Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 1309

June 29, 201237 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2012, 2:43 PM CDT for 37 counties in Iowa. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jun 29, 2012, 2:43 PM CDT (19:43 UTC)
Expired
Jun 29, 2012, 5:15 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 37 counties

Adair County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Buchanan County, IA, Cedar County, IA, Clarke County, IA, Dallas County, IA, Davis County, IA, Delaware County, IA, Grundy County, IA, Guthrie County, IA, Hardin County, IA, Henry County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Story County, IA, Tama County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA

The radar

The Des Moines radar (KDMX), 74 km from the middle of the area, began a volume at 19:44 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

Davenport, (KDVN), launched 12:00Z, 7.7 hours before the alert went out and 194 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 12:00Z on 2012-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2089 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 12:00Z on 2012-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 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
2089 J/kg
Mixed-layer CIN
-252 J/kg
Mixed-layer LCL
1383 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.1

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 29, 7:59 AM CDTMesoscale DiscussionSPCLyon, Plymouth, Sioux91 min
Jun 29, 3:49 PM CDTSevere Thunderstorm WatchSPCBenton, Cedar, Clinton, Des Moines, Henry, Iowa and 19 more5 hr
Jun 29, 5:04 PM CDTMesoscale DiscussionSPCIowa, Johnson, Poweshiek26 min
Jun 29, 5:35 PM CDTMesoscale DiscussionSPCDickinson, Lyon, Osceola55 min

Nearby

Mesoscale Discussions in Iowa, 2012Every mesoscale discussion in 2012

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.