596
FXUS61 KPHI 182036
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
436 PM EDT THU SEP 18 2025
SYNOPSIS
A WEAK AREA OF HIGH PRESSURE WILL REMAIN ACROSS THE MIDDLE
ATLANTIC REGION TONIGHT AND INTO FRIDAY. A COLD FRONT WILL PUSH
THROUGH THE REGION FRIDAY NIGHT. STRONG HIGH PRESSURE WILL BUILD
SOUTHEAST INTO THE REGION THROUGH THE WEEKEND. THE HIGH
PRESSURE WILL WEAKEN AND SHIFT SLOWLY EASTWARD THROUGH THE FIRST
HALF OF NEXT WEEK, WITH MODERATING TEMPERATURES AND A FEW
CHANCES FOR RAIN.
NEAR TERM /THROUGH FRIDAY/
SURFACE HIGH PRESSURE AND RIDGING ALOFT HAVE BROUGHT SUNNY
SKIES AND PLEASANT TEMPERATURES TO THE NORTHERN MIDDLE ATLANTIC
REGION THIS AFTERNOON. TEMPERATURES INLAND HAVE CLIMBED INTO THE
LOW/MID 80S WHILE 70S CONTINUE FOR DELMARVA AND SE NJ WHERE
CLOUDS PERSISTED LONGER EARLIER TODAY. WINDS HAVE BEEN RATHER
LIGHT FROM THE N & NW.
FOR TONIGHT, SKIES WILL REMAIN CLEAR WITH THE FAIR PATTERN
CONTINUING. WE'LL PROBABLY HAVE AREAS OF FOG ACROSS SOUTHERN NJ
AND DELMARVA IN AREAS THAT HAD MORE CLOUDS TODAY AND PLENTIFUL
RAINS YESTERDAY. FOG WILL BE MORE PATCHY IN OTHER AREAS. THE
DRIER AIR WILL CONTINUE TO ARRIVE FROM THE N/NW AND IT MAY NOT
FULLY MAKE IT INTO THE S/E AREAS BEFORE SUNSET. LOWS WILL BE IN
THE UPPER 50S TO LOW 60S MOST SPOTS. WINDS WILL BE LIGHT.
ANOTHER GOOD WEATHER DAY IS EXPECTED FRIDAY. PLENTY OF SUNSHINE
EARLY THE SOME CLOUDS FOR THE AFTERNOON. IT WILL BE VERY WARM
FOR THE END OF SEPTEMBER WITH HIGHS IN THE LOW/MID 80S ACROSS
THE REGION. AREAS NEAR THE SHORE AND THE SOUTHERN POCONOS WILL
HAVE HIGHS IN THE UPPER 70S. WINDS WILL BE LIGHT FAVORING THE
SOUTH OR SOUTHWEST.
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/
A COLD FRONT WILL PUSH SOUTH FRIDAY NIGHT AND CLEAR THE REGION
BY SATURDAY MORNING. NO PRECIPITATION IS EXPECTED WITH THIS
FRONTAL PASSAGE, BUT IT WILL BRING COOLER TEMPERATURES. LOWS ON
FRIDAY NIGHT ARE EXPECTED TO BE IN THE UPPER 40S ACROSS THE
HIGHER ELEVATIONS OF EASTERN PA AND FAR NORTHERN NJ, THE MID-
UPPER 50S ACROSS SOUTHEASTERN PA OUTSIDE OF THE URBAN CORRIDOR
AND NJ AWAY FROM THE COAST, AND NEAR 60 FOR COASTAL LOCATIONS,
THE URBAN CORRIDOR, AND THE DELMARVA.
WITH HIGH PRESSURE IN CONTROL ON SATURDAY, PARTLY CLOUDY SKIES
AND HIGHS IN THE MID 70S ARE EXPECTED. AS THE HIGH SLIDES SLOWLY
SOUTHEASTWARD SATURDAY NIGHT AND SUNDAY, THE AREA WILL BE
POSITIONED BETWEEN THE HIGH CENTER TO THE NORTHEAST AND A
STATIONARY BOUNDARY ACROSS PORTIONS OF THE MID-ATLANTIC. THIS
WILL SET THE STAGE FOR A PERIOD OF ONSHORE FLOW AND SOME
INCREASE IN CLOUD COVER FOR SATURDAY NIGHT AND SUNDAY. A
SPRINKLE OR TWO CANNOT BE RULED OUT ACROSS THE DELMARVA OR NEAR
THE SOUTHEASTERN COAST OF NJ, HOWEVER, THIS DOESN'T APPEAR TO
WARRANT TO INCLUSION OF POPS AT THIS TIME GIVEN THE AIRMASS IN
PLACE WILL BE FAIRLY DRY.
