An upper level disturbance combined with a very moist and unstable air mass to promote severe thunderstorms during the late afternoon and evening over the middle and lower Susquehanna Valley. The storms mainly produced damaging winds with only a few isolated reports of large hail.
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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.
An upper level disturbance combined with a very moist and unstable air mass to promote severe thunderstorms during the late afternoon and evening over the middle and lower Susquehanna Valley. The storms mainly produced damaging winds with only a few isolated reports of large hail.
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 Jul 12, 1:18 PM EST, 12 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 218 PM EDT MON JUL 12 2010 .SYNOPSIS... A APPROACHING STORM SYSTEM OVER THE LOWER GREAT LAKES WILL BRING AN INCREASE IN CLOUDS...HUMIDITY AND SHOWERS TO THE REGION THROUGH TUESDAY. A RIDGE OF HIGH PRESSURE WILL BRING A PERIOD OF DRY AND SLIGHTLY LESS HUMID CONDITIONS FOR WEDNESDAY AFTERNOON THROUGH MUCH OF THURSDAY BEFORE ANOTHER COLD FRONT BRINGS ANOTHER CHANCE OF SHOWERS LATER FRIDAY AND SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... WATER VAPOR IMAGES SHOW A VIRTUAL LINE UP OF FAST MOVING DISTURBANCES FROM THE EASTERN ROCKIES TO THE OHIO VALLEY. FIRST OF THE SHOWERS IS ENTERING THE REGION NOW AND SHOULD CONTINUE INTO THE OVERNIGHT. SHORT RANGE OPERATIONAL MODELS ARE HAVING A TOUGH TIME INITIALIZING THIS LEADING CONVECTION...WHICH LEADS TO A LOWER CONFIDENCE IN THE PLACEMENT OF THE HEAVIEST RAINS. GFS TRACKS ITS BEST CORE OF RAIN OFF THU FAR SERN PA AND NJ WHERE THE NAM TAKES ITS TIME ORGANIZING THE PRECIP BEFORE TRACKING A SLUG OF HEAVY RAIN UP THRU MY SERN ZONES BETWEEN 6 AND 12Z TONIGHT. FOLLOWED A BLEND OF SREF AND MOS POPS WITH THE BELIEF THAT MOST AREAS ARE LIKELY TO SEE MEASURABLE RAINS. SREF PLUMES SHOW MEAN PRECIP RANGING FROM ABOUT 1/3 INCH OVER THE NW TO ABOUT 1.25" OVER FAR SERN AREAS...BUT EXAMINING THE PLOTS SHOWS A HUGE SPREAD IN SOLUTIONS SO ITS EVIDENT THE ENSEMBLES ARE HAVING A HARD TIME WITH THE SITUATION. WHAT SEEMS TO BE AGREED UPON IS A 30-40KT SOUTHERLY LOW LEVEL JET THAT THE MODELS SCOOT UP THRU CENTRAL AND EASTERN PA TONIGHT. THE GFS IS FASTER THAN THE NAM/GEFS/SREF OUTPUT. SO LEANING TWD THE NAM/SREF/ECMWF AND ENSEMBLES...SUGGESTS THE RAIN CONTINUES TO PUSH THRU THE AREA FOR THE REMAINDER OF THE DAY...WITH ADDITIONAL RAINS DEVELOPING AS THE NOSE OF THE LOW LEVEL JET PUSHES INTO THE REGION TONIGHT. IT WILL GET MUGGIER AS WE ANOTHER THE EVENING AND OVERNIGHT WITH DEWPOINTS WELL INTO THE 60S TO NEAR 70 EXPECTED BY WED MORNING. