Slow moving thunderstorms produced heavy rain and isolated flash flooding in eastern Warren 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 CTP wrote it up.
Slow moving thunderstorms produced heavy rain and isolated flash flooding in eastern Warren County.
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 Aug 11, 2:47 PM EST, 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 347 PM EDT TUE AUG 11 2009 .SYNOPSIS... A COLD FRONT WILL PUSH THROUGH PENNSYLVANIA THIS EVENING...THEN STALL ALONG THE EAST COAST FOR THE REST OF THE WEEK. MEANWHILE... A RIDGE OF HIGH PRESSURE WILL WORK INTO THE NORTHWEST PART OF THE STATE. A CUT OFF UPPER LOW OVER THE SOUTHERN APPALACHIANS WILL LIKELY LIFT NORTHEAST TOWARD PENNSYLVANIA BY NEXT WEEKEND. THIS FEATURE WILL KEEP SOME CHC OF SHOWERS AND STORMS ALONG THE MARYLAND BORDER INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SFC COLD FRONT LOCATED NEAR A KELM TO KPBZ LINE CURRENTLY WITH A BAND OF MODERATE TO HEAVY RAIN AND SOME EMBEDDED THUNDER. SO FAR NO SIGNS OF BOWING. FORWARD MOTION OF LINE WAS INITIALLY SLOW... BUT IS PICKING UP SOME FORWARD SPEED AS THE BOUNDARY LAYER FLOW INCREASES TO 10-15 KNOTS AS PER NAM/GFS. MORNING STRATUS AND FOG HAS GIVEN WAY TO HAZY SUNSHINE IN MOST AREAS WITH MEAN CAPES GROWING INTO THE MODERATE RANGE. LACK OF SHEAR WOULD APPEAR TO PRECLUDE SEVERE...BUT GIVEN THESE CAPES AND WATER LOADING FROM 1.75+ PWS...CANNOT RULE OUT ISOLATED SEVERE FROM A BOWING LINE SEGMENT OR COLLAPSING CORE...PARTICULARLY OVER MY SOUTHEAST WHICH SHOULD FEATURE THE HIGHEST CAPES AND LAPSE RATES THIS AFTERNOON AND EVENING IN A BUILDING 925-850 MB THETA-E RIDGE...AS PER RUC13. WENT WITH HIGH CHANCE/LOW LIKELY POPS AS THE FRONT SAGS SOUTHEASTWARD THIS EVENING...AND GENERAL BROADBRUSH OF LOW TO MID CHANCE POPS AS THE REAL COOLING ALOFT ASSOCIATED WITH THE 500 MB TROF APPROACH OVERNIGHT TAKES PLACE. DRIER/CO0LER WX SHOULD GRADUALLY FILTER INTO THE REGION FROM THE WEST LATER TONIGHT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... AS SHORTWAVE ROTATES THRU THE REGION ON WED...STILL ENOUGH LL MOISTURE/INSTABILITY LIKELY TO REMAIN ACROSS THE AREA TO SUPPORT SOME CHC OF MAINLY AFTN CONVECTION. && .LONG TERM /THURSDAY THROUGH TUESDAY/... MODELS SLIGHTLY DIFFERENT EACH DAY WITH REGARD TO CUTOFF LOW. GIVEN TIME OF YEAR...LOCATION OF MTS...HARD TO SEE FRONT GOING VERY FAR TO THE SOUTH AND EAST. THUS WITH HINTS OF A CUTOFF OVER PA OR NEARBY...THINK THERE WILL BE A SLIGHT CHC TO CHC OF SHOWERS AND STORMS ACROSS THE REGION...MAINLY SOUTH OF INTERSTATE 80 EARLY ON...BUT ALL AREAS BY LATER NEXT MONDAY INTO TUE...AS NEXT COLD FRONT NEARS THE EAST COAST. TEMPS WILL BE CLOSE TO NORMAL. DID EDGE TEMPS DOWN A DEGREE OR SO DURING THE DAY...AND EDGE UP A DEGREE OR SO AT NIGHT... AS I AM LEANING ON THE WET AND CLDY SIDE OF THINGS. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... SCATTERED SHOWERS/TSTORMS WILL CROSS THE REGION THIS AFTERNOON AND EVENING...WITH MVFR RESTRICTIONS NEAR TSRA AND HEAVY DOWNPOURS. INVERSION WILL TRAP LOW LEVEL MOISTURE LATER TONIGH AND SPREAD MVFR/LIFR CIGS/VSBYS TO ALL BUT KMDT OVERNIGHT. ADDITIONAL SCATTERED SHOWERS/TSTORMS IN STORE FOR WED AFT...MAINLY IN SE HALF. OUTLOOK... WED...LIFR/MVFR EARLY IN FOG...THEN VFR WITH MVFR IN SCT TSTORMS. THU-FRI-SAT-SUN...VFR. ISOLD AFTN MVFR SHOWERS/TSTORMS MAINLY SE. && .HYDROLOGY... BEEN WATCHING CELLS ACROSS NW PA. SO FAR THINGS ARE MOVING...FEW SPOTS MAY HAVE SEEN ABOUT AN INCH OF RAIN SO FAR...ESTIMATED BY RADAR. WOULD EXPECT CELLS TO CONTINUE TO MOVE EAST AT 10 TO 15 MPH. FLOOD ADVISORY EARLIER...NOW A FLASH FLOOD WARNING. WILL CONTINUE TO MONITOR...AND ISSUE PRODUCTS AS NEEDED. AWAY FROM THIS NW AREA...FFG NOT SO LOW...THUS FLOODING SHOULD NOT BE A PROBLEM OUTSIDE THE FAR NW. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...DEVOIR NEAR TERM...DEVOIR SHORT TERM...MARTIN LONG TERM...MARTIN AVIATION...DEVOIR/RXR HYDROLOGY...MARTIN/DEVOIR/JUNG
