Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 128, NWS Pittsburgh, PA

July 7, 2021Clarion County, Forest County, Jefferson County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Jul 7, 2021, 5:24 PM EDT for Clarion County, Forest County, Jefferson County, Pennsylvania. It was in force for 51 min. 1 report 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: Jul 7, 2021, 5:24 PM EDT (21:24 UTC)
Expired: Jul 7, 2021, 6:15 PM EDT
In force: 51 min
Issued by: NWS Pittsburgh, PA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Clarion County, PA, Forest County, PA, Jefferson County, PA

The radar

The State College radar (KCCX), 98 km from the middle of the area, began a volume at 21:26 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
Jul 7, 5:28 PM EDT	TSTM WND DMG	Cooksburg, PA	TREES AND POWER LINES DOWN

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

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 4 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

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

Issued	Product	Office	Lasted
Jul 7, 3:31 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 9.4 hours before the alert went out and 136 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: 505 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 1230 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

008 
WUUS51 KPBZ 072124
SVRPBZ
PAC031-053-065-072215-
/O.NEW.KPBZ.SV.W.0128.210707T2124Z-210707T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Pittsburgh PA
524 PM EDT Wed Jul 7 2021

The National Weather Service in Pittsburgh has issued a

* Severe Thunderstorm Warning for...
  Northern Jefferson County in west central Pennsylvania...
  East central Clarion County in west central Pennsylvania...
  Southeastern Forest County in northwestern Pennsylvania...

* Until 615 PM EDT.

* At 524 PM EDT, a severe thunderstorm was located 8 miles northwest
  of Brookville, moving northeast at 40 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...
  Brockway...                       Strattanville...
  Summerville...                    Corsica...
  Sigel...                          Fisher...
  Clarington...                     Clear Creek State Park...
  Cook Forest State Park...         

This includes Interstate 80 in Pennsylvania between mile markers 69
and 85.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4107 7913 4115 7922 4122 7942 4141 7909
      4134 7909 4135 7908 4136 7903 4135 7902
      4137 7898 4145 7898 4145 7901 4148 7896
      4144 7896 4144 7897 4139 7897 4136 7896
      4126 7874
TIME...MOT...LOC 2124Z 237DEG 33KT 4123 7922 

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

3 follow-up statements

828 
WWUS51 KPBZ 072136
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
536 PM EDT Wed Jul 7 2021

PAC031-053-065-072215-
/O.CON.KPBZ.SV.W.0128.000000T0000Z-210707T2215Z/
Jefferson PA-Clarion PA-Forest PA-
536 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR NORTHERN JEFFERSON...EAST CENTRAL CLARION AND SOUTHEASTERN FOREST
COUNTIES...

At 536 PM EDT, a severe thunderstorm was located 9 miles north of
Brookville, moving northeast at 40 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...
Brockway...                       Strattanville...
Summerville...                    Corsica...
Sigel...                          Fisher...
Clarington...                     Clear Creek State Park...
Cook Forest State Park...         

This includes Interstate 80 in Pennsylvania between mile markers 69
and 85.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4107 7913 4115 7922 4122 7942 4141 7909
      4134 7909 4135 7908 4136 7903 4135 7902
      4137 7898 4145 7898 4145 7901 4148 7896
      4144 7896 4144 7897 4139 7897 4136 7896
      4126 7874
TIME...MOT...LOC 2136Z 237DEG 33KT 4129 7909 

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

895 
WWUS51 KPBZ 072155
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
555 PM EDT Wed Jul 7 2021

PAC031-053-065-072215-
/O.CON.KPBZ.SV.W.0128.000000T0000Z-210707T2215Z/
Jefferson PA-Clarion PA-Forest PA-
555 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR NORTHERN JEFFERSON...EAST CENTRAL CLARION AND SOUTHEASTERN FOREST
COUNTIES...

At 555 PM EDT, a severe thunderstorm was located near Portland Mills,
or 8 miles west of Ridgway, moving northeast at 40 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...                     Brockway...
Sigel...                          Fisher...
Clarington...                     Clear Creek State Park...
Cook Forest State Park...         

This includes Interstate 80 in Pennsylvania between mile markers 80
and 85.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4113 7901 4129 7931 4141 7909 4134 7909
      4135 7908 4136 7903 4135 7902 4137 7898
      4145 7898 4145 7901 4148 7896 4144 7896
      4144 7897 4139 7897 4136 7896 4126 7874
TIME...MOT...LOC 2155Z 237DEG 33KT 4139 7889 

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

007 
WWUS51 KPBZ 072207
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
607 PM EDT Wed Jul 7 2021

PAC031-053-065-072216-
/O.EXP.KPBZ.SV.W.0128.000000T0000Z-210707T2215Z/
Jefferson PA-Clarion PA-Forest PA-
607 PM EDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN JEFFERSON...EAST
CENTRAL CLARION AND SOUTHEASTERN FOREST COUNTIES WILL EXPIRE AT 615
PM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northwestern and west central Pennsylvania.

