931
FXUS61 KPHI 091724
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
124 PM EDT WED JUL 9 2025
SYNOPSIS
A SLOW MOVING FRONTAL BOUNDARY WILL WAFFLE ACROSS THE MID-
ATLANTIC THROUGH LATE WEEK AS ADDITIONAL DISTURBANCES MOVE
THROUGH. BERMUDA HIGH PRESSURE WILL BE IN PLACE THROUGH THE
WEEKEND, EVENTUALLY BREAKING DOWN FOR THE START OF THE NEW WORK
WEEK. SEVERAL DISTURBANCES WILL PASS THROUGH OVER THE WEEKEND AS
WELL.
NEAR TERM /THROUGH TONIGHT/
TODAY, WILL VIRTUALLY BE A RINSE AND REPEAT KIND OF DAY IN
TERMS OF THE OVERALL FORECAST, EXCEPT THE FRONTAL BOUNDARY IS A
LITTLE FARTHER SOUTH, SUPPRESSING THE OVERALL THREAT OF
CONVECTION A BIT FURTHER SOUTH. PARTLY CLOUDY SKIES IN THE
MORNING WILL GIVE WAY TO MOSTLY CLOUDY SKIES THIS AFTERNOON.
WITH THE TROPICAL AND DEEP MOISTURE AIRMASS PERSISTING IN
ADDITION TO THE NEARBY FRONTAL BOUNDARY, YET ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WILL DEVELOP AROUND LATE AFTERNOON
TODAY. GREATEST THREAT WILL BE FROM PHILADELPHIA ON SOUTH, WHERE
BETTER ATMOSPHERIC PARAMETERS OVERLAP WITH ONE ANOTHER, SO SPC
HAS A SLIGHT RISK IN THOSE AREAS, WITH A MARGINAL RISK REMAINING
ELSEWHERE. SIMILARLY, WPC HAS KEPT A SLIGHT RISK FOR EXCESSIVE
RAINFALL FOR MOST OF THE AREA ON WEDNESDAY, HOWEVER HAS
INTRODUCED A MODERATE RISK FOR EXCESSIVE RAINFALL AROUND
PHILADELPHIA AND WILMINGTON AND THE SURROUNDING SUBURBS. A FLOOD
WATCH FOR FLASH FLOODING IS IN EFFECT THAT BASICALLY INCLUDES
ALL AREAS FROM THE I-78 CORRIDOR SOUTHWARD. COMPARED TO TUESDAY,
THE TIMING OF THE CONVECTION WILL BE A BIT LATER...MAINLY AFTER
5 PM SO THE FLOOD WATCH WILL BEGIN AT THIS TIME. ALL IN ALL
ANOTHER MUGGY AND HUMID DAY IS EXPECTED. TEMPERATURES WILL BE A
FEW DEGREES COOLER DUE TO MORE CLOUD COVER COMPARED TO TODAY
WHERE HEAT INDICIES WILL LARGELY REMAIN IN THE 90S FOR THE
MAJORITY OF THE AREA. SO IT LOOKS LIKE WE'LL FALL SHORT OF
NEEDING ANY HEAT HEADLINES.
SHOWERS AND STORMS CONTINUE THIS EVENING WITH THE SEVERE THREAT
GRADUALLY DIMINISHING WITH TIME BUT THE FLASH FLOOD THREAT
PERSISTING AT LEAST THROUGH THE EVENING PERIOD. PWATS WILL
REMAIN AROUND 2 INCHES MEANING HEAVY DOWNPOURS WILL BE CAPABLE
OF PRODUCING LOCALLY 2-3 INCHES OF RAIN WITHIN A 1 TO 3 HOUR
TIMEFRAME. SHOWERS/STORMS ARE LIKELY TO LINGER OVERNIGHT NEAR
AND SOUTH OF THE URBAN CORRIDOR HOWEVER THE INTENSITY OF THEM
AND ASSOCIATED RAINFALL RATES SHOULD DIMINISH. THE FLOOD WATCH
RUNS UNTIL 2 AM. LOWS BY THURSDAY MORNING SHOULD BE MAINLY IN
THE UPPER 60S TO LOW 70S.
