG TERM...
(Thursday through Tuesday)
..Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aformentioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
626 AM CDT WED MAY 20 2015
.DISCUSSION...12Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...MVFR STRATUS PREVAILS ACROSS MOST OF SOUTH-CENTRAL
TEXAS EARLY THIS MORNING...WITH SOME ISOLATED SPOTS IN IFR RANGE.
CEILINGS IMPROVING BACK TO VFR 18Z-21Z. ISOLATED SHRAS AND TSTMS
POSSIBLE DURING THE AFTERNOON ACROSS NORTHERN AND EASTERN
AREAS...INCLUDING VICINITY OF AUS. A COLD FRONT WILL APPROACH THE
HILL COUNTRY DURING THE LATE AFTERNOON...WITH SCATTERED SHRAS AND
TSTMS ALONG IT. TREND AMONG HI RESOLUTION MODELS HAS BEEN QUICKER
WITH THE SOUTHWARD PROGRESSION OF THE FRONT THROUGH THE DAY...
ALTHOUGH CONVECTIVE OUTFLOW BOUNDARIES WILL ULTIMATELY PLAY A KEY
ROLE IN EXACTLY HOW FAST THE FRONT MOVES SOUTH AND EXACT TIMING
INTO THE CWA. HAVE MOVED THE TIMING OF TSTMS UP IN THE 12Z AUS
AND DRT TAFS...WITH TSTMS MENTIONED AS EARLY AS 00Z NOW. THE
TIMING WILL LIKELY BE REFINED FURTHER IN THE 18Z TAFS AS TRENDS
BECOME BETTER ESTABLISHED. CONDITIONS WILL BE FAVORABLE FOR A FEW
STORMS TO BECOME STRONG TO SEVERE ALONG AND NORTH OF AN AUS TO UVA
LINE.
&&
.PREV DISCUSSION... /ISSUED 426 AM CDT WED MAY 20 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...
AREA STREAMS AND RIVERS ARE HAVING A BRIEF PERIOD TO RECOVER
THROUGH EARLY TODAY BEFORE A COLD FRONT ARRIVES TO TRIGGER NEW
CONVECTION AND POSSIBLY RIVER RISES. MOST OF THE HIGHER RES MODELS
GENERATE WHAT LOOKS TO BE STRONG TO SEVERE STORMS OVER THE WESTERN
HALF OF THE FORECAST AREA WHERE THE COLD FRONT INTERACTS WITH HIGH
EVENING CAPE VALUES AND LIGHT TO MODERATE SHEAR. WITH SPC MESO-
ANALYSIS SHOWING HIGH PWAT VALUES OVER THE COMPLEX RIDING ALONG
THE COLD FRONT OVER THE RED RIVER VALLEY EARLY THIS MORNING...WILL
EXPECT A SIMILAR ENVIRONMENT SETTING UP FOR CENTRAL TX INTO THE
WESTERN HILL COUNTRY THIS EVENING. THE PAST COUPLE RUNS OF THE NAM
MODEL SEEM TO REFLECT A GOOD MIDDLE GROUND FROM THE HIGH RES CAMPS
THAT SHOW EXTRA EMPHASIS OVER WESTERN COUNTIES AND OTHERS...
INCLUDING RECENT HRRR RUNS...THAT KEEP THE CURRENT COMPLEX ALIVE
AND MOVE IT INTO MAINLY CENTRAL AND EASTERN COUNTIES IN THE LATE
AFTERNOON HOURS.
IN THE FIRST OPERATIONAL PERIOD FOR TODAY...WILL FOLLOW A PORTION
OF THE EASTERN SOLUTIONS OF HIGHER RES RUNS WITH THE EXPECTATION
THAT SOME GRAVITY WAVE INDUCED SHOWER ACTIVITY TAPS INTO LOCALLY
HIGHER PWAT VALUES. SLIGHTLY HIGHER POPS ARE SHOWN OVER CENTRAL
TX FOR THIS AFTERNOON. HOWEVER...EXPECT THE SURFACE FRONTAL
BOUNDARY TO MIX OUT...AND MID LEVEL STABILITY TO HOLD BACK MOST
DEEP CONVECTION. WILL NEED TO MONITOR THE CONVECTIVE DEVELOPMENT
CLOSELY OVER CENTRAL TX SHOULD THE CONVECTIVE OUTFLOW BE MORE
ROBUST OVER NORTH TX IN THE LATE MORNING HOURS.
BY THIS EVENING...THE NAM COMPROMISE SOLUTION SHOWS ITS HIGHEST
IMPACT OVER THE NORTHERN HILL COUNTRY AND COULD MEAN A THREAT FOR
BOTH SEVERE WEATHER AND FLASH FLOODING WITH SLOW SOUTHWARD
PROPAGATING CELLS MOVING DOWN HIGHWAY 281. WHILE THIS SIGNAL WAS
SIMILAR IN TWO STRAIGHT NAM RUNS...LOWER RES SOLUTIONS SHOW
HIGHEST RAIN POTENTIAL MUCH FARTHER TO THE WEST WITH FRONTAL
FORCING LIMITED OVER EASTERN COUNTIES. THUS WILL BALK AT ISSUING
AN FFA...AS FLOODING THREATS SHOULD BE SOMEWHAT ISOLATED SHOULD
THE WESTERN SOLUTIONS PREVAIL. TOWARD DAYBREAK...MUCH OF THE AREA
SHOULD SHOW SOME LOW LEVEL STABILITY FROM THE FRONT...WITH MOST OF
THE ELEVATED RAINS EXPECTED TO BE LIGHT TO MODERATE INTO THURSDAY.
THE FRONT IS EXPECTED TO BE WEAK AND SHALLOW...SO WILL SHOW CHANCE
CATEGORY POPS WHICH SIDE WITH THE LOWER RES MODELS OVER THE DRIER
SOLUTIONS OF MOST HIGHER RES RUNS.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
ASSUMING WE GET THROUGH TONIGHTS SITUATIONAL HEAVY RAIN THREAT
WITHOUT A MAJOR ORDEAL...THE HEAVY RAIN EMPHASIS WE ARE MOST
CONCERNED ABOUT IS OVER THE WEEKEND. A SHARPENING AND HIGH
AMPLITUDE UPPER TROUGH TO THE SOUTHWEST WILL INCREASE POPS
GRADUALLY FRIDAY INTO SATURDAY...AND THEN AGRESSIVELY SATURDAY
NIGHT THROUGH SUNDAY EVENING. A WIDESPREAD HEAVY RAIN OF 1 TO 3
INCHES IS EXPECTED FOR THIS ENHANCED PERIOD WITH ISOLATED HIGHER
AMOUNTS OF 4 TO 6 INCHES POSSIBLE. THE ECMWF AND CANADIAN EVEN
CARRY THE EVENT INTO MEMORIAL DAY...WHICH COULD SEND PROJECTIONS
EVEN HIGHER. FOR NOW...WILL ASSUME THAT A WIDESPREAD MCS OVER THE
WEEKEND SHOULD TEMPORARILY STABILIZE THE AIR FOR MONDAY WHICH
FAVORS THE MORE CONSERVATIVE GFS SOLUTION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 86 69 79 66 83 / 30 50 30 40 40
AUSTIN BERGSTROM INTL AIRPORT 85 68 79 66 83 / 30 50 30 40 40
NEW BRAUNFELS MUNI AIRPORT 86 70 81 67 83 / 30 40 40 40 40
BURNET MUNI AIRPORT 83 66 75 63 80 / 30 60 30 40 40
DEL RIO INTL AIRPORT 86 71 82 69 85 / 20 60 50 60 40
GEORGETOWN MUNI AIRPORT 84 66 76 64 82 / 30 60 30 40 40
HONDO MUNI AIRPORT 86 71 82 68 84 / 20 50 40 50 40
SAN MARCOS MUNI AIRPORT 85 69 79 66 82 / 30 40 30 40 40
LA GRANGE - FAYETTE REGIONAL 86 70 81 69 83 / 30 20 40 30 40
SAN ANTONIO INTL AIRPORT 86 71 81 69 83 / 20 40 40 40 40
STINSON MUNI AIRPORT 87 72 82 69 84 / 20 30 40 40 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...76
SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
450 AM CDT Wed May 20 2015
.SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A few
storms may be severe during the evening. The cool front should move
south of the area after midnight and convection should begin to
weaken some.
.LONG TERM...
(Thursday through Tuesday)
...Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aformentioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21/24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
426 AM CDT WED MAY 20 2015
.SHORT TERM (TODAY THROUGH THURSDAY)...
AREA STREAMS AND RIVERS ARE HAVING A BRIEF PERIOD TO RECOVER
THROUGH EARLY TODAY BEFORE A COLD FRONT ARRIVES TO TRIGGER NEW
CONVECTION AND POSSIBLY RIVER RISES. MOST OF THE HIGHER RES MODELS
GENERATE WHAT LOOKS TO BE STRONG TO SEVERE STORMS OVER THE WESTERN
HALF OF THE FORECAST AREA WHERE THE COLD FRONT INTERACTS WITH HIGH
EVENING CAPE VALUES AND LIGHT TO MODERATE SHEAR. WITH SPC MESO-
ANALYSIS SHOWING HIGH PWAT VALUES OVER THE COMPLEX RIDING ALONG
THE COLD FRONT OVER THE RED RIVER VALLEY EARLY THIS MORNING...WILL
EXPECT A SIMILAR ENVIRONMENT SETTING UP FOR CENTRAL TX INTO THE
WESTERN HILL COUNTRY THIS EVENING. THE PAST COUPLE RUNS OF THE NAM
MODEL SEEM TO REFLECT A GOOD MIDDLE GROUND FROM THE HIGH RES CAMPS
THAT SHOW EXTRA EMPHASIS OVER WESTERN COUNTIES AND OTHERS...
INCLUDING RECENT HRRR RUNS...THAT KEEP THE CURRENT COMPLEX ALIVE
AND MOVE IT INTO MAINLY CENTRAL AND EASTERN COUNTIES IN THE LATE
AFTERNOON HOURS.
IN THE FIRST OPERATIONAL PERIOD FOR TODAY...WILL FOLLOW A PORTION
OF THE EASTERN SOLUTIONS OF HIGHER RES RUNS WITH THE EXPECTATION
THAT SOME GRAVITY WAVE INDUCED SHOWER ACTIVITY TAPS INTO LOCALLY
HIGHER PWAT VALUES. SLIGHTLY HIGHER POPS ARE SHOWN OVER CENTRAL
TX FOR THIS AFTERNOON. HOWEVER...EXPECT THE SURFACE FRONTAL
BOUNDARY TO MIX OUT...AND MID LEVEL STABILITY TO HOLD BACK MOST
DEEP CONVECTION. WILL NEED TO MONITOR THE CONVECTIVE DEVELOPMENT
CLOSELY OVER CENTRAL TX SHOULD THE CONVECTIVE OUTFLOW BE MORE
ROBUST OVER NORTH TX IN THE LATE MORNING HOURS.
BY THIS EVENING...THE NAM COMPROMISE SOLUTION SHOWS ITS HIGHEST
IMPACT OVER THE NORTHERN HILL COUNTRY AND COULD MEAN A THREAT FOR
BOTH SEVERE WEATHER AND FLASH FLOODING WITH SLOW SOUTHWARD
PROPAGATING CELLS MOVING DOWN HIGHWAY 281. WHILE THIS SIGNAL WAS
SIMILAR IN TWO STRAIGHT NAM RUNS...LOWER RES SOLUTIONS SHOW
HIGHEST RAIN POTENTIAL MUCH FARTHER TO THE WEST WITH FRONTAL
FORCING LIMITED OVER EASTERN COUNTIES. THUS WILL BALK AT ISSUING
AN FFA...AS FLOODING THREATS SHOULD BE SOMEWHAT ISOLATED SHOULD
THE WESTERN SOLUTIONS PREVAIL. TOWARD DAYBREAK...MUCH OF THE AREA
SHOULD SHOW SOME LOW LEVEL STABILITY FROM THE FRONT...WITH MOST OF
THE ELEVATED RAINS EXPECTED TO BE LIGHT TO MODERATE INTO THURSDAY.
THE FRONT IS EXPECTED TO BE WEAK AND SHALLOW...SO WILL SHOW CHANCE
CATEGORY POPS WHICH SIDE WITH THE LOWER RES MODELS OVER THE DRIER
SOLUTIONS OF MOST HIGHER RES RUNS.
&&
.LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
ASSUMING WE GET THROUGH TONIGHTS SITUATIONAL HEAVY RAIN THREAT
WITHOUT A MAJOR ORDEAL...THE HEAVY RAIN EMPHASIS WE ARE MOST
CONCERNED ABOUT IS OVER THE WEEKEND. A SHARPENING AND HIGH
AMPLITUDE UPPER TROUGH TO THE SOUTHWEST WILL INCREASE POPS
GRADUALLY FRIDAY INTO SATURDAY...AND THEN AGRESSIVELY SATURDAY
NIGHT THROUGH SUNDAY EVENING. A WIDESPREAD HEAVY RAIN OF 1 TO 3
INCHES IS EXPECTED FOR THIS ENHANCED PERIOD WITH ISOLATED HIGHER
AMOUNTS OF 4 TO 6 INCHES POSSIBLE. THE ECMWF AND CANADIAN EVEN
CARRY THE EVENT INTO MEMORIAL DAY...WHICH COULD SEND PROJECTIONS
EVEN HIGHER. FOR NOW...WILL ASSUME THAT A WIDESPREAD MCS OVER THE
WEEKEND SHOULD TEMPORARILY STABILIZE THE AIR FOR MONDAY WHICH
FAVORS THE MORE CONSERVATIVE GFS SOLUTION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 86 69 79 66 83 / 30 50 30 40 40
AUSTIN BERGSTROM INTL AIRPORT 85 68 79 66 83 / 30 50 30 40 40
NEW BRAUNFELS MUNI AIRPORT 86 70 81 67 83 / 30 40 40 40 40
BURNET MUNI AIRPORT 83 66 75 63 80 / 30 60 30 40 40
DEL RIO INTL AIRPORT 86 71 82 69 85 / 20 60 50 60 40
GEORGETOWN MUNI AIRPORT 84 66 76 64 82 / 30 60 30 40 40
HONDO MUNI AIRPORT 86 71 82 68 84 / 20 50 40 50 40
SAN MARCOS MUNI AIRPORT 85 69 79 66 82 / 30 40 30 40 40
LA GRANGE - FAYETTE REGIONAL 86 70 81 69 83 / 30 20 40 30 40
SAN ANTONIO INTL AIRPORT 86 71 81 69 83 / 20 40 40 40 40
STINSON MUNI AIRPORT 87 72 82 69 84 / 20 30 40 40 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...76
SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1224 AM CDT WED MAY 20 2015
.AVIATION...
HIGH CONFIDENCE OF IFR CIGS PREVAILING FOR MOST/IF NOT ALL/ OF
THIS TAF CYCLE. STRONG COLD FRONT IS ON SCHEDULE TO CLEAR LBB
SHORTLY BEFORE 06Z AHEAD OF A SHIELD OF IFR STRATUS AND SOME FOG.
VISBYS HAVE FALLEN TO AS LOW AS 1/2SM AT TIMES BEHIND THE FRONT
AND THIS THREAT SEEMS MOST PRUDENT AT LBB AND PVW WHEREAS NEARBY
SHRA/TSRA AT CDS FOR ANOTHER HOUR SHOULD KEEP THE LOW LEVELS MIXED
TO AVOID POOR VISBYS.
EXTENT OF LOW CIGS AS FAR NORTH AS KANSAS SUGGEST IFR WILL PREVAIL
ALL MORNING AND LIKELY THE AFTERNOON...THOUGH A FEW MODELS
INDICATE CIGS RISING TO MVFR FOR A COUPLE HOURS THIS AFTN BEFORE
RESUMING IFR THEREAFTER.
&&
.PREV DISCUSSION... /ISSUED 914 PM CDT TUE MAY 19 2015/
UPDATE...
UPDATED TO LOWER MIN TEMPS CONSIDERABLY TONIGHT FOR A STRONG COLD
FRONT NOW ENTERING THE FAR SOUTHERN TX PANHANDLE. ABUNDANT
STRATUS AND FOG AS LOW AS 1/2 MILE WAS NOTED BEHIND THIS FRONT AND
THE VISIBILITY AT HEREFORD PLUMMETED FROM 10 MILES TO JUST OVER 1
MILE IN 20 MINUTES. TEMPS IN THE 40S ALREADY ACROSS THE NORTHERN
PANHANDLE CONFIRM THE MAGNITUDE OF COLD ADVECTION...SO HAVE
UPDATED GRIDS LARGELY IN LINE WITH THE LATEST RAP AND HRRR
SOLUTIONS WHICH HAVE A GOOD HANDLE ON THESE TRENDS.
POP-WISE...DROPPED MOST PRECIP MENTION FROM THE CAPROCK
TONIGHT...HOWEVER WE STILL EXPECT SOME STORMS TO RE-DEVELOP WWD
TO NEAR THE I-27 AND HWY 87 CORRIDOR LATER TONIGHT AS THE COLD
FRONT AND TRAILING FRONT ALOFT INTERSECT DEEPER MOISTURE EAST OF
THE RETREATING DRYLINE.
&&
.PREV DISCUSSION... /ISSUED 349 PM CDT TUE MAY 19 2015/
SHORT TERM...
THE MORNING SHOWER AND THUNDER ACTIVITY HAS CLEARED AWAY LEAVING
PLENTY OF SUN TO WARM THE SURFACE. BY MID AFTERNOON WITH RECOVERY
AND WEAK SURFACE PRESSURE FALLS UNDERWAY...SURFACE BASED CAPES HAD
INCREASED TO OVER 3000 JOULES PER KILOGRAM WHILE SURFACE FLOW WAS
MOSTLY SOUTHERLY AND BULK SHEAR VALUES 40+ KNOTS. MOST SHORT RANGE
SOLUTIONS SHOWED SOME DEGREE OF THUNDERSTORM INITIATION WITH THESE
FAVORABLE CONDITIONS LATE THIS AFTERNOON. SEVERAL SHORT CUMULUS
STREETS OVER THE WESTERN SOUTH PLAINS WITHIN A WEAK SURFACE
CONVERGENCE ZONE/DRYLINE...WERE BUBBLING WITH NORTHERN END OF THIS
AREA OVER THE NORTHWESTERN SOUTH PLAINS APPEARING CLOSEST TO
BREAKING OUT ALTHOUGH AS OF YET UNSUCCESSFUL. WITH ABOVE INDICES AND
CURRENT CONDITIONS WE WILL RETAIN A SOLID CHANCE FOR THUNDERSTORMS
AND A POTENTIAL SEVERE THREAT INTO THE EARLY EVENING.
A STATIONARY FRONTAL BOUNDARY ACROSS THE CENTRAL PANHANDLE INTO
WESTERN OKLAHOMA ALSO APPEARS WILL GET SHOVED SOUTHWARD THIS EVENING
AS A SHORT-WAVE UPPER TROUGH ROTATES NORTHWARD THROUGH THE CENTRAL
PLAINS. THIS FRONT MAY LEAD TO MORE ORGANIZED THUNDERSTORMS
SPREADING OUT OF THE PANHANDLE FAVORING NORTH CENTRAL TO NORTHEAST
ZONES...ALTHOUGH SHORT RANGE SOLUTIONS HAVE BEEN TRENDING FURTHER
WEST WITH DEVELOPMENT RECENTLY. AND THIS ACTIVITY WOULD THEN FOLLOW
THE FRONT SOUTHWARD LATER TONIGHT AND EARLY WEDNESDAY...WITH WESTERN
DEVELOPMENT STILL LESS CERTAIN THAN EAST THOUGH ALSO TRENDING MORE
FAVORABLE. BOUNDARY SHOULD MOVE SOUTH OF THE AREA EARLY WEDNESDAY
AND REMAINING THUNDER CHANCES WILL BECOME INCREASINGLY MOST
FAVORABLE SOUTH OF OUR AREA DURING THE DAY WEDNESDAY. TEMPERATURES
HAVE TRENDED SLIGHTLY COOLER FOR MUCH OF THE AREA WEDNESDAY AS WELL.
ANYWAY...WITH SOMEWHAT MARGINAL CONFIDENCE ABOVE IS OUR LATEST
THINKING AND WE HAVE MADE A NUMBER OF ADJUSTMENTS TO MATCH. THE
HEAVY RAIN THREAT MAY REDEVELOP AS WELL OVERNIGHT SHOULD A WELL-
ORGANIZED CONVECTIVE COMPLEX COME TOGETHER BUT SIGNALS TOO MIXED TO
JUMP ALL-IN JUST YET. SO...BE READY FOR POTENTIALLY FAST-BREAKING
WEATHER THROUGH THE NIGHT WITH A BONA-FIDE THOUGH NOT AT ALL CERTAIN
RISK FOR SEVERE STORMS AND STILL AT LEAST LOCALLY HEAVY RAIN
LEADING TO A MINOR FLOODING THREAT. RMCQUEEN
LONG TERM...
THE ACTIVE MAY WEATHER SHOWS NO SIGN OF LETTING UP THROUGH AT LEAST
THIS WEEKEND. THIS WILL OCCUR AS SOME FORM OF SOUTHWESTERLY FLOW
ALOFT PERSISTS OVER WEST TEXAS DOWNSTREAM OF WESTERN CONUS
TROUGHING. THIS UNSETTLED PATTERN WILL PROVIDE MORE OPPORTUNITIES
FOR SEVERE WEATHER AS WELL AS HEAVY RAINFALL.
TO KICK OFF THE EXTENDED...THE SOUTH PLAINS REGION SHOULD FIND
ITSELF NORTH OF A COLD FRONT WITH SURFACE RIDGING AND ABUNDANT CLOUD
COVER PROVIDING COOL AND MOIST CONDITIONS WEDNESDAY NIGHT INTO
THURSDAY. THAT SAID...THERE WILL BE ENOUGH ELEVATED INSTABILITY AND
RETURNING SOUTHEASTERLY FLOW OFF THE DECK THAT ISOLATED TO SCATTERED
SHOWERS/STORMS WILL BE POSSIBLE. A FEW STRONGER ELEVATED STORMS COULD
EVEN OCCUR THOUGH MUTED SURFACE-BASED HEATING/INSTABILITY SHOULD KEEP
THE OVERALL SEVERE THREAT RELATIVELY LOW.
THE COVERAGE AND INTENSITY OF THE CONVECTION MAY TREND UPWARD LATE
THURSDAY INTO EARLY FRIDAY AS A LEAD SHORTWAVE TROUGH IS PROGGED TO
EJECT THROUGH THE SOUTHWEST FLOW OVER THE SOUTHERN HIGH PLAINS.
EVENTUALLY THE WARM FRONT AND WARM SECTOR IS FORECAST TO LIFT NORTH
ACROSS THE AREA OPENING THE DOOR FOR BETTER CHANCES FOR SURFACE-
BASED CONVECTION BY FRIDAY AFTERNOON...THOUGH WHETHER THERE WILL BE
ANY FORCING FOR LARGE-SCALE ASCENT IS UNCLEAR. THAT MAY CHANGE BY
LATE FRIDAY NIGHT INTO EARLY SATURDAY WHEN ANOTHER WEAK UPPER-LEVEL
DISTURBANCE MAY RACE THROUGH THE FLOW. THE WESTERN TROUGH IS THEN
PROGGED TO APPROACH FROM THE WEST ON SATURDAY WITH THE DRYLINE
LIKELY SOMEWHERE NEAR THE TX/NM LINE BY LATE IN THE DAY WHERE IT
WILL PROVIDE A FOCUS FOR CONVECTIVE INITIATION. MODERATE TO STRONG
INSTABILITY AND DEEP-LAYER SHEAR WILL BRING THE RISK FOR SEVERE
STORMS. THIS SAME PATTERN WILL CONTINUE INTO SUNDAY THOUGH THE
DRYLINE AND BEST LARGE-SCALE ASCENT MAY SHIFT EASTWARD A BIT.
A WEAK FRONT MAY SNEAK INTO THE AREA BEHIND THE WEEKEND TROUGH EARLY
MONDAY...BUT IT IS NOT EXPECTED TO HAVE A STRONG PUSH WHICH SHOULD
ALLOW GOOD MOISTURE AND INSTABILITY TO CONTINUE TO RESIDE NEARBY
INTO MUCH OF NEXT WEEK. IT DOES APPEAR THE UPPER FLOW MAY FLATTEN
AND WEAKEN NEXT WEEK...BUT GIVEN THE MAGNITUDE OF THE PROGGED
INSTABILITY AT LEAST ISOLATED LATE DAY STORMS MAY BE POSSIBLE AND
WE HAVE RETAINED SLIGHT CHANCE POPS FROM MONDAY ONWARD.
HIGHS ON THURSDAY WILL ONLY BE IN THE 50S AND 60S...BUT SHOULD
MODERATE INTO THE UPPER 60S TO UPPER 70S FRIDAY BEFORE FURTHER
WARMING INTO THE 70S AND LOWER 80S SATURDAY...WHERE HIGHS WILL
GENERALLY REMAIN THROUGH THE REST OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 50 59 49 69 / 30 50 60 40
TULIA 50 58 49 67 / 30 40 70 60
PLAINVIEW 51 59 51 68 / 30 40 70 60
LEVELLAND 52 60 52 72 / 40 60 60 50
LUBBOCK 51 61 52 71 / 40 50 70 60
DENVER CITY 54 61 52 75 / 40 60 60 50
BROWNFIELD 54 61 52 74 / 40 60 60 50
CHILDRESS 53 64 55 71 / 30 20 60 60
SPUR 53 62 53 72 / 40 40 60 60
ASPERMONT 56 65 56 77 / 50 40 60 60
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/31
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1200 AM CDT Wed May 20 2015
.AVIATION...
/06Z TAFS/
Look for challenging flight weather during the next 24 hours.
Stratus is already return to our southern terminals. Others will
follow soon. Another cold front will push into the Big Country
before noon tomorrow. This front may stall somewhere across the
Concho Valley. Thunderstorms will likely develop along and near
this boundary.
&&
.PREV DISCUSSION... /ISSUED 602 PM CDT Tue May 19 2015/
AVIATION...
/00Z TAFS/
Scattered showers and thunderstorms are affecting mainly the KABI
TAF this evening, where a VCTS group was included. Elsewhere,
convection should remain isolated. Stratus will move back into all
of the TAF sites after 06z, resulting in MVFR/IFR ceilings. VFR
ceilings should return to all sites by late morning or early
afternoon Wednesday. A cold front will approach KABI around 17z,
then slowly move south. Scattered showers and thunderstorms will
be possible along and behind the front, along with a wind shift to
the north at 8 to 12 knots.
PREV DISCUSSION... /ISSUED 353 PM CDT Tue May 19 2015/
SHORT TERM...
(Today and Tonight)
.Flash flood Watch has been extended until 10 PM CDT tonight for
the Big Country, Concho Valley, and Heartland...
The atmosphere is unstable this afternoon with RUC SB CAPES of
4000 J/KG. Severe storms are certainly possible this afternoon and
evening with the very strong instability. Strong storms were
already developing in the Trans Pecos and eastern Permian basin,
where less stratus was bringing more heating and instability.
These will likely move eastward into the Concho Valley this
evening. Scattered showers and thunderstorms were also developing
from Robert Lee to Brownwood, then northward into the Big Country.
With saturated soil conditions from Wednesday storms, the flash
flood watch has been extended to 10 PM CDT to catch the evening
storms. While coverage is expected to be less, excessive rainfall
rates from slow moving storms will likely cause localized flash
flooding on saturated soils. The atmosphere remains very moist,
with the SPC mesoanalysis page indicating very high precipitable
waters of 1.5 to 1.7 inches, which could bring very efficient
rainfall production.
Wednesday, a cold front will move into the Big Country in the
afternoon, and through the rest of West Central Texas overnight.
The atmosphere will remain unstable, and the front may be a
focus for severe thunderstorm development and localized flooding.
04
LONG TERM...
(Wednesday night through Tuesday)
The slow moving cold front is forecast to be near the I-20
corridor by Wednesday evening. A potent shortwave trough is
progged to be lifting northeast across Far West TX by this time,
increasing large scale forcing for ascent. Precipitable water
values will be in the 1.4 to 1.6" range, providing ample moisture
for convective development. As thunderstorms develop along/north
of this cold front, southerly winds above the boundary layer will
feed Gulf moisture into the complex. This will help propagate the
cold front slowly south across the CWA through Thursday morning,
with east to northeast surface winds developing across West
Central TX. Relatively weak winds aloft will result in slower
storm motions, enhancing the potential for locally heavy rainfall.
Another Flash Flood Watch may be required for this period.
The best rain chances shift to the southern zones on Thursday as
slightly drier air advects into the area behind this cold front.
Cooler temperatures are anticipated on Thursday, with highs in the
mid/upper 60s across the Big Country to the mid 70s along the I-10
corridor. The next shortwave trough is progged to approach West TX
Thursday and Thursday night. Rain chances ramp up accordingly, as
fairly widespread convection is anticipated across West Central
TX. Additional locally heavy rainfall will be possible during the
overnight hours.
Southerly winds are forecast to resume on Friday as the
aforementioned surface boundary washes out. Temperatures are
expected to respond by warming into the upper 70s to lower 80s.
Again, showers and thunderstorms will be possible, especially
during the afternoon and evening hours as thunderstorms over the
Permian Basin drift east into West Central TX.
The weather pattern over the weekend suggests a potential not only
for heavy rainfall, but also for severe weather. Southwest flow
aloft increases as a strong shortwave trough moves slowly east
across the Four Corners. Warmer surface temperatures, rich Gulf
moisture, and steepening mid-level lapse rates will increase the
potential for strong to severe thunderstorms.
In summary, showers and thunderstorms will be possible areawide
through Monday. The severe weather threat will be relatively low,
albeit still present. The potential for severe thunderstorms will
increase this weekend. Heavy rainfall will be the primary concern
through the period. Total rainfall amounts exceeding 4 inches are
possible.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 68 78 59 69 60 / 30 40 50 30 60
San Angelo 68 83 63 73 63 / 20 30 60 40 60
Junction 69 83 67 77 65 / 20 20 60 50 50
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1147 PM CDT TUE MAY 19 2015
.AVIATION...
HIGH CONFIDENCE OF IFR CIGS PREVAILING FOR MOST/IF NOT ALL/ OF
THIS TAF CYCLE. STRONG COLD FRONT IS ON SCHEDULE TO CLEAR LBB
SHORTLY BEFORE 06Z AHEAD OF A SHIELD OF IFR STRATUS AND SOME FOG.
VISBYS HAVE FALLEN TO AS LOW AS 1/2SM AT TIMES BEHIND THE FRONT
AND THIS THREAT SEEMS MOST PRUDENT AT LBB AND PVW WHEREAS NEARBY
SHRA/TSRA AT CDS FOR ANOTHER HOUR SHOULD KEEP THE LOW LEVELS MIXED
TO AVOID POOR VISBYS.
EXTENT OF LOW CIGS AS FAR NORTH AS KANSAS SUGGEST IFR WILL PREVAIL
ALL MORNING AND LIKELY THE AFTERNOON...THOUGH A FEW MODELS
INDICATE CIGS RISING TO MVFR FOR A COUPLE HOURS THIS AFTN BEFORE
RESUMING IFR THEREAFTER.
&&
.PREV DISCUSSION... /ISSUED 914 PM CDT TUE MAY 19 2015/
UPDATE...
UPDATED TO LOWER MIN TEMPS CONSIDERABLY TONIGHT FOR A STRONG COLD
FRONT NOW ENTERING THE FAR SOUTHERN TX PANHANDLE. ABUNDANT
STRATUS AND FOG AS LOW AS 1/2 MILE WAS NOTED BEHIND THIS FRONT AND
THE VISIBILITY AT HEREFORD PLUMMETED FROM 10 MILES TO JUST OVER 1
MILE IN 20 MINUTES. TEMPS IN THE 40S ALREADY ACROSS THE NORTHERN
PANHANDLE CONFIRM THE MAGNITUDE OF COLD ADVECTION...SO HAVE
UPDATED GRIDS LARGELY IN LINE WITH THE LATEST RAP AND HRRR
SOLUTIONS WHICH HAVE A GOOD HANDLE ON THESE TRENDS.
POP-WISE...DROPPED MOST PRECIP MENTION FROM THE CAPROCK
TONIGHT...HOWEVER WE STILL EXPECT SOME STORMS TO RE-DEVELOP WWD
TO NEAR THE I-27 AND HWY 87 CORRIDOR LATER TONIGHT AS THE COLD
FRONT AND TRAILING FRONT ALOFT INTERSECT DEEPER MOISTURE EAST OF
THE RETREATING DRYLINE.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
153 AM EDT WED MAY 20 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE EAST TODAY...FOLLOWED
BY AN AREA OF LOW PRESSURE THAT WILL AFFECT THE REGION
THURSDAY. DRY AND TRANQUIL WEATHER EXPECTED FOR FRIDAY AND
SATURDAY COURTESY OF DRY HIGH PRESSURE.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 145 AM EDT WEDNESDAY...
FAIR/DRY WEATHER TODAY AND AS HIGH PRESSURE WHICH IS BUILDS INTO
THE MID ATLANTIC REGION FROM THE NORTHWEST. TEMPERATURES NEAR
NORMAL WITH 70S TO AROUND 80 FOR HIGHS. OVERNIGHT LOWS WILL BE
HELD UP SOMEWHAT..GENERALLY IN THE 50S TO NEAR 60 BY ADVANCING
HIGH CLOUDS AHEAD OF NEXT WEATHER SYSTEM WHICH WILL AFFECT AREA ON
THURSDAY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 330 PM EDT TUESDAY...
A GOOD DEGREE OF UNCERTAINTY IN THE FORECAST EARLY IN THE SHORT TERM
PERIOD AS GUIDANCE DIFFERENCES ON HANDLING OF SURFACE FEATURES...
WHICH WILL HAVE AN IMPACT ON RAIN CHANCES WEDNESDAY NIGHT THROUGH
THURSDAY. SHORT WAVE ENERGY EJECTING OUT OF AN WESTERN UPPER LEVEL
RIDGE WILL COMBINE WITH SOME SHORT WAVE ENERGY ROTATING AROUND AN
UPPER TROF OVER THE GREAT LAKES AND HEAD IN OUR DIRECTION. THIS
WILL HELP DRIVE DEVELOPMENT OF A SURFACE LOW OVER THE SOUTHEAST US
LATE WEDNESDAY NIGHT...WHICH WILL THEN MOVE OFF THE MIDDLE ATLANTIC
COAST BY THURSDAY NIGHT. THE OPERATIONAL GFS RUN IS ON BOARD WITH
OTHER MODELS IN HANDLING OF DYNAMICS BUT IS MUCH LESS AGGRESSIVE AND
FURTHER EAST IN DEVELOPING PRECIPITATION OVER THE AREA. OTHER
OPERATIONAL RUNS AND ENSEMBLES DO GENERATE A MUCH MORE COHESIVE
PRECIPITATION SHIELD NORTH AND WEST OF THE LOW ASSOCIATED WITH
ENHANCED LIFT IN DEFORMATION AREAS AND RR QUAD OF UPPER JET WHERE WE
NORMALLY EXPECT TO SEE THESE FEATURES. THUS WILL LEAN TOWARD THE
WETTER GUIDANCE AND RAMP POPS UP TO HIGH CHANCE FOR MOST AREAS BY
LATE WED NIGHT AND THROUGH THURSDAY. BELIEVE THUNDER CHANCES WILL
STAY JUST SOUTH OF THE FOOTHILLS/PIEDMONT OF NC SINCE WE WILL BE IN
A COOLER AND MORE STABLE ENVIRONMENT WITH THE LOW TRACKING TO OUR
SOUTH. AS THE LOW DEPARTS THURSDAY NIGHT...HIGH PRESSURE WILL BUILD
IN FROM THE UPPER MIDWEST AND WE WILL SEE STEADILY IMPROVING
CONDITIONS WITH QUIET WEATHER EXPECTED AS WE HEAD INTO THE WEEKEND.
TEMPERATURES WILL START OFF A BIT COOL ON THURSDAY WITH
PRECIPITATION ON THE COOL SIDE OF THE LOW...BUT VALUES WILL REBOUND
TO SEASONAL LEVELS WITH GENERALLY UPPER 60S/AROUND 70 BLUE RIDGE
WEST AND LOW TO MID 70S EAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 PM EDT TUESDAY...
UPPER PATTERN WILL BE DEVELOPING A LARGE TROF OVER THE EASTERN US
DURING THE EXTENDED PERIOD...WITH A BERMUDA HIGH OFF THE COAST. THIS
WILL GIVE US A VERY COMFORTABLE AND PLEASANT SATURDAY FOLLOWED BY
HEAT AND HUMIDITY MOVING BACK INTO THE REGION BY SUNDAY...WITH THE
TRULY UNCOMFORTABLE CONDITIONS HOLDING OFF UNTIL THE FIRST PART OF
NEXT WEEK. HOWEVER THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE
ONLY MODEST AS SIGNIFICANT DYNAMIC FORCING WILL BE ABSENT...LEAVING
US TO RELY ON OROGRAPHIC FORCING FROM THE BLUE RIDGE WEST TO FOCUS
LIFT AND GENERATE SOME CONVECTIVE ACTIVITY. PWATS WILL ONCE AGAIN BE
RISING ABOVE ONE INCH SO THE POSSIBILITY OF LOCAL DOWNPOURS WILL BE
INCREASING. BY TUESDAY A COLD FRONT WILL BE APPROACHING FROM THE
WEST AND LOOKS TO BRING GREATER COVERAGE OF PRECIPITATION TO THE
REGION TUESDAY AFTERNOON AND EVENING. AFTER A COMFORTABLE
SATURDAY...EXPECT RISING TEMPERATURES TO BE ABOUT 10 DEGREES ABOVE
NORMAL AS WE HEAD INTO NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 145 AM EDT WEDNESDAY...
VFR CONDITIONS EXPECTED TO PREVAIL IN REST OF THE OVERNIGHT AND
EARLY MORNING AS HIGH PRESSURE OVER THE GREAT LAKES RIDGES INTO
CENTRAL MID-ATLANTIC REGION. EVEN KLWB MAINTAINING LIGHT NW WINDS
AT THIS TIME AND A WIDE T-TD SPREAD WITH LITTLE LIKELIHOOD OF FOG
DEVELOPMENT. HIGH OVERCAST IN ADVANCE OF FAST-MOVING SYSTEM
EXPECTED BY THE EVENING BUT NO IMPACT TO AVIATION.
EXTENDED AVIATION DISCUSSION...
AN UPPER LEVEL DISTURBANCE WILL LIKELY BRING SOME MVFR CEILINGS
AND SHOWERS BACK INTO THE AREA THURSDAY...MOVING OUT FRIDAY
MORNING...WITH VFR CONDITIONS RETURNING FRIDAY AFTERNOON AND
SATURDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...MBS
LONG TERM...MBS
AVIATION...AMS/PC
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
912 PM CDT THU MAY 21 2015
.UPDATE...SCATTERED SHOWERS SHOWING A DIMINISHING TREND LAST 30
MINUTES OR SO...BUT AT LEAST ISOLATED SHOWERS SHOULD CONTINUE
NEXT SEVERAL HOURS AS LOW LEVEL FRONTOGENETICAL FORCING SLIDES
THROUGH SOUTHEAST WI. GUSTY NORTH TO NORTHEAST IN WAKE OF BACKDOOR
COLD FRONT CURRENTLY MOVING THROUGH MILWAUKEE WILL SLIDE SOUTH
THROUGH REST OF CWA THROUGH 09Z OR SO. OVERNIGHT TEMPS LOOK IN
GOOD SHAPE.
&&
.AVIATION/06Z TAFS/...SCATTERED SHOWERS WILL DIMINISH THROUGH
MIDNIGHT ACROSS SOUTHEAST WI AS LOW LEVEL FRONTOGENETICAL FORCING
WEAKENS AND SLIDES SOUTH OF THE AREA. GUSTY NORTHEAST WINDS WILL
AFFECT ERN TAF SITES FOR SEVERAL HOURS BEFORE SETTLING DOWN. VFR
CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
&&
.MARINE...COLD FRONT ACCELERATING SOUTH ACROSS THE NEARSHORE
WATERS IS OVER NORTHERN LMZ645 AND WILL SWEEP SOUTH ACROSS THE
REST OF LMZ645 AND LMZ646 THRU 04-05Z. SOUTHWEST WINDS ABRUPTLY
VEER TO THE NORTHEAST WITH A FEW GUSTS TO 25 TO 30 KNOTS IN ITS
WAKE. EXPECT 1-3 HOURS OF GUSTY WINDS BEFORE THEY SETTLE DOWN. DUE
TO EXPECTED BRIEF NATURE OF THE GUSTINESS...WL HOLD OFF ON SMALL
CRAFT ADVY. CONSULT LATEST MARINE WEATHER STATEMENT FOR MORE
DETAILS. WAVES WILL BRIEFLY RISE TO 2 TO 4 FEET IN GUSTY ONSHORE
FLOW BEFORE SETTLING SUBSIDING.
