Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 151, NWS Pittsburgh, PA

August 25, 2020Armstrong County, Butler County, Clarion County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Aug 25, 2020, 1:36 PM EDT for Armstrong County, Butler County, Clarion County, Pennsylvania. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 25, 2020, 1:36 PM EDT (17:36 UTC)
Expired
Aug 25, 2020, 2:15 PM EDT
In force
39 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Armstrong County, PA, Butler County, PA, Clarion County, PA

The radar

The Pittsburgh radar (KPBZ), 72 km from the middle of the area, began a volume at 17:38 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 watch it was issued in

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

IssuedProductOfficeLasted
Aug 25, 1:21 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 5.6 hours before the alert went out and 75 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 2020-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1286 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Pittsburgh, PA at 12:00Z on 2020-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 117 square meters per square second.193958Sfc1 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
1286 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
1021 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
117 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.1

Open this sounding in Storm Lab

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 Aug 25, 12:42 PM EDT, 54 minutes earlier.

Area forecast discussion, Aug 25, 12:42 PM EDT, 54 minutes before
Area Forecast Discussion
National Weather Service Pittsburgh PA
1242 PM EDT Tue Aug 25 2020

.SYNOPSIS...
Warm and humid conditions will continue today with scattered
thunderstorms, some of which may generate damaging wind gusts.

&&

.NEAR TERM /THROUGH TONIGHT/...
The next in series of shortwaves is generating more convection this
afternoon as per scattered activity developing off Lake Erie. More
widespread storms are anticipated with the boundary sagging toward
the I 70 corridor. This activity is expected to congeal into a linear
MCS which will plough across the mid Atlantic region early this
evening.

For the upper Ohio, the area remains under the threat for scattered
severe risk with the primary hazard from damaging wind. Shear and
increasing instability favor multicell to short bowing segments with
eventual congeal into an organized MCS still possible as mentioned
above. The better chance for widespread severe is indicated along,
and south of I 70 beginning either side of 4 pm.

Convection will weaken and wane into the late evening and overnight
hours as shortwave ridging suppresses residual showers and clouds.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Another shortwavew is projected for Wednesday passage. That system
will pull the frontal boundary north and eastward once again and
destabilize the area via increased dewpoints and warmth. Deep layer
shear remains favorable for severe and the Upr OH rmns under a slight
svr risk. Primary problem will again be damaging gusts during the mid
afternoon with weakening toward evening.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Flow is expected be remain relatively fast and become more zonal for
the latter half of the week. This will support a series of
progressive shortwave passages with periodic rain chance fueled by
the northern fringe of tropical moisture funneling over the mid
Atlantic region. A stronger cold front/trough passage is indicated
for the weekend to continue the rain chance. Expect seasonable
temperature throughout.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Storms will advance through the entire region this afternoon as a
shortwave crosses the Great Lakes. Strong wind gusts are likely to be
embedded within convection due deep wind shear aloft and dry air
accelerated to the surface; MVFR to IFR vis may occur during heavy
downpours. In areas separated from convection, VFR will prevail.

Showers and storms will fizzle out after dark; with dry air advancing
into the region VFR will prevail.

A new shortwave tomorrow will create thunderstorm chances again in
the afternoon in eastern Ohio; added VCTS for ZZV but more sites may
need to be added later.

.Outlook...
VFR conditions will largely prevail through much of this week with
only periodic restrictions due to thunderstorms and morning fog.

&&

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

&&
Hazardous weather outlook, Aug 25, 1:26 PM EDT, 10 minutes before
Hazardous Weather Outlook
National Weather Service Pittsburgh PA
126 PM EDT Tue Aug 25 2020

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021-509>514-261730-
Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-
Jefferson OH-Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-
Forest-Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-
Armstrong-Indiana-Washington-Greene-Westmoreland-Westmoreland Ridges-
Fayette-Fayette Ridges-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion-
Monongalia-Ridges of Eastern Monongalia and Northwestern Preston-
Preston-Eastern Preston-Western Tucker-Eastern Tucker-
126 PM EDT Tue Aug 25 2020

...SEVERE THUNDERSTORM WATCH 449 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for western Maryland, east
central Ohio, northwest Pennsylvania, southwest Pennsylvania,
western Pennsylvania, northern West Virginia and the northern
panhandle of 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...Wednesday through Monday.

