138
FXUS61 KPHI 230740
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
340 AM EDT WED APR 23 2025
SYNOPSIS
HIGH PRESSURE BUILDS DOWN OUT OF CANADA AND INTO THE MID-ATLANTIC
REGION THROUGH WEDNESDAY. THE HIGH THEN SHIFTS OFFSHORE WEDNESDAY
NIGHT INTO THURSDAY, WITH A WARM FRONT LIFTING NORTHWARD ACROSS
THE AREA FRIDAY NIGHT. A COLD FRONT WILL FOLLOW FOR FRIDAY NIGHT
INTO SATURDAY AS LOW PRESSURE LIFTS TO THE NORTHEAST OUT OF THE
OHIO VALLEY FRIDAY AND INTO NEW ENGLAND THROUGH SATURDAY. HIGH
PRESSURE RETURNS FOR SUNDAY INTO MONDAY.
NEAR TERM /THROUGH TONIGHT/
HIGH PRESSURE WILL SETTLE OVER THE AREA TODAY AND INTO TONIGHT
RESULTING IN A VERY NICE DAY. SKIES WILL BE MOSTLY SUNNY TO PARTLY
CLOUDY WITH HIGHS IN THE MID TO UPPER 70S. WITH WEAK FLOW DUE TO THE
HIGH IN PLACE, CONDITIONS ARE RIPE FOR THE DEVELOPMENT OF A SEA-
BREEZE AND BAY BREEZE. THIS COULD RESULT IN HIGHS NEAR THE COAST
BEING A FEW DEGREES COOLER IN THE 60S AND LOW 70S.
FOR TONIGHT, SKIES WILL BE MOSTLY CLEAR WITH CALM WINDS. THIS WILL
RESULT IN TEMPERATURES DROPPING A GOOD 25-30 DEGREES WITH FAVORABLE
RADIATIONAL COOLING CONDITIONS. LOWS WILL BE IN THE UPPER 40S TO LOW
50S.
SHORT TERM /THURSDAY THROUGH FRIDAY/
NO REAL CHANGES TO THE FORECAST THROUGH THE REST OF THE WEEK AS
HIGH PRESSURE WILL KEEP THE AREA UNDER DRY CONDITIONS WITH TEMPS
RUNNING A FEW DEGREES ABOVE NORMAL. ENSEMBLE MEANS AND ENSEMBLE
CLUSTER ANALYSIS SHOW NO APPRECIABLE DIFFERENCES THROUGH FRIDAY.
MAX TEMPS WILL WARM INTO THE UPPER 70S WITH LOWS THURSDAY IN THE
UPPER 40S TO LOW 50S.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
HIGH PRESSURE STARTS MOVING OFFSHORE FRIDAY NIGHT AS HIGHS
START FALLING ALOFT AND A WARM FRONT MOVES THROUGH AT THE
SURFACE. THE WARM FRONT WILL LEAD TO TEMPS STAYING IN THE 60S
OVERNIGHT FRIDAY NIGHT AND WILL LEAD TO AN INCREASE IN LOW LEVEL
MOISTURE WITH PWATS APPROACHING 1.5 INCHES. MID LEVEL PVA WILL
TRACK THE REGION AS CONSENSUS GUIDANCE BRINGS A POSITIVELY
TILTED TROUGH WITH SEVERAL IMPULSES. AT THE SURFACE THIS WILL
FEATURE A COLD FRONT THAT WILL BE THE SURFACE TRIGGER FOR
SHOWERS WITH SOME ISOLATED THUNDERSTORMS.
THE PRIMARY IMPACT OVER THE WEEKEND WILL BE ROUNDS OF MODERATE
TO HEAVY RAINFALL ON SATURDAY. TALL SKINNY CAPE PROFILES WITH
WARM CLOUD DEPTHS APPROACHING 10,000FT SUGGEST FAIRLY EFFICIENT
RAINFALL. NBM PROBS SUGGEST GENERALLY A 20% CHANCE OF GREATER
THAN 1" FOR MOST OF THE FORECAST AREA.
