Alert archive / Illinois / Mesoscale Discussions in 2017

Mesoscale Discussion 598

April 29, 201731 counties in Illinois; 29 counties in Indiana; 6 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2017, 6:30 PM CDT for 31 counties in Illinois; 29 counties in Indiana; 6 counties in Missouri. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued
Apr 29, 2017, 6:30 PM CDT (23:30 UTC)
Expired
Apr 29, 2017, 7:30 PM CDT
In force
60 min
Issued by
the Storm Prediction Center
All 66 counties

Alexander County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Hamilton County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Johnson County, IL, Lawrence County, IL, Marion County, IL, Moultrie County, IL, Perry County, IL, Randolph County, IL, Richland County, IL, Saline County, IL, Shelby County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Bartholomew County, IN, Brown County, IN, Clay County, IN, Daviess County, IN, Dubois County, IN, Gibson County, IN, Greene County, IN, Hancock County, IN, Hendricks County, IN, Jackson County, IN, Jennings County, IN, Johnson County, IN, Knox County, IN, Lawrence County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Orange County, IN, Owen County, IN, Parke County, IN, Pike County, IN, Putnam County, IN, Shelby County, IN, Sullivan County, IN, Vermillion County, IN, Vigo County, IN, Washington County, IN, Bollinger County, MO, Cape Girardeau County, MO, Madison County, MO, Perry County, MO, Sainte Genevieve County, MO, Wayne County, MO

The radar

The Evansville,IN radar (KVWX), 68 km from the middle of the area, began a volume at 23:30 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, 11.5 hours before the alert went out and 161 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 2017-04-29Temperature 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 2017-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 242 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
776 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
242 m²/s²
0-3 km storm-relative helicity
568 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
Apr 28, 10:01 PM CDTSevere Thunderstorm WatchSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 7 more9 hr
Apr 28, 11:55 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hardin, Jackson, Johnson and 6 more95 min
Apr 29, 3:39 AM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more96 min
Apr 29, 12:50 PM CDTMesoscale DiscussionSPCMonroe, Randolph, Saint Clair85 min
Apr 29, 3:28 PM CDTMesoscale DiscussionSPCBond, Clay, Clinton, Crawford, Edwards, Effingham and 20 more2 hr
Apr 29, 3:57 PM CDTSevere Thunderstorm WatchSPCAlexander, Bond, Christian, Clark, Clay, Clinton and 38 more6 hr
Apr 28, 7:10 PM CDTSevere Thunderstorm WatchSPCBartholomew, Brown, Dearborn, Decatur, Fayette, Franklin and 8 more6 hr
Apr 28, 8:27 PM CDTTornado WatchSPCClark, Crawford, Dubois, Floyd, Gibson, Harrison and 10 more5 hr
Apr 28, 10:19 PM CDTMesoscale DiscussionSPCClark, Crawford, Daviess, Dearborn, Dubois, Floyd and 18 more116 min
Apr 29, 12:50 AM CDTMesoscale DiscussionSPCClark, Crawford, Dubois, Floyd, Gibson, Harrison and 11 more85 min
Apr 29, 6:23 AM CDTMesoscale DiscussionSPCClark, Dearborn, Floyd, Harrison, Jackson, Jefferson and 6 more3 hr

Nearby

Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Indiana, 2017Mesoscale Discussions in Missouri, 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.