There is a slight risk for severe thunderstorms on Wednesday. The
primary hazard will be damaging wind gusts.

.SPOTTER INFORMATION STATEMENT...

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

In the hours before

Local storm report, Aug 25, 8:54 AM EDT, 4 hours 42 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Aug 25, 8:55 AM EDT, 4 hours 41 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Local storm report, Aug 25, 9:33 AM EDT, 4 hours 3 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
933 AM EDT TUE AUG 25 2020

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

0915 AM     TSTM WND DMG     JEANNETTE               40.33N  79.61W
08/25/2020                   WESTMORELAND       PA   911 CALL CENTER

            TREES DOWN AT 125 ASHBAUGH RD.

&&

EVENT NUMBER PBZ2001233
Local storm report, Aug 25, 9:37 AM EDT, 3 hours 59 minutes before
PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE PITTSBURGH PA
937 AM EDT TUE AUG 25 2020

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

0817 AM     TSTM WND DMG     JEANNETTE               40.33N  79.61W
08/25/2020                   WESTMORELAND       PA   911 CALL CENTER

            TREES DOWN AT 125 ASHBAUGH RD.

&&

CORRECTED EVENT TIME

EVENT NUMBER PBZ2001233
Special weather statement, Aug 25, 1:18 PM EDT, 18 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
118 PM EDT Tue Aug 25 2020

OHZ039-040-048>050-057-058-251800-
Guernsey-Jefferson-Tuscarawas-Coshocton-Harrison-Muskingum-Carroll-
118 PM EDT Tue Aug 25 2020

...AN AREA OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING SMALL HAIL
AND GUSTY WIND WILL AFFECT CENTRAL HARRISON...WEST CENTRAL
JEFFERSON...NORTHWESTERN GUERNSEY...COSHOCTON...NORTHEASTERN
MUSKINGUM...SOUTHWESTERN CARROLL AND TUSCARAWAS COUNTIES...

At 117 PM EDT, strong thunderstorms were clustered near Farmerstown,
or 11 miles southwest of Dover, moving southeast at 35 mph.

Wind gusts up to 55 mph and small hail are possible with these
storms.

Locations impacted include...
New Philadelphia...               Dover...
Coshocton...                      Uhrichsville...
Freeport...                       Newcomerstown...
Dennison...                       Strasburg...
West Lafayette...                 Sugarcreek...
Gnadenhutten...                   Tuscarawas...

This includes  Interstate 77 in Ohio between mile markers 51 and 94.

Storms may intensify, so monitor local radio or television stations
for additional information and possible warnings from the National
Weather Service.

LAT...LON 4046 8218 4044 8168 4063 8167 4065 8147
      4067 8146 4066 8144 4065 8144 4065 8133
      4037 8084 3998 8183 4035 8219
TIME...MOT...LOC 1717Z 305DEG 31KT 4045 8167
Local storm report, Aug 25, 1:35 PM EDT, 1 minute before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
135 PM EDT TUE AUG 25 2020

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

0133 PM     TSTM WND DMG     1 NNW PETROLIA          41.03N  79.72W
08/25/2020                   BUTLER             PA   911 CALL CENTER

