Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 73, NWS Pittsburgh, PA

June 21, 2021Armstrong County, Clarion County, Jefferson County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Jun 21, 2021, 3:57 PM EDT for Armstrong County, Clarion County, Jefferson County, Pennsylvania. It was in force for 33 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jun 21, 2021, 3:57 PM EDT (19:57 UTC)
Expired: Jun 21, 2021, 4:30 PM EDT
In force: 33 min
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Armstrong County, PA, Clarion County, PA, Jefferson County, PA

The radar

The Pittsburgh radar (KPBZ), 102 km from the middle of the area, began a volume at 19:59 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.

What was reported inside it

Time	Report	Where	Remark
Jun 21, 4:00 PM EDT	TSTM WND DMG	Brookville, PA	TREE DOWN ON WATER PLANT RD.
Jun 21, 4:01 PM EDT	TSTM WND DMG	Limestone, PA	TREE DOWN
Jun 21, 4:10 PM EDT	TSTM WND DMG	2 N Roseville, PA	TREE DOWN ON ROSEVILLE SIGEL ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 21, 12:31 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 8.0 hours before the alert went out and 105 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: 931 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 988 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 260 m²/s²
0-3 km storm-relative helicity: 277 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.1

Open this sounding in Storm Lab

The text

As transmitted.

119 
WUUS51 KPBZ 211957
SVRPBZ
PAC005-031-065-212030-
/O.NEW.KPBZ.SV.W.0073.210621T1957Z-210621T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Pittsburgh PA
357 PM EDT Mon Jun 21 2021

The National Weather Service in Pittsburgh has issued a

* Severe Thunderstorm Warning for...
  Southwestern Jefferson County in west central Pennsylvania...
  Eastern Armstrong County in west central Pennsylvania...
  Southeastern Clarion County in west central Pennsylvania...

* Until 430 PM EDT.

* At 357 PM EDT, a severe thunderstorm was located near Clarion,
  moving east at 25 mph.

  HAZARD...Wind gusts to 60 mph.

  SOURCE...Radar.

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

* Locations impacted include...
  Clarion...                        Brookville...
  Strattanville...                  Summerville...
  Limestone...                      Hawthorn...
  Corsica...                        Worthville...
  Knox-Dale...                      

This includes Interstate 80 in Pennsylvania between mile markers 60
and 84.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter indoors and stay away from windows.

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

&&

LAT...LON 4106 7947 4124 7944 4124 7899 4097 7902
TIME...MOT...LOC 1957Z 274DEG 22KT 4114 7938 

HAIL...<.75IN
WIND...60MPH
 
$$

3 follow-up statements

281 
WWUS51 KPBZ 212006
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
406 PM EDT Mon Jun 21 2021

PAC005-031-065-212030-
/O.CON.KPBZ.SV.W.0073.000000T0000Z-210621T2030Z/
Jefferson PA-Armstrong PA-Clarion PA-
406 PM EDT Mon Jun 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR SOUTHWESTERN JEFFERSON...EASTERN ARMSTRONG AND SOUTHEASTERN
CLARION COUNTIES...

At 406 PM EDT, a severe thunderstorm was located near Clarion, moving
east at 35 mph.

HAZARD...Wind gusts to 60 mph.

SOURCE...Radar.

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

Locations impacted include...
Clarion...                        Brookville...
Strattanville...                  Summerville...
Limestone...                      Hawthorn...
Corsica...                        Worthville...
Knox-Dale...                      

This includes Interstate 80 in Pennsylvania between mile markers 63
and 84.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter indoors and stay away from windows.

Torrential rainfall is occurring with this storm and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

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

&&

LAT...LON 4105 7940 4124 7938 4124 7899 4097 7902
TIME...MOT...LOC 2006Z 271DEG 31KT 4116 7927 

HAIL...<.75IN
WIND...60MPH
 
$$

822 
WWUS51 KPBZ 212021 RRA
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
421 PM EDT Mon Jun 21 2021

PAC005-031-212031-
/O.CAN.KPBZ.SV.W.0073.000000T0000Z-210621T2030Z/
Armstrong PA-Clarion PA-
421 PM EDT Mon Jun 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN ARMSTRONG AND
SOUTHEASTERN CLARION COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area.

A Severe Thunderstorm Watch remains in effect until 800 PM EDT for
west central Pennsylvania.

LAT...LON 4105 7921 4124 7920 4124 7899 4108 7902
TIME...MOT...LOC 2021Z 259DEG 37KT 4119 7906 

$$

PAC065-212030-
/O.CON.KPBZ.SV.W.0073.000000T0000Z-210621T2030Z/
Jefferson PA-
421 PM EDT Mon Jun 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR WEST CENTRAL JEFFERSON COUNTY...

