Alert archive / Illinois / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 412

July 23, 201622 counties in Illinois; 14 counties in Iowa; 12 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Jul 23, 2016, 3:23 PM CDT for 22 counties in Illinois; 14 counties in Iowa; 12 counties in Wisconsin. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jul 23, 2016, 3:23 PM CDT (20:23 UTC)
Expired: Jul 23, 2016, 10:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 48 counties

Benton County, IA, Buchanan County, IA, Cedar County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Muscatine County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Quad Cities radar (KDVN), 64 km from the middle of the area, began a volume at 20:22 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: 5%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 50%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jul 23, 3:52 PM CDT	Severe Thunderstorm Warning	DVN	Buchanan, Delaware, Dubuque, Jones, Linn	53 min
Jul 23, 4:00 PM CDT	Tornado Warning	DVN	Delaware	45 min
Jul 23, 4:04 PM CDT	Flash Flood Warning	DVN	Buchanan	6 hr
Jul 23, 4:13 PM CDT	Severe Thunderstorm Warning	LOT	Boone, McHenry	47 min
Jul 23, 4:22 PM CDT	Flash Flood Warning	DVN	Delaware	6 hr
Jul 23, 4:26 PM CDT	Tornado Warning	DVN	Delaware	20 min
Jul 23, 4:35 PM CDT	Tornado Warning	DVN	Dubuque, Jackson	55 min
Jul 23, 4:38 PM CDT	Severe Thunderstorm Warning	DVN	Jackson, Jones	67 min
Jul 23, 4:40 PM CDT	Flash Flood Warning	DVN	Dubuque, Jackson, Jones	6 hr
Jul 23, 4:58 PM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, McHenry	47 min
Jul 23, 4:59 PM CDT	Severe Thunderstorm Warning	DVN	Jo Daviess	61 min
Jul 23, 5:00 PM CDT	Flash Flood Warning	LOT	Boone, McHenry, Winnebago	6 hr
Jul 23, 5:12 PM CDT	Tornado Warning	DVN	Jackson, Jones	63 min
Jul 23, 5:19 PM CDT	Severe Thunderstorm Warning	MKX	Lafayette	41 min
Jul 23, 5:25 PM CDT	Severe Thunderstorm Warning	LOT	Boone, Winnebago	35 min
Jul 23, 5:28 PM CDT	Severe Thunderstorm Warning	LOT	Kane, McHenry	47 min
Jul 23, 5:52 PM CDT	Severe Thunderstorm Warning	MKX	Green, Lafayette	38 min
Jul 23, 5:55 PM CDT	Severe Thunderstorm Warning	DVN	Jo Daviess, Stephenson	65 min
Jul 23, 6:08 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Clinton, Jackson, Jones	67 min
Jul 23, 6:13 PM CDT	Severe Thunderstorm Warning	LOT	Cook	47 min
Jul 23, 6:30 PM CDT	Severe Thunderstorm Warning	MKX	Green, Rock	30 min
Jul 23, 7:00 PM CDT	Severe Thunderstorm Warning	DVN	Carroll, Whiteside	60 min
Jul 23, 7:33 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	42 min
Jul 23, 8:07 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	53 min
Jul 23, 8:44 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Lee, Ogle	46 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

Davenport, (KDVN), launched 12:00Z, 8.4 hours before the alert went out and 60 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: 2607 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 807 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 83 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.

Issued	Product	Office	Counties	Lasted
Jul 23, 1:06 PM CDT	Mesoscale Discussion	SPC	Boone, McHenry, Winnebago	2 hr
Jul 23, 2:50 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, DeKalb, Jo Daviess, Kane, McHenry and 3 more	25 min
Jul 23, 5:25 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, DeKalb, DuPage, Jo Daviess, Kane and 8 more	2 hr
Jul 23, 8:58 AM CDT	Mesoscale Discussion	SPC	Allamakee, Clayton, Fayette, Howard, Winneshiek	3 hr
Jul 23, 2:08 PM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Buchanan, Cedar, Clayton, Clinton and 8 more	3 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2016 Severe Thunderstorm Watches in Iowa, 2016 Severe Thunderstorm Watches in Wisconsin, 2016 Every severe thunderstorm watch in 2016

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.