Alert archive / Missouri / Mesoscale Discussions in 2018

Mesoscale Discussion 460

May 19, 20184 states

The Storm Prediction Center issued this mesoscale discussion at May 19, 2018, 11:56 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 19, 2018, 11:56 AM CDT (16:56 UTC)
Expired: May 19, 2018, 2:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 24 counties

Clay County, AR, Fulton County, KY, Hickman County, KY, Butler County, MO, Carter County, MO, Dent County, MO, Douglas County, MO, Howell County, MO, Laclede County, MO, Mississippi County, MO, New Madrid County, MO, Oregon County, MO, Pemiscot County, MO, Reynolds County, MO, Ripley County, MO, Shannon County, MO, Stoddard County, MO, Texas County, MO, Wayne County, MO, Webster County, MO, Wright County, MO, Dyer County, TN, Lake County, TN, Obion County, TN

The radar

The Memphis radar (KNQA), 197 km from the middle of the area, began a volume at 16:58 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.

Severe Thunderstorm Watch 107May 19, 1:35 PM CDT

The nearest sounding before it

Little Rock, AR (KBYH), launched 12:00Z, 4.9 hours before the alert went out and 245 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: 1509 J/kg
Mixed-layer CIN: -112 J/kg
Mixed-layer LCL: 1149 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 7 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.6

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 19, 1:36 PM CDT	Severe Thunderstorm Watch	SPC	Clay, Greene, Mississippi, Randolph	6 hr
May 19, 3:35 PM CDT	Mesoscale Discussion	SPC	Clay, Greene, Randolph	85 min
May 19, 6:14 PM CDT	Mesoscale Discussion	SPC	Clay, Craighead, Greene, Mississippi, Randolph	61 min
May 19, 7:50 AM CDT	Mesoscale Discussion	SPC	Barton, Bates, Benton, Camden, Cass, Cedar and 22 more	115 min
May 19, 1:42 PM CDT	Mesoscale Discussion	SPC	Andrew, Atchison, Buchanan, Clay, Clinton, DeKalb and 3 more	3 hr
May 19, 2:30 PM CDT	Severe Thunderstorm Watch	SPC	Barton, Benton, Camden, Cedar, Dade, Dallas and 8 more	11 hr
May 19, 4:21 PM CDT	Severe Thunderstorm Watch	SPC	Bates, Buchanan, Caldwell, Carroll, Cass, Chariton and 12 more	3 hr
May 19, 6:11 PM CDT	Mesoscale Discussion	SPC	Barry, Barton, Camden, Cedar, Christian, Dade and 20 more	2 hr

Nearby

Mesoscale Discussions in Missouri, 2018 Mesoscale Discussions in Tennessee, 2018 Mesoscale Discussions in Kentucky, 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.