452
FXUS61 KPHI 221829
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
229 PM EDT WED APR 22 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES TO THE FORECAST.
KEY MESSAGES
1. WEAK LOW PRESSURE MOVES THROUGH THE REGION THIS EVENING, FOLLOWED
BY HIGH PRESSURE THROUGH THURSDAY.
2. A WAVE OF LOW PRESSURE WILL BRING WIDESPREAD RAINFALL TO THE
REGION THIS WEEKEND WITH SEASONABLY COOL TEMPERATURES.
DISCUSSION
KEY MESSAGE 1...WEAK LOW PRESSURE MOVES THROUGH THE REGION THIS
EVENING, FOLLOWED BY HIGH PRESSURE THROUGH THURSDAY.
WEAK LOW PRESSURE PASSES THROUGH THE REGION EARLY THIS EVENING. ANY
SHOWERS OUT THERE WILL TAPER OFF LATE THIS AFTERNOON/EARLY THIS
EVENING, THEN THERE MAY BE ANOTHER BRIEF SHOT OF SHOWERS AFTER
SUNSET AS A SHORTWAVE MOVES THROUGH THE REGION. ANY QPF WILL BE
MINIMAL.
HIGH PRESSURE THEN BUILDS BOTH OVER HUDSON BAY IN CANADA AND OVER
THE MID-ATLANTIC AND SOUTHEAST. A LIGHT ONSHORE FLOW DEVELOPS
TONIGHT, AND WITH INCREASING LOW LEVEL MOISTURE, SOME PATCHY FOG
WILL DEVELOP.
WINDS TURN TO THE WEST-NORTHWEST ON THURSDAY AND WILL INCREASE TO 10
TO 15 MPH WITH GUSTS UP TO 20 MPH IN THE AFTERNOON. SKIES WILL BE
SUNNY, AND IT WILL BE QUITE WARM WITH HIGHS IN THE MID TO UPPER 70S,
THOUGH SOME SPOTS ALONG THE I-95 CORRIDOR AND INTERIOR PORTIONS OF
DELMARVA MAY TOP OFF AROUND 80.
SURFACE DEW POINTS WILL START OUT IN THE UPPER 40S, THEN WILL MIX
DOWN TO THE LOW 40S WITH EFFICIENT MIXING. THIS RESULTS IN MINRH
VALUES FROM 30 TO 35 PERCENT AWAY FROM THE COASTS.
KEY MESSAGE 2...A WAVE OF LOW PRESSURE WILL BRING WIDESPREAD
RAINFALL TO THE REGION THIS WEEKEND WITH SEASONABLY COOL
TEMPERATURES.
A BACK DOOR COLD FRONT WILL SINK SOUTH THROUGH THE REGION ON FRIDAY
AS HIGH PRESSURE SETTLES NEAR NEW ENGLAND. A FEW SHOWERS MAY DEVELOP
IN THE AFTERNOON AS SOME ENERGY EMBEDDED IN THE NORTHWEST FLOW ALOFT
CLIPS THE REGION, BUT OVERALL CONDITIONS LOOK TO BE MAINLY DRY AND
COOL. FORECAST HIGHS ON FRIDAY WILL MAINLY BE IN THE 60S TO AROUND
70, PERHAPS PUSHING INTO THE MID 70S NEAR THE EASTERN SHORE OF MD.
IT SHOULD BE NOTED THAT FORECAST GUIDANCE NOTORIOUSLY STRUGGLES WITH
BACK DOOR FRONTS AND IT IS ENTIRELY POSSIBLE THAT THE FRONT SINKS
THROUGH MUCH FASTER THAN CURRENTLY PROGGED. THIS WOULD RESULT IN
MUCH COOLER TEMPERATURES THAN WHAT IS CURRENTLY IN THE FORECAST.
LOW PRESSURE WILL THEN BEGIN TO ORGANIZE OVER THE GREAT LAKES REGION
BY FRIDAY NIGHT AND PUSH TOWARD THE NORTHEAST AND MID-ATLANTIC
REGION OVER THE WEEKEND. AS OF NOW, THERE ARE STILL SOME TIMING
DIFFERENCES ON HOW QUICKLY THE LOW TRACKS THROUGH THE MID-ATLANTIC.
