466
FXUS61 KPHI 300609
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
209 AM EDT SUN MAR 30 2025
SYNOPSIS
A COLD FRONT SLIDES SOUTHWEST INTO THE REGION TONIGHT AND STALL
ACROSS THE AREA ON SUNDAY. THIS FRONT FINALLY LIFTS BACK TO THE
NORTHEAST ONCE AND FOR ALL SUNDAY NIGHT INTO EARLY MONDAY,
BEFORE A MORE POWERFUL FRONT MOVES INTO THE REGION FROM THE
NORTHWEST MONDAY NIGHT. HIGH PRESSURE RETURNS TUESDAY AND
WEDNESDAY BEFORE A MORE ACTIVE WEATHER PATTERN ARRIVES FOR THE
END OF THE WEEK.
NEAR TERM /THROUGH TODAY/
A RATHER STRONG BACK DOOR COLD FRONT HAS CLEARED NEARLY ALL OF
OUR NJ AND PA ZONES AS OF 2 AM, AND IS STALLING OUT ACROSS
NORTHERN DELAWARE. COVERAGE OF POST-FRONTAL SHOWERS CONTINUES
TO WANE. WILL HAVE TO SEE WINDS DROP CONSIDERABLY BEFORE THERE
IS ANY SIGNIFICANT FOG DEVELOPMENT. LATEST TRENDS ARE FOR LESS
FOG DEVELOPMENT.
THE FRONTAL BOUNDARY DOES LOOK TO MAKE A SLOW PUSH BACK
NORTHWARD DURING THE DAYTIME ON SUNDAY BEFORE STALLING ACROSS
THE AREA ONCE AGAIN, POTENTIALLY FROM BERKS/LEHIGH SOUTHEASTWARD
TO CENTRAL OCEAN COUNTY IN NEW JERSEY. IF THIS WERE TO PAN OUT,
MOST OF PHILLY WOULD BE SOUTH OF THE FRONT WHILE AREAS NEAR AND
NORTH OF TRENTON WOULD REMAIN ON THE NORTHERN SIDE, THOUGH THIS
REMAIN HIGHLY UNCERTAIN. CONFIDENCE IS HIGHER THAT FOR AREAS
SOUTH OF THE FRONT, ANOTHER WARM DAY IS ON TAP WITH TEMPERATURES
IN THE 70S, WHILE NORTH OF FRONT, TEMPERATURES WILL STRUGGLE TO
HIT 60. CONDITIONS WILL BE PARTLY TO MOSTLY CLOUDY BUT DRY FOR
MUCH OF THE DAY. A FEW SHOWERS MAY MOVE INTO AREAS NORTHWEST OF
THE I-95 CORRIDOR LATE IN THE DAY.
SHORT TERM /TONIGHT THROUGH TUESDAY/
THE STATIONARY BOUNDARY BISECTING THE REGION WILL BEGIN TO
SHIFT NORTHWARD AGAIN AS A WARM FRONT SUNDAY NIGHT, GRADUALLY
BRINGING WARM AIR ADVECTION BACK INTO THE REGION OVERNIGHT. SOME
LEADING UPPER LEVEL ENERGY MAY TRIGGER A FEW SHOWERS NEAR AND
ALONG THIS FRONT, BUT ANY WIDESPREAD PRECIPITATION WILL HOLD OFF
UNTIL MONDAY. NIGHTTIME LOWS WILL BE EARLY ON IN THE NIGHT WITH
LOW-60S AROUND THE PA TURNPIKE/I-195 SOUTH AND UPPER 40S TO LOW
50S FOR AREAS NORTH AND DOWN THE SHORE. TEMPERATURES WILL BE
NON-DIURNAL, HOWEVER, AND GRADUALLY WARM OVERNIGHT AND INTO
EARLY MONDAY MORNING, WITH MONDAY MORNING WAKE-UP TEMPERATURES
IN THE UPPER 50S TO LOW 60S.
