845
FXUS61 KPHI 240141
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
941 PM EDT WED APR 23 2025
SYNOPSIS
HIGH PRESSURE ACROSS THE AREA THIS EVENING WILL SHIFT OFFSHORE
OVERNIGHT 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 THURSDAY/
AS OF 935 PM, THE FORECAST REMAINS ON TRACK ACROSS THE AREA WITH
WIND TAPERING OFF, AND MOSTLY CLEAR SKIES ALLOWING FOR
RADIATIONAL COOLING AND A QUICK DROP OFF IN TEMPERATURES.
THOUGH SOME SHORTWAVE ENERGY MAY PROPAGATE THROUGH, THE REGION
WILL EXPERIENCE MAINLY ZONAL FLOW ALOFT DURING THE DURATION OF
THE NEAR TERM. WEAK HIGH PRESSURE LOOKS TO CONTROL THE REGION AT
THE SURFACE LEVEL DURING THE TERM. A WEAK/DIFFUSE WARM FRONT
WILL LIFT DURING THE LATE OVERNIGHT HOURS.
SKIES WILL REMAIN MOSTLY CLEAR TONIGHT WITH LIGHT AND VARIABLE
WINDS. LOWS WILL BE IN THE UPPER 40S TO LOW 50S. FOR THURSDAY,
MOSTLY CLEAR TO PARTLY CLOUDY SKIES WITH TEMPERATURES MAINLY IN
THE MID TO UPPER 70S FOR MOST INTERIOR LOCATIONS. HIGHER
ELEVATIONS AND AREAS NEAR THE COAST SHOULD EXPECT HIGHS IN THE
60S TO LOW 70S.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
HIGH PRESSURE WILL BE EAST OF THE AREA THURSDAY NIGHT AND EARLY
FRIDAY. WE'LL CONTINUE WITH THE FAIR WEATHER THOSE PERIODS, BUT
MOISTURE AND WARMTH WILL BE INCREASING OVER THE AREA FRIDAY AS THE
RETURN FLOW BEHIND THE HIGH SETS UP OVER OUR AREA. DEPENDING ON HOW
THE WINDS SET-UP THERE COULD BE SOME LOW CLOUDS CLOSE TO THE SHORE
FRI MORNING.
THE NEXT DISTURBANCE ARRIVES LATER FRIDAY AND WILL AFFECT THE
WEATHER INTO SATURDAY EVENING. AN UPPER TROUGH ACROSS THE GREAT
LAKES PROMOTES SURFACE CYCLOGENESIS ACROSS IN/OH AREA. THIS LOW THEN
DEEPENS AND MOVES ACROSS LAKE ERIE/ONTARIO AND ACROSS SOUTHERN
CANADA. AN ASSOCIATED COLD FRONT CROSSES THE AREA LATER SAT. WE'LL
BRING CHANCE POPS (30-50) ACROSS MOST AREAS FRI NIGHT AND LIKELY POPS
(70-80) FOR SATURDAY. THUNDERSTORMS ARE POSSIBLE TOO BUT SEVERE
WEATHER IS NOT. LOWS WILL REMAIN MILD FRI NIGHT/SAT MORNING WITH
MOSTLY 60S. HIGHS WILL BE A LITTLE ABOVE NORMAL SAT WITH LOW/MID 70S
S/E AND MID 60S N/W.
THE PREVIOUS SHIFT NOTED THAT 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.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
A COLD FRONT COMPLETES ITS TRANSIT ACROSS NJ AND DELMARVA SATURDAY
NIGHT WITH DECREASING POPS AFTER SAT EVENING. AS HIGH PRESSURE
ARRIVES FROM THE NORTHWEST SUNDAY, THE WEATHER WILL BE NICE FOR THE
LAST HALF OF THE WEEKEND AND INTO NEXT WEEK. AFTER THAT, LOW
PRESSURE WILL MOVE NORTH OF THE AREA BRINGING MILDER AIR AND A
CHANCE FOR SHOWERS/TSTMS LATER TUE AND INTO WED.
TEMPERATURES WILL START OUT THE PERIOD CLOSE TO NORMAL, BUT THEN THE
MILDER AIR GETS ADVECTED INTO THE REGION WITH WARMER TEMPS EACH DAY
INTO NEXT WEEK. BY THE MIDDLE OF HE WEEK, TEMPS WILL BE MUCH ABOVE
NORMAL WITH LOW/MID 80S IN MANY AREAS AND LOW 70S NEAR THE SHORE.
NORMAL HIGH TEMPERATURES FOR LATE APRIL ARE UPPER 60S TO LOW 70S FOR
PHILADELPHIA AREA AND LOW 60S FOR THE FAR NW AREAS. LOWS GENERALLY
ARE IN THE 40S, BUT CLOSER TO 50 NEAR THE HIGHLY URBAN AREAS.
AVIATION /02Z THURSDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. SOUTHWEST WIND AROUND 5 KT DECREASING TO LIGHT
AND VARIABLE BY 03Z. HIGH CONFIDENCE.
THURSDAY...VFR. LIGHT AND VARIABLE WIND BECOMING SOUTH-SOUTHWEST
AND INCREASING TO 5-10 KT DURING THE AFTERNOON. HIGH
CONFIDENCE.
OUTLOOK...
THURSDAY NIGHT/FRIDAY... VFR. INCREASING CLOUDS FRIDAY.
FRIDAY NIGHT... LOWERING CIGS WITH SHOWERS AND SUB-VFR POSSIBLE.
SAT/SAT EVENING...MVFR OR IFR PROBABLE WITH SHOWERS AND A CHANCE OF
TSTMS.
SUNDAY/MONDAY... VFR EXPECTED.
MARINE
SUB-SCA CONDITIONS EXPECTED THROUGH THURSDAY. WIND LESS THAN 15
KT. SEAS 2 FEET OR LESS.
OUTLOOK...
THURSDAY NIGHT/FRIDAY ... SUB-SCA EXPECTED. FAIR.
FRIDAY NIGHT THRU SAT. EVENING... SCA POSSIBLE ACROSS THE OCEAN WITH
SHOWERS AND A FEW TSTMS.
SAT NIGHT THRU MONDAY... SUB-SCA. FAIR.
FIRE WEATHER
RELATIVE HUMIDITY INCREASES THROUGH THE NIGHT WITH DIMINISHING
WIND AND DECREASING TEMPERATURES. THURSDAY WILL GENERALLY
FEATURE RH NEAR 25-35% AND FAIRLY 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...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR NJZ020-
022>027.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...OHARA
NEAR TERM...COOPER/HOEFLICH/WUNDERLIN
SHORT TERM...DEAL/OHARA
LONG TERM...OHARA
AVIATION...COOPER/OHARA/WUNDERLIN
MARINE...COOPER/OHARA/WUNDERLIN
FIRE WEATHER...PHI
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