SHORT TERM /THURSDAY THROUGH FRIDAY/
A WARM AND HUMID AIRMASS WILL BE OVER THE NORTHEAST AND MID-
ATLANTIC FOR THE SHORT TERM PERIOD. SURFACE DEW POINTS WILL BE IN
THE LOW TO MID 70S, ALONG WITH HIGHS GENERALLY IN THE MID 80S. THIS
WILL YIELD HEAT INDEX VALUES IN THE LOW TO MID 90S. THESE HIGH DEW
POINTS WILL ALSO KEEP LOW TEMPERATURES AT NIGHT QUITE WARM, AND LOWS
WILL GENERALLY BE IN THE LOWER 70S.
UNSETTLED WEATHER WILL REMAIN ON TAP AS A FRONTAL BOUNDARY WILL
HOVER OVER THE AREA. ABUNDANT LOW LEVEL MOISTURE WILL BE IN PLACE
GIVEN THOSE HIGH DEW POINTS, AND PWATS WILL BE UP TO AND IN EXCESS
OF 2 INCHES.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL IMPACT THE AREA
THURSDAY AFTERNOON AND EVENING AS SHORTWAVE ENERGY APPROACHES FROM
THE WEST AND PASSES THROUGH THE REGION. GIVEN HOW WARM AND HUMID
CONDITIONS WILL BE, LOCALLY HEAVY RAIN AND DAMAGING WIND GUSTS ARE
POSSIBLE ONCE AGAIN. THIS PATTERN WILL REPEAT YET AGAIN ON FRIDAY.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
A FAIRLY TYPICAL SUMMERTIME PATTERN IS ON TAP FOR THE LONG TERM
PERIOD WITH WARM AND VERY HUMID CONDITIONS. SURFACE DEW POINTS WILL
GENERALLY BE IN THE LOW TO MID 70S THOUGH IT IS POSSIBLE THAT DURING
THE PEAK HEATING OF THE DAY DEW POINTS DROP BY A FEW DEGREES DUE TO
MIXING. HIGHS WILL GENERALLY BE IN THE MID TO UPPER 80S, POSSIBLY
AROUND 90 IN SOME SPOTS. THIS WILL GIVE WAY TO MAX HEAT INDEX VALUES
GENERALLY IN THE LOW TO MID 90S.
A SERIES OF DISTURBANCES WILL PASS THROUGH THE REGION FROM TIME TO
TIME, BUT CONFIDENCE IN TIMING AND PLACEMENT IS LOW. WILL GENERALLY
FOLLOW THE NBM AND GO WITH 30 TO 50 PERCENT POPS FOR MOST OF THIS
TIME, THOUGH THE NBM IS INDICATING 60 PERCENT POPS FOR THE SOUTHERN
POCONOS, LEHIGH VALLEY, AND BERKS COUNTY ON SUNDAY DUE TO A STRONGER
SYSTEM POSSIBLY APPROACHING THEN. IMPORTANT TO NOTE THAT ANY SHOWERS
AND THUNDERSTORMS WILL MOSTLY BE IN THE AFTERNOON AND EVENING HOURS
AND THERE ARE NOT MANY FACTORS INDICATING PRECIPITATION WOULD BE
WIDESPREAD AND ORGANIZED AT THIS TIME.
AVIATION /17Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON...VFR EXPECTED FOR THE REMAINDER OF THE DAY WITH
SOUTHWEST WINDS AROUND 5-10 KT. ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO MOVE IN LATE IN THE DAY, GENERALLY
AFTER 20-21Z FOR KRDG/KABE AND AFTER 23-00Z FOR THE I-95
TERMINALS. FOR THIS REASON, HAVE INCLUDED TEMPO GROUPS WHERE ANY
STORMS MAY CAUSE LOCALIZED AREAS OF VSBY/CIG RESTRICTIONS.
MODERATE-HIGH CONFIDENCE.
TONIGHT...VFR CONDITIONS TO START, BUT WILL FALL TO MVFR AND IFR
ESPECIALLY AFTER 04Z. SHOWERS AND THUNDERSTORMS LIKELY FOR THE
I-95 TERMINALS AND KMIV/KACY WHERE TEMPO GROUPS CONTINUE. STORMS
MAY CAUSE LOCALIZED AREAS OF VSBY/CIG RESTRICTIONS ALONG WITH
LOCALIZED HIGHER WINDS. AREAS OF MIST AND PATCHY FOG POSSIBLE. LOW
CONFIDENCE OVERALL, ESPECIALLY WITH REGARD TO TIMING.
