885
FXUS61 KPHI 071959
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
259 PM EST SAT MAR 7 2026
WHAT HAS CHANGED
MARINE DENSE FOG ADVISORIES HAVE BEEN EXTENDED UNTIL 6 AM
SUNDAY FOR ALL ATLANTIC COASTAL WATERS INCLUDING THE DELAWARE
BAY.
KEY MESSAGES
1. LOCALIZED DENSE FOG POSSIBLE TONIGHT, ESPECIALLY ALONG THE
NJ COAST.
2. A COUPLE OF FRONTS WILL IMPACT THE REGION THROUGH SUNDAY
WITH CONTINUED CHANCES FOR SHOWERS AND POSSIBLY SOME
THUNDERSTORMS.
3. WARMER AIR WILL OVERSPREAD THE REGION EARLY NEXT WEEK, WITH
A COUPLE CHANCES FOR SHOWERS AND FOG.
DISCUSSION
KEY MESSAGE 1...LOCALIZED DENSE FOG POSSIBLE TONIGHT,
ESPECIALLY ALONG THE NJ COAST.
A STABLE AIRMASS REMAINS ENTRENCHED OVER THE ENTIRE FORECAST
AREA WITH LOW STRATUS. WHILE A STRONG WARM AIR ADVECTION REGIME
IS EXPECTED TO TAKE PLACE OVERNIGHT, THERE REMAINS A STRONG LOW-
LEVEL INVERSION KEEPING MOISTURE TRAPPED AT/NEAR THE SURFACE.
THIS IS SPECIFICALLY ENHANCED NEAR COASTAL AREAS WHERE COLD AIR
OFF THE CHILLY ATLANTIC WATERS STEEPENS THE INVERSION COMPARED
TO FURTHER INLAND. HREF PROBABILITIES SUGGEST THERE IS ROUGHLY A
60%+ CHANCE OF VISIBILITIES ONE-QUARTER OF A MILE OR LESS
TONIGHT FOR COASTAL AREAS OF NJ. THESE PROBABILITIES THEN DROP
DRASTICALLY TO ROUGHLY 10-20% FURTHER INLAND.
WITH THIS BEING SAID, IT IS FAIRLY CONFIDENT THERE WILL BE AT
LEAST SOME DENSE FOG NEAR THE NJ COAST TONIGHT. HOWEVER, THE
OVERALL DURATION IS LESS CERTAIN WITH THE TIMING OF THE WARM AIR
ADVECTION PUSH AND THE OVERALL EXTENT INLAND. FOR THIS REASON,
HAVE OPTED TO LET THE EVENING SHIFT EVALUATE AND ISSUE
ADVISORIES AS NEEDED.
KEY MESSAGE 2...A COUPLE OF FRONTS WILL IMPACT THE REGION
THROUGH SUNDAY WITH CONTINUED CHANCES FOR SHOWERS AND POSSIBLY
SOME THUNDERSTORMS.
HIGH PRESSURE OVER EASTERN CANADA CONTINUES TO SHIFT AWAY THIS
AFTERNOON. MEANWHILE, THE BACK-DOOR FRONT THAT IS CURRENTLY
SITUATED OVER CENTRAL PA DOWN INTO CENTRAL AND EASTERN VA WILL
BEGIN TO LIFT BACK NORTH LATER TODAY. THIS WARM FRONT IS NOT
PROGGED TO REACH OUR AREA UNTIL AT LEAST THIS EVENING FOR THE
DELMARVA, NEAR PHILLY UNTIL AROUND/AFTER MIDNIGHT, AND ACROSS
NORTHERN AREAS BY THE PRE-DAWN HOURS SUNDAY MORNING. A COLD
FRONT WILL THEN BE QUICKLY ON ITS HEELS TRACKING THROUGH EARLY
TO MID-DAY ON SUNDAY FROM NORTHWEST TO SOUTHEAST.
IN TERMS OF SHOWERS, THE REST OF TODAY SHOULD BE FAIRLY DRY.
