959
FXUS61 KPHI 220703
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
303 AM EDT SUN MAR 22 2026
WHAT HAS CHANGED
SMALL CRAFT ADVISORY ISSUED.
KEY MESSAGES
1. SHOWERS AND POTENTIALLY SOME SEVERE THUNDERSTORMS,
LATER TODAY INTO THIS EVENING, THEN TURNING MUCH COOLER WITH GUSTY
WINDS ON MONDAY.
2. FAIR AND SEASONABLE FOR THE MIDDLE OF THIS COMING WEEK.
DISCUSSION
KEY MESSAGE 1...SHOWERS AND POTENTIALLY SOME SEVERE THUNDERSTORMS,
LATER TODAY INTO THIS EVENING, THEN TURNING MUCH COOLER WITH GUSTY
WINDS ON MONDAY.
AN UPPER-LEVEL TROUGH ACROSS CENTRAL CANADA IS FORECAST TO AMPLIFY
SOME TODAY INTO MONDAY ON ITS SOUTH SIDE FROM THE GREAT LAKES AND
NORTHEAST. THIS WILL DRIVE SURFACE LOW PRESSURE EASTWARD FROM THE
GREAT LAKES WHICH TRACKS NEAR OUR AREA LATER TODAY. HOWEVER, ANOTHER
WEAK LOW DEVELOPS ALONG THE FRONT AND WITHIN THE ELONGATED PRESSURE
TROUGH. THIS SECONDARY WEAK LOW MAY BECOME CONVECTIVELY ENHANCED AS
IT SLIDES EAST-SOUTHEAST ALONG THE FRONT LATE THIS AFTERNOON INTO
TONIGHT. A FRONTAL ZONE WILL BE TO OUR NORTH AND THIS WILL KEEP OUR
AREA WITHIN THE WARM SECTOR WITH SOUTHWESTERLY WINDS DURING MOST OF
THE DAY TODAY. HOWEVER, A STRONG COLD FRONT WILL MOVE SOUTHEASTWARD
ACROSS THE AREA TONIGHT BRINGING COLDER AIR ACROSS OUR AREA MONDAY
THROUGH TUESDAY. AHEAD OF THE FRONT, HIGH TEMPERATURES TODAY ARE
FORECAST TO REACH THE 60S TO LOW/MID 70S FOR MOST OF THE REGION. A
MORE SOUTHERLY WIND COMPONENT THOUGH WILL KEEP IT COOLER ALONG THE
COAST DUE TO THE WIND OFF THE COLD OCEAN.
A RIBBON OF STRONGER FORCING FOR ASCENT AHEAD OF AND WITH THE COLD
FRONT AND WEAK SURFACE LOW RESULTS IN AN AREA OF SHOWERS AND STORMS
ARRIVING IN OUR NORTHWEST ZONES AROUND MID TO LATE THIS AFTERNOON
THEN SPREADING SOUTHEASTWARD THROUGH THIS EVENING. THE MODEL
FORECAST SOUNDINGS INDICATE INSTABILITY DEVELOPING WITHIN THE WARM
SECTOR, ESPECIALLY WEST OF OUR AREA HEADING INTO CENTRAL PA. IT'S
THERE WHERE STORMS ARE LIKELY TO INITIALLY FIRE THIS AFTERNOON WITH
A GOOD CHANCE OF AT LEAST SOME BEING SEVERE AS LAPSE RATES ARE STEEP
THROUGH THE LOW AND MID LEVELS AND THE SHEAR AND WIND FIELDS ARE
VERY STRONG. THESE SHOWERS/STORMS SHOULD THEN MOVE EAST AND
SOUTHEASTWARD INTO THE AREA THROUGH THE LATE AFTERNOON AND EVENING,
LIKELY AS A LINE OR ONE OR MORE LINE SEGMENTS. THE FORECAST GETS A
BIT TRICKIER FOR OUR CWA IN TERMS OF STORM INTENSITY AS THERE WILL
BE LESS INSTABILITY TO WORK WITH...ESPECIALLY SURFACE BASED
INSTABILITY AS THE LOW LEVELS STABILIZES SOME INTO THIS EVENING.
