Alert archive / Illinois / Mesoscale Discussions in 2018

Mesoscale Discussion 324

May 2, 20184 states

The Storm Prediction Center issued this mesoscale discussion at May 2, 2018, 7:21 PM CDT for 4 states. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
May 2, 2018, 7:21 PM CDT (00:21 UTC)
Expired
May 2, 2018, 8:45 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 50 counties

Cedar County, IA, Clinton County, IA, Des Moines County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henderson County, IL, Henry 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, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Lake County, IN, Newton County, IN, Porter County, IN, Clark County, MO

The radar

The Quad Cities radar (KDVN), 71 km from the middle of the area, began a volume at 00:25 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

Davenport, (KDVN), launched 00:00Z, 0.4 hours before the alert went out and 65 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 00:00Z on 2018-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1023 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 00:00Z on 2018-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 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
1023 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
1402 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
184 m²/s²
Significant tornado parameter
0.3
Supercell composite
5.1

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
May 2, 10:01 PM CDTMesoscale DiscussionSPCBureau, DeKalb, DuPage, Grundy, Henderson, Henry and 18 more89 min
May 2, 10:20 PM CDTMesoscale DiscussionSPCAdams, Calhoun, Pike115 min
May 2, 10:51 PM CDTSevere Thunderstorm WatchSPCCass, Cook, DeKalb, DuPage, Ford, Fulton and 23 more4 hr
May 2, 11:09 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 5 more7 hr
May 3, 1:57 AM CDTMesoscale DiscussionSPCBureau, Cook, DeKalb, DeWitt, DuPage, Ford and 22 more93 min
May 3, 2:32 AM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Macoupin, Madison, Monroe and 3 more88 min
May 2, 8:00 PM CDTMesoscale DiscussionSPCAdams, Appanoose, Clarke, Davis, Decatur, Lucas and 11 more90 min
May 3, 2:36 PM CDTMesoscale DiscussionSPCAdams, Clarke, Decatur, Fremont, Montgomery, Page and 3 more114 min
May 3, 2:57 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Audubon, Cass, Clarke and 24 more6 hr
May 3, 5:58 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Clarke, Dallas and 16 more92 min
May 2, 11:09 PM CDTMesoscale DiscussionSPCMcDonald96 min

Nearby

Mesoscale Discussions in Illinois, 2018Mesoscale Discussions in Iowa, 2018Mesoscale Discussions in Indiana, 2018Every mesoscale discussion in 2018

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.