&&
.PREV DISCUSSION... /ISSUED 323 PM CDT THU MAY 21 2015/
TONIGHT - CONFIDENCE...MEDIUM
DRY AND MILD WESTERLY FLOW WILL PERSIST INTO THE EARLY EVENING
HOURS. FRONTAL BOUNDARY THEN PROGGED TO SWEEP SOUTH AND SHIFT
WINDS TO THE NE. ALREADY SEEING SOME NORTHERLY 20 KNOT PLUS GUSTS
ACRS NRN WI WITH WEAK POST FRONTAL PRESSURE RISES VCNTY U.P. SO NE
GUSTINESS EXPECTED ESPECIALLY NEAR LAKE MICHIGAN. WILL LEAVE
MENTION OF A FEW SHRA IN PARTS OF THE ERN CWA THIS EVENING. KGRB
RADAR SHOWS A FEW SHRA POPPING UP WITHIN AGITATED CU FIELD VCNTY
FRONTAL BOUNDARY. HIGH PRESSURE SETTLES IN LATER IN THE NIGHT.
FRIDAY - CONFIDENCE...HIGH
SURFACE HIGH PRESSURE EXPECTED TO DOMINATE WITH PLENTY OF SUNSHINE AND
LIGHT WIND REGIME. ONSHORE COMPONENT WILL KEEP THE EAST COOLER. 925
TEMPS RISE TO AROUND 9C IN THE EAST AND 14C IN THE WEST...SO EXPECT
A DECENT EAST/WEST GRADIENT IN TEMPS.
SHORT TERM...FRIDAY NIGHT THROUGH SUNDAY NIGHT.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE HIGH
SURFACE HIGH CENTERED OVER LOWER MICHIGAN SHIFTS SLOWLY TO THE
SOUTHEAST AND EXPANDS. WARMING 850 MB TEMPS AS COLD POOL MOVES EAST
WITH DEPARTING SRN CANADIAN CLOSED LOW...AND 500 MB HEIGHTS SLOWLY
RISE AS DEEPENING TROUGH MOVES INTO WESTERN U.S. WILL SEE LOWS HOLD
IN THE UPPER 40S IN THE SW THIRD...WITH LOW TO MID 40S ELSEWHERE.
SOME 700 MB MOISTURE AND OMEGA MOVE ACROSS WESTERN WI SATURDAY
AFTERNOON...BUT STRONGER Q-VECTOR CONVERGENCE STAYS TO THE WEST WITH
MORE FOCUSED 850 MB WARM AIR ADVECTION AND LOWER CONDENSATION
PRESSURE DEFICITS. SOUNDINGS ARE ALSO DRY BELOW 5K FT REFLECTING
INFLUENCE OF LOBE OF SURFACE HIGH PRESSURE EXTENDING WESTWARD OVER
SRN WI FROM BROAD HIGH CENTERED OVER THE MID-ATLANTIC STATES. NO
MORE THAN SLIGHT POPS WARRANTED AND WILL KEEP LIMITED TO THE FAR NW.
SOME DIFFERENCES IN HOW WARM 925 MB TEMPS GET SO CONSENSUS HIGHS IN
THE LOWER 70S AWAY FROM LAKE MICHIGAN LOOK GOOD WITH UPPER 60S
LAKESIDE.
SATURDAY NIGHT...FORECAST CONFIDENCE HIGH
JET SHIFTS NWD WITH UPPER RIDGING DEVELOPING OVER CENTRAL SECTIONS
OF THE COUNTRY IN RESPONSE TO DEEP FULL-LATITUDE TROUGH DIGGING INTO
THE SW U.S. PCPN CHANCES ARE PREDICATED ON TIMING OF PRECURSOR SHORT
WAVES EJECTING AHEAD OF DEEP WESTERN U.S. TROUGH AND LIFTING TOWARD
THE WESTERN GREAT LAKES IN MOIST SLY FLOW.
FIRST SHORT WAVE APPROACHES...WITH TIMING DIFFERENCES CAUSING PCPN
CHANCES THROUGH 12Z SUNDAY TO RANGE FROM KEEPING THE ENTIRE CWA
DRY/12Z GFS/...TO BRINGING PCPN INTO THE WEST OR FAR SOUTH/NAM AND
12ZECMWF/...OR OVER ALL BUT THE FAR NORTH AND EAST/12Z CANADIAN.
WILL FOLLOW CONSENSUS POPS WHICH LIMITS CHANCE POPS TO THE SOUTH
CENTRAL AND SLIGHT CHANCE ELSEWHERE WITH LESS THAN 15 PCT IN THE FAR
SOUTHEAST. LOWS WILL HOLD IN THE 50S OVERNIGHT WITH RISING 925 MB
TEMPS
SUNDAY AND SUNDAY NIGHT...FORECAST CONFIDENCE MEDIUM
ALL MODELS SWING INITIAL SHORT WAVE ACROSS SRN WI SUNDAY
MORNING...WITH ANOTHER WARM ADVECTION SURGE APPROACHING THE FAR
SOUTH BY 00Z MONDAY. HIGHER RESOLUTION VERSIONS OF GFS AND NAM
INDICATE THERE WILL PROBABLY SEE A BREAK IN THE PCPN BETWEEN THESE
TWO ROUNDS...BUT MODEL TIMING UNCERTAINTY LEADS TO POPS ALL DAY IN
THE CONSENSUS POPS. BETTER POPS SUNDAY NIGHT WITH WARM ADVECTION
SURGE. HOPEFULLY LATER RUNS WILL LEAD TO BETTER RESOLUTION TO PCPN
TIMING.
IF BREAK IN PCPN IS LONG ENOUGH...AND A BIT OF SUN CAN POP
THROUGH...COULD SEE TEMPS RISE HIGHER THAN UPPER 60S TO LOWER 70S
WITH FORECAST 925 MB TEMPS. INSTABILITY IN SOUNDINGS NOT THAT
IMPRESSIVE SO WILL LIMIT CHANCES OF THUNDER. LOWS WILL ONLY COOL
INTO THE UPPER 50S TO AROUND 60 NEAR THE IL BORDER.
LONG TERM...MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM
AN UNSETTLED AND WET PERIOD IN OVERALL SWLY MID TO UPPER LEVEL FLOW
AS WESTERN TROUGH MOVES OUT INTO THE PLAINS MONDAY...AND THEN
DAMPENS AS IT CROSSES THE UPPER MIDWEST TUESDAY AND IS ABSORBED INTO
A CLOSED LOW OVER HUDSON BAY. MOIST SRLY SURFACE FLOW CONTINUES AS
SURFACE LOW PASSES BY TO THE WEST AND NORTH OF THE STATE. GFS AND
ECMWF BRING ANOTHER SURGE OF MOISTURE WITH A SHORT WAVE TUESDAY
NIGHT...WITH THE GFS DEVELOPING A SURFACE LOW THAT MOVES RIGHT ACROSS
THE STATE WEDNESDAY. ECMWF DRIES AREA OUT WEDNESDAY INTO
THURSDAY...WITH ANOTHER WAVE MOVING IN FOR THURSDAY AFTERNOON/NIGHT.
GFS KEEPS AREA DRY ONCE PCPN ENDS WEDNESDAY EVENING. RESULT IS
CHANCE POPS THROUGH THE EXTENDED WITH BLENDED SOLUTION. LOOKING FOR
ABOVE NORMAL TEMPERATURES THROUGH THE EXTENDED.
AVIATION/00Z TAFS/...VFR THIS PERIOD WITH WESTERLY SURFACE FLOW
AHEAD OF FRONT DROPPING SOUTHWARD FROM NRN WI. PREFER THE DRIER LOOK
OF THE HRRR WITH RESPECT TO PRECIP COVERAGE. LATEST GUIDANCE
SUGGESTS FRONT DROPS THROUGH TAF SITES BETWEEN 01Z-03Z. BRIEF PERIOD
OF GUSTY NE WINDS POSSIBLE. HAVE ALSO KEPT THE EVENING POPS WITH
THIS FEATURE AS WELL. NAM/RAP SOUNDINGS SHOW LITTLE POTENTIAL FOR
POST FRONTAL MVFR CIGS. QUIET HIGH PRESSURE DOMINATES FOR FRIDAY.
MARINE...A COLD FRONT WILL RACE DOWN THE LAKE EARLY THIS
EVENING...REACHING SHEBOYGAN AROUND 7 PM AND KENOSHA BY 9-10PM THIS
EVENING. WINDS WILL SHIFT ABRUPTLY FROM WESTERLY TO NORTHEAST AND
MAY GUST TO AROUND 20KTS POST FROPA FOR A TIME BEFORE SETTLING BACK
DOWN.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 PM CDT WED MAY 20 2015
.UPDATE...
ISSUED AT 937 AM CDT WED MAY 20 2015
INCREASED/MOVED PRECIPITATION CHANCES A BIT MORE NORTHWARD ACROSS
NORTHEAST IA/SOUTHWEST WI THIS MORNING INTO THIS AFTERNOON WITH
INCOMING MID-LEVEL TROUGH/CIRCULATION. LATEST RAP SHOWS
INTENSIFICATION IN MID-LEVEL/700MB FRONTOGENESIS...SO EXPECTING
DESPITE DRYER LOW LEVELS...THE F-GEN WILL BE STRONG ENOUGH TO
GENERATE SOME SHOWERS.
UPDATE ISSUED AT 802 AM CDT WED MAY 20 2015
UPDATED TO REMOVE FROST ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS THIS PERIOD...SMALL -SHRA CHANCES SOUTH TODAY...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD A BROAD AREA OF HIGH PRESSURE OVER THE
NORTHERN PLAINS AND UPPER MIDWEST. THE HIGH WAS BRINGING CLEAR
SKIES AND SUB-FREEZING TEMPS TO MUCH OF NORTHERN MN/WI INTO
CENTRAL WI EARLY THIS MORNING. WV IMAGERY SHOWED A RATHER VIGOROUS
LOOKING SHORTWAVE MOVING EAST ALONG THE NEB/SD BORDER. MID/HIGH
CLOUDS WITH THIS WAVE SPREADING ACROSS SOUTHERN MN/WI...HELPING
KEEP TEMPS ABOVE FREEZING. THE SHORTWAVE WAS BRINGING SOME LOWER
LEVEL MOISTURE TO IA...BUT EVEN THERE CLOUDS WERE MOSTLY ABOVE 5K-
6K FT. REGIONAL RADARS SHOWED REFLECTIVITY WITH THE SHORTWAVE FROM
SOUTH- CENTRAL SD TO NORTHERN MO BUT SFC OBS SHOW PRECIP REACHING
THE GROUND WAS MAINLY ALONG/SOUTH OF I-80 EARLY THIS MORNING.
20.00Z MODEL INITIALIZATIONS LOOK GOOD. MODELS OFFER A TIGHTER
CONSENSUS ON THE SD/NEB SHORTWAVE AS IT TRACKS EAST TODAY...AHEAD OF
BUT PARTLY PHASING WITH THE NORTHERN STREAM SHORTWAVE DROPPING INTO
EASTERN SD. TREND IS TO KEEP THE WAVES AS 2 SEPARATE PIECES OF
ENERGY QUICKLY FOLLOWING EACH OTHER THRU A MERGED TROUGH OVER THE
UPPER MIDWEST. TREND FAVORS STRONGER OF THE EARLIER MODELS AS THE
NORTHERN STREAM SHORTWAVE MOVES SOUTHEAST ACROSS THE REGION. WITH
THE TIGHT CONSENSUS OF SOLUTIONS...SHORT TERM FCST CONFIDENCE IS
GOOD THIS CYCLE.
IN THE SHORT TERM...SMALL -SHRA CHANCES ACROSS THE FAR SOUTH END OF
THE FCST AREA REMAIN A BATTLE OF 700-500MB FN/QG CONVERGENCE AND PV
ADVECTION WITH THE SHORTWAVE AND OVERCOMING DRIER NORTH TO NORTHEAST
FLOW/AIRMASS IN THE SFC-700MB PORTION OF THE COLUMN. PW VALUES IN
THE 0.5 TO 0.75 INCH RANGE ACROSS THE SOUTH END OF THE FCST AREA
TODAY BUT MAIN 850MB MOISTURE TRANSPORT STAYS WELL SOUTH IN MO AND
THE 700MB TRANSPORT MAINLY REACHES INTO THE SOUTHERN 2/3 OF IA.
MODELS...INCLUDING LOCAL/REGIONAL WRF MODELS ABOUT EVENLY SPLIT ON
-SHRA MAKING IT AS FAR NORTH AS THE KCCY/KOLZ AREAS. CONTINUED SOME
20-40 PERCENT -SHRA CHANCES ACROSS PARTS OF NORTHEAST IA INTO
EXTREME SOUTHWEST WI TODAY...PARTLY TO BLEND WITH NEIGHBORING GRIDS.
MAIN SHOT OF FORCING/LIFT MOVES ACROSS THE AREA THIS MORNING AND
CARRIED HIGHEST RAIN CHANCES AROUND 15Z...WITH RAIN CHANCES
DIMINISHING THRU THE AFTERNOON AS THE LEAD SHORTWAVE PASSES AND THE
COLUMN BEGINS TO DRY. MID/HIGH CLOUDS ACROSS THE AREA TODAY WILL
TEMPER HIGHS. 700-500MB TROUGH AXIS DROPS SOUTH OF THE AREA THIS
EVENING WITH AN INCREASE OF NORTHWEST TO NORTH FLOW AND DRIER AIR
SPREADING SOUTH ACROSS THE FCST AREA. CLOUDS LOOKING TO DECREASE
THIS EVENING WITH MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT. ANOTHER
COOL NIGHT TONIGHT UNDER MOSTLY CLEAR SKIES...A DRY LOW LEVEL
AIRMASS AND WINDS EXPECTED TO BE LIGHT. MAY YET BE SOME PATCHY FROST
ACROSS THE NORTHEAST END OF THE FCST AREA LATE TONIGHT INTO EARLY
THU MORNING. WILL LEAVE IT TO DAY CREW TO FURTHER EVALUATE THIS
AFTER THE CURRENT ADVISORY HAS EXPIRED. FAVORED A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...TEMPERATURES.
20.00Z MODELS IN GOOD AGREEMENT ON NORTHWEST FLOW ALOFT OVER THE
UPPER MIDWEST THU THRU FRI...AND REMAIN IN GOOD AGREEMENT FOR HGTS
TO RISE/RIDGING TO BUILD INTO THE REGION FRI NIGHT. MODELS ALSO WITH
RATHER GOOD RUN-TO-RUN CONSISTENCY THIS PERIOD. TREND BY FRI NIGHT
IS TOWARD STRONGER OF THE EARLIER RUNS WITH THE RIDGING OVER THE
REGION. FCST CONFIDENCE FOR THU THRU FRI NIGHT IS GOOD THIS CYCLE.
UNDER THE NORTHWEST FLOW ALOFT MODEL SOUNDINGS AND TIME-HGT X-
SECTIONS SHOWING A RATHER DRY AIRMASS/COLUMN OVER THE AREA FOR
THU THRU FRI. OTHER THAN PERHAPS SOME SCT AFTERNOON CUMULUS DURING
PEAK HEATING...THU THRU FRI SHAPING UP TO BE A CLEAR/SUNNY PERIOD.
DECENT CONSENSUS AMONG THE MODEL FOR A WEAK WAVE TO DROP ACROSS
THE WESTERN GREAT LAKES THU BUT ANY IMPACTS FROM THIS LOOKING TO
REMAIN WELL EAST OF THE FCST AREA. SFC PRESSURE GRADIENTS ON THE
WEAK SIDE FOR LIGHT WINDS...ESPECIALLY FRI WITH A SFC RIDGE AXIS
OVER THE REGION. MODEL SOUNDINGS INDICATING MIXING TO ABOUT 750MB
THU...WITH AROUND 25KTS OF WIND IN THE 850-750MB PORTION OF THE
MIXED LAYER. INCREASED WINDS/GUSTS A BIT THU AFTERNOON. COLUMN
MIXES TO AROUND 825MB FRI...WITH WINDS PROGGED TO BE LESS THAN
10KT THRU 800MB. 850MB TEMPS IN THE +7C TO +9C RANGE BOTH THU/FRI
AFTERNOONS... SUPPORTING HIGHS IN THE UPPER 60S TO NEAR 75. LIGHT
WINDS AND CLEAR SKIES FOR STRONGER RADIATIONAL COOLING THU
NIGHT...FOR A LARGER THAN NORMAL DIURNAL SWING OF TEMPERATURES. AS
PATTERN PROGRESSES FRI NIGHT...SFC-700MB TROUGHING STRENGTHENS IN
THE PLAINS. INCREASING SOUTH TO SOUTHWEST LOW LEVEL FLOW STARTS TO
SPREAD MOISTURE/WARMING NORTHEAST INTO THE UPPER MIDWEST...ALONG
WITH HIGHER LEVEL MOISTURE AHEAD OF THE WESTERN CONUS TROUGHING
SPILLING THRU THE RIDGING AND INTO THE REGION. TREND OF WARMER
LOWS AND SOME INCREASE OF CLOUDS FRI NIGHT LOOKS GOOD. TRENDED
TOWARD WARMER OF GUIDANCE HIGHS THU/FRI...THEN FAVORED A BLEND OF
THE GUIDANCE LOWS THU/FRI NIGHTS.
FOR SATURDAY THRU TUESDAY...DAYS 4 TO 7...
MEDIUM RANGE MODEL RUNS OF 20.00Z IN QUITE GOOD AGREEMENT SAT/SUN
SHOWING THE MID LEVEL RIDGE AXIS TO SLOWLY MOVE EAST OF THE REGION
AND DEEP SOUTHWEST FLOW ALOFT OVER MUCH OF THE UPPER MIDWEST BY LATE
SUN. DIFFERENCES BEGIN TO APPEAR BY SUN NIGHT/MON...ON THE TIMING/
STRENGTH DETAILS OF SHORTWAVE ENERGY EJECTING OUT OF THE WESTERN
CONUS TROUGH AND TOWARD/INTO THE UPPER MIDWEST. DETAIL DIFFERENCES
CONTINUE TUE...BUT GENERAL LONGWAVE CONSENSUS FOR BROAD TROUGHING
OVER MUCH OF THE CENTRAL/WESTERN CONUS. WITH THIS TRENDING TO BE A
MORE UNSETTLED WEATHER PERIOD AND SENSIBLE WEATHER ANY ONE DAY
STRONGLY IMPACTED BY THE SHORTWAVE/MESO-SCALE DETAILS...FCST
CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE THIS CYCLE.
MODEL CONSENSUS HAS SOUTHERLY FLOW AND MOISTURE CONTINUING TO
INCREASE INTO THE UPPER MIDWEST SATURDAY THRU SUN. PW VALUES PROGGED
IN THE 1.5 INCH RANGE OVER MUCH OF THE FCST AREA BY 12Z SUN. THIS
WITH A BROAD INCREASE OF LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT AND
INSTABILITY. MODEL CONSENSUS OF INCREASING SHRA/TSRA CHANCES FROM
WEST TO EAST ACROSS THE AREA FROM SAT THRU SUN NIGHT LOOKING WELL
TRENDED...THOUGH THE SPECIFIC DETAILS OF PERIOD HAVE YET TO BE
SORTED OUT. WITH SLOW PROGRESSION OF THE LONGWAVE PATTERN...AND
ADDITIONAL SHORTWAVES TO COME THRU LONGWAVE TROUGHING THAT IS
PROGGED TO REMAIN OVER THE WEST HALF OF THE CONUS...THE MODEL/
ENSEMBLE CONSENSUS SHRA/ TSRA CHANCES CONTINUING THRU MON/TUE ARE
REASONABLE FOR NOW. GIVEN UNCERTAINTIES WITH SHRA/TSRA CHANCES/
TIMING/COVERAGE /AND CLOUD COVER/ ANY ONE DAY...DID NOT DEVIATE
FROM THE MODEL CONSENSUS HIGHS/LOWS FOR SAT THRU TUE. IF ANY ONE
OR MORE OF DAYS 4 TO 7 END UP DRY AND SUNNIER THAN CURRENTLY
EXPECTED... HIGHS THAT DAY COULD EASILY BE 5F TO 10F WARMER THAN
THOSE IN THE FCST GRIDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1201 PM CDT WED MAY 20 2015
CURRENTLY TRACKING A MID-LEVEL TROUGH/CIRCULATION OVER NORTHWEST
IA. SO FAR...RAIN SHOWER ASSOCIATED WITH THIS WAVE ARE REMAINING
SOUTH OF THE KRST/KLSE TAF SITES WITH JUST BROKEN/OVERCAST VFR
MID-LEVEL CLOUD IN PLACE. THIS WAVE WILL CONTINUE TO PASS SOUTH OF
THE AREA THIS EVENING...KEEPING VFR CONDITIONS GOING AT KRST/KLSE
TAF SITES. WILL BE WATCHING ANOTHER TROUGH DROP SOUTH ACROSS THE
AREA OVERNIGHT INTO THURSDAY. WITH VFR CONDITIONS EXPECTED...MAIN
IMPACT WILL BE INCREASING WESTERLY WINDS THURSDAY IN THE 10-20KT
RANGE AS THE TROUGH DROPS THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
937 AM CDT WED MAY 20 2015
.UPDATE...
ISSUED AT 937 AM CDT WED MAY 20 2015
INCREASED/MOVED PRECIPITATION CHANCES A BIT MORE NORTHWARD ACROSS
NORTHEAST IA/SOUTHWEST WI THIS MORNING INTO THIS AFTERNOON WITH
INCOMING MID-LEVEL TROUGH/CIRCULATION. LATEST RAP SHOWS
INTENSIFICATION IN MID-LEVEL/700MB FRONTOGENESIS...SO EXPECTING
DESPITE DRYER LOW LEVELS...THE F-GEN WILL BE STRONG ENOUGH TO
GENERATE SOME SHOWERS.
UPDATE ISSUED AT 802 AM CDT WED MAY 20 2015
UPDATED TO REMOVE FROST ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS THIS PERIOD...SMALL -SHRA CHANCES SOUTH TODAY...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD A BROAD AREA OF HIGH PRESSURE OVER THE
NORTHERN PLAINS AND UPPER MIDWEST. THE HIGH WAS BRINGING CLEAR
SKIES AND SUB-FREEZING TEMPS TO MUCH OF NORTHERN MN/WI INTO
CENTRAL WI EARLY THIS MORNING. WV IMAGERY SHOWED A RATHER VIGOROUS
LOOKING SHORTWAVE MOVING EAST ALONG THE NEB/SD BORDER. MID/HIGH
CLOUDS WITH THIS WAVE SPREADING ACROSS SOUTHERN MN/WI...HELPING
KEEP TEMPS ABOVE FREEZING. THE SHORTWAVE WAS BRINGING SOME LOWER
LEVEL MOISTURE TO IA...BUT EVEN THERE CLOUDS WERE MOSTLY ABOVE 5K-
6K FT. REGIONAL RADARS SHOWED REFLECTIVITY WITH THE SHORTWAVE FROM
SOUTH- CENTRAL SD TO NORTHERN MO BUT SFC OBS SHOW PRECIP REACHING
THE GROUND WAS MAINLY ALONG/SOUTH OF I-80 EARLY THIS MORNING.
20.00Z MODEL INITIALIZATIONS LOOK GOOD. MODELS OFFER A TIGHTER
CONSENSUS ON THE SD/NEB SHORTWAVE AS IT TRACKS EAST TODAY...AHEAD OF
BUT PARTLY PHASING WITH THE NORTHERN STREAM SHORTWAVE DROPPING INTO
EASTERN SD. TREND IS TO KEEP THE WAVES AS 2 SEPARATE PIECES OF
ENERGY QUICKLY FOLLOWING EACH OTHER THRU A MERGED TROUGH OVER THE
UPPER MIDWEST. TREND FAVORS STRONGER OF THE EARLIER MODELS AS THE
NORTHERN STREAM SHORTWAVE MOVES SOUTHEAST ACROSS THE REGION. WITH
THE TIGHT CONSENSUS OF SOLUTIONS...SHORT TERM FCST CONFIDENCE IS
GOOD THIS CYCLE.
IN THE SHORT TERM...SMALL -SHRA CHANCES ACROSS THE FAR SOUTH END OF
THE FCST AREA REMAIN A BATTLE OF 700-500MB FN/QG CONVERGENCE AND PV
ADVECTION WITH THE SHORTWAVE AND OVERCOMING DRIER NORTH TO NORTHEAST
FLOW/AIRMASS IN THE SFC-700MB PORTION OF THE COLUMN. PW VALUES IN
THE 0.5 TO 0.75 INCH RANGE ACROSS THE SOUTH END OF THE FCST AREA
TODAY BUT MAIN 850MB MOISTURE TRANSPORT STAYS WELL SOUTH IN MO AND
THE 700MB TRANSPORT MAINLY REACHES INTO THE SOUTHERN 2/3 OF IA.
MODELS...INCLUDING LOCAL/REGIONAL WRF MODELS ABOUT EVENLY SPLIT ON
-SHRA MAKING IT AS FAR NORTH AS THE KCCY/KOLZ AREAS. CONTINUED SOME
20-40 PERCENT -SHRA CHANCES ACROSS PARTS OF NORTHEAST IA INTO
EXTREME SOUTHWEST WI TODAY...PARTLY TO BLEND WITH NEIGHBORING GRIDS.
MAIN SHOT OF FORCING/LIFT MOVES ACROSS THE AREA THIS MORNING AND
CARRIED HIGHEST RAIN CHANCES AROUND 15Z...WITH RAIN CHANCES
DIMINISHING THRU THE AFTERNOON AS THE LEAD SHORTWAVE PASSES AND THE
COLUMN BEGINS TO DRY. MID/HIGH CLOUDS ACROSS THE AREA TODAY WILL
TEMPER HIGHS. 700-500MB TROUGH AXIS DROPS SOUTH OF THE AREA THIS
EVENING WITH AN INCREASE OF NORTHWEST TO NORTH FLOW AND DRIER AIR
SPREADING SOUTH ACROSS THE FCST AREA. CLOUDS LOOKING TO DECREASE
THIS EVENING WITH MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT. ANOTHER
COOL NIGHT TONIGHT UNDER MOSTLY CLEAR SKIES...A DRY LOW LEVEL
AIRMASS AND WINDS EXPECTED TO BE LIGHT. MAY YET BE SOME PATCHY FROST
ACROSS THE NORTHEAST END OF THE FCST AREA LATE TONIGHT INTO EARLY
THU MORNING. WILL LEAVE IT TO DAY CREW TO FURTHER EVALUATE THIS
AFTER THE CURRENT ADVISORY HAS EXPIRED. FAVORED A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...TEMPERATURES.
20.00Z MODELS IN GOOD AGREEMENT ON NORTHWEST FLOW ALOFT OVER THE
UPPER MIDWEST THU THRU FRI...AND REMAIN IN GOOD AGREEMENT FOR HGTS
TO RISE/RIDGING TO BUILD INTO THE REGION FRI NIGHT. MODELS ALSO WITH
RATHER GOOD RUN-TO-RUN CONSISTENCY THIS PERIOD. TREND BY FRI NIGHT
IS TOWARD STRONGER OF THE EARLIER RUNS WITH THE RIDGING OVER THE
REGION. FCST CONFIDENCE FOR THU THRU FRI NIGHT IS GOOD THIS CYCLE.
UNDER THE NORTHWEST FLOW ALOFT MODEL SOUNDINGS AND TIME-HGT X-
SECTIONS SHOWING A RATHER DRY AIRMASS/COLUMN OVER THE AREA FOR
THU THRU FRI. OTHER THAN PERHAPS SOME SCT AFTERNOON CUMULUS DURING
PEAK HEATING...THU THRU FRI SHAPING UP TO BE A CLEAR/SUNNY PERIOD.
DECENT CONSENSUS AMONG THE MODEL FOR A WEAK WAVE TO DROP ACROSS
THE WESTERN GREAT LAKES THU BUT ANY IMPACTS FROM THIS LOOKING TO
REMAIN WELL EAST OF THE FCST AREA. SFC PRESSURE GRADIENTS ON THE
WEAK SIDE FOR LIGHT WINDS...ESPECIALLY FRI WITH A SFC RIDGE AXIS
OVER THE REGION. MODEL SOUNDINGS INDICATING MIXING TO ABOUT 750MB
THU...WITH AROUND 25KTS OF WIND IN THE 850-750MB PORTION OF THE
MIXED LAYER. INCREASED WINDS/GUSTS A BIT THU AFTERNOON. COLUMN
MIXES TO AROUND 825MB FRI...WITH WINDS PROGGED TO BE LESS THAN
10KT THRU 800MB. 850MB TEMPS IN THE +7C TO +9C RANGE BOTH THU/FRI
AFTERNOONS... SUPPORTING HIGHS IN THE UPPER 60S TO NEAR 75. LIGHT
WINDS AND CLEAR SKIES FOR STRONGER RADIATIONAL COOLING THU
NIGHT...FOR A LARGER THAN NORMAL DIURNAL SWING OF TEMPERATURES. AS
PATTERN PROGRESSES FRI NIGHT...SFC-700MB TROUGHING STRENGTHENS IN
THE PLAINS. INCREASING SOUTH TO SOUTHWEST LOW LEVEL FLOW STARTS TO
SPREAD MOISTURE/WARMING NORTHEAST INTO THE UPPER MIDWEST...ALONG
WITH HIGHER LEVEL MOISTURE AHEAD OF THE WESTERN CONUS TROUGHING
SPILLING THRU THE RIDGING AND INTO THE REGION. TREND OF WARMER
LOWS AND SOME INCREASE OF CLOUDS FRI NIGHT LOOKS GOOD. TRENDED
TOWARD WARMER OF GUIDANCE HIGHS THU/FRI...THEN FAVORED A BLEND OF
THE GUIDANCE LOWS THU/FRI NIGHTS.
FOR SATURDAY THRU TUESDAY...DAYS 4 TO 7...
MEDIUM RANGE MODEL RUNS OF 20.00Z IN QUITE GOOD AGREEMENT SAT/SUN
SHOWING THE MID LEVEL RIDGE AXIS TO SLOWLY MOVE EAST OF THE REGION
AND DEEP SOUTHWEST FLOW ALOFT OVER MUCH OF THE UPPER MIDWEST BY LATE
SUN. DIFFERENCES BEGIN TO APPEAR BY SUN NIGHT/MON...ON THE TIMING/
STRENGTH DETAILS OF SHORTWAVE ENERGY EJECTING OUT OF THE WESTERN
CONUS TROUGH AND TOWARD/INTO THE UPPER MIDWEST. DETAIL DIFFERENCES
CONTINUE TUE...BUT GENERAL LONGWAVE CONSENSUS FOR BROAD TROUGHING
OVER MUCH OF THE CENTRAL/WESTERN CONUS. WITH THIS TRENDING TO BE A
MORE UNSETTLED WEATHER PERIOD AND SENSIBLE WEATHER ANY ONE DAY
STRONGLY IMPACTED BY THE SHORTWAVE/MESO-SCALE DETAILS...FCST
CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE THIS CYCLE.
MODEL CONSENSUS HAS SOUTHERLY FLOW AND MOISTURE CONTINUING TO
INCREASE INTO THE UPPER MIDWEST SATURDAY THRU SUN. PW VALUES PROGGED
IN THE 1.5 INCH RANGE OVER MUCH OF THE FCST AREA BY 12Z SUN. THIS
WITH A BROAD INCREASE OF LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT AND
INSTABILITY. MODEL CONSENSUS OF INCREASING SHRA/TSRA CHANCES FROM
WEST TO EAST ACROSS THE AREA FROM SAT THRU SUN NIGHT LOOKING WELL
TRENDED...THOUGH THE SPECIFIC DETAILS OF PERIOD HAVE YET TO BE
SORTED OUT. WITH SLOW PROGRESSION OF THE LONGWAVE PATTERN...AND
ADDITIONAL SHORTWAVES TO COME THRU LONGWAVE TROUGHING THAT IS
PROGGED TO REMAIN OVER THE WEST HALF OF THE CONUS...THE MODEL/
ENSEMBLE CONSENSUS SHRA/ TSRA CHANCES CONTINUING THRU MON/TUE ARE
REASONABLE FOR NOW. GIVEN UNCERTAINTIES WITH SHRA/TSRA CHANCES/
TIMING/COVERAGE /AND CLOUD COVER/ ANY ONE DAY...DID NOT DEVIATE
FROM THE MODEL CONSENSUS HIGHS/LOWS FOR SAT THRU TUE. IF ANY ONE
OR MORE OF DAYS 4 TO 7 END UP DRY AND SUNNIER THAN CURRENTLY
EXPECTED... HIGHS THAT DAY COULD EASILY BE 5F TO 10F WARMER THAN
THOSE IN THE FCST GRIDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 638 AM CDT WED MAY 20 2015
MID CLOUDS...ASSOCIATED WITH A LOW PRESSURE SYSTEM MOVING THROUGH
THE SOUTHERN MISSOURI...WILL REMAIN OVER BOTH TAF SITES THROUGH
THIS EVENING...AND THEN SKIES WILL CLEAR. LIGHT WINDS WILL
GRADUALLY VEER FROM THE NORTH THIS MORNING TO SOUTH AND SOUTHWEST
BY THIS AFTERNOON AND REMAIN THAT WAY THROUGH TONIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
333 PM MDT WED MAY 20 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 243 PM MDT WED MAY 20 2015
SFC ANALYSIS SHOWS THE HIGH PRESSURE CENTER LOCATED NEAR THE PINE
RIDGE WITH EAST TO NORTHEAST UPSLOPE AND PERSISTENT LOW CLOUDS
ACROSS THE REGION. IT HAS BEEN ANOTHER COOL DAY WITH TEMPS A GOOD
20 DEGREES BELOW NORMAL. EXPIRED THE DENSE FOG ADVISORY FOR THE
SOUTH LARAMIE RANGE WITH WYDOT OBS SHOWING MOST VIS ABOVE 1 MILE.
THE HRRR DOES INDICATE VIS DROPPING BELOW ONE HALF MILE OVER THE
SOUTH LARAMIE RANGE BY 03Z. THIS MAKES SENSE WITH SFC WINDS
REMAINING SOUTHEAST TO SOUTH OVERNIGHT. HAVE AREAS OF FOG FROM
BUFORD TO THE SUMMIT BY EARLY TONIGHT AND CONTINUING THROUGH
THURSDAY MORING. WILL LET THE EVENING/NIGHT SHIFT MONITOR THE OBS
AND WEBCAMS OVER THE SUMMIT...AS DENSE FOG IS DEFINITELY POSSIBLE IN
THIS PATTERN. SHOWERS DEVELOPING THIS AFTN ALONG AND WEST OF THE
LARAMIE RANGE HAVE BEEN STRUGGLING TO STAY TOGETHER IN THE VERY
STABLE AIRMASS OVER THE PLAINS. KEPT ISOLATED TO SCATTERED SHOWERS
CONFINED TO MAINLY THE LARAMIE RANGE AND POINTS WEST THROUGH THE
EVENING.
PATTERN DOES NOT CHANGE A WHOLE LOT BY THURSDAY. LOW CLOUDS WILL BE
STUBBORN TO CLEAR YET AGAIN WITH MOIST SOUTHEAST LLVL FLOW.
SLIGHTLY BETTER INSTABILITY WILL EXIST ALONG THE LARAMIE RANGE (CAPE
VALUES OF 100-200 J/KG) BUT THIS IS LARGELY DEPENDENT ON SOME AFTN
CLEARING...WHICH IS QUESTIONABLE. INSTABILITY REALLY DROPS OFF TO
THE EAST OF CHEYENNE SO EXPECTING STORMS TO REMAIN CONFINED IN
VICINITY OF THE LARAMIE RANGE. A SHORTWAVE WILL EJECT NORTHWARD
FROM COLORADO BY LATE THURS NIGHT AND FRI MORNING. WITH GOOD UPPER
LEVEL DIFLUENCE...MODELS HAVE BEEN CONSISTENT AT SHOWING WIDESPREAD
RAIN DEVELOPING OVER THE PLAINS BY FRI MORNING AND CONTINUING
THROUGH MUCH OF THE DAY. THIS IS LOOKING LIKE ANOTHER 0.25-0.75
INCH MAINLY STRATIFORM RAIN EVENT FOR LOCATIONS TO THE EAST OF THE
LARAMIE RANGE. DID LOWER HIGHS A FEW DEGREES ON FRI WITH HIGHS
STRUGGLING TO GET ABOVE THE MID 50S.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 243 PM MDT WED MAY 20 2015
THE MAIN CONCERN WITH THIS PORTION OF THE FORECAST IS THE SEVERE
WEATHER POTENTIAL SATURDAY.
SATURDAY-SATURDAY NIGHT:
LATEST LOOK AT THE GEM/GEFS ENSEMBLES AND ECMWF ARE SHOWING
REALLY GOOD AGREEMENT IN THE TRACK OF THE UPPER LEVEL TROF THIS
WEEKEND. THE MODELS ARE ALSO IN AGREEMENT IN SHOWING THIS CLOSED
UPPER TROF OPENING UP IN NORTHWEST COLORADO AND SENDING ITS FIRST
PIECE OF ENERGY INTO OUR REGION SATURDAY. HOWEVER...THERE IS QUITE
A BIT OF STANDARD DEVIATION IN THE PLACEMENT OF THE SURFACE LOW
AROUND 00Z SUNDAY. THE MEAN ENSEMBLES ARE SHOWING THE SURFACE LOW
DEVELOPING IN EASTERN COLORADO. HOWEVER...THERE IS SOME HINTS THAT
THIS SURFACE LOW MAY ACTUALLY DEVELOP FURTHER NORTH IN NORTHEAST
COLORADO AND LIFT NORTHEAST THROUGH THE NEBRASKA PANHANDLE. IF
THIS SURFACE LOW DEVELOPS FURTHER NORTH...WE MAY SEE WARMER
TEMPERATURES AND HIGHER LOW LEVEL MOISTURE BEING DRAWN INTO AREAS
EAST OF THE LARAMIE WHICH WILL RESULT IN HIGHER INSTABILITY. THIS
COULD SET THE STAGE FOR SEVERE WEATHER IN AREAS EAST OF THE
LARAMIE RANGE SATURDAY AFTN/EVE...ESPECIALLY WITH 0-6KM SHEAR
VALUES APPROACHING 40 TO 50 KTS. ANOTHER CONCERN IS WHETHER OR NOT
WE WILL SEE LOW CLOUDS. AT THIS POINT...IT DOES NOT APPEAR THAT
THE LOW CLOUDS WILL BE PRESENT...BUT WE WILL HAVE TO SEE HOW THAT
EVOLVES. IF THE LOW CLOUDS ARE NOT PRESENT...TEMPERATURES SHOULD
BE ABLE TO CLIMB TO THE 60S.
SUNDAY-SUNDAY NIGHT:
THE MODELS ARE SHOWING THE MAIN UPPER LEVEL TROF MOVING INTO THE
AREA ON SUNDAY IN ITS WEAKENED STATE. THERE IS A LITTLE MORE
UNCERTAINTY ON HOW THIS TROF WILL IMPACT THE AREA ON SUNDAY
AFTERNOON INTO SUNDAY EVENING. AT THIS POINT...IT APPEARS LIKE THE
MAIN CONVECTION SHOW WILL BE ON SATURDAY AFTERNOON/EVENING.
HOWEVER...IF WE DO NOT SEE MANY STORMS DURING THAT TIME...THEN
SUNDAY MAY BE A DAY TO WATCH AS WELL. IF WE DO SEE WIDESPREAD
CONVECTION ON SATURDAY THEN SUNDAY CHANCES MAY BE MUCH SMALLER.
FOR NOW...WE WILL STAY WITH THE MODEL BLENDS FOR CONSISTENCY SAKE.
