Isolated severe thunderstorms produced sporadic wind damage in extreme southeastern Adams and southwestern York Counties during the evening.
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 CTP wrote it up.
Isolated severe thunderstorms produced sporadic wind damage in extreme southeastern Adams and southwestern York Counties during the evening.
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 State College, PA wrote its last area forecast discussion before the first event at Sep 1, 3:17 PM EST, 2 hours 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 417 PM EDT SAT SEP 1 2012 .SYNOPSIS... A WEAKENING COLD FRONT WILL STALL OUT ACROSS THE SOUTHERN TIER OF THE STATE INTO EARLY NEXT WEEK. THE REMNANTS OF HURRICANE ISAAC WILL TRACK EASTWARD ALONG THIS FRONTAL BOUNDARY INTO THE OHIO VALLEY AND TRACK ACROSS PENNSYLVANIA BY MID WEEK. THE HIGHEST CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE LATER MONDAY INTO WEDNESDAY. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... SHOWERS AND STORMS FORMING ACROSS THE SW...AND TRACKING SE. GIVEN VERY HUMID AIR MASS TO THE SOUTH AND WEST OF CENTRAL PA...EXPECT THIS ACTIVITY TO EXPAND A BIT BUT STAY FOCUSED IN THE SW ALONG AIR MASS BOUNDARY. THUS HAVE CONTINUED TO BUMP UP POPS IN THE LAURELS AND SC MTNS FOR THIS EVENING. && .SHORT TERM /MIDNIGHT THROUGH 6 PM SUNDAY/... DID LOWER POPS SOME LATER TONIGHT...AS TEMPS COOL AND AIR MASS BECOMES MORE STABLE. ALSO DID UP TEMPS SOME TONIGHT...MAINLY ACROSS THE SOUTH... GIVEN TYPE OF AIR MASS...AND EXPECTED CLD COVER. TEMPS ACROSS SOUTHERN PA STAYED WELL INTO THE 60S AND LOWER 70S LAST NIGHT. FOR SUNDAY...DID ADJUST POPS SOME. ALSO UP TEMPS SOME...GIVEN TYPE OF AIRMASS WE HAVE IN PLACE AND NEARBY. GFS HINTS THAT LOWEST QPF ACROSS CENTRAL AND NORTHERN PA... HIGHER POPS ACROSS THE SW AND SE...DID NOT WANT TO GO TOO HIGH WITH POPS. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... BROAD CONSENSUS AMONG MDL DATA THAT REMNANTS OF ISAAC WILL MERGE WITH QUASI-STATIONARY FRONT OVER PA LATE MONDAY AND TUESDAY...PRODUCING A WIDESPREAD MODERATE TO LOCALLY HVY RAINFALL. HAVE INCREASED POPS TO ARND 70 PCT MON NIGHT AND TUESDAY...WHEN GEFS 8H MFLUX VALUES SURGE TO NR +2SD WITH PASSAGE OF ISAAC REMNANTS. CURRENT GEFS MEAN 48HR RAINFALL ENDING TUE NIGHT RANGES FROM BTWN 1 TO 1.5 INCHES ACROSS CENTRAL PA. HOWEVER...INDIVIDUAL ENS MEMBERS AND OPER MDL RUNS SUGGEST LOCALIZED AMTS BTWN 2-3 INCHES POSSIBLE. USED MOS GUIDANCE TO NARROW DOWN THE TIMING FOR HIGH QPF. A QUICK LOOK AT FLASH FLOOD GUIDANCE SHOWS MOST OF CENTRAL PA CAN HANDLE UP TO 4 INCHES OF RAIN WITHIN A 6HR PERIOD BEFORE ANY SIG FLOODING. AS THE REMNANTS OF ISSAC ARE ABSORBED IN THE UPPER TROUGH...THERE REMAINS HIGHER PWATS AND BL MOISTURE THROUGH WEDNESDAY INTO THURSDAY. PA WILL REMAIN IN A WARM...UNSTABLE REGIME ON THE EAST SIDE OF DIGGING TROUGH OVR THE GRT LKS. GIVEN THE AMPLE MOISTURE AND THE INSTABILITY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS REMAIN POSSIBLE THROUGH THIS PERIOD. THIS IS ESPECIALLY TRUE ON THURSDAY AS MED RANGE GUIDANCE CURRENTLY BRINGS A WEAK COLD FRONT THRU THURSDAY. THE RETURN OF PARTIAL SUNSHINE SHOULD ALLOW DAYTIME TEMPS TO GET BACK INTO THE 80S WED BASED ON GEFS MEAN 8H TEMPS NR 16C. ZONAL FLOW WILL RETURN ALONG WITH THE ADVECTION OF DRIER AIR...LATE THURSDAY INTO FRIDAY. A FAIR AMT OF AGREEMENT THAT HIGH PRES ALONG WITH DRIER/COOLER AIR WILL BE ARRIVING LATE WEEK AND THROUGH THE WEEKEND. THE MODELS DO DISAGREE ON THE TIMING OF THE NEXT SYSTEM...WHICH COULD BE DUE LATE NEXT WEEKEND TO EARLY NEXT WEEK. