445
FXUS61 KPHI 041048
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
648 AM EDT SAT APR 4 2026
WHAT HAS CHANGED
SMALL CRAFT ADVISORIES REISSUED BEGINNING SATURDAY EVENING
THROUGH SUNDAY.
KEY MESSAGES
1. A FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION ON SATURDAY
AS A BACK DOOR COLD FRONT.
2. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ON SUNDAY AS A
COLD FRONT TRACKS THROUGH THE AREA.
3. AN EXTENDED PERIOD OF DRY WEATHER IS EXPECTED FOR THE UPCOMING
WEEK WITH THE RETURN OF WARM TEMPERATURES LATER IN THE WEEK.
DISCUSSION
KEY MESSAGE 1...A FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION
ON SATURDAY AS A BACKDOOR COLD FRONT.
A WARM FRONT THAT LIFTED NORTH OF THE REGION FRIDAY EVENING WILL SAG
BACK SOUTH AS A BACKDOOR COLD FRONT SATURDAY. THE TIMING OF WHEN THE
BACKDOOR FRONT WILL MOVE SOUTH AND HOW FAR SOUTH IT WILL GO IS,
ADMITTEDLY, RATHER UNCERTAIN WITH VARIOUS GUIDANCE IN BROAD
DISAGREEMENT, QUITE TYPICAL IN THESE BACKDOOR FRONT SETUPS. AT ANY
RATE, A DIFFICULT TEMPERATURE FORECAST IS IN STORE FOR SATURDAY WITH
A NON-DIURNAL TEMPERATURE CURVE TODAY FOR MANY LOCATIONS. CURRENT
THINKING IS THIS BACKDOOR COLD FRONT WILL BEGIN ADVANCING
SOUTH/SOUTHWEST IN SOME FASHION BY LATE MORNING/EARLY AFTERNOON.
AREAS NORTH OF THE I-195 CORRIDOR IN NJ COULD SEE TEMPERATURES TOUCH
THE MID 60S TO LOW 70S IN THE MORNING BEFORE SEEING TEMPERATURES
FALL IN THE AFTERNOON. FURTHER INLAND ACROSS EASTERN PA AND SOUTH
ACROSS SOUTHERN NJ AND DELMARVA WILL SEE THIS BACKDOOR FRONT ARRIVE
LATER IN THE AFTERNOON, THEREFORE SEEING A BETTER CHANCE FOR WARMER
TEMPERATURES. PARTICULARLY FOR AREAS AROUND THE PHILLY METRO AND
SOUTH/WEST, WE COULD SEE RECORD-CHALLENGING AFTERNOON HIGHS IN THE
UPPER 70S TO LOW 80S BEFORE THE BACKDOOR FRONT ARRIVES WITH COOLER
TEMPERATURES. DEPENDING ON HOW FAR SOUTH THE FRONT MOVES THROUGH THE
AFTERNOON AND INTO THE LATE NIGHT PERIOD, AREAS ACROSS THE DELMARVA
COULD ALSO SEE NIGHTTIME TEMPERATURES CHALLENGE SOME RECORD WARMEST
LOWS. SEE THE CLIMATE SECTION BELOW FOR INFORMATION ON RECORD
TEMPERATURES FOR APRIL 4TH.
AS THE BACKDOOR FRONT ADVANCES SOUTH AND WEST ACROSS THE REGION,
SOME SHORTWAVE ENERGY WILL RIDE ALONG THAT BOUNDARY AND WILL TRIGGER
SOME LATE DAY SHOWERS AND POSSIBLE THUNDERSTORMS DUE TO ELEVATED
INSTABILITY. BUT DEPENDING ON HOW FAR SOUTH THAT BACK DOOR COLD
FRONT GETS, THAT MAY INHIBIT INSTABILITY NEEDED FOR CONVECTION.
BEHIND THE FRONT, ENE FLOW WILL SUPPORT A STRONG LOW-LEVEL
INVERSION, CAUSING THE DEVELOPMENT OF SOME STRATUS AND FOG SATURDAY
NIGHT.
KEY MESSAGE 2...SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ON
SUNDAY AS A COLD FRONT TRACKS THROUGH THE AREA.