LOW TEMPERATURES SATURDAY NIGHT WILL LIKELY AGAIN BE IN THE
UPPER 40S ACROSS THE HIGHER ELEVATIONS OF EASTERN PA AND FAR
NORTHERN NJ, AND IN THE MID 50S TO LOWER 60S ELSEWHERE. HIGHS ON
SUNDAY ARE EXPECTED TO BE IN THE LOW-MID 70S AREAWIDE. LOWS
SUNDAY NIGHT WILL RANGE FROM THE LOW 50S ACROSS NORTHERN PARTS
OF THE AREA TO THE UPPER 50S ALONG THE COAST, IN THE URBAN
CORRIDOR, AND THE DELMARVA.
LONG TERM /MONDAY THROUGH THURSDAY/
WEAK UPPER-RIDGING WILL BE IN PLACE ACROSS THE AREA MONDAY INTO
MONDAY NIGHT, WITH SURFACE HIGH PRESSURE MAINTAINING STRONG
INFLUENCE. MOISTURE WILL BE ON THE INCREASE HOWEVER AS SOUTHERLY
FLOW RETURNS TO THE AREA. OVERALL, IT LOOKS TO BE A NICE DAY
WITH PARTLY SUNNY SKIES AND TEMPERATURES RISING INTO THE MID-
UPPER 70S AREAWIDE. TEMPERATURES OVERNIGHT SHOULD ALSO BE
WARMER, WITH UPPER 50S TO LOWER 60S BEING COMMON.
BEGINNING ON TUESDAY, THE UPPER-PATTERN WILL BECOME SLIGHTLY
MORE UNSETTLED. A SHORTWAVE AXIS SHOULD PASS TO THE NORTH OF THE
FORECAST AREA TUESDAY INTO TUESDAY NIGHT. WHILE THE BEST
FORCING SHOULD BE DISPLACED TO THE NORTH, THIS SYSTEM COULD BE
ENOUGH TO TRIGGER ISOLATED SHOWERS AND PERHAPS A STORM OR TWO.
THE HIGHEST CHANCE APPEARS TO BE TUESDAY AFTERNOON AND INTO THE
OVERNIGHT HOURS. AFTER THE PASSAGE OF THIS SHORTWAVE, THE
PATTERN LOOKS FAIRLY UNREMARKABLE, HOWEVER STILL UNSETTLED WITH
PERHAPS A WEAK IMPULSE OR TWO PASSING THROUGH WEDNESDAY INTO
THURSDAY. THEREFORE, SLIGHT CHANCE TO LOW-END CHANCE POPS APPEAR
WARRANTED (20-30%) BOTH DAYS. A MORE NOTABLE UPPER-TROUGH AND
ACCOMPANYING SURFACE LOW MAY BEGIN TO APPROACH THE AREA FROM THE
WEST LATE THURSDAY AND ESPECIALLY BEYOND.
TUESDAY AND WEDNESDAY LOOK FAIRLY SIMILAR IN TERMS OF
TEMPERATURES, WITH HIGHS IN THE LOW 80S AND LOWS IN THE LOW 60S.
THURSDAY CURRENTLY APPEARS TO BE SLIGHTLY COOLER WITH
INCREASING MOISTURE AND CLOUD COVER, WITH HIGHS GENERALLY IN THE
MID-UPPER 70S.
AVIATION /20Z THURSDAY THROUGH TUESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THRU SUNSET... DECREASING CLOUDS FOR SE NJ AND DELMARVA. VFR
EXPECTED. LIGHT NW TO W WINDS.
TONIGHT... VFR CONDITIONS WITH MAINLY CLEAR SKIES EXPECTED.
WE'LL LIKELY HAVE SOME RURAL FOG ACROSS DELMARVA AND SOUTH NJ
LATE TONIGHT SO WE'LL INCLUDE THAT IN KMIV/KACY TAF SITES. OTHER
SITES LESS CERTAIN WITH DRIER AIR ARRIVING THRU THE AFTERNOON.
