Alert archive / Ohio / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 567

August 9, 20124 states

The Storm Prediction Center issued this severe thunderstorm watch at Aug 9, 2012, 4:41 PM EDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Aug 9, 2012, 4:41 PM EDT (20:41 UTC)
Expired
Aug 9, 2012, 10:00 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 59 counties

Bracken County, KY, Grant County, KY, Lewis County, KY, Mason County, KY, Owen County, KY, Pendleton County, KY, Robertson County, KY, Adams County, OH, Athens County, OH, Belmont County, OH, Brown County, OH, Carroll County, OH, Clermont County, OH, Columbiana County, OH, Coshocton County, OH, Fairfield County, OH, Fayette County, OH, Guernsey County, OH, Harrison County, OH, Highland County, OH, Hocking County, OH, Jackson County, OH, Jefferson County, OH, Licking County, OH, Meigs County, OH, Monroe County, OH, Morgan County, OH, Muskingum County, OH, Noble County, OH, Perry County, OH, Pickaway County, OH, Pike County, OH, Ross County, OH, Scioto County, OH, Tuscarawas County, OH, Vinton County, OH, Washington County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Clarion County, PA, Forest County, PA, Greene County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Washington County, PA, Brooke County, WV, Hancock County, WV, Marion County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Pleasants County, WV, Tyler County, WV, Wetzel County, WV, Wood County, WV

The radar

The Cincinnati radar (KILN), 110 km from the middle of the area, began a volume at 20:43 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
10%
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
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 9, 4:55 PM EDTFlash Flood WarningILNBoone, Campbell, Carroll, Gallatin, Grant, Kenton and 1 more81 min
Aug 9, 4:57 PM EDTSevere Thunderstorm WarningILNBracken, Pendleton, Robertson48 min
Aug 9, 5:08 PM EDTSevere Thunderstorm WarningPBZCoshocton, Muskingum52 min
Aug 9, 5:29 PM EDTSevere Thunderstorm WarningPBZLawrence, Mercer61 min
Aug 9, 5:41 PM EDTSevere Thunderstorm WarningILNBracken, Mason, Pendleton, Robertson33 min
Aug 9, 5:49 PM EDTSevere Thunderstorm WarningILNClinton, Fayette41 min
Aug 9, 6:05 PM EDTSevere Thunderstorm WarningPBZGuernsey, Muskingum55 min
Aug 9, 6:05 PM EDTSevere Thunderstorm WarningPBZGuernsey, Muskingum, Noble40 min
Aug 9, 6:10 PM EDTSevere Thunderstorm WarningILNLewis, Mason50 min
Aug 9, 6:41 PM EDTSevere Thunderstorm WarningPBZVenango34 min
Aug 9, 6:43 PM EDTSevere Thunderstorm WarningPBZCarroll, Columbiana32 min
Aug 9, 6:47 PM EDTSevere Thunderstorm WarningRLXMorgan, Perry43 min
Aug 9, 6:48 PM EDTSevere Thunderstorm WarningPBZCarroll, Guernsey, Harrison, Tuscarawas42 min
Aug 9, 6:52 PM EDTSevere Thunderstorm WarningILNHocking38 min
Aug 9, 7:00 PM EDTSevere Thunderstorm WarningPBZButler, Lawrence, Mercer45 min
Aug 9, 7:05 PM EDTSevere Thunderstorm WarningRLXMorgan32 min
Aug 9, 7:15 PM EDTSevere Thunderstorm WarningPBZArmstrong, Butler, Clarion, Forest, Jefferson, Venango60 min
Aug 9, 7:49 PM EDTSevere Thunderstorm WarningRLXAthens, Meigs, Vinton26 min
Aug 9, 8:12 PM EDTSevere Thunderstorm WarningILNDelaware, Franklin, Licking33 min
Aug 9, 8:51 PM EDTSevere Thunderstorm WarningPBZAllegheny, Washington24 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, 8.7 hours before the alert went out and 108 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-pSkew-T log-p diagram, Cncnati-Daytn, OH at 12:00Z on 2012-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 946 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cncnati-Daytn, OH at 12:00Z on 2012-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
946 J/kg
Mixed-layer CIN
-111 J/kg
Mixed-layer LCL
1085 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 4:18 PM EDTMesoscale DiscussionSPCBath, Boone, Bourbon, Bracken, Campbell, Carroll and 16 more57 min
Aug 9, 12:46 PM EDTMesoscale DiscussionSPCBradford, Cameron, Lycoming, Potter, Sullivan, Susquehanna and 2 more89 min

Nearby

Severe Thunderstorm Watches in Ohio, 2012Severe Thunderstorm Watches in Pennsylvania, 2012Severe Thunderstorm Watches in West Virginia, 2012Every severe thunderstorm watch in 2012

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.