ZCZC SPCSWOMCD ALL
ACUS11 KWNS 160348 
SPC MCD 160348 
ILZ000-MOZ000-IAZ000-ARZ000-OKZ000-KSZ000-160515-

Mesoscale Discussion 2039
NWS Storm Prediction Center Norman OK
0948 PM CST Wed Dec 15 2021

Areas affected...portions of far western Illinois...northeast to
southwest Missouri...far northeastern Oklahoma

Concerning...Severe Thunderstorm Watch 566...

Valid 160348Z - 160515Z

The severe weather threat for Severe Thunderstorm Watch 566
continues.

SUMMARY...A few damaging/severe gusts remain possible for a few more
hours with a squall line. Damaging gusts will be more likely across
east-central Missouri into western IL, where synoptic forcing is
greater. A local WW extension may be needed in parts of central IL.

DISCUSSION...A broken squall line continues to produce occasional
damaging or severe gusts despite a gradual decline in intensity
noted over the past couple of hours. Buoyancy is on the wane across
portions of the Mid Mississippi Valley, with synoptic-scale upper
support drifting northeast with the surface low into the Upper
Mississippi Valley. However, intense low-level winds (70+ kt at 1 km
AGL) prevail ahead of the squall line, so any downward momentum
transport in the stronger convective cores can easily support severe
gusts. The severe threat is expected to persist for a few more
hours, especially across eastern MO into central IL, where
relatively stronger forcing for ascent is present. As such, local WW
extension may be needed in parts of central IL should the line hold
together.

..Squitieri/Hart.. 12/16/2021

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

ATTN...WFO...ILX...LSX...DVN...LZK...SGF...EAX...TSA...ICT...

LAT...LON   36239662 37119497 38929224 40859105 41249055 41088980
            40818932 40348911 39438976 38249098 37169217 36259337
            36119405 36019538 36239662 

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