640
FXUS61 KPHI 030824
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
424 AM EDT FRI APR 3 2026
WHAT HAS CHANGED
FOG POSSIBLE AGAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING.
KEY MESSAGES
1. THE MARINE LAYER WILL REMAIN IN PLACE ACROSS THE REGION
THROUGH THIS MORNING, THEN SCATTER OUT THIS AFTERNOON.
WIDESPREAD FOG DEVELOPMENT IS EXPECTED THIS MORNING, ALONG WITH
CONTINUED COLD AND DAMP CONDITIONS. THERE IS THE POTENTIAL FOR
DENSE FOG. WARMER AND DRIER CONDITIONS THEN RETURN FOR THE
SECOND HALF OF TODAY.
2. A WARM FRONT LIFTS NORTH OF THE REGION SATURDAY BRINGING
RECORD-CHALLENGING WARMTH ACROSS THE REGION BEFORE A COLD FRONT
CROSSES SUNDAY, BRINGING A FEW ROUNDS OF SHOWERS AND
THUNDERSTORMS BEFORE USHERING IN MORE SEASONABLE TEMPERATURES.
DISCUSSION
KEY MESSAGE 1...THE MARINE LAYER WILL REMAIN IN PLACE ACROSS THE
REGION THROUGH THIS MORNING, THEN SCATTER OUT THIS AFTERNOON.
WIDESPREAD FOG DEVELOPMENT IS EXPECTED THIS MORNING, ALONG WITH
CONTINUED COLD AND DAMP CONDITIONS. THERE IS THE POTENTIAL FOR DENSE
FOG. WARMER AND DRIER CONDITIONS THEN RETURN FOR THE SECOND HALF OF
TODAY.
HIGH PRESSURE OVER THE CANADIAN MARITIMES EARLY THIS MORNING WILL
EXIT OFF TO THE NORTHEAST THROUGH THE MORNING HOURS. DURING THIS
TIMEFRAME, A LOW PRESSURE SYSTEM MOVING NORTHEAST OUT OF THE MIDWEST
WILL MOVE INTO CANADA WHICH ALLOWS OUR STATIONARY FRONT SOUTH OF THE
AREA TO MAKE PROGRESS NORTHWARD AS A WARM FRONT. THE WARM FRONT
LOOKS TO CLEAR THE AREA BY EARLY AFTERNOON.
FOR THIS MORNING, IT WILL REMAIN COOL AND DAMP AS THE MARINE LAYER
IS STILL IN PLACE ACROSS THE REGION. PLENTY OF LOW CLOUDS WILL BE
AROUND DURING THE MORNING HOURS WITH FOG ALSO DEVELOPING AS MOISTURE
IS TRAPPED BELOW A LOW-LEVEL INVERSION. THERE IS THE POTENTIAL FOR
DENSE FOG TO DEVELOP. TEMPERATURES THROUGH THE MORNING WILL BE
MAINLY IN THE 40S AND 50S.
IMPROVEMENTS ARE EXPECTED THIS AFTERNOON AS THE WARM FRONT CLEARS
THE AREA. AS THE INVERSION BREAKS DOWN THIS AFTERNOON, CLOUDS
DECREASE IN COVERAGE, ANY FOG DIMINISHES, AND WE QUICKLY WARM UP.
WINDS TURN FROM BEING OUT OF THE EAST IN THE MORNING TO OUT OF THE
SOUTHWEST THIS AFTERNOON. THE WARM AIR MOVING IN ALLOWS MANY
LOCATIONS TO REACH INTO THE 70S FOR HIGHS TODAY.
THIS EVENING, A PREFRONTAL TROUGH LOOKS TO MOVE IN FROM THE WEST
AHEAD OF A COLD FRONT. AN ISOLATED SHOWER IS POSSIBLE LATE THIS
EVENING INTO EARLY TONIGHT AND PERHAPS A RUMBLE OF THUNDER.
OVERNIGHT, WINDS ARE RELATIVELY LIGHT AND THERE IS A SIGNAL FOR
ANOTHER LOW-LEVEL INVERSION BRIEFLY DEVELOPING TOWARDS DAYBREAK
TOMORROW. SOME LOW-LEVEL MOISTURE LOOKS TO GET TRAPPED BENEATH THIS
INVERSION LEADING TO THE POTENTIAL FOR SOME FOG DEVELOPMENT. LOWS
TONIGHT ARE IN THE MID 50S TO LOW 60S FOR MOST.
KEY MESSAGE 2...A WARM FRONT LIFTS NORTH OF THE REGION SATURDAY
BRINGING RECORD-CHALLENGING WARMTH ACROSS THE REGION BEFORE A
COLD FRONT CROSSES SUNDAY, BRINGING A FEW ROUNDS OF SHOWERS AND
THUNDERSTORMS BEFORE USHERING IN MORE SEASONABLE TEMPERATURES.
