ZCZC SPCSWOMCD ALL
ACUS11 KWNS 161026 
SPC MCD 161026 
FLZ000-161300-

Mesoscale Discussion 1531
NWS Storm Prediction Center Norman OK
0526 AM CDT Mon Aug 16 2021

Areas affected...Parts of the Florida Big Bend vicinity

Concerning...Severe potential...Watch possible 

Valid 161026Z - 161300Z

Probability of Watch Issuance...60 percent

SUMMARY...An initial period with increasing potential for a couple
of tornadoes, in association with Tropical Storm Fred, may develop
near Apalachicola eastward along the coastal Florida Big Bend as
early as 9-11 AM EDT.  Trends are being monitored for the
possibility of a Tornado Watch.

DISCUSSION...As Tropical Storm Fred continues a slow northward
migration toward Florida Panhandle coastal areas just to the west of
the Big Bend, a number of discrete supercell structures have been
evident within at least one prominent narrow band of thunderstorms
along its eastern periphery.  Some of these have been wrapping
northward/northwestward, to the east and northeast of the leading
mid/upper circulation center, and it appears that this could begin
impacting St. Vincent/St. George Islands and adjacent Florida Big
Bend coastal areas, eastward toward Apalachee Bay, as early as
13-15Z this morning.  Latest objective instability analysis suggests
that it may take several more hours, with the approach of the
trailing low-level circulation, for the more substantively unstable
boundary-layer air to spread inland in the wake of a leading shield
of precipitation.  However, it might not be out of the question that
this could still be accompanied by an initial period of increasing
potential for a couple of relatively short-lived tornadoes.

..Kerr/Edwards.. 08/16/2021

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

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

LAT...LON   29748534 29938466 29798427 29558462 29508522 29748534 

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