485
FXUS61 KPHI 270643
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
243 AM EDT WED AUG 27 2025
SYNOPSIS
HIGH PRESSURE, CENTERED IN THE OHIO VALLEY THIS MORNING, WILL SLIDE
EASTWARD ACROSS THE MID-ATLANTIC LATER TODAY INTO TONIGHT BEFORE
SHIFTING OFFSHORE THURSDAY. A COLD FRONT THEN CROSSES OUR AREA LATER
THURSDAY NIGHT INTO FRIDAY, FOLLOWED BY HIGH PRESSURE OVER THE
WEEKEND. AN AREA OF LOW PRESSURE MAY DEVELOP OFF THE MID-ATLANTIC
COAST EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
HIGH PRESSURE OVER THE OHIO VALLEY WILL BUILD EASTWARD THROUGH
THE NEXT 24 HOURS, ENDING UP ACROSS THE MID-ATLANTIC BY LATE
TONIGHT. ALOFT, UPPER TROUGH CURRENTLY OVERHEAD, CENTERED JUST
TO OUR WEST PRESENTLY, WILL SLIDE EAST AND START LIFTING OUT BY
THIS AFTERNOON, A PROCESS WHICH WILL CONTINUE TONIGHT. THUS,
OVERALL EXPECT A RELATIVELY TRANQUIL DAY, WITH LESS CHANCE OF
SPOTTY SHOWERS COMPARED TO YESTERDAY, THOUGH INSTABILITY
ASSOCIATED WITH THE LINGERING UPPER TROUGH MAY STILL SPAWN
SOMETHING, MOST LIKELY OVER THE POCONOS OR FAR NW NJ. OTHERWISE,
SOME HIGH CLOUDS THIS MORNING WILL GIVE WAY TO JUST SOME SPOTTY
CUMULUS LATER ON TODAY, WITH A BIT OF A BREEZY NORTHWEST WIND IN
THE WAKE OF YESTERDAY'S REINFORCING COLD FRONT. HIGHS IN MOST OF
THE AREA WILL FAIL TO REACH 80, A RARE EVENT ON WHAT OTHERWISE
SHOULD BE A MOSTLY SUNNY AND DRY LATE AUGUST DAY.
HIGH PRESSURE NEARBY WILL PROMOTE LIGHT WINDS, CLEAR SKIES AND
GOOD RADIATIONAL COOLING TONIGHT. THUS, EXPECT THE COOLEST NIGHT
OF THE MONTH ACROSS THE REGION, WITH 40S IN THE COLDEST SPOTS,
MOST OTHER LOCALES IN THE 50S, AND MAYBE A FEW 60S IN THE
ABSOLUTELY WARMEST URBAN AREAS AND NEAR THE IMMEDIATE COAST.
THAT SAID, IT LOOKS LIKE WE WON'T REACH RECORDS, WHICH ARE AT
LEAST 5 DEGREES BELOW THE CURRENT FORECAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
AN UPPER-LEVEL TROUGH IS FORECAST TO AMPLIFY INTO THE NORTHEAST AND
MID-ATLANTIC REGIONS THURSDAY. A COLD FRONT APPROACHES FROM THE WEST
DURING THE DAY BEFORE ARRIVING THURSDAY NIGHT AS LOW PRESSURE TRACKS
TO OUR NORTH. A FEW SHOWERS MAY START TO ARRIVE BY LATER AT NIGHT
ACROSS THE WESTERN AREAS AS SOME MOISTURE RETURN CONTINUES AHEAD OF
THE COLD FRONT. OVERALL THOUGH, THE MOISTURE RETURN DOES NOT LOOK
ALL THAT ROBUST AND THE MAIN FORCING SLIDING BY TO OUR NORTH SHOULD
LIMIT THE AMOUNT OF SHOWERS STARTING TO ARRIVE FROM THE WEST.
TEMPERATURES ARE FORECAST TO BE ON THE COOLER SIDE (BELOW AVERAGE).
