[top]
000
FXUS61 KLWX 220021
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
821 PM EDT TUE MAY 21 2013
.SYNOPSIS...
OFFSHORE HIGH PRESSURE WILL CONTINUE TO BRING WARM MOIST SOUTHERLY
AIR INTO THE REGION THROUGH THURSDAY. AFTERNOON AND EVENING
THUNDERSTORMS ARE POSSIBLE EACH DAY. A COLD FRONT WILL PASS
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. COOLER CONDITIONS
ARE EXPECTED OVER THE WEEKEND.
&&
.NEAR TERM /TONIGHT/...
LN OF TSTMS PRNTLY ENTERING WRN W.V. WL LKLY WEAKEN B4 GETTING TO
THE ERN PART OF THE STATE.
LGT FOG PSBL AFTR MDNGT...MOST PREVALENT RIGHT B4 SUNRISE AND THEN
QUICKLY BURNING OFF. LOWS IN THE 60S XCPT L70S IN THE CITIES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
CWFA WL BE WARM SECTOR THRU PD...AS SFC HIGH WELL OFF ERN SEABOARD
AIDS SLY FLOW/MOISTURE ADVECTION. THUS AMS WL REMAIN UNSTBL...W/
POPS GNLY INCREASING IN RESPONSE TO DROPPING MID LVL HGTS. WL STILL
HV A DIURNAL TREND TO STORMS. THU LOOKS TO BE THE BETTER DAY IN
TERMS OF TSRA DVLPMNT AS CDFNT/UPR LOW DROPS THRU GRTLKS. HV
RAISED POPS BOTH DAYS AND INTRODUCED LKLYS ON THU.
SPC HAS WRN MD/HIGHLANDS OUTLOOKED IN SLT RISK THU AHD OF THE CD
FNT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
CFP THU NGT. AFTR THAT THE NEXT SVRL DAYS LOOKING GOOD AS CANADIAN
HIGH PRESSURE BUILDS IN WITH TEMPS 5-10 DEGREES BELOW NORMAL.
SHORTWAVE OVER THE TN VLY ON SUNDAY SHOULD REMAIN WEST OF THE LWX
CWA...WILL HAVE TO MONITOR FOR INCREASED POPS. AS OF NOW EXPECT
SOME HIGH CLOUDS SUNDAY WITH A WARMING TREND STARTING THAT
CONTINUES INTO MID NEXT WEEK.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDS AT ALL TERMINALS. XPCT AREAS OF LOW CLOUDS/FOG TO DVLP
LT TNGT...CONTG INTO THE WED MRNG PUSH BUT DISSIPATING AFTR
SUNRISE. THIS TIME HV LEANED MORE TWD FOG DVLPMNT INLAND SINCE
SKIES WL BE PRTLY CLR SUPPORTING RADL COOLING DOWN TO MOIST
DEWPTS. HWVR LOW CLDS WL BE LURKING JUST E OF DCA/BWI.
DIURNAL THUNDERSTORM ACTIVITY WED/THUR WITH IFR CONDS POSSIBLE IN
THE HEAVIEST ONES. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY
FLOW WITH CLEAR CONDS SATURDAY. JUST SOME HIGH CLOUDS ON SUNDAY.
&&
.MARINE...
THE PRESSURE GRADIENT WILL STRENGTHEN OVER THE REGION WED AFTN AND
NGT AS LOPRES MOVES THRU THE GREAT LAKES AND HIPRES REMAINS PARKED
OVER THE WRN ATLANTIC. SLY RETURN FLOW WILL INCREASE ACCORDINGLY
BETWEEN BOTH SYSTEMS. A SCA GOES IN EFFECT WED AFTN FOR THE WATERS
THAT ARE MOST PRONE TO SLY CHANNELING IN THE MID CHSPK BAY AND
LWR/MID TIDAL POTOMAC RVR. SCA EXPANDS WED NGT TO INCLUDE ALL OF THE
MD CHSPK BAY AS A SLY NOCTURNAL JET DEVELOPS.
SLY FLOW WITH HIGH PRESSURE OFFSHORE AHEAD OF A COLD FRONT THAT
COMES THROUGH THURSDAY NIGHT. SLY CHANNELING TO 20 KT POSSIBLE WED
EVENING...AND THURSDAY. NWLY FLOW TO 20 KT POSSIBLE FRIDAY. LIGHT
AND VARIABLE FLOW THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
EXPECT POSITIVE TIDAL ANOMALIES TO DEVELOP DURING THE MIDWEEK AS SLY
FLOW STRENGTHENS. CBOFS GUIDANCE...WHICH HAS VERIFIED FAIRLY WELL OF
LATE...FCST WATER LEVELS TO STAY BELOW MINOR COASTAL FLOODING
THRESHOLDS THRU AT LEAST THU MRNG.
COLD FRONT MOVES THRU ERY FRI MRNG. WLY WINDS BEHIND THE FRONT
SHOULD ERASE ANY POSITIVE TIDAL ANOMALIES.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ530-531-539.
SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ532>534-536-537-540>543.
&&
$$
UPDATE...WOODY!
[top]
000
FXUS61 KAKQ 220019
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
819 PM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO THE REGION
THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE MID ATLANTIC
THURSDAY NIGHT. HIGH PRESSURE RETURNS TO THE AREA FRIDAY INTO THE
WEEKEND WITH DRIER CONDITIONS AND COOLER TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SHOWERS HAVE COME TO AN END ACROSS SE VA AND NE NC...AND THE ONLY
REMAINING SHOWERS ARE JUST OFF THE VIRGINIA BEACH COAST. THIS AREA
OF SHOWERS IS EXPECT TO DIE OUT IN THE NEXT 1 TO 2 HOURS WITH THE
LOSS OF DAYTIME HEATING. SKIES ARE MOSTLY CLEAR FOR MOST OF THE FA
EXCEPT FOR SOME HIGH CIRRUS STREAMING DOWN INTO FAR NW COUNTIES
ATTM FROM THE NORTH.
FOR OVERNIGHT...THE COMBINATION OF AMPLE LOW LEVEL MOISTURE AND
CLEARING THIS EVENING WILL RESULT IN THE DEVELOPMENT OF LOW
STRATUS AFTER MIDNIGHT TONIGHT. ONCE AGAIN...S-SW WINDS AT OR
ABOVE 5 KT WILL PREVENT FOG FROM FORMING. HOWEVER IF ANY
OBSERVATION SITES REPORT VISIBILITIES LOWER THAN 7 STATUTE
MILES...THE OBSCURATION WILL LIKELY BE MORE HAZE THAN FOG/MIST
(VERY SIMILAR TO MONDAY NIGHT). TEMPS WILL REMAIN WELL ABOVE
NORMAL TONIGHT WITH LOWS IN THE MID TO UPPER 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
SIMILAR PATTERN AS LAST COUPLE DAYS WILL CONTINUE INTO WED. SW
FLOW ALOFT RESUMES AFTER A MID-LVL LO PUSHES OFFSHORE TNGT.
DEEP LAYER MOISTURE WILL THEN SLOWLY INCREASE WED INTO WED NGT
AHEAD OF A LO PRES SYSTM PASSING THRU THE GREAT LAKES REGION. DID
INCLUDE A SLGT CHC FOR A SHWR/TSTM WED AFTN/EVENG WITH A WARM AND
MOIST AIRMASS IN PLACE...HOWEVER MOST AREAS SHUD REMAIN DRY DUE TO
A LACK OF FORCING. OTW...EXPECT A PRTLY CLDY SKY WITH HIGHS IN THE
MID 80S.
FOR THU...COLD FRNT APPROACHES FROM THE OH VALLEY...AND RAIN
LIKELY WITH INCREASING MOISTURE AND S/W ENERGY ALOFT. UP TO A HALF
INCH OF PRECIP PSBL WITH THE BEST CHC FOR RAIN IN THE AFTN. HI
TEMPS GENRLY IN THE LO 80S. READINGS WILL BE A BIT COOLER NEAR
THE COAST. THE RAIN WILL END FROM WEST TO EAST THU NGT/FRI MRNG AS
THE COLD FRNT ADVANCES OFF THE COAST. NOT EXPECTING SKIES TO
COMPLETELY CLR OUT...WITH MOISTURE STILL IN PLACE ALOFT FOLLOWING
THE SFC FROPA.
DRIER CONDS EXPECTED BY FRI AFTN AS FLOW BECOMES NWLY FOR THE
FIRST TIME IN SEVERAL DAYS...AND TEMPS ONLY REACHING THE MID 70S
IN MOST LOCATIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI NIGHT. CLRG
& COOL WITH DECOUPLING WINDS INLAND. CSTL WNDS STAY MIXED DUE TO LOW
PRS SLOWLY PULLING AWAY TO THE NE. LOWS M-U40S FROM I95 ON W...
NEAR 50 INVOF CHES BAY AND L-M50S AT THE COAST.
SUNNY & PLEASANT SAT WITH H5 RIDGE OVRHD. HIGHS IN THE L-M70S XCPT
60S AT THE BEACHES. PT CLDY SAT NITE AS SOME HIGH LVL MSTR OVRSPRDS
RGN. LOWS 50-55. PT SUNNY AND A BIT WRMR SUN. HIGHS M-U70S XCPT
65-70 AT THE BEACHES.
TRICKY FCST ERLY NEXT WEEK. MODELS NOW INCRG MSTR DUE TO COMBO OF
ONSHORE E-SE FLOW AND WRM FRNT APPRCHG FROM THE SW. APPEARS BEST
SPRT FOR POPS WILL BE ACROSS SRN & WRN VA/NRN NC MONDAY & MON
NITE. KEPT SLGHT CHC POPS ON TUE FOR NOW GIVEN THE LOW CONFIDENCE
THIS FAR OUT. HIGHS MON L-M70S. LOWS 55-60. HIGHS TUE M-U70S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS HAVE ENDED ACROSS SE VA AND NE NC THIS
EVENING. NEXT CONCERN WILL BE THE FORMATION OF IFR STRATUS
OVERNIGHT. LATEST GUIDANCE HAS CIGS BECOMING IFR AT ALL TAF SITES
EXCEPT KECG BETWEEN 06-08Z WED MORNING AND CONTINUING THROUGH
14-15Z. WILL MAINTAIN MVFR CIGS FOR KECG OVERNIGHT. CONDITIONS
WILL SLOWLY IMPROVE WEDNESDAY MORNING. AN ISOLATED SHOWER OR
THUNDERSTORM IS POSSIBLE WED AFTN.
OUTLOOK: IFR STRATUS WILL BE PSBL AGAIN THURSDAY MORNING. MORE
WIDESPREAD CONVECTION IS EXPECTED THURSDAY AFTN AND EVENING AS A
COLD FRONT APPROACHES. THE WEATHER IMPROVES LATE FRIDAY AND BEYOND
FOLLOWING A COLD FRONTAL PASSAGE.
&&
.MARINE...
NO HEADLINES IN SHORT TERM AS WINDS REMAIN S-SW AOB 15KT THRU WED.
SOME CHANNELING UP THE BAY AS WELL AS SEAS APPRCHG 5 FT OUT NR 20 NM
INVOF BUOY 44009 BY WED NITE...BUT CONFIDENCE NOT HIGH ENUF TO GO
WITH A SUSTAINED SCA SO WILL HOLD OFF ON HEADLINES ATTM. SCA`S MAY
EVENTUALLY BE NEEDED FOR SEAS OVR NRN CSTL WTRS.
CDFRNT CROSSES THE WATERS LATE THU NITE FRI WITH LOW PRS MOVG N
ALONG IT. WILL HAVE TO MONITOR PRS GRDNT BTWN THIS LOW AND STRONG
HIGH PRS BLDG IN FROM THE NW FOR PSBL SCA CNDTNS FRI INTO FRI EVE.
OTW...HIGH PRS BUILDS INTO THE AREA OVER THE WEEKEND WITH SUB SCA
CNDTNS XPCTD BOTH SAT AND SUN.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD/MAS
NEAR TERM...BMD
SHORT TERM...MAS
LONG TERM...MPR
AVIATION...JDM/LSA
MARINE...MPR
[top]
000
FXUS61 KPHI 220013
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
813 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEASTERN UNITED STATES
COAST THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL MOVE FROM THE
SOUTHERN PLAINS TO SOUTHEASTERN CANADA THROUGH THURSDAY AND BRING
A COLD FRONT THROUGH THE REGION LATE THURSDAY INTO FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST FOR THE HOLIDAY WEEKEND
THIS HIGH WILL THEN GRADUALLY MOVE OFFSHORE THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
740 PM: NO CHANGE TO THE ESTF UPDATE AT 550 PM.
STARTED THE EVENING MOSTLY CLEAR AND CUT OUT THE CHANCE OF SHOWERS
AND TSTMS PRIOR TO MIDNIGHT. THE ACTION IN MONROE AND SUSSEX
COUNTIES AROUND 2PM WAS ALL THAT WE WOULD HAVE TODAY.
THERE IS A SMALL CHANCE THAT ISOLATED CONVECTION WILL DEVELOP OR SLIDE
INTO NE PA TOWARD 04Z AND INVADE THE POCONOS AROUND 05Z BUT FOR NOW...
MODEL SIGNALS ARE DRY FOR THIS EVENING AND WITHOUT CU...ITS
DIFFICULT TO HAVE A SHOWER.
THE FOG WAS DELAYED TIL LATE AND ATTM...NOT CALLING IT 1/4MI
DENSE. WILL REREVIEW FOG POTENTIAL LATER THIS EVENING.
LOW OVC WITH AREAS OF FOG SHOULD TEND TO BECOME WIDESPREAD AFTER
07Z. CONDITIONS WILL PROBABLY REMAIN ABOVE DENSE FOG ADVISORY
CRITERIA...SO WE HAVE NOT ISSUED. IT WILL REMAIN WARM AND HUMID
AGAIN TONIGHT WITH LOWS IN THE LOW/MID 60S NORTH AND MID/UPPER 60S
SOUTH. WINDS LIGHT MOSTLY FROM THE SW.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
WEDNESDAY WILL HAVE WEATHER SIMILAR TO TODAY. PLENTY OF CLOUDS/FOG IN
THE MORNING AND A CHC FOR SHOWERS/TSTMS DURING THE AFTERNOON...MAINLY
E PA. ITS POSSIBLE THERE WILL BE ISOLATED SHOWERS IN THE DE VALLEY
DURING MIDDAY BUT FOR THE MOST PART CONVECTION SHOULD BE MID OR
LATE AFTN...IF ANY IN OUR CWA.
SPC HAS PLACED THE SLGT RISK FOR TSTMS TO THE WEST OF OUR AREA...SO
WE WILL WATCH FOR THE UPDATE EARLY WEDNESDAY MORNING. HIGHS WILL BE
VERY WARM AGAIN WED WITH TEMPS IN THE MID TO UPPER 80S IN MOST AREAS
(EXCEPT ALONG THE SHORE...WHERE READINGS IN THE UPPER 70S TO LOW
80S MAY OCCUR). THERE IS STILL A SMALL CHANCE THE TEMP NUDGES 90F
VCNTY OF KRDG OR KABE OR NEAR KSMQ IN THE AFTN WHERE THE HOTTEST
TEMPS SHOULD OCCUR.
CLOUD COVER WILL PROBABLY VER SLOW TO THIN OVER SE NJ AND S DE ON
WEDNESDAY...POSSIBLY NOT CLEARING OFF TIL MID AFTN.
SW WIND G TO 15 MPH WED AFTN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE AREA OF HIGH PRESSURE WILL REMAIN OFF THE ATLC CST WED NIGHT
AND THU AND SWLY FLOW WILL CONTINUE WHICH WILL KEEP WARM WX OVER
THE AREA. HOWEVER, BY THU, AN AREA OF LOW PRESSURE WILL MOVE INTO
SERN CANADA. THE CDFNT ASSOCD WITH THIS LOW WILL CROSS THE REGION
THU NIGHT. THIS PD LOOKS TO TO BE THE WETTEST WITH SHOWERS, TSTMS
AND PSBLY SOME HEAVY RAIN. ITS A BIT TOO EARLY TO BE CERTAIN ABOUT
ANY SEVER WX POTENTIAL. IT WILL BE DEPENDENT ON DAYTIME HEATING
AND OTHER FACTORS. HOWEVER, IT COULD BE MITIGATED BY THE FACT THAT
THE FRONT WILL BE COMING THROUGH AFTER SUNSET. THE 21/12Z GFS IS
THE SLOWEST MDL CLEARING THINGS OUT ON FRI AND TRIES TO DEVELOP A
WAVE ALG THE FRONT. NONE OF THE OTHER MDLS HAVE THIS FEATURE, SO
AM NOT INCLINED TO GO ALONG FOR NOW. FRI, ESPECIALLY LATER FRI,
SHOULD SEE IMPROVING WX AND BY SAT A LARGE AREA OF HIGH PRESSURE
WILL PUSH INTO THE MIDWEST FROM CANADA WAND WILL SLOWLY SLIDE EWD
THRU THE HOLIDAY WEEKEND.
THE PGRAD BETWEEN THE BUILDING HIGH AND THE DEPARTING LOW OVER THE
CANADIAN MARITIMES WILL KEEP A DECENT NWLY FLOW OVER THE AREA ON
SAT, WITH WEAKENING FLOW AS THE HIGH MOVES IN ON SUN. SO, AT THIS
POINT, THE WEEKEND LOOKS PREDOMINANTLY DRY, ALBEIT COOL FOR LATE
MAY AND WITH A BRISK NW WIND, IT WILL FEEL COOLER ON SAT.
TEMPS LOOK TO BE WARMEST ON THU, WITH TEMPS AROUND 80 OR INTO THE
80S. THEN BEHIND THE FRONT MOST LOCATIONS WILL BE AROUND 70 OR
INTO THE LOWER 70S FOR THE REMAINDER OF THE PD. SAT LOOKS TO BE
THE COOLEST DAYS, WITH MANY LOCATIONS HOVERING IN THE MID/UPPER 60S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR CIRRUS THIS EVENING. LIGHT SSW WIND. CONDITIONS
LIKELY TO BECOME IFR OR LIFR IN ST/FOG AFTER 07Z.
WED...AFTER A PROBABLE IFR CONDITION START AT 12Z...A SLOW RETURN TO
VFR BY MID OR LATE MORNING WITH SCT-BKN CLOUDS AOA 3500 FT IN THE
AFTN AND A SHOWER OR TSTM POSSIBLE DURING THE AFTERNOON...MAINLY
VCNTY KRDG OR KABE. SW WIND GUST TO 15 KT IN THE AFTN.
THE IFR CIGS MAY BE VERY SLOW TO LIFT VCNTY KMIV AND KACY NOT
LIFTING TO MVFR CIGS TIL MIDDAY WED AND CLEARING AROUND MID AFTN.
THERE IS A SMALL CHANCE FOR A SHOWER IN THE DE VALLEY VCNTY
KPNE/KPHL AROUND 15-16Z WED PER LONG RANGE RUC-RAP BUT UNLIKELY.
FEELING IS THE MODELS HAVE A SLIGHT WET BIAS AND OVERDOING
CONVECTIVE POTENTIAL IN THIS SW FLOW SUMMERLIKE SCENARIO.
OUTLOOK...
WED NIGHT THROUGH THU NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE IN ANY SHOWERS AND THUNDERSTORMS OR PDS OF
HEAVY RAIN. WIND WILL SHIFT FROM SW TO NW BEHIND CFP LATE WED
NIGHT/EARLY THU MRNG. HIGH CONFIDENCE ON THE OVERALL DETAILS. LOW
CONFIDENCE ON THE FACT THAT ALL SITES WILL SEE MVFR/IFR AND
TIMING.
FRI...MAINLY VFR WITH A CHANCE OF SHOWERS MAINLY IN THE MORNING.
HIGH CONFIDENCE.
SAT-SUN...VFR CONDITIONS EXPECTED. A BRISK NW WIND ON SAT OF 15-20
KT. HIGH CONFIDENCE.
&&
.MARINE...
WINDS HAVE BEEN MOSTLY SW/S ACROSS THE WATERS TODAY WITH SPEEDS
MOSTLY 10 TO 15 KTS. SEAS HAVE BEEN MOSTLY AROUND 3 FT ON THE OCEAN
AND 1 TO 2 FT OVER THE DEL BAY. CONDITIONS SHOULD REMAIN SUB-SCA
TONIGHT AND APPROACH SCA LATER WEDNESDAY. WINDS WILL INCREASE
WED...BUT WITH THE WARMER AIR AND COOLER SEAS...THE WINDS/WAVE
GUIDANCE MAY BE TOO HIGH. WE OPT TO KEEP THE SEAS AT 3 TO 4 FT FOR
WED AND HOLD THE WINDS BELOW SCA FLAG LEVELS. A FEW G 20-25 ARE NOT
OUT OF THE QUESTION LATER WED. SCAT SHOWERS/TSTMS EXPECTED WED.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WED NIGHT THROUGH
THU. AS THIS FLOW STRENGTHENS WITH A CDFNT APPROACHING FROM THE W
ON THU, WINDS AND SEAS WILL GRADUALLY INCREASE. THEREFORE, SEAS
AND WIND COULD BE AOA SCA CRITERIA BY THE START OF THE OUTLOOK PD. A
SMALL CRAFT ADVISORY MAY BE NEEDED FOR THIS PD ON THE OCEAN FRONT.
HOWEVER, WITH VERY WARM AIR OVER THE RELATIVELY COOL OCEAN AND
WAVE WATCH OVERDOING HEIGHTS OF LATE, HAVE DECIDED NOT TO POST
ANYTHING ATTM. THERE WILL ALSO BE SOME SHWRS/TSTMS WED NIGHT INTO
THU ALG AND AHEAD OF THE CFP.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SCA CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW CRITERIA THROUGH
THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION.
&&
.CLIMATE...
KNOWING THE FIRST 20 DAYS OF MAY TEMPERATURES HAVE AVERAGED ALMOST
SPOT-ON NORMAL FOR ALMOST EVERY CLIMATE SITE IN OUR AREA...WE
PROJECTED THE REMAINDER OF THE MONTH FOR KPHL. WE USED THE KPHL
MAX/MINS FOR THE NEXT 7 DAYS, AND THEN THE FTPRHA 2M MAX/MIN TEMPS
BEYOND THRU THE 31ST.
THE AVG IS IN THE NORMAL RANGE...SLIGHTLY ABOVE BUT WITHIN 1/2 DEG
OF NORMAL.
WE DISCUSS TEMPERATURES TONIGHT SINCE WE`RE COMING INTO THE MEMORIAL DAY
WEEKEND WHICH WILL BE COOL AND LESS FAVORABLE FOR SWIMMING BUT GUIDANCE
IS SHOWING INCREASING CHANCES OF A WARMER THAN NORMAL PATTERN DEVELOPING
BETWEEN ROUGHLY THE 30TH OF MAY INTO THE FIRST WEEK OF JUNE.
SST`S ARE ALREADY GENERALLY SEVERAL DEGREES ABOVE NORMAL. IF WE
ADVANCE INTO A HOT SPELL BY THE END OF NEXT WEEK...WE DO NOT WANT
A REPEAT OF LAST YEAR WHEN HOT WEATHER...WARM WATERS AND SEEMINGLY
BENIGN OCEAN SWELLS ENCOURAGED SWIMMERS TO TAKE UNNECESSARY RISKS
AT EARLY SEASON "UNGUARDED" BEACHES WITH RIP CURRENT RELATED
DROWNINGS. THE DANGERS OF RIP CURRENTS ARE WORTHY OF A FEW MINUTES
OF DINNER TABLE DISCUSSION...ESPECIALLY SINCE THERE IS ACCESS TO
THE BEACHES FOR MILLIONS OF SWIMMERS OVER INTERIOR SECTIONS OF OUR
AREA WHO MAY BE LESS EXPERIENCED WITH THE DANGERS OF OCEAN SWIMMING.
THE CHANCES OF DROWNING AT A LIFE GUARDED BEACH IS 1 IN 18 MILLION.
RIP CURRENT AWARENESS WEEK IS JUNE 2 THROUGH 8.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...DRAG 813
SHORT TERM...DRAG/O`HARA 813
LONG TERM...NIERENBERG
AVIATION...DRAG/NIERENBERG 813
MARINE...DRAG/NIERENBERG/O`HARA
CLIMATE...DRAG
000
FXUS61 KAKQ 220012
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
812 PM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO THE REGION
THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE MID ATLANTIC
THURSDAY NIGHT. HIGH PRESSURE RETURNS TO THE AREA FRIDAY INTO THE
WEEKEND WITH DRIER CONDITIONS AND COOLER TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SHOWERS HAVE COME TO AN END ACROSS SE VA AND NE NC...AND THE ONLY
REMAINING SHOWERS ARE JUST OFF THE VIRGINIA BEACH COAST. THIS AREA
OF SHOWERS IS EXPECT TO DIE OUT IN THE NEXT 1 TO 2 HOURS WITH THE
LOSS OF DAYTIME HEATING. SKIES ARE MOSTLY CLEAR FOR MOST OF THE FA
EXCEPT FOR SOME HIGH CIRRUS STREAMING DOWN INTO FAR NW COUNTIES
ATTM FROM THE NORTH.
FOR OVERNIGHT...THE COMBINATION OF AMPLE LOW LEVEL MOISTURE AND
CLEARING THIS EVENING WILL RESULT IN THE DEVELOPMENT OF LOW
STRATUS AFTER MIDNIGHT TONIGHT. ONCE AGAIN...S-SW WINDS AT OR
ABOVE 5 KT WILL PREVENT FOG FROM FORMING. HOWEVER IF ANY
OBSERVATION SITES REPORT VISIBILITIES LOWER THAN 7 STATUTE
MILES...THE OBSCURATION WILL LIKELY BE MORE HAZE THAN FOG/MIST
(VERY SIMILAR TO MONDAY NIGHT). TEMPS WILL REMAIN WELL ABOVE
NORMAL TONIGHT WITH LOWS IN THE MID TO UPPER 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
SIMILAR PATTERN AS LAST COUPLE DAYS WILL CONTINUE INTO WED. SW
FLOW ALOFT RESUMES AFTER A MID-LVL LO PUSHES OFFSHORE TNGT.
DEEP LAYER MOISTURE WILL THEN SLOWLY INCREASE WED INTO WED NGT
AHEAD OF A LO PRES SYSTM PASSING THRU THE GREAT LAKES REGION. DID
INCLUDE A SLGT CHC FOR A SHWR/TSTM WED AFTN/EVENG WITH A WARM AND
MOIST AIRMASS IN PLACE...HOWEVER MOST AREAS SHUD REMAIN DRY DUE TO
A LACK OF FORCING. OTW...EXPECT A PRTLY CLDY SKY WITH HIGHS IN THE
MID 80S.
FOR THU...COLD FRNT APPROACHES FROM THE OH VALLEY...AND RAIN
LIKELY WITH INCREASING MOISTURE AND S/W ENERGY ALOFT. UP TO A HALF
INCH OF PRECIP PSBL WITH THE BEST CHC FOR RAIN IN THE AFTN. HI
TEMPS GENRLY IN THE LO 80S. READINGS WILL BE A BIT COOLER NEAR
THE COAST. THE RAIN WILL END FROM WEST TO EAST THU NGT/FRI MRNG AS
THE COLD FRNT ADVANCES OFF THE COAST. NOT EXPECTING SKIES TO
COMPLETELY CLR OUT...WITH MOISTURE STILL IN PLACE ALOFT FOLLOWING
THE SFC FROPA.
DRIER CONDS EXPECTED BY FRI AFTN AS FLOW BECOMES NWLY FOR THE
FIRST TIME IN SEVERAL DAYS...AND TEMPS ONLY REACHING THE MID 70S
IN MOST LOCATIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI NIGHT. CLRG
& COOL WITH DECOUPLING WINDS INLAND. CSTL WNDS STAY MIXED DUE TO LOW
PRS SLOWLY PULLING AWAY TO THE NE. LOWS M-U40S FROM I95 ON W...
NEAR 50 INVOF CHES BAY AND L-M50S AT THE COAST.
SUNNY & PLEASANT SAT WITH H5 RIDGE OVRHD. HIGHS IN THE L-M70S XCPT
60S AT THE BEACHES. PT CLDY SAT NITE AS SOME HIGH LVL MSTR OVRSPRDS
RGN. LOWS 50-55. PT SUNNY AND A BIT WRMR SUN. HIGHS M-U70S XCPT
65-70 AT THE BEACHES.
TRICKY FCST ERLY NEXT WEEK. MODELS NOW INCRG MSTR DUE TO COMBO OF
ONSHORE E-SE FLOW AND WRM FRNT APPRCHG FROM THE SW. APPEARS BEST
SPRT FOR POPS WILL BE ACROSS SRN & WRN VA/NRN NC MONDAY & MON
NITE. KEPT SLGHT CHC POPS ON TUE FOR NOW GIVEN THE LOW CONFIDENCE
THIS FAR OUT. HIGHS MON L-M70S. LOWS 55-60. HIGHS TUE M-U70S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
SW WINDS WILL PREVAIL DURING THE TAF PERIOD. WIDELY SCT CONVECTION
WILL BE PSBL OVER SE PORTIONS THROUGH EARLY EVENING. INCLUDED TEMPO
GROUP FOR TSTMS AT ECG THROUGH 20Z. ALL OF THE SITES WERE VARYING
BETWEEN VFR AND MVFR AND THIS WILL BE THE TREND FOR AT LEAST THE
FIRST FEW HOURS OF THE TAF PERIOD AND LIKELY AGAIN LATE WEDNESDAY
MORNING. IFR STRATUS IS INDICATED BY MOS AND NAM BUFR SOUNDINGS AT
MOST OF THE TAF SITES FOR WEDNESDAY MORNING ROUGHLY FROM 08 TO 14Z.
CONDITIONS WILL SLOWLY IMPROVE WEDNESDAY MORNING.
OUTLOOK: ISOLATED TO WIDELY SCATTERED CONVECTION WILL BE PSBL LATE
WEDNESDAY AFTN AND EVENING. IFR STRATUS WILL BE PSBL AGAIN THURSDAY
MORNING. MORE WIDESPREAD CONVECTION IS EXPECTED THURSDAY AFTN AND
EVENING AS A COLD FRONT APPROACHES. THE WEATHER IMPROVES FRIDAY AND
BEYOND FOLLOWING THE COLD FRONTAL PASSAGE.
&&
.MARINE...
NO HEADLINES IN SHORT TERM AS WINDS REMAIN S-SW AOB 15KT THRU WED.
SOME CHANNELING UP THE BAY AS WELL AS SEAS APPRCHG 5 FT OUT NR 20 NM
INVOF BUOY 44009 BY WED NITE...BUT CONFIDENCE NOT HIGH ENUF TO GO
WITH A SUSTAINED SCA SO WILL HOLD OFF ON HEADLINES ATTM. SCA`S MAY
EVENTUALLY BE NEEDED FOR SEAS OVR NRN CSTL WTRS.
CDFRNT CROSSES THE WATERS LATE THU NITE FRI WITH LOW PRS MOVG N
ALONG IT. WILL HAVE TO MONITOR PRS GRDNT BTWN THIS LOW AND STRONG
HIGH PRS BLDG IN FROM THE NW FOR PSBL SCA CNDTNS FRI INTO FRI EVE.
OTW...HIGH PRS BUILDS INTO THE AREA OVER THE WEEKEND WITH SUB SCA
CNDTNS XPCTD BOTH SAT AND SUN.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD/MAS
NEAR TERM...BMD
SHORT TERM...MAS
LONG TERM...MPR
AVIATION...LSA
MARINE...MPR
[top]
000
FXUS61 KPBZ 212325
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
725 PM EDT TUE MAY 21 2013
.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MAINLY ACROSS
EASTERN OHIO THIS EVENING. INCREASING THUNDERSTORM CHANCES
WEDNESDAY AND THURSDAY AS A COLD FRONT APPROACHES AND MOVES
ACROSS THE REGION. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
ADJUSTED POPS DOWN A BIT AND REDUCED AREA OF CHANCE POPS THIS
EVENING TO EASTERN OHIO TOWARD I-79. APPEARS HI RES MODELS WERE
OVERDONE IN COMPLETELY BREAKING CAP ACROSS AREA...AND WHILE MUCAPE
IS OVER 2K MID LEVELS APPEAR A BIT WARM FOR DEEP CONVECTION.
STORMS HAVE PULSED ONLY FOR A TIME AND THEN WEAKEN. SCATTERED
STORMS WILL EVENTUALLY APPROACH PITTSBURGH METRO BUT LOOK TO BE
DYING AS THEY DO. ADJUSTED OVERNIGHT LOWS SLIGHTLY BASED ON DEW
POINT TRENDS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A VERY PRONOUNCED LOW LEVEL JET IS EVIDENT ON ALL GUIDANCE BY
WEDNESDAY MORNING NOSING INTO SOUTHWESTERN OHIO AHEAD OF AN
INCOMING UPPER LEVEL WAVE. GUIDANCE CONTINUES TO BE A BIT VARIED
ON ITS PLACEMENT AND EVOLUTION GOING INTO THE LATER MORNING
HOURS...HOWEVER ENOUGH GUIDANCE MEMBERS BRING IT INTO CENTRAL OHIO
BY LATE MORNING THAT THUNDERSTORMS MAY WELL DEVELOP ALONG THE NOSE
OF IT. IN CONJUNCTION...SEVERAL CONSECUTIVE NAM RUNS HAVE DEPICTED
A COMPACT SHORTWAVE EMBEDDED INTO THE SOUTHWESTERLY FLOW TO TRACK
OVER WESTERN AND CENTRAL OHIO FROM LATE MORNING THROUGH EARLY
AFTERNOON. AS THIS OCCURS...CONVECTION IS LIKELY TO BREAK OUT. IN
ADDITION...WITH CAPE VALUES AROUND 1500 J/KG AND STRONGER 0-6 KM
SHEAR LIKELY OVER OHIO THAN POINTS FARTHER EAST...BETTER CHANCES
OF THUNDERSTORM DEVELOPMENT EXIST IN OHIO THAN THE REST OF THE
FORECAST AREA THROUGH MOST OF THE DAYTIME ON WEDNESDAY. WITH
DECENT MID-LEVEL SUPPORT AND SHEAR/INSTABILITY...DAMAGING WINDS
WILL BE POSSIBLE WITH ANY MULTI-CELLULAR DEVELOPMENT THAT DOES
OCCUR FROM LATE MORNING ONWARD IN OHIO...WITH A LESSER CHANCE
FARTHER EAST.
AS THE UPPER LEVEL WAVE TRACKS FARTHER EAST WEDNESDAY
EVENING...THE RIGHT ENTRANCE REGION OF THE UPPER JET TRACKS
DIRECTLY OVER THE CWA. WITH IS IN CONCERT WITH THE MAIN SYNOPTIC
WAVE PASSAGE ROUGHLY 06Z/2AM THROUGH PITTSBURGH WEDNESDAY NIGHT.
BOTH NAM AND ECMWF SOLUTIONS ARE SUGGESTIVE OF LINEAR DEVELOPMENT
ALONG THE FRONTAL BOUNDARY AS IT PASSES THROUGH THE AREA LATE
WEDNESDAY EVENING/NIGHT...RESULTING IN THE POSSIBILITY OF A SQUALL
LINE MANAGING TO PERSIST WELL PAST THE NORMAL DIURNALLY FAVORED
HOURS OWING TO LARGE SCALE SUPPORT FOR ASCENT. CHANCES OF SEVERE
THUNDERSTORMS WITH DAMAGING WINDS WERE THUS ALLOWED TO SPREAD
ACROSS THE REST OF THE CWA FROM ROUGHLY 8 PM TO 3 AM AS THIS UPPER
WAVE PASSES THROUGH.
COLDER AIR FLOODS INTO THE AREA ON THURSDAY...HOWEVER WITH THE
MID-LEVELS COOLING MUCH QUICKER THAN THE LOW LEVELS...SHOWERS AND
THUNDERSTORMS WILL AGAIN BY POSSIBLE ACROSS THE AREA WITH SURFACE
TEMPERATURES MODERATING TOWARD 70F.
THE DUMP OF MUCH COLD AIR IS HELD BACK FOR A SECONDARY FRONTAL
PASSAGE ON FRIDAY WITH A WIDE SPREAD IN GUIDANCE FOR AFTERNOON
TEMPERATURES. ECMWF AND GFS 850 MB TEMPERATURES IN THE AFTERNOON
HOURS STRADDLE 0C...WHICH WOULD SUGGEST TEMPERATURES WOULD
STRUGGLE TO REACH 50F IF SUNSHINE FAILED TO MATERIALIZE. AT THE
MOMENT...IT WOULD SEEM MORE REASONABLE TO EXPECT AT LEAST SOME SUN
ON FRIDAY...SO HIGH TEMPERATURES WERE GENERALLY ADJUSTED FOR THE
MID 50S TO MID 60S ACROSS THE AREA. AS CONDITIONS CLEAR BY THE
AFTERNOON AND EVENING FRIDAY...COLD AIR ADVECTING INTO THE AREA
WILL LIKELY ALL FOR A VERY RAPID COOL OFF GOING INTO THE EVENING
AND POSSIBLY FROST BY THE OVERNIGHT. FRIES
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT ON THE OVERALL UPPER LEVEL PATTERN
THROUGH THE EXTENDED WITH AN UPPER LEVEL RIDGING OF THE CENTRAL
CONUS AND TROUGHING IN BOTH THE WEST AND EAST. WHILE THIS WOULD
GENERALLY LEAD TO A MUCH LESS THAN CONFIDENT FORECAST IN THE
SHORTWAVES WITHIN THE FLOW...THIS DOESN`T SEEM TO BE THE CASE AS
BOTH THE GFS AND ECMWF SUGGEST THAT MUCH OF THE PRECIPITATION WILL
BE SUPPRESSED SOUTH OF THE REGION THROUGH MUCH OF THE PERIOD.
THUS...OPTED TO TAKE A BLEND OF THE MODELS AND HPC
GUIDANCE. ALSO...HEDGED A BIT COOLER WITH TEMPERATURES WITH
NORTHWEST FLOW PRESENT ESPECIALLY FOR THE FIRST HALF OF THE
PERIOD. THIS KEPT TEMPERATURES BELOW SEASONAL AVERAGES SAT/SUN
BEFORE MODERATING CLOSER TO NORMAL FOR THE REST OF THE PERIOD.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
VFR CONDS EXPD INTO THE NGT. ISOLD TSTMS IN CNTRL OH...BUT UPR AND
MID LVL RIDGE AND CAPPING LIMITING ACTIVITY. WL MONITOR TSTMS BUT
NOT PLANNING ON INCLUDING IN TAFS ATTM. A PD OF MVFR VIS IN BR
EXPD TWD SUNRISE THEN VFR RETURNS THRU ERLY AFTN. SCT TSTMS EXP
LATER IN THE AFTN AS A CDFNT BEGINS TO APRCH SO INCLUDED VCTS.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
OCNL RESTRNS LIKELY WED EVE INTO THU NGT WITH SHWRS/TSTMS AS A
CDFNT APRCHS AND MOVES ACRS THE RGN. AN UPR LVL DISTURBANCE WL
BRING PSBL RESTRNS IN SHRA FRI BEFORE HIGH PRES AND VFR CONDS
RETURN FRI NGT THRU SUN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPHI 212208
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
608 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEASTERN UNITED STATES
COAST THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL MOVE FROM THE
SOUTHERN PLAINS TO SOUTHEASTERN CANADA THROUGH THURSDAY AND BRING
A COLD FRONT THROUGH THE REGION LATE THURSDAY INTO FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST FOR THE HOLIDAY WEEKEND
THIS HIGH WILL THEN GRADUALLY MOVE OFFSHORE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
ESTF UPDATE AT 550 PM.
STARTED THE EVENING MOSTLY CLEAR AND CUT OUT THE CHANCE OF SHOWERS
AND TSTMS PRIOR TO MIDNIGHT. THE ACTION IN MONROE AND SUSSEX
COUNTIES AROUND 2PM WAS ALL THAT WE WOULD HAVE TODAY.
THERE IS A SMALL CHANCE THAT ISOLATED CONVECTION NOW FORMING IN
FAR NORTH CENTRAL PA WILL TURN ESE AND INVADE THE POCONOS AROUND
11 PM BUT FOR NOW...MODEL SIGNALS ARE DRY FOR THIS EVENING AND
WITHOUT CU...ITS DIFFICULT TO HAVE A SHOWER.
THE FOG WAS DELAYED TIL LATER AND ATTM...NOT CALLING IT 1/4MI DENSE.
WILL REREVIEW FOG POTENTIAL LATER THIS EVENING.
LOW OVC WITH AREAS OF FOG SHOULD TEND TO BECOME WIDESPREAD AFTER
06Z. CONDITIONS WILL PROBABLY REMAIN ABOVE DENSE FOG ADVISORY
CRITERIA...SO WE HAVE NOT ISSUED. IT WILL REMAIN WARM AND HUMID
AGAIN TONIGHT WITH LOWS IN THE LOW/MID 60S NORTH AND MID/UPPER 60S
SOUTH. WINDS LIGHT MOSTLY FROM THE SW.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/...
WEDNESDAY WILL HAVE WEATHER SIMILAR TO TODAY. PLENTY OF CLOUDS/FOG IN
THE MORNING AND THE CHC FOR SHOWERS/TSTMS DURING THE AFTERNOON. THIS
ACTIVITY WILL PROBABLY BE FOUND ACROSS MOST AREAS...UNLIKE TDY WHERE
IT WAS RESTRICTED TO THE NORTH. WE WILL CARRY POPS IN THE CHC RANGE
FOR NOW. THE SPC HAS PLACED THE SLGT RISK FOR TSTMS TO THE WEST OF
OUR AREA...SO WE WILL WATCH FOR UPDATED OVERNIGHT. HIGHS WILL BE
VERY WARM AGAIN WED WITH TEMPS IN THE MID 80S IN MOST AREAS (EXCEPT
ALONG THE SHORE...WHERE READINGS IN THE UPPER 70S TO LOW 80S MAY
OCCUR).
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE AREA OF HIGH PRESSURE WILL REMAIN OFF THE ATLC CST WED NIGHT
AND THU AND SWLY FLOW WILL CONTINUE WHICH WILL KEEP WARM WX OVER
THE AREA. HOWEVER, BY THU, AN AREA OF LOW PRESSURE WILL MOVE INTO
SERN CANADA. THE CDFNT ASSOCD WITH THIS LOW WILL CROSS THE REGION
THU NIGHT. THIS PD LOOKS TO TO BE THE WETTEST WITH SHOWERS, TSTMS
AND PSBLY SOME HEAVY RAIN. ITS A BIT TOO EARLY TO BE CERTAIN ABOUT
ANY SEVER WX POTENTIAL. IT WILL BE DEPENDENT ON DAYTIME HEATING
AND OTHER FACTORS. HOWEVER, IT COULD BE MITIGATED BY THE FACT THAT
THE FRONT WILL BE COMING THROUGH AFTER SUNSET. THE 21/12Z GFS IS
THE SLOWEST MDL CLEARING THINGS OUT ON FRI AND TRIES TO DEVELOP A
WAVE ALG THE FRONT. NONE OF THE OTHER MDLS HAVE THIS FEATURE, SO
AM NOT INCLINED TO GO ALONG FOR NOW. FRI, ESPECIALLY LATER FRI,
SHOULD SEE IMPROVING WX AND BY SAT A LARGE AREA OF HIGH PRESSURE
WILL PUSH INTO THE MIDWEST FROM CANADA WAND WILL SLOWLY SLIDE EWD
THRU THE HOLIDAY WEEKEND.
THE PGRAD BETWEEN THE BUILDING HIGH AND THE DEPARTING LOW OVER THE
CANADIAN MARITIMES WILL KEEP A DECENT NWLY FLOW OVER THE AREA ON
SAT, WITH WEAKENING FLOW AS THE HIGH MOVES IN ON SUN. SO, AT THIS
POINT, THE WEEKEND LOOKS PREDOMINANTLY DRY, ALBEIT COOL FOR LATE
MAY AND WITH A BRISK NW WIND, IT WILL FEEL COOLER ON SAT.
TEMPS LOOK TO BE WARMEST ON THU, WITH TEMPS AROUND 80 OR INTO THE
80S. THEN BEHIND THE FRONT MOST LOCATIONS WILL BE AROUND 70 OR
INTO THE LOWER 70S FOR THE REMAINDER OF THE PD. SAT LOOKS TO BE
THE COOLEST DAYS, WITH MANY LOCATIONS HOVERING IN THE MID/UPPER 60S.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR CIRRUS WITH PATCHY SC VCNTY KACY-KMIV THIS EVENING.
LIGHT SSW WIND. CONDITIONS LIKELY TO BECOME IFR OR LIFR IN ST/FOG
AFTER 07Z.
WED...AFTER A PROBABLE IFR CONDITION START AT 12Z...A SLOW RETURN TO
VFR BY MID OR LATE MORNING WITH SCT-BKN CLOUDS AOA 3500 FT IN THE
AFTN AND A SHOWER OR TSTM POSSIBLE DURING THE AFTERNOON...MAINLY
VCNTY KRDG OR KABE. SW WIND GUST TO 15 KT IN THE AFTN.
OUTLOOK...
WED NIGHT THROUGH THU NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE IN ANY SHOWERS AND THUNDERSTORMS OR PDS OF
HEAVY RAIN. WIND WILL SHIFT FROM SW TO NW BEHIND CFP LATE WED
NIGHT/EARLY THU MRNG. HIGH CONFIDENCE ON THE OVERALL DETAILS. LOW
CONFIDENCE ON THE FACT THAT ALL SITES WILL SEE MVFR/IFR AND
TIMING.
FRI...MAINLY VFR WITH A CHANCE OF SHOWERS MAINLY IN THE MORNING.
HIGH CONFIDENCE.
SAT-SUN...VFR CONDITIONS EXPECTED. A BRISK NW WIND ON SAT OF 15-20
KT. HIGH CONFIDENCE.
&&
.MARINE...
WINDS HAVE BEEN MOSTLY SW/S ACROSS THE WATERS TODAY WITH SPEEDS
MOSTLY 10 TO 15 KTS. SEAS HAVE BEEN MOSTLY AROUND 3 FT ON THE OCEAN
AND 1 TO 2 FT OVER THE DEL BAY. CONDITIONS SHOULD REMAIN SUB-SCA
TONIGHT AND APPROACH SCA LATER WEDNESDAY. WINDS WILL INCREASE
WED...BUT WITH THE WARMER AIR AND COOLER SEAS...THE WINDS/WAVE
GUIDANCE MAY BE TOO HIGH. WE OPT TO KEEP THE SEAS AT 3 TO 4 FT FOR
WED AND HOLD THE WINDS BELOW SCA FLAG LEVELS. A FEW G 20-25 ARE NOT
OUT OF THE QUESTION LATER WED. SCAT SHOWERS/TSTMS EXPECTED WED.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WED NIGHT THROUGH
THU. AS THIS FLOW STRENGTHENS WITH A CDFNT APPROACHING FROM THE W
ON THU, WINDS AND SEAS WILL GRADUALLY INCREASE. THEREFORE, SEAS
AND WIND COULD BE AOA SCA CRITERIA BY THE START OF THE OUTLOOK PD. A
SMALL CRAFT ADVISORY MAY BE NEEDED FOR THIS PD ON THE OCEAN FRONT.
HOWEVER, WITH VERY WARM AIR OVER THE RELATIVELY COOL OCEAN AND
WAVE WATCH OVERDOING HEIGHTS OF LATE, HAVE DECIDED NOT TO POST
ANYTHING ATTM. THERE WILL ALSO BE SOME SHWRS/TSTMS WED NIGHT INTO
THU ALG AND AHEAD OF THE CFP.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SCA CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW CRITERIA THROUGH
THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...DRAG/O`HARA 607
SHORT TERM...DRAG/O`HARA
LONG TERM...NIERENBERG
AVIATION...DRAG/NIERENBERG/O`HARA 607
MARINE...DRAG/NIERENBERG/O`HARA 607
000
FXUS61 KLWX 212137
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
537 PM EDT TUE MAY 21 2013
.SYNOPSIS...
OFFSHORE HIGH PRESSURE WILL CONTINUE TO BRING WARM MOIST SOUTHERLY
AIR INTO THE REGION THROUGH THURSDAY. AFTERNOON AND EVENING
THUNDERSTORMS ARE POSSIBLE EACH DAY. A COLD FRONT WILL PASS
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. COOLER CONDITIONS
ARE EXPECTED OVER THE WEEKEND.
&&
.NEAR TERM /TONIGHT/...
ISOLD TSTMS PSBL OVR THE MTNS THRU MID EVE. THESE MAY PRODUCE
BRIEFLY HEAVY RAINS. UPR LVL WIND FIELD IS VERY LGT.
