Mesoscale Discussion 1865
   NWS Storm Prediction Center Norman OK
   1233 PM CST Wed Dec 23 2020

   Areas affected...North-central IA...south-central to eastern
   MN...and northwest WI

   Concerning...Blizzard 

   Valid 231833Z - 232230Z

   SUMMARY...Moderate to heavy snow will overspread the I-35 corridor,
   with blizzard conditions also expected to spread east across at
   least north-central IA and south-central MN into a portion of
   east-central MN.

   DISCUSSION...Convective showers have developed as-advertised across
   the Twin Cities Metro Area within an area of strongly forced ascent
   just north of the 989-mb surface cyclone in southeast MN. Intense
   surface cold advection which has resulted in falling daytime
   temperatures over central MN will spread east and result in rain
   transitioning to snow as the cyclone tracks into north-central WI.
   The combination of this convective development merging into the
   broader snow band within the cold conveyor region may yield an
   uptick in heavy snow intensity through mid-afternoon, particularly
   across east-central MN into northwest WI. Snowfall rates of 1-1.5
   in/hr should be common but may briefly peak around 2 in/hr before
   beginning to taper off in the late afternoon to early evening. 

   Blizzard conditions will also become widespread across south-central
   MN and north-central IA in conjunction with the southern extent of
   at least moderate snow and overspreading of 60+ kt 850-mb
   northwesterlies. This belt of very strong flow will weaken this
   evening as the cyclone begins to slowly fill. This should result in
   shorter-duration and more localized blizzard conditions farther
   east/north in far eastern MN into western WI.

   ..Grams.. 12/23/2020

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

   ATTN...WFO...DLH...ARX...MPX...DMX...FSD...

   LAT...LON   43099290 42319405 42209513 42479534 43259460 45359374
               46549352 47489254 47859185 47919101 47829060 47089103
               45679187 44269235 43099290