Alert archive / Ohio / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 804

August 24, 20115 states

The Storm Prediction Center issued this severe thunderstorm watch at Aug 24, 2011, 9:18 PM EDT for 5 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Aug 24, 2011, 9:18 PM EDT (01:18 UTC)
Expired: Aug 25, 2011, 3:39 AM EDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 65 kt

All 96 counties

Bartholomew County, IN, Brown County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Fayette County, IN, Franklin County, IN, Greene County, IN, Henry County, IN, Jackson County, IN, Jennings County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Monroe County, IN, Ohio County, IN, Randolph County, IN, Ripley County, IN, Rush County, IN, Shelby County, IN, Switzerland County, IN, Union County, IN, Wayne County, IN, Boone County, KY, Campbell County, KY, Kenton County, KY, Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Livingston County, NY, Monroe County, NY, Niagara County, NY, Ontario County, NY, Orleans County, NY, Wayne County, NY, Wyoming County, NY, Ashland County, OH, Ashtabula County, OH, Auglaize County, OH, Brown County, OH, Butler County, OH, Champaign County, OH, Clark County, OH, Clermont County, OH, Clinton County, OH, Crawford County, OH, Cuyahoga County, OH, Darke County, OH, Delaware County, OH, Erie County, OH, Fairfield County, OH, Fayette County, OH, Franklin County, OH, Geauga County, OH, Greene County, OH, Hamilton County, OH, Hancock County, OH, Hardin County, OH, Highland County, OH, Holmes County, OH, Huron County, OH, Knox County, OH, Lake County, OH, Licking County, OH, Logan County, OH, Lorain County, OH, Lucas County, OH, Madison County, OH, Mahoning County, OH, Marion County, OH, Medina County, OH, Mercer County, OH, Miami County, OH, Montgomery County, OH, Morrow County, OH, Ottawa County, OH, Pickaway County, OH, Portage County, OH, Preble County, OH, Richland County, OH, Ross County, OH, Sandusky County, OH, Seneca County, OH, Shelby County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Union County, OH, Warren County, OH, Wayne County, OH, Wood County, OH, Wyandot County, OH, Crawford County, PA, Erie County, PA

The radar

The Cincinnati radar (KILN), 139 km from the middle of the area, began a volume at 01:21 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: 10%
Ten or more severe wind reports: 95%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

23 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Aug 24, 9:56 PM EDT	Severe Thunderstorm Warning	BUF	Erie, Niagara, Orleans	64 min
Aug 24, 10:11 PM EDT	Severe Thunderstorm Warning	CLE	Lucas, Wood	64 min
Aug 24, 10:34 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus, Chautauqua, Erie	56 min
Aug 24, 10:45 PM EDT	Severe Thunderstorm Warning	BUF	Erie	49 min
Aug 24, 10:54 PM EDT	Severe Thunderstorm Warning	BUF	Genesee, Monroe, Orleans	41 min
Aug 24, 11:04 PM EDT	Severe Thunderstorm Warning	CLE	Ottawa, Sandusky	41 min
Aug 24, 11:07 PM EDT	Severe Thunderstorm Warning	CLE	Hancock	53 min
Aug 24, 11:14 PM EDT	Severe Thunderstorm Warning	CLE	Seneca, Wood	61 min
Aug 24, 11:30 PM EDT	Severe Thunderstorm Warning	CLE	Ashtabula, Geauga, Lake	75 min
Aug 24, 11:31 PM EDT	Severe Thunderstorm Warning	CLE	Wyandot	44 min
Aug 24, 11:35 PM EDT	Severe Thunderstorm Warning	CLE	Erie, Huron	40 min
Aug 24, 11:49 PM EDT	Severe Thunderstorm Warning	IND	Hamilton, Hancock, Henry, Madison, Marion, Rush	41 min
Aug 24, 11:49 PM EDT	Severe Thunderstorm Warning	CLE	Cuyahoga, Lorain, Medina	71 min
Aug 24, 11:53 PM EDT	Severe Thunderstorm Warning	CLE	Crawford, Marion	42 min
Aug 25, 12:01 AM EDT	Severe Thunderstorm Warning	CLE	Ashland, Richland	59 min
Aug 25, 12:26 AM EDT	Severe Thunderstorm Warning	CLE	Geauga, Portage, Summit, Wayne	79 min
Aug 25, 12:41 AM EDT	Severe Thunderstorm Warning	CLE	Ashtabula, Geauga, Lake	79 min
Aug 25, 1:09 AM EDT	Severe Thunderstorm Warning	CLE	Mahoning, Trumbull	66 min
Aug 25, 1:12 AM EDT	Severe Thunderstorm Warning	IND	Decatur, Rush	18 min
Aug 25, 1:12 AM EDT	Severe Thunderstorm Warning	CLE	Stark	48 min
Aug 25, 1:27 AM EDT	Tornado Warning	CLE	Trumbull	25 min
Aug 25, 1:34 AM EDT	Severe Thunderstorm Warning	ILN	Delaware, Logan, Union	26 min
Aug 25, 3:34 AM EDT	Severe Thunderstorm Warning	ILN	Clark, Fayette, Greene, Madison, Pickaway	26 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 00:00Z, 1.3 hours before the alert went out and 137 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 3854 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 1316 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 184 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 15.7

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 24, 9:56 PM EDT	Mesoscale Discussion	SPC	Adams, Allen, Bartholomew, Blackford, Boone, Brown and 66 more	94 min
Aug 24, 11:48 PM EDT	Mesoscale Discussion	SPC	Dearborn, Franklin, Union	87 min
Aug 25, 2:31 AM EDT	Mesoscale Discussion	SPC	Dearborn, Franklin, Ohio	119 min
Aug 25, 12:42 AM EDT	Severe Thunderstorm Watch	SPC	Steuben	5 hr
Aug 24, 10:27 PM EDT	Tornado Watch	SPC	Ashland, Ashtabula, Crawford, Cuyahoga, Erie, Geauga and 22 more	5 hr

Nearby

Severe Thunderstorm Watches in Ohio, 2011 Severe Thunderstorm Watches in Indiana, 2011 Severe Thunderstorm Watches in New York, 2011 Every 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.