789
FXUS61 KPHI 312339
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
739 PM EDT FRI OCT 31 2025
SYNOPSIS
HIGH PRESSURE WILL BUILD IN BY LATER THIS WEEKEND AS A STRONG
LOW PRESSURE SYSTEM CONTINUES TO PULL AWAY. LOW PRESSURE
DEVELOPS OFF THE MID-ATLANTIC COAST AND MAY BRING SOME IMPACTS
TO PARTS OF THE REGION SUNDAY NIGHT INTO MONDAY. A COLD FRONT
WILL MOVE THROUGH MONDAY NIGHT. HIGH PRESSURE RETURNS THROUGH
MID-WEEK, THEN ANOTHER POTENTIAL STORM SYSTEM APPROACHES THE
AREA WEDNESDAY NIGHT INTO THURSDAY.
NEAR TERM /THROUGH SATURDAY/
A TIGHT PRESSURE GRADIENT REMAINS OVER THE AREA AS STRONG
SURFACE LOW PRESSURE LIES NEAR THE EASTERN CANADA/MAINE BORDER.
A DEEP H5 TROUGH LIES OVER THE NORTHEAST/OHIO VALLEY/MID-
ATLANTIC. A STRONG H5 SHORTWAVE WILL DIVE INTO THE BASE OF THE
TROUGH AND PASS THROUGH THE REGION DURING THE LATE
AFTERNOON/EARLY EVENING HOURS. WITH THIS SHORTWAVE IS A SURGE OF
45 TO 50 KT AT 925-850 MB. THIS WILL KEEP WEST WINDS 15 TO 25
MPH WITH GUSTS UP TO 45 MPH ACROSS THE AREA THIS EVENING. WINDS
WILL DIMINISH FAIRLY QUICKLY OVERNIGHT. A WIND ADVISORY REMAINS
IN EFFECT UNTIL MIDNIGHT, BUT CAN PROBABLY BE CANCELLED EARLIER
THAN THAT.
THIS SHORTWAVE WILL ALSO TRIGGER SOME SPRINKLES ACROSS THE
REGION INTO THIS EVENING, MAINLY IN SOUTHEAST PENNSYLVANIA AND
NORTHERN NEW JERSEY, BUT MEASURABLE PRECIPITATION IS NOT
EXPECTED.
BREEZY THROUGH THE OVERNIGHT HOURS, FINALLY DIMINISHING TO LESS
THAN 10 MPH IN THE PRE-DAWN HOURS. LOWS TONIGHT WILL MOSTLY BE
IN THE LOW TO MID 40S, THOUGH COOLER IN THE SOUTHERN POCONOS AND
A BIT WARMER ALONG THE COASTS DUE TO THE WARMER OCEAN WATERS.
LOW PRESSURE DEPARTS ON SATURDAY AND THE H5 TROUGH IS REPLACED
BY UPPER LEVEL RIDGING ALONG THE COAST. ANOTHER SHORTWAVE WILL
PASS THROUGH THE REGION, AND WHILE IT WILL NOT PRODUCE SHOWERS
OUTSIDE OF A PASSING SPRINKLE OR TWO, MAINLY IN THE SOUTHERN
POCONOS, THERE WILL BE SOME AFTERNOON CLOUDS AND WEST-NORTHWEST
WINDS INCREASING TO 10 TO 20 MPH WITH GUSTS 25 TO 30 MPH. HIGHS
WILL BE IN THE UPPER 50S TO AROUND 60.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/
A LARGE UPPER-TROUGH WILL BE LOCATED OVER CENTRAL AND EASTERN
PORTIONS OF THE US TO START THE PERIOD, WITH A CLOSED LOW
LOCATED OVER PORTIONS OF THE OHIO AND TENNESSEE VALLEYS.
INITIALLY, HIGH PRESSURE WILL BE IN CONTROL AT THE SURFACE
SATURDAY NIGHT THROUGH SUNDAY.
PARTLY TO MOSTLY CLEAR SKIES ARE EXPECTED SATURDAY NIGHT, WITH
VERY LIGHT WINDS. THIS WILL ALLOW FOR VERY EFFECTIVE RADIATIONAL
COOLING AREAWIDE. BELOW FREEZING TEMPERATURES ARE EXPECTED
NORTHWEST OF THE FALL LINE. ACROSS THE REMAINDER OF EASTERN PA
AND NJ, LOWS IN THE MID 30S ARE EXPECTED. FOR COASTAL LOCATIONS,
THE URBAN CORRIDOR, AND THE DELMARVA, UPPER 30S TO NEAR 40 CAN
BE EXPECTED. AREAS OF FROST WILL BE POSSIBLE ACROSS MUCH OF THE
AREA, AND FROST ADVISORIES MAY BE NEEDED IN A FUTURE UPDATE FOR
AREAS IN WHICH THE GROWING SEASON REMAINS ACTIVE.
