South Dakota Mesoscale Discussion

Areas affected…Portions of eastern NE…western/central
IA…central/eastern SD…and southwestern MN

Concerning…Heavy snow

Valid 171232Z – 171800Z

SUMMARY…Moderate to heavy snowfall, with rates around 1 inch per
hour, will develop and then spread northeastward this morning.

DISCUSSION…Within large-scale upper troughing over much of the
western/central CONUS, a lead shortwave trough will continue to
eject northeastward this morning across the central Plains and
towards the Upper Midwest. The 12Z sounding from Omaha NE shows
strong southerly winds in the 925-700-mb layer. This low-level warm
advection and additional large-scale ascent preceding the shortwave
trough are promoting a broad area of precipitation this morning
across parts of the southern/central Plains. From roughly the NE/KS
border northward, the low-level thermodynamic profile should remain
cold enough to support snow as the dominant precipitation type.
Strong lift is forecast to occur through 18Z in the dendritic growth
zone from eastern NE into parts of western/central IA,
central/eastern SD, and southwestern MN. Light to locally moderate
snow ongoing across central/eastern NE and vicinity is likewise
expected to increase in intensity through the remainder of this
morning as this broad area of snow shifts northeastward. Snowfall
rates around 1 inch per hour appear likely by 15Z over parts of this
region, with locally higher rates possible through 18Z within the
most intense portion of the snow band.

..Gleason.. 01/17/2020

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

ATTN…WFO…MPX…DMX…FSD…OAX…ABR…GID…LBF…

LAT…LON 43029367 41939304 41329266 40919287 40719342 40659445
40599578 40639680 41019737 41549798 42079861 42539919
42989948 43759950 44679863 45509701 45559549 44889450
44019380 43029367

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