589
FXUS61 KPHI 210652
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
152 AM EST FRI NOV 21 2025
SYNOPSIS
HIGH PRESSURE WILL SHIFT OFFSHORE THROUGH FRIDAY. DEVELOPING LOW
PRESSURE WILL PASS OFFSHORE LATE FRIDAY NIGHT FOLLOWED BY HIGH
PRESSURE BUILDING INTO THE REGION THROUGH EARLY NEXT WEEK. A STRONG
FRONTAL SYSTEM LOOKS TO IMPACT THE REGION DURING THE MIDDLE TO END
OF NEXT WEEK.
NEAR TERM /THROUGH SATURDAY/
WEAK HIGH PRESSURE CENTERED NEAR THE AREA WILL BE MOVING
OFFSHORE AND CONTINUING TO WEAKEN AS WE GO THROUGH THE REST OF
THE OVERNIGHT INTO THE DAY FRIDAY. THIS WILL OCCUR AS A FRONTAL
SYSTEM APPROACHES FROM THE GREAT LAKES REGION AS WELL AS A
SEPARATE SOUTHERN STREAM WAVE MOVING FROM OKLAHOMA TOWARDS
TENNESSEE BY LATE DAY FRIDAY. IT SHOULD STAY MAINLY DRY THROUGH
THE DAY FRIDAY THOUGH SKIES WILL GENERALLY BE OVERCAST. THERE
ALSO COULD BE SOME PATCHY FOG AROUND OVERNIGHT UNTIL AROUND MID
MORNING. ACROSS MAINLY OUR EASTERN PA ZONES, THERE COULD ALSO BE
A LITTLE PATCHY DRIZZLE AROUND TOO. THE WARM ADVECTION PATTERN
WILL RESULT IN WARMER HIGHS FOR FRIDAY COMPARED TO THURSDAY WITH
WIDESPREAD 50S GENERALLY EXPECTED EXCEPT SOME UPPER 40S OVER
THE POCONOS AND AROUND 60 OVER OUR SOUTHERN DELMARVA ZONES.
FOR FRIDAY NIGHT INTO SATURDAY, THE POLAR AND SUBTROPICAL JET
WILL ATTEMPT TO PHASE ACROSS THE EASTERN US COAST AMID MODEST
ZONAL FLOW AND BROAD TROUGHING ALOFT. SUBSIDENCE WILL THEN BUILD
INTO THE REGION IN THE WAKE OF THE TROUGH AXIS PUSHING
OFFSHORE.
A SHORTWAVE TROUGH WILL PASS FROM THE OHIO VALLEY AND OFFSHORE FROM
FRIDAY NIGHT THROUGH SATURDAY, RESULTING IN WEAK CYCLOGENESIS EAST
OF THE APPALACHIANS. THIS SYSTEM WILL BRING WIDESPREAD LIGHT
RAINFALL TO THE AREA FRIDAY NIGHT THROUGH SATURDAY MORNING, HEAVIEST
ALONG AND SOUTH OF I-78. RAINFALL AMOUNTS WILL BE LESS THAN
IMPRESSIVE, GENERALLY RANGING FROM .25 TO .50 INCHES OR SO EXCEPT
.10 TO .25 INCHES NORTH OF I-78. LOWS FRIDAY NIGHT WILL BE IN THE
UPPER 30S AND 40S. HIGHS SATURDAY RANGING FROM THE UPPER 40S TO MID
50S. SKIES WILL START OUT MOSTLY CLOUDY TO OVERCAST ON SATURDAY,
THOUGH THERE SHOULD BE SOME CLEARING OF SKIES INTO THE AFTERNOON
HOURS. NNW WINDS AROUND 10 MPH OR SO.
SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/
COOLER AND DRY HIGH PRESSURE WILL SETTLE IN SATURDAY NIGHT THROUGH
SUNDAY. LOWS SATURDAY NIGHT IN THE MID 20S TO MID 30S AND HIGHS
SUNDAY MAINLY IN THE UPPER 40S TO LOW 50S UNDER MAINLY CLEAR SKIES.
WSW WINDS 5-10 MPH.
SUNDAY NIGHT WILL BE A BIT WARMER COMPARED TO SATURDAY NIGHT AS A
WAVE PASSES BY TO OUR NORTH RESULTING IN A LITTLE MORE WIND AND
MIXING IN THE BOUNDARY LAYER. GENERALLY EXPECT LOWS IN THE 30S BUT
IT WILL REMAIN DRY.
LONG TERM /MONDAY THROUGH THURSDAY/
OVERALL SEASONABLE CONDITIONS AND BENIGN WEATHER EXPECTED TO BEGIN
NEXT WEEK FOLLOWED BY A WARMING TREND TUESDAY INTO WEDNESDAY AS THE
NEXT FRONTAL SYSTEM AFFECTS THE AREA. A STRONG COLD FRONT THEN LOOKS
TO MOVE THROUGH AROUND THANKSGIVING DAY BUT THERE ARE SOME MODEL
DIFFERENCES IN THE EXACT TIMING SINCE THIS IS ALMOST A WEEK OUT.
