Alert archive / Illinois / Mesoscale Discussions in 2012
Mesoscale Discussion 734
The Storm Prediction Center issued this mesoscale discussion at May 6, 2012, 3:56 PM CDT for 38 counties in Illinois; Lee County, Iowa; 31 counties in Missouri. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- May 6, 2012, 3:56 PM CDT (20:56 UTC)
- Expired
- May 6, 2012, 5:00 PM CDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
All 70 counties
Lee County, IA, Adams County, IL, Brown County, IL, Cass County, IL, Champaign County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Iroquois County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle 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, Morgan County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Will County, IL, Woodford County, IL, Adair County, MO, Audrain County, MO, Boone County, MO, Caldwell County, MO, Carroll County, MO, Chariton County, MO, Clark County, MO, Cooper County, MO, Daviess County, MO, Grundy County, MO, Henry County, MO, Howard County, MO, Johnson County, MO, Knox County, MO, Lafayette County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Pettis County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO
The radar
The St Louis radar (KLSX), 168 km from the middle of the area, began a volume at 21:00 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
Davenport, (KDVN), launched 12:00Z, 8.9 hours before the alert went out and 193 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.
- Mixed-layer CAPE
- 2361 J/kg
- Mixed-layer CIN
- -82 J/kg
- Mixed-layer LCL
- 571 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 181 m²/s²
- 0-3 km storm-relative helicity
- 188 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 9.6
The text
As transmitted, in the capitals the NWS used until 2016.
519 ACUS11 KWNS 062056 SWOMCD SPC MCD 062056 ILZ000-MOZ000-IAZ000-062200- MESOSCALE DISCUSSION 0734 NWS STORM PREDICTION CENTER NORMAN OK 0356 PM CDT SUN MAY 06 2012 AREAS AFFECTED...NRN IL TO NRN MO CONCERNING...SEVERE THUNDERSTORM WATCH 258... VALID 062056Z - 062200Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 258 CONTINUES. SUMMARY...AN EXPANDING CLUSTER OF SEVERE THUNDERSTORMS SHOULD SPREAD ACROSS NRN IL INTO NWRN IND OVER THE NEXT FEW HOURS. OTHER ISOLATED SEVERE THUNDERSTORMS WILL PERSIST SWWD INTO MO AS WELL. DISCUSSION...MULTIPLE THUNDERSTORM CLUSTERS HAVE EVOLVED ALONG OUTFLOW BOUNDARY THAT IS DRAPED ACROSS NRN IL...AT TIMES SEVERAL OF THESE STRUCTURES HAVE EXHIBITED SUPERCELL CHARACTERISTICS. EVEN SO STORM MERGERS ARE RESULTING IN AN EXPANDING CORRIDOR OF CONVECTION THAT COULD EVOLVE INTO AN MCS. THIS ACTIVITY SHOULD SPREAD/DEVELOP SLOWLY ESEWD INTO EXTREME NWRN IND OVER THE NEXT FEW HOURS. FARTHER SW...ISOLATED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG THE OUTFLOW ACROSS NRN MO. ..DARROW.. 05/06/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LOT...ILX...LSX...DVN...SGF...DMX...EAX... LAT...LON 40039414 41858759 40138758 38299413 40039414
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 6, 8:40 AM CDT | Mesoscale Discussion | SPC | Bureau, Fulton, Hancock, Henderson, Henry, Knox and 12 more | 65 min |
| May 6, 9:29 AM CDT | Severe Thunderstorm Watch | SPC | Bureau, Carroll, Fulton, Hancock, Henderson, Henry and 11 more | 4 hr |
| May 6, 1:22 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Cass, Fulton, Grundy, Hancock and 20 more | 53 min |
| May 6, 1:42 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Bureau, Cass, Champaign, Cook and 35 more | 7 hr |
| May 6, 5:07 PM CDT | Mesoscale Discussion | SPC | Clark, Edgar, Iroquois, Vermilion | 53 min |
| May 5, 10:03 PM CDT | Severe Thunderstorm Watch | SPC | Buena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 6 more | 7 hr |
| May 5, 11:31 PM CDT | Mesoscale Discussion | SPC | Lyon | 89 min |
| May 6, 2:12 AM CDT | Mesoscale Discussion | SPC | Buena Vista, Butler, Cerro Gordo, Cherokee, Clay, Dickinson and 17 more | 63 min |
| May 6, 4:55 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Cass, Fremont, Guthrie and 8 more | 2 hr |
| May 6, 7:17 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Appanoose, Clarke, Dallas, Davis and 16 more | 6 hr |
| May 6, 2:40 PM CDT | Mesoscale Discussion | SPC | Platte | 95 min |
| May 6, 3:49 PM CDT | Severe Thunderstorm Watch | SPC | Andrew, Bates, Buchanan, Cass, Clay, Clinton and 10 more | 7 hr |
Nearby
Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Missouri, 2012Mesoscale Discussions in Iowa, 2012Every mesoscale discussion in 2012
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.