Alert archive / Iowa / Mesoscale Discussions in 2007

Mesoscale Discussion 309

March 21, 20074 states

The Storm Prediction Center issued this mesoscale discussion at Mar 21, 2007, 9:31 PM CDT for 4 states. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Mar 21, 2007, 9:31 PM CDT (02:31 UTC)
Expired
Mar 21, 2007, 10:30 PM CDT
In force
59 min
Issued by
the Storm Prediction Center
All 41 counties

Adair County, IA, Adams County, IA, Boone County, IA, Butler County, IA, Calhoun County, IA, Cerro Gordo County, IA, Clarke County, IA, Dallas County, IA, Decatur County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Madison County, IA, Page County, IA, Polk County, IA, Ringgold County, IA, Story County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Webster County, IA, Wright County, IA, Brown County, KS, Doniphan County, KS, Nemaha County, KS, Andrew County, MO, Atchison County, MO, DeKalb County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Nemaha County, NE, Pawnee County, NE, Richardson County, NE

The radar

The Des Moines radar (KDMX), 55 km from the middle of the area, began a volume at 02:31 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

Omaha, NE (KOAX), launched 00:00Z, 2.5 hours before the alert went out and 174 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 2007-03-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 942 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 2007-03-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 111 square meters per square second.19395878Sfc1 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
942 J/kg
Mixed-layer CIN
-112 J/kg
Mixed-layer LCL
1009 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
253 m²/s²
Significant tornado parameter
0.6
Supercell composite
6.3

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
Mar 21, 10:24 PM CDTSevere Thunderstorm WatchSPCAppanoose, Clarke, Davis, Decatur, Lucas, Monroe and 4 more4 hr
Mar 22, 12:52 AM CDTMesoscale DiscussionSPCAppanoose, Clarke, Davis, Decatur, Lucas, Monroe and 4 more53 min
Mar 22, 2:02 AM CDTMesoscale DiscussionSPCCedar, Des Moines, Henry, Iowa, Jefferson, Johnson and 7 more118 min
Mar 22, 3:23 AM CDTMesoscale DiscussionSPCAllen, Anderson, Barber, Bourbon, Butler, Chase and 28 more67 min
Mar 22, 1:59 PM CDTMesoscale DiscussionSPCBarber, Butler, Chautauqua, Cowley, Elk, Greenwood and 9 more2 hr
Mar 22, 2:49 AM CDTMesoscale DiscussionSPCAudrain, Boone, Callaway, Carroll, Chariton, Cole and 21 more26 min
Mar 22, 2:59 AM CDTTornado WatchSPCAudrain, Boone, Callaway, Chariton, Cole, Cooper and 18 more7 hr
Mar 22, 6:13 AM CDTMesoscale DiscussionSPCAudrain, Benton, Boone, Callaway, Camden, Cole and 20 more62 min

Nearby

Mesoscale Discussions in Iowa, 2007Mesoscale Discussions in Missouri, 2007Mesoscale Discussions in Kansas, 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.