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... WEAK TROFFING ALOFT WILL TEND TO KEEP US UNSETTLED THROUGH THE DAY TUES INTO TUES NIGHT...BEFORE THE SYSTEM PASSES TO OUR EAST AND ALLOWS FOR SOME DRYING LATER AT NIGHT TWD WED MORNING. TUES LOOKS SHOWERY WITH A CHANCE OF SOME THUNDER. I DIDN'T GET FANCY WITH THE TUES NIGHT POPS BEING SO FAR OUT IN TIME...BUT IF CURRENT PROJECTIONS HOLD THE BEST CHANCE OF RAIN WILL BE BEFORE MIDNIGHT...DWINDLING WITH TIME THEREAFTER. HIGHS TUES WILL BE CLOSE TO OR JUST BELOW SEASONAL NORMS WITH THE SHOWERS AND CLOUD COVER...WHILE OVERNIGHT LOWS WILL NOT FALL BACK MUCH...ENDING UP AVERAGING WELL ABOVE NORMAL. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... MODELS HAVE TRENDED DRIER FOR THE WEDNESDAY LATE MORNING...THROUGH THURSDAY PERIOD COMPARED TO 24 HOURS AGO. ASIDE FROM SOME AREAS OF LOW 20-30 POPS /MAINLY NEAR THE LAKE ERIE BREEZE OR AS A RESULT OF OROGRAPHIC EFFECTS/ CONDITIONS WILL BE GENERALLY PARTLY CLOUDY. THE SECOND HALF OF THIS WEEK WILL FEATURE THE WARMEST TEMPS...LIKELY 5-7 DEG F ABOVE NORMAL FOR MAXS AND MINS. OUR PEAK IN TEMPS WILL LIKELY COME THURSDAY AND FRIDAY WHEN GEFS MEAN 850 TEMPS CLIMB TO +1-2 STANDARD DEVIATIONS...OR 18-20C. FCST MAXS THURSDAY /IN THE MID 80S TO LOWER 90S/ COULD TURN OUT TO BE 2-4 DEG F ON THE LOWE SIDE. 500 MB HEIGHTS NEAR 592 DAM THURSDAY... COMBINED WITH A WESTERLY LLVL FLOW AND ABUNDANT...HAZY SUNSHINE COULD YIELD MAXS IN THE MID/UPPER 90S ACROSS THE LOWER SUSQ VALLEY...WITH UPPER 80S EVEN IN THE MTNS. A COLD FRONT WILL CROSS THE STATE LATER FRIDAY AND FRI NIGHT WITH SCATTERED SHOWERS AND TSRA...FOLLOWED BY AT LEAST A BRIEF BREAK TO THE HEAT AND HUMIDITY. A RESURGENCE OF MOISTURE IN RETURN UPPER FLOW AND WEAK UPPER TROFFING WILL PRODUCE DIURNALLY FORCED CONVECTION FOR SATURDAY AND SUNDAY. GFS AND ECMWF BOTH DEVELOP A MODERATE NORTHWEST FLOW WITH THE PASSAGE OF THE MEAN 5H TROF ON MONDAY...AS THE UPPER RIDGE AMPLIFIES OUT WEST. THIS WOULD SUGGEST SEASONABLY WARM CONDITIONS WITH BELOW NORMAL HUMIDITY ACROSS THE REGION FOR THE EARLY TO MIDDLE PORTION OF NEXT WEEK. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... INCREASINGLY HUMID AND UNSETTLED WEATHER WILL MOVE IN TODAY FROM THE WEST. THROUGH 06Z TUE THOUGH...CONDITIONS WILL REMAIN PRIMARILY VFR. AS SOUTHERLY FLOW DEVELOPS DURING THE DAY /AND SFC WINDS INCREASE TO AROUND 10 KTS/...MOISTURE WILL INCREASE BRINGING AN INCREASE IN CU FIELD ACROSS THE WEST. AIRMASS BECOMES INCREASINGLY UNSTABLE LATER THIS AFTERNOON AND EXPECT SCATTERED TSTMS TO DEVELOP IN WESTERN HALF OF PA LATE AFT/EVE. ADDED VCTS AND CB TO WESTERN TAFS DURING THAT TIME...BUT KEPT CIGS VFR EXCEPT FOR A TEMPO MVFR GROUP AT KJST. AFTER 06Z TUE...SCT CONVECTION POSS STATEWIDE WITH EXPANDING AREA OF MVFR CIGS. OUTLOOK... TUE...AREAS MVFR LIKELY IN SHRA/TSRA. WED...PRIMARILY VFR WITH SCT MVFR POSS IN SHRA/TSRA. THU...VFR. FRI...MAINLY VFR...BUT MVFR POSS IN SHRA/TSRA LATE. && .EQUIPMENT... A NEW TEMPERATURE SENSOR FOR SEG HAS BEEN ORDERED. IT IS EVIDENT THE CURRENT READINGS ARE SEVERAL DEGREES TOO HIGH. NO ESTIMATE YET ON WHEN THE