543
FXUS61 KPHI 151049
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
649 AM EDT WED JUL 15 2026
WHAT HAS CHANGED
SMOKE FROM CANADIAN WILDFIRES APPEARS INCREASINGLY LIKELY TO
IMPACT THE REGION WITH SMOKY CONDITIONS BEGINNING TONIGHT
THROUGH THURSDAY, AND POTENTIALLY LINGERING THROUGH FRIDAY INTO
SATURDAY AS WELL. OTHERWISE, NO SIGNIFICANT CHANGES TO THE
FORECAST.
KEY MESSAGES
1. ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE END OF
THE WEEK. TODAY WILL BE THE HOTTEST DAY OF THE STRETCH, WITH
DANGEROUSLY HOT AND HUMID CONDITIONS EXPECTED. EXTREME HEAT
WARNINGS AND HEAT ADVISORIES ARE IN EFFECT FOR OUR ENTIRE
FORECAST AREA FOR TODAY.
2. A COLD FRONT WILL PASS THROUGH THE REGION LATE THIS AFTERNOON
INTO TONIGHT. ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
POSSIBLE IN THE AFTERNOON AND EARLY EVENING HOURS FOR PARTS OF
THE AREA, SOME OF WHICH COULD BE SEVERE. THE FRONT WILL ALSO
USHER IN SMOKE FROM CANADIAN WILDFIRES, WHICH LOOKS TO PERMEATE
THE REGION BEGINNING TONIGHT THROUGH THURSDAY, AND POTENTIALLY
LINGERING THROUGH FRIDAY INTO SATURDAY.
3. TONIGHT'S COLD FRONT PASSAGE WILL USHER IN SMOKE FROM
CANADIAN WILDFIRES, WHICH LOOKS TO PERMEATE THE REGION BEGINNING
TONIGHT THROUGH THURSDAY, AND POTENTIALLY LINGERING THROUGH
FRIDAY INTO SATURDAY.
4. THE WEEKEND IS SHAPING UP TO BE ACTIVE AND UNSETTLED WITH
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY. SOME STORMS
COULD BE SEVERE AND ALSO MAY PRODUCE HEAVY RAINFALL LEADING TO
FLASH FLOODING.
DISCUSSION
KEY MESSAGE 1...ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH
THE END OF THE WEEK. TODAY WILL BE THE HOTTEST DAY OF THE
STRETCH, WITH DANGEROUSLY HOT AND HUMID CONDITIONS EXPECTED.
EXTREME HEAT WARNINGS AND HEAT ADVISORIES ARE IN EFFECT FOR OUR
ENTIRE FORECAST AREA FOR TODAY.
HEAT AND HUMIDITY WILL PEAK TODAY AS STRONG UPPER RIDGING
REMAINS TO OUR SOUTHWEST. A LOW PRESSURE SYSTEM MOVING THROUGH
EASTERN CANADA WILL RESULT IN WARM ADVECTION AMID WESTERLY FLOW.
HIGH TEMPERATURES ARE FORECAST TO RANGE FROM THE MID 90S TO
NEAR 100 DEGREES IN MOST AREAS, HOTTEST ALONG AND SOUTHEAST OF
I-95, WITH INCREASING HUMIDITY. WHILE SOME AREAS WILL LIKELY
REACH THE CENTURY MARK AGAIN, IT WILL NOT BE QUITE TO THE
MAGNITUDE THAT WE EXPERIENCED TO START JULY. HUMIDITY WILL BE A
LITTLE LESS AS WELL, AND THE HOTTEST CONDITIONS WILL ONLY LAST
FOR ONE DAY. HOWEVER, HEAT INDEX VALUES ARE STILL FORECAST TO
RANGE FROM 100-109 DEGREES FOR MOST OF THE AREA, AGAIN HOTTEST
FROM ALONG AND SOUTHEAST OF I-95. A MODEST WESTERLY, OFFSHORE
WIND NEAR 10-15 MPH SHOULD HELP KEEP THE SEA BREEZE FROM MAKING
MUCH INLAND PROGRESS DURING THE AFTERNOON HOURS. THUS, WE EXPECT
HIGH TEMPERATURES IN THE MID TO UPPER 90S AND HEAT INDICES NEAR
100-105 DEGREES EVEN FOR THE NEW JERSEY SHORE AND DELAWARE
BEACHES.
