088
FXUS61 KPHI 201831
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
231 PM EDT SAT JUN 20 2026
WHAT HAS CHANGED
THE SYSTEM FOR EARLY THIS COMING WEEK HAS TRENDED SLOWER MEANING
SHOWERS AND THUNDERSTORMS MAY LAST INTO TUESDAY.
AVIATION AND MARINE SECTIONS UPDATED.
KEY MESSAGES
1. MOSTLY TRANQUIL TONIGHT AND SUNDAY.
2. A SYSTEM MOVES IN MONDAY INTO MONDAY NIGHT BRINGING THE THREAT
FOR HEAVY RAINFALL WITH AN ASSOCIATED FLOODING RISK ALONG WITH AT
LEAST SOME THREAT FOR SEVERE WEATHER.
DISCUSSION
KEY MESSAGE 1...MOSTLY TRANQUIL TONIGHT AND SUNDAY.
HIGH PRESSURE WELL TO THE SOUTH/WEST ACROSS THE LOWER OHIO
VALLEY WILL CONTINUE TO WEAKEN TONIGHT AND SUNDAY. ITS ASSOCIATED
RIDGE WILL REMAIN ACROSS OUR AREA THRU THE PERIOD. IT WILL PROVIDE
MOSTLY DRY WEATHER AND COMFORTABLE TEMPERATURES TONIGHT AND SUNDAY.
THERE ARE A FEW WEAK SHORTWAVES IN THE WEST/NORTHWEST FLOW ALOFT
AND THESE MAY TRIGGER A FEW SHOWERS THIS EVENING AND AGAIN SUNDAY.
POPS ARE IN THE 10% TO 20% RANGE FOR THESE SHOWERS.
KEY MESSAGE 2...A SYSTEM MOVES IN MONDAY INTO MONDAY NIGHT BRINGING
THE THREAT FOR HEAVY RAINFALL WITH AN ASSOCIATED FLOODING RISK ALONG
WITH AT LEAST SOME THREAT FOR SEVERE WEATHER.
FORECAST GUIDANCE CONTINUES TO INDICATE AN UNSETTLED START TO THE
WEEK WITH LOW PRESSURE IMPACTING THE AREA BUT THERE REMAIN DIFFERENCES
IN THE DETAILS OF HOW ALL THIS WILL PLAY OUT. THE MAIN QUESTION CONTINUES
TO BE THE EXACT TRACK OF THE LOW, WHICH WILL HAVE NOTABLE CONSEQUENCE
ON SPECIFIC IMPACTS.
THE MAIN TAKEAWAY THOUGH IS THAT IS THAT MOST AREAS WILL SEE AT LEAST
SOME SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON INTO THE EVENING,
POTENTIALLY EVEN LASTING INTO THE OVERNIGHT. CONSENSUS GUIDANCE
SHOWS PWAT VALUES (1.75- 2.00") NEAR THE CLIMATOLOGICAL MAXIMA,
SETTING UP THE RISK FOR HEAVY RAINFALL. NBM PROBABILITIES FOR 1+
INCHES OF RAIN WITH THE SYSTEM ARE IN THE 60-80 PERCENT RANGE FOR
AREAS ALONG AND NORTH OF THE I-95 CORRIDOR AND GENERALLY IN THE
25 TO 50 PERCENT RANGE FARTHER SOUTH. FOR 2+ INCHES, THESE PROBABILITIES
ARE AS HIGH AS 30 TO 50 PERCENT OVER NE PA INTO NW NJ, GENERALLY
AROUND 10 TO 25 PERCENT NEAR THE I-95 CORRIDOR, AND LESS THAN
10 PERCENT FARTHER SOUTH. IT IS WORTH NOTING THOUGH THAT FORECAST
MODELS NOTORIOUSLY STRUGGLE WITH QPF, ESPECIALLY WHEN IT INVOLVES
CONVECTION. LOOKING AT THE DIFFERENT DETERMINISTIC MODELS, THERE
ARE INDICATIONS THAT SOME PARTS OF OUR AREA COULD SEE 2-3+ INCHES
OF RAIN BUT THE QUESTION IS NOT JUST IF THIS OCCURS BUT IF SO, WHERE.
IF THE LOW TRACK FARTHER NORTH, THIS WOULD TEND TO KEEP THE HEAVIEST
RAIN GENERALLY FAVORED FOR NE PA INTO NW NJ WITH MORE OF A SEVERE
WEATHER THREAT SOUTH OF THESE AREAS. HOWEVER A TRACK FARTHER SOUTH
NEAR DELMARVA / SE PA / SOUTHERN NJ COULD UNFORTUNATELY MEAN THAT
THE HEAVIEST RAIN WOULD BE TARGETED NEAR THE I-95 CORRIDOR. WE'RE
STILL IN A REGION-WIDE DROUGHT THOUGH SO THAT COULD MITIGATE THE
FLOOD THREAT SOME. AT THIS TIME THE WEATHER PREDICTION CENTER HAS
AREAS FROM THE I-95 CORRIDOR NORTHWARD IN A SLIGHT RISK FOR EXCESSIVE
RAINFALL MEANING SCATTERED INSTANCES OF FLASH FLOODING WILL BE POSSIBLE.
