Alert archive / Missouri / Mesoscale Discussions in 2018

Mesoscale Discussion 478

May 20, 2018Benton County, Carroll County, Arkansas; 36 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 20, 2018, 6:25 PM CDT for Benton County, Carroll County, Arkansas; 36 counties in Missouri. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
May 20, 2018, 6:25 PM CDT (23:25 UTC)
Expired
May 20, 2018, 8:00 PM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 38 counties

Benton County, AR, Carroll County, AR, Barry County, MO, Barton County, MO, Bates County, MO, Benton County, MO, Camden County, MO, Cedar County, MO, Christian County, MO, Cole County, MO, Crawford County, MO, Dade County, MO, Dallas County, MO, Dent County, MO, Douglas County, MO, Greene County, MO, Henry County, MO, Hickory County, MO, Jasper County, MO, Laclede County, MO, Lawrence County, MO, Maries County, MO, McDonald County, MO, Miller County, MO, Moniteau County, MO, Morgan County, MO, Newton County, MO, Osage County, MO, Phelps County, MO, Polk County, MO, Pulaski County, MO, St. Clair County, MO, Stone County, MO, Taney County, MO, Texas County, MO, Vernon County, MO, Webster County, MO, Wright County, MO

The radar

The Springfield radar (KSGF), 25 km from the middle of the area, began a volume at 23:25 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, 11.4 hours before the alert went out and 76 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, Springfield, MO at 12:00Z on 2018-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1422 joules per kilogram.LCLLFCEL10008507005003002001001 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, Springfield, MO at 12:00Z on 2018-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 159 square meters per square second.193958Sfc1 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
1422 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
1014 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
159 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.6
Supercell composite
5.3

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 20, 1:11 AM CDTMesoscale DiscussionSPCPolk, Scott, Sebastian2 hr
May 20, 11:43 AM CDTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Greene, Independence and 11 more3 hr
May 20, 12:32 PM CDTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lawrence and 6 more6 hr
May 20, 3:32 PM CDTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Greene, Lee and 4 more118 min
May 20, 3:32 PM CDTSevere Thunderstorm WatchSPCBenton4 hr
May 20, 6:26 PM CDTMesoscale DiscussionSPCArkansas, Craighead, Crittenden, Cross, Greene, Jackson and 8 more64 min
May 19, 7:41 PM CDTMesoscale DiscussionSPCBates, Benton, Cass, Henry, Johnson, Pettis94 min
May 20, 12:42 AM CDTMesoscale DiscussionSPCBarton, Bates, Benton, Camden, Cass, Cedar and 28 more3 hr
May 20, 2:24 PM CDTMesoscale DiscussionSPCBarry, Barton, Bates, Benton, Camden, Cedar and 16 more3 hr

Nearby

Mesoscale Discussions in Missouri, 2018Mesoscale Discussions in Arkansas, 2018Every 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.