086
FXUS61 KPHI 212344
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
744 PM EDT SUN JUN 21 2026
WHAT HAS CHANGED
UPDATED THE AVIATION SECTION FOR THE 00Z TAFS.
KEY MESSAGES
1. A SYSTEM MOVES IN MONDAY INTO MONDAY NIGHT BRINGING THE
THREAT OF BOTH HEAVY RAINFALL WITH AN ASSOCIATED FLASH FLOOD
THREAT ALONG WITH THE THREAT OF SEVERE WEATHER.
2. A HIGH RISK OF RIP CURRENTS ON MONDAY FOR COASTAL OCEAN,
ATLANTIC, AND CAPE MAY COUNTY.
3. ANOTHER COLD FRONT IS EXPECTED TO APPROACH THE REGION LATE
THIS WEEK, BRINGING ONE MORE CHANCE FOR SHOWERS AND STORMS.
DISCUSSION
KEY MESSAGE 1...A SYSTEM MOVES IN MONDAY INTO MONDAY NIGHT
BRINGING THE THREAT OF HEAVY RAINFALL WITH AN ASSOCIATED FLASH
FLOOD THREAT ALONG WITH THE THREAT OF SEVERE WEATHER.
FORECAST MODELS HAVE COME IN TO BETTER AGREEMENT REGARDING THE TRACK
OF LOW PRESSURE THAT WILL IMPACT THE REGION FOR TOMORROW INTO
TOMORROW NIGHT BRINGING BOTH SEVERE WEATHER AND FLASH FLOOD THREATS.
SURFACE LOW PRESSURE IS EXPECTED TO TRACK EASTWARD ACROSS SOUTHERN
PA MONDAY AFTERNOON BEFORE MOVING ACROSS THE HEART OF OUR CWA
TOMORROW NIGHT EN ROUTE TO SOUTHERN NEW ENGLAND. THIS WILL
OCCUR ON THE DOWNSTREAM SIDE OF A FAIRLY BROAD UPPER LEVEL
TROUGH AS EMBEDDED UPPER DISTURBANCES IN THE WSW FLOW ALOFT MOVE
THROUGH. UNFORTUNATELY THIS SET UP IN THE WARM SEASON IS QUITE
FAVORABLE FOR BOTH SEVERE WEATHER AND FLASH FLOODING AS IT WILL
BRING BOTH STRONG LOW LEVEL AND DEEP LAYER SHEAR WITH VEERING
WINDS PROFILES ALONG WITH PWATS MAXING OUT IN THE 1.8 TO 2.4
INCH RANGE, CLOSE TO CLIMATOLOGICAL MAXES. ML CAPE VALUES LOOK
TO MAX OUT AROUND 750 TO TO 1500 J/KG WHICH COMBINED WITH DEEP
LAYER SHEAR OF 40+ KNOTS AND 0-3 KM SHEAR OF 30-35+ KNOTS ALONG
WITH SUFFICIENT FORCING WILL BE ENOUGH FOR SEVERE WEATHER. AND
THE HIGH PWAT VALUES ALONG WITH THE POTENTIAL FOR THERE TO BE
MULTIPLE ROUNDS OF STORMS WITH SOME TRAINING HAS US CONCERNED
ABOUT FLASH FLOODING AS WELL.
GETTING INTO THE DETAILS, THE LOW WILL BE APPROACHING BY
TOMORROW AFTERNOON AS IT MOVES FROM OHIO INTO SOUTHERN PA.
AHEAD OF THE LOW, ITS WARM FRONT LOOKS TO LIFT NORTHWARD THROUGH
THE DAY AS IT MOVES FROM NEAR DELMARVA / SOUTHERN NEW JERSEY
EARLY IN THE DAY TOWARDS THE I-80 CORRIDOR BY LATE DAY. THERE
WILL LIKELY BE SOME INITIAL SHOWERS AND POSSIBLE STORMS AROUND
BY LATE MORNING INTO THE EARLY AFTERNOON OVER NE PA INTO OUR
NORTHERN NJ ZONES NEAR THE WARM FRONT BUT THE MORE SIGNIFICANT
CONVECTION IN TERMS OF SEVERE WEATHER AND FLOODING LOOKS TO HOLD
OFF UNTIL MAINLY AFTER 18Z. EXPECT THAT GETTING INTO THE MID
AFTERNOON AND BEYOND THAT WE'LL SEE CONVECTION
DEVELOPING/STRENGTHENING BOTH NEAR THE WARM FRONT IN OUR
AFORMENTIONED NORTHERN ZONES AS WELL AS NEAR AND AHEAD OF A
DEVELOPING LEE SURFACE TROUGH OVER WESTERN MD INTO SE PA AHEAD
OF THE LOW. SO TIMING WISE, THE WINDOW OF CONCERN FOR OUR
FORECAST AREA IS ROUGHLY 3-11 PM. THERE MAY BE SOME DISCRETE
CELLS INITIALLY BUT WITH TIME THE CONVECTIVE MODE SHOULD BECOME
MULTI-CELL CLUSTERS WITH THE POTENTIAL FOR EMBEDDED SUPERCELLS
AS STORMS MOVE THROUGH THE AREA DURING THE LATE AFTERNOON AND
EVENING PERIOD. DAMAGING WINDS WILL BE THE BIGGEST THREAT IN
TERMS OF SEVERE WEATHER BUT WITH THE STRONGLY VEERING LOW LEVEL
WINDS THERE WILL BE A TORNADO THREAT AS WELL. THE LATEST UPDATE
FROM THE STORM PREDICTION CENTER NOW HAS JUST ABOUT ALL OF OUR
AREA IN A SLIGHT RISK FOR SEVERE WEATHER, MEANING SCATTERED
SEVERE STORMS WILL BE POSSIBLE.
