Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 1503

July 17, 2007Rock Island County, Illinois; 32 counties in Iowa; 6 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jul 17, 2007, 2:53 AM CDT for Rock Island County, Illinois; 32 counties in Iowa; 6 counties in Minnesota. It was in force for 82 min.

The area

The outline as issued.

The facts

Issued
Jul 17, 2007, 2:53 AM CDT (07:53 UTC)
Expired
Jul 17, 2007, 4:15 AM CDT
In force
82 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
All 39 counties

Allamakee County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Cerro Gordo 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, Howard County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Louisa County, IA, Mitchell County, IA, Muscatine County, IA, Scott County, IA, Tama County, IA, Washington County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Rock Island County, IL, Dodge County, MN, Fillmore County, MN, Freeborn County, MN, Mower County, MN, Olmsted County, MN, Steele County, MN

The radar

The La Crosse radar (KARX), 150 km from the middle of the area, began a volume at 07:54 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 00:00Z, 7.9 hours before the alert went out and 164 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 2007-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 405 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 2007-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 211 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
405 J/kg
Mixed-layer CIN
-77 J/kg
Mixed-layer LCL
1277 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
211 m²/s²
0-3 km storm-relative helicity
243 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.4

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 16, 9:50 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, DuPage, Grundy and 21 more85 min
Jul 17, 4:37 AM CDTSevere Thunderstorm WatchSPCHenry, Mercer, Rock Island, Whiteside3 hr
Jul 17, 6:58 AM CDTMesoscale DiscussionSPCBureau, Cass, DeWitt, Fulton, Grundy, Henderson and 17 more92 min
Jul 17, 10:52 AM CDTMesoscale DiscussionSPCBond, Calhoun, Clark, Clay, Clinton, Coles and 32 more83 min
Jul 17, 1:25 PM CDTSevere Thunderstorm WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more6 hr
Jul 17, 1:33 PM CDTMesoscale DiscussionSPCBureau, Carroll, Henry, Jo Daviess, Knox, Mercer and 5 more117 min
Jul 17, 3:34 PM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more86 min
Jul 16, 7:39 PM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 50 more96 min
Jul 17, 5:55 PM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 19 more95 min

Nearby

Mesoscale Discussions in Iowa, 2007Mesoscale Discussions in Minnesota, 2007Mesoscale Discussions in Illinois, 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.