Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 1641

July 13, 200428 counties in Iowa; 4 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2004, 4:21 AM CDT for 28 counties in Iowa; 4 counties in Minnesota. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Jul 13, 2004, 4:21 AM CDT (09:21 UTC)
Expired
Jul 13, 2004, 5:15 AM CDT
In force
54 min
Issued by
the Storm Prediction Center
All 32 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, Mitchell County, IA, Tama County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Fillmore County, MN, Freeborn County, MN, Mower County, MN, Olmsted County, MN

The radar

The La Crosse radar (KARX), 152 km from the middle of the area, began a volume at 09:24 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

Minneapolis, MN (KMPX), launched 00:00Z, 9.4 hours before the alert went out and 281 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, Minneapolis, MN at 00:00Z on 2004-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1267 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, Minneapolis, MN at 00:00Z on 2004-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 47 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
1267 J/kg
Mixed-layer CIN
-73 J/kg
Mixed-layer LCL
1215 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
47 m²/s²
0-3 km storm-relative helicity
174 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.1

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 12, 9:15 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Boone, Buena Vista, Calhoun and 32 more7 hr
Jul 12, 9:19 PM CDTMesoscale DiscussionSPCClay, Dickinson, Emmet, Hancock, Kossuth, Lyon and 5 more116 min
Jul 12, 11:19 PM CDTMesoscale DiscussionSPCAdair, Adams, Cass, Decatur, Fremont, Mills and 6 more116 min
Jul 12, 11:52 PM CDTMesoscale DiscussionSPCCherokee, Dickinson, Lyon, O'Brien, Osceola, Plymouth and 1 more53 min
Jul 13, 12:55 AM CDTSevere Thunderstorm WatchSPCAdair, Audubon, Benton, Black Hawk, Boone, Bremer and 52 more6 hr
Jul 13, 10:32 AM CDTMesoscale DiscussionSPCCedar, Clinton, Delaware, Dubuque, Jackson, Johnson and 4 more118 min
Jul 13, 10:55 AM CDTTornado WatchSPCCedar, Clinton, Delaware, Dubuque, Jackson, Jones and 3 more6 hr
Jul 13, 1:39 PM CDTMesoscale DiscussionSPCCedar, Clinton, Delaware, Dubuque, Jackson, Jones and 3 more66 min
Jul 13, 2:25 PM CDTSevere Thunderstorm WatchSPCFremont, Harrison, Mills, Monona, Pottawattamie, Shelby6 hr
Jul 12, 9:50 PM CDTSevere Thunderstorm WatchSPCBecker, Big Stone, Blue Earth, Brown, Chippewa, Clay and 38 more6 hr
Jul 13, 1:20 AM CDTSevere Thunderstorm WatchSPCAitkin, Benton, Carlton, Cass, Chisago, Crow Wing and 6 more6 hr
Jul 13, 3:35 AM CDTMesoscale DiscussionSPCAnoka, Benton, Carver, Chippewa, Chisago, Hennepin and 20 more55 min

Nearby

Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Minnesota, 2004Every mesoscale discussion in 2004

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.