562
FXUS61 KPHI 211826
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
226 PM EDT TUE APR 21 2026
WHAT HAS CHANGED
ADJUSTED TIMING OF SMALL CRAFT ADVISORIES ON THE ATLANTIC
COASTAL WATERS. OTHERWISE, NO SIGNIFICANT CHANGES TO THE
FORECAST.
KEY MESSAGES
1. WEAK LOW PRESSURE WILL CROSS THROUGH THE AREA LATE TONIGHT
INTO WEDNESDAY BRINGING THE CHANCE FOR SOME LIGHT SHOWERS.
2. HIGH PRESSURE BUILDS INTO THE REGION FOR THE END OF THE WORK
WEEK WITH ABOVE NORMAL TEMPERATURES.
3. LOW PRESSURE WILL BRING WIDESPREAD RAINFALL TO THE REGION
THIS WEEKEND.
DISCUSSION
KEY MESSAGE 1...WEAK LOW PRESSURE WILL CROSS THROUGH THE AREA
LATE TONIGHT INTO WEDNESDAY BRINGING THE CHANCE FOR SOME LIGHT
SHOWERS.
LOW PRESSURE CURRENTLY OVER THE UPPER MIDWEST WILL DIVE SOUTH
ACROSS THE GREAT LAKES TONIGHT AND ACROSS THE NORTHERN MID-
ATLANTIC ON WEDNESDAY. SOME LIGHT SHOWERS MAY DEVELOP THIS
EVENING AS FORCING FOR ASCENT INCREASES AHEAD OF A WARM FRONT,
MAINLY TO THE NORTH AND WEST OF I-95. SOME LIGHT SHOWERS MAY
CONTINUE OVERNIGHT, BUT THE GREATER CHANCES FOR SHOWERS WILL
OCCUR IN THE MORNING HOURS ON WEDNESDAY AS LOW PRESSURE ITSELF
TRACKS THROUGH THE AREA. ANY RAINFALL WILL BE RATHER LIGHT IN
NATURE HOWEVER, AS TOTAL QPF WILL GENERALLY RANGE FROM A FEW
HUNDREDTHS TO PERHAPS A TENTH OR TWO. SHOWER ACTIVITY WILL WANE
THROUGH WEDNESDAY AFTERNOON WITH SOME BREAKS OF SUN POSSIBLE
LATE. HIGHS WILL MAINLY BE IN THE UPPER 50S TO UPPER 60S ON
WEDNESDAY WITH LOWS IN THE UPPER 30S TO UPPER 40S.
KEY MESSAGE 2...HIGH PRESSURE BUILDS INTO THE REGION FOR THE
END OF THE WORK WEEK WITH ABOVE NORMAL TEMPERATURES.
A WARM FRONT LIFTS NORTH THROUGH THE REGION WEDNESDAY NIGHT,
THEN HIGH PRESSURE BUILDS OVER THE AREA ON THURSDAY. HIGH
PRESSURE SLIDES OFFSHORE ON FRIDAY, AND THEN A BACK DOOR COLD
FRONT SLIDES THROUGH THE REGION FRIDAY AFTERNOON.
CONDITIONS WILL BE DRY WITH TEMPERATURES WARMING TO ABOVE
NORMAL LEVELS. HIGHS ON THURSDAY WILL TOP OFF IN THE LOW TO MID
70S THROUGHOUT, THOUGH ON THE WARMER SIDE ACROSS INTERIOR
PORTIONS OF SOUTHERN NEW JERSEY AND DELMARVA.
HIGH PRESSURE SLIDES OFFSHORE ON FRIDAY AND A BACK DOOR COLD
FRONT WILL SLIDE SOUTH THROUGH THE REGION. A FEW SHOWERS MAY
DEVELOP, BUT CONDITIONS WILL OTHERWISE BE MOSTLY DRY AND COOLER
WITH HIGHS CLOSER TO NORMAL LEVELS. HIGHS WILL TOP OFF IN THE
LOW TO MID 60S.
KEY MESSAGE 3...LOW PRESSURE WILL BRING WIDESPREAD RAINFALL TO
THE REGION THIS WEEKEND.
LOW PRESSURE ORGANIZES AND DEVELOPS OVER THE GREAT LAKES FRIDAY
NIGHT AND DIVES TOWARDS THE NORTHEAST AND MID-ATLANTIC ON
SATURDAY. SHOWERS ARE LIKELY THROUGHOUT THE DAY, PROVIDING WHAT
LOOKS TO BE A BENEFICIAL RAINFALL WITH AROUND 1/2 INCH OR SO OF
RAIN. IT WILL, HOWEVER, BE OUTRIGHT CHILLY WITH HIGHS IN THE 40S
TO AROUND 50. MOST SHOWERS TAPER OFF SATURDAY NIGHT WITH
LINGERING SHOWERS INTO SUNDAY. HIGHS WILL STILL ONLY BE IN THE
50S ON SUNDAY.
