Alert archive / Pennsylvania / Tornado Warnings in 2021

Tornado Warning 27, NWS Pittsburgh, PA

October 21, 2021Allegheny County, Beaver County, Westmoreland County, Pennsylvania

NWS Pittsburgh, PA issued this tornado warning at Oct 21, 2021, 7:40 PM EDT for Allegheny County, Beaver County, Westmoreland County, Pennsylvania. It was in force for 20 min. 8 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
Oct 21, 2021, 7:40 PM EDT (23:40 UTC)
Expired
Oct 21, 2021, 8:00 PM EDT
In force
20 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Allegheny County, PA, Beaver County, PA, Westmoreland County, PA

The radar

The Pittsburgh radar (KPBZ), 18 km from the middle of the area, began a volume at 23:40 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

TimeReportWhereRemark
Oct 21, 7:41 PM EDTTSTM WND DMG1 Nw Highcliff, PA*CORRECTED FOR EVENT TYPE** REPORT OF GLASS STORE FRONT BLOWN OFF AT TARGET. POSSIBLE TORNADO. TIME ESTIMTED BASED ON RADAR.
Oct 21, 7:41 PM EDTTORNADO1 Nw Highcliff, PAREPORT OF GLASS STORE FRONT BLOWN OFF AT TARGET. POSSIBLE TORNADO. TIME ESTIMTED BASED ON RADAR.
Oct 21, 7:42 PM EDTTORNADO1 Ese Mount Nebo, PASPOTTER REPORTED WEAK RAIN-WRAPPED TORNADO CROSSING I-279 SOUTH OF MILE MARKER 11.
Oct 21, 7:45 PM EDTTSTM WND DMGMccandless Township, PANUMEROUS TREE LIMBS DOWN
Oct 21, 7:49 PM EDTTORNADO1 Wnw Allison Park, PAROOF BLOWN OFF HOME ON LINDEN DR IN HAMPTON TWP.
Oct 21, 7:53 PM EDTTSTM WND DMG1 N Allison Park, PATREES AND POWER LINES DOWN, ROOF DAMAGE, TREE ON CAR WITH ENTRAPMENT IN HAMPTON TWP. POSSIBLE TORNADO.
Oct 21, 7:53 PM EDTTSTM WND DMG3 S Hampton Township, PANUMEROUS WIRES DOWN
Oct 21, 7:53 PM EDTTSTM WND DMGHampton Township, PAMULTIPLE TREES UPROOTED OR SNAPPED OFF. TREES ON HOUSES. POWER LINES DOWN. POSSIBLE TORNADO.

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

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 11.7 hours before the alert went out and 17 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 2021-10-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-10-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 105 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1175 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
105 m²/s²
0-3 km storm-relative helicity
188 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

612 
WFUS51 KPBZ 212340
TORPBZ
PAC003-007-129-220000-
/O.NEW.KPBZ.TO.W.0027.211021T2340Z-211022T0000Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Pittsburgh PA
740 PM EDT Thu Oct 21 2021

The National Weather Service in Pittsburgh has issued a

* Tornado Warning for...
  East central Beaver County in western Pennsylvania...
  Northeastern Allegheny County in southwestern Pennsylvania...
  Northwestern Westmoreland County in southwestern Pennsylvania...

* Until 800 PM EDT.
    
* At 740 PM EDT, a severe thunderstorm capable of producing a tornado
  was located over Franklin Park, moving east at 35 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Ross Township, Bellevue, West View and McKees Rocks around 745 PM 
  EDT.
  Pittsburgh, McCandless Township, Shaler Township and Gibsonia 
  around 750 PM EDT.
  Millvale, Etna and Sharpsburg around 755 PM EDT.
  Penn Hills, Plum, Hampton Township, Wilkinsburg, New Kensington, 
  O'hara Township, Oakmont, Fox Chapel, Arnold and Springdale around 
  800 PM EDT.

Other locations impacted by this tornadic thunderstorm include
Sewickley Hills, Cheswick, Ben Avon Heights, Sewickley Heights,
Reserve Township, Glenfield, Russellton, Haysville, Glen Osborne and
Curtisville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

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

&&

LAT...LON 4049 8017 4062 8016 4065 7973 4044 7977
TIME...MOT...LOC 2340Z 277DEG 29KT 4056 8010 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$
3 follow-up statements
494 
WWUS51 KPBZ 212347
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
747 PM EDT Thu Oct 21 2021

PAC007-212356-
/O.CAN.KPBZ.TO.W.0027.000000T0000Z-211022T0000Z/
Beaver PA-
747 PM EDT Thu Oct 21 2021

...THE TORNADO WARNING FOR EAST CENTRAL BEAVER COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

LAT...LON 4052 8010 4062 8011 4065 7973 4046 7977
TIME...MOT...LOC 2346Z 277DEG 29KT 4055 8003 

$$

PAC003-129-220000-
/O.CON.KPBZ.TO.W.0027.000000T0000Z-211022T0000Z/
Allegheny PA-Westmoreland PA-
747 PM EDT Thu Oct 21 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 800 PM EDT FOR
NORTHEASTERN ALLEGHENY AND NORTHWESTERN WESTMORELAND COUNTIES...
    
