Alert archive / Missouri / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 284

May 11, 201130 counties in Kansas; 41 counties in Missouri

The Storm Prediction Center issued this severe thunderstorm watch at May 11, 2011, 4:00 PM CDT for 30 counties in Kansas; 41 counties in Missouri. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
May 11, 2011, 4:00 PM CDT (21:00 UTC)
Expired
May 11, 2011, 11:36 PM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 71 counties

Allen County, KS, Anderson County, KS, Atchison County, KS, Bourbon County, KS, Brown County, KS, Chautauqua County, KS, Cherokee County, KS, Coffey County, KS, Cowley County, KS, Crawford County, KS, Doniphan County, KS, Douglas County, KS, Elk County, KS, Franklin County, KS, Greenwood County, KS, Jackson County, KS, Jefferson County, KS, Johnson County, KS, Labette County, KS, Leavenworth County, KS, Linn County, KS, Lyon County, KS, Miami County, KS, Montgomery County, KS, Neosho County, KS, Osage County, KS, Shawnee County, KS, Wilson County, KS, Woodson County, KS, Wyandotte County, KS, Andrew County, MO, Atchison County, MO, Barry County, MO, Barton County, MO, Bates County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Cass County, MO, Cedar County, MO, Chariton County, MO, Clay County, MO, Clinton County, MO, Dade County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Henry County, MO, Holt County, MO, Jackson County, MO, Jasper County, MO, Johnson County, MO, Lafayette County, MO, Lawrence County, MO, Linn County, MO, Livingston County, MO, McDonald County, MO, Mercer County, MO, Newton County, MO, Nodaway County, MO, Pettis County, MO, Platte County, MO, Putnam County, MO, Ray County, MO, Saline County, MO, St. Clair County, MO, Sullivan County, MO, Vernon County, MO, Worth County, MO

The radar

The Pleasant Hill radar (KEAX), 62 km from the middle of the area, began a volume at 21:02 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 11, 4:36 PM CDTSevere Thunderstorm WarningICTGreenwood54 min
May 11, 4:55 PM CDTSevere Thunderstorm WarningICTMontgomery37 min
May 11, 5:10 PM CDTSevere Thunderstorm WarningICTGreenwood19 min
May 11, 5:12 PM CDTSevere Thunderstorm WarningTOPCoffey, Lyon33 min
May 11, 5:17 PM CDTSevere Thunderstorm WarningICTWilson25 min
May 11, 5:34 PM CDTSevere Thunderstorm WarningEAXHarrison26 min
May 11, 5:39 PM CDTSevere Thunderstorm WarningEAXHarrison, Mercer21 min
May 11, 6:45 PM CDTSevere Thunderstorm WarningICTLabette, Neosho, Wilson17 min
May 11, 6:50 PM CDTSevere Thunderstorm WarningTOPBrown25 min
May 11, 7:05 PM CDTSevere Thunderstorm WarningSGFCherokee25 min
May 11, 7:13 PM CDTSevere Thunderstorm WarningSGFMcDonald, Newton47 min
May 11, 7:46 PM CDTSevere Thunderstorm WarningSGFBarry, McDonald44 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Topeka, KS (KTOP), launched 12:00Z, 9.0 hours before the alert went out and 68 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, Topeka, KS at 12:00Z on 2011-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2161 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, Topeka, KS at 12:00Z on 2011-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -22 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
2161 J/kg
Mixed-layer CIN
-95 J/kg
Mixed-layer LCL
1016 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
-22 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 11, 7:30 AM CDTMesoscale DiscussionSPCMeade, Seward, Stevens60 min
May 11, 11:21 AM CDTMesoscale DiscussionSPCButler, Chase, Clay, Cloud, Coffey, Dickinson and 22 more84 min
May 11, 12:16 PM CDTSevere Thunderstorm WatchSPCAllen, Anderson, Brown, Butler, Chase, Chautauqua and 48 more5 hr
May 11, 1:51 PM CDTMesoscale DiscussionSPCClark, Comanche, Edwards, Finney, Ford, Gove and 25 more84 min
May 11, 3:57 PM CDTMesoscale DiscussionSPCAllen, Anderson, Atchison, Bourbon, Brown, Cherokee and 25 more48 min
May 11, 4:52 PM CDTTornado WatchSPCCheyenne, Decatur, Gove, Graham, Logan, Norton and 7 more6 hr
May 11, 6:02 PM CDTMesoscale DiscussionSPCBarber, Barton, Clark, Comanche, Edwards, Ellis and 9 more88 min
May 11, 6:35 PM CDTMesoscale DiscussionSPCCherokee, Labette55 min
May 11, 8:09 AM CDTMesoscale DiscussionSPCAdair, Grundy, Knox, Linn, Macon, Mercer and 4 more66 min
May 11, 2:18 PM CDTMesoscale DiscussionSPCLincoln, Pike, Saint Charles, Saint Louis, City of Saint Louis57 min
May 11, 3:38 PM CDTMesoscale DiscussionSPCClark, Schuyler, Scotland2 hr
May 11, 6:17 PM CDTMesoscale DiscussionSPCAdair, Grundy, Knox, Macon, Mercer, Putnam and 3 more28 min

Nearby

Severe Thunderstorm Watches in Missouri, 2011Severe Thunderstorm Watches in Kansas, 2011Every severe thunderstorm watch 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.