A STRONG COLD FRONT WILL APPROACH THE AREA MONDAY AFTERNOON AND
PUSH THROUGH MONDAY NIGHT. STILL QUITE A BIT OF DIFFERENCE
BETWEEN GUIDANCE REGARDING TIMING, BUT AREAS NORTH AND WEST OF
THE I-95 CORRIDOR LOOK TO SEE THE HEAVIEST RAIN AND
THUNDERSTORMS NEAR AND ALONG THE FRONTAL BOUNDARY BEGINNING
MID/LATE AFTERNOON INTO THE EVENING WITH AREAS SOUTH AND EAST
EXPECTED TO SEE MOST OF THE IMPACTS SOMETIME AFTER SUNSET, MORE
IN THE NIGHTTIME HOURS. WE COULD ALSO SEE SOME PRE-FRONTAL
SHOWERS AND THUNDERSTORMS AHEAD OF THIS LINE THROUGHOUT THE
AFTERNOON, THOUGH THERE STILL REMAINS SOME UNCERTAINTY WITH THE
COVERAGE. SKIES ARE EXPECTED TO BE MOSTLY CLOUDY IN THE
AFTERNOON, BUT TEMPERATURES ARE STILL FORECASTED TO WARM INTO
THE LOW TO MID 70S. THE CLOUDY SKIES WILL ALSO HELPING LIMIT
DAYTIME HEATING AND OVERALL INSTABILITY WITH MUCAPE VALUES
LARGELY LESS THAN 1000 J/KG. HOWEVER, THERE WILL BE VERY STRONG
DYNAMICS AND SHEAR IN PLACE, SO MUCH OF THE AREA REMAINS IN A
SLIGHT RISK OF SEVERE WEATHER FROM THE STORM PREDICTION CENTER,
MAINLY FOR DAMAGING WIND GUSTS WITHIN SEVERE THUNDERSTORMS. THE
BEST CHANCE FOR SOME SEVERE WEATHER WILL COME DURING THE
AFTERNOON AND EARLY EVENING WHILE THE HEAVY RAIN THREAT WILL
INCREASE THROUGH THE EVENING AND OVERNIGHT HOURS. A
STRENGTHENING LOW-LEVEL JET DURING THE EVENING AND NIGHTTIME
HOURS WILL SUPPORT PWAT VALUES SURGING INTO THE 1.5 INCH RANGE,
NEAR THE CLIMATOLOGICAL MAXIMUM FOR THIS TIME OF YEAR. AS A
RESULT, FORECASTED STORM TOTAL RAINFALL WILL BE AROUND 0.75-
1.25 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE. DESPITE OUR
ONGOING DROUGHT, THERE ARE LOCALIZED FLOODING CONCERNS,
ESPECIALLY DUE TO POTENTIAL RAINFALL RATES CAUSING SOME
LOCALIZED URBAN FLOODING. ONCE THE COLD FRONT PUSHES THROUGH,
OVERNIGHT LOWS WILL COOL DOWN INTO THE 40S WITH EVEN SOME 30S
OVER THE POCONOS AND NW NJ.
THE COLD FRONT WILL PUSH OFFSHORE EARLY TUESDAY MORNING, GIVING
WAY TO BUILDING HIGH PRESSURE FOR TUESDAY. A SURGE OF NW WINDS
BEHIND THE FRONT CAN BE EXPECTED AFTER DAYBREAK TUESDAY WITH
GUSTS 20-30 MPH POSSIBLE, BEFORE BEGINNING TO SUBSIDE DURING THE
AFTERNOON. INCREASINGLY SUNNY SKIES TUESDAY WITH SEASONABLE
TEMPERATURES IN THE UPPER 40S TO UPPER 50S.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
COLD CANADIAN AIR MASS BUILDS OVERHEAD FOR TUESDAY NIGHT WITH
REDUCING WINDS, SO MOST AREAS AWAY FROM THE COAST AND MARINE
WATERS MAY BE NEAR OR BELOW FREEZING TUESDAY NIGHT. DEPENDING ON
HOW IT PLAYS OUT, MIGHT NEED FROST ADVISORIES OR FREEZE
WARNINGS FOR THE DELMARVA SOUTH OF WILMINGTON, WHERE THE GROWING
SEASON IS DEFINED TO BEGIN ON APRIL 1, THOUGH AT THIS MOMENT WE
ARE NOT FORECASTING TEMPS TO DROP QUITE THAT MUCH. WEDNESDAY
STARTS WITH SOME PARTIAL SUN, THEN CLOUDS INCREASE AS THE NEXT
SYSTEM APPROACHES. HIGHS AGAIN IN THE 50S FOR MOST.
A MORE ACTIVE WEATHER PATTERN IS EXPECTED FOR THE LATTER HALF
OF THE WEEK. MULTIPLE WAVES OF LOW PRESSURE LOOK TO MOVE THROUGH
THE AREA LATER NEXT WEEK IN THE THURSDAY THROUGH SATURDAY
TIMEFRAME. WHILE THERE IS UNCERTAINTY REGARDING THE DETAILS, THE
GENERAL TREND WILL BE FOR IT TO BECOME MORE UNSETTLED WITH
PLENTY OF CHANCES FOR CLOUDS AND RAIN DURING THIS TIMEFRAME.
