Storm Prediction Center Mesoscale Discussion 2250

   Mesoscale Discussion 2250
   NWS Storm Prediction Center Norman OK
   1225 PM CST Sat Dec 06 2025

   Areas affected...Far southeast South Dakota and northwestern Iowa

   Concerning...Heavy snow 

   Valid 061825Z - 070030Z

   SUMMARY...Periods of heavy snowfall are developing across portions
   of far southeastern SD, and will continue to expand into
   northwestern IA within an hour or two. Snowfall rates of 1 to 1.5"
   per hour can be expected.

   DISCUSSION...An area of moderate to heavy snow is expected to
   broaden this afternoon through this evening across northwestern IA,
   as a mid-level shortwave trough approaches. Increasing DPVA will
   accompany this feature, in addition to strong isentropic ascent.
   Most NWP models and forecast soundings suggest omega will peak
   within the dendritic growth zone through ~22Z over northwestern IA.
   HREF probabilities of QPF greater than 0.10" per hour, combined with
   snow to liquid ratios around 15-20 to 1, also support this time
   frame for the heaviest snowfall.

   ..Barnes.. 12/06/2025

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

   ATTN...WFO...DMX...FSD...OAX...

   LAT...LON   43709693 43699633 43629615 43589590 43509545 43439511
               43249476 43069448 42829426 42399452 42339494 42149520
               42109535 42119548 42159557 42189572 42229581 42269592
               42269606 42339633 42429642 42559654 42699686 42849722
               42999725 43449725 43709693