SPC AC 140729

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CDT Thu May 14 2020

   Valid 161200Z - 171200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ALONG THE TX
   GULF COAST INTO EAST TX...

   ...SUMMARY...
   Isolated strong to severe thunderstorms are expected from the Texas
   Gulf Coast into the East Texas on Saturday.

   ...Southern Plains...
   A convective line will likely be moving into portions of south TX
   early Saturday morning. The strength/organization and timing of this
   line are uncertain at this forecast range, but an unstable air mass
   will be in place ahead of it, contributing to a severe risk as the
   line moves through. More refinements and possibly higher
   probabilities may be need in later outlooks once convective details
   become more certain.

   Shortwave trough moving into the southern Plains late Friday (and
   responsible for the convective line mentioned above) will likely
   have developed into a closed low over central TX by early Saturday,
   aided by widespread showers/thunderstorms and resulting convective
   feedback. This upper low is then expected to drift slowly
   eastward/northeastward, eventually reaching the Arklatex by early
   Sunday morning. The abundance of showers and thunderstorms
   surrounding this upper low will eliminate the steep lapse rates
   previously in place, while the attendant cloudiness also reduced
   heating. Even so, ample low-level moisture will help support modest
   instability and continued thunderstorm development throughout the
   day. Low-level flow will strengthen throughout the eastern periphery
   of the upper cyclone (i.e. over east TX), contributing to vertically
   veering low-level winds, and low-probability potential for a few
   stronger storms capable of damaging wind gusts and/or a brief
   tornado.

   ...Central Plains into the Mid MS Valley...
   Shortwave trough is forecast to move across the northern/central
   Plains toward the Upper Midwest on Saturday. At the same time, an
   attendant surface low will move from KS into the Mid MS Valley while
   an associated cold front moves across eastern KS, western/central
   OK, and much of MO. Thunderstorms are expected along this front, but
   vertical shear will be weak. This should limit both updraft
   strength/persistence and the overall severe threat.

   ..Mosier.. 05/14/2020

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