REGARDING THE FLASH FLOOD THREAT, CELL MOTION WILL BE FAIRLY FAST
BUT THERE WILL BE THE POTENTIAL FOR MULTIPLE ROUNDS OF STORMS
DURING THE LATE AFTERNOON / EVENING PERIOD ALONG WITH THE
POTENTIAL FOR STORMS TO TRAIN GETTING INTO THE EVENING PERIOD.
THE PWAT VALUES PROGGED TO BE NEAR OR ABOVE 2 INCHES INDICATE
THE POTENTIAL FOR 1-2+ INCH PER HOUR RAIN RATES IN CONVECTION.
FFG VALUES ARE NOT TERRIBLY LOW GIVEN HOW DRY IT'S BEEN BUT ARE
AS LOW AS 1 HR VALUES OF 1.5 TO 2.0 INCHES AND 3 HOUR VALUES OF
2.0 TO 3.0 INCHES IN THE URBAN CORRIDOR. AND GIVEN THE SETUP
JUST DESCRIBED THESE VALUES COULD BE REACHED OR EXCEEDED. THERE
WAS SOME CONSIDERATION REGARDING ISSUING A FLOOD WATCH FOR FLASH
FLOODING FOR OUR URBAN CORRIDOR ZONES BUT IN COLLABORATION WITH
SURROUNDING OFFICES WE ARE HOLDING OFF ON THIS FOR NOW.
AS MENTIONED, THE PEAK OF THE CONVECTION WITH ITS ASSOCIATED SEVERE
WEATHER AND FLASH FLOOD THREATS LOOKS TO BE THROUGH THE EVENING WITH
STORMS WEAKENING AND MOVING OUT THROUGH THE OVERNIGHT PERIOD AS THE
LOW AND ITS ASSOCIATED COLD FRONT MOVE EASTWARD TOWARDS THE COAST.
FOR TUESDAY, A SECONDARY COLD FRONT MOVING THROUGH ALONG WITH SOME
LINGERING INSTABILITY COULD RESULT IN SOME ADDITIONAL SCATTERED
SHOWERS/STORMS BY THE AFTERNOON. BUT THESE ARE NOT EXPECTED TO POSE
A SEVERE WEATHER OR FLOOD THREAT AND SHOULD BE CONFINED MAINLY TO
AREAS MAINLY NEAR AND S/E OF THE URBAN CORRIDOR.
KEY MESSAGE 2...A HIGH RISK OF RIP CURRENTS ON MONDAY FOR COASTAL
OCEAN, ATLANTIC, AND CAPE MAY COUNTY.
FOR MONDAY, SOUTH-SOUTHEASTERLY WINDS WILL INCREASE TO
AROUND 15-20 MPH WITH GUSTS UPWARDS OF 25-30 MPH. SOUTH-
SOUTHEASTERLY ONSHORE SWELLS WILL INCREASE TO AROUND 3 TO 4 FEET
WITH A 6 SECOND PERIOD. BREAKING WAVES IN THE SURF ZONE WILL
GENERALLY BE 2 TO 4 FEET. DUE TO THE INCREASE IN A MORE ONSHORE
WIND AND WAVE HEIGHTS ALSO INCREASING, A HIGH RISK FOR THE
DEVELOPMENT OF DANGEROUS RIP CURRENTS IS FORECAST FOR COASTAL
OCEAN, ATLANTIC, AND CAPE MAY COUNTY. A RIP CURRENT STATEMENT
HAS BEEN ISSUED FROM 8 AM TO 8 PM MONDAY FOR THESE COASTAL
AREAS. THERE IS A MODERATE RISK FOR THE DEVELOPMENT OF DANGEROUS
RIP CURRENTS AT COASTAL MONMOUTH AND THE DELAWARE BEACHES. FOR
THESE COASTAL ZONES, THE WIND IS MORE SHORE PARALLEL.
