Alert archive / Pennsylvania / Tornado Warnings in 2021

Tornado Warning 21, NWS Pittsburgh, PA

October 21, 2021Mercer County, Pennsylvania

NWS Pittsburgh, PA issued this tornado warning at Oct 21, 2021, 6:42 PM EDT for Mercer County, Pennsylvania. It was in force for 18 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
Oct 21, 2021, 6:42 PM EDT (22:42 UTC)
Expired
Oct 21, 2021, 7:00 PM EDT
In force
18 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Mercer County, PA

The radar

The Pittsburgh radar (KPBZ), 79 km from the middle of the area, began a volume at 22:44 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, 10.7 hours before the alert went out and 94 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.

961 
WFUS51 KPBZ 212242
TORPBZ
PAC085-212300-
/O.NEW.KPBZ.TO.W.0021.211021T2242Z-211021T2300Z/

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

The National Weather Service in Pittsburgh has issued a

* Tornado Warning for...
  Central Mercer County in northwestern Pennsylvania...

* Until 700 PM EDT.
    
* At 641 PM EDT, a severe thunderstorm capable of producing a tornado
  was located over Hermitage, moving east at 40 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...
  Grove City around 700 PM EDT.

Other locations impacted by this tornadic thunderstorm include
Stoneboro, Clark, Sandy Lake, Fredonia, Jackson Center, Mercer, West
Middlesex and Maurice K Goddard State Park.

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 4118 8047 4130 8045 4139 8002 4115 8003
TIME...MOT...LOC 2241Z 263DEG 37KT 4122 8042 

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

$$
2 follow-up statements
719 
WWUS51 KPBZ 212252
SVSPBZ

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

PAC085-212300-
/O.CON.KPBZ.TO.W.0021.000000T0000Z-211021T2300Z/
Mercer PA-
652 PM EDT Thu Oct 21 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR EAST
CENTRAL MERCER COUNTY...
    
At 652 PM EDT, a severe thunderstorm capable of producing a tornado
was located 8 miles east of Hermitage, moving east at 40 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 tornadic thunderstorm will remain over mainly rural areas of
east central Mercer County, including the following locations...
Stoneboro, Sandy Lake, Fredonia, Mercer, Jackson Center and Maurice K
Goddard State Park.

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 4120 8038 4130 8037 4139 8002 4119 8003
TIME...MOT...LOC 2252Z 253DEG 36KT 4127 8027 

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

$$
237 
WWUS51 KPBZ 212258
SVSPBZ

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

PAC085-212307-
/O.EXP.KPBZ.TO.W.0021.000000T0000Z-211021T2300Z/
Mercer PA-
658 PM EDT Thu Oct 21 2021

...THE TORNADO WARNING FOR EAST CENTRAL MERCER COUNTY WILL EXPIRE AT
700 PM EDT...
                
The storm which prompted the warning has weakened below severe 
limits. Therefore, the warning will be allowed to expire.  However 
gusty winds are still possible with this thunderstorm.

LAT...LON 4120 8038 4130 8037 4139 8002 4119 8003
TIME...MOT...LOC 2257Z 263DEG 37KT 4127 8024 

$$

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, 6:56 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
Oct 21, 7:40 PM EDTTornado WarningPBZAllegheny, Beaver, Westmoreland20 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.