SPC AC 180537

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1237 AM CDT Wed Jul 18 2018

   Valid 191200Z - 201200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ...

   ...SUMMARY...
   A marginal severe threat will be possible on Thursday across parts
   of the upper Mississippi Valley.

   ...Upper Mississippi Valley...
   An upper-level trough will move into the upper Mississippi Valley on
   Thursday as a 45 to 55 kt mid-level jet moves across northeastern
   sections of the central Plains. At the surface, a low is forecast to
   move into the upper Mississippi Valley as a cold front advances
   eastward across the mid Missouri Valley. A moist airmass should be
   in place ahead of the front with surface dewpoints in the mid to
   upper 60s F. As a result, a corridor of moderate instability appears
   possible ahead of the front by Thursday afternoon. Elevated
   convection may ongoing Thursday morning ahead of the front near the
   axis of the low-level jet. This convection is forecast to weaken by
   early afternoon with new surface-based thunderstorms developing
   along the front. These storms are forecast to move eastward across
   the Upper Mississippi Valley during the mid to late afternoon and
   early evening. Moderate deep-layer shear along the front, evident on
   forecast soundings, should enable the stronger cells to have
   marginally severe wind gusts and hail. The magnitude of the severe
   threat will likely depend upon how much instability materializes
   across the moist sector. At this time, forecast instability appears
   low enough to keep the threat at marginal.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   2%     - Marginal
   Wind:      5%     - Marginal
   Hail:      5%     - Marginal

   ..Broyles.. 07/18/2018

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z