721
FXUS61 KPHI 310550
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
150 AM EDT MON AUG 31 2026
WHAT HAS CHANGED
UPDATED AVIATION SECTION FOR 06Z TAFS.
KEY MESSAGES
1. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS
PORTIONS OF EASTERN PENNSYLVANIA AND NEW JERSEY OVERNIGHT.
2. HEAT AND HUMIDITY WILL BUILD INTO THE MIDDLE OF THE WEEK,
ALONG WITH DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS. THERE IS
AN INCREASING THREAT OF SEVERE THUNDERSTORMS AND POTENTIALLY
FLASH FLOODING DURING THE MIDDLE OF THE WEEK, NAMELY TUESDAY
THROUGH THURSDAY.
DISCUSSION
KEY MESSAGE 1...SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS PORTIONS OF EASTERN PENNSYLVANIA AND NEW JERSEY
OVERNIGHT.
THERE HAS BEEN SOME MODEST DESTABILIZATION THAT HAS OCCURRED
INTO THIS EVENING WITH ML CAPES AROUND 500-1500 ACROSS THE HEART
OF THE CWA. AND AS AN UPPER LEVEL DISTURBANCE PIVOTS THROUGH
FROM THE NORTH AND WEST, THIS HAS INITIATED SOME SHOWERS AND
STORMS THIS PAST EVENING INTO THE EARLY PART OF THE OVERNIGHT.
LOCALLY HEAVY RAINFALL IS POSSIBLE WITH THE STRONGEST STORMS.
SOME LOCALIZED FLOODING CAN'T BE RULED OUT ESPECIALLY IN AREAS
THAT HAVE RECEIVED SUBSTANTIAL RAINFALL RECENTLY. HOWEVER,
OVERALL THIS POTENTIAL IS EXPECTED TO REMAIN FAIRLY LIMITED. WPC
HAS PLACED EASTERN PA AND NJ UNDER A MARGINAL RISK (1 OF 4) FOR
EXCESSIVE RAINFALL. THE THREAT FOR SEVERE THUNDERSTORMS IS LOW,
THOUGH A FEW INSTANCES OF GUSTY WINDS OR SMALL HAIL WILL BE
POSSIBLE WITH THE STRONGEST STORMS.
SCATTERED SHOWERS MAY PERSIST WELL INTO THE OVERNIGHT HOURS AS
FORCING REMAINS ALOFT.
KEY MESSAGE 2...HEAT AND HUMIDITY WILL BUILD INTO THE MIDDLE OF
THE WEEK, ALONG WITH DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS. THERE IS AN INCREASING THREAT OF SEVERE
THUNDERSTORMS AND POTENTIALLY FLASH FLOODING DURING THE MIDDLE
OF THE WEEK, NAMELY TUESDAY THROUGH THURSDAY.
BROAD UPPER LEVEL RIDGING RETURNS TO THE EASTERN US EARLY NEXT
WEEK, BRINGING IN SURFACE HIGH PRESSURE ACROSS THE EASTERN US.
AFTERNOON HIGHS WILL CREEP BACK INTO THE MID 80S TO LOW 90S FOR
MOST AREAS, ABOUT 5 DEGREES ABOVE AVERAGE FOR EARLY SEPTEMBER.
DEWPOINTS WILL ALSO REMAIN IN THE UPPER 60S TO LOW 70S. THE
HOTTEST DAY LOOKS TO BE TUESDAY, WHEN HIGH TEMPERATURES COULD
GET INTO THE MID 90S ACROSS DELMARVA AND INTO THE PHILLY METRO.
RESULTING HEAT INDICES WILL BE WELL INTO THE 90S TO AROUND 100.
WE WILL CONTINUE TO KEEP AN EYE ON THE POTENTIAL FOR HEAT
ADVISORIES.
ONE OTHER ASPECT TO WATCH WITH THIS RIDGING PATTERN IS THE
POTENTIAL FOR THUNDERSTORMS TO ROTATE AROUND THE PERIPHERY OF
THE RIDGE AND THE POSITION OF A FRONTAL BOUNDARY DURING THE
MIDDLE OF THE WEEK. LATEST GUIDANCE SUGGESTS THAT MONDAY MAY BE
MOSTLY DRY, THOUGH ISOLATED STORMS CAN'T BE RULED OUT. GUIDANCE
CONTINUES TO COME INTO CONSENSUS THAT THE PATTERN WILL BE
SUPPORTIVE OF MULTIPLE ROUNDS OF THUNDERSTORMS, ESPECIALLY
DURING THE TUESDAY THROUGH THURSDAY TIME FRAME.
