619
FXUS61 KPHI 041845
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
245 PM EDT SAT APR 4 2026
WHAT HAS CHANGED
INCREASED CONFIDENCE IN THE TIMING OF THE FRONT AND THE LINE OF
SHOWERS AND THUNDERSTORMS THAT WILL ACCOMPANY IT ON SUNDAY.
LOW TEMPERATURES FOR THE FIRST FEW DAYS OF NEXT WEEK ARE A
LITTLE COOLER. SOME CONCERN FOR EARLY GROWING SEASON ACTIVITIES.
KEY MESSAGES
1. SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE OVERNIGHT,
AND THEN MORE WIDESPREAD SHOWERS AND STORMS ARE EXPECTED ON
SUNDAY AS A COLD FRONT TRACKS THROUGH THE AREA.
2. COLD TEMPERATURES WEDNESDAY MORNING MAY AFFECT THE
BEGINNING OF THE GROWING SEASON.
DISCUSSION
KEY MESSAGE 1...SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE
OVERNIGHT, AND THEN MORE WIDESPREAD SHOWERS AND STORMS ARE
EXPECTED ON SUNDAY AS A COLD FRONT TRACKS THROUGH THE AREA.
AS THE BACKDOOR COLD FRONT TODAY ADVANCES FURTHER SOUTH, A
SHORT WAVE TROUGH WILL RIDE ALONG THAT BOUNDARY AND MAY TRIGGER
MORE LATE DAY SHOWERS AND POSSIBLE THUNDERSTORMS DUE TO
ELEVATED INSTABILITY.
A SEQUENCE OF FRONTS WILL CROSS THROUGH THE AREA ON SUNDAY AS LOW
PRESSURE TRACKS THROUGH EASTERN CANADA. FIRST, THE BACKDOOR COLD
FRONT TODAY WILL LIFT BACK NORTH AS A WARM FRONT DURING THE
EARLY MORNING HOURS ON SUNDAY. A FEW SHOWERS MAY DEVELOP BEHIND
THIS FRONT.
A LULL IN ACTIVITY IS THEN EXPECTED BEFORE THE COLD FRONT
APPROACHES. THE COLD FRONT IS FORECAST TO CROSS FROM WEST TO
EAST BETWEEN ROUGHLY 14Z/10AM EDT AND 20Z/4 PM EDT. SHOWERS ARE
EXPECTED WITH SOME ISOLATED THUNDERSTORMS POSSIBLE AS A NARROW
CORRIDOR OF INSTABILITY MAY CREEP UP INTO THE COASTAL PLAINS.
AT THIS POINT, THE RISK FOR SEVERE STORMS IS VERY LIMITED. ANY
CONVECTION WILL BE ELEVATED, NOT SURFACE BASED. THE ONLY
LOCATIONS THAT BEAR WATCHING ARE SOUTHERN DELAWARE AND CAPE MAY
COUNTY, WHICH WILL BE THE LAST TO SEE THE COLD FRONT, AND THUS
MAY HAVE A VERY NARROW WINDOW THAT ALTHOUGH THE CONVECTION WILL
BE ELEVATED, A FEW STRONGER WIND GUSTS ABOVE THE INVERSION MAY
MIX DOWN. ANY SHOWER AND THUNDERSTORM ACTIVITY WILL END BY MID
AFTERNOON ONCE THE FRONT IS OFF SHORE.
HIGH TEMPERATURES ON SUNDAY WILL PUSH INTO THE MID 60S TO LOW 70S
DURING THE MORNING HOURS (WITH THE EXCEPTION OF THE POCONOS),
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 2...COLD TEMPERATURES WEDNESDAY MORNING MAY AFFECT THE
BEGINNING OF THE GROWING SEASON.
HIGH PRESSURE WILL BUILD ACROSS THE AREA MONDAY THROUGH WEDNESDAY. A
REINFORCING SURGE OF COLDER AIR WILL ARRIVE LATER TUESDAY WITH
TEMPERATURES DROPPING WELL BELOW NORMAL FOR THE MIDWEEK PERIOD. LOW
TEMPERATURES FOR MON/TUE MORNING WILL BE NEAR NORMAL WITH LOW 40S
FOR DELMARVA AND SOUTH NJ WHILE 30S FOR THE NW COUNTIES (30 FOR
MOUNT POCONO). BY WEDNESDAY MORNING, THE LOWS WILL BE AROUND 10
DEGREES BELOW NORMAL, SO LOWS BELOW FREEZING EVERYWHERE (SAVE
THE SHORE) AND CLOSE TO 20 FOR THE FAR N/W. THESE TEMPS WILL
LEAD TO A WIDESPREAD FROST. WHILE THE GROWING SEASON HAS JUST
STARTED ACROSS DELMARVA, ANY EARLY SEASON ACTIVITIES FOR OTHER
AREAS COULD BE AFFECTED. IT WILL REMAIN BELOW NORMAL THURSDAY
MORNING, BUT WEDNESDAY MORNING LOOKS THE COLDEST AT THIS TIME.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH THE REST OF TODAY...VFR FOR MOST OF THE REMAINDER OF THE
DAY. AFTER 21Z, MARINE LAYER LOW STRATUS COULD START TO MOVE
ONSHORE, RESULTING IN LOWERING CEILINGS. LESS CONFIDENCE NOW ON
THE TIMING OF WHEN THAT STRATUS WILL DEVELOP, BUT LATEST
GUIDANCE TRENDED SLIGHTLY LATER. CURRENT THINKING IS THAT WITH
THE EXCEPTION OF KACY, IFR CEILINGS ARE UNLIKELY BEFORE 00Z.
