229
FXUS61 KPHI 102344
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
744 PM EDT TUE MAR 10 2026
WHAT HAS CHANGED
THE RISK FOR SOME STRONG TO SEVERE THUNDERSTORMS HAS INCREASED
SOME WEDNESDAY NIGHT.
KEY MESSAGES
1. AREAS OF PATCHY DENSE FOG POSSIBLE AGAIN TONIGHT, MAINLY
ALONG THE COAST. WARMTH AND INCREASINGLY MORE HUMID CONDITIONS
WEDNESDAY WITH RECORD HIGH TEMPERATURES POSSIBLE.
2. A STRONG COLD FRONT CROSSES OUR REGION LATE WEDNESDAY NIGHT
AND THURSDAY MORNING WITH SHOWERS AND SOME POTENTIALLY STRONG TO
SEVERE THUNDERSTORMS.
3. LINGERING SHOWERS WILL BE POSSIBLE IN THE WAKE OF THE COLD
FRONT THURSDAY MORNING.
4. ANOTHER ROUND OF WIDESPREAD PRECIPITATION IS LIKELY SUNDAY
NIGHT INTO MONDAY NIGHT AS A STRONG COLD FRONT APPROACHES THE
REGION.
DISCUSSION
KEY MESSAGE 1...AREAS OF PATCHY DENSE FOG POSSIBLE AGAIN
TONIGHT, MAINLY ALONG THE COAST. WARMTH AND INCREASINGLY MORE
HUMID CONDITIONS WEDNESDAY WITH RECORD HIGH TEMPERATURES
POSSIBLE.
ANOTHER ROUND OF FOG AND MIST IS POSSIBLE AGAIN THIS EVENING
INTO EARLY WEDNESDAY MORNING, BUT CONFIDENCE IN OCCURRENCE IS
LOW. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THIS SLUG OF
MARINE FOG WILL LIKELY REMAIN MOSTLY OVER THE WATERS OR RIGHT
ALONG THE COASTAL STRIP.
SOUTHERLY FLOW INCREASES ON WEDNESDAY AS A STRONG COLD FRONT
APPROACHES FROM THE WEST AND THE PRESSURE GRADIENT TIGHTENS.
SOUTH TO SOUTHWEST WINDS WILL INCREASE WITH GUSTS 20-25 MPH.
WARM AIR WILL REMAIN IN PLACE, AND A MORE HUMID AIRMASS SPREADS
INTO THE REGION WITH DEW POINTS RISING INTO THE UPPER 50S TO LOW
60S. HIGH TEMPERATURES ARE FORECAST TO BE IN THE MID TO UPPER
70S FOR MANY PLACES, ALTHOUGH STILL MUCH COOLER ALONG THE COAST
DUE TO A SOUTHERLY WIND OFF THE COLD OCEAN. SEE THE CLIMATE
SECTION BELOW FOR THE RECORDS. THE WARMTH COULD BE MUTED SOME
HOWEVER IF THICKER CLOUD COVER ARRIVES FASTER DURING THE DAY
WEDNESDAY. SOME SHOWERS SHOULD START TO DEVELOP DURING THE
COURSE OF THE DAY, ESPECIALLY LATER IN THE AFTERNOON ACROSS OUR
WESTERN ZONES.
KEY MESSAGE 2...A STRONG COLD FRONT CROSSES OUR REGION LATE
WEDNESDAY NIGHT AND THURSDAY MORNING WITH SHOWERS AND SOME
POTENTIALLY STRONG TO SEVERE THUNDERSTORMS.
LOW PRESSURE WILL TRACK TO OUR NORTH WEDNESDAY AND WEDNESDAY
NIGHT. THIS PULLS A STRONG COLD FRONT ACROSS OUR REGION LATE
WEDNESDAY NIGHT AND THURSDAY MORNING. SHOWERS DEVELOP WITH THE
ARRIVAL AND PASSAGE OF THE FRONT. A WARM AND MOIST ENVIRONMENT
WILL BE IN PLACE AHEAD OF THE COLD FRONT AND SOME THUNDER WILL
BE POSSIBLE WITH THE FRONT OR WITH A PRE-FRONTAL ZONE OF
FORCING. AHEAD OF THE UPPER- LEVEL TROUGH, VERY STRONG DEEP-
LAYER SOUTHWESTERLY FLOW IS FORECAST WITH AROUND 80 KNOTS AT 500
MB AND 50-60 KNOTS AT 850 MB. THIS WILL RESULT IN STRONG SHEAR
PROFILES THAT WOULD FAVOR LINE SEGMENTS WITH LOCALLY STRONG TO
DAMAGING WIND GUSTS, WITH A LOWER POTENTIAL FOR SOME QUARTER
SIZE HAIL OR AN ISOLATED TORNADO. OVERALL, THE GREATER RISK FOR
SEVERE THUNDERSTORMS LOOKS TO BE JUST TO OUR WEST WHERE STRONGER
FORCING COINCIDES WITH GREATER INSTABILITY WITH STRONG SHEAR
EARLIER IN THE DAY. HOWEVER, THE LATEST TREND IN GUIDANCE
POTENTIALLY SHOWS A SLIGHTLY EARLIER ARRIVAL TIME IN THE LATE
AFTERNOON TO EARLY EVENING. THIS EARLIER TIME WOULD POTENTIALLY
RESULT IN A HIGHER RISK FOR SEVERE STORMS WITH GREATER
INSTABILITY REMAINING ACROSS OUR REGION. SPC HAS EXPANDED THE
SLIGHT RISK TO INCLUDE MOST OF THE WESTERN AND SOUTHERN PORTIONS
OF THE AREA AS A RESULT.