SPC HAS PLACED PORTIONS OF THE AREA IN A SLIGHT RISK (2 OF 5)
FOR SEVERE THUNDERSTORMS TUESDAY. WEDNESDAY AND THURSDAY ARE
ALSO HIGHLIGHTED WITH 15% PROBABILITIES FOR SEVERE
THUNDERSTORMS. THE NORTHWEST FLOW PATTERN THAT WILL BE IN PLACE
WILL BE SUPPORTIVE OF ALL SEVERE THREATS, INCLUDING DAMAGING
WINDS, LARGE HAIL, AND TORNADOES. THE THREAT FOR FLASH FLOODING
IS TYPICALLY LOWER WITH THESE PATTERNS, HOWEVER GIVEN MULTIPLE
DAYS WITH THE POTENTIAL FOR STORMS AND RECENT HEAVY RAINFALLS,
AT LEAST SOME RISK FOR FLASH FLOODING WILL EXIST. LONG STORY
SHORT, THE TUESDAY THROUGH THURSDAY PERIOD LOOKS VERY ACTIVE
WITH MULTIPLE ROUNDS OF THUNDERSTORMS ACROSS THE REGION, BUT
DETAILS REMAIN UNCLEAR. STAY TUNED FOR UPDATES ON THESE THREATS
OVER THE COMING DAYS.
BY FRIDAY, CURRENT MODEL CONSENSUS INDICATES THE FRONTAL
BOUNDARY WILL BE PUSHING SOUTH OF OUR REGION WITH CANADIAN HIGH
PRESSURE BUILDING ACROSS THE NORTHEAST. THIS SHOULD FAVOR AN END
TO SEVERE WEATHER AND FLASH FLOODING POTENTIAL.
AVIATION /06Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...A FEW SHOWERS AND STORMS WILL BE NEAR ILG/MIV/ACY.
THE POTENTIAL FOR MVFR CEILINGS DEVELOPING HAS DIMINISHED, AND
THUS REMOVED FROM THE TAFS WITH THIS UPDATE. LIGHT AND VARIABLE
WINDS, SETTLING OUT OF THE NORTHEAST OR EAST 5 KTS OR LESS
TOWARD 12Z. LOW CONFIDENCE IN THE MVFR RESTRICTIONS.
MONDAY...PREVAILING VFR CONDITIONS EXPECTED. NORTHEAST WINDS IN
THE MORNING AROUND 5 KT, SHIFTING TO A MORE SOUTH TO
SOUTHEASTERLY DIRECTION BY 18Z. THERE IS A LOW (GENERALLY LESS
THAN 20%) CHANCE FOR ISOLATED SHOWERS OR STORMS WHICH COULD
CAUSE BRIEF RESTRICTIONS IN THE AFTERNOON. MODERATE CONFIDENCE.
MONDAY NIGHT...MVFR CEILINGS LIKELY DEVELOPING BY 06Z. SCATTERED
SHOWERS AROUND AT TIMES, AND VISIBILITY ARE UNLIKELY OUTSIDE OF
ANY BRIEF RAIN SHOWERS. WINDS SETTLING OUT OF THE SOUTH TO
SOUTHWEST AROUND 5 KTS OR LESS. MODERATE CONFIDENCE.
OUTLOOK...
TUESDAY THROUGH THURSDAY...RESTRICTIONS POSSIBLE IN SHOWERS AND
THUNDERSTORMS EACH DAY, MAINLY DURING THE AFTERNOON TO EVENING
HOURS.
FRIDAY...PRIMARILY VFR.
MARINE
NO PREVAILING MARINE HAZARDS EXPECTED. SOUTH-SOUTHWESTERLY
WINDS OF 10-15 KTS INTO THE FIRST PART OF TONIGHT, WITH WINDS
TURNING MORE WESTERLY AND DIMINISHING LATE. EAST TO EAST-
SOUTHEAST WINDS MONDAY AROUND 5-10 KTS. SEAS 2-3 FEET. SHOWERS
AND STORMS ARE POSSIBLE BEGINNING THIS EVENING. GENERALLY FAIR
WEATHER MONDAY.
OUTLOOK...
MONDAY NIGHT THROUGH FRIDAY...NO PREVAILING MARINE HAZARDS
EXPECTED. CHANCES FOR THUNDERSTORMS EACH DAY, MAINLY IN THE
AFTERNOON AND EVENING HOURS.
RIP CURRENTS...
FOR MONDAY, NORTH TO NORTHWEST WINDS IN THE MORNING WILL SHIFT
TO EAST IN THE AFTERNOON AROUND 5 MPH. BREAKING WAVE HEIGHTS
AROUND 1 FOOT. A LIGHT SOUTHEASTERLY SWELL WITH A PERIOD AROUND
8 SECONDS WILL REMAIN. THIS WILL CONTINUE TO LEAD TO A LOW RISK
FOR THE DEVELOPMENT OF DANGEROUS AND LIFE THREATENING RIP
CURRENTS AT THE JERSEY SHORE AND DELAWARE BEACHES.
FOR TUESDAY, SOUTH/SOUTHWEST WINDS WILL INCREASE SOME TO AROUND
10 TO 15 MPH BUT THEY LITTLE CHANGE IS EXPECTED SO WE'LL
CONTINUE WITH A LOW RISK FOR THE DEVELOPMENT OF DANGEROUS RIP
CURRENTS AT THE JERSEY SHORE AND DELAWARE BEACHES.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
DISCUSSION...AS/WFO PHI
AVIATION...AS/WFO PHI
MARINE...AS/WFO PHI
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