Alert archive / Illinois / Mesoscale Discussions in 2012
Mesoscale Discussion 1574
The Storm Prediction Center issued this mesoscale discussion at Jul 24, 2012, 3:25 PM CDT for 26 counties in Illinois; 12 counties in Indiana; 23 counties in Kentucky. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Jul 24, 2012, 3:25 PM CDT (20:25 UTC)
- Expired
- Jul 24, 2012, 5:00 PM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 61 counties
Clay County, IL, Clinton County, IL, Crawford County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Johnson County, IL, Lawrence County, IL, Marion County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Richland County, IL, Saline County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Crawford County, IN, Daviess County, IN, Dubois County, IN, Gibson County, IN, Knox County, IN, Orange County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Breckinridge County, KY, Butler County, KY, Caldwell County, KY, Christian County, KY, Crittenden County, KY, Daviess County, KY, Edmonson County, KY, Grayson County, KY, Hancock County, KY, Henderson County, KY, Hopkins County, KY, Livingston County, KY, Logan County, KY, Lyon County, KY, McLean County, KY, Meade County, KY, Muhlenberg County, KY, Ohio County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Warren County, KY, Webster County, KY
The radar
The Evansville,IN radar (KVWX), 20 km from the middle of the area, began a volume at 20:26 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, 8.4 hours before the alert went out and 241 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
- 841 J/kg
- Mixed-layer CIN
- -263 J/kg
- Mixed-layer LCL
- 2251 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 88 m²/s²
- 0-3 km storm-relative helicity
- 77 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
623
ACUS11 KWNS 242025
SWOMCD
SPC MCD 242025
KYZ000-INZ000-ILZ000-242200-
MESOSCALE DISCUSSION 1574
NWS STORM PREDICTION CENTER NORMAN OK
0325 PM CDT TUE JUL 24 2012
AREAS AFFECTED...SWRN IND...SRN IL...WRN KY
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 242025Z - 242200Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...AN ISOLATED THREAT FOR SEVERE THUNDERSTORMS MAY EXIST
THROUGH LATE AFTERNOON. WW ISSUANCE IS UNLIKELY OWING TO THE
ANTICIPATED SPORADIC NATURE OF THE SVR THREAT.
DISCUSSION...THE AIR MASS NEAR AND SOUTH OF A STALLING OUTFLOW
BOUNDARY EXTENDING FROM THE LOUISVILLE AREA TO 30 S DECATUR IL
CONTINUES TO DESTABILIZE AS TEMPERATURES HAVE WARMED TO THE UPPER
90S TO 104 DEGREES AMIDST SFC DEWPOINTS IN THE MIDDLE 60S TO THE
LOWER 70S. WITH 2500-3500 J/KG OF MLCAPE...A FEW STRONG TO SVR
STORMS WILL BE POSSIBLE AS CONVECTION DEVELOPS INVOF THE OUTFLOW
BOUNDARY AND ALONG SFC CONFLUENCE AXES LYING SOUTH OF THE BOUNDARY.
DCAPE VALUES IN EXCESS OF 1000 J/KG INDICATE THAT INTENSE DOWNDRAFTS
WILL BE POSSIBLE WITH COLLAPSING STORMS...ESPECIALLY GIVEN SFC
DEWPOINT DEPRESSIONS IN EXCESS OF 35F IN MANY AREAS.
ALSO...MARGINALLY SVR HAIL CANNOT BE RULED OUT. HOWEVER...WITH THE
REGION DISPLACED TO THE SW OF THE PRIMARY BELT OF STRONG
NWLYS...DEEP SHEAR SHOULD BE LIMITED...FOSTERING MORE OF A PULSE
CONVECTIVE MODE. GIVEN THE GENERALLY DISORGANIZED NATURE OF THE
CONVECTION...ANY INSTANCES OF SVR STORMS SHOULD BE SPORADIC.
..COHEN/HART.. 07/24/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LMK...IND...PAH...ILX...LSX...
LAT...LON 38978764 38508632 37738601 37068626 36778676 36768801
37478922 38238966 39128934 39348862 38978764SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 11:13 PM CDT | Mesoscale Discussion | SPC | Stephenson | 92 min |
| Jul 24, 3:32 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Grundy and 10 more | 58 min |
| Jul 24, 4:47 AM CDT | Severe Thunderstorm Watch | SPC | Boone, Cook, DeKalb, DuPage, Kane, Kankakee and 7 more | 4 hr |
| Jul 24, 6:35 AM CDT | Mesoscale Discussion | SPC | Cook, DeKalb, DuPage, Grundy, Kane, Kankakee and 4 more | 55 min |
| Jul 24, 7:00 AM CDT | Severe Thunderstorm Watch | SPC | Adams, Allen, Blackford, Boone, Carroll, Cass and 27 more | 3 hr |
| Jul 24, 9:08 AM CDT | Mesoscale Discussion | SPC | Adams, Blackford, Delaware, Fayette, Grant, Hamilton and 11 more | 97 min |
| Jul 24, 9:35 AM CDT | Severe Thunderstorm Watch | SPC | Dearborn, Fayette, Franklin, Ripley, Union, Wayne | 3 hr |
| Jul 24, 10:43 AM CDT | Mesoscale Discussion | SPC | Bath, Bourbon, Boyd, Breathitt, Carter, Clark and 26 more | 62 min |
| Jul 24, 10:59 AM CDT | Mesoscale Discussion | SPC | Boone, Bracken, Campbell, Greenup, Kenton, Lewis and 3 more | 61 min |
| Jul 24, 11:33 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Anderson, Bath, Bell, Bourbon, Boyd and 61 more | 6 hr |
| Jul 24, 12:52 PM CDT | Mesoscale Discussion | SPC | Anderson, Bath, Bourbon, Boyd, Boyle, Breathitt and 47 more | 53 min |
| Jul 24, 2:25 PM CDT | Mesoscale Discussion | SPC | Adair, Anderson, Bell, Bourbon, Boyle, Breathitt and 44 more | 95 min |
| Jul 24, 5:20 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Allen, Barren, Bell, Breckinridge, Butler and 26 more | 4 hr |
Nearby
Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Indiana, 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.