Alert archive / Indiana / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 568

August 9, 201214 counties in Illinois; 21 counties in Indiana

The Storm Prediction Center issued this severe thunderstorm watch at Aug 9, 2012, 4:02 PM CDT for 14 counties in Illinois; 21 counties in Indiana. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Aug 9, 2012, 4:02 PM CDT (21:02 UTC)
Expired
Aug 9, 2012, 7:46 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 35 counties

Champaign County, IL, Coles County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Iroquois County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, McLean County, IL, Moultrie County, IL, Piatt County, IL, Vermilion County, IL, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Fountain County, IN, Hamilton County, IN, Hendricks County, IN, Howard County, IN, Jasper County, IN, Marion County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Parke County, IN, Putnam County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Warren County, IN, White County, IN

The radar

The Chicago radar (KLOT), 127 km from the middle of the area, began a volume at 21:05 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
30%
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
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 9, 4:20 PM CDTSevere Thunderstorm WarningILXDeWitt, McLean, Piatt38 min
Aug 9, 4:31 PM CDTSevere Thunderstorm WarningLOTFord, Livingston53 min
Aug 9, 4:35 PM CDTSevere Thunderstorm WarningLOTLaSalle, Livingston55 min
Aug 9, 5:17 PM CDTSevere Thunderstorm WarningLOTLivingston43 min
Aug 9, 5:44 PM CDTSevere Thunderstorm WarningLOTLake, Newton61 min
Aug 9, 5:45 PM CDTSevere Thunderstorm WarningILXChampaign, Edgar, Vermilion60 min
Aug 9, 5:46 PM CDTSevere Thunderstorm WarningINDFountain, Montgomery, Parke44 min
Aug 9, 6:02 PM CDTTornado WarningINDFountain, Montgomery, Parke, Putnam28 min
Aug 9, 6:13 PM CDTSevere Thunderstorm WarningLOTFord, Iroquois, Kankakee, Livingston62 min
Aug 9, 6:17 PM CDTSevere Thunderstorm WarningILXChampaign, Douglas, Edgar, Vermilion58 min
Aug 9, 6:18 PM CDTSevere Thunderstorm WarningINDFountain, Montgomery, Tippecanoe42 min
Aug 9, 6:27 PM CDTSevere Thunderstorm WarningINDMontgomery, Putnam33 min
Aug 9, 6:36 PM CDTSevere Thunderstorm WarningLOTIroquois37 min
Aug 9, 6:55 PM CDTTornado WarningLOTJasper, Newton50 min
Aug 9, 6:56 PM CDTSevere Thunderstorm WarningINDBoone, Hendricks, Montgomery, Putnam34 min
Aug 9, 6:57 PM CDTSevere Thunderstorm WarningLOTIroquois63 min
Aug 9, 6:58 PM CDTSevere Thunderstorm WarningINDClinton, Montgomery, Tippecanoe32 min
Aug 9, 7:23 PM CDTSevere Thunderstorm WarningILXVermilion52 min
Aug 9, 7:25 PM CDTSevere Thunderstorm WarningIWXWhite50 min
Aug 9, 7:28 PM CDTSevere Thunderstorm WarningINDBoone, Hendricks32 min
Aug 9, 7:30 PM CDTSevere Thunderstorm WarningINDCarroll, Clinton, Tippecanoe30 min
Aug 9, 7:36 PM CDTTornado WarningIWXWhite39 min
Aug 9, 7:41 PM CDTSevere Thunderstorm WarningLOTIroquois34 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

Lincoln, IL (KILX), launched 12:00Z, 9.0 hours before the alert went out and 78 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, Lincoln, IL at 12:00Z on 2012-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 396 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, Lincoln, IL at 12:00Z on 2012-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
396 J/kg
Mixed-layer CIN
-236 J/kg
Mixed-layer LCL
1480 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 3:16 PM CDTMesoscale DiscussionSPCChampaign, DeWitt, Douglas, Edgar, Ford, Iroquois and 6 more89 min
Aug 9, 5:11 PM CDTMesoscale DiscussionSPCHancock, Henderson, Henry, Knox, McDonough, Mercer and 4 more94 min
Aug 9, 3:18 PM CDTMesoscale DiscussionSPCOhio, Switzerland57 min

Nearby

Severe Thunderstorm Watches in Indiana, 2012Severe Thunderstorm Watches in Illinois, 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.