TEMPERATURES, HOWEVER, WILL BE WARMING WITH HIGHS IN THE 60S AND
70S THROUGH THIS PERIOD.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...FOLLOWING THE EVENING COLD FRONT, LOW CLOUDS
RESULTING IN MVFR AND EVEN IFR CEILINGS WILL FILTER IN. IT NOW
LOOKS AS IF THE FRONT WILL MAKE IT AS FAR SOUTH AS KMIV, BUT
EXPECTING THAT SITE TO STAY VFR THROUGH THE TAF PERIOD. HIGH
CONFIDENCE ON THE OVERALL PATTERN, BUT LOWER CONFIDENCE ON
ARRIVAL OF LOW CEILINGS WHERE THEY HAVE NOT ALREADY ARRIVED.
SUNDAY...THE FRONT SHOULD STALL AND THEN LIFT NORTHWARD,
RESULTING IN IMPROVING CONDITIONS TO VFR AFTER 15Z FOR MOST TAF
SITES. THERE ARE SOME EXCEPTIONS. KRDG, KABE, KTTN, AND KPNE MAY
AROUND THE MVFR THRESHOLD FOR MUCH OF THE AFTERNOON. ONCE THE
FRONT LIFTS NORTHWARD, WINDS WILL BE OUT OF THE SOUTHEAST TO
SOUTH AT AROUND 5-10 KNOTS. MODERATE CONFIDENCE.
OUTLOOK...
SUNDAY NIGHT...SUB-VFR CONDITIONS POSSIBLE EARLY FOR
KTTN/KABE/KRDG BEFORE THE WARM FRONT MOVES NORTH OVERNIGHT WITH
MAINLY VFR CONDITIONS ELSEWHERE. ISOLATED TO SCATTERED SHOWERS
POSSIBLE.
MONDAY AND MONDAY NIGHT...SUB-VFR CONDITIONS DEVELOPING IN THE
AFTERNOON THROUGH THE OVERNIGHT WITH A FRONTAL PASSAGE. HEAVY
RAIN AND THUNDERSTORMS LIKELY. GUSTY WINDS 20-25 KTS.
TUESDAY THROUGH WEDNESDAY...VFR. BREEZY EARLY TUESDAY MORNING.
THURSDAY...SUB-VFR CONDITIONS POSSIBLE WITH SHOWERS LATE.
MARINE
THE SMALL CRAFT ADVISORY FROM SANDY HOOK TO THE GREAT EGG INLET
HAS BEEN EXTENDED THROUGH 6 AM. SEAS HAVE INCREASED
CONSIDERABLY AT BUOY 44065. THOUGH WINDS SHOULD DIMINISH AFTER
MIDNIGHT, HAVE LOW CONFIDENCE ON HOW QUICKLY SEAS WILL DIMINISH
IN THESE AREAS. THUS, EXTENDED THE SCA THROUGH THE NIGHT.
THE FRONT, AND ASSOCIATED WIND SHIFT NOW LOOKS AS IF IT WILL BE
AS FAR SOUTH AS THE DELAWARE BAY BEFORE IT STALLS AND MOVES
NORTH. HOWEVER, NOT AS CONFIDENT WE WILL SEE 25 KT GUSTS FURTHER
SOUTH.
WINDS TURN SOUTHERLY, PARTICULARLY SOUTH OF BARNEGAT LIGHT, ON
SUNDAY, AS THE FRONT LIFTS BACK NORTHWARD SLIGHTLY THEN STALLS
AGAIN. SOUTH OF THE FRONT, WIND GUSTS WILL INCREASE ONCE AGAIN
TO AROUND 20 KNOTS, WITH SOME GUSTS UP TO 25 KNOTS POSSIBLE.
WATERS NORTH OF THE FRONT WILL CONTINUE TO SEE EASTERLY WINDS
AROUND 10 KNOTS. SEAS OF MAINLY 3-4 FEET EXPECTED.
OUTLOOK...
SCA CONDITIONS POSSIBLE SUNDAY NIGHT THROUGH TUESDAY MORNING.
SOUTHERLY WINDS RAMP UP TO 25-30 KTS AHEAD OF A COLD FRONT
SUNDAY NIGHT INTO MONDAY WITH SEAS BUILDING FROM 3-5 FEET TO 5-7
FEET. WINDS SHIFT NWRLY BEHIND THE FRONT, WITH GUSTS STILL
AROUND 25KTS AND SEAS 5-7 FEET EARLY TUESDAY. WINDS AND SEAS
DIMINISH LATER TUESDAY, FALLING BELOW SCA CRITERIA TUESDAY NIGHT
INTO WEDNESDAY. SCA CONDITIONS GRADUALLY RETURN WEDNESDAY NIGHT
INTO THURSDAY.
