362
FXUS61 KPHI 131837
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
237 PM EDT SAT SEP 13 2025
SYNOPSIS
HIGH PRESSURE OVER THE AREA SLIDES OFFSHORE TONIGHT. A WEAKENING
COLD FRONT PASSES ACROSS THE REGION SUNDAY NIGHT. HIGH PRESSURE
THEN BUILDS OVER THE NORTHEAST FOR THE FIRST HALF OF THE NEW WEEK
BEFORE DEPARTING. LOW PRESSURE LIFTS ALONG THE COAST FOR THE MIDDLE
OF NEXT WEEK. HIGH PRESSURE BRIEFLY RETURNS TO CLOSE OUT THE WORK
WEEK. A COLD FRONT MAY IMPACT THE AREA NEXT WEEKEND.
NEAR TERM /THROUGH SUNDAY/
THRU SUNSET, FAIR WEATHER REMAIN ACROSS THE AREA BY-IN-LARGE. A
COUPLE LIGHT SHOWERS HAVE DEVELOP ACROSS NORTHERN NJ AND ACROSS THE
COASTAL AREAS OF NJ/DE (SOUTH OF ATLANTIC CITY). THESE SHOWERS WILL
NOT LAST LONG OR BE OF MUCH CONSEQUENCE WITH THE LIMITED INSTABILITY
AND RATHER PRONOUNCED INVERSION AROUND 700 MB. TEMPS WILL REMAIN A
BIT MILD FOR EARLY SEPTEMBER WITH WIDESPREAD LOW 80S FOR THE AREA.
WINDS WILL CONTINUE SOUTHWEST (MOSTLY) AT AROUND 10 MPH. WINDS WILL
BE MORE ONSHORE ACROSS EASTERN NJ AND SOUTHERN DELAWARE.
TONIGHT, FAIR WEATHER IS EXPECTED WITH HIGH PRESSURE OVERHEAD. UNDER
MOSTLY CLEAR SKIES, TEMPERATURES WILL DROP INTO THE UPPER 50S TO LOW
60S FOR THE REGION. PATCHY RURAL FOR MAY DEVELOP LATE, SO WE HAVE
INCLUDED THAT IN THE GRIDS ATTM. LIGHT WINDS OVERNIGHT.
ON SUNDAY, HIGH PRESSURE WILL REMAIN ACROSS THE AREA, SO THE FAIR
WEATHER WILL CONTINUE. THERE COULD BE SOME PATCHY MORNING FOG ACROSS
THE RURAL AREAS LIKE ON SATURDAY MORNING. AFTER THAT, THERE WILL BE
MOSTLY SUNNY SKIES EARLY THEN SOME AFTERNOON CLOUDS. HIGH TEMPS ON
SUNDAY WILL BE MILDER THAN TODAY WITH LOW/MID 80S COMMON ACROSS THE
AREA. HUMIDITY LEVELS WILL REMAIN IN CHECK HOWEVER WITH DEW POINTS
IN THE LOW 60S.
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
DECAYING COLD FRONT WASHES OUT OVER THE AREA SUNDAY NIGHT. MODELS
STILL FAIRLY DRY, AND NBM DOES NOT HAVE MEASURABLE POPS OVER THE
AREA. A SPOTTY SHOWER IN THE EVENING CANNOT BE RULED OUT, BUT QPF
WOULD BE MINIMAL, DESPITE ABUNDANT LOW LEVEL MOISTURE OVER THE AREA
GIVEN 60+ DEGREE DEW POINTS. PATCHY FOG SHOULD FORM DURING THE NIGHT
HOURS. LOWS WILL BE IN THE UPPER 50S TO LOW 60S.
SINCE THAT FRONT WILL BE WASHED OUT, THERE IS NEITHER COLD AIR
ADVECTION NOR DRY AIR ADVECTION FOR THE AREA MONDAY. CONDITIONS
REMAIN WARM AND MUGGY WITH HIGHS IN THE LOWER 80S, THOUGH COOLER AT
THE COASTS DUE TO ONSHORE FLOW, AND SURFACE DEW POINTS WILL BE IN
THE LOW 60S.
WARM AND MUGGY MONDAY NIGHT WITH PATCHY FOG ONCE AGAIN.
ON TUESDAY, COASTAL LOW PRESSURE OVER THE SOUTHEAST LIFTS TOWARDS
THE MID-ATLANTIC. CLOUDS INCREASE OVER THE AREA, AND TEMPERATURES
WILL BE A FEW DEGREES COOLER, GENERALLY TOPPING OFF IN THE MID 70S
ALONG THE COASTS TO OTHERWISE IN THE UPPER 70S TO AROUND 80. SOME
SPOTTY SHOWERS MAY MOVE INTO SOUTHERN DELMARVA AND POSSIBLY
EXTREME
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
THE AREA WILL FIND ITSELF BETWEEN BLOCKING HIGH PRESSURE TO THE
NORTHEAST AND A COASTAL LOW PASSING TO THE SOUTHEAST FOR THE MID-
WEEK PERIOD. MODELS ARE TRENDING CLOSER TO THE COAST, AS BOTH THE
12Z/13 GFS AND 12Z/CMC HAVE THAT LOW FAIRLY CLOSE TO THE DELMARVA
PENINSULA. THIS WOULD SPREAD PRECIPITATION FARTHER BACK INLAND. MAIN
TIMEFRAME WOULD BE TUESDAY NIGHT THROUGH THURSDAY NIGHT, AS THE
BLOCKING HIGH TO THE NORTHEAST WOULD KEEP THE LOW FROM MAKING MUCH
HEADWAY.
