Alert archive / West Virginia / Severe Thunderstorm Warnings in 2020
Severe Thunderstorm Warning 187, NWS Pittsburgh, PA
NWS Pittsburgh, PA issued this severe thunderstorm warning at Aug 27, 2020, 7:40 PM EDT for 4 counties in Pennsylvania; 5 counties in West Virginia. It was in force for 65 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 27, 2020, 7:40 PM EDT (23:40 UTC)
- Expired
- Aug 27, 2020, 8:45 PM EDT
- In force
- 65 min
- Issued by
- NWS Pittsburgh, PA
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Fayette County, PA, Greene County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Preston County, WV
The radar
The Pittsburgh radar (KPBZ), 64 km from the middle of the area, began a volume at 23:43 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.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 27, 5:32 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 11.7 hours before the alert went out and 51 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.
- Mixed-layer CAPE
- 277 J/kg
- Mixed-layer CIN
- -54 J/kg
- Mixed-layer LCL
- 931 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 127 m²/s²
- 0-3 km storm-relative helicity
- 127 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.8
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 27, 3:03 PM EDT, 4 hours 37 minutes earlier.
Area forecast discussion, Aug 27, 3:03 PM EDT, 4 hours 37 minutes before
Area Forecast Discussion National Weather Service Pittsburgh PA 303 PM EDT Thu Aug 27 2020 .SYNOPSIS... Strong to severe thunderstorms are possible again this evening and again on Friday. Widespread rain is expected Friday night through Saturday with drier weather expected Sunday and Monday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... No change was made for the afternoon update as convection has been limited thus far by very warm, and dry mid levels. Nevertheless, a shortwave moving across the Lakes region indicates a mid level thermal trough which is expected to support dvlpmnt and more balanced updraft potential by early eve. SPC has maintained a slight risk over the forecast area given downdraft potential and increased deep layer shear, especially over the I80 corridor. The severe threat will diminish as instability wanes this eve; however, enough WNW flow aloft will remain with weak shortwaves to keep isolated/scattered showers going in the warm, moist environment. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/... Showers and thunderstorms will continue on Friday with a crossing weak sfc low and advancing upper trough amid increasing deep tropical moisture with the remnants of Laura. Isolated severe storms are possible during the afternoon hours with strong, damaging winds being the primary threat. Training storms may also cause localized flash flooding. The remnants of Hurricane Laura will cross the region late Friday night into Saturday, eventually merging with the low/trough crossing southern Ontario. Meanwhile, a cold front will cross the upper Midwest into the Ohio Valley. Deep tropical moisture associated with Laura's remnants in advance of this front will serve as the focus for widespread rainfall late Friday night into Saturday. Efficient rainfall with training thunderstorms will pose a flash flooding threat across the area. WPC has highlight most of the region in a slight risk for excessive rainfall. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... The pattern becomes more amplified on Saturday as a ridge builds over the upper Midwest. This feature will cross the Ohio Valley late in the weekend, bringing a dry period to the area for Sunday and Monday. Precipitation chances return on Tuesday with a crossing trough. Near-average temperatures are expected through the long term. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... Isolated to scattered thunderstorms will be possible through the evening within disturbed flow aloft with best chance from PIT nwd. Convection should generally diminish overnight with the loss of diurnal heating, though additional shortwaves may keep isolated showers going into Friday. Moisture pooling along the eastern slopes will likely lead to MVFR cig development Friday morning, with a stationary sfc boundary sitting north of the forecast area. Additional shortwave support plus increasing tropical moisture will lead to more widespread convection Friday. .Outlook... Restrictions due to showers and thunderstorms are likely through Saturday as remnants of Laura move past the region. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. &&
Hazardous weather outlook, Aug 27, 7:34 PM EDT, 6 minutes before
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Local storm report, Aug 27, 6:46 PM EDT, 54 minutes before
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</html>Local storm report, Aug 27, 6:47 PM EDT, 53 minutes before
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</html>The office that day
Everything else NWS Pittsburgh, PA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 4:18 PM EDT | Special Weather Statement | PBZ | Mercer | 27 min |
| Aug 27, 4:44 PM EDT | Severe Thunderstorm Warning | PBZ | Beaver, Butler, Lawrence, Mercer | 46 min |
| Aug 27, 4:48 PM EDT | Special Weather Statement | PBZ | Butler | 27 min |
| Aug 27, 4:56 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Butler, Clarion, Lawrence, Mercer, Venango | 34 min |
| Aug 27, 5:26 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Armstrong, Beaver, Butler, Clarion, Indiana and 2 more | 64 min |
| Aug 27, 5:33 PM EDT | Severe Thunderstorm Warning | PBZ | Beaver, Lawrence | 42 min |
| Aug 27, 5:40 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Indiana, Jefferson | 50 min |
| Aug 27, 6:08 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Beaver, Washington | 52 min |
| Aug 27, 6:11 PM EDT | Severe Thunderstorm Warning | PBZ | Beaver, Washington | 49 min |
| Aug 27, 6:32 PM EDT | Special Weather Statement | PBZ | Westmoreland | 28 min |
| Aug 27, 6:41 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Fayette, Washington, Westmoreland | 64 min |
| Aug 27, 7:02 PM EDT | Special Weather Statement | PBZ | Washington | 28 min |
| Aug 27, 7:10 PM EDT | Severe Thunderstorm Warning | PBZ | Washington | 50 min |
| Aug 27, 7:04 PM EDT | Severe Thunderstorm Warning | PBZ | Belmont, Carroll, Harrison, Jefferson, Tuscarawas | 41 min |
Nearby
Severe Thunderstorm Warnings in West Virginia, 2020Severe 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.