FOR TUESDAY, WINDS ARE OFFSHORE WITH A NORTH-NORTHWEST WIND AT
AROUND 10 MPH. SOUTH- SOUTHEASTERLY ONSHORE SWELLS WILL BE
AROUND 2 TO 3 FEET WITH A 5-6 SECOND PERIOD. BREAKING WAVES IN
THE SURF ZONE WILL GENERALLY BE 1 TO 2 FEET. DUE TO THESE
FORECAST CONDITIONS, THERE IS A LOW RISK FOR THE DEVELOPMENT OF
DANGEROUS RIP CURRENTS AT ALL THE NEW JERSEY AND DELAWARE
BEACHES.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
KEY MESSAGE 3...ANOTHER COLD FRONT IS EXPECTED TO APPROACH THE
REGION LATE THIS WEEK, BRINGING ONE MORE CHANCE FOR SHOWERS AND
STORMS.
ANOTHER COLD FRONT IS EXPECTED TO APPROACH OUR REGION LATE IN THE
WEEK (LIKELY CROSSING THROUGH OUR REGION FRIDAY INTO SATURDAY. AT
THIS POINT, THE MAJORITY OF GUIDANCE KEEPS THE MAIN LOW WELL NORTH
OF OUR REGION (GENERALLY CROSSING ACROSS SOUTHERN CANADA). THIS WILL
MEAN THAT THE AREA OF MOST SYNOPTIC SCALE FORCING WILL ALSO STAY
NORTH OF OUR REGION. HOWEVER, EVEN THE MODEST MESOSCALE FORCING
AHEAD OF AND WITH THE FRONT SHOULD BE ENOUGH FOR SOME SCATTERED
SHOWERS AND STORMS AS THE FRONT APPROACHES.
SOUTHWESTERLY FLOW AHEAD OF THE FRONT SHOULD ALLOW FOR PLENTY OF
MOISTURE ADVECTION AHEAD OF THE RAIN CHANCES. HOWEVER WITH THE
FORCING MORE CENTERED NORTH OF THE REGION, THAT COULD LIMIT HOW
WIDESPREAD SIGNIFICANT RAIN IS WITH THIS EVENT. AS FOR WHAT HAZARDS
TO EXPECT WITH THIS EVENT, THAT WILL BE HIGHLY DEPENDENT ON THE
TIMING OF THE SHOWERS AND STORMS, WHICH THE SPREAD IN MODEL GUIDANCE
IS AS MUCH AS 18 HOURS AT THIS POINT.
AVIATION /00Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. WEST-NORTHWEST TO WEST WINDS AROUND 10 KNOTS,
BECOMING LIGHT AND VARIABLE TO LOCALLY CALM. MODERATE CONFIDENCE.
MONDAY...VFR THROUGH MOST OF THE DAY WITH GRADUALLY LOWERING CEILINGS.
SHOWERS AND SOME THUNDERSTORMS MOSTLY IN THE AFTERNOON FROM WEST
TO EAST. THIS COULD BE MOSTLY IN THE FORM OF A LINE OF STRONG
TO SEVERE THUNDERSTORMS WITH LOCALLY STRONG WINDS. MVFR TO IFR
CONDITIONS WILL OCCUR WITH THE CONVECTION. AS OF NOW, INCLUDED A
PROB30 FOR THUNDERSTORMS. EAST TO SOUTHEASTERLY WINDS INCREASING
TO 8-12 KNOTS WITH SOME GUSTS TO AROUND 20 KNOTS. LOW CONFIDENCE
REGARDING THE TIMING DETAILS OF THE SHOWERS/THUNDERSTORMS.
OUTLOOK...
MONDAY NIGHT INTO TUESDAY...SHOWERS AND SOME THUNDERSTORMS WILL
RESULT IN MVFR TO IFR CONDITIONS. THE MOST WIDESPREAD COVERAGE
IS EXPECTED MONDAY NIGHT, WITH STORMS MOVING OUT FROM WEST TO
EAST AS EARLY AS 12Z.
WEDNESDAY...VFR. NO SIGNIFICANT WEATHER.
THURSDAY AND FRIDAY...CHANCES FOR SHOWER/STORMS RETURN (30 TO
50 PERCENT CHANCES) AND THESE COULD BRING BRIEF RESTRICTIONS.
MARINE
THE CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY
CRITERIA THROUGH TONIGHT.
SMALL CRAFT ADVISORY IN EFFECT MONDAY AND MONDAY NIGHT WITH
SOUTHERLY WIND GUSTS INCREASING TO 30 KNOTS WITH SEAS BUILDING
TO 4 TO 6 FEET. SOME GUSTY THUNDERSTORMS WILL BE POSSIBLE MONDAY
EVENING.
OUTLOOK...
TUESDAY THROUGH FRIDAY...SUB SCA CONDITIONS.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...HIGH RISK FOR RIP CURRENTS FROM MONDAY MORNING THROUGH MONDAY
EVENING FOR NJZ024>026.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 PM MONDAY TO MIDNIGHT EDT MONDAY
NIGHT FOR ANZ430-431.
SMALL CRAFT ADVISORY FROM NOON MONDAY TO 6 AM EDT TUESDAY FOR
ANZ450>455.
DISCUSSION...FITZSIMMONS/GUZZO/JOHNSON
AVIATION...GORSE/JOHNSON/RCM
MARINE...FITZSIMMONS/GUZZO/JOHNSON
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