SPC AC 051935

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0235 PM CDT Fri Nov 05 2021

   Valid 052000Z - 061200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS
   AFTERNOON AND EVENING ACROSS PARTS OF THE CENTRAL AND SOUTHERN
   FLORIDA PENINSULA...

   ...SUMMARY...
   Strong thunderstorms may still impact parts of the central and
   southern Florida Peninsula late this afternoon and evening, and pose
   at least some risk for severe weather.

   ...20Z Outlook Update...
   Models continue to vary concerning surface frontal wave development
   across the eastern Gulf of Mexico into the western Atlantic, east of
   northern Florida coastal areas by late tonight.  However, the NAM
   appears too deep with the initial low over the eastern Gulf as it
   approaches coastal areas south of Tampa into early evening.  Most
   guidance maintains a weaker wave, with another wave forming along
   Atlantic coastal areas near/north of Cape Canaveral this evening
   before migrating offshore.

   As a result, low-level hodographs appear likely to remain fairly
   modest to weak across much of central and southern Florida, as a
   seasonably moist boundary layer destabilizes ahead of the
   approaching mid-level trough.  The leading edge of mid-level
   subsidence and drying, beneath a 50+ kt southwesterly 500 mb jet
   streak, does appear to be contributing to development of breaks in
   the convective cloud cover and precipitation which has slowed
   destabilization to this point. 

   With some insolation still possible, along with weak low-level warm
   advection into early evening, instability might become sufficient to
   support the initiation of isolated to widely scattered vigorous
   thunderstorms, in the presence of strong deep-layer shear.  If this
   occurs, stronger storms could pose the risk for locally damaging
   wind gusts.  A generally brief/weak tornado might still not be out
   of the question, but the potential for anything more sustained
   and/or stronger currently appears low.

   ..Kerr.. 11/05/2021

   .PREV DISCUSSION... /ISSUED 1108 AM CDT Fri Nov 05 2021/

   ...Portions of central and southern Florida...
   A zone of enhanced mid- and upper-level ascent continues to move
   slowly across central and southern Florida this morning per WV
   imagery, in advance of a dry slot that will nose into western
   Florida with time.  This should permit a period of relative decrease
   overall with respect to precipitation coverage across the peninsula
   during the day, while a surface warm front drifts northward with
   time.  Still, persistent scattered/showery convection and cloud
   cover should substantially limit heating/destabilization in most
   areas.

   At this time, it appears that the greatest potential for any
   diurnal, modest boost in heating will be across western portions of
   the peninsula as the dry slot spreads eastward/inland.  Any
   resulting/modest increase in CAPE would support potential for
   slightly more vigorous convection to spread onshore/inland starting
   later this afternoon.  Along with any such enhancement of
   convection, updraft intensity would be aided by gradually increasing
   deep-layer shear, occurring as a result the expected, modest
   strengthening of flow at all levels through the mid troposphere as a
   surface low approaches -- and eventually reaches -- western Florida
   during the evening hours.  

   Overall, expected environmental evolution suggests a relative
   increase in potential for a brief tornado or two, or a few instances
   of locally strong/damaging wind gusts, beginning late this afternoon
   focused on the west-central Florida area.  However, at this time
   uncertainty prevails as to whether risk will rise to a level that
   warrants an outlook upgrade.  As such, we will re-evaluate the
   scenario for the 20Z outlook update -- particularly related to
   thermodynamic evolution through the afternoon -- that will likely be
   a key variable with respect to any need to nudge severe risk
   category/probability upward for the evening hours.

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