Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 260746
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
346 AM EDT SUN JUL 26 2015

.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND CROSS THE
AREA TONIGHT AND EARLY MONDAY. THE FRONT WILL REMAIN TO THE SOUTH OF
THE AREA THROUGH EARLY TUESDAY BEFORE DISSIPATING. HIGH PRESSURE
WILL MOVE IN TUESDAY AND REMAIN INTO WEDNESDAY. ANOTHER FRONT WILL
AFFECT THE REGION NEXT THURSDAY AND THURSDAY NIGHT. MORE HIGH
PRESSURE WILL MOVE IN FOR FRIDAY AND INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WHILE THE GFS CONTINUES TO INITIALIZE BETTER THAN THE WRF-NMMB
WITH THE BIG PICTURE AT 500MB, THE WRF-NMMB INITIALIZED BETTER
THAN THE GFS AT 850MB AND 925MB AND IT HAD A VERY GOOD VERIFICATION
OF PREDICTED QPF ACROSS THE NERN CONUS THROUGH 06Z, BESTING
BOTH CANADIANS AND THE ECMWF. THE DP/DT CONTINUES TO SHOW A
STRONGER HEAT RIDGE WITH ITS OVERALL NEWD DEFLECTION OF OTHER
FEATURES.

OVERALL NO CHANGE IN OUR ROAD TOWARD MORE HUMID WEATHER TODAY WITH
SIMILAR MAX TEMPS AS WELL AS THE CHANCE FOR AFTN THUNDERSTORMS. ALSO
THE GENERAL IDEA OF A HIGH DCAPE AND LOW SHEAR ENVIRONMENT (WHERE
THE THUNDER OCCURS TODAY) CONTINUES. LOOKING AT THE MESOSCALE MODELS
FOR THIS MORNING, WITH THE STGST MID LEVEL WAA THROUGH, NO UPSTREAM
CONVECTION AND CONVECTIVE TEMPS OUT OF REACH, WE WILL START THE
FORECAST DRY AT SUNRISE (SHOWERS EARLY FAR NORTH) UNTIL THE
CONVECTIVE TEMP IS REALIZED LATE THIS MORNING/EARLY THIS AFTERNOON
NORTH. PVA COMES IN LATER THIS AFTERNOON WITH BEST MIXED LAYER CAPES
NORTH AND WEST OF THE INTERSTATE 95 CORRIDOR. USED NCAR MIXED LATER
CAPES AOA 1000J AS INITIATION FOR THUNDER. AS THE AFTERNOON
PROGRESSES, GIVEN THAT THE BEST CAPE ONLY SLOWLY EASES SOUTH AND
EAST (ALSO HOW THE CONVECTING MODELS BEGRUDGINGLY BRING CONVECTION
SE OF THE POCONOS), WE WERE CONSERVATIVE WITH POPS GETTING TO THE
I95 CORRIDOR. SOME MESOSCALE MODELS DONT BRING CONVECTIVE CHANCES TO
PHL UNTIL AFTER 04Z. AS FAR AS STRONG/SEVERE GOES, BEST CHANCE MAY
BE IN THE POCONOS BECAUSE OF THEIR PROXIMITY TO AN EVER WEAKENING
LLJ AND PRESENCE OF DECENT DCAPE COINCIDING WITH MAX HEATING. BUT
BULK SHEAR VALUES ARE LOWEST NORTH AND THUS ANY STORMS OF
SIGNIFICANT STRENGTH SHOULD BE ISOLATED AND PULSY.

