Alert archive / Indiana / Mesoscale Discussions in 2011

Mesoscale Discussion 743

May 11, 201112 counties in Indiana; 5 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 11, 2011, 6:40 PM EDT for 12 counties in Indiana; 5 counties in Michigan. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: May 11, 2011, 6:40 PM EDT (22:40 UTC)
Expired: May 11, 2011, 7:45 PM EDT
In force: 65 min
Issued by: the Storm Prediction Center

Counties Elkhart County, IN, Fulton County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Allegan County, MI, Berrien County, MI, Cass County, MI, Saint Joseph County, MI, Van Buren County, MI

The radar

The Northern Indiana radar (KIWX), 74 km from the middle of the area, began a volume at 22:41 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.

Severe Thunderstorm Watch 286May 11, 6:55 PM EDT

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.7 hours before the alert went out and 239 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: 2360 J/kg
Mixed-layer CIN: -220 J/kg
Mixed-layer LCL: 875 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -68 m²/s²
0-3 km storm-relative helicity: -51 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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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 6:56 PM EDT	Severe Thunderstorm Watch	SPC	Benton, Cass, Elkhart, Fulton, Jasper, Kosciusko and 14 more	5 hr
May 11, 4:19 AM EDT	Mesoscale Discussion	SPC	Delta, Dickinson, Iron, Marquette, Menominee	56 min
May 11, 2:16 PM EDT	Mesoscale Discussion	SPC	Arenac, Bay, Benzie, Clare, Crawford, Gladwin and 14 more	119 min

Nearby

Mesoscale Discussions in Indiana, 2011 Mesoscale Discussions in Michigan, 2011 Every 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.