An approaching cold front produced strong to severe thunderstorms in and around the local Philadelphia area during the early evening of the 16th.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PHI wrote it up.
An approaching cold front produced strong to severe thunderstorms in and around the local Philadelphia area during the early evening of the 16th.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Jul 16, 2:29 PM EST, 3 hours 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 329 PM EDT THU JUL 16 2009 .SYNOPSIS... WEAK LOW PRESSURE WILL DRIFT OFF TO THE EAST TONIGHT. ANOTHER AREA OF LOW PRESSURE IS FORECAST TO DEVELOP AS IT MOVES IN FROM THE SOUTHWEST FRIDAY. THIS LOW WILL MOVE ACROSS OUR AREA FRIDAY NIGHT AND HEAD OFF TO THE NORTHEAST SATURDAY. THE COLD FRONT TRAILING FROM THIS LOW WILL BECOME ALMOST STATIONARY TO OUR SOUTH AND EAST WELL INTO NEXT WEEK AS HIGH PRESSURE ATTEMPTS TO PUSH IN FROM THE NORTHWEST. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... TODAYS DAYTIME HEATING IS KICKING OFF A ROUND OF SCATTERED SHOWERS AND TSTMS. WIDESPREAD SEVERE WEATHER IS NOT EXPECTED, BUT AN ISOLATED STRONG STORM COULD APPROACH SEVERE CRITERIA, ESPECIALLY IN OUR NORTHERN AREAS. THE ACTIVITY IS EXPECTED TO DIMINISH AFTER SUNSET AND SHOULD BE OVER BY OR SHORTLY AFTER MIDNIGHT. IT FINALLY FEELS LIKE SUMMER TODAY WITH HIGHS IN THE 80S TO LOW 90S AND DEW POINTS IN THE 60S. OVERNIGHT LOWS WILL REMAIN ON THE MILD SIDE, RANGING FROM THE UPPER 50S IN THE POCONOS TO THE LOWER 70S SOUTHERN AND URBAN AREAS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... FRIDAY WILL START OUT DRY, AND FOR MANY SECTIONS WILL REMAIN THAT WAY FOR MUCH OF THE DAY. AN APPROACHING AND DEVELOPING LOW PRESSURE SYSTEM WILL BRING SHOWERS AND TSTMS FROM THE AFTERNOON INTO THE NIGHT. THEYLL BE MOVING IN FROM THE SOUTHWEST, PROBABLY NOT REACHING OUT NORTHEAST AREAS UNTIL LATE AFTERNOON OR EVENING. MOST OF THE SHOWER/TSTM ACTIVITY WILL OCCUR EARLY FRIDAY NIGHT AS THE LOW PRESSURE SYSTEM CROSS OUR AREA. STRONG STORMS AND HEAVY RAIN ARE POSSIBLE UNTIL AROUND MIDNIGHT. THE ACTIVITY WILL BE DIMINISHING FROM SOUTHWEST TO NORTHEAST AFTER MIDNIGHT. BY DAYBREAK, MOST OF THE SHOWERS WILL BE OVER, BUT COULD STILL BE A LINGERING SHOWER IN THE NORTH SATURDAY MORNING. WITH CAA PUSHING IN SATURDAY, CANT RULE OUT THE POSSIBILITY FOR ADDITIONAL POP UP SHOWERS OR TSTMS, SO WILL CARRY CHC AND SLGT CHC POPS INTO THE EVENING HOURS. THAT ACTIVITY SHOULD END BY MIDNIGHT WITH PARTIAL CLEARING SETTING IN DURING THE EARLY MORNING HOURS. FRIDAY WILL BE ANOTHER WARM HUMID DAY WITH HIGHS MAINLY IN THE 80S. LOWS FRIDAY NIGHT WILL ONCE AGAIN BE MAINLY IN THE 60S. HIGHS ON SATURDAY WILL BE SLIGHTLY LOWER WITH READINGS IN THE MID 70S TO MID 80S. RELATIVE HUMIDITIES WILL ALSO BE DOWN A BIT. AS COOLER AIR WILL MOVES IN, LOW TEMPERATURES SATURDAY NIGHT WILL DROP INTO THE MID 50S TO MID 60S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... THE MODEL GUIDANCE CONTINUES TO INDICATE A RATHER AMPLIFIED UPPER-LEVEL TROUGH SETTLING