Alert archive / Illinois / Mesoscale Discussions in 2012

Mesoscale Discussion 1889

September 5, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Sep 5, 2012, 9:04 AM CDT for 4 states. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Sep 5, 2012, 9:04 AM CDT (14:04 UTC)
Expired
Sep 5, 2012, 10:30 AM CDT
In force
86 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 85 counties

Alexander County, IL, Bond County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Crawford County, IL, Cumberland 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, Pulaski County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Clay County, IN, Crawford County, IN, Daviess County, IN, Dubois County, IN, Gibson County, IN, Greene County, IN, Harrison County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Orange County, IN, Owen County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Sullivan County, IN, Vanderburgh County, IN, Vigo County, IN, Warrick County, IN, Ballard County, KY, Breckinridge County, KY, Butler County, KY, Caldwell County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Daviess County, KY, Graves County, KY, Grayson County, KY, Hancock County, KY, Henderson County, KY, Hickman County, KY, Hopkins County, KY, Livingston County, KY, Logan County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McLean County, KY, Meade County, KY, Muhlenberg County, KY, Ohio County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Webster County, KY, Cape Girardeau County, MO, Mississippi County, MO, Perry County, MO, Scott County, MO

The radar

The Evansville,IN radar (KVWX), 49 km from the middle of the area, began a volume at 14:05 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, 2.1 hours before the alert went out and 229 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-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2012-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1271 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2012-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 107 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
1271 J/kg
Mixed-layer CIN
-188 J/kg
Mixed-layer LCL
1037 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
107 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 4, 8:30 PM CDTMesoscale DiscussionSPCJo Daviess60 min
Sep 4, 8:51 PM CDTSevere Thunderstorm WatchSPCBoone, Carroll, Cook, DeKalb, DuPage, Grundy and 13 more5 hr
Sep 5, 1:14 AM CDTMesoscale DiscussionSPCCarroll, Henry, Jo Daviess, Rock Island, Stephenson, Whiteside and 1 more91 min
Sep 5, 3:43 AM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, Grundy, Henderson and 21 more92 min
Sep 5, 9:37 AM CDTSevere Thunderstorm WatchSPCBond, Clark, Clay, Clinton, Coles, Crawford and 24 more6 hr
Sep 5, 1:10 PM CDTMesoscale DiscussionSPCGallatin, Hardin, Johnson, Massac, Pope65 min
Sep 5, 1:43 PM CDTSevere Thunderstorm WatchSPCHardin5 hr
Sep 5, 2:13 PM CDTMesoscale DiscussionSPCAlexander, Massac, Pulaski2 hr
Sep 5, 2:29 PM CDTSevere Thunderstorm WatchSPCAlexander, Johnson, Massac, Pope, Pulaski, Union8 hr
Sep 5, 4:02 PM CDTMesoscale DiscussionSPCBoone, Carroll, Cook, DeKalb, DuPage, Jo Daviess and 7 more88 min
Sep 5, 5:31 PM CDTMesoscale DiscussionSPCAdair, Allen, Bath, Bourbon, Boyle, Casey and 28 more89 min

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.