Alert archive / Illinois / Severe Thunderstorm Watches in 2014

Severe Thunderstorm Watch 166

May 21, 201416 counties in Illinois

The Storm Prediction Center issued this severe thunderstorm watch at May 21, 2014, 2:35 PM CDT for 16 counties in Illinois. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
May 21, 2014, 2:35 PM CDT (19:35 UTC)
Expired
May 21, 2014, 7:33 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Champaign County, IL, Clark County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Logan County, IL, Macon County, IL, McLean County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 36 km from the middle of the area, began a volume at 19:39 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
50%
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
40%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 21, 2:48 PM CDTSevere Thunderstorm WarningILXDeWitt, McLean, Piatt57 min
May 21, 2:58 PM CDTSevere Thunderstorm WarningILXVermilion47 min
May 21, 3:21 PM CDTSevere Thunderstorm WarningILXChampaign, Douglas, Piatt54 min
May 21, 3:27 PM CDTSevere Thunderstorm WarningILXChampaign63 min
May 21, 3:58 PM CDTSevere Thunderstorm WarningILXChampaign, Coles, Douglas, Edgar47 min
May 21, 4:01 PM CDTSevere Thunderstorm WarningILXChampaign, Edgar, Vermilion44 min
May 21, 4:11 PM CDTSevere Thunderstorm WarningILXVermilion64 min
May 21, 4:41 PM CDTSevere Thunderstorm WarningILXColes, Douglas, Edgar64 min
May 21, 4:54 PM CDTSevere Thunderstorm WarningILXChampaign, Piatt66 min
May 21, 5:23 PM CDTFlash Flood WarningILXChampaign, Piatt6 hr
May 21, 5:57 PM CDTSevere Thunderstorm WarningILXChampaign48 min
May 21, 6:28 PM CDTSevere Thunderstorm WarningILXChampaign, Douglas, Edgar, Vermilion62 min
May 21, 7:10 PM CDTSevere Thunderstorm WarningILXChampaign, Vermilion65 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, 7.6 hours before the alert went out and 36 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 2014-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 806 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 2014-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 156 square meters per square second.193958Sfc1 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
806 J/kg
Mixed-layer CIN
-144 J/kg
Mixed-layer LCL
1032 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
156 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 8:06 PM CDTMesoscale DiscussionSPCDeKalb, DuPage, Grundy, Kane, Kankakee, Kendall and 1 more84 min
May 20, 9:56 PM CDTMesoscale DiscussionSPCCarroll, DeKalb, DuPage, Jo Daviess, Kane, Kendall and 4 more94 min
May 20, 11:23 PM CDTMesoscale DiscussionSPCCook, Lake97 min
May 21, 1:27 AM CDTMesoscale DiscussionSPCBureau, Carroll, Cook, DeKalb, DuPage, Grundy and 17 more93 min
May 21, 11:54 AM CDTMesoscale DiscussionSPCIroquois, Vermilion3 hr
May 21, 1:40 PM CDTMesoscale DiscussionSPCAdams, Brown, Cass, Champaign, Christian, Clark and 27 more2 hr
May 21, 3:12 PM CDTMesoscale DiscussionSPCBond, Calhoun, Champaign, Christian, Clark, Clay and 44 more2 hr
May 21, 5:03 PM CDTMesoscale DiscussionSPCEdwards, Franklin, Hamilton, Jefferson, Wabash, Washington and 2 more87 min
May 21, 5:28 PM CDTSevere Thunderstorm WatchSPCEdwards, Franklin, Gallatin, Hamilton, Hardin, Jefferson and 7 more13 hr
May 21, 6:50 PM CDTMesoscale DiscussionSPCChampaign, Clark, Douglas, Edgar, Vermilion85 min

Nearby

Severe Thunderstorm Watches in Illinois, 2014Every severe thunderstorm watch in 2014

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.