Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 893

May 23, 201140 counties in Illinois; 12 counties in Indiana; City of Saint Louis, Missouri

The Storm Prediction Center issued this mesoscale discussion at May 23, 2011, 12:37 PM CDT for 40 counties in Illinois; 12 counties in Indiana; City of Saint Louis, Missouri. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: May 23, 2011, 12:37 PM CDT (17:37 UTC)
Expired: May 23, 2011, 2:00 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center

All 53 counties

Bond County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Lawrence County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Moultrie County, IL, Perry County, IL, Piatt County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Sangamon County, IL, Shelby County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Clay County, IN, Daviess County, IN, Gibson County, IN, Greene County, IN, Knox County, IN, Pike County, IN, Posey County, IN, Sullivan County, IN, Vanderburgh County, IN, Vermillion County, IN, Vigo County, IN, Warrick County, IN, City of Saint Louis, MO

The radar

The Evansville,IN radar (KVWX), 102 km from the middle of the area, began a volume at 17:35 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.

Severe Thunderstorm Watch 341May 23, 12:55 PM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 5.6 hours before the alert went out and 143 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: 504 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1171 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 139 m²/s²
0-3 km storm-relative helicity: 167 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

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

788 
ACUS11 KWNS 231738
SWOMCD
SPC MCD 231737
INZ000-KYZ000-ILZ000-MOZ000-231900-

MESOSCALE DISCUSSION 0893
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT MON MAY 23 2011

AREAS AFFECTED...E-CNTRL MO...CNTRL/SRN IL/IND

CONCERNING...SEVERE THUNDERSTORM WATCH 340...

VALID 231737Z - 231900Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 340
CONTINUES.

FAST-MOVING BOWING LINE WILL LIKELY PRODUCE A SWATH OF DAMAGING
WINDS EAST OF THE SAINT LOUIS METRO AREA IN PARTS OF SRN IL THROUGH
19Z. THIS SEGMENT MAY REACH THE ERN PORTIONS OF WW 340 BY 19Z...WITH
THE PROBABILITY OF A DOWNSTREAM WW ISSUANCE AT 80 PERCENT.

AS OF 1730Z...BOWING LINE SEGMENT WITH A MEAN FORWARD PROPAGATION
SPEED OF 50-55 KT HAD REACH THE SAINT LOUIS METRO AREA WITH A 54 KT
GUST MEASURED AT KSTL. ENVIRONMENT WILL REMAIN SUPPORTIVE OF
MAINTAINING THIS FEATURE EWD ACROSS SRN IL. STRONG NEARLY
UNIDIRECTIONAL LOW/MID-LEVEL WLYS /AS SAMPLED BY WINCHESTER IL
PROFILER/ WILL REMAIN IN PLACE...IN CONJUNCTION WITH HEATING AND
INCREASINGLY RICH MOISTURE RETURN NOTED IN RECENT SURFACE
OBSERVATIONS.

ADDITIONAL TSTM DEVELOPMENT MAY ALSO OCCUR ALONG THE LEADING EDGE OF
THE RICHER MOISTURE ACROSS CNTRL IL/IND WHERE CU FIELD HAS INCREASED
PER VISIBLE SATELLITE IMAGERY. THE COMBINATION OF THE BOWING LINE
AND/OR ADDITIONAL TSTM INITIATION WILL NECESSITATE A DOWNSTREAM
SEVERE TSTM WATCH ISSUANCE BY 19Z.

..GRAMS.. 05/23/2011

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

ATTN...WFO...LMK...IND...PAH...ILX...LSX...

