390
FXUS61 KPHI 082325
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
725 PM EDT TUE JUL 8 2025
SYNOPSIS
A SLOW MOVING FRONTAL BOUNDARY WILL PUSH SOUTHWARD INTO THE
AREA TONIGHT AND THEN 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 WEDNESDAY/
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR THE PORTIONS
OF THE AREA UNTIL 9 PM THIS EVENING. THE FLOOD WATCH REMAINS
UNCHANGED THROUGH 10 PM THIS EVENING AND THE HEAT ADVISORY
REMAINS UNCHANGED THROUGH 8 PM THIS EVENING.
THE UNSETTLED, ACTIVE, AND TROPICAL WEATHER PATTERN WILL CONTINUE
THROUGH WEDNESDAY DUE TO A SLOW-MOVING FRONT WHICH WILL WORK ITS WAY
TOWARD THE AREA BUT WON'T CROSS FULLY THROUGH THE AREA UNTIL FRIDAY.
THIS BOUNDARY IS ACTING AS THE MAIN TRIGGER FOR CONVECTION THIS
AFTERNOON IN BOTH THE SEVERE AND HYDRO DEPARTMENTS. LATEST RADAR AND
SATELLITE IMAGERY DEPICT A BROKEN LINE OF THUNDERSTORMS OVER CENTRAL
PENNSYLVANIA DOWN INTO MARYLAND AND NORTHERN VIRGINIA. AS THE
ATMOSPHERE CONTINUES TO DESTABILIZE THIS AFTERNOON, ANTICIPATION IS
FOR THIS LINE TO CONGEAL AND STRENGTHEN AS COLD POOL CONSOLIDATION
SHOULD OCCUR AS THE LINE OF STORMS TRACKS EAST INTO THE AREA. TIMING
OF STORMS LOOKS BE FROM NOW UNTIL 8-9 PM TONIGHT FROM WEST TO EAST.
THE PRIMARY THREAT WILL BE DAMAGING WIND GUSTS UP TO 70 MPH AS STEEP
LOW-LEVEL LAPSE RATES ARE PRESENT IN ADDITION TO MOISTURE LOADED
DOWNDRAFTS. FOR THIS REASON, SPC HAS MAINTAINED A SLIGHT RISK FOR
SEVERE WEATHER TODAY FOR OUR ENTIRE AREA. THERE ALSO REMAINS A HYDRO
THREAT AS PWATS REMAIN HIGH AND TALL, SKINNY CAPE PROFILES ARE
PRESENT IN SOUNDINGS. ANY STORM WILL BE CAPABLE OF PRODUCING
EFFICIENT RAINFALL RATES CAUSING LOCALLY HEAVY RAINFALL. THUS, WPC
HAS KEPT THE SLIGHT RISK FOR THE ENTIRE AREA THIS AFTERNOON AS WELL.
THE LINE OF STORMS WILL PUSH SOUTH AND EAST THROUGH THE URBAN
CORRIDOR AROUND RUSH HOUR AND TOWARDS/OFF THE COAST BY THE EVENING
HOURS. CONVECTION LARGELY SHOULD BE WINDING DOWN BY MIDNIGHT,
HOWEVER A FEW RESIDUAL SHOWERS MAY REMAIN AROUND THE AREA,
ESPECIALLY TOWARD THE COAST. SKIES TONIGHT WILL REMAIN MOSTLY
CLOUDY, KEEPING TEMPERATURES TO REMAIN VERY MILD OVERNIGHT IN THE
UPPER 60S TO MID 70S.
WEDNESDAY WILL VIRTUALLY BE A RINSE AND REPEAT KIND OF DAY IN TERMS
OF THE OVERALL FORECAST, EXCEPT THE FRONTAL BOUNDARY WILL HAVE MADE
ITS WAY CLOSER TO THE AREA, SUPPRESSING THE OVERALL THREAT OF
CONVECTION A BIT FURTHER SOUTH. EXPECTING PARTLY CLOUDY SKIES IN THE
MORNING TO GIVE WAY TO MOSTLY CLOUDY SKIES COME THE 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 MID-LATE AFTERNOON ON WEDNESDAY. GREATEST
THREAT WILL BE FROM PHILADELPHIA ON SOUTH, WHERE BETTER ATMOSPHERIC
PARAMETERS OVERLAP WITH ONE ANOTHER, SO SPC HAS INTRODUCED 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 AS LITTLE CHANGE IN THE OVERALL
ATMOSPHERIC ENVIRONMENT IS EXPECTED. HAVE CONSIDERED EXTENDING THE
CURRENT FLOOD WATCH THROUGH WEDNESDAY NIGHT, BUT DUE TO THERE BEING
A LARGE GAP IN BETWEEN POTENTIAL HEAVY RAIN PERIODS, WILL HAVE
FUTURE SHIFTS CONSIDER ANOTHER FLOOD WATCH TONIGHT. 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. LOOKS LIKE WE'LL FALL SHORT OF NEEDING ANY HEAT HEADLINES
THOUGH.
SHORT TERM /WEDNESDAY NIGHT 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. LINGERING SHOWERS AND THUNDERSTORMS
WEDNESDAY EVENING WILL BE CAPABLE OF LOCALLY HEAVY RAIN AND
FLASH FLOODING. WITH SB CAPE VALUES UP TO 1500 J/KG AND 30 TO 35
KT OF 0-6 KM BULK SHEAR, CANNOT RULE OUT DAMAGING WINDS FROM
THUNDERSTORMS.
