Alert archive / Iowa / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 284

June 21, 20166 counties in Illinois; 40 counties in Iowa

The Storm Prediction Center issued this severe thunderstorm watch at Jun 21, 2016, 11:18 PM CDT for 6 counties in Illinois; 40 counties in Iowa. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jun 21, 2016, 11:18 PM CDT (04:18 UTC)
Expired
Jun 22, 2016, 5:36 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 46 counties

Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Calhoun County, IA, Cedar County, IA, Cerro Gordo County, IA, Des Moines County, IA, Emmet County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Henry County, IA, Humboldt County, IA, Iowa County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Kossuth County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Marshall County, IA, Muscatine County, IA, Palo Alto County, IA, Pocahontas County, IA, Poweshiek County, IA, Sac County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Washington County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Hancock County, IL, Henderson County, IL, McDonough County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL

The radar

The Des Moines radar (KDMX), 67 km from the middle of the area, began a volume at 04:18 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
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 21, 11:20 PM CDTSevere Thunderstorm WarningDMXCerro Gordo, Hancock, Kossuth, Winnebago, Worth40 min
Jun 22, 12:03 AM CDTFlash Flood WarningDMXCerro Gordo, Hancock, Kossuth, Winnebago, Worth6 hr
Jun 22, 12:53 AM CDTFlash Flood WarningDMXBlack Hawk, Bremer, Butler, Grundy6 hr
Jun 22, 1:37 AM CDTFlash Flood WarningDVNBenton, Iowa, Johnson, Linn6 hr
Jun 22, 2:02 AM CDTSevere Thunderstorm WarningDMXEmmet, Humboldt, Kossuth, Palo Alto, Pocahontas43 min
Jun 22, 2:25 AM CDTSevere Thunderstorm WarningDMXCerro Gordo, Hancock, Kossuth, Winnebago50 min
Jun 22, 2:38 AM CDTFlash Flood WarningDMXTama6 hr
Jun 22, 2:57 AM CDTSevere Thunderstorm WarningDMXFranklin, Hamilton, Hancock, Hardin, Humboldt, Webster and 1 more48 min
Jun 22, 3:02 AM CDTSevere Thunderstorm WarningDVNMercer, Rock Island43 min
Jun 22, 3:22 AM CDTSevere Thunderstorm WarningDVNHenderson, Mercer, Warren53 min
Jun 22, 3:48 AM CDTSevere Thunderstorm WarningDVNWarren42 min
Jun 22, 4:18 AM CDTFlash Flood WarningDVNJohnson, Louisa, Muscatine, Washington6 hr

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 00:00Z, 4.3 hours before the alert went out and 234 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, Davenport, at 00:00Z on 2016-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 00:00Z on 2016-06-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2283 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
128 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
Jun 21, 10:28 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Christian, Fulton and 18 more2 hr
Jun 22, 2:31 AM CDTMesoscale DiscussionSPCMercer119 min
Jun 22, 4:00 AM CDTMesoscale DiscussionSPCBrown, Cass, Christian, DeWitt, Fulton, Hancock and 14 more2 hr
Jun 22, 4:25 AM CDTSevere Thunderstorm WatchSPCCass, Champaign, Christian, Coles, Cumberland, DeWitt and 15 more3 hr
Jun 22, 3:38 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Champaign, Cook, DeKalb and 32 more97 min
Jun 22, 6:11 PM CDTTornado WatchSPCBoone, Bureau, Carroll, Champaign, Cook, DeKalb and 28 more7 hr
Jun 21, 9:49 PM CDTMesoscale DiscussionSPCBuena Vista, Cherokee, Clay, Crawford, Dickinson, Ida and 8 more26 min
Jun 21, 10:21 PM CDTSevere Thunderstorm WatchSPCBuena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 6 more7 hr
Jun 22, 4:43 AM CDTMesoscale DiscussionSPCClay, Dickinson, Lyon, O'Brien, Osceola, Sioux92 min

Nearby

Severe Thunderstorm Watches in Iowa, 2016Severe Thunderstorm Watches in Illinois, 2016Every 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.