Storm Prediction Center Mesoscale Discussion 139

   Mesoscale Discussion 0139
   NWS Storm Prediction Center Norman OK
   0644 PM CST Tue Mar 04 2025

   Areas affected...portions of central into northern Alabama

   Concerning...Severe potential...Watch possible 

   Valid 050044Z - 050215Z

   Probability of Watch Issuance...60 percent

   SUMMARY...The threat for strong to potentially severe thunderstorm
   wind gusts is increasing with the approach of a squall line. A WW
   issuance is possible pending upward trends in intensity for the
   northern portions of the squall line and any thunderstorm ahead of
   the line.

   DISCUSSION...A convective squall line continues to progress eastward
   amid very strong synoptic forcing as a surface low continues to
   intensify over the Midwest. A 500 mb wind maxima is approaching
   portions of the Southeast from the Lower Mississippi Valley as
   low-level moisture advection increases ahead of the squall line.
   Damaging non-thunderstorm wind gusts have already been reported in
   central AL, indicating that deep-layer synoptic wind fields could
   easily support severe convective gusts with any efficient downward
   momentum transport within the approaching squall line. The 00Z BMX
   sounding depicts a mixed boundary layer extending past 850 mb, with
   an additional dry layer centered over 700 mb, suggesting that
   downward mixing from evaporative cooling is quite plausible.
   Therefore, conditions will continue to be monitored for the need of
   a Severe Thunderstorm Watch if northern portions of the squall line
   continues to increase.

   ..Squitieri/Guyer.. 03/05/2025

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

   ATTN...WFO...BMX...HUN...

   LAT...LON   33098820 34178797 34748696 34508607 33818555 33158542
               32878568 32928653 32998731 33098820