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Mesoscale Discussion 998
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   Mesoscale Discussion 0998
   NWS Storm Prediction Center Norman OK
   0317 PM CDT Mon Jun 12 2017

   Areas affected...northern Wyoming and southern Montana

   Concerning...Severe potential...Watch likely 

   Valid 122017Z - 122145Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Thunderstorms are beginning to form over central Wyoming. 
   Coverage and intensity of storms are expected to increase throughout
   the afternoon hours, as they spread northward over time.  Large hail
   and damaging winds will be the primary severe weather threats from
   the strongest storms, likely requiring a watch.

   DISCUSSION...Strong insolation has led to destabilization across
   central and northern Wyoming in advance of an upper-level low over
   northeastern Nevada.  As the upper-low approaches the area,
   mid-level ascent will favor increasing storm coverage and intensity.
   With low 50s F dewpoint temperatures holding across much of the
   region, MLCAPE values will approach 1000 J/kg. The instability
   coupled with effective deep-layer shear around 50 knots will be more
   than sufficient to support rotating updrafts.  Large hail and
   damaging winds will be the primary severe weather hazards.  Severe
   storm coverage is expected to be sufficient to require a watch.

   ..Jirak/Hart.. 06/12/2017

   ...Please see for graphic product...


   LAT...LON   42810663 42810734 42860839 43140915 43520956 44051008
               44551103 45091166 45591163 45901105 45851020 45810801
               45670670 45450594 44780566 43720598 42810663 

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