643
FXUS61 KPHI 171825
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
ISSUED BY NATIONAL WEATHER SERVICE NEW YORK NY
225 PM EDT MON AUG 17 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES.
KEY MESSAGES
1. A COLD FRONT PASSES THROUGH THE REGION THIS EVENING.
2. ANOTHER COLD FRONT IS EXPECTED TO CROSS THROUGH THE REGION
WEDNESDAY NIGHT INTO THURSDAY RESULTING IN ADDITIONAL SHOWER
AND THUNDERSTORM CHANCES. LIKELY REMAINING UNSETTLED LATE
FRIDAY INTO THE FIRST HALF OF THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...A COLD FRONT WILL PASS THROUGH THE REGION THIS
EVENING. MOST SURFACE DEW POINTS WILL RESIDE IN THE THE LOWER HALF
OF THE 70S WITH ELEVATED PWAT VALUES. MLCAPE VALUES WILL INCREASE TO
1000 TO 1500, PERHAPS AS HIGH AS 2000 J/KG. THERE REMAINS THROUGH
THE EARLY EVENING THE POTENTIAL FOR SOME BRIEF LOCALLY HEAVY RAIN.
ALTHOUGH SHEAR WILL BE LIMITED AND ORGANIZED CONVECTION REMAINS NOT
LIKELY.
BEHIND THE COLD FRONT TEMPERATURES AND DEW POINTS WILL ONLY FALL
SLIGHTLY LATER TONIGHT. THERE MAY BE AREAS OF PATCHY FOG IN RURAL
LOCATIONS, ESPECIALLY WHERE ANY EARLY EVENING SHOWERS TAKE PLACE
THAT WOULD MOISTEN THE GROUND EVEN FURTHER. HIGH TEMPERATURES ON
TUESDAY WILL BE JUST ABOUT IDENTICAL TO MONDAY, BUT DEW POINTS WILL
DROP SOME WITH MAINLY LOWER AND MIDDLE 60S FURTHER NORTH, AND UPPER
60S TO AROUND 70 WELL SOUTH. WHILE WARM, IT SHOULD FEEL MORE
COMFORTABLE COMPARED TO MONDAY.
KEY MESSAGE 2...A COLD FRONT IS EXPECTED TO CROSS THROUGH THE
REGION WEDNESDAY NIGHT INTO THURSDAY RESULTING IN MORE SHOWER
AND THUNDERSTORM CHANCES.
IN THE WAKE OF TONIGHT'S COLD FRONT, WEAK HIGH PRESSURE WILL
BRIEFLY BUILD INTO THE REGION FOR TUESDAY AND MUCH OF WEDNESDAY.
AN UPPER-LOW WILL TRAVERSE PORTIONS OF ONTARIO AND QUEBEC
DURING THIS TIME, PASSING NORTH OF THE REGION WEDNESDAY NIGHT.
TO THE SOUTH OF THE UPPER-LOW, BROAD TROUGHING WILL BE IN PLACE
ACROSS MUCH OF THE NORTHEAST, WITH A FEW EMBEDDED SHORTWAVES
PIVOTING AROUND THE BASE OF THE TROUGH. AT THE SURFACE, A COLD
FRONT WILL BEGIN TO APPROACH THE AREA LATE WEDNESDAY, AND CROSS
THROUGH THE REGION LATE WEDNESDAY NIGHT INTO EARLY THURSDAY.
TIMING DISCREPANCIES REMAIN WITH THE FRONTAL PASSAGE AMONG THE
MODEL GUIDANCE. SOME GUIDANCE INDICATES THE FRONT PASSING THROUGH
THE REGION PRIMARILY DURING THE OVERNIGHT HOURS WEDNESDAY NIGHT AND
CLEARING THE REGION THURSDAY MORNING, WHILE THERE IS SOME
GUIDANCE SUGGESTING SLOWER TIMING. AT THIS POINT, TIMING
UNCERTAINTIES LIMIT CONFIDENCE IN WHETHER OR NOT THERE WILL BE ANY
NOTABLE SEVERE WEATHER OR FLASH FLOODING CONCERNS, BUT THIS WILL
CONTINUE TO BE MONITORED IN SUBSEQUENT FORECAST CYCLES. IF SLOWER
SOLUTIONS COME TO FRUITION THEN THE CHANCES OF IMPACTS FROM HEAVY
RAIN WOULD INCREASE. FOR NOW, POPS PEAK IN THE HIGH END CHANCE - LOW
END LIKELY RANGE FOR THE MAJORITY OF THE AREA THURSDAY.