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... SOME SHOWERS POSSIBLE AT JST. HAVE TO WATCH FOR THUNDER AND UPDATE AS NEEDED. PERHAPS A SHOWER INTO AOO. OTHERWISE...MAINLY HI CLDS ACROSS THE AREA...BEFORE SOME FOG AND HZ LATER TONIGHT. WINDS WILL BE ON THE LIGHT SIDE. GFS HAS HIGHEST QPF SW AND SE OF CENTRAL PA ON SUNDAY... THUS THINK MUCH OF THE DAY WILL BE DRY AND VFR CONDITIONS... AFTER THE FOG AND HZ BURNS OFF BY MID TO LATE MORNING. HIGHER CHC OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO WED...WITH LOWER CIGS ETC...AS THE REMAINS OF ISAAC TRACK EASTWARD ALONG THE STALLED FRONTAL BOUNDARY NEAR SOUTHERN PA. OUTLOOK... MON...SCT SHOWERS AND ISOLATED AFT TSRA. PERIODS OF LOW CIGS POSSIBLE...MAINLY LATE. TUE...SHOWERS LIKELY WITH SCT TSTMS. PERIODS OF LOW CIGS POSS. WED...SCT SHOWERS AND ISOLATED AFT TSRA. PERIODS OF LOW CIGS POSS. THU...IMPROVING CONDITIONS...AS WINDS SHIFT TO THE NW. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...MARTIN NEAR TERM...DANGELO/MARTIN SHORT TERM...MARTIN LONG TERM...FITZGERALD/CERU AVIATION...MARTIN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 638 AM EDT SAT SEP 1 2012 PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066-021045- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD- NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON-MIFFLIN- JUNIATA-SOMERSET-BEDFORD-FULTON-FRANKLIN-TIOGA-NORTHERN LYCOMING- SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR- NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND- ADAMS-YORK-LANCASTER- 638 AM EDT SAT SEP 1 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. 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 STATE COLLEGE PA
351 PM EDT SAT SEP 1 2012
PAZ024-033-012045-
CAMBRIA PA-SOMERSET PA-
351 PM EDT SAT SEP 1 2012
...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN SOMERSET AND
SOUTHWESTERN CAMBRIA COUNTIES...
AT 348 PM EDT...A STRONG THUNDERSTORM WAS NEAR NEW FLORENCE...MOVING
SOUTHEAST AT 10 MPH.
WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM. EXPECT INTENSE
LIGHTNING FROM THIS STORM. DO NOT STAY IN THE OPEN NOR SEEK SHELTER
UNDER TREES WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN A
THUNDERSTORM APPROACHES. VERY HEAVY RAIN WILL FALL FROM THIS STORM...
AND WILL CAUSE WATER TO POND ON ROADS AND FILL POOR DRAINAGE AREAS.
THE RAIN WILL CAUSE RAPID RISES ON SMALL STREAMS AND CREEKS. THIS
STORM WILL AFFECT WESTMONT...ELIM...TIRE HILL...JEROME AND BOSWELL.
THIS WILL IMPACT THE PENNSYLVANIA TURNPIKE BETWEEN MILE MARKERS 107
AND 116.
THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...THE JOHNSTOWN
EXPRESSWAY...ROUTE 30...ROUTE 219...STATE ROAD 56.
LAT...LON 3993 7908 4015 7917 4019 7913 4031 7905
4038 7898 4014 7871 4009 7873
FORECASTER: CERUSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
614 PM EDT SAT SEP 1 2012
PAZ064-012300-
ADAMS PA-
614 PM EDT SAT SEP 1 2012
...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN ADAMS COUNTY...
AT 611 PM EDT...A STRONG THUNDERSTORM WAS NEAR FAIRFIELD...MOVING
EAST AT 20 MPH.
WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.
THIS STORM WILL AFFECT GERMANTOWN...LITTLESTOWN AND MCSHERRYSTOWN.
THIS WILL IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 15...STATE ROAD
97.
LAT...LON 3977 7738 3979 7739 3982 7736 3981 7700
3976 7700 3971 7702 3972 7724
FORECASTER: DEVOIRThe Sterling radar (KLWX), 93 km away, was scanning. The volume nearest the first event began at 22:28 UTC.
3 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds estimated near 60 mph caused partial roof damage to a horse barn approximately 3 miles south of Gettysburg.
Thunderstorm winds estimated near 60 mph knocked down trees in Union Township near Littlestown.
Thunderstorm winds estimated near 60 mph knocked down several trees and produced minor structural damage to a few homes and sheds on Waterview Road. Two trees also fell on vehicles.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2012Every state in 2012This day in weather historyWarnings in Pennsylvania, September 2012
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: 397247, 397251, 397254.