At 421 PM EDT, a severe thunderstorm was located over Brookville,
moving east at 45 mph.

HAZARD...Wind gusts to 60 mph.

SOURCE...Radar.

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

Locations impacted include...
Brookville...                     Summerville...
Corsica...                        Knox-Dale...

This includes Interstate 80 in Pennsylvania between mile markers 73
and 83.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter indoors and stay away from windows.

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

&&

LAT...LON 4105 7921 4124 7920 4124 7899 4108 7902
TIME...MOT...LOC 2021Z 259DEG 37KT 4119 7906 

HAIL...<.75IN
WIND...60MPH
 
$$

789 
WWUS51 KPBZ 212030
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
430 PM EDT Mon Jun 21 2021

PAC065-212039-
/O.EXP.KPBZ.SV.W.0073.000000T0000Z-210621T2030Z/
Jefferson PA-
430 PM EDT Mon Jun 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL JEFFERSON COUNTY
WILL EXPIRE AT 430 PM EDT...
                
The storm which prompted the warning has weakened below severe 
limits; therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 800 PM EDT for
west central Pennsylvania.

LAT...LON 4105 7921 4124 7920 4124 7899 4108 7902
TIME...MOT...LOC 2029Z 274DEG 22KT 4119 7900 

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 8:55 PM EDT	Special Weather Statement	PBZ	Armstrong	20 min
Jun 21, 7:27 AM EDT	Special Weather Statement	PBZ	Lawrence, Mercer	33 min
Jun 21, 1:57 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Lawrence	48 min
Jun 21, 2:08 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette	22 min
Jun 21, 2:15 PM EDT	Severe Thunderstorm Warning	PBZ	Mercer, Venango	30 min
Jun 21, 2:21 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Lawrence	24 min
Jun 21, 2:37 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Butler, Lawrence, Washington	23 min
Jun 21, 2:45 PM EDT	Severe Thunderstorm Warning	PBZ	Forest, Venango	30 min
Jun 21, 2:51 PM EDT	Tornado Warning	PBZ	Allegheny, Beaver, Butler	9 min
Jun 21, 2:55 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Beaver, Butler, Westmoreland	35 min
Jun 21, 2:58 PM EDT	Tornado Warning	PBZ	Allegheny, Butler	17 min
Jun 21, 3:00 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Washington	30 min
Jun 21, 3:21 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Butler, Indiana, Westmoreland	24 min
Jun 21, 3:25 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Westmoreland	35 min
Jun 21, 3:29 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	46 min
Jun 21, 3:37 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Indiana, Jefferson, Westmoreland	23 min
Jun 21, 3:45 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Indiana, Westmoreland	45 min
Jun 21, 3:47 PM EDT	Special Weather Statement	PBZ	Washington	28 min
Jun 21, 3:53 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Fayette, Greene, Washington, Westmoreland	37 min
Jun 21, 3:55 PM EDT	Areal Flood Advisory	PBZ	Allegheny, Westmoreland	111 min
Jun 21, 3:55 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Indiana, Westmoreland	35 min
Jun 21, 4:05 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Fayette, Washington, Westmoreland	25 min
Jun 21, 4:13 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana, Westmoreland	32 min
Jun 21, 4:18 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene, Washington, Westmoreland	27 min
Jun 21, 4:19 PM EDT	Severe Thunderstorm Warning	PBZ	Greene, Washington	41 min
Jun 21, 4:27 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana, Westmoreland	33 min
Jun 21, 4:28 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Westmoreland	32 min
Jun 21, 4:41 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene, Washington, Westmoreland	49 min
Jun 21, 4:43 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana, Westmoreland	32 min
Jun 21, 4:57 PM EDT	Severe Thunderstorm Warning	PBZ	Greene	29 min
Jun 21, 5:03 PM EDT	Tornado Warning	PBZ	Greene	6 min
Jun 21, 5:08 PM EDT	Areal Flood Advisory	PBZ	Fayette, Greene, Washington, Westmoreland	3 hr
Jun 21, 6:39 PM EDT	Areal Flood Advisory	PBZ	Allegheny, Greene, Washington, Westmoreland	2 hr
Jun 21, 6:43 PM EDT	Special Weather Statement	PBZ	Fayette	32 min
Jun 21, 7:23 PM EDT	Flash Flood Warning	PBZ	Allegheny, Fayette, Washington, Westmoreland	3 hr
Jun 21, 7:46 PM EDT	Areal Flood Warning	PBZ	Fayette, Greene, Washington, Westmoreland	3 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.