A line of strong to severe thunderstorms formed in the warm sector of the Susquehanna Valley and moved through southeast Pennsylvania during the late afternoon and first half of the evening on the 9th. The line also spawned an EF-1 tornado in Berks County.
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.
A line of strong to severe thunderstorms formed in the warm sector of the Susquehanna Valley and moved through southeast Pennsylvania during the late afternoon and first half of the evening on the 9th. The line also spawned an EF-1 tornado in Berks County. During the evening the line of thunderstorms also caused flash flooding. A warm front lifted northeast into the Lehigh Valley during the afternoon of the 9th. This permitted sufficient daytime heating preceding an approaching cold front. In addition, there was enough shear in the atmosphere for a tornado to occur.
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 9, 4:16 PM EST, 1 hour 6 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 516 PM EDT THU JUL 9 2015 .SYNOPSIS... LOW PRESSURE WILL ADVANCE ALONG AN APPROACHING COLD FRONT THROUGH THE REGION THIS EVENING BEFORE MOVING OFFSHORE LATE TONIGHT. HIGH PRESSURE WILL BUILD IN BEHIND THIS FRONT FOR FRIDAY LASTING THROUGH THE WEEKEND. ON MONDAY A WARM FRONT WILL PROGRESS NORTHWARD INTO OUR AREA BEFORE STALLING AND WAVERING A BIT THROUGH EARLY NEXT WEEK. AS A RESULT, LOW PRESSURE SYSTEMS RIDING ALONG THE FRONT WILL RESULT IN MORE PERIODS OF UNSETTLED WEATHER. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... NO MAJOR CHANGES TO THE NEAR TERM WITH THE EXCEPTION OF A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR MUCH OF OUR REGION WITH THE EXCEPTION OF SOUTHERN DELMARVA. WITH STORMS LESS DISCRETE ON THE SOUTHEN END, THINK THAT THE PRIMARY HAZARD WILL BE STRONG WINDS. PREVIOUS NEAR TERM DISCUSSION...THE GFS INITIALIZATION LOOKED BETTER AT 500MB, WITH THE NAM BETTER AT 850MB AND THE GFS BETTER AGAIN AT 925MB. CAN RGEM/NAM COMPROMISE HANDLING THE PCPN FIELD THE BEST THRU 18Z, WHILE THE GFS SFC POSN IS CLOSEST. SPC WRF LOOKS SLIGHTLY BETTER (1 HR SLOW) THAN THE NSSL WRF WITH ONGOING CONVECTION. LOCALLY THE CLOUDINESS IS SLOWING THE ASCENT OF TEMPERATURES, BUT SFC BASED CAPES WEST OF THE CHESAPEAKE AND IN THE SUSQ VALLEY HAVE ALREADY REACHED BETWEEN 1000 AND 2000J. THE 12Z SUITE OF GUIDANCE IS NOT SHOWING MUCH CHANGE FROM THE OVERNIGHT GUIDANCE. WE ARE STILL SEEING SEVERE WX PARAMETERS (INCLUDING SHERBS) MAXING JUST TO THE WEST OF OUR CWA LATE THIS AFTERNOON. HOWEVER, THERE IS MORE OF A GEOGRAPHIC SPLIT BETWEEN THE HIGHEST SHEAR (NORTH) AND HIGHEST CAPE AND DCAPE (SOUTH) IN AND TO THE WEST OF OUR CWA. THE BETTER DPVA AND CONVERGENT SIDE OF THE LLJ REMAINS FROM ABOUT THE MASON DIXON LINE NORTHWARD. THIS REMAINS THE LOCATIONS WHERE WE HAVE THE MOST ENHANCED WORDING. LLJ THAT WAS CENTERED NEAR ILN THIS MORNING IS PREDICTED TO TRAVERSE OUR CWA THIS EVENING. AS IT DOES PREDICTED SHEAR AND HELICITY INCREASES AND MAXES CLOSE TO 00Z WITHIN OUR CWA. AFTER THAT, THE MODELS ARE ALL SHOWING A PRECIPITUOUS DROP IN INSTABILITY. SO IT REMAINS, THE SOONER THE CONVECTION CAN ARRIVE, THE GREATER THE RISK FOR SEVERITY. THE COLD FRONT ITSELF WILL LAG THE CONVECTION BY A FEW HOURS. THE HRRR IN PARTICULAR SUGGEST A DOUBLE BARREL STRUCTURE TO THE CONVECTION. GIVEN THE FORMER'S EXPECTED ORGANIZATION AS WELL AS LATER TIMING OF SECOND BATCH, DO NOT BELIEVE THE LATTER AREA WILL BE ABLE TO TAP INTO MUCH OF A RECOVERED