LAT...LON 4113 7901 4129 7931 4141 7909 4134 7909
      4135 7908 4136 7903 4135 7902 4137 7898
      4145 7898 4145 7901 4148 7896 4144 7896
      4144 7897 4139 7897 4136 7896 4126 7874
TIME...MOT...LOC 2206Z 237DEG 33KT 4143 7881 

$$

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 Jul 7, 5:10 PM EDT, 14 minutes earlier.

Area forecast discussion, Jul 7, 5:10 PM EDT, 14 minutes before

Area Forecast Discussion
National Weather Service Pittsburgh PA
510 PM EDT Wed Jul 7 2021

.SYNOPSIS...
Shower and thunderstorm chance will continue through Friday with the
gradual passage of a low pressure system.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Severe threat continues but is on the wane for most areas as
instability is diminishing and as outflow/pseudon warm front shifts
nwd. Warm, moist advection will continue overnight on the van of the
approaching trough, so iso/sct showers and thunderstorms will remain
in the wake of the severe threat.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
(Limited) diurnal heating and the approach/passage of a sfc cold
front will reinvigorate convection Thursday, with most locations
likely seeing rain. Little insolation will minimize instability and
mute any severe threat, but continued heavy rainfall may cause
issues, especially over locations that previously received heavy
rainfall. This threat could be further heightened if the region
(notably over southwest PA into northern WV) sees convective
enhancement due to the northward movement/position of Tropical Storm
Elsa. This will have to be monitored moving forward.

Precipitation will taper off Thursday night as the upper trough (and
Elsa) move east and weak dry advection develops within brief westerly
flow.

An additional shortwave will quickly follow Friday and tap into the
residual moisture in place to create another round of mostly
scattered showers and an isolated thunderstorm. Temperature Friday
will be near seasonal averages due to cold advection and only broken
sunshine.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A perturbed quasi-zonal flow may result in a series of troughs moving
through the upper Ohio River Valley into next week, providing
periodic chances for showers and thunderstorms and seasonable
temperature.

Model to model and run to run differences mean this period is fairly
low confidence and patience will be needed before any finer details
can be sussed out on actual temperature/precipitation trends, let
alone severe/flash flood threats.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Periodic restrictions and convection are likely through Thursday as
warm, moist advection continues with the advn of a cdfnt.

.Outlook...
A reprieve in periodic restrictions is expected on Saturday,
otherwise, the active pattern will continue into next week.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

Hazardous weather outlook, Jul 7, 3:31 PM EDT, 1 hour 53 minutes before

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
331 PM EDT Wed Jul 7 2021

OHZ039-048>050-057>059-068-069-PAZ029-031-075-076-WVZ002>004-012-021-
509>514-081945-
Tuscarawas-Coshocton-Harrison-Jefferson OH-Muskingum-Guernsey-
Belmont-Noble-Monroe-Washington-Greene-Fayette-
Higher Elevations of Fayette-Brooke-Ohio-Marshall-Wetzel-Marion-
Monongalia-Ridges of Eastern Monongalia and Northwestern Preston-
Preston-Eastern Preston-Western Tucker-Eastern Tucker-
331 PM EDT Wed Jul 7 2021

This Hazardous Weather Outlook is for east central Ohio, southwest
Pennsylvania, northern West Virginia and the northern panhandle of
West Virginia.

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

OHZ040-041-PAZ007>009-013>016-020>023-073-074-WVZ001-081945-
Carroll-Columbiana-Mercer-Venango-Forest-Lawrence-Butler-Clarion-
Jefferson PA-Beaver-Allegheny-Armstrong-Indiana-Westmoreland-
Higher Elevations of Westmoreland-Hancock-
331 PM EDT Wed Jul 7 2021

...SEVERE THUNDERSTORM WATCH 345 IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for east central Ohio, northwest
Pennsylvania, southwest Pennsylvania, western Pennsylvania and
northern West Virginia.

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

In the hours before

Local storm report, Jul 7, 4:45 PM EDT, 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
445 PM EDT WED JUL 7 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0335 PM     TSTM WND DMG     EDGEWOOD                40.43N 79.88W
07/07/2021                   ALLEGHENY          PA   PUBLIC

            LARGE TREE DOWN ALONG WEST SWISSVALE AVENUE.

&&

Local storm report, Jul 7, 4:51 PM EDT, 33 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
451 PM EDT WED JUL 07 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0430 PM     FLASH FLOOD      BRIDGEVILLE             40.36N  80.11W
07/07/2021                   ALLEGHENY          PA   NWS EMPLOYEE

            CREEK OUT OF BANK NEAR MCLAUGHLIN RUN AND BOWER HILL
            ROAD INTERSECTION.