THAT SAID, IT SHOULD TAKE SOME TIME FOR STORMS TO WEAKEN SO IT'S
LIKELY THERE WILL BE AT LEAST SOME SCATTERED INSTANCES OF SEVERE
WEATHER IN OUR EASTERN PA ZONES WHERE THE STORM PREDICTION CENTER
HAS OUTLINED IN A SLIGHT RISK FOR SEVERE STORMS. ELSEWHERE, ACROSS
MOST OF DELMARVA AND NJ THE THREAT LEVEL FROM SPC REMAINS MARGINAL
AS STORMS SHOULD BE WEAKER BY THE THE TIME THEY GET HERE. THIS MEANS
ANY INSTANCES OF SEVERE WEATHER SHOULD BE ISOLATED. IN TERMS OF
HAZARDS, THE STEEP LAPSE RATES THROUGH THE MID LEVELS ALONG WITH THE
STRONG DEEP LAYER SHEAR INDICATE SEVERE HAIL WILL BE A POTENTIAL
HAZARD. BUT WITH THE STRONG WIND FIELD DAMAGING WINDS WILL CERTAINLY
BE ON THE TABLE AS WELL IN TERMS OF THREATS. THE TORNADO RISK LOOKS
RATHER LOW AS OF NOW UNLESS THE LOW-LEVEL MOISTURE (SURFACE DEW
POINTS) ENDS UP INCREASING MORE THAN CURRENTLY FORECAST.
WHILE STILL SOME UNCERTAINTY WITH THE OVERALL TIMING, THE MAIN
SEVERE THUNDERSTORM THREAT STILL LOOKS TO BE BETWEEN 4 PM AND 10 PM.
THE PRECIPITABLE WATER IS FORECAST TO INCREASE TO 1+ INCHES AS WE
GET INTO THIS EVENING. THIS ALONG WITH SOME POTENTIAL FOR A TIME OF
TRAINING CONVECTION COULD RESULT IN SOME CORRIDORS OF HEAVIER
RAINFALL (1+ INCHES). IF HEAVY RAINFALL RATES OCCUR OVER THE MORE
URBAN AREAS, LOCALIZED FLASH FLOODING IS POSSIBLE. OTHERWISE, THE
RAINFALL IS MUCH NEEDED. ONCE THE FRONT STARTS TO PUSH SOUTH OF THE
AREA OVERNIGHT THIS ISN'T A SITUATION WHERE THE PRECIPITATION WILL
QUICKLY COME TO AN END. THIS REASON FOR THIS IS THAT WITH THE NEW
LOW DEVELOPING ALONG THE FRONT NEAR THE AREA, ADDITIONAL RAINFALL IS
LIKELY NORTH OF THE BOUNDARY ACROSS OUR AREA WITH THE PRECIP
BECOMING MORE STRATIFORM IN NATURE. THE SEVERE WEATHER THREAT WILL
BE OVER BY THIS POINT BUT RAIN, POTENTIALLY MODERATE AT TIMES, WILL
CONTINUE FOR SEVERAL MORE HOURS.
FOR MONDAY, THE COLD ADVECTION PATTERN BEHIND THE FRONT WILL RESULT
IN HIGHS FOR THE DAY LIKELY OCCURING IN THE PREDAWN HOURS WITH
TEMPERATURES THEN DROPPING EARLY BEFORE HOLDING FAIRLY STEADY AT
GENERALLY IN THE UPPER 40S TO LOW 50S FOR MOST OF THE DAY. RAIN
SHOULD TAPER OFF WEST TO EAST AROUND OR SHORTLY AFTER SUNRISE FOR
MOST AREAS AND IT'S WORTH NOTING IT COULD END AS A LITTLE WET SNOW
OR A WINTRY MIX ACROSS THE HIGHER ELEVATIONS OF THE POCONOS. LITTLE
TO NO ACCUMULATION IS EXPECTED THOUGH. ALSO FOR MONDAY, THE PRESSURE
GRADIENT TIGHTENS IN THE WAKE OF THE DEPARTING LOW TO OUR EAST AND
NORTHEAST AS HIGH PRESSURE BUILDS TOWARD THE GREAT LAKES. THIS
COMBINED WITH STRONGER COLD AIR ADVECTION WILL STEEPEN THE LOW-LEVEL
LAPSE RATES AND RESULT IN DEEPER MIXING. SO EXPECT A GUSTY NORTHWEST
WIND RESULTING DURING MONDAY ESPECIALLY IN THE AFTERNOON INTO THE
EVENING, WITH PEAK WIND GUSTS OF 25-35 MPH.
KEY MESSAGE 2...FAIR AND SEASONABLE FOR THE MIDDLE OF THIS COMING
WEEK.
HIGH PRESSURE BUILDS IN TUESDAY AND DOMINATES OUR WEATHER THROUGH
WEDNESDAY BRINGING TRANQUIL CONDITIONS. TUESDAY SHOULD BE MAINLY
SUNNY WITH MORE IN THE WAY OF CLOUD COVER FOR WEDNESDAY AS THE HIGH
STARTS TO WEAKEN AND A WARM FRONT APPROACHES. AS A RESULT, TUESDAY
WILL REMAIN ON THE COOLER SIDE OF AVERAGE WITH HIGHS MAINLY IN THE
UPPER 40S TO LOW 50S. TEMPERATURES THEN MODERATE SOME FOR WEDNESDAY
WITH THE APPROACH OF THE WARM FRONT WITH HIGHS FOR MOST AREAS
GENERALLY IN THE MIDDLE TO UPPER 50S.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...CONDITIONS ARE EXPECTED TO BE VFR AT RDG AND ABE.