MONDAY-WEDNESDAY:
MODELS/ENSEMBLES ARE IN PRETTY GOOD AGREEMENT IN SHOWING THE UPPER
LEVEL RIDGE BUILDING OVER THE AREA AHEAD OF THE NEXT UPPER LEVEL
TROF MOVING INTO THE NORTHERN ROCKIES. THIS TROF WILL INDUCE UPPER
LEVEL DIFFLUENCE OVER THE AREA ON MONDAY AND TUESDAY WHICH COULD
SPARK SOME CONVECTION OVER THE MOUNTAINS WITH SOME OF THIS
CONVECTION POSSIBLY SPILLING OVER INTO THE PLAINS. OVERALL...IT
DOES NOT LOOK LIKE A REAL WET PATTERN...BUT WE CANNOT RULE OUT THE
AFTERNOON AND EVENING CONVECTION CHANCES OVER OUR AREA EITHER.
ALTHOUGH...TEMPERATURES WILL NOT BE TOO COOL WITH HIGHS CLIMBING
TO NEAR NORMAL READING WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1059 AM MDT WED MAY 20 2015
THE MAIN CONCERN WITH THIS TAF ISSUANCE IS THE TIMING OF WHEN THE
IFR/MVFR CEILINGS WILL BEGIN TO CLEAR OUT.
LATEST SURFACE ANALYSIS WAS SHOWING COLD AIR DAMMING PERSISTING ALONG
THE LEE SIDE OF THE LARAMIE RANGE AROUND LUNCHTIME. THE MODELS ARE
CURRENTLY TOO FAST IN MOVING THIS CANADIAN SURFACE HIGH EAST THIS
AFTERNOON. AS A RESULT...WE ARE EXPECTING THE LOW CEILINGS TO
HANG ON TO MUCH OF THE AREA THIS AFTERNOON. THE LOWEST CEILINGS
ARE AROUND CYS (AROUND 800FT) AND POINTS WEST TO THE I-80 SUMMIT
WHERE THEY ARE STILL EXPERIENCING DENSE FOG. THIS SURFACE HIGH
SHOULD GRADUALLY SHIFT EAST LATE THIS AFTERNOON INTO THIS EVENING.
HOWEVER...WE ARE NOT CONFIDENT THAT CYS CEILINGS WILL CLIMB VERY
MUCH DUE TO THE EASTERLY FLOW KICKING IN. WE ARE LITTLE MORE
CONFIDENT THAT THE LOWER CEILINGS SHOULD BEGIN TO SCOUR OUT FROM
NORTH TO SOUTH ACROSS THE PANHANDLE SITES LATE THIS AFTERNOON
BASED ON THE LATEST SATELLITE TRENDS. HOWEVER...THERE IS A
POSSIBILITY THAT SOME PATCHY FOG COULD DEVELOP IN ITS WAKE.
OTHERWISE...WEAK ISENTROPIC ASCENT WILL BRING SOME VFR CEILINGS
INTO THE AREA AFTER MIDNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 243 PM MDT WED MAY 20 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TEMPERATURES WILL
REMAIN BELOW NORMAL AND AFTERNOON HUMIDITY VALUES WILL BE ABOVE 50
PERCENT. THE BEST CHANCE OF WIDESPREAD WETTING RAIN WILL COME
THURSDAY NIGHT AND FRIDAY.
&&
.HYDROLOGY...
ISSUED AT 243 PM MDT WED MAY 20 2015
LARAMIE RIVER AT FORT LARAMIE AND LARAMIE WILL CONTINUE TO RUN AT
RELATIVELY HIGH LEVELS THROUGH THIS WEEK...BUT AT THIS TIME IS
EXPECTED TO REMAIN WITHIN ITS BANKS. ANOTHER ROUND OF MODERATE TO
HEAVY RAINFALL IS EXPECTED OVER THE HIGH PLAINS AND POSSIBLY THE
LARAMIE VALLEY ON FRIDAY...SO WILL NEED TO CONTINUE TO MONITOR
THE LARAMIE RIVER THROUGH LATE THIS WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...REC
AVIATION...REC
FIRE WEATHER...ZF
HYDROLOGY...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1155 AM MDT WED MAY 20 2015
.UPDATE...
ISSUED AT 1059 AM MDT WED MAY 20 2015
LOWERED HIGHS FOR TODAY MAINLY FROM LARAMIE TO CHEYENNE AS LOW
CLOUDS WILL BE QUITE PERSISTENT INTO THE AFTERNOON. THE HRRR DOES
SHOW VIS IMPROVING OVER THE SOUTHERN LARAMIE RANGE AND THE
ARLINGTON AREA AFTER 18Z...AND WYDOT VIS IS SLOWLY STARTING TO
COME UP. DENSE FOG ADVISORY WILL PROBABLY BE EXPIRED AT NOON...BUT
WILL MONITOR OVER THE NEXT HOUR. WITH A STABLE AIRMASS OVER THE
PLAINS...SHOWERS AND AN ISOLATED TSTM WILL MAINLY BE CONFINED TO
THE SNOWY RANGE WESTWARD.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 346 AM MDT WED MAY 20 2015
THE PACIFIC STORM SYSTEM WHICH BROUGHT RAIN AND EVEN SOME SNOW TO
THE REGION YESTERDAY IS CURRENTLY WEAKENING AND MOVING EASTWARD
OVER THE NORTHERN PLAINS THIS MORNING. THERE IS STILL SOME LIGHT
SNOW BEING REPORTED ACROSS PORTIONS OF FAR EASTERN WYOMING AND
WESTERN NEBRASKA...BUT ACCUMULATIONS HAVE BEEN MINIMAL. OF MORE
SIGNIFICANCE IS THE FREEZING DRIZZLE NEAR THE RIDGE TOPS AND ALONG
THE LARAMIE RANGE...WITH CHEYENNE REPORTING FREEZING DRIZZLE
THROUGH MOST OF THE NIGHT. THERE HAVE BEEN A FEW REPORTS OF BLACK
ICE ON THE ROADWAYS...BUT SO FAR IT HAS BEEN RELATIVELY ISOLATED
WITH MAINLY JUST WET ROADWAYS. WILL CONTINUE TO KEEP AN EYE ON
THIS AS TEMPERATURES CONTINUE TO LOWER THROUGH THE UPPER 20S EARLY
THIS MORNING. HIGH TEMPERATURES TODAY WILL STRUGGLE TO REACH THE
MID TO UPPER 40S DUE TO A PERSISTENT LOW CLOUD DECK AND EVEN SOME
PATCHY FOG/DRIZZLE ALONG THE SOUTH FACING RIDGES.
EVENTUALLY...WINDS WILL SHIFT INTO THE EAST TO NORTHEAST TODAY
WITH CLOUD CEILINGS INCREASING A BIT BY THE AFTERNOON. NOT MUCH
SUN TODAY...WITH VALLEY LOCATIONS WEST OF THE LARAMIE RANGE HAVING
THE BEST CHANCE TO SEE SOME SUNSHINE. WITH SO MUCH MOISTURE AND
NEARLY SATURATED LOW TO MIDLEVELS...IT WILL NOT TAKE MUCH
INSTABILITY TO GENERATE SOME LIGHT SHOWERS. KEPT POP BETWEEN 20 TO
40 PERCENT FOR NOW...WITH SHOWERS LIKELY IN THE MOUNTAINS.
TONIGHT WILL BE MORE OF THE SAME...BUT WITH LESS CLOUD COVER OVER
THE NORTHERN AND WESTERN PORTION OF THE FORECAST AREA. MODELS SHOW
WINDS SHIFTING BACK INTO THE SOUTH OR SOUTHEAST...RESULTING IN
ANOTHER ROUND OF FOG AND/OR DRIZZLE FOR THE CHEYENNE AND PINE
RIDGE...ALONG WITH THE EASTERN FOOTHILLS OF THE LARAMIE RANGE. DO
NOT EXPECT THIS STRATUS DECK TO MAKE IT WEST OF THE LARAMIE
RANGE...SO LARAMIE AND RAWLINS MAY JUST BE PARTLY CLOUDY TONIGHT
BUT RELATIVELY COLD. MAY NEED A FROST OR FREEZE ADVISORY FOR
PORTIONS OF THE NORTHERN NEBRASKA PANHANDLE AS LOW TEMPERATURES
ARE PROGGED TO BE NEAR OR JUST BELOW FREEZING AT CHADRON AND
ALLIANCE...WHICH IS OVER ONE WEEK PAST THE AVERAGE LAST FREEZE.
IT IS UNCLEAR HOW MUCH CLOUDINESS WILL BE PRESENT IN THESE
AREAS...SO WILL HOLD OFF ON ANY HEADLINES FOR NOW.
WARMER TEMPERATURES ARE EXPECTED ON THURSDAY AS A SHORT WAVE
RIDGES MOVES ACROSS THE AREA. TEMPERATURES WILL STILL BE BELOW
NORMAL THOUGH AND GENERALLY IN THE MID 50S TO LOW 60S. THERE
SHOULD BE A BREAK IN THE PRECIPITATION ACROSS THE AREA DUE TO THE
MIDLEVEL SUBSIDENCE ASSOCIATED WITH THE RIDGE ALOFT. THE BREAK IN
THE PRECIPITATION WILL BE SHORT LIVED HOWEVER...AS ALL MODELS
INDICATE ANOTHER PACIFIC STORM SYSTEM MOVING TOWARDS THE AREA.
INITIALLY...EXPECT A ROUND OF SCATTERED SHOWERS AND ISOLATED TSTORMS
LATE ON THURSDAY AND INTO THURSDAY EVENING. WILL HAVE TO WATCH THE
NEXT SIGNIFICANT SHORTWAVE TROUGH LIFTING NORTHEAST OUT OF THE
SOUTHWEST LATE THURSDAY AND INTO FRIDAY. MODELS SHOW THIS
SHORTWAVE MOVING ACROSS COLORADO AND WYOMING EARLY ON FRIDAY
BRINGING ANOTHER ROUND OF RAINFALL AND MOUNTAIN SNOWS DUE TO A
LARGE AREA OF UPPER LEVEL DIFFLUENCE. SNOWLEVELS SHOULD BE
BETWEEN 7500 TO 8500 FEET THIS TIME AROUND...SO DO NOT EXPECT ANY
SNOW FLAKES OVER THE HIGH PLAINS AT THIS TIME. THIS SYSTEM HAS A
BETTER CHANCE TO CONTAIN HEAVIER RAIN SHOWERS COMPARED TO
YESTERDAYS SYSTEM...MAINLY BECAUSE OF THE CONDITIONAL INSTABILITY
ALOFT SHOWN BY MODEL SOUNDINGS. AFTER THE MAIN AREA OF
PRECIPITATION...EXPECT PARTIAL CLEARING SKIES FRIDAY AFTERNOON.
WITH THE COLD POOL ALOFT ASSOCIATED WITH THE UPPER LEVEL TROUGH
OVERHEAD...IT WILL NOT TAKE MUCH TO TRIGGER SCATTERED SHOWERS AND
TSTORMS LATE IN THE AFTERNOON EVEN AFTER THE TROUGH MOVES
NORTHWARD...WHICH IS TYPICAL THIS TIME OF THE YEAR. CONTINUED
INCREASING POP BETWEEN 60 TO 80 PERCENT...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 340 AM MDT WED MAY 20 2015
ACTIVITY WEATHER PATTERN TO REMAIN IN PLACE THROUGH THE LONG TERM
FORECAST PERIOD. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL EXIST
EVERY DAY AS COOL UNSTABLE AIR ALOFT REMAINS IN PLACE ALONG WITH
SEVERAL DISTURBANCES WHICH WILL MOVE ACROSS THE FORECAST AREA
INTO EARLY NEXT WEEK. DIFFICULT TO PINPOINT THE BEST CHANCES FOR
PRECIPITATION GIVEN THE FACT IT IS TOUGH FOR THE MODELS TO RESOLVE
A NEARLY CONTINUOUS STREAM OF UPPER DISTURBANCES...BUT SAFE TO
SAY AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE COMMON DUE TO
DIURNAL HEATING PRODUCING INSTABILITY MANY DAYS. NOT OVERLY
CONCERNED ABOUT SEVERE THUNDERSTORMS THROUGH THE PERIOD BUT IF
THERE IS A DAY TO WATCH IT IS SATURDAY. AT THIS TIME IT LOOKS AT
THROUGH THE BOUNDARY LAYER MAY STAY CAPPED WHILE A DISTURBANCE
MOVES ACROSS THE AREA EARLY IN THE DAY...BUT ELEVATED CONVECTION
MAY BE POSSIBLE TOO. SOMETHING TO KEEP AN EYE ON THE NEXT FEW
DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1059 AM MDT WED MAY 20 2015
THE MAIN CONCERN WITH THIS TAF ISSUANCE IS THE TIMING OF WHEN THE
IFR/MVFR CEILINGS WILL BEGIN TO CLEAR OUT.
LATEST SURFACE ANALYSIS WAS SHOWING COLD AIR DAMMING PERSISTING ALONG
THE LEE SIDE OF THE LARAMIE RANGE AROUND LUNCHTIME. THE MODELS ARE
CURRENTLY TOO FAST IN MOVING THIS CANADIAN SURFACE HIGH EAST THIS
AFTERNOON. AS A RESULT...WE ARE EXPECTING THE LOW CEILINGS TO
HANG ON TO MUCH OF THE AREA THIS AFTERNOON. THE LOWEST CEILINGS
ARE AROUND CYS (AROUND 800FT) AND POINTS WEST TO THE I-80 SUMMIT
WHERE THEY ARE STILL EXPERIENCING DENSE FOG. THIS SURFACE HIGH
SHOULD GRADUALLY SHIFT EAST LATE THIS AFTERNOON INTO THIS EVENING.
HOWEVER...WE ARE NOT CONFIDENT THAT CYS CEILINGS WILL CLIMB VERY
MUCH DUE TO THE EASTERLY FLOW KICKING IN. WE ARE LITTLE MORE
CONFIDENT THAT THE LOWER CEILINGS SHOULD BEGIN TO SCOUR OUT FROM
NORTH TO SOUTH ACROSS THE PANHANDLE SITES LATE THIS AFTERNOON
BASED ON THE LATEST SATELLITE TRENDS. HOWEVER...THERE IS A
POSSIBILITY THAT SOME PATCHY FOG COULD DEVELOP IN ITS WAKE.
OTHERWISE...WEAK ISENTROPIC ASCENT WILL BRING SOME VFR CEILINGS
INTO THE AREA AFTER MIDNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 246 AM MDT WED MAY 20 2015
NO FIRE WEATHER CONCERNS THIS WEEK DUE TO UNSEASONABLY
COOL TEMPERATURES AND HIGH CHANCES OF PRECIPITATION. EVEN SOME SNOW
IS EXPECTED OVER THE MOUNTAINS EARLY TODAY AND ON FRIDAY. DAYTIME
RELATIVE HUMIDITIES ACROSS THE HIGH VALLEYS AND HIGH PLAINS WILL
LIKELY NOT LOWER BELOW 50 PERCENT UNTIL EARLY NEXT WEEK.
&&
.HYDROLOGY...
ISSUED AT 246 AM MDT WED MAY 20 2015
LARAMIE RIVER AT FORT LARAMIE WILL CONTINUE TO RUN AT RELATIVELY
HIGH LEVELS THROUGH THIS WEEK...BUT AT THIS TIME IS EXPECTED TO
REMAIN WITHIN ITS BANKS. THE PACIFIC STORM SYSTEM WHICH PUSHED
ACROSS THE REGION YESTERDAY DID NOT IMPACT RIVER LEVELS TOO MUCH
ACROSS THE AREA. HOWEVER...ANOTHER PACIFIC SYSTEM ON FRIDAY MAY
BRING MODERATE TO HEAVY RAINFALL AMOUNTS TO THE HIGH PLAINS AND
POSSIBLY THE LARAMIE VALLEY...SO WILL NEED TO CONTINUE TO MONITOR
THE LARAMIE RIVER THROUGH LATE THIS WEEK. THE LARAMIE RIVER AT
LARAMIE IS FORECAST TO FALL BELOW ACTION STAGE THIS WEEKEND OR
EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL NOON MDT TODAY FOR WYZ110-116.
NE...NONE.
&&
$$
UPDATE...ZF
SHORT TERM...TJT
LONG TERM...SML
AVIATION...REC
FIRE WEATHER...TJT
HYDROLOGY...TJT
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
1013 PM PDT Thu May 21 2015
.Synopsis...
Mild weather with mountain showers and thunderstorms will continue
through Friday. Warmer temperatures with fewer mountain showers
expected this weekend into next week.
&&
.Discussion...
Mountain showers and thunderstorms have all dissipated this
evening. Skies are partly cloudy over the area with a moderate
onshore flow and winds gusting to 20 mph delta to srn sac/nrn sj
valleys. Short term models indicate showers to rotate back over
the Sierra from Nevada after midnight will keep shower chances
going. Likely to see another layer of status cloudiness towards
morning srn/sac valley. Current forecast is on track no update
needed.
.Previous Discussion...
A broad upper level trough remains quasi-stationary along the
West Coast, with blocking ridge situated over the Rockies. Several
shortwaves have been rotating through this upper trough, and the
current one is moving toward the California coast today.
Widespread showers and thunderstorms have once again developed
this afternoon across the interior mountains of Northern
California once again. Lightning networks haven`t detected quite as
much lightning as yesterday, but today`s showers do seem to be
producing more in the way of precipitation. We`ve also seen a few
reports of snow above 8000 ft or so along the high Sierra. With
southeast to easterly flow aloft, some showers may try to work
their way down the hill toward the Valley this evening into Friday
morning. The ARW, NMM, and HRRR all hint at this possibility.
The aforementioned shortwave pushes south toward Southern
California on Friday, with steering flow becoming more northerly.
While we should still expect some mountain showers and
thunderstorms Friday afternoon, they shouldn`t be as widespread.
Northerly flow aloft will continue over Northern California
through the weekend. This should promote warmer weather, with
temperatures closer to normal. Isolated showers will still be
possible over the mountains, but confined to primarily Lake Tahoe
and southward.
Dang
&&
.Extended Discussion (Monday through Thursday)
For the extended period, the ability of the general upper trough
pattern over the region to persist through the rest of May is
impressive. with no significant heat-ups in sight. Upper low
pressure systems with weak short waves will pass through at times.
Unlike the current system, most of the lows will be centered to the
north and east of the forecast area. Most of the instability will
linger over the mountains, with afternoon heating bringing some
thunderstorms. The Valley should remain generally dry.
Temperatures will gradually warm to near to slightly above normal
levels by mid week on. Daytime highs in the valley will generally
be in the low to mid 80s with 70s in Delta Breeze influenced areas
(upper 60s for the Vallejo/Benicia area). Mountain highs will
range in the 50s/60s while Foothills warm into the 70s. EK
&&
.Aviation...
General VFR conditions expected for tonight. Could see some
bkn020-025 cigs for the Delta and into the southern Sacramento
Valley 12-18z Friday morning. The Delta could see gusts to 30kt
tonight.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
159 AM EDT FRI MAY 22 2015
.SYNOPSIS...
FAST-MOVING LOW PRESSURE WILL BRING A PERIOD OF LIGHT RAIN TO
RHODE ISLAND AND SOUTHEAST MASSACHUSETTS THIS MORNING. THEN A
COLD FRONT MAY TRIGGER AN ISOLATED SHOWER LATE THIS AFTERNOON
AND EARLY EVENING. BEHIND THIS FRONT...FROST AND MAYBE EVEN
RECORD- BREAKING COLD...IS POSSIBLE FRIDAY NIGHT INTO SATURDAY
MORNING. HIGH PRESSURE WILL BRING ABOUT DRY WEATHER SUNDAY BUT A
PERIOD OF WET WEATHER MAY RETURN LATER MONDAY/MONDAY NIGHT.
WARMER BUT MORE UNSETTLED WEATHER IS EXPECTED NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
2 AM UPDATE...
MID LEVEL FGEN RAIN BAND COMING ACROSS LI/LI SOUND...COASTAL CT
AND RI AT 2 AM...LIFTING NE AND WILL TRACK INTO INTERIOR RI AND
SOUTHEAST MA...PROBABLY STAYING SOUTH OF BOSTON. STEADIEST RAINS
WILL BE FOCUSED OVER CAPE COD AND THE ISLANDS THRU 12Z. PREVIOUS
FORECAST CAPTURES THESE DETAILS NICELY SO NO MAJOR CHANGES WITH
THIS UPDATE. EARLIER DISCUSSION BELOW.
================================================================
DESPITE RADAR RETURNS OVER BID/MVY AND ACK LOW LEVEL DRY AIR AS
SEEN ON THE 00Z OKX SOUNDING CONTINUES TO EVAPORATE ANY RAINFALL
BEFORE REACHING THE SURFACE ACROSS THIS AREA. EVENTUALLY BOUNDARY
LAYER WILL SATURATE AND RAIN WILL REACH THE GROUND ALONG THE SOUTH
COAST INCLUDING CAPE COD AND THE ISLANDS THE SECOND HALF OF THE
NIGHT INTO EARLY FRI MORNING.
AS FOR MODEL GUIDANCE...12Z ECMWF/18Z RUNS OF GFS AND NAM/21Z SREF
AND 12Z NMM AND ARW ALL BRING NORTHWEST PORTION OF RAIN SHIELD
INTO THE BOSTON-PROVIDENCE 06Z-12Z...ALBEIT VERY LIGHT RAIN WITH
STEADIER RAIN CONFINED TO IMMEDIATE SOUTH COAST INCLUDING CAPE COD
AND ISLANDS. AT 00Z RADAR AND SATELLITE TRENDS SUPPORT THIS
SCENARIO. LATEST RUNS OF THE HRRR AND RAP ARE FARTHER SOUTHEAST.
NONETHELESS CURRENT FORECAST CAPTURES THIS THEME WITH BULK OF RAIN
ALONG THE SOUTH COAST WITH MUCH LIGHTER RAIN NORTHWARD INTO
PROVIDENCE- BOSTON CORRIDOR. ALL OTHER FORECAST PARAMETERS ON
TRACK AS WELL...THUS LITTLE IF ANY CHANGES WITH THIS FORECAST
UPDATE. EARLIER DISCUSSION BELOW.
==================================================================
TONIGHT...
NOT MUCH CHANGE FROM PREVIOUS THINKING. NORTHERN STREAM SHORTWAVE
ENERGY WILL ARRIVE LATER TONIGHT. THIS FEATURE WILL SPAWN A LATE
SEASON COASTAL LOW WAVE OVER THE SOUTHEAST STATES...THAT WILL
TRACK NEAR OR JUST SOUTHEAST OF THE 40N/70W BENCHMARK BY FRIDAY
MORNING.
21/12Z GUIDANCE CONTINUES ITS EXCELLENT AGREEMENT ON STEADY
RAINFALL WORKING INTO SOUTHEAST MA AND PORTIONS OF RI OVERNIGHT.
THERE IS STILL SOME QUESTION HOW FAR WEST THE BACK EDGE OF THE
PRECIPITATION SHIELD WILL MAKE IT. THE 09Z SREF IS THE FARTHEST
WEST...WITH THE 12Z NAM THE FARTHEST EAST. STAYED WITH A MORE
MODERATE APPROACH...AS EVIDENCED BY THE GFS AND ECMWF SOLUTIONS.
SINCE THIS WILL BE A DEVELOPING COASTAL LOW...TIMING OF THE
DYNAMIC COMPONENTS COMING TOGETHER WILL BE CRUCIAL. WILL NEED TO
WATCH THIS ASPECT OF THIS STORM CLOSELY.
REGARDING CONVECTIVE POTENTIAL...MODEL SOUNDINGS ARE NOT FAVORABLE
FOR ANY SORT OF CONVECTION OVERNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
FRIDAY...
A 3-PART DAY WITH MORNING RAINS LIKELY OVER RI AND SOUTHEAST
MA...POSSIBLY NORTHWARD TO BOSTON. DRIER WEATHER...ALONG WITH
MORE SUNSHINE...BRIEFLY DEVELOPS MID TO LATE MORNING AS COASTAL
LOW PRESSURE MOVES FARTHER OFFSHORE.
ANOTHER MID-LEVEL SHORTWAVE IS STILL EXPECTED TO MOVE THROUGH
SOUTHERN NEW ENGLAND FRIDAY AFTERNOON. COMBINED WITH AN
APPROACHING COLD FRONT...THERE SHOULD BE ENOUGH OF A TRIGGER TO
GENERATE SCATTERED SHOWERS ACROSS SOUTHERN NEW ENGLAND...MAINLY
ACROSS EASTERN MA. UNSEASONABLY STRONG COLD POOL ALOFT WILL ALSO
MEAN FAIRLY STEEP LAPSE RATES. THE BIG QUESTION WHICH REMAINS TO
BE ANSWERED WILL BE THE AMOUNT OF AVAILABLE MOISTURE. JUST ABOUT
ALL OF THE GUIDANCE REMAINS VERY DRY ABOVE 10 KFT. THUS CANNOT
COMPLETELY RULE OUT THE POSSIBILITY OF ISOLATED THUNDERSTORMS.
SHOULD ANY THUNDERSTORMS DEVELOP...SMALL HAIL WOULD BE A RISK IN
THE STRONGER CELLS.
FRIDAY NIGHT...
CONFIDENT WITH THE COLD FRONT PUSHING OFFSHORE THAT COLD AIR
ADVECTION WILL BE IN FULL SWING INTO SATURDAY MORNING. PROBABLY
LOOKING AT TEMPERATURES COLD ENOUGH TO WARRANT FROST ADVISORIES
ACROSS PORTIONS OF WESTERN MA...AGAIN. AS PREVIOUSLY MENTIONED...
THERE IS STILL AN ISSUE WITH WINDS. STILL EXPECTING A STEADY
NORTHWEST WIND...WHICH WOULD BE ENOUGH TO KEEP THE SURFACE LAYER
MIXED...AND PRECLUDE WIDESPREAD FROST DEVELOPMENT. WILL NEED TO
KEEP AN EYE ON THIS POTENTIAL. WILL BE CLOSE TO RECORD LOWS FOR A
FEW LOCATIONS /SEE THE CLIMATE SECTION BELOW/.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- UNSEASONABLY COOL SATURDAY
- FROST / FREEZE HEADLINES LIKELY FOR SATURDAY MORNING
- SEASONABLE AND DRY FOR SUNDAY
- BEGINNING MEMORIAL DAY...A WET-WEATHER PATTERN BEGINS TO EMERGE
- COULD REMAIN SEASONABLE AND WET THROUGH THE REMAINDER OF THE WEEK
*/ DISCUSSION...
CONFIDENT WITH THE COLD FRONT PUSHING OFFSHORE FRIDAY NIGHT THAT
COLD AIR ADVECTION WILL BE IN FULL SWING INTO SATURDAY MORNING.
BREEZY NW FLOW REARWARD OF THE PIVOTING VORTEX THRU N NEW ENGLAND
WILL USHER AN ANOMALOUSLY COLD AIRMASS S ALOFT. EXPECT WIDESPREAD
FROST/FREEZE HEADLINES ACROSS THE INTERIOR WITH THE BIGGEST IMPACT
OVER N/W PORTIONS OF MA. BUT AGREE WITH PREVIOUS FORECASTER THINKING
THAT THE BREEZY NW-FLOW COULD MITIGATE FROST DEVELOPMENT DESPITE
COLD TEMPERATURES. WILL BE CLOSE TO RECORD LOWS /SEE THE CLIMATE
SECTION BELOW/. COLD AIRMASS LINGERS AS HIGH PRESSURE BUILDS S OF
NEW ENGLAND. COOL AND DRY FOR SATURDAY. MORE SEASONABLE SUNDAY WITH
RETURN S-FLOW.
BEGINNING MEMORIAL DAY AM LESS CONFIDENT WITH THE FORECAST. PACIFIC-
ORIGIN IMPULSES ROTATING THROUGH THE W-HALF OF THE CONUS INVOKE DOWN-
STREAM RIDGING INTO NEW ENGLAND. BERMUDA HIGH REAFFIRMS ROUND THE W-
PERIPHERY WHICH SW-FLOW PREVAILS. THE WARM-FRONTAL LEADING EDGE OF
WARM-MOIST AIR WILL BE A FOCUS FOR WET-WEATHER AS PACIFIC IMPULSES
EJECT E THROUGH RIDGE PATTERN. COMBINATION OF ISENTROPIC ASCENT
BENEATH DIFFLUENCE ALOFT ALLOWING FOR BROADSCALE LIFT...CAN NOT RULE
OUT SHOWERS AROUND MONDAY - TUESDAY. FEEL BETTER CHANCES ARE N/W
AWAY FROM THE ANTICYCLONIC FLOW / DRY AIR AND TOWARDS MORE FAVORABLE
DYNAMICS.
FOR THE REST OF THE WEEK ENSEMBLE AND DETERMINISTIC GUIDANCE SUGGEST
A FLAT-FLOW REGIME ACROSS THE CONUS THROUGH WHICH PACIFIC-ORIGIN
IMPULSES PREVAIL. CONSIDERING THE OFFSHORE BERMUDA HIGH AND A VORTEX
PREVAILING ACROSS CANADA...MAY BE DEALING WITH A MORE ACTIVE PATTERN
AS THE WARM-MOIST FLOW IS STRETCHED ACROSS THE NE CONUS
UNDERGOING LIFT AND ENHANCEMENT AS MID-LEVEL IMPULSES TRANSLATE
THROUGH THE REGION. UNCERTAINTY AS ANY WOBBLE IN THE FLOW PATTERN
BETWEEN THE VORTEX N AND THE BERMUDA HIGH S WOULD MODIFY THE
CONVERGENT FLOW. GFS SUGGESTS A +1 SD OF H925 TEMPERATURES FOR
NEXT WEEK. IF +2 IT WOULD BE MORE LIKELY THAT THE CONVERGENT FLOW
WOULD BE N AND W WITH S NEW ENGLAND WARMER AND DRY BENEATH THE
RIDGE. WITH A CONSENSUS BLEND...WILL KEEP IT SEASONABLE WITH
SLIGHT CHANCE TO CHANCE POPS. ECHOING THE POINT MADE BY THE
PREVIOUS FORECASTER...COULD FIND OURSELVES WITHIN THE STEERING
FLOW OF UPSTREAM MCS/S. CONTINUED SIGNALS OF A CUTOFF LOW WOBBLING
ACROSS THE NW-ATLANTIC. WILL HAVE TO KEEP AN EYE ON THAT.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY/...
TODAY...RAIN SHIELD TRACKS OVER SOUTHEAST CT...SRN HALF OF RI AND
INTO SOUTHEAST MA THRU 12Z...THEN OFFSHORE. MVFR WITHIN THIS AREA
ALONG WITH LOW RISK OF BRIEF IFR. RAIN MAINLY LIGHT. VFR ELSEWHERE.
THEN BECOMING VFR AFT 12Z AS RAIN MOVES OFFSHORE. LOW RISK OF A
SPOT SHOWER LATE THIS AFTERNOON INTO EARLY EVENING.
TONIGHT...WNW WINDS INCREASE UP TO 25 KT IN GUSTS. SPOT SHOWER
POSSIBLE UNTIL 03Z OR SO. OTHERWISE VFR AND DRY WEATHER.
SATURDAY...WEST WINDS UP TO 20 KT IN GUSTS. VFR AND DRY WEATHER
PREVAIL.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
SATURDAY NIGHT INTO SUNDAY NIGHT...HIGH CONFIDENCE.
VFR. BREEZY NW-WINDS THROUGH SATURDAY VEERING SW INTO SUNDAY.
MONDAY INTO MONDAY NIGHT...MODERATE CONFIDENCE.
LOW-END VFR TOWARDS THE LATER-HALF WITH INCREASING -SHRA CHANCES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
RAIN OVERSPREADS THE SOUTHERN WATERS OVERNIGHT AS LOW PRES TRACKS
NEAR OR JUST SOUTH OF 40N/70W BENCHMARK. SOME UNCERTAINTY ON
NORTHERN EXTENT OF RAIN SHIELD. STEADY RAINFALL GIVES WAY TO
SCATTERED SHOWERS FRIDAY AFTERNOON AND EVENING AS A COLD FRONT
APPROACHES FROM THE WEST. GUSTY NORTHWEST WINDS DEVELOP BEHIND
THIS FRONT...WITH THE POTENTIAL FOR GUSTS UP TO 30 KT IN PLACES.
SMALL CRAFT ADVISORIES MAY BE NEEDED SOMETIME FRIDAY NIGHT INTO
SATURDAY...ESPECIALLY ACROSS THE OUTER COASTAL WATERS.
OUTLOOK...SATURDAY THROUGH TUESDAY...
BREEZY NW-WINDS WITH GUSTS OVER 25 KTS THROUGH SATURDAY VEERING SW
INTO SUNDAY AND REMAINING BRISK WITH GUSTS UP TO 20 KTS. LOOKING AT
WAVES BUILDING IN EXCESS OF 5 FEET ON THE OUTER WATERS
MONDAY INTO MONDAY NIGHT...MODERATE CONFIDENCE.
CONTINUED BREEZY SW-WINDS WITH GUSTS UP TO 20 KTS. WAVES IN EXCESS
OF 5-FEET MAY REMAIN ON THE S/SE-WATERS.
&&
.CLIMATE...
RECORD LOWS FOR MAY 23RD...
BOSTON - 40 /1967/
HARTFORD - 37 /1976/
PROVIDENCE - 40 /1950/
WORCESTER - 32 /1929/
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/DOODY
NEAR TERM...NOCERA
SHORT TERM...BELK
LONG TERM...SIPPRELL
AVIATION...NOCERA/SIPPRELL
MARINE...BELK/SIPPRELL
CLIMATE...STAFF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
349 AM EDT FRI MAY 22 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 22 2015
07Z SFC ANALYSIS SHOWS HIGH PRESSURE SETTLING INTO THE MID
MISSISSIPPI AND TENNESSEE VALLEYS WITH LOW PRESSURE TO THE NORTH
AND SOUTHEAST. THIS HAS HELPED TO CLEAR THE SKIES THROUGH EASTERN
KENTUCKY AS A NARROW BAND OF LOWER CLOUDS IS HOLDING ON NEAR THE
VIRGINIA BORDER. PATCHY FOG HAS DEVELOPED IN THE VALLEYS EARLY
THIS MORNING IN THE WAKE OF THE CLEARING AND LEFT OVER GROUND
MOISTURE. IN ADDITION...A FEW PATCHES OF DENSE FOG ARE NOTED IN
THE CUMBERLAND VALLEY AND ALSO ON SOME OF THE RIDGES. WILL MONITOR
THIS VIA THE OBS AND WEB CAMS FOR A POSSIBLE SPS OR NPW THIS
MORNING. AT A MINIMUM...THE PATCHES OF DENSE FOG WILL BE
HIGHLIGHTED IN THE MORNING PORTION OF THE FORTHCOMING HWO.
READINGS ARE RATHER CHILLY THIS MORNING...MAINLY IN THE LOWER AND
MIDDLE 40S WHILE DEWPOINTS ARE GENERALLY A DEGREE OR SO LOWER THAN
DRY BULB TEMPS AMID LIGHT NORTHWEST WINDS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH A DEPARTING TROUGH TO
THE NORTHEAST EARLY TODAY FOLLOWED BY RISING HEIGHTS AS A RIDGE
DEVELOPS OVER THE SOUTHEAST PART OF THE NATION. A BAND OF WEAK
MID LEVEL ENERGY WILL LIFT THROUGH KENTUCKY AND INTO THE OHIO
VALLEY FRIDAY NIGHT DURING THIS TRANSITION...BEFORE THE RIDGE
SHARPENS OVER EAST KENTUCKY ON SATURDAY. GIVEN THE MODEL AGREEMENT
HAVE FAVORED THE NAM12 AND HRRR FOR WX DETAILS DUE TO THEIR
HIGHER RESOLUTION.
SENSIBLE WEATHER WILL FEATURE A PLEASANT 48 HOURS AND BEYOND...
ONCE THIS MORNING/S VALLEY FOG...LOCALLY DENSE...BREAKS UP BY 10
AM. TEMPS WILL BE A BIT WARMER EACH DAY WITH A DECENT RIDGE
VALLEY TEMPERATURE SPLIT EXPECTED TONIGHT...BUT MILDER FOR MOST
PLACES THAN EARLY THIS MORNING. HIGH CLOUDS WILL MOVE IN LATER
TODAY AND CONTINUE TO BUILD ON SATURDAY AS A MOSTLY DRY FRONT
SETTLES INTO THE AREA. A STRAY SHOWER CANNOT BE RULED OUT TONIGHT
TO THE NORTHEAST OF THE AREA AS THAT FRONT INITIALLY APPROACHES
BEFORE THE RIDGE ALOFT BUILDS SIGNIFICANTLY OVER THE CWA BY
SATURDAY MORNING.
USED THE SHORTBLEND AS A STARTING POINT FOR THE T/TD AND WIND
GRIDS THROUGH TODAY BEFORE FOLLOWING TO THE SUPERBLEND. DID MAKE
SOME MODERATE TERRAIN BASED CHANGES TO THE LOW TEMPERATURES
TONIGHT. AS FOR POPS...KEPT THEM MINIMAL THROUGH THE PERIOD...IN
LINE WITH MOS GUIDANCE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 AM EDT FRI MAY 22 2015
THE MODELS ARE IN PRETTY GOOD AGREEMENT TO BEGIN THE EXTENDED
PERIOD...WITH A RIDGE OF HIGH PRESSURE BRINGING WARM AND DRY WEATHER
TO THE AREA SATURDAY NIGHT THROUGH LATE IN THE DAY ON MONDAY. IT
LOOKS AS IF THE OHIO AND TENNESSEE VALLEY REGIONS WILL BE FIRMLY
ENTRENCHED IN THE WARM SECTOR OF AN APPROACHING MID LATITUDE
CYCLONE. THE WARM WEATHER WOULD BE IN RESPONSE TO PERSISTENT
SOUTHERLY WINDS SOUTH OF A STRONG NORTHWARD MOVING WARM FRONT.
SHOULD THE MODELS HOLD TRUE...WE WOULD SEE THE RIDGE BEGIN TO BREAK
DOWN MONDAY AFTERNOON AND EVENING...AS A LARGE STORM SYSTEM
APPROACHES FROM THE WEST. THE FIRST PRECIPITATION IS FORECAST TO
MOVE INTO THE AREA BY EARLY MONDAY MORNING AS WARM MOIST AIR OFF THE
GULF OF MEXICO BEGINS TO INTERACT WITH WHAT LOOKS LIKE A PRE FRONTAL
TROUGH. THE PRECIPITATION WILL GRADUALLY INCREASE IN COVERAGE MONDAY
AND MONDAY NIGHT AS THE FRONT INCHES TOWARD THE AREA. THE MODEL DATA
SUGGESTS THAT THERE WILL BE A GOOD CHANCE OF RAIN FROM MONDAY NIGHT
THROUGH EARLY THURSDAY AFTERNOON...AS THE AFOREMENTIONED COLD FRONT
MOVES SLOWLY ACROSS THE REGION...AND PERHAPS EVEN STALLS OUT FOR A
TIME. THE MEMORIAL DAY HOLIDAY AT THIS TIME LOOKS LIKE IT WILL BE
WARM WITH ONLY A SMALL CHANCE OF RAIN ACROSS THE AREA.
TEMPERATURES DURING THE EXTENDED WILL LIKELY BE WELL ABOVE NORMAL
FOR THE TIME OF YEAR...DUE TO PERSISTENT SOUTHERLY FLOW AND
SUBSIDENCE WARMING ASSOCIATED WITH THE RIDGE OF HIGH PRESSURE
MENTIONED EARLIER IN THIS DISCUSSION. HIGHS ARE FORECAST TO TOP OUT
IN THE LOWER 80S THROUGH MID WEEK...WITH OVERNIGHT LOWS IN THE
60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 210 AM EDT FRI MAY 22 2015
VFR CIGS AND VIS WILL GIVE WAY TO A PERIOD OF BR AT MOST SITES
EARLY FRIDAY MORNING DUE TO DAMP GROUNDS AND CLEARING SKIES.
OCCASIONAL LIFR OR LOWER WILL BE POSSIBLE AT SITE JKL THROUGH THE
EARLY MORNING HOURS. ONCE THE PATCHY FOG BURNS OFF BY 13Z...VFR
CONDITIONS ARE EXPECTED OVERNIGHT THROUGH FRIDAY EVENING. WINDS
WILL BE LIGHT FROM THE NORTHWEST THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1202 AM CDT FRI MAY 22 2015
.AVIATION...
