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Mesoscale Discussion 1692
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   Mesoscale Discussion 1692
   NWS Storm Prediction Center Norman OK
   0523 PM CDT Tue Sep 15 2020

   Areas affected...Southern AL and the FL Panhandle

   Concerning...Severe potential...Tornado Watch likely 

   Valid 152223Z - 160030Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A tornado threat will continue into the evening and
   overnight hours along the FL Panhandle coastal region. A new tornado
   watch will be issued to replace WW 489 by 23 UTC.

   DISCUSSION...Per recent NHC guidance, Hurricane Sally continues to
   move north towards southern AL at around 2 mph. This slow motion
   will allow a strongly sheared environment (around 600 m2/s2 0-1 km
   SRH noted on the KEVX VAD) to linger over southern AL and the FL
   Panhandle. However, the tornado threat may be somewhat conditional
   on sufficient instability to support inland convection. Recent IR
   satellite trends show numerous convective towers developing offshore
   over the Gulf Coast, but only weak/transient convection inland. This
   trend is reflected in recent RAP Mesoanalysis, which shows only
   250-500 J/kg MLCAPE inland - largely due to persistent stratiform
   rain over the region. Confidence in sufficient instability is lowest
   across southern AL/the Mobile Bay area where easterly low-level
   trajectories are advecting in lower theta-e air from the FL
   Panhandle into the region and reducing instability. However,
   sufficient instability immediately offshore will continue to support
   the potential for waterspouts moving inland along the coastal areas
   in the coming hours for the FL Panhandle. As mid-level dry air
   continues to move inland overnight and low-level onshore flow
   increases, the potential for sustained inland convection may
   increase and support a tornado threat.

   ..Moore/Thompson.. 09/15/2020

   ...Please see for graphic product...


   LAT...LON   30628751 30908746 31168715 31188660 31038580 30798488
               30238372 29868364 29728378 29718418 29468468 29468512
               29908578 30218662 30208688 30258716 30378738 30628751 

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