Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 99, NWS Pittsburgh, PA
NWS Pittsburgh, PA issued this severe thunderstorm warning at Aug 10, 2009, 5:17 PM EDT for 5 counties in Pennsylvania. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 10, 2009, 5:17 PM EDT (21:17 UTC)
- Expired
- Aug 10, 2009, 6:00 PM EDT
- In force
- 43 min
- Issued by
- NWS Pittsburgh, PA
- Area
- Storm-based polygon
Counties Armstrong County, PA, Butler County, PA, Clarion County, PA, Forest County, PA, Venango County, PA
The radar
The Pittsburgh radar (KPBZ), 90 km from the middle of the area, began a volume at 21:20 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 10, 3:13 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 9.3 hours before the alert went out and 96 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1328 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 696 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 59 m²/s²
- 0-3 km storm-relative helicity
- 50 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 1.6
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Pittsburgh, PA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 10, 2:30 PM EDT, 2 hours 47 minutes earlier.
Area forecast discussion, Aug 10, 2:30 PM EDT, 2 hours 47 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 230 PM EDT MON AUG 10 2009 .SYNOPSIS... A SLOW MOVING COLD FRONT WILL CAUSE SHOWERS AND THUNDERSTORMS THROUGH TUESDAY. SOME OF THE STORMS MAY BECOME SEVERE LATER THIS AFTERNOON AND EVENING...WITH A POTENTIAL FOR DAMAGING WINDS AND HEAVY RAINFALL. DRY WEATHER WILL RETURN BY MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... SCATTERED THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG AXIS OF WEAK MOISTURE CONVERGENCE...RUNNING FROM SOUTHERN PART OF CWA SOUTHWEST ACROSS PARTS OF NORTHERN WV. THESE STORMS WILL CONTINUE TO PUSH NORTHEAST ALONG AN AXIS JUST SOUTH AND EAST OF PITTSBURGH BUT SHOULD REMAIN LESS THAN SEVERE. STRONGER THUNDERSTORMS ARE BEGINNING TO DEVELOP ACROSS LAKE ERIE AND NW PA ALONG AN AXIS OF STRONGER CONVERGENCE AND VERY UNSTABLE AIR AHEAD OF A SLOW MOVING COLD FRONT.THIS AREA IS CURRENTLY PRIMED FOR DEVELOPMENT AS THE AFTERNOON PROGRESSES...AND COULD BECOME THE FOCUS FOR SEVERE STORMS LATER THIS AFTERNOON THROUGH THIS EVENING. THE GREATEST THREAT FROM SEVERE STORMS WILL BE WIND DAMAGE...BUT ABUNDANT MOISTURE WILL ALSO FAVOR HEAVY LOCAL RAINS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... STRONGEST STORMS SHOULD DIMINISH AFTER SUNSET BUT A THREAT OF SHOWERS WILL CONTINUE OVERNIGHT AS ANOTHER SHORTWAVE MOVES ACROSS THE AREA IN ASSOCIATION WITH THE SLOW MOVING FRONT. ADDITIONAL STRONG STORMS ARE POSSIBLE ON TUESDAY BEFORE THE FRONT FINALLY CLEARS THE AREA LATE TUESDAY. DRY WEATHER WILL RETURN TO THE REGION TUESDAY NIGHT AS THE FRONT MOVES EASTWARD TO THE MID ATLANTIC STATES. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... MODELS ARE IN AGREEMENT WITH A FORECAST OF DRY AND WARM WEATHER FROM MID WEEK THROUGH THE WEEKEND. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... AREA OF THUNDERSTORMS MOVING ACROSS SOUTHERN THIRD OF CWA THIS AFTERNOON IN ASSOCIATION WITH H5 SHORTWAVE. ONLY TERMINAL LIKELY TO BE AFFECTED IS MGW WITH CHANCE OF THUNDERSTORMS FROM 19-21Z. A STRONGER LINE OF CONVECTION DEVELOPING IN LAKE ERIE AHEAD OF APPROACHING COLD FRONT. EXPECT THIS TO MOVE SOUTHEAST ACROSS CWA THIS EVENING BETWEEN 10/22Z-11/03Z. THUNDERSTORMS SHOULD BE DISSIPATING BY MIDNIGHT WITH STRATUS AND FOG FORECAST FORMING LATE TONIGHT. EXPECT FAIRLY WIDESPREAD IFR CONDITIONS IN FOG AROUND SUNRISE. COLD FRONT WILL BE LOCATED IN NORTHWEST PA AROUND DAYBREAK AND VCNTY OF PIT BY MID AFTERNOON. THUNDERSTORMS LIKELY TO FOR ACROSS SOUTHERN PA AND NORTHERN WV TUESDAY AFTERNOON. UPPER RIDGE BUILDS BACK OVER REGION FROM WEDNESDAY THROUGH FRIDAY WITH GENERALLY VFR CONDITIONS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. &&
Hazardous weather outlook, Aug 10, 5:11 PM EDT, 6 minutes before
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</html>In the hours before
Special weather statement, Aug 10, 2:27 PM EDT, 2 hours 50 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 227 PM EDT MON AUG 10 2009 WVZ012-021-022-101930- MARION WV-MONONGALIA WV-WETZEL WV- 227 PM EDT MON AUG 10 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... MARION...WETZEL AND MONONGALIA... AT 223 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM BLACKSVILLE TO 7 MILES WEST OF FOLSOM...OR ALONG A LINE EXTENDING FROM BLACKSVILLE TO 4 MILES SOUTH OF JACKSONBURG...MOVING EAST AT 30 MPH. THE STORMS MAY PRODUCE SMALL HAIL...GUSTY WINDS AND BRIEF HEAVY RAINS KEEP AN EYE TO THE SKY AND MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.