MIX OF FLIGHT CATEGORIES CURRENTLY BEING OBSERVED ACROSS AREA
TERMINALS. FOR THE MOST PART...STRATUS AND DRIZZLE/FOG LOOK TO
CONTINUE OVER E TX/NW LA TERMINALS...WITH THE REMAINDER TO
CONTINUE UNDER MID LEVEL CLOUDS. VFR CONDITIONS SHOULD BE COMMON
AREAWIDE BY MID AFTERNOON LATER TODAY. OTHERWISE...LIGHT ELY TO
NELY WINDS WILL GRADUALLY VEER AROUND TO THE SE AND E AT 5-10 KTS
THROUGHOUT THE PD. /12/
&&
.PREV DISCUSSION... /ISSUED 942 PM CDT THU MAY 21 2015/
DISCUSSION...
PRECIPITATION FOR THE MOST PART HAS ENDED ACROSS THE FOUR STATE
REGION LATE THIS EVENING. SOME REDUCTIONS IN VISIBILITY ACROSS NE
TX FROM THE I-20 CORRIDOR SOUTHWARD SUGGESTS THAT THERE MAY STILL
BE SOME PATCHY DRIZZLE ACROSS THESE LOCATIONS ATTM. FOR THE
EVENING UPDATE...HAVE KEPT SLIGHT CHANCE POPS GOING BASICALLY
ALONG AND SOUTH OF A LINE FROM TYR/GGG TO THE LOWER TOLEDO BEND
RESERVOIR. LATEST 00Z WRF OUTPUT DOES NOT GENERATE ANY PRECIP
ACROSS THIS REGION BUT THIS WILL BE A FAVORABLE REGION FOR WEAK
ISENTROPIC LIFT AS SOUTHERLY WINDS DO RETURN AT THE 8H LEVEL WHICH
WILL OVERRUN A NE WIND IN THE LOWER LEVELS. THE LATEST HRRR OUTPUT
DOES SUGGEST SOME WEAK REDEVELOPMENT ACROSS OUR SOUTHWEST ZONES
AFTER MIDNIGHT.
CONCERNING TEMPERATURES...DID LOWER OVERNIGHT MIN TEMPS A DEGREE
OR TWO...MAINLY ALONG AND SOUTH OF THE I-20 CORRIDOR OF NE TX/N LA
WHERE 02Z TEMPS WERE ONLY A DEGREE OR SO FROM FCST MINS. CLOUD
COVER HAS SCOURED OUT ACROSS OUR EXTREME NW ZONES BUT SHOULD FILL
IN OVERNIGHT WITH 7H MOISTURE.
OTHER CHANGES INCLUDED DEWPOINT/RH AND WIND GRIDS TO MIMIC CURRENT
AND EXPECTED CHANGES OVERNIGHT...OTHERWISE THE FORECAST IS IN
PRETTY GOOD SHAPE.
NO OTHER SIGNIFICANT CHANGES ATTM. PRELIMS ARE AS FOLLOWS...13.
PREV DISCUSSION... /ISSUED 350 PM CDT THU MAY 21 2015/
DISCUSSION...
WATER VAPOR IMAGERY CONTINUES TO SHOW A DISTURBANCE MOVING EAST
THIS AFTERNOON...OUT OF THE ARKLATEX REGION. HOWEVER...SCATTERED
SHOWERS CONTINUE ACROSS THE REGION...WITH THE BRUNT OF THE
SHOWERS EXTENDING FROM LUFKIN EAST TO LOUISIANA. THIS SHOWERS
ACTIVITY WILL GRADUALLY SHIFT SOUTH AND EAST THROUGH THE
EVENING..WITH JUST A FEW ISOLATED SHOWERS CONTINUING INTO THE
OVERNIGHT HOURS.
A TRANSITORY WEAK RIDGE WILL BUILD BACK ACROSS THE ARKLATEX FOR
FRIDAY. AT THIS POINT IN TIME...THINK THAT MOST OF THE REGION WILL
PROBABLY BE DRY...BUT HAVE LEFT IN A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS...MAINLY FOR WESTERN AREAS...AS SOME MOISTURE DOES
TRY TO SPREAD INTO THE AREA FROM TEXAS. THIS RIDGE WILL SHIFT EAST
ON SATURDAY...OPENING THE DOOR FOR A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THE WEEKEND.
THE PERIODS OF MOST CONCERN IN THE FORECAST ARE REALLY SUNDAY AND
MONDAY...AS THE NEXT WEST COAST LOW MOVES INTO THE CENTRAL PART OF
THE US BEFORE PUSHING EAST. SHOWERS AND THUNDERSTORMS WILL LIKELY
DEVELOP ACROSS THE REGION ON SUNDAY...WITH A DISTURBANCE AHEAD OF
THE MAIN TROUGH AIDS IN THE LIFT. THE MAIN TROUGH THEN SHIFTS EAST
ACROSS THE REGION LATE SUNDAY AND INTO MONDAY. PRECIPITABLE WATER
VALUES WILL INCREASE TO BETWEEN 1.6 AND 2.1 INCHES DURING THIS
TIME...MEANING THAT ANY THUNDERSTORMS THAT DEVELOP WILL BE VERY
EFFICIENT RAIN PRODUCERS...WITH PERIODS OF HEAVY RAIN LIKELY.
GIVEN HOW SATURATED THE GROUND IS WITH THE RECENT RAINS...BELIEVE
FLASH FLOODING WILL ALSO BE LIKELY THESE DAYS. HAVE HELD OFF
ISSUING A FLASH FLOOD WATCH FOR SUNDAY AND MONDAY AT THIS
TIME...JUST TO GIVE THE MODELS ANOTHER DAY TO FINE TUNE THE
TIMING...BUT BELIEVE ONE WILL BE NEEDED FOR THESE DAYS.
THE EXTENDED MODELS START TO VARY ON THE TIMING FOR TUESDAY
THROUGH THURSDAY...BUT FOR NOW IT APPEARS THAT THE REGION WILL
EITHER BE UNDER SOUTHWESTERLY FLOW ALOFT OR ANOTHER TROUGH.
THEREFORE...EXPECT THE THREAT OF UNSETTLED WEATHER TO CONTINUE
THROUGH AT LEAST THURSDAY.
HYDROLOGY...
THE POTENTIAL FOR A MAJOR FLOOD TO DEVELOP ALONG THE RED RIVER
CONTINUES TO BE A CONCERN. THE WEATHER PREDICTION CENTER IS
FORECASTING UPWARDS OF 8 INCHES OF PRECIPITATION FALLING OVER THE
RED RIVER BASIN UPSTREAM OF LAKE TEXOMA IN THE NEXT 7 DAYS. THIS
ADDITIONAL RAINFALL ON ALREADY SATURATED GROUND WILL INCREASE
THE LIKELIHOOD OF A MAJOR FLOOD EVENT ALONG THE RED RIVER...THE
FIRST TIME SINCE 1990. OUR MODELS ARE ALSO HINTING THAT A
SIGNIFICANT AMOUNT OF PRECIPITATION MAY FALL ALONG THE RED RIVER
AS THE CREST MOVES SOUTH TOWARDS SHREVEPORT. THIS ADDS AN
ADDITIONAL LEVEL OF CONCERN. NEEDLESS TO SAY...WE WILL CONTINUE
TO MONITOR THIS DEVELOPING SITUATION. FOR MORE INFORMATION ON THE
RED RIVER STAGES AND FORECASTS...PLEASE SEE NEWPNSSHV OR NOUS44
KSHV OR THE CURRENT AND FORECASTED RIVER LEVELS LINK ON OUR
WEBSITE AT WEATHER.GOV/SHV.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 59 77 65 83 / 10 20 20 50
MLU 56 76 63 84 / 10 20 20 50
DEQ 55 72 60 79 / 10 40 20 50
TXK 56 73 61 81 / 10 30 20 50
ELD 54 74 61 82 / 10 20 20 50
TYR 60 76 66 82 / 20 40 20 40
GGG 59 77 66 83 / 20 30 20 40
LFK 64 80 69 84 / 20 40 20 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
123 AM EDT FRI MAY 22 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 329 PM EDT THU MAY 21 2015
SCATTERED RAIN SHOWERS WILL MOVE SOUTH THROUGH THE AREA WITH A COLD
FRONT. BEHIND THIS FRONT...HIGH TEMPERATURES FRIDAY WILL BE AROUND
60...WHICH IS ABOUT 10 DEGREES BELOW NORMAL THIS TIME OF YEAR.
PATCHY FROST IS POSSIBLE OVER PARTS OF CENTRAL LOWER MICHIGAN FRIDAY
MORNING. THERE IS EVEN BETTER POTENTIAL FOR FROST SATURDAY MORNING.
RAIN CHANCES RETURN SUNDAY AFTERNOON WITH A WARMER AND WETTER
PATTERN LASTING WELL INTO NEXT WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 329 PM EDT THU MAY 21 2015
SCATTERED SHOWERS ARE POSSIBLE THIS EVENING. COOLER THAN NORMAL
TEMPERATURES WILL PERSIST THROUGH FRIDAY NIGHT. FROST FORMATION IS
POSSIBLE TONIGHT MAINLY ACROSS CENTRAL LOWER MICHIGAN. WIDESPREAD
AREAS OF FROST ARE MORE LIKELY LATE FRIDAY NIGHT INTO SATURDAY
MORNING.
A WEAK COLD FRONT WILL DROP SOUTH THROUGH LOWER MICHIGAN THIS
EVENING AS AN UPPER LEVEL SHORTWAVE PROPAGATES OVER THE LOWER GREAT
LAKES REGION. MOISTURE IS CONFINED TO THE MID LEVELS WITH CLOUD
BASES AROUND 9K FEET. SFC DEWPOINTS ARE ONLY IN THE 30S TO LOWER
40S. ALL THIS SHOULD RESULT IN ISOLATED TO SCATTERED LIGHT RAIN
SHOWERS...CONFIRMED BY THE LAST SEVERAL RUNS OF THE RAP AND HRRR. A
SIMILAR AIRMASS YESTERDAY EVENING RESULTED IN A RAIN/SLEET MIX
MAINLY IN THE CHICAGO AREA. BUT PRECIP THIS EVENING WILL LIKELY NOT
BE HEAVY ENOUGH TO CAUSE SIGNIFICANT WET-BULBING.
MID-LEVEL CLOUDS WILL START TO CLEAR OUT FROM NORTH TO SOUTH LATE
TONIGHT AND WINDS WILL SUBSIDE AS THEY VEER NORTHERLY BEHIND THE SFC
FRONT. THIS SHOULD ALLOW DECENT RADIATIONAL COOLING CONDITIONS TO
SET UP AFTER MIDNIGHT. FROST WILL BE POSSIBLE ACROSS CENTRAL LOWER
MICHIGAN.
ANOTHER COOL DAY IS EXPECTED ON FRIDAY WITH NORTHWEST FLOW AT THE
SURFACE. BUT PLENTY OF SUNSHINE IS EXPECTED AS A SURFACE HIGH BUILDS
IN. UPPER RIDGING WILL CONTINUE TO BUILD IN THROUGH SATURDAY NIGHT
AS THE SFC HIGH SLIDES OFF TO THE SOUTHEAST. FAIR WEATHER IS
EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT...BUT THIS SHOULD ALLOW
GOOD FROST CONDITIONS TO SET UP FRIDAY NIGHT INTO SATURDAY MORNING.
WITH CLEAR SKIES AND LIGHT WINDS...LOWS WILL LIKELY DROP INTO THE
LOW TO MID 30S ACROSS MUCH OF THE FORECAST AREA. SOUTHWEST RETURN
FLOW FINALLY SETS UP SATURDAY...ALONG WITH PLENTY OF SUNSHINE AND
HIGHS IN THE LOWER 70S.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 329 PM EDT THU MAY 21 2015
THE MAIN STORY IN THE LONG TERM PERIOD IS THAT WE WILL FINALLY SEE
WARMER TEMPERATURES AS THE PERSISTENT HUDSON BAY UPPER LOW RETREATS
AND WE GET INTO DEEP SOUTHWEST FLOW. HIGHS IN THE 70S ARE LIKELY
AWAY FROM LK MI... WITH PERHAPS 80 DEGREES AND NOTICEABLY MORE HUMID
FROM MONDAY ON.
PROLONGED WARM ADVECTION PATTERN WITH A FLOW OFF THE GULF AND A
QUASI STATIONARY FRONTAL BOUNDARY WILL LIKELY LEAD TO ROUNDS OF
SHOWERS AND POSSIBLE TSTMS. HOWEVER THE TIMING/LOCATION/DURATION OF
CONVECTIVE EPISODES AND DAILY POSITION OF THE SFC FRONT IS LOW
CONFIDENCE AT THIS TIME. CURRENTLY WE HAVE THE HIGHEST POPS ON
SUNDAY NIGHT AND MONDAY WHICH IS WHEN THE SFC WARM FRONT IS LIFTING
NORTH THROUGH THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 117 AM EDT FRI MAY 22 2015
A WEAK COLD FRONT IS MOVING THROUGH LOWER MICHIGAN ATTM. WINDS
WILL SHIFT FROM THE SOUTHWEST TO THE NORTH BEHIND THE FRONT...BUT
REMAIN LIGHT OVERNIGHT. LIGHT RAIN SHOWERS ACCOMPANYING THE FRONT
WILL ALSO MOVE SOUTH OF THE TAF SITES BY 09Z. MOSTLY CLEAR SKIES
BEHIND THE FRONT.
&&
.MARINE...
ISSUED AT 913 PM EDT THU MAY 21 2015
WAVES WERE SLIGHTLY HIGHER THAN FORECASTED...MAINLY DUE TO THE
STRONGER FLOW OUT AHEAD OF THE COLD FRONT. THE UPDATED FORECAST
REFLECTS THESE HIGHER VALUES. NO HEADLINE AS THE VALUES WERE BELOW
CRITERIA PLUS WITH THE FRONT TO PUSH SOUTH IN THE NEXT FEW
HOURS...THE WIND VALUES DROP OFF BEHIND IT.
&&
.HYDROLOGY...
ISSUED AT 1240 PM EDT THU MAY 21 2015
NO CONCERNS THROUGH THE WEEKEND. PRECIPITATION THAT COULD AFFECT
MAINSTEM RIVERS IS NOT EXPECTED UNTIL LATE SUNDAY...WHICH MARKS THE
START OF A WETTER PATTERN LASTING WELL INTO THE COMING WORK WEEK.
NATIONAL GUIDANCE ADVERTISES UNIFORM RAINFALL TOTALS OF 1-1.5
INCHES ACROSS THE AREA THROUGH THURSDAY MORNING. GIVEN THAT BASE
FLOWS ARE NEAR OR BELOW NORMAL AND THAT RAIN SHOULD BE SPREAD OUT
OVER TIME...WE EXPECT FAIRLY GENTLE RISES WILL BE UNDERWAY BY THE
MIDDLE OF NEXT WEEK.
THAT SAID...FORECASTING CONVECTIVE RAINFALL THIS FAR OUT IS
HIGHLY UNCERTAIN SO THERE STILL REMAINS A FAIRLY WIDE RANGE OF
POSSIBILITIES FOR RAINFALL AND RIVER RESPONSES AT THIS POINT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MIZ037>040-
043>046.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...EBW
LONG TERM...MEADE
AVIATION...04
HYDROLOGY...TJT
MARINE...MJS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
134 AM EDT FRI MAY 22 2015
.SYNOPSIS...
COOLER HIGH PRESSURE WILL BUILD INTO REGION AND CONTINUE INTO THE
WEEKEND. HIGH PRESSURE WILL SHIFT OFFSHORE EARLY NEXT WEEK WITH
HIGHER HUMIDITY LEVELS RETURNING TO THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM THURSDAY...NEAR-TERM UPDATE TO ADDRESS THE INCREASING
SHOWER ACTIVITY ACROSS THE CWA. WEAK SECONDARY LOW PRESSURE HAS
DEVELOPED ALONG AN OCCLUDING FRONT ACCORDING TO LATEST WPC
ANALYSIS...AND ALONG THIS BOUNDARY SHOWERS HAVE RE-FIRED LOCALLY.
00Z KGSO SOUNDING HAS SOME ELEVATED INSTABILITY FROM ABOUT 950MB UP
THROUGH 750MB...SO SURFACE CONVERGENCE ALONG THE FRONT COMBINED WITH
AT LEAST WEAK MID-LEVEL FORCING ON THE SOUTHERN PERIPHERY OF A
SHORTWAVE MOVING OFF TO THE NORTH WILL DRIVE SHOWERS OVERNIGHT.
SHALLOW INSTABILITY WILL PREVENT LIGHTNING. HIGH RES HRRR AND NSSL
WRF WERE ON THE RIGHT TRACK...AND HAVE LEANED ON THE HRRR HEAVILY
FOR THE OVERNIGHT. HAVE RAMPED POP UP TO CHC ACROSS THE CENTRAL AND
NORTHERN PORTIONS OF THE CWA...BUT BEST CHANCE WILL BE PRETTY MUCH
ALONG THE STATE LINE AS THE BOUNDARY SLOWLY SAGS SOUTHWARD. ANY
SHOWERS WILL ERODE LATE AS THEY HEAD EAST...AND THE DRY/COOL
ADVECTION BEGINS IN EARNEST.
WINDS EARLY WILL BE VARIABLE...BUT ARE EXPECTED TO INCREASE AS THE
FRONT PUSHES SOUTH AND A COOL SURGE DEVELOPS. NORTHERLY WINDS WILL
RISE TO 10 TO 15 MPH LATE...WHICH WILL HELP DRIVE LOWS INTO THE UPR
50S NORTH...LOW 60S IN THE SOUTH.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...AS THE FRONT EXITS THE FORECAST
REGION...COOLER DRY HIGH PRESSURE WILL MOVE IN. GFS AND NAM ARE
SHOWING THE PRECIPITABLE WATER VALUES FALLING TO A RANGE OF 0.5 TO
1 INCHES. THE HIGH PRESSURE CENTER WILL STAY TO THE NORTH DURING
THIS PERIOD. NO PRECIPITATION IS EXPECTED THROUGH THIS PERIOD AND
MAXIMUM TEMPERATURES ARE EXPECTED TO BE IN THE UPPER 70S FRIDAY
AND AROUND 80 ON SATURDAY. LOWS EACH NIGHT SHOULD BOTTOM OUT IN
THE MIDDLE 50S FRIDAY NIGHT AND THE UPPER 50S ON SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...SURFACE HIGH PRESSURE WILL BE CENTERED
JUST TO THE NORTH OF THE AREA AND WILL SHIFT OFF THE COAST BY THE
BEGINNING OF NEXT WEEK. THE AREA WILL SEE A RETURN OF ONSHORE
FLOW...A RETURN TO HIGHER HUMIDITIES...AND A WARM UP IN
TEMPERATURES. ALOFT A RIDGE STUBBORNLY HOLDS ON THROUGH ALMOST
THURSDAY SO THE CHANCES OF PRECIPITATION WILL BE MINIMAL THROUGH
AT LEAST EARLY TUESDAY AND MAYBE AN ISOLATED CHANCE OF A DIURNAL
SHOWERS OR THUNDERSTORMS BY LATE TUESDAY THROUGH THURSDAY. MAXIMUM
TEMPERATURES WILL REBOUND TO AROUND 90 BY TUESDAY AND REMAIN AT
THOSE LEVELS THROUGH THURSDAY. MINIMUM TEMPERATURES WILL BE IN THE
LOWER 60S ON SUNDAY NIGHT AND WILL SLOWLY RISE INTO THE UPPER 60S
BY WEDNESDAY NIGHT.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A COLD FRONT HAD MOVED S AND E OF ALL THE TERMINALS.
A MID CLOUD VFR CEILING WILL GRADUALLY SHRINK THROUGH SUNRISE AS
DRIER AIR CONTINUES TO FILTER INTO THE AREA. DESPITE GOOD
SUBSIDENCE DEVELOPING IN THE PRE-DAWN HOURS AND MOIST SOILS AT
KLBT AND KILM...NO FOG IS EXPECTED AT THESE OR ANY OTHER TERMINAL
AS ELEVATED N WINDS WILL KEEP THE LOW LEVELS MIXED.
AFTER 12Z EXPECT VFR/CLEAR SKIES BELOW 12K AS N-NE WINDS PREVAIL.
IN THE AFTERNOON SCT CUMULUS WILL DEVELOP AS WINDS BECOME LIGHT
NE-E.
EXTENDED OUTLOOK...VFR. MORNING FOG POSSIBLE MONDAY AND TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 AM FRIDAY...A SMALL CRAFT SHOULD EXERCISE CAUTION HEADLINE
HAS BEEN ISSUED FOR ALL THE WATERS...EXCEPT FOR THE SEGMENT FROM
LITTLE RIVER INLET TO MURRELLS INLET.
A NORTHERLY SURGE IS UNDERWAY IN THE WAKE OF A COLD FRONT AND
WINDS WILL INCREASE STEADILY UP TO 20 KT. LATEST MME GUIDANCE
SHOWS 25 KT AT 41013...BUT ONLY 15 KT AT JMPN7. FOR THIS REASON
HAVE PAINTED AN AVERAGE OF 20 KT ACROSS THE WATERS. SEAS WILL BE
IN THE 4 TO 5 FT RANGE...EXCEPT 2 TO 4 FT WHERE A NNE TO NE FETCH
IS GREATLY REDUCED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...A COLD FRONT WILL HAVE PUSHED EAST OF THE
WATERS AND HIGH PRESSURE WILL BUILD OVER THE WATERS. WINDS WILL
BE FROM THE NORTH AT 15 TO 20 KNOTS ON FRIDAY MORNING AND WILL
SLOWLY WEAKEN TO 10 TO 15 KT BY THE OF END FRIDAY AND REMAIN AT
THESE SPEEDS. WINDS WILL BEGIN THE DAY FROM THE NORTH AND WILL
VEER TO THE EAST BY SATURDAY. SEA HEIGHTS WILL START OUT AT 2 TO 4
FEET EARLY FRIDAY AND WILL SETTLE OUT AT 2 TO 3 FEET THROUGH
SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...HIGH PRESSURE WILL RULE THE COASTAL
WATERS WITH SOUTHEAST WINDS OF 10 KNOTS SLOWLY SHIFTING TO THE
SOUTH AT 10 KNOTS BY TUESDAY. SEAS WILL REMAIN AT 2 TO 3 FEET FOR
THE ENTIRE FORECAST PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...DRH
LONG TERM...DRH
AVIATION...MRR/RJD
AREA FORECAST DISCUSSION
NWS NORMAN OK
417 AM CDT FRI MAY 22 2015
.DISCUSSION...
HEAVY RAINFALL AND FLOODING ARE THE MAIN CONCERNS THIS HOLIDAY
WEEKEND. SEVERE THUNDERSTORM POTENTIAL SATURDAY AND SUNDAY ARE
ADDITIONAL CONCERNS.
THE BIGGEST CHANGE TO THE PREVIOUS FORECAST WAS TO EXPAND THE
FLASH FLOOD WATCH TO INCLUDE NORTHERN AND NORTHWESTERN OKLAHOMA.
LATEST MODELS...ESPECIALLY THE ECMWF...DEPICTED HIGHER
QPF/RAINFALL AMOUNTS IN THESE AREAS...GENERALLY 1 TO 4 INCHES...
LATE TONIGHT THROUGH MONDAY...SO BELIEVE THE FLASH FLOODING
POTENTIAL MAY BE INCREASING IN THESE LOCATIONS. THE REST OF THE
WATCH APPEARS TO BE IN GOOD SHAPE.
TODAY...BATCH OF ELEVATED SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE TO MOVE EAST ACROSS THE AREA...MAINLY THIS MORNING...
BRINGING GENERALLY 0.25 TO 0.50 INCHES OF RAINFALL. DUE TO LACK OF
INSTABILITY...NO STRONG OR SEVERE STORMS OR FLASH FLOODING ARE
EXPECTED WITH THIS ACTIVITY. THIS ACTIVITY WILL END WEST TO EAST
LATER THIS MORNING INTO THE AFTERNOON HOURS AND LATEST HRRR RUNS
MAY BE TO SLOW WITH THE PROGRESSION OF THIS RAIN. BELIEVE MOST
LOCATIONS WILL REMAIN MOSTLY CLOUDY AND DRY THIS AFTERNOON. DUE
TO CLOUD COVER...WENT TOWARDS THE COOLER SIDE OF MODEL GUIDANCE
FOR HIGHS. SOME PATCHY FOG MAY FORM IN WESTERN NORTH TEXAS AND
WESTERN OKLAHOMA TODAY AS LOW LEVELS MOISTEN. THE TRUE SURFACE
WARM FRONT IS EXPECTED TO STAY SOUTH OF THE AREA.
TONIGHT...MAINLY DRY CONDITIONS SHOULD OCCUR THROUGH MIDNIGHT
BEFORE RAIN CHANCES SLOWLY INCREASE. KEPT THE HIGHEST RAIN
CHANCES AFTER MIDNIGHT IN NORTHWESTERN OKLAHOMA. SEVERE POTENTIAL
AND HEAVY RAINFALL SEEM TO BE RATHER LOW TONIGHT IN THESE
LOCATIONS. WOULD NOT BE SURPRISED IF THERE WAS SOME FOG ACROSS THE
AREA...BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE.
SATURDAY AND SATURDAY NIGHT...FLOODING CONCERNS WILL INCREASE AS
SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL INCREASE IN
COVERAGE AND SPREAD EAST DURING THE DAY. THERE SEEMS TO BE A
SIGNAL FROM THE MODELS THAT NORTHWESTERN OKLAHOMA MAY HAVE THE
HIGHEST RAINFALL TOTALS DURING THE MORNING...SPREADING TO THE I-44
CORRIDOR AND POINTS SOUTHEAST BY SATURDAY NIGHT. KEPT HIGH RAIN
CHANCES IN THE FORECAST. PRECIPITABLE WATER VALUES ARE FORECAST TO
APPROACH NEARLY 2 INCHES WHICH WOULD BE NEAR RECORD LEVELS. VERY
HEAVY RAIN RATES OVER 2 INCHES PER HOUR ARE POSSIBLE AND WOULD
ONLY INCREASE FLASH FLOODING POTENTIAL.
IN REGARDS TO SEVERE POTENTIAL SATURDAY AND SATURDAY NIGHT...
BELIEVE THERE IS SOME POTENTIAL...BUT CONFIDENCE IN TIMING...
LOCATIONS...AND STORM MODE REMAIN LOW. MESOSCALE DETAILS WILL
DICTATE WHAT OCCURS. CLOUD COVER MAY LIMIT INSTABILITY.
HOWEVER...STRONG SHEAR INCLUDING THE LOW LEVELS AND ABUNDANT
MOISTURE MAY SUPPORT AT LEAST A LOW TORNADO THREAT. SOME DAMAGING
WINDS AND HAIL MAY OCCUR. STILL BELIEVE FLOODING AND POSSIBLE
TRAINING OF HEAVY RAINFALL WILL BE THE MAIN CONCERNS.
SUNDAY AND SUNDAY NIGHT...THE FLOODING AND HEAVY RAINFALL THREAT
WILL CONTINUE ACROSS THE AREA. WHAT HAPPENS ON SATURDAY WILL HAVE
A BIG INFLUENCE ON WHAT OCCURS SUNDAY AND SUNDAY NIGHT. GENERALLY
THINK THE HEAVIEST RAINFALL AXIS WILL SHIFT SOUTHEAST OF I-44.
SEVERE POTENTIAL REMAINS VERY UNCERTAIN AS CLOUD COVER AND RAIN
MAY STABILIZE THE AIR. HOWEVER...IF SOME CLEARING AND
DESTABILIZATION OCCURS...THE SEVERE WEATHER POTENTIAL WOULD
INCREASE CONSIDERABLY...ESPECIALLY AS SHEAR IS FORECAST TO BE
HIGHER ON SUNDAY COMPARED TO SATURDAY.
MONDAY AND MONDAY NIGHT...RAIN CHANCES WILL DECREASE SLIGHTLY
ACROSS THE AREA...THOUGH A FEW STORMS WITH HEAVY RAINFALL MAY
CONTINUE TO AGGRAVATE ONGOING FLOODING. CAPPING WILL REMAIN RATHER
WEAK. SHEAR WILL WEAKEN. HOWEVER...THE AIR WILL REMAIN MOIST AND
PERHAPS MORE UNSTABLE COMPARED TO SUNDAY. THINK THERE WILL BE MANY
MORE DRY HOURS ON MONDAY COMPARED TO WET ONES.
TUESDAY THROUGH THURSDAY...A WARM MOIST AIRMASS WILL REMAIN NEARBY
WITH AT LEAST SOME LOW CHANCES FOR STORMS MOST DAYS. INCREASING
MID LEVEL HEIGHTS AND WEAK RIDGING SHOULD DECREASE STORM COVERAGE. ANY
STORM WOULD BE SLOW MOVING AND COULD PRODUCE ADDITIONAL LOCALLY
HEAVY RAINFALL. TEMPERATURES ARE FORECAST TO BE NEAR AVERAGE.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 63 60 76 63 / 90 40 90 90
HOBART OK 65 60 73 61 / 70 50 90 60
WICHITA FALLS TX 69 63 79 64 / 90 30 90 90
GAGE OK 63 57 68 58 / 50 60 90 30
PONCA CITY OK 61 58 70 63 / 90 60 90 80
DURANT OK 69 61 78 65 / 70 20 60 90
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR OKZ004>048-050>052.
TX...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR TXZ083>090.
&&
$$
23/17
AREA FORECAST DISCUSSION
NWS TULSA OK
1143 PM CDT THU MAY 21 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS EXPECTED THROUGH THE NIGHT FOR ALL SITES.
AREAS OF SHOWERS AND A FEW THUNDERSTORMS WILL BEGIN TO MOVE
INTO EASTERN OK AFTER 15-16Z...ALONG WITH AREAS OF MVFR CIGS.
PRECIPITATION SHOULD MOVE INTO WESTERN AR AFTER 18-20Z.
&&
.PREV DISCUSSION... /ISSUED 830 PM CDT THU MAY 21 2015/
DISCUSSION...
NEXT ROUND OF SHOWERS AND THUNDERSTORMS TO AFFECT EASTERN OKLAHOMA
AND WESTERN ARKANSAS WILL ENCROACH ON THE AREA FROM THE WEST TONIGHT
AND MAY ENTER THE WESTERN FRINGES OF THE COUNTY WARNING AREA BY 12Z.
ANOTHER MID-LEVEL SHORTWAVE WILL MOVE OUT OF SOUTHWEST UNITED STATES
TONIGHT AND ACROSS THE PLAINS ON FRIDAY BRINGING THE SHOWERS AND
THUNDERSTORMS TO THE AREA. HAVE LOWERED POPS EAST OF HIGHWAY 75 FOR TONIGHT
AS THE HRRR HAS TRENDED A BIT SLOWER ON BRINGING THE PRECIPITATION INTO
THE AREA. HAVE ALSO MADE SOME ADJUSTMENTS TO THE SKY GRIDS FOR TONIGHT.
OTHERWISE...CURRENT FORECAST IS ON TRACK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 51 60 55 73 / 10 80 50 70
FSM 53 62 56 76 / 10 70 40 50
MLC 54 63 58 76 / 20 80 40 50
BVO 48 60 53 72 / 10 80 50 70
FYV 46 61 54 72 / 10 70 50 50
BYV 46 63 52 71 / 10 50 40 50
MKO 52 60 56 75 / 10 80 50 60
MIO 47 63 53 73 / 10 70 40 60
F10 53 61 57 75 / 20 80 50 60
HHW 57 67 59 78 / 10 60 30 50
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 7 AM MONDAY FOR OKZ049-
OKZ053-OKZ054-OKZ055-OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-
OKZ061-OKZ062-OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-
OKZ069-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076.
AR...FLASH FLOOD WATCH FROM 1 PM SUNDAY TO 7 AM MONDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011-ARZ019-ARZ020-ARZ029.
&&
$$
AVIATION...18
AREA FORECAST DISCUSSION
NWS PORTLAND
227 AM PDT FRI MAY 22 2015
.SYNOPSIS...THE MARINE LAYER WILL DEEPEN FRIDAY AND MOVE
THE THREAT FOR THUNDERSTORMS OVER AND EAST OF THE CASCADES BY FRIDAY
EVENING. STRONG ONSHORE FLOW WILL CONTINUE THROUGH SATURDAY...THEN
WEAKEN A LITTLE SUNDAY. ANOTHER UPPER LOW LOOKS LIKE IT WILL APPROACH
THE AREA EARLY NEXT WEEK...GENERALLY BRINGING CONTINUED SHOWER
CHANCES.
&&
.SHORT TERM...SHOWERS AND THUNDERSTORMS CONTINUE TONIGHT GENERALLY
FROM THE EASTERN COAST RANGE EAST THROUGH THE CASCADES. WITH THE FLOW
PATTERN HAVING SHIFTED FROM THE NORTH AS LOW PRESSURE APPROACHES FROM
THE NORTHWEST...HAVE MADE THE FORECAST PERSISTENT WITH
SHOWER CHANCES AND A SLIGHT CHANCE OF THUNDER THROUGH MUCH OF THE
AFTERNOON. SOME SHOWERS LOOK LIKE THEY MAY EVEN MAKE IT TOWARD THE
COAST...SO HAVE TAKEN OUT THE MENTION OF DRIZZLE FOR NOW BUT WILL BE
KEEPING A CLOSE EYE ON HOW THINGS PROGRESS OVER THE NEXT FEW HOURS
AND MAY MAKE ANOTHER UPDATE BASED ON RADAR TRENDS. AS IT STANDS...THE
SHORT-TERM HIGH RESOLUTION MODELS AGREE WITH THE CONTINUATION OF
SHOWERS THROUGH THE FRIDAY MORNING HOURS.
THERE WILL BE LITTLE CHANGE IN THE WEATHER PATTERN FRIDAY NIGHT AND
SATURDAY AS THE UPPER LOW REMAINS OVER THE REGION. A DEEP MARINE
LAYER WILL MAINTAIN CLOUDY SKIES AND POSSIBLY PRODUCE DRIZZLE
SATURDAY MORNING. THE LOW WILL MOVE FURTHER INLAND SATURDAY
AFTERNOON...BUT STILL MAY PRODUCE SOME MOUNTAIN SHOWERS.
MODELS STILL SHOWING LARGE DIFFERENCES SUNDAY AND BEYOND.
IF THE ECMWF IS CORRECT...THERE WOULD BE STRONGER ONSHORE FLOW SUN
WITH LESS AFTERNOON SUN. THE GFS AND NAM HAVE LESS ONSHORE FLOW. IN
ANY EVENT...GENERAL CONDITIONS LOOK STABLE...WITH ANY SHOWER THREAT
CONFINED TO NRN CASCADES. BOWEN/TJ
.LONG TERM...NO SIGNIFICANT CHANGES. PREVIOUS DISCUSSION
FOLLOWS...SUNDAY NIGHT THROUGH THURSDAY...GFS AND ECMWF BOTH SHOW AN
UPPER LEVEL LOW OR TROUGH SITTING OVER OREGON AND WASHINGTON THROUGH
TUE. MAIN MODEL DIFFERENCE IS THAT THE GFS MAINTAINS A CLOSED
FEATURE...KEEPING IT OVER SW WA...WHILE THE ECMWF HAS MORE OF AN OPEN
TROUGH A LITTLE MORE EAST THAN THE GFS. REGARDLESS OF WHICH MODEL
VERIFIES BEST...THE MAIN SENSIBLE WEATHER FOR THE CWA WOULD BE
CONTINUED ONSHORE LOW-LEVEL FLOW WITH THE BEST THREAT OF
SHOWERS...ALBEIT SMALL...OVER THE CASCADES. THE GFS HOLDS THE UPPER
LOW SOMEWHERE OVER SE WA WED...WHILE THE ECMWF HAS A MORE PROGRESSIVE
NWLY FLOW ALOFT. HAVE GONE WITH SLIGHT CHANCE POPS FOR THE CASCADES
WED...BUT IF THE GFS IS MORE RIGHT...THEN IT WOULD BE DRY. TOO MUCH
UNCERTAINTY TO TOTALLY DISREGARD ANY PRECIP THREAT. WEISHAAR
&&
.AVIATION...AS ONSHORE FLOW CONTINUES...THE LOW END MVFR TO IFR CIGS
ALONG THE COAST ARE EXPECTED TO SLOWLY LIFT UP INTO AN MVFR CIG
TODAY. EXPECT THE MVFR CIGS TO SPREAD INTO INLAND VALLEYS THIS
MORNING...AFFECTING VALLEY TAF SITES BY 12Z. THE INLAND CLOUDS ARE
LIKELY TO BREAK UP INTO A SCATTERED CLOUD LAYER BETWEEN 20Z AND 22Z
LEAVING INLAND AREAS VFR. MVFR CIGS ARE LIKELY TO REMAIN ALONG THE
COAST THROUGH 10Z TONIGHT...AND SPREAD BACK INTO INLAND VALLEYS
AGAIN AFTER 09Z.
KPDX AND APPROACHES...MVFR CIGS EXPECTED TO SPREAD IN BETWEEN 09Z
AND 11Z THIS MORNING...THEN BREAK UP AGAIN TO VFR CONDITIONS BETWEEN
20Z AND 22Z THIS AFTERNOON. ONSHORE FLOW WILL AGAIN SPREAD MARINE
CLOUDS WITH MVFR CIGS BACK INLAND AFTER 09Z TONIGHT.
&&
.MARINE...PERSISTENT HIGH PRES WELL OFFSHORE WILL KEEP BELOW SMALL
CRAFT WINDS OUT OF THE NW THROUGH EARLY NEXT WEEK. A FRESH SWELL OF
5 TO 6 FT WILL ALSO CONTINUE OUT OF THE WNW.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
[top]
Area Forecast Discussion
National Weather Service Spokane WA
1000 PM PDT THU MAY 21 2015
.SYNOPSIS...
The chances of showers and thunderstorms will increase by Friday
into Monday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain, especially near the Cascades. The weather remains
showery, with some threat of thunderstorms, each day through next
week.
&&
.DISCUSSION...
Update: Satellite composites shows a closed low off the southern
California coast, with another closed low near the Central British
Columbia coast. This pattern is drawing up quite a bit of mid
level moisture across much of the western US...including southeast
Washington extending northwest through the Columbia basin and the
Washington Cascades. For the remainder of tonight models show
some isolated/scattered shower activity to persist in the same
aformentioned areas as moisture continues to get drawn up into the
area. Mid level instability with MUCAPE values around 200-400 J/KG
could also result in a few stray thunderstorms mainly in the
evening as the instability begins to decrease during the overnight
hours. Conditions will remain dry across Northeast Washington into
the North Idaho Panhandle. The forecast overall looks good and do
not plan any major updates for the rest of tonight.
For tomorrow the concern for flash flooding in the Cascades
remains valid with slow moving wet thunderstorms expected.
A flash flood watch remains in effect for Friday afternoon and
evening. JW
&&
.AVIATION...
06Z TAFS: Scattered showers is expected for the remainder of
tonight mainly in the Cascades and across Central and southern
section of Eastern Washington and the Lewiston area as moisture
continues to be pulled into the area. A couple stray lightning
strikes will also be possible but should not impact any of the TAF
sites. Afternoon convection will again develop on Friday over
similar areas as today. The HRRR shows convection will begin to
fire over the high terrain of the Cascades and Blue Mountains
around 18z Fri. Gusty outflow winds and brief heavy rain will be
the main threats from Thunderstorms on Friday. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 53 80 52 72 47 76 / 10 10 30 30 30 30
Coeur d`Alene 51 80 51 72 48 76 / 10 10 20 30 30 30
Pullman 50 75 47 67 43 70 / 20 30 50 40 40 40
Lewiston 58 79 54 73 52 77 / 20 40 60 50 40 30
Colville 52 84 53 80 50 79 / 10 10 10 20 20 30
Sandpoint 47 80 48 75 47 76 / 0 10 20 30 20 20
Kellogg 49 79 49 72 45 76 / 10 20 30 40 40 30
Moses Lake 55 85 52 76 50 76 / 20 30 30 30 40 30
Wenatchee 60 82 56 76 55 76 / 20 50 40 50 30 30
Omak 52 86 54 79 52 77 / 20 30 30 50 40 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch from Friday afternoon through Friday evening
for East Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
627 AM EDT FRI MAY 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION LATER THIS AFTERNOON, THEN HIGH
PRESSURE BUILDS IN SATURDAY BEFORE SHIFTING OFFSHORE SATURDAY NIGHT
AND SUNDAY. A WARM FRONT IS FORECAST TO LIFT NORTH ACROSS OUR AREA
DURING MONDAY. A COLD FRONT IS THEN ANTICIPATED TO REMAIN WELL TO
OUR NORTH AND WEST WEDNESDAY AND THURSDAY AS HIGH PRESSURE REMAINS
ANCHORED IN THE WESTERN ATLANTIC.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY...SUNNY THIS MORNING THEN PARTLY SUNNY THIS AFTN AS A BAND
OF MODEST INSTABILITY CLOUDINESS AHEAD OF A CFP PASSES SEWD
THROUGH THE AREA WITH DECENT TOTAL TOTALS BUT ALMOST ZERO MLCAPE
(PROBABLY NOT ENOUGH MOISTURE FOR ANYTHING OTHER THAN A POSSIBLE
HIGH BASED SPRINKLE OR .01 SHOWER WITH GUSTY NORTHWEST WINDS TO
35KT). WE NOTED SUPPORT FOR THIS IN THE 00Z/22 NSSL WRF AND SPC
WRF. THE HRRR NOW HAS A GROUP OF SHOWERS RUNNING ESEWD THROUGH E
CENTRAL PA AND CENTRAL NJ IN THE 20-23Z TIME FRAME.