THE CANADIAN WILDFIRE SMOKE DOES NOT LOOK TO PLAY MUCH OF A
FACTOR IN TODAY'S TEMPERATURES AND HEATING, AS GUIDANCE
INDICATES WE'LL BE IN A CLEAR SPOT BETWEEN SMOKE PLUMES ALOFT TO
OUR NORTH AND SOUTHWEST.
A WEAK COLD FRONT WHICH PASS INTO THE AREA TONIGHT, WHICH WILL
KNOCK DOWN TEMPERATURES AND DEWPOINTS A BIT. HOWEVER, THURSDAY
WILL STILL BE QUITE HOT, WITH MAXIMUM HEAT INDICES IN THE UPPER
90S TO LOW 100S ALONG AND SOUTHEAST OF I-95. IT IS POSSIBLE SOME
ADDITIONAL HEAT ADVISORIES COULD BE NEEDED ON THURSDAY FOR OUR
SOUTHERN ZONES, HOWEVER THE WILDFIRE SMOKE COUPLE PUT A DAMPER
ON DAYTIME HEATING. THUS, WE DO NOT CURRENTLY HAVE ANY HEAT
RELATED HEADLINES UP FOR THURSDAY STILL, AS THIS REMAINS
UNCERTAIN. FRIDAY LOOKS TO BRING MORE RELIEF FROM THE HUMIDITY
AT LEAST, AS DRIER DEWPOINTS ADVECT IN FROM THE NORTH DESPITE
HIGHS IN THE LOW TO MID 90S REMAINING FOR SOME AREAS.
KEY MESSAGE 2...A COLD FRONT WILL PASS THROUGH THE REGION LATE
THIS AFTERNOON INTO TONIGHT. ISOLATED TO SCATTERED THUNDERSTORMS
WILL BE POSSIBLE IN THE AFTERNOON AND EARLY EVENING HOURS FOR
PARTS OF THE AREA, SOME OF WHICH COULD BE SEVERE.
MOST OF TODAY IS STILL EXPECTED TO BE DRY, WITH INCREASINGLY
HOT AND HUMID CONDITIONS AHEAD OF AN APPROACHING COLD FRONT.
HOWEVER, CONCERN HAS INCREASED SOMEWHAT THAT ISOLATED TO
SCATTERED STORMS COULD FORM ACROSS THE NORTHERN HALF OF THE AREA
DURING THE LATE AFTERNOON HOURS AND CONTINUE INTO THE EVENING.
WHILE MID-LEVEL RIDGING WILL BE IN PLACE TO START THE DAY, IT
WILL SLOWLY BECOME SUPPRESSED TO THE SOUTH OF THE REGION THROUGH
THE AFTERNOON HOURS. A SHORTWAVE LOOKS TO DIG SOUTHEASTWARD
NORTH OF THE REGION ACROSS PORTIONS OF NEW ENGLAND. WHILE THE
SHORTWAVE APPEARS LIKELY TO REMAIN MOSTLY NORTH OF THE REGION,
IT WILL STILL CAUSE HEIGHT FALLS THROUGH THE AFTERNOON AND INTO
THE EVENING, WITH H5 FLOW ON THE ORDER OF 50-55 KT OVERSPREADING
THE AREA. THE ENVIRONMENT DURING THE AFTERNOON AND EARLY
EVENING HOURS AHEAD OF THE COLD FRONT WILL BECOME STRONGLY
UNSTABLE, WITH SBCAPE VALUES OF 2000-2500 J/KG. WITH SOME MIXING
TAKING PLACE, SURFACE DEWPOINTS WILL LIKELY FALL INTO THE UPPER
60S F. LOW-LEVEL LAPSE RATES WILL BE QUITE STEEP, WITH 0-3 KM
LAPSE RATES NEAR DRY ADIABATIC. MID-LEVEL DRY AIR FROM
SUBSIDENCE WILL CONTRIBUTE TO VERY HIGH DCAPE VALUES AROUND
1200-1500 J/KG. WITH THE ENHANCED MID-LEVEL FLOW OVERSPREADING
THE REGION, EFFECTIVE SHEAR WILL RANGE FROM 40-50 KT, GREATEST
ACROSS NORTHERN PORTIONS OF THE AREA. ALL OF THIS BEING SAID,
THE ENVIRONMENT IN PLACE WILL BE CONDITIONALLY SUPPORTIVE OF
SEVERE WINDS, AND PERHAPS SOME MARGINALLY SEVERE HAIL AS WELL,
FOR ANY STRONGER STORMS THAT ARE ABLE TO DEVELOP.
