Alert archive / Ohio / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 660
The Storm Prediction Center issued this severe thunderstorm watch at Jul 18, 2011, 6:26 PM EDT for 29 counties in Ohio; 25 counties in West Virginia. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 18, 2011, 6:26 PM EDT (22:26 UTC)
- Expired
- Jul 18, 2011, 10:47 PM EDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 54 counties
Adams County, OH, Athens County, OH, Brown County, OH, Champaign County, OH, Clark County, OH, Clinton County, OH, Delaware County, OH, Fairfield County, OH, Fayette County, OH, Franklin County, OH, Gallia County, OH, Greene County, OH, Highland County, OH, Hocking County, OH, Jackson County, OH, Lawrence County, OH, Licking County, OH, Logan County, OH, Madison County, OH, Meigs County, OH, Morgan County, OH, Perry County, OH, Pickaway County, OH, Pike County, OH, Ross County, OH, Scioto County, OH, Union County, OH, Vinton County, OH, Washington County, OH, Barbour County, WV, Braxton County, WV, Cabell County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Gilmer County, WV, Harrison County, WV, Jackson County, WV, Kanawha County, WV, Lewis County, WV, Mason County, WV, Nicholas County, WV, Pleasants County, WV, Pocahontas County, WV, Putnam County, WV, Randolph County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tyler County, WV, Upshur County, WV, Webster County, WV, Wirt County, WV, Wood County, WV
The radar
The Cincinnati radar (KILN), 140 km from the middle of the area, began a volume at 22:28 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
- 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
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 6:56 PM EDT | Severe Thunderstorm Warning | ILN | Fairfield, Hocking | 37 min |
| Jul 18, 7:12 PM EDT | Flash Flood Warning | ILN | Fairfield | 3 hr |
| Jul 18, 7:53 PM EDT | Flash Flood Warning | ILN | Hocking | 112 min |
| Jul 18, 7:58 PM EDT | Flash Flood Warning | RLX | Vinton | 3 hr |
| Jul 18, 8:15 PM EDT | Severe Thunderstorm Warning | RLX | Athens, Jackson, Meigs, Vinton | 60 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
Cncnati-Daytn, OH (KILN), launched 12:00Z, 10.4 hours before the alert went out and 138 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
- 1057 J/kg
- Mixed-layer CIN
- -29 J/kg
- Mixed-layer LCL
- 878 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 9 m²/s²
- 0-3 km storm-relative helicity
- 22 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 1:18 PM EDT | Mesoscale Discussion | SPC | Ashland, Carroll, Columbiana, Coshocton, Crawford, Cuyahoga and 27 more | 117 min |
| Jul 18, 3:57 PM EDT | Severe Thunderstorm Watch | SPC | Ashland, Ashtabula, Belmont, Carroll, Columbiana, Coshocton and 33 more | 6 hr |
| Jul 18, 6:14 PM EDT | Mesoscale Discussion | SPC | Athens, Champaign, Clark, Crawford, Delaware, Fairfield and 27 more | 31 min |
Nearby
Severe Thunderstorm Watches in Ohio, 2011Severe Thunderstorm Watches in West Virginia, 2011Every severe thunderstorm watch in 2011
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.