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Mesoscale Discussion 845
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   Mesoscale Discussion 0845
   NWS Storm Prediction Center Norman OK
   0125 PM CDT Fri May 26 2017

   Areas affected...Central and eastern Illinois and far western

   Concerning...Severe potential...Watch possible 

   Valid 261825Z - 262100Z

   Probability of Watch Issuance...60 percent

   SUMMARY...An area of convection over western Illinois will gradually
   intensify while moving eastward into the discussion area.  A WW will
   be considered around/just after 20Z.

   DISCUSSION...Convection over western Illinois is moving eastward
   along and just north of a subjectively analyzed surface boundary
   lifting slowly northward across central/eastern Illinois.  Along and
   south of this boundary, weak to moderate instability has developed
   in response to warming surface temperatures (nearing 80F) and low to
   mid-60s dewpoints.  This warm front will continue to lift northward
   slowly during the day, and the attendant increase of instability and
   lift associated with an approaching remnant mesoscale convective
   vortex over northwestern Illinois will foster scattered
   thunderstorms capable of hail and damaging wind gusts.  A few
   tornadoes will also be possible owing to backed surface flow in
   vicinity of the lifting warm front/surface boundary especially if
   convection can maintain a favorable (cellular) storm mode.

   Convective trends will be monitored for a possible WW issuance
   around or just after 20Z.

   ..Cook/Hart.. 05/26/2017

   ...Please see for graphic product...


   LAT...LON   40718928 40878886 40988838 41028772 41028729 40938658
               40728617 40268594 39758607 39428651 39398725 39398771
               39518852 39678924 39838962 40198968 40418956 40718928 

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