Alert archive / Illinois / Mesoscale Discussions in 2017

Mesoscale Discussion 475

April 10, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Apr 10, 2017, 11:57 AM CDT for 4 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Apr 10, 2017, 11:57 AM CDT (16:57 UTC)
Expired
Apr 10, 2017, 2:30 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 48 counties

Boone County, IL, Bureau County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy 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, Marshall County, IL, McHenry County, IL, McLean County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Stark County, IL, Tazewell County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Elkhart County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Allegan County, MI, Berrien County, MI, Cass County, MI, Kalamazoo County, MI, Van Buren County, MI, Kenosha County, WI, Milwaukee County, WI, Racine County, WI, Walworth County, WI

The radar

The Chicago radar (KLOT), 9 km from the middle of the area, began a volume at 17:00 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 12:00Z, 5.0 hours before the alert went out and 177 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 2017-04-10Temperature 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 2017-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -63 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1373 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
-63 m²/s²
0-3 km storm-relative helicity
3 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 10, 1:53 AM CDTMesoscale DiscussionSPCBureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 9 more2 hr
Apr 10, 1:48 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cass, Champaign, Christian and 48 more8 hr
Apr 10, 3:25 PM CDTMesoscale DiscussionSPCBond, Boone, Bureau, Cass, Champaign, Christian and 54 more2 hr
Apr 10, 6:22 PM CDTMesoscale DiscussionSPCChampaign, Christian, Coles, Cook, DeWitt, Douglas and 19 more53 min
Apr 10, 12:01 AM CDTSevere Thunderstorm WatchSPCDickinson, Iron, Marquette3 hr
Apr 10, 2:16 AM CDTMesoscale DiscussionSPCAlger, Delta, Dickinson, Marquette, Menominee, Schoolcraft119 min
Apr 9, 8:06 PM CDTMesoscale DiscussionSPCBarron, Buffalo, Chippewa, Clark, Dunn, Eau Claire and 8 more54 min
Apr 9, 9:01 PM CDTSevere Thunderstorm WatchSPCBuffalo, Chippewa, Clark, Dunn, Eau Claire, Jackson and 3 more4 hr
Apr 9, 11:32 PM CDTMesoscale DiscussionSPCAdams, Buffalo, Chippewa, Clark, Dunn, Eau Claire and 25 more58 min

Nearby

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