South Dakota Mesoscale Discussion

Areas affected…Southwest ND…Western SD

Concerning…Severe potential…Watch possible

Valid 101956Z – 102130Z

Probability of Watch Issuance…40 percent

SUMMARY…Isolated severe thunderstorms capable of large hail and
severe wind will continue into late afternoon. The need for a watch
is uncertain due to the limited areal coverage of the threat.

DISCUSSION…A supercell has recently developed across southwest ND,
with other cells attempting to develop across northeast SD, and
further south over the Black Hills. Ongoing convection is being
aided by moderate buoyancy (MLCAPE of 1000-1500 J/kg) and effective
shear of 35-45 kt, which will continue to support a threat of
isolated supercells posing a risk of large hail, severe wind gusts,
and perhaps a brief tornado.

The airmass downstream of ongoing activity is noticeably cooler and
more stable. Thus, the eastward extent of the threat may be
relatively limited, with cells exhibiting more of a rightward motion
(such as the cell in southwest ND) having more of a residence time
within the generally uncapped and more favorable environment. The
constrained area of the threat may preclude watch issuance, though
at least a couple supercells will be possible into late afternoon
across a portion of the region.

..Dean/Grams.. 08/10/2019

…Please see for graphic product…


LAT…LON 43640369 44580375 45740326 46580260 46800231 46810193
46610161 46290146 45570162 44600197 43610247 43540320

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