Alert archive / Illinois / Severe Thunderstorm Watches in 2014

Severe Thunderstorm Watch 12

February 20, 201417 counties in Illinois

The Storm Prediction Center issued this severe thunderstorm watch at Feb 20, 2014, 3:50 PM CST for 17 counties in Illinois. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Feb 20, 2014, 3:50 PM CST (21:50 UTC)
Expired
Feb 20, 2014, 4:46 PM CST
In force
56 min
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt

Counties Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Jasper County, IL, Lawrence County, IL, Logan County, IL, Macon County, IL, Moultrie County, IL, Piatt County, IL, Richland County, IL, Shelby County, IL

The radar

The Lincoln radar (KILX), 124 km from the middle of the area, began a volume at 21:51 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
10%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Feb 20, 4:01 PM CSTSevere Thunderstorm WarningILXChristian, Coles, Douglas, Macon, Moultrie, Piatt and 1 more59 min
Feb 20, 4:08 PM CSTTornado WarningILXDeWitt, Logan, Macon, Sangamon22 min
Feb 20, 4:11 PM CSTTornado WarningILXChristian, Shelby34 min
Feb 20, 4:40 PM CSTTornado WarningILXColes, Douglas, Moultrie, Piatt, Shelby35 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, 9.8 hours before the alert went out and 84 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 2014-02-20Temperature 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, Lincoln, IL at 12:00Z on 2014-02-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 582 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
507 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
582 m²/s²
0-3 km storm-relative helicity
576 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
Feb 20, 11:34 AM CSTMesoscale DiscussionSPCBrown, Calhoun, Cass, Greene, Jersey, Macoupin and 3 more116 min
Feb 20, 1:36 PM CSTSevere Thunderstorm WatchSPCAdams, Bond, Brown, Calhoun, Christian, Clinton and 15 more4 hr
Feb 20, 1:45 PM CSTMesoscale DiscussionSPCAlexander, Gallatin, Hardin, Johnson, Massac, Pope and 5 more2 hr
Feb 20, 2:23 PM CSTTornado WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more7 hr
Feb 20, 3:23 PM CSTMesoscale DiscussionSPCBond, Calhoun, Christian, Clark, Clay, Clinton and 25 more97 min
Feb 20, 4:45 PM CSTTornado WatchSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 12 more3 hr
Feb 20, 5:29 PM CSTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 14 more46 min
Feb 20, 5:45 PM CSTTornado WatchSPCBartholomew, Boone, Brown, Carroll, Clark, Clinton and 36 more5 hr

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.