Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 1814

August 1, 200465 counties in Iowa; 6 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2004, 5:56 AM CDT for 65 counties in Iowa; 6 counties in Minnesota. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Aug 1, 2004, 5:56 AM CDT (10:56 UTC)
Expired
Aug 1, 2004, 7:30 AM CDT
In force
94 min
Issued by
the Storm Prediction Center
All 71 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Boone County, IA, Bremer County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clarke County, IA, Clay County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Ida County, IA, Jasper County, IA, Kossuth County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mills County, IA, Mitchell County, IA, Monroe County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Page County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Webster County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Faribault County, MN, Freeborn County, MN, Jackson County, MN, Martin County, MN, Mower County, MN, Nobles County, MN

The radar

The Des Moines radar (KDMX), 107 km from the middle of the area, began a volume at 10:56 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

Omaha, NE (KOAX), launched 00:00Z, 10.9 hours before the alert went out and 202 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, Omaha, NE at 00:00Z on 2004-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1429 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, Omaha, NE at 00:00Z on 2004-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 square meters per square second.1939Sfc1 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
1429 J/kg
Mixed-layer CIN
-97 J/kg
Mixed-layer LCL
1769 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
282 m²/s²
Significant tornado parameter
0.2
Supercell composite
6.7

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 31, 8:19 PM CDTMesoscale DiscussionSPCDickinson, Emmet, Lyon, Osceola, Winnebago56 min
Jul 31, 9:45 PM CDTSevere Thunderstorm WatchSPCBuena Vista, Cherokee, Clay, Dickinson, Emmet, Hancock and 10 more5 hr
Jul 31, 11:41 PM CDTMesoscale DiscussionSPCBuena Vista, Calhoun, Cerro Gordo, Cherokee, Chickasaw, Clay and 19 more64 min
Aug 1, 1:59 AM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 24 more91 min
Aug 1, 12:11 PM CDTMesoscale DiscussionSPCBuena Vista, Calhoun, Carroll, Cherokee, Crawford, Greene and 3 more64 min
Aug 1, 1:48 PM CDTMesoscale DiscussionSPCBuena Vista, Calhoun, Carroll, Cherokee, Clay, Crawford and 17 more117 min
Aug 1, 2:17 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Clarke, Dallas and 15 more58 min
Aug 1, 3:15 PM CDTTornado WatchSPCBig Stone, Brown, Chippewa, Cottonwood, Douglas, Grant and 21 more7 hr
Aug 1, 3:41 PM CDTMesoscale DiscussionSPCKanabec, Mille Lacs, Morrison, Pine2 hr
Aug 1, 4:00 PM CDTSevere Thunderstorm WatchSPCAitkin, Benton, Chisago, Crow Wing, Isanti, Kanabec and 3 more5 hr

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.