SOME GUIDANCE INDICATES A QUICK MOVING LOW THAT WILL BE OFF THE
COAST BY SUNDAY, WHEREAS SOME DEPICT A SLOWER MOVING LOW THAT WON'T
MOVE OFF THE COAST UNTIL SUNDAY NIGHT. FOR THIS REASON, HAVE CARRIED
AT LEAST A CHANCE OF POPS THROUGH THE ENTIRE WEEKEND, WITH THE MOST
LIKELY TIMING OF PRECIP BEING SATURDAY AFTERNOON AND EVENING. WHILE
NOT EXPECTING A WASHOUT BOTH DAYS, SHOWERS WILL LIKELY BE AROUND AT
TIMES. CURRENT RAINFALL AMOUNTS LOOK TO TOTAL AROUND 0.5-1.0 INCHES
TO THE NORTH OF PHILADELPHIA AND AROUND 0.1-0.5 INCHES TO THE SOUTH
OF PHILADELPHIA.
SATURDAY WILL BE DREARY, DAMP, AND RAW WITH HIGHS ONLY IN THE UPPER
40S TO UPPER 50S. SOME IMPROVEMENT SHOULD BE EXPECTED BY SUNDAY
(THOUGH IS DEPENDENT ON LOW TIMING MENTIONED ABOVE), WITH TEMPS
INCREASING INTO THE MID 50S TO MID 60S. BY EARLY NEXT WEEK, DRY AND
WARMER CONDITIONS RETURN WITH HIGHS RETURNING BACK TO NORMAL.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY...OVERALL, VFR. CANNOT RULE OUT SOME BRIEF MVFR CIGS
INTO THIS EVENING, BUT CONFIDENCE LOW IN THAT OCCURRING. FOR NOW,
WILL INCLUDE AT KABE/KTTN. VARIABLE WINDS AROUND 5 KT.
TONIGHT...VFR INITIALLY, THEN AT LEAST MVFR CONDS IN PATCHY FOG AND
LOW STRATUS FOR MOST TERMINALS. E WINDS LESS THAN 5 KT, THOUGH
MOSTLY LGT/VRB. LOW CONFIDENCE.
THURSDAY...MORNING FOG AND STRATUS WILL LIFT AND DISSIPATE SHORTLY
AFTER SUNRISE, THEN VFR. NW WINDS 5 TO 10 KT, INCREASE TO 10 TO 15
KT WITH GUSTS UP TO 20 KT IN THE AFTERNOON. MODERATE CONFIDENCE.
OUTLOOK...
THURSDAY NIGHT THROUGH FRIDAY NIGHT...PRIMARILY VFR EXPECTED
WITH A CHANCE OF RAIN SHOWERS ON FRIDAY NIGHT.
SATURDAY THROUGH SUNDAY...SUB-VFR CONDITIONS LIKELY. RAIN SHOWERS
LIKELY, ESPECIALLY SATURDAY AFTERNOON INTO SATURDAY NIGHT. PATCHY
FOG POSSIBLE.
SUNDAY NIGHT THROUGH MONDAY...VFR EXPECTED. A SLIGHT CHANCE OF RAIN
SHOWERS.
MARINE
SUB-SMALL CRAFT ADVISORY CONDITIONS TONIGHT THROUGH THURSDAY. SOUTH
WINDS 10 TO 15 KT WITH GUSTS UP TO 20 KT BECOME NE 5 TO 10 KT
TONIGHT, THEN NW 10 TO 15 KT THURSDAY MORNING. WINDS THEN BECOME S
IN THE AFTERNOON BEHIND AFTERNOON SEA BREEZES. SEAS OVERALL 2 TO 4
FEET.
VSBY RESTRICTIONS POSSIBLE IN FOG, MOSTLY NEAR THE COASTS, LATE
TONIGHT THROUGH THURSDAY MORNING.
OUTLOOK...
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NO MARINE HEADLINES EXPECTED.
WINDS AROUND 5-15 KT WITH SEAS OF 2-3 FEET.
SATURDAY THROUGH SUNDAY NIGHT...SCA CONDITIONS LIKELY TO DEVELOP BY
SATURDAY AFTERNOON. WINDS AROUND 15-25 KT WITH GUSTS UP TO 30 KT
POSSIBLE. SEAS OF 4-7 FEET. RAIN SHOWERS LIKELY.
MONDAY...LINGERING SCA CONDITIONS POSSIBLE. WINDS GENERALLY AROUND
15-20 KT WITH SEAS OF 3-5 FEET.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
DISCUSSION...DESILVA/MPS/RCM
AVIATION...DESILVA/MPS
MARINE...DESILVA/MPS
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