INCREASINGLY GUSTY WEST WINDS AHEAD OF THE COLD FRONT WITH 20 MPH
THIS MORNING AND 28-38 MPH BY MID AFTN. THE WSHIFT TO NNW ARRIVES
VCNTY I-80 IN THE 6P TIME FRAME (WHICH IS REALLY THIS EVENING-
EARLY TONIGHT).
TEMPS REBOUND AFTER YDYS 12 TO 18 BELOW NORMAL MAX TEMPS WITH THIS
AFTNS TEMPS ABOUT 15-20 DEGREES WARMER COMPARED TO THURSDAY AFTN
(NEAR NORMAL MAX`S).
FORECAST GENERATED GENERALLY FROM A 5050 BLEND OF 00Z/22 NCEP MOS
GUIDANCE (GFS/NAM).
CONFIDENCE: ABOVE AVERAGE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
CLEAR AND TURNING CHILLY AS THE CFP NEAR I-80 (NE PA/NNJ) IN THE
6P TIME FRAME SLIPS DOWN TO VCNTY KACY-KPHL AROUND 11P WITH A
PERIOD OF GUSTY NORTH-NORTHWEST WINDS OF 20-25 MPH EXPECTED EARLY
AT NIGHT THEN DECOUPLING-RAPIDLY DIMINISHING WIND LATE AS TEMPS
FALL RAPIDLY.
WILL CONTINUE A TOUCH OF SCT FROST FROM WARREN-SUSSEX COUNTIES IN
NW NJ INTO MONROE AND CARBON COUNTIES OF NE PA. JUST NOT ENOUGH
COVERAGE EXPECTED FOR A FROST ADVY. ALSO WITH FULL GREENUP, PROBABLY
ENOUGH LEAF COVER TO PREVENT MUCH DAMAGE. STILL, CANT BE ABSOLUTELY
SURE AND SO PATCHY FROST IS IN THE FCST AND POSSIBLE SPS MATERIAL
LATER TODAY FOR THOSE LOCATED IN SUCH PLACES AS WALPACK, PEQUEST,
THE TYPICALLY COLDEST LOW LYING AREAS IN THE NW FRINGE OF OUR
FORECAST AREA.
A BIT OF HIGH THIN CIRRUS POSSIBLE TOWARD SUNRISE SATURDAY?
FCST GENERALLY FROM A 5050 BLEND OF 00Z/22 NCEP MOS GUIDANCE
(GFS/NAM).
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF A CLOSED LOW MOVING FROM NORTHERN
NEW ENGLAND TO THE CANADIAN MARITIMES SATURDAY. THIS IS DUE TO
ENERGY STARTING TO EJECT INTO THE CENTRAL AND SOUTHERN PLAINS, WHICH
WILL ALSO BUILD A RIDGE FROM FLORIDA NORTHWESTWARD INTO THE MIDWEST
SATURDAY INTO MONDAY. THE RIDGE STRENGTHENS SOME AS IT SHIFTS
EASTWARD MONDAY AND TUESDAY, HOWEVER IT SHOULD THEN START TO FLATTEN
SOME ON ITS NORTHERN SIDE FROM ABOUT TUESDAY ONWARD. THE MAIN
FEATURE IS A FRONTAL BOUNDARY THAT SLIDES ACROSS THE NORTHEAST BUT
THIS THEN LIFTS BACK NORTHWARD AS A WARM FRONT MONDAY. IT LOOKS TO
TURN RATHER WARM TO EVEN HOT NEXT WEEK AS THE UPPER-LEVEL RIDGE IS
IN PLACE DESPITE IT GRADUALLY SHIFTING MORE OFFSHORE WITH TIME. WE
USED A MODEL BLEND FOR SATURDAY THROUGH MONDAY, THEN THE 00Z WPC
GUIDANCE WITH CONTINUITY THEREAFTER. SOME TWEAKS WERE THEN MADE
FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES.
FOR SATURDAY...A CHILLY START /PATCHY FROST UP NORTH/, OTHERWISE
HIGH PRESSURE STARTS TO SHIFT OFFSHORE AT NIGHT AS RIDGING BUILDS TO
OUR WEST. THE AIRMASS WILL BE COOL, THEREFORE HIGHS SHOULD BE IN THE
60S TO ABOUT 70 DEGREES ACROSS THE REGION. DUE TO HIGH PRESSURE IN
PLACE, LESS WIND IS EXPECTED COMPARED TO FRIDAY.
FOR SUNDAY AND MONDAY...A RIDGE TO OUR WEST WILL GRADUALLY BUILD
EASTWARD. SOME ENERGY SLIDING SOUTHEASTWARD ACROSS NORTHERN NEW
ENGLAND WILL DROP A FRONTAL BOUNDARY INTO OUR AREA SUNDAY NIGHT.
THIS BOUNDARY GENERALLY LOOKS TO BE ON THE WEAK SIDE, HOWEVER IT
COULD BE ACTIVATED MONDAY AS IT LIFTS NORTHWARD AS A WARM FRONT. AS
THE RIDGE BUILDS, OUR AREA IS STILL WITHIN THE NORTHWESTERLY FLOW
ALOFT. THE LOW-LEVEL FLOW IS FORECAST TO BE SOUTHWESTERLY, AND THE
COMBINATION OF WAA AND SOME FRONTAL LIFT AIDED BY SOME SHORT WAVE
ENERGY ALONG THE FRONT SHOULD PRODUCE SOME CONVECTION ON MONDAY. IT
APPEARS THAT THE BULK OF THE WAA/LIFT IS AIMED UP THE OHIO VALLEY
AND ACROSS THE GREAT LAKES. WE WILL NEED TO WATCH THIS THOUGH AS
SOME CONVECTION COULD SLIP INTO OUR AREA FROM THE WEST/NORTHWEST,
ESPECIALLY THE NORTHERN HALF, DURING MONDAY BEFORE THE RIDGE AXIS
REACHES OUR CWA. THE AMOUNT OF INSTABILITY WILL BE KEY AS WE
CONTINUE TO RECOVER FROM A RATHER DRY AIRMASS THAT IS IN PLACE PRIOR
TO MONDAY. OVERALL, CONVECTION MAY PRODUCE AT LEAST LOCALLY HEAVY
DOWNPOURS MONDAY. A MUCH WARMER AIRMASS IS EXPECTED TO OVERSPREAD
THE AREA ESPECIALLY MONDAY AS AN EXPANDING WARM SECTOR MOVES NORTH,
AND SOME INCREASE IN THE DEW POINTS WILL ALSO OCCUR.
FOR TUESDAY AND WEDNESDAY...WE ARE EXPECTED TO BE IN THE WARM SECTOR
DURING THIS TIME FRAME AS A SHORT WAVE ALOFT AND SURFACE LOW TRACKS
TO OUR NORTH, WHICH WILL FLATTEN THE RIDGE SOME. WHILE THE SURFACE
COLD FRONT IS CURRENTLY FORECAST TO STAY WELL TO OUR NORTH AND WEST,
SOME CONVECTION CANNOT BE RULED OUT. THIS APPEARS TO BE MAINLY
FOCUSED NEAR A LEE SIDE TROUGH IN THE PRESENCE OF A WARM/HOT AND
INCREASINGLY HUMID AIRMASS. GIVEN THE PRESENCE OF THE RIDGE AND THE
NORTHWESTERLY FLOW ALOFT BREAKING DOWN ACROSS OUR AREA, ANY
CONVECTION COULD BE SLOW MOVING WHICH WOULD RESULT IN LOCALLY HEAVY
RAIN. AS OF NOW, THE WESTERN ZONES HAVE A HIGHER CHC OF CONVECTION
GIVEN THE FORECAST PLACEMENT OF THE RIDGE AND ALSO A LEE SIDE
TROUGH. SOME PLACES ARE FORECAST TO REACH 90 DEGREES EACH AFTERNOON.
THE AFTERNOON HEAT INDICES ARE FORECAST TO BE CLOSE TO 95 DEGREES
ESPECIALLY WEDNESDAY AFTERNOON FOR THE URBANIZED AREAS OF THE
PHILADELPHIA METRO. IT SHOULD BE COOLER ALONG THE COAST DUE TO A
SOUTHERLY FLOW.
FOR THURSDAY...IT LOOKS TO BE A REPEAT OF THE PREVIOUS TWO DAYS AS
WE REMAIN IN THE WARM SECTOR, MEANWHILE A COLD FRONT SLOWLY SAGS
SOUTHEASTWARD ACROSS THE GREAT LAKES. SOME OF THE GUIDANCE IS FASTER
WITH THIS FRONT, HOWEVER WE WENT WITH THE WPC TIMING. ONCE AGAIN A
WARM TO EVEN HOT DAY IS ANTICIPATED, ALTHOUGH IT MAY BE A LITTLE
COOLER AS THE RIDGE WEAKENS SOME. SINCE A SOUTHERLY FLOW IS
FORECAST, IT SHOULD BE COOLER ALONG THE COAST. SOME MAINLY AFTERNOON
AND EVENING CONVECTION IS POSSIBLE ESPECIALLY INLAND, PROBABLY
FOCUSED ALONG A LEE SIDE TROUGH.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...MOSTLY VFR PRIOR TO 12Z WITH A LIGHT W-NW WIND. ANY REMAINING
MVFR FOG SE NJ SOON DISSIPATES. THEN AFTER 12Z...VFR CLEAR BECOMING
SCT-BKN AOA 6000 FT THIS AFTN WITH THE SLIGHT CHC OF A WLY 38KT
GUSTY SPRINKLE OR LIGHT SHOWER AHEAD OF A COLD FRONT. GENERALLY
GRADIENT WLY GUSTS 20 KT THIS MORNING INCREASE TO 25-33 KT THIS
AFTN.
TONIGHT...VFR CLEAR. THIN CIRRUS POSSIBLE TOWARD SUNRISE SATURDAY.
WSHIFT TO 20-25KT GUSTY NNW THIS EVENING FROM NORTH TO SOUTH, FIRST
NEAR I-80 AROUND 00Z REACHING KPHL/KACY AROUND 03-05Z.
CONFIDENCE: ABOVE AVERAGE.
OUTLOOK...
SATURDAY...VFR. NORTHWEST WINDS AROUND 10 KNOTS, BECOMING WEST-
SOUTHWEST DURING THE AFTERNOON.
SUNDAY...VFR. SOUTHWEST WINDS 10 TO 15 KNOTS, THEN DIMINISHING SOME
AT NIGHT.
MONDAY AND TUESDAY...MAINLY VFR. SOME SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ESPECIALLY DURING MONDAY. SOUTHWEST WINDS MAINLY AROUND
10 KNOTS.
&&
.MARINE...
SAFE BOATING WEEK CONCLUDES TODAY. OUR FINAL PUBLIC INFORMATION
STATEMENT FOR THIS SEASON POSTED AT 408 AM WITH THE SOCIAL MEDIA
POST AROUND 8AM. I DID GO AHEAD AND ADD THE NEW USCG SAFETY APP TO
MY SMART PHONE, JUST IN CASE IT COMES IN HANDY VIA MARINE RELATED
TALKS/INTERVIEWS.
THE FORECAST...
STARTED SCA IMMEDIATELY ON DE BAY. 26 KT SHIP JOHN AND 30 KT CAPE
MAY MESONET AS OF ABOUT 620 AM.
SCA VCNTY 44009 EARLY TODAY WITH SEAS NOW RESPONDING.
OTRW...SCA ALL OTHER WATERS WITH THE PRIMARY THREAT PERIOD OF 2P-
MIDNIGHT. WLY WIND GST 25-30 KT THIS AFTN AHEAD OF A COLD FRONT
THEN JUST AFT OF THE COLD FRONTAL PASSAGE WIND SHIFT TO NNW THIS
EVENING. STRONGEST WIND NEAR THE SHORE WHERE ITS WARMER AND BETTER
MIXING-MOMENTUM TRANSFER.
WINDS DIMINISH TOWARD SUNRISE SATURDAY.
OUTLOOK...
SATURDAY AND SUNDAY...NORTHWEST WINDS DIMINISHING SATURDAY AND THEN
BECOMING SOUTHWEST TOWARD EVENING. THE SOUTHWESTERLY FLOW CONTINUES
SUNDAY AND SHOULD INCREASE SOME, HOWEVER OVERALL THE CONDITIONS
SHOULD BE BELOW ADVISORY CRITERIA.
MONDAY AND TUESDAY...A SOUTHWESTERLY FLOW OF 10-20 KNOTS IS
ANTICIPATED WITHIN A WARM/HOT AIRMASS. THIS MAY RESULT IN THE HIGHER
WINDS CLOSER TO THE COAST. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ESPECIALLY MONDAY. SEAS AT OR BELOW 4 FEET, ALTHOUGH THESE
MAY NEAR 5 FEET TUESDAY ACROSS THE NORTHERN COASTAL WATERS.
&&
.FIRE WEATHER...
WIND GUSTS OF 25 TO 35 MPH ARE EXPECTED THIS AFTERNOON AND RELATIVE
HUMIDITY VALUES SHOULD FALL INTO THE 20 TO 30 PERCENT RANGE IN
MUCH OF OUR REGION AT THAT TIME. HOWEVER, YESTERDAYS RAINFALL IS
FORECAST TO KEEP FINE FUEL MOISTURE FROM FALLING BELOW CRITICAL
LEVELS AT THOSE LOCATIONS WHERE THE GREEN-UP IS NOT COMPLETE, MOST
NOTABLY THE PINE BARRENS. AS A RESULT, WE ARE NOT ANTICIPATING ANY
FIRE WEATHER ISSUES FOR FRIDAY.
&&
.RIP CURRENTS...
POTENTIAL HEAT WAVE NEXT WEEK. THIS PLUS WATER TEMPS CONTINUING ABOVE
NORMAL IS NOT GOOD FOR SAFETY. ONCE IT TURNS HOT AND BEACHES ARE
UNGUARDED, SWIMMERS MAY TAKE CHANCES AT UNGUARDED LOCATIONS. BE SMART
ABOUT ANY SWIMMING EARLY THIS SEASON.
RIP CURRENT AWARENESS WEEK FOR MT HOLLY IS JUNE 7-13 WITH PSAS
VIA PUBLIC INFORMATION STATEMENTS, SOCIAL MEDIA, NOAA WEATHER
RADIO AND ANY MEDIA INTERVIEWS DESIRED (CONTACT OFFICE).
FOR RIP CURRENTS: DESPITE ANTICIPATED PROJECTIONS OF LOW OR
MODERATE RISK THROUGH THE MEMORIAL DAY WEEKEND, EARLY SEASON
FATALITIES OCCUR WHEN SWIMMING AT UNGUARDED TIMES/LOCATIONS.
WEAKER SWIMMERS OR SWIMMING IN AREAS WHERE RIP CURRENTS ARE
STRONGER (JETTIES) CAN QUICKLY BECOME LIFE THREATENING. WHEN
TRAINED LIFEGUARDS ARE NOT NEARBY, TIMELY RESCUE IS MUCH LESS
LIKELY. LETS GET THROUGH THE MONTH OF MAY WITH ALL SWIMMERS SAFE!
PLEASE BROADCAST THIS MESSAGE: FOR ULTIMATE SAFETY, ALWAYS SWIM
IN THE PRESENCE OF LIFE GUARDS! THANK YOU!
&&
.CLIMATE...
**LITTLE DOUBT THAT A TOP 10 WARMEST MAY WILL OCCUR IN LARGE
PORTIONS OF OUR FORECAST AREA**
THE FIRST 21 DAYS OF MAY IN OUR FORECAST AREA WERE AVERAGING
ABOUT 6 DEGREES ABOVE NORMAL.
RUNNING THE NUMBERS FROM THIS MORNINGS 330AM FCST THROUGH THE
28TH AND THE 00Z/22 FTPRHA (GFS MOS) FOR THE LAST 3 DAYS BEYOND
OUR WFO RESPONSIBILITY (29-31) WE FIND THE FOLLOWING.
FOR PHILADELPHIA...PERIOD OF RECORD (POR) BACK TO 1874.
PROJECTING A MONTHLY AVERAGE TEMPERATURE OF 69 TO 70, AT LEAST 5
TO 6 DEGREES ABOVE NORMAL. HEADING FOR SECOND OR THIRD WARMEST ON
RECORD. WARMEST WAS 70.8 IN 1991. THEN 69.2 2004.
FOR ALLENTOWN...PERIOD OF RECORD (POR) BACK TO 1922. PROJECTING
65.9 OR ABOUT 6 DEGREES ABOVE NORMAL WHICH WOULD BE 4TH-5TH
WARMEST ON RECORD. 1991 WAS THE WARMEST WITH 67.2, FOLLOWED BY
2012 66.1, THEN 1944 WHEN MAY AVERAGED 66.0 AND FINALLY THE 2004
65.9 DEGREE AVG. THE NEXT WARMEST WAS 65.3 IN 1939.
THE FOLLOWING WAS POSTED BECAUSE ITS LIKELY THAT WE WILL
EXPERIENCE OUR FIRST 90 IN PHILADELPHIA BY THE MIDDLE OF NEXT
WEEK, AND POSSIBLY A HEAT WAVE.
NORMAL FIRST DATE OF 90 OR HIGHER.
PHILADELPHIA MAY 29
ALLENTOWN MAY 30
WILMINGTON JUNE 4
ATLANTIC CITY JUNE 11.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EDT SATURDAY FOR
ANZ450>453.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ454-
455.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ430-431.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...DRAG
SHORT TERM...DRAG
LONG TERM...GORSE
AVIATION...DRAG/GORSE
MARINE...DRAG/GORSE 627A
FIRE WEATHER...
RIP CURRENTS...
CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
605 AM EDT FRI MAY 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION LATER THIS AFTERNOON, THEN HIGH
PRESSURE BUILDS IN SATURDAY BEFORE SHIFTING OFFSHORE SATURDAY NIGHT
AND SUNDAY. A WARM FRONT IS FORECAST TO LIFT NORTH ACROSS OUR AREA
DURING MONDAY. A COLD FRONT IS THEN ANTICIPATED TO REMAIN WELL TO
OUR NORTH AND WEST WEDNESDAY AND THURSDAY AS HIGH PRESSURE REMAINS
ANCHORED IN THE WESTERN ATLANTIC.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY...SUNNY THIS MORNING THEN PARTLY SUNNY THIS AFTN AS A BAND
OF MODEST INSTABILITY CLOUDINESS AHEAD OF A CFP PASSES SEWD
THROUGH THE AREA WITH DECENT TOTAL TOTALS BUT ALMOST ZERO MLCAPE
(PROBABLY NOT ENOUGH MOISTURE FOR ANYTHING OTHER THAN A POSSIBLE
HIGH BASED SPRINKLE OR .01 SHOWER WITH GUSTY NORTHWEST WINDS TO
35KT). WE NOTED SUPPORT FOR THIS IN THE 00Z/22 NSSL WRF AND SPC
WRF. THE HRRR NOW HAS A GROUP OF SHOWERS RUNNING ESEWD THROUGH E
CENTRAL PA AND CENTRAL NJ IN THE 20-23Z TIME FRAME.
INCREASINGLY GUSTY WEST WINDS AHEAD OF THE COLD FRONT WITH 20 MPH
THIS MORNING AND 28-38 MPH BY MID AFTN. THE WSHIFT TO NNW ARRIVES
VCNTY I-80 IN THE 6P TIME FRAME (WHICH IS REALLY THIS EVENING-
EARLY TONIGHT).
TEMPS REBOUND AFTER YDYS 12 TO 18 BELOW NORMAL MAX TEMPS WITH THIS
AFTNS TEMPS ABOUT 15-20 DEGREES WARMER COMPARED TO THURSDAY AFTN
(NEAR NORMAL MAX`S).
FORECAST GENERATED GENERALLY FROM A 5050 BLEND OF 00Z/22 NCEP MOS
GUIDANCE (GFS/NAM).
CONFIDENCE: ABOVE AVERAGE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
CLEAR AND TURNING CHILLY AS THE CFP NEAR I-80 (NE PA/NNJ) IN THE
6P TIME FRAME SLIPS DOWN TO VCNTY KACY-KPHL AROUND 11P WITH A
PERIOD OF GUSTY NORTH-NORTHWEST WINDS OF 20-25 MPH EXPECTED EARLY
AT NIGHT THEN DECOUPLING-RAPIDLY DIMINISHING WIND LATE AS TEMPS
FALL RAPIDLY.
WILL CONTINUE A TOUCH OF SCT FROST FROM WARREN-SUSSEX COUNTIES IN
NW NJ INTO MONROE AND CARBON COUNTIES OF NE PA. JUST NOT ENOUGH
COVERAGE EXPECTED FOR A FROST ADVY. ALSO WITH FULL GREENUP, PROBABLY
ENOUGH LEAF COVER TO PREVENT MUCH DAMAGE. STILL, CANT BE ABSOLUTELY
SURE AND SO PATCHY FROST IS IN THE FCST AND POSSIBLE SPS MATERIAL
LATER TODAY FOR THOSE LOCATED IN SUCH PLACES AS WALPACK, PEQUEST,
THE TYPICALLY COLDEST LOW LYING AREAS IN THE NW FRINGE OF OUR
FORECAST AREA.
A BIT OF HIGH THIN CIRRUS POSSIBLE TOWARD SUNRISE SATURDAY?
FCST GENERALLY FROM A 5050 BLEND OF 00Z/22 NCEP MOS GUIDANCE
(GFS/NAM).
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF A CLOSED LOW MOVING FROM NORTHERN
NEW ENGLAND TO THE CANADIAN MARITIMES SATURDAY. THIS IS DUE TO
ENERGY STARTING TO EJECT INTO THE CENTRAL AND SOUTHERN PLAINS, WHICH
WILL ALSO BUILD A RIDGE FROM FLORIDA NORTHWESTWARD INTO THE MIDWEST
SATURDAY INTO MONDAY. THE RIDGE STRENGTHENS SOME AS IT SHIFTS
EASTWARD MONDAY AND TUESDAY, HOWEVER IT SHOULD THEN START TO FLATTEN
SOME ON ITS NORTHERN SIDE FROM ABOUT TUESDAY ONWARD. THE MAIN
FEATURE IS A FRONTAL BOUNDARY THAT SLIDES ACROSS THE NORTHEAST BUT
THIS THEN LIFTS BACK NORTHWARD AS A WARM FRONT MONDAY. IT LOOKS TO
TURN RATHER WARM TO EVEN HOT NEXT WEEK AS THE UPPER-LEVEL RIDGE IS
IN PLACE DESPITE IT GRADUALLY SHIFTING MORE OFFSHORE WITH TIME. WE
USED A MODEL BLEND FOR SATURDAY THROUGH MONDAY, THEN THE 00Z WPC
GUIDANCE WITH CONTINUITY THEREAFTER. SOME TWEAKS WERE THEN MADE
FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES.
FOR SATURDAY...A CHILLY START /PATCHY FROST UP NORTH/, OTHERWISE
HIGH PRESSURE STARTS TO SHIFT OFFSHORE AT NIGHT AS RIDGING BUILDS TO
OUR WEST. THE AIRMASS WILL BE COOL, THEREFORE HIGHS SHOULD BE IN THE
60S TO ABOUT 70 DEGREES ACROSS THE REGION. DUE TO HIGH PRESSURE IN
PLACE, LESS WIND IS EXPECTED COMPARED TO FRIDAY.
FOR SUNDAY AND MONDAY...A RIDGE TO OUR WEST WILL GRADUALLY BUILD
EASTWARD. SOME ENERGY SLIDING SOUTHEASTWARD ACROSS NORTHERN NEW
ENGLAND WILL DROP A FRONTAL BOUNDARY INTO OUR AREA SUNDAY NIGHT.
THIS BOUNDARY GENERALLY LOOKS TO BE ON THE WEAK SIDE, HOWEVER IT
COULD BE ACTIVATED MONDAY AS IT LIFTS NORTHWARD AS A WARM FRONT. AS
THE RIDGE BUILDS, OUR AREA IS STILL WITHIN THE NORTHWESTERLY FLOW
ALOFT. THE LOW-LEVEL FLOW IS FORECAST TO BE SOUTHWESTERLY, AND THE
COMBINATION OF WAA AND SOME FRONTAL LIFT AIDED BY SOME SHORT WAVE
ENERGY ALONG THE FRONT SHOULD PRODUCE SOME CONVECTION ON MONDAY. IT
APPEARS THAT THE BULK OF THE WAA/LIFT IS AIMED UP THE OHIO VALLEY
AND ACROSS THE GREAT LAKES. WE WILL NEED TO WATCH THIS THOUGH AS
SOME CONVECTION COULD SLIP INTO OUR AREA FROM THE WEST/NORTHWEST,
ESPECIALLY THE NORTHERN HALF, DURING MONDAY BEFORE THE RIDGE AXIS
REACHES OUR CWA. THE AMOUNT OF INSTABILITY WILL BE KEY AS WE
CONTINUE TO RECOVER FROM A RATHER DRY AIRMASS THAT IS IN PLACE PRIOR
TO MONDAY. OVERALL, CONVECTION MAY PRODUCE AT LEAST LOCALLY HEAVY
DOWNPOURS MONDAY. A MUCH WARMER AIRMASS IS EXPECTED TO OVERSPREAD
THE AREA ESPECIALLY MONDAY AS AN EXPANDING WARM SECTOR MOVES NORTH,
AND SOME INCREASE IN THE DEW POINTS WILL ALSO OCCUR.
FOR TUESDAY AND WEDNESDAY...WE ARE EXPECTED TO BE IN THE WARM SECTOR
DURING THIS TIME FRAME AS A SHORT WAVE ALOFT AND SURFACE LOW TRACKS
TO OUR NORTH, WHICH WILL FLATTEN THE RIDGE SOME. WHILE THE SURFACE
COLD FRONT IS CURRENTLY FORECAST TO STAY WELL TO OUR NORTH AND WEST,
SOME CONVECTION CANNOT BE RULED OUT. THIS APPEARS TO BE MAINLY
FOCUSED NEAR A LEE SIDE TROUGH IN THE PRESENCE OF A WARM/HOT AND
INCREASINGLY HUMID AIRMASS. GIVEN THE PRESENCE OF THE RIDGE AND THE
NORTHWESTERLY FLOW ALOFT BREAKING DOWN ACROSS OUR AREA, ANY
CONVECTION COULD BE SLOW MOVING WHICH WOULD RESULT IN LOCALLY HEAVY
RAIN. AS OF NOW, THE WESTERN ZONES HAVE A HIGHER CHC OF CONVECTION
GIVEN THE FORECAST PLACEMENT OF THE RIDGE AND ALSO A LEE SIDE
TROUGH. SOME PLACES ARE FORECAST TO REACH 90 DEGREES EACH AFTERNOON.
THE AFTERNOON HEAT INDICES ARE FORECAST TO BE CLOSE TO 95 DEGREES
ESPECIALLY WEDNESDAY AFTERNOON FOR THE URBANIZED AREAS OF THE
PHILADELPHIA METRO. IT SHOULD BE COOLER ALONG THE COAST DUE TO A
SOUTHERLY FLOW.
FOR THURSDAY...IT LOOKS TO BE A REPEAT OF THE PREVIOUS TWO DAYS AS
WE REMAIN IN THE WARM SECTOR, MEANWHILE A COLD FRONT SLOWLY SAGS
SOUTHEASTWARD ACROSS THE GREAT LAKES. SOME OF THE GUIDANCE IS FASTER
WITH THIS FRONT, HOWEVER WE WENT WITH THE WPC TIMING. ONCE AGAIN A
WARM TO EVEN HOT DAY IS ANTICIPATED, ALTHOUGH IT MAY BE A LITTLE
COOLER AS THE RIDGE WEAKENS SOME. SINCE A SOUTHERLY FLOW IS
FORECAST, IT SHOULD BE COOLER ALONG THE COAST. SOME MAINLY AFTERNOON
AND EVENING CONVECTION IS POSSIBLE ESPECIALLY INLAND, PROBABLY
FOCUSED ALONG A LEE SIDE TROUGH.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...MOSTLY VFR PRIOR TO 12Z WITH A LIGHT W-NW WIND. ANY REMAINING
MVFR FOG SE NJ SOON DISSIPATES. THEN AFTER 12Z...VFR CLEAR BECOMING
SCT-BKN AOA 6000 FT THIS AFTN WITH THE SLIGHT CHC OF A WLY 38KT
GUSTY SPRINKLE OR LIGHT SHOWER AHEAD OF A COLD FRONT. GENERALLY
GRADIENT WLY GUSTS 20 KT THIS MORNING INCREASE TO 25-33 KT THIS
AFTN.
TONIGHT...VFR CLEAR. THIN CIRRUS POSSIBLE TOWARD SUNRISE SATURDAY.
WSHIFT TO 20-25KT GUSTY NNW THIS EVENING FROM NORTH TO SOUTH, FIRST
NEAR I-80 AROUND 00Z REACHING KPHL/KACY AROUND 03-05Z.
CONFIDENCE: ABOVE AVERAGE.
OUTLOOK...
SATURDAY...VFR. NORTHWEST WINDS AROUND 10 KNOTS, BECOMING WEST-
SOUTHWEST DURING THE AFTERNOON.
SUNDAY...VFR. SOUTHWEST WINDS 10 TO 15 KNOTS, THEN DIMINISHING SOME
AT NIGHT.
MONDAY AND TUESDAY...MAINLY VFR. SOME SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ESPECIALLY DURING MONDAY. SOUTHWEST WINDS MAINLY AROUND
10 KNOTS.
&&
.MARINE...
SAFE BOATING WEEK CONCLUDES TODAY. OUR FINAL PUBLIC INFORMATION
STATEMENT FOR THIS SEASON POSTED AT 408 AM WITH THE SOCIAL MEDIA
POST AROUND 8AM. I DID GO AHEAD AND ADD THE NEW USCG SAFETY APP TO
MY SMART PHONE, JUST IN CASE IT COMES IN HANDY VIA MARINE RELATED
TALKS/INTERVIEWS.
THE FORECAST...
SCA VCNTY 44009 EARLY TODAY WITH SEAS NOW RESPONDING.
WINDS ON DELAWARE BAY UP A LITTLE MORE THAN ANTICIPATED AND IF
THIS CONTINUES MAY START THE SCA BACK TO WHERE WE HAD IT, THIS
MORNING. RIGHT NOW, NO CHANGE.
OTRW...SCA ALL OTHER WATERS WITH THE PRIMARY THREAT PERIOD OF 2P-
MIDNIGHT. WLY WIND GST 25-30 KT THIS AFTN AHEAD OF A COLD FRONT
THEN JUST AFT OF THE COLD FRONTAL PASSAGE WIND SHIFT TO NNW THIS
EVENING. STRONGEST WIND NEAR THE SHORE WHERE ITS WARMER AND BETTER
MIXING-MOMENTUM TRANSFER.
WINDS DIMINISH TOWARD SUNRISE SATURDAY.
OUTLOOK...
SATURDAY AND SUNDAY...NORTHWEST WINDS DIMINISHING SATURDAY AND THEN
BECOMING SOUTHWEST TOWARD EVENING. THE SOUTHWESTERLY FLOW CONTINUES
SUNDAY AND SHOULD INCREASE SOME, HOWEVER OVERALL THE CONDITIONS
SHOULD BE BELOW ADVISORY CRITERIA.
MONDAY AND TUESDAY...A SOUTHWESTERLY FLOW OF 10-20 KNOTS IS
ANTICIPATED WITHIN A WARM/HOT AIRMASS. THIS MAY RESULT IN THE HIGHER
WINDS CLOSER TO THE COAST. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ESPECIALLY MONDAY. SEAS AT OR BELOW 4 FEET, ALTHOUGH THESE
MAY NEAR 5 FEET TUESDAY ACROSS THE NORTHERN COASTAL WATERS.
&&
.FIRE WEATHER...
WIND GUSTS OF 25 TO 35 MPH ARE EXPECTED THIS AFTERNOON AND RELATIVE
HUMIDITY VALUES SHOULD FALL INTO THE 20 TO 30 PERCENT RANGE IN
MUCH OF OUR REGION AT THAT TIME. HOWEVER, YESTERDAYS RAINFALL IS
FORECAST TO KEEP FINE FUEL MOISTURE FROM FALLING BELOW CRITICAL
LEVELS AT THOSE LOCATIONS WHERE THE GREEN-UP IS NOT COMPLETE, MOST
NOTABLY THE PINE BARRENS. AS A RESULT, WE ARE NOT ANTICIPATING ANY
FIRE WEATHER ISSUES FOR FRIDAY.
&&
.RIP CURRENTS...
POTENTIAL HEAT WAVE NEXT WEEK. THIS PLUS WATER TEMPS CONTINUING ABOVE
NORMAL IS NOT GOOD FOR SAFETY. ONCE IT TURNS HOT AND BEACHES ARE
UNGUARDED, SWIMMERS MAY TAKE CHANCES AT UNGUARDED LOCATIONS. BE SMART
ABOUT ANY SWIMMING EARLY THIS SEASON.
RIP CURRENT AWARENESS WEEK FOR MT HOLLY IS JUNE 7-13 WITH PSAS
VIA PUBLIC INFORMATION STATEMENTS, SOCIAL MEDIA, NOAA WEATHER
RADIO AND ANY MEDIA INTERVIEWS DESIRED (CONTACT OFFICE).
FOR RIP CURRENTS: DESPITE ANTICIPATED PROJECTIONS OF LOW OR
MODERATE RISK THROUGH THE MEMORIAL DAY WEEKEND, EARLY SEASON
FATALITIES OCCUR WHEN SWIMMING AT UNGUARDED TIMES/LOCATIONS.
WEAKER SWIMMERS OR SWIMMING IN AREAS WHERE RIP CURRENTS ARE
STRONGER (JETTIES) CAN QUICKLY BECOME LIFE THREATENING. WHEN
TRAINED LIFEGUARDS ARE NOT NEARBY, TIMELY RESCUE IS MUCH LESS
LIKELY. LETS GET THROUGH THE MONTH OF MAY WITH ALL SWIMMERS SAFE!
PLEASE BROADCAST THIS MESSAGE: FOR ULTIMATE SAFETY, ALWAYS SWIM
IN THE PRESENCE OF LIFE GUARDS! THANK YOU!
&&
.CLIMATE...
**LITTLE DOUBT THAT A TOP 10 WARMEST WILL OCCUR IN LARGE PORTIONS
OF OUR FORECAST AREA**
THE FIRST 21 DAYS OF MAY IN OUR FORECAST AREA WERE AVERAGING
ABOUT 6 DEGREES ABOVE NORMAL.
RUNNING THE NUMBERS FROM THIS MORNINGS 330AM FCST THROUGH THE
28TH AND THE 00Z/22 FTPRHA (GFS MOS) FOR THE LAST 3 DAYS BEYOND
OUR WFO RESPONSIBILITY (29-31) WE FIND THE FOLLOWING.
FOR PHILADELPHIA...PERIOD OF RECORD (POR) BACK TO 1874.
PROJECTING A MONTHLY AVERAGE TEMPERATURE OF 69 TO 70, AT LEAST 5
TO 6 DEGREES ABOVE NORMAL. HEADING FOR SECOND OR THIRD WARMEST ON
RECORD. WARMEST WAS 70.8 IN 1991. THEN 69.2 2004.
FOR ALLENTOWN...PERIOD OF RECORD (POR) BACK TO 1922. PROJECTING
65.9 OR ABOUT 6 DEGREES ABOVE NORMAL WHICH WOULD BE 4TH-5TH
WARMEST ON RECORD. 1991 WAS THE WARMEST WITH 67.2, FOLLOWED BY
2012 66.1, THEN 1944 WHEN MAY AVERAGED 66.0 AND FINALLY THE 2004
65.9 DEGREE AVG. THE NEXT WARMEST WAS 65.3 IN 1939.
THE FOLLOWING WAS POSTED BECAUSE ITS LIKELY THAT WE WILL
EXPERIENCE OUR FIRST 90 IN PHILADELPHIA BY THE MIDDLE OF NEXT
WEEK, AND POSSIBLY A HEAT WAVE.
NORMAL FIRST DATE OF 90 OR HIGHER.
PHILADELPHIA MAY 29
ALLENTOWN MAY 30
WILMINGTON JUNE 4
ATLANTIC CITY JUNE 11.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EDT SATURDAY FOR
ANZ450>453.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ454-
455.
SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EDT TONIGHT
FOR ANZ430-431.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...DRAG 605
SHORT TERM...DRAG
LONG TERM...GORSE
AVIATION...DRAG/GORSE 605
MARINE...DRAG/GORSE 605
FIRE WEATHER...605
RIP CURRENTS...605
CLIMATE...605
AREA FORECAST DISCUSSION
NWS LINCOLN IL
944 AM CDT FRI MAY 22 2015
.UPDATE...
ISSUED AT 940 AM CDT FRI MAY 22 2015
TEMPERATURES ARE RECOVERING QUICKLY WITH ABUNDANT SUNSHINE...BUT
CIRRUS CLOUDS ARE STARTING TO CREEP INTO THE FAR WESTERN CWA.
HAVE MADE SOME TWEAKS TO THE HIGH TEMPERATURES...GOING WITH MID
70S EVERYWHERE. WILL NEED TO WATCH THIS DURING THE AFTERNOON...AS
THE HRRR IS HINTING AT UPPER 70S OVER THE SOUTHWEST. HOWEVER...THE
HIGH CLOUDS WILL BE THICKENING UP DURING THE AFTERNOON...SO THIS
MAY HELP KEEP TEMPERATURES IN CHECK.
&&
.SHORT TERM...(TODAY)
ISSUED AT 331 AM CDT FRI MAY 22 2015
A BEAUTIFUL SPRING DAY EXPECTED TODAY ACROSS IL WITH A FAIR AMOUNT
OF SUNSHINE AND FAIRLY LIGHT WINDS AND MILD HIGHS IN THE MID 70S. A
WEAK FRONTAL BOUNDARY NEAR I-88 IN NORTHERN IL EARLY THIS MORNING
WILL DROP SOUTHWARD ACROSS CENTRAL IL DURING THIS MORNING AND
THROUGH SOUTHEAST IL DURING THE AFTERNOON. LITTLE IF ANY LIFT OR
MOISTURE TO WORK WITH SO EXPECT THIS FRONT TO SHIFT BE ACCOMPANIED
BY A WEAK WIND SHIFT FROM THE SW TO THE NW. CIRRUS CLOUDS TO
INCREASE FROM THE WEST LATER THIS MORNING AND AFTERNOON AS SUNNY
SKIES THIS MORNING BECOME PARTLY TO MOSTLY SUNNY IN THE AFTERNOON.
NUDGED HIGHS UP SLIGHTLY TODAY INTO THE MID 70S ACROSS MUCH OF THE
AREA WITH AREAS FROM I-74 NE SLIGHTLY COOLER.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 331 AM CDT FRI MAY 22 2015
NICE WEATHER TO CONTINUE ACROSS IL DURING THE FIRST HALF OF THE
MEMORIAL DAY WEEKEND AS DRY CONDITIONS PERSIST THROUGH SATURDAY.
