732
FXUS61 KPHI 130830
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
430 AM EDT SAT SEP 13 2025
SYNOPSIS
HIGH PRESSURE WILL BE IN CONTROL THROUGH TONIGHT. A DECAYING COLD
FRONT WILL APPROACH LATE SUNDAY. HIGH PRESSURE RETURNS ON MONDAY AND
TUESDAY. A COASTAL LOW MAY DEVELOP OFF THE SOUTHEAST US WHILE SLOWLY
DRIFTING NORTHEAST ON WEDNESDAY AND THURSDAY. HIGH PRESSURE ARRIVES
AGAIN ON FRIDAY.
NEAR TERM /THROUGH TONIGHT/
A RELATIVELY QUIET MORNING IS ONGOING, THOUGH SOME RADIATIONAL FOG
IS STARTING TO DEVELOP, MAINLY WITHIN THE HIGHER ELEVATIONS AND THE
COASTAL PLAIN. FOG WILL GRADUALLY EXPAND IN COVERAGE THROUGH THE
MORNING BUT MIX OUT NOT LONG AFTER DAYBREAK.
FOR TODAY, HIGH PRESSURE OVER THE MID-ATLANTIC IS IN CONTROL,
BRINGING A NICE DAY. HIGHS WILL GET INTO THE UPPER 70S/LOW 80S WITH
SOME DIURNAL CUMULUS DEVELOPMENT LEADING TO MOSTLY SUNNY TO PARTLY
CLOUDY SKIES. NOT MUCH ELSE OF NOTE, JUST A NICE MID-SEPTEMBER
SATURDAY.
FOR TONIGHT, RELATIVELY SIMILAR CONDITIONS EXPECTED, THOUGH A
SHORTWAVE SLIDING THROUGH WILL BRING SOME MORE UPPER LEVEL CLOUD
COVER. THIS SHOULD LIMIT FOG DEVELOPMENT, BUT AREAS THAT STAY MOSTLY
CLEAR OVERNIGHT (COASTAL PLAIN OF NJ AND DELMARVA) COULD SEE PATCHY
FOG DEVELOP YET AGAIN. OVERNIGHT LOWS DROP INTO THE UPPER 50S/LOW
60S.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
A LATE SUMMER WARM AND HUMID AIRMASS WILL BE IN PLACE DURING THE
SHORT TERM PERIOD. ALOFT, AN BLOCKING PATTERN WILL SET-UP THROUGH
MONDAY AS SURFACE HIGH PRESSURE LARGELY REMAINS IN CONTROL WITH THE
EXCEPTION OF A WEAK BOUNDARY PASSING THROUGH ON SUNDAY NIGHT.
MOSTLY SUNNY SKIES, SEASONABLY WARM TEMPERATURES AND MUGGY
CONDITIONS WILL BE ON THE TABLE FOR SUNDAY. HIGHS WILL REACH INTO
THE LOW TO MID 80S WITH DEW POINTS IN THE UPPER 50S TO LOW 60S.
WHILE THIS WON'T FEEL LIKE THE PEAK OF SUMMER HEAT, IT'LL DEFINITELY
BE MORE NOTICEABLE COMPARED TO THE WEATHER WE HAVE ENCOUNTERED OVER
THE PAST SEVERAL WEEKS. A COLD FRONT WILL APPROACH FROM THE
NORTHWEST LATE IN THE DAY, BUT WILL BE DECAYING AS IT NEARS OUR
AREA. SHOULDN'T OBSERVE ANYTHING IN TERMS OF PRECIPITATION AS MOST
FORECAST GUIDANCE LACKS ANY MOISTURE AND SKIES REMAIN MOSTLY CLEAR.
SO, OTHER THAN A WIND SHIFT ON SUNDAY NIGHT ASSOCIATED WITH THE
BOUNDARY, NOTHING OUT OF THE ORDINARY IS EXPECTED. LOWS WILL BE
SEASONABLE IN THE MID 50S TO LOW 60S.
FOR MONDAY, THERE WILL BE A LACK OF COLD AND DRY AIR BEHIND THE
FRONT WITH HIGH PRESSURE SETTING BACK UP OVER NEW ENGLAND. THIS WILL
RESULT IN THE RELATIVELY MUGGY AIRMASS TO LINGER INTO MONDAY AS
ONSHORE FLOW RECOMMENCES. HIGHS SHOULD BE PERHAPS A DEGREE OR TWO
LOWER THAN SUNDAY UNDER PARTLY CLOUDY SKIES. TRANQUIL WEATHER WILL
CONTINUE INTO MONDAY NIGHT, OTHER THAN AN INCREASE IN CLOUDS WITH
LOWS REMAINING NEAR SEASONABLE LEVELS.
LONG TERM /TUESDAY THROUGH FRIDAY/
THE BLOCKING PATTERN ALOFT WILL CONTINUE THROUGH MUCH OF THE LONG
TERM PERIOD AS UPPER LEVEL RIDGE WILL EXTEND ACROSS THE GREAT LAKES
REGION AS A CUT-OFF UPPER LEVEL LOW WILL MEANDER OVER THE SOUTHEAST
US / MID-ATLANTIC REGION THROUGH THURSDAY. AT THE SURFACE, HIGH
PRESSURE WILL LARGELY DOMINATE MUCH OF THE MID-ATLANTIC, WITH
POTENTIALLY A COASTAL LOW DEVELOPING OFF THE COAST OF NORTH CAROLINA
AROUND MID-WEEK.
