Mesoscale Discussion 1700
   NWS Storm Prediction Center Norman OK
   0927 AM CDT Thu Sep 17 2020

   Areas affected...The Carolina coastal plain

   Concerning...Tornado Watch 492...

   Valid 171427Z - 171630Z

   The severe weather threat for Tornado Watch 492 continues.

   SUMMARY...Potential for tornadoes is expected to increase through
   early to mid afternoon, with a strong tornado or two possible.

   DISCUSSION...As the shearing remnants of Sally gradually migrate
   east-northeastward toward the Carolinas, vigorous convective
   development is already underway across the South Carolina coastal
   plain, with  an isolated sustained supercell ongoing near/east of
   Orangeburg SC.  This is occurring along a surface warm frontal zone
   which extends east-northeastward across the South Carolina coastal
   plain, north of the Myrtle Beach area, into immediate North Carolina
   coastal areas.  At least some further inland advancement of this
   front seems probable through early afternoon, particularly across
   the North Carolina coastal plain.

   Near the nose of a 30-40 kt southerly 850 mb jet, now curving across
   southeast Georgia into the South Carolina Piedmont, and slowly
   shifting eastward, near surface vertical shear will become maximized
   along this front as the moist boundary layer destabilizes with at
   least weak to modest boundary layer warming through early afternoon.
   This environment seems likely to become increasingly conducive to
   tornadic development through 18-20Z, and could include the risk for
   a strong tornado.

   ..Kerr.. 09/17/2020

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...RAH...ILM...CHS...CAE...

   LAT...LON   34098075 35087945 35297860 34617859 34187871 33057998
               32708062 33628088 34098075