Mesoscale Discussion 1531

Issued

Aug 16, 2021, 6:26 AM EDT (10:26 UTC)

Expired

Aug 16, 2021, 9:00 AM EDT

In force

3 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

60%

County Franklin County, FL

The Tallahassee radar (KTLH), 95 km from the middle of the area, began a volume at 10:28 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

• Tornado Watch 441Aug 16, 8:25 AM EDT

167 
ACUS11 KWNS 161026
SWOMCD
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

Mesoscale Discussions in Florida, 2021Every mesoscale discussion in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.