Mesoscale Discussion 141

Mesoscale Discussion 0141
   NWS Storm Prediction Center Norman OK
   0959 AM CST Sun Mar 03 2019

   Areas affected...southern and central AL...western FL
   Panhandle...southwest and west-central GA

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

   Valid 031559Z - 031800Z

   Probability of Watch Issuance...95 percent

   SUMMARY...The initial signs of discrete convective development are
   occurring late this morning in the warm sector.  Rapid environmental
   changes are forecast to occur between 10am CST/11am EST and the mid
   afternoon.

   DISCUSSION...Visible satellite imagery shows widespread cloud cover
   across the destabilizing warm sector to the south of the primary
   frontal zone where the surface low is forecast to develop eastward
   across central AL into north-central GA later today.  Surface
   dewpoints over the FL Panhandle and far southern AL have risen
   around 3 degrees F in the past hour and are indicative of strong
   poleward moisture advection occurring as the surface cyclone
   develops.  The warming/moistening are contributing to MLCAPE
   increasing from near 0 J/kg to upwards of 1000-1500 J/kg by
   early-mid afternoon.  

   Late morning VAD data show around 35-45 kt southwesterly 700mb flow
   from KMOB/KBMX/KMXX/KEOX in central and southern AL but stronger
   flow (50-55 kt) is now being observed farther west in Jackson, MS
   (KDGX) and Slidell, LA (KLIX).  Models show the flow intensifying
   further over AL and GA this afternoon (55-60 kt 700mb).  The end
   result is a hodograph exhibiting little weakness (no veer-back-veer
   tendency or a weak layer of winds).  In summary, as moderate
   buoyancy and strong/veering flow through the profile combine with
   moist low levels, the threat for strong low-level mesocyclones
   associated with the discrete storms will increase, along with a
   corresponding risk for tornadoes of which a few may be strong.