ZCZC SPCSWOMCD ALL
ACUS11 KWNS 221921 
SPC MCD 221921 
SDZ000-NDZ000-222145-

Mesoscale Discussion 1576
NWS Storm Prediction Center Norman OK
0221 PM CDT Sun Aug 22 2021

Areas affected...the east-central Dakotas

Concerning...Severe potential...Watch likely 

Valid 221921Z - 222145Z

Probability of Watch Issuance...80 percent

SUMMARY...Storms will likely form by 21Z, with severe hail or a
tornado possible as they mature across the Dakotas.

DISCUSSION...Surface analysis shows a low over north-central ND,
with a developing cold front extending south/southwestward into
western SD, and a dryline from near BIS to PIR. A diffuse warm front
extends east from the low across ND, where pockets of heating and
low-level warm advection are helping to slowly destabilize the air
mass.

Moisture quality is a concern across the region, but cooling aloft
as well as strong lift along the front will likely result in a few
severe storms after 20-21Z. Wind profiles are favorable or
supercells with deep-layer shear around 50 kt and increasing SRH.
Given drying behind the cold front, and relatively coolness
currently over the eastern Dakotas, only a narrow ribbon of
surface-based/effective SRH is expected to exist immediately ahead
of the front. Tornado potential is heavily dependent on
boundary-layer moisture quality, but the overall supercell setup
appears favorable. As such, a watch will likely be needed. Large
hail will be a distinct threat given expected storm mode as well as
cool temperatures aloft.

..Jewell/Kerr.. 08/22/2021

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

ATTN...WFO...FGF...FSD...ABR...BIS...

LAT...LON   44579784 44349804 43929866 43879940 44099996 45680020
            46480036 47330073 47940091 48310090 48600020 48169884
            47579829 46359794 45529781 44579784 

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