Alert archive / Ohio / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 429
The Storm Prediction Center issued this severe thunderstorm watch at Aug 11, 2021, 4:57 PM EDT for 19 counties in Ohio. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 11, 2021, 4:57 PM EDT (20:57 UTC)
- Expired
- Aug 11, 2021, 7:52 PM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
Counties Ashtabula County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Geauga County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Lake County, OH, Mahoning County, OH, Monroe County, OH, Muskingum County, OH, Noble County, OH, Portage County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH
The radar
The Cleveland radar (KCLE), 75 km from the middle of the area, began a volume at 21:02 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
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 5:17 PM EDT | Severe Thunderstorm Warning | CLE | Cuyahoga, Geauga, Lake, Portage, Summit | 58 min |
| Aug 11, 5:36 PM EDT | Severe Thunderstorm Warning | CLE | Mahoning, Medina, Portage, Stark, Summit, Wayne | 69 min |
| Aug 11, 5:41 PM EDT | Severe Thunderstorm Warning | CLE | Ashtabula, Geauga, Lake, Portage, Trumbull | 79 min |
| Aug 11, 6:09 PM EDT | Severe Thunderstorm Warning | CLE | Ashtabula | 75 min |
| Aug 11, 6:12 PM EDT | Severe Thunderstorm Warning | CLE | Mahoning, Portage, Trumbull | 69 min |
| Aug 11, 6:23 PM EDT | Severe Thunderstorm Warning | PBZ | Guernsey, Muskingum, Noble | 37 min |
| Aug 11, 6:51 PM EDT | Severe Thunderstorm Warning | PBZ | Monroe, Noble | 24 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, 9.0 hours before the alert went out and 124 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
- 267 J/kg
- Mixed-layer CIN
- -243 J/kg
- Mixed-layer LCL
- 1321 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 131 m²/s²
- 0-3 km storm-relative helicity
- 188 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
138 WWUS20 KWNS 112051 SEL9 SPC WW 112051 OHZ000-PAZ000-LEZ000-120100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 429 NWS Storm Prediction Center Norman OK 455 PM EDT Wed Aug 11 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Ohio Extreme northwestern Pennsylvania Lake Erie * Effective this Wednesday afternoon and evening from 455 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...A line of storms with a history of wind damage will likely persist into eastern Ohio and northwestern Pennsylvania before weakening by late evening. Damaging winds of 60-70 mph and isolated, marginally severe hail around 1 inch diameter will be the main threats. The severe thunderstorm watch area is approximately along and 40 statute miles east and west of a line from 40 miles west northwest of Erie PA to 25 miles east southeast of Zanesville OH. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). 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 424...WW 425...WW 426...WW 427...WW 428... 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 550. Mean storm motion vector 27035. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 8:12 PM EDT | Mesoscale Discussion | SPC | Williams | 63 min |
| Aug 10, 8:38 PM EDT | Severe Thunderstorm Watch | SPC | Williams | 5 hr |
| Aug 10, 10:57 PM EDT | Mesoscale Discussion | SPC | Defiance, Fulton, Henry, Lucas, Paulding, Putnam and 2 more | 93 min |
| Aug 11, 9:31 AM EDT | Mesoscale Discussion | SPC | Ashland, Ashtabula, Carroll, Columbiana, Coshocton, Crawford and 19 more | 89 min |
| Aug 11, 10:52 AM EDT | Mesoscale Discussion | SPC | Defiance, Paulding, Williams | 83 min |
| Aug 11, 11:50 AM EDT | Mesoscale Discussion | SPC | Carroll, Columbiana, Harrison, Jefferson, Mahoning, Trumbull | 115 min |
| Aug 11, 11:50 AM EDT | Severe Thunderstorm Watch | SPC | Allen, Defiance, Fulton, Henry, Paulding, Putnam and 2 more | 4 hr |
| Aug 11, 1:26 PM EDT | Mesoscale Discussion | SPC | Allen, Defiance, Fulton, Henry, Paulding, Putnam and 2 more | 94 min |
| Aug 11, 2:12 PM EDT | Mesoscale Discussion | SPC | Allen, Ashland, Auglaize, Champaign, Crawford, Delaware and 26 more | 93 min |
| Aug 11, 2:32 PM EDT | Severe Thunderstorm Watch | SPC | Ashland, Auglaize, Champaign, Clark, Crawford, Cuyahoga and 28 more | 4 hr |
| Aug 11, 4:24 PM EDT | Mesoscale Discussion | SPC | Athens, Belmont, Carroll, Clinton, Columbiana, Coshocton and 31 more | 96 min |
| Aug 11, 1:01 PM EDT | Mesoscale Discussion | SPC | Berkeley, Grant, Hampshire, Hardy, Jefferson, Mineral and 3 more | 89 min |
| Aug 11, 2:02 PM EDT | Severe Thunderstorm Watch | SPC | Berkeley, Hampshire, Hardy, Jefferson, Mineral, Morgan | 6 hr |
Nearby
Severe 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.