THERE IS A LOW (AROUND 20%) CHANCE FOR A FEW SHOWERS OR SOME
BR, BUT HAVE NOT INCLUDED IN THE TAFS AT THIS TIME. THE I-95
TERMINALS ARE EXPECTED TO BE VFR FOR MUCH OF THE NIGHT, BUT A
PERIOD OF MVFR CEILINGS ARE LIKELY BEGINNING 10-11Z. SOME PATCHY
FOG CANNOT BE RULED OUT, BUT ALSO LEFT OUT OF THE TAFS FOR NOW.
FOR MIV AND ACY, THERE IS A HIGHER LIKELIHOOD OF RESTRICTIONS,
WITH MVFR CEILINGS DEVELOPING AROUND 09-10Z. FOG DEVELOPMENT IS
POSSIBLE IN THIS TIMEFRAME AS WELL, WHICH COULD LEAD TO IFR
CONDITIONS AT TIMES. WINDS FAVORING A SOUTHERLY DIRECTION AROUND
5 KT OR LESS. LOW CONFIDENCE OVERALL REGARDING THE DEVELOPMENT
AND EXTENT OF ANY FOG, AS WELL AS THE INLAND EXTENT OF LOW
CEILINGS.
TODAY...MVFR CEILINGS TO START FOR MIV, ACY, AND THE I-95
TERMINALS, WITH BRIEF PERIODS OF IFR POSSIBLE IN FOG PRIMARILY
AT MIV AND ACY THROUGH AROUND 14Z. CONDITIONS THEN LOOK TO
IMPROVE TO VFR FOR MUCH OF THE DAY. SHOWERS AND A FEW STORMS,
PERHAPS STRONG, MAY BEGIN TO IMPACT RDG AND ABE AS EARLY AS
20-22Z, BUT WILL LIKELY HOLD OFF THROUGH 00Z FOR ALL OTHER
TERMINALS. SOUTHWESTERLY WINDS GENERALLY 5-10 KT. MODERATE
CONFIDENCE.
TONIGHT...MVFR CEILINGS AT ALL TERMINALS. SHOWERS AND A FEW
STORMS, SOME PERHAPS STRONG, MAY MOVE THROUGH THE TERMINALS
THROUGH 03-05Z. THEREAFTER, LINGERING SHOWERS ARE EXPECTED
THROUGH MOST OF THE NIGHT. WINDS BECOMING NORTHERLY AT 5-10 KT
WITH THE PASSAGE OF A COLD FRONT BETWEEN 03-06Z. MODERATE
CONFIDENCE.
OUTLOOK...
MONDAY..IMPROVING CONDITIONS, LIKELY TO VFR. NORTHWEST WIND
GUSTS 20-30 KT ON MONDAY.
MONDAY NIGHT THROUGH WEDNESDAY...VFR. NO SIGNIFICANT WEATHER.
WEDNESDAY NIGHT THROUGH THURSDAY...PERIODS OF SUB-VFR
CONDITIONS POSSIBLE WITH A CHANCE OF SHOWERS.
MARINE
CONDITIONS OVER THE WATERS ARE EXPECTED TO STAY BELOW SMALL
CRAFT ADVISORY LEVELS THROUGH THIS AFTERNOON. HOWEVER SEAS START
TO COME UP INTO THIS EVENING AND FOR THIS REASON A SMALL CRAFT
ADVISORY IS IN EFFECT FOR OUR NJ COASTAL WATERS ZONES BEGINNING
AT 6 PM.
BY MONDAY MORNING, EXPECT NORTHERLY WINDS INCREASING TO
15 TO 20 GUSTING TO AROUND 25 KNOTS FOR ALL ZONES SO THE SMALL
CRAFT ADVISORY IS EXPANDED TO INCLUDE ALL WATERS BEGINNING 8 AM
MONDAY. THESE CONDITIONS SHOULD PERSIST THROUGH MONDAY BEFORE
DIMINISHING LATER MONDAY NIGHT. ALSO EXPECT SOME RAIN/SHOWERS
AND POTENTIALLY A FEW STORMS OVER THE WATERS SUNDAY NIGHT.
OUTLOOK...
TUESDAY AND WEDNESDAY...THE CONDITIONS ARE ANTICIPATED TO BE BELOW
SMALL CRAFT ADVISORY CRITERIA.
THURSDAY...SMALL CRAFT ADVISORY CONDITIONS MAY DEVELOP, MAINLY AT
NIGHT.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 3 AM EDT TUESDAY FOR
ANZ430-431.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT
TUESDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ454-455.
DISCUSSION...DESILVA/FITZSIMMONS/GORSE
AVIATION...COOPER
MARINE...DESILVA/FITZSIMMONS/GORSE
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