223
FXUS61 KPHI 050814
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
414 AM EDT SUN APR 5 2026
WHAT HAS CHANGED
SMALL CRAFT ADVISORIES EXTENDED INTO SUNDAY NIGHT FOR THE ATLANTIC
COASTAL WATERS.
KEY MESSAGES
1. FOG AND LOW STRATUS ERODES IN THE MORNING AS THE BACKDOOR FRONT
LIFTS NORTH AHEAD OF AN ADVANCING COLD FRONT THAT WILL BRING A ROUND
OF SHOWERS AND THUNDERSTORMS.
2. FIRE WEATHER CONDITIONS POSSIBLE ON MONDAY AND TUESDAY.
3. CHILLY TEMPERATURES WEDNESDAY MORNING AND THURSDAY MORNING MAY
AFFECT THE BEGINNING OF THE GROWING SEASON, WHERE THE GROWING SEASON
IS CURRENTLY ACTIVE.
DISCUSSION
KEY MESSAGE 1...FOG AND LOW STRATUS ERODES IN THE MORNING AS THE
BACKDOOR FRONT LIFTS NORTH AHEAD OF AN ADVANCING COLD FRONT THAT
WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS.
THE BACKDOOR FRONT FROM YESTERDAY WILL TREK NORTH ONCE MORE ACROSS
THE REGION THIS MORNING AS A WARM FRONT. THE FRONT IS EXPECT TO
SHIFT NORTH OF MUCH OF THE REGION, THOUGH WILL LIKELY GET HUNG UP IN
THE HIGHER ELEVATIONS, AROUND THE I-80 CORRIDOR. NORTH OF THE FRONT,
FOG AND LOW STRATUS WILL HANG ON. SOUTH OF THE FRONT, THE FOG WILL
MIX OUT AND THE STRATUS WILL LIFT, POSSIBLY SCATTER OUT FOR A BRIEF
PERIOD, ALLOWING SOME MODEST WARMING AHEAD OF THE ADVANCING COLD
FRONT FROM THE WEST. TEMPERATURES COULD WARM INTO THE MID 60S TO LOW
70S SOUTH OF THE FRONT BEFORE CLOUDS INCREASE AND SHOWERS AND
THUNDERSTORMS ARRIVE ALONG WITH THE COLD FRONT FROM THE WEST AROUND
MID MORNING THROUGH EARLY AFTERNOON. THIS WILL HINDER TYPICAL
DIURNAL HEATING FOR YET ANOTHER DAY. NORTH OF THE FRONT, TEMPERATURES
ARE EXPECTED TO ONLY WARM UP TO THE MID 50S TO LOW 60S.
THE LINE OF SHOWERS AND THUNDERSTORMS EXPECTED WITH THIS COLD FRONT
IS FORECAST TO DROP AROUND 0.5-0.75 INCHES OF RAIN ACROSS THE
REGION, WITH AREAS SOUTH AND EAST SEEING THE BEST CHANCES FOR
HEAVIER RAINFALL AND THUNDERSTORMS. THE SEVERE POTENTIAL IS RATHER
LIMITED WITH ONLY MARGINAL INSTABILITY (~300-700 J/KG MUCAPE)
DEVELOPING ACROSS THE SOUTHERN HALF OF THE REGION, MAINLY PHILLY
METRO AND SOUTH. THE EARLY TIMING THAT IS FORECASTED FOR THIS
FRONTAL PASSAGE IS ANOTHER FACTOR LIMITING THE SEVERE POTENTIAL
TODAY, BRINGING THE LINE OF SHOWERS AND CONVECTION ACROSS THE REGION
BEFORE DAYTIME HEATING CAN FULLY DESTABILIZE THE ATMOSPHERE. THE SPC
HAS A MARGINAL RISK FOR SEVERE WEATHER IN THIS REGION TODAY.