FOR FRIDAY, A STRONG UPPER-LEVEL TROUGH SWINGS ACROSS THE NORTHEAST
AND MID-ATLANTIC REGIONS. THE GUIDANCE IS IN GOOD AGREEMENT
REGARDING THE PRESENCE OF THIS TROUGH, WITH MOST OF THE GUIDANCE
SHOWING A CLOSED LOW EVOLVING NORTH OF LAKE ONTARIO. THIS TROUGH
WILL CONTINUE TO DRIVE A COLD FRONT ACROSS OUR AREA. THE TIMING MAY
BE FAST ENOUGH TO NOT OCCUR DURING PEAK HEATING AND THUS LIMITING
THE COVERAGE OF SHOWERS/THUNDER. IN ADDITION, THE MOISTURE RETURN IS
NOT ALL THAT ROBUST AND WITH THE STRONGER FORCING SLIDING BY TO OUR
NORTH, THE CHANCES FOR ANY SHOWERS/THUNDER IS ON THE LOW SIDE (20-30
PERCENT). TEMPERATURES MOSTLY BELOW AVERAGE, AND DEW POINTS INCREASE
AHEAD OF THE FRONT WELL INTO THE 50S BEFORE FALLING THROUGH THE 50S
AND INTO THE 40S AT NIGHT IN THE WAKE OF THE COLD FRONT.
LONG TERM /SATURDAY THROUGH TUESDAY/
SUMMARY...TEMPERATURES MOSTLY BELOW AVERAGE; MAY NEED TO WATCH FOR A
POSSIBLE COASTAL LOW EARLY NEXT WEEK.
SYNOPTIC OVERVIEW...A STRONG UPPER-LEVEL TROUGH IS FORECAST TO SWING
ACROSS THE NORTHEAST AND MID-ATLANTIC REGIONS SATURDAY. THIS SHOULD
BE IN THE FORM OF A CLOSED LOW AS IT PIVOTS ACROSS NEW ENGLAND, THEN
OPENS UP AS IT SHIFTS INTO THE CANADIAN MARITIMES THROUGH SUNDAY. A
TROUGH ALOFT THOUGH IS FORECAST TO EXTEND ACROSS OUR REGION INTO
EARLY NEXT WEEK. SOME GUIDANCE HAS SOME STRONGER ENERGY HANGING BACK
ACROSS THE OHIO VALLEY WHICH THEN POTENTIALLY RESULTS IN A CLOSED
LOW ACROSS THE MID-ATLANTIC MONDAY INTO TUESDAY. AT THE SURFACE, A
COLD FRONT IS FORECAST TO BE WELL OFFSHORE TO START SATURDAY WITH
HIGH PRESSURE BUILDING EASTWARD FROM THE MIDWEST AND GREAT LAKES.
THE HIGH SLIDES BY TO OUR NORTH DURING EARLY NEXT WEEK AS A LOW
PRESSURE SYSTEM MAY DEVELOP OFF THE MID-ATLANTIC COAST.
FOR SATURDAY AND SUNDAY....A STRONG UPPER-LEVEL TROUGH, AS A CLOSED
LOW OVER NEW ENGLAND, IS FORECAST TO WEAKEN AS IT SHIFTS MORE INTO
THE CANADIAN MARITIMES. THIS ALLOWS SURFACE HIGH PRESSURE CENTERED
FROM THE MIDWEST AND GREAT LAKES TO SHIFT EASTWARD SOME AND MORE
INTO OUR AREA. THE GUIDANCE OVERALL KEEPS A TROUGH ALOFT THOUGH
EXTENDED ACROSS OUR AREA AND BACK INTO THE OHIO VALLEY. OUR SENSIBLE
WEATHER LOOKS TO BE CONTROLLED MAINLY BY HIGH PRESSURE CENTERED TO
OUR NORTHWEST AND THEREFORE A DRY HOLIDAY WEEKEND IS MAINTAINED.
