Alert archive / Nebraska / Mesoscale Discussions in 2008

Mesoscale Discussion 1834

July 20, 2008Harrison County, Monona County, Iowa; 24 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2008, 11:10 PM CDT for Harrison County, Monona County, Iowa; 24 counties in Nebraska. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Jul 20, 2008, 11:10 PM CDT (04:10 UTC)
Expired
Jul 21, 2008, 12:45 AM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 26 counties

Harrison County, IA, Monona County, IA, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Garfield County, NE, Greeley County, NE, Madison County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Saunders County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE

The radar

The Omaha radar (KOAX), 126 km from the middle of the area, began a volume at 04:12 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, 4.2 hours before the alert went out and 125 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 2008-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3989 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 2008-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 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
3989 J/kg
Mixed-layer CIN
-58 J/kg
Mixed-layer LCL
1202 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
306 m²/s²
Significant tornado parameter
3.7
Supercell composite
26.4

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 20, 8:58 PM CDTSevere Thunderstorm WatchSPCBuena Vista, Cherokee, Crawford, Harrison, Ida, Monona and 5 more7 hr
Jul 20, 10:17 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Benton, Boone and 50 more2 hr
Jul 20, 11:25 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Audubon, Benton, Black Hawk and 54 more8 hr
Jul 21, 3:10 AM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Benton, Black Hawk and 54 more95 min
Jul 21, 4:01 AM CDTMesoscale DiscussionSPCPlymouth, Sioux89 min
Jul 21, 4:21 AM CDTSevere Thunderstorm WatchSPCBenton, Cedar, Des Moines, Henry, Iowa, Jefferson and 9 more8 hr
Jul 21, 1:48 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Cass, Clarke, Davis and 23 more87 min
Jul 21, 5:10 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Audubon, Cass, Clarke and 32 more7 hr
Jul 20, 7:58 PM CDTMesoscale DiscussionSPCAntelope, Blaine, Boyd, Brown, Cedar, Cherry and 14 more92 min

Nearby

Mesoscale Discussions in Nebraska, 2008Mesoscale Discussions in Iowa, 2008Every mesoscale discussion in 2008

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.