SPC AC 200757

   Day 3 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   0257 AM CDT Sun Mar 20 2022

   Valid 221200Z - 231200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
   SOUTHERN LOUISIANA INTO SOUTHERN MISSISSIPPI...

   CORRECTED MRGL RISK LINE

   ...SUMMARY...
   A substantial severe weather event -- including potential for
   significant tornadoes -- remains evident over the Lower Mississippi
   Valley/central Gulf Coast region Tuesday.

   ...Synopsis...
   A upper trough and expansive area of highly amplified cyclonic flow
   will shift gradually eastward across the central U.S. Tuesday, as a
   closed low likely evolves over the Mid Missouri Valley area with
   time.

   At the surface, a low is forecast to move across the Missouri
   vicinity through the day, with a trailing cold front forecast to
   reach the Mississippi Delta region during the afternoon.  Late in
   the period, the low should reside over the Illinois vicinity, with
   the cold front extend southward across Kentucky/Tennessee/Alabama to
   the Florida Panhandle.

   ...Lower Mississippi/central Gulf Coast States...
   A regional severe-weather outbreak -- including potential for
   several tornadoes (a few potentially significant) remains evident
   for Tuesday.  Severe storms -- including tornado risk -- will likely
   be ongoing at the start of the period across the Sabine River Valley
   area of east Texas/western Louisiana, as a surface cold front moves
   steadily eastward.

   As southerly flow ahead of the front continues to advect high
   theta-e air northward from the Gulf, limited heating will allow
   destabilization to occur through the morning and into the afternoon.
   At this time, it appears that in addition to storms occurring ahead
   of the advancing front, pre-frontal cellular convection will also
   evolve through late morning/afternoon.  With strong low-level
   southerly flow (50 to 70 kt at 850mb) in place, and 70 to 90 kt
   mid-level westerlies overspreading the region, shear very favorable
   for strong updraft rotation and low-level mesocyclones will exist. 
   As such, potential for strong tornadoes will exist with the evolving
   supercell storms ahead of the front.  Additionally, tornadoes (along
   with damaging winds and hail) will be likely with storms shifting
   eastward in tandem with the cold front.

   Into the evening and overnight, severe risk -- including potential
   for tornadoes and damaging winds -- will continue.  While
   diminishing somewhat later in the period, threat will likely spread
   across southern Alabama and into the Florida Panhandle.

   ..Goss.. 03/20/2022

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