SOME OF THE GUIDANCE/ENSEMBLES SUGGEST THAT THE TAIL-END OF THE
TROUGH ALOFT STRENGTHENS AND STARTS TO CLOSE OFF DURING SUNDAY IN
THE VICINITY OF THE CENTRAL APPALACHIANS. AS THIS OCCURS, LOWERING
HEIGHTS RESULTS IN A LINGERING BAROCLINIC ZONE OFF THE SOUTHEAST
U.S. COAST TO START STRENGTHENING AND SURFACE LOW PRESSURE MAY BEGIN
TO DEVELOP. SOME HIGH LEVEL CLOUDS MAY THEN START TO ARRIVE IN OUR
AREA AS WE GO THROUGH SUNDAY. DAYTIME TEMPERATURES ARE FORECAST TO
BE IN THE 70S BOTH DAYS FOR MOST OF THE AREA, WITH LOWS MOSTLY IN
THE 50S.
FOR MONDAY AND TUESDAY...AS THE AFORMENTIONED TROUGH ALOFT BECOMES
POTENTIALLY A CLOSED LOW TO OUR SOUTHWEST INITIALLY, LOW PRESSURE
OFF THE MID-ATLANTIC COAST WOULD TEND TO TRACK TO THE NORTH OR
NORTHEAST. THIS COULD BRING SOME SHOWERS TO AT LEAST THE COASTAL
AREAS STARTING LATER MONDAY (LABOR DAY). THE EVOLUTION OF THIS
SYSTEM IS UNCERTAIN GIVEN THE SPREAD WITHIN THE MODEL GUIDANCE AND
ENSEMBLE DATA. THERE IS AT LEAST SOME SIGNAL THOUGH IN THE GUIDANCE
OF A COASTAL LOW TRACKING TO THE NORTH OR NORTHEAST DURING THIS TIME
FRAME, HOWEVER THE IMPACTS TO OUR AREA ARE MUCH LESS CERTAIN.
DESPITE IF SHOWERS OCCUR OR NOT, TEMPERATURES STILL LOOK TO BE NEAR
OR BELOW AVERAGE ACROSS THE REGION. GIVEN THE UNCERTAINTY ON WHETHER
A COASTAL LOW OCCURS OR NOT AND THE TRACK IF IT DOES DEVELOP,
CONTINUED TO RIDE WITH THE NATIONAL BLEND OF MODELS (NBM)
OUTPUT.
AVIATION /07Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THRU 12Z...VFR. PATCHY FOG WITH LOWER VSBYS POSSIBLE KRDG.
NORTHWEST WINDS AROUND 5 TO 10 KNOTS. HIGH CONFIDENCE.
TODAY...VFR WITH WNW WINDS AROUND 10 KNOTS; A FEW GUSTS MAY
REACH 20 KTS IN THE MIDDAY AND AFTERNOON. HIGH CONFIDENCE.
TONIGHT...VFR WITH WNW WINDS TAPERING TO 5 KTS OR LESS. HIGH
CONFIDENCE.
OUTLOOK...
THURSDAY...VFR.
FRIDAY...A FEW SHOWERS OR A THUNDERSTORM POSSIBLE, OTHERWISE MAINLY
VFR.
SATURDAY AND SUNDAY...VFR.
MARINE
CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS
THRU TONIGHT AS SEAS WILL BE AROUND 2 TO 3 FEET AND WNW WINDS
WILL BE AROUND 10 KNOTS WITH A FEW GUSTS UP TO 20 KTS.
OUTLOOK...
THURSDAY THROUGH SUNDAY...THE CONDITIONS ARE ANTICIPATED TO BE BELOW
SMALL CRAFT ADVISORY CRITERIA.
RIP CURRENTS...
FOR TODAY, NORTHWESTERLY WINDS AROUND 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 THURSDAY, WINDS SHIFT SOUTHERLY BUT REMAIN AROUND 10 MPH
THROUGH MUCH OF THE DAY. BREAKING WAVE HEIGHTS WILL REMAIN
AROUND 1-2 FEET WITH A FEW 3 FOOT WAVES POSSIBLE NORTH. EASTERLY
SWELL WILL REMAIN AROUND 1-2 FEET AROUND 7-9 SECONDS IN LENGTH.
GUIDANCE STILL SUGGESTS MARGINALLY HIGHER SEAS AND SWELL FOR
COASTAL ATLANTIC AND NORTH, SO AGAIN 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/RCM
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