ZCZC SPCSWOMCD ALL
ACUS11 KWNS 272333 
SPC MCD 272333 
SDZ000-280130-

Mesoscale Discussion 1622
NWS Storm Prediction Center Norman OK
0633 PM CDT Fri Aug 27 2021

Areas affected...Northwestern South Dakota

Concerning...Severe potential...Watch unlikely 

Valid 272333Z - 280130Z

Probability of Watch Issuance...20 percent

SUMMARY...Large to very large-hail will be possible with a supercell
in northwest South Dakota. Damaging wind gusts are also possible.
Activity may persist for another 1-3 hours. A watch is not expected
unless storm coverage becomes greater than anticipated.

DISCUSSION...A supercell thunderstorm has intensified over the past
hour or so. GOES mesosector imagery has shown the development of a
back-sheared anvil and a more pronounced overshooting top. MRMS
CAPPI data have also indicated very high reflectivity aloft. With
over 50 kts of effective shear and the storm moving into a better
thermodynamic environment to the east, large to very large (2+ inch)
hail and damaging wind gusts will be threats. Storm coverage
continues to be the main question. Dry surface conditions have
limited buoyancy despite the mid-level ascent with a broad trough to
the northwest. Activity may persist a few hours into the evening
with support from an increasing low-level jet into central South
Dakota. A watch is not expected this evening given the isolated
coverage expected.

..Wendt/Bunting.. 08/27/2021

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

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

LAT...LON   45280401 45720310 45840205 45480149 44920141 44700229
            44820345 44960387 45280401 

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