Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 215, NWS Pittsburgh, PA

September 13, 2011Clarion County, Forest County, Jefferson County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Sep 13, 2011, 8:20 PM EDT for Clarion County, Forest County, Jefferson County, Pennsylvania. It was in force for 55 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: Sep 13, 2011, 8:20 PM EDT (00:20 UTC)
Expired: Sep 13, 2011, 9:15 PM EDT
In force: 55 min
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon

Counties Clarion County, PA, Forest County, PA, Jefferson County, PA

The radar

The State College radar (KCCX), 109 km from the middle of the area, began a volume at 00:23 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 nearest sounding before it

Pittsburgh, PA (KPIT), launched 00:00Z, 0.3 hours before the alert went out and 122 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 753 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 1290 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 150 m²/s²
0-3 km storm-relative helicity: 276 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.2

Open this sounding in Storm Lab

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 Sep 13, 7:24 PM EDT, 56 minutes earlier.

Area forecast discussion, Sep 13, 7:24 PM EDT, 56 minutes before

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Hazardous weather outlook, Sep 13, 4:24 AM EDT, 15 hours 56 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
424 AM EDT TUE SEP 13 2011

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021>023-041-140830-
GARRETT-TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-
JEFFERSON OH-MUSKINGUM-GUERNSEY-BELMONT-NOBLE-MONROE-MERCER-VENANGO-
FOREST-LAWRENCE-BUTLER-CLARION-JEFFERSON PA-BEAVER-ALLEGHENY-
ARMSTRONG-INDIANA-WASHINGTON-GREENE-WESTMORELAND-WESTMORELAND RIDGES-
FAYETTE-FAYETTE RIDGES-HANCOCK-BROOKE-OHIO-MARSHALL-WETZEL-MARION-
MONONGALIA-PRESTON-TUCKER-
424 AM EDT TUE SEP 13 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST
CENTRAL OHIO...NORTHWEST PENNSYLVANIA...SOUTHWEST
PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA...NORTHERN WEST VIRGINIA
AND NORTHERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

In the hours before

Special weather statement, Sep 13, 6:45 PM EDT, 1 hour 35 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
645 PM EDT TUE SEP 13 2011

PAZ007>009-132330-
FOREST PA-MERCER PA-VENANGO PA-
645 PM EDT TUE SEP 13 2011

...STRONG THUNDERSTORMS WILL AFFECT NORTHERN MERCER...NORTHERN
VENANGO AND NORTHWESTERN FOREST COUNTIES...

AT 643 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 13 MILES
NORTH OF PLEASANTVILLE TO 19 MILES NORTH OF ATWATER...MOVING EAST AT
30 MPH.

WIND GUSTS TO 40 MPH AND HAIL UP TO DIME SIZE ARE POSSIBLE WITH THESE
STORMS, ALONG WITH A SHORT PERIOD OF FREQUENT LIGHTNING.

DO NOT STAY IN THE OPEN NOR SEEK SHELTER UNDER TREES WHEN LIGHTNING
THREATENS...MOVE INDOORS WHEN A THUNDERSTORM APPROACHES.

SOME LOCATIONS THAT WILL BE IMPACTED INCLUDE...
  GREENVILLE...         PLEASANTVILLE...
  OIL CREEK STATE PARK...
  MAURICE K GODDARD STATE PARK...             COOPERSTOWN...

PLEASE REPORT SIGNIFICANT WEATHER TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...877-633-6772...WHEN YOU CAN DO SO SAFELY.

LAT...LON 4127 8052 4149 8052 4150 8001 4163 7982
      4163 7921

Special weather statement, Sep 13, 7:45 PM EDT, 35 minutes before

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The office that day

Everything else NWS Pittsburgh, PA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 13, 8:31 PM EDT	Severe Thunderstorm Warning	PBZ	Clarion, Mercer, Venango	59 min
Sep 13, 9:01 PM EDT	Special Weather Statement	PBZ	Mercer	29 min
Sep 13, 9:21 PM EDT	Special Weather Statement	PBZ	Jefferson	24 min
Sep 13, 9:33 PM EDT	Special Weather Statement	PBZ	Clarion	27 min
Sep 13, 10:05 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion, Jefferson	25 min
Sep 13, 10:35 PM EDT	Special Weather Statement	PBZ	Jefferson	25 min
Sep 13, 11:01 PM EDT	Special Weather Statement	PBZ	Armstrong, Clarion, Jefferson	59 min
Sep 14, 2:59 PM EDT	Special Weather Statement	PBZ	Fayette	46 min
Sep 14, 3:18 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette	42 min
Sep 14, 2:50 PM EDT	Special Weather Statement	PBZ	Marion, Preston	25 min
Sep 14, 2:53 PM EDT	Severe Thunderstorm Warning	PBZ	Marion, Monongalia, Preston	52 min
Sep 14, 3:50 PM EDT	Special Weather Statement	PBZ	Preston	40 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2011 Every severe thunderstorm warning in 2011

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.