SPC MD 1647

MD 1647 CONCERNING SEVERE THUNDERSTORM WATCH 475...476... FOR EASTERN SOUTH DAKOTA...CENTRAL NEBRASKA

Mesoscale Discussion 1647
NWS Storm Prediction Center Norman OK
0800 PM CDT Sun Aug 30 2020

Areas affected...eastern South Dakota...central Nebraska

Concerning...Severe Thunderstorm Watch 475...476...

Valid 310100Z - 310300Z

The severe weather threat for Severe Thunderstorm Watch 475, 476
continues.

SUMMARY...The severe risk will continue to spread southeastward
across WW 475 and 476. Large hail appears to be the main threat,
with localized wind damage or a brief/weak tornado possible.

DISCUSSION...Rapid storm development occurred along the cold front
late this afternoon with very strong low-level convergence. Storms
briefly thrived within the narrow instability plume across northeast
SD, but have gradually translated southward with time into the
warmer/more unstable air mass. 

The most probable area for a prolonged severe risk appears to be
over central NE where a wider warm sector/uncapped air mass exists.
Damaging hail should remain the primary threat. Increasing capping
will limit eastward extent. 

Farther north, the low-level jet will also maintain favorable lift
over SD this evening, which may allow for a gradual eastward shift
of the severe threat area. Surface-based storms will persist for a
time over southeast SD, but eventually should become elevated with
hail threat as they move east of the instability axis.

..Jewell.. 08/31/2020

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

ATTN...WFO...MPX...FGF...FSD...OAX...ABR...GID...LBF...GLD...

LAT...LON   40359830 40360061 41960019 42509947 44249905 44929882
            44989847 45299793 45769768 46369729 46359591 42949738
            42959748 40359830 40340059 40359830 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1647.html