ZCZC SPCSWOMCD ALL
ACUS11 KWNS 120756 
SPC MCD 120756 
ILZ000-MOZ000-120930-

Mesoscale Discussion 1960
NWS Storm Prediction Center Norman OK
0256 AM CDT Sat Aug 12 2023

Areas affected...Parts of northern/central MO into central/southern
IL

Concerning...Severe Thunderstorm Watch 631...632...

Valid 120756Z - 120930Z

The severe weather threat for Severe Thunderstorm Watch 631, 632
continues.

SUMMARY...The primary damaging-wind threat will spread
east-southeastward overnight.

DISCUSSION...Storm clusters that initially developed across northern
MO have recently shown a tendency for east-southeastward propagation
as convective outflow becomes increasingly dominant. The primary
damaging-wind threat over the next 2-3 hours will likely be
associated with storms that are currently north of the Columbia to
St. Louis corridor, which will move east-southeastward in
conjunction with the expanding outflow. Moderate to strong buoyancy
and effective shear of 35-45 kt will continue to favor organized
convection, though gradually increasing MLCINH may tend to limit the
severe-wind threat to some extent. Relatively steep midlevel lapse
rates will also support an isolated hail threat with the stronger
embedded cells. 

Farther northwest, storms continue to regenerate across northwest
MO, though recent development has tended to be weaker than earlier
storms, and is likely becoming increasingly elevated as outflow
moves well south of the region. Isolated hail cannot be ruled out
with the stronger storms in this area overnight, though a gradual
decrease in the threat is expected to continue. 

Some threat could linger across northern MO past the 09 UTC
expiration time of WW 631, and local extension may be considered
depending on trends regarding storm intensity over the next hour.
However, the primary threat should continue shifting into WW 632
with time.

..Dean.. 08/12/2023

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

ATTN...WFO...PAH...ILX...LSX...EAX...

LAT...LON   40449442 39839266 39729163 39769106 40069074 40129053
            39728901 39308824 38798806 38488823 38288880 38378972
            38469072 38579178 38789244 39359329 40109466 40449442 

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