SPC AC 130828

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0228 AM CST Fri Jan 13 2017

   Valid 151200Z - 161200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   WEST AND CENTRAL TEXAS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHERN PLAINS...

   ...SUMMARY...
   A severe threat with large hail and isolated wind damage will be
   possible on Sunday across parts of the southern Plains.

   ...Southern Plains...
   An upper-level low will move northeastward across southern New
   Mexico on Sunday as a negatively tilted upper-level trough moves
   into the Rio Grande Valley. Thunderstorm activity could be ongoing
   just ahead of the upper-level trough across far west Texas into far
   southeastern New Mexico at the start of the period. The models are
   consistent with moving this convection slowly eastward across the
   southern high Plains during the day on Sunday. At the surface, a
   trough is forecast to move into west Texas as a cold front advances
   from west to east from the Pecos Valley into western parts of the
   Texas Hill Country. Surface dewpoints ahead of the front will likely
   be 50s F with weak instability developing by afternoon.

   The greatest potential for a severe threat would be just ahead of
   the mid-level jet on the southern end of a cluster of storms
   forecast to be located near San Angelo by afternoon. This threat
   would extend southward toward the Rio Grande Valley where storms are
   forecast to have access to the greatest instability. NAM forecast
   soundings valid 00Z/Monday just to the south of San Angelo show a
   surface dewpoint of 57 F, MLCAPE of 700 J/kg, 0-6 km shear near 60
   kts and steep lapse rates from 700 to 500 mb. This should be enough
   for a supercell threat with isolated large hail associated with the
   stronger updrafts. A veering wind profile with height may also help
   downdrafts produce damaging wind gusts. Further to the north into
   parts of northwest Texas, surface dewpoints will not be as high but
   strong deep-layer shear and steep mid-level lapse rates may be
   enough for hail and isolated damaging wind gusts especially if a
   line of storms can organize during the late afternoon.

   ..Broyles.. 01/13/2017

   CLICK TO GET WUUS03 PTSDY3 PRODUCT

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