LGT FOG PSBL AFTR MDNGT...MOST PREVALENT RIGHT B4 SUNRISE AND THEN
QUICKLY BURNING OFF. LOWS IN THE 60S XCPT L70S IN THE CITIES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
CWFA WL BE WARM SECTOR THRU PD...AS SFC HIGH WELL OFF ERN SEABOARD
AIDS SLY FLOW/MOISTURE ADVECTION. THUS AMS WL REMAIN UNSTBL...W/
POPS GNLY INCREASING IN RESPONSE TO DROPPING MID LVL HGTS. WL STILL
HV A DIURNAL TREND TO STORMS. THU LOOKS TO BE THE BETTER DAY IN
TERMS OF TSRA DVLPMNT AS CDFNT/UPR LOW DROPS THRU GRTLKS. HV
RAISED POPS BOTH DAYS AND INTRODUCED LKLYS ON THU.
SPC HAS WRN MD/HIGHLANDS OUTLOOKED IN SLT RISK THU AHD OF THE CD
FNT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
CFP THU NGT. AFTR THAT THE NEXT SVRL DAYS LOOKING GOOD AS CANADIAN
HIGH PRESSURE BUILDS IN WITH TEMPS 5-10 DEGREES BELOW NORMAL.
SHORTWAVE OVER THE TN VLY ON SUNDAY SHOULD REMAIN WEST OF THE LWX
CWA...WILL HAVE TO MONITOR FOR INCREASED POPS. AS OF NOW EXPECT
SOME HIGH CLOUDS SUNDAY WITH A WARMING TREND STARTING THAT
CONTINUES INTO MID NEXT WEEK.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
VFR CONDS AT ALL TERMINALS. XPCT AREAS OF LOW CLOUDS/FOG TO DVLP
LT TNGT...CONTG INTO THE WED MRNG PUSH BUT DISSIPATING AFTR
SUNRISE. THIS TIME HV LEANED MORE TWD FOG DVLPMNT INLAND SINCE
SKIES WL BE PRTLY CLR SUPPORTING RADL COOLING DOWN TO MOIST
DEWPTS. HWVR LOW CLDS WL BE LURKING JUST E OF DCA/BWI.
DIURNAL THUNDERSTORM ACTIVITY WED/THUR WITH IFR CONDS POSSIBLE IN
THE HEAVIEST ONES. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY
FLOW WITH CLEAR CONDS SATURDAY. JUST SOME HIGH CLOUDS ON SUNDAY.
&&
.MARINE...
THE PRESSURE GRADIENT WILL STRENGTHEN OVER THE REGION WED AFTN AND
NGT AS LOPRES MOVES THRU THE GREAT LAKES AND HIPRES REMAINS PARKED
OVER THE WRN ATLANTIC. SLY RETURN FLOW WILL INCREASE ACCORDINGLY
BETWEEN BOTH SYSTEMS. A SCA GOES IN EFFECT WED AFTN FOR THE WATERS
THAT ARE MOST PRONE TO SLY CHANNELING IN THE MID CHSPK BAY AND
LWR/MID TIDAL POTOMAC RVR. SCA EXPANDS WED NGT TO INCLUDE ALL OF THE
MD CHSPK BAY AS A SLY NOCTURNAL JET DEVELOPS.
SLY FLOW WITH HIGH PRESSURE OFFSHORE AHEAD OF A COLD FRONT THAT
COMES THROUGH THURSDAY NIGHT. SLY CHANNELING TO 20 KT POSSIBLE WED
EVENING...AND THURSDAY. NWLY FLOW TO 20 KT POSSIBLE FRIDAY. LIGHT
AND VARIABLE FLOW THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
EXPECT POSITIVE TIDAL ANOMALIES TO DEVELOP DURING THE MIDWEEK AS SLY
FLOW STRENGTHENS. CBOFS GUIDANCE...WHICH HAS VERIFIED FAIRLY WELL OF
LATE...FCST WATER LEVELS TO STAY BELOW MINOR COASTAL FLOODING
THRESHOLDS THRU AT LEAST THU MRNG.
COLD FRONT MOVES THRU ERY FRI MRNG. WLY WINDS BEHIND THE FRONT
SHOULD ERASE ANY POSITIVE TIDAL ANOMALIES.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ530-531-539.
SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ532>534-536-537-540>543.
&&
$$
UPDATE...WOODY!
000
FXUS61 KPBZ 212124
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
524 PM EDT TUE MAY 21 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE INTO THE EVENING...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AN AREA OF MORE STABLE AIR IS CURRENTLY SHIFTING EASTWARD FROM
EASTERN OHIO INTO WESTERN PENNSYLVANIA...WHICH REPRESENTS THE
REMNANTS OF THE COOL DOME UNDER THIS MORNING`S CONVECTIVE DEBRIS
THAT COVERED EASTERN OHIO. WITH INSOLATION QUICKLY WORKING TO WARM
THIS COOL DOME...IT IS EXPECTED EVEN THIS AREA WILL DEVELOP
CUMULUS WITHIN THE NEXT FEW HOURS. BEHIND THIS AREA...A RATHER
UNDERSTATED LOW LEVEL MOISTURE CONVERGENCE AREA REPRESENTED BY A
DEWPOINT DISCONTINUITY WITH VALUES IN THE MID TO UPPER 50S BEHIND
IT AND MID 60S AHEAD OF THE AREA OF WIND CONVERGENCE. GIVEN CAPE
VALUES FROM LAPS GUIDANCE PUSHING 3000 J/KG ACROSS PORTIONS OF THE
CWA...THIS MAY JUST BE ENOUGH TO SPARK OFF A CLUSTER OF
THUNDERSTORMS ALONG THIS BOUNDARY AS IT EDGES EASTWARD THIS
EVENING. THE FORECAST WAS ADJUSTED FOR THIS IDEA...AND THE HRRR
CONCURS WITH ITS DEVELOPMENT CONSISTENTLY OVER THE PAST SEVERAL
HOURS OF RUNS.
TEMPERATURES OVERNIGHT WERE ALLOWED TO STAY UP IN THE MID TO UPPER
60S ACROSS MUCH OF THE AREA OWING TO STRONG LOW LEVEL MOISTURE AND
CONTINUOUS SOUTHWESTERLY FEED INTO THE AREA. THIS MEANS ANOTHER
WARM AND SOUPY NIGHT ACROSS THE REGION. FRIES
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A VERY PRONOUNCED LOW LEVEL JET IS EVIDENT ON ALL GUIDANCE BY
WEDNESDAY MORNING NOSING INTO SOUTHWESTERN OHIO AHEAD OF AN
INCOMING UPPER LEVEL WAVE. GUIDANCE CONTINUES TO BE A BIT VARIED
ON ITS PLACEMENT AND EVOLUTION GOING INTO THE LATER MORNING
HOURS...HOWEVER ENOUGH GUIDANCE MEMBERS BRING IT INTO CENTRAL OHIO
BY LATE MORNING THAT THUNDERSTORMS MAY WELL DEVELOP ALONG THE NOSE
OF IT. IN CONJUNCTION...SEVERAL CONSECUTIVE NAM RUNS HAVE DEPICTED
A COMPACT SHORTWAVE EMBEDDED INTO THE SOUTHWESTERLY FLOW TO TRACK
OVER WESTERN AND CENTRAL OHIO FROM LATE MORNING THROUGH EARLY
AFTERNOON. AS THIS OCCURS...CONVECTION IS LIKELY TO BREAK OUT. IN
ADDITION...WITH CAPE VALUES AROUND 1500 J/KG AND STRONGER 0-6 KM
SHEAR LIKELY OVER OHIO THAN POINTS FARTHER EAST...BETTER CHANCES
OF THUNDERSTORM DEVELOPMENT EXIST IN OHIO THAN THE REST OF THE
FORECAST AREA THROUGH MOST OF THE DAYTIME ON WEDNESDAY. WITH
DECENT MID-LEVEL SUPPORT AND SHEAR/INSTABILITY...DAMAGING WINDS
WILL BE POSSIBLE WITH ANY MULTI-CELLULAR DEVELOPMENT THAT DOES
OCCUR FROM LATE MORNING ONWARD IN OHIO...WITH A LESSER CHANCE
FARTHER EAST.
AS THE UPPER LEVEL WAVE TRACKS FARTHER EAST WEDNESDAY
EVENING...THE RIGHT ENTRANCE REGION OF THE UPPER JET TRACKS
DIRECTLY OVER THE CWA. WITH IS IN CONCERT WITH THE MAIN SYNOPTIC
WAVE PASSAGE ROUGHLY 06Z/2AM THROUGH PITTSBURGH WEDNESDAY NIGHT.
BOTH NAM AND ECMWF SOLUTIONS ARE SUGGESTIVE OF LINEAR DEVELOPMENT
ALONG THE FRONTAL BOUNDARY AS IT PASSES THROUGH THE AREA LATE
WEDNESDAY EVENING/NIGHT...RESULTING IN THE POSSIBILITY OF A SQUALL
LINE MANAGING TO PERSIST WELL PAST THE NORMAL DIURNALLY FAVORED
HOURS OWING TO LARGE SCALE SUPPORT FOR ASCENT. CHANCES OF SEVERE
THUNDERSTORMS WITH DAMAGING WINDS WERE THUS ALLOWED TO SPREAD
ACROSS THE REST OF THE CWA FROM ROUGHLY 8 PM TO 3 AM AS THIS UPPER
WAVE PASSES THROUGH.
COLDER AIR FLOODS INTO THE AREA ON THURSDAY...HOWEVER WITH THE
MID-LEVELS COOLING MUCH QUICKER THAN THE LOW LEVELS...SHOWERS AND
THUNDERSTORMS WILL AGAIN BY POSSIBLE ACROSS THE AREA WITH SURFACE
TEMPERATURES MODERATING TOWARD 70F.
THE DUMP OF MUCH COLD AIR IS HELD BACK FOR A SECONDARY FRONTAL
PASSAGE ON FRIDAY WITH A WIDE SPREAD IN GUIDANCE FOR AFTERNOON
TEMPERATURES. ECMWF AND GFS 850 MB TEMPERATURES IN THE AFTERNOON
HOURS STRADDLE 0C...WHICH WOULD SUGGEST TEMPERATURES WOULD
STRUGGLE TO REACH 50F IF SUNSHINE FAILED TO MATERIALIZE. AT THE
MOMENT...IT WOULD SEEM MORE REASONABLE TO EXPECT AT LEAST SOME SUN
ON FRIDAY...SO HIGH TEMPERATURES WERE GENERALLY ADJUSTED FOR THE
MID 50S TO MID 60S ACROSS THE AREA. AS CONDITIONS CLEAR BY THE
AFTERNOON AND EVENING FRIDAY...COLD AIR ADVECTING INTO THE AREA
WILL LIKELY ALL FOR A VERY RAPID COOL OFF GOING INTO THE EVENING
AND POSSIBLY FROST BY THE OVERNIGHT. FRIES
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT ON THE OVERALL UPPER LEVEL PATTERN
THROUGH THE EXTENDED WITH AN UPPER LEVEL RIDGING OF THE CENTRAL
CONUS AND TROUGHING IN BOTH THE WEST AND EAST. WHILE THIS WOULD
GENERALLY LEAD TO A MUCH LESS THAN CONFIDENT FORECAST IN THE
SHORTWAVES WITHIN THE FLOW...THIS DOESN`T SEEM TO BE THE CASE AS
BOTH THE GFS AND ECMWF SUGGEST THAT MUCH OF THE PRECIPITATION WILL
BE SUPPRESSED SOUTH OF THE REGION THROUGH MUCH OF THE PERIOD.
THUS...OPTED TO TAKE A BLEND OF THE MODELS AND HPC
GUIDANCE. ALSO...HEDGED A BIT COOLER WITH TEMPERATURES WITH
NORTHWEST FLOW PRESENT ESPECIALLY FOR THE FIRST HALF OF THE
PERIOD. THIS KEPT TEMPERATURES BELOW SEASONAL AVERAGES SAT/SUN
BEFORE MODERATING CLOSER TO NORMAL FOR THE REST OF THE PERIOD.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
VFR CONDS EXPD THRU THE EVE. ISOLD TSTMS TRYING TO FIRE IN CNTRL
OH...BUT UPR AND MID LVL RIDGE AND CAPPING SHOULD HELP TO LIMIT
ACTIVITY. REMOVED VCTS SINCE TSTM COVG EXPD TO BE LOW...BUT WL AMD
IF TSTMS APRCH A TERMINAL. A PD OF MVFR VIS IN BR EXPD TWD SUNRISE
THEN VFR RETURNS THRU ERLY AFTN.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
RESTRNS EXPD WED EVE INTO THU NGT WITH SHWRS/TSTMS AS A CDFNT
APRCHS AND MOVES ACRS THE RGN. AN UPR LVL DISTURBANCE WL BRING
PSBL RESTRNS IN SHRA FRI BEFORE HIGH PRES AND VFR CONDS RETURN FRI
NGT THRU SUN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 211947
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
347 PM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO THE REGION
THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE MID ATLANTIC
THURSDAY NIGHT. HIGH PRESSURE RETURNS TO THE AREA FRIDAY INTO THE
WEEKEND WITH DRIER CONDITIONS AND COOLER TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CHC FOR SHWRS AND TSTMS WILL REMAIN ESPECIALLY OVER SE AREAS THRU
ERLY THIS EVENG. MAIN THREAT WILL BE HEAVY RAIN WITH PWATS ~1.9"
AND WEAK STEERING FLOW ALOFT. NOT EXPECTING ANY SVR WX DUE TO MARGINAL
MID-LVL LAPSE RATES...VERY WEAK WIND SHEAR AND FORCING. WITH THE
LOSS OF DAYTIME HEATING AND MAIN MOISTURE AXIS PULLING
OFFSHORE...ANY SHWRS WILL SUBSIDE THRU THE EVENG HRS...LEAVING DRY
CONDS FOR THE OVRNGT HRS. TEMPS REMAIN WELL ABOVE NORMAL TNGT AS
SOUTHERLY FLOW PERSISTS...LOWS IN THE MID TO UPR 60S UNDER A PRTLY
CLDY SKY. PATCHY FOG IS POSSIBLE BUT MORE IN THE WAY OF LO STRATUS
IS EXPECTED.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
SIMILAR PATTERN AS LAST COUPLE DAYS WILL CONTINUE INTO WED. SW
FLOW ALOFT RESUMES AFTER A MID-LVL LO PUSHES OFFSHORE TNGT.
DEEP LAYER MOISTURE WILL THEN SLOWLY INCREASE WED INTO WED NGT
AHEAD OF A LO PRES SYSTM PASSING THRU THE GREAT LAKES REGION. DID
INCLUDE A SLGT CHC FOR A SHWR/TSTM WED AFTN/EVENG WITH A WARM AND
MOIST AIRMASS IN PLACE...HOWEVER MOST AREAS SHUD REMAIN DRY DUE TO
A LACK OF FORCING. OTW...EXPECT A PRTLY CLDY SKY WITH HIGHS IN THE
MID 80S.
FOR THU...COLD FRNT APPROACHES FROM THE OH VALLEY...AND RAIN
LIKELY WITH INCREASING MOISTURE AND S/W ENERGY ALOFT. UP TO A HALF
INCH OF PRECIP PSBL WITH THE BEST CHC FOR RAIN IN THE AFTN. HI
TEMPS GENRLY IN THE LO 80S. READINGS WILL BE A BIT COOLER NEAR
THE COAST. THE RAIN WILL END FROM WEST TO EAST THU NGT/FRI MRNG AS
THE COLD FRNT ADVANCES OFF THE COAST. NOT EXPECTING SKIES TO
COMPLETELY CLR OUT...WITH MOISTURE STILL IN PLACE ALOFT FOLLOWING
THE SFC FROPA.
DRIER CONDS EXPECTED BY FRI AFTN AS FLOW BECOMES NWRLY FOR THE
FIRST TIME IN SEVERAL DAYS...AND TEMPS ONLY REACHING THE MID 70S
IN MOST LOCATIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI NIGHT. CLRG
& COOL WITH DECOUPLING WINDS INLAND. CSTL WNDS STAY MIXED DUE TO LOW
PRS SLOWLY PULLING AWAY TO THE NE. LOWS M-U40S FROM I95 ON W...NR 50
IVOF CHES BAY AND L-M50S AT THE COAST.
SUNNY & PLEASANT SAT WITH H5 RIDGE OVRHD. HIGHS IN THE L-M70S XCPT
60S AT THE BEACHES. PT CLDY SAT NITE AS SOME HIGH LVL MSTR OVRSPRDS
RGN. LOWS 50-55. PT SUNNY AND A BIT WRMR SUN. HIGHS M-U70S XCPT
65-70 AT THE BEACHES.
TRICKY FCST ERLY NEXT WEEK. MODELS NOW INCRG MSTR DUE TO COMBO OF
ONSHORE E-SE FLOW AND WRM FRNT APPRCHG FROM THE SW. APPEARS BEST
SPRT FOR POPS WILL BE ACROSS SRN & WRN VA / NRN NC MONDAY & MON
NITE. KEPT SLGHT CHC POPS ON TUE FOR NOW GIVEN THE LOW CONFIDENCE
THIS FAR OUT. HIGHS MON L-M70S. LOWS 55-60. HIGHS TUE M-U70S.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
SW WINDS WILL PREVAIL DURING THE TAF PERIOD. WIDELY SCT CONVECTION
WILL BE PSBL OVER SE PORTIONS THROUGH EARLY EVENING. INCLUDED TEMPO
GROUP FOR TSTMS AT ECG THROUGH 20Z. ALL OF THE SITES WERE VARYING
BETWEEN VFR AND MVFR AND THIS WILL BE THE TREND FOR AT LEAST THE
FIRST FEW HOURS OF THE TAF PERIOD AND LIKELY AGAIN LATE WEDNESDAY
MORNING. IFR STRATUS IS INDICATED BY MOS AND NAM BUFR SOUNDINGS AT
MOST OF THE TAF SITES FOR WEDNESDAY MORNING ROUGHLY FROM 08 TO 14Z.
CONDITIONS WILL SLOWLY IMPROVE WEDNESDAY MORNING.
OUTLOOK: ISOLATED TO WIDELY SCATTERED CONVECTION WILL BE PSBL LATE
WEDNESDAY AFTN AND EVENING. IFR STRATUS WILL BE PSBL AGAIN THURSDAY
MORNING. MORE WIDESPREAD CONVECTION IS EXPECTED THURSDAY AFTN AND
EVENING AS A COLD FRONT APPROACHES. THE WEATHER IMPROVES FRIDAY AND
BEYOND FOLLOWING THE COLD FRONTAL PASSAGE.
&&
.MARINE...
NO HEADLINES IN SHORT TERM AS WINDS REMAIN S-SW AOB 15KT THRU WED.
SOME CHANNELING UP THE BAY AS WELL AS SEAS APPRCHG 5 FT OUT NR 20 NM
IVOF BUOY 44009 BY WED NITE...BUT CONFIDENCE NOT HIGH ENUF TO GO
WITH A SUSTAINED SCA SO WILL HOLD OFF ON HEADLINES ATTM. SCA`S MAY
EVENTUALLY BE NEEDED FOR SEAS OVR NRN CSTL WTRS.
CDFRNT CROSSES THE WATERS LATE THU NITE FRI WITH LOW PRS MOVG N
ALONG IT. WILL HAVE TO MONITOR PRS GRDNT BTWN THIS LOW AND STRONG
HIGH PRS BLDG IN FROM THE NW FOR PSBL SCA CNDTNS FRI INTO FRI EVE.
OTW...HIGH PRS BUILDS INTO THE AREA OVER THE WEEKEND WITH SUB SCA
CNDTNS XPCTD BOTH SAT AND SUN.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD/MAS
NEAR TERM...MAS
SHORT TERM...MAS
LONG TERM...MPR
AVIATION...LSA
MARINE...MPR
000
FXUS61 KPBZ 211938
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
338 PM EDT TUE MAY 21 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE INTO THE EVENING...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AN AREA OF MORE STABLE AIR IS CURRENTLY SHIFTING EASTWARD FROM
EASTERN OHIO INTO WESTERN PENNSYLVANIA...WHICH REPRESENTS THE
REMNANTS OF THE COOL DOME UNDER THIS MORNING`S CONVECTIVE DEBRIS
THAT COVERED EASTERN OHIO. WITH INSOLATION QUICKLY WORKING TO WARM
THIS COOL DOME...IT IS EXPECTED EVEN THIS AREA WILL DEVELOP
CUMULUS WITHIN THE NEXT FEW HOURS. BEHIND THIS AREA...A RATHER
UNDERSTATED LOW LEVEL MOISTURE CONVERGENCE AREA REPRESENTED BY A
DEWPOINT DISCONTINUITY WITH VALUES IN THE MID TO UPPER 50S BEHIND
IT AND MID 60S AHEAD OF THE AREA OF WIND CONVERGENCE. GIVEN CAPE
VALUES FROM LAPS GUIDANCE PUSHING 3000 J/KG ACROSS PORTIONS OF THE
CWA...THIS MAY JUST BE ENOUGH TO SPARK OFF A CLUSTER OF
THUNDERSTORMS ALONG THIS BOUNDARY AS IT EDGES EASTWARD THIS
EVENING. THE FORECAST WAS ADJUSTED FOR THIS IDEA...AND THE HRRR
CONCURS WITH ITS DEVELOPMENT CONSISTENTLY OVER THE PAST SEVERAL
HOURS OF RUNS.
TEMPERATURES OVERNIGHT WERE ALLOWED TO STAY UP IN THE MID TO UPPER
60S ACROSS MUCH OF THE AREA OWING TO STRONG LOW LEVEL MOISTURE AND
CONTINUOUS SOUTHWESTERLY FEED INTO THE AREA. THIS MEANS ANOTHER
WARM AND SOUPY NIGHT ACROSS THE REGION. FRIES
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A VERY PRONOUNCED LOW LEVEL JET IS EVIDENT ON ALL GUIDANCE BY
WEDNESDAY MORNING NOSING INTO SOUTHWESTERN OHIO AHEAD OF AN
INCOMING UPPER LEVEL WAVE. GUIDANCE CONTINUES TO BE A BIT VARIED
ON ITS PLACEMENT AND EVOLUTION GOING INTO THE LATER MORNING
HOURS...HOWEVER ENOUGH GUIDANCE MEMBERS BRING IT INTO CENTRAL OHIO
BY LATE MORNING THAT THUNDERSTORMS MAY WELL DEVELOP ALONG THE NOSE
OF IT. IN CONJUNCTION...SEVERAL CONSECUTIVE NAM RUNS HAVE DEPICTED
A COMPACT SHORTWAVE EMBEDDED INTO THE SOUTHWESTERLY FLOW TO TRACK
OVER WESTERN AND CENTRAL OHIO FROM LATE MORNING THROUGH EARLY
AFTERNOON. AS THIS OCCURS...CONVECTION IS LIKELY TO BREAK OUT. IN
ADDITION...WITH CAPE VALUES AROUND 1500 J/KG AND STRONGER 0-6 KM
SHEAR LIKELY OVER OHIO THAN POINTS FARTHER EAST...BETTER CHANCES
OF THUNDERSTORM DEVELOPMENT EXIST IN OHIO THAN THE REST OF THE
FORECAST AREA THROUGH MOST OF THE DAYTIME ON WEDNESDAY. WITH
DECENT MID-LEVEL SUPPORT AND SHEAR/INSTABILITY...DAMAGING WINDS
WILL BE POSSIBLE WITH ANY MULTI-CELLULAR DEVELOPMENT THAT DOES
OCCUR FROM LATE MORNING ONWARD IN OHIO...WITH A LESSER CHANCE
FARTHER EAST.
AS THE UPPER LEVEL WAVE TRACKS FARTHER EAST WEDNESDAY
EVENING...THE RIGHT ENTRANCE REGION OF THE UPPER JET TRACKS
DIRECTLY OVER THE CWA. WITH IS IN CONCERT WITH THE MAIN SYNOPTIC
WAVE PASSAGE ROUGHLY 06Z/2AM THROUGH PITTSBURGH WEDNESDAY NIGHT.
BOTH NAM AND ECMWF SOLUTIONS ARE SUGGESTIVE OF LINEAR DEVELOPMENT
ALONG THE FRONTAL BOUNDARY AS IT PASSES THROUGH THE AREA LATE
WEDNESDAY EVENING/NIGHT...RESULTING IN THE POSSIBILITY OF A SQUALL
LINE MANAGING TO PERSIST WELL PAST THE NORMAL DIURNALLY FAVORED
HOURS OWING TO LARGE SCALE SUPPORT FOR ASCENT. CHANCES OF SEVERE
THUNDERSTORMS WITH DAMAGING WINDS WERE THUS ALLOWED TO SPREAD
ACROSS THE REST OF THE CWA FROM ROUGHLY 8 PM TO 3 AM AS THIS UPPER
WAVE PASSES THROUGH.
COLDER AIR FLOODS INTO THE AREA ON THURSDAY...HOWEVER WITH THE
MID-LEVELS COOLING MUCH QUICKER THAN THE LOW LEVELS...SHOWERS AND
THUNDERSTORMS WILL AGAIN BY POSSIBLE ACROSS THE AREA WITH SURFACE
TEMPERATURES MODERATING TOWARD 70F.
THE DUMP OF MUCH COLD AIR IS HELD BACK FOR A SECONDARY FRONTAL
PASSAGE ON FRIDAY WITH A WIDE SPREAD IN GUIDANCE FOR AFTERNOON
TEMPERATURES. ECMWF AND GFS 850 MB TEMPERATURES IN THE AFTERNOON
HOURS STRADDLE 0C...WHICH WOULD SUGGEST TEMPERATURES WOULD
STRUGGLE TO REACH 50F IF SUNSHINE FAILED TO MATERIALIZE. AT THE
MOMENT...IT WOULD SEEM MORE REASONABLE TO EXPECT AT LEAST SOME SUN
ON FRIDAY...SO HIGH TEMPERATURES WERE GENERALLY ADJUSTED FOR THE
MID 50S TO MID 60S ACROSS THE AREA. AS CONDITIONS CLEAR BY THE
AFTERNOON AND EVENING FRIDAY...COLD AIR ADVECTING INTO THE AREA
WILL LIKELY ALL FOR A VERY RAPID COOL OFF GOING INTO THE EVENING
AND POSSIBLY FROST BY THE OVERNIGHT. FRIES
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT ON THE OVERALL UPPER LEVEL PATTERN
THROUGH THE EXTENDED WITH AN UPPER LEVEL RIDGING OF THE CENTRAL
CONUS AND TROUGHING IN BOTH THE WEST AND EAST. WHILE THIS WOULD
GENERALLY LEAD TO A MUCH LESS THAN CONFIDENT FORECAST IN THE
SHORTWAVES WITHIN THE FLOW...THIS DOESN`T SEEM TO BE THE CASE AS
BOTH THE GFS AND ECMWF SUGGEST THAT MUCH OF THE PRECIPITATION WILL
BE SUPPRESSED SOUTH OF THE REGION THROUGH MUCH OF THE PERIOD.
THUS...OPTED TO TAKE A BLEND OF THE MODELS AND HPC
GUIDANCE. ALSO...HEDGED A BIT COOLER WITH TEMPERATURES WITH
NORTHWEST FLOW PRESENT ESPECIALLY FOR THE FIRST HALF OF THE
PERIOD. THIS KEPT TEMPERATURES BELOW SEASONAL AVERAGES SAT/SUN
BEFORE MODERATING CLOSER TO NORMAL FOR THE REST OF THE PERIOD.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
GENERAL VFR IS EXPECTED THROUGH THE AFTERNOON. HOWEVER...SINCE WE
REMAIN IN THE WARM SECTOR...PLENTY OF INSTABILITY IS PRESENT FOR
THE DEVELOPMENT OF THUNDERSTORMS...WHICH IS PROGGED TO OCCUR
AROUND 21-23Z ACROSS THE REGION BASED ON HI RES MODEL OUTPUT.
CURRENT THINKING IS THAT A WEAK BOUNDARY...INDICATED BY A WIND
SHIFT OVER OH COULD BECOME THE FOCUS FOR DEVELOPMENT AS A WAVE
APPROACHES. SINCE THUNDERSTORMS HAVE YET TO DEVELOP AND CONFIDENCE
THAT ANY ONE SITE WILL BE IMPACTED REMAINING LOW...DECIDED TO
MAINTAIN THE VCTS MENTION FOR APPROX 4-5 HOURS THROUGH THE EARLY
EVENING. THERE COULD BE TEMPORARY RESTRICTIONS TO VISIBILITY IN
ANY SHOWERS THAT DO DEVELOP...BUT ALSO OPTED TO KEEP THIS OUT AT
THIS TIME.
OVERNIGHT FOG COULD ONCE AGAIN DEVELOP AS THE LOW LEVELS REMAIN
MOIST...ESPECIALLY IF ANY AREAS RECEIVE RAINFALL.
S-SW WIND WILL CONTINUE AT 5-10KTS TODAY AND OVERNIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND CROSSES THE REGION. NORTHWEST FLOW
MAY CONTINUE THE CHANCE FOR SHOWERS AND SOME RESTRICTIONS FRIDAY BEFORE
BUILDING HIGH PRESSURE BRINGS THE RETURN OF VFR FRIDAY NIGHT AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KLWX 211859
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
259 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE ATLANTIC WILL CONTINUE TO AID A SOUTHERLY
FLOW THROUGH THURSDAY...BRINGING WARM AND HUMID CONDITIONS.
AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE EACH DAY. A
COLD FRONT WILL PASS THROUGH THE REGION THURSDAY NIGHT INTO
FRIDAY. COOLER CONDITIONS ARE EXPECTED OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
H5 TROF HAS WEAKENED AND SLID SE OF CWFA. THAT LEAVES CWFA W/IN
SLY FLOW FM RDGG SFC-H5. AMS REMAINS UNSTBL BUT CAPPED...W/ SHEN
VLY/PTMC HIGHLANDS LKLY NEAREST CONVECTIVE TEMPS IN THE UPR 80S.
FORTUNATELY SEE NO SIGNS OF DVLPMNT THRU THE OHVLY...AND HV SCALED
POPS BACK BY ABT 10 PCT. AM STILL HOLDING ONTO CHC POPS SINCE WERE
CLOSE TO BREAKING CAP IN THE W...AND THERE/S PLENTY OF CAPE TO
FEED OFF OF ONCE WE DO. ANY ACTIVITY WL BE FAIRLY UNORGANIZED...
SINCE TRRN CURCULATIONS/DIFF HEATING BNDRYS WL BE BEST TRIGGERS.
ONCE DAYTIME HEATING WANES...RISK DIMINISHES...AND HV SCALED BACK
POPS FOR THE OVNGT HRS. DEWPTS HIGH ENUF THAT W/ PARTLY CLR SKIES
PATCHY FOG SHUD DVLP.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
CWFA WL BE WARM SECTOR THRU PD...AS SFC HIGH WELL OFF ERN SEABOARD
AIDS SLY FLOW/MOISTURE ADVECTION. THUS AMS WL REMAIN UNSTBL...W/
POPS GNLY INCREASING IN RESPONSE TO DROPPING MID LVL HGTS. WL STILL
HV A DIURNAL TREND TO STORMS. THU LOOKS TO BE THE BETTER DAY IN
TERMS OF TSRA DVLPMNT AS CDFNT/UPR LOW DROPS THRU GRTLKS. HV
RAISED POPS BOTH DAYS AND INTRODUCED LKLYS ON THU.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CFP THU NGT. CANADIAN HIGH PRESSURE BUILDS IN WITH TEMPS 5-10
DEGREES BELOW NORMAL. SHORTWAVE OVER THE TN VLY ON SUNDAY SHOULD
REMAIN WEST OF THE LWX CWA...WILL HAVE TO MONITOR FOR INCREASED
POPS. AS OF NOW EXPECT SOME HIGH CLOUDS SUNDAY WITH A WARMING
TREND STARTING THAT CONTINUES INTO MID NEXT WEEK.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
LOW-LEVEL MOISTURE HAS FINALLY SCOURED OUT...LEAVING VFR CONDS AT
ALL TERMINALS. ISOLD SHOWERS AND T-STORMS ARE STILL POSSIBLE THIS
AFTERNOON AND EVENING...PARTICULARLY FOR MRB/CHO...BUT THREAT WAY
TOO SLIM FOR TAF INCLUSION. XPCT AREAS OF LOW CLOUDS/FOG TO DVLP
AGN LT TNGT...CONTG INTO THE WED MRNG PUSH. THIS TIME HV LEANED
MORE TWD FOG DVLPMNT INLAND SINCE SKIES WL BE PRTLY CLR SUPPORTING
RADL COOLING DOWN TO MOIST DEWPTS. HWVR LOW CLDS WL BE LURKING
JUST E OF DCA/BWI.
DIURNAL THUNDERSTORM ACTIVITY WED/THUR WITH IFR CONDS POSSIBLE IN
THE HEAVIEST ONES. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY
FLOW WITH CLEAR CONDS SATURDAY. JUST SOME HIGH CLOUDS ON SUNDAY.
&&
.MARINE...
THE PRESSURE GRADIENT WILL STRENGTHEN OVER THE REGION WED AFTN AND
NGT AS LOPRES MOVES THRU THE GREAT LAKES AND HIPRES REMAINS PARKED
OVER THE WRN ATLANTIC. SLY RETURN FLOW WILL INCREASE ACCORDINGLY
BETWEEN BOTH SYSTEMS. A SCA GOES IN EFFECT WED AFTN FOR THE WATERS
THAT ARE MOST PRONE TO SLY CHANNELING IN THE MID CHSPK BAY AND
LWR/MID TIDAL POTOMAC RVR. SCA EXPANDS WED NGT TO INCLUDE ALL OF THE
MD CHSPK BAY AS A SLY NOCTURNAL JET DEVELOPS.
SLY FLOW WITH HIGH PRESSURE OFFSHORE AHEAD OF A COLD FRONT THAT
COMES THROUGH THURSDAY NIGHT. SLY CHANNELING TO 20 KT POSSIBLE WED
EVENING...AND THURSDAY. NWLY FLOW TO 20 KT POSSIBLE FRIDAY. LIGHT
AND VARIABLE FLOW THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
DESPITE SLY WINDS...WATER LEVELS THIS AFTN ARE NEAR ASTRONOMICAL
TIDE AND EVEN A FEW INCHES BELOW NORMAL IN THE TIDAL POTOMAC. DO
EXPECT POSITIVE TIDAL ANOMALIES TO DEVELOP DURING THE MIDWEEK AS SLY
FLOW STRENGTHENS. CBOFS GUIDANCE...WHICH HAS VERIFIED FAIRLY WELL OF
LATE...FCST WATER LEVELS TO STAY COMFORTABLY BELOW MINOR COASTAL
FLOODING THRESHOLDS THRU AT LEAST THU MRNG.
COLD FRONT MOVES THRU ERY FRI MRNG. WLY WINDS BEHIND THE FRONT
SHOULD ERASE ANY POSITIVE TIDAL ANOMALIES.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ530-531-539.
SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 6 AM EDT THURSDAY
FOR ANZ532>534-536-537-540>543.
&&
$$
000
FXUS61 KPHI 211855
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
255 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEASTERN UNITED STATES
COAST THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL MOVE FROM THE
SOUTHERN PLAINS TO SOUTHEASTERN CANADA THROUGH THURSDAY AND BRING
A COLD FRONT THROUGH THE REGION LATE THURSDAY INTO FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST FOR THE HOLIDAY WEEKEND
THIS HIGH WILL THEN GRADUALLY MOVE OFFSHORE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH 6 AM WEDNESDAY MORNING/...
ANY LINGERING SHOWERS/TSTMS ACROSS THE NORTHERN AREAS WILL DISSIPATE
THIS EVENING WITH THE LOSS OF HEATING. A FEW DOWNPOURS MAY OCCUR
WITH THE ACTIVITY EARLY. SKIES WILL BE PARTLY TO MOSTLY CLOUDY
EARLY...THEN TRANSITION BACK TO A LOW OVC ALONG WITH AREAS OF FOG
AGAIN TONIGHT. CONDITIONS WILL PROBABLY REMAIN ABOVE DENSE FOG
ADVISORY CRITERIA...SO WE HAVE NOT ISSUED THAT ATTM. IT WILL REMAIN
WARM AND HUMID AGAIN TONIGHT WITH LOWS IN THE LOW/MID 60S NORTH AND
MID/UPPER 60S SOUTH. WINDS LIGHT MOSTLY FROM THE SW.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY EVENING/...
WEDNESDAY WILL HAVE WEATHER SIMILAR TO TODAY. PLENTY OF CLOUDS/FOG IN
THE MORNING AND THE CHC FOR SHOWERS/TSTMS DURING THE AFTERNOON. THIS
ACTIVITY WILL PROBABLY BE FOUND ACROSS MOST AREAS...UNLIKE TDY WHERE
IT WAS RESTRICTED TO THE NORTH. WE WILL CARRY POPS IN THE CHC RANGE
FOR NOW. THE SPC HAS PLACED THE SLGT RISK FOR TSTMS TO THE WEST OF
OUR AREA...SO WE WILL WATCH FOR UPDATED OVERNIGHT. HIGHS WILL BE
VERY WARM AGAIN WED WITH TEMPS IN THE MID 80S IN MOST AREAS (EXCEPT
ALONG THE SHORE...WHERE READINGS IN THE UPPER 70S TO LOW 80S MAY
OCCUR).
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE AREA OF HIGH PRESSURE WILL REMAIN OFF THE ATLC CST WED NIGHT
AND THU AND SWLY FLOW WILL CONTINUE WHICH WILL KEEP WARM WX OVER
THE AREA. HOWEVER, BY THU, AN AREA OF LOW PRESSURE WILL MOVE INTO
SERN CANADA. THE CDFNT ASSOCD WITH THIS LOW WILL CROSS THE REGION
THU NIGHT. THIS PD LOOKS TO TO BE THE WETTEST WITH SHOWERS, TSTMS
AND PSBLY SOME HEAVY RAIN. ITS A BIT TOO EARLY TO BE CERTAIN ABOUT
ANY SEVER WX POTENTIAL. IT WILL BE DEPENDENT ON DAYTIME HEATING
AND OTHER FACTORS. HOWEVER, IT COULD BE MITIGATED BY THE FACT THAT
THE FRONT WILL BE COMING THROUGH AFTER SUNSET. THE 21/12Z GFS IS
THE SLOWEST MDL CLEARING THINGS OUT ON FRI AND TRIES TO DEVELOP A
WAVE ALG THE FRONT. NONE OF THE OTHER MDLS HAVE THIS FEATURE, SO
AM NOT INCLINED TO GO ALONG FOR NOW. FRI, ESPECIALLY LATER FRI,
SHOULD SEE IMPROVING WX AND BY SAT A LARGE AREA OF HIGH PRESSURE
WILL PUSH INTO THE MIDWEST FROM CANADA WAND WILL SLOWLY SLIDE EWD
THRU THE HOLIDAY WEEKEND.
THE PGRAD BETWEEN THE BUILDING HIGH AND THE DEPARTING LOW OVER THE
CANADIAN MARITIMES WILL KEEP A DECENT NWLY FLOW OVER THE AREA ON
SAT, WITH WEAKENING FLOW AS THE HIGH MOVES IN ON SUN. SO, AT THIS
POINT, THE WEEKEND LOOKS PREDOMINANTLY DRY, ALBEIT COOL FOR LATE
MAY AND WITH A BRISK NW WIND, IT WILL FEEL COOLER ON SAT.
TEMPS LOOK TO BE WARMEST ON THU, WITH TEMPS AROUND 80 OR INTO THE
80S. THEN BEHIND THE FRONT MOST LOCATIONS WILL BE AROUND 70 OR
INTO THE LOWER 70S FOR THE REMAINDER OF THE PD. SAT LOOKS TO BE
THE COOLEST DAYS, WITH MANY LOCATIONS HOVERING IN THE MID/UPPER 60S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
IT HAS BEEN TAKING A LONG TIME FOR THE PATCH OF ST ACROSS
MIV-PHL-ILG TO FINALLY DISSIPATE...BUT IT APPEARS THAT IT WILL BY
MID AFTERNOON. VFR CONDITIONS EXPECTED INTO THE EVENING...BEFORE A
RETURN BACK TO LOW MVFR/OR IFR CONDITIONS AGAIN TONIGHT. A FEW SCT
SHOWERS OR MAYBE A TSTM COULD AFFECT KABE LATER THIS AFTERNOON...BUT
THE PROB LOOKS TOO LOW TO INCLUDE IN THE TAFS ATTM. AMDS POSSIBLE.
WINDS SHOULD STAY MOSTLY SW INTO THE EVENING AND THEN GO MOSTLY
LIGHT S OVERNIGHT. WED...A SLOW RETURN TO VFR BY MID-MORNING THEN
SCT SHOWERS/TSTMS POSSIBLE DURING THE AFTERNOON.
OUTLOOK...
WED NIGHT THROUGH THU NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE IN ANY SHOWERS AND THUNDERSTORMS OR PDS OF
HEAVY RAIN. WIND WILL SHIFT FROM SW TO NW BEHIND CFP LATE WED
NIGHT/EARLY THU MRNG. HIGH CONFIDENCE ON THE OVERALL DETAILS. LOW
CONFIDENCE ON THE FACT THAT ALL SITES WILL SEE MVFR/IFR AND
TIMING.
FRI...MAINLY VFR WITH A CHANCE OF SHOWERS MAINLY IN THE MORNING.
HIGH CONFIDENCE.
SAT-SUN...VFR CONDITIONS EXPECTED. A BRISK NW WIND ON SAT OF 15-20
KT. HIGH CONFIDENCE.
&&
.MARINE...
WINDS HAVE BEEN MOSTLY SW/S ACROSS THE WATERS TODAY WITH SPEEDS
MOSTLY 10 TO 15 KTS. SEAS HAVE BEEN MOSTLY AROUND 3 FT ON THE OCEAN
AND 1 TO 2 FT OVER THE DEL BAY. CONDITIONS SHOULD REMAIN SUB-SCA
TONIGHT AND APPROACH SCA LATER WEDNESDAY. WINDS WILL INCREASE
WED...BUT WITH THE WARMER AIR AND COOLER SEAS...THE WINDS/WAVE
GUIDANCE MAY BE TOO HIGH. WE OPT TO KEEP THE SEAS AT 3 TO 4 FT FOR
WED AND HOLD THE WINDS BELOW SCA FLAG LEVELS. A FEW G 20-25 ARE NOT
OUT OF THE QUESTION LATER WED. SCAT SHOWERS/TSTMS EXPECTED WED.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WED NIGHT THROUGH
THU. AS THIS FLOW STRENGTHENS WITH A CDFNT APPROACHING FROM THE W
ON THU, WINDS AND SEAS WILL GRADUALLY INCREASE. THEREFORE, SEAS
AND WIND COULD BE AOA SCA CRITERIA BY THE START OF THE OUTLOOK PD. A
SMALL CRAFT ADVISORY MAY BE NEEDED FOR THIS PD ON THE OCEAN FRONT.
HOWEVER, WITH VERY WARM AIR OVER THE RELATIVELY COOL OCEAN AND
WAVE WATCH OVERDOING HEIGHTS OF LATE, HAVE DECIDED NOT TO POST
ANYTHING ATTM. THERE WILL ALSO BE SOME SHWRS/TSTMS WED NIGHT INTO
THU ALG AND AHEAD OF THE CFP.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SCA CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW CRITERIA THROUGH
THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
000
FXUS61 KPBZ 211854
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
254 PM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATE MORNING TRENDS ARE INDICATING DRAMATIC TEMPERATURE RISES
ACROSS WESTERN PENNSYLVANIA IN PARTICULAR. NEW CASTLE WAS ALREADY
83F AT 11 AM...WITH NEAR 80F COMMON ACROSS THE PITTSBURGH AREA.
TEMPERATURES WERE NUDGED UPWARD FOR THIS AFTERNOON IN THE
AFOREMENTIONED AREA...AND MAINTAINED ELSEWHERE.
PREVIOUS DISCUSSION FOLLOWS...CONVECTIVE DEBRIS CLOUDS ARE
CURRENTLY IN TRANSIT ACROSS THE FORECAST AREA AND CONCURRENTLY
DISSIPATING. TEMPERATURE READINGS ARE SEVERAL DEGREES HIGHER THAN
THIS TIME YESTERDAY AS WELL. WITH LITTLE IN THE WAY TO PREVENT
ABUNDANT INSOLATION ACROSS MUCH OF THE AREA...AND THE FACT THAT
THE LOW LEVEL THERMAL TONGUE WILL BE TRAVERSING THE HEART OF THE
CWA AT MAX HEATING...WITH 850 MB TEMPERATURES NEARING +18C AROUND
21Z OVER PITTSBURGH WITH DECENT BOUNDARY LAYER MIXING...IT WOULD
SEEM TEMPERATURES SHOULD SURPASS THOSE REACHED YESTERDAY. AS
SUCH...HIGHS WERE INCREASED INTO THE UPPER 80S FOR THE SOUTHERN
TWO-THIRDS OF THE CWA...AND THE MID 80S UP ALONG I-80.
WITH INCREASED HEATING AND SIMILAR DEWPOINTS AS COMPARED TO
YESTERDAY IN THE UPPER 60S...CAPE VALUES LOOK TO RUN UP TOWARD
3000 J/KG. GIVEN A WEAKLY SHEARED ENVIRONMENT AND NO SIGNIFICANT
SYNOPTIC OR MESOSCALE DISTURBANCE TO HARNESS THE CAPE...WIDESPREAD
THUNDERSTORM DEVELOPMENT IS NOT ANTICIPATED. HOWEVER...WEAK LOCAL
FORCING SEEMS LIKELY TO ALLOW FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ACROSS MUCH OF THE AREA BY
AFTERNOON...PARTICULARLY IN AREAS WEST OF PITTSBURGH AS WELL AS IN
THE RIDGES. POPS WERE INCREASED IN THESE AREAS. WITH WEAK SHEAR
AND WEAK MOMENTUM IN THE COLUMN...AS WELL AS A RATHER WARM
PROFILE...UPDRAFTS TO SUSTAIN HAIL DEVELOPMENT WILL BE DIFFICULT
TO MAINTAIN...HOWEVER A WIND GUST OR TWO MAY BE POSSIBLE OUT OF A
FEW OF THE CELLS. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVER CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION AND SHEAR VALUES
INCREASE. HAVE DECIDED TO GO WITH LIKELY POPS WED DUE TO THE
AFOREMENTIONED FACTORS. SPC CONTINUES TO KEEP THE AREA IN A SLIGHT
RISK FOR WED...SO WILL INCLUDE WORDING OF POSSIBLE SEVERE AND
MENTION IN HWO.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY...SO WILL
CONTINUE WITH LIKELY POPS. THURSDAYS NOT NEARLY AS UNSTABLE AS
TODAY OR WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL IN
QUESTION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THE MODELS ARE IN GOOD AGREEMENT ON THE OVERALL UPPER LEVEL PATTERN
THROUGH THE EXTENDED WITH AN UPPER LEVEL RIDGING OF THE CENTRAL
CONUS AND TROUGHING IN BOTH THE WEST AND EAST. WHILE THIS WOULD
GENERALLY LEAD TO A MUCH LESS THAN CONFIDENT FORECAST IN THE
SHORTWAVES WITHIN THE FLOW...THIS DOESN`T SEEM TO BE THE CASE AS
BOTH THE GFS AND ECMWF SUGGEST THAT MUCH OF THE PRECIPITATION WILL
BE SUPPRESSED SOUTH OF THE REGION THROUGH MUCH OF THE PERIOD.
THUS...OPTED TO TAKE A BLEND OF THE MODELS AND HPC
GUIDANCE. ALSO...HEDGED A BIT COOLER WITH TEMPERATURES WITH
NORTHWEST FLOW PRESENT ESPECIALLY FOR THE FIRST HALF OF THE
PERIOD. THIS KEPT TEMPERATURES BELOE SEASONAL AVERAGES SAT/SUN
BEFORE MODERATING CLOSER TO NORMAL FOR THE REST OF THE PERIOD.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
GENERAL VFR IS EXPECTED THROUGH THE AFTERNOON. HOWEVER...SINCE WE
REMAIN IN THE WARM SECTOR...PLENTY OF INSTABILITY IS PRESENT FOR
THE DEVELOPMENT OF THUNDERSTORMS...WHICH IS PROGGED TO OCCUR
AROUND 21-23Z ACROSS THE REGION BASED ON HI RES MODEL OUTPUT.
