Alert archive / Illinois / Mesoscale Discussions in 2017

Mesoscale Discussion 267

March 6, 201717 counties in Illinois; 5 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Mar 6, 2017, 10:15 PM CST for 17 counties in Illinois; 5 counties in Wisconsin. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Mar 6, 2017, 10:15 PM CST (04:15 UTC)
Expired: Mar 6, 2017, 11:15 PM CST
In force: 60 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 22 counties

Boone County, IL, DeKalb County, IL, DeWitt County, IL, Ford County, IL, Grundy County, IL, Kane County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, McLean County, IL, Ogle County, IL, Putnam County, IL, Winnebago County, IL, Woodford County, IL, Dane County, WI, Dodge County, WI, Jefferson County, WI, Rock County, WI, Walworth County, WI

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 68Mar 6, 10:35 PM CST

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.3 hours before the alert went out and 134 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: 39 J/kg
Mixed-layer CIN: -343 J/kg
Mixed-layer LCL: 1016 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 407 m²/s²
0-3 km storm-relative helicity: 489 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 6, 7:42 PM CST	Mesoscale Discussion	SPC	Bureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 12 more	63 min
Mar 6, 8:10 PM CST	Mesoscale Discussion	SPC	Alexander	3 hr
Mar 6, 8:22 PM CST	Mesoscale Discussion	SPC	Adams, Bond, Brown, Calhoun, Cass, Christian and 24 more	2 hr
Mar 6, 8:52 PM CST	Tornado Watch	SPC	Adams, Bond, Brown, Bureau, Calhoun, Carroll and 38 more	6 hr
Mar 6, 10:35 PM CST	Severe Thunderstorm Watch	SPC	Boone, Champaign, Christian, Coles, Cook, DeKalb and 25 more	4 hr
Mar 6, 11:13 PM CST	Mesoscale Discussion	SPC	Alexander, Bond, Calhoun, Clay, Clinton, Cumberland and 31 more	2 hr
Mar 7, 1:53 AM CST	Mesoscale Discussion	SPC	Champaign, Coles, Cumberland, Douglas, Edgar, Iroquois and 3 more	97 min
Mar 7, 2:58 AM CST	Mesoscale Discussion	SPC	Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more	92 min
Mar 6, 6:11 PM CST	Mesoscale Discussion	SPC	Buffalo, Burnett, Dunn, Pepin, Pierce, Polk and 1 more	2 hr
Mar 6, 7:00 PM CST	Mesoscale Discussion	SPC	Adams, Barron, Burnett, Chippewa, Clark, Eau Claire and 11 more	2 hr
Mar 6, 7:42 PM CST	Severe Thunderstorm Watch	SPC	Adams, Columbia, Crawford, Dane, Grant, Green and 11 more	5 hr

Nearby

Mesoscale Discussions in Illinois, 2017 Mesoscale Discussions in Wisconsin, 2017 Every mesoscale discussion in 2017

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.