499
FXUS61 KPHI 121047
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
647 AM EDT FRI JUN 12 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES TO THE FORECAST.
KEY MESSAGES
1. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY.
2. DANGEROUS HEAT (NEAR RECORD HEAT) AND HUMIDITY FOR MUCH OF
THE REGION THROUGH TODAY, THEN MUCH LESS HUMID OVER THE WEEKEND.
3. CHANCES FOR SHOWERS AND STORMS WILL RETURN AS A COLD FRONT
PASSES THROUGH LATE SUNDAY INTO SUNDAY NIGHT, THEN TURNING MORE
SEASONABLE THROUGH THE MIDDLE OF NEXT WEEK.
4. WIDESPREAD MINOR COASTAL FLOODING WILL DEVELOP WITH THE
EVENING HIGH TIDE CYCLES SATURDAY AND SUNDAY ALONG THE ATLANTIC
COAST, DELAWARE BAY, AND ON THE TIDAL DELAWARE RIVER AND ITS
TRIBUTARIES.
DISCUSSION
KEY MESSAGE 1...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS
TODAY.
THE PATTERN IN PLACE WILL CONTINUE TO SUPPORT SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS THE REGION LATE THIS AFTERNOON
AND EVENING.
WE WILL BEGIN FEELING THE INFLUENCE OF THE UPPER-LEVEL TROUGH
TO THE WEST OF THE REGION, IN ADDITION TO A COLD FRONT THAT WILL
BE ARRIVING FROM THE WEST. SOME ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS SHOULD FOCUS NEAR AND AHEAD OF THIS FRONT. ONE
POTENTIAL LIMITING FACTOR COVERAGE WISE WILL BE A MID LEVEL JET
STREAK PRODUCING LOCALIZED SUBSIDENCE ACROSS THE CENTER PORTION
OF THE FORECAST AREA, FROM SE PA ACROSS THE PHILLY METRO AND
INTO SOUTHERN NJ. POPS WERE LOWERED IN THIS AREA. STRONG
DESTABILIZATION AND SLIGHTLY BETTER WIND FIELDS ALOFT WILL STILL
SUPPORT A SEVERE THREAT WHERE EVER STORMS DO MATERIALIZE (MOST
LIKELY FOCUSED ACROSS THE SOUTHERN AND NORTHERN PORTIONS OF OUR
AREA).
THE CONVECTIVE EVOLUTION IS MORE UNCERTAIN THAN THE PAST 2 DAYS
GIVEN THE SUBTLE SUBSIDENCE ALOFT LIKELY LIMITING DEVELOPMENT
AND COVERAGE FOR A WHILE THIS AFTERNOON, SO MESOANALYSIS WILL BE
KEY IN FIGURING OUT THESE DETAILS LATER TODAY. OUR ENTIRE AREA
REMAINS HIGHLIGHTED IN A SLIGHT RISK (LEVEL 2 OUT OF 5) FOR
SEVERE THUNDERSTORMS. DAMAGING WINDS WILL ONCE AGAIN BE THE MAIN
THREAT DUE TO THE HIGH DCAPE AND STEEP LOW LEVEL LAPSE RATES.
WEAK LOW LEVEL SHEAR, HIGH WETBULB ZERO HEIGHTS, AND MODEST
INSTABILITY SHOULD RESULT IN LITTLE TO NO THREATS FOR TORNADOES
OR LARGE HAIL.
KEY MESSAGE 2...DANGEROUS HEAT (NEAR RECORD HEAT) AND HUMIDITY
FOR MUCH OF THE REGION THROUGH TODAY, THEN MUCH LESS HUMID OVER
THE WEEKEND.
A MID-LEVEL RIDGE WILL BEGIN TO SLIDE OFFSHORE OF THE MID-
ATLANTIC AND NORTHEAST THROUGH TODAY. AT THE SURFACE, HIGH
PRESSURE REMAINS CENTERED OFF THE SOUTHEAST U.S. COAST WHICH
WILL CONTINUE TO DIRECT A HOT AND HUMID AIRMASS ACROSS OUR AREA.
