630
FXUS61 KPHI 272354
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
754 PM EDT SUN APR 27 2025
SYNOPSIS
HIGH PRESSURE OVER THE GREAT LAKES BUILDS INTO THE REGION TONIGHT,
BEFORE SHIFTING TO OUR SOUTH AND EAST ON MONDAY AND INTO MONDAY
NIGHT. A WARM FRONT ARRIVES ON TUESDAY, FOLLOWED BY A COLD FRONT BY
WEDNESDAY MORNING. HIGH PRESSURE BRIEFLY RETURNS FOR WEDNESDAY NIGHT
INTO THURSDAY. ANOTHER LOW PRESSURE SYSTEM TRACKS TO OUR NORTH ON
FRIDAY WITH A COLD FRONT CROSSING THROUGH EARLY ON SATURDAY. HIGH
PRESSURE BUILDS BACK IN BY SUNDAY.
NEAR TERM /THROUGH MONDAY/
AS OF 715 PM, MADE SOME MINOR ADJUSTMENTS TO THE HOURLY WIND
FORECAST AS SOME GUSTS AROUND 25 MPH CONTINUE TO OCCUR ACROSS
THE AREA. THE WIND WILL QUICKLY SUBSIDE AFTER SUNSET. NO OTHER
CHANGES WERE MADE.
AN UPPER TROUGH WITH SHORTWAVE ENERGY OVER THE NORTHEAST
WILL DEPART AS SURFACE LOW PRESSURE OVER EASTERN CANADA TRACKS
EAST AND INTO THE WESTERN ATLANTIC OCEAN WATERS. MEANWHILE,
SURFACE HIGH PRESSURE CENTERED OVER THE GREAT LAKES AND OHIO
VALLEY WILL BUILD EAST, AND WILL BE CENTERED OVER THE
APPALACHIANS BY MONDAY MORNING, THEN WILL BE OFF THE MID-
ATLANTIC AND DELMARVA PENINSULA COASTS BY MONDAY AFTERNOON.
SKIES WILL BE CLEAR TONIGHT AND SUNNY ON MONDAY WITH STRONG
SUBSIDENCE OVER THE AREA.
WINDS BECOME NORTH TO NORTHWEST BY MIDNIGHT OR SO, AT GENERALLY
5 MPH OR LESS. WITH CLEAR SKIES AND LIGHT WINDS, CAN EXPECT
DECENT RADIATIONAL COOLING CONDITIONS TO DEVELOP IN THE FAVORED
AREAS AWAY FROM THE URBAN CENTERS. LOWS TONIGHT WILL GENERALLY
BE IN THE 40S, AND WILL BE AT OR SEVERAL DEGREES BELOW NORMAL
FOR THIS TIME OF THE YEAR.
WINDS BECOME VARIABLE MONDAY MORNING, THEN TAKE ON A SOUTHWEST FLOW
AT 5 TO 10 MPH INLAND, AND THEN SEA BREEZES WILL DEVELOP NEAR THE
COASTS AND WILL TRACK AS FAR WEST AS THE I-95 CORRIDOR. BEHIND THE
SEA BREEZE, WINDS WILL BE SOUTH AT 5 TO 10 MPH.
TEMPERATURES RETURN TO ABOVE NORMAL LEVELS AS RETURN FLOW SETS UP.
HIGHS WILL BE IN THE LOW TO MID 70S, WHICH ARE SEVERAL DEGREES ABOVE
THE SEASONAL AVERAGE FOR THIS TIME OF THE YEAR.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
UPPER LEVEL RIDGE CONTINUES TO BUILD OVER THE AREA ON MONDAY NIGHT
BEFORE THE RIDGE AXIS CROSSES THROUGH ON TUESDAY. UPPER FLOW THEN
BECOMES MOSTLY ZONAL THROUGH WEDNESDAY AS AN UPPER TROUGH PASSES
WELL TO OUR NORTH ACROSS CANADA. AT THE SURFACE, HIGH PRESSURE WILL
BE LOCATED OFF THE MID-ATLANTIC COAST THROUGH TUESDAY WITH THE
RETURN OF SOUTHERLY FLOW. A WARM FRONT WILL LIFT NORTH OF THE AREA
LATE ON TUESDAY, FOLLOWED BY A COLD FRONT ON WEDNESDAY THAT WILL
EVENTUALLY STALL OVER THE DELMARVA.
