563
FXUS61 KPHI 061805
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
205 PM EDT THU AUG 6 2026
WHAT HAS CHANGED
TIMING OF STORMS FRIDAY NIGHT HAS TRENDED SLIGHTLY LATER.
KEY MESSAGES
1. HOT AND VERY HUMID CONDITIONS ARE EXPECTED TO PERSIST
THROUGH TUESDAY OF NEXT WEEK. A HEAT ADVISORY IS IN EFFECT FOR
PORTIONS OF THE AREA.
2. THERE ARE DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
SATURDAY, AS WELL AS MUCH OF NEXT WEEK. THERE IS AT LEAST A
MARGINAL RISK EACH DAY FOR LOCALIZED HEAVY RAINFALL LEADING TO
FLASH FLOODING AND LOCALLY DAMAGING WIND GUSTS WITH ANY STRONGER
THUNDERSTORMS THAT DEVELOP.
DISCUSSION
KEY MESSAGE 1...HOT AND VERY HUMID CONDITIONS ARE EXPECTED TO
PERSIST THROUGH TUESDAY OF NEXT WEEK. A HEAT ADVISORY IS IN
EFFECT FOR PORTIONS OF THE AREA.
A RELATIVELY STAGNANT SYNOPTIC PATTERN IS DEVELOPING ACROSS OUR
REGION. QUASI ZONAL MID AND UPPER LEVEL FLOW WILL BE IN PLACE
THROUGH THE MIDDLE OF NEXT WEEK AS BERMUDA HIGH PRESSURE
PERSISTS OFFSHORE. THIS WILL KEEP A STEADY STREAM OF VERY WARM
AND MOIST AIR IN PLACE ACROSS THE REGION THROUGH THE PERIOD.
A PROLONGED PERIOD OF HOT AND, MOST NOTABLY, VERY HUMID
CONDITIONS IS EXPECTED TO REMAIN IN PLACE FOR THE NEXT SEVERAL
DAYS. WE LOOK TO HAVE A WEAK COLD FRONTAL PASSAGE EARLY SUNDAY,
USHERING IN SLIGHTLY DRIER AIR. THIS WILL GIVE SOME SLIGHT
REPRIEVE FROM THE EXCESSIVE HUMIDITY, THOUGH HIGHS WILL STILL
BE IN THE UPPER 80S TO LOW 90S. MOISTURE ADVECTION WILL RETURN
AGAIN BY MONDAY THOUGH, AND HOT AND VERY HUMID CONDITIONS ARE
ANTICIPATED TO RETURN MONDAY THROUGH TUESDAY. A SOMEWHAT
STRONGER COLD FRONT LOOKS TO COME THROUGH LATE TUESDAY OR
WEDNESDAY, WHICH WILL HELP BREAK THE EXCESSIVE HEAT AND HUMIDITY
SOME.
A HEAT ADVISORY REMAINS IN EFFECT FOR PORTIONS OF EASTERN
PENNSYLVANIA, MUCH OF NEW JERSEY EXCEPT THE FAR SOUTHERN
COUNTIES, AS WELL AS NEW CASTLE COUNTY, DELWARE.
KEY MESSAGE 2...THERE ARE DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS THROUGH SATURDAY, AS WELL AS MUCH OF NEXT WEEK.
THERE IS AT LEAST A MARGINAL RISK EACH DAY FOR LOCALIZED HEAVY
RAINFALL LEADING TO FLASH FLOODING AND LOCALLY DAMAGING WIND
GUSTS WITH ANY STRONGER THUNDERSTORMS THAT DEVELOP.