DANGEROUS HEAT IS EXPECTED TO CONTINUE ACROSS MUCH OF OUR
REGION THROUGH TODAY, WITH SEVERAL RECORD HIGHS LIKELY TO BE
CHALLENGED AGAIN. HIGH TEMPERATURES ARE FORECAST TO PEAK INTO
THE LOW TO MID 90S ACROSS MOST OF THE AREA. TEMPERATURES MAY BE
A DEGREE OR TWO HOTTER TODAY COMPARED TO THURSDAY, AS BETTER
MIXING OUT OF THE DEWPOINTS IN ANTICIPATED. DEWPOINTS WILL
START OUT IN THE LOW TO MID 70S, BUT WITH AFTERNOON HEATING AND
MIXING, THESE SHOULD MIX DOWN TO THE UPPER 60S AND LOW 70S. THIS
STILL RESULTS IN PEAK HEAT INDEX VALUES OF 95 TO 105 DEGREES
ACROSS THE MAJORITY OF THE AREA, OUTSIDE OF THE SOUTHERN
POCONOS. THIS LEVEL OF HEAT AND HUMIDITY CAN BECOME DANGEROUS
QUICKLY FOR SENSITIVE INDIVIDUALS AND THOSE OUTDOORS FOR
EXTENDED PERIODS OF TIME. A HEAT ADVISORY REMAINS IN EFFECT
THROUGH 8 PM TODAY FOR AREAS WHERE THE HEAT INDEX CRITERIA
STARTS AT 96F AND 100F.
A COLD FRONT IS FORECAST TO MOVE THROUGH THE REGION TONIGHT,
WHICH WILL KNOCK THE TEMPERATURES AND ESPECIALLY THE DEWPOINTS
DOWN SEVERAL DEGREES. THOUGH IT WILL STILL BE HOT WITH HIGH
TEMPERATURES IN THE UPPER 80S TO LOW 90S OVER THE WEEKEND,
DEWPOINTS WILL RETURN TO MUCH MORE COMFORTABLE LEVELS (INTO THE
50S IN SOME AREAS SATURDAY). THEREFORE, THE HEAT INDEX WILL NOT
BE MUCH OF A FACTOR IN THE APPARENT TEMPERATURE, AND NO HEAT
HAZARDS ARE ANTICIPATED FOR THE WEEKEND.
KEY MESSAGE 3...CHANCES FOR SHOWERS AND STORMS, INCLUDING A
SLIGHT RISK FOR SEVERE THUNDERSTORMS, WILL RETURN AS A COLD
FRONT PASSES THROUGH LATE SUNDAY INTO SUNDAY NIGHT. TURNING
MORE SEASONABLE THROUGH THE MIDDLE OF NEXT WEEK.
A SHORTWAVE TROUGH WILL PUSH ANOTHER COLD FRONT THROUGH THE
REGION LATE SUNDAY INTO SUNDAY NIGHT. THIS WILL GIVE US ANOTHER
ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS, HOWEVER THIS ONE
WILL BE DIFFERENT THAN THE ACTIVITY WE'RE EXPERIENCING THIS
WEEK. THERE LOOKS TO BE PLENTY OF SYNOPTIC FORCING WITH MORE
SHEAR PRESENT. THE BIGGEST QUESTION AND POTENTIAL LIMITING
FACTOR AS FAR AS THE SEVERE THREAT GOES WITH THIS SETUP WILL BE
INSTABILITY. WE'LL NEED TIME TO ADVECT SUFFICIENT LOW LEVEL
MOISTURE NORTHWARD INTO THE AREA BEFORE THE BEST FORCING AND
SHEAR ARRIVE. SURFACE DEWPOINTS WILL BE THE THING TO WATCH WITH
THIS. THERE WILL BE, AT THE VERY LEAST, SUFFICIENT INSTABILITY
FOR SHOWERS AND STORMS, BUT WE'LL NEED DEWPOINTS NEARING 70
DEGREES TO REALIZE ANY MEANINGFUL SEVERE THREAT. TIMING
VARIATIONS REMAIN AMONG GUIDANCE FOR THE COLD FRONT, WHICH COULD
ALSO MAKE OR BREAK OUR SEVERE THREAT. A FASTER EVOLUTION WILL
LIKELY LEAD TO A LOWER SEVERE THREAT, AND A SLOWER PROGRESSION
SHOULD LEAD TO A GREATER ONE. WE'LL CONTINUE TO MONITOR THIS
POTENTIAL. SPC HAS OUTLOOKED AREAS MAINLY SOUTH OF I-78 IN A
SLIGHT RISK (LEVEL 2 OUT OF 5) FOR SEVERE STORMS.