FOR TONIGHT, SHOWERS AND T-STORMS ASSOCIATED WITH A PRE-FRONTAL
TROUGH (BRINGING THE SEVERE WEATHER TO E OH AND W PA TODAY) WILL
BE TRACKING ACROSS CENTRAL PA THIS EVENING. AS THIS LINE
PROGRESSES EAST OVERNIGHT, THE LINE SHOULD WEAKEN AND DECAY AS
IT RUNS INTO THE COOLER AND MORE STABLE AIRMASS (DENOTED IN KEY
MESSAGE 1). ALTHOUGH THESE SHOWERS MAY OUTRUN THE STRONGEST
FORCING, THERE REMAINS AN ELEVATED POTENTIAL FOR INSTABILITY, SO
CANNOT COMPLETELY RULE OUT A T-STORM OR TWO TONIGHT. BEST
CHANCES WILL BE FURTHER NORTH AND WEST OVER BERKS CO, THE LEHIGH
VALLEY AND POCONOS, BUT NO SEVERE WEATHER IS EXPECTED.
ELSEWHERE, JUST SOME SHOWERS ARE POSSIBLE TONIGHT. TEMPERATURES
TONIGHT WILL START OFF IN THE 40S, BUT RISE OVERNIGHT INTO THE
50S ONCE THE WARM FRONT CLEARS. COME SUNDAY, BETTER FORCING
ARRIVES WITH THE ACTUAL COLD FRONT. WITH MUCH OF THE AREA IN THE
WARM-SECTOR BY THIS POINT, THERE MAY BE SOME RE-DEVELOPMENT
ALONG THE FRONT ITSELF DEPENDING ON HOW FAST THE FRONT
PROGRESSES THROUGH THE AREA. THUS, FOR AREAS SOUTH AND WEST OF
I-95, ESPECIALLY ACROSS THE DELMARVA, THERE MAY BE A POTENTIAL
FOR ADDITIONAL SHOWERS AND T- STORMS LATE SUNDAY MORNING INTO
EARLY AFTERNOON. AGAIN, NO SEVERE THREAT IS EXPECTED AND ANY
SHOWERS/STORMS WILL MOVE OFFSHORE BY MID- AFTERNOON. HIGH TEMPS
WILL TOP OUT IN THE 60S FOR MUCH OF THE AREA, WITH 50S IN THE
POCONOS AND POSSIBLY TOUCHING 70 ACROSS SOUTHERN DE.
KEY MESSAGE 3...WARMER AIR WILL OVERSPREAD THE REGION EARLY
NEXT WEEK, WITH A COUPLE CHANCES FOR SHOWERS AND FOG.
THE REGION WILL BE BENEATH A FAIRLY BENIGN UPPER PATTERN FROM
SUNDAY NIGHT THROUGH TUESDAY NIGHT. AT THE SURFACE, HIGH
PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF SUNDAY'S
FRONTAL PASSAGE. AS THE HIGH GRADUALLY SHIFTS EASTWARD THROUGH
TUESDAY NIGHT, LIGHT RETURN FLOW IS EXPECTED TO COMMENCE,
BRINGING ABOUT A WARMING TREND. LOWS SUNDAY NIGHT WILL LIKELY BE
IN THE UPPER 30S TO MID 40S ACROSS THE ENTIRE AREA. ON MONDAY,
WITH LIGHT SOUTHERLY FLOW AND AT LEAST SOME SUNSHINE,
TEMPERATURES ARE EXPECTED TO RISE INTO THE 60S ACROSS MOST OF
THE AREA. THE WARMING TREND WILL CONTINUE THROUGH WEDNESDAY WITH
HIGHS WARMING INTO THE LOW TO MID 70S AND LOWS IN THE 40S AND
50S. HIGHS MAY BE COOLER IN PROXIMITY TO THE OCEAN DUE TO
POTENTIAL SEA BREEZE DEVELOPMENT EACH DAY. IN ADDITION, THERE IS
THE POTENTIAL FOR FOG EACH NIGHT. RELATIVELY LIGHT WINDS IN
COMBINATION WITH WARM AND MOIST AIR OVERSPREADING THE REGION
WITH VERY COOL OCEAN TEMPERATURES COULD LEAD TO DENSE FOG,
PARTICULARLY NEAR THE COASTS.
