Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2016
Severe Thunderstorm Watch 499
The Storm Prediction Center issued this severe thunderstorm watch at Oct 20, 2016, 3:46 PM EDT for Garrett County, Maryland; 25 counties in Pennsylvania; 5 counties in West Virginia. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 20, 2016, 3:46 PM EDT (19:46 UTC)
- Expired
- Oct 20, 2016, 11:00 PM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 31 counties
Garrett County, MD, Allegheny County, PA, Armstrong County, PA, Bedford County, PA, Blair County, PA, Butler 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, Forest County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Lycoming County, PA, McKean County, PA, Potter County, PA, Somerset County, PA, Tioga County, PA, Washington County, PA, Westmoreland County, PA, Marion County, WV, Marshall County, WV, Monongalia County, WV, Preston County, WV, Wetzel County, WV
The radar
The Pittsburgh radar (KPBZ), 69 km from the middle of the area, began a volume at 19:48 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 30%
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 20, 4:19 PM EDT | Severe Thunderstorm Warning | PBZ | Wetzel | 41 min |
| Oct 20, 4:51 PM EDT | Severe Thunderstorm Warning | PBZ | Greene | 39 min |
| Oct 20, 4:58 PM EDT | Severe Thunderstorm Warning | CTP | Clearfield | 62 min |
| Oct 20, 5:27 PM EDT | Severe Thunderstorm Warning | PBZ | Fayette, Greene, Washington | 25 min |
| Oct 20, 6:24 PM EDT | Severe Thunderstorm Warning | PBZ | Indiana, Jefferson | 36 min |
| Oct 20, 6:42 PM EDT | Severe Thunderstorm Warning | PBZ | Fayette, Westmoreland | 33 min |
| Oct 20, 7:04 PM EDT | Severe Thunderstorm Warning | CTP | Bedford, Cambria, Somerset | 56 min |
| Oct 20, 8:15 PM EDT | Severe Thunderstorm Warning | PBZ | Garrett | 45 min |
| Oct 20, 10:10 PM EDT | Severe Thunderstorm Warning | CTP | Centre, Clinton, Lycoming | 65 min |
| Oct 20, 10:42 PM EDT | Severe Thunderstorm Warning | CTP | Lycoming, Sullivan, Tioga | 52 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 (KAGC), launched 12:00Z, 7.8 hours before the alert went out and 59 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
- 45 J/kg
- Mixed-layer CIN
- -141 J/kg
- Mixed-layer LCL
- 1215 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 278 m²/s²
- 0-3 km storm-relative helicity
- 264 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 |
|---|---|---|---|---|
| Oct 20, 2:28 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 3 hr |
| Oct 20, 6:58 PM EDT | Mesoscale Discussion | SPC | Garrett | 92 min |
| Oct 20, 4:42 PM EDT | Mesoscale Discussion | SPC | Boone, Braxton, Cabell, Calhoun, Clay, Fayette and 14 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Pennsylvania, 2016Severe Thunderstorm Watches in West Virginia, 2016Severe Thunderstorm Watches in Maryland, 2016Every severe thunderstorm watch in 2016
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.