CLEAR/SUNNY SKIES ARE EXPECTED FOR MONDAY NIGHT INTO THE FIRST HALF
OF TUESDAY, BEFORE CLOUDS INCREASE AHEAD OF APPROACHING FRONTAL
SYSTEM. LIGHT SOUTHERLY FLOW WILL KEEP TEMPS AT BAY FOR MONDAY NIGHT
WITH LOWS IN THE MID 40S TO LOW 50S. WILL BEGIN TO SEE SOME STRONGER
SOUTHERLY BREEZES ON TUESDAY UPWARDS OF 25 MPH WHICH WILL HELP
ADVECT WARMER AIR FURTHER NORTH. HIGH TEMPERATURES SHOULD TOP OUT IN
THE MID 70S TO LOW 80S. BY TUESDAY NIGHT, A WARM FRONT WILL BE
LIFTING NORTH OF THE AREA ALLOWING DEW POINTS TO RISE FROM THE 40S
INTO THE 50S. IN ADDITION TO THE INCREASE IN MOISTURE AND CLOUD
COVER, THIS WILL KEEP TEMPERATURES VERY MILD FOR TUESDAY NIGHT AS WE
AWAIT THE COLD FRONTAL PASSAGE EARLY WEDNESDAY. THERE STILL LOOKS TO
BE SOME CHANCE FOR SHOWERS TUESDAY NIGHT, ESPECIALLY UP IN THE
POCONOS, THEREFORE KEPT THE MENTION OF SLIGHT CHANCE TO LOW CHANCE
POPS (20-30%). AS PER THE LATEST SPC OUTLOOK FOR DAY 3, A MARGINAL
RISK HAS BEEN ADDED FOR THE POCONOS FOR TUESDAY-TUESDAY NIGHT. FOR
WEDNESDAY, THE FRONT WILL CROSS THROUGH MUCH OF THE REGION BEFORE
'WASHING OUT' AND STALLING AROUND THE DELMARVA. THE AIRMASS BEHIND
THE FRONT REALLY LACKS ANY COLD AIR BEHIND IT, INSTEAD IT WILL KNOCK
DEW POINTS DOWN. IN WAKE OF THE FRONT, A DRY WEST-NORTHWEST BREEZE
WILL BE IN PLACE WITH HIGHS IN THE MID 70S TO LOW 80S, ALTHOUGH 60S
IN THE HIGHER ELEVATIONS. OVERALL, A BENIGN BUT WARM WEATHER PERIOD
IS IN STORE FOR THE SHORT TERM.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
SUMMARY...MILD TO WARM TEMPERATURES WITH A COUPLE CHANCES FOR
SHOWERS AND/OR THUNDERSTORMS.
SYNOPTIC OVERVIEW...A BRIEF MID/UPPER RIDGE BUILDS OVERHEAD ON
THURSDAY FOLLOWED QUICKLY BY ANOTHER UPPER-LEVEL TROUGH ON FRIDAY
WHICH WILL CLOSE OFF AND SETTLE OVER NORTHERN NEW ENGLAND THROUGH
SUNDAY. AT THE SURFACE, HIGH PRESSURE TEMPORARILY BUILDS IN FOR
WEDNESDAY NIGHT AS IT SLIDES BY TO OUR NORTH ON THURSDAY. LOW
PRESSURE TRACKS INTO SOUTHERN CANADA ON FRIDAY WITH A COLD FRONT
CROSSING THROUGH THE AREA LATE FRIDAY NIGHT INTO SATURDAY. HIGH
PRESSURE THEN RETURNS FOR THE SECOND HALF OF THE WEEKEND.
FOR WEDNESDAY NIGHT AND THURSDAY...THE STALLED FRONTAL BOUNDARY WILL
START TO LIFT BACK NORTHWARD WEDNESDAY NIGHT AS A WARM FRONT AND
SOME SHOWERS COULD DEVELOP IN ADVANCE OF THAT, HOWEVER CHANCES ARE
LOW AT THIS POINT. SURFACE HIGH PRESSURE IS FORECAST TO SLIDE BY TO
OUR NORTH ON THURSDAY. AS THE FLOW VEERS FROM SOUTHEAST TO
SOUTHWEST, WARM AIR ADVECTION GETS UNDERWAY ESPECIALLY AS A WARM
FRONT ARRIVES. LOWS WILL BE IN THE 40S/50S WITH HIGHS IN THE UPPER
60S TO UPPER 70S.
FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE INCREASING ISENTROPIC
LIFT IN ADVANCE OF AN APPROACHING UPPER-LEVEL TROUGH MAY RESULT IN
SOME SHOWERS LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT. AT LEAST
SOME ELEVATED INSTABILITY CANNOT BE RULED OUT. THE AFOREMENTIONED
UPPER-LEVEL TROUGH DRIVES SURFACE LOW PRESSURE ACROSS THE GREAT
LAKES AND SOUTHERN CANADA ON FRIDAY, AND THIS PULLS A COLD FRONT
ACROSS OUR AREA FOR FRIDAY NIGHT. INCREASING FORCING FOR ASCENT TIED
TO THIS INCOMING UPPER-LEVEL TROUGH AND COLD FRONT SHOULD RESULT IN
AN INCREASE IN SHOWERS FOR A TIME. SOME THUNDER IS POSSIBLE GIVEN
ENOUGH INSTABILITY AS OUR REGION IS FORECAST TO BE IN THE WARM
SECTOR ALONG WITH MORE HUMID CONDITIONS. TEMPERATURES WILL BE VERY
MILD WITH HIGHS ON FRIDAY IN THE UPPER 70S TO MID 80S WITH LOWS AT
NIGHT IN THE 50S/60S.
FOR SATURDAY AND SUNDAY...IN WAKE OF THE COLD FRONT, WARM
TEMPERATURES WILL COOL SOME OVER THE WEEKEND AND RETURN BACK TO NEAR-
NORMAL LEVELS WITH MOSTLY DRY CONDITIONS.
AVIATION /00Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR/SKC. NW WIND AROUND 15 KT WITH GUSTS AROUND 25
KT, DIMINISHING TO LESS THAN 10 KT AFTER 01Z, THEN TO 5 KT OR
LESS AFTER 06Z. HIGH CONFIDENCE.
MONDAY...VFR/SKC. LIGHT N-NW WINDS IN THE MORNING, EVENTUALLY
TURNING SW AROUND 5 KT NEAR/AFTER 18Z. SEA BREEZES MAY AFFECT
KACY AND KMIV IN THE AFTERNOON, AND A BAY BREEZE MAY AFFECT KILG
IN THE AFTERNOON. HIGH CONFIDENCE.
OUTLOOK...
MONDAY NIGHT THROUGH WEDNESDAY...VFR. A SLIGHT CHANCE OF A RAIN
SHOWER OR THUNDERSTORM ON TUESDAY NIGHT AT KRDG/KABE, OTHERWISE, NO
SIGNIFICANT WEATHER EXPECTED.
WEDNESDAY NIGHT THROUGH THURSDAY...VFR. NO SIGNIFICANT WEATHER
EXPECTED.
THURSDAY NIGHT THROUGH FRIDAY...SUB-VFR CONDITIONS POSSIBLE WITH
SCATTERED SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM.
MARINE
SMALL CRAFT ADVISORY HAS BEEN ALLOWED TO EXPIRE. SUB- SCA
CONDITIONS FOR THE REMAINDER OF TONIGHT. WINDS DIMINISH TO 10
TO 15 KT WITH GUSTS UP TO 20 KT. LIGHT N WINDS MONDAY MORNING
WILL TURN S AROUND 10 KT MONDAY AFTERNOON. SEAS WILL AVERAGE 2
TO 3 FT.
OUTLOOK...
MONDAY NIGHT...NO MARINE HEADLINES EXPECTED. FAIR WEATHER.
TUESDAY THROUGH TUESDAY NIGHT...SCA CONDITIONS LIKELY ESPECIALLY IN
THE LATE AFTERNOON AND EVENING DUE TO WIND GUSTS AROUND 25 KT AND
SEAS AROUND 4-6 FEET. FAIR WEATHER OUTSIDE OF SCA CONDITIONS.
WEDNESDAY THROUGH THURSDAY NIGHT...NO MARINE HEADLINES EXPECTED.
FAIR WEATHER THROUGH THURSDAY WITH A CHANCE FOR SHOWERS AND
THUNDERSTORMS ON THURSDAY NIGHT.
FRIDAY...SCA CONDITIONS POSSIBLE DUE TO SEAS AROUND 5 FEET. A CHANCE
FOR RAIN SHOWERS.
FIRE WEATHER
CONDITIONS WILL BE MUCH DRIER ON MONDAY, BUT WINDS WILL BE MUCH
LIGHTER AS WELL. MIN RH VALUES WILL BE 20 TO 25 PERCENT. LIGHT
NORTH WINDS MONDAY MORNING WILL BECOME VARIABLE, EVENTUALLY
TURNING SOUTHWEST AT 5 TO 10 MPH IN THE AFTERNOON. SEA BREEZES
MAY DEVELOP NEAR COASTAL AREAS AS WELL, WITH SPEEDS 5 TO 10 MPH.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ430-
431-450>455.
SYNOPSIS...DESILVA
NEAR TERM...COOPER/MPS
SHORT TERM...DESILVA/GORSE
LONG TERM...DESILVA/GORSE
AVIATION...COOPER/DESILVA/MPS
MARINE...COOPER/DESILVA/MPS
FIRE WEATHER...PHI
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