Alert archive / Illinois / Mesoscale Discussions in 2015

Mesoscale Discussion 259

April 9, 201543 counties in Illinois; Clinton County, Scott County, Iowa; 5 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2015, 6:04 PM CDT for 43 counties in Illinois; Clinton County, Scott County, Iowa; 5 counties in Wisconsin. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Apr 9, 2015, 6:04 PM CDT (23:04 UTC)
Expired
Apr 9, 2015, 7:30 PM CDT
In force
86 min
Issued by
the Storm Prediction Center
All 50 counties

Clinton County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Green County, WI, Kenosha County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Quad Cities radar (KDVN), 85 km from the middle of the area, began a volume at 23:08 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

Davenport, (KDVN), launched 12:00Z, 11.1 hours before the alert went out and 79 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, Davenport, at 12:00Z on 2015-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 101 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, Davenport, at 12:00Z on 2015-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 323 square meters per square second.19395878Sfc1 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
101 J/kg
Mixed-layer CIN
-154 J/kg
Mixed-layer LCL
614 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
323 m²/s²
0-3 km storm-relative helicity
253 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

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 8, 7:04 PM CDTMesoscale DiscussionSPCFranklin, Gallatin, Hardin, Jackson, Johnson, Pope and 3 more116 min
Apr 9, 12:29 PM CDTMesoscale DiscussionSPCBureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 8 more91 min
Apr 9, 12:58 PM CDTTornado WatchSPCAdams, Brown, Carroll, Hancock, Henderson, Henry and 8 more6 hr
Apr 9, 1:48 PM CDTTornado WatchSPCBoone, Bureau, Cass, Champaign, Christian, Cook and 36 more9 hr
Apr 9, 3:12 PM CDTMesoscale DiscussionSPCAdams, Boone, Brown, Bureau, Calhoun, Carroll and 51 more93 min
Apr 9, 3:45 PM CDTMesoscale DiscussionSPCAlexander, Bond, Clay, Clinton, Cumberland, Effingham and 25 more60 min
Apr 9, 4:40 PM CDTTornado WatchSPCBond, Calhoun, Clinton, Fayette, Greene, Jersey and 8 more6 hr
Apr 9, 6:48 PM CDTTornado WatchSPCAlexander, Clark, Clay, Coles, Crawford, Cumberland and 26 more6 hr
Apr 9, 4:46 PM CDTMesoscale DiscussionSPCCalumet, Columbia, Dane, Dodge, Fond du Lac, Green Lake and 6 more89 min
Apr 9, 5:15 PM CDTSevere Thunderstorm WatchSPCColumbia, Dane, Dodge, Fond du Lac, Green Lake, Iowa and 6 more4 hr

Nearby

Mesoscale Discussions in Illinois, 2015Mesoscale Discussions in Wisconsin, 2015Mesoscale Discussions in Iowa, 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.