CURRENT THINKING IS THAT A WEAK BOUNDARY...INDICATED BY A WIND
SHIFT OVER OH COULD BECOME THE FOCUS FOR DEVELOPMENT AS A WAVE
APPROACHES. SINCE THUNDERSTORMS HAVE YET TO DEVELOP AND CONFIDENCE
THAT ANY ONE SITE WILL BE IMPACTED REMAINING LOW...DECIDED TO
MAINTAIN THE VCTS MENTION FOR APPROX 4-5 HOURS THROUGH THE EARLY
EVENING. THERE COULD BE TEMPORARY RESTRICTIONS TO VISIBILITY IN
ANY SHOWERS THAT DO DEVELOP...BUT ALSO OPTED TO KEEP THIS OUT AT
THIS TIME.
OVERNIGHT FOG COULD ONCE AGAIN DEVELOP AS THE LOW LEVELS REMAIN
MOIST...ESPECIALLY IF ANY AREAS RECEIVE RAINFALL.
S-SW WIND WILL CONTINUE AT 5-10KTS TODAY AND OVERNIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND CROSSES THE REGION. NORTHWEST FLOW
MAY CONTINUE THE CHANCE FOR SHOWERS AND SOME RESTRICTIONS FRIDAY BEFORE
BUILDING HIGH PRESSURE BRINGS THE RETURN OF VFR FRIDAY NIGHT AND
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 211812
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
212 PM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO THE AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND
COOLER TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THERE IS PLENTY OF LOW LEVEL MOISTURE(PWATS ~1.5 IN) AND MODERATE
CAPE VALUES(~1100 J/KG)...SO GENERALLY HAVE 30 TO 40 PERCENT POPS
ON TODAY DURING THE AFTERNOON AND EARLY EVENING HOURS...DECREASING
FOR THE LATE NIGHT AND MORNING HOURS.
TEMPERATURE WILL MAX OUT NEAR 80 ALONG THE COAST TO THE MID 80S
INLAND. HIGH TEMPS MAY END UP BEING A FEW DEGREES COOLER IF CLOUD
AND PRECIPITATION REGIONS ARE MORE EXPANSIVE THAN ANTICIPATED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THERE WILL BE LESS COVERAGE OF PRECIPITATION AS
UPPER LEVEL SUPPORT WEAKENS. GUIDANCE ON WEDNESDAY IS STILL
UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND KEPT 30 PERCENT
POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SW WINDS WILL PREVAIL DURING THE TAF PERIOD. WIDELY SCT CONVECTION
WILL BE PSBL OVER SE PORTIONS THROUGH EARLY EVENING. INCLUDED TEMPO
GROUP FOR TSTMS AT ECG THROUGH 20Z. ALL OF THE SITES WERE VARYING
BETWEEN VFR AND MVFR AND THIS WILL BE THE TREND FOR AT LEAST THE
FIRST FEW HOURS OF THE TAF PERIOD AND LIKELY AGAIN LATE WEDNESDAY
MORNING. IFR STRATUS IS INDICATED BY MOS AND NAM BUFR SOUNDINGS AT
MOST OF THE TAF SITES FOR WEDNESDAY MORNING ROUGHLY FROM 08 TO 14Z.
CONDITIONS WILL SLOWLY IMPROVE WEDNESDAY MORNING.
OUTLOOK: ISOLATED TO WIDELY SCATTERED CONVECTION WILL BE PSBL LATE
WEDNESDAY AFTN AND EVENING. IFR STRATUS WILL BE PSBL AGAIN THURSDAY
MORNING. MORE WIDESPREAD CONVECTION IS EXPECTED THURSDAY AFTN AND
EVENING AS A COLD FRONT APPROACHES. THE WEATHER IMPROVES FRIDAY AND
BEYOND FOLLOWING THE COLD FRONTAL PASSAGE.
&&
.MARINE...
NO FLAGS EXPECTED TODAY THRU WED...AS SSW FLO (AOB 15-20 KTS WITH
SEAS 2-4 FT) CONTINUES ARND HI PRES OFF THE CST. PRES GRADIENT
WILL INCREASE A BIT LATE WED THRU THU AHEAD OF APPROACHING COLD FRNT
PROGGED TO CROSS THE AREA THU NGT THRU FRI MORNG. ANY SCA CONDITIONS
THAT DEVELOP WILL BE MARGINAL AHEAD OF THE FRNT. WNA CONTINUES TO
FCST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED...BUT WILL
HOLD OFF ON ANY HEADLINE FOR NOW. WINDS WILL SHIFT TO THE NW OR N FRI
AFTN BEHIND THE FRNT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/MAS/DAP
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...LSA
MARINE...TMG
000
FXUS61 KPBZ 211534
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1134 AM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATE MORNING TRENDS ARE INDICATING DRAMATIC TEMPERATURE RISES
ACROSS WESTERN PENNSYLVANIA IN PARTICULAR. NEW CASTLE WAS ALREADY
83F AT 11 AM...WITH NEAR 80F COMMON ACROSS THE PITTSBURGH AREA.
TEMPERATURES WERE NUDGED UPWARD FOR THIS AFTERNOON IN THE
AFOREMENTIONED AREA...AND MAINTAINED ELSEWHERE.
PREVIOUS DISCUSSION FOLLOWS...CONVECTIVE DEBRIS CLOUDS ARE
CURRENTLY IN TRANSIT ACROSS THE FORECAST AREA AND CONCURRENTLY
DISSIPATING. TEMPERATURE READINGS ARE SEVERAL DEGREES HIGHER THAN
THIS TIME YESTERDAY AS WELL. WITH LITTLE IN THE WAY TO PREVENT
ABUNDANT INSOLATION ACROSS MUCH OF THE AREA...AND THE FACT THAT
THE LOW LEVEL THERMAL TONGUE WILL BE TRAVERSING THE HEART OF THE
CWA AT MAX HEATING...WITH 850 MB TEMPERATURES NEARING +18C AROUND
21Z OVER PITTSBURGH WITH DECENT BOUNDARY LAYER MIXING...IT WOULD
SEEM TEMPERATURES SHOULD SURPASS THOSE REACHED YESTERDAY. AS
SUCH...HIGHS WERE INCREASED INTO THE UPPER 80S FOR THE SOUTHERN
TWO-THIRDS OF THE CWA...AND THE MID 80S UP ALONG I-80.
WITH INCREASED HEATING AND SIMILAR DEWPOINTS AS COMPARED TO
YESTERDAY IN THE UPPER 60S...CAPE VALUES LOOK TO RUN UP TOWARD
3000 J/KG. GIVEN A WEAKLY SHEARED ENVIRONMENT AND NO SIGNIFICANT
SYNOPTIC OR MESOSCALE DISTURBANCE TO HARNESS THE CAPE...WIDESPREAD
THUNDERSTORM DEVELOPMENT IS NOT ANTICIPATED. HOWEVER...WEAK LOCAL
FORCING SEEMS LIKELY TO ALLOW FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ACROSS MUCH OF THE AREA BY
AFTERNOON...PARTICULARLY IN AREAS WEST OF PITTSBURGH AS WELL AS IN
THE RIDGES. POPS WERE INCREASED IN THESE AREAS. WITH WEAK SHEAR
AND WEAK MOMENTUM IN THE COLUMN...AS WELL AS A RATHER WARM
PROFILE...UPDRAFTS TO SUSTAIN HAIL DEVELOPMENT WILL BE DIFFICULT
TO MAINTAIN...HOWEVER A WIND GUST OR TWO MAY BE POSSIBLE OUT OF A
FEW OF THE CELLS. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVER CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION AND SHEAR VALUES
INCREASE. HAVE DECIDED TO GO WITH LIKELY POPS WED DUE TO THE
AFOREMENTIONED FACTORS. SPC CONTINUES TO KEEP THE AREA IN A SLIGHT
RISK FOR WED...SO WILL INCLUDE WORDING OF POSSIBLE SEVERE AND
MENTION IN HWO.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY...SO WILL
CONTINUE WITH LIKELY POPS. THURSDAYS NOT NEARLY AS UNSTABLE AS
TODAY OR WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL IN
QUESTION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FRONT WILL CLEAR THE AREA THU NIGHT AS A SHORTWAVE TROUGH SWINGS
THROUGH ON ITS HEELS. THIS WILL KEEP IN THE CHANCE FOR SHOWERS
THURSDAY NIGHT INTO EARLY FRIDAY. BEHIND THE COLD FRONT FRIDAY
TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED
FOR THE SECOND HALF OF FRIDAY INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY AND SUNDAY
MORNING.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS SHOULD PREVAIL FOR MUCH OF THE DAY. HOWEVER SINCE
WE REMAIN IN THE WARM SECTOR...PLENTY OF INSTABILITY WILL BE
PRESENT FOR THE DEVELOPMENT OF SOME THUNDERSTORMS ESPECIALLY IF WE
REACH CONVECTIVE TEMPERATURES TODAY...ALTHOUGH COVERAGE REMAINS IN
QUESTION. FOR NOW...WITH CONFIDENCE THAT ANY ONE THUNDERSTORM WILL
IMPACT A TAF SITE REMAINING LOW...CONTINUED VCTS MENTION. THERE
COULD BE TEMPORARY RESTRICTIONS TO VISIBILITY IN ANY SHOWERS THAT
DO DEVELOP...BUT ALSO OPTED TO KEEP THIS OUT AT THIS TIME.
OVERNIGHT FOG COULD ONCE AGAIN DEVELOP AS THE LOW LEVELS REMAIN
MOIST.
S-SW WIND WILL CONTINUE AT 5-10KTS TODAY AND OVERNIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND CROSSES THE REGION. BUILDING HIGH
PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPHI 211525
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1125 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED JUST OFF THE SOUTHEASTERN UNITED
STATES COAST THROUGH THURSDAY. LOW PRESSURE WILL APPROACH FROM THE
WEST, PASSING TO OUR NORTH, AND WILL DRAG A COLD FRONT THROUGH THE
REGION LATE THURSDAY INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD IN
FROM THE WEST FOR THE WEEKEND BEFORE MOVING OFFSHORE LATER SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
VARIOUS ADJUSTMENTS FOR THE ESTF WITH CLOUDS STUBBORN ACROSS THE
DELMARVA AND LOWER DEL VALLEY WITH SUNSHINE MUCH MORE ABUNDANT
ACROSS THE LEHIGH VALLEY AND THE NRN HALF OF NJ. TEMP TRENDS HAVE
BEEN ADJUSTED ACCORDINGLY WITH HIGHER READINGS NORTH/WEST AND
SLOWER RISES SOUTH/EAST. THERE IS A CHC FOR SHOWERS/TSTMS THIS
AFTERNOON...ESPECIALLY NORTH/WEST WITH BETTER INSTABILITY AND A
WEAKER CAP EXPECTED. UPDATED PUBLIC PRODUCTS WILL BE SENT SHORTLY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SYNOPTIC SITUATION OVERNIGHT DOES NOT CHANGE MUCH FROM THE
DAYTIME. A STRONGER SHORT WAVE/VORT MAX ALOFT IS FORECAST TO
APPROACH THE AREA OVERNIGHT, AT THE SAME TIME A WEAK SURFACE TROUGH
MAY MOVE ACROSS THE AREA. THERE COULD STILL BE SOME INSTABILITY
OVERNIGHT, WHICH COULD LEAD TO THE CHANCE FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA. WE LEFT FOG OUT OF THE
FORECAST OVERNIGHT AS THERE MAY BE ENOUGH MIXING TO PREVENT MUCH OF
THE DENSER FOG FROM DEVELOPING. A BLEND OF THE MAV/MET MOS WAS TAKEN
FOR OVERNIGHT LOWS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE DOMINATES OUR WEATHER OVER THE NEXT SEVERAL DAYS AS IT
SETS UP SHOP OVER THE SOUTHWESTERN ATLANTIC. WITH THE HIGH TO OUR
SOUTHEAST, WE WILL SEE A SOUTHWESTERLY FLOW CONTINUE ACROSS THE
REGION. THIS SOUTHWEST FLOW WILL ADVECT WARM AND MOIST AIR TO OUR
AREA AND WE WILL REMAIN ABOVE NORMAL FOR TEMPERATURES THROUGH AT
LEAST MID WEEK. WITH ALL THAT MOIST, WARM AIR, WE WILL ALSO START TO
DESTABILIZE. THIS WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH THE WEEK, MAINLY IN THE AFTERNOON AFTER
SUFFICIENT DAYTIME HEATING HAS OCCURRED AND CONVECTIVE TEMPERATURES
HAVE BEEN REACHED.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST ON THURSDAY, WITH
THE CENTER PASSING OFF TO OUR NORTH. THE ATTACHED COLD FRONT IS
FORECAST TO MOVE THROUGH OUR AREA THURSDAY INTO FRIDAY, MOST LIKELY
LATER IN THE DAY THURSDAY INTO EARLY FRIDAY. THE LATEST MODEL
GUIDANCE HAS SLOWED DOWN THE FRONTAL PASSAGE AND WITH LITTLE SUPPORT
OVERALL, WE HAVE OPTED TO KEEP THE FORECAST LARGELY THE SAME AND
LEAN A BIT MORE ON THE PROGRESSIVE SIDE.
THE FRONT PUSHES THROUGH AND OFFSHORE BY FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT, BRINGING IN SOME COOLER AND
DRIER AIR FOR THE HOLIDAY WEEKEND. THE MODELS HINT AT A
SHORTWAVE MOVING THROUGH THE MID LEVELS LATE SATURDAY OR SUNDAY WITH
A LIGHT SHOWER POSSIBLE. THE AIR LOOKS LIKE IT MIGHT BE TOO DRY FOR
ANYTHING TO MAKE IT TO THE SURFACE AND WE HAVE KEPT THE HOLIDAY
WEEKEND POP FREE.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CIGS/VSBYS ARE NOW DEVELOPING ACROSS THE TAF SITES. THE LOW
CLOUDS/FOG WILL BURN OFF THROUGH THE MID MORNING HOURS, AND
CONDITIONS WILL EVENTUALLY BECOME VFR. THERE IS A CHANCE FOR SOME
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON, BUT
CONFIDENCE IN THEM HITTING A PARTICULAR TAF SITE IS LOW, SO THEY
WERE LEFT OUT OF THE FORECAST FOR THE TIME BEING.
ANOTHER ROUND OF LOW CLOUDS/FOG IS POSSIBLE AGAIN TUESDAY NIGHT.
HOWEVER, THERE IS ALSO THE POSSIBILITY FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS OVERNIGHT AS WELL. CONFIDENCE IN THE SHOWERS
OCCURRING IS STILL LOW, SO THEY WERE LEFT OUT FOR NOW. ALSO, WITH
THE POTENTIAL FOR SOME MIXING TO OCCUR, SO WE DID NOT HIT THE LOW
CONDITIONS HARD JUST YET...WE`LL SEE HOW LATER GUIDANCE HANDLES THE
OVERNIGHT PERIOD.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE DURING THE EARLY MORNING HOURS. ALSO, SCATTERED
SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON AND EVENING,
MAY REDUCE CEILINGS AND VISIBILITIES AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW ADVISORY LEVELS THROUGH
TODAY INTO TONIGHT. HOWEVER, WINDS COULD PERIODICALLY GUST AROUND 20
KNOTS, ESPECIALLY LATER TODAY INTO TONIGHT. ALSO, SEAS WILL REMAIN
NEAR 4 FEET THROUGH THE PERIOD, AND MAY GET CLOSE TO 5 FEET
OVERNIGHT. CONFIDENCE IN CONDITIONS GETTING CLOSE TO ADVISORY LEVELS
IS NOT HIGH ENOUGH TO ISSUE AN ADVISORY.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WEDNESDAY THROUGH
THURSDAY. AS THIS FLOW STRENGTHENS, WINDS AND SEAS WILL GRADUALLY
INCREASE. SEAS WILL START TO RISE TO NEAR 5 FEET BY WEDNESDAY
AFTERNOON WITH WINDS STARTING TO GUST IN ADVANCE OF AN APPROACHING
COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE WEDNESDAY
AND THURSDAY ON THE OCEAN FRONT.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SMALL CRAFT ADVISORY CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW
CRITERIA THROUGH THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS
THE REGION.
WITH SUCH A WARM, MOIST AIRMASS IN PLACE THROUGH THURSDAY, THERE
WILL REMAIN A CHANCE FOR SOME PATCHY DENSE FOG TO FORM OVER THE AREA
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...O`HARA
SHORT TERM...ROBERTSON
LONG TERM...MEOLA
AVIATION...ROBERTSON/MEOLA
MARINE...ROBERTSON/MEOLA
000
FXUS61 KAKQ 211451
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1051 AM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO THE AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND
COOLER TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THERE IS PLENTY OF LOW LEVEL MOISTURE(PWATS ~1.5 IN) AND MODERATE
CAPE VALUES(~1100 J/KG)...SO GENERALLY HAVE 30 TO 40 PERCENT POPS
ON TODAY DURING THE AFTERNOON AND EARLY EVENING HOURS...DECREASING
FOR THE LATE NIGHT AND MORNING HOURS.
TEMPERATURE WILL MAX OUT NEAR 80 ALONG THE COAST TO THE MID 80S
INLAND. HIGH TEMPS MAY END UP BEING A FEW DEGREES COOLER IF CLOUD
AND PRECIPITATION REGIONS ARE MORE EXPANSIVE THAN ANTICIPATED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THERE WILL BE LESS COVERAGE OF PRECIPITATION AS
UPPER LEVEL SUPPORT WEAKENS. GUIDANCE ON WEDNESDAY IS STILL
UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND KEPT 30 PERCENT
POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
SSW FLO WILL CONTINUE TODAY THRU THU...WITH ISLTD OR SCTD SHOWERS
AND TSTMS EXPECTED ACRS THE REGION. MVFR/IFR CIGS LIKELY TO
DEVELOP OR OCCUR THRU ARND 15Z...THEN MAINLY VFR CONDITIONS
EXPECTED OVR THE AREA (OUTSIDE OF PCPN) THE REMAINDER OF THE DAY
INTO THIS EVENG. MORE MVFR/IFR CIGS COULD DEVELOP TNGT INTO WED
MORNG...AND AGAIN WED NGT INTO THU MORNG. A COLD FRONT WILL MOVE
ACRS THE AREA THU EVENG INTO EARLY FRI AFTN. HI PRES RETURNS FOR
LATE FRI THRU SUN.
&&
.MARINE...
NO FLAGS EXPECTED TODAY THRU WED...AS SSW FLO (AOB 15-20 KTS WITH
SEAS 2-4 FT) CONTINUES ARND HI PRES OFF THE CST. PRES GRADIENT
WILL INCREASE A BIT LATE WED THRU THU AHEAD OF APPROACHING COLD FRNT
PROGGED TO CROSS THE AREA THU NGT THRU FRI MORNG. ANY SCA CONDITIONS
THAT DEVELOP WILL BE MARGINAL AHEAD OF THE FRNT. WNA CONTINUES TO
FCST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED...BUT WILL
HOLD OFF ON ANY HEADLINE FOR NOW. WINDS WILL SHIFT TO THE NW OR N FRI
AFTN BEHIND THE FRNT.
&&
.EQUIPMENT...
THE OBSERVATION AT ORF IS NOT AVAILABLE. A TECH IS AT THE SITE THIS
MORNING AND HOPEFULLY SERVICE WILL BE RESTORED LATER TODAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/MAS/DAP
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...TMG
MARINE...TMG
EQUIPMENT...
000
FXUS61 KLWX 211416
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1016 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE ATLANTIC WILL CONTINUE TO AID A SOUTHERLY
FLOW THROUGH THURSDAY...BRINGING WARM AND HUMID CONDITIONS.
AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE EACH DAY. A
COLD FRONT WILL PASS THROUGH THE REGION THURSDAY NIGHT INTO
FRIDAY. COOLER CONDITIONS ARE EXPECTED OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK UPPER-LEVEL LOW PRESSURE REMAINS OVER SOUTHERN VIRGINIA INTO
THE CAROLINAS THIS MORNING WHILE SURFACE HIGH PRESSURE REMAINS
CENTERED OVER THE ATLANTIC OCEAN. PLENTY OF CLDS BANKED UP ALONG
AND EAST OF THE BLURDG...WHILE MOSUN SKIES PREVAIL TO THE W. 12Z
LWX RAOB INDICATES AN INVERSION ASSOCD W/ THE LOW CLDS UP TO ABT
H9. ABV THAT SNDG UNSTBL...W/ APPROX 1850 J/KG CAPE. HWVR CNVCTV
TEMPS /89F/ WL BE HARD TO REACH UNDER THE CLD CVR.
LAMP TEMPS RUNNING LWR THAN FCST MAXT. WHILE LAMP HAS HAD A GOOD
FEEL FOR ERODING LOW CLDS PAST CPL DAYS AND LIKE ITS HANDLING TDA
/SCT OUT LLVL MSTR BTWN 15-18Z/...TEMP HV BEEN RUNNING A LTL ON
THE COOL SIDE. INDEED...OUR OBSVD SNDG CUD WARM UP IN A HURRY.
THEREFORE...WL BE HOLDING ONTO GOING TEMP FCST.
THAT LEADS TO THE PCPN FCST. THE WARM AND HUMID AIR WILL LEAD TO
HIGH AMOUNTS OF INSTABILITY. NAM/GFS BUFKIT ARE INDICATING AROUND
2000-2500 J/KG OF MLCAPE THIS AFTERNOON. GOT SIMLR RSLTS IN SBCAPE
MODIFYING OBSVD SNDG TO 85/65. HWVR...THERE WAS ALSO ABT 50 J/KG
CINH. THIS INHIBITION WILL MAKE IT DIFFICULT FOR CONVECTION TO
DEVELOP. LIKE PRVS FCST...WHICH CONCENTRATED ON TERRAIN
CIRCULATIONS...A SURFACE TROUGH AND THE UPPER-LEVEL LOW ACTING AS
LIFTING MECHANISMS. MAIN PREMISE OF POPS REMAIN UNCHGD. WILL ALSO
HAVE TO MONITOR CONVECTION OVER THE MIDWEST. THIS MAY SURVIVE OFF
ITS COLD POOL AND BRING A THREAT FOR MORE WIDESPREAD CONVECTION
ALONG THE ALLEGHENY AND POTOMAC HIGHLANDS THIS EVENING. THE
HIGHEST POPS ARE LOCATED ACROSS THESE AREAS FOR THAT REASON.
THE THREAT FOR SEVERE T-STORMS THIS AFTERNOON AND EVENING SHOULD BE
LOW DUE TO THE STRONG CAPPING INVERSION. HOWEVER...IF THE LIFTING
MECHANISMS END UP BEING STRONG ENOUGH TO ERODE THE INVERSION...THEN
GUSTY WINDS AND HAIL ARE POSSIBLE.
ANY LEFTOVER CONVECTION WILL DISSIPATE OVERNIGHT DUE TO THE LOSS OF
DAYTIME HEATING. LOW CLOUDS AND AREAS OF FOG MAY DEVELOP AS MOISTURE
GETS TRAPPED UNDERNEATH THE NOCTURNAL INVERSION. HOWEVER...LOW
CLOUDS/FOG SHOULD NOT BE AS WIDESPREAD AS RECENT NIGHTS DUE TO A
HIGHER TEMP/DEWPOINT DEPRESSION AND A STRONGER GRADIENT. MIN TEMPS
WILL BE IN THE 60S ACROSS MOST AREAS TO THE LOWER 70S IN DOWNTOWN
WASHINGTON/BALTIMORE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
CNTRL MID-ATLANTIC IN WARM SECTOR OF MIDWEST LOW UNTIL A COLD FRONT
IN THE THURSDAY NIGHT TIMEFRAME. SFC HIGH WELL OFF ERN SEABOARD AIDS
SLY FLOW/MOISTURE ADVECTION. TEMPS ABOUT 10 DEGREES ABOVE NORMAL
WITH UPR 60S TO NEAR 70F DEWPOINTS. EXPECT A DIURNAL TREND IN PRECIP
COVERAGE WITH PREFRONTAL FORCING ENTERING THE AREA THURSDAY. SLIGHT
RISK FOR WEDNESDAY DUE TO POTENTIAL FOR STRAIGHT LINE WINDS FROM
ONGOING MCS ACTIVITY OVER THE OHIO VALLEY PUSHING EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
12Z ECMWF PROGS THE CD FROPA AS THURSDAY NIGHT (THERE HAS BEEN
FLUCTUATION FROM LATE THURSDAY TO FRIDAY MORNING). CANADIAN HIGH
PRESSURE BUILDS IN WITH A CRYSTAL CLEAR AND COOL WITH TEMPS 5-10
DEGREES BELOW NORMAL. SHORTWAVE OVER THE TN VLY ON SUNDAY SHOULD
REMAIN WEST OF THE LWX CWA...WILL HAVE TO MONITOR FOR INCREASED
POPS. AS OF NOW EXPECT SOME HIGH CLOUDS SUNDAY WITH A WARMING TREND
STARTING THAT CONTINUES INTO MID NEXT WEEK.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
LOW-LEVEL MOISTURE IS TRAPPED UNDERNEATH THE STILL PRESENT
NOCTURNAL INVERSION. LOW CLOUDS AND FOG JUST BGNG TO ERODE...AND
WILL IMPROVE TO VFR BY/ARND NOON. ISOLD SHOWERS AND T-STORMS ARE
POSSIBLE THIS AFTERNOON AND EVENING. THREAT TOO SLIM FOR TAF
INCLUSION. AREAS OF LOW CLOUDS/FOG MAY IMPACT THE TERMINALS LATE
TONIGHT.
DIURNAL THUNDERSTORM ACTIVITY WED/THUR WITH IFR CONDS POSSIBLE IN
THE HEAVIEST ONES. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY
FLOW WITH CLEAR CONDS SATURDAY. JUST SOME HIGH CLOUDS ON SUNDAY.
&&
.MARINE...
SOUTHERLY WINDS ARE EXPECTED OVER THE WATERS THROUGH TONIGHT. WIND
GUSTS WILL BE CLOSE TO SCA CRITERIA THIS AFTERNOON AND TONIGHT. HAVE
CAPPED GUSTS AROUND 15 KNOTS FOR NOW DUE TO THE RELATIVELY COOLER
WATERS. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND EVENING.
SLY FLOW WITH HIGH PRESSURE OFFSHORE AHEAD OF A COLD FRONT THAT
COMES THROUGH THURSDAY NIGHT. SLY CHANNELING TO 20 KT POSSIBLE WED
EVENING...AND THURSDAY. NWLY FLOW TO 20 KT POSSIBLE FRIDAY. LIGHT
AND VARIABLE FLOW THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES HAVE INCREASED TO AROUND ONE QUARTER FOOT ABOVE
NORMAL. ANOMALIES MAY INCREASE A BIT MORE DUE TO THE SOUTHERLY
FLOW...BUT WATER LEVELS SHOULD REMAIN BELOW THRESHOLDS FOR MINOR
FLOODING THROUGH TONIGHT. WILL HAVE TO WATCH SOUTHERLY FLOW
WEDNESDAY AND THURSDAY AS IT MAY SUPPORT AN INCREASE IN DEPARTURES
AGAIN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BJL
NEAR TERM...HTS/BJL
SHORT TERM...BAJ
LONG TERM...BAJ
AVIATION...HTS/BJL/BAJ
MARINE...BAJ/BJL
TIDES/COASTAL FLOODING...BJL
000
FXUS61 KPBZ 211402
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1002 AM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVECTIVE DEBRIS CLOUDS ARE CURRENTLY IN TRANSIT ACROSS THE
FORECAST AREA AND CONCURRENTLY DISSIPATING. TEMPERATURE READINGS
ARE SEVERAL DEGREES HIGHER THAN THIS TIME YESTERDAY AS WELL. WITH
LITTLE IN THE WAY TO PREVENT ABUNDANT INSOLATION ACROSS MUCH OF
THE AREA...AND THE FACT THAT THE LOW LEVEL THERMAL TONGUE WILL BE
TRAVERSING THE HEART OF THE CWA AT MAX HEATING...WITH 850 MB
TEMPERATURES NEARING +18C AROUND 21Z OVER PITTSBURGH WITH DECENT
BOUNDARY LAYER MIXING...IT WOULD SEEM TEMPERATURES SHOULD SURPASS
THOSE REACHED YESTERDAY. AS SUCH...HIGHS WERE INCREASED INTO THE
UPPER 80S FOR THE SOUTHERN TWO-THIRDS OF THE CWA...AND THE MID 80S
UP ALONG I-80.
WITH INCREASED HEATING AND SIMILAR DEWPOINTS AS COMPARED TO
YESTERDAY IN THE UPPER 60S...CAPE VALUES LOOK TO RUN UP TOWARD
3000 J/KG. GIVEN A WEAKLY SHEARED ENVIRONMENT AND NO SIGNIFICANT
SYNOPTIC OR MESOSCALE DISTURBANCE TO HARNESS THE CAPE...WIDESPREAD
THUNDERSTORM DEVELOPMENT IS NOT ANTICIPATED. HOWEVER...WEAK LOCAL
FORCING SEEMS LIKELY TO ALLOW FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ACROSS MUCH OF THE AREA BY
AFTERNOON...PARTICULARLY IN AREAS WEST OF PITTSBURGH AS WELL AS IN
THE RIDGES. POPS WERE INCREASED IN THESE AREAS. WITH WEAK SHEAR
AND WEAK MOMENTUM IN THE COLUMN...AS WELL AS A RATHER WARM
PROFILE...UPDRAFTS TO SUSTAIN HAIL DEVELOPMENT WILL BE DIFFICULT
TO MAINTAIN...HOWEVER A WIND GUST OR TWO MAY BE POSSIBLE OUT OF A
FEW OF THE CELLS. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVER CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION AND SHEAR VALUES
INCREASE. HAVE DECIDED TO GO WITH LIKELY POPS WED DUE TO THE
AFOREMENTIONED FACTORS. SPC CONTINUES TO KEEP THE AREA IN A SLIGHT
RISK FOR WED...SO WILL INCLUDE WORDING OF POSSIBLE SEVERE AND
MENTION IN HWO.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY...SO WILL
CONTINUE WITH LIKELY POPS. THURSDAYS NOT NEARLY AS UNSTABLE AS
TODAY OR WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL IN
QUESTION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FRONT WILL CLEAR THE AREA THU NIGHT AS A SHORTWAVE TROUGH SWINGS
THROUGH ON ITS HEELS. THIS WILL KEEP IN THE CHANCE FOR SHOWERS
THURSDAY NIGHT INTO EARLY FRIDAY. BEHIND THE COLD FRONT FRIDAY
TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED
FOR THE SECOND HALF OF FRIDAY INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY AND SUNDAY
MORNING.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS SHOULD PREVAIL FOR MUCH OF THE DAY. HOWEVER SINCE
WE REMAIN IN THE WARM SECTOR...PLENTY OF INSTABILITY WILL BE
PRESENT FOR THE DEVELOPMENT OF SOME THUNDERSTORMS ESPECIALLY IF WE
REACH CONVECTIVE TEMPERATURES TODAY...ALTHOUGH COVERAGE REMAINS IN
QUESTION. FOR NOW...WITH CONFIDENCE THAT ANY ONE THUNDERSTORM WILL
IMPACT A TAF SITE REMAINING LOW...CONTINUED VCTS MENTION. THERE
COULD BE TEMPORARY RESTRICTIONS TO VISIBILITY IN ANY SHOWERS THAT
DO DEVELOP...BUT ALSO OPTED TO KEEP THIS OUT AT THIS TIME.
OVERNIGHT FOG COULD ONCE AGAIN DEVELOP AS THE LOW LEVELS REMAIN
MOIST.
S-SW WIND WILL CONTINUE AT 5-10KTS TODAY AND OVERNIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND CROSSES THE REGION. BUILDING HIGH
PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPBZ 211345
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
945 AM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EXPECT MOST OF THE MORNING TO BE QUIET WITH INCREASING HIGH
CLOUDS...THE REMNANTS FROM LAST NIGHTS STORMS OVER THE MIDWEST.
CONVECTION WILL LIKELY HOLD OFF UNTIL THE AFTERNOON...WHEN THE
ATMOSPHERE RAPIDLY DESTABILIZES (CAPES OF 3000-3500 J/KG)...AND A
WEAK FRONTAL BOUNDARY MOVES THROUGH. THIS IS THE FIRST REAL
TRIGGER SINCE LAST WEEK. THE FRONT ITSELF IS WEAK...ONLY
NOTICEABLE BY A SURFACE WIND SHIFT. ADDITIONALLY...THERE IS NOT
MUCH UPPER LEVEL SUPPORT...WITH A SMALL SHORTWAVE SWINGING ACROSS
THE NORTH LATE TODAY. HOWEVER...MODELS ARE SHOWING LOW AND MID
LEVEL FORCING INCREASING WITH THE BOUNDARY AND LOW LEVEL MOISTURE
POOLING. THE UPPER LEVEL RIDGE WILL BEGIN TO BREAK DOWN THIS
AFTERNOON...AND IF WE CAN REACH OUR CONVECTIVE TEMP...IN THE MID
80S...NOT MUCH TO STOP THE PARCELS FROM RISING. THAT MAY BE THE
MOST IMPORTANT QUESTION...WHETHER WE CAN REACH THE CONVECTIVE
TEMP. WITH FULL SUN...HAVE NO DOUBT WE WOULD GO ABOVE THE MID
80S...HOWEVER CONCERNED ABOUT THE CIRRUS BLOW-OFF...FROM PREVIOUS
MIDWEST CONVECTION...THAT WILL MOVE OVER THE AREA TODAY. IF THE
HIGH CLOUDS HOLD TOGETHER...COULD NEGATE JUST ENOUGH SUNSHINE TO
KEEP OUR TEMPS DOWN A COUPLE OF DEGREES. WILL CONTINUE WITH HIGH
CHC POPS LATER TODAY...DOING SO WITH UNCERTAINTY ON IF WIDESPREAD
CONVECTION CAN DEVELOP. COULD SEE A SCENARIO WHERE A LINE OF
CONVECTION DEVELOPS OVER EC OHIO AND NW PA EARLY THIS AFTERNOON
AND BARRELS THROUGH...REACHING THE SE MTS BY EVE.
THE WIND FIELD ALOFT IS NOT OVERLY IMPRESSIVE WITH WINDS OF 25 TO
35 KTS...HOWEVER...WITH WBZ LEVELS RANGING FROM 9500-11000 HAIL
WOULD BE A GOOD BET.
SO IF CONVECTION DOES GET GOING THIS AFTERNOON...THERE WILL BE
SOME WIND GUSTS...BUT THINK THE MAIN CONCERN WOULD BE LARGE HAIL.
WILL INCLUDE THE WORDING OF GUSTY WINDS AND HAIL WITH THUNDERSTORMS.
FOR HIGHS TODAY...WILL LEAN CLOSE TO THE LATEST LAMP AS THOSE
NUMBERS HAVE WORKED WELL THAT PAST COUPLE OF DAYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVER CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION AND SHEAR VALUES
INCREASE. HAVE DECIDED TO GO WITH LIKELY POPS WED DUE TO THE
AFOREMENTIONED FACTORS. SPC CONTINUES TO KEEP THE AREA IN A SLIGHT
RISK FOR WED...SO WILL INCLUDE WORDING OF POSSIBLE SEVERE AND
MENTION IN HWO.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY...SO WILL
CONTINUE WITH LIKELY POPS. THURSDAYS NOT NEARLY AS UNSTABLE AS
TODAY OR WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL IN
QUESTION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FRONT WILL CLEAR THE AREA THU NIGHT AS A SHORTWAVE TROUGH SWINGS
THROUGH ON ITS HEELS. THIS WILL KEEP IN THE CHANCE FOR SHOWERS
THURSDAY NIGHT INTO EARLY FRIDAY. BEHIND THE COLD FRONT FRIDAY
TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED
FOR THE SECOND HALF OF FRIDAY INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY AND SUNDAY
MORNING.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS SHOULD PREVAIL FOR MUCH OF THE DAY. HOWEVER SINCE
WE REMAIN IN THE WARM SECTOR...PLENTY OF INSTABILITY WILL BE
PRESENT FOR THE DEVELOPMENT OF SOME THUNDERSTORMS ESPECIALLY IF WE
REACH CONVECTIVE TEMPERATURES TODAY...ALTHOUGH COVERAGE REMAINS IN
QUESTION. FOR NOW...WITH CONFIDENCE THAT ANY ONE THUNDERSTORM WILL
IMPACT A TAF SITE REMAINING LOW...CONTINUED VCTS MENTION. THERE
COULD BE TEMPORARY RESTRICTIONS TO VISIBILITY IN ANY SHOWERS THAT
DO DEVELOP...BUT ALSO OPTED TO KEEP THIS OUT AT THIS TIME.
OVERNIGHT FOG COULD ONCE AGAIN DEVELOP AS THE LOW LEVELS REMAIN
MOIST.
S-SW WIND WILL CONTINUE AT 5-10KTS TODAY AND OVERNIGHT.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND CROSSES THE REGION. BUILDING HIGH
PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 211338
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
938 AM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO THE AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND
COOLER TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THERE IS PLENTY OF LOW LEVEL MOISTURE(PWATS ~1.5 IN) AND MODERATE
CAPE VALUES(~1100 J/KG)...SO GENERALLY HAVE 30 TO 40 PERCENT POPS
ON TODAY DURING THE AFTERNOON AND EARLY EVENING HOURS...DECREASING
FOR THE LATE NIGHT AND MORNING HOURS.
TEMPERATURE WILL MAX OUT NEAR 80 ALONG THE COAST TO THE MID 80S
INLAND. HIGH TEMPS MAY END UP BEING A FEW DEGREES COOLER IF CLOUD
AND PRECIPITATION REGIONS ARE MORE EXPANSIVE THAN ANTICIPATED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THERE WILL BE LESS COVERAGE OF PRECIPITATION AS
UPPER LEVEL SUPPORT WEAKENS. GUIDANCE ON WEDNESDAY IS STILL
UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND KEPT 30 PERCENT
POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
SSW FLO WILL CONTINUE TODAY THRU THU...WITH ISLTD OR SCTD SHOWERS
AND TSTMS EXPECTED ACRS THE REGION. MVFR/IFR CIGS LIKELY TO
DEVELOP OR OCCUR THRU ARND 15Z...THEN MAINLY VFR CONDITIONS
EXPECTED OVR THE AREA (OUTSIDE OF PCPN) THE REMAINDER OF THE DAY
INTO THIS EVENG. MORE MVFR/IFR CIGS COULD DEVELOP TNGT INTO WED
MORNG...AND AGAIN WED NGT INTO THU MORNG. A COLD FRONT WILL MOVE
ACRS THE AREA THU EVENG INTO EARLY FRI AFTN. HI PRES RETURNS FOR
LATE FRI THRU SUN.
&&
.MARINE...
NO FLAGS EXPECTED TODAY THRU WED...AS SSW FLO (AOB 15-20 KTS WITH
SEAS 2-4 FT) CONTINUES ARND HI PRES OFF THE CST. PRES GRADIENT
WILL INCREASE A BIT LATE WED THRU THU AHEAD OF APPROACHING COLD FRNT
PROGGED TO CROSS THE AREA THU NGT THRU FRI MORNG. ANY SCA CONDITIONS
THAT DEVELOP WILL BE MARGINAL AHEAD OF THE FRNT. WNA CONTINUES TO
FCST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED...BUT WILL
HOLD OFF ON ANY HEADLINE FOR NOW. WINDS WILL SHIFT TO THE NW OR N FRI
AFTN BEHIND THE FRNT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/MAS/DAP
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...TMG
MARINE...TMG
000
FXUS61 KPHI 211236
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
836 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED JUST OFF THE SOUTHEASTERN UNITED
STATES COAST THROUGH THURSDAY. LOW PRESSURE WILL APPROACH FROM THE
WEST, PASSING TO OUR NORTH, AND WILL DRAG A COLD FRONT THROUGH THE
REGION LATE THURSDAY INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD IN
FROM THE WEST FOR THE WEEKEND BEFORE MOVING OFFSHORE LATER SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE PUBLIC PRODUCTS HAVE BEEN UPDATED TO INCLUDE A SMALL CHC FOR
SHOWERS THIS MORNING ACROSS THE ERN SHORE OF MD/DEL/SRN NJ.
HIGH PRESSURE WILL REMAIN ACROSS THE SOUTHERN ATLANTIC TODAY, WHICH
WILL KEEP OUR AREA UNDER A RETURN FLOW. THIS WILL KEEP A FLOW OF
WARM, MOIST AIR ACROSS THE AREA. PATCHY LOW CLOUDS AND FOG EARLY
THIS MORNING WILL BURN OFF MY MID-MORNING, AND EVENTUALLY LEAD TO A
PARTLY TO MOSTLY CLOUDY DAY. A FRONTAL BOUNDARY WILL TRY TO SINK
TOWARD OUR AREA FROM THE NORTH TODAY, BUT IS NOT EXPECTED TO REACH
THIS FAR SOUTHWARD. MODEL GUIDANCE INDICATE A SHORT WAVE MOVING TO
OUR NORTH ALONG THIS BOUNDARY DURING THE DAY, AND ANOTHER SHORT WAVE
IS EXPECTED TO SKIRT JUST TO OUR SOUTH. ANY ORGANIZED PRECIPITATION
WOULD LIKELY BE FOCUSED NEAR THESE AREAS. HOWEVER, WITH A WARM AND
MOIST AIRMASS ACROSS THE AREA, THERE WILL BE SOME INSTABILITY
THROUGH THE DAY. THIS COULD LEAD TO SOME ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA, MAINLY LATE IN THE DAY.
MAV/MET MOS GUIDANCE GAVE SOME DIFFERENT NUMBERS FOR HIGHS TODAY
WITH THE MET SEVERAL DEGREES WARMER THAN THE MAV. TAKING A LOOK AT
925 MB TEMPERATURES, WE DECIDED TO TAKE A BLEND OF THE MOS NUMBERS,
WHICH WOULD GIVE MID-UPPER 80S FROM MUCH OF THE AREA, WITH LOW-MID
80S FOR OUR EASTERN AND SOUTHERN AREAS. AREAS RIGHT ALONG THE COAST
MAY NOT REACH 80 DEGREES HOWEVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SYNOPTIC SITUATION OVERNIGHT DOES NOT CHANGE MUCH FROM THE
DAYTIME. A STRONGER SHORT WAVE/VORT MAX ALOFT IS FORECAST TO
APPROACH THE AREA OVERNIGHT, AT THE SAME TIME A WEAK SURFACE TROUGH
MAY MOVE ACROSS THE AREA. THERE COULD STILL BE SOME INSTABILITY
OVERNIGHT, WHICH COULD LEAD TO THE CHANCE FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA. WE LEFT FOG OUT OF THE
FORECAST OVERNIGHT AS THERE MAY BE ENOUGH MIXING TO PREVENT MUCH OF
THE DENSER FOG FROM DEVELOPING. A BLEND OF THE MAV/MET MOS WAS TAKEN
FOR OVERNIGHT LOWS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE DOMINATES OUR WEATHER OVER THE NEXT SEVERAL DAYS AS IT
SETS UP SHOP OVER THE SOUTHWESTERN ATLANTIC. WITH THE HIGH TO OUR
SOUTHEAST, WE WILL SEE A SOUTHWESTERLY FLOW CONTINUE ACROSS THE
REGION. THIS SOUTHWEST FLOW WILL ADVECT WARM AND MOIST AIR TO OUR
AREA AND WE WILL REMAIN ABOVE NORMAL FOR TEMPERATURES THROUGH AT
LEAST MID WEEK. WITH ALL THAT MOIST, WARM AIR, WE WILL ALSO START TO
DESTABILIZE. THIS WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH THE WEEK, MAINLY IN THE AFTERNOON AFTER
SUFFICIENT DAYTIME HEATING HAS OCCURRED AND CONVECTIVE TEMPERATURES
HAVE BEEN REACHED.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST ON THURSDAY, WITH
THE CENTER PASSING OFF TO OUR NORTH. THE ATTACHED COLD FRONT IS
FORECAST TO MOVE THROUGH OUR AREA THURSDAY INTO FRIDAY, MOST LIKELY
LATER IN THE DAY THURSDAY INTO EARLY FRIDAY. THE LATEST MODEL
GUIDANCE HAS SLOWED DOWN THE FRONTAL PASSAGE AND WITH LITTLE SUPPORT
OVERALL, WE HAVE OPTED TO KEEP THE FORECAST LARGELY THE SAME AND
LEAN A BIT MORE ON THE PROGRESSIVE SIDE.
THE FRONT PUSHES THROUGH AND OFFSHORE BY FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT, BRINGING IN SOME COOLER AND
DRIER AIR FOR THE HOLIDAY WEEKEND. THE MODELS HINT AT A
SHORTWAVE MOVING THROUGH THE MID LEVELS LATE SATURDAY OR SUNDAY WITH
A LIGHT SHOWER POSSIBLE. THE AIR LOOKS LIKE IT MIGHT BE TOO DRY FOR
ANYTHING TO MAKE IT TO THE SURFACE AND WE HAVE KEPT THE HOLIDAY
WEEKEND POP FREE.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CIGS/VSBYS ARE NOW DEVELOPING ACROSS THE TAF SITES. THE LOW
CLOUDS/FOG WILL BURN OFF THROUGH THE MID MORNING HOURS, AND
CONDITIONS WILL EVENTUALLY BECOME VFR. THERE IS A CHANCE FOR SOME
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON, BUT
CONFIDENCE IN THEM HITTING A PARTICULAR TAF SITE IS LOW, SO THEY
WERE LEFT OUT OF THE FORECAST FOR THE TIME BEING.
ANOTHER ROUND OF LOW CLOUDS/FOG IS POSSIBLE AGAIN TUESDAY NIGHT.
HOWEVER, THERE IS ALSO THE POSSIBILITY FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS OVERNIGHT AS WELL. CONFIDENCE IN THE SHOWERS
OCCURRING IS STILL LOW, SO THEY WERE LEFT OUT FOR NOW. ALSO, WITH
THE POTENTIAL FOR SOME MIXING TO OCCUR, SO WE DID NOT HIT THE LOW
CONDITIONS HARD JUST YET...WE`LL SEE HOW LATER GUIDANCE HANDLES THE
OVERNIGHT PERIOD.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE DURING THE EARLY MORNING HOURS. ALSO, SCATTERED
SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON AND EVENING,
MAY REDUCE CEILINGS AND VISIBILITIES AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW ADVISORY LEVELS THROUGH
TODAY INTO TONIGHT. HOWEVER, WINDS COULD PERIODICALLY GUST AROUND 20
KNOTS, ESPECIALLY LATER TODAY INTO TONIGHT. ALSO, SEAS WILL REMAIN
NEAR 4 FEET THROUGH THE PERIOD, AND MAY GET CLOSE TO 5 FEET
OVERNIGHT. CONFIDENCE IN CONDITIONS GETTING CLOSE TO ADVISORY LEVELS
IS NOT HIGH ENOUGH TO ISSUE AN ADVISORY.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WEDNESDAY THROUGH
THURSDAY. AS THIS FLOW STRENGTHENS, WINDS AND SEAS WILL GRADUALLY
INCREASE. SEAS WILL START TO RISE TO NEAR 5 FEET BY WEDNESDAY
AFTERNOON WITH WINDS STARTING TO GUST IN ADVANCE OF AN APPROACHING
COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE WEDNESDAY
AND THURSDAY ON THE OCEAN FRONT.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SMALL CRAFT ADVISORY CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW
CRITERIA THROUGH THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS
THE REGION.
WITH SUCH A WARM, MOIST AIRMASS IN PLACE THROUGH THURSDAY, THERE
WILL REMAIN A CHANCE FOR SOME PATCHY DENSE FOG TO FORM OVER THE AREA
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...MEOLA
AVIATION...ROBERTSON/MEOLA
MARINE...ROBERTSON/MEOLA
000
FXUS61 KAKQ 210902
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
502 AM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND COOLER
TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WARM AND HUMID AIRMASS COUPLED WITH 20 KT OF LOW LEVEL WIND SHEAR
AND WEAK MID LEVEL TROUGH IS PRODUCING SOME LIGHT SHOWER ACTIVITY
ACROSS NORTHERN NC. SOME OF THIS SHOWER ACTIVITY WILL MAKE ITS WAY
INTO THE WAKEFIELD CWA...HAVE BOOSTED POPS ACCORDINGLY. SOUTHWEST
SFC WINDS WILL STAY ABOVE 5 KT OVERNIGHT...WHICH WILL HAMPER ANY
CHANCE FOR FOG DEVELOPMENT. ANOTHER WARM AND HUMID NIGHT AHEAD AS
TEMPERATURES ONLY DROP INTO THE MID-UPPER 60S REGION-WIDE.
