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Mesoscale Discussion 1331
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MD 1331 graphic

   Mesoscale Discussion 1331
   NWS Storm Prediction Center Norman OK
   0257 PM CDT Mon Jul 17 2017

   Areas affected...Portions of the northern Plains and upper
   Mississippi Valley

   Concerning...Severe potential...Watch likely 

   Valid 171957Z - 172100Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Thunderstorms will continue to develop across the region
   through this evening, with an attendant threat of damaging winds,
   large hail, and perhaps a tornado. Watch issuance is likely within
   the next hour.

   DISCUSSION...A cumulus field continues to organize across portions
   of NE South Dakota, SE North Dakota, and western Minnesota this
   afternoon, as a cold front and associated low pressure shift across
   the region. Surface heating (i.e., temperatures in the 90s) has
   combined with sufficient boundary-layer moisture and instability
   aloft to promote MLCAPE values upwards of 1500-2500 J/kg this
   afternoon. While mid-level westerly flow remains modest, veering of
   winds with height has provided around 30-40 kt of effective shear.
   Combined with ample mid-level buoyancy, a mixture of supercells and
   multicell clusters will likely organize over the next few hours,
   with a resultant threat of damaging winds and large hail.
   Additionally, while low-level flow remains relatively weak, ample
   boundary-layer moisture and backed flow with eastward extent may
   favor a tornado or two as well this evening. As such, watch issuance
   is expected within the next hour.

   ..Picca/Hart.. 07/17/2017

   ...Please see for graphic product...


   LAT...LON   45199575 45189698 45509747 46309777 46659766 46819738
               47209646 47569451 47529304 47479248 47059216 46309220
               45619236 45269418 45199575 

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