DRY AND WARMER ON MONDAY WITH HIGHS IN THE 60S.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY...VFR WITH MOSTLY CLEAR SKIES. SOUTH-SOUTHWEST
AROUND 5-10 KT. HIGH CONFIDENCE.
TONIGHT...PREVAILING VFR. INCREASING CLOUDS IN THE EVENING WILL
GIVE WAY TO BKN/OVC SKIES OVERNIGHT. A SLIGHT CHANCE OF RAIN
SHOWERS EARLY IN THE EVENING (BETWEEN 00-03Z), BEFORE INCREASING
AGAIN AFTER 06-10Z. A SLIGHT CHANCE OF MVFR CEILINGS WITH
SHOWERS, BUT EXPECT VFR CONDITIONS TO REMAIN. SOUTH-SOUTHEAST
WINDS AROUND 10 KT, LOCALLY HIGHER NEAR KMIV/KACY. MODERATE
CONFIDENCE OVERALL.
WEDNESDAY...PREVAILING VFR FOR MOST TERMINALS, WITH MVFR
CEILINGS LIKELY AT KABE AND POSSIBLY KRDG/KTTN. RAIN SHOWERS
CONTINUE THROUGH THE MORNING AND END FROM NORTHWEST TO SOUTHEAST
BETWEEN 15-18Z. SKIES SHOULD BEGIN TO SCATTER OUT AFTER 18Z.
SOUTH-SOUTHEAST WINDS WILL GRADUALLY BECOME NORTH-NORTHWEST IN
THE AFTERNOON AROUND 5-10 KT. LOW-MODERATE CONFIDENCE.
OUTLOOK...
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...VFR.
FRIDAY...VFR. CANNOT RULE OUT A FEW LIGHT SHRA WITH MINIMAL
RESTRICTIONS.
FRIDAY NIGHT THROUGH SUNDAY...SUB-VFR IN SHRA. IMPROVING CONDS
ON SUNDAY.
MARINE
A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE DELAWARE BAY FROM 2
AM TO 8 AM WEDNESDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR
THE ATLANTIC COASTAL WATERS FROM GREAT EGG INLET TO FENWICK
ISLAND FROM 2 AM TO 11 AM WEDNESDAY. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE ATLANTIC COASTAL WATERS FROM SANDY HOOK TO
GREAT EGG INLET FROM 2 AM TO 1 PM WEDNESDAY.
SOUTH-SOUTHEAST WINDS AROUND 10-15 KT WILL INCREASE TONIGHT TO
AROUND 15-20 KT WITH GUSTS UP TO 25-30 KT. WIND WILL GRADUALLY
DIMINISH THROUGH WEDNESDAY MORNING AND BECOME SOUTHWEST AROUND
10-15 KT BY WEDNESDAY AFTERNOON. SEAS AROUND 3-5 FEET. A CHANCE
FOR RAIN SHOWERS LATE TONIGHT THROUGH WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT THROUGH FRIDAY...SUB-SCA CONDITIONS.
FRIDAY NIGHT THROUGH SUNDAY...SCA CONDITIONS DEVELOP ON
SATURDAY AND PERSIST THROUGH THE WEEKEND. VSBY RESTRICTIONS IN
SHOWERS SATURDAY THROUGH EARLY SUNDAY WITH IMPROVING VSBYS ON
SUNDAY.
CLIMATE
RECORD LOW TEMPERATURES ARE POSSIBLE AT SOME CLIMATE SITES FOR
THIS MORNING, APRIL 21ST. BELOW ARE THE DAILY LOW TEMPERATURE
RECORDS FOR 4/21:
DAILY RECORD LOW TEMPERATURES
APRIL 21
SITE RECORD/YEAR
ALLENTOWN (ABE) 28/1925 & 1956 & 2018
AC AIRPORT (ACY) 25/1981
AC MARINA (55N) 26/1875
GEORGETOWN (GED) 27/1961
MOUNT POCONO (MPO) 11/1908
PHILADELPHIA (PHL) 27/1875
READING (RDG) 26/1982
TRENTON (TTN) 30/1907 & 1925
WILMINGTON (ILG) 28/1925
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 8 AM EDT WEDNESDAY FOR
ANZ430-431.
SMALL CRAFT ADVISORY FROM 2 AM TO 1 PM EDT WEDNESDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY FROM 2 AM TO 11 AM EDT WEDNESDAY FOR
ANZ453>455.
DISCUSSION...DESILVA/MPS
AVIATION...DESILVA/MPS
MARINE...DESILVA/MPS
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