THERE WILL STILL BE PLENTY OF LOW LEVEL MOISTURE(PWATS ~1.7
IN) AND MODERATE CAPE VALUES(~1100 J/KG)...SO GENERALLY HAVE 30 TO
40 PERCENT POPS ON TUESDAY DURING THE AFTERNOON AND EARLY EVENING
HOURS...DECREASING FOR THE LATE NIGHT AND MORNING HOURS.
TEMPERATURE ON TUESDAY WILL MAX OUT NEAR 80 ALONG THE COAST TO THE
MID 80S INLAND. HIGH TEMPS MAY END UP BEING A FEW DEGREES COOLER
IF CLOUD AND PRECIPITATION REGIONS ARE MORE EXPANSIVE THAN ANTICIPATED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THERE WILL BE LESS COVERAGE OF PRECIPITATION AS
UPPER LEVEL SUPPORT WEAKENS. GUIDANCE ON WEDNESDAY IS STILL
UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND KEPT 30 PERCENT
POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
SSW FLO WILL CONTINUE TODAY THRU THU...WITH ISLTD OR SCTD SHOWERS
AND TSTMS EXPECTED ACRS THE REGION. MVFR/IFR CIGS LIKELY TO
DEVELOP OR OCCUR THRU ARND 15Z...THEN MAINLY VFR CONDITIONS
EXPECTED OVR THE AREA (OUTSIDE OF PCPN) THE REMAINDER OF THE DAY
INTO THIS EVENG. MORE MVFR/IFR CIGS COULD DEVELOP TNGT INTO WED
MORNG...AND AGAIN WED NGT INTO THU MORNG. A COLD FRONT WILL MOVE
ACRS THE AREA THU EVENG INTO EARLY FRI AFTN. HI PRES RETURNS FOR
LATE FRI THRU SUN.
&&
.MARINE...
NO FLAGS EXPECTED TODAY THRU WED...AS SSW FLO (AOB 15-20 KTS WITH
SEAS 2-4 FT) CONTINUES ARND HI PRES OFF THE CST. PRES GRADIENT
WILL INCREASE A BIT LATE WED THRU THU AHEAD OF APPROACHING COLD FRNT
PROGGED TO CROSS THE AREA THU NGT THRU FRI MORNG. ANY SCA CONDITIONS
THAT DEVELOP WILL BE MARGINAL AHEAD OF THE FRNT. WNA CONTINUES TO
FCST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED...BUT WILL
HOLD OFF ON ANY HEADLINE FOR NOW. WINDS WILL SHIFT TO THE NW OR N FRI
AFTN BEHIND THE FRNT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/DAP
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...TMG
MARINE...TMG
000
FXUS61 KPBZ 210823
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
423 AM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EXPECT MOST OF THE MORNING TO BE QUIET WITH INCREASING HIGH
CLOUDS...THE REMNANTS FROM LAST NIGHTS STORMS OVER THE MIDWEST.
CONVECTION WILL LIKELY HOLD OFF UNTIL THE AFTERNOON...WHEN THE
ATMOSPHERE RAPIDLY DESTABILIZES (CAPES OF 3000-3500 J/KG)...AND A
WEAK FRONTAL BOUNDARY MOVES THROUGH. THIS IS THE FIRST REAL
TRIGGER SINCE LAST WEEK. THE FRONT ITSELF IS WEAK...ONLY
NOTICEABLE BY A SURFACE WIND SHIFT. ADDITIONALLY...THERE IS NOT
MUCH UPPER LEVEL SUPPORT...WITH A SMALL SHORTWAVE SWINGING ACROSS
THE NORTH LATE TODAY. HOWEVER...MODELS ARE SHOWING LOW AND MID
LEVEL FORCING INCREASING WITH THE BOUNDARY AND LOW LEVEL MOISTURE
POOLING. THE UPPER LEVEL RIDGE WILL BEGIN TO BREAK DOWN THIS
AFTERNOON...AND IF WE CAN REACH OUR CONVECTIVE TEMP...IN THE MID
80S...NOT MUCH TO STOP THE PARCELS FROM RISING. THAT MAY BE THE
MOST IMPORTANT QUESTION...WHETHER WE CAN REACH THE CONVECTIVE
TEMP. WITH FULL SUN...HAVE NO DOUBT WE WOULD GO ABOVE THE MID
80S...HOWEVER CONCERNED ABOUT THE CIRRUS BLOW-OFF...FROM PREVIOUS
MIDWEST CONVECTION...THAT WILL MOVE OVER THE AREA TODAY. IF THE
HIGH CLOUDS HOLD TOGETHER...COULD NEGATE JUST ENOUGH SUNSHINE TO
KEEP OUR TEMPS DOWN A COUPLE OF DEGREES. WILL CONTINUE WITH HIGH
CHC POPS LATER TODAY...DOING SO WITH UNCERTAINTY ON IF WIDESPREAD
CONVECTION CAN DEVELOP. COULD SEE A SCENARIO WHERE A LINE OF
CONVECTION DEVELOPS OVER EC OHIO AND NW PA EARLY THIS AFTERNOON
AND BARRELS THROUGH...REACHING THE SE MTS BY EVE.
THE WIND FIELD ALOFT IS NOT OVERLY IMPRESSIVE WITH WINDS OF 25 TO
35 KTS...HOWEVER...WITH WBZ LEVELS RANGING FROM 9500-11000 HAIL
WOULD BE A GOOD BET.
SO IF CONVECTION DOES GET GOING THIS AFTERNOON...THERE WILL BE
SOME WIND GUSTS...BUT THINK THE MAIN CONCERN WOULD BE LARGE HAIL.
WILL INCLUDE THE WORDING OF GUSTY WINDS AND HAIL WITH THUNDERSTORMS.
FOR HIGHS TODAY...WILL LEAN CLOSE TO THE LATEST LAMP AS THOSE
NUMBERS HAVE WORKED WELL THAT PAST COUPLE OF DAYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVER CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION AND SHEAR VALUES
INCREASE. HAVE DECIDED TO GO WITH LIKELY POPS WED DUE TO THE
AFOREMENTIONED FACTORS. SPC CONTINUES TO KEEP THE AREA IN A SLIGHT
RISK FOR WED...SO WILL INCLUDE WORDING OF POSSIBLE SEVERE AND
MENTION IN HWO.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY...SO WILL
CONTINUE WITH LIKELY POPS. THURSDAYS NOT NEARLY AS UNSTABLE AS
TODAY OR WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL IN
QUESTION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FRONT WILL CLEAR THE AREA THU NIGHT AS A SHORTWAVE TROUGH SWINGS
THROUGH ON ITS HEELS. THIS WILL KEEP IN THE CHANCE FOR SHOWERS
THURSDAY NIGHT INTO EARLY FRIDAY. BEHIND THE COLD FRONT FRIDAY
TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED
FOR THE SECOND HALF OF FRIDAY INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY AND SUNDAY
MORNING.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
LIGHT SOUTH WINDS WILL REMAIN THROUGH THE OVERNIGHT. ANOTHER
ROUND OF MVFR FOG IS A GOOD POSSIBILITY THROUGH THE MID MORNING.
SCATTERED AFTERNOON THUNDERSTORMS ARE A POSSIBILITY...WITH
SLIGHTLY MORE COVERAGE EXPECTED THAN YESTERDAY. FOR NOW WILL
INCLUDE VCTS FROM KPIT NORTH AND WEST IN TERMINALS. DID NOT HAVE
ENOUGH CONFIDENCE IN YET ANOTHER ROUND OF MVFR FOG TO INCLUDE IN
30 HOUR PIT TAF...WITH THUNDERSTORM COVERAGE AND ASSOCIATED
PRECIPITATION LIKELY PLAYING A ROLE IN THIS FORECAST.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND PASSES ACROSS THE REGION. BUILDING
HIGH PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPHI 210810
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
410 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED JUST OFF THE SOUTHEASTERN UNITED
STATES COAST THROUGH THURSDAY. LOW PRESSURE WILL APPROACH FROM THE
WEST, PASSING TO OUR NORTH, AND WILL DRAG A COLD FRONT THROUGH THE
REGION LATE THURSDAY INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD IN
FROM THE WEST FOR THE WEEKEND BEFORE MOVING OFFSHORE LATER SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL REMAIN ACROSS THE SOUTHERN ATLANTIC TODAY, WHICH
WILL KEEP OUR AREA UNDER A RETURN FLOW. THIS WILL KEEP A FLOW OF
WARM, MOIST AIR ACROSS THE AREA. PATCHY LOW CLOUDS AND FOG EARLY
THIS MORNING WILL BURN OFF MY MID-MORNING, AND EVENTUALLY LEAD TO A
PARTLY TO MOSTLY CLOUDY DAY. A FRONTAL BOUNDARY WILL TRY TO SINK
TOWARD OUR AREA FROM THE NORTH TODAY, BUT IS NOT EXPECTED TO REACH
THIS FAR SOUTHWARD. MODEL GUIDANCE INDICATE A SHORT WAVE MOVING TO
OUR NORTH ALONG THIS BOUNDARY DURING THE DAY, AND ANOTHER SHORT WAVE
IS EXPECTED TO SKIRT JUST TO OUR SOUTH. ANY ORGANIZED PRECIPITATION
WOULD LIKELY BE FOCUSED NEAR THESE AREAS. HOWEVER, WITH A WARM AND
MOIST AIRMASS ACROSS THE AREA, THERE WILL BE SOME INSTABILITY
THROUGH THE DAY. THIS COULD LEAD TO SOME ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA, MAINLY LATE IN THE DAY.
MAV/MET MOS GUIDANCE GAVE SOME DIFFERENT NUMBERS FOR HIGHS TODAY
WITH THE MET SEVERAL DEGREES WARMER THAN THE MAV. TAKING A LOOK AT
925 MB TEMPERATURES, WE DECIDED TO TAKE A BLEND OF THE MOS NUMBERS,
WHICH WOULD GIVE MID-UPPER 80S FROM MUCH OF THE AREA, WITH LOW-MID
80S FOR OUR EASTERN AND SOUTHERN AREAS. AREAS RIGHT ALONG THE COAST
MAY NOT REACH 80 DEGREES HOWEVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SYNOPTIC SITUATION OVERNIGHT DOES NOT CHANGE MUCH FROM THE
DAYTIME. A STRONGER SHORT WAVE/VORT MAX ALOFT IS FORECAST TO
APPROACH THE AREA OVERNIGHT, AT THE SAME TIME A WEAK SURFACE TROUGH
MAY MOVE ACROSS THE AREA. THERE COULD STILL BE SOME INSTABILITY
OVERNIGHT, WHICH COULD LEAD TO THE CHANCE FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA. WE LEFT FOG OUT OF THE
FORECAST OVERNIGHT AS THERE MAY BE ENOUGH MIXING TO PREVENT MUCH OF
THE DENSER FOG FROM DEVELOPING. A BLEND OF THE MAV/MET MOS WAS TAKEN
FOR OVERNIGHT LOWS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE DOMINATES OUR WEATHER OVER THE NEXT SEVERAL DAYS AS IT
SETS UP SHOP OVER THE SOUTHWESTERN ATLANTIC. WITH THE HIGH TO OUR
SOUTHEAST, WE WILL SEE A SOUTHWESTERLY FLOW CONTINUE ACROSS THE
REGION. THIS SOUTHWEST FLOW WILL ADVECT WARM AND MOIST AIR TO OUR
AREA AND WE WILL REMAIN ABOVE NORMAL FOR TEMPERATURES THROUGH AT
LEAST MID WEEK. WITH ALL THAT MOIST, WARM AIR, WE WILL ALSO START TO
DESTABILIZE. THIS WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH THE WEEK, MAINLY IN THE AFTERNOON AFTER
SUFFICIENT DAYTIME HEATING HAS OCCURRED AND CONVECTIVE TEMPERATURES
HAVE BEEN REACHED.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST ON THURSDAY, WITH
THE CENTER PASSING OFF TO OUR NORTH. THE ATTACHED COLD FRONT IS
FORECAST TO MOVE THROUGH OUR AREA THURSDAY INTO FRIDAY, MOST LIKELY
LATER IN THE DAY THURSDAY INTO EARLY FRIDAY. THE LATEST MODEL
GUIDANCE HAS SLOWED DOWN THE FRONTAL PASSAGE AND WITH LITTLE SUPPORT
OVERALL, WE HAVE OPTED TO KEEP THE FORECAST LARGELY THE SAME AND
LEAN A BIT MORE ON THE PROGRESSIVE SIDE.
THE FRONT PUSHES THROUGH AND OFFSHORE BY FRIDAY MORNING. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT, BRINGING IN SOME COOLER AND
DRIER AIR FOR THE HOLIDAY WEEKEND. THE MODELS HINT AT A
SHORTWAVE MOVING THROUGH THE MID LEVELS LATE SATURDAY OR SUNDAY WITH
A LIGHT SHOWER POSSIBLE. THE AIR LOOKS LIKE IT MIGHT BE TOO DRY FOR
ANYTHING TO MAKE IT TO THE SURFACE AND WE HAVE KEPT THE HOLIDAY
WEEKEND POP FREE.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CIGS/VSBYS ARE NOW DEVELOPING ACROSS THE TAF SITES. THE LOW
CLOUDS/FOG WILL BURN OFF THROUGH THE MID MORNING HOURS, AND
CONDITIONS WILL EVENTUALLY BECOME VFR. THERE IS A CHANCE FOR SOME
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON, BUT
CONFIDENCE IN THEM HITTING A PARTICULAR TAF SITE IS LOW, SO THEY
WERE LEFT OUT OF THE FORECAST FOR THE TIME BEING.
ANOTHER ROUND OF LOW CLOUDS/FOG IS POSSIBLE AGAIN TUESDAY NIGHT.
HOWEVER, THERE IS ALSO THE POSSIBILITY FOR ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS OVERNIGHT AS WELL. CONFIDENCE IN THE SHOWERS
OCCURRING IS STILL LOW, SO THEY WERE LEFT OUT FOR NOW. ALSO, WITH
THE POTENTIAL FOR SOME MIXING TO OCCUR, SO WE DID NOT HIT THE LOW
CONDITIONS HARD JUST YET...WE`LL SEE HOW LATER GUIDANCE HANDLES THE
OVERNIGHT PERIOD.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE DURING THE EARLY MORNING HOURS. ALSO, SCATTERED
SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON AND EVENING,
MAY REDUCE CEILINGS AND VISIBILITIES AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WINDS AND SEAS ARE FORECAST TO REMAIN BELOW ADVISORY LEVELS THROUGH
TODAY INTO TONIGHT. HOWEVER, WINDS COULD PERIODICALLY GUST AROUND 20
KNOTS, ESPECIALLY LATER TODAY INTO TONIGHT. ALSO, SEAS WILL REMAIN
NEAR 4 FEET THROUGH THE PERIOD, AND MAY GET CLOSE TO 5 FEET
OVERNIGHT. CONFIDENCE IN CONDITIONS GETTING CLOSE TO ADVISORY LEVELS
IS NOT HIGH ENOUGH TO ISSUE AN ADVISORY.
OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WEDNESDAY THROUGH
THURSDAY. AS THIS FLOW STRENGTHENS, WINDS AND SEAS WILL GRADUALLY
INCREASE. SEAS WILL START TO RISE TO NEAR 5 FEET BY WEDNESDAY
AFTERNOON WITH WINDS STARTING TO GUST IN ADVANCE OF AN APPROACHING
COLD FRONT. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE WEDNESDAY
AND THURSDAY ON THE OCEAN FRONT.
THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SMALL CRAFT ADVISORY CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW
CRITERIA THROUGH THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS
THE REGION.
WITH SUCH A WARM, MOIST AIRMASS IN PLACE THROUGH THURSDAY, THERE
WILL REMAIN A CHANCE FOR SOME PATCHY DENSE FOG TO FORM OVER THE AREA
WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...MEOLA
AVIATION...ROBERTSON/MEOLA
MARINE...ROBERTSON/MEOLA
000
FXUS61 KLWX 210758
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
358 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE ATLANTIC WILL CONTINUE TO AID A SOUTHERLY
FLOW THROUGH THURSDAY...BRINGING WARM AND HUMID CONDITIONS. AFTERNOON
AND EVENING THUNDERSTORMS ARE POSSIBLE EACH DAY. A COLD FRONT
WILL PASS THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. COOLER
CONDITIONS ARE EXPECTED OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WEAK UPPER-LEVEL LOW PRESSURE REMAINS OVER SOUTHERN VIRGINIA INTO
THE CAROLINAS EARLY THIS MORNING WHILE SURFACE HIGH PRESSURE REMAINS
CENTERED OVER THE ATLANTIC OCEAN.
A SOUTHERLY FLOW AROUND THE SURFACE HIGH HAS CAUSED WARM AND HUMID
CONDITIONS EARLY THIS MORNING. PLENTY OF MOISTURE IS TRAPPED
UNDERNEATH THE NOCTURNAL INVERSION AND THIS WILL CAUSE LOW CLOUDS
ALONG WITH AREAS OF FOG EARLY. FOG MAY BE LOCALLY DENSE IN VALLEYS
AND RURAL AREAS.
LOW CLOUDS AND FOG WILL MIX OUT BY MID-MORNING AND A SOUTHERLY FLOW
WILL CONTINUE TO USHER IN WARM AND HUMID CONDITIONS. MAX TEMPS TODAY
SHOULD BE SEVERAL DEGREES WARMER THAN MONDAY...RANGING FROM THE 70S
IN THE MOUNTAINS TO THE MID AND UPPER 80S ACROSS MOST OTHER
LOCATIONS. LEANED CLOSER TO THE MAV GUIDANCE FOR MAX TEMPS WHICH IS
A BIT WARMER THAN OTHER GUIDANCE. THE MAV HAS BEEN PERFORMING WELL
AND THERE SHOULD BE ENOUGH SUNSHINE AND MIXING FOR HIGHER TEMPS.
THE WARM AND HUMID AIR WILL LEAD TO HIGH AMOUNTS OF INSTABILITY.
NAM/GFS BUFKIT ARE INDICATING AROUND 2000-2500 J/KG OF MLCAPE THIS
AFTERNOON. A CAPPING INVERSION AROUND 5KFT WILL MAKE IT DIFFICULT
FOR CONVECTION TO DEVELOP. DID ALLOW FOR A CHANCE FOR
SHOWERS/T-STORMS ANYWAY DUE TO TERRAIN CIRCULATION...A SURFACE
TROUGH AND THE UPPER-LEVEL LOW ACTING AS LIFTING MECHANISMS. WILL
ALSO HAVE TO MONITOR CONVECTION OVER THE MIDWEST. THIS MAY SURVIVE
OFF ITS COLD POOL AND BRING A THREAT FOR MORE WIDESPREAD CONVECTION
ALONG THE ALLEGHENY AND POTOMAC HIGHLANDS THIS EVENING. THE HIGHEST
POPS ARE LOCATED ACROSS THESE AREAS FOR THAT REASON.
THE THREAT FOR SEVERE T-STORMS THIS AFTERNOON AND EVENING SHOULD BE
LOW DUE TO THE STRONG CAPPING INVERSION. HOWEVER...IF THE LIFTING
MECHANISMS END UP BEING STRONG ENOUGH TO ERODE THE INVERSION...THEN
GUSTY WINDS AND HAIL ARE POSSIBLE.
ANY LEFTOVER CONVECTION WILL DISSIPATE OVERNIGHT DUE TO THE LOSS OF
DAYTIME HEATING. LOW CLOUDS AND AREAS OF FOG MAY DEVELOP AS MOISTURE
GETS TRAPPED UNDERNEATH THE NOCTURNAL INVERSION. HOWEVER...LOW
CLOUDS/FOG SHOULD NOT BE AS WIDESPREAD AS RECENT NIGHTS DUE TO A
HIGHER TEMP/DEWPOINT DEPRESSION AND A STRONGER GRADIENT. MIN TEMPS
WILL BE IN THE 60S ACROSS MOST AREAS TO THE LOWER 70S IN DOWNTOWN
WASHINGTON/BALTIMORE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
CNTRL MID-ATLANTIC IN WARM SECTOR OF MIDWEST LOW UNTIL A COLD FRONT
IN THE THURSDAY NIGHT TIMEFRAME. SFC HIGH WELL OFF ERN SEABOARD AIDS
SLY FLOW/MOISTURE ADVECTION. TEMPS ABOUT 10 DEGREES ABOVE NORMAL
WITH UPR 60S TO NEAR 70F DEWPOINTS. EXPECT A DIURNAL TREND IN PRECIP
COVERAGE WITH PREFRONTAL FORCING ENTERING THE AREA THURSDAY. SLIGHT
RISK FOR WEDNESDAY DUE TO POTENTIAL FOR STRAIGHT LINE WINDS FROM
ONGOING MCS ACTIVITY OVER THE OHIO VALLEY PUSHING EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
12Z ECMWF PROGS THE CD FROPA AS THURSDAY NIGHT (THERE HAS BEEN
FLUCTUATION FROM LATE THURSDAY TO FRIDAY MORNING). CANADIAN HIGH
PRESSURE BUILDS IN WITH A CRYSTAL CLEAR AND COOL WITH TEMPS 5-10
DEGREES BELOW NORMAL. SHORTWAVE OVER THE TN VLY ON SUNDAY SHOULD
REMAIN WEST OF THE LWX CWA...WILL HAVE TO MONITOR FOR INCREASED
POPS. AS OF NOW EXPECT SOME HIGH CLOUDS SUNDAY WITH A WARMING TREND
STARTING THAT CONTINUES INTO MID NEXT WEEK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
LOW-LEVEL MOISTURE IS TRAPPED UNDERNEATH THE NOCTURNAL INVERSION.
LOW CLOUDS AND FOG ARE EXPECTED WITH IFR/SUBIFR CONDITIONS EARLY
THIS MORNING. CIGS/VSBYS WILL IMPROVE BY MID MORNING AND SOUTHERLY
WINDS ARE EXPECTED THIS AFTERNOON WITH GUSTS AROUND 15 KNOTS
EXPECTED. SCATTERED SHOWERS AND T-STORMS ARE POSSIBLE THIS AFTERNOON
AND EVENING. AREAS OF LOW CLOUDS/FOG MAY IMPACT THE TERMINALS LATE
TONIGHT.
DIURNAL THUNDERSTORM ACTIVITY WED/THUR WITH IFR CONDS POSSIBLE IN
THE HEAVIEST ONES. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY
FLOW WITH CLEAR CONDS SATURDAY. JUST SOME HIGH CLOUDS ON SUNDAY.
&&
.MARINE...
SOUTHERLY WINDS ARE EXPECTED OVER THE WATERS THROUGH TONIGHT. WIND
GUSTS WILL BE CLOSE TO SCA CRITERIA THIS AFTERNOON AND TONIGHT. HAVE
CAPPED GUSTS AROUND 15 KNOTS FOR NOW DUE TO THE RELATIVELY COOLER
WATERS. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND EVENING.
SLY FLOW WITH HIGH PRESSURE OFFSHORE AHEAD OF A COLD FRONT THAT
COMES THROUGH THURSDAY NIGHT. SLY CHANNELING TO 20 KT POSSIBLE WED
EVENING...AND THURSDAY. NWLY FLOW TO 20 KT POSSIBLE FRIDAY. LIGHT
AND VARIABLE FLOW THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES HAVE INCREASED TO AROUND ONE QUARTER FOOT ABOVE
NORMAL. ANOMALIES MAY INCREASE A BIT MORE DUE TO THE SOUTHERLY
FLOW...BUT WATER LEVELS SHOULD REMAIN BELOW THRESHOLDS FOR MINOR
FLOODING THROUGH TONIGHT. WILL HAVE TO WATCH SOUTHERLY FLOW
WEDNESDAY AND THURSDAY AS IT MAY SUPPORT AN INCREASE IN DEPARTURES
AGAIN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BAJ
LONG TERM...BAJ
AVIATION...BAJ/BJL
MARINE...BAJ/BJL
TIDES/COASTAL FLOODING...BJL
000
FXUS61 KAKQ 210756
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
356 AM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND COOLER
TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WARM AND HUMID AIRMASS COUPLED WITH 20 KT OF LOW LEVEL WIND SHEAR
AND WEAK MID LEVEL TROUGH IS PRODUCING SOME LIGHT SHOWER ACTIVITY
ACROSS NORTHERN NC. SOME OF THIS SHOWER ACTIVITY WILL MAKE ITS WAY
INTO THE WAKEFIELD CWA...HAVE BOOSTED POPS ACCORDINGLY. SOUTHWEST
SFC WINDS WILL STAY ABOVE 5 KT OVERNIGHT...WHICH WILL HAMPER ANY
CHANCE FOR FOG DEVELOPMENT. ANOTHER WARM AND HUMID NIGHT AHEAD AS
TEMPERATURES ONLY DROP INTO THE MID-UPPER 60S REGION-WIDE.
THERE WILL STILL BE PLENTY OF LOW LEVEL MOISTURE(PWATS ~1.7
IN) AND MODERATE CAPE VALUES(~1100 J/KG)...SO GENERALLY HAVE 30 TO
40 PERCENT POPS ON TUESDAY DURING THE AFTERNOON AND EARLY EVENING
HOURS...DECREASING FOR THE LATE NIGHT AND MORNING HOURS.
TEMPERATURE ON TUESDAY WILL MAX OUT NEAR 80 ALONG THE COAST TO THE
MID 80S INLAND. HIGH TEMPS MAY END UP BEING A FEW DEGREES COOLER
IF CLOUD AND PRECIPITATION REGIONS ARE MORE EXPANSIVE THAN ANTICIPATED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THERE WILL BE LESS COVERAGE OF PRECIPITATION AS
UPPER LEVEL SUPPORT WEAKENS. GUIDANCE ON WEDNESDAY IS STILL
UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND KEPT 30 PERCENT
POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SSW FLO WILL CONTINUE TODAY THRU THU...WITH ISLTD OR SCTD SHOWERS
AND TSTMS EXPECTED ACRS THE REGION. MVFR/IFR CIGS LIKELY TO
DEVELOP OR OCCUR THRU ARND 15Z...THEN MAINLY VFR CONDITIONS
EXPECTED OVR THE AREA (OUTSIDE OF PCPN) THE REMAINDER OF THE DAY
INTO THIS EVENG. MORE MVFR/IFR CIGS COULD DEVELOP TNGT INTO WED
MORNG...AND AGAIN WED NGT INTO THU MORNG. A COLD FRONT WILL MOVE
ACRS THE AREA THU EVENG INTO EARLY FRI AFTN. HI PRES RETURNS FOR
LATE FRI THRU SUN.
&&
.MARINE...
NO FLAGS EXPECTED AS SRLY FLOW (AOB 15KTS WITH SEAS 2-4 FT) CONTS
ARND HIGH PRS OFF THE COAST THROUGH MID WEEK. PRS GRDNT INCRS LATE
WED AHEAD OF APPRCHG CDFRNT PROGGED TO CROSS THE AREA THURS NITE.
ANY SCA CDNTNS THAT DVLP WILL BE MARGINAL AHEAD OF SAID FRNT. WNA
CONTS TO FORECAST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED
BUT WILL HOLD OFF ON ANY HEADLINE THIS FAR OUT FOR NOW.
WNDS SHFT INTO NW THEN N BEHIND FRNT FRI. NXT THREAT FOR SCA CNDTNS
COMES FRI NITE/ERLY SAT WITH A DECENT CAA SURGE XPCTD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/DAP
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...TMG
MARINE...MPR
000
FXUS61 KPBZ 210718
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
318 AM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUIET NIGHT ACROSS THE REGION UNDER STRENGTHENING RIDGE. LARGE
AREA OF ACTIVITY WELL TO THE WEST AND ANOTHER AREA SWINGING INTO
SOUTHERN CANADA.
EXPECT MOST OF THE MORNING TO BE QUIET WITH INCREASING HIGH
CLOUDS...THE REMNANTS OF THE LARGE AREA OF STORMS OVER THE
MIDWEST. CONVECTION WILL LIKELY HOLD OFF UNTIL THE AFTERNOON...
WHEN THE ATMOSPHERE RAPIDLY DESTABILIZES (CAPES OF 3000-3500
J/KG)...AND A WEAK FRONTAL BOUNDARY MOVES THROUGH. THIS IS THE
FIRST REAL TRIGGER SINCE LAST WEEK. THE FRONT ITSELF IS WEAK...
ONLY NOTICEABLE BY A SURFACE WIND SHIFT WITH LITTLE TO NO UPPER
LEVEL SUPPORT. HOWEVER...MODELS ARE SHOWING LOW AND MID LEVEL
FORCING INCREASING WITH THE BOUNDARY AND LOW LEVEL MOISTURE
POOLING. THE UPPER LEVEL RIDGE WILL BEGIN TO BREAK DOWN THIS
AFTERNOON AND IF WE CAN REACH OUR CONVECTIVE TEMP...IN THE MID
80S...NOT MUCH TO STOP THE PARCELS FROM RISING. THAT MAY BE THE
MOST IMPORTANT QUESTION...WHETHER WE CAN REACH THE CONVECTIVE
TEMP. WITH FULL SUN...HAVE NO DOUBT WE WOULD GO ABOVE THE MID
80S...HOWEVER AM CONCERNED ABOUT THE CIRRUS BLOW-OFF...FROM MIDWEST
CONVECTION...THAT WILL MOVE OVER THE AREA TODAY. IF THE HIGH
CLOUDS HOLD TOGETHER...COULD NEGATE JUST ENOUGH SUNSHINE TO KEEP
OUR TEMPS DOWN A FEW DEGREES. WILL CONTINUE WITH HIGH CHC POPS
LATER TODAY...DOING SO WITH UNCERTAINTY ON IF WE CAN GET MORE
WIDESPREAD CONVECTION TO DEVELOP. COULD SEE A SCENARIO WHERE A
LINE OF CONVECTION DEVELOPS OVER EC OHIO AND NW PA EARLY THIS
AFTERNOON AND BARRELS THROUGH...REACHING THE SE MTS BY EVE.
THE WIND FIELD ALOFT IS NOT OVERLY IMPRESSIVE WITH WINDS OF 25 TO
35 KTS...HOWEVER...WITH WBZ LEVELS RANGING FROM 9500-11000 HAIL
WOULD BE A GOOD BET.
SO IF CONVECTION DOES GET GOING THIS AFTERNOON...THERE WILL BE
SOME WIND GUSTS...BUT THINK THE MAIN CONCERN WOULD BE LARGE HAIL.
FOR HIGHS TODAY...WILL LEAN CLOSE TO THE LATEST LAMP AS THOSE
NUMBERS HAVE WORKED WELL THAT PAST COUPLE OF DAYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVERY CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION. HAVE DECIDED TO GO
WITH LIKELY POPS WED DUE TO THE AFOREMENTIONED FACTORS.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY SO WILL
CONTINUE WITH LIKELY POPS. THURSDAY NOT NEARLY AS UNSTABLE AS
TODAY AND WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL
IN QUESTION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FRONT WILL CLEAR THE AREA THU NIGHT AS A SHORTWAVE TROUGH SWINGS
THROUGH ON ITS HEELS. THIS WILL KEEP IN THE CHANCE FOR SHOWERS
THURSDAY NIGHT INTO EARLY FRIDAY. BEHIND THE COLD FRONT FRIDAY
TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED
FOR THE SECOND HALF OF FRIDAY INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY AND SUNDAY
MORNING.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
LIGHT SOUTH WINDS WILL REMAIN THROUGH THE OVERNIGHT. ANOTHER
ROUND OF MVFR FOG IS A GOOD POSSIBILITY THROUGH THE MID MORNING.
SCATTERED AFTERNOON THUNDERSTORMS ARE A POSSIBILITY...WITH
SLIGHTLY MORE COVERAGE EXPECTED THAN YESTERDAY. FOR NOW WILL
INCLUDE VCTS FROM KPIT NORTH AND WEST IN TERMINALS. DID NOT HAVE
ENOUGH CONFIDENCE IN YET ANOTHER ROUND OF MVFR FOG TO INCLUDE IN
30 HOUR PIT TAF...WITH THUNDERSTORM COVERAGE AND ASSOCIATED
PRECIPITATION LIKELY PLAYING A ROLE IN THIS FORECAST.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND PASSES ACROSS THE REGION. BUILDING
HIGH PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 210547
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
147 AM EDT TUE MAY 21 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND COOLER
TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
PULSE-TYPE CONVECTION HAS BEGUN TO WANE THIS EVENING. THERE IS
STILL ENOUGH SHORTWAVE ENERGY ALOFT AND PLENTY OF SUBTROPICAL SFC
MOISTURE AVAILABLE (IT IS BEING PULLED IN ON SW FLOW FROM THE
ATLANTIC) TO KEEP LIGHT TO MODERATE RAIN SHOWERS GOING THROUGH THE
REMAINDER OF THIS EVENING. PRECIP WILL THEN TAPER OFF OVERNIGHT.
SOUTHWEST SFC WINDS WILL STAY ABOVE 5 KT OVERNIGHT...WHICH WILL
HAMPER ANY CHANCE FOR FOG DEVELOPMENT. ANOTHER WARM AND HUMID
NIGHT AHEAD AS TEMPERATURES ONLY DROP INTO THE MID-UPPER 60S
REGIONWIDE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
ON TUESDAY AND WEDNESDAY...THERE WILL BE LESS COVERAGE OF
PRECIPITATION AS UPPER LEVEL SUPPORT WEAKENS. THERE WILL STILL BE
PLENTY OF LOW LEVEL MOISTURE AND GENERALLY HAVE 30 TO 40 PERCENT
POPS ON TUESDAY DURING THE AFTERNOON AND EARLY EVENING HOURS...
DECREASING FOR THE LATE NIGHT AND MORNING HOURS. GUIDANCE ON
WEDNESDAY IS STILL UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND
KEPT 30 PERCENT POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SSW FLO WILL CONTINUE TODAY THRU THU...WITH ISLTD OR SCTD SHOWERS
AND TSTMS EXPECTED ACRS THE REGION. MVFR/IFR CIGS LIKELY TO
DEVELOP OR OCCUR THRU ARND 15Z...THEN MAINLY VFR CONDITIONS
EXPECTED OVR THE AREA (OUTSIDE OF PCPN) THE REMAINDER OF THE DAY
INTO THIS EVENG. MORE MVFR/IFR CIGS COULD DEVELOP TNGT INTO WED
MORNG...AND AGAIN WED NGT INTO THU MORNG. A COLD FRONT WILL MOVE
ACRS THE AREA THU EVENG INTO EARLY FRI AFTN. HI PRES RETURNS FOR
LATE FRI THRU SUN.
&&
.MARINE...
NO FLAGS EXPECTED AS SRLY FLOW (AOB 15KTS WITH SEAS 2-4 FT) CONTS
ARND HIGH PRS OFF THE COAST THROUGH MID WEEK. PRS GRDNT INCRS LATE
WED AHEAD OF APPRCHG CDFRNT PROGGED TO CROSS THE AREA THURS NITE.
ANY SCA CDNTNS THAT DVLP WILL BE MARGINAL AHEAD OF SAID FRNT. WNA
CONTS TO FORECAST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED
BUT WILL HOLD OFF ON ANY HEADLINE THIS FAR OUT FOR NOW.
WNDS SHFT INTO NW THEN N BEHIND FRNT FRI. NXT THREAT FOR SCA CNDTNS
COMES FRI NITE/ERLY SAT WITH A DECENT CAA SURGE XPCTD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...TMG
MARINE...MPR
000
FXUS61 KPBZ 210515 AAC
AFDPBZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
115 AM EDT TUE MAY 21 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TODAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
QUIET NIGHT ACROSS THE REGION UNDER STRENGTHENING RIDGE. LARGE
AREA OF ACTIVITY WELL TO THE WEST AND ANOTHER AREA SWINGING INTO
SOUTHERN CANADA.
EXPECT MOST OF THE MORNING TO BE QUIET WITH INCREASING HIGH
CLOUDS...THE REMNANTS OF THE LARGE AREA OF STORMS OVER THE
MIDWEST. CONVECTION WILL LIKELY HOLD OFF UNTIL THE AFTERNOON...
WHEN THE ATMOSPHERE RAPIDLY DESTABILIZES (CAPES OF 3000-3500
J/KG)...AND A WEAK FRONTAL BOUNDARY MOVES THROUGH. THIS IS THE
FIRST REAL TRIGGER SINCE LAST WEEK. THE FRONT ITSELF IS WEAK...
ONLY NOTICEABLE BY A SURFACE WIND SHIFT WITH LITTLE TO NO UPPER
LEVEL SUPPORT. HOWEVER...MODELS ARE SHOWING LOW AND MID LEVEL
FORCING INCREASING WITH THE BOUNDARY AND LOW LEVEL MOISTURE
POOLING. THE UPPER LEVEL RIDGE WILL BEGIN TO BREAK DOWN THIS
AFTERNOON AND IF WE CAN REACH OUR CONVECTIVE TEMP...IN THE MID
80S...NOT MUCH TO STOP THE PARCELS FROM RISING. THAT MAY BE THE
MOST IMPORTANT QUESTION...WHETHER WE CAN REACH THE CONVECTIVE
TEMP. WITH FULL SUN...HAVE NO DOUBT WE WOULD GO ABOVE THE MID
80S...HOWEVER AM CONCERNED ABOUT THE CIRRUS BLOW-OFF...FROM MIDWEST
CONVECTION...THAT WILL MOVE OVER THE AREA TODAY. IF THE HIGH
CLOUDS HOLD TOGETHER...COULD NEGATE JUST ENOUGH SUNSHINE TO KEEP
OUR TEMPS DOWN A FEW DEGREES. WILL CONTINUE WITH HIGH CHC POPS
LATER TODAY...DOING SO WITH UNCERTAINTY ON IF WE CAN GET MORE
WIDESPREAD CONVECTION TO DEVELOP. COULD SEE A SCENARIO WHERE A
LINE OF CONVECTION DEVELOPS OVER EC OHIO AND NW PA EARLY THIS
AFTERNOON AND BARRELS THROUGH...REACHING THE SE MTS BY EVE.
THE WIND FIELD ALOFT IS NOT OVERLY IMPRESSIVE WITH WINDS OF 25 TO
35 KTS...HOWEVER...WITH WBZ LEVELS RANGING FROM 9500-11000 HAIL
WOULD BE A GOOD BET.
SO IF CONVECTION DOES GET GOING THIS AFTERNOON...THERE WILL BE
SOME WIND GUSTS...BUT THINK THE MAIN CONCERN WOULD BE LARGE HAIL.
FOR HIGHS TODAY...WILL LEAN CLOSE TO THE LATEST LAMP AS THOSE
NUMBERS HAVE WORKED WELL THAT PAST COUPLE OF DAYS.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
BOUNDARY WASHES OUT THIS EVENING...AND WITH THE LOSS OF DAYTIME
HEATING...CONVECTION SHOULD DISSIPATE. AS THE RIDGE CONTINUES TO
WEAKEN...WAVES OF ENERGY...BREAKING AWAY FROM THE MAIN MIDWEST
SYSTEM...WILL RIDE OVER TOP OF WHAT IS LEFT OF THE RIDGE THROUGH
NORTHERN PA. WILL GO WITH LOW CHC POPS ACROSS THE NORTH AND SCHC
IN THE SOUTH. ATMOSPHERE STABILIZES OVERNIGHT AND ANY NOTICEABLE
FORCING IS SPARSE.
EXPECT CONVECTION TO GET GOING AGAIN LATE WEDNESDAY AS THE ENTIRE
SYSTEM CREEPS EVERY CLOSER TO THE UPPER OHIO VALLEY. ATMOSPHERE
WILL AGAIN DESTABILIZE AND THE UPPER LEVEL SUPPORT IMPROVES AS THE
RIDGE CONTINUES TO BREAK DOWN. WIND FIELD ALOFT STRENGTHENS
PULLING MORE DEEP MOISTURE INTO THE REGION. HAVE DECIDED TO GO
WITH LIKELY POPS WED DUE TO THE AFOREMENTIONED FACTORS.
SLOW MOVING FRONT DRIFTS THROUGH THE AREA ON THURSDAY SO WILL
CONTINUE WITH LIKELY POPS. THURSDAY NOT NEARLY AS UNSTABLE AS
TODAY AND WEDNESDAY...SO AMOUNT AND STRENGTH OF CONVECTION STILL
IN QUESTION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FRONT WILL CLEAR THE AREA THU NIGHT AS A SHORTWAVE TROUGH SWINGS
THROUGH ON ITS HEELS. THIS WILL KEEP IN THE CHANCE FOR SHOWERS
THURSDAY NIGHT INTO EARLY FRIDAY. BEHIND THE COLD FRONT FRIDAY
TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED
FOR THE SECOND HALF OF FRIDAY INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY AND SUNDAY
MORNING.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
DIURNAL CU DISSIPATING AS HEAT OF THE DAY HAS PASSED. LIGHT SOUTH
WINDS WILL REMAIN THROUGH THE OVERNIGHT. ANOTHER ROUND OF MVFR FOG
IS A GOOD POSSIBILITY LATE TONIGHT INTO TUESDAY MORNING. MUCH THE
SAME SCENARIO FOR TUESDAY WITH CHANCE POPS FOR SCATTERED AFTERNOON
THUNDERSTORMS AS MODELS DO SHOW A SHORTWAVE APPROACHING AFTER 21Z.
FOR NOW WILL INCLUDE VCTS FROM KPIT NORTH AND WEST IN TERMINALS.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND PASSES ACROSS THE REGION. BUILDING
HIGH PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPBZ 210140
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
940 PM EDT MON MAY 20 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TUESDAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
EVE RAOB PLOTS SHOW UPR RIDGING BLDG IN WITH DRY CONDS EXPD
OVRNGT. SKIES HAVE GONE MCLR AND THIS SHOULD CONT TNGT...ALTHOUGH
SHOULD SEE SOME CONVECTIVE DEBRIS CS MOVG IN TWD MRNG. A WARM NGT
IS EXPD WITH LOWS IN THE MID TO UPR 60S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ANOTHER DAY MUCH LIKE TODAY LOOKS TO BE IN STORE ON TUESDAY.
ALTHOUGH SOME MODEL SOLUTIONS TRACK A WEAK MID-LEVEL VORT MAXIMUM
THROUGH THE NORTHERN PORTIONS OF THE CWA EARLY IN THE DAY...THE
BEST CHANCES OF SHOWERS SHOULD GENERALLY AGAIN BE RELEGATED TO THE
AFTERNOON. DIURNAL INSTABILITY SHOULD BE A BIT MORE PRONOUNCED ON
TUESDAY AFTERNOON AS THE LOW LEVEL THERMAL RIDGE ARCHES ACROSS THE
AREA DURING THE AFTERNOON HOURS. THIS SHOULD ALLOW FOR CAPE VALUES
TO ECLIPSE 2000 J/KG PER THE NAM. WITH THAT IN MIND...SHEAR IS
ONCE AGAIN RATHER UNIMPRESSIVE...AND GIVEN THE LACK OF LARGE SCALE
FORCING DURING THE MOST UNSTABLE PORTION OF THE DAY...RELATIVELY
DISORGANIZED ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS SEEM
LIKELY DURING THE AFTERNOON.
WITH THE LOW LEVEL THERMAL RIDGE SWINGING THROUGH AND SOUNDINGS
INDICATING BETTER MIXING DURING THE AFTERNOON TUESDAY...THINGS DO
LOOK LIKELY TO HEAT UP NICELY. TEMPERATURES AT 850 MB RUN UP
TOWARD +16 TO +18C OR SO ON THE CONSENSUS...WHICH SUGGESTS HIGHS
IN THE UPPER 80S WOULD BE LIKELY. THIS IS QUITE WARM FOR THIS TIME
OF YEAR AS RECORDS ARE GENERALLY ONLY IN THE LOWER 90S FOR
TUESDAY.
AS THE SYSTEM CURRENTLY OVER THE UPPER MISSISSIPPI VALLEY FINALLY
WANDERS EASTWARD...THE WEATHER GETS MORE INTERESTING HEADING INTO
WEDNESDAY. FIRST OF ALL...A DECENT CONSENSUS ON THE FORMATION OF A
LOW LEVEL JET OVER WESTERN OHIO COULD DRIVE DISSIPATING NOCTURNAL
CONVECTION INTO SOME OF THE AREA WEDNESDAY MORNING. WHILE THIS
WOULD LIKELY INCREASE LOW LEVEL MOISTURE OVER THE
AREA...CONVECTIVE DEBRIS MAY MAKE WARMING LESS EFFICIENT ON
WEDNESDAY AND LIMIT INSTABILITY. THAT SAID...THE UPPER LEVEL
SYSTEM TRUDGING EASTWARD DOESN`T SEEM TO BRING THE BEST SYNOPTIC
FORCING INTO THE AREA UNTIL AFTER 00Z/8 PM...WHICH IS WELL PAST
THE PRIME DAYTIME INSTABILITY HOURS. HOWEVER...35-40 KTS OF 0-6 KM
SHEAR WITH CAPE VALUES IN THE 1500 J/KG RANGE ALONG WITH AN
INCOMING SHORTWAVE TROUGH AND UPPER JET RIGHT ENTRANCE REGION DO
MEAN WIDESPREAD THUNDERSTORM DEVELOPMENT IS LIKELY BY WEDNESDAY
EVENING. POPS WERE TRANSITIONED A FEW HOURS LATER IN THE FORECAST
TO SUGGEST A LATER ARRIVAL OF THE SYSTEM FOR WEDNESDAY EVENING TO
ACCOUNT FOR A BIT LATER ARRIVAL OF THE MAIN SYSTEM ITSELF.
COLDER AIR FLOODS INTO THE FORECAST AREA STARTING THURSDAY WITH
THE UPPER TROUGH AXIS NEARING. AS THIS OCCURS...WE AGAIN
DESTABILIZE DUE TO MORE RAPID MID-LEVEL COOLING RATHER THAN LOW
LEVEL WARMING. SHOWER AND THUNDERSTORM CHANCES WILL THEREFORE
CONTINUE THROUGH THURSDAY. FRIES
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A COLD FRONT MOVING SLOWLY SOUTH FROM THE GREAT LAKES WILL BRING
SHOWERS AND SCATTERED THUNDERSTORMS FOR THURSDAY NIGHT. BEHIND THE
COLD FRONT FRIDAY THE RISK OF SHOWERS WILL DIMINISH AND TEMPERATURES
WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED FOR FRIDAY NIGHT
INTO SUNDAY WITH TEMPERATURES FALLING INTO THE 40S FOR OVERNIGHT
LOWS SATURDAY AND SUNDAY MORNING.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
DIURNAL CU DISSIPATING AS HEAT OF THE DAY HAS PASSED. LIGHT SOUTH
WINDS WILL REMAIN THROUGH THE OVERNIGHT. ANOTHER ROUND OF MVFR FOG
IS A GOOD POSSIBILITY LATE TONIGHT INTO TUESDAY MORNING. MUCH THE
SAME SCENARIO FOR TUESDAY WITH CHANCE POPS FOR SCATTERED AFTERNOON
THUNDERSTORMS AS MODELS DO SHOW A SHORTWAVE APPROACHING AFTER 21Z.
FOR NOW WILL INCLUDE VCTS FROM KPIT NORTH AND WEST IN TERMINALS.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND PASSES ACROSS THE REGION. BUILDING
HIGH PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
07
000
FXUS61 KPHI 210121
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
921 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE 9-930 PM UPDATES: 630 PM FCST UPDATE ON TRACK. A QUIET NOW AND
WAITING TO SEE HOW EXTENSIVE THE FOG WILL BE.
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z NAM...THE
FCST SCENARIO TONIGHT AND TUESDAY IS BASED ON A BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. THE SECOND SMALL GROUP OF ISOLATED SHOWERS IN CUMBERLAND
COUNTY AROUND 8 PM HAS SINCE DISSIPATED.
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS. ITS SUMMERLIKE SITN SO NOT SURE HOW EXTENSIVE THE FOG BUT
WITH LIGHT WIND AND DECENT RADIATION CONDITIONS WE SHOULD SEE
AREAS OF DENSE FOG DEVELOP LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. AREAS OF LIFR FOG AND STRATUS SHOULD DEVELOP BETWEEN
05Z-09Z OVER THE COUNTRYSIDE TAF LOCATIONS AND MOVE CLOSE TO KPHL
BETWEEN 10Z-12Z. LIGHT S-SW WIND.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVES TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT THOSE SHOWERS WERE NOT INCLUDED
IN THE 18Z/20 TAFS. A LOW PROBABILITY OCCURRENCE. THAT CONVECTION
MAY NOT ARRIVE TIL AFTER DARK?
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOWERED THE SWELL A FOOT THROUGH TUESDAY BECAUSE OF A RECENT 1/2
TO 1 FT HIGH BIAS ON THE SWELL. INCREASED THE WNA4 PERIOD SLIGHTLY
TONIGHT SINCE IT WAS UNDERFCSTG BY 1-2 SECONDS.
