Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 404

April 10, 201124 counties in Illinois; 15 counties in Indiana; 18 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2011, 11:03 PM CDT for 24 counties in Illinois; 15 counties in Indiana; 18 counties in Michigan. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 10, 2011, 11:03 PM CDT (04:03 UTC)
Expired: Apr 11, 2011, 12:30 AM CDT
In force: 87 min
Issued by: the Storm Prediction Center

All 57 counties

Bond County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, Cook County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Fayette County, IL, Ford County, IL, Iroquois County, IL, Kankakee County, IL, Livingston County, IL, Macon County, IL, Macoupin County, IL, McLean County, IL, Montgomery County, IL, Moultrie County, IL, Piatt County, IL, Shelby County, IL, Vermilion County, IL, Will County, IL, Benton County, IN, Elkhart County, IN, Fountain County, IN, Fulton County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Warren County, IN, White County, IN, Allegan County, MI, Barry County, MI, Berrien County, MI, Calhoun County, MI, Cass County, MI, Clinton County, MI, Eaton County, MI, Gratiot County, MI, Ionia County, MI, Isabella County, MI, Kalamazoo County, MI, Kent County, MI, Mecosta County, MI, Montcalm County, MI, Newaygo County, MI, Ottawa County, MI, Saint Joseph County, MI, Van Buren County, MI

The radar

The Chicago radar (KLOT), 86 km from the middle of the area, began a volume at 04:07 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 00:00Z, 4.1 hours before the alert went out and 219 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: 1523 J/kg
Mixed-layer CIN: -79 J/kg
Mixed-layer LCL: 1493 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 207 m²/s²
0-3 km storm-relative helicity: 237 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 6.7

Open this sounding in Storm Lab

The text

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

705 
ACUS11 KWNS 110404
SWOMCD
SPC MCD 110403
MIZ000-INZ000-ILZ000-MOZ000-110530-

MESOSCALE DISCUSSION 0404
NWS STORM PREDICTION CENTER NORMAN OK
1103 PM CDT SUN APR 10 2011

AREAS AFFECTED...PARTS OF SRN LWR MI...NWRN IND...CNTRL AND ERN IL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 110403Z - 110530Z

SEVERE POTENTIAL MAY REMAIN SOMEWHAT SPARSE IN COVERAGE...BUT TRENDS
ARE BEING MONITORED FOR THE POSSIBILITY OF AN INCREASING SEVERE
THREAT THAT COULD REQUIRE A WW.

STRONGER SURFACE PRESSURE FALLS ASSOCIATED WITH THE DEEPENING
CYCLONE ARE SHIFTING INTO ONTARIO...WITH STRONGEST MID/UPPER FORCING
FOR UPWARD VERTICAL MOTION.  HOWEVER...LARGE-SCALE ASCENT AHEAD OF
AN UPPER TROUGH AXIS TRAILING SOUTHWESTWARD INTO THE MIDDLE
MISSISSIPPI VALLEY HAS STRENGTHENED SUFFICIENTLY TO SUPPORT
INCREASING CONVECTIVE DEVELOPMENT IN A NARROW BAND AHEAD OF AN
EASTWARD ADVANCING COLD FRONT.  IT IS NOT CLEAR THAT THIS ACTIVITY
IS ROOTED IN THE BOUNDARY LAYER...WHICH IS SLOWLY STABILIZING... BUT
WEAK TO MODERATE CAPE AND PRECIPITABLE WATER UP TO AROUND 1.5 INCHES
MAY BE SUFFICIENT TO MAINTAIN VIGOROUS UPDRAFTS OVERNIGHT. GIVEN THE
STRENGTH OF THE DEEP LAYER MEAN SOUTHWESTERLY FLOW IN WHICH THE
STORMS ARE EMBEDDED /IN EXCESS OF 50 KT/...AND SIZABLE SUB-CLOUD
TEMPERATURE/DEW POINT SPREADS EVIDENT IN 00Z RAOBS AND FORECAST
SOUNDINGS...STORMS PROBABLY WILL BE ACCOMPANIED BY THE RISK FOR AT
LEAST LOCALLY DAMAGING WIND GUSTS.

..KERR.. 04/11/2011

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

ATTN...WFO...DTX...IWX...GRR...IND...LOT...ILX...LSX...

LAT...LON   41728805 42988705 44028546 43538410 42218502 38888850
            38889031 41728805

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 12:48 AM CDT	Mesoscale Discussion	SPC	Bond, Clark, Clay, Clinton, Coles, Crawford and 10 more	87 min
Apr 10, 8:17 PM CDT	Tornado Watch	SPC	Alger, Baraga, Chippewa, Delta, Dickinson, Luce and 4 more	4 hr
Apr 10, 8:55 PM CDT	Mesoscale Discussion	SPC	Alger, Alpena, Antrim, Benzie, Charlevoix, Cheboygan and 26 more	95 min

Nearby

Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Michigan, 2011 Mesoscale Discussions in Indiana, 2011 Every 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.