Alert archive / Illinois / Mesoscale Discussions in 2011
Mesoscale Discussion 739
The Storm Prediction Center issued this mesoscale discussion at May 11, 2011, 3:38 PM CDT for 5 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 11, 2011, 3:38 PM CDT (20:38 UTC)
- Expired
- May 11, 2011, 5:45 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 122 counties
Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Buchanan County, IA, Cedar County, IA, Clayton County, IA, Clinton County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Winneshiek County, IA, Boone County, IL, Brown County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Christian County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL, Woodford County, IL, Houston County, MN, Clark County, MO, Schuyler County, MO, Scotland County, MO, Adams County, WI, Brown County, WI, Calumet County, WI, Clark County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Grant County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, Kenosha County, WI, Kewaunee County, WI, La Crosse County, WI, Lafayette County, WI, Manitowoc County, WI, Marquette County, WI, Milwaukee County, WI, Monroe County, WI, Outagamie County, WI, Ozaukee County, WI, Portage County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI
The radar
The Quad Cities radar (KDVN), 46 km from the middle of the area, began a volume at 20:40 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
Davenport, (KDVN), launched 12:00Z, 8.6 hours before the alert went out and 39 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.
- Mixed-layer CAPE
- 2842 J/kg
- Mixed-layer CIN
- -105 J/kg
- Mixed-layer LCL
- 931 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.6
The text
As transmitted, in the capitals the NWS used until 2016.
035
ACUS11 KWNS 112039
SWOMCD
SPC MCD 112038
WIZ000-ILZ000-IAZ000-MNZ000-MOZ000-112245-
MESOSCALE DISCUSSION 0739
NWS STORM PREDICTION CENTER NORMAN OK
0338 PM CDT WED MAY 11 2011
AREAS AFFECTED...CNTRL/SRN WI...ERN IA...CNTRL/NRN IL
CONCERNING...SEVERE THUNDERSTORM WATCH 281...
VALID 112038Z - 112245Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 281
CONTINUES.
CONVECTION OVER SRN/CNTRL WI IS SHIFTING EWD/NEWD AWAY FROM THE SFC
WARM FRONT...AND HAS LARGELY BECOME ELEVATED AFTER MOVING AWAY FROM
THE SURFACE-BASED UNSTABLE SECTOR NORTH OF THE WARM FRONT. THIS
ACTIVITY WILL CONTINUE TO POSE A THREAT FOR LARGE HAIL AS IT
APPROACHES LAKE MICHIGAN...THOUGH THE THREAT FOR DMGG WINDS WILL
LIKELY DECREASE DUE TO INTERACTION WITH THE STABLE MARINE LAYER
INVOF THE COASTLINE.
THE WARM FRONT EXTENDS TO A SFC MESOLOW OVER SWRN WI. SOUTH OF THIS
FRONT...THE POTENTIAL FOR SFC-BASED SVR MULTICELLULAR STORMS WITH
DMGG WINDS AND LARGE HAIL WILL EVOLVE ACROSS PORTIONS OF NRN AND
CNTRL IL. THIS ACTIVITY IS IN ASSOCIATION WITH A MID-LEVEL IMPULSE
BRUSHING THE MID-MISSISSIPPI VALLEY REGION. TO ADDRESS THIS
ISSUE...WW281 HAS BEEN EXPANDED SWD INTO CNTRL IL UPON LOCAL WFO
COORDINATION.
WEST OF THE MESOLOW...A STATIONARY FRONT /WEAKENED BY EARLIER
CONVECTION OVER IA/ EXTENDS ACROSS NRN IA. HOWEVER...THE EFFECTIVE
BAROCLINIC ZONE WILL CONTINUE TO LIFT NORTHWARD THROUGH LATE
AFTERNOON...AND COULD PROVIDE A FOCUS FOR ADDITIONAL CONVECTION
LATER THIS AFTERNOON IN SWRN PORTIONS OF THE WW. HOWEVER...THE ONSET
OF THIS INITIATION COULD BE DELAYED UNTIL THE SUBSIDENCE IN THE WAKE
OF THE AFOREMENTIONED IMPULSE HAS DEPARTED THAT AREA.
..COHEN.. 05/11/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GRB...LOT...ILX...MKX...LSX...DVN...ARX...DMX...
EAX...
LAT...LON 39598879 39339009 39609070 40219132 40269306 41359279
42229255 43689161 44759074 44758906 44638736 43998737
41498819 40418827 39598879SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 12:55 PM CDT | Mesoscale Discussion | SPC | Boone, Carroll, DeKalb, DuPage, Jo Daviess, Kane and 7 more | 65 min |
| May 11, 1:23 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Carroll, Cass, DeKalb, DeWitt and 33 more | 6 hr |
| May 11, 2:18 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Champaign and 30 more | 57 min |
| May 11, 5:56 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more | 5 hr |
| May 10, 8:45 PM CDT | Mesoscale Discussion | SPC | Allamakee, Howard, Mitchell, Winneshiek, Worth | 90 min |
| May 11, 8:09 AM CDT | Mesoscale Discussion | SPC | Allamakee, Appanoose, Benton, Black Hawk, Bremer, Buchanan and 32 more | 66 min |
| May 11, 2:31 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Carroll, Cass, Crawford and 13 more | 59 min |
| May 11, 2:53 PM CDT | Tornado Watch | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 33 more | 6 hr |
| May 11, 5:03 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 6 more | 57 min |
| May 11, 6:17 PM CDT | Mesoscale Discussion | SPC | Appanoose, Clarke, Davis, Decatur, Jasper, Lucas and 9 more | 28 min |
| May 11, 3:57 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Barton, Bates, Benton, Buchanan and 27 more | 48 min |
| May 11, 4:00 PM CDT | Severe Thunderstorm Watch | SPC | Andrew, Atchison, Barry, Barton, Bates, Buchanan and 35 more | 8 hr |
| May 11, 6:35 PM CDT | Mesoscale Discussion | SPC | Barry, Christian, Dade, Greene, Jasper, Lawrence and 4 more | 55 min |
| May 11, 3:19 AM CDT | Mesoscale Discussion | SPC | Door, Florence, Forest, Kewaunee, Langlade, Marinette and 2 more | 56 min |
| May 11, 1:16 PM CDT | Mesoscale Discussion | SPC | Brown, Door, Forest, Kewaunee, Langlade, Lincoln and 10 more | 119 min |
Nearby
Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Wisconsin, 2011Mesoscale Discussions in Iowa, 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.