Alert archive / Missouri / Mesoscale Discussions in 2019

Mesoscale Discussion 384

April 18, 201921 counties in Illinois; 23 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2019, 2:16 AM CDT for 21 counties in Illinois; 23 counties in Missouri. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Apr 18, 2019, 2:16 AM CDT (07:16 UTC)
Expired: Apr 18, 2019, 4:15 AM CDT
In force: 119 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 44 counties

Bond County, IL, Calhoun County, IL, Christian County, IL, Clay County, IL, Clinton County, IL, Cumberland County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Jefferson County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Shelby County, IL, Washington County, IL, Callaway County, MO, City of Saint Louis, MO, Cole County, MO, Crawford County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Maries County, MO, Miller County, MO, Montgomery County, MO, Osage County, MO, Phelps County, MO, Pulaski County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Texas County, MO, Warren County, MO, Washington County, MO, Wright County, MO

The radar

The St Louis radar (KLSX), 23 km from the middle of the area, began a volume at 07:18 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

Lincoln, IL (KILX), launched 00:00Z, 7.3 hours before the alert went out and 263 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: 39 J/kg
Mixed-layer CIN: -375 J/kg
Mixed-layer LCL: 1740 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 209 m²/s²
0-3 km storm-relative helicity: 300 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
Apr 17, 7:49 PM CDT	Mesoscale Discussion	SPC	Bates	86 min
Apr 17, 9:52 PM CDT	Mesoscale Discussion	SPC	Barton, Jasper, Newton, Vernon	83 min
Apr 17, 11:07 PM CDT	Mesoscale Discussion	SPC	Barton, Bates, Benton, Camden, Cedar, Dade and 13 more	83 min
Apr 17, 11:23 PM CDT	Severe Thunderstorm Watch	SPC	Barton, Bates, Benton, Camden, Cedar, Dade and 15 more	3 hr
Apr 18, 1:15 AM CDT	Mesoscale Discussion	SPC	Bollinger, Butler, Carter, Dunklin, Howell, Iron and 11 more	60 min

Nearby

Mesoscale Discussions in Missouri, 2019 Mesoscale Discussions in Illinois, 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.