LONGER RANGE NWP AND AI GUIDANCE SUGGESTS THAT THE PATTERN REMAINS
UNSETTLED LATER FRIDAY AND INTO THE WEEKEND AS THE FRONT COULD GET
HUNG UP JUST SOUTH OR EVEN OVER THE AREA WITH MULTIPLE AREAS OF
WEAK LOW PRESSURE RIDING ALONG AND MID-LEVEL TROUGHING REMAINING IN
PLACE. POPS CURRENTLY ARE MAINLY IN THE CHANCE TO LIKELY RANGE EACH
DAY DUE TO THE PRESENT UNCERTAINTIES IN TIMING AND PLACEMENT OF
THESE FEATURES AND ANY PROGRESSION IN THE LONG WAVE PATTERN. AT THIS
TIME POPS FOR THIS PERIOD ARE RELATIVELY HIGHER FURTHER SOUTH AND
EAST.
IN TERMS OF TEMPS, TUESDAY AND WEDNESDAY LOOK TO BE FAIRLY WARM
WITH MODESTLY INCREASING HUMIDITY. HIGHS LOOK TO BE MAINLY IN THE
UPPER 80S TO AROUND 90. TEMPS CURRENTLY LOOK A BIT COOLER IN
THE WAKE OF THE FRONT, WITH HIGHS IN THE LOW TO MID 80S AND LOWS
IN THE UPPER 50S TO MID 60S LATE THIS WEEK AND INTO THE
WEEKEND. PART OF THE REASON FOR THIS WILL BE DUE TO MORE IN TERMS
OF CLOUD COVER.
AVIATION /18Z MONDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY... A ROUND OF SHRA, PERHAPS A TSRA, MAY PASS ACROSS THE
TERMINALS IN THE LATE AFTERNOON/EARLY EVENING WITH BRIEF SUB-VFR
CONDS. WILL INCLUDE PROB30 GROUPS TO HANDLE THIS POTENTIAL. NW
WINDS 5 TO 10 KT. MODERATE CONFIDENCE.
TONIGHT...LINGERING SHRA POSSIBLE THROUGH 06Z OR SO. GENERALLY
VFR OUTSIDE OF ANY SHRA. N-NW WINDS 5 TO 10 KT. MODERATE
CONFIDENCE.
OUTLOOK...
TUESDAY THROUGH WEDNESDAY...VFR. NO SIG WX EXPECTED.
WEDNESDAY NIGHT THROUGH FRIDAY...PERIODS OF SCATTERED SHOWERS
AND PERHAPS STORMS ARE LIKELY, WITH THE GREATEST CHANCE
CURRENTLY APPEARING TO BE LATE WEDNESDAY NIGHT INTO THURSDAY.
SUB-VFR CONDITIONS ARE POSSIBLE WITH ANY SHOWERS OR STORMS.
MARINE
A FEW SHOWERS AND THUNDERSTORMS POSSIBLE EARLY EVENING.
SEAS SUBSIDE TO 2 TO 4 FEET AS WELL. THUS, SUB-SCA CONDITIONS
EXPECTED TONIGHT.
OUTLOOK...
TUESDAY THROUGH FRIDAY...NO MARINE HEADLINES CURRENTLY
ANTICIPATED WITH WINDS UNDER 25 KTS AND SEAS UNDER 5 FEET.
SCATTERED SHOWERS AND PERHAPS STORMS COULD LEAD TO PERIODS OF
VISIBILITY RESTRICTIONS WED NIGHT THROUGH A PORTION OF THU.
ANOTHER ROUND OF RESTRICTED VISIBILITIES ARE INCREASINGLY
LIKELY LATE FRIDAY INTO SATURDAY.
RIP CURRENTS...
WEST WINDS AT 10 TO 15 MPH THIS AFTERNOON. BREAKING WAVES WILL
AVERAGE 1 TO 2 FEET. THERE WILL BE AN INCREASING SOUTHERLY SWELL
WITH A 5 TO 7 SECOND PERIOD. THIS RESULTS IN A LOW RISK FOR THE
DEVELOPMENT OF DANGEROUS AND LIFE THREATENING RIP CURRENTS FOR
THE JERSEY SHORE AND DELAWARE BEACHES.
FOR TUESDAY, NORTH-NORTHEAST WINDS 5 TO 10 MPH IN THE MORNING
WILL GRADUALLY TURN TO BE MORE SOUTHERLY AT 5 TO 10 MPH IN THE
AFTERNOON. BREAKING WAVES WILL AVERAGE 1 TO 2 FEET. THERE WILL
CONTINUE TO BE A SOUTHEASTERLY SWELL WITH A 6 TO 8 SECOND
PERIOD. THE RESULT OF THESE CONDITIONS IS A LOW RISK FOR THE
DEVELOPMENT OF DANGEROUS AND LIFE THREATENING RIP CURRENTS FOR
THE JERSEY SHORE AND DELAWARE BEACHES.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
DISCUSSION...
AVIATION...
MARINE...
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