Alert archive / Illinois / Mesoscale Discussions in 2013

Mesoscale Discussion 489

April 17, 201338 counties in Illinois; 21 counties in Iowa; 31 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2013, 8:49 AM CDT for 38 counties in Illinois; 21 counties in Iowa; 31 counties in Missouri. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Apr 17, 2013, 8:49 AM CDT (13:49 UTC)
Expired
Apr 17, 2013, 9:45 AM CDT
In force
56 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 90 counties

Appanoose County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Lucas County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Ringgold County, IA, Scott County, IA, Taylor County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Wayne County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Cass County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Woodford County, IL, Adair County, MO, Andrew County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Chariton County, MO, Clark County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Holt County, MO, Knox County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Marion County, MO, Mercer County, MO, Monroe County, MO, Nodaway County, MO, Putnam County, MO, Ralls County, MO, Randolph County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO, Worth County, MO

The radar

The Quad Cities radar (KDVN), 163 km from the middle of the area, began a volume at 13:51 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, 1.8 hours before the alert went out and 277 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 2013-04-17Temperature 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 12:00Z on 2013-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
540 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
299 m²/s²
Significant tornado parameter
0.0
Supercell composite
6.8

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 16, 8:02 PM CDTMesoscale DiscussionSPCEdwards, Gallatin, Hamilton, Hardin, Saline, Wabash and 1 more88 min
Apr 16, 8:44 PM CDTMesoscale DiscussionSPCBond, Calhoun, Champaign, Christian, Clark, Clay and 35 more2 hr
Apr 17, 9:14 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more10 hr
Apr 17, 9:30 AM CDTMesoscale DiscussionSPCHardin2 hr
Apr 17, 11:11 AM CDTTornado WatchSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more11 hr
Apr 17, 12:39 PM CDTSevere Thunderstorm WatchSPCHardin, Pope5 hr
Apr 17, 1:33 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more57 min
Apr 17, 3:04 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Clark, Coles, Cumberland and 26 more56 min
Apr 17, 3:33 PM CDTTornado WatchSPCCass, Champaign, Christian, Coles, DeWitt, Douglas and 24 more8 hr
Apr 17, 3:38 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more97 min
Apr 17, 3:53 PM CDTMesoscale DiscussionSPCHardin, Pope67 min
Apr 17, 6:02 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Pike88 min
Apr 17, 6:46 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Coles, DeWitt, Douglas and 18 more89 min
Apr 17, 4:19 PM CDTMesoscale DiscussionSPCDes Moines, Henry, Lee, Van Buren26 min
Apr 17, 9:50 AM CDTMesoscale DiscussionSPCBarton, Bates, Benton, Boone, Buchanan, Caldwell and 34 more55 min

Nearby

Mesoscale Discussions in Illinois, 2013Mesoscale Discussions in Missouri, 2013Mesoscale Discussions in Iowa, 2013Every mesoscale discussion in 2013

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.