THE COLD FRONT PUSHES OFFSHORE SATURDAY NIGHT, BEFORE HIGH
PRESSURE BUILDS INTO THE MID ATLANTIC REGION SUNDAY INTO MONDAY,
BEFORE SHIFTING OFFSHORE MONDAY NIGHT AND OUT TO SEA TUESDAY.
DRY WEATHER WILL RETURN FOR SATURDAY NIGHT THROUGH TUESDAY, AND
AFTER A BRIEF PERIOD OF NEAR NORMAL TEMPERATURES SATURDAY NIGHT
INT SUNDAY, ABOVE NORMAL TEMPERATURES RETURN FOR SUNDAY NIGHT
THROUGH TUESDAY.
AVIATION /07Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...VFR WITH HIGH CLOUDS. LIGHT AND VARIABLE WINDS
FAVORING A NORTHERLY DIRECTION, 5 KT OR LESS. HIGH CONFIDENCE.
TODAY...VFR. NORTH TO NORTHEAST WINDS 5-10 KNOTS, BECOMING SOUTHWEST
OR SOUTH. A SEA/BAY BREEZE DEVELOPS AND SHOULD SHIFT THE WINDS TO
EAST AND SOUTHEAST AT KACY, KILG AND POSSIBLY MIV. LOW CONFIDENCE ON
WIND DIRECTION DETAILS/TIMING.
TONIGHT...VFR. WINDS LIGHT AND VARIABLE, POTENTIALLY FAVORING A
SOUTHERLY DIRECTION IF ANYTHING, 5 KT OR LESS. HIGH CONFIDENCE.
OUTLOOK...
THURSDAY-THURSDAY NIGHT...VFR.
FRIDAY...VFR WITH INCREASING CLOUD COVER.
FRIDAY NIGHT-SATURDAY NIGHT...SUB VFR CONDITIONS AS SHOWERS
IMPACT THE REGION WITH A SMALL CHANCE (10%-15%) OF
THUNDERSTORMS DURING THE DAY SATURDAY.
SATURDAY NIGHT-SUNDAY...VFR.
MARINE
SUB-SCA CONDITIONS EXPECTED THROUGH TONIGHT. WINDS LESS THAN 10 KT.
SEAS 2 TO 3 FEET.
OUTLOOK...
THURSDAY-FRIDAY...SUB SCA WITH SEAS 2-3 FEET AND WINDS LESS THAN
20KTS.
FRIDAY NIGHT-SUNDAY...SUB-SCA WINDS BUT SEAS WILL BUILD TO 4-5
FEET WITH SCA ANTICIPATED ON SATURDAY. SHOWERS EXPECTED ON
SATURDAY.
FIRE WEATHER
RELATIVE HUMIDITY VALUES WILL BE LOWER THAN YESTERDAY, AROUND 20-
25%, BUT WINDS WILL BE LIGHT AND UNDER 10 MPH. SEA/BAY BREEZES TODAY
SHOULD RESULT IN A RECOVERY OF THE RELATIVE HUMIDITY NEAR THE COAST
AND ALSO BRING A SWITCH IN WIND DIRECTION TO THE SOUTH/SOUTHEAST.
SIMILAR CONDITIONS EXPECTED ON THURSDAY, WITH RHS NEAR 25-35% AND
LIGHT WINDS.
RELATIVE HUMIDITY RECOVERS MORE THIS WEEKEND. GIVEN LIGHTER WINDS,
THERE ARE NO FIRE WEATHER CONCERNS EXPECTED REGARDING RAPID FIRE
SPREAD.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...GORSE
NEAR TERM...HOEFLICH
SHORT TERM...DEAL
LONG TERM...DEAL
AVIATION...DEAL/HOEFLICH
MARINE...DEAL/HOEFLICH
FIRE WEATHER...PHI
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