Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 1673

July 21, 2011Monona County, Iowa; 13 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2011, 2:14 AM CDT for Monona County, Iowa; 13 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 21, 2011, 2:14 AM CDT (07:14 UTC)
Expired
Jul 21, 2011, 4:15 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Monona County, IA, Boone County, NE, Buffalo County, NE, Burt County, NE, Colfax County, NE, Cuming County, NE, Greeley County, NE, Howard County, NE, Madison County, NE, Nance County, NE, Platte County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE

The radar

The Omaha radar (KOAX), 105 km from the middle of the area, began a volume at 07:18 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, 7.2 hours before the alert went out and 105 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 2011-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3756 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 2011-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 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
3756 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1827 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.6

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 21, 3:45 PM CDTMesoscale DiscussionSPCAdair, Adams, Cass, Clarke, Dallas, Fremont and 15 more90 min

Nearby

Mesoscale Discussions in Nebraska, 2011Mesoscale Discussions in Iowa, 2011Every mesoscale discussion in 2011

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.