A SEQUENCE OF FRONTS WILL CROSS THROUGH THE AREA ON SUNDAY AS LOW
PRESSURE TRACKS THROUGH EASTERN CANADA. FIRST, A WARM FRONT WILL
LIFT BACK NORTH ACROSS THE MID-ATLANTIC DURING THE EARLY MORNING
HOURS ON SUNDAY. A FEW SHOWERS CAN BE ASSOCIATED WITH THIS FRONT. A
LULL IN ACTIVITY IS THEN EXPECTED BEFORE THE COLD FRONT APPROACHES.
THE COLD FRONT IS THEN FORECAST TO ARRIVE AFTER DAYBREAK AND PUSH
OFFSHORE DURING THE AFTERNOON. SHOWERS ARE LIKELY WITH SOME ISOLATED
THUNDERSTORMS POSSIBLE AS A NARROW CORRIDOR OF INSTABILITY MAY CREEP
UP INTO THE DELMARVA AND SOUTHERN NEW JERSEY REGION. AT THIS POINT,
ANY SEVERE POTENTIAL APPEARS TO BE QUITE LIMITED AS MOST OF THE
INSTABILITY LOOKS TO BE ELEVATED IN NATURE. HOWEVER, A FEW RUMBLES
OF THUNDER CANNOT BE RULED OUT. THIS IS IN LINE WITH THE LATEST
OUTLOOK BY SPC, WHICH ONLY CLIPS THE SOUTHEASTERN-MOST PORTIONS OF
SUSSEX COUNTY, DE IN A MARGINAL RISK. ANY SHOWER AND THUNDERSTORM
ACTIVITY WILL END BY MID AFTERNOON.
HIGH TEMPERATURES ON SUNDAY WILL PUSH INTO THE MID 60S TO LOW 70S
DURING THE MORNING HOURS, BEFORE TEMPERATURES TAKE A TUMBLE IN THE
AFTERNOON IN WAKE OF THE COLD FRONT. WINDS WILL ALSO BE QUITE GUSTY,
ESPECIALLY IN THE MORNING, AS SOUTHERLY FLOW WILL BE ENHANCED AHEAD
OF THE APPROACHING COLD FRONT. GUSTS MAY PUSH UPWARDS OF 30-35 MPH
BEFORE DIMINISHING IN THE AFTERNOON.
KEY MESSAGE 3...AN EXTENDED PERIOD OF DRY WEATHER IS EXPECTED FOR
THE UPCOMING WEEK WITH THE RETURN OF WARM TEMPERATURES LATER IN THE
WEEK.
FOR MONDAY INTO TUESDAY, THE MID-ATLANTIC REGION WILL BE SITUATED
WITHIN THE BASE OF AN UPPER LEVEL TROUGH WHICH WILL DEPART THE
REGION TUESDAY NIGHT. BY WEDNESDAY, A STRENGTHENING MID-LEVEL RIDGE
WILL TAKE SHAPE OVER THE CENTRAL AND EASTERN CONUS THROUGH THE END
OF THE WEEK. AT THE SURFACE, HIGH PRESSURE WILL LARGELY BE IN
CONTROL ASIDE FOR A MEAGER COLD FRONT WHICH WILL PASS THROUGH THE
AREA MONDAY NIGHT INTO TUESDAY. SUPPOSE A STRAY RAIN (OR SNOW)
SHOWER IS POSSIBLE ACROSS FAR NORTHWESTERN AREAS DURING THIS
TIMEFRAME, BUT LARGELY NO PRECIPITATION IS EXPECTED FOR THE UPCOMING
WEEK. AS A RESULT, TEMPERATURES WILL BE SEASONABLY COOL THROUGH
WEDNESDAY, BEFORE BEGINNING TO MODERATE AND TREND BACK TOWARD
SEASONABLY WARM LEVELS BY THURSDAY AND FRIDAY. THIS IS SUPPORTED BY
THE CLIMATE PREDICTION CENTER WHICH OUTLOOKS THE ENTIRE FORECAST
AREA IN A 60-70% CHANCE OF ABOVE-NORMAL TEMPERATURES FOR THE LATE
WEEK PERIOD.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
SATURDAY...A FEW SITES LINGER AT MVFR VSBY EARLY THIS MORNING,
BUT WILL QUICKLY IMPROVE TO PREVAILING VFR THROUGH THE REST OF
THE MORNING. CIGS SHOULD TREND LOWER IN THE AFTERNOON AS A
BACKDOOR COLD FRONT PUSHES SOUTH WITH ALL SITES LIKELY MVFR
AGAIN BY LATE DAY. E WINDS 5 TO 10 KT. CANNOT RULE OUT LATE DAY
SHRA AND PERHAPS A TSRA, MAINLY AT KRDG-KABE- KTTN- KPNE- KPHL.
