Strong to severe thunderstorms appear possible across Alabama on Sunday during the afternoon and evening hours. At this time, damaging winds, hail, and tornadoes are possible, with the greatest threat along and south of I-20.


Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 AM CDT Sat Apr 18 2020

   Valid 191200Z - 201200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE SABINE
   RIVER EASTWARD INTO SOUTH CAROLINA...

   ...SUMMARY...
   Severe storms are likely Sunday from east Texas to South Carolina.
   The greatest threat appears to be from Louisiana to Georgia, with
   significant severe including tornadoes and damaging winds. Large
   hail is likely over much of the area as well.

   ...Synopsis...
   A progressive shortwave trough will move from the southern Plains
   into the lower MS Valley during the day, and will continue to the
   GA/SC/NC coast by Monday morning. The entire southeastern region
   will be under the influence of strong westerly winds aloft which
   will strengthen as the upper trough approaches. Southwesterly 850 mb
   winds will increase in response to the wave, reaching 50+ kt by 00Z
   from MS eastward to the coast.

   At the surface, low pressure will develop near the ArkLaTex by late
   afternoon as a warm front lifts north across the southeastern
   states, oriented roughly from southern AR into northern MS, AL, and
   GA at 18Z. Meanwhile, a cold front/dryline will develop over east
   TX. Across the warm sector, rich moisture with 65-70 F dewpoints
   will result in moderate instability. The low, likely associated with
   widespread convection, will translate eastward along the synoptic
   front overnight, reaching NC by 12Z Monday.

   ...Southeastern states...
   Substantial instability will already be in place Sunday morning from
   TX into the lower MS Valley, with rapid destabilization expected
   behind the warm front farther east into GA. Midlevel lapse rates
   aloft will be modestly steep, averaging 6.5 to 7.0 C/km. Early day
   storms related to warm advection will be present over AL and GA, and
   they will likely be elevated with perhaps a hail threat initially.
   As the air mass warms, a wind or tornado threat could develop in the
   vicinity of this activity as it continues east.

   To the west, storms are likely to be severe by 18Z near the Sabine
   Valley/ArkLaTex. Here, long hodographs but modest low-level SRH may
   result in cells capable of very large hail, and perhaps an eventual
   MCS with damaging-wind threat. A severe wind corridor may thus
   develop during the day across northern MS, AL, and GA. 

   There is also a threat of daytime supercells, possibly tornadic, as
   the small capping inversion is eroded by early afternoon. During the
   evening and overnight, low-level shear will increase further, and
   models suggest southern AL into GA may be a favored area for
   tornadoes. Bows or isolated supercells are possible into SC early
   Monday morning as the relatively cooler air mass is destroyed by the
   warm front.