Alert archive / Illinois / Mesoscale Discussions in 2012
Mesoscale Discussion 552
The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2012, 4:22 PM CDT for 35 counties in Arkansas; 37 counties in Illinois; 29 counties in Missouri. It was in force for 83 min.
The area
The outline as issued.
The facts
- Issued
- Apr 15, 2012, 4:22 PM CDT (21:22 UTC)
- Expired
- Apr 15, 2012, 5:45 PM CDT
- In force
- 83 min
- Issued by
- the Storm Prediction Center
All 101 counties
Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Clay County, AR, Cleburne County, AR, Cleveland County, AR, Craighead County, AR, Cross County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Faulkner County, AR, Fulton County, AR, Grant County, AR, Greene County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Jefferson County, AR, Lawrence County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Ouachita County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Sharp County, AR, St. Francis County, AR, Union County, AR, White County, AR, Woodruff County, AR, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, DeWitt County, IL, Fayette County, IL, Fulton County, IL, Greene County, IL, Jackson County, IL, Jersey County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Perry County, IL, Piatt 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, Woodford 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, Montgomery County, MO, Oregon County, MO, Perry County, MO, Pike County, MO, Reynolds County, MO, Ripley County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shannon County, MO, Stoddard County, MO, Warren County, MO, Washington County, MO, Wayne County, MO
The radar
The St Louis radar (KLSX), 178 km from the middle of the area, began a volume at 21:22 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
Springfield, MO (KSGF), launched 12:00Z, 9.4 hours before the alert went out and 246 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
- 31 J/kg
- Mixed-layer CIN
- -142 J/kg
- Mixed-layer LCL
- 855 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 319 m²/s²
- 0-3 km storm-relative helicity
- 381 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
582
ACUS11 KWNS 152123
SWOMCD
SPC MCD 152122
ILZ000-MOZ000-ARZ000-MSZ000-152245-
MESOSCALE DISCUSSION 0552
NWS STORM PREDICTION CENTER NORMAN OK
0422 PM CDT SUN APR 15 2012
AREAS AFFECTED...E CNTRL MO INTO CNTRL IL
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 152122Z - 152245Z
ADDITIONAL WWS ARE LIKELY TO BE ISSUED SHORTLY EAST OF ONGOING
CONVECTIVE LINE ACROSS THE MISSISSIPPI VALLEY.
SQUALL LINE EXTENDING FROM THE MISSOURI OZARKS INTO THE ARKLATEX IS
STILL FLUCTUATING IN STRENGTH...AND INSTABILITY AHEAD OF IT DOES NOT
APPEAR PARTICULARLY STRONG. HOWEVER...IT DOES APPEAR TO BE
SUPPORTED BY SUBSTANTIVE MID/UPPER FORCING FOR UPWARD VERTICAL
MOTION...DOWNSTREAM OF THE LARGE-SCALE TROUGH SLOWLY SHIFTING INTO
THE PLAINS. EMBEDDED WITHIN 50-60+ KT SOUTHWESTERLY DEEP LAYER MEAN
FLOW...POTENTIAL FOR DAMAGING WIND GUSTS...PERHAPS LOCALLY ENHANCED
BY EMBEDDED MESOCYCLONES/ISOLATED TORNADOES... STILL APPEARS LIKELY
TO INCREASE LATE THIS AFTERNOON AND EVENING. A STRENGTHENING
SOUTHERLY 850 MB JET CORE MAY ACCOMPANY THE LINE...AND CONTRIBUTE TO
NORTHEASTWARD ACCELERATION OF THE LINE ACROSS PARTS OF EAST CENTRAL
AND SOUTHEAST MISSOURI INTO CENTRAL AND SOUTHERN ILLINOIS BETWEEN
NOW AND 00-02Z.
..KERR.. 04/15/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PAH...LOT...ILX...MEG...JAN...LSX...DVN...LZK...
SGF...SHV...
LAT...LON 38839170 40339090 40878984 40768866 39738836 38578878
36648991 34219082 33329174 33059237 33369334 34389279
35779210 37109194 38219169 38839170SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 15, 6:35 AM CDT | Mesoscale Discussion | SPC | Benton, Crawford, Madison, Sebastian, Washington | 85 min |
| Apr 15, 6:38 AM CDT | Severe Thunderstorm Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 4 hr |
| Apr 15, 9:25 AM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 22 more | 95 min |
| Apr 15, 10:51 AM CDT | Tornado Watch | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 18 more | 7 hr |
| Apr 15, 1:38 PM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 18 more | 97 min |
| Apr 15, 3:44 PM CDT | Mesoscale Discussion | SPC | Calhoun, Clark, Columbia, Hempstead, Lafayette, Miller and 3 more | 91 min |
| Apr 15, 4:25 PM CDT | Tornado Watch | SPC | Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 49 more | 6 hr |
| Apr 14, 8:41 PM CDT | Severe Thunderstorm Watch | SPC | Bureau, Carroll, Henderson, Henry, Mercer, Putnam and 3 more | 4 hr |
| Apr 14, 9:54 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Henry and 12 more | 96 min |
| Apr 15, 4:42 PM CDT | Tornado Watch | SPC | Adams, Bond, Brown, Calhoun, Cass, Clinton and 15 more | 6 hr |
| Apr 15, 6:12 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 25 more | 63 min |
| Apr 14, 11:28 PM CDT | Mesoscale Discussion | SPC | Putnam | 92 min |
| Apr 14, 11:48 PM CDT | Mesoscale Discussion | SPC | Clay, Platte | 87 min |
| Apr 15, 1:37 AM CDT | Tornado Watch | SPC | Andrew, Atchison, Buchanan, DeKalb, Gentry, Holt and 2 more | 5 hr |
| Apr 15, 4:32 AM CDT | Mesoscale Discussion | SPC | Bates, Buchanan, Caldwell, Cass, Clay, Clinton and 6 more | 88 min |
Nearby
Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Missouri, 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.