BEHIND THE COLD FRONT, TEMPERATURES WILL TAKE A MODEST FALL, WITH
OVERNIGHT LOWS EXPECTED TO DIP INTO THE MID 30S TO LOW 40S; AREAS
ACROSS THE POCONOS COULD REACH FREEZING. WNW WINDS WILL ALSO GUST TO
AROUND 15-20 MPH FOR A PERIOD OVERNIGHT.
KEY MESSAGE 2...A SLIGHT RISK OF FIRE SPREAD IS POSSIBLE ON MONDAY
AND TUESDAY.
A PERIOD OF FIRE WEATHER CONDITIONS IS POSSIBLE ON MONDAY, BUT MORE
SO ON TUESDAY AS A DRY AIRMASS INFILTRATES THE AREA. MINRH VALUES
WILL BE IN THE 30-40% RANGE ACROSS MUCH OF THE AREA FOR MONDAY
AFTERNOON WITH WESTERLY WINDS AROUND 10-15 MPH AND GUSTS UP TO 20-25
MPH. BY TUESDAY MORNING, A SECONDARY COLD FRONT IS FORECAST TO PASS
THROUGH THE REGION. THIS WILL CAUSE DEW POINTS TO FALL INTO THE
TEENS. MINRH VALUES WILL BE IN THE 25-35% RANGE WITH NORTHWEST WINDS
AROUND 15-20 MPH AND GUSTS UP TO 30-35 MPH.
AT THIS TIME, THESE CONDITIONS DO NOT MEET RED FLAG WARNING CRITERIA
ON MONDAY, BUT WILL BE CLOSE ON TUESDAY. DEPENDING ON HOW DRY FUEL
MOISTURE ARE ACROSS THE REGION, WE MAY NEED TO CONSIDER A SPECIAL
WEATHER STATEMENT FOR AN INCREASED RISK OF FIRE SPREAD. WE WILL BE
IN CONTACT WITH OUR PARTNERS AT A LATER TIME TO DETERMINE IF A SPS
IS WARRANTED.
KEY MESSAGE 3...CHILLY TEMPERATURES WEDNESDAY MORNING AND THURSDAY
MORNING MAY AFFECT THE BEGINNING OF THE GROWING SEASON, WHERE THE
GROWING SEASON IS CURRENTLY ACTIVE.
STRONG CANADIAN 1040 MB HIGH PRESSURE WILL SETTLE OVER NEW YORK
STATE ON WEDNESDAY MORNING BEFORE SHIFTING OFF THE NEW ENGLAND COAST
BY THURSDAY MORNING. IN WAKE OF A COLD FRONT ON TUESDAY, A
REINFORCING SHOT OF COLD, DRY AIR WILL ARRIVE TUESDAY NIGHT AND
LINGER INTO WEDNESDAY NIGHT. LOW TEMPERATURES WILL FALL INTO THE LOW
TO MID 20S TO LOW TO MID 30S FOR MOST LOCALES, WITH TEENS IN THE
POCONOS BY WEDNESDAY MORNING. CONSIDERING THAT THE GROWING SEASON IS
NOW ACTIVE ACROSS PORTIONS OF THE DELMARVA, PATCHY AREAS OF FROST
ARE POSSIBLE. HOWEVER, WITH SUCH A DRY AIRMASS IN PLACE, FROST
FORMATION MAY BE LIMITED.
TEMPERATURES WILL BE SOMEWHAT SIMILAR FOR THURSDAY MORNING, BUT WITH
THE HIGH SHIFTING OFFSHORE, LOWS SHOULD BE A FEW DEGREES WARMER THAN
WEDNESDAY. WITH CLOSER DEW POINT DEPRESSIONS EXPECTED FOR THURSDAY
MORNING, SUPPOSE MORE PATCHY FROST IS POSSIBLE. WILL CONTINUE TO
MONITOR FORECAST TRENDS AND EVALUATE IF ANY FROST HEADLINES MAY BE
WARRANTED IN THE COMING DAYS.