AIR MASS RECOVER TO BE THAT STRONG. AS FAR AS FLOODING CONCERNS, UNLESS CONVECTION CAN TRAIN, FORWARD MOTION SHOULD INCREASE TO 30 TO 40 KNOTS. WHILE PREDICTED PWATS RISE TO ABOUT 2.5 INCHES, THE STORM MOTION SHOULD BE TOO FAST TO CAUSE WIDESPREAD FLASH FLOODING. POOR DRAINAGE FLOODING THOUGH IS LIKELY TO OCCUR. WE ARE EXPECTING MOST OF THE ACTIVITY TO BE OFFSHORE AFTER MIDNIGHT. A BREEZY NORTHWEST FLOW BEHIND THE CFP OVERNIGHT SHOULD PREVENT MUCH FOG FROM FORMING. MIN TEMPS ARE CLOSE TO STAT GUIDANCE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... AFTER ENDURING SEVERAL DAYS OF HIGH AND UNCOMFORTABLE DEW POINT LEVELS, A MUCH DRIER AIR MASS WILL BE IN PLACE ACROSS OUR CWA. PREDICTED CONVECTIVE TEMPERATURES APPEAR OUT OF REACH, SO NOT THAT MANY CUMULUS SHOULD BE AROUND. MAXIMUM TEMPERATURES, WE USED THE FALLBACK PREDICTED 1000-850MB THICKNESSES GUIDE AND THESE OVERALL LEAN TOWARD THE HIGHER GFS MOS MAX TEMPERATURES. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... GREATER CONFIDENCE IN THE LONGWAVE PATTERN PROVIDING A DRIER FORECAST FRIDAY THROUGH THE WEEKEND AS MID-LEVEL RIDGING RETROGRADES TO OUR SOUTH. AFTERWARDS MEAN TROUGHING SETS UP JUST TO THE EAST- NORTHEAST OF THE REGION WITH MULTIPLE IMPULSES PUSHING THROUGH WITHIN THE WEST-NORTHWEST FLOW ALOFT. FRIDAY - SUNDAY...RIDGING SLIDES BY TO OUR SOUTH BRINGING MASSIVE AMOUNTS OF SUBSIDENCE WITH IT, AND DRIER DEWPOINTS...A WELCOME REPRIEVE. TEMPERATURES WILL REMAIN QUITE SEASONAL RUNNING IN THE MID TO UPPER-80S EACH DAY. MONDAY - THURSDAY...WARM FRONT PASSAGE, FROM WHAT WAS ONCE THE COLD FRONT EARLIER IN THE PERIOD, MOVES BACK TOWARDS THE NORTH ON SUNDAY NIGHT INTO MONDAY. COLD FRONT THEN NEARS FROM THE NORTHWEST LATE ON MONDAY INTO TUESDAY AS TROUGHING TAKES BACK OVER AGAIN. NORTHWEST FLOW ALOFT LOOKS TO PREVAIL AS CENTRAL U.S. RIDGING AMPLIFIES. THIS MAY SEND SEVERAL SHORTWAVES THROUGH THE REGION FROM LATE MONDAY ONWARD...NORTHERN PLAINS MCS SEASON. SEVERAL CHANCES FOR DIURNAL CONVECTION IN A MODIFYING AIRMASS ARE POSSIBLE THROUGH MOST OF NEXT WEEK. TEMPERATURES REMAIN AT OR SLIGHTLY ABOVE NORMAL. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY, AND SURROUNDING AREAS. 18Z TAF MAINTAINED A HIGH TSRA IMPACT ACROSS OUR TERMINAL AREA LATE THIS AFTERNOON AND EARLY THIS EVENING. OVERALL HIGHEST CONFIDENCE OF IMPACT FOR NORTHWEST TERMINALS AND AIRPORTS WITH LOWEST CONFIDENCE OF IMPACT FOR ANY DELMARVA AIRPORTS SOUTH OF KILG. THROUGH THIS EVENING...TERMINALS START VFR WITH WINDS CONTINUING TO BACK MORE TO THE SOUTHWEST AND GUSTINESS INCREASING, GETTING CLOSER TO 20 KNOTS. WE CONTINUE A TWO HOUR WINDOW OF STRONG TSRAS AFFECTING ALL OF OUR TERMINALS. MVFR CONDITIONS ARE QUITE LIKELY WITH IFR NOT OUT OF THE QUESTION. STRONG GUSTY WINDS ALONG WITH HEAVY RAIN LIKELY. HIGHEST SVR CHANCE KRDG AND KABE. NOT SURE ABOUT A DOUBLE BARREL (LESSER SECOND) SHOT AND WE HAVE SHOWERS FOR NOW TO COVER THE CHANCE. LATER THIS EVENING, THE CFP IS PREDICTED WITH WINDS BECOMING WEST WITH CONTINUED GUSTINESS. CIGS AND VSBYS SHOULD QUICKLY BECOME VFR. OVERNIGHT...ENOUGH WIND WE BELIEVE TO PREVENT FOG FROM FORMING. SKIES SHOULD BECOME MOSTLY CLEAR, OR AT THE MOST A SCATTERED VFR DECK LINGERING. FRIDAY...VFR NO CIG EXPECTED. NORTHWEST WINDS AVERAGING 10 TO 15 KNOTS. THERE MIGHT BE AN HOUR OR TWO OF GUSTINESS ONCE BETTER MIXING OCCURS DURING THE MORNING. THIS LOOKS MORE LIKELY AT AIRPORTS FARTHER TO THE NORTHEAST, SO NOT INCLUDED WITH THIS PACKAGE. OUTLOOK... SATURDAY - SUNDAY...VFR. W TO NW WIND UNDER 10 KT. HIGH CONFIDENCE. SUNDAY NIGHT - TUESDAY...MOSTLY VFR. SOME AFTN SHRA/TSRA PSBL. LOW TO MDT CONFIDENCE. && .MARINE... WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH FRIDAY. HOWEVER, DURING THIS EVENING IN THE PRE FRONTAL SOUTHWEST (SOUTHEAST UP DELAWARE BAY) FLOW AND AROUND DAYBREAK IN THE NORTHWEST FLOW ON FRIDAY, WIND GUSTS MAY COME CLOSE. HIGHEST CONCERN DURING THIS PERIOD IS FOR POSSIBLE SPECIAL MARINE WARNINGS THIS EVENING AS A LINE OF THUNDERSTORMS (OR AT LEAST AN AREA) MOVES THROUGH THE AREA WATERS. OUTLOOK... SATURDAY - TUESDAY...SUB-SCA CONDITIONS EXPECTED DURING THE OUTLOOK PERIOD. WINDS WILL BE OUT OF THE NORTH EARLY THIS WEEKEND BEFORE BACKING TOWARDS THE WEST-SOUTHWEST AS HIGH PRESSURE SLIDES BY TO OUR SOUTH...GUSTS UPWARDS OF 15 TO 20 KNOTS THROUGH THE PERIOD. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && SYNOPSIS...YAROSH NEAR TERM...GIGI/JOHNSON SHORT TERM...GIGI LONG TERM...HEAVENER AVIATION...HEAVENER MARINE...GIGI/HEAVENER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 511 PM EDT THU JUL 9 2015 DEZ001-MDZ008-NJZ001-007>010-012-013-015>023-027-PAZ054-055-060>062- 070-071-101>106-102115- NEW CASTLE-CECIL-SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX- WESTERN MONMOUTH-MERCER-SALEM-GLOUCESTER-CAMDEN- NORTHWESTERN BURLINGTON-OCEAN-CUMBERLAND-ATLANTIC-CAPE MAY- SOUTHEASTERN BURLINGTON-CARBON-MONROE-BERKS-LEHIGH-NORTHAMPTON- DELAWARE-PHILADELPHIA-WESTERN CHESTER-EASTERN CHESTER- WESTERN MONTGOMERY-EASTERN MONTGOMERY-UPPER BUCKS-LOWER BUCKS- 511 PM EDT THU JUL 9 2015 ...SEVERE THUNDERSTORM WATCH 398 IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN DELAWARE...NORTHEAST MARYLAND...CENTRAL NEW JERSEY...NORTHERN NEW JERSEY...NORTHWEST NEW JERSEY...SOUTHERN NEW JERSEY...EAST CENTRAL PENNSYLVANIA...NORTHEAST PENNSYLVANIA AND SOUTHEAST PENNSYLVANIA. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. SHOWERS AND THUNDERSTORMS ARE ANTICIPATED FOR THIS AFTERNOON AND EVENING. SOME OF THE RAINFALL COULD BE HEAVY, WHICH MAY RESULT IN LOCALIZED FLASH FLOODING. IN ADDITION, SOME THUNDERSTORMS COULD PRODUCE LOCALLY STRONG DAMAGING WINDS THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. DEZ002-003-MDZ012-015-019-020-102115- KENT-INLAND SUSSEX-KENT MD-QUEEN ANNES-TALBOT-CAROLINE- 511 PM EDT THU JUL 9 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL DELAWARE...SOUTHERN DELAWARE AND NORTHEAST MARYLAND. .DAY ONE...TONIGHT. SHOWERS AND THUNDERSTORMS ARE ANTICIPATED FOR THIS AFTERNOON AND EVENING. SOME OF THE RAINFALL COULD BE HEAVY, WHICH MAY RESULT IN LOCALIZED FLASH FLOODING. IN ADDITION, SOME THUNDERSTORMS COULD PRODUCE LOCALLY STRONG DAMAGING WINDS THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED. NJZ014-024>026-102115- EASTERN MONMOUTH-ATLANTIC COASTAL CAPE MAY-COASTAL ATLANTIC- COASTAL OCEAN- 511 PM EDT THU JUL 9 2015 ...SEVERE THUNDERSTORM WATCH 398 IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NEW JERSEY AND SOUTHERN NEW JERSEY. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. SHOWERS AND THUNDERSTORMS ARE ANTICIPATED FOR THIS AFTERNOON AND EVENING. SOME OF THE RAINFALL COULD BE HEAVY, WHICH MAY RESULT IN LOCALIZED FLASH FLOODING. IN ADDITION, SOME THUNDERSTORMS COULD PRODUCE LOCALLY STRONG DAMAGING WINDS THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. DEZ004-102115- DELAWARE BEACHES- 511 PM EDT THU JUL 9 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN DELAWARE. .DAY ONE...TONIGHT. SHOWERS AND THUNDERSTORMS ARE ANTICIPATED FOR THIS AFTERNOON AND EVENING. SOME OF THE RAINFALL COULD BE HEAVY, WHICH MAY RESULT IN LOCALIZED FLASH FLOODING. IN ADDITION, SOME THUNDERSTORMS COULD PRODUCE LOCALLY STRONG DAMAGING WINDS THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED. ANZ450>455-102115- 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- 511 PM EDT THU JUL 9 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS. .DAY ONE...TONIGHT. SOME THUNDERSTORMS THIS AFTERNOON AND EVENING COULD PRODUCE LOCALLY STRONG WINDS AND HIGHER WAVES. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED. ANZ430-431-102115- DELAWARE BAY WATERS NORTH OF EAST POINT NJ TO SLAUGHTER BEACH DE- DELAWARE BAY WATERS SOUTH OF EAST POINT NJ TO SLAUGHTER BEACH DE- 511 PM EDT THU JUL 9 2015 ...SEVERE THUNDERSTORM WATCH 398 IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR DELAWARE BAY WATERS. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. SOME THUNDERSTORMS THIS AFTERNOON AND EVENING COULD PRODUCE LOCALLY STRONG WINDS AND HIGHER WAVES. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The State College radar (KCCX), 157 km away, was scanning. The volume nearest the first event began at 22:21 UTC.
8 thunderstorm wind, 1 tornado. Local standard time, as filed.
A severe thunderstorm knocked down trees and wires that damaged five homes in Rehrersburg (Tulpehocken Township).
An EF1 tornado occurred in Tilden Township in Berks County and injured one person. The tornado touched down near Stone Road and moved eastnortheast, passing through the Blue Mountain Academy before crossing Mountain Road into a campground area before lifting. The most significant damage occurred to the Blue Mountain Elementary School. The roof of the school was completely removed by the tornado. The building is a total loss. The 52-year-old principal inside the school at the time of the tornado was injured and was found covered by ceiling tiles. Pieces of the roof were found hundreds of yards away in trees. Hardwood trees were snapped along the tornado's path with a soybean field having debris dragged through it with visible arcing marks.
The estimated path length of the EF-1 tornado was three-quarters of a mile with a maximum path width of 75 yards. The estimated maximum wind speed was 105 mph.
A line of severe thunderstorms tore down numerous trees and wires across the northern tier of Chester County.
A line of strong to severe thunderstorms tore down trees and wires across the northeast half of Montgomery County.
Another segment of a line of severe thunderstorms tore down numerous trees and wires across the southern tier of Chester County.
A severe thunderstorms tore down large tree limbs at the intersection of DeKalb and Germantown Pikes in Norristown.
The gust front of a severe thunderstorm damaged the gym roof and scoreboards at DeSales University in Upper Saucon Township.
A line of severe thunderstorms tore down trees and wires in several locations throughout Delaware County. This included one downed tree that snapped a utility pole in Media.
A severe thunderstorm knocked down a very large tree within Washington Square Park.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2015Every state in 2015This day in weather historyThe tornado archive for Pennsylvania, 2015Warnings in Pennsylvania, July 2015
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: 592925, 592903, 592928, 592932, 592929, 592933, 592935, 592934, 593859.