SUNDAY WILL REMAIN PARTLY TO MOSTLY CLEAR. SOME INCREASE IN
CLOUDS WILL BE POSSIBLE LATE IN THE DAY. AFTERNOON HIGHS WILL BE
SEASONABLY COOL, RANGING FROM THE MID 50S TO LOW 60S ACROSS THE
AREA.
SUNDAY NIGHT INTO MONDAY, THE MID-LEVEL LOW WILL TRACK TOWARDS
THE EASTERN SEABOARD. THE EXACT EVOLUTION OF BOTH UPPER AIR AND
SURFACE FEATURES REMAINS UNCLEAR DUE TO THE POTENTIAL FOR THE
LOW TO BECOME CUT OFF. WITH THAT SAID, MODELS CONTINUE TO
CONVERGE ON A SOLUTION THAT INVOLVES AT LEAST A WEAK AREA OF LOW
PRESSURE DEVELOPING OFF THE MID-ATLANTIC COAST AND TRACKING
NORTHEASTWARD ON MONDAY. MOST MODEL SOLUTIONS HAVE A RELATIVELY
BENIGN EVENT JUST OFFERING SOME RAINFALL TO SOUTHEASTERN
PORTIONS OF THE FORECAST AREA, WHICH SEEMS TO BE THE MOST LIKELY
OUTCOME FOR NOW. REGARDLESS, POPS HAVE COME UP THIS FORECAST
CYCLE, TO 30-40% ACROSS PORTIONS OF THE DELMARVA AND SOUTHERN
NJ. TEMPERATURES LOOK TO REMAIN SEASONABLY COOL DURING THIS
TIME, WITH LOWS SUNDAY NIGHT RANGING FROM THE MID 30S TO LOW 40S
AND HIGHS MONDAY IN THE UPPER 50S TO LOW 60S.
A COLD FRONT WILL PASS THROUGH THE REGION MONDAY NIGHT. WITH
INCREASING MOISTURE AVAILABLE, SHOWERS ARE ALSO POSSIBLE AHEAD
OF AND ALONG THE FRONT BEGINNING MONDAY AFTERNOON AND CONTINUING
INTO THE OVERNIGHT HOURS. THE ENTIRE AREA WILL HAVE A CHANCE TO
SEE SOME RAIN, THOUGH AMOUNTS CONTINUE TO LOOK LIGHT. THE FRONT
WILL USHER IN AIR THAT'S NOTABLY DRIER, BUT NOT NECESSARILY
NOTABLY COOLER. LOWS MONDAY NIGHT WILL GENERALLY BE IN THE LOW
40S.
LONG TERM /TUESDAY THROUGH FRIDAY/
THE PASSAGE OF THE COLD FRONT MONDAY NIGHT WILL BRING TRANQUIL
CONDITIONS TO THE REGION THROUGH MID-WEEK. NORTHWESTERLY FLOW
ALOFT TO START THE PERIOD WILL CONTINUE THROUGH WEDNESDAY, WHEN
A SHORTWAVE IS ANTICIPATED TO BEGIN APPROACHING FROM THE
NORTHWEST. AT THE SURFACE, STRONG HIGH PRESSURE WILL SHIFT
EASTWARD FROM THE TENNESSEE VALLEY INTO PORTIONS OF THE MID-
ATLANTIC.
TUESDAY THROUGH MOST OF WEDNESDAY SHOULD FEATURE MOSTLY CLEAR
SKIES AND SEASONABLE TEMPERATURES. A BREEZY NORTHWEST WIND IS
EXPECTED DURING THE DAY ON TUESDAY, DIMINISHING TUESDAY NIGHT.
CLOUDS MAY BEGIN TO INCREASE ACROSS THE AREA BY WEDNESDAY
AFTERNOON AS THE NEXT SYSTEM APPROACHES.
A SHORTWAVE AXIS IS EXPECTED TO MOVE SOUTHEASTWARD THROUGH THE
AREA WEDNESDAY NIGHT, FOLLOWED BY HEIGHT RISES ALOFT THROUGH THE
END OF THE WEEK. AT THE SURFACE, LOW PRESSURE AND AN ASSOCIATED
COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY NIGHT INTO
THURSDAY, WITH HIGH PRESSURE BUILDING IN BEHIND IT.