&&

EVENT NUMBER PBZ2101875

15

Local storm report, Jul 7, 4:59 PM EDT, 25 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
459 PM EDT WED JUL 7 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0452 PM     FLASH FLOOD      BRIDGEVILLE             40.36N 80.11W
07/07/2021                   ALLEGHENY          PA   BROADCAST MEDIA

            EVACUATIONS UNDERWAY DUE TO FLOODING ALONG
            BALDWIN STREET IN BRIDGEVILLE.

&&

Local storm report, Jul 7, 5:03 PM EDT, 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
503 PM EDT WED JUL 7 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0435 PM     HAIL             2 ESE NEW CASTLE        40.99N 80.31W
07/07/2021  U0.75 INCH       LAWRENCE           PA   PUBLIC

            DIME SIZED HAIL (0.75 IN.).

&&

Local storm report, Jul 7, 5:08 PM EDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
508 PM EDT WED JUL 7 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0405 PM     FLASH FLOOD      1 W SWISSVALE           40.42N 79.90W
07/07/2021                   ALLEGHENY          PA   PUBLIC

            ROADWAY COMPLETELY COVERED WITH AT LEAST 3
            FEET OF WATER AT COMMERCIAL BLVD IN NEAR
            SWISSHELM PARK.

&&

Local storm report, Jul 7, 5:15 PM EDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
515 PM EDT WED JUL 7 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0415 PM     TSTM WND DMG     1 WNW BUTLER            40.87N 79.91W
07/07/2021                   BUTLER             PA   PUBLIC

            3-INCH TREE LIMBS BROKEN; POWER POLES
            BROKEN.

&&

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 1:36 PM EDT	Special Weather Statement	PBZ	Fayette	24 min
Jul 7, 1:57 PM EDT	Special Weather Statement	PBZ	Fayette	18 min
Jul 7, 2:01 PM EDT	Special Weather Statement	PBZ	Greene	14 min
Jul 7, 2:10 PM EDT	Special Weather Statement	PBZ	Westmoreland	20 min
Jul 7, 2:25 PM EDT	Severe Thunderstorm Warning	PBZ	Greene, Washington	20 min
Jul 7, 2:32 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Washington	13 min
Jul 7, 2:42 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver	18 min
Jul 7, 2:54 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Washington	36 min
Jul 7, 2:58 PM EDT	Special Weather Statement	PBZ	Allegheny	32 min
Jul 7, 2:59 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny	31 min
Jul 7, 3:01 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	29 min
Jul 7, 3:13 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Beaver, Washington	32 min
Jul 7, 3:19 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington, Westmoreland	26 min
Jul 7, 3:26 PM EDT	Flash Flood Warning	PBZ	Allegheny, Armstrong, Fayette, Washington, Westmoreland	2 hr
Jul 7, 3:36 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	24 min
Jul 7, 3:45 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Butler, Westmoreland	30 min
Jul 7, 3:47 PM EDT	Special Weather Statement	PBZ	Beaver	28 min
Jul 7, 3:53 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny	37 min
Jul 7, 4:01 PM EDT	Severe Thunderstorm Warning	PBZ	Butler	29 min
Jul 7, 4:21 PM EDT	Severe Thunderstorm Warning	PBZ	Beaver, Lawrence	39 min
Jul 7, 4:28 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion	32 min
Jul 7, 4:33 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Indiana, Jefferson	27 min
Jul 7, 4:35 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion, Venango	25 min
Jul 7, 4:40 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana, Westmoreland	13 min
Jul 7, 4:58 PM EDT	Severe Thunderstorm Warning	PBZ	Butler, Lawrence, Mercer, Venango	47 min
Jul 7, 4:59 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Clarion, Jefferson	31 min
Jul 7, 5:01 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Indiana, Jefferson	29 min
Jul 7, 5:06 PM EDT	Severe Thunderstorm Warning	PBZ	Clarion, Forest, Jefferson	24 min
Jul 7, 5:20 PM EDT	Severe Thunderstorm Warning	PBZ	Mercer, Venango	25 min
Jul 7, 5:24 PM EDT	Areal Flood Advisory	PBZ	Allegheny, Washington, Westmoreland	111 min
Jul 7, 6:40 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene	20 min
Jul 7, 7:19 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Washington	26 min
Jul 7, 7:22 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene, Washington	23 min
Jul 7, 7:33 PM EDT	Severe Thunderstorm Warning	PBZ	Fayette, Greene, Washington	27 min
Jul 7, 7:37 PM EDT	Severe Thunderstorm Warning	PBZ	Greene	23 min

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.