Alert archive / Illinois / Mesoscale Discussions in 2012

Mesoscale Discussion 2066

October 17, 201218 counties in Illinois; 9 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Oct 17, 2012, 6:19 PM CDT for 18 counties in Illinois; 9 counties in Missouri. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Oct 17, 2012, 6:19 PM CDT (23:19 UTC)
Expired
Oct 17, 2012, 7:15 PM CDT
In force
56 min
Issued by
the Storm Prediction Center
All 27 counties

Bond County, IL, Christian County, IL, Clay County, IL, Clinton County, IL, Effingham County, IL, Fayette County, IL, Jefferson County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Moultrie County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Sangamon County, IL, Shelby County, IL, Washington County, IL, Carter County, MO, Iron County, MO, Madison County, MO, Oregon County, MO, Perry County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Wayne County, MO

The radar

The St Louis radar (KLSX), 79 km from the middle of the area, began a volume at 23:19 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, 11.3 hours before the alert went out and 238 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 12:00Z on 2012-10-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2012-10-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 158 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1209 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
158 m²/s²
0-3 km storm-relative helicity
269 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.

IssuedProductOfficeCountiesLasted
Oct 17, 11:45 AM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 37 more90 min
Oct 17, 1:58 PM CDTSevere Thunderstorm WatchSPCBond, Calhoun, Clinton, Fayette, Greene, Jersey and 8 more6 hr
Oct 17, 5:21 PM CDTTornado WatchSPCAlexander, Franklin, Jackson, Johnson, Massac, Perry and 3 more7 hr
Oct 17, 12:55 PM CDTMesoscale DiscussionSPCBarry, Camden, Cedar, Christian, Cole, Crawford and 29 more95 min
Oct 17, 3:44 PM CDTMesoscale DiscussionSPCDunklin, Pemiscot61 min

Nearby

Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Missouri, 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.