LAT...LON   37959032 38969029 39569035 39998958 40028817 39868741
            39138686 38838688 38538702 37898738 37668871 37959032

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 22, 7:52 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Clinton, Greene, Jersey, Macoupin and 6 more	53 min
May 22, 8:26 PM CDT	Tornado Watch	SPC	Bond, Calhoun, Cass, Champaign, Christian, Clay and 35 more	8 hr
May 22, 9:35 PM CDT	Mesoscale Discussion	SPC	DeKalb, DuPage, Grundy, Iroquois, Kane, Kankakee and 6 more	55 min
May 22, 10:24 PM CDT	Mesoscale Discussion	SPC	Clark, Clay, Coles, Crawford, Cumberland, Edgar and 9 more	66 min
May 23, 7:25 AM CDT	Mesoscale Discussion	SPC	Edgar, Vermilion	65 min
May 23, 10:55 AM CDT	Severe Thunderstorm Watch	SPC	Alexander, Bond, Calhoun, Clinton, Edwards, Fayette and 27 more	7 hr
May 23, 12:54 PM CDT	Severe Thunderstorm Watch	SPC	Champaign, Christian, Clark, Clay, Coles, Crawford and 13 more	5 hr
May 23, 2:52 PM CDT	Mesoscale Discussion	SPC	Clark, Clay, Coles, Crawford, Cumberland, Edgar and 8 more	53 min
May 23, 3:58 PM CDT	Mesoscale Discussion	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 14 more	92 min
May 23, 4:24 PM CDT	Mesoscale Discussion	SPC	Massac	96 min
May 22, 7:20 PM CDT	Mesoscale Discussion	SPC	Adams, Allen, Benton, Blackford, Boone, Carroll and 33 more	115 min
May 22, 9:59 PM CDT	Mesoscale Discussion	SPC	Allen, Carroll, Cass, DeKalb, Elkhart, Fulton and 14 more	61 min
May 23, 3:20 AM CDT	Mesoscale Discussion	SPC	Clark, Floyd, Harrison, Jefferson, Ohio, Scott and 1 more	85 min
May 23, 11:35 AM CDT	Mesoscale Discussion	SPC	Adams, Allen, Blackford, Cass, DeKalb, Elkhart and 13 more	85 min
May 23, 1:15 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Allen, Blackford, Cass, DeKalb, Elkhart and 15 more	8 hr
May 23, 3:28 PM CDT	Severe Thunderstorm Watch	SPC	Clark, Crawford, Dearborn, Dubois, Fayette, Floyd and 12 more	6 hr
May 23, 5:20 PM CDT	Mesoscale Discussion	SPC	Clark, Crawford, Dearborn, Decatur, Fayette, Floyd and 15 more	55 min
May 23, 5:40 PM CDT	Mesoscale Discussion	SPC	Adams, Allen, Blackford, DeKalb, Grant, Howard and 8 more	65 min
May 22, 8:47 PM CDT	Tornado Watch	SPC	Dunklin, Pemiscot	7 hr
May 22, 11:46 PM CDT	Mesoscale Discussion	SPC	Dunklin, Pemiscot	89 min
May 23, 5:07 AM CDT	Mesoscale Discussion	SPC	Barry, Barton, Carter, Cedar, Christian, Dade and 24 more	113 min
May 23, 5:41 AM CDT	Mesoscale Discussion	SPC	Barton, Bates, Cedar, Dade, Hickory, Jasper and 5 more	94 min
May 23, 6:08 AM CDT	Severe Thunderstorm Watch	SPC	Barry, Barton, Bates, Benton, Camden, Cass and 34 more	7 hr
May 23, 7:38 AM CDT	Mesoscale Discussion	SPC	Barry, Barton, Bates, Benton, Camden, Cedar and 17 more	97 min
May 23, 10:34 AM CDT	Mesoscale Discussion	SPC	Barry, Barton, Bollinger, Butler, Camden, Carter and 37 more	86 min
May 23, 12:12 PM CDT	Mesoscale Discussion	SPC	Barry, Camden, Carter, Christian, Dade, Dallas and 24 more	93 min
May 23, 1:16 PM CDT	Mesoscale Discussion	SPC	Butler, Dunklin, New Madrid, Pemiscot, Ripley	89 min
May 23, 1:34 PM CDT	Severe Thunderstorm Watch	SPC	Dunklin, Pemiscot	6 hr

Nearby

Mesoscale Discussions in Illinois, 2011 Mesoscale Discussions in Indiana, 2011 Mesoscale Discussions in Missouri, 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.