Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 159, NWS Pittsburgh, PA

August 21, 2018Indiana County, Westmoreland County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Aug 21, 2018, 1:52 PM EDT for Indiana County, Westmoreland County, Pennsylvania. It was in force for 38 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 21, 2018, 1:52 PM EDT (17:52 UTC)
Expired
Aug 21, 2018, 2:30 PM EDT
In force
38 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Indiana County, PA, Westmoreland County, PA

The radar

The Pittsburgh radar (KPBZ), 80 km from the middle of the area, began a volume at 17:54 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 (KAGC), launched 12:00Z, 5.9 hours before the alert went out and 70 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 2018-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 340 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 2018-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 211 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
340 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
811 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
211 m²/s²
0-3 km storm-relative helicity
223 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.5

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 21, 9:22 AM EDT, 4 hours 30 minutes earlier.

Area forecast discussion, Aug 21, 9:22 AM EDT, 4 hours 30 minutes before
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Hazardous weather outlook, Aug 21, 9:24 AM EDT, 4 hours 28 minutes before
Hazardous Weather Outlook...UPDATED
National Weather Service Pittsburgh PA
924 AM EDT Tue Aug 21 2018

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021-509>514-221330-
Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson-
Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest-
Lawrence-Butler-Clarion-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-
924 AM EDT Tue Aug 21 2018

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

.DAY ONE...Today and Tonight.

Strong to severe storms capable of damaging wind gusts and a couple
of tornadoes will be possible this afternoon and evening. Heavy
downpours also will be possible, which could lead to localized
flooding.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time, but spotters are
encouraged to report severe weather to the National Weather Service.

Kramar

In the hours before

Special weather statement, Aug 21, 12:50 PM EDT, 1 hour 2 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
1250 PM EDT TUE AUG 21 2018

PAZ031-WVZ004-012-211715-
Greene-Marshall-Wetzel-
1250 PM EDT TUE AUG 21 2018

...A STRONG THUNDERSTORM CAPABLE OF PRODUCING GUSTY WIND WILL AFFECT
SOUTHWESTERN GREENE...WETZEL AND SOUTHEASTERN MARSHALL COUNTIES...

At 1249 PM EDT, a strong thunderstorm was located near Pine Grove, or
near New Martinsville, moving northeast at 40 mph.

Wind gusts up to 45 mph are possible with this storm.

Locations impacted include...
New Martinsville...               Pine Grove...
Hundred...                        Jacksonburg...
Porters Falls...                  Wileyville...
Burton...                         Big Run...
Reader...                         Earnshaw...
Knob Fork...                      Littleton...

Frequent cloud to ground lightning is occurring with this storm. Seek
safe shelter inside a building or vehicle.

LAT...LON 3951 8074 3954 8078 3955 8079 3956 8081
      3956 8082 3958 8083 3958 8085 3960 8085
      3958 8088 3960 8093 3979 8054 3967 8040
      3965 8039 3963 8040 3964 8043 3963 8044
      3962 8044 3949 8073
TIME...MOT...LOC 1649Z 241DEG 37KT 3957 8078

CL
Special weather statement, Aug 21, 1:18 PM EDT, 34 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
118 PM EDT TUE AUG 21 2018

PAZ029-031-WVZ004-211745-
Greene-Washington-Marshall-
118 PM EDT TUE AUG 21 2018

...A STRONG THUNDERSTORM CAPABLE OF PRODUCING GUSTY WIND WILL AFFECT
SOUTHWESTERN WASHINGTON...NORTHWESTERN GREENE AND EASTERN MARSHALL
COUNTIES...

At 117 PM EDT, a strong thunderstorm was located near Cameron, or
near Moundsville, moving northeast at 45 mph.

A wind gust of 45 MPH was earlier reported from this storm near New
Martinsville. Gusts of that speed remain possible.

Locations impacted include...
Cameron...                        West Finley...
Nineveh...                        Rocklick...
Lynn Camp...                      Lone Oak...
Grove Oak...                      Glen Easton...
Dallas...                         Beelers Station...