ACROSS THE EASTERN U.S. HOWEVER, THERE STILL REMAINS SOME UNCERTAINTY ON HOW QUICKLY THIS FEATURE BREAKS DOWN AS IT LIFTS NORTHEASTWARD DURING NEXT WEEK. THE GFS CONTINUES TO RETROGRADE THE ATLANTIC HIGH FASTER THAN OTHER MODELS. THIS WOULD FLATTEN THE TROUGH BY MIDWEEK. THE ECMWF IS SLOWER AND WEAKER WITH MIGRATING THE HIGH TO THE WEST. THIS WOULD MEAN THAT THE TROUGH WOULD MAINTAIN ITSELF LONGER, PROBABLY THROUGH MUCH OF NEXT WEEK. BASICALLY, WE WILL STAY WITH CONTINUITY. THE FRONTAL BOUNDARY IS FORECAST TO REMAIN JUST OFF TO THE SOUTH AND EAST OF OUR FORECAST AREA. WE WILL KEEP SLIGHT CHANCE TO CHANCE POPS THROUGH THE PERIOD. OBVIOUSLY, THE ENTIRE FORECAST PERIOD WILL NOT BE WET. BUT THE THREAT WILL EXIST FOR SHOWERS OR THUNDERSTORMS WELL INTO THE WEEK. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WEAK WARM AIR ADVECTION TRIGGERED SOME HIGHER LEVEL CLOUDS TO STREAM ACROSS MOST OF THE EIGHT TAF SITES THIS AFTERNOON. A WEAK FRONTAL BOUNDARY WILL SLOWLY MOVE THROUGH THE REGION FROM WEST TO EAST WHICH MAY PRODUCE A FEW SHOWERS AND SCATTERED THUNDERSTORMS THIS AFTERNOON. HAVE PLACED CB IN ALL TAF SITES WITH KRDG, KABE, AND KACY HAVING A BETTER CHANCE OF RECEIVING A VICINITY SHOWER BASED ON RADAR. THE SEABREEZE FRONT HAS BEEN ABLE TO PROPAGATE FAR ENOUGH INLAND THAT CURRENT RADAR TRENDS SHOWED AN ISOLATED SHOWER NEAR KACY. VISIBLE SATELLITE IMAGERY SHOWS A VAST AREA OF STRATOCUMULUS INITIATING IN CENTRAL PENNSYLVANIA AND SOUTHWESTERN NEW JERSEY. THIS WILL CONTINUE THROUGH THE EVENING HOURS WITH SOME OF THE CLOUDS CONSOLIDATING INTO CUMULONIMBUS. THIS SHOULD CONTINUE INTO THE EVENING BEFORE WE LOSE THE EFFECTS OF THE DAYTIME HEATING. TAFS WILL REMAIN MOSTLY VFR THROUGH THE OVERNIGHT HOURS WITH A LIGHTENING SOUTHWEST WIND BECOMING LIGHT AND VARIABLE. EARLY MORNING HAZE MAY AFFECT KMIV FOR A FEW HOURS BUT EVERYWHERE ELSE SHOULD REMAIN WITHOUT RESTRICTIONS. OUTLOOK... WEAK FRONTAL BOUNDARY WILL PUSH THROUGH THE REGION TONIGHT AND ULTIMATELY STALL JUST TO OUR SOUTH AND EAST. MULTIPLE WAVES OF LOW PRESSURE WILL RIDE ALONG THIS FRONT THROUGH THE WEEKEND ENHANCING THE CHANCE OF SHOWERS AND THUNDERSTORMS. && .MARINE... WEAK FRONTAL BOUNDARY WILL PUSH THROUGH ON LATE TONIGHT AND INTO FRIDAY MORNING. THIS BOUNDARY WILL STALL TO THE SOUTH AND EAST THROUGH A BETTER PART OF THE WEEKEND. LOW PRESSURE SYSTEMS WILL CONTINUALLY FORM AND MOVE NORTHEAST ALONG THIS FRONT. IN PARTICULAR, A LOW PRESSURE SYSTEM ON SATURDAY WILL RIDE ALONG THIS BOUNDARY BUT THE UNKNOWN ASPECT WOULD BE THE POSITION OF THE LOW AS IT PROGRESSES. IF THE LOW STAYS OFFSHORE THEN THE WINDS WILL SWING FROM A PREDOMINANTLY SOUTHERLY DIRECTION TO A WEST AND THEN A NORTHWEST DIRECTION. IF THE LOW STAYS OVER LAND THEN THE SHIFT BECOMES NORTHEASTERLY. RIGHT NOW THE THINKING IS THAT THE LOW WILL REMAIN OFFSHORE ENOUGH TO SEE THE WESTERLY FLOW. WAVES ARE EXPECTED TO CLIMB TO 5 FEET WELL OFFSHORE. HOWEVER, THEY SHOULD REMAIN BELOW SMALL CRAFT OVER THE WATERS FOR THE WEEKEND AND EARLY NEXT WEEK AS WINDS REMAIN BETWEEN 10 