A WARM FRONT IS EXPECTED TO LIFT NORTH THROUGH THE REGION ON
SATURDAY AS LOW PRESSURE BEGINS TO SHIFT NORTHEASTWARD OUT OF
THE GREAT LAKES REGION. SCATTERED SHOWERS WILL BE POSSIBLE IN
THE VICINITY OF THE FRONT THROUGH THE DAY SATURDAY, WITH HIGHEST
CHANCES ACROSS NORTHERN PARTS OF THE AREA. THERE MAY BE ENOUGH
ELEVATED INSTABILITY TO ALLOW FOR A FEW RUMBLES OF THUNDER.
OTHERWISE, MUCH WARMER TEMPERATURES WILL SURGE INTO THE REGION,
HIGHS ON SATURDAY RISING INTO THE MID 70S TO LOW 80S OUTSIDE OF
THE POCONOS AND NEAR THE COAST, WHERE MID 60S ARE EXPECTED.
LOWS SATURDAY NIGHT LOOK TO GENERALLY BE IN THE 40S AND 50S, BUT
MAY REMAIN ABOVE 60 IN PARTS OF DELMARVA. THESE MILD
TEMPERATURES SATURDAY MAY CHALLENGE SOME RECORD HIGHS AS WELL
AS SOME RECORD WARMEST LOW TEMPERATURES. SEE CLIMATE SECTION
BELOW FOR MORE DETAILS.
THERE WILL LIKELY BE A RELATIVE LULL IN SHOWER CHANCES EARLY
SUNDAY WITH THE REGION IN THE WARM SECTOR AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE REGION BY SUNDAY AFTERNOON. HIGH
TEMPERATURES ON SUNDAY WILL BE HIGHLY DEPENDENT ON THE TIMING OF
THE FRONTAL PASSAGE WHICH REMAINS SOMEWHAT IN QUESTION, BUT
THERE SHOULD BE ENOUGH TIME FOR MOST OF NJ SOUTHWARD INTO
DELMARVA TO RISE INTO THE LOW-MID 70S. WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS ARE EXPECTED ALONG AND JUST AHEAD OF THE
COLD FRONT. AS OF RIGHT NOW, ANY SEVERE WEATHER THREAT LOOKS
QUITE LIMITED WITH THE PRIMARY LIMITING FACTOR BEING THE DEGREE
OF DESTABILIZATION, WITH MEAGER INSTABILITY AT BEST DEPICTED IN
MODEL GUIDANCE. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE GIVEN
RICH MOISTURE IN PLACE, AND PWATS AROUND 1.5", WHICH IS WELL
ABOVE THE 90TH PERCENTILE FOR THIS TIME OF YEAR. HOWEVER, GIVEN
THAT THIS IS EXPECTED TO BE A FAST MOVING SYSTEM, FLASH FLOODING
IS NOT CURRENTLY EXPECTED TO BE A CONCERN. TOTAL RAINFALL
AMOUNTS LOOK TO BE IN THE NEIGHBORHOOD OF 0.5", THOUGH LOCALLY
HIGHER AMOUNTS COULD OCCUR IN HEAVIER SHOWERS OR STORMS. BREEZY
CONDITIONS ARE LIKELY ON SUNDAY EVEN OUTSIDE OF ANY SHOWERS AND
STORMS WITH SOUTHWESTERLY WINDS GUSTING 25-35 MPH AHEAD OF THE
FRONT, WITH SIMILAR WESTERLY WINDS BEHIND IT.
IN THE WAKE OF THE COLD FRONT, TEMPERATURES ARE EXPECTED TO
RETURN TO NEAR OR EVEN SLIGHTLY BELOW NORMAL, WITH HIGHS MOSTLY
IN THE 50S AND LOWS IN THE 30S AND 40S THROUGH MID-WEEK. A SLOW
WARM UP MAY BEGIN THURSDAY AND BEYOND.
AVIATION /07Z FRIDAY THROUGH TUESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TONIGHT...CEILINGS CONTINUE TO LOWER TO NEAR OR AT LIFR
CONDITIONS. LIFR CEILINGS ARE EXPECTED AT ALL TERMINAL AROUND
10Z. MVFR TO IFR VSBYS IN DZ/BR FOR MOST OF THE NIGHT. VSBYS
WILL DROP TO LESS THAN 1SM BEFORE 12Z. E WINDS NEAR 10 KT,
BECOMING 5 KT OR LESS AFTER 09Z. MODERATE CONFIDENCE IN TIMING
OF CONDITIONS, BUT HIGH CONFIDENCE IN PREVAILING IFR AND
WORSENING CONDITIONS OVERNIGHT.
FRIDAY...LOW CIGS AND VSBYS FOR MUCH OF THE MORNING, WITH VSBYS
LESS THAN 1SM AND CIGS LESS THAN 500 FT. CONDITIONS IMPROVE BY
18Z, AND SHOULD BE VFR BY 21Z. S WINDS 5 TO 10 KT IN THE
MORNING, INCREASING TO 10 TO 15 KT WITH GUSTS UP TO 20 KT AFTER
18Z. MODERATE CONFIDENCE.
FRIDAY NIGHT...PRIMARILY VFR. A FEW SHOWERS DURING THE EVENING
COULD LEAD TO BRIEF SUB-VFR CONDITIONS.
