Mesoscale Discussion 1789
   NWS Storm Prediction Center Norman OK
   0336 AM CST Wed Nov 11 2020

   Areas affected...Parts of the southwestern Florida Peninsula and
   lower Keys

   Concerning...Severe potential...Watch possible 

   Valid 110936Z - 111200Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Potential for waterspouts might not be completely
   negligible with ongoing convection near southwestern Florida
   Peninsula coastal areas through daybreak.  By 9-11 AM EST, it is
   possible that the potential for a tornado or two could begin to
   increase around the Fort Myers and Port Charlotte areas.  While it
   is not yet certain that this will require a watch, trends will
   continue to be monitored for this possibility.

   DISCUSSION...As Eta migrates north-northeastward around 10 kts, VWP
   data indicate strengthening  wind fields in the 1-3 KM AGL layer
   contributing to enlarging, clockwise-curved low-level hodographs
   across the lower Florida Keys into southwestern Peninsula coastal
   areas.  This includes flow up to 50 kts as far east as Key West,
   dropping off to 30-40 kts at Miami.

   In the presence of a tropically moist boundary layer (including
   surface dew points in the mid 70s F) to the northeast and east of
   the circulation center, this has contributed to weak to modest
   sustained low-level mesocyclones within discrete ongoing convective
   development near Marathon into the Gulf waters near/northwest of the
   Everglades.  Given their current strength, and the probable presence
   of at least a shallow near-surface stable layer inland of the coast,
   the risk for tornadoes seems likely to remain low through daybreak. 
   Thereafter, with the onset of at least weak boundary-layer warming,
   some of these low-level mesocyclones could begin to pose increasing
   risk for producing a tornado.  

   Stronger low-level wind fields, associated potential low-level
   mesocyclone development, and boundary-layer destabilization could
   begin impacting coastal areas around Fort Myers and Port Charlotte
   as early as 14-16Z.

   ..Kerr/Edwards.. 11/11/2020

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

   ATTN...WFO...MFL...KEY...TBW...

   LAT...LON   26998251 27038199 26198148 25458062 25078074 24778114
               24718151 25448183 26358252 26998251