Alert archive / Illinois / Mesoscale Discussions in 2015

Mesoscale Discussion 458

April 25, 20155 states

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2015, 3:25 PM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 25, 2015, 3:25 PM CDT (20:25 UTC)
Expired
Apr 25, 2015, 5:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 71 counties

Alexander County, IL, Bond County, IL, Clay County, IL, Clinton County, IL, Edwards County, IL, Fayette County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Lawrence County, IL, Madison County, IL, Marion County, IL, Massac County, IL, Monroe County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Pike County, IN, Posey County, IN, Vanderburgh County, IN, Warrick County, IN, Ballard County, KY, Caldwell County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Daviess County, KY, Henderson County, KY, Hopkins County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McLean County, KY, Muhlenberg County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Perry County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Warren County, MO, Washington County, MO, Montgomery County, TN

The radar

The Paducah radar (KPAH), 78 km from the middle of the area, began a volume at 20:26 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, 8.4 hours before the alert went out and 265 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 2015-04-25Temperature 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 2015-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 square meters per square second.1939587897117Sfc1 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
735 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
137 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
Apr 25, 12:22 PM CDTMesoscale DiscussionSPCAlexander, Clinton, Edwards, Franklin, Gallatin, Hamilton and 20 more2 hr
Apr 25, 12:55 PM CDTTornado WatchSPCAlexander, Bond, Calhoun, Clay, Clinton, Edwards and 30 more7 hr
Apr 25, 4:57 PM CDTSevere Thunderstorm WatchSPCAdair, Allen, Barren, Bell, Boyle, Breckinridge and 40 more6 hr
Apr 25, 6:14 PM CDTMesoscale DiscussionSPCAdair, Allen, Barren, Boyle, Butler, Casey and 29 more91 min

Nearby

Mesoscale Discussions in Illinois, 2015Mesoscale Discussions in Kentucky, 2015Mesoscale Discussions in Missouri, 2015Every mesoscale discussion in 2015

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.