TO 15 KNOTS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && SYNOPSIS...RPW NEAR TERM...RPW SHORT TERM...RPW LONG TERM...RPW AVIATION...HEAVENER/STAUBER MARINE...HEAVENER/STAUBER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 420 AM EDT THU JUL 16 2009 NJZ001-007>010-012-013-015-PAZ054-055-060>062-067>069-170830- SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-WESTERN MONMOUTH- MERCER-CARBON-MONROE-BERKS-LEHIGH-NORTHAMPTON-CHESTER-MONTGOMERY- BUCKS- 420 AM EDT THU JUL 16 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NEW JERSEY...NORTHERN NEW JERSEY...NORTHWEST NEW JERSEY...EAST CENTRAL PENNSYLVANIA...NORTHEAST PENNSYLVANIA AND SOUTHEAST PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. SCATTERED THUNDERSTORMS ARE ANTICIPATED TO DEVELOP TODAY, ESPECIALLY THIS AFTERNOON AND EARLY EVENING. SOME OF THE STORMS COULD BECOME LOCALLY STRONG TO SEVERE WITH GUSTY WINDS AND HAIL. IN ADDITION, FREQUENT CLOUD TO GROUND LIGHTNING AND LOCALLY HEAVY DOWNPOURS WILL BE POSSIBLE WITH THE THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. DEZ001>004-MDZ008-012-015-019-020-NJZ014-016>027-PAZ070-071-170830- NEW CASTLE-KENT-INLAND SUSSEX-DELAWARE BEACHES-CECIL-KENT MD- QUEEN ANNES-TALBOT-CAROLINE-EASTERN MONMOUTH-SALEM-GLOUCESTER-CAMDEN- NORTHWESTERN BURLINGTON-OCEAN-CUMBERLAND-ATLANTIC-CAPE MAY- ATLANTIC COASTAL CAPE MAY-COASTAL ATLANTIC-COASTAL OCEAN- SOUTHEASTERN BURLINGTON-DELAWARE-PHILADELPHIA- 420 AM EDT THU JUL 16 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL DELAWARE...NORTHERN DELAWARE...SOUTHERN DELAWARE...NORTHEAST MARYLAND...CENTRAL NEW JERSEY...SOUTHERN NEW JERSEY AND SOUTHEAST PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. ANZ430-431-450>455-170830- DELAWARE BAY WATERS NORTH OF EAST POINT NJ TO SLAUGHTER BEACH DE- DELAWARE BAY WATERS SOUTH OF EAST POINT NJ TO SLAUGHTER BEACH DE- COASTAL WATERS FROM SANDY HOOK TO MANASQUAN INLET NJ OUT 20 NM- COASTAL WATERS FROM MANASQUAN INLET TO LITTLE EGG INLET NJ OUT 20 NM- COASTAL WATERS FROM LITTLE EGG INLET TO GREAT EGG INLET NJ OUT 20 NM- COASTAL WATERS FROM GREAT EGG INLET TO CAPE MAY NJ OUT 20 NM- COASTAL WATERS FROM CAPE MAY NJ TO CAPE HENLOPEN DE OUT 20 NM- COASTAL WATERS FROM CAPE HENLOPEN TO FENWICK ISLAND DE OUT 20 NM- 420 AM EDT THU JUL 16 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS AND DELAWARE BAY WATERS. .DAY ONE...TODAY AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 315 PM EDT THU JUL 16 2009 DEZ001-NJZ016-017-162015- GLOUCESTER NJ-NEW CASTLE DE-SALEM NJ- 315 PM EDT THU JUL 16 2009 ...A STRONG THUNDERSTORM WILL AFFECT GLOUCESTER...NEW CASTLE AND SALEM COUNTIES... AT 310 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 4 MILES SOUTH OF WILMINGTON...MOVING EAST AT 25 MPH. THE THUNDERSTORM WILL BE NEAR SALEM AROUND 320 PM...WOODSTOWN... ALLOWAY...SWEDESBORO AROUND 335 PM...MULLICA HILL AROUND 345 PM... ELMER...OLIVET AND GLASSBORO AROUND 400 PM. WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM. SZATKOWSKI
