422
FXUS61 KPHI 260727
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
327 AM EDT TUE AUG 26 2025
SYNOPSIS
HIGH PRESSURE CENTERED WELL TO OUR WEST TODAY WILL SLIDE EASTWARD
AND ACROSS THE MID-ATLANTIC ON WEDNESDAY, BEFORE SHIFTING OFFSHORE
ON THURSDAY. A COLD FRONT THEN CROSSES OUR AREA LATE THURSDAY NIGHT
AND DURING FRIDAY, FOLLOWED BY HIGH PRESSURE OVER THE WEEKEND INTO
EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
WEAK HIGH PRESSURE DOMINATES THE REGION PRESENTLY, KEEPING SKIES
MOSTLY CLEAR WITH LOW HUMIDITY. THIS SHOULD RESULT IN A PLEASANT
START TO THE DAY, ESPECIALLY FOR LATE AUGUST. TEMPERATURES WILL
WARM PLEASANTLY UNDER OUR MID-APRIL SUN ANGLE (YES, I SAID THAT
RIGHT). ONE MINOR FLY IN THE OINTMENT IS A VERY WEAK COLD FRONT
AND ACCOMPANYING DISTURBANCE ALOFT WHICH WILL MOVE INTO THE
REGION LATER TODAY AND CROSS THIS EVENING. CAMS GUIDANCE WANTS
TO GENERATE A FEW SPOTTY SHOWERS WITH IT, SO CAN'T COMPLETELY
RULE THEM OUT, ESPECIALLY NORTH AND WEST OF I-95, BUT CONFIDENCE
IS LOW. OTHERWISE, THERE WILL BE A BIT MORE CLOUD BUILD-UP THIS
AFTERNOON, WITH HIGHS IN THE 70S TO NEAR 80. THESE READINGS WILL
BE SEVERAL DEGREES BELOW NORMAL FOR LATE AUGUST, WHEN MOST AREAS
SHOULD BE IN THE LOW-MID 80S STILL.
TONIGHT, CLOUDS WILL FADE OUT AS THE WEAK FRONT MOVES THROUGH
AND INSOLATION DIMINISHES, THOUGH UPPER TROUGHING WILL ACTUALLY
BE INCREASING. ANY SPOTTY SHOWERS MAINLY N AND W SHOULD
DISSIPATE, WITH LOWS ENDING UP IN THE HIGH 40S POCONOS, 50S MOST
EVERYWHERE ELSE, EXCEPT NEAR 60 IN THE URBAN CENTERS AND NEAR
TIDAL WATERS. AS WITH THE DAYTIME HIGHS, THESE WILL BE SEVERAL
DEGREES BELOW NORMAL, WITH MOST REGIONAL NORMALS CURRENTLY IN
THE LOW-MID 60S FOR LOWS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
AS THE AXIS OF AN UPPER-LEVEL TROUGH CROSSES THE NORTHEAST AND MID-
ATLANTIC, PLENTY OF SHORTWAVE ENERGY IS FORECAST TO ACCOMPANY IT.
SURFACE HIGH PRESSURE BUILDING EASTWARD FROM THE OHIO VALLEY WILL
PLACE A TIGHTENED PRESSURE GRADIENT ACROSS OUR REGION. GIVEN COLDER
AIR ALOFT ASSOCIATED WITH THE TROUGH ALOFT, DAYTIME CUMULUS SHOULD
DEVELOP AND THERE SHOULD BE A NORTHWEST TO WEST-NORTHWEST BREEZE.
DESPITE THE AIR MASS BEING RATHER DRIER AS DEW POINTS DROP INTO THE
40S ACROSS MUCH OF THE AREA, A FEW SPRINKLES OR BRIEF LIGHT RAIN
SHOWERS CANNOT BE RULED OUT ESPECIALLY ACROSS THE NORTHERN AREAS.
GIVEN THE AMOUNT OF DRYNESS TO THE AIR MASS, OPTED TO NOT BOOST THE
RATHER LOW NBM POPS AS OF NOW.
THE UPPER-LEVEL TROUGH IS FORECAST TO REMAIN IN PLACE ON THURSDAY,
ALTHOUGH THE INITIAL AXIS LIFTS TO OUR NORTHEAST WITH A SECONDARY
ONE APPROACHING FROM THE GREAT LAKES. SOME CLOUDS SHOULD INCREASE
AHEAD OF THIS NEXT TROUGH AXIS. A COLD FRONT APPROACHES FROM THE
WEST DURING THE DAY BEFORE ARRIVING AT NIGHT AS LOW PRESSURE TRACKS
TO OUR NORTH. SOME SHOWER ACTIVITY MAY START TO ARRIVE LATER AT
NIGHT AS SOME MOISTURE RETURN OCCURS AHEAD OF THE COLD FRONT AS
WINDS BACK TO SOUTHWESTERLY. OVERALL THOUGH, THE MOISTURE RETURN
DOES NOT LOOK ALL THAT ROBUST. TEMPERATURES THROUGH THIS ENTIRE
TIMEFRAME ARE FORECAST TO BE ON THE COOLER SIDE (AT OR BELOW
AVERAGE).
LONG TERM /FRIDAY THROUGH MONDAY/
SUMMARY...TEMPERATURES NEAR OR BELOW AVERAGE; SOME LOW CHANCES FOR
SHOWERS OR THUNDERSTORMS TO START.
