Mesoscale Discussion 1994
   NWS Storm Prediction Center Norman OK
   1020 PM CDT Fri Sep 20 2019

   Areas affected...northern parts of the Nebraska Panhandle into
   western and central South Dakota

   Concerning...Severe Thunderstorm Watch 655...

   Valid 210320Z - 210515Z

   The severe weather threat for Severe Thunderstorm Watch 655
   continues.

   SUMMARY...Local severe risk continues with scattered, vigorous
   storms over portions of WW 655.

   DISCUSSION...latest radar loop shows scattered strong/locally severe
   storms moving northeast across western South Dakota, and adjacent
   portions of the Nebraska Panhandle.  While cool/stable air continues
   to surge southward across eastern Wyoming, a relatively
   moist/unstable airmass persists across much of central South Dakota,
   downstream of the ongoing storms.  As such, local severe risk --
   mainly in the form of hail -- will likely continue over the next few
   hours.

   With an airmass largely uncontaminated by prior convection
   continuing across north-central South Dakota, northeast of WW 665,
   some severe risk could spread out of the WW and into these areas
   over the next couple of hours.  Though this region was previously
   included within now-expired WW 654, expansion of ww 655 into these
   areas may be required, if convection -- and associated severe risk
   -- increases in conjunction with the strengthening low-level jet.

   ..Goss.. 09/21/2019

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

   ATTN...WFO...FSD...ABR...BIS...LBF...UNR...CYS...

   LAT...LON   42230098 42080194 42610327 42890316 43720321 44220348
               44850316 45730198 45989966 45859833 44589858 43179951
               42230098