FARTHER SOUTH, THE RISK IS MARGINAL MEANING ANY FLASH FLOODING WILL
BE MORE ISOLATED/LOCALIZED IF IT OCCURS. THE STORM PREDICTION CENTER
HAS MAINTAINED DELMARVA AND EXTREME SOUTHERN NJ IN A MARGINAL RISK
FOR SEVERE WEATHER.
IN TERMS OF TIMING, THE TREND IS FOR THE SYSTEM TO BE A BIT SLOWER
MEANING SHOWERS/STORMS MAY NOT REALLY MOVE IN UNTIL THE AFTERNOON
BUT WOULD LINGER THROUGH THE EVENING AND POTENTIALLY OVERNIGHT AS
WELL. THE SEVERE WEATHER THREAT SHOULD BE DIMINISHING THROUGH THE
EVENING BUT THE FLOOD THREAD MAY LAST INTO THE OVERNIGHT.
TUESDAY NOW LOOKS LIKE IT COULD SEE SOME ADDITIONAL SHOWERS AND
STORMS, MORE SCATTERED IN NATURE, DUE TO THE SYSTEM'S SLOWER MOVEMENT
WITH A FINAL PIECE OF THE UPPER LEVEL TROUGH MOVING THROUGH. THIS
SHOULD BE FOCUSED NEAR AND S/E OF THE URBAN CORRIDOR WITH THE SEVERE
WEATHER AND FLASH FLOODING THREAT LOOKING LOW BY THIS TIME.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT... VFR EXPECTED. A BRIEF SHOWER IS POSSIBLE THIS EVENING
(MOST PROBABLE KRDG/KABE). WEST TO NORTHWEST WINDS 10 TO 15 KTS
WITH GUSTS AROUND 20 KTS THEN DECREASING AFTER 00Z/01Z. HIGH
CONFID.
SUNDAY... VFR EXPECTED. A SMALL CHANCE FOR A SHOWER DURING THE
AFTERNOON. WEST WINDS 5 TO 10 KNOTS MUCH OF THE TIME. HIGH
CONFID.
OUTLOOK...
SUNDAY NIGHT...VFR. NO SIGNIFICANT WEATHER.
MONDAY AND MONDAY NIGHT...SUB-VFR CONDITIONS WITH SHOWERS AND SOME
THUNDERSTORMS LIKELY MAINLY FOR THE AFTERNOON AND EVENING PERIODS.
TUESDAY...SCATTERED SHOWERS/STORMS COULD BRING BRIEF RESTRICTIONS TO
THE I-95 TAF SITES AND POINTS S/E OF THERE. VFR SHOULD PREVAIL
FARTHER NORTH.
WEDNESDAY...VFR. NO SIGNIFICANT WEATHER.
THURSDAY...CHANCES FOR SHOWER/STORMS RETURN (30 TO 50 PERCENT
CHANCES) AND THESE COULD BRING BRIEF RESTRICTIONS.
MARINE
THE SMALL CRAFT ADVISORY WAS TAKEN DOWN AS GUSTS HAVE DECREASED
BACK BELOW 25 KTS AT THE NORTHERN NJ MARINE ZONES. SEAS AT THE
ADJACENT BUOY 44025 REACHED 5 FT EARLIER BUT ARE BACK TO 4 FT
ATTM. MOSTLY FAIR WEATHER EXPECTED TONIGHT AND SUNDAY. A BRIEF
SHOWER POSSIBLE.
OUTLOOK...
SUNDAY NIGHT...NO MARINE HEADLINES EXPECTED.
MONDAY THROUGH MONDAY NIGHT...SCA CONDITIONS EXPECTED WITH SOUTHERLY
WIND GUSTS INCREASING TO AROUND 30 KT WITH SEAS 4 TO 7 FEET.
TUESDAY...SCA CONDITIONS COULD LINGER EARLY.
WEDNESDAY THROUGH THURSDAY...SUB SCA CONDITIONS.
RIP CURRENTS...
REST OF TODAY, WEST WINDS AROUND 10-15 MPH ARE EXPECTED. HOWEVER,
THE ONSHORE SWELLS BEGIN TO WEAKEN, DECREASING TO AROUND 2 TO 4
FEET AT AROUND A 7 SECOND PERIOD. BREAKING WAVES IN THE SURF ZONE
SHOULD BE AROUND 2 FEET OR LESS AS A RESULT. THEREFORE, A LOW RISK
FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS IS FORECAST FOR ALL
BEACHES ON SATURDAY.
FOR SUNDAY, WESTERLY WINDS DIMINISH TO AROUND 10 MPH. ONSHORE SWELLS
WILL REMAIN WEAK AROUND 1 TO 2 FEET WITH A 7 SECOND PERIOD. BREAKING
WAVES IN THE SURF ZONE WILL BE AROUND 1 FOOT OR LESS. THEREFORE, A
LOW RISK FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS IS FORECAST
FOR ALL BEACHES ON SUNDAY.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
DISCUSSION...FITZSIMMONS/OHARA
AVIATION...FITZSIMMONS/OHARA
MARINE...FITZSIMMONS/OHARA
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