OVERALL CAPPED SEAS AT 4 FT THROUGH 00Z WED.
THEREFORE NO HEADLINE ANTICIPATED THROUGH AT LEAST TUE AFTN.
THERE MAY BE AREAS OF FOG ON THE WATERS TONIGHT BUT DELAYED THE FOG
BECAUSE OF SW FLOW. CONFIDENCE FOR 2MI OR LESS FOG OVER THE WATER
IS BELOW AVG ON SW ISOBARIC FLOW. A SHOWERS OR TSTM IS POSSIBLE
TUE AFTERNOON BUT CONFIDENCE ON ANY QPF TUESDAY IS BELOW AVG.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 921
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG 921
MARINE...DRAG/NIERENBERG 921
CLIMATE...
000
FXUS61 KPHI 210021
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
821 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z NAM...THE
FCST SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. A NEW GROUP OF SCT SHOWERS HAS DEVELOPED OVER DE BAY AND
CUMBERLAND COUNTY 745-815PM EDT. WE JUST PROCESSED THIS AND UPDATED
THE GRIDS BUT DOES NOT READ ON THE LEGACY PRODUCTS DUE TO ITS
SHORT TERM EXISTENCE.
OTRW MODELS ARE NOW BASICALLY RAINFREE TONIGHT
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS.
SUMMERLIKE SITN SO NOT SURE HOW EXTENSIVE BUT WITH LIGHT WIND AND
DECENT RADIATION CONDITIONS WE SHOULD SEE AREAS OF DENSE FOG
DEVELOP LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR TO START. AREAS OF LIFR FOG AND STRATUS SHOULD DEVELOP
BETWEEN 05Z-09Z IN THE COUNTRYSIDE TAF LOCATIONS AND MOVE CLOSE TO
KPHL BETWEEN 10Z-12Z. LIGHT S-SW WIND.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS. THE CONVECTION MAY NOT ARRIVE TIL AFTER DARK?
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 820P
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...
000
FXUS61 KLWX 202354
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
754 PM EDT MON MAY 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE ATLANTIC WILL PROVIDE A SOUTHERLY FLOW FOR
TUESDAY AND WEDNESDAY...BRINGING WARM AND HUMID CONDITIONS.
MEANWHILE...AND UPPER LEVEL DISTURBANCE WILL CROSS THE REGION. A
COLD FRONT WILL PASS THROUGH THE AREA THURSDAY AFTERNOON AND
EVENING. COOLER CONDITIONS WILL RETURN FOR NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
ALTHO NOT QUITE AS WARM...WINDWISE IT FEELS SOMEWHAT LK MID-SUMMER
GIVEN HOW LGT THE WIND FIELD IS. CELLS WHICH PRODUCE ISOLD FLDG IN
AUGUSTA CO. IN LATE AFTN ARE BEGINNING TO WEAKEN.
ONCE DAYTIME HEATING WANES...SHRA/TSRA CVRG SHUD DIMINISH. AM
RUNNING WITH A DRY FCST OVNGT. ITS PSBL THAT THERE MAY BE A STRAY
STORM OR TWO...BUT CANNOT PINPOINT WHERE...AND WUD RATHER NOT
BLANKET LOW POPS OVER A LARGE AREA.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
MID-ATLANTIC WILL BE ON THE WARM SIDE OF THINGS DURING MID-WEEK.
THIS WILL ALLOW FOR A WARM UP TUESDAY-WEDNESDAY...WITH HIGHS IN
THE MID 80S. IF THERE IS MORE SUNSHINE...TEMPS COULD REACH UPPER
80S IN SOME LOCATIONS.
THERE WL BE TRRN CIRCULATIONS AND DIURNAL HEATING BNDRYS. HV CHC
POPS CENTERED UPON TIME OF PEAK HTG TUE AFTN. AM TAKING THAT ROUND
EWD IN THE EVNG INVOF H5 AXIS.
THE MID LVL RDG AXIS BREAKS DOWN WED WHICH WL PROVIDE ITS OWN TSRA
SUPPORT. WED AFTN POPS SEEM ADEQUATE IN THE 30-40 PCT RANGE...BUT
HV INCREASE EVNG CVRG AS HGTS FALL. NWRN CORNER OF CWFA TOUCHING
SPC DAY 3 SLGT RISK...AND ISOL SVR CRVG TO APPROX THE BLURDG IN
CONJUNCTION WITH THIS THREAT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
SLIGHT HEIGHT FALLS ARE FORECAST TOWARD THE END OF THE WEEK AS AN
UPPER TROUGH APPROACHES...IN TANDEM WITH A COLD FRONT. THERE IS SOME
QUESTION REGARDING TIMING OF THE FROPA...LATEST GUIDANCE SUGGESTING
LATE THURSDAY INTO EARLY FRIDAY. DUE TO UNCERTAINTY HAVE CHANCE POPS
IN THE THURSDAY THROUGH FRIDAY TIME FRAME...AND WE CAN FINE TUNE THE
TIMING AS WE GET CLOSER.
THERE IS GOOD AGREEMENT THAT THE FRONT WILL HAVE MOVED THROUGH THE
AREA BY THE WEEKEND...FAVORING A COOLER/DRIER AIR MASS. FORECAST
REFLECTS MOSTLY CLEAR SKIES AND TEMPERATURES NEAR CLIMATOLOGY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR CONDS PREVAIL AT ALL SITES. FOG MAY FORM AFTR MDNGT..AND HV
3SM IN SVRL OF THE TAFS..BUT GIVEN TEMPS AT SVRL SITES HAD A POST
5 PM MAX AM UNCERTAIN THIS LATE DAY WARMTH WAS FIGURED INTO THE MDLS.
EXPECT FOG/STRATUS EARLY TUESDAY AS LOW LEVEL MOISTURE REMAINS.
ONCE THIS MSTR BURNS OFF...VFR EXPECTED TO PREVAIL THE BALANCE OF
TUESDAY. CHANCE OF THUNDERSTORMS RETURNS IN THE AFTN...BUT CVRG
ISSUES REDUCE CONFIDENCE IF AIRFIELDS WL BE IMPACTED. A REPEAT
PERFORMANCE POSSIBLE WED...AND AGAIN THU. GREATEST CVRG ASSOCD
WITH CFP LT THU.
&&
.MARINE...
SLY WNDS 10-15 KT OVRNGT.
SLY WINDS ARE EXPECTED TUE-WED UNTIL A COLD FRONT MOVES THROUGH
THU SWITCHING WINDS TO THE NORTHWEST. THERES A DAILY TSRA RISK...
SPCLY IN THE AFTN/EVE.
SOUTHERLY CHANNELLING UP THE BAY COULD BRING MARGINAL SCA
CONDITIONS...PARTICULARLY DURING THE LATE AFTERNOON/EVENINGS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES REMAIN NEAR NORMAL. WILL HAVE TO WATCH SOUTHERLY
FLOW DURING THE MID-WEEK AS IT MAY SUPPORT AN INCREASE IN
DEPARTURES AGAIN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...WOODY!
PRVS...HTS
000
FXUS61 KPHI 202343
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
743 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z NAM...THE
FCST SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. WE TRIED CODING IN THE ISOLATED SHOWERS IN OCEAN COUNTY
FOR 2 HRS BUT THE LEGACY AND POINT/CLICK PRODUCTS DID NOT PICK IT
UP.
OTRW THE 630 PM UPDATE COMPLETELY WITHDREW SHOWERS FROM THE FCST.
MODELS ARE NOW BASICALLY RAINFREE TONIGHT
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS.
SUMMERLIKE SITN SO NOT SURE HOW EXTENSIVE BUT WITH LIGHT WIND AND
DECENT RADIATION CONDITIONS WE SHOULD SEE AREAS OF DENSE FOG
DEVELOP LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR TO START. AREAS OF LIFR FOG AND STRATUS SHOULD DEVELOP
BETWEEN 05Z-09Z IN THE COUNTRYSIDE TAF LOCATIONS AND MOVE CLOSE TO
KPHL BETWEEN 10Z-12Z. LIGHT S-SW WIND.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS. THE CONVECTION MAY NOT ARRIVE TIL AFTER DARK?
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 743
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG 743
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...
000
FXUS61 KPBZ 202329
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
729 PM EDT MON MAY 20 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TUESDAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
STLT/MESO DATA SHOWS AN UPR WAVE MOVG E INTO CNTRL VA. ISOLD
SHWRS/TSTMS HAVE PUSHED E OF OUR FCST AREA...SO REMOVED POPS TNGT.
SKIES SHOULD CLEAR OUT THIS EVE...BUT SOME ADDNL CONVECTIVE DEBRIS
CLOUD COVER TO THE W MAY WORK IN OVRNGT. WELL ABV AVG LOWS IN THE
60S EXPD TNGT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ANOTHER DAY MUCH LIKE TODAY LOOKS TO BE IN STORE ON TUESDAY.
ALTHOUGH SOME MODEL SOLUTIONS TRACK A WEAK MID-LEVEL VORT MAXIMUM
THROUGH THE NORTHERN PORTIONS OF THE CWA EARLY IN THE DAY...THE
BEST CHANCES OF SHOWERS SHOULD GENERALLY AGAIN BE RELEGATED TO THE
AFTERNOON. DIURNAL INSTABILITY SHOULD BE A BIT MORE PRONOUNCED ON
TUESDAY AFTERNOON AS THE LOW LEVEL THERMAL RIDGE ARCHES ACROSS THE
AREA DURING THE AFTERNOON HOURS. THIS SHOULD ALLOW FOR CAPE VALUES
TO ECLIPSE 2000 J/KG PER THE NAM. WITH THAT IN MIND...SHEAR IS
ONCE AGAIN RATHER UNIMPRESSIVE...AND GIVEN THE LACK OF LARGE SCALE
FORCING DURING THE MOST UNSTABLE PORTION OF THE DAY...RELATIVELY
DISORGANIZED ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS SEEM
LIKELY DURING THE AFTERNOON.
WITH THE LOW LEVEL THERMAL RIDGE SWINGING THROUGH AND SOUNDINGS
INDICATING BETTER MIXING DURING THE AFTERNOON TUESDAY...THINGS DO
LOOK LIKELY TO HEAT UP NICELY. TEMPERATURES AT 850 MB RUN UP
TOWARD +16 TO +18C OR SO ON THE CONSENSUS...WHICH SUGGESTS HIGHS
IN THE UPPER 80S WOULD BE LIKELY. THIS IS QUITE WARM FOR THIS TIME
OF YEAR AS RECORDS ARE GENERALLY ONLY IN THE LOWER 90S FOR
TUESDAY.
AS THE SYSTEM CURRENTLY OVER THE UPPER MISSISSIPPI VALLEY FINALLY
WANDERS EASTWARD...THE WEATHER GETS MORE INTERESTING HEADING INTO
WEDNESDAY. FIRST OF ALL...A DECENT CONSENSUS ON THE FORMATION OF A
LOW LEVEL JET OVER WESTERN OHIO COULD DRIVE DISSIPATING NOCTURNAL
CONVECTION INTO SOME OF THE AREA WEDNESDAY MORNING. WHILE THIS
WOULD LIKELY INCREASE LOW LEVEL MOISTURE OVER THE
AREA...CONVECTIVE DEBRIS MAY MAKE WARMING LESS EFFICIENT ON
WEDNESDAY AND LIMIT INSTABILITY. THAT SAID...THE UPPER LEVEL
SYSTEM TRUDGING EASTWARD DOESN`T SEEM TO BRING THE BEST SYNOPTIC
FORCING INTO THE AREA UNTIL AFTER 00Z/8 PM...WHICH IS WELL PAST
THE PRIME DAYTIME INSTABILITY HOURS. HOWEVER...35-40 KTS OF 0-6 KM
SHEAR WITH CAPE VALUES IN THE 1500 J/KG RANGE ALONG WITH AN
INCOMING SHORTWAVE TROUGH AND UPPER JET RIGHT ENTRANCE REGION DO
MEAN WIDESPREAD THUNDERSTORM DEVELOPMENT IS LIKELY BY WEDNESDAY
EVENING. POPS WERE TRANSITIONED A FEW HOURS LATER IN THE FORECAST
TO SUGGEST A LATER ARRIVAL OF THE SYSTEM FOR WEDNESDAY EVENING TO
ACCOUNT FOR A BIT LATER ARRIVAL OF THE MAIN SYSTEM ITSELF.
COLDER AIR FLOODS INTO THE FORECAST AREA STARTING THURSDAY WITH
THE UPPER TROUGH AXIS NEARING. AS THIS OCCURS...WE AGAIN
DESTABILIZE DUE TO MORE RAPID MID-LEVEL COOLING RATHER THAN LOW
LEVEL WARMING. SHOWER AND THUNDERSTORM CHANCES WILL THEREFORE
CONTINUE THROUGH THURSDAY. FRIES
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A COLD FRONT MOVING SLOWLY SOUTH FROM THE GREAT LAKES WILL BRING
SHOWERS AND SCATTERED THUNDERSTORMS FOR THURSDAY NIGHT. BEHIND THE
COLD FRONT FRIDAY THE RISK OF SHOWERS WILL DIMINISH AND TEMPERATURES
WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED FOR FRIDAY NIGHT
INTO SUNDAY WITH TEMPERATURES FALLING INTO THE 40S FOR OVERNIGHT
LOWS SATURDAY AND SUNDAY MORNING.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
DIURNAL CU DISSIPATING AS HEAT OF THE DAY HAS PASSED. LIGHT SOUTH
WINDS WILL REMAIN THROUGH THE OVERNIGHT. ANOTHER ROUND OF MVFR FOG
IS A GOOD POSSIBILITY LATE TONIGHT INTO TUESDAY MORNING. MUCH THE
SAME SCENARIO FOR TUESDAY WITH CHANCE POPS FOR SCATTERED AFTERNOON
THUNDERSTORMS AS MODELS DO SHOW A SHORTWAVE APPROACHING AFTER 21Z.
FOR NOW WILL INCLUDE VCTS FROM KPIT NORTH AND WEST IN TERMINALS.
.OUTLOOK.../TUESDAY THROUGH SATURDAY/...
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE WITH POSSIBLE
RESTRICTIONS FROM WEDNESDAY INTO THURSDAY EVENING AS A COLD FRONT
AND UPPER TROUGH APPROACHES AND PASSES ACROSS THE REGION. BUILDING
HIGH PRESSURE WILL BRING VFR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 202320
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
720 PM EDT MON MAY 20 2013
.SYNOPSIS...
THE COMBINATION OF HIGH PRESSURE OVER THE ATLANTIC AND SOUTHWEST
SURFACE WINDS WILL CONTINUE TO PULL A WARM AND HUMID AIRMASS INTO
THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE
MID ATLANTIC STATES THURSDAY NIGHT. SURFACE HIGH PRESSURE RETURNS
TO AREA FRIDAY INTO THE WEEKEND WITH DRIER CONDITIONS AND COOLER
TEMPERATURES EXPECTED.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
PULSE-TYPE CONVECTION HAS BEGUN TO WANE THIS EVENING. THERE IS
STILL ENOUGH SHORTWAVE ENERGY ALOFT AND PLENTY OF SUBTROPICAL SFC
MOISTURE AVAILABLE (IT IS BEING PULLED IN ON SW FLOW FROM THE
ATLANTIC) TO KEEP LIGHT TO MODERATE RAIN SHOWERS GOING THROUGH THE
REMAINDER OF THIS EVENING. PRECIP WILL THEN TAPER OFF OVERNIGHT.
SOUTHWEST SFC WINDS WILL STAY ABOVE 5 KT OVERNIGHT...WHICH WILL
HAMPER ANY CHANCE FOR FOG DEVELOPMENT. ANOTHER WARM AND HUMID
NIGHT AHEAD AS TEMPERATURES ONLY DROP INTO THE MID-UPPER 60S
REGIONWIDE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ON TUESDAY AND WEDNESDAY...THERE WILL BE LESS COVERAGE OF
PRECIPITATION AS UPPER LEVEL SUPPORT WEAKENS. THERE WILL STILL BE
PLENTY OF LOW LEVEL MOISTURE AND GENERALLY HAVE 30 TO 40 PERCENT
POPS ON TUESDAY DURING THE AFTERNOON AND EARLY EVENING HOURS...
DECREASING FOR THE LATE NIGHT AND MORNING HOURS. GUIDANCE ON
WEDNESDAY IS STILL UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND
KEPT 30 PERCENT POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LONG RANGE MODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU
NITE AND OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS
FEATURE. LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE
BNDRY FRI SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN.
LOWS THU NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH
TMPS A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
SOUTHERLY FLOW AND SCT SHWRS CONTINUE OVER THE AREA THIS AFTN AND
EVENG. EXPECT VFR VSBYS WITH CIGS BORDERING ON VFR/MVFR OUTSIDE OF
THE RAIN. THUNDER IS POSSIBLE AS WELL BUT NOT WIDESPREAD ENUF TO
INCLUDE IN THE TAFS ATTM. SHWRS WILL DIMINISH THIS EVENG...WITH
MVFR/IFR CIGS EXPECTED OVRNGT THRU ERLY TUE. IFR LESS LIKELY AT
ORF/ECG WHERE ONLY MVRF CONDS WERE INCLUDED IN THE TAFS.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCT SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALONG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT. HI PRES RETURNS FRI INTO THE WEEKEND.
&&
.MARINE...
NO FLAGS EXPECTED AS SRLY FLOW (AOB 15KTS WITH SEAS 2-4 FT) CONTS
ARND HIGH PRS OFF THE COAST THROUGH MID WEEK. PRS GRDNT INCRS LATE
WED AHEAD OF APPRCHG CDFRNT PROGGED TO CROSS THE AREA THURS NITE.
ANY SCA CDNTNS THAT DVLP WILL BE MARGINAL AHEAD OF SAID FRNT. WNA
CONTS TO FORECAST SEAS ARND 5 FT OUT NEAR 20 NM STARTING LATE WED
BUT WILL HOLD OFF ON ANY HEADLINE THIS FAR OUT FOR NOW.
WNDS SHFT INTO NW THEN N BEHIND FRNT FRI. NXT THREAT FOR SCA CNDTNS
COMES FRI NITE/ERLY SAT WITH A DECENT CAA SURGE XPCTD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...MAS/WRS
MARINE...MPR
000
FXUS61 KPHI 202238
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
638 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF...THE 12 AND 18Z GFS AND 18Z
NAM...THE FCST SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF
THE ECMWF/NAM SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE
AS WELL AS THE NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING. WE`VE SEEN THE ISOLATED SMALL SHOWERS IN OCEAN COUNTY AT
630 PM BUT THEY SHOULDNT LAST LONG AS THEY HEADS SEAWARD.
SO THE 630 PM UPDATE HAS COMPLETELY WITHDRAWN SHOWERS FROM THE
FCST. MODELS ARE NOW BASICALLY RAINFREE TONIGHT
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR AT LEAST PATCHY DENSE FOG AFTER MIDNIGHT. SINCE TEMP/DEWPOINTS
SPREADS AT 22Z WERE STILL LARGE...DELAYED THE FOG FORMATION ABOUT
6 HOURS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...GENERALLY VFR TO START. SOUTHWEST WIND AT 5 TO 10 KNOTS
FOR THE MOST PART EXCEPT SSE ALONG THE COASTS. VFR CONDITIONS WILL
LOWER AGAIN LATER TONIGHT IN FOG AND STRATUS AS THE HUMID AIRMASS
REMAIN IN PLACE WITH LIGHT WIND. WIDESPREAD IFR AND LIFR DEVELOPS
LATE.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG 637P
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/NIERENBERG 637P
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...
000
FXUS61 KPBZ 202201
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
601 PM EDT MON MAY 20 2013
.SYNOPSIS...
PERIODIC SHOWER AND THUNDERSTORM CHANCES WILL RETURN TUESDAY...
WITH INCREASING CHANCES WEDNESDAY AND THURSDAY AS A COLD FRONT
APPROACHES AND MOVES THROUGH. HIGH PRESSURE WILL RETURN FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
STLT/MESO DATA SHOWS AN UPR WAVE MOVG E INTO CNTRL VA. ISOLD
SHWRS/TSTMS HAVE PUSHED E OF OUR FCST AREA...SO REMOVED POPS TNGT.
SKIES SHOULD CLEAR OUT THIS EVE...BUT SOME ADDNL CONVECTIVE DEBRIS
CLOUD COVER TO THE W MAY WORK IN OVRNGT. WELL ABV AVG LOWS IN THE
60S EXPD TNGT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ANOTHER DAY MUCH LIKE TODAY LOOKS TO BE IN STORE ON TUESDAY.
ALTHOUGH SOME MODEL SOLUTIONS TRACK A WEAK MID-LEVEL VORT MAXIMUM
THROUGH THE NORTHERN PORTIONS OF THE CWA EARLY IN THE DAY...THE
BEST CHANCES OF SHOWERS SHOULD GENERALLY AGAIN BE RELEGATED TO THE
AFTERNOON. DIURNAL INSTABILITY SHOULD BE A BIT MORE PRONOUNCED ON
TUESDAY AFTERNOON AS THE LOW LEVEL THERMAL RIDGE ARCHES ACROSS THE
AREA DURING THE AFTERNOON HOURS. THIS SHOULD ALLOW FOR CAPE VALUES
TO ECLIPSE 2000 J/KG PER THE NAM. WITH THAT IN MIND...SHEAR IS
ONCE AGAIN RATHER UNIMPRESSIVE...AND GIVEN THE LACK OF LARGE SCALE
FORCING DURING THE MOST UNSTABLE PORTION OF THE DAY...RELATIVELY
DISORGANIZED ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS SEEM
LIKELY DURING THE AFTERNOON.
WITH THE LOW LEVEL THERMAL RIDGE SWINGING THROUGH AND SOUNDINGS
INDICATING BETTER MIXING DURING THE AFTERNOON TUESDAY...THINGS DO
LOOK LIKELY TO HEAT UP NICELY. TEMPERATURES AT 850 MB RUN UP
TOWARD +16 TO +18C OR SO ON THE CONSENSUS...WHICH SUGGESTS HIGHS
IN THE UPPER 80S WOULD BE LIKELY. THIS IS QUITE WARM FOR THIS TIME
OF YEAR AS RECORDS ARE GENERALLY ONLY IN THE LOWER 90S FOR
TUESDAY.
AS THE SYSTEM CURRENTLY OVER THE UPPER MISSISSIPPI VALLEY FINALLY
WANDERS EASTWARD...THE WEATHER GETS MORE INTERESTING HEADING INTO
WEDNESDAY. FIRST OF ALL...A DECENT CONSENSUS ON THE FORMATION OF A
LOW LEVEL JET OVER WESTERN OHIO COULD DRIVE DISSIPATING NOCTURNAL
CONVECTION INTO SOME OF THE AREA WEDNESDAY MORNING. WHILE THIS
WOULD LIKELY INCREASE LOW LEVEL MOISTURE OVER THE
AREA...CONVECTIVE DEBRIS MAY MAKE WARMING LESS EFFICIENT ON
WEDNESDAY AND LIMIT INSTABILITY. THAT SAID...THE UPPER LEVEL
SYSTEM TRUDGING EASTWARD DOESN`T SEEM TO BRING THE BEST SYNOPTIC
FORCING INTO THE AREA UNTIL AFTER 00Z/8 PM...WHICH IS WELL PAST
THE PRIME DAYTIME INSTABILITY HOURS. HOWEVER...35-40 KTS OF 0-6 KM
SHEAR WITH CAPE VALUES IN THE 1500 J/KG RANGE ALONG WITH AN
INCOMING SHORTWAVE TROUGH AND UPPER JET RIGHT ENTRANCE REGION DO
MEAN WIDESPREAD THUNDERSTORM DEVELOPMENT IS LIKELY BY WEDNESDAY
EVENING. POPS WERE TRANSITIONED A FEW HOURS LATER IN THE FORECAST
TO SUGGEST A LATER ARRIVAL OF THE SYSTEM FOR WEDNESDAY EVENING TO
ACCOUNT FOR A BIT LATER ARRIVAL OF THE MAIN SYSTEM ITSELF.
COLDER AIR FLOODS INTO THE FORECAST AREA STARTING THURSDAY WITH
THE UPPER TROUGH AXIS NEARING. AS THIS OCCURS...WE AGAIN
DESTABILIZE DUE TO MORE RAPID MID-LEVEL COOLING RATHER THAN LOW
LEVEL WARMING. SHOWER AND THUNDERSTORM CHANCES WILL THEREFORE
CONTINUE THROUGH THURSDAY. FRIES
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A COLD FRONT MOVING SLOWLY SOUTH FROM THE GREAT LAKES WILL BRING
SHOWERS AND SCATTERED THUNDERSTORMS FOR THURSDAY NIGHT. BEHIND THE
COLD FRONT FRIDAY THE RISK OF SHOWERS WILL DIMINISH AND TEMPERATURES
WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED FOR FRIDAY NIGHT
INTO SUNDAY WITH TEMPERATURES FALLING INTO THE 40S FOR OVERNIGHT
LOWS SATURDAY AND SUNDAY MORNING.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
BROKEN CUMULUS CEILINGS CAN BE EXPECTED THROUGH THE AFTERNOON WITH
THE HEATING OF THE DAY. CEILINGS WILL SLOWLY LIFT FROM MVFR TO VFR
BY LATE AFTERNOON. JUST A SLIGHT RISK OF A SHOWER OR ISOLATED
THUNDERSTORM INTO THIS EVENING...BUT TOO SMALL A RISK TO PUT INTO
THE TAFS. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE TONIGHT INTO
TUESDAY MORNING.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPHI 202141
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
541 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HAVING REVIEWED THE 12Z/20 ECMWF AND GFS AND 18Z NAM...THE FCST
SCENARIO TONIGHT AND TUESDAY WILL RIDE THE BLEND OF THE ECMWF/NAM
SINCE THE GFS HAS NOT DEFINED THE LOW LVL MOISTURE AS WELL AS THE
NAM/ECMWF.
ITS DOUBTFUL WHETHER ANY MORE SHOWERS WILL OCCUR IN OUR AREA THIS
EVENING AND THE 630 PM UPDATE WILL COMPLETELY CUT OUT SHOWERS FROM THE
FCST UNLESS COSPA SAYS DIFFERENTLY. COSPA AT WORST PERMITS SPRINKLES
INTO SW DE BETWEEN 7P AND 730P.
THE LACK OF MID AND UPPER LVL CLOUDINESS OVERNIGHT OPENS THE DOOR
FOR EXTENSIVE FOG AGAIN LATE TONIGHT.
THE 458 PM LEGACY PRODUCT UPDATE REDUCED THE CHANCE OF SHOWERS THIS
EVENING AND WITHDRAW THUNDER. MOVEMENT OF ACTIVITY CROSSING CHES
BAY AT 5P IS SLOWLY ENE AND NOT ENOUGH INSTABILITY IS EXPECTED TO
REMAIN BY SUNDOWN FOR THUNDER IN OUR FCST AREA.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...GENERALLY VFR TO START. SOUTHWEST WIND AT 5 TO 10 KNOTS
FOR THE MOST PART EXCEPT SSE ALONG THE COASTS. VFR CONDITIONS WILL
LOWER AGAIN TONIGHT IN FOG AND STRATUS AS THE HUMID AIRMASS REMAIN
IN PLACE WITH LIGHT WIND. WIDESPREAD IFR AND LIFR DEVELOPS LATE.
TUESDAY...IFR/LIFR CONDS IN FOG/STRATUS TO START AT 12Z IMPROVE TO
VFR SCT-BKN CLOUDS AOA 3500 FT IN THE AFTN WITH SCT AFTERNOON
SHOWERS/ISOLATED TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z/20
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.CLIMATE...
LOW PROB FIRST 90F DAY OF THE SEASON WED AFTN EXCEPTION KILG WHICH
TOUCHED 90F ON 4/10.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG/O`HARA 540P
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/GAINES/NIERENBERG/O`HARA 540P
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
CLIMATE...540P
000
FXUS61 KPHI 202104
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
504 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE THROUGH
THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE FOLLOWED BY A
HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH HOLIDAY THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
458 PM LEGACY PRODUCT UPDATE REDUCING THE CHANCE OF SHOWERS THIS
EVENING AND WITHDRAW THUNDER. MOVEMENT OF ACTIVITY CROSSING CHES
BAY AT 5P IS SLOWLY ENE AND NOT ENOUGH INSTABILITY IS EXPECTED TO
REMAIN BY SUNDOWN FOR THUNDER IN OUR FCST AREA.
THE WARM FRONT IS NOW NORTH/EAST OF THE AREA AND OUR ENTIRE CWA
IS IN THE WARM SECTOR. SEVERAL HUMID DAYS ARE AHEAD WITH OVERNIGHT
PERIODS OF LOW CLOUDS/FOG AND THEN SLOW RECOVERY THE FOLLOWING
DAY.
TONIGHT...MOSTLY CLOUDY SKIES LATE THIS AFTERNOON WILL TRANSITION
TO PARTLY CLOUDY BY SUNSET. RADIATIONAL COOLING AND THE HUMID AIR
MASS WILL LEAD TO PLENTY OF FOG AGAIN TONIGHT. A FEW SCT SHOWERS
MAY OCCUR THIS EVENING ACROSS THE DELMARVA OR SRN NJ...BUT THE
CHCS ARE RATHER LOW. OVERNIGHT LOWS WILL BE IN THE LOW 60S NORTH
AND MID 60S ACROSS THE CENTRAL AND SRN AREAS. WINDS WILL BE LIGHT
MOSTLY FROM THE S OR SW.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...GENERALLY VFR TO START. SOUTHWEST WIND AT 5 TO 10 KNOTS
FOR THE MOST PART EXCEPT SSE ALONG THE COASTS.
CONDITIONS WILL LOWER AGAIN TONIGHT IN FOG AND SOME ST AS THE HUMID
AIRMASS REMAIN IN PLACE. IF HAVE FOLLOWED THE LAMP GUIDANCE FOR THE
MOST PART WITH WIDESPREAD IFR EXPECTED AGAIN. CONDITIONS WILL AGAIN
BE SLOW TO IMPROVE TUE MORNING...BUT EVENTUALLY VFR BY AFTERNOON.
SCT AFTERNOON SHOWERS/TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z MON
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...DRAG/O`HARA 504
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...DRAG/GAINES/NIERENBERG/O`HARA 504
MARINE...DRAG/GAINES/NIERENBERG/O`HARA
000
FXUS61 KAKQ 202000
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
400 PM EDT MON MAY 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE ATLANTIC AND INTO THE CAROLINAS WILL PROVIDE
WARM AND HUMID CONDITIONS TO THE REGION THROUGH THURSDAY. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES THURSDAY NIGHT.
BEHIND THE FRONT...HIGH PRESSURE BUILDS IN FROM CANADA PROVIDING DRY
AND COOLER TEMPERATURES FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A DIFFUSE UPPER LEVEL TROUGH WAS OVER WESTERN VIRGINIA AND THE
CAROLINAS. THIS FEATURE WILL DISSIPATE BY TUESDAY AS A STRONGER
SYSTEM APPROACHES FROM THE NATIONS MID SECTION.
IN ASSOCIATION OF THE AFOREMENTIONED UPPER LEVEL TROUGH...CLUSTERS
OF THUNDERSTORMS WERE OCCURRING OVER MUCH OF THE CWA...ESPECIALLY
SOUTHERN PORTIONS. WITH WEAK DYNAMICS BUT PRECIPITABLE WATER OVER
ONE AND A HALF INCHES...THE MAIN IMPACT WILL BE LOCALLY VERY HEAVY
RAINFALL. BASED ON RECENT TRENDS...THE STRONGER THUNDERSTORMS MAY
PRODUCE GUSTY WINDS BUT BELOW SEVERE CRITERIA.
HAVE LIKELY POPS OVER ALL BUT FAR NORTHERN AREAS EARLY THIS EVENING
...SLOWLY LOWERING OVERNIGHT. POPS DECREASE FROM THE WEST TOWARD
MORNING. LOW TEMPERATURES WILL BE SIMILAR TO THE LAST FEW NIGHTS
WITH READINGS IN THE 60S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ON TUESDAY AND WEDNESDAY...THERE WILL BE LESS COVERAGE OF
PRECIPITATION AS UPPER LEVEL SUPPORT WEAKENS. THERE WILL STILL BE
PLENTY OF LOW LEVEL MOISTURE AND GENERALLY HAVE 30 TO 40 PERCENT
POPS ON TUESDAY DURING THE AFTERNOON AND EARLY EVENING HOURS...
DECREASING FOR THE LATE NIGHT AND MORNING HOURS. GUIDANCE ON
WEDNESDAY IS STILL UNCLEAR AS TO WHERE TO FOCUS PRECIPITATION AND
KEPT 30 PERCENT POPS AREA WIDE THAT AFTERNOON AND EARLY EVENING.
ON THURSDAY...UPPER LEVEL DYNAMICS INCREASE AS THE COLD FRONT OVER
THE PLAINS STATES APPROACHES THE AREA. HAVE 40-50 PERCENT POPS FOR
SHOWERS AND THUNDERSTORMS EXCEPT 30 PERCENT IN THE FAR SOUTHEAST.
NAM HAS LOWERED MAX TEMPERATURES SIGNIFICANTLY DURING THIS PERIOD
AND IS CLOSE TO EURO. LOWERED READINGS A FEW DEGREES FROM THE
PREVIOUS FORECAST WITH HIGHS LOW TO MID 80S TUESDAY...MID TO UPR 80S
WEDNESDAY AND AROUND 80 ON THURSDAY. READINGS WILL BE A BIT COOLER
NEAR THE COAST. LOWS WILL BE GENERALLY IN THE MID TO UPR 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LMODELS CONTINUE TO PUSH COLD FRONT ACROSS THE RGN THU NITE AND
OFFSHORE FRI AM. WILL KEEP THE CHC POPS WITH THIS FEATURE.
LINGERING MSTR NOW PROGGED TO SHIFT OFFSHORE WITH THE BNDRY FRI
SO WILL ONLY CARRY CHC POPS ALONG THE COAST FRI MORN. LOWS THU
NITE IN THE 60S.
CANADIAN HIGH PRES BUILDS INTO THE AREA FROM THE NW FRI AFTRN THRU
THE REST OF THE HOLIDAY WEEKEND. UPSHOT WILL BE A DRY PRD WITH TMPS
A FEW DEGREES BLO NRML.
STILL WRM FRI WITH HIGHS IN THE U70S-L80S. CAA KICKS IN FRI NITE.
LOWS THRU WEEKEND IN THE 50S. HIGHS EACH DAY L-M70S...WRMG INTO THE
M-U70S MON.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
SOUTHERLY FLOW AND SCTD SHWRS CONTINUE OVER THE AREA THIS AFTN AND
EVENG. EXPECT VFR VSBYS WITH CIGS BORDERING ON VFR/MVFR OUTSIDE OF
THE RAIN. THUNDER IS POSSIBLE AS WELL BUT NOT WIDESPREAD ENUF TO
INCLUDE IN THE TAFS ATTM. SHWRS WILL DIMINISH THIS EVENG...WITH
MVFR/IFR CIGS EXPECTED OVRNGT THRU ERLY TUE. IFR LESS LIKELY AT
ORF/ECG WHERE ONLY MVRF CONDS WERE INCLUDED IN THE TAFS.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT. HI PRES RETURNS FRI INTO THE WEEKEND.
&&
.MARINE...
NO FLAGS EXPECTED AS SRLY FLOW (AOB 15KTS WITH SEAS 2-4 FT) CONTS
ARND HIGH PRS OFF THE COAST THROUGH MID WEEK. PRS GRDNT INCRS LATE
WED AHEAD OF APPRCHG CDFRNT PROGGED TO CROSS THE AREA THURS NITE.
ANY SCA CDNTNS THAT DVLP WILL BE MARGINAL AHEAD OF SAID FRNT. WNA
CONTS TO FCTS SEAS ARND 5 FT OUT NR 20 NM STARTING LATE WED BUT WILL
HOLD OFF ON ANY HEADLINE THIS FAR OUT FOR NOW.
WNDS SHFT INTO NW THEN N BEHIND FRNT FRI. NXT THREAT FOR SCA CNDTNS
COMES FRI NITE / ERLY SAT WITH A DECENT CAA SURGE XPCTD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LSA
NEAR TERM...LSA
SHORT TERM...LSA
LONG TERM...MPR
AVIATION...MAS/WRS
MARINE...MPR
000
FXUS61 KPHI 201944
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
344 PM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY WITH HIGH PRESSURE OFFSHORE. A COLD FRONT WILL MOVE
THROUGH THE REGION THURSDAY INTO FRIDAY. THIS FRONT WILL BE
FOLLOWED BY A HIGH PRESSURE SYSTEM WHICH WILL BE IN PLACE THROUGH
HOLIDAY THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE WARM FRONT IS NOW NORTH/EAST OF THE AREA AND OUR ENTIRE CWA IS
IN THE ARM SECTOR. SEVERAL HUMID DAYS ARE AHEAD WITH OVERNIGHT
PERIODS OF LOW CLOUDS/FOG AND THEN SLOW RECOVERY THE FOLLOWING DAY.
TONIGHT...MOSTLY CLOUDY SKIES LATE THIS AFTERNOON WILL TRANSITION TO
PARTLY CLOUDY BY SUNSET. RADIATIONAL COOLING AND THE HUMID AIR MASS
WILL LEAD TO PLENTY OF FOG AGAIN TONIGHT. A FEW SCT SHOWERS MAY
OCCUR THIS EVENING ACROSS THE DELMARVA OR SRN NJ...BUT THE CHCS ARE
RATHER LOW. OVERNIGHT LOWS WILL BE IN THE LOW 60S NORTH AND MID 60S
ACROSS THE CENTRAL AND SRN AREAS. WINDS WILL BE LIGHT MOSTLY FROM
THE S OR SW.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
HIGH PRESSURE WILL REMAIN WELL OFF THE COAST...PUMPING IN WARM AND
HUMID AIR ACROSS THE REGION. A WEAK UPPER LOW WILL BE MEANDERING
ACROSS VA/MD DURING THE DAY. UPPER (H5/H7) HEIGHTS WILL BE SLOWLY
BUILDING EARLY...THEN BEGINNING TO LOWER LATE.
SLOW IMPROVEMENT IN THE CIGS/VSBYS EXPECTED TUE. AREAS OF FOG WILL
DISSIPATE BY MID MORNING AND SKIES SHOULD BECOME PARTLY SUNNY BY
AFTERNOON. THERE WILL BE MORE INSTABILITY THAN TODAY...SO A CHC FOR
SHOWERS/TSTMS WILL BE KEPT IN THE FCST FOR TUE. HIGHS WILL CLIMB
INTO THE LOW 80S NORTH AND MID 80S ACROSS THE METRO PHILADELPHIA
AREA. WINDS WILL BE SOUTHWEST AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL BE LOCATED NORTH OF THE REGION THROUGH
WEDNESDAY, WITH HIGH PRESSURE OFFSHORE. MOISTURE ADVECTION WILL
ALSO BE ABUNDANT INTO THE REGION. THIS ADVECTION, ALONG A WITH A
WARM AND MUGGY AIRMASS WILL CONTRIBUTE TO SOME INSTABILITY DURING
THE DAY WEDNESDAY. THE INSTABILITY MAY BE ON THE MAGNITUDE OF 1000
J/KG COUPLED WITH STEEP LAPSE RATES. SHEAR WILL BE VERY WEAK ON
WEDNESDAY WITH LIMITED STORM MOTIONS. PULSE TYPE CONVECTION MAY BE
POSSIBLE PARTICULARLY CLOSER TO THE FRONT DURING THE DAY. FEEL
THIS ACTIVITY WILL BE SCATTERED BUT THE DEGREE OF INSTABILITY MAY
ALLOW FOR A SCATTERED STRONG STORM. THE OVERALL LACK OF SHEAR WILL
LIMIT ANY SEVERE THREAT WEDNESDAY. WITH THE SCATTERED NATURE OF
CONVECTION HIGH TEMPERATURES MAY DIFFER IN SPOTS. HAVE GONE ON THE
WARM SIDE GIVEN THE STRONG SOUTHWEST FLOW INTO THE REGION.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY AND RIGHT NOW
THE BEST TIMING FOR FRONTAL PASSAGE IS LATER THURSDAY. AS USUAL
THIS MAY NEED TO BE ADJUSTED AS WE GET CLOSER. RAISED POPS TO HIGH
CHANCE BASED ON CURRENT TIMING. THOUGH SEVERAL OF THE GFS ENSEMBLE
MEMBERS AND THE 12Z ECMWF HINT THE FRONT MAY BE A TOUCH SLOWER
THAN MODEL FCSTS. WENT COOLER ON TEMPERATURES THURSDAY DUE TO
CLOUD COVER. THIS MAY ALSO LIMIT THE INSTABILITY POTENTIAL
THURSDAY AHEAD OF THE FRONT THOUGH SLOWER TIMING COULD LEAD TO A
MORE UNSTABLE ENVIRONMENT. OVERALL WENT WITH ELEMENTS OF THE SREF
AND WPC FOR QPF FOR THE FRONTAL PASSAGE. OVERALL, THURSDAY LOOKS
TO HAVE THE HIGHEST POPS.
BEHIND THE FRONT, STRONG HIGH PRESSURE WILL BUILD IN WITH MORE
SUNSHINE AND COOLER TEMPERATURES. HIGHS GENLY IN THE LOWER TO MID
70S, LIGHT WINDS AND SUNNY SKIES ARE LIKELY TO DOMINATE THE
HOLIDAY WEEKEND! DID NOT STRAY MUCH FROM GUIDANCE HERE. THINK THE
GFS MAY BE TO QUICK WITH ANY SYSTEM THAT COMES IN NEXT MONDAY.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE LONG SLOW CLIMB BACK TO VFR HAS CONTINUED IN MOST AREAS...A FEW
HIGH-END MVFR STILL AT 18Z. DRIER AIR HAS ARRIVED ON A SWRLY/WRLY
FLOW ALOFT...SO CONDITIONS ARE A BIT BETTER TODAY WHEN COMPARED TO
SUNDAY. WINDS HAVE BEEN SOUTHWEST AT 5 TO 10 KNOTS FOR THE MOST
PART.
CONDITIONS WILL LOWER AGAIN TONIGHT IN FOG AND SOME ST AS THE HUMID
AIRMASS REMAIN IN PLACE. IF HAVE FOLLOWED THE LAMP GUIDANCE FOR THE
MOST PART WITH WIDESPREAD IFR EXPECTED AGAIN. CONDITIONS WILL AGAIN
BE SLOW TO IMPROVE TUE MORNING...BUT EVENTUALLY VFR BY AFTERNOON.
SCT AFTERNOON SHOWERS/TSTMS POSSIBLE BUT NOT INCLUDED IN THE 18Z MON
TAFS.
OUTLOOK...
WEDNESDAY... MAINLY VFR WITH THE POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS AT ALL TAF SITES IN THE AFTERNOON TO REDUCE CONDITIONS
TO MVFR OR IFR FOR BRIEF PERIODS. SOUTHWEST WINDS 5 TO 10 KNOTS.
THURSDAY.... VFR TO MVFR IN SHOWERS AND A FEW THUNDERSTORMS.
SOUTHWEST WINDS 5 TO 15 KNOTS TURNING TO THE WEST AT NIGHT. BEST
CHC FOR SHWRS AND TSTMS THIS WEEK OCCURS THU.
FRIDAY AND SATURDAY... VFR WITH HIGH PRESSURE BUILDING IN AND WINDS
BECOMING LIGHT NORTH OR VARIABLE.
&&
.MARINE...
LOOKS LIKE THE SCA CONDITIONS ON THE OCEAN WATERS HAVE JUST ABOUT
ENDED. IT HAS BEEN A VERY LOW-END EVENT AND WITH THE WARM AIR OVER
THE COLD WATERS AND THE DECREASING P-GRADIENT...IT APPEARS THAT A
PERIOD OF SUB-SCA CONDITIONS WILL BE OVER THE WATERS. THE FLAG WILL
BE DROPPED WITH THE 330 PM CWF ISSUANCE. IT APPEARS THE THE SW WINDS
WILL CONTINUE ON THE WATERS TONIGHT THROUGH TUESDAY. THERE MAY BE
AREAS OF FOG ON THE WATERS TONIGHT AND SCAT SHOWERS/TSTMS TUE
AFTERNOON.
OUTLOOK...
SEAS AND WINDS WILL BE BELOW SCA TILL EARLY WEDNESDAY. SEAS ARE
EXPECTED TO BE AT LEAST 5 FEET FROM WEDNESDAY MORNING TILL EARLY
FRIDAY. SEAS AND WINDS WILL DECREASE FRIDAY. WIND WILL ALSO
INCREASE AS THE CDFNT APPROACHES BY THU. A SCA WILL LIKELY BE
NEEDED FOR A PORTION OF THIS TIME FRAME.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES/NIERENBERG
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...GAINES/NIERENBERG
AVIATION...GAINES/NIERENBERG/O`HARA
MARINE...GAINES/NIERENBERG/O`HARA
000
FXUS61 KPBZ 201928
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
328 PM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR WIDESPREAD
ACTIVITY ON WEDNESDAY EVENING...AS AN UPPER LEVEL DISTURBANCE
MOVES THROUGH.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
CUMULUS DEVELOPMENT THIS AFTERNOON HAS BEEN WIDESPREAD AND FAIRLY
PROLIFIC WITH EVEN THE LAST VESTIGES OF THIS MORNING`S STRATUS
OVER OHIO BEING DIFFICULT TO GET RID OF. THE COMBINATION OF AMPLE
LOW LEVEL MOISTURE...DECENT INSTABILITY...AND WEAK STEERING FLOW
HAS ALLOWED FOR ALL OF THIS TO OCCUR THROUGH THE DAY. AS THE
EVENING ENSUES...CUMULUS SHOULD GRADUALLY DISSIPATE...HOWEVER
CONVECTIVE DEBRIS CLOUDS AND REFORMATION OF SOME AREAS OF STRATUS
SEEM A DECENT BET OVERNIGHT. THIS WILL RESULT IS LESS THAN CLEAR
SKIES THROUGH THE NIGHT.
LOW LEVEL FLOW...WHILE WEAK...SHOULD CONTINUE TO BE LIGHT OUT OF
THE SOUTH OVERNIGHT. UPSTREAM DEWPOINT READINGS ARE GENERALLY IN
THE MID 60S TO NEAR 70F. WITH THIS IN MIND...AND THE LIKELIHOOD AT
LEAST SCATTERED TO BROKEN CLOUDS OVERNIGHT...LOWS SHOULD BE FAIRLY
RANGE BOUND BY THE HIGH MOISTURE CONTENT OF THE AIR MASS AND POOR
RADIATIONAL COOLING PROSPECTS. AS SUCH...LOWS DROPPING MUCH BELOW
THE MID TO UPPER 60S SEEM LIKE A BIT OF STRETCH. HAVE GENERALLY
KEPT TEMPERATURES ABOVE GUIDANCE THROUGH THE NIGHT AS A RESULT.
FRIES
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ANOTHER DAY MUCH LIKE TODAY LOOKS TO BE IN STORE ON TUESDAY.
ALTHOUGH SOME MODEL SOLUTIONS TRACK A WEAK MID-LEVEL VORT MAXIMUM
THROUGH THE NORTHERN PORTIONS OF THE CWA EARLY IN THE DAY...THE
BEST CHANCES OF SHOWERS SHOULD GENERALLY AGAIN BE RELEGATED TO THE
AFTERNOON. DIURNAL INSTABILITY SHOULD BE A BIT MORE PRONOUNCED ON
TUESDAY AFTERNOON AS THE LOW LEVEL THERMAL RIDGE ARCHES ACROSS THE
AREA DURING THE AFTERNOON HOURS. THIS SHOULD ALLOW FOR CAPE VALUES
TO ECLIPSE 2000 J/KG PER THE NAM. WITH THAT IN MIND...SHEAR IS
ONCE AGAIN RATHER UNIMPRESSIVE...AND GIVEN THE LACK OF LARGE SCALE
FORCING DURING THE MOST UNSTABLE PORTION OF THE DAY...RELATIVELY
DISORGANIZED ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS SEEM
LIKELY DURING THE AFTERNOON.
WITH THE LOW LEVEL THERMAL RIDGE SWINGING THROUGH AND SOUNDINGS
INDICATING BETTER MIXING DURING THE AFTERNOON TUESDAY...THINGS DO
LOOK LIKELY TO HEAT UP NICELY. TEMPERATURES AT 850 MB RUN UP
TOWARD +16 TO +18C OR SO ON THE CONSENSUS...WHICH SUGGESTS HIGHS
IN THE UPPER 80S WOULD BE LIKELY. THIS IS QUITE WARM FOR THIS TIME
OF YEAR AS RECORDS ARE GENERALLY ONLY IN THE LOWER 90S FOR
TUESDAY.
