Mesoscale Discussion 1238

Issued

Jul 10, 2021, 1:25 PM CDT (18:25 UTC)

Expired

Jul 10, 2021, 3:30 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch likely

Chance of a watch

80%

The St Louis radar (KLSX), 127 km from the middle of the area, began a volume at 18:26 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.

• Severe Thunderstorm Watch 365Jul 10, 2:00 PM CDT
• Severe Thunderstorm Watch 367Jul 10, 3:00 PM CDT

014 
ACUS11 KWNS 101825
SWOMCD
SPC MCD 101825 
INZ000-KYZ000-ILZ000-MOZ000-102030-

Mesoscale Discussion 1238
NWS Storm Prediction Center Norman OK
0125 PM CDT Sat Jul 10 2021

Areas affected...southern Missouri...southern Illinois...and western
Kentucky

Concerning...Severe potential...Watch likely 

Valid 101825Z - 102030Z

Probability of Watch Issuance...80 percent

SUMMARY...Multiple clusters of thunderstorms are expected to develop
through the mid afternoon. Large hail and damaging thunderstorm
winds will be the primary threat, although a tornado or two cannot
be ruled out.

DISCUSSION...A large precipitation shield continues to wane in
coverage early this afternoon across south-central Missouri.
Furthermore, the associated cloud cover continues to thin -- with
breaks in the coverage identified across southeast Missouri. These
breaks in the cloud cover have allowed surface temperatures to warm
into the upper 80s F in the presence of surface dewpoints in the
low-to-mid 70s F, yielding surface-based CAPE between 2000-3000
J/kg. As temperatures warm and surface inhibition diminishes,
multiple clusters of thunderstorms are expected to develop along and
south of a front stretching from central Kansas east into central
Illinois. Although the better deep-layer shear is confined to Kansas
and southwest Missouri, it should be sufficiently strong along and
near the front to support updraft organization, with large hail and
damaging thunderstorm winds possible. With time merging thunderstorm
cold pools and outflows should result in upscale growth into one or
more MCSs that move south, posing a more widespread damaging wind
threat. Before the eventual upscale growth, a tornado or two cannot
be ruled out with discrete cells interacting with with front or
other outflow boundaries.

Given the likelihood of multiple clusters of severe thunderstorms
this afternoon, one or more watches will likely be needed across the
area.

..Marsh/Bunting.. 07/10/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LMK...IND...PAH...ILX...LSX...SGF...

LAT...LON   36679313 36739406 37269439 37869395 38229163 38628993
            38888825 38768736 38128700 37148751 36668870 36658978
            36679313

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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.