Alert archive / Iowa / Mesoscale Discussions in 2013

Mesoscale Discussion 499

April 17, 20134 counties in Iowa; Scotland County, Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2013, 4:19 PM CDT for 4 counties in Iowa; Scotland County, Missouri. It was in force for 26 min.

The area

The outline as issued.

The facts

Issued: Apr 17, 2013, 4:19 PM CDT (21:19 UTC)
Expired: Apr 17, 2013, 4:45 PM CDT
In force: 26 min
Issued by: the Storm Prediction Center

Counties Des Moines County, IA, Henry County, IA, Lee County, IA, Van Buren County, IA, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 131 km from the middle of the area, began a volume at 21:20 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

Lincoln, IL (KILX), launched 12:00Z, 9.3 hours before the alert went out and 258 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 540 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 186 m²/s²
0-3 km storm-relative helicity: 299 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.8

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.

Issued	Product	Office	Counties	Lasted
Apr 17, 8:49 AM CDT	Mesoscale Discussion	SPC	Appanoose, Clarke, Davis, Decatur, Des Moines, Henry and 15 more	56 min
Apr 17, 9:14 AM CDT	Severe Thunderstorm Watch	SPC	Appanoose, Cedar, Clarke, Clinton, Davis, Decatur and 25 more	10 hr
Apr 17, 1:33 PM CDT	Mesoscale Discussion	SPC	Appanoose, Cedar, Clarke, Clinton, Davis, Decatur and 25 more	57 min
Apr 16, 8:44 PM CDT	Mesoscale Discussion	SPC	Saint Louis, City of Saint Louis	2 hr
Apr 17, 9:50 AM CDT	Mesoscale Discussion	SPC	Barton, Bates, Benton, Boone, Buchanan, Caldwell and 34 more	55 min
Apr 17, 11:11 AM CDT	Tornado Watch	SPC	Audrain, Barry, Barton, Bates, Benton, Boone and 68 more	11 hr
Apr 17, 3:38 PM CDT	Mesoscale Discussion	SPC	Audrain, Barry, Barton, Bates, Benton, Boone and 66 more	97 min
Apr 17, 6:02 PM CDT	Mesoscale Discussion	SPC	Audrain, Barry, Barton, Bates, Benton, Boone and 59 more	88 min

Nearby

Mesoscale Discussions in Iowa, 2013 Mesoscale Discussions in Missouri, 2013 Every mesoscale discussion in 2013

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.