599
FXUS61 KPHI 010558
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
158 AM EDT TUE APR 1 2025
SYNOPSIS
A COLD FRONT WILL CONTINUE TO CROSS THE NORTHERN MIDDLE
ATLANTIC REGION OVERNIGHT. HIGH PRESSURE RETURNS FOR TUESDAY AND
WEDNESDAY. A WARM FRONT WILL LIFT NORTH OF THE AREA ON THURSDAY
BEFORE SINKING BACK TO OUR SOUTH ON FRIDAY. A SEQUENCE OF LOWS
AND DISTURBANCES WILL RIDE ALONG THIS BOUNDARY CAUSING UNSETTLED
CONDITIONS TO OCCUR LATE IN THE WEEK THROUGH THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
155 AM...THE COLD FRONT IS BEGINNING TO WORK ITS WAY ACROSS THE
REGION AND WILL MOVE OFFSHORE BEFORE DAWN. THIS WILL BRING THE
LINGERING RAIN TO AN END FROM WEST TO EAST. BEHIND THE FRONT, NW
WINDS WILL INCREASE TO AROUND 15 GUSTING 20 TO 30 MPH AT TIMES.
BY MORNING, EXPECT LOWS RANGING FROM THE MID TO UPPER 30S NORTH
TO THE MID/UPPER 40S SOUTH.
FOR THE DAY TUESDAY, WE WILL STILL BE IN A POST FRONTAL, COLD
ADVECTION REGIME WITH 850 MB TEMPERATURES DROPPING TO AROUND -4C TO
2C. THIS WILL TRANSLATE TO HIGH TEMPERATURES GENERALLY RANGING FROM
THE MID TO UPPER 50S NEAR AND SOUTH OF THE URBAN CORRIDOR WITH LOW
50S FOR MOST AREAS FARTHER NORTH, EXCEPT 40S IN THE HIGHER
ELEVATIONS. BREEZY NW WINDS AROUND 10 TO 15 WITH GUSTS UP TO 25 MPH
WILL CONTINUE THROUGH THE EARLY AFTERNOON BEFORE SLOWLY STARTING DO
DIMINISH AS SURFACE HIGH PRESSURE BUILDS IN TO OUR NORTH AND THE
GRADIENT WEAKENS.
HIGH PRESSURE TO OUR NORTH WILL BEGIN SHIFTING EAST TUESDAY NIGHT
WHICH WILL LEAD TO SURFACE WINDS BECOMING MORE NORTHEASTERLY. WINDS
SHOULD REMAIN ELEVATED ENOUGH ON THE OUTER PERIPHERY OF THE HIGH
AROUND 5- 10 MPH, BUT THE USUAL SHELTERED SPOTS WILL LIKELY GO CALM
AND RADIATE WELL UNDER MOSTLY CLEAR SKIES. THIS IS NOTEWORTHY
BECAUSE THE FROST/FREEZE PROGRAM BEGINS APRIL 1 FOR OUR DELMARVA
COUNTIES. WITH THE DRY AIRMASS IN PLACE AND A COOL NORTHEAST BREEZE,
THIS SHOULD LIMIT/PREVENT ANY FROST DEVELOPMENT DESPITE THE LOW
TEMPS IN THE MID TO UPPER 30S. FURTHER NORTH, LOWS WILL BE IN THE
UPPER 20S TO MID 30S, BUT THE GROWING SEASON IS NOT ACTIVE YET IN
THESE LOCATIONS TO WARRANT ANY FREEZE HEADLINES.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/
UPPER TROUGHING WILL PUSH OFFSHORE BY TUESDAY NIGHT, FOLLOWED
BY ZONAL FLOW FOR WEDNESDAY AND UPPER RIDGING FOR WEDNESDAY
NIGHT INTO THURSDAY. AT THE SURFACE, COOL AND DRY CANADIAN HIGH
PRESSURE WILL BUILD INTO THE REGION TUESDAY NIGHT INTO
WEDNESDAY. A WARM FRONT WILL THEN LIFT NORTH THROUGH THE AREA
WEDNESDAY NIGHT AS A STRONG LOW PASSES THROUGH THE NORTHERN
GREAT LAKES ON THURSDAY.
