ZCZC SPCSWOMCD ALL
ACUS11 KWNS 080012 
SPC MCD 080012 
SDZ000-NDZ000-080145-

Mesoscale Discussion 1437
NWS Storm Prediction Center Norman OK
0712 PM CDT Sat Aug 07 2021

Areas affected...Portions of the Dakotas

Concerning...Severe potential...Watch unlikely 

Valid 080012Z - 080145Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated severe storms near an area of low pressure across
the Dakotas may pose a risk for damaging winds and isolated hail
this evening. A non-supercell tornado may also be possible in
vicinity of the surface low. Storm coverage is expected to remain
low suggesting a watch is unlikely.

DISCUSSION...Evening water vapor imagery showed a well defined
shortwave trough moving out of the Rockies and into the central
Plains. Ahead of this wave, an area of low pressure at the surface
was observed near the north Dakota south Dakota Border. Lift from a
cold front extending south from the low has resulted in isolated
storm development along an arcing line from south-central North
Dakota to near Aberdeen, South Dakota. Despite prominent smoke and
haze, daytime heating and dewpoints in the upper 60s F have resulted
in moderate instability (2000-3000 J/kg of MLCAPE). Winds aloft
however are weak, with the Aberdeen VAD indicating effective shear
remains below 30 kts. Severe potential appears modest, but a few
stronger multicell storms may become organized early this evening.
Steep mid-level lapse rates and large buoyancy will support the
potential for severe hail and damaging outflow winds with the
strongest storms. Enhanced stretching from 0-3km CAPE in excess of
100 J/kg east of the low center and locally greater vertical
vorticity beneath the vortmax may also support a non-supercell
tornado this evening. Uncertainty on storm organization remains
high, suggesting that a weather watch is unlikely.

..Lyons/Hart.. 08/08/2021

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

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

LAT...LON   46839944 46909911 46889850 46729801 46469758 45999710
            45489718 45139766 45069844 45289872 45599876 45989900
            46189955 46639977 46839944 

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