Mesoscale Discussion 0120
   NWS Storm Prediction Center Norman OK
   0146 PM CST Wed Feb 12 2020

   Areas affected...Central into northern Mississippi

   Concerning...Severe potential...Watch possible 

   Valid 121946Z - 122145Z

   Probability of Watch Issuance...40 percent

   SUMMARY...At least a few severe storms are possible in the next few
   hours, going into early evening. Damaging wind gusts appear to be
   the primary threat, though a couple of tornadoes cannot be ruled
   out. Convective trends are being monitored for the need of a WW.

   DISCUSSION...A well defined mid-level trough continues to approach
   the southeast states, with a broad low-level mass response promoting
   moistening of the low-levels (i.e. a northward surge of upper 60s to
   near 70 F dewpoints), particularly across LA into central MS. In
   addition, breaks in the clouds from central MS southward have
   allowed for some diurnal heating, with temperatures warming into the
   mid 70s. Nonetheless, given the overall cloudy conditions, and poor
   mid-level lapse rates (mainly under 6 C/km based on latest
   mesoanalysis and the latest RAP forecast soundings) across the warm
   sector, overall instability is expected to be mediocre. MLCAPE is
   expected to be maximized in the 500-1000 J/kg range, and confined
   within tall, skinny vertical profiles. As such, robust convection is
   expected to be relatively sparse in nature.

   Still, deep-layer/low-level speed shear (40+ knots in the 0-1 km
   layer) is prevalent across the warm sector, with long, curved
   hodographs depicting a favorable kinematic environment for
   organized, rotating storms. Flow above 1 km however, appears to be
   unidirectional. With deep-layer winds bearing a strong parallel
   component of flow to the approaching cold front, much of the
   convection is expected to be linear in nature. While a forced line
   of convection is expected, the strong low-level speed shear and
   modest directional shear (yielding over 400 m2/s2 effective SRH) may
   promote the development of a couple of tornadoes, where QLCS
   circulations may coincide axes of locally higher buoyancy.

   All 12Z HREF members initiate a squall line along the cold front by
   20-22Z, though the trend among the latest HRRR runs show less
   vigorous convection overall. Given the aforementioned limitations to
   the thermodynamic environment and associated weakening trends among
   model guidance, confidence in the necessity of a WW issuance remains
   modest at this time. Trends will continue to be monitored for a WW
   issuance.

   ..Squitieri/Thompson.. 02/12/2020

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

   ATTN...WFO...BMX...HUN...MEG...JAN...

   LAT...LON   32269094 33559000 34458906 35008815 34938776 34798760
               34478752 33938760 33238790 32558825 32308856 32068914
               31949028 32269094