Mesoscale Discussion 1606
   NWS Storm Prediction Center Norman OK
   0128 AM CDT Fri Aug 28 2020

   Areas affected...southern MN and far northern IA

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 280628Z - 280800Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Damaging winds are expected to continue for several hours
   early this morning as storms track eastward across southern MN. A
   severe thunderstorm watch will be issued soon for portions of the
   MCD area.

   DISCUSSION...A severe MCS is tracking eastward across eastern SD at
   around 45-50 kt as of 1 am CDT. Several measured severe gusts
   greater than 75 mph have been recorded over the past few hours. The
   most recent significant severe gust was measured at he Huron SD ASOS
   at 84 mph. 

   Downstream, surface dewpoints in the upper 60s to near 70 F are
   present across southern MN, decreasing to the low-to-mid 60s F
   northward toward central MN. 00z RAOBs from MPX and ABR indicate
   modest midlevel lapse rates atop the moist boundary layer, with some
   dry air noted in the 850-700 mb layer, giving thermodynamic profiles
   typically seen with intense damaging-wind potential. While low-level
   flow is not particularly strong, a 20-30 kt south/southwesterly 850
   mb low level jet is noted in mesoanalysis and regional VWP data.
   Furthermore, strong effective shear will aid in maintaining MCS
   organization as the system tracks eastward along an instability
   gradient across southern MN. 

   With the expectation that severe gusts, some possibly greater than
   64 kt, will continue into southern MN for the next several hours, a
   downstream severe thunderstorm watch will be needed soon as
   convection is expected to move across the SD border into MN by
   around 730z.

   ..Leitman/Edwards.. 08/28/2020

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

   ATTN...WFO...ARX...MPX...DMX...FSD...ABR...

   LAT...LON   43189606 43569665 44679672 45459657 45589606 45189398
               44939314 44749280 44369282 43869304 43389355 43199445
               43189606