            TREES AND WIRES DOWN IN WASHINGTON TOWNSHIP

&&

EVENT NUMBER PBZ2001234

SKH

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 25, 6:41 AM EDTSevere Thunderstorm WarningPBZAllegheny, Armstrong, Butler, Westmoreland19 min
Aug 25, 7:10 AM EDTSpecial Weather StatementPBZWestmoreland20 min
Aug 25, 7:41 AM EDTSpecial Weather StatementPBZWestmoreland49 min
Aug 25, 7:55 AM EDTSevere Thunderstorm WarningPBZArmstrong, Indiana, Westmoreland50 min
Aug 25, 8:06 AM EDTSpecial Weather StatementPBZAllegheny24 min
Aug 25, 8:18 AM EDTSevere Thunderstorm WarningPBZFayette, Westmoreland27 min
Aug 25, 9:05 AM EDTSevere Thunderstorm WarningPBZFayette25 min
Aug 25, 11:58 AM EDTSevere Thunderstorm WarningPBZMercer, Venango32 min
Aug 25, 12:29 PM EDTSevere Thunderstorm WarningPBZArmstrong, Butler, Clarion, Forest, Mercer, Venango46 min
Aug 25, 1:12 PM EDTSevere Thunderstorm WarningPBZArmstrong, Butler, Clarion, Mercer, Venango48 min
Aug 25, 2:07 PM EDTSevere Thunderstorm WarningPBZArmstrong, Butler, Clarion, Mercer, Venango38 min
Aug 25, 2:09 PM EDTSevere Thunderstorm WarningPBZAllegheny, Armstrong, Butler, Indiana, Westmoreland51 min
Aug 25, 2:26 PM EDTSevere Thunderstorm WarningPBZFayette23 min
Aug 25, 2:29 PM EDTSpecial Weather StatementPBZWashington31 min
Aug 25, 2:34 PM EDTSevere Thunderstorm WarningPBZAllegheny, Armstrong, Indiana, Westmoreland41 min
Aug 25, 3:07 PM EDTSevere Thunderstorm WarningPBZGreene, Washington38 min
Aug 25, 3:15 PM EDTSevere Thunderstorm WarningPBZArmstrong, Fayette, Indiana, Westmoreland45 min
Aug 25, 3:39 PM EDTSevere Thunderstorm WarningPBZFayette, Greene, Washington51 min
Aug 25, 4:00 PM EDTSpecial Weather StatementPBZAllegheny30 min
Aug 25, 4:08 PM EDTSpecial Weather StatementPBZWestmoreland37 min
Aug 25, 4:13 PM EDTSevere Thunderstorm WarningPBZWestmoreland32 min
Aug 25, 4:20 PM EDTSevere Thunderstorm WarningPBZFayette, Greene40 min
Aug 25, 4:40 PM EDTSpecial Weather StatementPBZFayette, Washington50 min
Aug 25, 5:01 PM EDTSevere Thunderstorm WarningPBZAllegheny, Fayette, Washington, Westmoreland29 min
Aug 25, 5:05 PM EDTSevere Thunderstorm WarningPBZFayette, Westmoreland25 min
Aug 25, 5:34 PM EDTSpecial Weather StatementPBZFayette26 min
Aug 25, 1:18 PM EDTSpecial Weather StatementPBZCoshocton, Harrison, Tuscarawas42 min
Aug 25, 1:43 PM EDTSevere Thunderstorm WarningPBZGuernsey, Harrison, Tuscarawas32 min
Aug 25, 1:53 PM EDTSevere Thunderstorm WarningPBZCoshocton, Tuscarawas52 min
Aug 25, 1:57 PM EDTSevere Thunderstorm WarningPBZCoshocton, Guernsey, Harrison, Muskingum, Tuscarawas48 min
Aug 25, 2:00 PM EDTSpecial Weather StatementPBZMuskingum30 min
Aug 25, 2:23 PM EDTSevere Thunderstorm WarningPBZBelmont, Guernsey, Harrison, Jefferson52 min
Aug 25, 2:47 PM EDTSevere Thunderstorm WarningPBZCoshocton43 min
Aug 25, 2:52 PM EDTSpecial Weather StatementPBZBelmont38 min
Aug 25, 3:11 PM EDTSevere Thunderstorm WarningPBZCoshocton, Guernsey, Muskingum, Noble49 min
Aug 25, 3:26 PM EDTSevere Thunderstorm WarningPBZBelmont, Coshocton, Guernsey, Harrison, Muskingum, Noble and 1 more49 min
Aug 25, 3:35 PM EDTSpecial Weather StatementPBZMonroe25 min
Aug 25, 3:57 PM EDTSevere Thunderstorm WarningPBZGuernsey, Monroe, Muskingum, Noble29 min
Aug 25, 8:55 AM EDTSpecial Weather StatementPBZTucker35 min
Aug 25, 3:13 PM EDTSpecial Weather StatementPBZWetzel32 min
Aug 25, 5:03 PM EDTSevere Thunderstorm WarningPBZPreston, Tucker42 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Every severe thunderstorm warning in 2020

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.