AS THE SYSTEM CURRENTLY OVER THE UPPER MISSISSIPPI VALLEY FINALLY
WANDERS EASTWARD...THE WEATHER GETS MORE INTERESTING HEADING INTO
WEDNESDAY. FIRST OF ALL...A DECENT CONSENSUS ON THE FORMATION OF A
LOW LEVEL JET OVER WESTERN OHIO COULD DRIVE DISSIPATING NOCTURNAL
CONVECTION INTO SOME OF THE AREA WEDNESDAY MORNING. WHILE THIS
WOULD LIKELY INCREASE LOW LEVEL MOISTURE OVER THE
AREA...CONVECTIVE DEBRIS MAY MAKE WARMING LESS EFFICIENT ON
WEDNESDAY AND LIMIT INSTABILITY. THAT SAID...THE UPPER LEVEL
SYSTEM TRUDGING EASTWARD DOESN`T SEEM TO BRING THE BEST SYNOPTIC
FORCING INTO THE AREA UNTIL AFTER 00Z/8 PM...WHICH IS WELL PAST
THE PRIME DAYTIME INSTABILITY HOURS. HOWEVER...35-40 KTS OF 0-6 KM
SHEAR WITH CAPE VALUES IN THE 1500 J/KG RANGE ALONG WITH AN
INCOMING SHORTWAVE TROUGH AND UPPER JET RIGHT ENTRANCE REGION DO
MEAN WIDESPREAD THUNDERSTORM DEVELOPMENT IS LIKELY BY WEDNESDAY
EVENING. POPS WERE TRANSITIONED A FEW HOURS LATER IN THE FORECAST
TO SUGGEST A LATER ARRIVAL OF THE SYSTEM FOR WEDNESDAY EVENING TO
ACCOUNT FOR A BIT LATER ARRIVAL OF THE MAIN SYSTEM ITSELF.
COLDER AIR FLOODS INTO THE FORECAST AREA STARTING THURSDAY WITH
THE UPPER TROUGH AXIS NEARING. AS THIS OCCURS...WE AGAIN
DESTABILIZE DUE TO MORE RAPID MID-LEVEL COOLING RATHER THAN LOW
LEVEL WARMING. SHOWER AND THUNDERSTORM CHANCES WILL THEREFORE
CONTINUE THROUGH THURSDAY. FRIES
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A COLD FRONT MOVING SLOWLY SOUTH FROM THE GREAT LAKES WILL BRING
SHOWERS AND SCATTERED THUNDERSTORMS FOR THURSDAY NIGHT. BEHIND THE
COLD FRONT FRIDAY THE RISK OF SHOWERS WILL DIMINISH AND TEMPERATURES
WILL DROP BELOW NORMAL. DRY WEATHER CAN BE EXPECTED FOR FRIDAY NIGHT
INTO SUNDAY WITH TEMPERATURES FALLING INTO THE 40S FOR OVERNIGHT
LOWS SATURDAY AND SUNDAY MORNING.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
BROKEN CUMULUS CEILINGS CAN BE EXPECTED THROUGH THE AFTERNOON WITH
THE HEATING OF THE DAY. CEILINGS WILL SLOWLY LIFT FROM MVFR TO VFR
BY LATE AFTERNOON. JUST A SLIGHT RISK OF A SHOWER OR ISOLATED
THUNDERSTORM INTO THIS EVENING...BUT TOO SMALL A RISK TO PUT INTO
THE TAFS. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE TONIGHT INTO
TUESDAY MORNING.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KLWX 201907
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
307 PM EDT MON MAY 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE ATLANTIC WILL PROVIDE A SOUTHERLY FLOW FOR
TUESDAY AND WEDNESDAY...BRINGING WARM AND HUMID CONDITIONS.
MEANWHILE...AND UPPER LEVEL DISTURBANCE WILL CROSS THE REGION. A
COLD FRONT WILL PASS THROUGH THE AREA THURSDAY AFTERNOON AND
EVENING. COOLER CONDITIONS WILL RETURN FOR NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
CWFA WITHIN WARM SECTOR TAFTN...BUT LOTSA CLDCVR HAS HELD TEMPS
DOWN...WHICH IN TURN HAS LIMITED AMT IN INSTBY GENERATED. CUTOFF
H5 TROF AXIS UNDER L/WV RDGG HAS ASSISTED IN FOCUSING SHRA/TSRA
ACTIVITY ACRS WVA/WRN VA/CENTRL NC. SINCE THESE STORMS ARE W/IN A
RDG AXIS...FWD MOTION HAS BEEN SLOW...AND MUCH OF THIS ACTIVITY
LKLY WONT REACH CWFA E OF THE SHEN VLY. GREATER INSTBY ALSO CAN BE
FOUND IN SERN VA/ERN NC DUE TO MORE AMPLE HEATING...AND SOME OF
THESE STORMS WL APPROACH SRN MD AND THE NRN NECK OF VA. POPS HIEST
IN THESE TWO AREAS. AM HANGING ONTO CHC POPS ELSW TIL ABT SUNSET.
PWAT ALMOST UP TO 1.5 INCHES...SO HVY RAIN SHUD BE THE BIGGEST
THREAT.
ONCE DAYTIME HEATING WANES...THINK SHRA/TSRA CVRG SHUD DIMINISH.
AM RUNNING WITH A DRY FCST OVNGT. ITS PSBL THAT THERE MAY BE A
STRAY STORM OR TWO...BUT CANNOT PINPOINT WHERE...AND WUD RATHER
NOT BLANKET SMALL POPS OVER A LARGE AREA. INSTEAD...THE NEARLY
SATD LLVLS SHUD LEAD TO MORE LOW CLDS/FOG FOR THE OVNGT HRS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
MID-ATLANTIC WILL RESIDE IN A WARM SECTOR DURING THE MID-WEEK. THIS
WILL ALLOW FOR A WARM UP TUESDAY THROUGH WEDNESDAY...WITH MAXIMA IN
THE MID 80S. IF THERE IS MORE SUNSHINE...THEN MAXIMA COULD EVEN
REACH UPPER 80S IN SOME LOCATIONS.
TUESDAY MORNING MAY START OFF WITH SOME FOG/STRATUS...BUT CLOUDS
SHOULD BREAK FOR SOME SUNSHINE DURING THE AFTERNOON. GREATER
INSTBY IN PLACE AND H5 TROF AXIS SHUD STILL BE LINGERING...MUCH
LIKE SSIDE VA/NC TAFTN. PLUS...THERE WL BE TRRN BASED
CIRCULATIONS AND DIURNAL HEATING BNDRYS. AM THEREFORE
UNCOMFORTABLE WITH A DRY FCST...AND HV ADDED CHC POPS CENTERED
UPON TIME OF PEAK HTG TUE AFTN. AM TAKING THAT ROUND EWD IN THE
EVNG INVOF H5 AXIS.
THE MID LVL RDG AXIS BREAKS DOWN WED WHICH WL PROVIDE ITS OWN TSRA
SUPPORT. WED AFTN POPS SEEM ADEQUATE IN THE 30-40 PCT RANGE...BUT
HV INCREASE EVNG CVRG AS HGTS FALL. NWRN CORNER OF CWFA TOUCHING
SPC DAY 3 SLGT RISK...AND ISOL SVR CRVG TO APPROX THE BLURDG IN
CONJUNCTION WITH THIS THREAT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SLIGHT HEIGHT FALLS ARE FORECAST TOWARD THE END OF THE WEEK AS AN
UPPER TROUGH APPROACHES...IN TANDEM WITH A COLD FRONT. THERE IS SOME
QUESTION REGARDING TIMING OF THE FROPA...LATEST GUIDANCE SUGGESTING
LATE THURSDAY INTO EARLY FRIDAY. DUE TO UNCERTAINTY HAVE CHANCE POPS
IN THE THURSDAY THROUGH FRIDAY TIME FRAME...AND WE CAN FINE TUNE THE
TIMING AS WE GET CLOSER.
THERE IS GOOD AGREEMENT THAT THE FRONT WILL HAVE MOVED THROUGH THE
AREA BY THE WEEKEND...FAVORING A COOLER/DRIER AIR MASS. FORECAST
REFLECTS MOSTLY CLEAR SKIES AND TEMPERATURES NEAR CLIMATOLOGY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
CIGS HV LIFTED...AND VFR CONDS PREVAIL AT ALL SITES XCPT MTN.
TSRA/SHRA CHCS THRU SUNSET SLIM...BUT NONZERO. UNLKLY THAT A CELL
WL AFFECT AN AIRFIELD...BUT CHO WL BE NEAREST AIRPORT.
EXPECT FOG/STRATUS EARLY TUESDAY AS LOW LEVEL MOISTURE REMAINS.
ONCE THIS MSTR BURNS OFF...VFR EXPECTED TO PREVAIL THE BALANCE OF
TUESDAY. CHANCE OF THUNDERSTORMS RETURNS IN THE AFTN...BUT CVRG
ISSUES REDUCE CONFIDENCE IF AIRFIELDS WL BE IMPACTED. A REPEAT
PERFORMANCE POSSIBLE WED...AND AGAIN THU. GREATEST CVRG ASSOCD
WITH CFP LT THU.
&&
.MARINE...
SLY WNDS TAFTN...BUT AOB 10 KT. THERE MAY BE A FEW SHRA/TSRA...
SPCLY IN THE MID BAY/LWR PTMC WHICH WUD PRODUCE LCLLY HIER WNDS.
SLY WINDS ARE EXPECTED TUE-WED UNTIL A COLD FRONT MOVES THROUGH
THU SWITCHING WINDS TO THE NORTHWEST. THERES A DAILY TSRA RISK...
SPCLY IN THE AFTN/EVE.
SOUTHERLY CHANNELLING UP THE BAY COULD BRING MARGINAL SCA
CONDITIONS...PARTICULARLY DURING THE LATE AFTERNOON/EVENINGS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES REMAIN NEAR NORMAL. WILL HAVE TO WATCH SOUTHERLY
FLOW DURING THE MID-WEEK AS IT MAY SUPPORT AN INCREASE IN
DEPARTURES AGAIN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
000
FXUS61 KAKQ 201800
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
200 PM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT HAS PUSHED NORTH OF THE AREA AS HIGH PRESSURE BECOMES
ANCHORED WELL OFF THE COAST. ABOVE AVERAGE TEMPERATURE WILL PREVAIL
THROUGH MUCH OF THE UPCOMING WEEK. A COLD FRONT WILL PASS THROUGH
THE MID ATLANTIC STATES LATE THURSDAY INTO EARLY FRIDAY...WITH
COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER LEVEL TROUGH CONTINUES TO OUR WEST ACROSS WESTERN VIRGINIA AND
WEST VIRGINIA AS DEPICTED WELL BY ENHANCED IR IMAGERY. SCATTERED
SHOWERS AND A FEW TSTMS EXTENDING FROM SOUTH CENTRAL VIRGINIA SOUTH
ACROSS CENTRAL NORTH CAROLINA INTO EASTERN SOUTH CAROLINA. DESPITE A
NORTHEASTWARD CELL MOVEMENT...SHOWERS HAVE TENDED TO DISSIPATE OVER
SRN VIRGINIA. AROUND 14Z...CONVECTION BEGAN TO INCREASE OVER FROM
SOUTHAMPTON COUNTY VA INTO NORTHEAST NORTH CAROLINA. SHOWERS AND
THUNDERSTORMS WILL BE MOST WIDESPREAD OVER SRN PORTIONS OF THE CWA
WITH LIKELY POPS IN PLACE. HIGH TEMPERATURES WILL BE NEAR 80 ACROSS
THE CWA EXCEPT LOW TO MID 70S NEAR THE COAST.
PRECIPITABLE WATER CONTINUES IN THE 1.5 TO 1.8 INCH RANGE SO LOCALLY
HEAVY RAINFALL WILL BE PSBL. THIS IS NOT EXPECTED TO BE WIDESPREAD
AS OMEGA IS WEAK BELOW 10K FT.
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO EARLY MONDAY EVENING
DIMINISHING TO WIDELY SCATTERED SHOWERS OVERNIGHT. PATCHY FOG WILL
BE PSBL ON THE EASTERN SHORE AND THE NORTHERN NECK. LOW TEMPERATURES
WILL BE IN THE MID TO UPR 60S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
CONDITIONS FAIRLY SIMILAR TO MONDAY WILL PERSIST TUESDAY INTO
WEDNESDAY. S/SSW WINDS WILL DRAW WARM AND MOIST AIR FROM THE
SOUTH...AND COUPLED WITH MARGINAL INSTABILITY...WILL CREATE
FAVORABLE CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT.
PRECIPITATION COVERAGE WILL WANE EACH EVENING AS THE INSTABILITY
DECREASES. TEMPERATURES ARE FORECAST TO TOP OUT IN THE MID TO UPR
80S IN MOST AREAS WITH UPR 70S TO LWR 80S NEAR THE COAST AND OVER
THE LOWER EASTERN SHORE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SOUTHERLY FLOW AND SCTD SHWRS CONTINUE OVER THE AREA THIS AFTN AND
EVENG. EXPECT VFR VSBYS WITH CIGS BORDERING ON VFR/MVFR OUTSIDE OF
THE RAIN. THUNDER IS POSSIBLE AS WELL BUT NOT WIDESPREAD ENUF TO
INCLUDE IN THE TAFS ATTM. SHWRS WILL DIMINISH THIS EVENG...WITH
MVFR/IFR CIGS EXPECTED OVRNGT THRU ERLY TUE. IFR LESS LIKELY AT
ORF/ECG WHERE ONLY MVRF CONDS WERE INCLUDED IN THE TAFS.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT. HI PRES RETURNS FRI INTO THE WEEKEND.
&&
.MARINE...
S/SSE WINDS CONTINUE ALL AREAS THIS MORNING...AS HIGH PRESSURE SFC
AND ALOFT PREVAILS OFF THE EAST COAST. THIS GENERAL PATTERN WILL
CONTINUE INTO THURSDAY. WINDS EXPECTED TO BE IN THE 10 TO 15 KT
RANGE ON THE BAY...AND AROUND 15KT ON THE OCEAN DURING MOST OF THIS
PERIOD. THUS...NO SCAS ARE ANTICIPATED THROUGH TUESDAY. CURRENT SCA
FOR SEAS ON THE NORTHERN COASTAL WATERS WILL BE ALLOWED TO EXPIRE AT
4 AM. SEAS NEAR 20 NM WILL CONTINUE TO FLIRT WITH 5
FEET...ESPECIALLY ON THE NRN COASTAL WATERS. HOWEVER...A SLOW
SUBSIDING TREND IS EXPECTED. SCTD SHWRS/TSTMS EXPECTED TODAY AND
TONIGHT...WITH A SLOW DECREASE IN COVERAGE NORTHERN AREAS ON
TUESDAY.
NEXT FRONTAL BOUNDARY WILL MOVE INTO/ACROSS THE AREA IN THE THU/FRI
TIME FRAME. LATEST GFS SUGGESTS THERE WILL BE 2 FRONTAL
PASSAGES...ONE LATE THURSDAY...THE SECOND STRONGER ONE LATE FRIDAY.
SHWRS/TSTMS EXPECTED TO ACCOMPANY BOTH FRONTS. WINDS BEHIND SECOND
BOUNDARY LIKELY TO REACH/EXCEED SCA CRITERIA FOR SEVERAL HOURS AFTER
FROPA.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB/LSA
NEAR TERM...DAP/LSA
SHORT TERM...DAP/LSA
LONG TERM...MAS
AVIATION...MAS/WRS
MARINE...WRS
000
FXUS61 KPBZ 201628
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1228 PM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR WIDESPREAD
ACTIVITY ON WEDNESDAY...AS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RELATIVELY WEAK FLOW REGIME REMAINS ENTRENCHED OVER THE FORECAST
AREA TODAY...WITH ONE WEAK SYSTEM ATTEMPTING TO MOVE DIRECTLY INTO
THE RIDGE AXIS ALONG THE EAST COAST TO OUR SOUTH AND THE MAIN
LARGE SCALE PLAYER STILL BACK OVER THE DAKOTAS TODAY. WHILE
SOUTHERLY FLOW HAS ALLOWED LOW LEVEL MOISTURE TO CREEP STEADILY
INTO THE AREA...RESULTING IN DEWPOINTS IN THE 60S THIS MORNING AND
POSSIBLY LOCALLY TOUCHING 70F IN OHIO THIS AFTERNOON...THERE IS
SEEMINGLY LITTLE TO HELP INITIATE MUCH IN THE WAY OF CONVECTION.
LARGE SCALE LIFT IS WELL OFF TO THE WEST...HOWEVER CONVECTION IS
MANAGING TO INITIATE THIS MORNING IN A LINE FROM SOUTHEASTERN
LOWER MICHIGAN INTO CENTRAL OHIO. GIVEN THE MOISTURE AND
INSTABILITY PROFILE...IT SEEMS UNLIKELY THAT THESE THUNDERSTORMS
WOULD FAIL TO PROPAGATE DOWNSTREAM A WHILE...SO POPS/THUNDER
CHANCES HAVE BEEN EXPANDED IN OHIO AND ESPECIALLY SOUTHWESTERN
PENNSYLVANIA.
DUE TO OUR POSITION RELATIVE TO THE LARGE SCALE FEATURES...MIXING
SEEMS LIKE IT SHOULD BE MOST EFFICIENT OVER THE NORTHWESTERN
PORTIONS OF THE FORECAST AREA. THIS IS CO-LOCATED WITH THE AREA OF
BEST WARM ADVECTION AT 850 MB...SO FROM ZANESVILLE TO MERCER
TEMPERATURES WERE INCREASED THIS AFTERNOON. ELSEWHERE...THE STATUS
QUO REMAINS WITH HIGHS IN THE LOWER TO MIDDLE 80S WIDESPREAD THIS
AFTERNOON. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
ANY CONVECTION THAT DEVELOPS TODAY WILL AGAIN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING.
RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY. MODELS CONTINUE TO
PROMOTE WIDESPREAD ACTIVITY LATE TONIGHT AND AGAIN TUE AFTERNOON.
THIS SEEMS TO BE OVERDONE AS THERE IS NO FORCING COMPONENT OR
UPPER LEVEL WAVE TO GET THINGS ROLLING. THINK THE BEST WAY TO
HANDLE THE SITUATION IS TO CONTINUE WITH CHANCE POPS.
EXPECT A BETTER CHANCE FOR SHOWERS AND STORMS WED AS THE RIDGE
BREAKS DOWN AS A RESULT OF LARGE SHORTWAVE TROUGH DIGGING INTO THE
UPPER MIDWEST. MORE SUBSTANTIAL WAVES WILL ROTATE AROUND THIS
FEATURE AND INTO THE UPPER OHIO VALLEY BY WED AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
BROKEN CUMULUS CEILINGS CAN BE EXPECTED THROUGH THE AFTERNOON WITH
THE HEATING OF THE DAY. CEILINGS WILL SLOWLY LIFT FROM MVFR TO VFR
BY LATE AFTERNOON. JUST A SLIGHT RISK OF A SHOWER OR ISOLATED
THUNDERSTORM INTO THIS EVENING...BUT TOO SMALL A RISK TO PUT INTO
THE TAFS. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE TONIGHT INTO
TUESDAY MORNING.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPHI 201558
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1158 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-MORNING ESTF UPDATE HAS CONTINUED THE EARLIER TRENDS OF
SLOWLY DISSIPATING FOG AND SMALL BREAKS DEVELOPING IN THE LOW
CLOUDS. A FEW WIDELY SCATTERED SHOWERS CONTINUE ACROSS THE
DELMARVA REGION...THEY ARE MOVING NORTHEAST AT A GOOD CLIP. I HAVE
UPDATED SKY/WINDS/TEMPS WITH THIS FCST. MAX TEMPS WERE HELD ABOUT
THE SAME AS BEFORE. IT COULD BE A DIFFICULT MAX FCST IS BREAKS
BECOME MORE WIDESPREAD THAT CURRENTLY EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE WARM FRONT HAS PASSED NORTH/EAST OF THE AREA. SFC WINDS ACROSS
THE SRN HALF OF THE AREA FAVOR A SWRLY/WRLY DIRECTION WHILE WINDS
ARE CALM/VRB ELSEWHERE. THE FOG CONTINUES TO SLOWLY DISSIPATE
ACROSS THE AREA. I EXPECT A SLOW RETURN TO VFR IN MANY AREAS BY
AFTERNOON. ONCE THE SUN RETURNS...THE ATMOSPHERE WILL BECOME
UNSTABLE...WITH SCT SHOWERS AND PSBL TSTMS BY MID-AFTERNOON.
OVERALL CONFID IN LOCATION OF TSTM IS LOW AND THEY ARE NOT
INCLUDED IN ANY TAF ATTM.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
THE DENSE FOG ADVISORY ACROSS THE NORTHERN NJ COASTAL WATERS HAS
BEEN ALLOWED TO EXPIRE AT NOON. LOW END SCA CONDITIONS CONTINUE.
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON/O`HARA
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON/PO
MARINE...IOVINO/ROBERTSON/PO
000
FXUS61 KAKQ 201431
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1031 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT HAS PUSHED NORTH OF THE AREA AS HIGH PRESSURE BECOMES
ANCHORED WELL OFF THE COAST. ABOVE AVERAGE TEMPERATURE WILL PREVAIL
THROUGH MUCH OF THE UPCOMING WEEK. A COLD FRONT WILL PASS THROUGH
THE MID ATLANTIC STATES LATE THURSDAY INTO EARLY FRIDAY...WITH
COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER LEVEL TROUGH CONTINUES TO OUR WEST ACROSS WESTERN VIRGINIA AND
WEST VIRGINIA AS DEPICTED WELL BY ENHANCED IR IMAGERY. SCATTERED
SHOWERS AND A FEW TSTMS EXTENDING FROM SOUTH CENTRAL VIRGINIA SOUTH
ACROSS CENTRAL NORTH CAROLINA INTO EASTERN SOUTH CAROLINA. DESPITE A
NORTHEASTWARD CELL MOVEMENT...SHOWERS HAVE TENDED TO DISSIPATE OVER
SRN VIRGINIA. AROUND 14Z...CONVECTION BEGAN TO INCREASE OVER FROM
SOUTHAMPTON COUNTY VA INTO NORTHEAST NORTH CAROLINA. SHOWERS AND
THUNDERSTORMS WILL BE MOST WIDESPREAD OVER SRN PORTIONS OF THE CWA
WITH LIKELY POPS IN PLACE. HIGH TEMPERATURES WILL BE NEAR 80 ACROSS
THE CWA EXCEPT LOW TO MID 70S NEAR THE COAST.
PRECIPITABLE WATER CONTINUES IN THE 1.5 TO 1.8 INCH RANGE SO LOCALLY
HEAVY RAINFALL WILL BE PSBL. THIS IS NOT EXPECTED TO BE WIDESPREAD
AS OMEGA IS WEAK BELOW 10K FT.
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO EARLY MONDAY EVENING
DIMINISHING TO WIDELY SCATTERED SHOWERS OVERNIGHT. PATCHY FOG WILL
BE PSBL ON THE EASTERN SHORE AND THE NORTHERN NECK. LOW TEMPERATURES
WILL BE IN THE MID TO UPR 60S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
CONDITIONS FAIRLY SIMILAR TO MONDAY WILL PERSIST TUESDAY INTO
WEDNESDAY. S/SSW WINDS WILL DRAW WARM AND MOIST AIR FROM THE
SOUTH...AND COUPLED WITH MARGINAL INSTABILITY...WILL CREATE
FAVORABLE CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT.
PRECIPITATION COVERAGE WILL WANE EACH EVENING AS THE INSTABILITY
DECREASES. TEMPERATURES ARE FORECAST TO TOP OUT IN THE MID TO UPR
80S IN MOST AREAS WITH UPR 70S TO LWR 80S NEAR THE COAST AND OVER
THE LOWER EASTERN SHORE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
IFR CONDITIONS HAVE DEVELOPED THIS MORNING FROM A KRWI TO KXSA
LINE WESTWARD. THINK THIS WILL PERSIST THROUGH 14Z-15Z...AIDED BY
AREA OF SHOWERS LIFTING NEWD OUT OF CNTRL NC. ALSO...IFR/LIFR HAS
PERSISTED SINCE 06Z AT KSBY...BUT CONDITIONS SHOULD IMPROVE BY
13Z. ELSEWHERE...VFR CONDITIONS HAVE PREVAILED OVERNIGHT.
FOR THE MOST PART...EXPECT TODAY TO BE VFR. HOWEVER...INCREASED
AMOUNT OF SUNSHINE EXPECTED TODAY SHOULD ALLOW MORE TSTMS TO DVLP
EAST OF I-95...AFFECTING KPHF/KORF/KECG DURING THE AFTERNOON
HOURS. TEMPO GROUP ADDED TO TAF. HEAVIER SHWRS/TSTMS WILL CAUSE
BRIEF IFR CONDITIONS. THINK TSTM POTENTIAL LESS AT KSBY AND...DUE
TO MORNING SHWR ACTIVITY...AT KRIC. EXPECT TONIGHT TO HAVE MAINLY
VFR/MVFR CONDITIONS...BUT POTENTIAL DOES EXIST FOR IFR TO DVLP
AFTER 07Z.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT.
&&
.MARINE...
S/SSE WINDS CONTINUE ALL AREAS THIS MORNING...AS HIGH PRESSURE SFC
AND ALOFT PREVAILS OFF THE EAST COAST. THIS GENERAL PATTERN WILL
CONTINUE INTO THURSDAY. WINDS EXPECTED TO BE IN THE 10 TO 15 KT
RANGE ON THE BAY...AND AROUND 15KT ON THE OCEAN DURING MOST OF THIS
PERIOD. THUS...NO SCAS ARE ANTICIPATED THROUGH TUESDAY. CURRENT SCA
FOR SEAS ON THE NORTHERN COASTAL WATERS WILL BE ALLOWED TO EXPIRE AT
4 AM. SEAS NEAR 20 NM WILL CONTINUE TO FLIRT WITH 5
FEET...ESPECIALLY ON THE NRN COASTAL WATERS. HOWEVER...A SLOW
SUBSIDING TREND IS EXPECTED. SCTD SHWRS/TSTMS EXPECTED TODAY AND
TONIGHT...WITH A SLOW DECREASE IN COVERAGE NORTHERN AREAS ON
TUESDAY.
NEXT FRONTAL BOUNDARY WILL MOVE INTO/ACROSS THE AREA IN THE THU/FRI
TIME FRAME. LATEST GFS SUGGESTS THERE WILL BE 2 FRONTAL
PASSAGES...ONE LATE THURSDAY...THE SECOND STRONGER ONE LATE FRIDAY.
SHWRS/TSTMS EXPECTED TO ACCOMPANY BOTH FRONTS. WINDS BEHIND SECOND
BOUNDARY LIKELY TO REACH/EXCEED SCA CRITERIA FOR SEVERAL HOURS AFTER
FROPA.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB/LSA
NEAR TERM...DAP/LSA
SHORT TERM...DAP/LSA
LONG TERM...MAS
AVIATION...WRS
MARINE...WRS
000
FXUS61 KPBZ 201427
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1027 AM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR WIDESPREAD
ACTIVITY ON WEDNESDAY...AS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RELATIVELY WEAK FLOW REGIME REMAINS ENTRENCHED OVER THE FORECAST
AREA TODAY...WITH ONE WEAK SYSTEM ATTEMPTING TO MOVE DIRECTLY INTO
THE RIDGE AXIS ALONG THE EAST COAST TO OUR SOUTH AND THE MAIN
LARGE SCALE PLAYER STILL BACK OVER THE DAKOTAS TODAY. WHILE
SOUTHERLY FLOW HAS ALLOWED LOW LEVEL MOISTURE TO CREEP STEADILY
INTO THE AREA...RESULTING IN DEWPOINTS IN THE 60S THIS MORNING AND
POSSIBLY LOCALLY TOUCHING 70F IN OHIO THIS AFTERNOON...THERE IS
SEEMINGLY LITTLE TO HELP INITIATE MUCH IN THE WAY OF CONVECTION.
LARGE SCALE LIFT IS WELL OFF TO THE WEST...HOWEVER CONVECTION IS
MANAGING TO INITIATE THIS MORNING IN A LINE FROM SOUTHEASTERN
LOWER MICHIGAN INTO CENTRAL OHIO. GIVEN THE MOISTURE AND
INSTABILITY PROFILE...IT SEEMS UNLIKELY THAT THESE THUNDERSTORMS
WOULD FAIL TO PROPAGATE DOWNSTREAM A WHILE...SO POPS/THUNDER
CHANCES HAVE BEEN EXPANDED IN OHIO AND ESPECIALLY SOUTHWESTERN
PENNSYLVANIA.
DUE TO OUR POSITION RELATIVE TO THE LARGE SCALE FEATURES...MIXING
SEEMS LIKE IT SHOULD BE MOST EFFICIENT OVER THE NORTHWESTERN
PORTIONS OF THE FORECAST AREA. THIS IS CO-LOCATED WITH THE AREA OF
BEST WARM ADVECTION AT 850 MB...SO FROM ZANESVILLE TO MERCER
TEMPERATURES WERE INCREASED THIS AFTERNOON. ELSEWHERE...THE STATUS
QUO REMAINS WITH HIGHS IN THE LOWER TO MIDDLE 80S WIDESPREAD THIS
AFTERNOON. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
ANY CONVECTION THAT DEVELOPS TODAY WILL AGAIN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING.
RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY. MODELS CONTINUE TO
PROMOTE WIDESPREAD ACTIVITY LATE TONIGHT AND AGAIN TUE AFTERNOON.
THIS SEEMS TO BE OVERDONE AS THERE IS NO FORCING COMPONENT OR
UPPER LEVEL WAVE TO GET THINGS ROLLING. THINK THE BEST WAY TO
HANDLE THE SITUATION IS TO CONTINUE WITH CHANCE POPS.
EXPECT A BETTER CHANCE FOR SHOWERS AND STORMS WED AS THE RIDGE
BREAKS DOWN AS A RESULT OF LARGE SHORTWAVE TROUGH DIGGING INTO THE
UPPER MIDWEST. MORE SUBSTANTIAL WAVES WILL ROTATE AROUND THIS
FEATURE AND INTO THE UPPER OHIO VALLEY BY WED AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
SPOTTY SHOWERS OVER THE EVENING SEEM TO HAVE DISSIPATED...SO
EXPECT THAT THE REST OF THE NIGHT WILL REMAIN DRY. IFR STRATUS IS
EXPECTED TO CONTINUE OVERNIGHT AT DUJ...ALTHOUGH THERE IS SOME
UNCERTAINTY AS TO WHETHER THE STRATUS WILL MANAGE TO PUSH ANY
FARTHER TO THE WEST. HAVE CONTINUED SCT IFR CIGS NEAR DAWN TO
ACCOUNT FOR THIS UNCERTAINTY. CONDITIONS SHOULD RETURN TO VFR AT
ALL LOCATIONS ACROSS THE REGION BY LATE MORNING. AN EXITING UPR
LVL WAVE MAY BRING A SHWR/TSTM E OF PIT BUT CONFIDENCE TOO LOW FOR
MENTION IN TAFS ATTM. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE
MONDAY NIGHT INTO TUESDAY MORNING...AND HAVE ADDED THIS IN THE 30
HOUR TAF FOR PIT.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KLWX 201427
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1027 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WARM FRONT WILL PASS THROUGH THE AREA TODAY WHILE AN UPPER-LEVEL
DISTURBANCE MOVES THROUGH THE AREA. HIGH PRESSURE OVER THE ATLANTIC
WILL PROVIDE A SOUTHERLY FLOW FOR TUESDAY THROUGH THURSDAY...
BRINGING WARM AND HUMID CONDITIONS. A COLD FRONT WILL PASS THROUGH
THE AREA LATE IN THE WEEK AND COOLER CONDITIONS WILL RETURN FOR
NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WK WMFNT ALONG OR NEAR THE PTMC RIVER THIS MRNG. LWX RAOB MOIST
BUT NOT SATD. LIKE SNDGS FM SIMLR SECTOR YDA...ITS ALSO MARGINALLY
UNSTBL. CNVCTV TEMPS UP IN THE UPR 70S...WHICH PER LAMP WUD BE
REACHABLE. IN ADDITION...AN UPR LOW MVG THRU THE TN VLY TWD WRN
VA/SRN WVA CAN BE A TRIGGERING MECHANISM.
THEREFORE...XPCT SHRA/TSRA TO DVLP TAFTN IN THE WARM AMS. PWAT
ARND 1.40 IN AND CAPE VALUES 500-1000 J/KG SUGGESTS THAT HVY
RAINERS WL BE THE BIGGER CONCERN...NOT WND GUSTS. IN FACT...SHEAR
LESS THAN 10 KT. HELD ONTO GLIMMER OF LKLY POPS FOR CENTRL VA AND
UPR PTMC HIGHLANDS...OTRW CVRG WL BE SCT AT BEST. RADAR DEPICTION
WL BE PRTLY CONTROLLED BY MESOSCALE FEATURES SUCH AS THE DIFF
HEATING BNDRY PRESENT IN SHEN VLY/PTMC HIGHLANDS ATTM.
WARM AND HUMID CONDITIONS WILL PERSIST OVERNIGHT WITH MIN TEMPS
HOLDING IN THE 60S FOR MOST AREAS. PLENTY OF MOISTURE UNDERNEATH THE
NOCTURNAL INVERSION WILL RESULT IN AREAS OF LOW CLOUDS/FOG.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
MID-ATLANTIC WILL RESIDE IN A WARM SECTOR DURING THE MID-WEEK. THIS
WILL ALLOW FOR A WARM UP TUESDAY THROUGH WEDNESDAY...WITH MAXIMA IN
THE MID 80S. IF THERE IS MORE SUNSHINE...THEN MAXIMA COULD EVEN
REACH UPPER 80S IN SOME LOCATIONS.
TUESDAY MORNING MAY START OFF WITH SOME FOG/STRATUS...BUT CLOUDS
SHOULD BREAK FOR SOME SUNSHINE DURING THE AFTERNOON. MODELS SHOW
MOISTURE IN PLACE...AND SOME INSTABILITY AS WELL HOWEVER AM HAVING
TROUBLE FINDING ANY GOOD FORCING/FOCUSING MECHANISMS FOR CONVECTION
THEREFORE CONTINUE TO FAVOR A DRY FORECAST FOR TUESDAY WITH ONLY
ISOLATED CONVECTION ACROSS THE NORTHWEST.
AIR MASS REMAINS THE SAME ON WEDNESDAY. MODELS HINT AT A BETTER
CHANCE OF DIURNAL CONVECTION SO HAVE INCLUDED CHANCE POPS IN THE
FORECAST FOR SCATTERED THUNDERSTORMS ACROSS THE CWA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SLIGHT HEIGHT FALLS ARE FORECAST TOWARD THE END OF THE WEEK AS AN
UPPER TROUGH APPROACHES...IN TANDEM WITH A COLD FRONT. THERE IS SOME
QUESTION REGARDING TIMING OF THE FROPA...LATEST GUIDANCE SUGGESTING
LATE THURSDAY INTO EARLY FRIDAY. DUE TO UNCERTAINTY HAVE CHANCE POPS
IN THE THURSDAY THROUGH FRIDAY TIME FRAME...AND WE CAN FINE TUNE THE
TIMING AS WE GET CLOSER.
THERE IS GOOD AGREEMENT THAT THE FRONT WILL HAVE MOVED THROUGH THE
AREA BY THE WEEKEND...FAVORING A COOLER/DRIER AIR MASS. FORECAST
REFLECTS MOSTLY CLEAR SKIES AND TEMPERATURES NEAR CLIMATOLOGY.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
IFR CONDS REMAIN ACROSS DCA/IAD/BWI. AT LEAST MVFR ELSW. MAY
INSOLATION WL ERODE LLVL MSTR...PERMITTING CONDITIONS TO IMPROVE
BY EARLY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED...MAINLY THIS TAFTN AND EVENING. HWVR...LOW CONFIDENCE ON
DIRECT IMPACT FOR ANY AIRFIELD.
THERE IS THE POTENTIAL FOR SOME FOG/STRATUS EARLY TUESDAY...
PARTICULARLY IF SOME OVERNIGHT CLEARING TAKES PLACE AS LOW LEVEL
MOISTURE REMAINS. BUT CONFIDENCE REMAINS ONLY LOW-MODERATE ON
OCCURRENCE ATTM. VFR EXPECTED TO PREVAIL THE BALANCE OF TUESDAY.
CHANCE OF THUNDERSTORMS RETURNS FOR WEDNESDAY AFTERNOON...AND
SHRA/TSRA REMAIN POSSIBLE UNTIL A COLD FRONT MOVES THROUGH LATE
THURSDAY INTO EARLY FRIDAY.
&&
.MARINE...
SOUTHERLY WINDS ARE EXPECTED TODAY THROUGH TONIGHT AS A WMFNT MVS
NWD. HOWEVER...WIND SPEEDS WILL REMAIN BELOW SCA CRITERIA.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED...MAINLY THIS
AFTERNOON AND EVENING.
SOUTHERLY WINDS ARE EXPECTED DURING THE MID WEEK UNTIL A COLD FRONT
MOVES THROUGH TOWARD THE END OF THE WEEK SWITCHING WINDS TO THE
NORTHWEST. SOUTHERLY FLOW CHANNELLING UP THE BAY COULD BRING
MARGINAL SCA CONDITIONS UP THE BAY PARTICULARLY DURING THE LATE
AFTERNOON/EVENINGS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES REMAIN NEAR NORMAL EARLY THIS MORNING. SOUTHERLY
WINDS ARE WILL DEVELOP OVER THE WATERS TODAY AND ANOMALIES ARE
EXPECTED TO INCREASE. HOWEVER...THE HIGH TIDE THIS AFTERNOON WILL BE
THE LOWER OF THE TWO. WILL HAVE TO WATCH SOUTHERLY FLOW DURING THE
MID-WEEK AS IT MAY SUPPORT AN INCREASE IN DEPARTURES AGAIN. BUT
CBOFS KEEPS WATER LEVELS BELOW MINOR THRESHOLDS THROUGH HIGH TIDES
TUESDAY AFTERNOON.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BJL/BPP
NEAR TERM...HTS/BJL
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...HTS/BJL/BPP
MARINE...HTS/BJL/BPP
TIDES/COASTAL FLOODING...BJL/BPP
000
FXUS61 KPHI 201335
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
935 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MID-MORNING ESTF UPDATE HAS CONTINUED THE EARLIER TRENDS OF
SLOWLY DISSIPATING FOG AND SMALL BREAKS DEVELOPING IN THE LOW
CLOUDS. A FEW WIDELY SCATTERED SHOWERS CONTINUE ACROSS THE
DELMARVA REGION...THEY ARE MOVING NORTHEAST AT A GOOD CLIP. I HAVE
UPDATED SKY/WINDS/TEMPS WITH THIS FCST. MAX TEMPS WERE HELD ABOUT
THE SAME AS BEFORE. IT COULD BE A DIFFICULT MAX FCST IS BREAKS
BECOME MORE WIDESPREAD THAT CURRENTLY EXPECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE WARM FRONT HAS PASSED NORTH/EAST OF THE AREA. SFC WINDS ACROSS
THE SRN HALF OF THE AREA FAVOR A SWRLY/WRLY DIRECTION WHILE WINDS
ARE CALM/VRB ELSEWHERE. THE FOG CONTINUES TO SLOWLY DISSIPATE
ACROSS THE AREA. I EXPECT A SLOW RETURN TO VFR IN MANY AREAS BY
AFTERNOON. ONCE THE SUN RETURNS...THE ATMOSPHERE WILL BECOME
UNSTABLE...WITH SCT SHOWERS AND PSBL TSTMS BY MID-AFTERNOON.
OVERALL CONFID IN LOCATION OF TSTM IS LOW AND THEY ARE NOT
INCLUDED IN ANY TAF ATTM.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
THE DENSE FOG ADVISORY ON THE NRN TWO NJ COASTAL WATER ZONES HAS
BEEN EXTENDED UNTIL NOON.
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ450-451.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON/O`HARA
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON/PO
MARINE...IOVINO/ROBERTSON
000
FXUS61 KPBZ 201257
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
857 AM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR WIDESPREAD
ACTIVITY ON WEDNESDAY...AS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RELATIVELY WEAK FLOW REGIME REMAINS ENTRENCHED OVER THE FORECAST
AREA TODAY...WITH ONE WEAK SYSTEM ATTEMPTING TO MOVE DIRECTLY INTO
THE RIDGE AXIS ALONG THE EAST COAST TO OUR SOUTH AND THE MAIN
LARGE SCALE PLAYER STILL BACK OVER THE DAKOTAS TODAY. WHILE
SOUTHERLY FLOW HAS ALLOWED LOW LEVEL MOISTURE TO CREEP STEADILY
INTO THE AREA...RESULTING IN DEWPOINTS IN THE 60S THIS MORNING AND
POSSIBLY LOCALLY TOUCHING 70F IN OHIO THIS AFTERNOON...THERE IS
SEEMINGLY LITTLE TO HELP INITIATE MUCH IN THE WAY OF CONVECTION.
LARGE SCALE LIFT IS WELL OFF TO THE WEST...WITH THE MODELS REALLY
ONLY HINTING AT MUCH IN THE WAY OF DAYTIME DIURNAL CONVECTION
ALONG THE SOUTHERN AND EASTERN PORTIONS OF THE AREA. GIVEN THE
MOISTURE AND INSTABILITY PROFILE...ISOLATED SHOWERS/THUNDERSTORMS
SEEM POSSIBLE IN THESE LOCATIONS...HOWEVER ANYTHING ORGANIZED
SEEMS HIGHLY UNLIKELY.
DUE TO OUR POSITION RELATIVE TO THE LARGE SCALE FEATURES...MIXING
SEEMS LIKE IT SHOULD BE MOST EFFICIENT OVER THE NORTHWESTERN
PORTIONS OF THE FORECAST AREA. THIS IS CO-LOCATED WITH THE AREA OF
BEST WARM ADVECTION AT 850 MB...SO FROM ZANESVILLE TO MERCER
TEMPERATURES WERE INCREASED THIS AFTERNOON. ELSEWHERE...THE STATUS
QUO REMAINS WITH HIGHS IN THE LOWER TO MIDDLE 80S WIDESPREAD THIS
AFTERNOON. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
ANY CONVECTION THAT DEVELOPS TODAY WILL AGAIN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING.
RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY. MODELS CONTINUE TO
PROMOTE WIDESPREAD ACTIVITY LATE TONIGHT AND AGAIN TUE AFTERNOON.
THIS SEEMS TO BE OVERDONE AS THERE IS NO FORCING COMPONENT OR
UPPER LEVEL WAVE TO GET THINGS ROLLING. THINK THE BEST WAY TO
HANDLE THE SITUATION IS TO CONTINUE WITH CHANCE POPS.
EXPECT A BETTER CHANCE FOR SHOWERS AND STORMS WED AS THE RIDGE
BREAKS DOWN AS A RESULT OF LARGE SHORTWAVE TROUGH DIGGING INTO THE
UPPER MIDWEST. MORE SUBSTANTIAL WAVES WILL ROTATE AROUND THIS
FEATURE AND INTO THE UPPER OHIO VALLEY BY WED AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
SPOTTY SHOWERS OVER THE EVENING SEEM TO HAVE DISSIPATED...SO
EXPECT THAT THE REST OF THE NIGHT WILL REMAIN DRY. IFR STRATUS IS
EXPECTED TO CONTINUE OVERNIGHT AT DUJ...ALTHOUGH THERE IS SOME
UNCERTAINTY AS TO WHETHER THE STRATUS WILL MANAGE TO PUSH ANY
FARTHER TO THE WEST. HAVE CONTINUED SCT IFR CIGS NEAR DAWN TO
ACCOUNT FOR THIS UNCERTAINTY. CONDITIONS SHOULD RETURN TO VFR AT
ALL LOCATIONS ACROSS THE REGION BY LATE MORNING. AN EXITING UPR
LVL WAVE MAY BRING A SHWR/TSTM E OF PIT BUT CONFIDENCE TOO LOW FOR
MENTION IN TAFS ATTM. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE
MONDAY NIGHT INTO TUESDAY MORNING...AND HAVE ADDED THIS IN THE 30
HOUR TAF FOR PIT.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPHI 201206
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
806 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE DENSE FOG...IN MOST AREAS...HAS THINNED AND VSBYS HAVE
INCREASED ABOVE A MILE IN MANY AREAS. WE HAVE DECIDED TO CANCEL
THE DENSE FOG ADVISORY FOR NOW...WITH THE CAVEAT THAT THERE WILL
STILL BE A FEW AREAS OF THICKER FOG FOR THE NEXT FEW HOURS. SKIES
WILL GRADUALLY BECOME PARTLY SUNNY BY NOON. A FEW SHOWERS WILL
AFFECT SRN DEL IN A FEW HOURS WITH SMALL CHC POPS INSERTED IN THE
GRIDS/WORDS.
ONCE THE REMAINDER FOG LIFTS, CLOUDS MAY BEGIN TO BREAK SOME THIS
AFTERNOON, WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE SOME. A
WEAK DISTURBANCE ALOFT IS EXPECTED TO CROSS THE AREA LATER TODAY,
AND WITH AMPLE LOW-LEVEL MOISTURE AND INSTABILITY, SCATTERED
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TO DEVELOP.
WE HAVE NOT MADE ANY TEMPERATURE CHANGES TO THE FCST AT THIS
POINT, THE MET/MAV MOS NUMBERS FROM BEFORE STILL LOOK GOOD.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
IFR CONDITIONS PREVAIL ACROSS ALL TAF SITES EARLY THIS MORNING.
CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE THIS MORNING AS A
FRONTAL BOUNDARY SLOWLY LIFTS ACROSS THE AREA. SITES ARE EXPECTED
TO BECOME MVFR/VFR BY LATE MORNING/EARLY AFTERNOON. SCATTERED
SHOWERS AND A FEW ISOLATED THUNDERSTORMS ARE POSSIBLE TODAY,
ESPECIALLY THIS AFTERNOON. CONFIDENCE IN THUNDERSTORMS OCCURRING
IS LOW, SO THEY WERE NOT INCLUDED IN THE TAFS. WINDS THIS MORNING
WILL VARY FROM MORE OF AN EASTERLY DIRECTION NORTH OF THE FRONTAL
BOUNDARY, TO MORE SOUTHERLY SOUTH OF THE BOUNDARY. WINDS WILL
BECOME MORE SOUTH-SOUTHWESTERLY EVERYWHERE LATER THIS MORNING AND
THIS AFTERNOON.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
THE DENSE FOG ADVISORY ON THE NRN TWO NJ COASTAL WATER ZONES HAS
BEEN EXTENDED UNTIL NOON.
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ450-451.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...PO/ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON
MARINE...IOVINO/ROBERTSON
000
FXUS61 KAKQ 201052
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
652 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT HAS PUSHED NORTH OF THE AREA WHILE HIGH PRESSURE BECOMES
ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS WILL BECOME
MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
FAIRLY WEAK FRONTAL BOUNDARY...IS NOW TO THE N OF THE CWA CAUSING
SFC WINDS TO BE GENERALLY FROM THE SOUTH. INCREASED POPS FOR
WESTERN AND CENTRAL PORTIONS OF THE CWA DUE TO INCREASED SHOWER
ACTIVITY VISIBLE ON RADAR...DO NOT EXPECT ANY THUNDER THROUGH THE
MORNING HOURS BUT WITH PWATS ~1.5IN...EXPECT MODERATE RAINFALL TO
OCCUR DURING ANY SHOWERS...GREATLY REDUCING VISIBILITIES.
SOME PATCHY FOG HAS DEVELOP ONCE AGAIN MONDAY MORNING...
ESPECIALLY IN AREAS NORTH OF INTERSTATE 64. WIDESPREAD DENSE FOG
IS NOT ANTICIPATED AS THE FOG SHOULD MAINLY DEVELOP FROM LOWERING
STRATUS.
EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP MONDAY
AFTN...LASTING THROUGH THE EVENING HOURS. DEW POINTS WELL INTO THE
60S WITH TEMPS RISING TO ~80 ALONG WITH MODERATE INSTABILITY WILL
FUEL THE DEVELOPMENT OF THESE STORMS. BUT...DUE TO RATHER WEAK
WIND SHEAR...NOT EXPECTING ANY SEVERE THUNDERSTORMS. NAM BUFR
SOUNDING INDICATING PWATS WILL AGAIN BE HIGH...RANGING FROM
1.60-1.75IN. WITH THAT IN MIND...ANY STORMS THAT DEVELOP WILL HAVE
HEAVY RAINFALL...CAUSING REDUCED VISIBILITIES AND HAZARDOUS
DRIVING CONDITIONS.