OVERALL HIGH CONFID, BUT ONLY MODERATE CONFID IN FOG
OCCURRENCE/PLACEMENT.
FRIDAY... VFR EXPECTED AFTER ANY EARLY FOG. DAYTIME CU/SC WITH
SCT TO BKN 035-045 BASES. NORTHWEST WINDS AROUND 10 KNOTS BY
AFTERNOON. MEDIUM/HIGH CONFID.
OUTLOOK...
FRIDAY NIGHT THROUGH SATURDAY...VFR. NO SIGNIFICANT WEATHER.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...RESTRICTIONS ARE POSSIBLE
DEPENDING ON THE EXTENT OF POTENTIAL MARINE STRATUS.
MONDAY THOUGH MONDAY NIGHT...VFR. NO SIGNIFICANT WEATHER.
TUESDAY...PERIOD OF SUB-VFR CONDITIONS ARE POSSIBLE IN ISOLATED
SHOWERS AND STORMS, PARTICULARLY DURING THE AFTERNOON HOURS.
MARINE
FAIR WEATHER WILL CONTINUE ON THE WATERS TONIGHT AND FRIDAY. WEAK
HIGH PRESSURE THE REST OF TODAY AND TONIGHT WILL KEEP WINDS RATHER
LIGHT FAVORING A NW DIRECTION. A COLD FRONT WILL APPROACH FRIDAY AND
WHILE NO SIGNIFICANT WEATHER IS EXPECTED WITH IT, WINDS WILL SWITCH
BACK AROUND TO SOUTH AS IT APPROACHES. SEAS WILL BE MOSTLY AROUND 3
FT INTO TONIGHT THEN CLOSER TO 2 FT FRIDAY. 1 TO 2 FT WAVES FOR
DELAWARE BAY.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...NORTHERLY WINDS COULD APPROACH OR
EXCEED 25 KT FRIDAY NIGHT INTO SATURDAY BEHIND THE COLD FRONT. IN
ADDITION, SEAS WILL LIKELY BECOME ELEVATED, AT TIMES NEAR OR
EXCEEDING 5 FEET, SUNDAY THROUGH MONDAY. THEREFORE, AN SCA WILL
LIKELY BE NEEDED FOR AT LEAST PART OF THIS PERIOD.
MONDAY NIGHT THROUGH TUESDAY...CONDITIONS ARE EXPECTED TO BE BELOW
SCA CRITERIA WITH WINDS UNDER 25 KT AND SEAS UNDER 5 FEET.
RIP CURRENTS...
FOR FRIDAY, A MORE SOUTHERLY WIND NEAR 10 MPH IS FORECAST TO
DEVELOP WITH AN EAST-SOUTHEAST SWELL AROUND 8 SECONDS. BREAKING
WAVES IN THE SURF ZONE ARE FORECAST TO BE A LITTLE LOWER (AROUND
2 FEET) THAN THURSDAY, AND THEREFORE CONTINUED WITH A LOW RISK
FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS AT ALL BEACHES.
FOR SATURDAY, A SURGE IN NORTHEASTERLY WINDS ARE FORECAST TO
DEVELOP FROM NORTH TO SOUTH, WITH SPEEDS INCREASING TO 15-20
MPH. A SOUTHEAST SWELL IS FORECAST TO BE ON THE WEAKER SIDE
WITH WAVE HEIGHTS 1-2 FEET WITH A PERIOD OF 5-7 SECONDS.
BUILDING WAVES IN THE SURF ZONE (2-4 FEET) SHOULD BE MUCH MORE
DOMINANT OVER THE SWELL. AS A RESULT, WENT WITH A MODERATE RISK
FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS AT THE JERSEY
SHORE AND LOW AT THE DELAWARE BEACHES. IF THE STRONGER WIND SURGE
AND HIGHER BREAKING WAVES ARRIVE FASTER AT THE DELAWARE BEACHES,
THE RIP RISK WILL THEN INCREASE.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...COOPER/OHARA
NEAR TERM...FITZSIMMONS/OHARA
SHORT TERM...COOPER
LONG TERM...COOPER
AVIATION...COOPER/OHARA
MARINE...COOPER/GORSE/OHARA
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