ZCZC SPCSWOMCD ALL
ACUS11 KWNS 170016 
SPC MCD 170016 
NEZ000-SDZ000-170145-

Mesoscale Discussion 1301
NWS Storm Prediction Center Norman OK
0716 PM CDT Fri Jul 16 2021

Areas affected...Southwestern SD...Northwestern NE

Concerning...Severe Thunderstorm Watch 381...

Valid 170016Z - 170145Z

The severe weather threat for Severe Thunderstorm Watch 381
continues.

SUMMARY...Severe threat will gradually shift southeast this evening.

DISCUSSION...Scattered convection that initiated over the northern
Black Hills has propagated off the higher terrain and a
well-identifiable outflow boundary has surged ahead of this cluster.
Several storm mergers are now occurring along this boundary over
Oglala Lakota County SD, while new updrafts are developing along the
wind shift between Chadron and Hot Springs. This activity should
continue to grow upscale over the next few hours as it propagates
southeast. With LLJ expected to increase into this region it should
provide some longevity to the expanding complex. Hail and wind
remain possible with this maturing MCS.

..Darrow.. 07/17/2021

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

ATTN...WFO...LBF...UNR...CYS...

LAT...LON   43070395 43420304 44010253 43550137 42690151 42420294
            43070395 

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