Alert archive / Illinois / Mesoscale Discussions in 2012

Mesoscale Discussion 261

March 15, 201225 counties in Illinois; 25 counties in Indiana; 10 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Mar 15, 2012, 5:02 PM CDT for 25 counties in Illinois; 25 counties in Indiana; 10 counties in Ohio. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 15, 2012, 5:02 PM CDT (22:02 UTC)
Expired: Mar 15, 2012, 7:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 60 counties

Brown County, IL, Cass County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Iroquois County, IL, Kankakee County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Peoria County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Tazewell County, IL, Will County, IL, Woodford County, IL, Adams County, IN, Allen County, IN, Cass County, IN, DeKalb County, IN, Elkhart County, IN, Fulton County, IN, Huntington County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Newton County, IN, Noble County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Wabash County, IN, Wells County, IN, White County, IN, Whitley County, IN, Allen County, OH, Defiance County, OH, Fulton County, OH, Henry County, OH, Lucas County, OH, Paulding County, OH, Putnam County, OH, Van Wert County, OH, Williams County, OH, Wood County, OH

The radar

The Chicago radar (KLOT), 107 km from the middle of the area, began a volume at 22:03 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

Lincoln, IL (KILX), launched 12:00Z, 10.0 hours before the alert went out and 118 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1579 J/kg
Mixed-layer CIN: -52 J/kg
Mixed-layer LCL: 821 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 142 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

513 
ACUS11 KWNS 152203
SWOMCD
SPC MCD 152202
OHZ000-MIZ000-INZ000-ILZ000-160030-

MESOSCALE DISCUSSION 0261
NWS STORM PREDICTION CENTER NORMAN OK
0502 PM CDT THU MAR 15 2012

AREAS AFFECTED...NRN IN...CNTRL IL...NWRN OH

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 152202Z - 160030Z

A FEW SEVERE STORMS WILL BE POSSIBLE OVER THEN NEXT FEW
HOURS...MAINLY OVER NRN IND INTO NWRN OH. HAIL WILL BE POSSIBLE.

A BROKEN LINE OF THUNDERSTORMS CURRENTLY EXTENDS FROM N CNTRL IL
INTO NRN IND...EXTENDING NEWD INTO SERN LOWER MI. THESE STORMS WERE
ON THE TRAILING EDGE OF THE UPPER LEVEL VORT MAX SHIFTING EWD ACROSS
MI...AND ORIENTED W-E WITHIN A WEAK LOW PRESSURE TROUGH.

THE AIR MASS ACROSS THIS REGION IS VERY UNSTABLE WITH STEEP LAPSE
RATES THROUGH A DEEP LAYER. SHEAR IN THIS AREA IS RATHER WEAK...AND
FLOW IS LARGELY UNIDIRECTIONAL. THEREFORE...A LONG LIVED ORGANIZED
SEVERE THREAT IS NOT ANTICIPATED. HOWEVER..THERMODYNAMICS ARE VERY
FAVORABLE FOR PULSE OR MULTICELL SEVERE HAIL. THE THREAT IS EXPECTED
TO PEAK BETWEEN NOW AND 01Z BEFORE THE BOUNDARY LAYER COOLS.

..JEWELL.. 03/15/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...CLE...ILN...DTX...IWX...IND...LOT...ILX...LSX...
DVN...

LAT...LON   41738479 41698345 41288349 40728403 40718582 40648721
            40468822 39988921 39448979 39329014 39369077 39909096
            40609029 41278948 41558872 41668741 41738573 41738479

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 15, 1:08 PM CDT	Mesoscale Discussion	SPC	Alexander, Clay, Crawford, Edwards, Franklin, Gallatin and 15 more	2 hr
Mar 15, 2:06 PM CDT	Severe Thunderstorm Watch	SPC	Clark, Crawford, Dubois, Floyd, Harrison, Jefferson and 4 more	6 hr
Mar 15, 3:44 PM CDT	Mesoscale Discussion	SPC	Bartholomew, Clark, Dearborn, Decatur, Fayette, Floyd and 17 more	61 min
Mar 15, 4:28 PM CDT	Severe Thunderstorm Watch	SPC	Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more	3 hr
Mar 15, 2:19 AM CDT	Mesoscale Discussion	SPC	Allen, Ashland, Champaign, Clark, Coshocton, Crawford and 41 more	86 min
Mar 15, 2:52 PM CDT	Mesoscale Discussion	SPC	Allen, Defiance, Fulton, Hancock, Henry, Lucas and 8 more	83 min
Mar 15, 6:23 PM CDT	Mesoscale Discussion	SPC	Adams, Auglaize, Brown, Butler, Champaign, Clark and 12 more	97 min

Nearby

Mesoscale Discussions in Illinois, 2012 Mesoscale Discussions in Indiana, 2012 Mesoscale Discussions in Ohio, 2012 Every 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.