Alert archive / Illinois / Mesoscale Discussions in 2007

Mesoscale Discussion 421

April 3, 200743 counties in Illinois; 43 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 3, 2007, 9:46 AM CDT for 43 counties in Illinois; 43 counties in Missouri. It was in force for 29 min.

The area

The outline as issued.

The facts

Issued
Apr 3, 2007, 9:46 AM CDT (14:46 UTC)
Expired
Apr 3, 2007, 10:15 AM CDT
In force
29 min
Issued by
the Storm Prediction Center
All 86 counties

Bond County, IL, Calhoun County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles 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, Greene County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Johnson 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, Union County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Audrain County, MO, Bates County, MO, Benton County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Cape Girardeau County, MO, Cass County, MO, City of Saint Louis, MO, Cole County, MO, Cooper County, MO, Crawford County, MO, Dallas County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Henry County, MO, Hickory County, MO, Howard County, MO, Iron County, MO, Jefferson County, MO, Johnson County, MO, Laclede County, MO, Lincoln County, MO, Madison County, MO, Maries County, MO, Miller County, MO, Moniteau County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Perry County, MO, Pettis County, MO, Phelps County, MO, Pulaski County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, St. Clair County, MO, Vernon County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 104 km from the middle of the area, began a volume at 14:49 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

Springfield, MO (KSGF), launched 12:00Z, 2.8 hours before the alert went out and 247 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, Springfield, MO at 12:00Z on 2007-04-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1571 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, Springfield, MO at 12:00Z on 2007-04-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 275 square meters per square second.193958Sfc1 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
1571 J/kg
Mixed-layer CIN
-171 J/kg
Mixed-layer LCL
930 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
275 m²/s²
0-3 km storm-relative helicity
294 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.6

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 031446
SWOMCD
SPC MCD 031446 
ILZ000-MOZ000-KSZ000-031515-

MESOSCALE DISCUSSION 0421
NWS STORM PREDICTION CENTER NORMAN OK
0946 AM CDT TUE APR 03 2007

AREAS AFFECTED...CENTRAL/SERN MO INTO CENTRAL/SRN IL

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON 

VALID 031446Z - 031515Z

NEW WW NEEDED SOON TO THE E AND SE OF WW/S 108 AND 109.

STRONG TO SEVERE STORMS CONTINUE TO DEVELOP ALONG/N OF A COUPLE OF
OUTFLOW BOUNDARIES MOVING ESEWD ACROSS ERN/CENTRAL IL AND CENTRAL
MO.  MOISTURE RETURN AND SURFACE HEATING IN ADVANCE OF THESE
BOUNDARIES WILL AID IN SUFFICIENT DESTABILIZATION FOR ADDITIONAL
TSTM DEVELOPMENT INTO THE AFTERNOON...WITH EFFECTIVE BULK SHEAR
VALUES SUPPORTIVE OF ORGANIZED SEVERE TSTMS.

..PETERS.. 04/03/2007

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

ATTN...WFO...PAH...ILX...LSX...SGF...EAX...

37899462 38639460 38979362 39229291 39319074 40058942
40048760 37508825 37299049 37539194 37679347

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 2, 9:22 PM CDTSevere Thunderstorm WatchSPCCarroll, Jo Daviess, Rock Island, Stephenson, Whiteside8 hr
Apr 2, 11:33 PM CDTMesoscale DiscussionSPCCarroll, Jo Daviess, Ogle, Stephenson, Winnebago57 min
Apr 3, 1:27 AM CDTMesoscale DiscussionSPCCarroll, Jo Daviess, Rock Island, Stephenson, Whiteside93 min
Apr 3, 4:05 AM CDTMesoscale DiscussionSPCAdams, Brown, Bureau, Cass, Fulton, Hancock and 19 more55 min
Apr 3, 4:19 AM CDTSevere Thunderstorm WatchSPCAdams, Brown, Bureau, Fulton, Hancock, Henderson and 16 more6 hr
Apr 3, 7:17 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Fulton, Greene and 15 more88 min
Apr 3, 9:08 AM CDTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Clay, Clinton and 26 more67 min
Apr 3, 9:48 AM CDTSevere Thunderstorm WatchSPCBond, Calhoun, Cass, Champaign, Christian, Clark and 32 more6 hr
Apr 3, 11:04 AM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 11 more26 min
Apr 3, 11:51 AM CDTTornado WatchSPCAlexander, Bond, Clark, Clay, Clinton, Crawford and 30 more8 hr
Apr 3, 2:25 PM CDTMesoscale DiscussionSPCAlexander, Bond, Clay, Clinton, Crawford, Edwards and 26 more65 min
Apr 2, 8:05 PM CDTMesoscale DiscussionSPCAtchison, Harrison, Mercer, Nodaway, Putnam, Schuyler and 1 more115 min
Apr 2, 11:40 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, DeKalb, Gentry, Harrison and 3 more65 min
Apr 3, 12:03 AM CDTSevere Thunderstorm WatchSPCAdair, Andrew, Atchison, Buchanan, Caldwell, Clinton and 14 more7 hr
Apr 3, 2:22 AM CDTMesoscale DiscussionSPCAdair, Andrew, Atchison, Buchanan, Caldwell, Clinton and 14 more53 min
Apr 3, 4:28 AM CDTMesoscale DiscussionSPCCarroll, Cass, Chariton, Clay, Cole, Cooper and 12 more62 min
Apr 3, 7:37 AM CDTSevere Thunderstorm WatchSPCAudrain, Bates, Benton, Boone, Callaway, Camden and 30 more8 hr
Apr 3, 2:17 PM CDTMesoscale DiscussionSPCDunklin, Pemiscot118 min
Apr 3, 3:12 PM CDTTornado WatchSPCDunklin, Pemiscot7 hr

Nearby

Mesoscale Discussions in Illinois, 2007Mesoscale Discussions in Missouri, 2007Every mesoscale discussion in 2007

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.