815
FXUS61 KPHI 081806
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
206 PM EDT SAT AUG 8 2026
WHAT HAS CHANGED
SEVERE THUNDERSTORM WATCHES HAVE BEEN ISSUED FOR PORTIONS OF THE
REGION THROUGH THE AFTERNOON AND INTO THE EVENING.
KEY MESSAGES
1. HOT AND HUMID CONDITIONS ARE EXPECTED TO PERSIST THROUGH
TUESDAY OF NEXT WEEK, THOUGH AN IMPROVEMENT IN HUMIDITY IS
EXPECTED SUNDAY INTO MONDAY. A HEAT ADVISORY IS IN EFFECT FOR
PORTIONS OF THE AREA THROUGH TODAY.
2. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO
DEVELOP THIS AFTERNOON AND EVENING. SUNDAY STILL LOOKS TO BE
LARGELY DRY, THEN DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS
WILL RETURN MONDAY AND INTO THE MIDDLE OF NEXT WEEK. THERE IS A
RISK FOR STRONG TO SEVERE THUNDERSTORMS AS WELL AS A MARGINAL
RISK FOR LOCALIZED HEAVY RAINFALL LEADING TO FLASH FLOODING.
DISCUSSION
KEY MESSAGE 1...HOT AND HUMID CONDITIONS ARE EXPECTED TO
PERSIST THROUGH TUESDAY OF NEXT WEEK, THOUGH AN IMPROVEMENT IN
HUMIDITY IS EXPECTED SUNDAY INTO MONDAY. A HEAT ADVISORY IS IN
EFFECT FOR PORTIONS OF THE AREA THROUGH TODAY.
A RELATIVELY STAGNANT SYNOPTIC PATTERN WILL REMAIN IN PLACE
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 HUMID CONDITIONS WILL CONTINUE
FOR THE NEXT SEVERAL DAYS. WITH DEWPOINTS REMAINING IN THE LOW
TO MID 70S AND HIGHS IN THE UPPER 80S TO LOW 90S TODAY, HEAT
INDICES WILL AGAIN BE NEAR 100 DEGREES THIS AFTERNOON, MAINLY
ALONG AND SOUTHEAST OF THE I-95 CORRIDOR. A WEAK COLD FRONTAL
PASSAGE SUNDAY WILL HELP USHER IN SLIGHTLY DRIER AIR AND ALLOW
DEWPOINTS TO MIX OUT DURING THE AFTERNOON HOURS BOTH SUNDAY AND
MONDAY. THIS WILL GIVE SOME SLIGHT REPRIEVE FROM THE EXCESSIVE
HUMIDITY, THOUGH HIGHS WILL STILL BE IN THE UPPER 80S TO LOW OR
EVEN MID 90S. THE LOWER DEWPOINTS SUNDAY AND MONDAY WILL RESULT
IN MAXIMUM HEAT INDICES MAINLY IN THE MID TO UPPER 90S, THOUGH
COULD GET NEAR 100 DEGREES IN DELMARVA AND FAR SOUTHERN NEW
JERSEY. SINCE THE FORECAST IS DECIDEDLY BELOW HEAT ADVISORY
CRITERIA, WE'VE OPTED NOT TO EXTEND IT TO COVER ADDITIONAL DAYS
AT THIS TIME, THOUGH IT WILL STILL BE HOT AND HUMID.
A HEAT ADVISORY REMAINS IN EFFECT THROUGH 8 PM THIS EVENING FOR
PORTIONS OF SOUTHEASTERN PENNSYLVANIA, PORTIONS OF NEW JERSEY,
AND NORTHERN DELWARE.
MOISTURE ADVECTION WILL RETURN AGAIN BY TUESDAY AHEAD OF
ANOTHER COLD FRONT, AND SLIGHTLY MORE HUMID CONDITIONS SHOULD
RETURN FOR TUESDAY. A SOMEWHAT STRONGER COLD FRONT LOOKS TO COME
THROUGH LATE TUESDAY OR WEDNESDAY, WHICH WILL HELP BRING A
SLIGHT REDUCTION IN TEMPERATURES. HIGHS BY WEDNESDAY AND
THURSDAY ARE MOSTLY IN THE MID TO UPPER 80S, WHICH WILL BE
CLOSER TO AVERAGE FOR EARLY TO MID AUGUST.
