Alert archive / Illinois / Mesoscale Discussions in 2011
Mesoscale Discussion 1339
The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2011, 12:56 PM CDT for 46 counties in Illinois; 28 counties in Missouri. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2011, 12:56 PM CDT (17:56 UTC)
- Expired
- Jun 21, 2011, 2:00 PM CDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
All 74 counties
Alexander County, IL, Bond County, IL, Calhoun County, IL, Christian County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Greene County, IL, Hamilton County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Johnson County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Perry County, IL, Piatt County, IL, Pulaski County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Union County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Carter County, MO, City of Saint Louis, MO, Crawford County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Howell County, MO, Iron County, MO, Jefferson County, MO, Lincoln County, MO, Madison County, MO, Oregon County, MO, Perry County, MO, Reynolds County, MO, Ripley County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Shannon County, MO, Stoddard County, MO, Warren County, MO, Washington County, MO, Wayne County, MO
The radar
The St Louis radar (KLSX), 99 km from the middle of the area, began a volume at 17:58 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, 5.9 hours before the alert went out and 244 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
- 489 J/kg
- Mixed-layer CIN
- -145 J/kg
- Mixed-layer LCL
- 1353 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- -245 m²/s²
- 0-3 km storm-relative helicity
- -164 m²/s²
- Significant tornado parameter
- -0.1
- Supercell composite
- -5.5
The text
As transmitted, in the capitals the NWS used until 2016.
129
ACUS11 KWNS 211756
SWOMCD
SPC MCD 211756
ILZ000-MOZ000-211900-
MESOSCALE DISCUSSION 1339
NWS STORM PREDICTION CENTER NORMAN OK
1256 PM CDT TUE JUN 21 2011
AREAS AFFECTED...SERN MO...SRN IL
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 211756Z - 211900Z
STORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY FROM SERN
MO INTO SRN IL AND A WATCH COULD BE NEEDED.
SATELLITE IMAGERY SHOWS SIGNS OF AN MCV ACROSS SERN MO...WHICH WILL
CONTINUE NEWD INTO IL AHEAD OF A COLD FRONT. A VERY MOIST AND
UNSTABLE AIR MASS EXISTS AHEAD OF THE FRONT...AND AREA PROFILERS
INDICATE 40-50 KT MEAN DEEP LAYER FLOW AND EFFECTIVE SHEAR WHICH IS
FAVORABLE FOR STORM ORGANIZATION. HAIL IS LIKELY WITH THE STRONGER
CORES...AND SOME CELLS MAY EVENTUALLY MORPH INTO NNEWD MOVING LINE
SEGMENTS OR BOWS WITH A DAMAGING WIND THREAT.
TORNADO POTENTIAL IS A BIT MARGINAL WITH LOW LEVEL WINDS VEERING
WITH TIME...BUT STRONG INSTABILITY...FAVORABLY LOW LCL/LFC HEIGHTS
AND EFFECTIVE SRH ON THE ORDER OF 100 M2/S2 MAY BE SUFFICIENT FOR
ONE OR TWO BRIEF TORNADOES.
..JEWELL.. 06/21/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PAH...ILX...LSX...SGF...
LAT...LON 36569209 37399173 38759151 39469108 40228967 40228841
39938789 39278781 38408801 37688837 37488849 37058934
36768971 36579056 36569209SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 11:45 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DeWitt and 32 more | 3 hr |
| Jun 21, 1:22 PM CDT | Tornado Watch | SPC | Alexander, Bond, Calhoun, Cass, Champaign, Christian and 49 more | 9 hr |
| Jun 21, 3:31 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Calhoun, Cass, Champaign, Christian and 46 more | 89 min |
| Jun 21, 4:56 PM CDT | Mesoscale Discussion | SPC | Bond, Brown, Bureau, Cass, Champaign, Christian and 68 more | 94 min |
| Jun 21, 5:42 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Cook, DeKalb, DuPage, Ford and 23 more | 4 hr |
| Jun 20, 7:46 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Bates, Buchanan, Caldwell, Cass and 12 more | 59 min |
| Jun 20, 8:32 PM CDT | Tornado Watch | SPC | Adair, Andrew, Atchison, Barton, Bates, Benton and 40 more | 4 hr |
| Jun 20, 9:46 PM CDT | Severe Thunderstorm Watch | SPC | Barry, Barton, Benton, Cedar, Christian, Dade and 12 more | 9 hr |
| Jun 20, 10:22 PM CDT | Mesoscale Discussion | SPC | Adair, Caldwell, Carroll, Chariton, Clay, Clinton and 14 more | 83 min |
| Jun 21, 3:15 AM CDT | Mesoscale Discussion | SPC | Barry, Christian, Dade, Greene, Jasper, Lawrence and 5 more | 60 min |
Nearby
Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Missouri, 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.