Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2004
Severe Thunderstorm Watch 768
The Storm Prediction Center issued this severe thunderstorm watch at Aug 20, 2004, 4:25 PM EDT for Garrett County, Maryland; 13 counties in Pennsylvania; 13 counties in West Virginia. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 20, 2004, 4:25 PM EDT (20:25 UTC)
- Expired
- Aug 20, 2004, 9:00 PM EDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
All 27 counties
Garrett County, MD, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Cambria County, PA, Clearfield County, PA, Fayette County, PA, Greene County, PA, Indiana County, PA, Lawrence County, PA, Somerset County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Doddridge County, WV, Hancock County, WV, Harrison County, WV, Marion County, WV, Marshall County, WV, Mineral County, WV, Monongalia County, WV, Ohio County, WV, Preston County, WV, Taylor County, WV, Tyler County, WV, Wetzel County, WV
The radar
The Pittsburgh radar (KPBZ), 68 km from the middle of the area, began a volume at 20:27 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.
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 4:34 PM EDT | Severe Thunderstorm Warning | PBZ | Hancock | 26 min |
| Aug 20, 4:35 PM EDT | Severe Thunderstorm Warning | PBZ | Beaver | 55 min |
| Aug 20, 4:47 PM EDT | Tornado Warning | PBZ | Beaver | 43 min |
| Aug 20, 5:01 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny | 59 min |
| Aug 20, 5:09 PM EDT | Severe Thunderstorm Warning | PBZ | Butler | 66 min |
| Aug 20, 5:21 PM EDT | Severe Thunderstorm Warning | PBZ | Washington | 54 min |
| Aug 20, 5:25 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong | 65 min |
| Aug 20, 5:58 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny | 62 min |
| Aug 20, 6:27 PM EDT | Severe Thunderstorm Warning | PBZ | Westmoreland | 63 min |
| Aug 20, 6:34 PM EDT | Severe Thunderstorm Warning | PBZ | Westmoreland | 56 min |
| Aug 20, 6:44 PM EDT | Severe Thunderstorm Warning | PBZ | Indiana | 61 min |
| Aug 20, 6:49 PM EDT | Severe Thunderstorm Warning | CTP | Clearfield, Elk | 56 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 8.4 hours before the alert went out and 52 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
- 181 J/kg
- Mixed-layer CIN
- -102 J/kg
- Mixed-layer LCL
- 860 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 19 m²/s²
- 0-3 km storm-relative helicity
- 71 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 19, 8:28 PM EDT | Mesoscale Discussion | SPC | Anne Arundel, Baltimore, Carroll, Cecil, Frederick, Harford and 5 more | 92 min |
| Aug 20, 4:03 PM EDT | Mesoscale Discussion | SPC | Allegany, Baltimore, Carroll, Frederick, Garrett, Howard and 3 more | 2 hr |
| Aug 20, 7:15 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 90 min |
| Aug 20, 11:56 AM EDT | Mesoscale Discussion | SPC | Bradford, Centre, Clinton, Columbia, Lackawanna, Luzerne and 10 more | 2 hr |
| Aug 20, 2:05 PM EDT | Severe Thunderstorm Watch | SPC | Blair, Bradford, Cambria, Cameron, Carbon, Centre and 27 more | 5 hr |
| Aug 20, 3:41 PM EDT | Mesoscale Discussion | SPC | Blair, Bradford, Cambria, Cameron, Carbon, Centre and 27 more | 2 hr |
| Aug 20, 6:10 PM EDT | Severe Thunderstorm Watch | SPC | Bradford, Cameron, Carbon, Centre, Clinton, Columbia and 21 more | 5 hr |
Nearby
Severe Thunderstorm Watches in Pennsylvania, 2004Severe Thunderstorm Watches in West Virginia, 2004Severe Thunderstorm Watches in Maryland, 2004Every severe thunderstorm watch in 2004
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.