At 746 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Ross Township, moving east at 35 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This dangerous storm will be near...
  Pittsburgh, Shaler Township and Gibsonia around 750 PM EDT.
  Hampton Township, Etna and Sharpsburg around 755 PM EDT.
  Penn Hills, Plum, New Kensington, O'hara Township, Oakmont, Fox 
  Chapel, Arnold, Springdale, Aspinwall and Verona around 800 PM 
  EDT.

Other locations impacted by this tornadic thunderstorm include
Cheswick, Russellton, Ben Avon Heights, Curtisville, Reserve Township
and Pine Township.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

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

&&

LAT...LON 4052 8010 4062 8011 4065 7973 4046 7977
TIME...MOT...LOC 2346Z 277DEG 29KT 4055 8003 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$
659 
WWUS51 KPBZ 212353
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
753 PM EDT Thu Oct 21 2021

PAC003-129-220000-
/O.CON.KPBZ.TO.W.0027.000000T0000Z-211022T0000Z/
Allegheny PA-Westmoreland PA-
753 PM EDT Thu Oct 21 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 800 PM EDT FOR
NORTHEASTERN ALLEGHENY AND NORTHWESTERN WESTMORELAND COUNTIES...
    
At 753 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Shaler Township, or near Ross Township, moving east
at 35 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This dangerous storm will be near...
  Penn Hills, Oakmont, Verona and Blawnox around 805 PM EDT.
  Plum, New Kensington, Arnold, Tarentum, Springdale and 
  Brackenridge around 810 PM EDT.

Other locations impacted by this tornadic thunderstorm include
Cheswick and Russellton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not take shelter under highway overpasses. If you
cannot safely drive away from the tornado, as a last resort, either
park your vehicle and stay put, or abandon your vehicle and lie down
in a low lying area and protect yourself from flying debris.

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

&&

LAT...LON 4051 8001 4059 8000 4065 7973 4048 7978
TIME...MOT...LOC 2353Z 277DEG 29KT 4054 7995 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$
019 
WWUS51 KPBZ 212359
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
759 PM EDT Thu Oct 21 2021

PAC003-129-220009-
/O.EXP.KPBZ.TO.W.0027.000000T0000Z-211022T0000Z/
Allegheny PA-Westmoreland PA-
759 PM EDT Thu Oct 21 2021

...THE TORNADO WARNING FOR NORTHEASTERN ALLEGHENY AND NORTHWESTERN
WESTMORELAND COUNTIES WILL EXPIRE AT 800 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with this thunderstorm.

LAT...LON 4051 8001 4059 8000 4065 7973 4048 7978
TIME...MOT...LOC 2359Z 277DEG 29KT 4054 7992 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 21, 2:03 PM EDTSevere Thunderstorm WarningPBZButler, Lawrence, Mercer, Venango27 min
Oct 21, 2:36 PM EDTSpecial Weather StatementPBZMercer, Venango24 min
Oct 21, 2:50 PM EDTSpecial Weather StatementPBZLawrence25 min
Oct 21, 3:18 PM EDTSpecial Weather StatementPBZButler, Lawrence27 min
Oct 21, 3:49 PM EDTSpecial Weather StatementPBZClarion, Forest, Venango41 min
Oct 21, 4:08 PM EDTSpecial Weather StatementPBZWashington37 min
Oct 21, 4:32 PM EDTSpecial Weather StatementPBZClarion, Forest, Jefferson43 min
Oct 21, 4:47 PM EDTSpecial Weather StatementPBZAllegheny, Washington43 min
Oct 21, 5:48 PM EDTSevere Thunderstorm WarningPBZArmstrong, Indiana, Jefferson27 min
Oct 21, 6:00 PM EDTSpecial Weather StatementPBZLawrence, Mercer, Venango45 min
Oct 21, 6:18 PM EDTSpecial Weather StatementPBZBeaver42 min
Oct 21, 6:42 PM EDTTornado WarningPBZMercer18 min
Oct 21, 6:56 PM EDTTornado WarningPBZBeaver, Butler, Lawrence19 min
Oct 21, 6:57 PM EDTTornado WarningPBZWashington33 min
Oct 21, 7:13 PM EDTTornado WarningPBZGreene, Washington32 min
Oct 21, 7:19 PM EDTSpecial Weather StatementPBZAllegheny, Beaver, Butler41 min
Oct 21, 7:24 PM EDTTornado WarningPBZButler36 min
Oct 21, 7:26 PM EDTTornado WarningPBZWashington34 min

Nearby

Tornado Warnings in Pennsylvania, 2021Every tornado warning in 2021Tornadoes 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.