FORCING IS STILL EXPECTED TO BE SOMEWHAT WEAK, SO STORM
COVERAGE IS EXPECTED TO BE LIMITED. WE HAVE MAINTAINED POPS
FROM THE PHILLY METRO NORTHWARD TO AROUND 20%. ANY ISOLATED
STORMS THAT DEVELOP SHOULD TRACK SOUTHEASTWARD INTO THE EVENING
HOURS BEFORE RUNNING INTO INCREASING INHIBITION AND DECREASING
INSTABILITY, THEREFORE, IT CURRENTLY APPEARS UNLIKELY THAT ANY
CONVECTION WOULD MAKE IT MUCH FARTHER SOUTH THAN THE PHILLY
METRO AREA.
KEY MESSAGE 3...TONIGHT'S COLD FRONT PASSAGE WILL USHER IN
SMOKE FROM CANADIAN WILDFIRES, WHICH LOOKS TO PERMEATE THE
REGION BEGINNING TONIGHT THROUGH THURSDAY, AND POTENTIALLY
LINGERING THROUGH FRIDAY INTO SATURDAY.
THE LATEST HI-RES GUIDANCE CONTINUES TO INDICATE NEAR SURFACE
SMOKE THE WILDFIRES IN WESTERN ONTARIO WILL SPREAD INTO THE
REGION FOLLOWING TONIGHT'S COLD FRONTAL PASSAGE. THE SMOKE
APPEARS LIKELY TO PERSIST IN THE AREA THROUGH THURSDAY AND
THURSDAY NIGHT, AND POTENTIALLY LINGERING THROUGH FRIDAY INTO
SATURDAY AS WELL. THE SMOKE IS ANTICIPATED TO RESULT IN
VISIBILITY RESTRICTIONS AND POTENTIAL FOR POOR AIR QUALITY, BUT
EXACTLY TO WHAT DEGREE THIS MAY BE IS UNCERTAIN. THIS SMOKE
EVENT IS NOT CURRENTLY ANTICIPATED TO BE AS SEVERE AS THE JUNE
2023 EVENT, BUT THIS WILL BE DIFFICULT TO PREDICT AHEAD OF TIME.
FOR MORE INFORMATION ABOUT AIR QUALITY IN YOUR AREA, VISIT YOUR
STATE DEPARTMENT OF ENVIRONMENTAL PROTECTION AGENCY. WE WILL
ALSO RELAY ANY AIR QUALITY ALERTS THEY MAY ISSUE ON OUR
WEBSITE.
KEY MESSAGE 4...THE WEEKEND IS SHAPING UP TO BE ACTIVE AND
UNSETTLED WITH CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY.
SOME STORMS COULD BE SEVERE AND ALSO MAY PRODUCE HEAVY RAINFALL
LEADING TO FLASH FLOODING.
WE ARE STILL SEVERAL DAYS OUT, BUT ARE MONITORING THE SEVERE
WEATHER SETUP AS WE GET INTO THE WEEKEND.
ANOTHER COLD FRONT WILL APPROACH ON FRIDAY INTO FRIDAY NIGHT.
THE DAYTIME FRIDAY LOOKS DRY AT THIS POINT, BUT SHOWERS AND
STORMS MAY INCREASE IN COVERAGE INTO THE OVERNIGHT PERIOD.
