Mesoscale Discussion 1864
   NWS Storm Prediction Center Norman OK
   0938 AM CST Wed Dec 23 2020

   Areas affected...Mid-MO Valley to central MN

   Concerning...Blizzard 

   Valid 231538Z - 232045Z

   SUMMARY...Blizzard conditions will spread east across portions of
   the Mid-Missouri Valley north-northeast into southwest and central
   Minnesota through mid-afternoon. Bursts of heavier snow with rates
   of 1-1.5 in/hr is expected just ahead of the blizzard across
   northwest Iowa through central Minnesota.

   DISCUSSION...Widespread blizzard conditions are ongoing across a
   swath of the northern Great Plains to Upper Midwest, centered on
   central/northern NE north-northeast into west-central/northwest MN.
   Numerous observation sites within this corridor have measured 40-55
   kt strong to severe gusts for several hours. As a 990-mb cyclone in
   far north-central IA slowly deepens while tracking towards
   west-central WI, a very tight surface pressure gradient should
   become centered on the Mid-MO Valley to central MN during the 18-21Z
   period amid 60+ kt 850-mb winds. In addition, falling surface
   temperatures will be common through the afternoon with intense cold
   air advection. 

   A swath of probable moderate to heavy snow will persist just ahead
   and accompany the leading plume of blizzard conditions, likely
   becoming centered on the Spencer, IA to Saint Cloud, MN corridor by
   20-21Z. Steep mid-level lapse rates (around 8 C/km from 700-500 mb)
   along the northern periphery of an elevated mixed layer, as sampled
   by 12Z regional soundings will support embedded convective bursts of
   heavier snow around 1-1.5 in/hr.

   ..Grams.. 12/23/2020

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

   ATTN...WFO...DLH...MPX...DMX...FGF...FSD...OAX...ABR...

   LAT...LON   45679586 46409528 46759498 46819400 46499366 46169366
               45549369 44279419 43129474 42569532 42329603 42329665
               42529713 43209725 44779632 45679586