Alert archive / Illinois / Tornado Watches in 2008

Tornado Watch 393

May 30, 200832 counties in Illinois; 6 counties in Iowa; 6 counties in Missouri

The Storm Prediction Center issued this tornado watch at May 30, 2008, 7:56 AM CDT for 32 counties in Illinois; 6 counties in Iowa; 6 counties in Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 30, 2008, 7:56 AM CDT (12:56 UTC)
Expired
May 30, 2008, 2:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 44 counties

Des Moines County, IA, Henry County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Van Buren County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Cass County, IL, Cook County, IL, DuPage County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Will County, IL, Woodford County, IL, Clark County, MO, Knox County, MO, Lewis County, MO, Marion County, MO, Scotland County, MO, Shelby County, MO

The radar

The Lincoln radar (KILX), 127 km from the middle of the area, began a volume at 12:55 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
40%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 30, 8:14 AM CDTSevere Thunderstorm WarningDVNHenry, Mercer, Rock Island61 min
May 30, 9:30 AM CDTSevere Thunderstorm WarningDVNBureau, Putnam50 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, 0.9 hours before the alert went out and 140 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 12:00Z on 2008-05-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 349 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, Davenport, at 12:00Z on 2008-05-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 square meters per square second.19395878Sfc1 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
349 J/kg
Mixed-layer CIN
-110 J/kg
Mixed-layer LCL
605 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
272 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 30, 1:19 AM CDTTornado WatchSPCHancock, Henderson, McDonough, Mercer, Rock Island, Warren8 hr
May 30, 2:17 AM CDTMesoscale DiscussionSPCHancock, Henderson, McDonough, Mercer, Rock Island, Warren88 min
May 30, 6:00 AM CDTMesoscale DiscussionSPCCarroll, Hancock, Henderson, Henry, Knox, Mercer and 3 more2 hr
May 30, 10:13 AM CDTMesoscale DiscussionSPCCook, DuPage, Grundy, Kendall, LaSalle, Will62 min
May 30, 1:14 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Champaign, Christian and 24 more2 hr
May 30, 1:56 PM CDTTornado WatchSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 37 more8 hr
May 30, 4:29 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 19 more61 min
May 30, 5:18 PM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 37 more87 min
May 29, 7:37 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Boone, Calhoun and 25 more53 min
May 29, 8:13 PM CDTTornado WatchSPCAdair, Adams, Appanoose, Audubon, Boone, Calhoun and 29 more8 hr
May 29, 10:21 PM CDTMesoscale DiscussionSPCPlymouth, Sioux, Woodbury24 min
May 29, 11:34 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 38 more56 min
May 30, 1:37 AM CDTMesoscale DiscussionSPCFremont, Harrison, Mills, Monona, Montgomery, Page and 2 more53 min
May 30, 4:58 PM CDTSevere Thunderstorm WatchSPCAllamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more3 hr
May 30, 2:23 PM CDTMesoscale DiscussionSPCBates, Caldwell, Carroll, Cass, Chariton, Clay and 15 more97 min
May 30, 2:42 PM CDTTornado WatchSPCAdair, Barton, Bates, Benton, Caldwell, Camden and 36 more7 hr

Nearby

Tornado Watches in Illinois, 2008Tornado Watches in Iowa, 2008Tornado Watches in Missouri, 2008Every tornado watch in 2008

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.