South Dakota Mesoscale Discussion

Areas affected…eastern South Dakota and vicinity

Concerning…Severe Thunderstorm Watch 583…

Valid 152242Z – 160045Z

The severe weather threat for Severe Thunderstorm Watch 583

SUMMARY…The severe threat continues across eastern portions of
WW583 in eastern South Dakota and vicinity. Damaging winds and large
hail remain possible through 0200 UTC.

DISCUSSION…A line of thunderstorms continues to move eastward
across eastern South Dakota and recently produced a 66 MPH wind gust
at a mesonet site in Day county. Recent radar trends from KABR show
two areas where the rear inflow has strengthened in Clark and Day
counties and could be foci for severe wind and a possible brief,
weak tornado. Given the storm environment downstream of MLCAPE of
1000-1500 J/kg and effective bulk shear of 40-50 knots, the line of
storms should continue moving eastward and maintain its intensity.
Storm development and intensification on southern portion of the
line may occur, especially since the instability remains favorable
longer, with the hail threat being greater in this area.

Even with the large-scale ascent associated with the shortwave
trough moving over South Dakota, storms will begin to wane in
southwest Minnesota/northwest Iowa without a low-level jet to help
sustain development tonight. Storms may move outside of the watch
later this evening before weakening, but a new watch is unlikely at
this time.

..Nauslar/Guyer.. 08/15/2019

…Please see for graphic product…


LAT…LON 45889738 45059778 44259837 43899836 43509829 43409781
43329684 43469644 43739629 44309615 45209607 45419612
45779634 45979657 45889738

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