BEGINNING ON WEDNESDAY, THE UPPER PATTERN WILL BECOME MUCH MORE
UNSETTLED AS A POTENT TROUGH OVER CENTRAL PORTIONS OF THE US
BEGINS TO WORK EASTWARD TOWARDS OUR AREA. BROAD ASCENT IS LIKELY
TO BEGIN OVERSPREADING THE REGION DURING THIS TIME, AND WILL
LEAD TO A CHANCE FOR SCATTERED SHOWERS WITHIN THE WARM AIR
ADVECTION REGIME. ON WEDNESDAY, SHOWER ACTIVITY APPEARS MOST
LIKELY ALONG AND NORTH OF I- 95, WITH POPS CURRENTLY IN THE
20-40% RANGE. WEDNESDAY NIGHT, SHOWERS MAY HAVE A TENDENCY TO
BECOME MORE WIDESPREAD OVER THE ENTIRE REGION.
THE TROUGH AXIS IS EXPECTED TO SHIFT EASTWARD ACROSS THE REGION
SOMETIME ON THURSDAY. A SURFACE LOW AND TRAILING COLD FRONT
WILL LIKELY ACCOMPANY IT. ALONG AND AHEAD OF THE COLD FRONT ON
THURSDAY, POPS INCREASE TO 50-70% AREAWIDE. MOST GUIDANCE
FEATURES A LINE OF SHOWERS MOVING THROUGH THE REGION. VERY
STRONG WIND FIELDS ALOFT AND AT LEAST MODEST INSTABILITY ARE
FORECAST TO BE PRESENT, SO THUNDERSTORMS WILL BE POSSIBLE. AFTER
THE FRONTAL PASSAGE, SOME LINGERING RAIN OR SNOW SHOWERS WILL
BE POSSIBLE ACROSS THE AREA AS COLDER AIR FILTERS INTO THE
REGION.
COOLER TEMPERATURES ARE EXPECTED FRIDAY AND INTO THE FIRST PART
OF THE WEEKEND. ANOTHER WEAK SYSTEM MAY GLANCE THE REGION
FRIDAY NIGHT, BRINGING A CHANCE FOR LIGHT RAIN AND PERHAPS A
LITTLE SNOW IN THE POCONOS, BUT IT IS POSSIBLE THAT THE SYSTEM
WILL PASS TO OUR NORTH KEEPING THE REGION DRY. FOR NOW, WILL
FEATURE 20-30% POPS DURING THIS TIME PERIOD, WITH THE HIGHER
CHANCES BEING ACROSS NORTHERN PORTIONS OF THE AREA.
AVIATION /19Z SATURDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY...MVFR/IFR CEILINGS EXPECTED. POSSIBLE SPOTTY
MIST AND FOG AFTER 22Z SO OPTED TO INCLUDE TEMPOS WHERE NEEDED.
SOUTH WINDS AROUND 5-10 KT. MODERATE CONFIDENCE OVERALL.
TONIGHT...IFR/LIFR (POSSIBLY VLIFR AT TIMES) WITH LOW CEILINGS
AND VISIBILITY RESTRICTIONS. RAIN SHOWERS MOVE IN FROM WEST TO
EAST BETWEEN 00-03Z FOR THE LEHIGH VALLEY TERMINALS AND I-95
TERMINALS BETWEEN 03-06Z. LLWS LIKELY AT ALL TERMINALS BETWEEN
00-10Z OUT OF THE SOUTHWEST AT AROUND 40-50 KT. POSSIBLE
CLEARING AT MIV AND ILG LATE, BUT CONFIDENCE IS LOW. OVERALL,
MODERATE-LOW CONFIDENCE.
