Alert archive / Missouri / Mesoscale Discussions in 2011

Mesoscale Discussion 959

May 25, 20116 counties in Illinois; 8 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 25, 2011, 2:32 PM CDT for 6 counties in Illinois; 8 counties in Missouri. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued
May 25, 2011, 2:32 PM CDT (19:32 UTC)
Expired
May 25, 2011, 3:30 PM CDT
In force
58 min
Issued by
the Storm Prediction Center

Counties Calhoun County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Pike County, IL, Scott County, IL, Audrain County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO

The radar

The St Louis radar (KLSX), 68 km from the middle of the area, began a volume at 19:34 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, 7.5 hours before the alert went out and 236 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 2011-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1832 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 2011-05-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 253 square meters per square second.19395878Sfc1 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
1832 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
561 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
253 m²/s²
0-3 km storm-relative helicity
222 m²/s²
Significant tornado parameter
1.6
Supercell composite
10.1

Open this sounding in Storm Lab

The text

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

999 
ACUS11 KWNS 251932
SWOMCD
SPC MCD 251932 
ILZ000-MOZ000-252030-

MESOSCALE DISCUSSION 0959
NWS STORM PREDICTION CENTER NORMAN OK
0232 PM CDT WED MAY 25 2011

AREAS AFFECTED...E-CNTRL MO...W-CNTRL IL

CONCERNING...TORNADO WATCH 369...370...

VALID 251932Z - 252030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 369...370...CONTINUES.

DISCRETE SUPERCELLS HAVE BEGUN TO INTERACT WITH THE RETREATING
SURFACE OUTFLOW BOUNDARY EXTENDING ACROSS EAST CENTRAL MO AND WEST
CENTRAL IL.  STRONG HEATING HAS OCCURRED TO THE NORTH OF
BOUNDARY...WHERE DEWPOINTS IN THE UPPER 60S ARE YIELDING MLCAPE
VALUES OVER 2000 J/KG.  BACKED LOW LEVEL WINDS AND LOCALLY ENHANCED
VORTICITY ALONG REMNANT BOUNDARY ARE LIKELY AIDING SUPERCELL
STRUCTURES.  LATEST SURFACE ANALYSIS ALSO HINTS AT A WEAK SURFACE
MESOLOW NEAR COU...CONTRIBUTING TO ENHANCED LOW LEVEL SHEAR AND
PRESSURE FALLS ALONG THE BOUNDARY.  STORMS NOW OVER
AUDRAIN/MONTGOMERY/LINCOLN COUNTIES MO ARE SHOWING SIGNIFICANT
ROTATION WITH AN ENHANCED RISK OF TORNADOES.  THE THREAT OF
TORNADOES AND VERY LARGE HAIL WILL PERSIST IN THIS ZONE FOR THE NEXT
FEW HOURS AS DISCRETE STORMS FORM TO THE SOUTH AND TRACK ACROSS THE
RETREATING BOUNDARY...INCLUDING PORTIONS OF THE STL METRO AREA.

..HART.. 05/25/2011

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

ATTN...WFO...ILX...LSX...

LAT...LON   39059197 39359216 39829175 39749073 39489009 39068969
            38629013 38859127 39059197

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 25, 12:48 AM CDTMesoscale DiscussionSPCAdams, Alexander, Bond, Brown, Calhoun, Cass and 23 more57 min
May 25, 1:22 AM CDTTornado WatchSPCAdams, Brown, Calhoun, Cass, Fulton, Greene and 16 more7 hr
May 25, 4:58 AM CDTMesoscale DiscussionSPCBond, Brown, Calhoun, Cass, Champaign, Christian and 45 more92 min
May 25, 5:46 AM CDTTornado WatchSPCBond, Champaign, Christian, Clark, Clay, Clinton and 35 more7 hr
May 25, 7:31 AM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more59 min
May 25, 7:48 AM CDTMesoscale DiscussionSPCChampaign, Clark, Clay, Clinton, Coles, Crawford and 18 more87 min
May 25, 8:33 AM CDTMesoscale DiscussionSPCChampaign, DeWitt, Douglas, Edgar, Ford, Iroquois and 3 more87 min
May 25, 10:18 AM CDTMesoscale DiscussionSPCBond, Clark, Clay, Clinton, Crawford, Cumberland and 12 more57 min
May 25, 10:37 AM CDTTornado WatchSPCAdams, Brown, Pike7 hr
May 25, 11:02 AM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 13 more28 min
May 25, 11:09 AM CDTTornado Watch PDSSPCAlexander, Bond, Calhoun, Christian, Clark, Clay and 41 more10 hr
May 25, 2:31 PM CDTTornado WatchSPCBureau, Cass, Champaign, DeKalb, DeWitt, Ford and 33 more7 hr
May 25, 3:10 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hardin, Jackson, Johnson and 6 more95 min
May 25, 5:48 PM CDTMesoscale DiscussionSPCBureau, Champaign, DeKalb, DeWitt, Douglas, Ford and 19 more117 min
May 25, 6:25 PM CDTMesoscale DiscussionSPCAlexander, Clay, Clinton, Edwards, Franklin, Gallatin and 20 more2 hr
May 24, 7:07 PM CDTMesoscale DiscussionSPCAndrew, Barton, Bates, Buchanan, Cass, Cedar and 14 more53 min
May 24, 7:26 PM CDTTornado WatchSPCAdair, Barry, Barton, Bates, Benton, Buchanan and 48 more7 hr
May 24, 7:42 PM CDTMesoscale DiscussionSPCMcDonald63 min
May 24, 11:24 PM CDTMesoscale DiscussionSPCBenton, Camden, Christian, Cooper, Dallas, Douglas and 15 more96 min
May 25, 9:54 AM CDTMesoscale DiscussionSPCBenton, Butler, Camden, Carter, Christian, Dallas and 24 more96 min
May 25, 11:52 AM CDTMesoscale DiscussionSPCDunklin, Pemiscot83 min
May 25, 12:28 PM CDTTornado Watch PDSSPCDunklin, Pemiscot8 hr
May 25, 1:28 PM CDTMesoscale DiscussionSPCAdair, Audrain, Boone, Caldwell, Callaway, Camden and 44 more92 min
May 25, 2:56 PM CDTMesoscale DiscussionSPCDunklin, Pemiscot94 min
May 25, 5:56 PM CDTMesoscale DiscussionSPCDunklin, Pemiscot64 min

Nearby

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