SPC AC 241943

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0143 PM CST Sat Nov 24 2018

   Valid 242000Z - 251200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH
   CAROLINA OUTER BANKS AREA...

   ...SUMMARY...
   A brief tornado and locally damaging winds may persist until roughly
   6 PM EST along the North Carolina coast.

   ...Discussion...
   Current forecast reasoning -- as described in the prior outlook and
   in SWOMCD #1656 -- continues to accurately portray the evolving
   convective scenario over the middle and southern Atlantic Coast
   regions.  One fairly well-developed supercell continues moving
   across Carteret County NC.  Limited risk for locally gusty winds
   and/or a brief tornado will exist with this cell, and possible a
   couple of others near the Outer Banks later on, prior to convection
   shifting further offshore as the parent upper system moves quickly
   across the region and into the western Atlantic this evening.

   ..Goss.. 11/24/2018

   .PREV DISCUSSION... /ISSUED 1020 AM CST Sat Nov 24 2018/

   ...Eastern NC...
   A vigorous shortwave trough over the southern Appalachians will
   reach the Mid-Atlantic States by this evening. An associated 1009-mb
   cyclone between Myrtle Beach and Wilmington will deepen as an 80-kt
   500-mb jet over TN ejects through the base of the trough. Latest
   NAM/RAP models are generally consistent in suggesting the cyclone
   will track more northward, inland across eastern NC along an
   inverted trough currently present through the VA Tidewater. However,
   given a broad swath of stratiform rain ahead of the cyclone and
   surface-based instability still offshore at present, this guidance
   is probably too aggressive with the degree of inland destabilization
   through the afternoon. Current thinking is that the surface cyclone
   should track closer to the coast/Outer Banks region, similar to the
   GFS. Rather large, curved hodographs will clearly favor low-level
   updraft rotation ahead of the low, but the degree of surface-based
   buoyancy will be critical to potential tornado and damaging wind
   hazards. Have made no adjustments to Marginal Risk delineation given
   the lack of confidence in the potential for NAM/RAP guidance to be
   accurate regarding evolution of the boundary layer this afternoon.

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