HIGH PRESSURE WILL BEGIN SHIFTING EAST ON TUESDAY NIGHT WHICH
WILL LEAD TO SURFACE WINDS BECOMING MORE NORTHEASTERLY. WINDS
SHOULD REMAIN ELEVATED ENOUGH ON THE OUTER PERIPHERY OF THE HIGH
AROUND 5- 10 MPH, BUT THE USUAL SHELTERED SPOTS WILL LIKELY GO
CALM AND RADIATE WELL UNDER MOSTLY CLEAR SKIES. THIS IS
NOTEWORTHY BECAUSE THE FROST/FREEZE PROGRAM BEGINS APRIL 1 FOR
OUR DELMARVA COUNTIES. WITH THE DRY AIRMASS IN PLACE AND A COOL
NORTHEAST BREEZE, THIS SHOULD LIMIT/PREVENT ANY FROST
DEVELOPMENT DESPITE THE LOW TEMPS IN THE MID TO UPPER 30S.
FURTHER NORTH, LOWS WILL BE IN THE UPPER 20S TO MID 30S, BUT THE
GROWING SEASON IS NOT ACTIVE YET IN THESE LOCATIONS TO WARRANT
ANY FREEZE HEADLINES.
FOR WEDNESDAY, THE HIGH WILL CONTINUE TO EXIT AND SHIFT OFF THE
COAST OF NEW ENGLAND. SHOULD SEE MOSTLY CLEAR SKIES EARLY IN
THE DAY, BECOMING MORE CLOUD-FILLED IN THE AFTERNOON. WINDS WILL
BECOME SOUTHEASTERLY DUE TO THE POSITIONING OF THE HIGH,
CAUSING A MORE ONSHORE COMPONENT. IT WILL ALSO BECOME BREEZY ON
WEDNESDAY WITH WINDS INCREASING TO 10-20 MPH WITH GUSTS LOCALLY
UP TO 30 MPH. HIGH TEMPERATURES SHOULD RANGE FROM THE UPPER 40S
TO UPPER 50S FROM NORTH TO SOUTH.
BY WEDNESDAY NIGHT AND THURSDAY, WE WILL BEGIN TO SEE
SIGNIFICANT CHANGES AROUND THE AREA. A WARM FRONT EXTENDING
EASTWARD FROM A STRONG AREA OF LOW PRESSURE TRACKING INTO THE
GREAT LAKES WILL SURGE NORTHWARD ACROSS OUR AREA ON WEDNESDAY
NIGHT. THIS WILL RESULT IN A RAMP UP IN WARM AIR AND MOISTURE
ADVECTION TO OCCUR. COULD SEE A FEW WARM AIR ADVECTION SHOWERS
OCCUR ESPECIALLY NORTH AND WEST OF THE I- 95 CORRIDOR WITH THE
FRONTAL PASSAGE, BUT OVERALL ANY QPF SHOULD BE LIMITED. LOWS
WILL BE MUCH WARMER THAN THE NIGHT BEFORE WITH LOWS IN THE UPPER
30S TO MID 40S. FOR THURSDAY, WILL HAVE SOME UPPER LEVEL ENERGY
AROUND OFF TO OUR NORTH AND WEST, SO HAVE KEPT A CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS IN THE FORECAST CONTINUING
INTO THURSDAY. CHANCES FOR ANY SEVERE THREAT DO NOT APPEAR TO BE
ALL THAT GREAT WITH BETTER FORCING DISPLACED WELL AWAY FROM THE
AREA. DESPITE MOSTLY CLOUDY TO OVERCAST SKIES AROUND, STRONG
SOUTHERLY WINDS ADVECTING WARMER AIR NORTHWARD SHOULD ALLOW
HIGHS TO RANGE FROM THE UPPER 60S TO UPPER 70S.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
LITTLE IN THE WAY OF CHANGES WERE MADE TO THE LONG TERM PERIOD
AS RIDGING OVER THE EASTERN US WILL BE IN PLACE LATE WEEK
THROUGH THE WEEKEND WITH AN UPPER LEVEL TROUGH MOVING BACK INTO
THE REGION EARLY NEXT WEEK.