SYNOPTIC OVERVIEW...A STRONG UPPER-LEVEL TROUGH IS FORECAST TO SWING
ACROSS THE NORTHEAST AND MID-ATLANTIC REGIONS FRIDAY AND SATURDAY,
THEN WEAKEN AND LIFT OUT SUNDAY INTO MONDAY. A TROUGH ALOFT THOUGH
IS FORECAST TO LINGER ACROSS OUR REGION INTO EARLY NEXT WEEK. AT THE
SURFACE, A COLD FRONT WORKS OFFSHORE FRIDAY FOLLOWED BY HIGH
PRESSURE CENTERED ACROSS THE GREAT LAKES THAT BUILDS MORE INTO OUR
AREA INTO EARLY NEXT WEEK.
FOR FRIDAY...A STRONG UPPER-LEVEL TROUGH IS FORECAST TO SWING ACROSS
THE NORTHEAST AND MID-ATLANTIC REGIONS. THE GUIDANCE IS IN GOOD
AGREEMENT REGARDING THE PRESENCE OF THIS TROUGH, WITH MOST OF THE
GUIDANCE INCLUDING ENSEMBLES SHOWING A CLOSED LOW EVOLVING NORTH OF
LAKE ONTARIO. THIS TROUGH WILL DRIVE A COLD FRONT ACROSS OUR AREA
DURING FRIDAY. THE TIMING MAY BE FAST ENOUGH TO NOT OCCUR DURING
PEAK HEATING AND THUS LIMITING THE POTENTIAL CONVECTIVE COVERAGE. IN
ADDITION, MOISTURE RETURN COULD BE MORE LIMITED AND THUS ALSO A MORE
DRIER ENVIRONMENT FOR STRONGER CONVECTION. A COOLER AND MUCH DRIER
AIR MASS THEN SETTLES IN FOLLOWING THE COLD FRONT THROUGH FRIDAY
NIGHT.
FOR SATURDAY THROUGH MONDAY...THE AFOREMENTIONED STRONG UPPER-LEVEL
TROUGH IS FORECAST TO WEAKEN AND GRADUALLY LIFT OUT INTO EARLY NEXT
WEEK. THE GUIDANCE SUGGESTS THAT A TROUGH ALOFT HOWEVER DOES LINGER
ACROSS OUR REGION, ALTHOUGH THERE ARE SOME DIFFERENCES IN THE
STRENGTH OF THIS WITHIN THE MODELS/ENSEMBLES. AT THE SURFACE, HIGH
PRESSURE CENTERED OVER THE GREAT LAKES REGION IS FORECAST TO EXPAND
EASTWARD AND WILL ALSO EXTEND INTO OUR AREA. TEMPERATURES ARE
FORECAST TO HANG OUT AT OR BELOW AVERAGE WITH DEW POINTS IN THE 40S
AND 50S. GIVEN THE DRIER AIR MASS FORECAST TO BE PLACE ALONG WITH
THE MUCH WEAKER TROUGH ALOFT, A DRY FORECAST IS CURRENTLY ADVERTISED
FOR THE HOLIDAY/LABOR DAY WEEKEND.
AVIATION /08Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THRU 12Z...VFR. WEST TO NORTHWEST WINDS DIMINISHING TO AROUND 5
KNOTS. HIGH CONFIDENCE.
TODAY AND TONIGHT...MAINLY VFR. SMALL CHANCE OF AN ISOLATED
SHOWER IN THE AFTERNOON AND EVENING, MAINLY FOR KRDG/KABE, BUT
CONFIDENCE STILL A LITTLE LOW TO ADD TO TAFS. WEST WINDS AROUND
5 TO 10 KNOTS, BECOMING NORTHWEST TONIGHT. MODERATE CONFIDENCE.
OUTLOOK...
WEDNESDAY AND THURSDAY...VFR.
FRIDAY...SOME SHOWERS AND THUNDERSTORMS POSSIBLE, OTHERWISE MAINLY
VFR.
SATURDAY...VFR.
MARINE
CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS
TODAY AND TONIGHT AS SEAS WILL BE AROUND 3 TO 4 FEET AND NW
WINDS SHIFTING TO SW THIS AFTERNOON WILL BE AROUND 10 KNOTS,
SHIFTING BACK NW TONIGHT.
OUTLOOK...
WEDNESDAY THROUGH SATURDAY...THE CONDITIONS ARE ANTICIPATED TO BE
BELOW SMALL CRAFT ADVISORY CRITERIA.
RIP CURRENTS...
FOR TODAY, NORTHWESTERLY WINDS 5-10 MPH IN THE MORNING WILL
BECOME SOUTHWESTERLY AROUND 10 MPH IN THE AFTERNOON. BREAKING
WAVE HEIGHTS 2-3 FEET. EAST-SOUTHEASTERLY SWELL AROUND 2-3 FEET
AT 7-9 SECONDS IN LENGTH. AS A RESULT, HAVE OPTED TO MAINTAIN A
MODERATE RISK FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS AT
ALL BEACHES.
FOR WEDNESDAY, NORTHWESTERLY WINDS AROUND 5-10 MPH REMAIN
THROUGH MUCH OF THE DAY. BREAKING WAVE HEIGHTS WILL BE AROUND
1-2 FEET WITH A FEW 3 FOOT WAVES POSSIBLE NORTH. EASTERLY SWELL
WILL DIMINISH TO AROUND 1-2 FEET AROUND 7-9 SECONDS IN LENGTH.
GUIDANCE SUGGESTS MARGINALLY HIGHER SEAS AND SWELL FOR COASTAL
ATLANTIC AND NORTH, SO WENT WITH A MODERATE RISK FOR THIS REGION
WITH A LOW RISK FOR COASTAL CAPE MAY NJ AND SUSSEX DE.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...GORSE
NEAR TERM...RCM
SHORT TERM...GORSE
LONG TERM...GORSE
AVIATION...GORSE/RCM
MARINE...GORSE/MJL/RCM
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