SUNDAY...LINGERING IFR/LIFR CONDITIONS EARLY, SHOULD GRADUALLY
IMPROVE TO MVFR BETWEEN 12-15Z WITH SHOWERS ENDING. THE
EXCEPTION IS MIV AND ACY WHERE SHOWERS MAY LINGER INTO THE
AFTERNOON HOURS. OVERALL, A GRADUAL IMPROVEMENT IS EXPECTED WITH
VFR CONDITIONS RETURNING BY THE AFTERNOON FROM NORTHWEST TO
SOUTHEAST. WEST WINDS AROUND 10-15 KT WITH OCCASIONAL GUSTS UP
TO 20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE.
OUTLOOK...
SUNDAY NIGHT THROUGH TUESDAY NIGHT...PRIMARILY VFR. PERIODS OF
SUB- VFR CONDITIONS WILL BE POSSIBLE IN FOG EACH NIGHT.
WEDNESDAY THROUGH WEDNESDAY NIGHT...SUB-VFR CONDITIONS POSSIBLE
IN RAIN SHOWERS.
THURSDAY...SUB-VFR CONDITIONS EXPECTED IN WIDESPREAD SHOWERS.
SOME THUNDER IS POSSIBLE.
MARINE
MARINE DENSE FOG ADVISORIES HAVE BEEN EXTENDED UNTIL 6 AM
SUNDAY FOR ALL ATLANTIC COASTAL WATERS INCLUDING THE DELAWARE
BAY. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FROM 7 PM THIS
EVENING UNTIL 6 PM SUNDAY FOR THE ATLANTIC COASTAL WATERS ONLY.
SOUTH-SOUTHWEST WINDS STEADILY INCREASE TONIGHT WITH GUSTS UP
TO 25 KT POSSIBLE. SOUTHWEST WINDS WILL THEN REMAIN AROUND 15-20
KT THROUGH SUNDAY AFTERNOON BEFORE SHIFTING WEST AROUND 10-15
KT IN WAKE OF FRONTAL PASSAGE. SEAS AROUND 4-6 FEET.
A CHANCE OF SHOWERS TONIGHT, BECOMING LIKELY ON SUNDAY WITH A
SLIGHT CHANCE FOR THUNDERSTORMS. DENSE MARINE FOG LIKELY
TONIGHT, POSSIBLY LINGERING INTO SUNDAY AS WELL.
OUTLOOK...
SUNDAY NIGHT...SCA CONDITIONS MAY LINGER INTO THE EVENING HOURS
IN THE FORM OF ELEVATED SEAS, BUT SHOULD QUICKLY BECOME SUB-SCA
WITH SEAS 2-4 FEET. MARINE FOG IS POSSIBLE.
MONDAY THROUGH TUESDAY NIGHT...SUB-SCA CONDITIONS EXPECTED WITH
WINDS UNDER 25 KT AND SEAS UNDER 5 FEET. MARINE FOG IS POSSIBLE
MONDAY AND TUESDAY NIGHT.
WEDNESDAY THROUGH THURSDAY...SCA CONDITIONS EXPECTED. GALES ARE
POSSIBLE ON THURSDAY. SOUTHERLY WINDS 10-15 KT WITH GUSTS TO 25
KT ARE EXPECTED WEDNESDAY INTO WEDNESDAY NIGHT. SOUTHWESTERLY
WINDS 20- 25 KT WITH GUSTS 30-35 KT EXPECTED THURSDAY, BEFORE
BECOMING WEST- NORTHWESTERLY BEHIND A COLD FRONT THURSDAY
AFTERNOON. SEAS 4-7 FEET ON WEDNESDAY WILL INCREASE TO 5-9 FEET
WEDNESDAY NIGHT INTO THURSDAY. SHOWERS ARE LIKELY, PARTICULARLY
ON THURSDAY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ430-431-
450>455.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR ANZ450>455.
DISCUSSION...COOPER/DESILVA
AVIATION...COOPER/DESILVA
MARINE...COOPER/DESILVA
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