Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 328
The Storm Prediction Center issued this severe thunderstorm watch at Jun 30, 2021, 12:46 PM EDT for 6 counties in Ohio; 26 counties in Pennsylvania. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 30, 2021, 12:46 PM EDT (16:46 UTC)
- Expired
- Jun 30, 2021, 8:00 PM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 32 counties
Ashtabula County, OH, Geauga County, OH, Mahoning County, OH, Portage County, OH, Stark County, OH, Trumbull County, OH, Bedford County, PA, Blair County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Crawford County, PA, Elk County, PA, Erie County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lycoming County, PA, McKean County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Potter County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, Warren County, PA
The radar
The State College radar (KCCX), 71 km from the middle of the area, began a volume at 16:49 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
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 30, 2:14 PM EDT | Severe Thunderstorm Warning | CTP | Clinton, Lycoming | 50 min |
| Jun 30, 2:25 PM EDT | Severe Thunderstorm Warning | CTP | Cambria | 28 min |
| Jun 30, 3:46 PM EDT | Severe Thunderstorm Warning | CTP | Centre, Montour, Northumberland, Snyder, Union | 44 min |
| Jun 30, 5:24 PM EDT | Severe Thunderstorm Warning | CTP | Franklin, Fulton | 48 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, 4.8 hours before the alert went out and 131 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
- 807 J/kg
- Mixed-layer CIN
- -49 J/kg
- Mixed-layer LCL
- 1240 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 71 m²/s²
- 0-3 km storm-relative helicity
- 66 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.2
The text
As transmitted.
637 WWUS20 KWNS 301643 SEL8 SPC WW 301643 OHZ000-PAZ000-WVZ000-010000- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 328 NWS Storm Prediction Center Norman OK 1245 PM EDT Wed Jun 30 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of East central and northeastern Ohio Western and central Pennsylvania Extreme northern West Virginia * Effective this Wednesday afternoon and evening from 1245 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible SUMMARY...Scattered thunderstorm clusters are expected to develop and spread east-northeastward across eastern Ohio and Pennsylvania through the afternoon and evening, with an attendant threat for damaging winds. The severe thunderstorm watch area is approximately along and 70 statute miles north and south of a line from 20 miles south of Elmira NY to 40 miles south southwest of Akron OH. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 326...WW 327... AVIATION...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 500. Mean storm motion vector 26030. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 30, 11:04 AM EDT | Mesoscale Discussion | SPC | Albany, Allegany, Broome, Cayuga, Chemung, Chenango and 29 more | 116 min |
| Jun 30, 11:47 AM EDT | Severe Thunderstorm Watch | SPC | Albany, Allegany, Broome, Cattaraugus, Cayuga, Chautauqua and 27 more | 7 hr |
| Jun 30, 12:06 PM EDT | Severe Thunderstorm Watch | SPC | Essex | 7 hr |
| Jun 30, 1:52 PM EDT | Mesoscale Discussion | SPC | Fulton, Montgomery, Saratoga, Schenectady, Warren, Washington | 83 min |
| Jun 30, 2:16 PM EDT | Mesoscale Discussion | SPC | Albany, Columbia, Dutchess, Greene, Orange, Putnam and 2 more | 119 min |
| Jun 30, 3:21 PM EDT | Severe Thunderstorm Watch | SPC | Columbia, Dutchess, Greene, Orange, Putnam, Rockland and 3 more | 7 hr |
| Jun 30, 4:48 PM EDT | Mesoscale Discussion | SPC | Albany, Columbia, Delaware, Greene, Schoharie, Sullivan and 1 more | 87 min |
| Jun 30, 6:58 PM EDT | Mesoscale Discussion | SPC | Bronx, Orange, Putnam, Rockland, Westchester | 92 min |
| Jun 30, 11:30 AM EDT | Mesoscale Discussion | SPC | Belmont, Carroll, Columbiana, Coshocton, Guernsey, Harrison and 10 more | 2 hr |
| Jun 30, 3:29 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Bedford, Blair, Cambria, Centre and 16 more | 2 hr |
| Jun 30, 4:41 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Columbia, Cumberland and 17 more | 2 hr |
| Jun 30, 4:51 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Cumberland, Dauphin, Franklin, Lancaster, Lebanon and 3 more | 3 hr |
Nearby
Severe Thunderstorm Watches in Pennsylvania, 2021Severe Thunderstorm Watches in Ohio, 2021Every severe thunderstorm watch in 2021
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.