THURSDAY...LINGERING IFR CONDITIONS SHOULD GRADUALLY IMPROVE TO
MVFR DURING THE MID-LATE MORNING HOURS. SHOULD FURTHER IMPROVE
TO VFR BY MID-LATE AFTERNOON. SHOWERS AND THUNDERSTORMS POSSIBLE
THROUGHOUT THE DAY. MODERATE-LOW CONFIDENCE.
OUTLOOK...
THURSDAY NIGHT THROUGH SUNDAY...OVERALL, VFR CONDITIONS.
HOWEVER, AFTERNOON AND EVENING SHRA/TSRA MAY RESULT IN BRIEF
SUB-VFR CONDITIONS IF A GIVEN STORM PASSES OVER A TERMINAL. SUB-
VFR CONDITIONS POSSIBLE AT NIGHT DUE TO FOG AND LOW CLOUDS, BUT
CONFIDENCE LOW ON TIMING AND PLACEMENT.
MARINE
NO MARINE HEADLINES ARE IN EFFECT THROUGH TONIGHT. ANOTHER
ROUND OF SHOWERS/STORMS EXPECTED LATE DAY TODAY INTO TONIGHT.
THESE COULD ONCE AGAIN BRING LOCALIZED WIND GUSTS IN EXCESS OF
34 KT.
OUTLOOK...
THURSDAY THROUGH SUNDAY...SUB-SCA CONDITIONS FOR THIS PERIOD.
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS POSSIBLE EACH
DAY. VSBY RESTRICTIONS POSSIBLE FROM TIME TO TIME, ESPECIALLY AT
NIGHT.
RIP CURRENTS...
FOR TODAY, A SOUTH/SOUTHWEST SHORE PARALLEL WIND OF AROUND
10-20 MPH AND BREAKING WAVES OF AROUND 2-3 FEET WILL RESULT IN A
MODERATE RISK FOR THE JERSEY SHORE. WITH WIND DIRECTION MAINLY
OFFSHORE ALONG THE DELAWARE BEACHES, A LOW RISK FOR RIP CURRENTS
IS IN PLACE. SIMILAR CONDITIONS ARE EXPECTED FOR THURSDAY SO
WE'LL CONTINUE WITH A MODERATE RISK FOR THE JERSEY SHORE AND A
LOW RISK OF RIP CURRENTS FOR THE DELAWARE BEACHES.
RIP CURRENTS OCCUR OFTEN IN THE VICINITIES OF JETTIES AND PIERS
AND THE SPEED OF THE CURRENTS ARE GENERALLY MAXIMIZED AT LOW
TIDES.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
HYDROLOGY
A FLOOD WATCH WAS ISSUED FOR AREAS ALONG AND SOUTH OF I-78 TODAY.
RAINFALL OF AROUND 0.5 INCHES TO UPWARDS OF 3 TO 4 INCHES FELL
ACROSS THE WATCH AREA. THIS RESULTS IN A SATURATED SURFACE AND
LOW FFG VALUES WITHIN THE WATCH AREA. IT WILL NOT TAKE MUCH TO
CAUSE FURTHER FLOODING ISSUES, ESPECIALLY IN SE PA, WHERE
WIDESPREAD FLOODING WAS REPORTED ON TUESDAY. RAINFALL RATES OF
2 TO 3 INCHES PER HOUR ARE POSSIBLE WITH THUNDERSTORMS ROLLING
THROUGH TONIGHT.
PHI WATCHES/WARNINGS/ADVISORIES
PA...FLOOD WATCH FROM 5 PM EDT THIS AFTERNOON THROUGH LATE TONIGHT
FOR PAZ060>062-070-071-101>106.
NJ...FLOOD WATCH FROM 5 PM EDT THIS AFTERNOON THROUGH LATE TONIGHT
FOR NJZ009-010-012>027.
DE...FLOOD WATCH FROM 5 PM EDT THIS AFTERNOON THROUGH LATE TONIGHT
FOR DEZ001>004.
MD...FLOOD WATCH FROM 5 PM EDT THIS AFTERNOON THROUGH LATE TONIGHT
FOR MDZ012-015-019-020.
MARINE...NONE.
SYNOPSIS...FITZSIMMONS/MPS
NEAR TERM...DESILVA/FITZSIMMONS/HOEFLICH/STAARMANN
SHORT TERM...FITZSIMMONS/MPS
LONG TERM...FITZSIMMONS/MPS
AVIATION...DESILVA/FITZSIMMONS/MPS
MARINE...DESILVA/FITZSIMMONS/MPS
HYDROLOGY...PHI
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