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 CONTINUES ON FRIDAY.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
FAIRLY TYPICAL SUMMERTIME PATTERN ON TAP FOR THE LONG TERM
PERIOD WITH WARM AND HUMID CONDITIONS. SURFACE DEW POINTS WILL
GENERALLY BE IN THE MID 70S OR SO FROM FRIDAY NIGHT THROUGH
AROUND SUNDAY, AND THEN DEW POINTS LOOK TO COME DOWN A BIT FOR
THE START OF THE NEW WORK WEEK, GENERALLY IN THE UPPER 60S TO
LOW 70S. IT IS ALSO POSSIBLE THAT DURING THE PEAK HEATING OF THE
DAY THAT 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 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 /00Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR EXPECTED WITH MVFR CEILINGS POSSIBLE IN ANY
THUNDERSTORM ACTIVITY AND AGAIN POSSIBLY AFTER 06Z AS SOME
STRATUS DEVELOPS, HOWEVER CONFIDENCE IS LOW, AND GENERALLY HAVE
SCT CEILINGS BELOW 3000 FT TO COVER THIS POTENTIAL. SHOWERS AND
THUNDERSTORMS WILL WANE INTO THE EVENING HOURS AND TAPER OFF BY
MIDNIGHT. SOUTHWEST WINDS AROUND 3-5 KT. MODERATE-LOW CONFIDENCE.
WEDNESDAY...PRIMARILY VFR WITH ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS DEVELOPING BY MID-LATE AFTERNOON. ANY SHOWERS AND
STORMS MAY CAUSE LOCALIZED AREAS OF VSBY/CIG RESTRICTIONS.
SOUTHWEST WINDS AROUND 5-10 KT. MODERATE CONFIDENCE.
OUTLOOK...
WEDNESDAY 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 WEDNESDAY. SOUTH-SOUTHWEST
WINDS AROUND 10-20 KT THIS AFTERNOON, DIMINISH TO AROUND 5-10 KT
TONIGHT, BEFORE INCREASING AGAIN ON WEDNESDAY TO AROUND 10-15 KT.
SEAS OF 3-4 FEET. SHOWERS AND THUNDERSTORMS EXPECTED LATER THIS
AFTERNOON INTO THIS EVENING, WHERE LOCALIZED WIND GUSTS IN EXCESS OF
34 KT ARE POSSIBLE. ANOTHER ROUND OF THUNDERSTORMS EXPECTED ON
WEDNESDAY AFTERNOON.
OUTLOOK...
WEDNESDAY NIGHT 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, WINDS SHIFT SOUTHWESTERLY BECOMING MORE ALONGSHORE
FLOW AROUND 5-10 MPH IN THE MORNING INCREASING TO 10-15MPH IN
THE AFTERNOON. BREAKING WAVE HEIGHTS SHOULD BE IN THE 2-4 FOOT
RANGE DEPENDING ON BEACH ORIENTATION WITH A PRIMARY SE SWELL
INCREASING TO 4 FEET AT A 6-8 SECOND PERIOD. GIVEN THE TIDES
WILL BE AROUND LOW TIDE IN THE MORNING WITH THE INCREASE IN
SWELL, WILL MAINTAIN A HIGH RISK FOR RIP CURRENTS FOR THE
EASTERLY FACING BEACHES AND MODERATE ELSEWHERE.
FOR WEDNESDAY, SIMILAR CONDITIONS ARE EXPECTED EXCEPT WE WILL
CONFINE THE HIGH RISK OF RIP CURRENTS TO THE BEACHES IN ATLANTIC
AND CAPE MAY COUNTIES IN NJ WITH A MODERATE RISK ELSEWHERE.
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 FOR FLASH FLOODING REMAINS IN EFFECT UNTIL MIDNIGHT.
THIS IS A RESULT OF WIDESPREAD SHOWERS/STORMS EXPECTED TO OVERSPREAD
PORTIONS OF THE AREA CAPABLE OF PRODUCING RAINFALL RATES IN EXCESS
OF 2 INCHES PER HOUR. IF STORMS TRAIN OVER ANY ONE AREA FOR A PERIOD
OF TIME, THIS COULD RESULT IN LOCALIZED RAINFALL TOTALS OF 3+
INCHES. MAIN STEM RIVER FLOODING IS NOT ANTICIPATED BUT FLASH
FLOODING OF SMALLER STREAMS/CREEKS AND AREAS OF POOR DRAINAGE WILL
BE POSSIBLE. PLEASE HEED ANY ROAD CLOSURES AND LAW ENFORCEMENT
INSTRUCTIONS IN CASE OF FLOODING.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE EXPECTED ON WEDNESDAY
AFTERNOON AND EVENING. FURTHER FLOOD WATCHES ARE LIKELY TO BE NEEDED
AT A LATER TIME TO COVER THIS POTENTIAL.
PHI WATCHES/WARNINGS/ADVISORIES
PA...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ060>062-070-071-
101>106.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ070-071-
101>106.
NJ...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NJZ001-007>010-
012>027.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ008>010-
012>023-027.
HIGH RISK FOR RIP CURRENTS UNTIL 8 PM EDT THIS EVENING FOR
NJZ024>026.
DE...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR DEZ001>004.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR DEZ001>003.
MD...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MDZ012-015-019-020.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MDZ012-015-019-
020.
MARINE...NONE.
SYNOPSIS...MPS
NEAR TERM...DESILVA
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...DESILVA/MPS
MARINE...DESILVA/MPS
HYDROLOGY...PHI
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