WEDNESDAY NIGHT INTO THURSDAY, THERE WILL BE A CHANCE FOR MORE
RAIN, WITH THE HIGHEST CHANCES ACROSS THE NORTHERN HALF OR SO OF
THE AREA. THIS LOOKS LIKE A RELATIVELY QUICK HITTING SYSTEM,
AGAIN WITH RAIN AMOUNTS REMAINING LIGHT. TEMPERATURES WEDNESDAY
NIGHT INTO THURSDAY SHOULD BE SEASONABLE, WITH BELOW NORMAL
TEMPERATURES POSSIBLE ON FRIDAY AFTER THE SYSTEM HAS PASSED.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. WESTERLY WINDS 15-20 KNOTS WITH GUSTS UP TO 30
KNOTS, DIMINISHING TO AROUND 10 KNOTS AFTER ABOUT 06Z. HIGH
CONFIDENCE.
SATURDAY...VFR. WEST TO WEST-NORTHWEST WINDS 10-15 KNOTS WITH
GUSTS TO 20-25 KNOTS. THE WINDS SHOULD THEN DIMINISH TOWARD MID
TO LATE AFTERNOON. MODERATE CONFIDENCE.
OUTLOOK...
SATURDAY NIGHT THROUGH SUNDAY...VFR. NO SIGNIFICANT WEATHER.
SUNDAY NIGHT THROUGH MONDAY NIGHT...PRIMARILY VFR. PERIODS OF
SUB- VFR CONDITIONS CAN'T BE RULED OUT WITH A CHANCE FOR RAIN
(30-40%).
TUESDAY THROUGH WEDNESDAY...VFR. GUSTY WEST TO NORTHWEST WIND
ON TUESDAY.
MARINE
GALE WARNINGS REMAIN IN EFFECT THROUGH TONIGHT FOR MOST OF THE
WATERS WITH WEST WINDS 20 TO 30 KT WITH 35 TO 45 KT GUSTS. GUSTS
WILL DIMINISH TO LESS THAN 35 KT ON DELAWARE BAY AND THE OCEAN
WATERS FROM CAPE HENLOPEN TO FENWICK ISLAND DE AFTER MIDNIGHT
TONIGHT. FOR THE REST OF THE OCEAN WATERS, GALES SHOULD CONTINUE
INTO THE PRE-DAWN HOURS.
A SMALL CRAFT ADVISORY WILL BE NEEDED AFTER THE GALE WARNINGS
END, AS WEST WINDS WILL AVERAGE 15 TO 20 KT WITH 25 KT GUSTS
INTO SATURDAY AFTERNOON. SEAS WILL AVERAGE 8 TO 12 FEET ON THE
OCEAN TONIGHT BEFORE SUBSIDING TO 3 TO 5 FEET ON SATURDAY.
OUTLOOK...
SATURDAY NIGHT THROUGH SUNDAY NIGHT...NO MARINE HEADLINES ARE
ANTICIPATED WITH WINDS BELOW 25 KT AND SEAS BELOW 5 FEET.
MONDAY THROUGH TUESDAY NIGHT...SCA CONDITIONS ARE LIKELY AT
TIMES. WHILE NOT LIKELY OR CURRENTLY EXPLICITLY FORECAST, IT IS
POSSIBLE THE WINDS AND SEAS COULD BE ELEVATED ON MONDAY WITH THE
DEVELOPMENT OF LOW PRESSURE OFF THE MID-ATLANTIC COAST. LATE
MONDAY NIGHT THROUGH TUESDAY NIGHT, A COLD FRONTAL PASSAGE IS
EXPECTED TO LEAD TO STRONG WEST OR NORTHWEST WINDS 20-30 KT AND
SEAS 4-5 FEET.
WEDNESDAY...NO MARINE HEADLINES ARE ANTICIPATED WITH WINDS
BELOW 25 KT AND SEAS BELOW 5 FEET.
PHI WATCHES/WARNINGS/ADVISORIES
PA...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR PAZ054-055-
060>062-070-071-101>106.
NJ...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NJZ001-007>010-
012>027.
DE...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DEZ001>004.
MD...NONE.
MARINE...GALE WARNING UNTIL 2 AM EDT SATURDAY FOR ANZ430-431-455.
GALE WARNING UNTIL 6 AM EDT SATURDAY FOR ANZ450>454.
SYNOPSIS...AKL/COOPER
NEAR TERM...MPS
SHORT TERM...COOPER
LONG TERM...COOPER
AVIATION...COOPER/GORSE/MPS
MARINE...COOPER/MPS
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