Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 1870

August 3, 200415 counties in Iowa; 18 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2004, 9:16 PM CDT for 15 counties in Iowa; 18 counties in Nebraska. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Aug 3, 2004, 9:16 PM CDT (02:16 UTC)
Expired
Aug 3, 2004, 10:15 PM CDT
In force
59 min
Issued by
the Storm Prediction Center
All 33 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Fremont County, IA, Guthrie County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Burt County, NE, Butler County, NE, Cass County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Lancaster County, NE, Madison County, NE, Otoe County, NE, Platte County, NE, Polk County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Washington County, NE, York County, NE

The radar

The Omaha radar (KOAX), 68 km from the middle of the area, began a volume at 02:16 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

Topeka, KS (KTOP), launched 00:00Z, 2.3 hours before the alert went out and 248 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, Topeka, KS at 00:00Z on 2004-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4543 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, Topeka, KS at 00:00Z on 2004-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 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
4543 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
1505 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
284 m²/s²
Significant tornado parameter
1.4
Supercell composite
14.3

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
Aug 3, 8:19 PM CDTMesoscale DiscussionSPCAppanoose, Benton, Boone, Cedar, Clarke, Clinton and 33 more56 min
Aug 3, 9:45 PM CDTSevere Thunderstorm WatchSPCAdams, Appanoose, Clarke, Davis, Decatur, Des Moines and 18 more5 hr
Aug 3, 11:34 PM CDTMesoscale DiscussionSPCAppanoose, Davis, Lee86 min
Aug 4, 1:42 AM CDTMesoscale DiscussionSPCAdams, Appanoose, Clarke, Davis, Decatur, Des Moines and 17 more2 hr
Aug 4, 4:22 PM CDTMesoscale DiscussionSPCBanner, Box Butte, Dawes, Kimball, Scotts Bluff, Sioux2 hr

Nearby

Mesoscale Discussions in Nebraska, 2004Mesoscale Discussions in Iowa, 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.