WITH THE EXPECTED PATTERN SET-UP FOR MID-LATE WEEK, SHOULD SEE MORE
IN THE WAY OF CLOUDY WEATHER WITH THE CHANCE FOR SHOWERS RETURNING
TO MUCH OF THE AREA. ONSHORE FLOW SHOULD PERSIST FOR MUCH OF THE
WEEK AS SURFACE HIGH PRESSURE REMAINS TO OUR NORTH AND EAST. THE
GREATEST LIKELIHOOD OF PRECIPITATION WILL BE FURTHER SOUTH AND EAST,
ESPECIALLY OVER THE DELMARVA WHERE POPS UP TO 40-50% ARE POSSIBLE
THROUGH MID-WEEK. FURTHER NORTH AND WEST, POPS UP TO 20-30% ARE
POSSIBLE. THE PERIOD WITH THE HIGHEST THREAT FOR RAIN CHANCES APPEAR
TO BE WEDNESDAY NIGHT INTO THURSDAY AS THE POTENTIAL COASTAL LOW
MAKES ITS CLOSEST PASS TO THE AREA. ANY PRECIPITATION SHOULD REMAIN
RATHER LIGHT IN NATURE, SO NOT EXPECTING A WASHOUT BY ANY MEANS.
THIS SYSTEM SHOULD DEPART THE REGION BY THURSDAY NIGHT GIVING WAY TO
THE RETURN OF HIGH PRESSURE AND CLEARER WEATHER TO END THE WEEK.
IN TERMS OF TEMPERATURES FOR THE PERIOD, HIGHS WILL LIKELY REMAIN A
TOUCH BELOW NORMAL, WHEREAS LOWS WILL LIKELY BE A TOUCH ABOVE NORMAL
THANKS TO THE ABUNDANCE OF CLOUD COVER EXPECTED THROUGH THE PERIOD.
ALL IN ALL, CLOSE TO AVERAGE TEMPERATURES ARE EXPECTED.
AVIATION /09Z SATURDAY THROUGH WEDNESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...VFR THROUGH MOST OF THE NIGHT THOUGH PATCHY FOG
DEVELOPS OVER THE COASTAL PLAIN LATE, POTENTIALLY BRINGING
CONDITIONS DOWN AS LOW AS IFR TO KACY/KMIV. LOWER CHANCES FOR FOG AT
OTHER TERMINALS, DOWN AROUND 10-20% PROBABILITY, SO LEFT ANY FOG OUT
EVERYWHERE ELSE. LOW CONFIDENCE IN TIMING AND EXTENT IN ANY
RESTRICTIONS. WINDS LIGHT/VARIABLE.
TODAY...LOCALLY SUB-VFR CONDITIONS POSSIBLE EARLY MORNING DUE TO
SOME LOW CLOUDS/FOG, OTHERWISE VFR. ANY FOG MIXES OUT BY 12Z. WINDS
GENERALLY OUT OF THE SOUTHWEST AROUND 5-7 KT OR SO, GOING MORE
SOUTHERLY LATER IN THE DAY. MODERATE CONFIDENCE.
TONIGHT...PRIMARILY VFR. SOME PATCHY FOG BRINGING MVFR/IFR
RESTRICTIONS CANNOT BE RULED OUT, MAINLY FOR KACY/KMIV. WINDS
GENERALLY LIGHT LESS THAN 5 KT, FAVORING A SOUTHERLY DIRECTION. LOW
CONFIDENCE.
OUTLOOK...
SUNDAY THROUGH MONDAY NIGHT...VFR EXPECTED DURING THE DAY, WITH SUB-
VFR CONDITIONS WITH FG/BR POSSIBLE AT NIGHT.
TUESDAY THROUGH WEDNESDAY...PRIMARILY VFR EXPECTED WITH SUB-VFR
CONDITIONS POSSIBLE AT TIMES. A CHANCE FOR RAIN SHOWERS BEGINNING
TUESDAY NIGHT INTO WEDNESDAY.
MARINE
NO MARINE HEADLINES EXPECTED THROUGH TONIGHT. EAST/NORTHEAST WINDS
BECOME MORE SOUTHEASTERLY THIS AFTERNOON INTO TONIGHT, AROUND 10 KT
OR LESS. SEAS 2 TO 3 FEET.
OUTLOOK...
SUNDAY THROUGH TUESDAY...NO MARINE HEADLINES EXPECTED. FAIR WEATHER.
TUESDAY NIGHT THROUGH WEDNESDAY...SCA CONDITIONS POSSIBLE DUE TO
SEAS NEAR 5 FEET. RAIN SHOWERS POSSIBLE.
RIP CURRENTS...
FOR TODAY, NORTHEAST WINDS IN THE MORNING BECOME SOUTHEAST
WINDS AROUND 10-15 MPH IN THE AFTERNOON. BREAKING WAVES OF 2-3
FEET WITH AN EASTERLY SWELL AROUND 7-8 SECONDS. AS A RESULT,
HAVE MAINTAINED 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...DESILVA
NEAR TERM...HOEFLICH
SHORT TERM...DESILVA
LONG TERM...DESILVA
AVIATION...DESILVA/HOEFLICH
MARINE...DESILVA/HOEFLICH
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