Alert archive / Illinois / Mesoscale Discussions in 2018

Mesoscale Discussion 406

May 14, 20185 states

The Storm Prediction Center issued this mesoscale discussion at May 14, 2018, 2:40 AM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 14, 2018, 2:40 AM CDT (07:40 UTC)
Expired: May 14, 2018, 4:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 34 counties

Dubuque County, IA, Jackson County, IA, Boone County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Jo Daviess County, IL, Kane County, IL, Lake County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Winnebago County, IL, Elkhart County, IN, LaGrange County, IN, LaPorte County, IN, Noble County, IN, Saint Joseph County, IN, Allegan County, MI, Berrien County, MI, Cass County, MI, Saint Joseph County, MI, Van Buren County, MI, Dane County, WI, Green County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 76 km from the middle of the area, began a volume at 07:42 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 00:00Z, 7.7 hours before the alert went out and 153 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1260 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 241 m²/s²
0-3 km storm-relative helicity: 314 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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.

Issued	Product	Office	Counties	Lasted
May 14, 2:37 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Bureau, Cass, Champaign, DeWitt and 32 more	53 min
May 14, 2:54 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Bond, Boone, Brown, Bureau, Calhoun and 59 more	6 hr
May 14, 6:36 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Cass, Champaign, Christian, Clinton and 36 more	84 min

Nearby

Mesoscale Discussions in Illinois, 2018 Mesoscale Discussions in Wisconsin, 2018 Mesoscale Discussions in Indiana, 2018 Every 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.