LOW PRESSURE EXITS THE REGION THURSDAY NIGHT INTO THE CANADIAN
MARITIMES, WITH A LEFTOVER BOUNDARY REMAINING SITUATED TO THE
NORTH OF OUR AREA. THE BOUNDARY WILL GRADUALLY SINK SOUTHWARD
DURING THE DAY ON FRIDAY INTO FRIDAY NIGHT, WHILE REMAINING WELL
SOUTH OF THE AREA THROUGH THE WEEKEND. SEVERAL WEAK
DISTURBANCES WILL RIDE ALONG THIS BOUNDARY ACCOMPANIED WITH
UPPER LEVEL ENERGY PULSES THAT WILL OCCUR LATE WEEK AND THROUGH
THE WEEKEND. THIS WILL CAUSE A RATHER UNSETTLED WEATHER PERIOD
TO OCCUR LATE IN THE WEEK INTO THE WEEKEND WHERE SEVERAL ROUNDS
OF SHOWERS ARE EXPECTED.
GIVEN THE NATURE OF THE PATTERN, ISOLATED THUNDERSTORMS WILL BE
POSSIBLE FOR THURSDAY NIGHT, BUT NOTHING IN TERMS OF SEVERE
WEATHER IS EXPECTED. A FEW RUMBLES OF THUNDER HERE OR THERE AT
MOST. HEADING INTO FRIDAY THROUGH THE WEEKEND AND INTO EARLY
NEXT WEEK, THE CHANCE FOR THUNDERSTORMS BECOMES LESS LIKELY AS
THE AIRMASS BECOMES MORE STABLE NORTH OF THE BOUNDARY. ALL IN
ALL, HAVE KEPT A CHANCE OF SHOWERS ACROSS THE ENTIRE FORECAST
AREA FRIDAY THROUGH MONDAY. NOT EXPECTING A WASHOUT BY ANY MEANS
AS THERE WILL BE SEVERAL BREAKS/LULLS IN BETWEEN THE ROUNDS OF
SHOWERS, BUT LONG STORY SHORT, IT WILL BE UNSETTLED INTO EARLY
NEXT WEEK.
IN TERMS OF TEMPERATURES, ANOTHER WARM DAY IS TO OCCUR ON
FRIDAY BEFORE THE BOUNDARY PASSES THROUGH THE AREA. WILL BECOME
COOLER OVER THE WEEKEND INTO EARLY NEXT WEEK WITH TEMPERATURES
GENERALLY +/- 5 DEGREES COMPARED TO NORMAL FOR EARLY APRIL.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF OVERNIGHT...RAIN WINDS DOWN WEST TO EAST AS A COLD FRONT
CROSSES THE AREA BUT STILL EXPECT SOME SUB VFR RESTRICTIONS ALONG
AND JUST BEHIND THE FRONT UNTIL THE 7 TO 9Z TIMEFRAME. WINDS
NORTHWEST AROUND 10 TO 15 GUSTING UP TO 25 KNOTS. MODERATE
CONFIDENCE.
TUESDAY...VFR WITH MAINLY CLEAR SKIES AND NW WINDS 10 TO 15 GUSTING
20 TO 25 KNOTS. HIGH CONFIDENCE.
TUESDAY NIGHT...REMAINING VFR WITH WINDS SHIFTING TO NORTHEAST AND
DIMINISHING TO AROUND 5 KNOTS. HIGH CONFIDENCE.
OUTLOOK...