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 1253 PM EDT TUE AUG 11 2009 PAZ004>006-010>012-017>019-024>028-033-034-037-041-042-045-046- 049>053-056>058-121700- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD- NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON-MIFFLIN- JUNIATA-SOMERSET-BEDFORD-TIOGA-NORTHERN LYCOMING-SULLIVAN- SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR- NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL- 1253 PM EDT TUE AUG 11 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AS A WEAK COLD FRONT ACTS ON VERY MOIST AND SOMEWHAT UNSTABLE AIR OVER THE REGION. SLOW MOVING STORMS WILL POSE A GREATER THREAT OF LOCALLY HEAVY RAINFALL OVER SOME AREAS...ESPECIALLY WHERE CELLS TRAIN OR TRACK OVER AREAS WHICH SAW HEAVY RAINFALL ON MONDAY. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. PAZ035-036-059-063>066-121700- FULTON-FRANKLIN-LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER- 1253 PM EDT TUE AUG 11 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. A SLOW MOVING COLD FRONT WILL PUSH ACROSS THE AREA THIS EVENING. SHOWERS AND SCATTERED THUNDERSTORMS WILL ACCOMPANY THE WEAK FRONT... AND MAY PRODUCE LOCALLY HEAVY DOWNPOURS AND SOME ISOLATED STRONG WIND GUSTS. LOCAL MINOR FLOODING IS A POSSIBILITY WITH STRONGER SLOW MOVING STORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. DEVOIR
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
310 PM EDT TUE AUG 11 2009
PAZ004-005-111945-
MCKEAN PA-WARREN PA-
310 PM EDT TUE AUG 11 2009
...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN WARREN AND
NORTHWESTERN MCKEAN COUNTIES...
AT 311 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 9 MILES NORTHEAST
OF WARREN...MOVING SOUTHEAST AT 15 MPH.
WIND GUSTS TO 40 MPH AND HAIL UP TO DIME SIZE ARE POSSIBLE WITH THIS
STORM.
THIS STORM WILL BE NEAR SCANDIA AROUND 320 PM AND KINZUA DAM AROUND
335 PM.
THIS WILL IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 62...STATE ROAD
59.
LAT...LON 4198 7867 4171 7890 4192 7921 4200 7915
4201 7880
EXPERIMENTAL
FORECASTER: JUNGSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
328 PM EDT TUE AUG 11 2009
PAZ010-017-112030-
CLEARFIELD PA-ELK PA-
328 PM EDT TUE AUG 11 2009
...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN CLEARFIELD AND
SOUTH CENTRAL ELK COUNTIES...
AT 327 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 9 MILES EAST OF
BROOKVILLE...MOVING SOUTHEAST AT 20 MPH.
WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM. 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 BE NEAR BROCKPORT AROUND 350 PM...DUBOIS AROUND 400
PM...ROCKTON AROUND 410 PM...S.B. ELLIOT STATE PARK AROUND 420 PM AND
HYDE AROUND 430 PM.
THIS WILL IMPACT I-80 BETWEEN MILE MARKERS 97 AND 118.
THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 119...ROUTE
219...ROUTE 322...STATE ROAD 153...STATE ROAD 255.
LAT...LON 4119 7879 4121 7877 4121 7872 4122 7872
4123 7875 4127 7875 4129 7880 4131 7878
4123 7831 4090 7848 4104 7881 4114 7881
EXPERIMENTAL
FORECASTER: DEVOIRThe Buffalo radar (KBUF), 127 km away, was scanning. The volume nearest the first event began at 19:58 UTC.
1 flash flood. Local standard time, as filed.
Thunderstorms produced heavy rain and flash flooding in Warren and Scandia. A number of roads were closed due to flooding. Reports of manhole covers being lifted off in the city of Warren were also received.
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, August 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: 179825.