KEY MESSAGE 3...LINGERING SHOWERS WILL BE POSSIBLE IN THE WAKE
OF THE COLD FRONT THURSDAY MORNING.
THE COLD FRONT CLEARS OUR REGION THURSDAY MORNING, THEN STRONG
COLD AIR ADVECTION DEVELOPS THROUGHOUT THE DAY. DRY AIR
ADVECTION IS ALSO EXPECTED IN THE WAKE OF THE FRONT, BUT THERE
SHOULD BE A SMALL WINDOW OF OPPORTUNITY BETWEEN THE COLD FRONT
PASSAGE AND THE DRIEST AIR ARRIVING FOR LINGERING SHOWERS TO
CONTINUE. IN FACT FOR SOME AREAS, THIS WILL BE THE HIGHEST
CHANCES. BY THIS POINT HOWEVER, A STRONG LOW LEVEL INVERSION
WILL BE DEVELOPING, LIMITING INSTABILITY. THUS, EXPECT THE MODE
OF PRECIPITATION THROUGH THIS PERIOD TO BE RAIN SHOWERS AS THE
RISK FOR ANY THUNDERSTORMS APPEARS VERY LOW.
DAILY HIGH TEMPERATURES ARE LIKELY TO OCCUR JUST AFTER
MIDNIGHT, THEN TEMPERATURES THURSDAY FALL INTO AND THROUGH THE
50S IN THE MORNING TO THE 40S BY LATE AFTERNOON AS STRONG
NORTHWEST WINDS DEVELOP BEHIND THE FRONT.
KEY MESSAGE 4...ANOTHER ROUND OF WIDESPREAD PRECIPITATION IS
LIKELY SUNDAY NIGHT INTO MONDAY NIGHT AS A STRONG COLD FRONT
APPROACHES THE REGION.
A LOW PRESSURE SYSTEM, TAKING A SIMILAR TRACK TO THE WEDENSDAY
SYSTEM, WILL BRING A STRONG COLD FRONT TO OUR REGION EARLY NEXT
WEEK. WIDESPREAD PRECIPITATION IS LIKELY AHEAD OF AND JUST
BEHIND THE FRONT. FOR NOW, FORECAST FAVORS A MOSTLY RAIN EVENT.
ANY POTENTIAL FOR WINTRY PRECIPITATION WILL BE HIGHLY DEPENDENT
ON THE TIMING OF BOTH THE PRECIPITATION AND THE FRONT. AT THIS
RANGE, THOSE DETAILS ARE HIGHLY UNCERTAIN.
MODELS SHOW VERY STRONG COLD AIR ADVECTION IN THE WAKE OF THIS
COLD FRONT. THUS, BY TUESDAY, WIDESPREAD HIGH TEMPERATURES IN
THE 20S AND 30S ARE POSSIBLE.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...PREVAILING VFR EXPECTED FOR MOST TERMINALS. THE
EXCEPTION IS NEAR KACY WHERE ANOTHER ROUND OF MARINE FOG, MIST,
AND STRATUS IS POSSIBLE, THOUGH PROBABILITY IS ONLY AROUND 20%,
THUS THE CHANCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF AT
THIS TIME. WINDS GENERALLY OUT OF THE SOUTH AROUND 5 KT OR LESS.
MODERATE CONFIDENCE.
WEDNESDAY...MAINLY VFR WITH INCREASING CLOUDS DURING THE DAY.
CHANCE (30-50%) FOR SHOWERS OR A THUNDERSTORM IN THE AFTERNOON.
HIGHEST CHANCES FOR THE LEHIGH VALLEY AND I-95 TERMINALS DURING
THE DAYTIME, WITH THE THREAT PEAKING BETWEEN 20Z-02Z.
SHOWERS/THUNDERSTORMS SHOULD HOLD OFF AROUND KACY/MIV UNTIL
AFTER 00Z. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS COULD
RESULT IN BRIEF IFR CONDITIONS. SOUTH-SOUTHWEST WINDS AROUND 10
KNOTS WITH GUSTS UP TO 20 KNOTS. MODERATE CONFIDENCE.