DIURNALLY DRIVEN INSTABILITY WILL MOSTLY BE IN THE 1000-2000
J/KG EACH AFTERNOON THROUGH THE NEXT SEVERAL DAYS ALONG WITH
PWATS IN THE 1.5-2" RANGE. MEAN FLOW WILL BE PREDOMINANTLY
SOUTHWESTERLY AND RELATIVELY WEAK THROUGH SATURDAY. THIS WILL
SUPPORT A CONTINUED LOCALIZED HEAVY RAINFALL THREAT WITH
POTENTIAL FOR FLASH FLOODING, ALTHOUGH WATER LOADED DOWNDRAFTS
COULD CAUSE LOCALIZED WIND DAMAGE. AREAS WITH VERY SATURATED
GROUND FROM RECENT RAINS WILL BE MOST PRONE TO EXPERIENCING
TREES FALLING.
FOR TODAY, THE MAIN LIMITING FACTOR IS THE LACK OF MID LEVEL
FORCING AND RELATIVELY WEAK LOW LEVEL CONVERGENCE. AS SUCH,
WHILE WE WILL CONTINUE TO SEE ISOLATED OR EVEN SCATTERED SHOWER
AND STORM DEVELOPMENT, NOT EXPECTING ANYTHING WIDESPREAD OR
PARTICULARLY LONG LIVED. THE MAIN THREATS WILL BE BRIEF HEAVY
DOWNPOURS AND GUSTY WINDS.
ON FRIDAY, A MID LEVEL SHORTWAVE TROUGH IS EXPECTED TO APPROACH
LATE IN THE DAY, PROVIDING MORE FORCING (AS COMPARED TO TODAY).
AS SUCH, STORM COVERAGE IS EXPECTED TO BE MORE WIDESPREAD, AND
STORMS SHOULD BE MORE ORGANIZED ALTHOUGH BULK SHEAR VALUES ARE
STILL RELATIVELY MODEST (UP TO 25 KT). ALL THAT BEING SAID,
CONTINUED CONCERN FOR HEAVY RAIN/FLASH FLOODING AND DAMAGING
WINDS. TO A LESSER EXTENT, THERE IS ALSO SOME RISK FOR HAIL,
GIVEN THE DEEP UNSTABLE LAYER.
DETAILS FOR SATURDAY'S CONVECTION REMAIN UNCLEAR, BUT WE COULD
CERTAINLY END UP WITH SOME POTENTIAL FOR FLASH FLOODING AND SEVERE
STORMS AGAIN. CURRENT INDICATIONS IN THE GUIDANCE SUPPORT A
LATER TIMING OF STORMS DURING THE EVENING OR EVEN OVERNIGHT
DEPENDING ON THE TIMING OF A WEAK COLD FRONT AND SHORTWAVE
TROUGH.
WE LOOK TO HAVE A WEAK COLD FRONTAL PASSAGE BY EARLY SUNDAY,
USHERING IN SLIGHTLY DRIER AIR. THIS COMBINED WITH SUBTLE
SUBSIDENCE ALOFT WILL HELP BRIEFLY LIMIT CONVECTION POTENTIAL ON
SUNDAY AND ALSO GIVE SOME SLIGHT REPRIEVE FROM THE EXCESSIVE
HUMIDITY, THOUGH HIGHS WILL STILL BE IN THE UPPER 80S TO LOW 90S.
MOISTURE AND FORCING ALOFT WILL RETURN BY MONDAY AS MEAN FLOW
SHIFTS MORE WESTERLY AND MID LEVEL FLOW INCREASES. THIS SHOULD
RESULT IN A GREATER SEVERE THUNDERSTORM THREAT COMPARED TO THIS
WEEK, AND PERHAPS SLIGHTLY LOWER FLASH FLOODING THREAT, BUT THE
DETAILS INTO THE PERIOD EARLY NEXT WEEK REMAIN UNCLEAR. LONG
STORY SHORT, MONDAY AND TUESDAY LOOK TO CONTINUE THE HOT AND
HUMID CONDITIONS AND DAILY THUNDERSTORM CHANCES.