LAT...LON 3985 8079 4002 8053 4002 8052 4003 8052
      4008 8044 3994 8026 3976 8069
TIME...MOT...LOC 1717Z 233DEG 37KT 3983 8068

CL
Special weather statement, Aug 21, 1:25 PM EDT, 27 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
125 PM EDT TUE AUG 21 2018

WVZ511>514-211800-
Eastern Preston-Eastern Tucker-Western Tucker-Preston-
125 PM EDT TUE AUG 21 2018

...A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING GUSTY WIND AND
HEAVY RAIN WILL AFFECT NORTHWESTERN TUCKER AND SOUTHERN PRESTON
COUNTIES...

At 125 PM EDT, radar indicated strong thunderstorms were located
along a line extending from 10 miles south of Newburg to 7 miles
northeast of Belington. Movement was northeast at 25 mph.

Wind gusts up to 45 mph are possible with these storms.

Locations impacted include...
Parsons...                        Hannahsville...
Aurora...                         Elgon...
Benbush...                        Lead Mine...
Pifer Moutain...                  Davisville...
Saint George...                   Cathedral State Park...

Torrential rainfall also is occurring with these storms and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3911 7980 3912 7983 3913 7984 3918 7983
      3918 7982 3920 7983 3923 7981 3924 7982
      3924 7985 3926 7985 3934 7950 3911 7951
      3908 7978
TIME...MOT...LOC 1725Z 237DEG 20KT 3924 7985 3912 7986

Kramar
Special weather statement, Aug 21, 1:42 PM EDT, 10 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
142 PM EDT TUE AUG 21 2018

PAZ023-073-074-211815-
Westmoreland Ridges-Westmoreland-Indiana-
142 PM EDT TUE AUG 21 2018

...A STRONG THUNDERSTORM CAPABLE OF PRODUCING GUSTY WIND WILL AFFECT
SOUTHEASTERN INDIANA AND SOUTHEASTERN WESTMORELAND COUNTIES...

At 142 PM EDT, a strong thunderstorm was located over Ligonier, or
near Latrobe, moving northeast at 25 mph.

Wind gusts up to 55 mph are possible with this storm.

Locations impacted include...
Latrobe...                        McChesneytown-Loyalhanna...
Derry...                          Lawson Heights...
Ligonier...                       Black Lick...
New Florence...                   Seward...
Bolivar...                        Youngstown...
Armagh...                         Brush Vly...

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

LAT...LON 4037 7899 4026 7908 4017 7930 4031 7941
      4060 7896 4053 7890
TIME...MOT...LOC 1742Z 235DEG 23KT 4025 7929

CL

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 1:42 PM EDTSpecial Weather StatementPBZWestmoreland33 min
Aug 21, 2:13 PM EDTSpecial Weather StatementPBZArmstrong32 min
Aug 21, 2:35 PM EDTTornado WarningPBZArmstrong, Clarion, Jefferson25 min
Aug 21, 3:11 PM EDTSevere Thunderstorm WarningPBZJefferson34 min
Aug 21, 3:30 PM EDTAreal Flood AdvisoryPBZJefferson3 hr
Aug 21, 3:42 PM EDTAreal Flood AdvisoryPBZJefferson3 hr
Aug 21, 4:04 PM EDTSpecial Weather StatementPBZJefferson26 min
Aug 21, 5:29 PM EDTSpecial Weather StatementPBZButler31 min
Aug 21, 7:13 PM EDTFlash Flood WarningPBZArmstrong, Clarion, Indiana, Jefferson3 hr
Aug 21, 12:02 AM EDTSpecial Weather StatementPBZNoble43 min
Aug 21, 6:32 AM EDTSpecial Weather StatementPBZBrooke28 min
Aug 21, 12:50 PM EDTSpecial Weather StatementPBZWetzel25 min
Aug 21, 1:18 PM EDTSpecial Weather StatementPBZMarshall27 min
Aug 21, 1:25 PM EDTSpecial Weather StatementPBZTucker35 min
Aug 21, 2:06 PM EDTSpecial Weather StatementPBZTucker39 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2018Every severe thunderstorm warning in 2018

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.