GUIDANCE STILL FOCUSES STORM CHANCES WHEN THE FRONT FINALLY
SINKS INTO THE REGION SATURDAY, WHEN UPPER LEVEL SUPPORT FOR
FORCING WILL ALSO BE MAXIMIZED. THE FRONT WILL STAY OVER OR AT
LEAST NEAR THE REGION INTO SUNDAY. AS IS OFTEN THE CASE WITH
THESE PATTERNS FOLLOWING A BUILDING HEAT PATTERN MID WEEK, THERE
IS SOME POTENTIAL FOR BOTH SEVERE THREATS AND HEAVY RAIN/FLASH
FLOODING THREAT. AT THIS EARLY VANTAGE POINT THE SHEAR LOOKS TO
BE MODERATE TO POTENTIALLY STRONG WITH THE MAIN QUESTION BEING
HOW UNSTABLE IT WILL GET. THIS WILL DETERMINE THE EXTENT OF ANY
SEVERE WEATHER THREAT BUT AT THIS POINT WE SEE AT LEAST SOME
POTENTIAL FOR SEVERE THREATS. PRECIPITABLE WATER VALUES WILL
ALSO BE INCREASING TO AROUND 2+ INCHES. THAT IS WELL ABOUT THE
90TH PERCENTILE FOR THIS TIME OF YEAR, INCREASING THE RISK FOR
HEAVY RAIN/FLASH FLOODING.
THERE'S UNCERTAINTY THOUGH REGARDING HOW FAST THIS FRONT PUSHES
THROUGH AND ALSO WHETHER IT MAY GET HUNG UP NEAR THE AREA INTO
EARLY NEXT WEEK. IF IT MOVES THROUGH FASTER AS THE GFS IS
INDICATING, THINGS COULD START TO CLEAR OUT BY LATER SUNDAY
AFTERNOON WITH FAIR WEATHER TO FOLLOW FOR MONDAY. HOWEVER THE
ECMWF HANGS UP THE FRONT OVER THE AREA INTO NEXT MONDAY WITH
CONTINUING CHANCES FOR SHOWERS AND STORMS. REGARDLESS, CHANCES
FOR SHOWERS AND STORMS WILL REMAIN INTO EARLY NEXT WEEK AS WELL,
BUT DETAILS ARE VERY UNCLEAR AT THE MOMENT.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...PRIMARILY VFR. SMOKE SHOULD REMAIN NORTH OF OUR AREA
THROUGH AT LEAST 21Z. ISOLATED STORMS ARE POSSIBLE AFTER AROUND
20Z FOR RDG/ABE/TTN/PNE/PHL, WHICH COULD LEAD TO BRIEF
RESTRICTIONS, BUT CONFIDENCE IS NOT CURRENTLY HIGH ENOUGH TO
INCLUDE IN THE TAFS. WEST WINDS INCREASING TO AROUND 10 KTS WITH
GUSTS 15-20 KTS. HIGH CONFIDENCE IN PREVAILING VFR AND WINDS.
TONIGHT...MVFR VISIBILITY FROM SMOKE APPEARS INCREASINGLY
LIKELY TO IMPACT AT LEAST THE I-95 TERMINALS AND NORTH,
BEGINNING BETWEEN 00-05Z FROM NORTH TO SOUTH. WESTERLY WINDS
NEAR 10 KTS EARLY WILL SHIFT NORTHWEST OR NORTH AROUND 5-10 KTS
FOLLOWING A FRONTAL PASSAGE, WHICH WILL ALSO SIGNAL THE
BEGINNING OF VISIBILITY RESTRICTIONS. MODERATE CONFIDENCE
OVERALL.
OUTLOOK...
THURSDAY THROUGH THURSDAY NIGHT...MVFR VISIBILITY IS LIKELY TO
BE PREVALENT DURING THIS PERIOD DUE TO CANADIAN WILDFIRE SMOKE,
THOUGH COULD IMPROVE TO VFR AT TIMES ESPECIALLY EARLY IN THE DAY.
VISIBILITY COULD DROP NEAR IFR BETWEEN 18Z AND 00Z. WESTERLY
WINDS 10-15 KTS, WITH GUSTS UP TO 20 KTS. HIGH CONFIDENCE IN
SMOKE RESULTING IN VISIBILITY RESTRICTIONS AT TIMES, BUT LOW
CONFIDENCE IN DETAILS.