KEY MESSAGE 2...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE
TO DEVELOP THIS AFTERNOON AND EVENING. SUNDAY STILL LOOKS TO BE
LARGELY DRY, THEN DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS
WILL RETURN MONDAY AND INTO THE MIDDLE OF NEXT WEEK. THERE IS A
RISK FOR STRONG TO SEVERE THUNDERSTORMS AS WELL AS A MARGINAL
RISK FOR LOCALIZED HEAVY RAINFALL LEADING TO FLASH FLOODING.
ISOLATED TO SCATTERED THUNDERSTORMS ARE DEVELOPING ACROSS THE
AREA THIS AFTERNOON AND ARE EXPECTED TO CONTINUE INTO THIS
EVENING. WITH THESE, THERE IS A THREAT FOR SEVERE THUNDERSTORMS,
AND A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR TWO PORTIONS
OF THE AREA. THE INITIAL AREA OF FOCUS IS NEAR AND SOUTH OF
I-195 AND THE PA TURNPIKE. THE SECOND AREA IS ACROSS
NORTHWESTERN NEW JERSEY. SYNOPTIC FORCING ISN'T AS STRONG AS
WHAT WE HAD FRIDAY, THOUGH THE REMNANT DYNAMICS FROM THE
CONVECTION UPSTREAM ARE GIVING US BETTER FORCING AT THE
MESOSCALE LEVEL. PWATS LOOK SLIGHTLY LOWER THAN TODAY, BUT
OVERALL THE THERMODYNAMICS APPEAR SIMILAR TO FRIDAY (2000-3000
J/KG CAPE). NOTABLY, MEAN FLOW IS MORE WESTERLY AND A BIT
STRONGER THAN FRIDAY, SO DEEP LAYER WIND SHEAR IS A LITTLE
STRONGER IN THE 25-30 KT RANGE. THIS WILL POSE MORE OF A LARGE
HAIL RISK COMPARED TO FRIDAY AS WELL, BUT DAMAGING WINDS WILL BE
THE MAIN THREAT WITH ANY STRONGER STORMS. LOCALLY HEAVY
RAINFALL LEADING TO FLASH FLOODING IS ALSO POSSIBLE, BUT
THINKING THE STRONGER FLOW ALOFT SHOULD KEEP STORMS MOVING
FASTER AND POSE SLIGHTLY LESS OF A FLASH FLOOD RISK.
SPC HAS ADDED A SLIGHT (LEVEL 2 OUT OF 5) RISK FOR SEVERE
THUNDERSTORMS FOR MOST OF OUR AREA. WE REMAIN IN A MARGINAL
(LEVEL 1 OUT OF 4) RISK FOR EXCESSIVE RAINFALL FROM WPC.
WE LOOK TO HAVE A WEAK COLD FRONTAL PASSAGE BY SUNDAY, USHERING
IN SLIGHTLY DRIER AIR. THIS COMBINED WITH SUBTLE SUBSIDENCE
ALOFT WILL HELP BRIEFLY LIMIT CONVECTION POTENTIAL ON SUNDAY,
THOUGH CANNOT COMPLETELY RULE OUT SOME ISOLATED SEA BREEZE
CONVECTION IN THE AFTERNOON.
BETTER SUPPORT FOR FORCING ALOFT WILL RETURN BY LATE MONDAY AS
MEAN FLOW SHIFTS MORE WESTERLY AND MID LEVEL FLOW INCREASES.
AT THIS POINT THOUGH, IT APPEARS THE GREATER THREAT OF STORMS
WILL BE TO OUR NORTHWEST ON MONDAY WHERE SPC HAS A MARGINAL RISK
HIGHLIGHTED. STILL COULD GET SOME ISOLATED STORMS, BUT MONDAY IS
TRENDING DRIER LOCALLY AS THE LINGERING LOWER DEWPOINTS SHOULD
LIMIT OUR INSTABILITY A BIT. BETTER MOISTURE AND INSTABILITY
RETURN BY TUESDAY THOUGH, ALONG WITH BETTER STORM CHANCES. WITH
THE STRONGER MID LEVEL FLOW ALOFT, SEVERE THUNDERSTORMS STILL
LOOK TO BE A GREATER THREAT COMPARED TO FLASH FLOODING, BUT
THESE DETAILS REMAIN UNCLEAR.