10C PLUS 925 TEMPS CAME CLOSEST TO FITTING YESTERDAY`S MAX TEMPS.
THESE ARE BASICALLY GIVING OUR CWA A STATUS QUO FOR HIGH TEMPS
TODAY. DEW POINTS THOUGH WILL BE 10 TO 15 DEGREES HIGHER, SO IT WILL
NOT FEEL AS GOOD EVEN WITH MORE OF A BREEZE THAN YESTERDAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
WORKED THROUGH A SIMILAR SCENARIO LAST WEEKEND IN WHICH THE MODELS
WERE DEPICTING CONVECTION GOING THROUGH THE NIGHT.
THE COLD POCKET AT 500MB OVER WISCONSIN OFF THE 00Z SOUNDINGS
WILL BE MOVING OVER OUR CWA OVERNIGHT. THIS PARTIALLY COMPENSATES
FOR A SLIGHT DOWNTICK IN 850MB AND 925MB TEMPS. 850MB MOISTURE IS
PREDICTED TO INCREASE AND THIS APPEARS TO BE THE ULTIMATE DRIVER
TO CONVECTIVE SUSTAINABILITY ALONG WITH A DECENT SHORT WAVE
OVERNIGHT. WE START CINING IN THE EVENING, SO ONGOING CONVECTION
OR LIFT ABOVE THE 925MB FRONT WILL BE NEEDED TO KEEP ON GOING. THE
SURFACE COLD FRONT OVER THE EASTERN GREAT LAKES CURRENTLY WILL BE
VERY DIFFICULT TO FIND OR MAYBE EVEN EXIST BY TONIGHT. MODELS ARE
ALSO DISPLACED AS TO WHETHER BEST CHANCES WILL BE NORTH VS SOUTH
AND ADD TO THAT THE SPC WRF HAS A SAGGING DUE SOUTH COMPLEX
DROPPING NEARLY ENTIRELY WEST OF OUR CWA. WE KEPT POPS IN THE
CHANCE CATEGORY.

BECAUSE OF EXPECTED CLOUDINESS AND HIGHER DEW POINTS, WE WENT AT OR
ABOVE STAT GUIDANCE FOR MINS.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
THE FORMER COLD FRONT...NOW A TROUGH...WILL FURTHER WEAKEN AS IT
CROSSES THE AREA MONDAY AND MONDAY NIGHT. THE GATHERING HEAT AND
HUMIDITY WILL HELP BRING CHCS FOR SHOWERS AND TSTMS WITH THE
FRONT. LOCAL DOWNPOURS EXPECTED. THE EXTRA CLOUDINESS ACROSS THE
AREA WILL HOLD TEMPS DOWN A BIT...BUT THEY WILL STILL BE ABOVE
NORMAL WITH MID/UPPER 80S EXPECTED IN MOST AREAS.

WE WILL KEEP A DRY FCST FOR TUE THROUGH WED NIGHT FOR NOW. HIGH
PRESSURE WILL SETTLE ACROSS THE AREA AS AN UPPER HIGH BUILDS TOO.
THIS WILL BRING DRY WEATHER WITH HOT TEMPERATURES AS WELL. HIGHS
BOTH DAYS WILL BE IN THE 90S IN MANY AREAS...WITH THE WARMER DAY
BEING WED WHERE SOME MID 90S MAY OCCUR ACROSS THE URBAN AREAS. DEW
POINTS WILL BE HIGH TOO...SO A COUPLE OF HEAT RELATED HEADLINES ARE
POSSIBLE.

A COLD FRONT WILL BRING AN END TO THE HEAT AND HUMIDITY LATER THU.
THERE WILL STILL BE SOME TEMPS IN THE 90S BEFORE THE FRONT
ARRIVES...SO MANY AREAS WILL QUALIFY FOR A HEAT WAVE BEFORE THE WEEK
IS OUT. SCT TSTMS ARE EXPECTED WITH THE FRONT SO CHC POPS ARE IN THE
GRIDS FOR NOW. THE FRONT WILL MOVE OFFSHORE THU NIGHT.

FRI AND THE EARLY PART OF THE WEEKEND WILL HAVE MOSTLY DRY WEATHER
FOR THE AREA. A COUPLE SCT TSTMS COULD OCCUR ACROSS THE DELMARVA
REGION WHERE THE AFOREMENTIONED FRONT AND A FEW WEAK WAVES WILL
INTERACT. SLGT CHC POPS ARE IN THE THESE AREAS FOR NOW. TEMPS WILL
STILL BE ABOVE NORMAL...BUT MOSTLY SUB-90 DEGREES AND MOSTLY
COMFORTABLE DEW POINTS...EXCEPT ACROSS THE DELMARVA AND SRN NJ.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

06Z TAFS VFR INTO EARLY AFTERNOON, THEN SOME UNCERTAINTY AS
TO EXTENT OF SHOWERS AND THUNDERSTORMS DURING THE LATE
AFTERNOON AND EVENING.

