ACUS11 KWNS 091901
SWOMCD
SPC MCD 091901
SDZ000-092030-

Mesoscale Discussion 1556
NWS Storm Prediction Center Norman OK
0201 PM CDT Thu Jul 09 2026

Areas affected...portions of the Black Hills and southwestern South
Dakota

Concerning...Severe potential...Watch unlikely

Valid 091901Z - 092030Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated thunderstorms may move off the Black Hills in
southwestern South Dakota and promote an isolated severe threat this
afternoon. A further increase in strong to severe thunderstorm
potential is expected late this afternoon and into the evening.

DISCUSSION...An isolated thunderstorm has recently developed across
the Black Hills in southwestern South Dakota. While latest objective
analysis suggests that capping remains in place to the east of the
Black Hills, modifying the nearby UNR 18z observed sounding for
current surface observations suggests that inhibition is quickly
eroding amid continued insolation. This may allow isolated
convection to evolve eastward off of the Black Hills this afternoon.
Should this scenario occur, storms would encounter increasing
instability across central South Dakota, with modest effective shear
(25-30 kts), well-mixed boundary layer profiles, and steep mid-level
lapse rates (as sampled by the aforementioned UNR observed sounding)
promoting a risk for isolated damaging/severe wind gusts and large
hail. Given that this risk remains conditional on a storm persisting
eastward off of the Black Hills, watch issuance is uncertain at this
time. An increase in severe potential and convective coverage is
then expected later this evening across portions of western South
Dakota.

..Chalmers/Hart.. 07/09/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!4lADqwGc9CUOlIX-x6Hb1TPwILkb5CZ2GF0HJauSl5YYlDPLOt_-2pjGOBNMDCfzMvZ3MhywnSv1Caow_GX-XQUR54A$ for graphic product...

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

LAT...LON 43410276 43380317 43430356 43580388 43830402 44130404
44500399 44700393 44790377 44790318 44750266 44550228
44200203 43840207 43580234 43410276

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


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--- scorpsmtpd
* Origin: Capitol City Online (1:2320/107)