LOW CONFIDENCE.
SATURDAY NIGHT...WIDESPREAD IFR WITH POSSIBLE LIFR RESTRICTIONS WILL
DEVELOP FROM LOW CIGS NORTH OF THE BACKDOOR COLD FRONT. VIS
RESTRICTIONS WILL LIKELY BE MVFR WITH PATCHY FOG AND SHOWERS.
E WINDS AROUND 10 KTS. LOW CONFIDENCE.
OUTLOOK...
SUNDAY...SUB-VFR CONDITIONS PROBABLE WITH RAIN SHOWERS LIKELY AND
POSSIBLY AN ISOLATED THUNDERSTORM. GUSTY SOUTHWEST WINDS UP TO 25-30
KT POSSIBLE FOR ALL TERMINALS EXCEPT KRDG/KABE.
SUNDAY NIGHT WEDNESDAY...VFR. ASIDE FOR A STRAY RAIN SHOWER AT
KRDG OR KABE ON MONDAY NIGHT, NO SIGNIFICANT WEATHER EXPECTED.
MARINE
MARINE CONDITIONS BELOW SCA CRITERIA FOR A SHORT WINDOW
SATURDAY BEFORE REDEVELOPING SATURDAY EVENING INTO THE OVERNIGHT
HOURS. SW WINDS AROUND 10-15 KTS EARLY WILL SHIFT E BEHIND A
BACKDOOR FRONT. SCA WINDS POSSIBLE SATURDAY EVENING ACROSS THE
NORTHERN OCEAN ZONES WITH E WINDS GUSTING TO AROUND 20-25 KTS.
OVERNIGHT, THE FRONTAL BOUNDARY IS EXPECTED TO LIFT NORTHWARD
AGAIN WITH WINDS TURNING SW AND RAMPING UP TO AROUND 20-25 KTS
WITH SEAS BUILDING TO 4-6 FEET.
OUTLOOK...
SUNDAY THROUGH SUNDAY NIGHT...SCA CONDITIONS LIKELY. WIND GUSTS UP
TO 25-28 KT WITH SEAS AROUND 5-8 FEET. RAIN SHOWERS LIKELY WITH A
SLIGHT CHANCE OF A THUNDERSTORM.
MONDAY THROUGH WEDNESDAY...LINGERING SCA CONDITIONS POSSIBLE ON
MONDAY MORNING, OTHERWISE, NO MARINE HEADLINES ARE EXPECTED THROUGH
WEDNESDAY. FAIR WEATHER.
CLIMATE
A VERY WARM AIRMASS SATURDAY MAY CHALLENGE RECORD HIGH
TEMPERATURES AS WELL AS RECORD WARMEST LOW TEMPERATURES FOR
APRIL 4TH.
RECORD HIGH TEMPERATURES FOR APRIL 4TH:
SITE...................RECORD...YEAR(S)
AC AIRPORT (ACY).......78.......2017
PHILADELPHIA (PHL).....80.......1892
WILMINGTON (ILG).......80.......1950
ALLENTOWN (ABE)........79.......1928
TRENTON (TTN)..........82.......1892
READING (RDG)..........81.......1921
GEORGETOWN (GED).......81.......2023/2011/1963
MOUNT POCONO (MPO).....78.......1928
AC MARINA (55N)........77.......1999
RECORD WARMEST LOW TEMPERATURES FOR APRIL 4TH:
SITE...................RECORD...YEAR(S)
AC AIRPORT (ACY).......56.......1974
PHILADELPHIA (PHL).....60.......2025
WILMINGTON (ILG).......60.......2025
ALLENTOWN (ABE)........60.......1974
TRENTON (TTN)..........62.......1981
READING (RDG)..........58.......2025
GEORGETOWN (GED).......60.......2025/1950
MOUNT POCONO (MPO).....58.......1981
AC MARINA (55N)........56.......2025
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 2 PM EDT SUNDAY FOR ANZ430-
431.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EDT SUNDAY
FOR ANZ450-451.
SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT SUNDAY FOR
ANZ452>455.
DISCUSSION...DESILVA/MJL
AVIATION...DESILVA/MJL
MARINE...DESILVA/MJL
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