REST OF THE NIGHT...VFR. LIGHT WINDS, SOME CIRRUS CLOUDS
AROUND. NOT EXPECTING FOG AT TERMINALS AS THERE IS
STILL A FAIRLY LARGE TEMPERATURE AND DEW POINT SPREAD. ALTHOUGH
SOME OF THE MORE SMALLER RURAL AIRPORTS MIGHT HAVE PATCHY GROUND
FOG.

THIS MORNING...VFR. LIGHT SOUTH TO SOUTHWEST WINDS DEVELOPING.

THIS AFTERNOON...VFR WITH STRONGER SOUTH TO SOUTHWEST WINDS
AVERAGING CLOSER TO 10 KNOTS. IF THERE IS A SEA BREEZE FRONT,
ITS TOUGH TO DECIPHER IT AS THE GENERAL FLOW WILL BE EITHER
SOUTH OR SOUTHWEST. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD
START FORMING IN THE NORTHWEST PART OF OUR AREA. BECAUSE OF
THUNDERSTORM EXTENT UNCERTAINTY, THE TEMPO GROUP AT KABE AND KRDG
IS CARRYING MVFR CONDITIONS IN SHOWERS, MIGHT UPGRADE TO THUNDER
WITH 12Z TAFS.

THIS EVENING...VFR CIG EXPECTED. SOUTH WINDS WILL BECOME
LIGHTER. SHOWERS AND THUNDERSTORMS SHOULD SPREAD FARTHER TO
THE SOUTHEAST. BECAUSE INSTABILITY WILL BE DECREASING, TERMINALS
EITHER HAVE SHOWERS OR VCSH. WE KEPT KACY AND KMIV PCPN FREE
AS ANY PRECIPITATION THAT WOULD MAKE IT THERE SHOULD BE AFTER
06Z.


OUTLOOK...
MON/MON NIGHT...VFR EXCEPT IN SCT TSTMS WHERE LOWER CIGS/VSBYS
    POSSIBLE.
TUE THRU WED NIGHT...MOSTLY VFR. AREAS OF HAZE POSSIBLE DURING THE
    DAYTIME HOURS AND PATCHY FOG POSSIBLE AT NIGHT.
THURS...SCT TSTMS WITH LOWER CIGS/VSBYS POSSIBLE.

&&

.MARINE...
WE ARE EXPECTING SUB SMALL CRAFT ADVISORY CONDITIONS TODAY AND
TONIGHT. WINDS WILL BE INCREASING IN THE SOUTH TO SOUTHWEST FLOW
PRECEDING THE WEAKENING COLD FRONT TODAY. THE TREND ON THE LLJ,
IF ONE WANTS TO CALL IT THAT, IS WEAKER. REGARDLESS WE SHOULD
HAVE SOME AROUND 20 KNOT GUSTS THIS AFTERNOON, ESPECIALLY
NEAR THE IMMEDIATE COAST AND INLETS AND ALSO DEVELOPING IN
DELAWARE BAY.

GIVEN THAT THE BEST CONVECTION IS NOT EXPECTED TO REACH THE AREA WATERS UNTIL
TONIGHT, DECREASES THE RISK OF STORMS REACHING SPECIAL MARINE WARNING
CRITERIA. WINDS SHOULD ALSO DIMINISH TONIGHT.

OUTLOOK...
SUB-SCA CONDITIONS EXPECTED MUCH OF THE TIME...EXCEPT FOR THU/THU
NIGHT WHEN SOME LOW END SCA GUSTS/SEAS POSSIBLE. SCT TSTMS MON/MON
NIGHT AND THU/THU NIGHT WILL CREATE LOCALLY HIGHER WINDS AND SEAS.

&&

.RIP CURRENTS...
WITH THE LONG PERIOD (11-12 SECOND) 1 TO 2 FOOT EASTERLY SWELL
CONTINUING...EXPECT THE MODERATE RISK OF DANGEROUS RIP CURRENTS TO
ALSO CONTINUE TODAY.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...O`HARA
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...O`HARA
AVIATION...GIGI/O`HARA
MARINE...GIGI/O`HARA
RIP CURRENTS...GIGI



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