UNIT WILL ARRIVE AND BE INSTALLED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...RXR EQUIPMENT...LA CORTE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 711 AM EDT MON JUL 12 2010 PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066-131015- 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- 711 AM EDT MON JUL 12 2010 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...TUESDAY THROUGH SUNDAY. SLOW MOVING...STRONG TO POSSIBLY SEVERE THUNDERSTORMS WILL BE SCATTERED ACROSS THE REGION TUESDAY INTO TUESDAY EVENING... ESPECIALLY ACROSS THE EASTERN HALF OF THE STATE. THE STORMS WILL BRING THE POTENTIAL FOR BRIEF...STRONG WIND GUSTS AND HAIL. ADDITIONALLY...LOCALLY VERY HEAVY RAIN UP TO 3 INCHES COULD LEAD TO FLOODING OF POOR DRAINAGE AREAS AND SOME SMALLER STREAMS DURING THIS PERIOD. A COLD FRONT WILL PUSH SOUTHEAST ACROSS PENNSYLVANIA LATER FRIDAY INTO SATURDAY...ACCOMPANIED BY SCATTERED STRONG TO POSSIBLY SEVERE THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE REQUESTED TO RELAY REPORTS OF HEAVY RAIN IN EXCESS OF ONE INCH...ANY FLOODING...AND WIND DAMAGE OR HAIL TO THE NATIONAL WEATHER SERVICE. LAMBERT/LA CORTE
The State College radar (KCCX), 99 km away, was scanning. The volume nearest the first event began at 18:30 UTC.
14 thunderstorm wind, 2 hail. Local standard time, as filed.
Thunderstorm winds estimated near 60 mph knocked down trees on Fox Hollow Road just south of Shermans Dale.
Thunderstorm winds estimated near 60 mph knocked down trees and wires in Mount Pleasant Hills.
Thunderstorm winds estimated near 60 mph knocked down trees in New Cumberland.
Thunderstorm winds estimated near 60 mph knocked down trees in New Columbia.
Thunderstorm winds estimated near 60 mph knocked down trees and wires in Columbia.
Thunderstorm winds estimated near 60 mph knocked down trees near Pillow.
Thunderstorm winds estimated near 60 mph knocked down trees and wires near Herndon.
Thunderstorm winds estimated near 60 mph knocked down trees in Rebuck.
Thunderstorm winds estimated near 60 mph knocked down trees and wires in Manheim.
Thunderstorm winds estimated near 60 mph knocked down several trees in South Lebanon Township.
Thunderstorm winds estimated near 60 mph knocked down trees and wires in Paradise Township.
Thunderstorm winds estimated near 60 mph knocked down trees and wires in Salisbury Township southeast of New Holland.
Thunderstorm winds estimated near 60 mph knocked down trees and wires in Pine Grove.
Thunderstorm winds estimated near 60 mph knocked down trees in Washington Township east of Pine Grove.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2010Every state in 2010This day in weather historyWarnings in Pennsylvania, July 2010
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: 232741, 232736, 232742, 232743, 232772, 232778, 232798, 232783, 232793, 232796, 232801, 232795, 232805, 232802, 232803, 232808.