Mesoscale Discussion 1697
   NWS Storm Prediction Center Norman OK
   0208 PM CDT Wed Sep 16 2020

   Areas affected...Parts of northern Florida and the Florida Panhandle
   and adjacent southwestern Georgia

   Concerning...Tornado Watch 491...

   Valid 161908Z - 162115Z

   The severe weather threat for Tornado Watch 491 continues.

   SUMMARY...At least isolated thunderstorms capable of producing
   tornadoes remain possible through 7 PM EDT.  It is unclear how much
   longer an appreciable risk for tornadoes will continue thereafter,
   but it is possible that a new tornado watch may be needed for this
   evening across parts of southern Georgia and northern Florida.

   DISCUSSION...Substantive boundary-layer warming has now occurred as
   far north as the southern tier counties of Georgia (including the
   Valdosta, Thomasville and Bainbridge areas), where surface dew
   points have increased into the mid 70s F.  This is focused along a
   remnant frontal zone, where near surface vertical shear may now be
   maximized, near the eastern periphery of the core of stronger
   southerly 850 mb flow.  

   There may be considerable further weakening of this flow into early
   evening, with little eastward progression, as the low-level
   circulation center of Sally only very slowly migrates
   east-northeastward near the western Alabama/Florida state border
   vicinity.  However, despite these trends, the environment remains
   potentially conducive to occasionally strengthening low-level
   mesocyclones within and ahead of bands of convection to the east of
   the circulation center.  This may be accompanied by a risk for
   tornadoes, particularly in any rapidly intensifying storms aided by
   increasing inflow of boundary-layer CAPE on the order of 1000-2000
   J/kg, in the peak late afternoon warmth.

   ..Kerr.. 09/16/2020

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

   ATTN...WFO...JAX...TAE...

   LAT...LON   31168491 31208470 31458351 30808292 29998360 30088407
               30028477 30488471 30978482 31168491