Storm Prediction Center Mesoscale Discussion 133

   Mesoscale Discussion 0133
   NWS Storm Prediction Center Norman OK
   1025 AM CST Tue Mar 04 2025

   Areas affected...Eastern South Dakota into far southwestern
   Minnesota and far northern Nebraska

   Concerning...Heavy snow 

   Valid 041625Z - 042030Z

   SUMMARY...Localized moderate to heavy snowfall rates on the order of
   1-2 inches/hour will be possible as snow bands develop across
   eastern South Dakota into far western Minnesota and far northern
   Nebraska.

   DISCUSSION...Transient snow banding has been observed across eastern
   SD into northern NE over the past couple of hours with surface
   observations and web cams under these bands showing localized areas
   of visibility reductions down to 1/4 to 1/2 mile. These bands are
   largely being driven by focused ascent within a 700 mb deformation
   zone augmented by modest warm advection/frontogenesis through the
   850-700 mb layer. Additionally, steep lapse rates within this zone
   are supporting localized areas of convectively-augmented
   precipitation rates (as evidenced by recent lightning strikes over
   the SD/NE/IA border). This deformation zone will continue to be a
   preferential area of transient precipitation band development
   through the late morning and early afternoon hours. Areas to the
   north/northwest of the surface freezing line may experience periods
   of moderate to heavy snowfall rates (1-2 inches/hour) as transient
   snow bands emerge. Given surface gradient winds sustained at 20-25
   mph (gusting to 30-40 mph at times), localized areas of whiteout
   conditions (visibility below 1/4 mile) appear possible under more
   organized bands.

   ..Moore.. 03/04/2025

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

   ATTN...WFO...MPX...FGF...FSD...ABR...LBF...UNR...

   LAT...LON   44529661 43949746 43539787 43049832 42509879 42229916
               42159944 42129978 42260007 42520015 42810014 44979804
               45249776 45479742 45689693 45789655 45809614 45739572
               45589560 45419567 45309580 45109603 44929625 44529661