THE FRONTAL PASSAGE WILL USHER IN A MUCH MORE SEASONABLE
AIRMASS THAT WILL STICK AROUND THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. HIGHS WILL BE IN THE MID 70S TO MID 80S MONDAY
THROUGH WEDNESDAY, WITH LOWS IN THE MID 50S TO LOW 60S.
DEWPOINTS IN THE 50S AND LOW 60S WILL MAKE FOR MUCH MORE
PLEASANT CONDITIONS. CAN'T COMPLETELY RULE OUT A FEW SHOWERS,
BUT OVERALL THE CHANCES FOR RAIN LOOK LOW DURING THIS PERIOD.
KEY MESSAGE 4...WIDESPREAD MINOR COASTAL FLOODING WILL DEVELOP
WITH THE EVENING HIGH TIDE CYCLES SATURDAY AND SUNDAY ALONG THE
ATLANTIC COAST, DELAWARE BAY, AND ON THE TIDAL DELAWARE RIVER
AND ITS TRIBUTARIES.
A NEW MOON THIS WEEKEND WILL RESULT IN HIGHER THAN NORMAL
ASTRONOMICAL TIDES. ASTRONOMICAL TIDES WILL GENERALLY BE 1/2
FOOT LESS THAN MINOR COASTAL FLOODING THRESHOLDS, AND TIDAL
DEPARTURES WILL BE AROUND 1 FOOT OR SO. THIS WILL RESULT IN
WIDESPREAD MINOR COASTAL FLOODING WITH THE EVENING AND NIGHTTIME
HIGH TIDE CYCLES SATURDAY AND SUNDAY, AND POTENTIALLY MONDAY AS
WELL ON THE ATLANTIC COAST AND DELAWARE BAY. THE TIDAL DELAWARE
RIVER AND ITS TRIBUTARIES COULD EXPERIENCE SOME SPOTTY MINOR
TIDAL FLOODING BY SUNDAY NIGHT'S HIGH TIDE, AND POTENTIALLY
MONDAY NIGHT TOO, BUT GENERALLY THESE ASTRONOMICAL TIDE DRIVEN
FLOODING EVENTS PRODUCE MORE NOTEWORTHY IMPACTS FOR THE
ATLANTIC COASTS AND DELAWARE BAY. THE HIGHEST OF THE NEW MOON
TIDES WILL BE SUNDAY NIGHT AND MONDAY NIGHT. TIDAL FLOODING IS
NOT CURRENTLY EXPECTED ALONG THE EASTERN SHORE OF CHESAPEAKE
BAY.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...PREVAILING VFR EXPECTED THROUGH THE PERIOD. BRIEF
RESTRICTIONS ARE POSSIBLE, WITH SCATTERED SHOWERS AND
THUNDERSTORMS, MAINLY AFTER 21Z. WESTERLY WINDS INCREASING TO
NEAR 10 KTS, WITH GUSTS UP TO 20 KTS POSSIBLE AT TIMES AFTER
15Z. HIGH CONFIDENCE IN PREVAILING VFR THROUGH THE DAY, MODERATE
CONFIDENCE IN THUNDER TIMING.
TONIGHT...ANY SHOWERS AND STORMS ENDING BY 03Z, THEN VFR. WINDS
SHIFTING NORTHWESTERLY NEAR 5-10 KTS. HIGH CONFIDENCE.
OUTLOOK...
SATURDAY...VFR. NO SIGNIFICANT WEATHER EXPECTED.
SUNDAY...RESTRICTIONS POSSIBLE WITH THE CHANCE FOR SHOWERS AND
STORMS.
MONDAY...VFR. NO SIGNIFICANT WEATHER EXPECTED.
