Alert archive / Pennsylvania / Tornado Watches in 2002
Tornado Watch 171
The Storm Prediction Center issued this tornado watch at Apr 28, 2002, 2:30 PM EDT for 22 counties in Pennsylvania; Marshall County, West Virginia. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2002, 2:30 PM EDT (18:30 UTC)
- Expired
- Apr 28, 2002, 8:00 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
All 23 counties
Allegheny County, PA, Armstrong County, PA, Bedford County, PA, Blair County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Elk County, PA, Fayette County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, McKean County, PA, Potter County, PA, Somerset County, PA, Tioga County, PA, Washington County, PA, Westmoreland County, PA, Marshall County, WV
The radar
The Pittsburgh radar (KPBZ), 94 km from the middle of the area, began a volume at 18:30 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
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 2:45 PM EDT | Severe Thunderstorm Warning | PBZ | Washington | 60 min |
| Apr 28, 2:54 PM EDT | Severe Thunderstorm Warning | CTP | McKean | 66 min |
| Apr 28, 2:58 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny | 62 min |
| Apr 28, 2:59 PM EDT | Severe Thunderstorm Warning | CTP | Elk | 61 min |
| Apr 28, 3:05 PM EDT | Tornado Warning | PBZ | Marshall | 40 min |
| Apr 28, 3:20 PM EDT | Severe Thunderstorm Warning | PBZ | Greene | 55 min |
| Apr 28, 3:40 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Westmoreland | 65 min |
| Apr 28, 3:51 PM EDT | Severe Thunderstorm Warning | PBZ | Indiana | 54 min |
| Apr 28, 4:00 PM EDT | Severe Thunderstorm Warning | PBZ | Fayette | 60 min |
| Apr 28, 4:05 PM EDT | Severe Thunderstorm Warning | CTP | Cambria, Somerset | 55 min |
| Apr 28, 4:17 PM EDT | Severe Thunderstorm Warning | CTP | Bedford, Blair | 58 min |
| Apr 28, 4:26 PM EDT | Severe Thunderstorm Warning | CTP | Centre | 64 min |
| Apr 28, 4:27 PM EDT | Severe Thunderstorm Warning | CTP | Potter, Tioga | 63 min |
| Apr 28, 4:40 PM EDT | Severe Thunderstorm Warning | CTP | Huntingdon | 65 min |
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 6.5 hours before the alert went out and 87 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
- 6 J/kg
- Mixed-layer CIN
- -93 J/kg
- Mixed-layer LCL
- 705 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 134 m²/s²
- 0-3 km storm-relative helicity
- 191 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 WWUS20 KWNS 281820 SEL1 SPC WW 281815 PAZ000-290000- URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 171 STORM PREDICTION CENTER NORMAN OK 215 PM EDT SUN APR 28 2002 THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF WESTERN AND CENTRAL PENNSYLVANIA EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 230 PM UNTIL 800 PM EDT. TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE TORNADO WATCH AREA IS ALONG AND 60 STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES SOUTH SOUTHWEST OF LATROBE PENNSYLVANIA TO 50 MILES EAST NORTHEAST OF BRADFORD PENNSYLVANIA. REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. OTHER WATCH INFORMATION... CONTINUE...WW 166...WW 167...WW 168...WW 169...WW 170... DISCUSSION...SEVERE STORMS ARE DEVELOPING AHEAD OF APPROACHING COLD FRONT/UPPER LEVEL TROUGH. TEMPERATURES HAVE WARMED INTO THE 70S RESULTING IN MODERATE INSTABILITY. THOUGH THE MAIN THREAT WILL BE DAMAGING WINDS/LARGE HAIL...STRONG LOW LEVEL SHEAR WILL BE SUFFICIENT FOR ROTATING STORMS AND TORNADOES. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 1 INCH...EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM MOTION VECTOR 24045. ...IMY 420,0763 394,0783 394,0804 420,0785
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 11:45 AM EDT | Tornado Watch | SPC | Beaver, Butler, Crawford, Forest, Lawrence, Mercer and 2 more | 5 hr |
| Apr 28, 5:00 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Berks, Bradford, Bucks, Carbon, Chester and 30 more | 5 hr |
| Apr 28, 12:30 PM EDT | Tornado Watch | SPC | Cabell, Kanawha, Lincoln, Putnam, Wayne | 5 hr |
| Apr 28, 1:30 PM EDT | Tornado Watch | SPC | Barbour, Boone, Braxton, Calhoun, Clay, Doddridge and 32 more | 4 hr |
| Apr 28, 3:30 PM EDT | Tornado Watch | SPC | Berkeley, Hampshire, Hardy, Jefferson, Morgan, Pendleton | 6 hr |
| Apr 28, 5:00 PM EDT | Severe Thunderstorm Watch | SPC | Barbour, Boone, Braxton, Calhoun, Clay, Doddridge and 34 more | 4 hr |
| Apr 28, 5:00 PM EDT | Severe Thunderstorm Watch | SPC | Barbour, Boone, Braxton, Calhoun, Clay, Doddridge and 34 more | 4 hr |
Nearby
Tornado Watches in Pennsylvania, 2002Tornado Watches in West Virginia, 2002Every tornado watch in 2002
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.