HIGH PRESSURE DRIFTS SE FROM LAKE SUPERIOR INTO THE MID ATLANTIC
STATES SATURDAY WHILE UPPER LEVEL RIDGE NOSES INTO THE MS RIVER
VALLEY. THIS TO MAINTAIN DRY CONDITIONS TONIGHT AND SATURDAY ACROSS
CENTRAL AND SOUTHEAST IL. MID AND HIGH CLOUDS CONTINUE TO INCREASE
TONIGHT AND SATURDAY WITH SKIES TRENDING TOWARD PARTLY TO MOSTLY
CLOUDY. LOWS TONIGHT IN THE LOW TO MID 50S WITH HIGHS SAT IN THE MID
TO UPPER 70S.
LARGE UPPER LEVEL TROF/LOW DIGGING OVER THE ROCKIES DURING THIS
WEEKEND TO EJECT SHORT WAVES NE INTO THE CENTRAL PLAINS SAT NIGHT
AND INTO THE UPPER MS RIVER VALLEY ON SUNDAY. SURFACE LOW PRESSURE
EMERGES OVER THE CENTRAL PLAINS SUNDAY AND LIFTS UP INTO THE UPPER
MS RIVER VALLEY AND NORTHERN PLAINS MONDAY. A WARM FRONT TO LIFT
NORTHWARD ACROSS CENTRAL IL SUNDAY MORNING. THIS TO BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO WESTERN AREAS OVERNIGHT SAT NIGHT
AND THEN LIKELY CHANCES WEST OF I-57 SUNDAY AND SUNDAY NIGHT AND 40-
50% CHANCE OVER EASTERN IL SUNDAY FROM I-57 EAST. MORE HUMID ON
SUNDAY AS WARM FRONT LIFTS NORTH WITH SOUTHERLY FLOW DEVELOPING AS
DEWPOINTS ELEVATE INTO THE MID 60S BY SUNDAY AFTERNOON WITH HIGHS IN
THE UPPER 70S CENTRAL IL AND NEAR 80F IN SOUTHEAST IL. SPC KEEPS
MARGINAL RISK OF SEVERE STORMS SW OF CENTRAL IL SUNDAY AFTERNOON AND
EVENING WHERE BETTER INSTABILITY WILL BE DURING PEAK HEATING.
EXTENDED MODELS CONTINUE AN UNSETTLED WEATHER PATTERN THROUGH MUCH
OF NEXT WORK WEEK WITH DAILY CHANCES OF SHOWERS AND THUNDERSTORMS AS
FRONTAL BOUNDARY STAYS NW OF IL THROUGH AT LEAST WED AND POSSIBLY
LONGER. CONTINUE LIKELY CHANCES OF SHOWERS AND THUNDERSTORMS MONDAY
WITH HIGHS AROUND 80F AND DEWPOINTS IN THE MID TO UPPER 60S. BREEZY
CONDITIONS EXPECTED MONDAY SIMILAR TO SUNDAY IN THE WARM SECTOR.
CONTINUED GOOD CHANCE OF SHOWERS AND THUNDERSTORMS DURING MIDDLE OF
NEXT WEEK AND WARM HIGHS IN THE LOWER 80S AND LOWS IN THE MID TO
UPPER 60S. CPC 8-14 DAY OUTLOOK FROM MAY 29 THRU JUNE 4 CONTINUES 40-
50% CHANCE OF ABOVE NORMAL TEMPERATURES AND PRECIPITATION. SO A
WARM AND WET PATTERN LOOKS TO CONTINUE INTO THE FIRST WEEK OF
JUNE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 652 AM CDT FRI MAY 22 2015
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES NEXT 24HRS AS
PREDOMINANT SUBSIDENCE RESIDES OVER CENTRAL IL WITH HIGH PRESSURE
BUILDING INTO THE AREA. WINDS WILL BE VARIABLE...THEN BECOME NE AT
4-8 KTS AFTER A WEAK DRY COLD FRONT PUSHES THROUGH THE AREA FROM
THE NORTH.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...07
LONG TERM...07
AVIATION...AUTEN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
639 AM EDT FRI MAY 22 2015
.UPDATE...
ISSUED AT 630 AM EDT FRI MAY 22 2015
BASED ON THE LATEST OBS AND WEB CAMERA IMAGES...HAVE BEEFED UP THE
FOG FURTHER IN THE GRIDS ADDING DENSE TO THE VALLEYS AND SOME
RIDGES. AS A RESULT...ALSO ISSUED AN SPS FOR PATCHY DENSE FOG THAT
NOW RUNS THROUGH 9:30 AM. SENT OUT AN UPDATED SET OF ZONES WITH A
PRE FIRST PERIOD FOR THE FOG. FINALLY...FOR THE GRIDS...TWEAKED
THE NEXT SEVERAL HOURS T/TD GRIDS PER THE LATEST OBS AND TRENDS.
THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 22 2015
07Z SFC ANALYSIS SHOWS HIGH PRESSURE SETTLING INTO THE MID
MISSISSIPPI AND TENNESSEE VALLEYS WITH LOW PRESSURE TO THE NORTH
AND SOUTHEAST. THIS HAS HELPED TO CLEAR THE SKIES THROUGH EASTERN
KENTUCKY AS A NARROW BAND OF LOWER CLOUDS IS HOLDING ON NEAR THE
VIRGINIA BORDER. PATCHY FOG HAS DEVELOPED IN THE VALLEYS EARLY
THIS MORNING IN THE WAKE OF THE CLEARING AND LEFT OVER GROUND
MOISTURE. IN ADDITION...A FEW PATCHES OF DENSE FOG ARE NOTED IN
THE CUMBERLAND VALLEY AND ALSO ON SOME OF THE RIDGES. WILL MONITOR
THIS VIA THE OBS AND WEB CAMS FOR A POSSIBLE SPS OR NPW THIS
MORNING. AT A MINIMUM...THE PATCHES OF DENSE FOG WILL BE
HIGHLIGHTED IN THE MORNING PORTION OF THE FORTHCOMING HWO.
READINGS ARE RATHER CHILLY THIS MORNING...MAINLY IN THE LOWER AND
MIDDLE 40S WHILE DEWPOINTS ARE GENERALLY A DEGREE OR SO LOWER THAN
DRY BULB TEMPS AMID LIGHT NORTHWEST WINDS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH A DEPARTING TROUGH TO
THE NORTHEAST EARLY TODAY FOLLOWED BY RISING HEIGHTS AS A RIDGE
DEVELOPS OVER THE SOUTHEAST PART OF THE NATION. A BAND OF WEAK
MID LEVEL ENERGY WILL LIFT THROUGH KENTUCKY AND INTO THE OHIO
VALLEY FRIDAY NIGHT DURING THIS TRANSITION...BEFORE THE RIDGE
SHARPENS OVER EAST KENTUCKY ON SATURDAY. GIVEN THE MODEL AGREEMENT
HAVE FAVORED THE NAM12 AND HRRR FOR WX DETAILS DUE TO THEIR
HIGHER RESOLUTION.
SENSIBLE WEATHER WILL FEATURE A PLEASANT 48 HOURS AND BEYOND...
ONCE THIS MORNING/S VALLEY FOG...LOCALLY DENSE...BREAKS UP BY 10
AM. TEMPS WILL BE A BIT WARMER EACH DAY WITH A DECENT RIDGE
VALLEY TEMPERATURE SPLIT EXPECTED TONIGHT...BUT MILDER FOR MOST
PLACES THAN EARLY THIS MORNING. HIGH CLOUDS WILL MOVE IN LATER
TODAY AND CONTINUE TO BUILD ON SATURDAY AS A MOSTLY DRY FRONT
SETTLES INTO THE AREA. A STRAY SHOWER CANNOT BE RULED OUT TONIGHT
TO THE NORTHEAST OF THE AREA AS THAT FRONT INITIALLY APPROACHES
BEFORE THE RIDGE ALOFT BUILDS SIGNIFICANTLY OVER THE CWA BY
SATURDAY MORNING.
USED THE SHORTBLEND AS A STARTING POINT FOR THE T/TD AND WIND
GRIDS THROUGH TODAY BEFORE FOLLOWING TO THE SUPERBLEND. DID MAKE
SOME MODERATE TERRAIN BASED CHANGES TO THE LOW TEMPERATURES
TONIGHT. AS FOR POPS...KEPT THEM MINIMAL THROUGH THE PERIOD...IN
LINE WITH MOS GUIDANCE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 AM EDT FRI MAY 22 2015
THE MODELS ARE IN PRETTY GOOD AGREEMENT TO BEGIN THE EXTENDED
PERIOD...WITH A RIDGE OF HIGH PRESSURE BRINGING WARM AND DRY WEATHER
TO THE AREA SATURDAY NIGHT THROUGH LATE IN THE DAY ON MONDAY. IT
LOOKS AS IF THE OHIO AND TENNESSEE VALLEY REGIONS WILL BE FIRMLY
ENTRENCHED IN THE WARM SECTOR OF AN APPROACHING MID LATITUDE
CYCLONE. THE WARM WEATHER WOULD BE IN RESPONSE TO PERSISTENT
SOUTHERLY WINDS SOUTH OF A STRONG NORTHWARD MOVING WARM FRONT.
SHOULD THE MODELS HOLD TRUE...WE WOULD SEE THE RIDGE BEGIN TO BREAK
DOWN MONDAY AFTERNOON AND EVENING...AS A LARGE STORM SYSTEM
APPROACHES FROM THE WEST. THE FIRST PRECIPITATION IS FORECAST TO
MOVE INTO THE AREA BY EARLY MONDAY MORNING AS WARM MOIST AIR OFF THE
GULF OF MEXICO BEGINS TO INTERACT WITH WHAT LOOKS LIKE A PRE FRONTAL
TROUGH. THE PRECIPITATION WILL GRADUALLY INCREASE IN COVERAGE MONDAY
AND MONDAY NIGHT AS THE FRONT INCHES TOWARD THE AREA. THE MODEL DATA
SUGGESTS THAT THERE WILL BE A GOOD CHANCE OF RAIN FROM MONDAY NIGHT
THROUGH EARLY THURSDAY AFTERNOON...AS THE AFOREMENTIONED COLD FRONT
MOVES SLOWLY ACROSS THE REGION...AND PERHAPS EVEN STALLS OUT FOR A
TIME. THE MEMORIAL DAY HOLIDAY AT THIS TIME LOOKS LIKE IT WILL BE
WARM WITH ONLY A SMALL CHANCE OF RAIN ACROSS THE AREA.
TEMPERATURES DURING THE EXTENDED WILL LIKELY BE WELL ABOVE NORMAL
FOR THE TIME OF YEAR...DUE TO PERSISTENT SOUTHERLY FLOW AND
SUBSIDENCE WARMING ASSOCIATED WITH THE RIDGE OF HIGH PRESSURE
MENTIONED EARLIER IN THIS DISCUSSION. HIGHS ARE FORECAST TO TOP OUT
IN THE LOWER 80S THROUGH MID WEEK...WITH OVERNIGHT LOWS IN THE
60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 640 AM EDT FRI MAY 22 2015
DUE TO DAMP GROUNDS AND CLEARING SKIES OCCASIONAL LIFR OR LOWER
VIS FROM FOG WILL BE POSSIBLE AT ALL SITES EXCEPT SYM THROUGH THE
EARLY MORNING HOURS. ONCE THE PATCHY DENSE FOG BURNS OFF BY
14Z...VFR CONDITIONS ARE EXPECTED THROUGH THE BULK OF TONIGHT...
THOUGH SOME PATCHY FOG WILL AGAIN BE POSSIBLE AT THE LOWER TAF
SITES BY DAWN SATURDAY. WINDS WILL BE LIGHT FROM THE NORTHWEST
THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
929 AM CDT FRI MAY 22 2015
.UPDATE...
COLD FRONT HAS PUSHED OFF THE SOUTHEAST LOUISIANA COAST TAKING THE
MORE SIGNIFICANT SHOWERS AND THUNDERSTORMS SOUTH WITH THE
BOUNDARY. AN ELEVATED BOUNDARY WITH ISENTROPIC LIFT WAS THE FOCUS
FOR SOME SHOWERS IN AND NEAR THE MISSISSIPPI SOUND. THE FRONTAL
BOUNDARY WILL RETURN BACK NORTH AS A WARM FRONT LATER TODAY AND
ESPECIALLY TOMORROW...HOWEVER SOME OF THE MODELS LIKE THE GFS
APPEAR TOO AGGRESSIVE BRINGING THE FRONT BACK NORTH TO THE I-10/12
CORRIDOR LATE THIS AFTERNOON AND EVENING GIVEN THE FACT THAT THE
DEWPOINTS ARE STILL DROPPING IN SOUTHEAST LOUISIANA COASTAL AREAS.
A BLEND OF THE HRRR AND HIRES WRF MODELS SUGGEST THE ONLY
LOCATIONS THAT MAY SEE SHOWERS AND POSSIBLY A FEW THUNDERSTORMS
WILL BE ALONG THE SOUTHEAST LOUISIANA COAST LATER THIS
AFTERNOON...AND A BLEND OF THE GFS,,,NAM...SREF...AND ECMWF ONLY
SHOW SOME LOW RAIN CHANCES A BIT FURTHER NORTH ALLOWING FOR SOME
SHALLOW ELEVATED CAPE TAKING ADVANTAGE OF SOME ISENTROPIC
LIFT/WEAK WARM AIR ADVECTION OVER THE SHALLOW FRONTAL BOUNDARY.
GIVEN THESE FACTORS AND THOSE MENTIONED IN THE SOUNDING
DISCUSSION...HAVE CUT BACK THE AREAL COVERAGE OF THUNDER TODAY AND
LOWERED THE RAIN CHANCES IN MANY LOCATIONS.
22/TD
&&
.SOUNDING DISCUSSION...
REFRESHING BREEZES FROM THE NORTHEAST IN THE LOWEST 1500 FEET WERE
DELIVERING COOLER AND DRIER AIR TO MOST OF THE AREA THIS MORNING
WITH THE EXCEPTION OF LOUISIANA COASTAL PARISHES. THESE NORTHEAST
WINDS HAVE PUSHED THE FRONT JUST OFFSHORE WHERE THERE IS ONGOING
SCATTERED SHOWERS AND THUNDERSTORMS. THERE IS STILL QUITE A BIT OF
MOISTURE IN THE ATMOSPHERE WITH THE PRECIPITABLE WATER VALUE ABOVE
1.75 INCHES. ELEVATED TEMPERATURE INVERSION OF 5C CAPS OFF THE LOW
LEVEL COOLER AIR...WHICH ALONG WITH LIMITED INSTABILITY
/FORECAST CAPE AND LI/ SHOULD LIMIT COVERAGE OF SHOWERS AND
THUNDERSTORMS. WINDS ABOVE 1500 FEET HAVE A WESTERLY COMPONENT AND A
PEAK WIND SPEED OF 59 KNOTS WAS AT 43000 FEET.
12Z BALLOON INFO: A ROUTINE FLIGHT WITH THE ASCENT LASTING 92
MINUTES THIS MORNING. THE BALLOON TRAVELLED 20 MILES DOWNRANGE FROM
THE OFFICE BURSTING EAST OF STENNIS SPACE CENTER AT A HEIGHT OF 21
MILES ABOVE THE GROUND.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 435 AM CDT FRI MAY 22 2015/
SYNOPSIS...
SURFACE MAP REVEALED A STALLED FRONTAL BOUNDARY FROM SOUTH
CAROLINA COAST TO BIG BEND FLORIDA TO SOUTHEAST LOUISIANA COASTAL
WATERS TO SOUTH TEXAS. IN ADDITION...A 1023MB HIGH WAS LOCATED OF
THE MID SOUTH AND ABOUT A 4MB CHANGE FROM THE MCCOMB TO MS DELTA.
NORTH WINDS OF 5 TO 12 KNOTS WERE COMMON ACROSS THE FORECAST AREA
THIS MORNING. MORE SO...DEWPOINT READINGS RANGE FROM THE UPPER
50S OVER SOUTHWEST MS TO NEAR 70 NEAR MS DELTA. PRECIPITABLE
WATER VALUE PLOTS SHOWED A MOISTURE AXIS ALONG TEXAS AND LOUISIANA
COAST WITH VALUES OF 1.6 TO 1.75 INCHES. UPPER AIR CHARTS SHOWED A
LOW OVER SOUTH CALI...A HIGH OVER MEXICO...DIFFLUENT FLOW OVER
WEST TEXAS AND WEAK WEST FLOW OVER LOWER MISSISSIPPI VALLEY. 18
DISCUSSION...
MOISTURE AXIS WILL POOL ALONG THE COAST...WEST OF THE MISSISSIPPI
DELTA TO SOUTH CENTRAL LOUISIANA THIS MORNING THROUGH THIS
AFTERNOON. MID LAYER INSTABILITY IS PRESENT WITH THIS LAYER. AS A
RESULT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FORM IN THIS
GENERAL AREA. DRY AIR AND LESS MOISTURE WITH PW VALUES 1.4 TO 1.5
INCHES OVER MS COAST AND NORTH OF TIDAL LAKES WILL HAMPER
THUNDERSTORM DEVELOPMENT TODAY. COLD AIR ADVECTION WILL LOWER
1000-700MB FROM 3025M TO 2990M ACROSS NORTH ZONES AND 3020M TODAY.
THIS FEATURE ALONG WITH CLOUD COVER WILL HAMPER HIGH SUN ANGLE A
LITTLE BIT TO LOWER HIGHS ABOUT 4 TO 6 DEGREES TODAY. LOWER
DEWPOINTS AND LOWER THICKNESS WILL ALLOW EVENING AND NIGHT TIME
TEMPS ABOUT 6 TO 10 DEGREES FOR SOME LOCATIONS. THE ASSOCIATED
SURFACE HIGH WILL MOVE TO THE EAST COAST BY MIDDAY SATURDAY AND
YIELD A SOUTHEAST FLOW OVER THE PLAINS AND WEST PART OF THE LOWER
MISSISSIPPI VALLEY. HENCE...WEST ZONES WILL SEE INCREASE IN RAIN
CHANCES ON SATURDAY BUT DRY FOR MS COAST ON SATURDAY.
SUNDAY AND THE REST OF THE FORECAST PERIOD WILL HAVE A GOOD
CHANCE OF RAIN IN THE FORECAST. THE MAIN LOW WILL TRACK WEST
ACROSS THE ROCKIES SUNDAY AND OVER THE PLAINS MONDAY. MOISTURE
WILL POOL AHEAD OF THE TROUGH AXIS OVER THE SOUTHERN PLAINS. THE
CLOSE PROXIMITY AND OPEN GULF WILL YIELD LIKELY RAIN CHANCES EACH
AFTERNOON MONDAY THROUGH WEDNESDAY ACROSS THE NORTH AND WEST
ZONES. TROUGH WILL REMAIN OVER THE PLAINS BUT NOT AS SHARP LATTER
PART OF NEXT WEAK. MOISTURE WILL REMAIN ACROSS THE AREA.
THEREFORE...RAIN CHANCES WILL DECREASE BUT NOT MUCH FOR THURSDAY
AND FRIDAY OF NEXT WEEK. 18
AVIATION...
CEILINGS SHOULD REMAIN AT OR ABOVE 003 FOR ALL SITES. WILL ONLY SHOW
SMALL RESTRICTIONS DUE TO VIS THIS MORNING. SHOULD SEE MOST SITES
FREE OF ANY VCTS TODAY WITH THE EXCEPTION OF HUM AND POSSIBLY BTR.
WILL ONLY SHOW FOR HUM TODAY AS DRY AIR WILL BE VERY CLOSE TO BTR.
IF SOMETHING DEVELOPS AROUND BTR IT WILL BE TO THE WEST. CEILINGS
SHOULD STAY IN THE 020 AREA WITH SOME GROUPS OF 005 MOVING THROUGH
TONIGHT.
MARINE...COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS MORNING
AND STALL. AS THE FRONT ERODES...WINDS WILL BEGIN TO FRESHEN TO
AROUND 15 THEN 15-20KT BY SAT NIGHT OR SUN AHEAD OF THE NEXT SYSTEM
DEVELOPING IN THE OKLAHOMA/NEBRASKA AREA. THIS SYSTEM WILL NOT MAKE
MUCH PROGRESS EASTWARD BUT IT WILL BE ABLE TO KICK OUT A FEW
PREFRONTAL TROUGHS THAT WILL CARRY SH/TS INTO THE NORTHERN GULF BY
TUESDAY. MODERATE WINDS OUT OF THE SE WILL REMAIN THROUGH WED BEFORE
EASING BACK TO A MORE MANAGEABLE 10KT BY THE END OF THE WEEK.
DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
.DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 80 64 86 70 / 10 10 30 20
BTR 81 69 86 72 / 10 20 40 20
ASD 81 67 86 72 / 10 10 20 20
MSY 80 73 86 75 / 20 20 30 20
GPT 82 69 85 75 / 10 10 20 20
PQL 82 63 86 72 / 10 10 10 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
642 AM CDT FRI MAY 22 2015
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
HAVE LOW CONFIDENCE IN THE TAFS.
WIDESPREAD MVFR OR LOWER CONDITIONS WILL FORM AT ALL SITES BY 15Z.
THE WORST CONDITIONS WILL BE OVER WESTERN OKLAHOMA AND WESTERN
NORTH TEXAS WHERE A FEW SITES MAY DROP TO LIFR. SOME IMPROVEMENT
IS POSSIBLE AFTER 18Z...BUT DID NOT MENTION AS THIS IS UNLIKELY.
AREA OF RA/TSRA WILL AFFECT MOST TAF SITES THROUGH 17Z.
ADDITIONAL RA/TSRA ARE POSSIBLE AFTER 17Z...BUT DID NOT MENTION
EXCEPT NEAR KPNC...KWWR...AND KGAG AFTER 10Z WHERE CHANCES OF
OCCURRENCE ARE JUST HIGH ENOUGH TO JUSTIFY.
MBS
&&
.PREV DISCUSSION... /ISSUED 417 AM CDT FRI MAY 22 2015/
DISCUSSION...
HEAVY RAINFALL AND FLOODING ARE THE MAIN CONCERNS THIS HOLIDAY
WEEKEND. SEVERE THUNDERSTORM POTENTIAL SATURDAY AND SUNDAY ARE
ADDITIONAL CONCERNS.
THE BIGGEST CHANGE TO THE PREVIOUS FORECAST WAS TO EXPAND THE
FLASH FLOOD WATCH TO INCLUDE NORTHERN AND NORTHWESTERN OKLAHOMA.
LATEST MODELS...ESPECIALLY THE ECMWF...DEPICTED HIGHER
QPF/RAINFALL AMOUNTS IN THESE AREAS...GENERALLY 1 TO 4 INCHES...
LATE TONIGHT THROUGH MONDAY...SO BELIEVE THE FLASH FLOODING
POTENTIAL MAY BE INCREASING IN THESE LOCATIONS. THE REST OF THE
WATCH APPEARS TO BE IN GOOD SHAPE.
TODAY...BATCH OF ELEVATED SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE TO MOVE EAST ACROSS THE AREA...MAINLY THIS MORNING...
BRINGING GENERALLY 0.25 TO 0.50 INCHES OF RAINFALL. DUE TO LACK OF
INSTABILITY...NO STRONG OR SEVERE STORMS OR FLASH FLOODING ARE
EXPECTED WITH THIS ACTIVITY. THIS ACTIVITY WILL END WEST TO EAST
LATER THIS MORNING INTO THE AFTERNOON HOURS AND LATEST HRRR RUNS
MAY BE TO SLOW WITH THE PROGRESSION OF THIS RAIN. BELIEVE MOST
LOCATIONS WILL REMAIN MOSTLY CLOUDY AND DRY THIS AFTERNOON. DUE
TO CLOUD COVER...WENT TOWARDS THE COOLER SIDE OF MODEL GUIDANCE
FOR HIGHS. SOME PATCHY FOG MAY FORM IN WESTERN NORTH TEXAS AND
WESTERN OKLAHOMA TODAY AS LOW LEVELS MOISTEN. THE TRUE SURFACE
WARM FRONT IS EXPECTED TO STAY SOUTH OF THE AREA.
TONIGHT...MAINLY DRY CONDITIONS SHOULD OCCUR THROUGH MIDNIGHT
BEFORE RAIN CHANCES SLOWLY INCREASE. KEPT THE HIGHEST RAIN
CHANCES AFTER MIDNIGHT IN NORTHWESTERN OKLAHOMA. SEVERE POTENTIAL
AND HEAVY RAINFALL SEEM TO BE RATHER LOW TONIGHT IN THESE
LOCATIONS. WOULD NOT BE SURPRISED IF THERE WAS SOME FOG ACROSS THE
AREA...BUT DID NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE.
SATURDAY AND SATURDAY NIGHT...FLOODING CONCERNS WILL INCREASE AS
SHOWERS AND THUNDERSTORMS WITH HEAVY RAINFALL INCREASE IN
COVERAGE AND SPREAD EAST DURING THE DAY. THERE SEEMS TO BE A
SIGNAL FROM THE MODELS THAT NORTHWESTERN OKLAHOMA MAY HAVE THE
HIGHEST RAINFALL TOTALS DURING THE MORNING...SPREADING TO THE I-44
CORRIDOR AND POINTS SOUTHEAST BY SATURDAY NIGHT. KEPT HIGH RAIN
CHANCES IN THE FORECAST. PRECIPITABLE WATER VALUES ARE FORECAST TO
APPROACH NEARLY 2 INCHES WHICH WOULD BE NEAR RECORD LEVELS. VERY
HEAVY RAIN RATES OVER 2 INCHES PER HOUR ARE POSSIBLE AND WOULD
ONLY INCREASE FLASH FLOODING POTENTIAL.
IN REGARDS TO SEVERE POTENTIAL SATURDAY AND SATURDAY NIGHT...
BELIEVE THERE IS SOME POTENTIAL...BUT CONFIDENCE IN TIMING...
LOCATIONS...AND STORM MODE REMAIN LOW. MESOSCALE DETAILS WILL
DICTATE WHAT OCCURS. CLOUD COVER MAY LIMIT INSTABILITY.
HOWEVER...STRONG SHEAR INCLUDING THE LOW LEVELS AND ABUNDANT
MOISTURE MAY SUPPORT AT LEAST A LOW TORNADO THREAT. SOME DAMAGING
WINDS AND HAIL MAY OCCUR. STILL BELIEVE FLOODING AND POSSIBLE
TRAINING OF HEAVY RAINFALL WILL BE THE MAIN CONCERNS.
SUNDAY AND SUNDAY NIGHT...THE FLOODING AND HEAVY RAINFALL THREAT
WILL CONTINUE ACROSS THE AREA. WHAT HAPPENS ON SATURDAY WILL HAVE
A BIG INFLUENCE ON WHAT OCCURS SUNDAY AND SUNDAY NIGHT. GENERALLY
THINK THE HEAVIEST RAINFALL AXIS WILL SHIFT SOUTHEAST OF I-44.
SEVERE POTENTIAL REMAINS VERY UNCERTAIN AS CLOUD COVER AND RAIN
MAY STABILIZE THE AIR. HOWEVER...IF SOME CLEARING AND
DESTABILIZATION OCCURS...THE SEVERE WEATHER POTENTIAL WOULD
INCREASE CONSIDERABLY...ESPECIALLY AS SHEAR IS FORECAST TO BE
HIGHER ON SUNDAY COMPARED TO SATURDAY.
MONDAY AND MONDAY NIGHT...RAIN CHANCES WILL DECREASE SLIGHTLY
ACROSS THE AREA...THOUGH A FEW STORMS WITH HEAVY RAINFALL MAY
CONTINUE TO AGGRAVATE ONGOING FLOODING. CAPPING WILL REMAIN RATHER
WEAK. SHEAR WILL WEAKEN. HOWEVER...THE AIR WILL REMAIN MOIST AND
PERHAPS MORE UNSTABLE COMPARED TO SUNDAY. THINK THERE WILL BE MANY
MORE DRY HOURS ON MONDAY COMPARED TO WET ONES.
TUESDAY THROUGH THURSDAY...A WARM MOIST AIRMASS WILL REMAIN NEARBY
WITH AT LEAST SOME LOW CHANCES FOR STORMS MOST DAYS. INCREASING
MID LEVEL HEIGHTS AND WEAK RIDGING SHOULD DECREASE STORM COVERAGE. ANY
STORM WOULD BE SLOW MOVING AND COULD PRODUCE ADDITIONAL LOCALLY
HEAVY RAINFALL. TEMPERATURES ARE FORECAST TO BE NEAR AVERAGE.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 63 60 76 63 / 90 40 90 90
HOBART OK 65 60 73 61 / 70 50 90 60
WICHITA FALLS TX 69 63 79 64 / 90 30 90 90
GAGE OK 63 57 68 58 / 50 60 90 30
PONCA CITY OK 61 58 70 63 / 90 60 90 80
DURANT OK 69 61 78 65 / 70 20 60 90
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR OKZ004>048-050>052.
TX...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR TXZ083>090.
&&
$$
23/17/17
AREA FORECAST DISCUSSION
NWS PENDLETON OR
835 AM PDT FRI MAY 22 2015
.UPDATE...ABUNDANT MOISTURE CONTINUES TO RAP AROUND A LOW PRESSURE
SYSTEM OVER CALIFORNIA AND INTO OUR AREA. COMBINING THIS WITH
DAYTIME HEATING WILL CONTINUE TO PRODUCE SHOWERS AND THUNDERSTORMS
THIS AFTERNOON. PWAT REMAINS HIGH AND SOME OF THE STORMS MAY BECOME
STRONG AND PRODUCE HEAVY RAIN ESPECIALLY OVER THE EASTERN HALF OF
THE REGION THAT INCLUDES THE BLUE/WALLOWA MTNS ALONG WITH THE JOHN
DAY HIGHLANDS WHERE A FLASH FLOOD WATCH REMAINS IN EFFECT. IN
ADDITION SOME MODIFICATIONS WERE DONE TO AFTN TEMPS AND THE PRESENT
SHORT TERM FORECAST APPEARS ON TRACK FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 300 AM PDT FRI MAY 22 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...A BROAD UPPER LEVEL
TROUGH WILL REMAIN OVER THE REGION THROUGH MUCH OF THIS PERIOD. THE
AIR MASS ACROSS THE REGION WILL REMAIN MOIST AND UNSTABLE TODAY.
INCREASING WEST FLOW FROM THE GORGE SOUTH INTO CENTRAL OREGON WILL
INCREASINGLY LIMIT SHOWER AND THUNDERSTORM CHANCES IN THESE AREAS
LATE THIS AFTERNOON INTO THE EVENING. ELSEWHERE SCATTERED TO
WIDESPREAD SHOWERS WITH ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
POSSIBLE, ESPECIALLY IN THE AFTERNOON AND EVENING. STORM MOTION WILL
BE RELATIVELY SLOW AND DECENT RAINFALL WILL BE POSSIBLE, ESPECIALLY
FROM THUNDERSTORMS. AS THE MAIN SHOWER AND STORM FOCUS LOOKS TO BE
OVER THE EASTERN MOUNTAIN ZONES WILL CONTINUE THE FLASH FLOOD WATCH
COVERING THE OCHOCO-JOHN DAY HIGHLANDS NORTH TO THE BLUE MOUNTAINS
AND NORTHEAST TO WALLOWA COUNTY. A WEAK LOW LOOKS TO SLIDE SOUTH-
SOUTHEAST ACROSS THE REGION TONIGHT. AS A RESULT A DEFORMATION
PRECIP BAND MAY DEVELOP NORTH AND EAST OF THE LOW. AS SUCH WILL KEEP
40-60 PERCENT POPS GOING FROM SOUTH CENTRAL WASHINGTON INTO
NORTHEAST AND EAST CENTRAL OREGON TONIGHT. WESTERLY LOW LEVEL FLOW
WILL CONTINUE TO INCREASE SATURDAY. THUS THE AIR MASS OVER THE
REGION WILL BECOME A BIT DRIER, LIMITING THE AREAS TO BE AFFECTED BY
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. AT THIS
TIME EXPECT SHOWERS/STORMS TO BE MAINLY OVER SOUTH CENTRAL
WASHINGTON AND THE EASTERN MOUNTAIN ZONES. 90
LONG TERM...SUNDAY THROUGH FRIDAY...AN OVERALL DRYING TREND WILL
OCCUR ON SUNDAY WITH NWLY FLOW REGIME BECOMING AT LEAST BRIEFLY
ESTABLISHED OVER THE AREA. THERE WILL STILL BE A SLIGHT CHANCE FOR
AFTERNOON THUNDERSTORMS OVER THE FAR EAST AND ALONG THE WASHINGTON
CASCADE EAST SLOPES. ON MONDAY AN UPPER LOW WILL DROP SWD FROM
BRITISH COLUMBIA INTO WASHINGTON AND BRING A SLIGHT CHANCE FOR
AFTERNOON THUNDERSTORMS EASTERN MOUNTAINS AND WASHINGTON CASCADES.
FROM TUESDAY ONWARD THE MEDIUM RANGE MODELS DIVERGE ON THE HANDLING
OF THE UPPER LOW. THE GFS MEANDERS THE LOW OVER THE FORECAST AREA
KEEPING A CHANCE FOR SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS
EACH DAY THROUGH FRIDAY...WHEREAS THE ECMWF MOVES THE LOW OUT AND
REPLACES IT WITH DRY NW FLOW. FOR NOW HAVE TRENDED THIS FORECAST
UPDATE TOWARD THE GFS WHICH IS IN LINE WITH THE PREVIOUS FORECAST TO
MAINTAIN CONTINUITY. TEMPERATURES WILL BE WARM THROUGH THE PERIOD
WITH HIGHS UPPER 70S TO MID 80S LOWER ELEVATIONS WITH 60S TO LOWER
70S MOUNTAINS.
AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD. SHOWERS/ISOLATED THUNDERSTORMS WILL DEVELOP OVER
THE CENTRAL AND EASTERN MOUNTAINS AND DRIFT WWD AGAIN TODAY STARTING
AROUND 20Z. LIGHTNING MAY BE A BIT LESS THAN ON THURSDAY. FOR NOW
WILL USE VCSH WHICH CAN BE FINE TUNED WITH VCTS IF NECESSARY LATER
THIS MORNING OR EARLY AFTERNOON. CIGS WILL BE 5-8K FEET AGL WITH MID
CLOUD ABOVE. WINDS WILL HAVE A WESTERLY COMPONENT THIS AFTERNOON AT
5-15 KT...EXCEPT 15 TO 25 KT AT KDLS.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 74 54 73 51 / 50 40 40 20
ALW 76 56 75 55 / 50 50 30 20
PSC 83 58 80 54 / 40 40 30 10
YKM 78 59 79 55 / 60 40 40 20
HRI 80 57 78 53 / 50 40 30 10
ELN 79 56 78 54 / 60 40 40 20
RDM 68 44 68 39 / 40 20 20 10
LGD 69 54 68 50 / 80 60 40 30
GCD 68 49 69 45 / 80 60 30 20
DLS 76 57 70 54 / 20 20 20 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FLASH FLOOD WATCH THROUGH THIS EVENING FOR ORZ049-050-502-503-
505-506.
WA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WAZ030.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
97/
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
404 AM MDT FRI MAY 22 2015
.SYNOPSIS...
THE WEEK AHEAD WILL BE MARKED BY WARM SUNNY WEATHER WITH OCCASIONAL
INTRUSIONS OF MOISTURE FROM THE EAST THAT KICK OFF SOME
THUNDERSTORMS. TODAY WILL DRY OUT AND HEAT UP...BUT A SLIGHT RISK OF
A THUNDERSTORM WILL CONTINUE OVER THE SACRAMENTO MOUNTAINS. SUNDAY
SOME MOISTURE WILL RETURN TO HUDSPETH COUNTY FOR A SLIGHT SHOT OF A
THUNDERSTORM. SUNDAY THROUGH TUESDAY BACK TO JUST NORMAL SUNNY AND
WARM WITH TEMPERATURES BACK ABOVE NORMAL. ANOTHER INTRUSION OF
MOISTURE WILL BEGIN ON WEDNESDAY FROM THE RIO GRANDE VALLEY
EAST...WITH ANOTHER CHANCE OF THUNDERSTORMS FOR THIS AREA. THURSDAY
DRYING WILL SPREAD EASTWARD...BUT AREAS EAST OF EL PASO COULD STILL
SEE A THUNDERSTORM.
&&
.DISCUSSION...
WV IMAGERY SHOWS NICE DRYING OUT OF THE ATMOSPHERE WITH DEEP
MOISTURE NOW WELL EAST OF THE AREA...THOUGH DRY SLOT IS FILLING BACK
IN SOMEWHAT WITH SOME HIGH LEVEL MOISTURE. AT THE SURFACE...MOISTURE
(HIGH DEWPOINTS) STILL EXTENDS FROM THE RIO GRANDE VALLEY
EAST...WHERE DEW POINTS REMAIN IN THE UPPER 40S-LOWER 50S. HI RES
MODELS SHOW MOST SURFACE MOISTURE OUT EAST OF THE CWA EXCEPT THE FAR
EAST. HRRR SHOWS MOISTURE STILL FROM ABOUT ALAMOGORDO TO SIERRA
BLANCA AT 18Z...SO LEFT POPS IN FOR THE HIGHER ELEVATIONS (SAC MTNS)
WITHIN THIS AREA. BY AROUND 21Z MOISTURE HAS BEEN PUSHED OUT OF THE
CWA. THIS IS USUALLY ABOUT THE TIME THE LOWLANDS CAN START FIRING
OFF. BREEZY WINDS TO THE WEST OF THE DRYLINE/CONVERGENCE ZONE WILL
DEVELOP THIS AFTERNOON. FIRE WEATHER WATCH LOOKS REASONABLE AT THIS
TIME. WILL LET FIRE WX DESK DECIDE ON UPGRADE TO RED FLAG A BIT
LATER THIS MORNING. DRYLINE/MOISTURE REMAIN MOSTLY EAST OF THE CWA
AGAIN SATURDAY THOUGH NAM12 AND GFS BOTH SHOW MOISTURE UNDULATING
BACK INTO HUDSPETH COUNTY SO KEPT LOW POP IN THERE. BROAD SCALE LIFT
FROM APPROACHING UPPER TROUGH COULD HELP KICK THE STORMS OFF. STORMS
ON EITHER DAY WILL SEE LITTLE IF ANY DIRECTIONAL SHEAR BUT DECENT
SPEED SHEAR COULD PROVIDE SOME BACK BUILDING STORMS.
SUNDAY THROUGH TUESDAY SHOULD BE QUIET WITH DRY WESTERLY FLOW ALOFT.
TEMPS BACK ABOVE NORMAL...WITH THE LOWLANDS SEEING ANOTHER BATCH OF
90 DEGREE DAYS. NEXT UPPER TROUGH APPROACHES THE AREA WEDNESDAY.
THIS WILL ONCE AGAIN DRAW THE DRYLINE BACK INTO OUR AREA. GFS BRINGS
THE DRYLINE AND MOISTURE BACK WEST INTO THE RIO GRANDE VALLEY (ECMWF
KEEPS IT EAST OF EL PASO). FOR NOW LEANED MORE TOWARD THE GFS SINCE
THE DRYLINE HAS BEEN MAKING IT TO THE RIO GRANDE VALLEY...IF NOT
FURTHER WEST. STRONG DIRECTIONAL WIND SHEAR IN THE ATMOSPHERE ALONG
WITH RELATIVELY HIGH CAPES POINT TOWARD A SMALL RISK OF
STRONG/SEVERE THUNDERSTORMS EAST HALF OF THE CWA. RISK OF
THUNDERSTORMS WILL CONTINUE THURSDAY...THOUGH DRYING BEGINS FROM THE
WEST AGAIN. STORMS LIKELY LIMITED TO EAST OF EL PASO.
&&
.AVIATION...VALID 22/12Z-23/12Z...
VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THRU THE PERIOD WITH
P6SM SKC INITIALLY FOLLOWED BY SCT-BKN250 AFTER 18Z. WINDS WILL BE
LIGHT AND FROM THE EAST BEFORE VEERING TO THE SOUTHWEST BY 18Z.
SURFACE WINDS WILL BEGIN TO EXCEED 12 KTS BETWEEN 16Z AND 18Z WITH
GUSTS 20-25 KTS COMMON AT MOST TAF SITES THRU THE AFTERNOON HOURS.
&&
.FIRE WEATHER...
