Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 207, NWS Pittsburgh, PA

August 21, 2011Butler County, Lawrence County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Aug 21, 2011, 1:55 PM EDT for Butler County, Lawrence County, Pennsylvania. It was in force for 35 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 21, 2011, 1:55 PM EDT (17:55 UTC)
Expired: Aug 21, 2011, 2:30 PM EDT
In force: 35 min
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon

Counties Butler County, PA, Lawrence County, PA

The radar

The Pittsburgh radar (KPBZ), 47 km from the middle of the area, began a volume at 17:58 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 12:00Z, 5.9 hours before the alert went out and 60 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: 1507 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 857 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.7

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 Aug 21, 1:37 PM EDT, 18 minutes earlier.

Area forecast discussion, Aug 21, 1:37 PM EDT, 18 minutes before

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Hazardous weather outlook, Aug 21, 11:03 AM EDT, 2 hours 52 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
1103 AM EDT SUN AUG 21 2011

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021>023-041-221515-
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-
1103 AM EDT SUN AUG 21 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.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY. THE PRIMARY
SEVERE THREAT WILL BE DAMAGING THUNDERSTORM WINDS AND HAIL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

NO HAZARDOUS IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED.

In the hours before

Special weather statement, Aug 21, 8:33 AM EDT, 5 hours 22 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
833 AM EDT SUN AUG 21 2011

OHZ068-069-WVZ012-211330-
MONROE OH-NOBLE OH-WETZEL WV-
833 AM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN NOBLE...SOUTHERN
MONROE AND WESTERN WETZEL COUNTIES...

AT 831 AM EDT...A STRONG THUNDERSTORM WAS LOCATED 5 MILES SOUTH OF
HARRIETTSVILLE...MOVING EAST AT 25 MPH.

WIND GUSTS TO 40 MPH AND HAIL UP TO DIME SIZE ARE POSSIBLE WITH THIS
STORM.

SOME LOCATIONS THAT WILL BE IMPACTED INCLUDE...
  HARRIETTSVILLE...     GRAYSVILLE...         ANTIOCH...
  FLY...                HANNIBAL...           WILEYVILLE...
  PORTERS FALLS...      PINE GROVE...         NEW MARTINSVILLE...

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

LAT...LON 3959 8086 3958 8089 3960 8095 3954 8104
      3957 8105 3957 8126 3960 8128 3959 8129
      3959 8139 3963 8143 3963 8146 3970 8148
      3967 8067 3947 8068 3947 8071

Special weather statement, Aug 21, 12:42 PM EDT, 1 hour 13 minutes before

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Special weather statement, Aug 21, 1:33 PM EDT, 22 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
133 PM EDT SUN AUG 21 2011

OHZ041-211800-
COLUMBIANA OH-
133 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN COLUMBIANA COUNTY...

AT 128 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 3 MILES WEST OF
GUILFORD LAKE STATE PARK...MOVING EAST AT 30 MPH.

WIND GUSTS TO 40 MPH AND PEA-SIZED HAIL ARE POSSIBLE WITH THIS STORM.

SOME LOCATIONS THAT WILL BE IMPACTED INCLUDE...
  GUILFORD LAKE STATE PARK...                 SALEM...
  LEETONIA...           LISBON...             COLUMBIANA...
  EAST PALESTINE...     BEAVER CREEK STATE PARK...

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

LAT...LON 4091 8081 4091 8079 4090 8078 4090 8054
      4069 8054 4077 8103 4091 8100 4091 8082

WOODRUM

Special weather statement, Aug 21, 1:47 PM EDT, 8 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
147 PM EDT SUN AUG 21 2011

PAZ013-014-211830-
BUTLER PA-LAWRENCE PA-
147 PM EDT SUN AUG 21 2011

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL BUTLER AND CENTRAL
LAWRENCE COUNTIES...

AT 145 PM EDT...A STRONG THUNDERSTORM WAS LOCATED NEW CASTLE...MOVING
EAST AT 25 MPH.

WIND GUSTS TO 40 MPH AND PEA-SIZED HAIL ARE POSSIBLE WITH THIS STORM.

SOME LOCATIONS THAT WILL BE IMPACTED INCLUDE...
  NEW CASTLE...         HARLANSBURG...        MCCONNELLS MILL...
  MORAINE STATE PARK... SLIPPERY ROCK...      BUTLER...

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

LAT...LON 4110 7987 4086 7987 4092 8040 4106 8038
      4108 8011 4107 8009 4108 8008

WOODRUM

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 4:19 AM EDT	Special Weather Statement	PBZ	Forest	56 min
Aug 21, 4:25 AM EDT	Special Weather Statement	PBZ	Lawrence	50 min
Aug 21, 5:39 AM EDT	Special Weather Statement	PBZ	Butler	66 min
Aug 21, 5:42 AM EDT	Special Weather Statement	PBZ	Forest	63 min
Aug 21, 7:42 AM EDT	Special Weather Statement	PBZ	Venango	63 min
Aug 21, 12:42 PM EDT	Special Weather Statement	PBZ	Armstrong	48 min
Aug 21, 1:47 PM EDT	Special Weather Statement	PBZ	Butler, Lawrence	43 min
Aug 21, 2:28 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler	33 min
Aug 21, 2:45 PM EDT	Special Weather Statement	PBZ	Beaver	45 min
Aug 21, 3:26 PM EDT	Special Weather Statement	PBZ	Allegheny, Beaver	49 min
Aug 21, 3:46 PM EDT	Special Weather Statement	PBZ	Westmoreland	44 min
Aug 21, 4:13 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Indiana, Westmoreland	62 min
Aug 21, 4:33 PM EDT	Special Weather Statement	PBZ	Greene	57 min
Aug 21, 3:52 AM EDT	Special Weather Statement	PBZ	Columbiana	38 min
Aug 21, 8:33 AM EDT	Special Weather Statement	PBZ	Monroe	57 min
Aug 21, 1:33 PM EDT	Special Weather Statement	PBZ	Columbiana	27 min
Aug 21, 2:17 PM EDT	Special Weather Statement	PBZ	Carroll, Tuscarawas	28 min
Aug 21, 2:43 PM EDT	Special Weather Statement	PBZ	Monroe, Noble	47 min
Aug 21, 3:09 PM EDT	Special Weather Statement	PBZ	Harrison	51 min
Aug 21, 4:02 PM EDT	Special Weather Statement	PBZ	Belmont	43 min
Aug 21, 2:59 PM EDT	Special Weather Statement	PBZ	Hancock	61 min
Aug 21, 3:51 PM EDT	Special Weather Statement	PBZ	Ohio	39 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.