HIGH TEMPERATURES FOR MONDAY ARE EXPECTED TO BE NEAR 80 ACROSS THE
CWA...WHILE SLIGHTLY COOLER NEAR THE COAST.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
CONDITIONS FAIRLY SIMILAR TO MONDAY WILL PERSIST TUESDAY INTO
WEDNESDAY. S/SSW WINDS WILL DRAW WARM AND MOIST AIR FROM THE
SOUTH...AND COUPLED WITH MARGINAL INSTABILITY...WILL CREATE
FAVORABLE CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT.
PRECIPITATION COVERAGE WILL WANE EACH EVENING AS THE INSTABILITY
DECREASES. TEMPERATURES ARE FORECAST TO TOP OUT IN THE MID TO UPR
80S IN MOST AREAS WITH UPR 70S TO LWR 80S NEAR THE COAST AND OVER
THE LOWER EASTERN SHORE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
IFR CONDITIONS HAVE DEVELOPED THIS MORNING FROM A KRWI TO KXSA
LINE WESTWARD. THINK THIS WILL PERSIST THROUGH 14Z-15Z...AIDED BY
AREA OF SHOWERS LIFTING NEWD OUT OF CNTRL NC. ALSO...IFR/LIFR HAS
PERSISTED SINCE 06Z AT KSBY...BUT CONDITIONS SHOULD IMPROVE BY
13Z. ELSEWHERE...VFR CONDITIONS HAVE PREVAILED OVERNIGHT.
FOR THE MOST PART...EXPECT TODAY TO BE VFR. HOWEVER...INCREASED
AMOUNT OF SUNSHINE EXPECTED TODAY SHOULD ALLOW MORE TSTMS TO DVLP
EAST OF I-95...AFFECTING KPHF/KORF/KECG DURING THE AFTERNOON
HOURS. TEMPO GROUP ADDED TO TAF. HEAVIER SHWRS/TSTMS WILL CAUSE
BRIEF IFR CONDITIONS. THINK TSTM POTENTIAL LESS AT KSBY AND...DUE
TO MORNING SHWR ACTIVITY...AT KRIC. EXPECT TONIGHT TO HAVE MAINLY
VFR/MVFR CONDITIONS...BUT POTENTIAL DOES EXIST FOR IFR TO DVLP
AFTER 07Z.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT.
&&
.MARINE...
S/SSE WINDS CONTINUE ALL AREAS THIS MORNING...AS HIGH PRESSURE SFC
AND ALOFT PREVAILS OFF THE EAST COAST. THIS GENERAL PATTERN WILL
CONTINUE INTO THURSDAY. WINDS EXPECTED TO BE IN THE 10 TO 15 KT
RANGE ON THE BAY...AND AROUND 15KT ON THE OCEAN DURING MOST OF THIS
PERIOD. THUS...NO SCAS ARE ANTICIPATED THROUGH TUESDAY. CURRENT SCA
FOR SEAS ON THE NORTHERN COASTAL WATERS WILL BE ALLOWED TO EXPIRE AT
4 AM. SEAS NEAR 20 NM WILL CONTINUE TO FLIRT WITH 5
FEET...ESPECIALLY ON THE NRN COASTAL WATERS. HOWEVER...A SLOW
SUBSIDING TREND IS EXPECTED. SCTD SHWRS/TSTMS EXPECTED TODAY AND
TONIGHT...WITH A SLOW DECREASE IN COVERAGE NORTHERN AREAS ON
TUESDAY.
NEXT FRONTAL BOUNDARY WILL MOVE INTO/ACROSS THE AREA IN THE THU/FRI
TIME FRAME. LATEST GFS SUGGESTS THERE WILL BE 2 FRONTAL
PASSAGES...ONE LATE THURSDAY...THE SECOND STRONGER ONE LATE FRIDAY.
SHWRS/TSTMS EXPECTED TO ACCOMPANY BOTH FRONTS. WINDS BEHIND SECOND
BOUNDARY LIKELY TO REACH/EXCEED SCA CRITERIA FOR SEVERAL HOURS AFTER
FROPA.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...DAP
SHORT TERM...DAP/LSA
LONG TERM...JEF
AVIATION...WRS
MARINE...WRS
HYDROLOGY...
000
FXUS61 KAKQ 201026
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
626 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT HAS PUSHED NORTH OF THE AREA WHILE HIGH PRESSURE BECOMES
ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS WILL BECOME
MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
FAIRLY WEAK FRONTAL BOUNDARY...IS NOW TO THE N OF THE CWA CAUSING
SFC WINDS TO BE GENERALLY FROM THE SOUTH. INCREASED POPS FOR
WESTERN AND CENTRAL PORTIONS OF THE CWA DUE TO INCREASED SHOWER
ACTIVITY VISIBLE ON RADAR...DO NOT EXPECT ANY THUNDER THROUGH THE
MORNING HOURS BUT WITH PWATS ~1.5IN...EXPECT MODERATE RAINFALL TO
OCCUR DURING ANY SHOWERS...GREATLY REDUCING VISIBILITIES.
SOME PATCHY FOG HAS DEVELOP ONCE AGAIN MONDAY MORNING...
ESPECIALLY IN AREAS NORTH OF INTERSTATE 64. WIDESPREAD DENSE FOG
IS NOT ANTICIPATED AS THE FOG SHOULD MAINLY DEVELOP FROM LOWERING
STRATUS.
EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP MONDAY
AFTN...LASTING THROUGH THE EVENING HOURS. DEW POINTS WELL INTO THE
60S WITH TEMPS RISING TO ~80 ALONG WITH MODERATE INSTABILITY WILL
FUEL THE DEVELOPMENT OF THESE STORMS. BUT...DUE TO RATHER WEAK
WIND SHEAR...NOT EXPECTING ANY SEVERE THUNDERSTORMS. NAM BUFR
SOUNDING INDICATING PWATS WILL AGAIN BE HIGH...RANGING FROM
1.60-1.75IN. WITH THAT IN MIND...ANY STORMS THAT DEVELOP WILL HAVE
HEAVY RAINFALL...CAUSING REDUCED VISIBILITIES AND HAZARDOUS
DRIVING CONDITIONS.
HIGH TEMPERATURES FOR MONDAY ARE EXPECTED TO BE NEAR 80 ACROSS THE
CWA...WHILE SLIGHTLY COOLER NEAR THE COAST.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
CONDITIONS FAIRLY SIMILAR TO MONDAY WILL PERSIST TUESDAY INTO
WEDNESDAY. S/SSW WINDS WILL DRAW WARM AND MOIST AIR FROM THE
SOUTH...AND COUPLED WITH MARGINAL INSTABILITY...WILL CREATE
FAVORABLE CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT.
PRECIPITATION COVERAGE WILL WANE EACH EVENING AS THE INSTABILITY
DECREASES. TEMPERATURES ARE FORECAST TO TOP OUT IN THE MID TO UPR
80S IN MOST AREAS WITH UPR 70S TO LWR 80S NEAR THE COAST AND OVER
THE LOWER EASTERN SHORE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
CONSIDERABLY LESS STRATUS/FOG ACROSS THE AREA AND TERMINALS
TONIGHT VS. LAST NIGHT. MAIN AREA OF POTENTIAL IFR CONDITIONS
APPEARS TO BE ON THE DELMARVA. HAVE KSBY IN IFR THE NEXT 6
HOURS...BASED UPON OBSERVATION TRENDS AT KOXB/KWAL AND KGED.
ELSEWHERE...EXPECT SOME BR...AND PERHAPS SOME STRATUS
DEVELOPMENT...BUT GENERALLY VFR/MVFR CONDITIONS EXPECTED.
INCREASED LO LVL MIXING VICE LAST NIGHT ALSO EXPECTED TO INHIBIT
FOG DEVELOPMENT BEFORE SUNRISE. COULD BE A FEW SHWRS AS
WELL...BUT HAVE LEFT OUT OF MOST TERMINALS DUE TO LACK OF
DEFINITIVE TIMING.
FOR THE MOST PART...EXPECT TODAY TO BE VFR. HOWEVER...SIGNIFICANT
UNCERTAINTY EXISTS WITH REGARD TO POTENTIAL SHWR/TSTM ACTIVITY.
GIVEN INCREASED AMOUNT OF SUNSHINE EXPECTED TODAY...HAVE OPTED TO
INCLUDE PROB30 FOR TSTMS AT MOST TERMINALS IN THE 19Z TO 23Z TIME
FRAME. HEAVIER SHWRS/TSTMS WILL CAUSE BRIEF IFR CONDITIONS. EXPECT
TONIGHT TO BE SIMILAR TO CURRENT CONDITIONS...WITH MAINLY VFR/MVFR
CONDITIONS PREVAILING.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT.
&&
.MARINE...
S/SSE WINDS CONTINUE ALL AREAS THIS MORNING...AS HIGH PRESSURE SFC
AND ALOFT PREVAILS OFF THE EAST COAST. THIS GENERAL PATTERN WILL
CONTINUE INTO THURSDAY. WINDS EXPECTED TO BE IN THE 10 TO 15 KT
RANGE ON THE BAY...AND AROUND 15KT ON THE OCEAN DURING MOST OF THIS
PERIOD. THUS...NO SCAS ARE ANTICIPATED THROUGH TUESDAY. CURRENT SCA
FOR SEAS ON THE NORTHERN COASTAL WATERS WILL BE ALLOWED TO EXPIRE AT
4 AM. SEAS NEAR 20 NM WILL CONTINUE TO FLIRT WITH 5
FEET...ESPECIALLY ON THE NRN COASTAL WATERS. HOWEVER...A SLOW
SUBSIDING TREND IS EXPECTED. SCTD SHWRS/TSTMS EXPECTED TODAY AND
TONIGHT...WITH A SLOW DECREASE IN COVERAGE NORTHERN AREAS ON
TUESDAY.
NEXT FRONTAL BOUNDARY WILL MOVE INTO/ACROSS THE AREA IN THE THU/FRI
TIME FRAME. LATEST GFS SUGGESTS THERE WILL BE 2 FRONTAL
PASSAGES...ONE LATE THURSDAY...THE SECOND STRONGER ONE LATE FRIDAY.
SHWRS/TSTMS EXPECTED TO ACCOMPANY BOTH FRONTS. WINDS BEHIND SECOND
BOUNDARY LIKELY TO REACH/EXCEED SCA CRITERIA FOR SEVERAL HOURS AFTER
FROPA.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...DAP
SHORT TERM...DAP/LSA
LONG TERM...JEF
AVIATION...WRS
MARINE...WRS
HYDROLOGY...
000
FXUS61 KPBZ 200818
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
418 AM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR WIDESPREAD
ACTIVITY ON WEDNESDAY...AS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REALLY VERY LITTLE CHANGE IN THE WEATHER TODAY...TO THAT WHICH WE
SAW OVER THE PAST WEEKEND. EASTERN U.S. RIDGE REMAINS IN PLACE
WITH WAVES OF ENERGY MOVING THROUGH THE MID-ATLANTIC REGION.
MODELS ARE HINTING THAT A PIECE OF ENERGY MAY BREAK FROM THE MAIN
WAVE AND MOVE TOWARD MY SOUTHERN ZONES THIS AFTERNOON. THIS COULD
BE ENOUGH TO SPARK A SHOWER OR STORM ACROSS THE SOUTH.
THE ATMOSPHERE WILL BE PLENTY UNSTABLE TODAY...HOWEVER STRONG WAA
ALOFT WILL PROVIDE A CAP...PREVENTING MORE WIDESPREAD CONVECTION
FROM DEVELOPING. ADDITIONALLY...THE 50H RIDGE WILL STRENGTHEN
THIS AFTERNOON INCREASING THE OVERALL SUBSIDENCE.
OVER THE WEEKEND...THE NAM AND GFS HAD BOTH DONE WELL WITH HIGH
TEMPS...SO WILL LEAN CLOSE ON THESE NUMBERS FOR THE FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
ANY CONVECTION THAT DEVELOPS TODAY WILL AGAIN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING.
RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY. MODELS CONTINUE TO
PROMOTE WIDESPREAD ACTIVITY LATE TONIGHT AND AGAIN TUE AFTERNOON.
THIS SEEMS TO BE OVERDONE AS THERE IS NO FORCING COMPONENT OR
UPPER LEVEL WAVE TO GET THINGS ROLLING. THINK THE BEST WAY TO
HANDLE THE SITUATION IS TO CONTINUE WITH CHANCE POPS.
EXPECT A BETTER CHANCE FOR SHOWERS AND STORMS WED AS THE RIDGE
BREAKS DOWN AS A RESULT OF LARGE SHORTWAVE TROUGH DIGGING INTO THE
UPPER MIDWEST. MORE SUBSTANTIAL WAVES WILL ROTATE AROUND THIS
FEATURE AND INTO THE UPPER OHIO VALLEY BY WED AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
SPOTTY SHOWERS OVER THE EVENING SEEM TO HAVE DISSIPATED...SO
EXPECT THAT THE REST OF THE NIGHT WILL REMAIN DRY. IFR STRATUS IS
EXPECTED TO CONTINUE OVERNIGHT AT DUJ...ALTHOUGH THERE IS SOME
UNCERTAINTY AS TO WHETHER THE STRATUS WILL MANAGE TO PUSH ANY
FARTHER TO THE WEST. HAVE CONTINUED SCT IFR CIGS NEAR DAWN TO
ACCOUNT FOR THIS UNCERTAINTY. CONDITIONS SHOULD RETURN TO VFR AT
ALL LOCATIONS ACROSS THE REGION BY LATE MORNING. AN EXITING UPR
LVL WAVE MAY BRING A SHWR/TSTM E OF PIT BUT CONFIDENCE TOO LOW FOR
MENTION IN TAFS ATTM. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE
MONDAY NIGHT INTO TUESDAY MORNING...AND HAVE ADDED THIS IN THE 30
HOUR TAF FOR PIT.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 200813
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
413 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT HAS PUSHED NORTH OF THE AREA WHILE HIGH PRESSURE BECOMES
ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS WILL BECOME
MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
FAIRLY WEAK FRONTAL BOUNDARY...IS NOW TO THE N OF THE CWA CAUSING
SFC WINDS TO BE GENERALLY FROM THE SOUTH. INCREASED POPS FOR
WESTERN AND CENTRAL PORTIONS OF THE CWA DUE TO INCREASED SHOWER
ACTIVITY VISIBLE ON RADAR...DO NOT EXPECT ANY THUNDER THROUGH THE
MORNING HOURS BUT WITH PWATS ~1.5IN...EXPECT MODERATE RAINFALL TO
OCCUR DURING ANY SHOWERS...GREATLY REDUCING VISIBILITIES.
SOME PATCHY FOG IS EXPECTED TO DEVELOP ONCE AGAIN EARLY MONDAY
MORNING... ESPECIALLY IN AREAS NORTH OF INTERSTATE 64 AND ON THE
MARYLAND EASTERN SHORE. WIDESPREAD DENSE FOG IS NOT ANTICIPATED AS
THE FOG SHOULD MAINLY DEVELOP FROM LOWERING STRATUS.
EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP MONDAY AFTN...LASTING
THROUGH THE EVENING HOURS. DEW POINTS WELL INTO THE 60S WITH TEMPS
RISING TO ~80 ALONG WITH MODERATE INSTABILITY WILL FUEL THE
DEVELOPMENT OF THESE STORMS. BUT...DUE TO RATHER WEAK WIND
SHEAR...NOT EXPECTING ANY SEVERE THUNDERSTORMS. NAM BUFR SOUNDING
INDICATING PWATS WILL AGAIN BE HIGH...RANGING FROM 1.60-1.75IN. WITH
THAT IN MIND...ANY STORMS THAT DEVELOP WILL HAVE HEAVY
RAINFALL...CAUSING REDUCED VISIBILITIES AND HAZARDOUS DRIVING
CONDITIONS.
HIGH TEMPERATURES FOR MONDAY ARE EXPECTED TO BE NEAR 80 ACROSS THE
CWA...WHILE SLIGHTLY COOLER NEAR THE COAST.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
CONDITIONS FAIRLY SIMILAR TO MONDAY WILL PERSIST TUESDAY INTO
WEDNESDAY. S/SSW WINDS WILL DRAW WARM AND MOIST AIR FROM THE
SOUTH...AND COUPLED WITH MARGINAL INSTABILITY...WILL CREATE
FAVORABLE CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT.
PRECIPITATION COVERAGE WILL WANE EACH EVENING AS THE INSTABILITY
DECREASES. TEMPERATURES ARE FORECAST TO TOP OUT IN THE MID TO UPR
80S IN MOST AREAS WITH UPR 70S TO LWR 80S NEAR THE COAST AND OVER
THE LOWER EASTERN SHORE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
CONSIDERABLY LESS STRATUS/FOG ACROSS THE AREA AND TERMINALS
TONIGHT VS. LAST NIGHT. MAIN AREA OF POTENTIAL IFR CONDITIONS
APPEARS TO BE ON THE DELMARVA. HAVE KSBY IN IFR THE NEXT 6
HOURS...BASED UPON OBSERVATION TRENDS AT KOXB/KWAL AND KGED.
ELSEWHERE...EXPECT SOME BR...AND PERHAPS SOME STRATUS
DEVELOPMENT...BUT GENERALLY VFR/MVFR CONDITIONS EXPECTED.
INCREASED LO LVL MIXING VICE LAST NIGHT ALSO EXPECTED TO INHIBIT
FOG DEVELOPMENT BEFORE SUNRISE. COULD BE A FEW SHWRS AS
WELL...BUT HAVE LEFT OUT OF MOST TERMINALS DUE TO LACK OF
DEFINITIVE TIMING.
FOR THE MOST PART...EXPECT TODAY TO BE VFR. HOWEVER...SIGNIFICANT
UNCERTAINTY EXISTS WITH REGARD TO POTENTIAL SHWR/TSTM ACTIVITY.
GIVEN INCREASED AMOUNT OF SUNSHINE EXPECTED TODAY...HAVE OPTED TO
INCLUDE PROB30 FOR TSTMS AT MOST TERMINALS IN THE 19Z TO 23Z TIME
FRAME. HEAVIER SHWRS/TSTMS WILL CAUSE BRIEF IFR CONDITIONS. EXPECT
TONIGHT TO BE SIMILAR TO CURRENT CONDITIONS...WITH MAINLY VFR/MVFR
CONDITIONS PREVAILING.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT.
&&
.MARINE...
S/SSE WINDS CONTINUE ALL AREAS THIS MORNING...AS HIGH PRESSURE SFC
AND ALOFT PREVAILS OFF THE EAST COAST. THIS GENERAL PATTERN WILL
CONTINUE INTO THURSDAY. WINDS EXPECTED TO BE IN THE 10 TO 15 KT
RANGE ON THE BAY...AND AROUND 15KT ON THE OCEAN DURING MOST OF THIS
PERIOD. THUS...NO SCAS ARE ANTICIPATED THROUGH TUESDAY. CURRENT SCA
FOR SEAS ON THE NORTHERN COASTAL WATERS WILL BE ALLOWED TO EXPIRE AT
4 AM. SEAS NEAR 20 NM WILL CONTINUE TO FLIRT WITH 5
FEET...ESPECIALLY ON THE NRN COASTAL WATERS. HOWEVER...A SLOW
SUBSIDING TREND IS EXPECTED. SCTD SHWRS/TSTMS EXPECTED TODAY AND
TONIGHT...WITH A SLOW DECREASE IN COVERAGE NORTHERN AREAS ON
TUESDAY.
NEXT FRONTAL BOUNDARY WILL MOVE INTO/ACROSS THE AREA IN THE THU/FRI
TIME FRAME. LATEST GFS SUGGESTS THERE WILL BE 2 FRONTAL
PASSAGES...ONE LATE THURSDAY...THE SECOND STRONGER ONE LATE FRIDAY.
SHWRS/TSTMS EXPECTED TO ACCOMPANY BOTH FRONTS. WINDS BEHIND SECOND
BOUNDARY LIKELY TO REACH/EXCEED SCA CRITERIA FOR SEVERAL HOURS AFTER
FROPA.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...DAP
SHORT TERM...DAP/LSA
LONG TERM...JEF
AVIATION...WRS
MARINE...WRS
HYDROLOGY...
000
FXUS61 KPHI 200808
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
408 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDED FROM THE GREAT LAKES TO THE WATERS
OFF THE MIDDLE ATLANTIC COAST EARLY THIS MORNING. THE BOUNDARY IS
EXPECTED TO WEAKEN AND DISSIPATE TODAY. MEANWHILE, ANOTHER FRONTAL
BOUNDARY FROM THE NORTH IS FORECAST TO DROP INTO NEW YORK AND NEW
ENGLAND. THE FRONT IS EXPECTED TO STALL ACROSS THAT AREA FOR
TONIGHT AND TUESDAY BEFORE LIFTING BACK TO THE NORTH. A COLD FRONT
IS FORECAST TO APPROACH FROM THE WEST ON THURSDAY AND IT SHOULD
PASS THROUGH OUR REGION ON THURSDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE TO OUR EAST ACROSS THE ATLANTIC OCEAN WILL CONTINUE
TO SLIDE TO THE SOUTH AND EAST TODAY. A FRONTAL BOUNDARY WAS
DRAPED ACROSS SOUTHERN NEW JERSEY AND CENTRAL DELMARVA EARLY THIS
MORNING. THE FRONT IS EXPECTED TO SLOWLY MOVE NORTHWARD THIS
MORNING, AND MAY END UP WASHING OUT AS IT LIFTS THROUGH THE AREA.
AREAS OF DENSE FOG WILL REMAIN ACROSS THE AREA NORTH OF THE SLOW
MOVING FRONTAL BOUNDARY, SO THE DENSE FOG ADVISORY REMAINS THROUGH
8 AM. AS THIS BOUNDARY LIFTS ACROSS THE AREA, THE FOG WILL
DISSIPATE SOME BEHIND THE BOUNDARY. EVEN IF THE BOUNDARY HAPPENS
TO DISSIPATE ACROSS THE AREA, FOG SHOULD BEGIN TO DISSIPATE BY
LATE MORNING.
ONCE THE FOG LIFTS, CLOUDS MAY BEGIN TO BREAK SOME THIS
AFTERNOON, WHICH WILL ALLOW THE ATMOSPHERE TO DESTABILIZE SOME. A
WEAK DISTURBANCE ALOFT IS EXPECTED TO CROSS THE AREA LATER TODAY,
AND WITH AMPLE LOW-LEVEL MOISTURE AND INSTABILITY, SCATTERED
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TO DEVELOP.
MAV/MET MOS NUMBERS WERE SIMILAR, SO A BLEND OF THE GUIDANCE WAS
TAKEN FOR TEMPERATURES TODAY. WITH THE CLOUDS AND FOG THIS
MORNING, IT MAY TAKE A WHILE FOR TEMPERATURES TO START RISING.
HOWEVER, ONCE THE SUN BREAKS OUT, TEMPERATURES SHOULD INCREASE
FAIRLY STEADILY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
ANY SHOWERS/THUNDERSTORMS THAT DEVELOP DURING THE AFTERNOON
SHOULD DISSIPATE AFTER SUNSET AS DAYTIME HEATING IS LOST AND THE
WEAK DISTURBANCE ALOFT PASSES TO OUR EAST. AFTER THE SHOWERS
DISSIPATE, THERE IS A CHANCE FOR FOG TO DEVELOP ONCE AGAIN ACROSS
THE AREA AS THERE WILL STILL BE PLENTY OF LOW-LEVEL MOISTURE.
HOWEVER, SINCE WE WILL NOT BE ON THE NORTHERN SIDE OF ANY
BOUNDARY, AND WE EXPECT WINDS TO BE MORE FROM THE SOUTH-SOUTHWEST,
THE FOG SHOULD NOT BE AS WIDESPREAD OR AS DENSE AS THIS MORNING. A
BLEND OF THE MAV/MET MOS GUIDANCE WAS TAKEN FOR OVERNIGHT
TEMPERATURES AS THEY WERE ONCE AGAIN VERY SIMILAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
IT REMAINS A HIGH CONFIDENCE FORECAST THAT THE PERIOD FROM
TUESDAY THROUGH FRIDAY WITH BE RATHER UNSETTLED WITH THE POTENTIAL
FOR PRECIPITATION EACH DAY. HOWEVER, IT IS A LOW CONFIDENCE
FORECAST REGARDING THE DETAILS AND TIMING. NEVERTHELESS, THE WEEK
SHOULD NOT BE A TOTAL WASHOUT. MOST OF THE TIME, PRECIPITATION
WILL NOT BE FALLING.
THE MID LEVEL PATTERN IS EXPECTED TO FEATURE THE POLAR VORTEX
WELL TO OUR NORTHEAST WITH A CLOSED LOW OVER THE MIDDLE MISSOURI
RIVER VALLEY ON TUESDAY. THERE SHOULD BE A RIDGE EXTENDING FROM
THE WESTERN NORTH ATLANTIC NORTHWESTWARD TO THE GREAT LAKES. THE
POLAR VORTEX WILL REMAIN THE DOMINANT FEATURE OVER EASTERN CANADA
INTO THE WEEKEND. MEANWHILE, THE CLOSED LOW AND ITS ASSOCIATED
TROUGH WILL PROGRESS EASTWARD AND IT SHOULD START TO INTERACT WITH
THE POLAR VORTEX AROUND TUESDAY NIGHT AS THAT FEATURE`S INFLUENCE
BEGINS TO EXPAND TO THE WEST AND SOUTH. THE MID LEVEL TROUGH WILL
LIKELY MOVE EASTWARD ACROSS THE GREAT LAKES FROM WEDNESDAY NIGHT
INTO THURSDAY NIGHT. THE TROUGH`S AXIS SHOULD PASS OVER OUR REGION
IN THE FRIDAY INTO FRIDAY NIGHT TIME FRAME.
A SHOT OF VERY WARM AIR IS FORECAST TO PASS OVER OUR REGION FROM
TUESDAY INTO WEDNESDAY. TEMPERATURES AT 850 HPA ARE EXPECTED TO
RISE INTO THE +15C TO +17C RANGE. THE SURFACE FRONT FROM THE NORTH
IS NO LONGER FORECAST TO DROP INTO OUR REGION. AS A RESULT, WE
EXPECT AFTERNOON TEMPERATURES ON BOTH DAYS TO RISE WELL INTO THE
80S AT MOST LOCATIONS. THE MAIN EXCEPTION WILL BE AREAS ALONG AND
NEAR THE COAST WHERE A SEA BREEZE SHOULD KEEP READINGS FROM
GETTING OUT OF THE 70S AND 60S.
THE HEAT AND THE LOW LEVEL MOISTURE WILL RESULT IN UNSTABLE
CONDITIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS ON
TUESDAY AND WEDNESDAY. WE WILL CONTINUE TO MENTION A CHANCE OF
THUNDERSTORMS WITH SURFACE BASED CAPE VALUES POSSIBLY RISING INTO
THE 1500 TO 2000 J/KG RANGE ESPECIALLY FROM THE INTERSTATE 95
CORRIDOR NORTHWESTWARD. PRECIPITABLE WATER VALUES ARE ANTICIPATED
TO BE IN THE 1.25 TO 1.5 INCH RANGE ON TUESDAY AND AROUND OR
SLIGHTLY GREATER THAN 1.5 INCHES ON WEDNESDAY. AS A RESULT,
LOCALIZED DOWNPOURS REMAIN POSSIBLE..
THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE FAIRLY SIMILAR WITH
THE TIMING OF THE COLD FRONT APPROACHING FROM THE WEST. IT SHOULD
PASS THROUGH OUR REGION FROM LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. WE WILL CONTINUE TO MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT WITH THE FEATURE.
WE WILL KEEP THE POSSIBILITY OF LINGERING SHOWERS IN THE FORECAST
FOR FRIDAY. DRY AIR SHOULD BEGIN TO BUILD INTO OUR REGION AT THAT
TIME AND FAIR WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES ARE
ANTICIPATED FOR SATURDAY AND SUNDAY.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
IFR CONDITIONS PREVAIL ACROSS ALL TAF SITES EARLY THIS MORNING.
CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE THIS MORNING AS A
FRONTAL BOUNDARY SLOWLY LIFTS ACROSS THE AREA. SITES ARE EXPECTED
TO BECOME MVFR/VFR BY LATE MORNING/EARLY AFTERNOON. SCATTERED
SHOWERS AND A FEW ISOLATED THUNDERSTORMS ARE POSSIBLE TODAY,
ESPECIALLY THIS AFTERNOON. CONFIDENCE IN THUNDERSTORMS OCCURRING
IS LOW, SO THEY WERE NOT INCLUDED IN THE TAFS. WINDS THIS MORNING
WILL VARY FROM MORE OF AN EASTERLY DIRECTION NORTH OF THE FRONTAL
BOUNDARY, TO MORE SOUTHERLY SOUTH OF THE BOUNDARY. WINDS WILL
BECOME MORE SOUTH-SOUTHWESTERLY EVERYWHERE LATER THIS MORNING AND
THIS AFTERNOON.
ANY SHOWERS THAT DEVELOP SHOULD DISSIPATE BY SUNSET. FOG/LOW
CLOUDS ARE ONCE AGAIN EXPECTED TO DEVELOP OVERNIGHT MONDAY INTO
TUESDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED TO DEVELOP, BUT
SHOULD NOT BE AS LOW AS THIS MORNING.
OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR. HOWEVER, MVFR AND IFR
CONDITIONS ARE POSSIBLE ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS EACH DAY. ALSO, THERE WILL BE A CHANCE OF SHOWERS
AND AFTERNOON AND EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS
AND REDUCE THE VISIBILITY AT TIMES.
THURSDAY NIGHT...MAINLY VFR. THERE IS A CHANCE OF SHOWERS AND
EVENING THUNDERSTORMS WHICH COULD LOWER CEILINGS AND REDUCE THE
VISIBILITY AT TIMES.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
A SMALL CRAFT ADVISORY REMAINS ACROSS THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON AS SEAS ARE EXPECTED TO REMAIN NEAR 5
FEET ACROSS THE WATERS. EVEN THOUGH WINDS MAY NOT REACH 25 KNOTS,
THEY COULD PERIODICALLY GUST AROUND 20 KNOTS. WIND DIRECTION
ACROSS THE WATERS WILL VARY THIS MORNING DEPENDING ON WHICH SIDE
OF THE FRONTAL BOUNDARY ONE IS. NORTH OF THE BOUNDARY, WINDS WILL
BE MORE EASTERLY; SOUTH OF THE BOUNDARY WINDS WILL BE MORE SOUTH-
SOUTHWESTERLY. WINDS WILL BECOME SOUTH-SOUTHWESTERLY EVERYWHERE
LATER TODAY AFTER THE BOUNDARY AS LIFTED OR DISSIPATED ACROSS THE
ARE.
WE HAVE DECIDED NOT TO EXTEND THE ADVISORY OVERNIGHT MONDAY AS
CONFIDENCE IS NOT HIGH ENOUGH ON WAVES REMAINING 5 FEET OR
GREATER. WE WILL LET LATER SHIFTS TAKE A LOOK AND SEE IF THEY NEED
TO EXTEND THE ADVISORY.
OUTLOOK...
HIGH PRESSURE TO OUR EAST WILL CONTINUE TO INFLUENCE THE COASTAL
WATERS OF NEW JERSEY AND DELAWARE DURING THE MID WEEK PERIOD. A
COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE EARLY ON FRIDAY.
WIND SPEEDS ARE FORECAST TO REMAIN LESS THAN 25 KNOTS FROM
TUESDAY THROUGH FRIDAY WITH ONE EXCEPTION. WIND GUSTS MAY APPROACH
25 KNOTS ON OUR OCEAN WATERS FROM WEDNESDAY NIGHT INTO THURSDAY IN
THE STRENGTHENING SOUTH TO SOUTHWEST FLOW AHEAD OF THE APPROACHING
COLD FRONT. WAVE HEIGHTS ON OUR OCEAN WATERS MAY ALSO BUILD TO
AROUND 5 FEET AT THAT TIME.
MOIST AIR WILL REMAIN OVER THE COASTAL WATERS FROM TUESDAY
THROUGH THURSDAY NIGHT. DEW POINT TEMPERATURES WILL BE NEAR THE
WATER TEMPERATURES. AS A RESULT, THE POTENTIAL FOR FOG EXISTS AND
IT MAY BECOME DENSE AT TIMES.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR PAZ054-055-
060>062-070-071-101>106.
NJ...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR NJZ001-
007>010-012>020-026-027.
DE...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR DEZ001.
MD...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MDZ008.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ450-451.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...IOVINO
AVIATION...IOVINO/ROBERTSON
MARINE...IOVINO/ROBERTSON
000
FXUS61 KLWX 200731
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
331 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WARM FRONT WILL PASS THROUGH THE AREA TODAY WHILE AN UPPER-LEVEL
DISTURBANCE MOVES THROUGH THE AREA. HIGH PRESSURE OVER THE ATLANTIC
WILL PROVIDE A SOUTHERLY FLOW FOR TUESDAY THROUGH
THURSDAY...BRINGING WARM AND HUMID CONDITIONS. A COLD FRONT WILL
PASS THROUGH THE AREA LATE IN THE WEEK AND COOLER CONDITIONS WILL
RETURN FOR NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT ANALYSIS SHOWS A STATIONARY BOUNDARY OVER THE REGION EARLY
THIS MORNING WHILE UPPER-LEVEL LOW PRESSURE SLOWLY MOVES INTO THE
AREA FROM WEST VIRGINIA.
THE STATIONARY BOUNDARY SEPARATES WARM AND MOIST AIR TO THE SOUTH
AND WEST FROM COOLER MARINE AIR TO THE NORTH AND EAST. WIDESPREAD
LOW CLOUDS ALONG WITH FOG/DRIZZLE ARE EXPECTED TO THE NORTH AND
EAST OF THE BOUNDARY ACROSS NORTHEASTERN MARYLAND. HOWEVER...PLENTY
OF MOISTURE IS TRAPPED UNDERNEATH THE NOCTURNAL INVERSION SO AREAS
OF LOW CLOUDS AND FOG/DRIZZLE ARE ALSO EXPECTED SOUTH AND WEST OF
THE BOUNDARY. A FEW SHOWERS ARE POSSIBLE EARLY THIS
MORNING...ESPECIALLY CLOSER TO THE UPPER-LEVEL LOW ACROSS CENTRAL
VIRGINIA.
THE STATIONARY BOUNDARY WILL MOVE NORTH AS A WARM FRONT LATER THIS
MORNING AND AFTERNOON. SOUTHERLY WINDS BEHIND THE BOUNDARY WILL
USHER IN WARM AND HUMID CONDITIONS. THE UPPER-LEVEL LOW WILL SLOWLY
MOVE INTO THE REGION DURING THIS TIME. THE COMBINATION OF WARM AND
HUMID CONDITIONS ALONG WITH COOLER AIR ALOFT WILL CAUSE AN UNSTABLE
ATMOSPHERE THIS AFTERNOON. SHOWERS AND T-STORMS ARE EXPECTED TO
DEVELOP DURING THIS TIME. A LIGHT WIND FIELD AND INSTABILITY
REMAINING SOMEWHAT LIMITED DUE TO CLOUD COVER SHOULD KEEP THE SEVERE
THREAT LOW. SCATTERED SHOWERS/T-STORMS MAY CONTINUE INTO THIS
EVENING...BUT DRY CONDITIONS ARE EXPECTED OVERNIGHT DUE TO THE LOSS
OF DAYTIME HEATING.
WARM AND HUMID CONDITIONS WILL PERSIST OVERNIGHT WITH MIN TEMPS
HOLDING IN THE 60S FOR MOST AREAS. PLENTY OF MOISTURE UNDERNEATH THE
NOCTURNAL INVERSION WILL RESULT IN AREAS OF LOW CLOUDS/FOG.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
MID-ATLANTIC WILL RESIDE IN A WARM SECTOR DURING THE MID-WEEK. THIS
WILL ALLOW FOR A WARM UP TUESDAY THROUGH WEDNESDAY...WITH MAXIMA IN
THE MID 80S. IF THERE IS MORE SUNSHINE...THEN MAXIMA COULD EVEN
REACH UPPER 80S IN SOME LOCATIONS.
TUESDAY MORNING MAY START OFF WITH SOME FOG/STRATUS...BUT CLOUDS
SHOULD BREAK FOR SOME SUNSHINE DURING THE AFTERNOON. MODELS SHOW
MOISTURE IN PLACE...AND SOME INSTABILITY AS WELL HOWEVER AM HAVING
TROUBLE FINDING ANY GOOD FORCING/FOCUSING MECHANISMS FOR CONVECTION
THEREFORE CONTINUE TO FAVOR A DRY FORECAST FOR TUESDAY WITH ONLY
ISOLATED CONVECTION ACROSS THE NORTHWEST.
AIR MASS REMAINS THE SAME ON WEDNESDAY. MODELS HINT AT A BETTER
CHANCE OF DIURNAL CONVECTION SO HAVE INCLUDED CHANCE POPS IN THE
FORECAST FOR SCATTERED THUNDERSTORMS ACROSS THE CWA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SLIGHT HEIGHT FALLS ARE FORECAST TOWARD THE END OF THE WEEK AS AN
UPPER TROUGH APPROACHES...IN TANDEM WITH A COLD FRONT. THERE IS SOME
QUESTION REGARDING TIMING OF THE FROPA...LATEST GUIDANCE SUGGESTING
LATE THURSDAY INTO EARLY FRIDAY. DUE TO UNCERTAINTY HAVE CHANCE POPS
IN THE THURSDAY THROUGH FRIDAY TIME FRAME...AND WE CAN FINE TUNE THE
TIMING AS WE GET CLOSER.
THERE IS GOOD AGREEMENT THAT THE FRONT WILL HAVE MOVED THROUGH THE
AREA BY THE WEEKEND...FAVORING A COOLER/DRIER AIR MASS. FORECAST
REFLECTS MOSTLY CLEAR SKIES AND TEMPERATURES NEAR CLIMATOLOGY.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
PLENTY OF MOISTURE REMAINS TRAPPED UNDERNEATH THE NOCTURNAL
INVERSION. LOW CLOUDS AND AREAS OF FOG WILL CAUSE IFR/SUB IFR
CIGS/VSBYS EARLY THIS MORNING. A WARM FRONT WILL PASS THROUGH THE
TERMINALS LATER THIS MORNING AND CONDITIONS WILL IMPROVE BY LATE
MORNING/EARLY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED...MAINLY THIS AFTERNOON AND EVENING. AREAS OF LOW
CLOUDS/FOG ARE POSSIBLE AGAIN TONIGHT.
THERE IS THE POTENTIAL FOR SOME FOG/STRATUS EARLY
TUESDAY...PARTICULARLY IF SOME OVERNIGHT CLEARING TAKES PLACE AS
LOW LEVEL MOISTURE REMAINS. BUT CONFIDENCE REMAINS ONLY LOW-MODERATE
ON OCCURRENCE ATTM. VFR EXPECTED TO PREVAIL THE BALANCE OF TUESDAY.
CHANCE OF THUNDERSTORMS RETURNS FOR WEDNESDAY AFTERNOON...AND
SHRA/TSRA REMAIN POSSIBLE UNTIL A COLD FRONT MOVES THROUGH LATE
THURSDAY INTO EARLY FRIDAY.
&&
.MARINE...
A STATIONARY BOUNDARY OVER THE WATERS WILL MOVE TO THE NORTH AS A
WARM FRONT TODAY. SOUTHERLY WINDS ARE EXPECTED TODAY THROUGH TONIGHT
BEHIND THIS BOUNDARY. HOWEVER...WIND SPEEDS WILL REMAIN BELOW SCA
CRITERIA. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED...MAINLY
THIS AFTERNOON AND EVENING.
SOUTHERLY WINDS ARE EXPECTED DURING THE MID WEEK UNTIL A COLD FRONT
MOVES THROUGH TOWARD THE END OF THE WEEK SWITCHING WINDS TO THE
NORTHWEST. SOUTHERLY FLOW CHANNELLING UP THE BAY COULD BRING
MARGINAL SCA CONDITIONS UP THE BAY PARTICULARLY DURING THE LATE
AFTERNOON/EVENINGS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES REMAIN NEAR NORMAL EARLY THIS MORNING. SOUTHERLY
WINDS ARE WILL DEVELOP OVER THE WATERS TODAY AND ANOMALIES ARE
EXPECTED TO INCREASE. HOWEVER...THE HIGH TIDE THIS AFTERNOON WILL BE
THE LOWER OF THE TWO. WILL HAVE TO WATCH SOUTHERLY FLOW DURING THE
MID-WEEK AS IT MAY SUPPORT AN INCREASE IN DEPARTURES AGAIN. BUT
CBOFS KEEPS WATER LEVELS BELOW MINOR THRESHOLDS THROUGH HIGH TIDES
TUESDAY AFTERNOON.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BJL/BPP
NEAR TERM...BJL
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BJL/BPP
MARINE...BJL/BPP
TIDES/COASTAL FLOODING...BJL/BPP
000
FXUS61 KPHI 200625
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
225 AM EDT MON MAY 20 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A QUICK UPDATE TO ISSUE A DENSE FOG ADVISORY FOR A GOOD PORTION OF
THE AREA. THE FRONTAL BOUNDARY IS DRAPED ACROSS THE CENTRAL
DELMARVA AND SOUTHERN NEW JERSEY EARLY THIS MORNING. AREAS NORTH
OF THE BOUNDARY HAVE DEVELOPED DENSE FOG WITH WIDESPREAD 1/4-1/2
MILE VISIBILITIES REPORTED. WE WILL RUN IT THROUGH 8 AM AND SEE
HOW THE VISIBILITIES DO OVER THE NEXT FEW HOURS AS THE FRONT TRIES
TO SLOWLY MOVE NORTHWARD.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH FOG WILL
PRECEDE THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS
OVERALL WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT
CHC/LOW CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS
EVENING AND THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE
TOO LOW TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER
50S ACROSS THE NORTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS TONIGHT INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW WILL
REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE AREA.
ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S THEN
SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN EVENTUAL
SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE SHOWS THE
TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
A QUICK UPDATE TO THE FORECAST TO ISSUE A DENSE FOG ADVISORY.
DENSE FOG IS PRETTY WIDESPREAD ON THE LAND, AND WITH DEWPOINTS
NEAR OR HIGHER THAN THE WATER TEMPERATURES, DENSE FOG IS LIKELY
OCCURRING ACROSS A PORTION OF OUR COASTAL WATERS.
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS
AND OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE
SOUTHERN WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE
ONGOING FLAG WILL CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE
SUGGESTS THAT THE CONDITIONS WILL CONTINUE INTO MONDAY...SO WE
WILL EXTEND THE FLAG FOR NOW...ALTHOUGH IT WILL BE A LOW-END
ADVISORY AT BEST. OCNL SHOWERS AND FOG ON THE WATERS TONIGHT AND
SCAT SHOWERS OR A TSTM MONDAY. WINDS WILL VEER TO SRLY LATE
TONIGHT AND THEN BECOME SWRLY ON MONDAY AS THE WARM FRONT CROSSES
THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.EQUIPMENT...
NWR LEWES DE HAS RETURNED TO SERVICE..
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR PAZ054-055-
060>062-070-071-101>106.
NJ...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR NJZ001-
007>010-012>020-026-027.
DE...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR DEZ001.
MD...DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MDZ008.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ450-451.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/ROBERTSON/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/ROBERTSON/O`HARA
EQUIPMENT...
000
FXUS61 KAKQ 200553
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
152 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT WILL SLOWLY PUSH NORTH OF THE AREA TONIGHT AS HIGH
PRESSURE BECOMES ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS
WILL BECOME MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LATEST WX ANALYSIS DEPICTS A RATHER DIFFUSE UPPER LEVEL LOW
SITUATED FROM EASTERN KY TO SW VA AND NC. AT THE SFC...THE FRONTAL
BOUNDARY IS ALSO FAIRLY WEAK...NOW TO THE N OF THE CWA. SFC WINDS
ARE FAIRLY LIGHT AND GENERALLY FROM THE SOUTH. MADE ONLY MINIMAL
CHANGES TO THE FORECAST OVERNIGHT...WITH CHC POPS FOR MOST OF THE
CWA. IR SATELLITE GENLY SHOWS CLOUD TOPS ARE WARMING...DO NOT
EXPECT ANY THUNDER THROUGH THE MORNING HOURS BUT WITH PWATS ~1.5IN
EXPECT MODERATE RAINFALL TO OCCUR DURING ANY SHOWERS...GREATLY
REDUCING VISIBILITIES.
SOME PATCHY FOG IS EXPECTED TO DEVELOP ONCE AGAIN EARLY MONDAY
MORNING... ESPECIALLY IN AREAS NORTH OF INTERSTATE 64 AND ON THE
MARYLAND EASTERN SHORE. WIDESPREAD DENSE FOG IS NOT ANTICIPATED AS
THE FOG SHOULD MAINLY DEVELOP FROM LOWERING STRATUS.
LOW TEMPERATURES MONDAY MORNING ARE FORECAST TO RANGE THROUGH THE
60S ACROSS THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED MONDAY
UNDER THE INFLUENCE OF THE DISSIPATING UPPER LEVEL TROUGH. A BIT
MORE INSTABILITY IS EXPECTED WHICH WILL RESULT IN MORE WIDESPREAD
THUNDERSTORM ACTIVITY THAN WAS EXPERIENCED SUNDAY. HEAVY RAINFALL
WILL BE THE MAIN THREAT WITH ACTIVITY MOVING RATHER SLOWLY. HAVE
LIKELY POPS ACROSS THE SOUTHERN PIEDMONT AND SOUTH CENTRAL VIRGINIA
AND INTO THE NORTH CAROLINA COUNTIES EAST TO NEAR THE CHOWAN RIVER.
HIGH TEMPERATURES WILL BE SLIGHTLY WARMER THAN SUNDAY WITH READINGS
GENERALLY AROUND 80 INLAND AND THE LOW TO MID 70S AT THE COAST.
CONDITIONS SHOULD BEGIN TO DRY OUT MONDAY NIGHT AND TUESDAY AS THE
HIGH PRESSURE OVER THE SOUTHEASTERN STATES BEGINS TO DOMINATE.
HIGHEST POPS (SHOWERS/THUNDERSTORMS) WILL BE IN SOUTHEAST VIRGINIA
AND NORTHEAST NORTH CAROLINA AT 30 PERCENT. TEMPERATURES ARE
FORECAST TO TOP OUT IN THE MID TO UPR 80S IN MOST AREAS WITH UPR 70S
TO LWR 80S NEAR THE COAST AND OVER THE LOWER EASTERN SHORE.
PRECIPITATION SHOULD END BY LATE TUESDAY EVENING.
FOR WEDNESDAY...MODELS ARE ALL OVER THE PLACE WITH POPS. WITH NO
STRONG TRIGGERS FOR CONVECTION OR INDICATIONS OF WHERE CONVECTION
WILL FOCUS...KEPT POPS AT 30 PERCENT THROUGHOUT THE CWA. HIGH
TEMPERATURES WILL BE SIMILAR TO WHAT IS FORECAST FOR TUESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
CONSIDERABLY LESS STRATUS/FOG ACROSS THE AREA AND TERMINALS
TONIGHT VS. LAST NIGHT. MAIN AREA OF POTENTIAL IFR CONDITIONS
APPEARS TO BE ON THE DELMARVA. HAVE KSBY IN IFR THE NEXT 6
HOURS...BASED UPON OBSERVATION TRENDS AT KOXB/KWAL AND KGED.
ELSEWHERE...EXPECT SOME BR...AND PERHAPS SOME STRATUS
DEVELOPMENT...BUT GENERALLY VFR/MVFR CONDITIONS EXPECTED.
INCREASED LO LVL MIXING VICE LAST NIGHT ALSO EXPECTED TO INHIBIT
FOG DEVELOPMENT BEFORE SUNRISE. COULD BE A FEW SHWRS AS
WELL...BUT HAVE LEFT OUT OF MOST TERMINALS DUE TO LACK OF
DEFINITIVE TIMING.
FOR THE MOST PART...EXPECT TODAY TO BE VFR. HOWEVER...SIGNIFICANT
UNCERTAINTY EXISTS WITH REGARD TO POTENTIAL SHWR/TSTM ACTIVITY.
GIVEN INCREASED AMOUNT OF SUNSHINE EXPECTED TODAY...HAVE OPTED TO
INCLUDE PROB30 FOR TSTMS AT MOST TERMINALS IN THE 19Z TO 23Z TIME
FRAME. HEAVIER SHWRS/TSTMS WILL CAUSE BRIEF IFR CONDITIONS. EXPECT
TONIGHT TO BE SIMILAR TO CURRENT CONDITIONS...WITH MAINLY VFR/MVFR
CONDITIONS PREVAILING.
