ZCZC SPCSWOMCD ALL
ACUS11 KWNS 090250 
SPC MCD 090250 
SDZ000-090415-

Mesoscale Discussion 0893
NWS Storm Prediction Center Norman OK
0950 PM CDT Tue Jun 08 2021

Areas affected...Western South Dakota

Concerning...Severe Thunderstorm Watch 249...

Valid 090250Z - 090415Z

The severe weather threat for Severe Thunderstorm Watch 249
continues.

SUMMARY...Severe threat will spread from west to east across ww249.

DISCUSSION...Large-scale forcing for ascent appears to influencing
Black Hills convection this evening. Over the last hour or so, a
squall line has emerged along the leading edge of forcing ahead of
the MT/WY short-wave trough. This activity is spreading east at
roughly 25kt and should approach the eastern edge of ww249 around
05z. While the squall line is the primary convection of concern, an
outflow boundary continues to sag southwest toward this approaching
squall line. This boundary may serve as the focus for new
development, both along and north of the wind shift. Primary severe
risk continues to be hail, though damaging wind threat may increase
just east of the Black Hills if this portion of the squall line
begins to surge along the aforementioned outflow boundary.

..Darrow.. 06/09/2021

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

ATTN...WFO...ABR...UNR...

LAT...LON   43540404 45910403 45910195 43540204 43540404 

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