Alert archive / Missouri / Mesoscale Discussions in 2023

Mesoscale Discussion 1613

July 18, 2023Alexander County, Jackson County, Illinois; 16 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2023, 10:42 AM CDT for Alexander County, Jackson County, Illinois; 16 counties in Missouri. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Jul 18, 2023, 10:42 AM CDT (15:42 UTC)
Expired: Jul 18, 2023, 12:15 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 510

Counties Alexander County, IL, Jackson County, IL, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Carter County, MO, Iron County, MO, Madison County, MO, Mississippi County, MO, Perry County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Scott County, MO, Shannon County, MO, Stoddard County, MO, Washington County, MO, Wayne County, MO

The radar

The St Louis radar (KLSX), 133 km from the middle of the area, began a volume at 15:42 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

Springfield, MO (KSGF), launched 12:00Z, 3.7 hours before the alert went out and 308 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: 2565 J/kg
Mixed-layer CIN: -121 J/kg
Mixed-layer LCL: 1329 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 239 m²/s²
0-3 km storm-relative helicity: 275 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 21.4

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
Jul 18, 8:42 AM CDT	Mesoscale Discussion	SPC	Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 12 more	93 min
Jul 18, 8:59 AM CDT	Severe Thunderstorm Watch	SPC	Alexander, Franklin, Gallatin, Hardin, Jackson, Johnson and 9 more	8 hr
Jul 18, 12:23 PM CDT	Mesoscale Discussion	SPC	Alexander, Franklin, Gallatin, Hardin, Jackson, Johnson and 6 more	97 min
Jul 17, 8:40 PM CDT	Mesoscale Discussion	SPC	Barry, Benton, Camden, Cedar, Christian, Dade and 18 more	95 min

Nearby

Mesoscale Discussions in Missouri, 2023 Mesoscale Discussions in Illinois, 2023 Every mesoscale discussion in 2023

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.