Alert archive / Illinois / Mesoscale Discussions in 2005

Mesoscale Discussion 818

May 11, 200528 counties in Illinois; 17 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 11, 2005, 1:37 PM CDT for 28 counties in Illinois; 17 counties in Missouri. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
May 11, 2005, 1:37 PM CDT (18:37 UTC)
Expired
May 11, 2005, 3:30 PM CDT
In force
113 min
Issued by
the Storm Prediction Center
All 45 counties

Adams County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Coles County, IL, DeWitt County, IL, Douglas County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Jersey County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Pike County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Adair County, MO, Audrain County, MO, Chariton County, MO, Clark County, MO, Howard County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Scotland County, MO, Shelby County, MO

The radar

The St Louis radar (KLSX), 110 km from the middle of the area, began a volume at 18:38 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 6.6 hours before the alert went out and 222 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 2005-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1689 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 2005-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 148 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
1689 J/kg
Mixed-layer CIN
-80 J/kg
Mixed-layer LCL
1125 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
148 m²/s²
0-3 km storm-relative helicity
84 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 11, 3:11 AM CDTMesoscale DiscussionSPCBureau, Henry, Lee, Marshall, Mercer, Rock Island and 2 more2 hr
May 11, 8:41 AM CDTMesoscale DiscussionSPCAdams, Hancock2 hr
May 11, 1:55 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calhoun, Cass, Fulton, Greene and 11 more6 hr
May 11, 3:21 PM CDTMesoscale DiscussionSPCChampaign, Clark, Coles, Cumberland, DeWitt, Douglas and 4 more114 min
May 11, 6:28 PM CDTMesoscale DiscussionSPCChristian, Clark, Clay, Coles, Crawford, Cumberland and 13 more2 hr
May 11, 11:45 AM CDTTornado WatchSPCAdair, Andrew, Buchanan, Caldwell, Carroll, Chariton and 22 more7 hr
May 11, 3:41 PM CDTMesoscale DiscussionSPCAndrew, Audrain, Boone, Buchanan, Caldwell, Carroll and 19 more94 min
May 11, 4:50 PM CDTSevere Thunderstorm WatchSPCBates, Benton, Camden, Cass, Cole, Cooper and 8 more6 hr
May 11, 5:25 PM CDTMesoscale DiscussionSPCAndrew, Bates, Benton, Boone, Buchanan, Caldwell and 32 more2 hr
May 11, 6:45 PM CDTSevere Thunderstorm WatchSPCAtchison7 hr

Nearby

Mesoscale Discussions in Illinois, 2005Mesoscale Discussions in Missouri, 2005Every mesoscale discussion in 2005

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.