Mesoscale Discussion 0055
   NWS Storm Prediction Center Norman OK
   1024 AM CST Fri Jan 12 2024

   Areas affected...Eastern Iowa into northern Illinois and southern
   Wisconsin

   Concerning...Heavy snow 

   Valid 121624Z - 122030Z

   SUMMARY...Areas of 1+ in/hour snowfall rates appear probable within
   a broader swath of moderate snowfall across eastern Iowa into
   southern Wisconsin and northern Illinois through early afternoon.

   DISCUSSION...Surface observations over the past couple of hours have
   been reporting visibilities between 1/4 to 1/2 mile from eastern IA
   into southern WI and far northern IL. Sustained 20-25 knot winds
   across eastern IA are supporting areas of blowing snow per blowing
   snow model output and web cams, which is contributing to the reduced
   visibilities. Further east into WI/IL, weaker winds suggest moderate
   to heavy snowfall rates are the primary contributors to the reduced
   visibility. Regional radar mosaics support this idea with relatively
   short (~1 hour) snow bands noted over the past hour. These bands
   appear to be mainly driven by strong warm air advection within the
   0-2 km layer based on regional VWP observations. Despite the
   magnitude of the warm air advection, 12 UTC and recent RAP forecast
   soundings suggest this ascent is displaced from the DGZ within the
   3-4 km layer. This will modulate snowfall rates across the broader
   region, but heavier snowfall rates at/above 1 in/hour will be
   possible within the transient snow bands. This trend should continue
   through early/mid afternoon before stronger ascent within the warm
   advection regime shifts northeast with the synoptic low.

   ..Moore.. 01/12/2024

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

   ATTN...WFO...GRB...LOT...MKX...DVN...ARX...DMX...

   LAT...LON   42298784 42288865 42098933 41709012 41229071 40879134
               40829179 40969224 41859276 42199268 42539238 43209128
               44258906 44358860 44458819 44478769 44388732 43928757
               43318770 42818768 42488762 42298784