MAINLY VFR IN THE TUE TO THU TIME FRAME...WITH THE POTENTIAL FOR
ISOLD/SCTD SHWRS AND TSTMS BOTH TUE/WED. MORE WIDESPREAD SHWR/TSTM
ACTIVITY EXPECTED THU ALG/AHD OF NEXT CDFNT...WHICH MOVES ACROSS
THE AREA THU/THU NIGHT.
&&
.MARINE...
SE FLOW PREVAILS TNGT AS A WARM FRNT LIFTS NORTH OF THE AREA. HIRES
MODELS SHOW A QUICK SHOT OF SCA WINDS OVER THE BAY LATER THIS
AFTN/EVENG...BUT NOT CONFIDENT ENUF OR LONG LASTING ENUF TO ISSUE A
SCA HEADLINE FOR THIS ATTM. WINDS STAY GENRLY 10-15 KT OVRNGT AND
SHIFT FROM SE TO S. SEAS WILL APPROACH 4-5 FT OUT 20 NM OVER COASTAL
WATERS...WITH BEST CHC FOR 5+ FT OVER THE NORTHERN TWO ZONES WHERE
SCA HEADLINES CONTINUE THRU THE OVRNGT HRS. 12Z WAVEWATCH SHOWS 5 FT
SEAS THERE LASTING INTO MON AND MON NGT...BUT WITH WAVEWATCH
RUNNING HIGH DURING SOUTHERLY FLOW AS OF LATE...WILL END THE SCA AT
4 AM TNGT WITH THE NEXT SHIFT EITHER EXPIRING THE HAZARD OR
EXTENDING IT OUT IN TIME. OTW...SUB-SCA SOUTHERLY WINDS CONTINUE FOR
THE NEXT FEW DAYS AHEAD OF AN APPROACHING COLD FRNT WHICH CROSSES
THE AREA LATE THU/THU NGT.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
ANZ650-652.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/DAP
SHORT TERM...LSA
LONG TERM...JEF
AVIATION...WRS
MARINE...MAS
HYDROLOGY...
000
FXUS61 KPBZ 200541
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
141 AM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR ACTIVITY ON
WEDNESDAY...AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH.
&&
.NEAR TERM /THROUGH TODAY/...
LINGERING SPOTTY SHOWERS OVER THE SOUTHEAST CONTINUE TO DISSIPATE
AS THE ATMOSPHERE STABILIZES. FOR THE REMAINDER OF THE
NIGHT...HAVE REMOVED POPS AND LOWERED CLOUD COVER OVER THE WESTERN
HALF.
REALLY VERY LITTLE CHANGE IN THE WEATHER TODAY...TO THAT WHICH WE
EXPERIENCED OVER THE WEEKEND. EASTERN RIDGE REMAINS IN PLACE WITH
WAVES OF ENERGY MOVING THROUGH THE MID-ATLANTIC REGION. MODELS ARE
HINTING THAT A PIECE OF ENERGY MAY BREAK FROM THE MAIN WAVE AND
MOVE TOWARD MY SOUTHERN ZONES THIS AFTERNOON. THIS COULD BE ENOUGH
TO SPARK A SHOWER OR STORM ACROSS THE SOUTH.
THE ATMOSPHERE WILL BE PLENTY UNSTABLE TODAY...HOWEVER STRONG WAA
ALOFT WILL PROVIDE A CAP...PREVENTING MORE WIDESPREAD CONVECTION
FROM DEVELOPING. ADDITIONALLY...THE 50H RIDGE WILL STRENGTHEN
THIS AFTERNOON INCREASING THE OVERALL SUBSIDENCE.
OVER THE WEEKEND...THE NAM AND GFS HAD BOTH DONE WELL WITH HIGH
TEMPS...SO WILL LEAN CLOSE ON THESE NUMBERS FOR THE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
ANY CONVECTION THAT DEVELOPS TODAY WILL AGAIN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING.
RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY. MODELS CONTINUE TO
PROMOTE WIDESPREAD ACTIVITY LATE TONIGHT AND AGAIN TUE AFTERNOON.
THIS SEEMS TO BE OVERDONE AS THERE IS NO FORCING COMPONENT OR
UPPER LEVEL WAVE TO GET THINGS ROLLING. THINK THE BEST WAY TO
HANDLE THE SITUATION IS TO CONTINUE WITH CHANCE POPS.
EXPECT A BETTER CHANCE FOR SHOWERS AND STORMS WED AS THE RIDGE
BREAKS DOWN AS A RESULT OF LARGE SHORTWAVE TROUGH DIGGING INTO THE
UPPER MIDWEST. MORE SUBSTANTIAL WAVES WILL ROTATE AROUND THIS
FEATURE AND INTO THE UPPER OHIO VALLEY BY WED AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SPOTTY SHOWERS OVER THE EVENING SEEM TO HAVE DISSIPATED...SO
EXPECT THAT THE REST OF THE NIGHT WILL REMAIN DRY. IFR STRATUS IS
EXPECTED TO CONTINUE OVERNIGHT AT DUJ...ALTHOUGH THERE IS SOME
UNCERTAINTY AS TO WHETHER THE STRATUS WILL MANAGE TO PUSH ANY
FARTHER TO THE WEST. HAVE CONTINUED SCT IFR CIGS NEAR DAWN TO
ACCOUNT FOR THIS UNCERTAINTY. CONDITIONS SHOULD RETURN TO VFR AT
ALL LOCATIONS ACROSS THE REGION BY LATE MORNING. AN EXITING UPR
LVL WAVE MAY BRING A SHWR/TSTM E OF PIT BUT CONFIDENCE TOO LOW FOR
MENTION IN TAFS ATTM. ANOTHER ROUND OF MVFR FOG IS POSSIBLE LATE
MONDAY NIGHT INTO TUESDAY MORNING...AND HAVE ADDED THIS IN THE 30
HOUR TAF FOR PIT.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KPBZ 200510
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
110 AM EDT MON MAY 20 2013
.SYNOPSIS...
THE RISK FOR MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS WILL
CONTINUE THROUGH TUESDAY. A BETTER CHANCE FOR ACTIVITY ON
WEDNESDAY...AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH.
&&
.NEAR TERM /THROUGH TODAY/...
LINGERING SPOTTY SHOWERS OVER THE SOUTHEAST CONTINUE TO DISSIPATE
AS THE ATMOSPHERE STABILIZES. FOR THE REMAINDER OF THE
NIGHT...HAVE REMOVED POPS AND LOWERED CLOUD COVER OVER THE WESTERN
HALF.
REALLY VERY LITTLE CHANGE IN THE WEATHER TODAY...TO THAT WHICH WE
EXPERIENCED OVER THE WEEKEND. EASTERN RIDGE REMAINS IN PLACE WITH
WAVES OF ENERGY MOVING THROUGH THE MID-ATLANTIC REGION. MODELS ARE
HINTING THAT A PIECE OF ENERGY MAY BREAK FROM THE MAIN WAVE AND
MOVE TOWARD MY SOUTHERN ZONES THIS AFTERNOON. THIS COULD BE ENOUGH
TO SPARK A SHOWER OR STORM ACROSS THE SOUTH.
THE ATMOSPHERE WILL BE PLENTY UNSTABLE TODAY...HOWEVER STRONG WAA
ALOFT WILL PROVIDE A CAP...PREVENTING MORE WIDESPREAD CONVECTION
FROM DEVELOPING. ADDITIONALLY...THE 50H RIDGE WILL STRENGTHEN
THIS AFTERNOON INCREASING THE OVERALL SUBSIDENCE.
OVER THE WEEKEND...THE NAM AND GFS HAD BOTH DONE WELL WITH HIGH
TEMPS...SO WILL LEAN CLOSE ON THESE NUMBERS FOR THE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
ANY CONVECTION THAT DEVELOPS TODAY WILL AGAIN DISSIPATE WITH THE
LOSS OF DAYTIME HEATING.
RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY. MODELS CONTINUE TO
PROMOTE WIDESPREAD ACTIVITY LATE TONIGHT AND AGAIN TUE AFTERNOON.
THIS SEEMS TO BE OVERDONE AS THERE IS NO FORCING COMPONENT OR
UPPER LEVEL WAVE TO GET THINGS ROLLING. THINK THE BEST WAY TO
HANDLE THE SITUATION IS TO CONTINUE WITH CHANCE POPS.
EXPECT A BETTER CHANCE FOR SHOWERS AND STORMS WED AS THE RIDGE
BREAKS DOWN AS A RESULT OF LARGE SHORTWAVE TROUGH DIGGING INTO THE
UPPER MIDWEST. MORE SUBSTANTIAL WAVES WILL ROTATE AROUND THIS
FEATURE AND INTO THE UPPER OHIO VALLEY BY WED AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
VFR CONDS EXPD INTO THE EVE...EXCPT FOR DUJ WHERE IFR CIGS ARE
EXPD TO CONT OVRNGT. ELSW...COULD SEE SOME PTCHY STRATUS/MVFR BR
DVLPG OVRNGT. EXTENT OF THE STRATUS IS UNCERTAIN...WITH THE MOST
LIKELY PLACES TO SEE CIGS S-E OF PIT...AS WELL AS FKL/DUJ. CONDS
SHOULD RETURN TO VFR ACRS THE RGN MON MRNG. AN EXITING UPR LVL
WAVE MAY BRING A SHWR/TSTM E OF PIT BUT CONFIDENCE TOO LOW FOR
MENTION IN TAFS ATTM.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
000
FXUS61 KAKQ 200434
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1234 AM EDT MON MAY 20 2013
.SYNOPSIS...
A WEAK FRONT WILL SLOWLY PUSH NORTH OF THE AREA TONIGHT AS HIGH
PRESSURE BECOMES ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS
WILL BECOME MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LATEST WX ANALYSIS DEPICTS A RATHER DIFFUSE UPPER LEVEL LOW
SITUATED FROM EASTERN KY TO SW VA AND NC. AT THE SFC...THE FRONTAL
BOUNDARY IS ALSO FAIRLY WEAK...NOW TO THE N OF THE CWA. SFC WINDS
ARE FAIRLY LIGHT AND GENERALLY FROM THE SOUTH. MADE ONLY MINIMAL
CHANGES TO THE FORECAST OVERNIGHT...WITH CHC POPS FOR MOST OF THE
CWA. IR SATELLITE GENLY SHOWS CLOUD TOPS ARE WARMING...DO NOT
EXPECT ANY THUNDER THROUGH THE MORNING HOURS BUT WITH PWATS ~1.5IN
EXPECT MODERATE RAINFALL TO OCCUR DURING ANY SHOWERS...GREATLY
REDUCING VISIBILITIES.
SOME PATCHY FOG IS EXPECTED TO DEVELOP ONCE AGAIN EARLY MONDAY
MORNING... ESPECIALLY IN AREAS NORTH OF INTERSTATE 64 AND ON THE
MARYLAND EASTERN SHORE. WIDESPREAD DENSE FOG IS NOT ANTICIPATED AS
THE FOG SHOULD MAINLY DEVELOP FROM LOWERING STRATUS.
LOW TEMPERATURES MONDAY MORNING ARE FORECAST TO RANGE THROUGH THE
60S ACROSS THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED MONDAY
UNDER THE INFLUENCE OF THE DISSIPATING UPPER LEVEL TROUGH. A BIT
MORE INSTABILITY IS EXPECTED WHICH WILL RESULT IN MORE WIDESPREAD
THUNDERSTORM ACTIVITY THAN WAS EXPERIENCED SUNDAY. HEAVY RAINFALL
WILL BE THE MAIN THREAT WITH ACTIVITY MOVING RATHER SLOWLY. HAVE
LIKELY POPS ACROSS THE SOUTHERN PIEDMONT AND SOUTH CENTRAL VIRGINIA
AND INTO THE NORTH CAROLINA COUNTIES EAST TO NEAR THE CHOWAN RIVER.
HIGH TEMPERATURES WILL BE SLIGHTLY WARMER THAN SUNDAY WITH READINGS
GENERALLY AROUND 80 INLAND AND THE LOW TO MID 70S AT THE COAST.
CONDITIONS SHOULD BEGIN TO DRY OUT MONDAY NIGHT AND TUESDAY AS THE
HIGH PRESSURE OVER THE SOUTHEASTERN STATES BEGINS TO DOMINATE.
HIGHEST POPS (SHOWERS/THUNDERSTORMS) WILL BE IN SOUTHEAST VIRGINIA
AND NORTHEAST NORTH CAROLINA AT 30 PERCENT. TEMPERATURES ARE
FORECAST TO TOP OUT IN THE MID TO UPR 80S IN MOST AREAS WITH UPR 70S
TO LWR 80S NEAR THE COAST AND OVER THE LOWER EASTERN SHORE.
PRECIPITATION SHOULD END BY LATE TUESDAY EVENING.
FOR WEDNESDAY...MODELS ARE ALL OVER THE PLACE WITH POPS. WITH NO
STRONG TRIGGERS FOR CONVECTION OR INDICATIONS OF WHERE CONVECTION
WILL FOCUS...KEPT POPS AT 30 PERCENT THROUGHOUT THE CWA. HIGH
TEMPERATURES WILL BE SIMILAR TO WHAT IS FORECAST FOR TUESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
LOTS OF LOW LVL MOISTURE MEANS A CHC FOR MVFR/IFR CIGS AND VSBY
TO DEVELOP DURING THE OVERNIGHT ALONG WITH PERIODS OF LIGHT RAIN.
IFR CIGS LIKELY TO SETTLE INTO RIC AND SBY BEFORE MIDNIGHT AND
MVFR/IFR CIGS FOR THE OTHER TERMINALS AFTER MIDNIGHT. CLOUDS WILL
PERSIST THRU THE MORNING HOURS BEFORE LIFTING TO MVFR/VFR COND BY
LATE MORNING AND AFTN. WINDS WILL BE GENERALLY SE-S TONIGHT 5-10
KT...AND S-SW ON MON 10-15 KT. MORE SCATTERED SHOWERS AND TSTMS
PSBL MON AFTN WITH THE INSTABILITY AND HEATING...THEN HIGH PRES
EXPECTED TO BUILD OVER THE REGION. MON NIGHT MAY BE PRIME FOR
DENSE FOG DEVELOPING BUT ONLY MENTIONING THAT AS POSSIBLITY AT
THIS TIME.
&&
.MARINE...
SE FLOW PREVAILS TNGT AS A WARM FRNT LIFTS NORTH OF THE AREA. HIRES
MODELS SHOW A QUICK SHOT OF SCA WINDS OVER THE BAY LATER THIS
AFTN/EVENG...BUT NOT CONFIDENT ENUF OR LONG LASTING ENUF TO ISSUE A
SCA HEADLINE FOR THIS ATTM. WINDS STAY GENRLY 10-15 KT OVRNGT AND
SHIFT FROM SE TO S. SEAS WILL APPROACH 4-5 FT OUT 20 NM OVER COASTAL
WATERS...WITH BEST CHC FOR 5+ FT OVER THE NORTHERN TWO ZONES WHERE
SCA HEADLINES CONTINUE THRU THE OVRNGT HRS. 12Z WAVEWATCH SHOWS 5 FT
SEAS THERE LASTING INTO MON AND MON NGT...BUT WITH WAVEWATCH
RUNNING HIGH DURING SOUTHERLY FLOW AS OF LATE...WILL END THE SCA AT
4 AM TNGT WITH THE NEXT SHIFT EITHER EXPIRING THE HAZARD OR
EXTENDING IT OUT IN TIME. OTW...SUB-SCA SOUTHERLY WINDS CONTINUE FOR
THE NEXT FEW DAYS AHEAD OF AN APPROACHING COLD FRNT WHICH CROSSES
THE AREA LATE THU/THU NGT.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
ANZ650-652.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/DAP
SHORT TERM...LSA
LONG TERM...JEF
AVIATION...JEF/JAO
MARINE...MAS
HYDROLOGY...
000
FXUS61 KAKQ 200240
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1040 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A WEAK FRONT WILL SLOWLY PUSH NORTH OF THE AREA TONIGHT AS HIGH
PRESSURE BECOMES ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS
WILL BECOME MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST WX ANALYSIS DEPICTS A RATHER DIFFUSE UPPER LEVEL
LOW SITUATED FROM EASTERN KY TO SW VA AND NC. AT THE SFC...THE
FRONTAL BOUNDARY IS ALSO FAIRLY WEAK...NOW GENLY TO THE N OF THE
CWA. SFC WINDS ARE FAIRLY LIGHT AND SOMEWHAT CHAOTIC IN DIRECTION
DUE TO ONGOING SCATTERED SHRA ACTIVITY. MADE ONLY MINIMAL CHANGES
TO THE FORECAST OVERNIGHT...HAVE A FEW AREAS OF LIKELY POPS
THROUGH MIDNIGHT PER LATEST RADAR TRENDS...WITH CHC POPS FOR MOST
OF THE CWA. IR SATELLITE GENLY SHOWS CLOUD TOPS ARE WARMING...BUT
THERE ARE STILL A FEW SPOTS WHERE SHRA/ISOLATED TSTMS ARE POPPING
UP W/ COOLING CLOUD TOPS.
SOME PATCHY FOG IS EXPECTED TO DEVELOP ONCE AGAIN EARLY MONDAY
MORNING... ESPECIALLY IN AREAS NORTH OF INTERSTATE 64 AND ON THE
MARYLAND EASTERN SHORE. WIDESPREAD DENSE FOG IS NOT ANTICIPATED AS
THE FOG SHOULD MAINLY DEVELOP FROM LOWERING STRATUS.
LOW TEMPERATURES MONDAY MORNING ARE FORECAST TO RANGE THROUGH THE
60S ACROSS THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED MONDAY
UNDER THE INFLUENCE OF THE DISSIPATING UPPER LEVEL TROUGH. A BIT
MORE INSTABILITY IS EXPECTED WHICH WILL RESULT IN MORE WIDESPREAD
THUNDERSTORM ACTIVITY THAN WAS EXPERIENCED SUNDAY. HEAVY RAINFALL
WILL BE THE MAIN THREAT WITH ACTIVITY MOVING RATHER SLOWLY. HAVE
LIKELY POPS ACROSS THE SOUTHERN PIEDMONT AND SOUTH CENTRAL VIRGINIA
AND INTO THE NORTH CAROLINA COUNTIES EAST TO NEAR THE CHOWAN RIVER.
HIGH TEMPERATURES WILL BE SLIGHTLY WARMER THAN SUNDAY WITH READINGS
GENERALLY AROUND 80 INLAND AND THE LOW TO MID 70S AT THE COAST.
CONDITIONS SHOULD BEGIN TO DRY OUT MONDAY NIGHT AND TUESDAY AS THE
HIGH PRESSURE OVER THE SOUTHEASTERN STATES BEGINS TO DOMINATE.
HIGHEST POPS (SHOWERS/THUNDERSTORMS) WILL BE IN SOUTHEAST VIRGINIA
AND NORTHEAST NORTH CAROLINA AT 30 PERCENT. TEMPERATURES ARE
FORECAST TO TOP OUT IN THE MID TO UPR 80S IN MOST AREAS WITH UPR 70S
TO LWR 80S NEAR THE COAST AND OVER THE LOWER EASTERN SHORE.
PRECIPITATION SHOULD END BY LATE TUESDAY EVENING.
FOR WEDNESDAY...MODELS ARE ALL OVER THE PLACE WITH POPS. WITH NO
STRONG TRIGGERS FOR CONVECTION OR INDICATIONS OF WHERE CONVECTION
WILL FOCUS...KEPT POPS AT 30 PERCENT THROUGHOUT THE CWA. HIGH
TEMPERATURES WILL BE SIMILAR TO WHAT IS FORECAST FOR TUESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
LOTS OF LOW LVL MOISTURE MEANS A CHC FOR MVFR/IFR CIGS AND VSBY
TO DEVELOP DURING THE OVERNIGHT ALONG WITH PERIODS OF LIGHT RAIN.
IFR CIGS LIKELY TO SETTLE INTO RIC AND SBY BEFORE MIDNIGHT AND
MVFR/IFR CIGS FOR THE OTHER TERMINALS AFTER MIDNIGHT. CLOUDS WILL
PERSIST THRU THE MORNING HOURS BEFORE LIFTING TO MVFR/VFR COND BY
LATE MORNING AND AFTN. WINDS WILL BE GENERALLY SE-S TONIGHT 5-10
KT...AND S-SW ON MON 10-15 KT. MORE SCATTERED SHOWERS AND TSTMS
PSBL MON AFTN WITH THE INSTABILITY AND HEATING...THEN HIGH PRES
EXPECTED TO BUILD OVER THE REGION. MON NIGHT MAY BE PRIME FOR
DENSE FOG DEVELOPING BUT ONLY MENTIONING THAT AS POSSIBLITY AT
THIS TIME.
&&
.MARINE...
SE FLOW PREVAILS TNGT AS A WARM FRNT LIFTS NORTH OF THE AREA. HIRES
MODELS SHOW A QUICK SHOT OF SCA WINDS OVER THE BAY LATER THIS
AFTN/EVENG...BUT NOT CONFIDENT ENUF OR LONG LASTING ENUF TO ISSUE A
SCA HEADLINE FOR THIS ATTM. WINDS STAY GENRLY 10-15 KT OVRNGT AND
SHIFT FROM SE TO S. SEAS WILL APPROACH 4-5 FT OUT 20 NM OVER COASTAL
WATERS...WITH BEST CHC FOR 5+ FT OVER THE NORTHERN TWO ZONES WHERE
SCA HEADLINES CONTINUE THRU THE OVRNGT HRS. 12Z WAVEWATCH SHOWS 5 FT
SEAS THERE LASTING INTO MON AND MON NGT...BUT WITH WAVEWATCH
RUNNING HIGH DURING SOUTHERLY FLOW AS OF LATE...WILL END THE SCA AT
4 AM TNGT WITH THE NEXT SHIFT EITHER EXPIRING THE HAZARD OR
EXTENDING IT OUT IN TIME. OTW...SUB-SCA SOUTHERLY WINDS CONTINUE FOR
THE NEXT FEW DAYS AHEAD OF AN APPROACHING COLD FRNT WHICH CROSSES
THE AREA LATE THU/THU NGT.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/LSA
SHORT TERM...LSA
LONG TERM...JEF
AVIATION...JEF/JAO
MARINE...MAS
HYDROLOGY...AKQ
000
FXUS61 KPHI 200151
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
951 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH IS EXPECTED TO WEAKEN AND DISSIPATE
AS IT REMAINS NEARLY STATIONARY THROUGH MONDAY. HIGH PRESSURE
CENTERED EAST OF NEW JERSEY WILL SINK SOUTH AND EAST SLOWLY THROUGH
MID-WEEK. ANOTHER HIGH WILL BUILD TOWARD US FROM EASTERN CANADA. AN
ASSOCIATED FRONTAL BOUNDARY FROM THE NORTH IS FORECAST TO MOVE INTO
OR NEAR OUR AREA LATE ON TUESDAY AND THEN LIFT BACK TO THE NORTH
ON WEDNESDAY AND THURSDAY. A COLD FRONT FROM THE WEST IS EXPECTED
TO ARRIVE ON THURSDAY NIGHT OR EARLY FRIDAY, FOLLOWED BY HIGH
PRESSURE FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATE THIS EVENING, PATCHY FOG AND DRIZZLE WERE OBSERVED ACROSS
PORTIONS OF THE FORECAST AREA, ESPECIALLY INTO CENTRAL AND
SOUTHERN PARTS OF NJ AND INTO THE HIGHER TERRAIN OF THE POCONOS.
FARTHER SOUTH, ISOLATED SHOWERS WERE ONGOING INTO CENTRAL PORTIONS
OF OUR DELMARVA AREA, JUST NORTH OF A FRONTAL BOUNDARY. WE
ANTICIPATE THESE TRENDS TO CONTINUE THROUGH THE OVERNIGHT WITH THE
OVERALL ONSHORE FLOW CONTINUING, WITH VERY MOIST AIR PRESENT IN
THE LOW LEVELS. TEMPERATURES THROUGH THE OVERNIGHT WILL LIKELY
REMAIN FAIRLY STEADY OR ONLY DROP ANOTHER COUPLE OF DEGREES.
MINIMUM TEMPERATURES LOOK ON TRACK, AND A FEW TWEAKS WERE MADE TO
HOURLY TEMPS AND DEWPOINTS GOING INTO THE OVERNIGHT HOURS.
OTHERWISE, THE ONSHORE FLOW IN FRONT OF THE APPROACHING WARM
FRONT WILL CONTINUE TONIGHT...THE FRONT WILL CROSS THROUGH
OVERNIGHT. LOW CLOUDS AND DRIZZLE ALONG WITH SOME FOG WILL PRECEDE
THE FRONT AND A FEW SHOWERS ARE POSSIBLE BEHIND IT. POPS OVERALL
WILL SLOWLY DECREASE THROUGH THE NIGHT...ARRIVING AT SLGT CHC/LOW
CHC BY MORNING. WINDS WILL MOSTLY BE ERLY/SERLY THIS EVENING AND
THEN VEER TO SWRLY BY MON MORNING. LOWS WILL NOT BE TOO LOW
TONIGHT...WITH LOWER 60S ACROSS THE SRN AREAS AND UPPER 50S ACROSS
THE NORTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
THERE WILL BE SOME IMPROVEMENT IN THE WEATHER MONDAY. UPPER HEIGHTS
BEHIND THE DEPARTING WARM FRONT WILL BE RISING A LITTLE AND WINDS
THROUGH THE LOWEST LAYERS WILL VEER TO A MORE WRLY DIRECTION. THESE
FACTORS SHOULD ALLOW SOME DRIER AIR TO WORK ITS WAY INTO THE AREA.
THERE WILL STILL BE SOME HIGHER DEW POINTS DURING THE MORNING...AND
ANY SUNSHINE WILL PROBABLY CREATE SOME INSTABILITY SHOWERS DURING
THE AFTERNOON. POPS WILL BE SLGT CHC IN THE MORNING...RISING TO CHC
BY AFTERNOON. CAPE VALUES POINT TO THE POSSIBILITY FOR A FEW
TSTMS...SO THEY WERE LEFT IN THERE FROM BEFORE. WINDS WILL BE MOSTLY
SWRLY AT AROUND 10 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THERE IS BETTER MODEL AGREEMENT THROUGH MUCH OF THE LONG TERM.
WHETHER THAT CONTINUES IS A QUESTION, BUT FOR THE TIME BEING THE
MODELS AGREE AT MID LEVELS THAT THE REMNANTS OF A MID LEVEL LOW THAT
HAS BEEN MOVING SLOWLY EAST WILL MOVE TO NEAR THE MID-ATLANTIC COAST
ON TUESDAY AND THEN WEAKEN AS AN EASTERN U.S./WESTERN ATLANTIC RIDGE
BEGINS TO BUILD. WE CARRY CHANCE TO SLIGHT CHANCE POPS WITH THIS.
THE RIDGE THEN BUILDS AND ESTABLISHES A CONFLUENT ZONE OFF NEW
ENGLAND, AND THAT WILL CARRY AN ASSOCIATED BACK DOOR COLD FRONT AS
SURFACE HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA. WHETHER THE
FRONT MAKES IT INTO OUR AREA IS ANOTHER QUESTION. NEITHER THE LATEST
RUN OF THE GFS NOR THE LAST THREE RUNS OF THE ECMWF ARE BRINGING IT
THIS FAR SOUTH, BUT IT MAY GET CLOSE ENOUGH TO TRIGGER SOME ACTIVITY
IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME. WE CARRY CHANCE TO
SLIGHT CHANCE POPS THAT ARE HIGHEST NORTH.
BY WEDNESDAY, THE BUILDING MID LEVEL RIDGE AXIS WILL BE TO OUR EAST,
AND THAT OPENS US UP TO ANY ENERGY THAT MIGHT BE KICKING OUT AN
ADVANCING AND WEAKENING MID LEVEL LOW. THAT LOW WILL BE PART OF A
REX BLOCK OVER THE NORTHERN PLAINS AND CANADA INTO EARLY WEDNESDAY,
BUT THE MODELS AGREE TO OPEN IT AND MOVE IT INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY. HPC IS HITTING WEDNESDAY POPS PRETTY HARD;
WE`RE NOT QUITE SO SURE ABOUT WHEN ENERGY FROM THE OPENING LOW MAKES
IT HERE AND SO WE CARRY MORE CHANCE POPS THAT ARE BETTER NORTHWEST
AND FOCUSED AROUND WEDNESDAY INTO WEDNESDAY NIGHT.
THROUGH THE ABOVE TIME PERIOD, THERE ALWAYS IS A LOT OF MOISTURE
AVAILABLE AND INSTABILITY GENERALLY WAXES DURING THE AFTERNOON
HOURS. THAT INCREASINGLY BECOMES DUE TO A SOUTH TO SOUTHWEST FLOW
AROUND SURFACE HIGH PRESSURE THAT IS ASSOCIATED WITH THE MID LEVEL
RIDGE AND THAT RESEMBLES A BERMUDA HIGH, AND IT MEANS THAT WHAT THE
PREVIOUS FORECASTER NOTED STILL APPLIES: THERE IS THE POTENTIAL FOR
LOCALIZED DOWNPOURS.
THE LOW FROM THE WEST WEAKENS INTO A NEUTRAL TROUGH ROTATING AROUND
AN EASTERN CANADIAN VORTEX AS IT APPROACHES OUR AREA ON THURSDAY. BY
THE END OF THE DAY, THERE IS AN UPPER JET THAT HAS US IN THE RIGHT
EXIT REGION, AND WITHOUT GOING INTO THE SPECIFICS OF THE FORCING AND
THE WIND FIELDS THIS FAR OUT, AT LEAST SOME OF THAT COME TOGETHER
WITH STILL-COPIOUS MOISTURE OVER THE FORECAST AREA IN A TIME PERIOD
CENTERED AROUND THURSDAY EVENING OR THURSDAY NIGHT. OF COURSE, THE
AMOUNT OF INSTABILITY AVAILABLE IS TO SOME DEGREE DEPENDENT ON WHEN
THE FRONT ARRIVES. THIS SYSTEM SEEMS TO BE THE BEST OPPORTUNITY FOR
ORGANIZED CONVECTION WITH HEAVY DOWNPOURS AND STRONG WINDS, BUT WE
HAVE LOTS OF TIME AND LOTS OF MODEL RUNS TO ASSESS THAT.
WE NOTE THAT THE TIMING OF THIS HAS SPED UP FROM PREVIOUS RUNS
DESPITE THERE BEING A REX BLOCK UPSTREAM EARLIER IN THE PERIOD, BUT
THIS FORECASTER BIT THE BAIT THANKS TO MODEL AGREEMENT. WE PRESENTLY
CARRY LINGERING CHANCE POPS FOR THE FIRST PART OF FRIDAY AND THEN GO
DRY FOR THE REST OF THE FORECAST PERIOD. THE LATEST ECMWF PUSHES
ENERGY MOVING AROUND THE EASTERN CANADIAN VORTEX LATE IN THE WEEKEND
FURTHER SOUTH. THE GFS IS SLOWER WITH SAID ENERGY. THE MID LEVEL
FLOW LOOKS FAIRLY MERIDIONAL, SO EITHER SOLUTION IS A PLAUSIBLE
EXCUSE TO GO OPTIMISTIC.
UNTIL THAT LATE WEEK FRONT ARRIVES, NIGHTTIME MINS WILL BE WELL
ABOVE NORMAL. DAYTIME MAXES ALSO WILL BE ABOVE NORMAL, BUT SUBJECT
TO ANY CONVECTION. IT ALSO WILL BE HUMID UNTIL THE FRONT ARRIVES.
TEMPERATURES WILL RETURN TO NORMAL OR A BIT BELOW NORMAL AFTER THE
FRONT.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
A CONTINUATION OF THE MOSTLY IFR CONDITIONS IS EXPECTED AT THE
TERMINALS TONIGHT INTO MONDAY MORNING. THE SFC/LOW-LEVEL FLOW WILL
REMAIN MOSTLY ONSHORE UNTIL THE SFC WARM FRONT CROSSES THE AREA.
ONCE THIS HAPPENS...LOW LEVEL WINDS WILL BEGIN TO VEER TO S THEN
SW MONDAY. THIS SHOULD ALLOW DRIER AIR TO ARRIVE AND AN EVENTUAL
SCOURING OUT OF THE LOWEST CLOUDS. THE MAV/MET GUIDANCE SHOWS THE
TREND TOMORROW, THE EXACT TIMING MAY BE A FEW HOURS OFF.
MON...SW WINDS WILL INCREASE TO AROUND 10 KNOTS BY AFTERNOON AND
CIGS WILL IMPROVE BACK TO VFR AROUND THE NOON HOUR. THE VFR
CONDITIONS SHOULD LAST INTO THE AFTERNOON...BUT THERE MAY BE A FEW
SCT SHOWERS WITH TEMPORARILY LOWER CONDITIONS LATER MON AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...MVFR AND IFR CONDITIONS ARE POSSIBLE
FROM LATE AT NIGHT TO EARLY IN THE MORNING THROUGH THIS PERIOD.
MAINLY VFR CONDITIONS ARE EXPECTED OTHERWISE, ALTHOUGH THEY
WOULD DETERIORATE IN ANY CONVECTION. CONFIDENCE IS MODERATE.
THURSDAY NIGHT...POSSIBLE CONVECTION WITH ASSOCIATED MVFR OR IFR
CONDITIONS. CONFIDENCE IS LOW ESPECIALLY ON THE TIMING.
FRIDAY...VFR IF CONVECTION CLEARS THE AREA BY THEN. WORSE IF NOT.
CONFIDENCE IS LOW.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO SLOWLY BUILD ACROSS THE OCEAN WATERS AND
OVER DEL BAY. THE SCA CONDITIONS THAT HAVE BEEN ON THE SOUTHERN
WATERS ALREADY APPEAR TO BE HEADING NORTH...SO THE ONGOING FLAG WILL
CONTINUE ACROSS THE OCEAN WATERS. GUIDANCE SUGGESTS THAT THE
CONDITIONS WILL CONTINUE INTO MONDAY...SO WE WILL EXTEND THE FLAG
FOR NOW...ALTHOUGH IT WILL BE A LOW-END ADVISORY AT BEST. OCNL
SHOWERS AND SOME FOG ON THE WATERS TONIGHT AND SCAT SHOWERS OR A
TSTM MONDAY. WINDS WILL VEER TO SRLY LATE TONIGHT AND THEN BECOME
SWRLY ON MONDAY AS THE WARM FRONT CROSSES THE REGION.
OUTLOOK...
WIND SPEEDS ARE FORECAST TO REMAIN SUB-ADVISORY INTO WEDNESDAY
NIGHT, THEN BEGIN TO INCREASE SOME IN ADVANCE OF THE LATE WEEK COLD
FRONT. WAVE HEIGHTS ARE FORECAST TO BE SUB-ADVISORY OVER THE BAY
THROUGH FRIDAY, BUT THEY ARE FORECAST TO START AT ADVISORY LEVELS,
SUBSIDE TO SUB-ADVISORY LEVELS ON TUESDAY BUT THEN RISE AGAIN IN
ADVANCE OF THE COLD FRONT.
&&
.EQUIPMENT...
NWR LEWES DE HAS RETURNED TO SERVICE..
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...KLINE/O`HARA
SHORT TERM...O`HARA
LONG TERM...DELISI
AVIATION...DELISI/O`HARA
MARINE...DELISI/O`HARA
EQUIPMENT...822
000
FXUS61 KAKQ 200138
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
938 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A WEAK FRONT WILL SLOWLY PUSH NORTH OF THE AREA TONIGHT AS HIGH
PRESSURE BECOMES ANCHORED WELL OFF THE COAST. SHOWERS AND THUNDERSTORMS
WILL BECOME MORE WIDELY SCATTERED AFTER MONDAY...WITH ABOVE AVERAGE
TEMPERATURES PREVAILING THROUGH MUCH OF THE UPCOMING WEEK. A COLD
FRONT WILL PASS THROUGH THE MID ATLANTIC STATES LATE THURSDAY INTO
EARLY FRIDAY...WITH COOLER TEMPERATURES EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ADDED FOG TO COASTAL WATERS N OF PARRAMORE ISLAND AS WELL AS THE
ADJACENT PORTIONS OF WORCESTER MD AND ACCOMACK VA THROUGH 9PM AS
RELATIVELY LIGHT SE FLOW OFF THE CHILLY WATERS IS LEADING TO LOW
CLOUDS AND VSBYS < 1 SM AT OXB.
A RATHER DIFFUSE UPPER LEVEL LOW CONTINUES FROM KENTUCKY TO THE
CAROLINAS. A DEEP TROUGH WAS OVER THE NORTHERN HIGH PLAINS. A SMALL
RIDGE WAS IN BETWEEN THE TWO FEATURES. AS THE TROUGH OVER THE PLAINS
STATES CONTINUES TO PRESS EAST...THE UPPER LOW JUST TO OUR WEST AND
THE AFOREMENTIONED RIDGE WILL DISSIPATE. A BERMUDA HIGH PRESSURE
RIDGE EXTENDING FROM THE ATLANTIC TO THE SOUTHEASTERN STATES WILL
BEGIN TO DOMINATE THE AREA WEATHER TOWARD MID WEEK.
THE FRONT THAT HAS BEEN OVER OR JUST SOUTH OF OUR AREA FOR THE LAST
COUPLE OF DAYS IS STILL RATHER DIFFUSE. THERE ARE INDICATIONS THAT
IT HAS MOVED INTO NORTHERN PORTIONS OF THE CWA. THE FRONT IS
EXPECTED TO DISSIPATE OVER NORTHERN PORTIONS OF THE MID ATLANTIC
STATES ON MONDAY.
A VORT LOBE AS INDICATED BY WATER VAPOR IMAGERY WAS ASSOCIATED WITH
A BAND OF TSTMS MOVING INTO OUR SOUTHERN PIEDMONT COUNTIES. THIS
AREA IS EXPECTED TO BE THE MAIN FOCUS FOR SHOWERS AND TSTMS INTO THE
EVENING HOURS WITH LIKELY POPS THROUGH 04Z. WIDELY SCATTERED SHOWERS
CAN BE EXPECTED ELSEWHERE AND KEPT CHANCE POPS THROUGHOUT THE
OVERNIGHT.
SOME PATCHY FOG IS EXPECTED TO DEVELOP ONCE AGAIN MONDAY MORNING...
ESPECIALLY IN AREAS NORTH OF INTERSTATE 64 AND ON THE MARYLAND
EASTERN SHORE. WIDESPREAD DENSE FOG IS NOT ANTICIPATED AS THE FOG
SHOULD MAINLY DEVELOP FROM LOWERING STRATUS.
LOW TEMPERATURES MONDAY MORNING ARE FORECAST TO RANGE THROUGH THE
60S ACROSS THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED MONDAY
UNDER THE INFLUENCE OF THE DISSIPATING UPPER LEVEL TROUGH. A BIT
MORE INSTABILITY IS EXPECTED WHICH WILL RESULT IN MORE WIDESPREAD
THUNDERSTORM ACTIVITY THAN WAS EXPERIENCED SUNDAY. HEAVY RAINFALL
WILL BE THE MAIN THREAT WITH ACTIVITY MOVING RATHER SLOWLY. HAVE
LIKELY POPS ACROSS THE SOUTHERN PIEDMONT AND SOUTH CENTRAL VIRGINIA
AND INTO THE NORTH CAROLINA COUNTIES EAST TO NEAR THE CHOWAN RIVER.
HIGH TEMPERATURES WILL BE SLIGHTLY WARMER THAN SUNDAY WITH READINGS
GENERALLY AROUND 80 INLAND AND THE LOW TO MID 70S AT THE COAST.
CONDITIONS SHOULD BEGIN TO DRY OUT MONDAY NIGHT AND TUESDAY AS THE
HIGH PRESSURE OVER THE SOUTHEASTERN STATES BEGINS TO DOMINATE.
HIGHEST POPS (SHOWERS/THUNDERSTORMS) WILL BE IN SOUTHEAST VIRGINIA
AND NORTHEAST NORTH CAROLINA AT 30 PERCENT. TEMPERATURES ARE
FORECAST TO TOP OUT IN THE MID TO UPR 80S IN MOST AREAS WITH UPR 70S
TO LWR 80S NEAR THE COAST AND OVER THE LOWER EASTERN SHORE.
PRECIPITATION SHOULD END BY LATE TUESDAY EVENING.
FOR WEDNESDAY...MODELS ARE ALL OVER THE PLACE WITH POPS. WITH NO
STRONG TRIGGERS FOR CONVECTION OR INDICATIONS OF WHERE CONVECTION
WILL FOCUS...KEPT POPS AT 30 PERCENT THROUGHOUT THE CWA. HIGH
TEMPERATURES WILL BE SIMILAR TO WHAT IS FORECAST FOR TUESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD STARTS OFF WED NGT WITH A CHC FOR RAIN...MAINLY
WEST OF I-95...AHEAD OF AN APPROACHING MID-LVL TROF AND ASSOCIATED
COLD FRNT. S/SW FLOW WILL KEEP TEMPS ABOVE NORMAL...WITH LOWS IN THE
MID TO UPR 60S. THIS PATTERN CONTINUES INTO THU/THU NGT WITH STILL A
30-40% CHC FOR SHWRS/TSTMS. DEEP-LAYER MOISTURE IS ABUNDANT HOWEVER
FORCING IS A LIMITING FACTOR DUE TO A LACK OF WAA AND MOST S/W
ENERGY STAYING OFF TO THE NORTH. MODELS HAVE CONTINUED TO SPEED UP
THE TIMING OF THE FRNT...WITH THE FROPA NOW EXPECTED TO BE SOMETIME
LATE THU/THU NGT. HIGHS THU IN THE LO TO MID 80S. BEHIND THE FRNT FRI
INTO THE WEEKEND...DIMINISHING CHCS FOR RAIN AND SLGTLY LWR TEMPS
(BUT STILL AROUND SEASONAL NORMS) WITH HIGHS IN THE MID 70S TO LWR
80S AND LOWS IN THE 50S.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
SCATTERED SHOWERS CONT ACROSS THE REGION CONCENTRATED ESP FROM SE
VA TO THE NRN NECK. THE RAIN IS MOVG TO THE N AS SOUTHERLY FLOW
IS PREDOMINATE OVER THE REGION. DOPPER RADAR SHOWING MORE RAIN TO
THE SOUTH OVER CENTRL NC IN RESPONSE TO AN UPPER LVL TROUGH AND
LOW LEVEL CONVERGENCE. MODELS SHOW THE TROUGH SLOWLY WEAKENING AND
MOVG NORTH OVER THE NEXT 24-36 HOURS. THIS WILL ALLOW FOR THE CHC
OF MORE SCATTERED SHOWER AND/OR TSTMS OVER THE REGION FOR MON.
FOR TONIGHT...LOTS OF LOW LVL MOISTURE MEANS A CHC FOR MVFR/IFR
CIGS AND VSBY TO DEVELOP DURING THE OVERNIGHT ALONG WITH PERIODS
OF LIGHT RAIN. IFR CIGS LIKELY TO SETTLE INTO RIC AND SBY BEFORE
MIDNIGHT AND MVFR/IFR CIGS FOR THE OTHER TERMINALS AFTER MIDNIGHT.
CLOUDS WILL PERSIST THRU THE MORNING HOURS BEFORE LIFTING TO
MVFR/VFR COND BY LATE MORNING AND AFTN. WINDS WILL BE GENERALLY
SE-S TONIGHT 5-10 KT...AND S-SW ON MON 10-15 KT. MORE SCATTERED
SHOWERS AND TSTMS PSBL MON AFTN WITH THE INSTABILITY AND
HEATING...THEN HIGH PRES EXPECTED TO BUILD OVER THE REGION. MON
NIGHT MAY BE PRIME FOR DENSE FOG DEVELOPING BUT ONLY MENTIONING
THAT AS POSSIBLITY AT THIS TIME.
&&
.MARINE...
SE FLOW PREVAILS TNGT AS A WARM FRNT LIFTS NORTH OF THE AREA. HIRES
MODELS SHOW A QUICK SHOT OF SCA WINDS OVER THE BAY LATER THIS
AFTN/EVENG...BUT NOT CONFIDENT ENUF OR LONG LASTING ENUF TO ISSUE A
SCA HEADLINE FOR THIS ATTM. WINDS STAY GENRLY 10-15 KT OVRNGT AND
SHIFT FROM SE TO S. SEAS WILL APPROACH 4-5 FT OUT 20 NM OVER COASTAL
WATERS...WITH BEST CHC FOR 5+ FT OVER THE NORTHERN TWO ZONES WHERE
SCA HEADLINES CONTINUE THRU THE OVRNGT HRS. 12Z WAVEWATCH SHOWS 5 FT
SEAS THERE LASTING INTO MON AND MON NGT...BUT WITH WAVEWATCH
RUNNING HIGH DURING SOUTHERLY FLOW AS OF LATE...WILL END THE SCA AT
4 AM TNGT WITH THE NEXT SHIFT EITHER EXPIRING THE HAZARD OR
EXTENDING IT OUT IN TIME. OTW...SUB-SCA SOUTHERLY WINDS CONTINUE FOR
THE NEXT FEW DAYS AHEAD OF AN APPROACHING COLD FRNT WHICH CROSSES
THE AREA LATE THU/THU NGT.
&&
.HYDROLOGY...
RIVER LEVEL FORECASTS HAVE BEEN LOWERED SUBSTANTIALLY DUE TO LACK
OF SIGNIFICANT RAINFALL IN THE HEADWATERS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/LSA
SHORT TERM...LSA
LONG TERM...JEF
AVIATION...JAO
MARINE...MAS
HYDROLOGY...
000
FXUS61 KPBZ 200134
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
934 PM EDT SUN MAY 19 2013
.SYNOPSIS...
A SERIES OF WEATHER DISTURBANCES WILL BRING PERIODIC SHOWER AND
THUNDERSTORM CHANCES THROUGH THURSDAY. HIGH PRESSURE WILL BUILD IN
FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
EVE RAOB PLOTS/STLT DATA SHOW AN UPR LVL WAVE OVR WV. THIS WL
CONT TO DRIFT SLOWLY EWD THRU MON. ISOLD SHWRS S OF PIT SHOULD
CONT TO DMNSH AND GRDLY END OVRNGT. REMOVED TSTMS FM THE FCST AS
INSTAB DROPS OFF. NR TERM MDL DATA SHOWS POTENTIAL FOR STRATUS
DVLPG AREAS N-E OF PIT TNGT AS WELL. WL KEEP CHC POPS FOR
SHWRS/TSTMS MAINLY E-SE OF PIT MON AS THE UPR WV BEGINS TO EXIT TO
THE E. MDL PROGS SHOW INSTAB SHOULD BE MINIMAL MON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
ANY CONVECTION SHOULD BE DSPTG MON EVE AS THE UPR WAVE CONTS TO
MOVE OUT. LOW CHC FOR SHWRS/TSTMS RETURNS TUE AFTN...ALTHOUGH
SOME UPR AND MID LVL RIDGING AND LACK OF A GOOD TRIGGER SHOULD
HELP LMT ACTIVITY. TEMPS WL CONT MUCH ABV AVG.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE DISTRICT REMAINS IN THE WARM SECTOR FOR TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN ABOVE NORMAL ALONG WITH
A CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS. A COLD FRONT
MOVING SLOWLY SOUTH FROM THE GREAT LAKES THURSDAY WILL BRING
LIKELY SHOWERS AND THUNDERSTORMS FOR LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. BEHIND THE COLD FRONT FRIDAY THE RISK OF SHOWERS
WILL DIMINISH AND TEMPERATURES WILL DROP BELOW NORMAL. DRY WEATHER
CAN BE EXPECTED FOR FRIDAY NIGHT INTO SUNDAY WITH TEMPERATURES
FALLING INTO THE 40S FOR OVERNIGHT LOWS SATURDAY MORNING.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
VFR CONDS EXPD INTO THE EVE...EXCPT FOR DUJ WHERE IFR CIGS ARE
EXPD TO CONT OVRNGT. ELSW...COULD SEE SOME PTCHY STRATUS/MVFR BR
DVLPG OVRNGT. EXTENT OF THE STRATUS IS UNCERTAIN...WITH THE MOST
LIKELY PLACES TO SEE CIGS S-E OF PIT...AS WELL AS FKL/DUJ. CONDS
SHOULD RETURN TO VFR ACRS THE RGN MON MRNG. AN EXITING UPR LVL
WAVE MAY BRING A SHWR/TSTM E OF PIT BUT CONFIDENCE TOO LOW FOR
MENTION IN TAFS ATTM.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
CHC FOR SHWR/TSTMS WL RETURN TUE AFTN AND INCR THRU THU EVE AS A
CDFNT APRCHS AND MOVES THRU. BLDG HIGH PRES AND VFR CONDS EXPD
FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
07
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