Alert archive / Iowa / Mesoscale Discussions in 2009

Mesoscale Discussion 734

May 6, 200914 counties in Iowa; 9 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at May 6, 2009, 1:55 PM CDT for 14 counties in Iowa; 9 counties in Minnesota. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
May 6, 2009, 1:55 PM CDT (18:55 UTC)
Expired
May 6, 2009, 3:00 PM CDT
In force
65 min
Issued by
the Storm Prediction Center
All 23 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Ida County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sac County, IA, Sioux County, IA, Woodbury County, IA, Brown County, MN, Cottonwood County, MN, Jackson County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Redwood County, MN, Renville County, MN, Watonwan County, MN

The radar

The Sioux Falls radar (KFSD), 130 km from the middle of the area, began a volume at 18:58 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 12:00Z, 6.9 hours before the alert went out and 209 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 12:00Z on 2009-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 174 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 12:00Z on 2009-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 126 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
174 J/kg
Mixed-layer CIN
-271 J/kg
Mixed-layer LCL
633 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
130 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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Nearby

Mesoscale Discussions in Iowa, 2009Mesoscale Discussions in Minnesota, 2009Every mesoscale discussion in 2009

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.