Alert archive / Illinois / Mesoscale Discussions in 2019

Mesoscale Discussion 677

May 18, 20197 counties in Illinois; Des Moines County, Lee County, Van Buren County, Iowa; 5 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 18, 2019, 6:59 PM CDT for 7 counties in Illinois; Des Moines County, Lee County, Van Buren County, Iowa; 5 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 18, 2019, 6:59 PM CDT (23:59 UTC)
Expired: May 18, 2019, 9:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Des Moines County, IA, Lee County, IA, Van Buren County, IA, Adams County, IL, Brown County, IL, Hancock County, IL, Henderson County, IL, McDonough County, IL, Schuyler County, IL, Warren County, IL, Clark County, MO, Knox County, MO, Lewis County, MO, Marion County, MO, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 151 km from the middle of the area, began a volume at 00:01 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, 12.0 hours before the alert went out and 156 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: 1345 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 181 m²/s²
0-3 km storm-relative helicity: 177 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.

Issued	Product	Office	Counties	Lasted
May 18, 4:40 PM CDT	Severe Thunderstorm Watch	SPC	Calhoun, Jersey, Madison, Monroe, Randolph, Saint Clair	4 hr
May 18, 9:38 AM CDT	Mesoscale Discussion	SPC	Barry, Barton, Cedar, Dade, Greene, Jasper and 6 more	2 hr
May 18, 10:07 AM CDT	Tornado Watch	SPC	Barry, Barton, Bates, Benton, Camden, Cedar and 22 more	7 hr
May 18, 12:47 PM CDT	Mesoscale Discussion	SPC	Barry, Barton, Bates, Benton, Camden, Cedar and 27 more	88 min
May 18, 3:32 PM CDT	Mesoscale Discussion	SPC	Callaway, Camden, Carter, Christian, Cole, Crawford and 23 more	88 min
May 18, 6:19 PM CDT	Mesoscale Discussion	SPC	Dunklin, Pemiscot	116 min

Nearby

Mesoscale Discussions in Illinois, 2019 Mesoscale Discussions in Missouri, 2019 Mesoscale Discussions in Iowa, 2019 Every mesoscale discussion in 2019

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.