Alert archive / Illinois / Tornado Watches in 2010

Tornado Watch 97

April 24, 201051 counties in Illinois; 13 counties in Missouri

The Storm Prediction Center issued this tornado watch at Apr 24, 2010, 3:20 PM CDT for 51 counties in Illinois; 13 counties in Missouri. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 24, 2010, 3:20 PM CDT (20:20 UTC)
Expired
Apr 24, 2010, 10:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
70 kt
All 64 counties

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Fayette County, IL, Fulton County, IL, Greene County, IL, Jasper County, IL, Jersey County, IL, Knox County, IL, Lawrence County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Marshall County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Richland County, IL, Saint Clair County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Washington County, IL, Woodford County, IL, City of Saint Louis, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO

The radar

The Lincoln radar (KILX), 98 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
50%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
70%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
60%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 24, 3:31 PM CDTSevere Thunderstorm WarningLSXFranklin, Jefferson, Sainte Genevieve, Saint Francois, Saint Louis, Washington44 min
Apr 24, 3:59 PM CDTTornado WarningLSXFranklin, Jefferson, Saint Louis31 min
Apr 24, 4:20 PM CDTSevere Thunderstorm WarningLSXMonroe25 min
Apr 24, 4:25 PM CDTTornado WarningLSXMadison, Saint Clair35 min
Apr 24, 4:34 PM CDTSevere Thunderstorm WarningLSXMonroe, Randolph41 min
Apr 24, 4:43 PM CDTTornado WarningLSXJersey, Madison32 min
Apr 24, 4:53 PM CDTSevere Thunderstorm WarningLSXBoone, Callaway, Franklin, Gasconade, Montgomery, Osage and 1 more52 min
Apr 24, 5:03 PM CDTTornado WarningLSXBond, Jersey, Macoupin, Madison, Montgomery57 min
Apr 24, 5:09 PM CDTTornado WarningLSXGasconade, Lincoln, Montgomery, Warren51 min
Apr 24, 5:14 PM CDTSevere Thunderstorm WarningLSXMonroe, Saint Clair36 min
Apr 24, 5:34 PM CDTSevere Thunderstorm WarningLSXAudrain, Callaway, Montgomery, Pike, Ralls41 min
Apr 24, 5:51 PM CDTSevere Thunderstorm WarningLSXLincoln, Montgomery, Pike, Warren24 min
Apr 24, 5:54 PM CDTTornado WarningILXChristian, Sangamon51 min
Apr 24, 5:57 PM CDTTornado WarningLSXMacoupin, Montgomery38 min
Apr 24, 6:13 PM CDTSevere Thunderstorm WarningLSXAudrain, Monroe, Pike, Ralls47 min
Apr 24, 6:46 PM CDTTornado WarningILXChristian, Sangamon34 min
Apr 24, 6:53 PM CDTSevere Thunderstorm WarningLSXFayette, Marion18 min
Apr 24, 7:00 PM CDTSevere Thunderstorm WarningILXClay45 min
Apr 24, 7:18 PM CDTSevere Thunderstorm WarningLSXBond, Fayette, Montgomery27 min
Apr 24, 7:36 PM CDTFlash Flood WarningLSXAudrain, Boone, Callaway, Cole, Marion, Moniteau and 5 more6 hr
Apr 24, 7:40 PM CDTSevere Thunderstorm WarningILXClay, Jasper, Richland35 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, 8.3 hours before the alert went out and 145 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 2010-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 494 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 2010-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.1939587897117Sfc1 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
494 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
601 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 23, 7:06 PM CDTTornado WatchSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 4 more5 hr
Apr 24, 7:35 AM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more55 min
Apr 24, 11:08 AM CDTMesoscale DiscussionSPCMonroe67 min
Apr 24, 11:31 AM CDTTornado Watch PDSSPCAlexander, Franklin, Jackson, Johnson, Massac, Perry and 6 more8 hr
Apr 24, 1:17 PM CDTTornado Watch PDSSPCEdwards, Gallatin, Hamilton, Hardin, Jefferson, Wabash and 2 more8 hr
Apr 24, 2:01 PM CDTMesoscale DiscussionSPCAlexander, Hardin, Massac, Pope, Pulaski89 min
Apr 24, 2:52 PM CDTMesoscale DiscussionSPCBond, Clinton, Fayette, Jersey, Madison, Marion and 4 more53 min
Apr 24, 5:14 PM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 41 more61 min
Apr 24, 5:48 PM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 11 more57 min
Apr 23, 10:03 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Bates, Buchanan, Caldwell, Cass and 12 more27 min
Apr 23, 10:58 PM CDTTornado WatchSPCAndrew, Atchison, Buchanan, Caldwell, Carroll, Clay and 15 more5 hr
Apr 23, 11:40 PM CDTMesoscale DiscussionSPCDunklin, Pemiscot65 min
Apr 24, 2:44 AM CDTMesoscale DiscussionSPCDunklin, Pemiscot91 min
Apr 24, 3:15 AM CDTMesoscale DiscussionSPCCaldwell, Carroll, Daviess, Grundy, Livingston, Mercer and 1 more30 min
Apr 24, 6:00 AM CDTTornado Watch PDSSPCDunklin, Pemiscot6 hr
Apr 24, 9:31 AM CDTMesoscale DiscussionSPCDunklin, Pemiscot59 min
Apr 24, 1:29 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Gentry, Harrison, Holt, Mercer and 2 more91 min
Apr 24, 1:52 PM CDTMesoscale DiscussionSPCCamden, Christian, Crawford, Dallas, Dent, Douglas and 14 more53 min

Nearby

Tornado Watches in Illinois, 2010Tornado Watches in Missouri, 2010Every tornado watch in 2010

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.