Alert archive / Illinois / Mesoscale Discussions in 2018

Mesoscale Discussion 314

May 2, 201829 counties in Illinois; 15 counties in Iowa; Clark County, Missouri

The Storm Prediction Center issued this mesoscale discussion at May 2, 2018, 1:33 PM CDT for 29 counties in Illinois; 15 counties in Iowa; Clark County, Missouri. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
May 2, 2018, 1:33 PM CDT (18:33 UTC)
Expired
May 2, 2018, 3:30 PM CDT
In force
117 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 45 counties

Cedar County, IA, Clinton County, IA, Des Moines County, IA, Henry County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Bureau County, IL, Carroll County, IL, DeKalb County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL, Woodford County, IL, Clark County, MO

The radar

The Quad Cities radar (KDVN), 55 km from the middle of the area, began a volume at 18:33 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 12:00Z, 6.6 hours before the alert went out and 54 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 2018-05-02Temperature 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, Davenport, at 12:00Z on 2018-05-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 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
1837 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
243 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
May 2, 3:56 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 33 more9 hr
May 2, 5:29 PM CDTMesoscale DiscussionSPCCook91 min
May 1, 7:24 PM CDTMesoscale DiscussionSPCAdams, Cass, Fremont, Harrison, Mills, Montgomery and 4 more2 hr
May 1, 7:55 PM CDTMesoscale DiscussionSPCAdair, Allamakee, Audubon, Benton, Black Hawk, Boone and 48 more95 min
May 1, 9:38 PM CDTMesoscale DiscussionSPCAdair, Audubon, Benton, Black Hawk, Boone, Bremer and 29 more67 min
May 2, 5:08 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Clarke, Davis, Decatur and 15 more97 min
May 2, 5:27 PM CDTTornado WatchSPCAdams, Appanoose, Clarke, Davis, Decatur, Lucas and 9 more8 hr

Nearby

Mesoscale Discussions in Illinois, 2018Mesoscale Discussions in Iowa, 2018Mesoscale Discussions in Missouri, 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.