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 SATURDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...ISOLATED TO SCATTERED THUNDERSTORMS IN THE AFTERNOON
MAY CAUSE LOCALIZED RESTRICTIONS, HOWEVER CONFIDENCE ON WHERE
ANY OF THIS MAY DEVELOP IS LOW. CONTINUING TO INCLUDE PROB30
GROUPS FOR TSRA AT ALL TERMINALS AND UPDATING AS CONFIDENCE
INCREASES WITH APPROACHING CONVECTION. SOUTHWEST WINDS NEAR 10
KTS, WITH GUSTS UP TO 18 KTS. STRONG GUSTS UP TO 40-50 KTS
POSSIBLE WITH ANY THUNDERSTORMS. HIGH CONFIDENCE IN PREVAILING
VFR, LOW CONFIDENCE ON SHOWER AND STORM DETAILS.
TONIGHT...PREVAILING VFR, THOUGH SOME PATCHY FOG MAY DEVELOP.
SOME ISOLATED SHOWERS AND THUNDERSTORMS COULD LINGER THROUGH
06Z, BUT CONFIDENCE ON THIS IS TOO LOW TO INCLUDE A TAF MENTION
AT THIS TIME. SOUTHWEST WINDS NEAR 5 KTS OR LESS. MODERATE
CONFIDENCE.
OUTLOOK...
SUNDAY-SUNDAY NIGHT...VFR CONDITIONS EXPECTED.
MONDAY-WEDNESDAY...MOSTLY VFR EXCEPT RESTRICTIONS POSSIBLE WITH
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS.
MARINE
A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR ALL COASTAL WATERS
OUT TO 20 NM AS WELL AS THE DELAWARE BAY (EXCEPT FOR COASTAL
WATERS NORTH OF MANASQUAN INLET). WIND GUSTS POTENTIALLY UP TO
40-50 KTS ARE POSSIBLE WITH ANY STRONG TO SEVERE THUNDERSTORMS
AS WELL AS LIGHTNING AND BRIEFLY HIGHER SEAS. OUTSIDE OF ANY
STORMS, SOUTHWEST TO SOUTH WINDS AROUND 10-20 KT WITH SEAS OF
2-4 FEET ARE EXPECTED.
OUTLOOK...
SUNDAY THROUGH WEDNESDAY...NO PREVAILING MARINE HAZARDS
EXPECTED. ISOLATED STORMS COULD DEVELOP ALONG THE SEA BREEZE
SUNDAY, POTENTIALLY IMPACTING THE BACK BAYS OR NEARSHORE
WATERS. THUNDERSTORMS POSSIBLE TUESDAY AND WEDNESDAY NIGHTS.
RIP CURRENTS...
FOR TODAY...SOUTHWESTERLY WINDS CONTINUE AND SHOULD INCREASE
SOME TO 10-20 MPH. BREAKING WAVES IN THE SURF ZONE ARE FORECAST
TO INCREASE SOME, ESPECIALLY FOR MUCH OF THE JERSEY SHORE, AT 2
TO 3 FEET. GIVEN THE INCREASING SURF AND SOUTHERLY WINDS, WENT
WITH A MODERATE RISK FOR THE DEVELOPMENT OF DANGEROUS RIP
CURRENTS FOR MOST OF THE JERSEY SHORE. BREAKING WAVES SHOULD BE
A LITTLE LOWER AND WINDS WILL HAVE MORE OF AN OFFSHORE OR SHORE
PARALLEL COMPONENT FOR THE DELAWARE BEACHES AND COASTAL
MONMOUTH COUNTY, THEREFORE WENT WITH A LOW RISK FOR THE
DEVELOPMENT OF DANGEROUS RIP CURRENTS.
FOR SUNDAY...SIMILAR CONDITIONS SUNDAY AS TODAY. SOUTHWESTERLY
WINDS CONTINUE AROUND 10-15 MPH. BREAKING WAVES IN THE SURF
ZONE ARE FORECAST TO REMAIN 1 TO 3 FEET. MAINTAINED THE SAME
RISK OF RIP CURRENTS FOR ALL COASTAL AREAS.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ070-071-
101>106.
NJ...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ008>010-
012>015-017>020-027.
DE...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR DEZ001.
MD...NONE.
MARINE...NONE.
DISCUSSION...AKL/GUZZO/STAARMANN
AVIATION...AKL/STAARMANN
MARINE...AKL/GORSE/STAARMANN
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