FOR NOW, WILL FOLLOW NBM POPS, AND GENERALLY CARRY A PROLONGED
PERIOD OF CHANCE POPS, MOSTLY 30 TO 50 PERCENT FOR ALL BUT THE
SOUTHERN POCONOS AND LEHIGH VALLEY, WHICH WILL MOSTLY BE SLIGHT
CHANCE.
WHILE QPF WILL MOSTLY BE LIGHT, THERE ARE SOME HINTS THAT BANDING OF
SHOWERS COULD RESULT IN LOCALLY HIGHER AMOUNTS. 12Z GFS HAS SOME
STRONG SHORTWAVE ENERGY ASSOCIATED WITH THE CLOSED UPPER LOW. THERE
ARE STILL DISCREPANCIES AMONG THE MODELS, SO IT WILL TAKE A COUPLE
OF DAYS TO GET A HANDLE ON THIS SYSTEM. REGARDLESS, THE AREA COULD
USE THE RAIN IF THE MORE AGGRESSIVE GFS PANS OUT.
LATEST NBM HAS HIGHS IN THE UPPER 70S TO AROUND 80 FOR WEDNESDAY AND
THURSDAY, BUT IF THIS LOW HOVERS OVER THE AREA, THEN THE CLOUDS AND
RAIN ASSOCIATED WITH THIS SYSTEM WOULD RESULT IN COOLER
TEMPERATURES, POSSIBLY IN THE LOW TO MID 70S.
LOW PRESSURE DEPARTS THURSDAY NIGHT AND THEN WEAK HIGH PRESSURE
BUILDS THROUGH THE REGION TO CLOSE OUT THE WORK WEEK. TEMPERATURES
SHOULD REBOUND BACK INTO THE UPPER 70S TO LOW 80S. CONTINUED MUGGY
WITH DEW POINTS IN THE 60S, POSSIBLY EVEN APPROACHING 70.
A COLD FRONT APPROACHES FOR SATURDAY.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THRU 00Z SUN
VFR. A COUPLE LIGHT SHOWERS POSSIBLE FOR FAR NORTH
NJ OR ALONG THE SHORE AREAS OF SOUTHERN NJ/DE. SOUTHWEST WINDS AROUND
10 KNOTS. HIGH CONFID.
TONIGHT
VFR EXPECTED WITH MOSTLY JUST HIGH CLOUDS. IT'S POSSIBLE
THAT SOME RURAL FOG MAY DEVELOP TOWARDS DAWN, BUT CONFID IN IT
OCCURRING IS LOW, SO NOT PUT IN TAFS ATTM. LIGHT VARIABLE WINDS.
MEDIUM/HIGH CONFID.
SUNDAY
VFR. LIGHT VARIABLE WINDS. HIGH CONFID.
OUTLOOK...
SUNDAY NIGHT THROUGH TUESDAY...SUB-VFR POSSIBLE IN FOG/STRATUS AT
NIGHT. VFR DURING THE DAY.
TUESDAY NIGHT THROUGH THURSDAY...POTENTIAL FOR SUB-VFR CONDITIONS
FROM TIME TO TIME IN SHRA. SUB-VFR CONDITIONS AT NIGHT IN
FOG/STRATUS.
MARINE
IT'S POSSIBLE THAT A FEW LIGHT SHOWERS MAY AFFECT THE SOUTHERN NJ
AND DELAWARE WATERS INTO THE EARLY EVENING, BUT THEY WILL BE OF
LITTLE CONSEQUENCE. OVERALL, FAIR WEATHER WILL PREVAIL FOR THE WATERS
FOR TONIGHT AND SUNDAY. WINDS WILL BE RATHER GENTLE WITH S/SW WINDS
THRU THE PERIOD. SEAS WILL AVERAGE 2 TO 3 FT FOR THE OCEAN AND
1 TO 2 FT FOR DELAWARE BAY.
OUTLOOK...
SUNDAY NIGHT THROUGH TUESDAY...SUB-SCA CONDITIONS.
TUESDAY NIGHT THROUGH THURSDAY...SCA CONDITIONS POSSIBLE, MAINLY DUE
TO SEAS BUILDING TO 5 FEET WITH THE PASSAGE OF A COASTAL STORM.
VISIBILITY RESTRICTIONS IN SHOWERS POSSIBLE.
RIP CURRENTS...
REST OF TODAY, SOUTHEAST WINDS AROUND 10-15 MPH. BREAKING WAVES
OF 2-3 FEET WITH AN EASTERLY SWELL AROUND 7-8 SECONDS. AS A
RESULT, WILL CONTINUE WITH A MODERATE RISK FOR THE DEVELOPMENT
OF DANGEROUS RIP CURRENTS FOR ALL BEACHES.
FOR SUNDAY, WINDS BECOME MORE SOUTHERLY AROUND 10-15 MPH. BREAKING
WAVES AROUND 1-2 FEET WITH AN EASTERLY SWELL AROUND 7-8 SECONDS.
DUE TO WINDS BECOMING MORE SHORE PARALLEL AND BREAKING WAVE
HEIGHTS SLIGHTLY LOWER, HAVE OPTED TO DOWNGRADE ALL BEACHES TO
A LOW RISK FOR RIP CURRENTS.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...SILVA
NEAR TERM...OHARA
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...MPS/OHARA
MARINE...MPS/OHARA
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