Alert archive / Missouri / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 791

August 27, 200413 counties in Illinois; 39 counties in Missouri

The Storm Prediction Center issued this severe thunderstorm watch at Aug 27, 2004, 9:40 AM CDT for 13 counties in Illinois; 39 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Aug 27, 2004, 9:40 AM CDT (14:40 UTC)
Expired
Aug 27, 2004, 3:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 52 counties

Brown County, IL, Calhoun County, IL, Cass County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Mason County, IL, Menard County, IL, Morgan County, IL, Pike County, IL, Sangamon County, IL, Scott County, IL, Audrain County, MO, Barton County, MO, Bates County, MO, Benton County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Cass County, MO, Cedar County, MO, City of Saint Louis, MO, Cole County, MO, Cooper County, MO, Dade County, MO, Dallas County, MO, Franklin County, MO, Gasconade County, MO, Henry County, MO, Hickory County, MO, Howard County, MO, Jasper County, MO, Johnson County, MO, Lincoln County, MO, Maries County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Pettis County, MO, Pike County, MO, Polk County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Saline County, MO, St. Clair County, MO, Vernon County, MO, Warren County, MO

The radar

The Pleasant Hill radar (KEAX), 154 km from the middle of the area, began a volume at 14:42 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.

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 27, 2:09 PM CDTSevere Thunderstorm WarningLSXCallaway, Montgomery51 min
Aug 27, 2:16 PM CDTTornado WarningLSXCallaway, Montgomery44 min
Aug 27, 2:46 PM CDTTornado WarningLSXWarren44 min
Aug 27, 2:50 PM CDTSevere Thunderstorm WarningLSXOsage25 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

Springfield, MO (KSGF), launched 12:00Z, 2.7 hours before the alert went out and 237 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, Springfield, MO at 12:00Z on 2004-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1722 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, Springfield, MO at 12:00Z on 2004-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 189 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
1722 J/kg
Mixed-layer CIN
-128 J/kg
Mixed-layer LCL
915 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
189 m²/s²
0-3 km storm-relative helicity
211 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
Aug 26, 9:13 PM CDTMesoscale DiscussionSPCCarroll, Jo Daviess, Rock Island, Stephenson62 min
Aug 26, 9:45 PM CDTSevere Thunderstorm WatchSPCBoone, Carroll, Henderson, Henry, Jo Daviess, Mercer and 5 more6 hr
Aug 26, 11:53 PM CDTMesoscale DiscussionSPCBureau, Cook, DeKalb, DuPage, Grundy, Kane and 8 more97 min
Aug 27, 1:25 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Cook, DeKalb, DeWitt, DuPage and 25 more6 hr
Aug 27, 1:49 AM CDTMesoscale DiscussionSPCHenderson, Henry, Mercer, Ogle, Rock Island, Whiteside and 1 more56 min
Aug 27, 4:36 AM CDTMesoscale DiscussionSPCCook, DeWitt, Ford, Fulton, Grundy, Hancock and 11 more84 min
Aug 27, 6:33 AM CDTMesoscale DiscussionSPCChampaign, DeWitt, Ford, Iroquois, McLean, Mason and 4 more27 min
Aug 27, 9:24 AM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Macoupin, Madison, Morgan and 2 more96 min
Aug 27, 1:07 PM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Greene, Jersey and 6 more113 min
Aug 27, 2:45 PM CDTSevere Thunderstorm WatchSPCCalhoun, Cass, Greene, Jersey, Morgan, Pike and 1 more6 hr
Aug 27, 3:49 PM CDTMesoscale DiscussionSPCCalhoun, Cass, Greene, Jersey, Morgan, Pike and 1 more86 min
Aug 27, 4:10 PM CDTMesoscale DiscussionSPCAdams, Brown, Bureau, Fulton, Hancock, Henderson and 14 more2 hr
Aug 26, 7:45 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Daviess, Gentry, Harrison, Holt and 3 more90 min
Aug 27, 2:45 PM CDTSevere Thunderstorm WatchSPCAdair, Buchanan, Caldwell, Carroll, Chariton, Clay and 17 more6 hr

Nearby

Severe Thunderstorm Watches in Missouri, 2004Severe Thunderstorm Watches in Illinois, 2004Every severe thunderstorm watch in 2004

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.