SOME SHOWERS POSSIBLE THROUGH 00Z, BUT COVERAGE IS EXPECTED TO
BE VERY LIMITED, SO CONFIDENCE THAT ANY ONE TAF SITE WILL SEE
DIRECT IMPACTS IS TOO LOW TO INCLUDE IN THE TAFS. E TO SE WINDS
5 TO 15 KT. LOW CONFIDENCE.
TONIGHT...LOW CLOUDS SHOULD CONTINUE TO SPREAD OVER THE REGION.
BY 03Z, WIDESPREAD IFR WITH POSSIBLE LIFR RESTRICTIONS WILL
DEVELOP FROM THE LOW CEILINGS. SOME VISIBILITY RESTRICTIONS IN
BR OR SHOWERS ARE POSSIBLE, BUT CEILINGS ARE LIKELY TO BE THE
CONTROLLING FACTOR. E WINDS AROUND 10 KTS. THERE IS ALSO A
CONCERN FOR NON-CONVECTIVE LOW LEVEL WIND SHEAR, PARTICULARLY
BETWEEN 06 AND 12Z. LOW CONFIDENCE.
SUNDAY...WILL LIKELY START WITH CEILINGS IFR OR MVFR FOR MOST
TAF SITES. A LINE OF SHRA OR TSRA IS EXPECTED TO MOVE THROUGH
THE REGION FROM W TO E, ARRIVING AT KRDG AND KABE BETWEEN 14 AND
18Z, KPHL, KILG, KPNE, KTTN BETWEEN 15 AND 20Z, AND KMIV AND
KACY BETWEEN 17 AND 21Z. ONCE THE LINE OF SHRA AND TSRA MOVES
BY, CONDITIONS SHOULD RETURN TO VFR QUICKLY. WINDS WILL START S
OR SW AROUND 10 TO 15 KT, BUT WITH THE LINE OF SHRA AND TSRA,
EXPECT AN ABRUPT SHIFT TO W OR EVEN NW WINDS AROUND 10G20KT.
MODERATE CONFIDENCE.
OUTLOOK...
SUNDAY NIGHT... EXCEPT FOR ANY LINGERING SHOWERS ACROSS SOUTHERN NJ
OR DELAWARE DURING SUNDAY EVENING, MOSTLY VFR IS EXPECTED. PATCHY
RURAL FOG POSSIBLE MONDAY MORNING.
MONDAY THRU THURSDAY... VFR EXPECTED MUCH OF THE TIME.
MARINE
WINDS WILL INCREASE LATER THIS AFTERNOON AND TONIGHT ABOVE SMALL
CRAFT ADVISORY CONDITIONS. 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.
SCA CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DAY ON
SUNDAY.
OUTLOOK...
GENERALLY A PERIOD OF SUB-SCA CONDITIONS AND FAIR WEATHER FROM
SUNDAY NIGHT THROUGH THE MIDWEEK. THERE IS A SMALL POSSIBILITY
OF LOW-END SCA CONDITIONS ON TUESDAY AS A COLD FRONT PASSES.
CLIMATE
A VERY WARM AIRMASS SATURDAY MAY CHALLENGE RECORD HIGH
TEMPERATURES AS WELL AS RECORD WARMEST LOW TEMPERATURES FOR
APRIL 4TH. AS OF 2 PM, IT APPEARS THAT PRELIMINARILY, PHL AND
ACY HAVE BROKEN THEIR DAILY RECORD HIGHS FOR TODAY.
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 UNTIL 6 PM EDT SUNDAY FOR ANZ450-451.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 PM EDT
SUNDAY FOR ANZ452>455.
DISCUSSION...JOHNSON/OHARA
AVIATION...JOHNSON/OHARA
MARINE...JOHNSON/OHARA
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