TIDES/COASTAL FLOODING
WIDESPREAD MINOR TIDAL FLOODING IS POSSIBLE ESPECIALLY WITH THE
SUNDAY NIGHT HIGH TIDE FOR PORTIONS OF THE NJ ATLANTIC COAST
AND SOUTHERN SHORES OF THE RARITAN BAY.
ASTRONOMICAL HIGH TIDES ARE VERY CLOSE TO MINOR FLOOD
THRESHOLDS FOR THE NEXT SEVERAL HIGH TIDE CYCLES WITH THE NEW
MOON ON SATURDAY. WITH THE EXCEPTION OF THE CHESAPEAKE BAY,
ASTRONOMICAL TIDE LEVELS FOR ALL OTHER TIDAL SITES IN OUR REGION
ARE WITHIN ONE FOOT OF MINOR FLOOD THRESHOLDS, AND IN MANY
CASES WITHIN ONE HALF FOOT OF MINOR FLOODING.
FOR THE MOST PART, WINDS WON'T HAVE A STRONG ONSHORE FLOW
COMPONENT, WHICH WILL LIMIT THE AMOUNT OF FLOODING FOR MOST
AREAS. HOWEVER, FOR AREAS THAT END UP NORTH OF THE BACKDOOR COLD
FRONT, LIGHT, BUT PERSISTENT EASTERLY FLOW WILL OCCUR STARTING
TONIGHT CONTINUING THROUGH SUNDAY. AT THIS POINT, WE ARE
EXPECTING THE FRONT TO STALL IN THE AREA OF BARNEGAT BAY.
THE BIGGEST CONCERN AT THIS POINT IS FOR TIDAL LOCATIONS IN
MIDDLESEX AND MONMOUTH COUNTIES WITH THE HIGH TIDE SUNDAY NIGHT.
HOWEVER, HAVE HELD OFF ON A TIDAL FLOOD ADVISORY DUE TO
UNCERTAINTY IN EXACTLY WHERE THE FRONT WILL STALL. ELSEWHERE ON
THE ATLANTIC COAST, DELAWARE BAY, AND TIDAL DELAWARE RIVER, TIDE
LEVELS ARE FORECAST TO BE NEAR BUT JUST BELOW ADVISORY
THRESHOLDS.
ON THE NORTHEASTERN CHESAPEAKE BAY, TIDAL FLOODING ISN'T
EXPECTED DUE TO LOWER ASTRONOMICAL TIDES.
CLIMATE
WE DIDN'T REACH ANY RECORD HIGHS TODAY, THOUGH READING CAME
WITHIN ONE DEGREE. AS FOR THE RECORD WARMEST LOWS, GEORGETOWN
MAY TIE THE WARMEST LOW. ACY IS CURRENTLY ABOVE THE RECORD FOR
THE WARMEST LOW, BUT ASSUMING THE COLD FRONT ARRIVES BEFORE
MIDNIGHT STANDARD TIME, THAT LOW IS LIKELY TO FALL BELOW THE
RECORD.
RECORDS FOR OUR CLIMATE SITES ARE LISTED BELOW:
RECORD HIGH TEMPERATURES
MARCH 29
SITE RECORD/YEAR
ALLENTOWN (ABE) 86/1945
AC AIRPORT (ACY) 87/1945
AC MARINA (55N) 82/1998
GEORGETOWN (GED) 87/1945
MOUNT POCONO (MPO) 79/1945
PHILADELPHIA (PHL) 87/1945
READING (RDG) 87/1907
TRENTON (TTN) 86/1945
WILMINGTON (ILG) 85/1945
RECORD WARMEST LOW TEMPERATURES
MARCH 29
SITE RECORD/YEAR
ALLENTOWN (ABE) 57/1985
AC AIRPORT (ACY) 56/1985
AC MARINA (55N) 58/1985
GEORGETOWN (GED) 61/1989 & 1998
MOUNT POCONO (MPO) 60/1998
PHILADELPHIA (PHL) 63/1907
READING (RDG) 62/1989
TRENTON (TTN) 56/1902 & 1907
WILMINGTON (ILG) 61/1989
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
ANZ450>452.
SYNOPSIS...FITZSIMMONS/MJL
NEAR TERM...AKL/JOHNSON/STAARMANN
SHORT TERM...FITZSIMMONS/MJL
LONG TERM...FITZSIMMONS/MJL
AVIATION...GUZZO/JOHNSON/MJL/STAARMANN
MARINE...AKL/JOHNSON/MJL
TIDES/COASTAL FLOODING...JOHNSON
CLIMATE...STAARMANN
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