OUTLOOK...
SATURDAY THROUGH SATURDAY NIGHT...MOSTLY VFR WITH SUB-VFR
CONDITIONS POSSIBLE AT TIMES IN SHOWERS AND PERHAPS A FEW
THUNDERSTORMS.
SUNDAY...SUB-VFR EXPECTED WITH A PERIOD OF SHOWERS AND STORMS.
GUSTY WINDS LIKELY THROUGH THE DAY SUNDAY.
SUNDAY NIGHT...CONDITIONS IMPROVE TO VFR AFTER THE EVENING
HOURS.
MONDAY THROUGH TUESDAY...PRIMARILY VFR. THERE IS A SLIGHT
CHANCE (AROUND 20%) FOR A FEW SHOWERS MONDAY NIGHT AND TUESDAY.
MARINE
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE OCEAN WATERS FROM
SANDY HOOK NJ TO GREAT EGG INLET, NJ UNTIL 6 AM TODAY. WINDS HAVE
DIMINISHED TO 10-15 KNOTS OUT OF THE EAST. HOWEVER, SEAS REMAIN
ELEVATED AT 5-7 FEET.
FOR TODAY, WINDS TURN OUT OF THE SOUTH AND THEN SOUTHWEST THIS
MORNING AT 5 TO 10 KT BEFORE INCREASING TO 15 TO 20 KT IN THE
AFTERNOON WITH GUSTS TO 25 KT. SEAS OF 2 TO 4 FT IN THE MORNING LOOK
TO BUILD TO 4-6 FEET AGAIN THIS AFTERNOON INTO TONIGHT. AFTER THIS
MORNING'S SMALL CRAFT ADVISORY EXPIRES, A NEW SMALL CRAFT ADVISORY
LOOKS TO BE NEEDED FOR THIS AFTERNOON INTO TONIGHT.
FOG HAS BEEN DEVELOPING EARLY THIS MORNING WITH VISIBILITY OF 1 TO 3
NM. VISIBILITY MAY DROP TO LESS THAN 1 NM. A MARINE DENSE FOG
ADVISORY WAS ISSUED FOR ALL ATLANTIC COASTAL WATERS AND DELAWARE BAY
THROUGH THIS AFTERNOON. VISIBILITY LOOKS TO IMPROVE THIS AFTERNOON.
ADDITIONAL FOG DEVELOPMENT MAY BE POSSIBLE TONIGHT.
OUTLOOK...
SATURDAY...NO MARINE HEADLINES CURRENTLY ANTICIPATED WITH WINDS
UNDER 25 KT AND SEAS UNDER 5 FEET.
SATURDAY NIGHT THROUGH SUNDAY...SCA CONDITIONS LIKELY WITH
GALES POSSIBLE. SOUTHERLY WINDS SATURDAY NIGHT WILL INCREASE TO
15-25 KT WITH GUSTS TO 30-35 KT. WINDS WILL BECOME SOUTHWESTERLY
ON SUNDAY. SEAS 4-8 FEET.
SUNDAY NIGHT THROUGH MONDAY...LINGERING SCA CONDITIONS LIKELY.
WINDS QUICKLY SUBSIDE TO BELOW 25 KT. SEAS REMAIN ELEVATED NEAR
5 FEET THROUGH MONDAY MORNING BEFORE DECREASING BELOW 5 FEET BY
MONDAY AFTERNOON.
MONDAY NIGHT THROUGH TUESDAY...MARINE CONDITIONS ARE EXPECTED TO
REMAIN BELOW SCA CRITERIA.
CLIMATE
A VERY WARM AIRMASS SATURDAY MAY CHALLENGE RECORD HIGH
TEMPERATURES AS WELL AS RECORD WARMEST LOW TEMPERATURES FOR
APRIL 4TH.
RECORD HIGH TEMPERATURES FOR APRIL 4TH:
SITE...................RECORD...YEAR(S)
AC AIRPORT (ACY).......78.......2017
PHILADELPHIA (PHL).....80.......1892
WILMINGTON (ILG).......80.......1950
ALLENTOWN (ABE)........79.......1928
TRENTON (TTN)..........82.......1892
READING (RDG)..........81.......1921
GEORGETOWN (GED).......81.......2023/2011/1963
MOUNT POCONO (MPO).....78.......1928
AC MARINA (55N)........77.......1999
RECORD WARMEST LOW TEMPERATURES FOR APRIL 4TH:
SITE...................RECORD...YEAR(S)
AC AIRPORT (ACY).......56.......1974
PHILADELPHIA (PHL).....60.......2025
WILMINGTON (ILG).......60.......2025
ALLENTOWN (ABE)........60.......1974
TRENTON (TTN)..........62.......1981
READING (RDG)..........58.......2025
GEORGETOWN (GED).......60.......2025/1950
MOUNT POCONO (MPO).....58.......1981
AC MARINA (55N)........56.......2025
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ430-
431.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
ANZ450>452.
DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ450.
DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ451>455.
DISCUSSION...GUZZO/MJL
AVIATION...GUZZO/MJL
MARINE...GUZZO/MJL
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