Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 293, NWS Pittsburgh, PA

August 29, 20214 counties in Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Aug 29, 2021, 3:52 PM EDT for 4 counties in Pennsylvania. It was in force for 23 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 29, 2021, 3:52 PM EDT (19:52 UTC)
Expired
Aug 29, 2021, 4:15 PM EDT
In force
23 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Butler County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA

The radar

The Pittsburgh radar (KPBZ), 61 km from the middle of the area, began a volume at 19:54 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, 7.9 hours before the alert went out and 73 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-pSkew-T log-p diagram, Pittsburgh, PA at 12:00Z on 2021-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 985 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Pittsburgh, PA at 12:00Z on 2021-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
985 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
957 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

014 
WUUS51 KPBZ 291952
SVRPBZ
PAC019-073-085-121-292015-
/O.NEW.KPBZ.SV.W.0293.210829T1952Z-210829T2015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Pittsburgh PA
352 PM EDT Sun Aug 29 2021

The National Weather Service in Pittsburgh has issued a

* Severe Thunderstorm Warning for...
  Southeastern Mercer County in northwestern Pennsylvania...
  Southwestern Venango County in northwestern Pennsylvania...
  Northeastern Lawrence County in western Pennsylvania...
  Northwestern Butler County in west central Pennsylvania...

* Until 415 PM EDT.

* At 352 PM EDT, a severe thunderstorm was located over Slippery
  Rock, or near Grove City, moving northeast at 25 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and power lines, resulting in some 
           power outages.

* Locations impacted include...
  Slippery Rock, Harrisville, Plain Grove Township, West Liberty,
  Barkeyville, and Boyers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Please report severe weather by calling 412-262-1988, posting to 
the NWS Pittsburgh Facebook page, or using Twitter @NWSPITTSBURGH. 

&&

LAT...LON 4099 8015 4110 8018 4121 7991 4102 7985
TIME...MOT...LOC 1952Z 245DEG 20KT 4107 8009 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$
2 follow-up statements
427 
WWUS51 KPBZ 292005
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
405 PM EDT Sun Aug 29 2021

PAC019-073-085-121-292015-
/O.CON.KPBZ.SV.W.0293.000000T0000Z-210829T2015Z/
Mercer PA-Venango PA-Lawrence PA-Butler PA-
405 PM EDT Sun Aug 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR SOUTHEASTERN MERCER...SOUTHWESTERN VENANGO...EASTERN LAWRENCE AND
NORTHWESTERN BUTLER COUNTIES...

At 405 PM EDT, a severe thunderstorm was located near Slippery Rock,
or near Grove City, moving northeast at 25 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and power lines, resulting in some 
         power outages.

Locations impacted include...
Grove City, Slippery Rock, Harrisville, Plain Grove Township, West
Liberty, Barkeyville, and Boyers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Please report severe weather by calling 412-262-1988, posting to 
the NWS Pittsburgh Facebook page, or using Twitter @NWSPITTSBURGH. 

&&

LAT...LON 4100 8009 4112 8014 4121 7991 4102 7985
TIME...MOT...LOC 2005Z 245DEG 20KT 4110 8000 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$
541 
WWUS51 KPBZ 292011
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
411 PM EDT Sun Aug 29 2021

PAC019-073-085-121-292021-
/O.EXP.KPBZ.SV.W.0293.000000T0000Z-210829T2015Z/
Mercer PA-Venango PA-Lawrence PA-Butler PA-
411 PM EDT Sun Aug 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MERCER...
SOUTHWESTERN VENANGO...EASTERN LAWRENCE AND NORTHWESTERN BUTLER
COUNTIES WILL EXPIRE AT 415 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

LAT...LON 4100 8009 4112 8014 4121 7991 4102 7985
TIME...MOT...LOC 2011Z 245DEG 20KT 4111 7998 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 29, 1:45 PM EDTSevere Thunderstorm WarningPBZForest, Venango15 min
Aug 29, 3:09 PM EDTSpecial Weather StatementPBZLawrence36 min
Aug 29, 3:17 PM EDTSevere Thunderstorm WarningPBZMercer28 min
Aug 29, 3:33 PM EDTSpecial Weather StatementPBZWashington27 min
Aug 29, 3:38 PM EDTSevere Thunderstorm WarningPBZBeaver37 min
Aug 29, 3:44 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Washington31 min
Aug 29, 3:57 PM EDTSpecial Weather StatementPBZBeaver48 min
Aug 29, 4:02 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Butler28 min
Aug 29, 4:06 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Butler, Washington24 min
Aug 29, 4:23 PM EDTSpecial Weather StatementPBZButler52 min
Aug 29, 4:28 PM EDTSevere Thunderstorm WarningPBZAllegheny, Butler32 min
Aug 29, 4:48 PM EDTSpecial Weather StatementPBZArmstrong27 min
Aug 29, 4:59 PM EDTSevere Thunderstorm WarningPBZAllegheny, Westmoreland31 min
Aug 29, 5:14 PM EDTSevere Thunderstorm WarningPBZAllegheny, Westmoreland31 min
Aug 29, 5:22 PM EDTSpecial Weather StatementPBZForest, Jefferson38 min
Aug 29, 6:03 PM EDTSpecial Weather StatementPBZIndiana27 min
Aug 29, 6:22 PM EDTAreal Flood AdvisoryPBZArmstrong, Indiana, Jefferson113 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021Every severe thunderstorm warning in 2021

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.