Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 1310

June 20, 201130 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2011, 1:40 AM CDT for 30 counties in Iowa. It was in force for 35 min.

The area

The outline as issued.

The facts

Issued
Jun 20, 2011, 1:40 AM CDT (06:40 UTC)
Expired
Jun 20, 2011, 2:15 AM CDT
In force
35 min
Issued by
the Storm Prediction Center
All 30 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Decatur County, IA, Greene County, IA, Guthrie County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Page County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA

The radar

The Des Moines radar (KDMX), 61 km from the middle of the area, began a volume at 06:43 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, 6.7 hours before the alert went out and 164 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 2011-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2452 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 2011-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 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
2452 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
1426 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.2

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
Jun 19, 9:16 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Boone, Carroll and 31 more59 min
Jun 19, 9:49 PM CDTTornado WatchSPCFremont, Harrison, Mills, Monona, Montgomery, Page and 2 more6 hr
Jun 19, 11:42 PM CDTSevere Thunderstorm WatchSPCBenton, Cedar, Clinton, Des Moines, Henry, Iowa and 10 more6 hr
Jun 20, 3:27 AM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Boone, Carroll and 28 more33 min
Jun 20, 3:46 AM CDTSevere Thunderstorm WatchSPCAdair, Audubon, Black Hawk, Boone, Calhoun, Carroll and 26 more5 hr
Jun 20, 4:08 AM CDTMesoscale DiscussionSPCBenton, Cedar, Clinton, Davis, Des Moines, Henry and 12 more67 min
Jun 20, 7:29 AM CDTMesoscale DiscussionSPCBlack Hawk, Grundy, Hamilton, Hardin, Jasper, Mahaska and 6 more61 min
Jun 20, 3:08 PM CDTTornado WatchSPCAudubon, Carroll, Cass, Crawford, Fremont, Harrison and 6 more7 hr
Jun 20, 5:55 PM CDTMesoscale DiscussionSPCAdair, Audubon, Boone, Calhoun, Carroll, Dallas and 15 more65 min
Jun 20, 6:17 PM CDTMesoscale DiscussionSPCFremont, Harrison, Mills, Monona, Plymouth, Woodbury58 min
Jun 20, 6:53 PM CDTTornado WatchSPCAdair, Adams, Audubon, Boone, Buena Vista, Calhoun and 41 more6 hr

Nearby

Mesoscale 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.