AVIATION /08Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TONIGHT...PREVAILING IFR/LIFR RESTRICTIONS ACROSS MOST
TERMINALS EARLY SUNDAY MORNING, BUT MIV/ACY WILL BE IN VFR/MVFR WITH
THE BACKDOOR FRONT RETREATING JUST NORTH OF THESE TERMINALS. THE
BACKDOOR FRONT WILL CONTINUE RETREATING NORTH AS A WARM FRONT EARLY
THIS MORNING, BUT LIKELY NOT REACH THE OTHER TERMINALS UNTIL AFTER
DAYBREAK. E WINDS AROUND 10 KTS WITH SSW WINDS SOUTH OF THE FRONT.
THERE IS ALSO A CONCERN FOR NON-CONVECTIVE LOW LEVEL WIND SHEAR
THROUGH 12Z. LOW CONFIDENCE.
SUNDAY...REMAINING IFR/LIFR CIGS WILL IMPROVE TO MVFR OR POSSIBLY
VFR IN THE MORNING. A LINE OF SHRA OR TSRA ASSOCIATED WITH A COLD
FRONT IS EXPECTED TO MOVE THROUGH THE REGION FROM W TO E, BRINGING
VIS AND CIG RESTRICTIONS ONCE AGAIN. TIMING OF THE FRONT HAS IT
ARRIVING AT KRDG AND KABE BETWEEN 13 AND 18Z, KPHL, KILG, KPNE, KTTN
BETWEEN 15 AND 20Z, AND KMIV AND KACY BETWEEN AROUND 17 AND 21Z.
ONCE THE LINE OF SHRA AND TSRA MOVES BY, CONDITIONS SHOULD RETURN TO
VFR QUICKLY. WINDS WILL START S OR SW AROUND 10 TO 15 KT, BUT WITH
THE LINE OF SHRA AND TSRA, EXPECT AN ABRUPT SHIFT TO W OR EVEN NW
WINDS AROUND 10G20KT. MODERATE CONFIDENCE.
SUNDAY NIGHT... EXCEPT FOR ANY LINGERING SHOWERS ACROSS SOUTHERN NJ
OR DELAWARE DURING SUNDAY EVENING, MOSTLY VFR IS EXPECTED. PATCHY
RURAL FOG POSSIBLE MONDAY MORNING. MODERATE CONFIDENCE.
OUTLOOK...
MONDAY THROUGH TUESDAY...VFR. GUSTY WINDS UP TO 20 KT POSSIBLE ON
MONDAY WITH GUSTY WINDS UP TO 25-30 KT POSSIBLE ON TUESDAY.
OTHERWISE, NO SIGNIFICANT WEATHER.
TUESDAY NIGHT THROUGH THURSDAY...VFR. NO SIGNIFICANT WEATHER
EXPECTED.
MARINE
SCA CONDITIONS THROUGH SUNDAY NIGHT. THE BACKDOOR FRONT WILL RETREAT
NORTH AS A WARM FRONT THIS MORNING, SHIFTING WINDS SW AND RAMPING UP
TO AROUND 20-25 KTS WITH SEAS BUILDING TO 4-8 FEET.
A COLD FRONT WILL PUSH THROUGH SUNDAY AFTERNOON, SHIFTING WINDS WNW
BEHIND IT. THERE MAY BE A LULL IN WINDS IMMEDIATELY BEHIND THE
FRONT, BUT WINDS OVERNIGHT WILL RAMP BACK UP TO 20-25 KTS. SEAS WILL
STAY ELEVATED AROUND 4-6 FEET.
OUTLOOK...
MONDAY THROUGH MONDAY NIGHT...NO MARINE HEADLINES EXPECTED. WINDS
GENERALLY 20 KT OR LESS AND SEAS OF 2-4 FEET.
TUESDAY...SMALL CRAFT ADVISORY CONDITIONS POSSIBLE WITH WINDS
GUSTING AROUND 25 KT.
TUESDAY NIGHT THROUGH THURSDAY...NO MARINE HEADLINES EXPECTED. WINDS
GENERALLY 20 KT OR LESS AND SEAS OF 2-4 FEET.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ430-
431.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ450>455.
DISCUSSION...DESILVA/MJL
AVIATION...DESILVA/MJL
MARINE...DESILVA/MJL
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