Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 1918

August 28, 200725 counties in Iowa; Otoe County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2007, 8:17 PM CDT for 25 counties in Iowa; Otoe County, Nebraska. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued
Aug 28, 2007, 8:17 PM CDT (01:17 UTC)
Expired
Aug 28, 2007, 9:15 PM CDT
In force
58 min
Issued by
the Storm Prediction Center
All 26 counties

Adair County, IA, Adams County, IA, Benton County, IA, Cedar County, IA, Clinton County, IA, Dallas County, IA, Delaware County, IA, Dubuque County, IA, Fremont County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Madison County, IA, Marion County, IA, Marshall County, IA, Montgomery County, IA, Page County, IA, Polk County, IA, Poweshiek County, IA, Tama County, IA, Union County, IA, Warren County, IA, Otoe County, NE

The radar

The Des Moines radar (KDMX), 58 km from the middle of the area, began a volume at 01:20 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

Davenport, (KDVN), launched 00:00Z, 1.3 hours before the alert went out and 211 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, Davenport, at 00:00Z on 2007-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1395 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, Davenport, at 00:00Z on 2007-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 65 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
1395 J/kg
Mixed-layer CIN
-72 J/kg
Mixed-layer LCL
1610 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

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
Aug 28, 7:12 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 19 more63 min

Nearby

Mesoscale Discussions in Iowa, 2007Mesoscale Discussions in Nebraska, 2007Every mesoscale discussion in 2007

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.