WEDNESDAY...VFR. NO SIGNIFICANT WEATHER EXPECTED.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...MAINLY VFR EXPECTED
WITH OCCASIONAL SUB-VFR CONDITIONS POSSIBLE AT NIGHT. SLIGHT
CHANCE OF RAIN SHOWERS AND AN ISOLATED THUNDERSTORM.
FRIDAY THROUGH SATURDAY...SUB-VFR CONDITIONS POSSIBLE WITH A
CHANCE FOR RAIN SHOWERS.
MARINE
THE SMALL CRAFT ADVISORY CONTINUES UNTIL 1 PM TUESDAY FOR THE
DELAWARE BAY AND 6 PM TUESDAY FOR OUR OCEAN ZONES. FOR THE REST OF
THE OVERNIGHT PERIOD, SW WINDS WILL SHIFT TO NW AROUND 15 TO 20
GUSTING UP TO 30 KNOTS WITH SEAS MAINLY AROUND 5 TO 7 FEET. THESE
CONDITIONS WILL CONTINUE THROUGH TUESDAY MORNING BEFORE GRADUALLY
SUBSIDING AROUND MIDDAY THROUGH THE AFTERNOON.
THE WINDS SHIFT TO NORTHEAST TUESDAY NIGHT BUT THE CONDITIONS SHOULD
BE BELOW SMALL CRAFT ADVISORY LEVELS.
OUTLOOK...
WEDNESDAY...NO MARINE HEADLINES EXPECTED. FAIR WEATHER.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...SCA CONDITIONS
PROBABLE DUE TO WIND GUSTS UP TO 30 KT AND SEAS AROUND 5-7 FEET.
SHOWERS AND ISOLATED THUNDERSTORMS LIKELY.
FRIDAY THROUGH SATURDAY...NO MARINE HEADLINES EXPECTED. PERIODS
OF RAIN SHOWERS LIKELY.
TIDES/COASTAL FLOODING
THE LATEST TWL FCSTS HAVE BEEN ISSUED WITH NO BIG CHANGES FROM
EARLIER. THE ONSHORE WINDS HAVE ELEVATED ASTRONOMICAL TIDES A
LITTLE. THE RECENT NEW MOON COULD LEAD TO SOME SOME SPOTTY MINOR
COASTAL FLOODING WITH TONIGHT'S HIGH TIDE, MAINLY FOR
MIDDLESEX, MONMOUTH, OCEAN COUNTIES, AS WELL AS DELAWARE BAY AND
THE TIDAL DELAWARE RIVER. HOWEVER, ANY IMPACTS ARE ANTICIPATED
TO BE LIMITED AT MOST, AND NO ADVISORIES ARE CURRENTLY
ANTICIPATED.
CLIMATE
LOCALLY HEAVY RAINFALL IS FORECAST ACROSS THE FORECAST AREA TODAY.
BELOW IS A LIST OF THE DAILY PRECIPITATION RECORDS FOR MARCH 31ST.
ALLENTOWN (ABE) 1.80" IN 2022
AC AIRPORT (ACY) 1.46" IN 2017
AC MARINA (55N) 1.22" IN 1958
GEORGETOWN (GED) 1.70" IN 2002
MOUNT POCONO (MPO) 1.41" IN 2022
PHILADELPHIA (PHL) 1.57" IN 1980
READING (RDG) 1.50" IN 1934
TRENTON (TTN) 1.48" IN 1997
WILMINGTON (ILG) 1.75" IN 2017
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EDT THIS AFTERNOON FOR ANZ430-
431.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ450>455.
SYNOPSIS...DESILVA/STAARMANN
NEAR TERM...FITZSIMMONS/MJL
SHORT TERM...DESILVA/STAARMANN
LONG TERM...DESILVA/STAARMANN
AVIATION...DESILVA/FITZSIMMONS/MJL/STAARMANN
MARINE...DESILVA/FITZSIMMONS/MJL
TIDES/COASTAL FLOODING...
CLIMATE...
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