TUESDAY...RESTRICTIONS POSSIBLE WITH THE CHANCE FOR SHOWERS AND
STORMS.
MARINE
NO PREVAILING MARINE HAZARDS EXPECTED THROUGH TONIGHT. A
SOUTHWEST WIND NEAR 10-15 KTS, WITH OCCASIONAL GUSTS UP TO 20
KTS AND SEAS OF 3-4 FEET. SHOWERS AND THUNDERSTORMS MAY IMPACT
THE NEARSHORE WATERS AND DELAWARE BAY THIS EVENING, WITH BRIEF
STRONG WIND GUSTS POSSIBLE. WINDS SHIFTING NORTHWEST OVERNIGHT.
OUTLOOK...
SATURDAY...NO MARINE HAZARDS ANTICIPATED. WINDS WILL GENERALLY
REMAIN BETWEEN 5-15 KT. SEAS GENERALLY AROUND 2-3 FEET. FAIR
WEATHER EXPECTED.
SUNDAY...A BRIEF PERIOD OF MARGINAL SMALL CRAFT ADVISORY
CONDITIONS ARE POSSIBLE SUNDAY AFTERNOON AND EVENING WITH WIND
GUSTS NEAR 25 KT.
MONDAY AND TUESDAY...NO MARINE HAZARDS ANTICIPATED WITH WINDS
5-10 KT AND SEAS 2-3 FEET.
RIP CURRENTS...
FOR TODAY, A MEDIUM PERIOD 8 SECOND SWELL, OFFSHORE WINDS, AND
BREAKING WAVES 2 FEET OR LESS WILL RESULT IN A LOW RISK FOR
DEVELOPMENT OF RIP CURRENTS AT THE JERSEY SHORE AND DELAWARE
BEACHES.
ON SATURDAY, CONDITIONS WILL BE RELATIVELY SIMILAR, THOUGH THE
DOMINANT PERIOD WILL INCREASE TO AROUND 10 TO 11 SECONDS.
HOWEVER, WITH WINDS OFFSHORE, AND BREAKING WAVES AGAIN 2 FEET OR
LESS, THERE WILL NOT BE MUCH ENERGY IN THE SURF ZONES. THIS
WILL RESULT IN ANOTHER DAY OF A LOW RISK FOR THE DEVELOPMENT OF
RIP CURRENTS.
OCEAN WATER TEMPERATURES ARE MOSTLY IN THE MID TO UPPER 60S.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
CLIMATE
FOUR RECORD HIGH TEMPERATURES WERE SET ON THURSDAY, INCLUDING
THE ATLANTIC CITY MARINA, PHILADELPHIA, WILMINGTON, AND
GEORGETOWN. THE VERY HOT AND HUMID AIRMASS WILL REMAIN ACROSS
OUR AREA THROUGH TODAY. SOME RECORD HIGH AND WARMEST LOW
TEMPERATURES COULD BE CHALLENGED.
LOCATION 6/12 RECORD WARMEST LOW/YEAR
MOUNT POCONO 69/2005
ALLENTOWN 70/1942
READING 75/1958
PHILADELPHIA 75/2015
TRENTON 72/2015 & 2017
ATLANTIC CITY AIRPORT 73/1973 & 2015
ATLANTIC CITY MARINA 79/2016
WILMINGTON 73/2015
GEORGETOWN 73/1947, 1973, 1986, & 2017
LOCATION 6/12 RECORD HIGHS/YEAR
MOUNT POCONO 87/1967
ALLENTOWN 92/1949, 1961, 2015, & 2017
READING 95/1984
PHILADELPHIA 95/1947 & 2015
TRENTON 94/1933
ATLANTIC CITY AIRPORT 94/2017
ATLANTIC CITY MARINA 93/1880 & 1914
WILMINGTON 96/1933
GEORGETOWN 95/2017
PHI WATCHES/WARNINGS/ADVISORIES
PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ060>062-070-
071-101>106.
NJ...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ001-007>010-
012>015-017>020-027.
DE...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR DEZ001.
MD...NONE.
MARINE...NONE.
DISCUSSION...GUZZO/STAARMANN
AVIATION...STAARMANN
MARINE...HOEFLICH/STAARMANN
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