Special weather statement, Aug 10, 2:43 PM EDT, 2 hours 34 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 243 PM EDT MON AUG 10 2009 PAZ032-101945- FAYETTE PA- 243 PM EDT MON AUG 10 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTY... FAYETTE... AT 240 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED STRONG THUNDERSTORMS 4 MILES SOUTH OF MASONTOWN...OR ABOUT OVER GREENSBORO...MOVING EAST AT 32 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... MASONTOWN... HOPWOOD... ELLIOTTSVILLE... CHALKHILL... FARMINGTON... OHIOPYLE... THESE THUNDERSTORMS MAY PRODUCE WIND GUSTS TO 35 MPH...PEA SIZE HAIL AND BRIEF HEAVY RAINS. KEEP AN EYE TO THE SKY AND MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.
Special weather statement, Aug 10, 3:33 PM EDT, 1 hour 44 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 333 PM EDT MON AUG 10 2009 MDZ001-PAZ032-WVZ021>023-102030- FAYETTE PA-GARRETT MD-MARION WV-MONONGALIA WV-PRESTON WV- 333 PM EDT MON AUG 10 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... GARRETT...FAYETTE...MARION...PRESTON AND MONONGALIA... AT 331 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 2 MILES NORTHEAST OF CLIFTON MILLS TO 3 MILES SOUTHWEST OF BENTONS FERRY... MOVING EAST AT 23 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... WINFIELD... LAUREL RUN... FAIRMONT... DELLSLOW... COLFAX... CLIFTON MILLS... BENTONS FERRY... BRUCETON MILLS... BROWNS CHAPEL... MASONTOWN... VALLEY FALLS... MARKLEYSBURG... THESE STORMS WILL LIKELY PRODUCE WIND GUSTS TO 40 MPH...INTENSE AND FREQUENT LIGHTNING...AND VERY HEAVY RAIN. KEEP AN EYE TO THE SKY AND MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. PRECAUTIONARY/PREPAREDNESS ACTIONS... INTENSE LIGHTNING IS OCCURING WITH THESE STORMS. IF OUTDOORS...STAY AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES. $$ A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM EDT MONDAY EVENING FOR EAST CENTRAL OHIO AND NORTHWESTERN PENNSYLVANIA. &&
Special weather statement, Aug 10, 4:06 PM EDT, 1 hour 11 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 406 PM EDT MON AUG 10 2009 OHZ040-041-PAZ007-008-013-102100- CARROLL OH-COLUMBIANA OH-LAWRENCE PA-MERCER PA-VENANGO PA- 406 PM EDT MON AUG 10 2009 ...THUNDERSTORMS... STRONG THUNDERSTORMS WILL MOVE THROUGH THE FOLLOWING COUNTIES...COLUMBIANA...CARROLL...VENANGO...MERCER AND LAWRENCE... AT 359 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 23 MILES NORTH OF MAURICE K GODDARD STATE PARK TO 35 MILES WEST OF HOMEWORTH...OR ALONG A LINE EXTENDING FROM 23 MILES NORTH OF MAURICE K GODDARD STATE PARK TO 15 MILES NORTHWEST OF STRASBURG...MOVING EAST AT 26 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... SHARON...SALEM...HERMITAGE... THESE STORMS WILL LIKELY PRODUCE STRONG WIND GUSTS TO 50 MPH...INTENSE AND FREQUEST LIGHTNING...AND VERY HEAVY RAIN. SOME OF THESE STORMS COULD BECOME SEVERE AND WARNINGS MAY NEED TO BE ISSUED AS THEY GET CLOSER. KEEP AN EYE TO THE SKY AND MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. PRECAUTIONARY/PREPAREDNESS ACTIONS... INTENSE LIGHTNING CAN BE EXPECTED WITH THESE STORMS. IF OUTDOORS...STAY AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES. $$ A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM EDT MONDAY EVENING FOR EAST CENTRAL OHIO AND NORTHWESTERN PENNSYLVANIA. &&
Special weather statement, Aug 10, 5:16 PM EDT, 1 minute before
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</html>The office that day
Everything else NWS Pittsburgh, PA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 4:27 PM EDT | Severe Thunderstorm Warning | PBZ | Mercer | 63 min |
| Aug 10, 4:47 PM EDT | Severe Thunderstorm Warning | PBZ | Venango | 58 min |
| Aug 10, 4:53 PM EDT | Severe Thunderstorm Warning | PBZ | Lawrence, Mercer | 37 min |
| Aug 10, 7:28 PM EDT | Areal Flood Advisory | PBZ | Allegheny | 3 hr |
| Aug 10, 7:52 PM EDT | Areal Flood Advisory | PBZ | Indiana | 3 hr |
| Aug 10, 4:45 PM EDT | Severe Thunderstorm Warning | PBZ | Carroll, Columbiana, Tuscarawas | 45 min |
| Aug 10, 5:42 PM EDT | Severe Thunderstorm Warning | PBZ | Carroll, Harrison, Jefferson | 43 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2009Every severe thunderstorm warning in 2009
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.