Alert archive / Illinois / Mesoscale Discussions in 2017

Mesoscale Discussion 265

March 6, 201730 counties in Illinois; Lee County, Iowa; 25 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Mar 6, 2017, 8:22 PM CST for 30 counties in Illinois; Lee County, Iowa; 25 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 6, 2017, 8:22 PM CST (02:22 UTC)
Expired
Mar 6, 2017, 10:45 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 56 counties

Lee County, IA, Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Henderson County, IL, Jersey County, IL, Logan County, IL, Macoupin County, IL, Madison County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Tazewell County, IL, Warren County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Clark County, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shelby County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 79 km from the middle of the area, began a volume at 02:27 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

Lincoln, IL (KILX), launched 00:00Z, 2.4 hours before the alert went out and 201 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, Lincoln, IL at 00:00Z on 2017-03-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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, Lincoln, IL at 00:00Z on 2017-03-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 475 square meters per square second.1939587897Sfc1 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
4 J/kg
Mixed-layer CIN
-285 J/kg
Mixed-layer LCL
651 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
475 m²/s²
0-3 km storm-relative helicity
484 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.

IssuedProductOfficeCountiesLasted
Mar 6, 7:42 PM CSTMesoscale DiscussionSPCBureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 12 more63 min
Mar 6, 8:10 PM CSTMesoscale DiscussionSPCAlexander3 hr
Mar 6, 8:52 PM CSTTornado WatchSPCAdams, Bond, Brown, Bureau, Calhoun, Carroll and 38 more6 hr
Mar 6, 10:15 PM CSTMesoscale DiscussionSPCBoone, DeKalb, DeWitt, Ford, Grundy, Kane and 11 more60 min
Mar 6, 10:35 PM CSTSevere Thunderstorm WatchSPCBoone, Champaign, Christian, Coles, Cook, DeKalb and 25 more4 hr
Mar 6, 11:13 PM CSTMesoscale DiscussionSPCAlexander, Bond, Calhoun, Clay, Clinton, Cumberland and 31 more2 hr
Mar 7, 1:53 AM CSTMesoscale DiscussionSPCChampaign, Coles, Cumberland, Douglas, Edgar, Iroquois and 3 more97 min
Mar 7, 2:58 AM CSTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more92 min
Mar 6, 6:11 PM CSTMesoscale DiscussionSPCAdair, Adams, Allamakee, Appanoose, Audubon, Benton and 57 more2 hr
Mar 6, 6:02 PM CSTMesoscale DiscussionSPCBarry, Barton, Bates, Benton, Camden, Cedar and 22 more58 min
Mar 6, 6:31 PM CSTMesoscale DiscussionSPCAdair, Andrew, Bates, Benton, Buchanan, Caldwell and 32 more119 min
Mar 6, 6:51 PM CSTTornado WatchSPCBarry, Barton, Benton, Camden, Cedar, Christian and 28 more8 hr
Mar 6, 7:19 PM CSTMesoscale DiscussionSPCBuchanan, Caldwell, Carroll, Cass, Chariton, Clay and 15 more116 min
Mar 6, 9:16 PM CSTMesoscale DiscussionSPCBarry, McDonald119 min
Mar 6, 9:21 PM CSTTornado WatchSPCBollinger, Butler, Cape Girardeau, Carter, Dunklin, Perry and 3 more8 hr
Mar 7, 3:37 AM CSTSevere Thunderstorm WatchSPCPemiscot8 hr

Nearby

Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Iowa, 2017Every 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; radar from the NEXRAD Level II archive.