WEDNESDAY NIGHT...SUB-VFR CONDITIONS POSSIBLE (40-60% CHANCE)
WITH AREAS OF SHOWERS AND SCATTERED THUNDERSTORMS MOVING THROUGH
UP UNTIL ABOUT 08Z OR SO. CONDITIONS COULD GET AS LOW AS IFR IN
HEAVIER SHOWERS. LOW-LEVEL WIND SHEAR POSSIBLE AT ALL TERMINALS
WITH A 40-50 KT LOW-LEVEL JET OVERHEAD DURING THE OVERNIGHT
HOURS. WINDS OUT OF THE WEST/SOUTHWEST AROUND 10-15 KT, BECOMING
WEST/NORTHWEST AROUND OR SHORTLY BEFORE DAYBREAK THURSDAY.
OUTLOOK...
THURSDAY...CONDITIONS GRADUALLY IMPROVING TO VFR BY MID DAY. NW
WINDS GUSTING UP TO 35 KT.
FRIDAY THROUGH SUNDAY...PREVAILING VFR. ON FRIDAY, WINDS COULD
GUST TO 30 KT.
MARINE
SOUTH-SOUTHWEST WINDS AROUND 10-15 KT ARE EXPECTED THROUGH
TONIGHT WITH SEAS AROUND 2-3 FEET. AREAS OF PATCHY MARINE FOG
THROUGH THE REMAINDER OF THE DAY. ANOTHER ROUND OF DENSE MARINE
FOG POSSIBLE TONIGHT INTO EARLY WEDNESDAY MORNING.
WINDS INCREASE ON WEDNESDAY TO AROUND 15 KNOTS WITH GUSTS UP TO
25 KNOTS POSSIBLE. A CHANCE (15-30%) FOR SHOWERS IN THE
AFTERNOON.
OUTLOOK...
WEDNESDAY NIGHT...SCA CONDITIONS LIKELY DEVELOPING WITH
INCREASING WINDS AND SEAS. CHANCE (25-45%) FOR SHOWERS AND
THUNDERSTORMS.
THURSDAY...SCA CONDITIONS ARE LIKELY TO CONTINUE THROUGH MUCH,
IF NOT ALL OF THE DAY TIME HOURS. A LULL IN SCA CONDITIONS IS
LIKELY THURSDAY NIGHT.
FRIDAY...SCA CONDITIONS COULD REDEVELOP, ESPECIALLY FRIDAY
AFTERNOON INTO FRIDAY NIGHT.
SATURDAY...ELEVATED SEAS MAY LINGER INTO SATURDAY MORNING.
OTHERWISE, WINDS AND SEAS SHOULD BE BELOW SCA CRITERIA.
SUNDAY...SCA CONDITIONS MAY REDEVELOP, PRIMARILY LATE IN THE
DAY.
CLIMATE
SIX RECORD HIGH TEMPERATURES WERE SET ON TUESDAY, MARCH 10TH.
THIS INCLUDED ALLENTOWN, GEORGETOWN, MOUNT POCONO, PHILADELPHIA,
READING, AND WILMINGTON. THESE WERE ALL IN THE TOP 5 EARLIEST
80 DEGREE DAYS ON RECORD. THE EARLIEST 80 DEGREE DAY ON RECORD
WAS TIED AT THE ATLANTIC CITY AIRPORT.
NEAR RECORD HIGH TEMPERATURES ARE FORECAST FOR MARCH 11TH.
RECORDS FOR OUR CLIMATE SITES ARE LISTED BELOW:
RECORD WARMEST LOW TEMPERATURES: MARCH 11
SITE............................RECORD/YEAR
ALLENTOWN (ABE).....................44/2006
AC AIRPORT (ACY)....................48/1955
AC MARINA (55N).....................51/2016
GEORGETOWN (GED)....................55/1955 & 1986
MOUNT POCONO (MPO)..................47/1955
PHILADELPHIA (PHL)..................54/1955
READING (RDG).......................51/1955
TRENTON (TTN).......................51/1955
WILMINGTON (ILG)....................48/1955
RECORD HIGH TEMPERATURES: MARCH 11
SITE............................RECORD/YEAR
ALLENTOWN (ABE).....................73/2021
AC AIRPORT (ACY)....................79/1967
AC MARINA (55N).....................70/1879
GEORGETOWN (GED)....................77/2021
MOUNT POCONO (MPO)..................66/1977
PHILADELPHIA (PHL)..................74/2021
READING (RDG).......................77/2021
TRENTON (TTN).......................73/2021
WILMINGTON (ILG)....................74/2021
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
DISCUSSION...AKL/GORSE/HOEFLICH/JOHNSON
AVIATION...AKL/HOEFLICH/JOHNSON
MARINE...AKL/HOEFLICH/JOHNSON
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