A SOMEWHAT STRONGER COLD FRONT LOOKS TO COME THROUGH LATE
TUESDAY OR WEDNESDAY, WHICH WILL HELP BREAK THE EXCESSIVE HEAT
AND HUMIDITY SOME, BUT THE PATTERN ALOFT MAY STILL SUPPORT
DIURNALLY DRIVEN CONVECTION.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH TONIGHT...MAIN PERIOD FOR TSRA IMPACTS IS EXPECTED
THROUGH 02Z THIS EVENING. TSRA IS LIKELY TO BE CONFINED WEST OF
KMIV AND KACY, SO THOSE TAFS DON'T INCLUDE ANY MENTION OF TSRA
AT THIS TIME. OUTSIDE OF THE TSRA, EXPECT PREVAILING VFR THROUGH
06Z. AFTER 06Z, FOG DEVELOPMENT IS POSSIBLE. AT THIS POINT KRDG,
KTTN, AND KABE HAVE THE HIGHEST RISK FOR FOG. SOUTHWESTERLY
WINDS 5 TO 10 KT. MODERATE CONFIDENCE OVERALL, LOW CONFIDENCE ON
ANY FOG DEVELOPING.
FRIDAY...ONCE MORNING FOG DISSIPATES, PREVAILING VFR FOR MOST OF
THE DAY. TSRA MAY APPROACH THE REGION AS EARLY AS 18Z, BUT
IMPACTS AT TAF SITES ARE MORE LIKELY AFTER 21Z. SOUTHWESTERLY
WINDS UP TO 10 KT
OUTLOOK...
SATURDAY-SATURDAY NIGHT...MOSTLY VFR EXCEPT LOWER CONDITIONS
POSSIBLE WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS.
SUNDAY-SUNDAY NIGHT...VFR CONDITIONS EXPECTED.
MONDAY-TUESDAY...MOSTLY VFR EXCEPT LOWER CONDITIONS POSSIBLE WITH
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS.
MARINE
WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
THROUGH FRIDAY.
OUTLOOK...
FRIDAY NIGHT...GUSTY AND ERRATIC WINDS ARE POSSIBLE IN THE
VICINITY OF ANY THUNDERSTORMS FRIDAY EVENING.
SATURDAY-TUESDAY...CONDITIONS EXPECTED TO REMAIN BELOW ADVISORY
LEVELS THROUGH TUESDAY OF NEXT WEEK.
RIP CURRENTS...
FOR TODAY, SOUTH TO SOUTHWEST WINDS WILL INCREASE TO 15 TO 20
MPH IN THE AFTERNOON WITH BREAKING WAVES IN THE SURF ZONE OF 1
TO 3 FEET. THERE WILL BE A LIGHT EASTERLY SWELL WITH A PERIOD
AROUND 10 SECONDS. OPTED TO GO WITH A MODERATE RISK FOR THE
DEVELOPMENT OF DANGEROUS AND LIFE THREATENING RIP CURRENTS FOR
CAPE MAY AND ATLANTIC COUNTIES, WHERE THE WIND WILL HAVE A
GREATER ONSHORE COMPONENT, AND A LOW RISK ELSEWHERE FOR THE
JERSEY SHORE AND FOR DELAWARE BEACHES.
CONDITIONS WILL BE FAIRLY SIMILAR ON FRIDAY, THUS MAINTAINED THE
SAME RISK LEVELS AS TODAY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...HEAT ADVISORY UNTIL 8 PM EDT SATURDAY FOR PAZ070-071-102-104-
106.
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR PAZ060>062-101-103-105.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ054-055.
NJ...HEAT ADVISORY UNTIL 8 PM EDT SATURDAY FOR NJZ010-012>015-
017>020-027.
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR NJZ001-007>009.
DE...HEAT ADVISORY UNTIL 8 PM EDT SATURDAY FOR DEZ001.
MD...NONE.
MARINE...NONE.
DISCUSSION...JOHNSON/ROBERTSON/STAARMANN
AVIATION...JOHNSON/ROBERTSON
MARINE...JOHNSON/ROBERTSON
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