Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 468

April 19, 201140 counties in Illinois; 7 counties in Iowa; 25 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2011, 5:52 AM CDT for 40 counties in Illinois; 7 counties in Iowa; 25 counties in Missouri. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Apr 19, 2011, 5:52 AM CDT (10:52 UTC)
Expired
Apr 19, 2011, 7:15 AM CDT
In force
83 min
Issued by
the Storm Prediction Center
All 72 counties

Appanoose County, IA, Davis County, IA, Decatur County, IA, Lee County, IA, Ringgold County, IA, Van Buren County, IA, Wayne County, IA, Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clay County, IL, Clinton County, IL, Cumberland County, IL, DeWitt County, IL, Effingham County, IL, Fayette County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Perry County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Washington County, IL, Adair County, MO, Audrain County, MO, City of Saint Louis, MO, Clark County, MO, Franklin County, MO, Harrison County, MO, Jefferson County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Mercer County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Putnam County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO, Warren County, MO, Worth County, MO

The radar

The St Louis radar (KLSX), 81 km from the middle of the area, began a volume at 10:52 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 nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 10.9 hours before the alert went out and 216 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 00:00Z on 2011-04-19Temperature 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 00:00Z on 2011-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 194 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
1035 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
194 m²/s²
0-3 km storm-relative helicity
347 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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
Apr 18, 11:41 PM CDTMesoscale DiscussionSPCCalhoun, Jersey94 min
Apr 19, 2:53 AM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 21 more67 min
Apr 19, 3:11 AM CDTSevere Thunderstorm WatchSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 30 more7 hr
Apr 19, 8:29 AM CDTMesoscale DiscussionSPCChristian, Clark, Coles, Crawford, Cumberland, Douglas and 8 more61 min
Apr 19, 12:40 PM CDTMesoscale DiscussionSPCJersey, Madison, Monroe, Saint Clair95 min
Apr 19, 1:00 PM CDTTornado WatchSPCBond, Calhoun, Cass, Champaign, Christian, Clark and 36 more10 hr
Apr 19, 5:47 PM CDTMesoscale DiscussionSPCBond, Calhoun, Christian, Clark, Clay, Clinton and 25 more88 min
Apr 19, 6:24 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Jackson, Johnson, Pulaski, Saline and 2 more66 min
Apr 19, 6:46 PM CDTTornado WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more9 hr

Nearby

Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Missouri, 2011Mesoscale Discussions in Iowa, 2011Every mesoscale discussion in 2011

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.