Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 1700

July 22, 201123 counties in Illinois; 25 counties in Iowa; Grant County, Green County, Lafayette County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2011, 7:38 PM CDT for 23 counties in Illinois; 25 counties in Iowa; Grant County, Green County, Lafayette County, Wisconsin. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Jul 22, 2011, 7:38 PM CDT (00:38 UTC)
Expired
Jul 22, 2011, 9:15 PM CDT
In force
97 min
Issued by
the Storm Prediction Center
All 51 counties

Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hardin County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Marshall County, IA, Muscatine County, IA, Scott County, IA, Tama County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Grant County, WI, Green County, WI, Lafayette County, WI

The radar

The Quad Cities radar (KDVN), 87 km from the middle of the area, began a volume at 00:41 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 0.6 hours before the alert went out and 90 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, Davenport, at 00:00Z on 2011-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3095 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, Davenport, at 00:00Z on 2011-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
3095 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
1066 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.5

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 23, 2:18 PM CDTMesoscale DiscussionSPCChampaign, DeWitt, Ford, Iroquois, Kankakee, Livingston and 6 more87 min
Jul 23, 10:14 AM CDTSevere Thunderstorm WatchSPCAllamakee, Howard, Winneshiek4 hr
Jul 23, 1:10 PM CDTMesoscale DiscussionSPCAllamakee, Winneshiek65 min
Jul 23, 1:52 PM CDTMesoscale DiscussionSPCClay, Dickinson, Emmet, Hancock, Kossuth, Lyon and 6 more83 min
Jul 23, 4:57 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Cass, Clarke, Dallas and 26 more93 min
Jul 23, 5:16 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Cass, Clarke, Davis and 25 more4 hr
Jul 23, 4:38 AM CDTMesoscale DiscussionSPCBurnett, Polk67 min
Jul 23, 9:37 AM CDTMesoscale DiscussionSPCAdams, Brown, Buffalo, Calumet, Chippewa, Clark and 25 more53 min
Jul 23, 5:26 PM CDTMesoscale DiscussionSPCAdams, Clark, Eau Claire, Jackson, Juneau, Marathon and 9 more64 min
Jul 23, 6:36 PM CDTSevere Thunderstorm WatchSPCAdams, Clark, Columbia, Dane, Dodge, Fond du Lac and 19 more7 hr

Nearby

Mesoscale Discussions in Iowa, 2011Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Wisconsin, 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.