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 501 PM EDT THU JUL 16 2009 DEZ001-NJZ016-017-162230- GLOUCESTER NJ-NEW CASTLE DE-SALEM NJ- 501 PM EDT THU JUL 16 2009 ...A STRONG THUNDERSTORM WILL AFFECT GLOUCESTER...NEW CASTLE AND SALEM COUNTIES... AT 457 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 9 MILES NORTHWEST OF WILMINGTON...MOVING SOUTHEAST AT 20 MPH. THE THUNDERSTORM WILL BE NEAR WILMINGTON... EDGEMOOR AROUND 515 PM...PENNS GROVE...CARNEYS POINT AROUND 530 PM... BECKETT...SWEDESBORO AROUND 545 PM...WOODSTOWN AND MULLICA HILL AROUND 600 PM. WIND GUSTS TO 50 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM. SZATKOWSKI
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 536 PM EDT THU JUL 16 2009 PAZ060-067-068-162230- BERKS PA-CHESTER PA-MONTGOMERY PA- 536 PM EDT THU JUL 16 2009 ...A STRONG THUNDERSTORM WILL AFFECT BERKS...CHESTER AND MONTGOMERY COUNTIES... AT 533 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 15 MILES SOUTH OF READING...MOVING EAST AT 20 MPH. THE THUNDERSTORM WILL BE NEAR GLENMOORE AROUND 545 PM...CHESTER SPRINGS...LIONVILLE AROUND 600 PM...MALVERN...PHOENIXVILLE AROUND 615 PM...CHESTERBROOK AND VALLEY FORGE AROUND 630 PM. WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM. SZATKOWSKI
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 637 PM EDT THU JUL 16 2009 NJZ017>019-027-PAZ067>071-170000- BUCKS PA-CAMDEN NJ-CHESTER PA-DELAWARE PA-GLOUCESTER NJ-MONTGOMERY PA- NORTHWESTERN BURLINGTON NJ-PHILADELPHIA PA-SOUTHEASTERN BURLINGTON NJ- 637 PM EDT THU JUL 16 2009 ...SEVERAL STRONG THUNDERSTORMS WILL AFFECT BUCKS...BURLINGTON... CAMDEN...CHESTER...DELAWARE...GLOUCESTER...MONTGOMERY AND PHILADELPHIA COUNTIES... AT 634 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 7 MILES NORTHWEST OF PHILADELPHIA...MOVING EAST AT 20 MPH. THE THUNDERSTORM WILL BE NEAR WYNDMOOR...WYNCOTE AROUND 645 PM...HOLMESBURG...ROCKLEDGE AROUND 700 PM...DELANCO...RIVERSIDE AROUND 715 PM...WILLINGBORO...EDGEWATER PARK AROUND 730 PM...MOUNT HOLLY AND JACKSONVILLE AROUND 745 PM. OTHER STRONG THUNDERSTORMS IN NORTHEASTERN CHESTER COUNTY ARE ALSO MOVING EAST AT AROUND 20 MILES AN HOUR. WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THESE STORMS. SZATKOWSKI
The Philadelphia radar (KDIX), 68 km away, was scanning. The volume nearest the first event began at 22:53 UTC.
2 hail, 1 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm knocked down several trees within Philadelphia from the West Mount Airy section east to the Wissinoming section. A Skywarn Spotter in Juniata Park estimated wind gusts of between 60 and 65 mph.
Dime to quarter size hail was reported by a Skywarn Spotter in Juniata Park.
A severe thunderstorm dropped penny size hail in Levittown and quarter size hail in Morrisville Village. The thunderstorm also produced wind gusts of about 40 mph in Levittown.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2009Every state in 2009This day in weather historyWarnings in Pennsylvania, July 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 186157, 186156, 186164.