Alert archive / Illinois / Mesoscale Discussions in 2019

Mesoscale Discussion 730

May 21, 201945 counties in Illinois; 16 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 21, 2019, 7:37 PM CDT for 45 counties in Illinois; 16 counties in Missouri. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
May 21, 2019, 7:37 PM CDT (00:37 UTC)
Expired
May 21, 2019, 9:00 PM CDT
In force
83 min
Issued by
the Storm Prediction Center
All 61 counties

Alexander County, IL, Bond County, IL, Calhoun County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Greene County, IL, Hamilton County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Johnson County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Perry County, IL, Pike County, IL, Pulaski County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Union County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Iron County, MO, Jefferson County, MO, Lincoln County, MO, Madison County, MO, Perry County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO

The radar

The St Louis radar (KLSX), 78 km from the middle of the area, began a volume at 00:42 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 0.6 hours before the alert went out and 208 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, Lincoln, IL at 00:00Z on 2019-05-22Temperature 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, Lincoln, IL at 00:00Z on 2019-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 466 square meters per square second.1939587897Sfc1 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
667 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
466 m²/s²
0-3 km storm-relative helicity
506 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

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 21, 8:48 PM CDTTornado WatchSPCAlexander, Clay, Coles, Cumberland, Effingham, Franklin and 11 more3 hr
May 21, 11:26 PM CDTMesoscale DiscussionSPCClark, Crawford, Cumberland, Edwards, Gallatin, Hamilton and 11 more94 min
May 22, 4:00 PM CDTTornado WatchSPCAdams, Brown, Bureau, Cass, Fulton, Hancock and 18 more7 hr
May 22, 5:59 PM CDTMesoscale DiscussionSPCAdams, Brown, Bureau, Calhoun, Cass, Fulton and 20 more2 hr
May 21, 8:46 PM CDTMesoscale DiscussionSPCAtchison, Holt59 min
May 22, 3:06 PM CDTMesoscale DiscussionSPCBarry, Barton, Bates, Benton, Camden, Cass and 16 more114 min
May 22, 3:32 PM CDTTornado Watch PDSSPCBarton, Bates, Benton, Camden, Carroll, Cass and 22 more7 hr
May 22, 5:05 PM CDTMesoscale DiscussionSPCMcDonald, Newton85 min

Nearby

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