FRIDAY THROUGH SUNDAY...RESTRICTIONS WILL BE POSSIBLE IN
ISOLATED TO SCATTERED SHOWERS AND STORMS, ESPECIALLY SATURDAY
AND SUNDAY. SMOKE MAY ALSO LINGER DURING THIS PERIOD AS WELL,
ESPECIALLY FRIDAY.
MARINE
WEST TO SOUTHWEST WINDS 10-15 KTS AND SEAS 1-3 FEET. AN
ISOLATED THUNDERSTORM WITH GUSTY WINDS POSSIBLE NORTH OF
ATLANTIC CITY THIS EVENING.
SMOKE FROM CANADIAN WILDFIRES WILL FILTER INTO THE REGION
OVERNIGHT WEDNESDAY NIGHT, POTENTIALLY CAUSING VISIBILITY
RESTRICTIONS AS LOW AS 3 NM.
OUTLOOK...
THURSDAY THROUGH FRIDAY...CANADIAN WILDFIRE SMOKE MAY CAUSE
VISIBILITY RESTRICTIONS AT TIMES. OTHERWISE, FAIR WEATHER AND NO
MARINE HAZARDS ANTICIPATED.
SATURDAY THROUGH SATURDAY NIGHT...SOUTH TO SOUTHWESTERLY WINDS
COULD APPROACH ADVISORY CRITERIA, WITH 10-15 KT WINDS AND GUSTS
20-25 KT. SEAS GENERALLY UNDER 5 FEET. SHOWERS AND THUNDERSTORMS
LIKELY. SMOKE MAY ALSO LINGER DURING THIS PERIOD.
SUNDAY...NO MARINE HAZARDS CURRENTLY ANTICIPATED WITH WINDS
UNDER 25 KTS AND SEAS UNDER 5 FEET. SCATTERED SHOWERS AND
THUNDERSTORMS POSSIBLE.
RIP CURRENTS...
TODAY, WEST WINDS WILL AVERAGE 10 TO 15 MPH WITH A LIGHT
SOUTHEAST SWELL WITH A PERIOD OF 6 TO 8 SECONDS. BREAKING WAVES
WILL AVERAGE 1 TO 2 FEET. AS A RESULT, THERE IS A LOW RISK FOR
THE DEVELOPMENT OF DANGEROUS AND LIFE THREATENING RIP CURRENTS
AT THE JERSEY SHORE AND AT DELAWARE BEACHES.
ON THURSDAY, SOUTH TO SOUTHWEST WINDS WILL AVERAGE 10 TO 15 MPH
WITH A LIGHT SOUTHEAST SWELL WITH A PERIOD OF 6 TO 8 SECONDS.
BREAKING WAVES WILL AVERAGE 1 TO 2 FEET. AS A RESULT, THERE IS A
LOW RISK FOR THE DEVELOPMENT OF DANGEROUS AND LIFE THREATENING
RIP CURRENTS AT THE JERSEY SHORE AND AT DELAWARE BEACHES.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
CLIMATE
A BRIEF 1-DAY SPIKE IN TEMPERATURES IS EXPECTED TODAY, WITH
HIGHS LIKELY TO APPROACH RECORDS. HERE ARE THE RECORDS FOR
WEDNESDAY, JULY 15:
ALLENTOWN/ABE 98 IN 1995
AC AIRPORT/ACY 100 IN 1995
AC MARINA/55N 99 IN 1995
GEORGETOWN/GED 96 IN 2024 AND 1993
MOUNT POCONO/MPO 92 IN 1954
PHILADELPHIA/PHL 103 IN 1995
READING/RDG 100 IN 1995
TRENTON/TTN 101 IN 1995
WILMINGTON/ILG 99 IN 1997 AND 1995
PHI WATCHES/WARNINGS/ADVISORIES
PA...EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR PAZ070-071-104-106.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR PAZ054-055-060>062-101>103-105.
NJ...EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR NJZ010-012>015-017>020-027.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR NJZ001-007>009-016-021>026.
DE...EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR DEZ001.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR DEZ002>004.
MD...HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR MDZ012-015-019-020.
MARINE...NONE.
DISCUSSION...COOPER/JOHNSON/STAARMANN
AVIATION...STAARMANN
MARINE...MPS/STAARMANN
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