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Dec 15, 2017 0830 UTC Day 3 Severe Thunderstorm Outlook
Updated: Fri Dec 15 07:09:25 UTC 2017 (Print Version | 20171215 0830Z Day 3 shapefile | 20171215 0830Z Day 3 KML)
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 Forecast Discussion
   SPC AC 150709

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0109 AM CST Fri Dec 15 2017

   Valid 171200Z - 181200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE LOWER MISSISSIPPI VALLEY...

   ...SUMMARY...
   Thunderstorms will likely develop on Sunday across parts of the
   central Gulf Coast region including the lower Mississippi Valley. A
   few damaging wind gusts and a marginal tornado threat will be
   possible.

   ...Lower Mississippi Valley...
   A shortwave trough will move quickly northeastward into the mid
   Mississippi Valley on Sunday as southwest mid-level flow remains in
   place across the Gulf Coast Region. At the surface, moisture
   advection will continue across the lower Mississippi Valley where
   surface dewpoints are forecast to reach the lower to mid 60s F
   across southeastern Louisiana and southern Mississippi by midday.
   Isolated to scattered thunderstorms are forecast to be ongoing in
   southwestern Louisiana at the beginning of the period with this
   convection spreading eastward into the lower Mississippi Valley by
   early afternoon. NAM and GFS forecast soundings at New Orleans,
   Louisiana and Mobile, Alabama at 21Z Sunday afternoon show weak
   instability with strong deep-layer shear. Although MLCAPE values are
   only forecast to be in the 250 to 500 J/kg range, 0-6 km shear
   values could be as high as 50 kt. This would be enough for a
   marginal severe threat making isolated damaging wind gusts possible
   with the stronger thunderstorms. 0-1 km shear of 25 to 30 kt will
   also make storm rotation possible and a marginal tornado threat can
   not be ruled out. As moisture advection continues and the shear
   environment is maintained during the evening and overnight period, a
   marginal severe threat could persist across the region.

   ..Broyles.. 12/15/2017

   CLICK TO GET WUUS03 PTSDY3 PRODUCT

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0830Z

        
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Page last modified: December 15, 2017
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