IN TERMS OF DETAILS, THE WEEK BEGINS MAINLY CLEAR FOR MONDAY AS HIGH
PRESSURE WILL BE CENTERED OVER THE AREA WITH SEASONABLE TEMPERATURES
(HIGHS MAINLY IN THE 50S). HEADING INTO TUESDAY, WARM ADVECTION
STRENGTHENS AHEAD OF THE NEXT SYSTEM APPROACHING FROM THE GREAT
LAKES. THIS WILL LEAD TO MILDER TEMPERATURES BUT ALSO INCREASING
CHANCES FOR RAIN BY LATER IN THE DAY AND ESPECIALLY AT NIGHT (POPS
GENERALLY AROUND 70 PERCENT).
HEADING INTO THE MIDDLE TO END OF NEXT WEEK, DIFFERENCES IN THE
FORECAST MODELS INCREASE WITH REGARDS TO HOW QUICKLY THE
AFORMENTIONED SYSTEM MOVES THROUGH. THE GFS DEPICTS A SECONDARY
LOW DEVELOPING NEAR THE TRIPLE POINT WEDNESDAY NIGHT INTO
THANKSGIVING DAY WHICH WOULD KEEP PERIODS OF RAIN/SHOWER AROUND
LONGER BUT ALSO DELAY THE EVENTUAL ARRIVAL OF MUCH COLDER AIR.
MEANWHILE THE ECMWF AND GEM FAVOR A FASTER PROGRESSION OF THE
COLD FRONT THROUGH THE AREA ALONG WITH THE ASSOCIATED UPPER
LEVEL TROUGH. THIS WOULD RESULT IN DRIER BUT MUCH COLDER WEATHER
BUILDING IN FOR THANKSGIVING DAY. GIVEN THIS UNCERTAINTY WE
STAYED WITH THE NATIONAL BLEND OF MODELS WHICH KEEPS A 20-30
PERCENT CHANCE OF RAIN GOING INTO THE FIRST PART OF THURSDAY
WITH HIGHS GENERALLY FORECAST TO BE IN THE UPPER 40S TO MID 50S.
IT SHOULD BE NOTED THOUGH THAT IF THE SYSTEM IS SLOWER IT WILL
BE WARMER AND WETTER (HIGHS THANKSGIVING DAY IN THE 50S TO LOW
60S) WHILE IF IT'S FASTER IT WILL BE COLDER BUT DRY (HIGHS IN
THE 30S TO LOW 40S). REGARDLESS OF THESE DIFFERENCES IN FROPA
TIMING AROUND THANKSGIVING DAY, THE TREND WILL BE FOR MUCH
COLDER AIR TO EVENTUALLY ARRIVE BY NEXT FRIDAY AND PERSIST
THROUGH THANKSGIVING WEEKEND.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...MVFR CEILINGS ARE PRESENT AT MOST TERMINALS AND
ARE EXPECTED TO BE THE PREVAILING CONDITIONS THROUGH THE
OVERNIGHT AT ALL TERMINALS. LIGHT AND VARIABLE WIND WITH PERIOD
OF CALM LIKELY. HIGH CONFIDENCE.
TODAY...MVFR CEILINGS THROUGH 14-17Z. IMPROVEMENT TO VFR IS
FORECAST DURING THE AFTERNOON HOURS. IT IS POSSIBLE THAT SOME
MVFR CEILINGS WILL PREVAIL THROUGH THE DAY. THIS WOULD BE MOST
LIKELY AT KRDG AND KABE. LIGHT WIND WILL BECOME SOUTHWESTERLY
AROUND 5 KT. MODERATE CONFIDENCE.
TONIGHT...MVFR CEILINGS IN THE EVENING. LIGHT RAIN WILL MOVE IN
DURING THE OVERNIGHT HOURS. CEILINGS MAY DROP TO IFR,
PARTICULARLY FOR THE I-95 TERMINALS. VISIBILITY RESTRICTIONS ARE
ALSO POSSIBLE WITH THE RAIN. LIGHT AND VARIABLE WIND WITH
PERIODS OF CALM. MODERATE CONFIDENCE.
OUTLOOK...
SATURDAY...SUB-VFR EARLY IN LIGHT RAIN AND LOW CLOUDS.
CONDITIONS ARE EXPECTED TO IMPROVE LATE IN THE DAY.
SATURDAY NIGHT THROUGH MONDAY NIGHT...VFR. NO SIGNIFICANT
WEATHER.
TUESDAY...VFR TO START, WITH SUB-VFR CONDITIONS POSSIBLE LATER
IN THE DAY IN PERIODS OF LIGHT RAIN.
MARINE
THROUGH FRIDAY, CONDITIONS WILL REMAIN BELOW ADVISORY LEVELS,
ALTHOUGH WINDS WILL INCREASE OUT OF THE SOUTHWEST 10-15 KNOTS BY
LATE DAY.
OUTLOOK...
FRIDAY NIGHT THROUGH TUESDAY...NO SIGNIFICANT WEATHER IMPACTS
ANTICIPATED. A PERIOD OF LIGHT RAIN FRIDAY NIGHT THROUGH EARLY
SATURDAY, THEN WIND GUSTS NEAR 20-25 KTS POSSIBLE DURING THE
DAYTIME SATURDAY. SATURDAY'S DAYTIME PERIOD COULD HAVE MARGINAL
ADVISORY CONDITIONS, BUT LOW CONFIDENCE ON THIS IS STILL LOW.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...FITZSIMMONS/STAARMANN
NEAR TERM...FITZSIMMONS/ROBERTSON
SHORT TERM...FITZSIMMONS/STAARMANN
LONG TERM...FITZSIMMONS
AVIATION...COOPER
MARINE...FITZSIMMONS/ROBERTSON/STAARMANN
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