Apr 6, 2019 1300 UTC Day 1 Convective Outlook

Day 1 Convective Outlook  

   NWS Storm Prediction Center Norman OK
   0747 AM CDT Sat Apr 06 2019

   Valid 061300Z - 071200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH THIS
   EVENING FROM PARTS OF CENTRAL TX TO THE ARK-LA-MISS...

   ...SUMMARY...
   Severe thunderstorms are expected from central/east Texas into the
   Ark-La-Miss region today and tonight. Damaging winds, large hail,
   and a couple of tornadoes are possible.

   ...TX to the Ark-La-Miss through tonight...
   An initial MCV over western OK will continue northeastward toward
   central KS today, in advance of the primary ejecting shortwave
   trough now over west TX.  The thunderstorm cluster responsible for
   the initial MCV weakened early this morning, leaving an outflow
   boundary across southwest OK and northwest TX.  Another MCS is
   moving northeastward along the outflow boundary in advance of the
   midlevel trough, fed by an increase in low-level moisture across
   north TX.  In advance of this convection, a surface warm front will
   continue moving northward into northeast TX, northern LA/southern AR
   and northwestern MS during the day.

   An MCS over north TX could persist into southern OK today before
   weakening, though convective evolution thereafter is uncertain.  A
   low-midlevel reflection of the primary ejecting trough appears to be
   related to a recent increase in convective cloud development from
   roughly San Antonio northeastward.  This general zone may see an
   increase in thunderstorm development by mid-late morning, and then
   loosely phase with the warm front as the convection spreads
   east-northeastward toward northeast TX and northern LA this
   afternoon.  It is also possible that the southern flank of another
   MCV with the ongoing north TX storms will contribute to additional
   storm development east-northeastward along the warm front this
   afternoon/evening.  Thus, one or more semi-organized clusters are
   expected from TX to the lower MS Valley today through late evening,
   with an accompanying threat for damaging winds and large hail.  A
   couple of tornadoes will also be possible with embedded supercells. 
   Overall, messy storm modes/evolution and early convection will
   contribute to substantial uncertainty.

   In the wake of the convection today, a second bout of thunderstorms
   is expected to spread across the Rio Grande into south central TX
   overnight, in advance of an upstream shortwave trough now over the
   lower CO River Valley.  Steep midlevel lapse rates and rich
   low-level moisture will drive MUCAPE in excess of 2000 J/kg, which
   favors a threat of damaging outflow winds and large hail from
   06-12z.