SOUTHWESTERLY FLOW WILL RETURN TO THE AREA FOR THE NEXT FEW DAYS AS
AN UPPER LOW OVER THE SOUTHWESTERN STATES SLOWLY TRACKS TO OUR
NORTH. THIS WILL CREATE RATHER BREEZY AFTERNOONS ACROSS THE REGION
WHILE BRINGING MUCH DRIER AIR BACK TO THE AREA. THE RESULT WILL BE A
DROP IN MIN RH VALUES WITH READINGS IN THE CRITICAL RANGE ACROSS ALL
BUT THE FAR EASTERN ZONES AND SOME OF THE HIGHER TERRAIN BOTH TODAY
AND TOMORROW. RED FLAG CONDITIONS COULD BE MET IN A FEW LOWLAND
SPOTS THE NEXT COUPLE OF AFTERNOONS...ESPECIALLY ACROSS THE
SOUTHWESTERN FIRE ZONES. DRY AND WARM WEATHER WILL PREVAIL THROUGH
THE EARLY PART OF NEXT WEEK BEFORE MOISTURE RETURNS TO THE EASTERN
ZONES ALONG WITH A SLIGHT CHANCE FOR SOME WETTING PRECIP BY
WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 87 61 83 57 84 / 0 0 0 0 0
SIERRA BLANCA 87 61 84 52 81 / 0 0 10 10 0
LAS CRUCES 87 50 81 49 82 / 0 0 0 0 0
ALAMOGORDO 85 53 82 50 82 / 0 0 0 0 0
CLOUDCROFT 62 39 59 37 60 / 10 0 0 0 0
TRUTH OR CONSEQUENCES 82 50 79 48 81 / 0 0 0 0 0
SILVER CITY 77 44 70 41 73 / 0 0 0 0 0
DEMING 85 46 79 46 82 / 0 0 0 0 0
LORDSBURG 84 45 76 45 81 / 0 0 0 0 0
WEST EL PASO METRO 89 61 84 56 83 / 0 0 0 0 0
DELL CITY 84 55 81 50 83 / 0 0 0 0 0
FORT HANCOCK 89 62 86 55 85 / 0 0 0 0 0
LOMA LINDA 82 59 79 51 78 / 0 0 0 0 0
FABENS 88 58 84 54 83 / 0 0 0 0 0
SANTA TERESA 89 56 84 52 84 / 0 0 0 0 0
WHITE SANDS HQ 85 57 81 53 82 / 0 0 0 0 0
JORNADA RANGE 84 48 80 45 82 / 0 0 0 0 0
HATCH 85 49 80 47 83 / 0 0 0 0 0
COLUMBUS 83 52 79 50 82 / 0 0 0 0 0
OROGRANDE 86 57 82 53 82 / 0 0 0 0 0
MAYHILL 70 46 69 42 69 / 10 0 0 0 0
MESCALERO 72 42 70 40 69 / 10 0 0 0 0
TIMBERON 71 44 68 42 69 / 10 0 0 0 0
WINSTON 74 41 71 40 73 / 0 0 0 0 0
HILLSBORO 81 46 80 44 80 / 0 0 0 0 0
SPACEPORT 84 45 80 45 82 / 0 0 0 0 0
LAKE ROBERTS 76 40 70 39 73 / 0 0 0 0 0
HURLEY 78 43 73 41 76 / 0 0 0 0 0
CLIFF 81 40 75 40 79 / 0 0 0 0 0
MULE CREEK 78 38 75 36 77 / 0 0 0 0 0
FAYWOOD 78 45 75 43 77 / 0 0 0 0 0
ANIMAS 82 45 78 46 82 / 0 0 0 0 0
HACHITA 86 44 80 45 83 / 0 0 0 0 0
ANTELOPE WELLS 85 43 81 45 82 / 0 0 0 0 0
CLOVERDALE 78 44 77 43 78 / 0 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...FIRE WEATHER WATCH FROM 2 PM MDT THIS AFTERNOON THROUGH THIS
EVENING FOR NMZ111.
TX...NONE.
&&
$$
HEFNER/LANEY
AREA FORECAST DISCUSSION
NWS SEATTLE WA
515 AM PDT FRI MAY 22 2015
.UPDATE...SHOWERS HAVE BEEN INCREASING THE LAST COUPLE OF HOURS AND
AND DRIFTING WEST FROM THE CASCADES INTO THE LOWLANDS FROM ABOUT
EVERETT SOUTHWARD. THE HRRR MODEL SEEMS TO HAVE THE BEST HANDLE ON
THIS ACTIVITY AND SUGGESTS THERE WILL BE ISOLATED SHOWERS THIS
MORNING OVER CENTRAL AND SOUTH PUGET SOUND AND THE SOUTHWEST
INTERIOR BEFORE THEY MOSTLY PETER OUT AND BECOME CONFINED TO THE
MOUNTAINS IN THE AFTERNOON. THE FORECAST WAS UPDATED TO ACCOUNT FOR
THESE CHANGES. THE REMAINDER OF THE FORECAST REMAINS ON TRACK AND
WAS NOT CHANGED. SCHNEIDER
&&
.SYNOPSIS...SKIES WILL BE MOSTLY CLOUDY TODAY AND SATURDAY WITH
MODERATE TO STRONG ONSHORE FLOW. ONSHORE FLOW WILL CONTINUE NEXT
WEEK FOR A PATTERN OF MORNING CLOUDS AND PARTIAL AFTERNOON SUNSHINE
EACH DAY. WEAK LOW PRESSURE ALOFT WILL BRING A CHANCE OF SHOWERS...
MAINLY OVER THE MOUNTAINS AFTERNOON AND EVENINGS.
&&
.SHORT TERM...LOW LEVEL ONSHORE FLOW WILL BE STRONGER TODAY COMPARED
TO YESTERDAY. LOW CLOUDS HAVE BEEN SPREADING INTO THE INTERIOR EARLY
THIS MORNING AND SHOULD COVER MOST OF THE LOWLANDS IN A FEW HOURS.
THERE WILL PROBABLY NOT BE MUCH CLEARING TODAY EVEN IN THE AFTERNOON
ALTHOUGH THERE COULD BE A FEW SUN BREAKS. HIGHS WILL COOL INTO THE
60S. THERE WILL BE A CHANCE OF MAINLY MOUNTAIN SHOWER AND
THUNDERSTORMS IN THE AFTERNOON WHERE THE AIR MASS IS MOST UNSTABLE.
SATURDAY AND SUNDAY LOOK LIKE RELATIVE REPEATS OF TODAY WITH
MODERATE TO STRONG LOW LEVEL ONSHORE FLOW CONTINUING AND SOMEWHAT
UNSTABLE AIR OVER THE MOUNTAINS FOR A CHANCE OF AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS. SCHNEIDER
.LONG TERM...THE GENERAL PATTERN WILL CHANGE VERY LITTLE MONDAY
THROUGH THURSDAY. A WEAK UPPER TROUGH WILL BE OVER THE PACIFIC
NORTHWEST WITH LOW LEVEL ONSHORE FLOW. THERE SHOULD BE MORNING
CLOUDS AND SOME AFTERNOON SUNSHINE EACH DAY WITH A CHANCE OF
SHOWERS... MAINLY OVER THE MOUNTAINS AFTERNOON AND EVENING HOURS.
HIGHS WILL BE NEAR OR SLIGHTLY ABOVE NORMAL. SCHNEIDER
&&
.AVIATION...AN UPPER LOW OVER THE CENTRAL COAST OF BRITISH COLUMBIA
WILL REMAIN STATIONARY THROUGH TODAY KEEPING THE FLOW ALOFT LIGHT.
LOW LEVEL ONSHORE FLOW CONTINUING TODAY. AIR MASS DESTABILIZING OVER
THE CASCADES THIS AFTERNOON.
SATELLITE IMAGERY SHOWS STRATUS ALONG THE COAST...DOWN THE STRAIT
INTO THE SAN JUANS AND EXTENDING INLAND TO THE CENTRAL PUGET SOUND
AT 10Z. CEILINGS ARE BELOW 1000 FEET WITH THE STRATUS. EXPECT ALL OF
THE INTERIOR LOWLANDS EXCEPT THE CASCADE FOOTHILLS TO BE COVERED IN
STRATUS BY 14Z. ONSHORE FLOW CONTINUING TODAY KEEPING THE STRATUS
INTACT OVER THE LOWLANDS WELL INTO THE AFTERNOON. CEILINGS WILL
SLOWLY LIFT INTO THE 1000-2000 FOOT RANGE BY LATE MORNING AND TO
NEAR 3000 FEET BY LATE AFTERNOON OVER THE INTERIOR. CEILINGS ALONG
THE COAST WILL STAY IN THE 1000-2000 FOOT RANGE. THE BEST CHANCES
FOR SOME CLEARING WILL BE NEAR KBLI. WITH THE ONSHORE FLOW PATTERN
CONTINUING INTO SATURDAY MORNING STRATUS WILL REMAIN OVER THE
INTERIOR WITH CEILINGS LOWERING BACK DOWN INTO THE 1000-2000 FOOT
RANGE TONIGHT. THERE IS A CHANCE OF MORE THUNDERSTORM ACTIVITY AGAIN
OVER THE CASCADES TONIGHT WITH MOST OF THE ACTIVITY EXPECTED TO STAY
NEAR THE CREST.
KSEA...CEILINGS BELOW 1000 FEET UNTIL LATE MORNING LIFTING TO NEAR
3000 FEET BY LATE AFTERNOON. SOUTHERLY WINDS 6 TO 10 KNOTS. FELTON
&&
.MARINE...PERSISTENT HIGH PRES OFFSHORE WITH LOWER PRES INLAND WILL
RESULT IN CONTINUED ONSHORE FLOW OF VARYING STRENGTH THROUGH TUE.
ANOTHER ROUND OF GALE FORCE WINDS ARE EXPECTED IN THE CENTRAL AND
EASTERN STRAIT TONIGHT. EXPECT SMALL CRAFT ADVISORY WINDS LATE IN
THE DAY SATURDAY THROUGH THE FIRST PART OF NEXT WEEK FOR THE CENTRAL
AND EASTERN STRAIT WITH THE LOW LEVEL ONSHORE FLOW CONTINUING. SMALL
CRAFT ADVISORY WINDS ARE ALSO FORECAST FOR THE OUTER COASTAL WATERS
TODAY. WITH THE GRADIENT WEAKENING SLIGHTLY LATER TODAY THE WINDS IN
THE OUTER WATERS WILL FALL BELOW 20 KNOTS. WINDS OVER THE REMAINDER
OF THE WATERS WILL REMAIN BELOW 20 KNOTS THE NEXT FEW DAYS. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING CENTRAL AND EAST ENTRANCE STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
&&
$$
AREA FORECAST DISCUSSION
NWS SEATTLE WA
320 AM PDT FRI MAY 22 2015
.SYNOPSIS...SKIES WILL BE MOSTLY CLOUDY TODAY AND SATURDAY WITH
MODERATE TO STRONG ONSHORE FLOW. ONSHORE FLOW WILL CONTINUE NEXT
WEEK FOR A PATTERN OF MORNING CLOUDS AND PARTIAL AFTERNOON SUNSHINE
EACH DAY. WEAK LOW PRESSURE ALOFT WILL BRING A CHANCE OF SHOWERS...
MAINLY OVER THE MOUNTAINS AFTERNOON AND EVENINGS.
&&
.SHORT TERM...LOW LEVEL ONSHORE FLOW WILL BE STRONGER TODAY COMPARED
TO YESTERDAY. LOW CLOUDS HAVE BEEN SPREADING INTO THE INTERIOR EARLY
THIS MORNING AND SHOULD COVER MOST OF THE LOWLANDS IN A FEW HOURS.
THERE WILL PROBABLY NOT BE MUCH CLEARING TODAY EVEN IN THE AFTERNOON
ALTHOUGH THERE COULD BE A FEW SUN BREAKS. HIGHS WILL COOL INTO THE
60S. THERE WILL BE A CHANCE OF MAINLY MOUNTAIN SHOWER AND
THUNDERSTORMS IN THE AFTERNOON WHERE THE AIR MASS IS MOST UNSTABLE.
SATURDAY AND SUNDAY LOOK LIKE RELATIVE REPEATS OF TODAY WITH
MODERATE TO STRONG LOW LEVEL ONSHORE FLOW CONTINUING AND SOMEWHAT
UNSTABLE AIR OVER THE MOUNTAINS FOR A CHANCE OF AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS. SCHNEIDER
.LONG TERM...THE GENERAL PATTERN WILL CHANGE VERY LITTLE MONDAY
THROUGH THURSDAY. A WEAK UPPER TROUGH WILL BE OVER THE PACIFIC
NORTHWEST WITH LOW LEVEL ONSHORE FLOW. THERE SHOULD BE MORNING
CLOUDS AND SOME AFTERNOON SUNSHINE EACH DAY WITH A CHANCE OF
SHOWERS... MAINLY OVER THE MOUNTAINS AFTERNOON AND EVENING HOURS.
HIGHS WILL BE NEAR OR SLIGHTLY ABOVE NORMAL. SCHNEIDER
&&
.AVIATION...AN UPPER LOW OVER THE CENTRAL COAST OF BRITISH COLUMBIA
WILL REMAIN STATIONARY THROUGH TODAY KEEPING THE FLOW ALOFT LIGHT.
LOW LEVEL ONSHORE FLOW CONTINUING TODAY. AIR MASS DESTABILIZING OVER
THE CASCADES THIS AFTERNOON.
SATELLITE IMAGERY SHOWS STRATUS ALONG THE COAST...DOWN THE STRAIT
INTO THE SAN JUANS AND EXTENDING INLAND TO THE CENTRAL PUGET SOUND
AT 10Z. CEILINGS ARE BELOW 1000 FEET WITH THE STRATUS. EXPECT ALL OF
THE INTERIOR LOWLANDS EXCEPT THE CASCADE FOOTHILLS TO BE COVERED IN
STRATUS BY 14Z. ONSHORE FLOW CONTINUING TODAY KEEPING THE STRATUS
INTACT OVER THE LOWLANDS WELL INTO THE AFTERNOON. CEILINGS WILL
SLOWLY LIFT INTO THE 1000-2000 FOOT RANGE BY LATE MORNING AND TO
NEAR 3000 FEET BY LATE AFTERNOON OVER THE INTERIOR. CEILINGS ALONG
THE COAST WILL STAY IN THE 1000-2000 FOOT RANGE. THE BEST CHANCES
FOR SOME CLEARING WILL BE NEAR KBLI. WITH THE ONSHORE FLOW PATTERN
CONTINUING INTO SATURDAY MORNING STRATUS WILL REMAIN OVER THE
INTERIOR WITH CEILINGS LOWERING BACK DOWN INTO THE 1000-2000 FOOT
RANGE TONIGHT. THERE IS A CHANCE OF MORE THUNDERSTORM ACTIVITY AGAIN
OVER THE CASCADES TONIGHT WITH MOST OF THE ACTIVITY EXPECTED TO STAY
NEAR THE CREST.
KSEA...CEILINGS BELOW 1000 FEET UNTIL LATE MORNING LIFTING TO NEAR
3000 FEET BY LATE AFTERNOON. SOUTHERLY WINDS 6 TO 10 KNOTS. FELTON
&&
.MARINE...PERSISTENT HIGH PRES OFFSHORE WITH LOWER PRES INLAND WILL
RESULT IN CONTINUED ONSHORE FLOW OF VARYING STRENGTH THROUGH TUE.
ANOTHER ROUND OF GALE FORCE WINDS ARE EXPECTED IN THE CENTRAL AND
EASTERN STRAIT TONIGHT. EXPECT SMALL CRAFT ADVISORY WINDS LATE IN
THE DAY SATURDAY THROUGH THE FIRST PART OF NEXT WEEK FOR THE CENTRAL
AND EASTERN STRAIT WITH THE LOW LEVEL ONSHORE FLOW CONTINUING. SMALL
CRAFT ADVISORY WINDS ARE ALSO FORECAST FOR THE OUTER COASTAL WATERS
TODAY. WITH THE GRADIENT WEAKENING SLIGHTLY LATER TODAY THE WINDS IN
THE OUTER WATERS WILL FALL BELOW 20 KNOTS. WINDS OVER THE REMAINDER
OF THE WATERS WILL REMAIN BELOW 20 KNOTS THE NEXT FEW DAYS. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING CENTRAL AND EAST ENTRANCE STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
259 AM PDT FRI MAY 22 2015
.SYNOPSIS...
The Memorial Day Weekend is expected to be warmer than average
with afternoon temperatures in the 70s and 80s. Look for scattered
showers and thunderstorms this weekend into next week. Some
thunderstorms will be capable of producing heavy downpours and
frequent lightning.
&&
.DISCUSSION...
Today through Saturday night: The weather pattern will see subtle
changes as we move into the holiday weekend, keeping a persistence
forecast with minor adjustments. The upper level pattern remain
diffuse and in chaos with broad trough across the western U.S.
Shortwaves embedded in the trough will provide the lift for
convection. While the main circulation lies over southern CA and
helps pump moisture up across the Rockies into the Pac NW, a
second circulation will be dropping down the BC coast. Even though
somewhat drier northeast flow resides over northeast Washington
and far northern Panhandle, pwats continue to be high, near an
inch, across the Cascades and southern Washington, similar to
yesterday, which will help fuel convection. In fact, yesterday`s
convection developed over southeast Washington and Blue mountains
and took a slow track westward toward the Cascades without any
real kicker. Anticipate similar conditions today, but possibly a
better chance of convection as the northern shortwave approaches.
As this feature arrives in northwest Washington this afternoon, it
will weaken but may provide enough lift to enhance convection in
the Cascades. Wet bulb zero heights will be approaching 10k while
cape values near 1000 j/kg in the Cascades, and even higher in the
Blue mountains by this afternoon. The instability values alone
would lean toward stronger thunderstorms will larger hail, but the
warmer atmosphere may lead to more heavy rain. Given the slow
steer flow and weak shear, would side with heavy rain and possible
flooding as the main impacts. Agree with the current flash
flooding watch for the northern Cascades given the many burn scars
for recent fires and any thunderstorm that sits over a burn area
too long may lead to issues. The Blue mountains area will most
likely see the stronger storms with both heavy rain and hail.
Anticipate the thunder threat to decrease by early evening and the
convection to wane overnight. By Saturday, the drier and more
stable over northeast Washington filters into the region as the
remnants of the shortwave side into Oregon. The bulk of mid/upper
level moisture sinks south of the region. May still see afternoon
convection, but current model runs paint less instability and
moisture over the Inland Northwest, although the areas of concern
will still be near the Cascade crest and the Blue mountains and
the southern ID panhandle. Temperatures were bumped on Saturday
following a more persistence forecast, although not as warm as
experienced yesterday. Expect the diurnally convection to decrease
by Saturday evening with light winds both at the surface and
aloft. /rfox
Sunday and Memorial Day: We should see a subtle change in the
pattern Sunday into Monday which has the potential to shift our
best chances for showers from our southern Panhandle and Cascade
zones to our northeast Washington and north Idaho zones. The
upper low which has been over southern California for the last
week is expected to migrate into the Central Rockies Sunday night
into Monday. A weak, slow moving trough is expected to descend
from British Columbia into western or central Washington Sunday
into Monday. This change in the upper pattern will bring a shift
in our storm steering flow from our current light easterly flow to
our more typical westerly flow by Sunday afternoon. Surface
dewpoints in northeast Washington and far north Idaho should
increase Sunday and Monday yielding higher surface based
instability in places like Colville, Republic, Sandpoint, and
Bonners Ferry. If the GFS, ECMWF and Canadian GEM hold true, our
best chance for showers and thunderstorms on Sunday afternoon will
be over the north Cascades into the Okanogan Highlands. For Monday
afternoon, the focus will shift into the Idaho Panhandle and
northeast Washington. The increased onshore flow Monday should
push high temperature down a few degrees and the increased west to
east pressure gradient should produce more wind (10-15mph out of
the west or southwest).
Tuesday through Thursday: Chances for showers Tuesday through
Thursday will largely vary on what happens to the upper low that
descends from B.C. on Monday. The GFS and Canadian models are very
slow to move this feature suggesting good chances for showers and
thunderstorms Tuesday, Wednesday, and Thursday. The ECMWF moves
the upper low out more quickly with less convection Wednesday and
Thursday. Our forecast was based on a troughy GFS ensemble mean.
/GKoch
&&
.AVIATION...
06Z TAFS: Scattered showers is expected for the remainder of
tonight mainly in the Cascades and across Central and southern
section of Eastern Washington and the Lewiston area as moisture
continues to be pulled into the area. A couple stray lightning
strikes will also be possible but should not impact any of the TAF
sites. Afternoon convection will again develop on Friday over
similar areas as today. The HRRR shows convection will begin to
fire over the high terrain of the Cascades and Blue Mountains
around 18z Fri. Gusty outflow winds and brief heavy rain will be
the main threats from Thunderstorms on Friday. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 82 53 80 53 79 53 / 10 10 10 10 20 30
Coeur d`Alene 81 52 79 53 79 52 / 10 10 10 10 20 30
Pullman 75 49 73 47 75 49 / 30 40 20 10 10 10
Lewiston 80 56 79 54 82 56 / 40 40 20 20 20 20
Colville 86 53 83 55 82 52 / 10 10 10 10 30 30
Sandpoint 81 50 80 48 77 50 / 10 0 10 10 20 20
Kellogg 80 50 79 49 78 50 / 20 10 30 20 20 20
Moses Lake 86 56 84 55 83 54 / 20 10 10 10 20 20
Wenatchee 84 59 83 58 82 57 / 50 30 20 10 20 20
Omak 86 53 85 54 83 53 / 20 20 10 10 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch from 1 PM PDT this afternoon through this
evening for East Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1205 PM CDT FRI MAY 22 2015
.UPDATE...
ISSUED AT 940 AM CDT FRI MAY 22 2015
TEMPERATURES ARE RECOVERING QUICKLY WITH ABUNDANT SUNSHINE...BUT
CIRRUS CLOUDS ARE STARTING TO CREEP INTO THE FAR WESTERN CWA.
HAVE MADE SOME TWEAKS TO THE HIGH TEMPERATURES...GOING WITH MID
70S EVERYWHERE. WILL NEED TO WATCH THIS DURING THE AFTERNOON...AS
THE HRRR IS HINTING AT UPPER 70S OVER THE SOUTHWEST. HOWEVER...THE
HIGH CLOUDS WILL BE THICKENING UP DURING THE AFTERNOON...SO THIS
MAY HELP KEEP TEMPERATURES IN CHECK.
&&
.SHORT TERM...(TODAY)
ISSUED AT 331 AM CDT FRI MAY 22 2015
A BEAUTIFUL SPRING DAY EXPECTED TODAY ACROSS IL WITH A FAIR AMOUNT
OF SUNSHINE AND FAIRLY LIGHT WINDS AND MILD HIGHS IN THE MID 70S. A
WEAK FRONTAL BOUNDARY NEAR I-88 IN NORTHERN IL EARLY THIS MORNING
WILL DROP SOUTHWARD ACROSS CENTRAL IL DURING THIS MORNING AND
THROUGH SOUTHEAST IL DURING THE AFTERNOON. LITTLE IF ANY LIFT OR
MOISTURE TO WORK WITH SO EXPECT THIS FRONT TO SHIFT BE ACCOMPANIED
BY A WEAK WIND SHIFT FROM THE SW TO THE NW. CIRRUS CLOUDS TO
INCREASE FROM THE WEST LATER THIS MORNING AND AFTERNOON AS SUNNY
SKIES THIS MORNING BECOME PARTLY TO MOSTLY SUNNY IN THE AFTERNOON.
NUDGED HIGHS UP SLIGHTLY TODAY INTO THE MID 70S ACROSS MUCH OF THE
AREA WITH AREAS FROM I-74 NE SLIGHTLY COOLER.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 331 AM CDT FRI MAY 22 2015
NICE WEATHER TO CONTINUE ACROSS IL DURING THE FIRST HALF OF THE
MEMORIAL DAY WEEKEND AS DRY CONDITIONS PERSIST THROUGH SATURDAY.
HIGH PRESSURE DRIFTS SE FROM LAKE SUPERIOR INTO THE MID ATLANTIC
STATES SATURDAY WHILE UPPER LEVEL RIDGE NOSES INTO THE MS RIVER
VALLEY. THIS TO MAINTAIN DRY CONDITIONS TONIGHT AND SATURDAY ACROSS
CENTRAL AND SOUTHEAST IL. MID AND HIGH CLOUDS CONTINUE TO INCREASE
TONIGHT AND SATURDAY WITH SKIES TRENDING TOWARD PARTLY TO MOSTLY
CLOUDY. LOWS TONIGHT IN THE LOW TO MID 50S WITH HIGHS SAT IN THE MID
TO UPPER 70S.
LARGE UPPER LEVEL TROF/LOW DIGGING OVER THE ROCKIES DURING THIS
WEEKEND TO EJECT SHORT WAVES NE INTO THE CENTRAL PLAINS SAT NIGHT
AND INTO THE UPPER MS RIVER VALLEY ON SUNDAY. SURFACE LOW PRESSURE
EMERGES OVER THE CENTRAL PLAINS SUNDAY AND LIFTS UP INTO THE UPPER
MS RIVER VALLEY AND NORTHERN PLAINS MONDAY. A WARM FRONT TO LIFT
NORTHWARD ACROSS CENTRAL IL SUNDAY MORNING. THIS TO BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO WESTERN AREAS OVERNIGHT SAT NIGHT
AND THEN LIKELY CHANCES WEST OF I-57 SUNDAY AND SUNDAY NIGHT AND 40-
50% CHANCE OVER EASTERN IL SUNDAY FROM I-57 EAST. MORE HUMID ON
SUNDAY AS WARM FRONT LIFTS NORTH WITH SOUTHERLY FLOW DEVELOPING AS
DEWPOINTS ELEVATE INTO THE MID 60S BY SUNDAY AFTERNOON WITH HIGHS IN
THE UPPER 70S CENTRAL IL AND NEAR 80F IN SOUTHEAST IL. SPC KEEPS
MARGINAL RISK OF SEVERE STORMS SW OF CENTRAL IL SUNDAY AFTERNOON AND
EVENING WHERE BETTER INSTABILITY WILL BE DURING PEAK HEATING.
EXTENDED MODELS CONTINUE AN UNSETTLED WEATHER PATTERN THROUGH MUCH
OF NEXT WORK WEEK WITH DAILY CHANCES OF SHOWERS AND THUNDERSTORMS AS
FRONTAL BOUNDARY STAYS NW OF IL THROUGH AT LEAST WED AND POSSIBLY
LONGER. CONTINUE LIKELY CHANCES OF SHOWERS AND THUNDERSTORMS MONDAY
WITH HIGHS AROUND 80F AND DEWPOINTS IN THE MID TO UPPER 60S. BREEZY
CONDITIONS EXPECTED MONDAY SIMILAR TO SUNDAY IN THE WARM SECTOR.
CONTINUED GOOD CHANCE OF SHOWERS AND THUNDERSTORMS DURING MIDDLE OF
NEXT WEEK AND WARM HIGHS IN THE LOWER 80S AND LOWS IN THE MID TO
UPPER 60S. CPC 8-14 DAY OUTLOOK FROM MAY 29 THRU JUNE 4 CONTINUES 40-
50% CHANCE OF ABOVE NORMAL TEMPERATURES AND PRECIPITATION. SO A
WARM AND WET PATTERN LOOKS TO CONTINUE INTO THE FIRST WEEK OF
JUNE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1205 PM CDT FRI MAY 22 2015
VFR CONDITIONS ON TAP THROUGH THE PERIOD. HIGH CLOUDS WILL SPREAD
IN THIS AFTERNOON AND GRADUALLY LOWER TO AROUND 10KFT THIS
EVENING...WHICH WILL PERSIST THE REMAINDER OF THE PERIOD. WINDS
WILL BECOME LIGHT/VARIABLE TONIGHT...BEFORE A SOUTHERLY WIND PICKS
UP LATE SATURDAY MORNING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...07
LONG TERM...07
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
317 PM EDT FRI MAY 22 2015
.SYNOPSIS...
ISSUED AT 630 AM EDT FRI MAY 22 2015
CLEAR SKIES AND DRY WEATHER WILL PREVAIL TONIGHT AND SATURDAY.
TEMPERATURES WILL DROP INTO THE UPPER 30S TO LOWER 40S
TONIGHT...AND AFTER A CHILLY START SATURDAY MORNING...HIGHS WILL
REACH THE LOWER 70S WITH ABUNDANT SUNSHINE AND LIGHT WINDS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 313 PM EDT FRI MAY 22 2015
CLEAR AND DRY WEATHER FOR TONIGHT AND SATURDAY. BOUNDARY LAYER TROF
SWEPT SOUTH ACROSS THE AREA THIS MORNIGN AND DEWPOINTS DROPPED 15 TO
18 DEGREES. THIS IS NOTED ON SURFACE ANAYLSIS WITH DEWPOINTS IN THE
50S ALONG THE SOUTHERN CWA BORDER...WHILE DEWPOINTS ACROSS THE NORTH
ARE IN THE LOWER 30S. WINDS LIGHT AND VARIABLE...WITH A SLIGT
EASTERLY COMPONENT WILL CONTINUE TO USHER IN THE COOLER/DRIER AIR
OVERNIGHT. PATCHY FROST IS NOT OUT OF THE QUESTION...ESPECIALLY
ACROSS THE EXTREME NORTHERN TIER COUNTIES. HRRR AND WRF BOTH SUGGEST
THAT BOUDNARY LAYER MOISTURE WILL INCREASE BY SUNRISE SATURDAY...SO
HAVE OPTED TO KEEP PATCHY FROST OUT OF THE GRIDS FOR THE AFTERNOON
UPDATE.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 313 PM EDT FRI MAY 22 2015
MODELS CONTINUE TO WEAKEN AND SLOW APPROACHING SYSTEM FOR LATE
WEEKEND INTO NEXT WEEK. UPPER LOW HAS MOVED ONSHORE OVER SOUTHERN CA
AND WILL DRIFT THROUGH THE ROCKIES THIS WEEKEND AND INTO THE
NORTHERN PLAINS EARLY NEXT WEEK. MEANWHILE...BERMUDA HIGH OVER
ATLANTIC WILL STRENGTHEN AND BUILD TOWARD SOUTHEAST COAST. RESULT
WILL BE RISING HEIGHTS OVER MIDWEST WITH BUILDING SHORT WAVE RIDGE.
THIS WILL LEAD TO A WARMER AND MORE MOIST ENVIRONMENT BY LATE WEEKEND
AND THROUGH MUCH OF NEXT WEEK. NO STRONG SIGNAL FOR WIDESPREAD PCPN
DEVELOPMENT BUT ANY SUBTLE SYNOPTIC SCALE SHORT WAVES OR
CONVECTIVELY INDUCED WAVE COULD EASILY GENERATE ROUNDS OF CONVECTION
FOR MUCH OF THE PERIOD BEGINNING SUNDAY GIVEN HIGH PWATS AND
MOISTURE TRANSPORT. SMALL SCALE DETAILS REMAIN DIFFICULT TO NAIL DOWN
WITH QUITE A BIT OF MODEL UNCERTAINTY AND DISAGREEMENT THROUGH THE
PERIOD. GENERAL ENSEMBLE BLEND APPROACH USED FOR POPS AND TEMPS
THROUGH THE LONG TERM PERIOD WITH SUPERBLEND PREFERRED. DID LOWER
SUPERBLEND POPS SEVERAL PERIODS WITH THE UNCERTAINTY BUT LEFT LOW
END LIKELY POPS FOR MONDAY IN THE WEST. STAYED MIDDLE OF THE ROAD
WITH TEMPS GIVEN POSSIBILITY OF COOLER WITH CLOUDS AND RAIN OR
WARMER WITH LACK OF PCPN AND POTENTIAL MIXING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 313 PM EDT FRI MAY 22 2015
VFR CONDITIONS CONTINUE THROUGH THE FORECAST PERIOD. LIGHT AND
VARIABLE WINDS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LEWIS
SHORT TERM...LEWIS
LONG TERM...LASHLEY
AVIATION...LEWIS
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
248 PM MDT FRI MAY 22 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY AFTERNOON)
ISSUED AT 247 PM MDT FRI MAY 22 2015
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS CLOSED LOW OVER
THE SW US...WITH A NEGATIVELY TILTED TROUGH CENTERED OVER THE
NEBRASKA PANHANDLE/NORTHEAST COLORADO. SATELLITE SHOWS CLEARING
BEGINS TO MOVE INTO THE SW PART OF THE CWA...WITH STRATUS/SHOWERS
TRANSITIONING NORTHWARDS. THUNDERSTORMS ARE ALREADY BEGINNING TO
FIRE ALONG PALMER DIVING ALONG NORTHERN EXTENT OF SURFACE LOW IN
EASTERN COLORADO.
REGARDING SEVERE THREAT THIS AFTERNOON THROUGH TONIGHT...WITH
CLEARING TAKING PLACE IN THE SW RAP AND OBJECTIVE ANALYSIS INDICATED
500-1500 J/KG OF SB CAPE ALREADY DEVELOPING...AND GUIDANCE WOULD
FAVOR THIS DEVELOPING INTO THE SW PART OF THE CWA (ASSOCIATED WITH
CLEARING. GOOD VEERING PROFILES ARE IN PLACE ALONG AND JUST NORTH OF
THE SURFACE LOW WHERE RAP IS HINTING AT HELICITY VALUES APPROACHING
250 M2/S2 BY 00Z. ORGANIZED SUPERCELL/TORNADO THREAT SEEMS TO BE
TIED TO THIS SURFACE LOW AND WOULD FAVOR THE SOUTHWEST PART OF OUR
CWA. DEEP SPEED SHEER CONTINUES OVERNIGHT AND GUIDANCE INDICATES
AROUND 1000 J/KG OF MU CAPE (POSSIBLY HIGHER IF NAM IS TO BE
TRUSTED). STRONG ISENTROPIC SIGNAL CONTINUES THROUGH THE NIGHTTIME
PERIOD...AND SEVERAL LOBES OF VORTICITY AND OMEGA ROTATE THROUGH
THE REGION. THIS SHOULD COMBINE TO CREATE
SHOWERS/THUNDERSTORMS...POSSIBLY A SEVERE HAIL THREAT IF WE SEE ANY
THUNDERSTORMS. NOT AS SURE ABOUT WIND THREAT CONSIDERING THE
PROFILES AND STABLE LOWER LEVELS.
FOG/STRATUS/DRIZZLE WILL BE POSSIBLE ALL NIGHT WITH GOOD BL MOISTURE
FLUX THROUGH SATURDAY MORNING...TRANSITIONING EASTWARD. WITH BETTER
SHOWER/THUNDERSTORM/DRIZZLE COVERAGE DENSE FOG MAY NOT BE AS MUCH OF
A CONCERN DUE TO THE INCREASE IN MIXING. WILL NEED TO MONITOR AS
LESS MIXING WOULD RESULT IN DENSE FOG DUE TO THE LONG FETCH
UPSLOPE/MAGNITUDE OF MOISTURE ADVECTION.
GUIDANCES SHOWS TWO DISTINCT SHORTWAVE TROUGHS SATURDAY
MORNING...ONE IN THE SOUTHERN PLAINS AND ANOTHER DEVELOPING INTO
NORTHERN COLORADO BY LATE AFTERNOON AS THE H3 JET BEGINS TO SHIFT
EASTWARD. THERE SEEMS TO BE A LULL IN ACTIVITY BETWEEN THESE
FEATURES LIKELY DUE TO SOME WEAK SUBSIDENCE...AND NAM IS REALLY
HITTING THIS DRY PERIOD HARDER COMPARED TO GFS/ECMWF. DECIDED OT
TIMING OUT THE LULL TO FAVOR LOWER POPS SAT MORNING...BEFORE
COVERAGE REDEVELOPS IN THE AFTERNOON. BETTER PRECIP SIGNAL IS AGAIN
IN EASTERN COLORADO BY MID AFTERNOON. CAPE PROFILES ARE MUCH MORE
ROBUST ACROSS THE MAJORITY OF THE CWA...AS WELL AS GOOD SHEER. AS A
RESULT WE WILL PROBABLY SEE A BETTER SEVERE THREAT SATURDAY
AFTERNOON THAN TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 247 PM MDT FRI MAY 22 2015
THE SLOW-MOVING UPPER LOW OVER UT/CO AT THE BEGINNING OF THE PERIOD
IS FORECAST TO LIFT NORTHEAST INTO THE DAKOTAS BY EARLY NEXT
WEEK...BUT NOT BEFORE SWINGING SEVERAL MORE SHORT WAVE TROUGHS
AROUND ITS PERIPHERY ACROSS THE FORECAST AREA. THE PATTERN WILL
BE SOMEWHAT LESS ACTIVE FOR THE MIDDLE OF THE WEEK WITH
THUNDERSTORM POTENTIAL A BIT MORE OF THE HIT-AND-MISS VARIETY
BEFORE ANOTHER TROUGH DEVELOPS IN THE WEST TOWARD THE END OF THE
WEEK. OVERALL...THE LONG RANGE PERIOD WILL BE ONE OF DECREASING
PRECIPITATION POTENTIAL WITH TEMPERATURES WARMING BACK TO SEASONAL
NORMS IN THE 70S/LOW 80S FOR HIGHS AND 50S FOR LOWS.
TO START THE EXTENDED PERIOD...THERE IS DECENT POTENTIAL FOR
STRONG TO SEVERE STORMS SATURDAY AFTERNOON-EVENING AS THE UPPER
LOW MOVES INTO WESTERN COLORADO AND A SURFACE DRYLINE SETS UP OVER
EC/SE COLORADO. A 100 KT 250 MB JET STREAK WILL BE RUNNING UP THE
EAST SIDE OF THE UPPER LOW ALONG THE C0-KS BORDER DURING PEAK
HEATING...AND WITH LOW LEVEL MOISTURE ALREADY IN PLACE...A ROUND
OF SEVERE STORMS SEEMS PROBABLE IN EASTERN COLORADO AND WESTERN
KANSAS. STORMS WILL MOVE QUICKLY NORTH INTO NEBRASKA DURING THE
EVENING.
SUNDAY AFTERNOON/NIGHT...THE TAIL END OF THE UPPER LOW/TROUGH
WILL FINALLY SWING THROUGH THE AREA SO CONTINUED CHANCE POPS AS A
RESULT. WEAK SUBSIDENCE BEHIND THIS FEATURE ON MONDAY WILL PROVIDE
A LITTLE RELIEF FROM THE ONSLAUGHT OF RECENT PRECIPITATION.
MID WEEK WILL BE CHARACTERIZED BY A QUASI ZONAL FLOW WITH A FEW
WEAK EMBEDDED TROUGH WHICH WILL KEEP SLIGHT CHANCE TO CHANCE POPS
FOR THUNDERSTORMS BUT OTHERWISE ACCOMPANIED BY TEMPERATURES MORE
TYPICAL OF LATE MAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1130 AM MDT FRI MAY 22 2015
VERY MOIST AIR MASS AND LARGE SCALE SYSTEM TO THE WEST WILL RESULT
IN SHOWERS...THUNDERSTORMS...FOG...AND LOW STRATUS POTENTIAL AT
BOTH TAF SITES. CONFIDENCE HAS DECREASED IN LIFR FOG DUE TO
POTENTIAL FOR PATTERN TO FAVOR STRATUS/PRECIP AND THIS COULD KEEP
VIS IN THE 1-3SM RANGE (FAVORED BY CURRENT STATISTICAL GUIDANCE).
I COULD SEE TEMPORARY DROPS BELOW ONE MILE IN THE 08-13Z
TIMEFRAME...HOWEVER CONFIDENCE IS JUST TOO LOW TO PREVAIL. IN IN
CASE PERIODS OF IFR/LIFR CONDITIONS WILL BE POSSIBLE...WITH SLIGHT
IMPROVEMENTS TO MVFR THIS AFTERNOON AND AGAIN SATURDAY MORNING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...DLF
AVIATION...DR
AREA FORECAST DISCUSSION
NWS JACKSON KY
153 PM EDT FRI MAY 22 2015
.UPDATE...
ISSUED AT 630 AM EDT FRI MAY 22 2015
BASED ON THE LATEST OBS AND WEB CAMERA IMAGES...HAVE BEEFED UP THE
FOG FURTHER IN THE GRIDS ADDING DENSE TO THE VALLEYS AND SOME
RIDGES. AS A RESULT...ALSO ISSUED AN SPS FOR PATCHY DENSE FOG THAT
NOW RUNS THROUGH 9:30 AM. SENT OUT AN UPDATED SET OF ZONES WITH A
PRE FIRST PERIOD FOR THE FOG. FINALLY...FOR THE GRIDS...TWEAKED
THE NEXT SEVERAL HOURS T/TD GRIDS PER THE LATEST OBS AND TRENDS.
THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 22 2015
07Z SFC ANALYSIS SHOWS HIGH PRESSURE SETTLING INTO THE MID
MISSISSIPPI AND TENNESSEE VALLEYS WITH LOW PRESSURE TO THE NORTH
AND SOUTHEAST. THIS HAS HELPED TO CLEAR THE SKIES THROUGH EASTERN
KENTUCKY AS A NARROW BAND OF LOWER CLOUDS IS HOLDING ON NEAR THE
VIRGINIA BORDER. PATCHY FOG HAS DEVELOPED IN THE VALLEYS EARLY
THIS MORNING IN THE WAKE OF THE CLEARING AND LEFT OVER GROUND
MOISTURE. IN ADDITION...A FEW PATCHES OF DENSE FOG ARE NOTED IN
THE CUMBERLAND VALLEY AND ALSO ON SOME OF THE RIDGES. WILL MONITOR
THIS VIA THE OBS AND WEB CAMS FOR A POSSIBLE SPS OR NPW THIS
MORNING. AT A MINIMUM...THE PATCHES OF DENSE FOG WILL BE
HIGHLIGHTED IN THE MORNING PORTION OF THE FORTHCOMING HWO.
READINGS ARE RATHER CHILLY THIS MORNING...MAINLY IN THE LOWER AND
MIDDLE 40S WHILE DEWPOINTS ARE GENERALLY A DEGREE OR SO LOWER THAN
DRY BULB TEMPS AMID LIGHT NORTHWEST WINDS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH A DEPARTING TROUGH TO
THE NORTHEAST EARLY TODAY FOLLOWED BY RISING HEIGHTS AS A RIDGE
DEVELOPS OVER THE SOUTHEAST PART OF THE NATION. A BAND OF WEAK
MID LEVEL ENERGY WILL LIFT THROUGH KENTUCKY AND INTO THE OHIO
VALLEY FRIDAY NIGHT DURING THIS TRANSITION...BEFORE THE RIDGE
SHARPENS OVER EAST KENTUCKY ON SATURDAY. GIVEN THE MODEL AGREEMENT
HAVE FAVORED THE NAM12 AND HRRR FOR WX DETAILS DUE TO THEIR
HIGHER RESOLUTION.
SENSIBLE WEATHER WILL FEATURE A PLEASANT 48 HOURS AND BEYOND...
ONCE THIS MORNING/S VALLEY FOG...LOCALLY DENSE...BREAKS UP BY 10
AM. TEMPS WILL BE A BIT WARMER EACH DAY WITH A DECENT RIDGE
VALLEY TEMPERATURE SPLIT EXPECTED TONIGHT...BUT MILDER FOR MOST
PLACES THAN EARLY THIS MORNING. HIGH CLOUDS WILL MOVE IN LATER
TODAY AND CONTINUE TO BUILD ON SATURDAY AS A MOSTLY DRY FRONT
SETTLES INTO THE AREA. A STRAY SHOWER CANNOT BE RULED OUT TONIGHT
TO THE NORTHEAST OF THE AREA AS THAT FRONT INITIALLY APPROACHES
BEFORE THE RIDGE ALOFT BUILDS SIGNIFICANTLY OVER THE CWA BY
SATURDAY MORNING.
USED THE SHORTBLEND AS A STARTING POINT FOR THE T/TD AND WIND
GRIDS THROUGH TODAY BEFORE FOLLOWING TO THE SUPERBLEND. DID MAKE
SOME MODERATE TERRAIN BASED CHANGES TO THE LOW TEMPERATURES
TONIGHT. AS FOR POPS...KEPT THEM MINIMAL THROUGH THE PERIOD...IN
LINE WITH MOS GUIDANCE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 AM EDT FRI MAY 22 2015
THE MODELS ARE IN PRETTY GOOD AGREEMENT TO BEGIN THE EXTENDED
PERIOD...WITH A RIDGE OF HIGH PRESSURE BRINGING WARM AND DRY WEATHER
TO THE AREA SATURDAY NIGHT THROUGH LATE IN THE DAY ON MONDAY. IT
LOOKS AS IF THE OHIO AND TENNESSEE VALLEY REGIONS WILL BE FIRMLY
ENTRENCHED IN THE WARM SECTOR OF AN APPROACHING MID LATITUDE
CYCLONE. THE WARM WEATHER WOULD BE IN RESPONSE TO PERSISTENT
SOUTHERLY WINDS SOUTH OF A STRONG NORTHWARD MOVING WARM FRONT.
SHOULD THE MODELS HOLD TRUE...WE WOULD SEE THE RIDGE BEGIN TO BREAK
DOWN MONDAY AFTERNOON AND EVENING...AS A LARGE STORM SYSTEM
APPROACHES FROM THE WEST. THE FIRST PRECIPITATION IS FORECAST TO
MOVE INTO THE AREA BY EARLY MONDAY MORNING AS WARM MOIST AIR OFF THE
GULF OF MEXICO BEGINS TO INTERACT WITH WHAT LOOKS LIKE A PRE FRONTAL
TROUGH. THE PRECIPITATION WILL GRADUALLY INCREASE IN COVERAGE MONDAY
AND MONDAY NIGHT AS THE FRONT INCHES TOWARD THE AREA. THE MODEL DATA
SUGGESTS THAT THERE WILL BE A GOOD CHANCE OF RAIN FROM MONDAY NIGHT
THROUGH EARLY THURSDAY AFTERNOON...AS THE AFOREMENTIONED COLD FRONT
MOVES SLOWLY ACROSS THE REGION...AND PERHAPS EVEN STALLS OUT FOR A
TIME. THE MEMORIAL DAY HOLIDAY AT THIS TIME LOOKS LIKE IT WILL BE
WARM WITH ONLY A SMALL CHANCE OF RAIN ACROSS THE AREA.
TEMPERATURES DURING THE EXTENDED WILL LIKELY BE WELL ABOVE NORMAL
FOR THE TIME OF YEAR...DUE TO PERSISTENT SOUTHERLY FLOW AND
SUBSIDENCE WARMING ASSOCIATED WITH THE RIDGE OF HIGH PRESSURE
MENTIONED EARLIER IN THIS DISCUSSION. HIGHS ARE FORECAST TO TOP OUT
IN THE LOWER 80S THROUGH MID WEEK...WITH OVERNIGHT LOWS IN THE
60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 153 PM EDT FRI MAY 22 2015
A FEW DIURNAL CLOUDS HAVE POPPED UP ACROSS THE REGION...BUT SHOULD
POSE LITTLE TO NO THREAT TO TAF SITES. OTHERWISE...HIGH PRESSURE
RIDGING IS IN CONTROL WITH LIGHT AND VARIABLE WINDS...AND PLENTY
OF SUNSHINE. AS WE HEAD INTO THE NIGHT...LINGERING MOISTURE COULD
LEAD TO SOME PATCHY VALLEY FOG...ESPECIALLY IN AREAS NEAR BODIES
OF WATER. THERE IS SOME UNCERTAINTY CONCERNING IF THIS FOG WILL
MAKE IT INTO THE TAF SITES...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO
REMOVE FROM PREVIOUS TAFS...ESPECIALLY GIVEN THE AMOUNT OF FOG
THAT OCCURRED THE NIGHT BEFORE. EXPECT A SIMILAR SET UP DURING
THE DAY TOMORROW TO THAT OF TODAY...WITH LIGHT WINDS AND THE
POSSIBILITY OF A FEW DIURNAL MID LEVEL CLOUDS. THE ONLY CAVEAT
WILL BE SOME HIGH CLOUDS MOVING INTO THE REGION FROM THE EAST AS
WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1254 PM CDT FRI MAY 22 2015
.AVIATION...
VFR CONDITIONS CURRENTLY AT ALL TAF SITES EXCEPT KHUM...WHERE MVFR
CEILINGS CONTINUE. ALTHOUGH IMPROVEMENT IN CEILINGS IS
ANTICIPATED...CONDITIONS MAY NOT GO VFR AT KHUM UNTIL AROUND
SUNSET. WITH LOWER DEW POINTS IN PLACE...FOG MAY NOT BE MUCH OF AN
ISSUE OVERNIGHT...WITH THE POSSIBLE EXCEPTION OF KHUM. EVEN
THERE...DO NOT ANTICIPATE MUCH WORSE THAN MVFR VISIBILITIES. AS
ONSHORE FLOW RETURNS ON SATURDAY...COULD SEE SOME CLOUDS DEVELOP
NEAR/ABOVE 850 MB...FL050 BY LATE MORNING. 35
&&
.PREV DISCUSSION... /ISSUED 929 AM CDT FRI MAY 22 2015/
UPDATE...
COLD FRONT HAS PUSHED OFF THE SOUTHEAST LOUISIANA COAST TAKING THE
MORE SIGNIFICANT SHOWERS AND THUNDERSTORMS SOUTH WITH THE
BOUNDARY. AN ELEVATED BOUNDARY WITH ISENTROPIC LIFT WAS THE FOCUS
FOR SOME SHOWERS IN AND NEAR THE MISSISSIPPI SOUND. THE FRONTAL
BOUNDARY WILL RETURN BACK NORTH AS A WARM FRONT LATER TODAY AND
ESPECIALLY TOMORROW...HOWEVER SOME OF THE MODELS LIKE THE GFS
APPEAR TOO AGGRESSIVE BRINGING THE FRONT BACK NORTH TO THE I-10/12
CORRIDOR LATE THIS AFTERNOON AND EVENING GIVEN THE FACT THAT THE
DEWPOINTS ARE STILL DROPPING IN SOUTHEAST LOUISIANA COASTAL AREAS.
A BLEND OF THE HRRR AND HIRES WRF MODELS SUGGEST THE ONLY
LOCATIONS THAT MAY SEE SHOWERS AND POSSIBLY A FEW THUNDERSTORMS
WILL BE ALONG THE SOUTHEAST LOUISIANA COAST LATER THIS
AFTERNOON...AND A BLEND OF THE GFS,,,NAM...SREF...AND ECMWF ONLY
SHOW SOME LOW RAIN CHANCES A BIT FURTHER NORTH ALLOWING FOR SOME
SHALLOW ELEVATED CAPE TAKING ADVANTAGE OF SOME ISENTROPIC
LIFT/WEAK WARM AIR ADVECTION OVER THE SHALLOW FRONTAL BOUNDARY.
GIVEN THESE FACTORS AND THOSE MENTIONED IN THE SOUNDING
DISCUSSION...HAVE CUT BACK THE AREAL COVERAGE OF THUNDER TODAY AND
LOWERED THE RAIN CHANCES IN MANY LOCATIONS.
22/TD
SOUNDING DISCUSSION...
REFRESHING BREEZES FROM THE NORTHEAST IN THE LOWEST 1500 FEET WERE
DELIVERING COOLER AND DRIER AIR TO MOST OF THE AREA THIS MORNING
WITH THE EXCEPTION OF LOUISIANA COASTAL PARISHES. THESE NORTHEAST
WINDS HAVE PUSHED THE FRONT JUST OFFSHORE WHERE THERE IS ONGOING
SCATTERED SHOWERS AND THUNDERSTORMS. THERE IS STILL QUITE A BIT OF
MOISTURE IN THE ATMOSPHERE WITH THE PRECIPITABLE WATER VALUE ABOVE
1.75 INCHES. ELEVATED TEMPERATURE INVERSION OF 5C CAPS OFF THE LOW
LEVEL COOLER AIR...WHICH ALONG WITH LIMITED INSTABILITY
/FORECAST CAPE AND LI/ SHOULD LIMIT COVERAGE OF SHOWERS AND
THUNDERSTORMS. WINDS ABOVE 1500 FEET HAVE A WESTERLY COMPONENT AND A
PEAK WIND SPEED OF 59 KNOTS WAS AT 43000 FEET.
12Z BALLOON INFO: A ROUTINE FLIGHT WITH THE ASCENT LASTING 92
MINUTES THIS MORNING. THE BALLOON TRAVELLED 20 MILES DOWNRANGE FROM
THE OFFICE BURSTING EAST OF STENNIS SPACE CENTER AT A HEIGHT OF 21
MILES ABOVE THE GROUND.
ANSORGE
PREV DISCUSSION... /ISSUED 435 AM CDT FRI MAY 22 2015/
SYNOPSIS...
SURFACE MAP REVEALED A STALLED FRONTAL BOUNDARY FROM SOUTH
CAROLINA COAST TO BIG BEND FLORIDA TO SOUTHEAST LOUISIANA COASTAL
WATERS TO SOUTH TEXAS. IN ADDITION...A 1023MB HIGH WAS LOCATED OF
THE MID SOUTH AND ABOUT A 4MB CHANGE FROM THE MCCOMB TO MS DELTA.
NORTH WINDS OF 5 TO 12 KNOTS WERE COMMON ACROSS THE FORECAST AREA
THIS MORNING. MORE SO...DEWPOINT READINGS RANGE FROM THE UPPER
50S OVER SOUTHWEST MS TO NEAR 70 NEAR MS DELTA. PRECIPITABLE
WATER VALUE PLOTS SHOWED A MOISTURE AXIS ALONG TEXAS AND LOUISIANA
COAST WITH VALUES OF 1.6 TO 1.75 INCHES. UPPER AIR CHARTS SHOWED A
LOW OVER SOUTH CALI...A HIGH OVER MEXICO...DIFFLUENT FLOW OVER
WEST TEXAS AND WEAK WEST FLOW OVER LOWER MISSISSIPPI VALLEY. 18
DISCUSSION...
MOISTURE AXIS WILL POOL ALONG THE COAST...WEST OF THE MISSISSIPPI
DELTA TO SOUTH CENTRAL LOUISIANA THIS MORNING THROUGH THIS
AFTERNOON. MID LAYER INSTABILITY IS PRESENT WITH THIS LAYER. AS A
RESULT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FORM IN THIS
GENERAL AREA. DRY AIR AND LESS MOISTURE WITH PW VALUES 1.4 TO 1.5
INCHES OVER MS COAST AND NORTH OF TIDAL LAKES WILL HAMPER
THUNDERSTORM DEVELOPMENT TODAY. COLD AIR ADVECTION WILL LOWER
1000-700MB FROM 3025M TO 2990M ACROSS NORTH ZONES AND 3020M TODAY.
THIS FEATURE ALONG WITH CLOUD COVER WILL HAMPER HIGH SUN ANGLE A
LITTLE BIT TO LOWER HIGHS ABOUT 4 TO 6 DEGREES TODAY. LOWER
DEWPOINTS AND LOWER THICKNESS WILL ALLOW EVENING AND NIGHT TIME
TEMPS ABOUT 6 TO 10 DEGREES FOR SOME LOCATIONS. THE ASSOCIATED
SURFACE HIGH WILL MOVE TO THE EAST COAST BY MIDDAY SATURDAY AND
YIELD A SOUTHEAST FLOW OVER THE PLAINS AND WEST PART OF THE LOWER
MISSISSIPPI VALLEY. HENCE...WEST ZONES WILL SEE INCREASE IN RAIN
CHANCES ON SATURDAY BUT DRY FOR MS COAST ON SATURDAY.
SUNDAY AND THE REST OF THE FORECAST PERIOD WILL HAVE A GOOD
CHANCE OF RAIN IN THE FORECAST. THE MAIN LOW WILL TRACK WEST
ACROSS THE ROCKIES SUNDAY AND OVER THE PLAINS MONDAY. MOISTURE
WILL POOL AHEAD OF THE TROUGH AXIS OVER THE SOUTHERN PLAINS. THE
CLOSE PROXIMITY AND OPEN GULF WILL YIELD LIKELY RAIN CHANCES EACH
AFTERNOON MONDAY THROUGH WEDNESDAY ACROSS THE NORTH AND WEST
ZONES. TROUGH WILL REMAIN OVER THE PLAINS BUT NOT AS SHARP LATTER
PART OF NEXT WEAK. MOISTURE WILL REMAIN ACROSS THE AREA.
THEREFORE...RAIN CHANCES WILL DECREASE BUT NOT MUCH FOR THURSDAY
AND FRIDAY OF NEXT WEEK. 18
MARINE...
COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS MORNING AND
STALL. AS THE FRONT ERODES...WINDS WILL BEGIN TO FRESHEN TO AROUND
15 THEN 15-20KT BY SAT NIGHT OR SUN AHEAD OF THE NEXT SYSTEM
DEVELOPING IN THE OKLAHOMA/NEBRASKA AREA. THIS SYSTEM WILL NOT
MAKE MUCH PROGRESS EASTWARD BUT IT WILL BE ABLE TO KICK OUT A FEW
PREFRONTAL TROUGHS THAT WILL CARRY SH/TS INTO THE NORTHERN GULF BY
TUESDAY. MODERATE WINDS OUT OF THE SE WILL REMAIN THROUGH WED
BEFORE EASING BACK TO A MORE MANAGEABLE 10KT BY THE END OF THE
WEEK.
DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 80 64 86 70 / 10 10 30 20
BTR 81 69 86 72 / 10 10 40 20
ASD 81 67 86 72 / 10 10 20 20
MSY 80 73 86 75 / 20 10 30 20
GPT 82 69 85 75 / 10 10 20 20
PQL 82 63 86 72 / 10 10 10 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
253 PM EDT FRI MAY 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA THIS EVENING WITH HIGH PRESSURE
BUILDING OVERHEAD LATE TONIGHT AND SATURDAY. TEMPERATURES WILL BE
NOTICEABLY BELOW NORMAL WITH SOME FROST POSSIBLE IN THE HIGHER
TERRAIN WELL NORTH AND WEST OF THE METRO. THE HIGH WILL MOVE OFF
THE COAST SUNDAY AND REMAIN IN THE WESTERN ATLANTIC THROUGH MID-
WEEK NEXT WEEK WITH NOTICEABLY HOTTER AND MORE HUMID CONDITIONS
RETURNING TO THE REGION.
&&
.NEAR TERM /THROUGH SATURDAY/...
A CU FIELD AND SCT SHOWERS HAVE DEVELOPED IN VICINITY OF A COLD
FRONT IN CENTRAL PA THIS AFTERNOON. THIS ACTIVITY WILL MOVE
SOUTHWARD INTO MD THIS AFTERNOON. THE HRRR HAS BEEN PERSISTENT
BRINGING ISO-SCT SHOWERS ACROSS THE MASON DIXON LINE BEFORE
SUNSET. DUE TO THE DRY CONDITIONS... COVERAGE WILL BE LOW AND ONLY
A SPRINKLE OR BRIEF SHOWER IS POSSIBLE. NW WINDS 10-15MPH WITH
GUSTS UP TO 25 MPH SHOULD BACK AHEAD OF THE FRONT THIS AFTERNOON
BECOMING SOUTHWEST.
BEHIND THE FRONT...A VERY DRY AIRMASS WILL MOVE INTO THE MID-
ATLANTIC. WINDS WILL BECOME NW AGAIN AND CONTINUE TO SUBSIDE
OVERNIGHT. DRY AND CLEAR CONDITIONS WILL ALLOW TEMPS TO DROP INTO
THE 40S WITH THE EXCEPTION OF THE METROS SEEING THE 50S AND THE
HIGHER ELEVATIONS OF THE ALLGHENY FRONT SEEING THE LOW TO MID 30S.
A FROST ADVISORY HAS BEEN ISSUED FOR THIS REGION.
HIGH PRESSURE MOVES OVERHEAD SATURDAY. NRLY FLOW WILL KEEP TEMPS
BELOW CLIMO IN THE UPPER 60S TO LOW 70S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
SURFACE HIGH PRESSURE WILL DRIFT EAST INTO THE ATLANTIC OCEAN
SATURDAY NIGHT...BUT THE RETURN FLOW WILL BE SLOW AND LOWS WILL
ONLY BE A FEW DEGREES MILDER ON SATURDAY NIGHT AS COMPARED TO
FRIDAY NIGHT. HUMIDITY WILL START TO COME BACK HOWEVER.
OTHERWISE...SKIES SHOULD BE MOSTLY CLEAR AS HEIGHTS ALOFT BUILD
AHEAD OF AN APPROACHING RIDGE.
THE SURFACE HIGH WILL KEEP DRIFTING SLOWLY EAST SUNDAY WITH THE
RETURN FLOW RESULTING IN A NOTICEABLY WARMER AND MORE HUMID DAY AS
COMPARED TO SATURDAY. TEMPERATURES WILL RISE AROUND 10 DEGREES
WHILE DEW POINT RISE WILL BE MORE LIKE 20 DEGREES. SOME CLOUDS MAY
INCREASE IN THE AFTERNOON AS WARM ADVECTION GETS UNDERWAY ALOFT
ALONG THE TAIL END OF A WARM FRONT WHICH WILL MOVE BY TO OUR
NORTHWEST...BUT NO PRECIPITATION IS EXPECTED WITH HEIGHTS
CONTINUING TO BUILD ALOFT AHEAD OF THE STILL APPROACHING AND
BUILDING RIDGE AXIS.
CLOUDS WILL MAKE FOR A MUCH MILDER NIGHT ON SUNDAY NIGHT AS THE
AFOREMENTIONED WARM FRONT PASSES BY TO THE NORTH...BUT AGAIN NO
PRECIPITATION IS EXPECTED. ON MONDAY THE SURFACE HIGH PRESSURE
WILL CONTINUE DRIFTING SLOWLY EAST. TEMPERATURES WILL APPROACH OR
SLIGHTLY EXCEED 90 DEGREES IN MANY AREAS. DEW POINTS STILL WON`T
BE TOO HIGH WITH READINGS PROBABLY STAYING IN THE UPPER 50S IN
MUCH OF THE AREA...BUT IT WILL STILL FEEL CONSIDERABLY MORE
SUMMER-LIKE THAN IT WILL ON SATURDAY. WITH THE RIDGE STILL
BUILDING OVERHEAD...AND DEW POINTS NOT ALL THAT HIGH JUST
YET...CONSENSUS APPEARS TO BE FAVORABLE FOR A STORM-FREE DAY SO
HAVE KEPT THUNDER OUT OF THE FORECAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ECMWF 500 MB RIDGE OVER MID ATLANTIC REGION SLOWLY MOVING TO EAST
ALLOWING A SHORT WAVE TO AFFECT THE REGION THURSDAY. MOISTURE AND
TEMPERATURES WILL GENERALLY INCREASE ON SOUTHWEST FLOW DURING THE
PERIOD. HOT AND HUMID CONDITIONS WILL LEAD TO AN INCREASED CHANCE
FOR THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND EVENING
HOURS EACH DAY.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. NW WINDS
10-15KTS G 20-25KTS WILL SUBSIDE TO 5-10KTS TONIGHT. HIGH PRESSURE
BUILDS INTO THE REGION SATURDAY AND WINDS WILL DIMINISH TO VARIABLE
SAT AFTERNOON THROUGH SATURDAY NIGHT.
THE HIGH WILL MOVE OFF THE COAST SUNDAY AND MONDAY. WINDS WILL
BECOME SOUTHWESTERLY BUT VFR CONDITIONS WILL CONTINUE WITH NO
THUNDERSTORMS EXPECTED. THE RISK FOR STORMS WILL INCREASE TUESDAY
AFTERNOON AND EVENING AS HOT AND HUMID CONDITIONS INCREASE
INSTABILITY.
&&
.MARINE...
W-NW WINDS 10-15KTS G 25KTS WILL CONTINUE ON THE WATERS TODAY.
WINDS WILL SUBSIDE ACROSS THE UPPER TIDAL POTOMAC AND CHESAPEAKE
BAY NORTH OF POOLES ISLAND TONIGHT. HIGH PRESSURE MOVES OVERHEAD
SATURDAY AND NW WINDS WILL BECOME SW BY AFTERNOON ALBEIT 5- 10KTS.
HIGH PRESSURE WILL MOVE OFF THE COAST SUNDAY AND MONDAY WITH A
SOUTHERLY FLOW RETURNING. THE HIGH WILL REMAIN OVER THE WESTERN
ATLANTIC THROUGH THE MIDDLE PORTION OF NEXT WEEK...ALLOWING FOR
THE SOUTHERLY FLOW TO CONTINUE. A SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS MONDAY THROUGH TUESDAY NIGHT DUE
TO THE INCREASING SOUTHERLY FLOW...BUT IT WILL BE MARGINAL DUE TO
THE RELATIVELY COOLER WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EDT SATURDAY FOR
MDZ501.
VA...NONE.
WV...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EDT SATURDAY FOR
WVZ501-503-505.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ531>534-
537-539>543.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ530-
535-536-538.
&&
$$
SYNOPSIS...HAS
NEAR TERM...HAS
SHORT TERM...RCM
LONG TERM...CEM
AVIATION...HAS/RCM
MARINE...HAS/RCM
AREA FORECAST DISCUSSION...UPDATED
NWS PENDLETON OR
1035 AM PDT FRI MAY 22 2015
UPDATED AVIATION DISCUSSION
.UPDATE...ABUNDANT MOISTURE CONTINUES TO RAP AROUND A LOW PRESSURE
SYSTEM OVER CALIFORNIA AND INTO OUR AREA. COMBINING THIS WITH
DAYTIME HEATING WILL CONTINUE TO PRODUCE SHOWERS AND THUNDERSTORMS
THIS AFTERNOON. PWAT REMAINS HIGH AND SOME OF THE STORMS MAY BECOME
STRONG AND PRODUCE HEAVY RAIN ESPECIALLY OVER THE EASTERN HALF OF
THE REGION THAT INCLUDES THE BLUE/WALLOWA MTNS ALONG WITH THE JOHN
DAY HIGHLANDS WHERE A FLASH FLOOD WATCH REMAINS IN EFFECT. IN
ADDITION SOME MODIFICATIONS WERE DONE TO AFTN TEMPS AND THE PRESENT
SHORT TERM FORECAST APPEARS ON TRACK FOR NOW.
&&
.AVIATION...18Z TAFS. IT WILL PREDOMINANTLY REMAIN VFR FOR THE NEXT
24 HOURS...BUT CIGS WILL BE 3500-8000 FEET AGL AND THERE MAY BE
PERIODS OF MVFR WITH SHOWERS AND THUNDERSTORMS. WEB CAMS NEAR KRDM
AND KBDN ARE SHOWING LOW LYING SCUD CLOUDS WITH BASES AROUND 1500
FEET. TOWERING CUMULUS AND/OR CB CLOUDS WILL LIKELY DEVELOP AS THE
DAY PROGRESSES...AND THERE MAY BE IN CLOUD LIGHTNING OR CTG
LIGHTNING. WINDS WILL HAVE A WESTERLY COMPONENT THIS AFTERNOON AT 5-
15 KT...EXCEPT 15 TO 25 KT AT KDLS. WISTER
&&
.PREV DISCUSSION... /ISSUED 300 AM PDT FRI MAY 22 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...A BROAD UPPER LEVEL
TROUGH WILL REMAIN OVER THE REGION THROUGH MUCH OF THIS PERIOD. THE
AIR MASS ACROSS THE REGION WILL REMAIN MOIST AND UNSTABLE TODAY.
INCREASING WEST FLOW FROM THE GORGE SOUTH INTO CENTRAL OREGON WILL
INCREASINGLY LIMIT SHOWER AND THUNDERSTORM CHANCES IN THESE AREAS
LATE THIS AFTERNOON INTO THE EVENING. ELSEWHERE SCATTERED TO
WIDESPREAD SHOWERS WITH ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
POSSIBLE, ESPECIALLY IN THE AFTERNOON AND EVENING. STORM MOTION WILL
BE RELATIVELY SLOW AND DECENT RAINFALL WILL BE POSSIBLE, ESPECIALLY
FROM THUNDERSTORMS. AS THE MAIN SHOWER AND STORM FOCUS LOOKS TO BE
OVER THE EASTERN MOUNTAIN ZONES WILL CONTINUE THE FLASH FLOOD WATCH
COVERING THE OCHOCO-JOHN DAY HIGHLANDS NORTH TO THE BLUE MOUNTAINS
AND NORTHEAST TO WALLOWA COUNTY. A WEAK LOW LOOKS TO SLIDE SOUTH-
SOUTHEAST ACROSS THE REGION TONIGHT. AS A RESULT A DEFORMATION
PRECIP BAND MAY DEVELOP NORTH AND EAST OF THE LOW. AS SUCH WILL KEEP
40-60 PERCENT POPS GOING FROM SOUTH CENTRAL WASHINGTON INTO
NORTHEAST AND EAST CENTRAL OREGON TONIGHT. WESTERLY LOW LEVEL FLOW
WILL CONTINUE TO INCREASE SATURDAY. THUS THE AIR MASS OVER THE
REGION WILL BECOME A BIT DRIER, LIMITING THE AREAS TO BE AFFECTED BY
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. AT THIS
TIME EXPECT SHOWERS/STORMS TO BE MAINLY OVER SOUTH CENTRAL
WASHINGTON AND THE EASTERN MOUNTAIN ZONES. 90
LONG TERM...SUNDAY THROUGH FRIDAY...AN OVERALL DRYING TREND WILL
OCCUR ON SUNDAY WITH NWLY FLOW REGIME BECOMING AT LEAST BRIEFLY
ESTABLISHED OVER THE AREA. THERE WILL STILL BE A SLIGHT CHANCE FOR
AFTERNOON THUNDERSTORMS OVER THE FAR EAST AND ALONG THE WASHINGTON
CASCADE EAST SLOPES. ON MONDAY AN UPPER LOW WILL DROP SWD FROM
BRITISH COLUMBIA INTO WASHINGTON AND BRING A SLIGHT CHANCE FOR
AFTERNOON THUNDERSTORMS EASTERN MOUNTAINS AND WASHINGTON CASCADES.
FROM TUESDAY ONWARD THE MEDIUM RANGE MODELS DIVERGE ON THE HANDLING
OF THE UPPER LOW. THE GFS MEANDERS THE LOW OVER THE FORECAST AREA
KEEPING A CHANCE FOR SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS
EACH DAY THROUGH FRIDAY...WHEREAS THE ECMWF MOVES THE LOW OUT AND
REPLACES IT WITH DRY NW FLOW. FOR NOW HAVE TRENDED THIS FORECAST
UPDATE TOWARD THE GFS WHICH IS IN LINE WITH THE PREVIOUS FORECAST TO
MAINTAIN CONTINUITY. TEMPERATURES WILL BE WARM THROUGH THE PERIOD
WITH HIGHS UPPER 70S TO MID 80S LOWER ELEVATIONS WITH 60S TO LOWER
70S MOUNTAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 74 54 73 51 / 50 40 40 20
ALW 76 56 75 55 / 50 50 30 20
PSC 83 58 80 54 / 40 40 30 10
YKM 78 59 79 55 / 60 40 40 20
HRI 80 57 78 53 / 50 40 30 10
ELN 79 56 78 54 / 60 40 40 20
RDM 68 44 68 39 / 40 20 20 10
LGD 69 54 68 50 / 80 60 40 30
GCD 68 49 69 45 / 80 60 30 20
DLS 76 57 70 54 / 20 20 20 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FLASH FLOOD WATCH THROUGH THIS EVENING FOR ORZ049-050-502-503-
505-506.
WA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WAZ030.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
97/85
AREA FORECAST DISCUSSION
NWS SEATTLE WA
925 AM PDT FRI MAY 22 2015
.SYNOPSIS...A LARGE SURFACE HIGH OFFSHORE WILL MAINTAIN MODERATE TO
STRONG LOW LEVEL ONSHORE FLOW OVER WESTERN WASHINGTON THROUGH MID
NEXT WEEK. THIS WILL MAINTAIN THE PATTERN OF MORNING CLOUDS WITH
PARTIAL AFTERNOON CLEARING. WEAK LOW PRESSURE ALOFT WILL BRING A
CHANCE OF SHOWERS...MAINLY OVER THE MOUNTAINS AFTERNOON AND EVENINGS.
&&
.SHORT TERM...THE LARGE NE PACIFIC SURFACE HIGH WILL BE DOING ITS
DOMINANT THING FOR THE NEXT WEEK...MAINTAINING MODERATE TO STRONG
ONSHORE FLOW ACROSS W WA. THIS MORNING THE HIGH IS CENTERED OUT
ALONG 135W TO 140W AND WILL PROBABLY REMAIN THERE FOR THE NEXT
SEVERAL DAYS. CLOUD BASES WERE AROUND 1000 FEET THIS MORNING WITH
TOPS AROUND 3000 FEET. LOW LEVEL FLOW WILL REMAIN ONSHORE ALL DAY SO
LITTLE IF ANY BREAKOUT IS EXPECTED.
THE AIR MASS ALOFT IS UNSTABLE AND E FLOW HAS ALLOWED SOME SHOWERS
TO DRIFT OUT OVER THE INTERIOR LOWLANDS MAINLY S OF PUGET SOUND...AS
WELL AS OVER THE OLYMPICS. THERE HAS BEEN SOME PERSISTENT SPORADIC
LIGHTNING AROUND SHELTON. FORECASTS HAVE BEEN UPDATED FOR THIS. THE
HRRR STILL SHOWS THIS ACTIVITY DIMINISHING LATE THIS MORNING.
MODELS CONTINUE TO SHOW CONVECTION BREAKING OUT OVER THE CASCADES
AND OLYMPICS THIS AFTERNOON AND EVENING. AT THIS
POINT...THUNDERSTORMS ARE ONLY FORECAST FOR AROUND THE CASCADE
CREST. FLOW ALOFT IS WEAKLY SE SO THERE IS STILL A CHANCE THAT SOME
CELLS COULD DRIFT W OVER THE LOWLANDS THIS EVENING. THE MAIN CONCERN
IS THE CHANCE OF SHOWERS AND POSSIBLY A WANDERING THUNDERSTORM OVER
THE LOWLANDS E OF PUGET SOUND.
MODELS SHOW A WEAK UPPER LEVEL TROUGH REMAINING JUST OFFSHORE
THROUGH TONIGHT...THEN DRIFTING INLAND OVER W WA ON SATURDAY. THE
TROUGH SLIDES OVER E WA ON SUNDAY...BUT THEN AN UPPER LEVEL CLOSED
LOW MOVES SE OVER W WA ON MONDAY. THIS WILL KEEP WEAK LOW PRESSURE
OVER THE AREA AND MAINTAIN A GENERALLY UNSTABLE AIR MASS ALOFT INTO
NEXT WEEK. THE PATTERN OF AFTERNOON AND EVENING CONVECTION OVER THE
MOUNTAINS WILL CONTINUE. THUNDERSTORMS ARE MOST LIKELY OVER THE
CASCADES BUT THERE IS PROBABLY A VERY LOW NON-ZERO CHANCE OF
THUNDERSTORMS FOR THE OLYMPICS. DAY-TO-DAY CHANGES IN THE MID LEVEL
STEERING FLOW WILL DETERMINE WHETHER ANY CELLS WILL MAKE IT OVER THE
LOWLANDS. KAM
.LONG TERM...PREVIOUS DISCUSSION FROM THE 320 AM AFD...THE GENERAL
PATTERN WILL CHANGE VERY LITTLE MONDAY THROUGH THURSDAY. A WEAK
UPPER TROUGH WILL BE OVER THE PACIFIC NORTHWEST WITH LOW LEVEL
ONSHORE FLOW. THERE SHOULD BE MORNING CLOUDS AND SOME AFTERNOON
SUNSHINE EACH DAY WITH A CHANCE OF SHOWERS... MAINLY OVER THE
MOUNTAINS AFTERNOON AND EVENING HOURS. HIGHS WILL BE NEAR OR
SLIGHTLY ABOVE NORMAL. SCHNEIDER
&&
.AVIATION...WRN WA WILL REMAIN UNDER THE INFLUENCE OF A WEAK
ELONGATED UPPER LOW CENTERED OVER WRN BRITISH COLUMBIA THRU
TONIGHT. THE FLOW ALOFT WILL REMAIN LIGHT SLY. CONTD LOW LEVEL
ONSHORE FLOW. THE AIR MASS WILL DESTABILIZE FURTHER THIS AFTERNOON
FOR A FEW TSTMS OVER MAINLY THE MTNS. THE TSTM THREAT SHOULD END
AFTER 0300 UTC.
MEANWHILE...CIGS MAINLY AOB 1K FT BLANKETED MUCH OF THE LOWLANDS
THIS MORNING. TOPS WERE GENERALLY IN THE 2500 TO 3500 FT RANGE.
THERE WERE ALSO AREAS OF 4-6SM /DUE TO FOG/ OVER THE COAST THIS
MORNING. THE FOG SHOULD DSIPT BY 2000 UTC. ANTICIPATE CIGS TO
GRADUALLY LIFT DURING THE DAY. BY 0000 UTC...CIGS SHOULD BE MAINLY
IN THE MVFR CATEGORY /1-3K FT/ RANGE OR BETTER.
KSEA...CIGS WILL LIFT INTO THE 2-3K FT RANGE AFTER 1900 UTC...AND
ARE ANTICIPATED BE NEAR 3500 FT BY 0000 UTC. CIGS WILL LOWER INTO
THE 1-2K FT RANGE AFTER 0600 UTC. WINDS WILL GENERALLY BE SW 5-10
KT.
&&
.MARINE...
THE WEST COMPONENT OF THE PRES GRADIENT CONTINUED TO WEAKEN THIS
MORNING. IT SHOULD PICK BACK UP THIS AFTERNOON BUT VERY CONFIDENT
THAT SPEEDS WILL REACH GALE FORCE OVER PARTS OF THE STRAIT OF JUAN
DE FUCA THIS EVENING. WILL RE-EVALUATE THE SITUATION THIS
AFTERNOON.
MEANWHILE...PERSISTENT HIGH PRES OFFSHORE WITH LOWER PRES INLAND
WILL RESULT IN CONTINUED ONSHORE FLOW OF VARYING STRENGTH
THROUGH TUE.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING IN EFFECT TIL 5 AM SATURDAY FOR THE CENTRAL AND
EASTERN STRAIT OF JUAN DE FUCA.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
903 AM PDT FRI MAY 22 2015
.SYNOPSIS...
The Memorial Day Weekend is expected to be warmer than average
with afternoon temperatures in the 70s and 80s. Look for scattered
showers and thunderstorms this weekend into next week. Some
thunderstorms will be capable of producing heavy downpours and
frequent lightning.
&&
.DISCUSSION...
Rest of today: The main changes have been to adjust the areal
coverage of pcpn and sky cover based on the radar loops, vsbl
satellite and sfc obs. The flash food watch for the E Slopes of
the Cascades will remain en effect for recent burn
scars...including the Carlton complex...Mills Canyon...and the
chiwaukum complex. However, given the easterly flow....the
strongest storms are anticipated along the crest of the Cascades.
Blended PW shows anomalous moisture over the Cascades. Slow
steering flow will also help to produce localized, prolonged heavy
downpours. It still looks like the potential for thunder this
afternoon is on track for most of the rest of Ern wa and the Cntrl
Idaho Panhandle as well. The exception may be the N Idaho
Panhandle where the cap is a bit stronger. The high CAPE/weak deep
layer shear profiles support an enhanced heavy downpour threat for
most thunderstorms this afternoon and evening. Small hail is also
possible. The highest threat areas will be near the Cascades as
well as the Lewiston/Pullman region and the Cntrl Idaho
Panhandle. bz
&&
.AVIATION...
12Z TAFS: Scattered high based showers will continue to drift
west from the vcnty of KMWH toward the KEAT area this morning,
with mainly light rain expected. Convection will again develop
late today, after 20z. Expect a similar trend as experienced on
Thursday with activity starting in the Blue mountains and Camas
Prairie and than drifting west toward the Cascades. Today
anticipate more development in the Cascades under the easterly
low level flow and the approaching shortwave from the northwest.
The HRRR shows convection will begin to fire over the high terrain
of the Cascades and Blue Mountains after 20z Fri. Gusty outflow
winds and brief heavy rain will be the main threats from
thunderstorms, which should decrease after 03z. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 82 53 80 53 79 53 / 10 10 10 10 20 30
Coeur d`Alene 81 52 79 53 79 52 / 10 10 10 10 20 30
Pullman 78 49 73 47 75 49 / 20 10 10 10 10 10
Lewiston 81 56 79 54 82 56 / 30 20 20 20 20 20
Colville 86 53 83 55 82 52 / 10 10 10 10 30 30
Sandpoint 81 50 80 48 77 50 / 10 0 10 10 20 20
Kellogg 81 50 79 49 78 50 / 20 10 30 20 20 20
Moses Lake 84 56 84 55 83 54 / 40 10 10 10 20 20
Wenatchee 82 59 83 58 82 57 / 60 30 10 10 20 20
Omak 86 53 85 54 83 53 / 20 20 10 10 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch from 1 PM this afternoon to 8 PM PDT this
evening for East Slopes Northern Cascades.
&&
$$