Mesoscale Discussion 1487
   NWS Storm Prediction Center Norman OK
   0157 PM CDT Fri Aug 14 2020

   Areas affected...portions of far eastern SD...southwest into central
   MN...northwest IA and far northeast NE

   Concerning...Severe potential...Watch likely 

   Valid 141857Z - 142100Z

   Probability of Watch Issuance...95 percent

   SUMMARY...The severe threat is increasing across the MCD area. One
   or more watches will be needed in the next 1-2 hours.

   DISCUSSION...A surface low is currently located over far northeast
   SD with a cold front trailing south/southwest across far eastern SD
   into northeast and central NE. Deepening CU has been noted in
   visible satellite imagery over the past hour and convective
   initiation appears likely to occur soon near the NE/SD border. Ahead
   of the front, temperatures have warmed into the low to mid 80s F
   with dewpoints generally from the mid 60s to low 70s F. An outflow
   boundary produced by overnight convection resides across central MN.
   While some airmass recovery has been made in the vicinity of the
   boundary, surface dewpoints remain in the lower 60s. Nevertheless,
   moderate to strong instability is present over the region, aided
   further by steep midlevel lapse rates. Temperatures are quickly
   approaching convective temp per modified RAP forecast soundings and
   remaining weak inhibition should be overcome with increasing ascent
   and continues warm advection. Effective shear around 30-40 kt will
   support organized convection, with main storm mode expected to be
   clusters/line segments given linear forcing along the front.
   Damaging wind gusts and hail will be the primary threat with this
   activity. 

   Additionally, any more discrete cells along the front or that may
   develop ahead of the main line will experience strong SRH where
   backed low level winds closer to the surface low and near/south of
   the outflow boundary exist. 18z mesoanalysis also indicates STP
   values around 2-5. As such, a couple of tornadoes also appear
   possible. Given this tornado potential, one ore more watches may be
   needed to cover both the broader severe wind/hail threat in addition
   to the tornado threat.

   ..Leitman/Grams.. 08/14/2020

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

   ATTN...WFO...DLH...MPX...DMX...FGF...FSD...OAX...ABR...

   LAT...LON   41879477 41609549 41699623 42059681 42499720 42879730
               43739695 44579689 46289714 46609647 46709545 46529441
               46089397 45469338 44989336 44619326 44309331 43779342
               42849386 42099444 41879477