Mesoscale Discussion 1916
   NWS Storm Prediction Center Norman OK
   0625 PM CDT Mon Sep 02 2019

   Areas affected...portions of extreme southeastern ND...extreme
   northeastern SD...central/southern MN...western WI.

   Concerning...Severe Thunderstorm Watch 632...

   Valid 022325Z - 030100Z

   The severe weather threat for Severe Thunderstorm Watch 632
   continues.

   SUMMARY...A severe bow echo and related complex of convection will
   continue to translate southeastward across the remainder of watch
   632 over the next 1-2 hours.  The related severe-wind threat will
   persist farther southeastward toward parts of western WI through the
   evening, and another watch will be coordinated with affected local
   NWS offices soon.

   DISCUSSION...Surface mesoanalysis shows a warm front from
   northwestern SD southeastward near a low over west-central SD, then
   east-southeastward to eastward across the FSD area and extreme
   northern IA.  The warm front is forecast to move slowly northward
   through the remainder of the evening.  However, the air mass north
   of the warm front only gradually stabilizes with northward extent at
   the surface.  That stable layer also is shallow, based on modified
   model soundings and the ability of the complex to penetrate that
   stable layer with multiple significant-severe gusts in Stutsman
   County SD.  Objective mesoanalysis data appear to be underdone with
   MUCAPE north of the surface warm front, based on the behavior of the
   convection so far.  

   The low levels above the shallow stable layer will become more
   favorable as warm advection continues and perhaps strengthens
   somewhat, with an intensifying preconvective LLJ in mass response to
   the upshear shortwave trough aloft.  Meanwhile, 45-60-kt
   effective-shear vectors, aligned nearly parallel to the
   theta-e/instability gradient, will support a continued southeastward
   thrust of a cold pool that already is accompanied by a robust
   thermal/isallobaric perturbation.  Given these factors, another
   severe thunderstorm watch will be required.

   ..Edwards.. 09/02/2019

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

   ATTN...WFO...DLH...ARX...MPX...FGF...FSD...ABR...BIS...

   LAT...LON   46029867 46189773 46579691 47019667 47309666 47509679
               46189235 45549116 44929129 44539198 44029320 44099439
               44599564 45639766 45969838 46029867