Mesoscale Discussion 1778
   NWS Storm Prediction Center Norman OK
   0919 AM CST Tue Nov 10 2020

   Areas affected...parts of north-central IA...southern MN...northwest
   WI

   Concerning...Freezing rain 

   Valid 101519Z - 102015Z

   SUMMARY...Freezing rain rates exceeding 0.05 inch per 3 hours are
   expected to shift northeast from near the IA/MN border this morning
   and eventually into parts of northwest WI by early afternoon.

   DISCUSSION...Radar mosaic this morning shows a precipitation shield
   moving northeastward from north-central IA into southern MN.  A
   surface cold front is displaced several hundred miles to the
   southeast of this region.  Temperatures this morning are
   sub-freezing and generally in the 30-32 deg F range from northern IA
   northeastward into northwest WI.

   Water-vapor imagery shows a powerful mid-level shortwave trough over
   the central Great Plains and this disturbance is forecast to move
   into western IA by the early to mid afternoon.  Concurrently,
   strengthening frontogenetic forcing at 850 mb will overspread
   southern MN through the remainder of the morning and into northwest
   WI during the 12pm-3pm CST period.  As the column saturates over
   southern MN into northwest WI, a warm layer at or above freezing
   between 900-700 mb is forecast above a shallow sub-freezing layer
   near the surface.  As a result, freezing rain will be the preferred
   precipitation type in a several county-wide corridor from
   south-central MN into northwest WI over the next 5 hours.

   ..Smith.. 11/10/2020

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

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

   LAT...LON   43299363 43389494 46209133 45929018 43299363