SPC AC 261236

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0736 AM CDT Sun Mar 26 2023

   Valid 261300Z - 271200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL LA TO
   CENTRAL/SOUTHERN AL...

   ...SUMMARY...
   Episodic severe thunderstorms will persist through at least this
   evening across a large swath of the Southeast States. A few strong
   tornadoes and very large hail should accompany the most intense
   storms, particularly from central Louisiana across central to
   southern portions of Mississippi and Alabama.

   ...Southeast...
   Multiple rounds of severe thunderstorms are anticipated this morning
   through at least this evening, before likely waning overnight. 

   Round one will be associated with a mix of supercells and clusters
   near a quasi-stationary front through central portions of AL/GA. The
   leading portion of this activity will likely consolidate and grow
   upscale into a forward-propagating MCS across the Savannah Valley to
   the coastal Carolinas before it progresses offshore in the early
   afternoon. Pervasive warm-sector cloud cover should slow
   boundary-layer heating and may limit a more widespread severe wind
   threat. Nevertheless, ample buoyancy with MLCAPE of 1500-2000 J/kg
   and around 50-kt effective bulk shear will support potential for a
   couple tornadoes, along with a mix of large hail and damaging winds.

   In the wake of this leading activity, weak low-level isentropic
   ascent should persist across residual composite front/outflow. This
   should be sufficient to sustain regenerative supercell development
   focused on central AL, while warm-sector low-level confluence will
   probably support scattered storms emanating from the central Gulf
   Coast. With upper 60s to low 70s surface dew points common across
   this region, even limited boundary-layer heating will support a
   persistent severe threat. However, bulk of guidance suggests
   low-level hodograph curvature within the warm sector should remain
   modest until this evening, lowering confidence in a more substantial
   tornado threat through mid-afternoon.

   A third corridor of significant severe potential should evolve
   across the Sabine to Lower MS Valleys this afternoon and evening.
   Below-average confidence exists in more specific timing this
   afternoon given the large spread in guidance with handling the
   initially weak forcing for ascent via low-level warm advection. Even
   so, low-level wind fields will strengthen into late afternoon in
   response to a shortwave trough ejecting from the Southwest to the
   Mid-MS Valley. This should support peak tornado potential during the
   late afternoon to early evening, particularly where semi-discrete
   supercells can become anchored along pre-existing outflow boundaries
   as the largest buoyancy today is expected to develop across
   southeast LA and southern MS. The setup will support potential for a
   few intense supercells capable of strong tornadoes and very large
   hail. With time, convection should consolidate into at least a small
   MCS, propagating eastward along the composite front/large-scale
   outflow this evening with a mix of all hazards anticipated. 

   ...IL/IN...  
   Low-topped thunderstorms should develop this afternoon across
   eastern IL as a low-amplitude shortwave trough overspreads this
   region. Although low-level moisture should remain limited, enough
   weak instability should still develop through the day as mid-level
   temperatures cool with the shortwave trough passage. With some
   enhanced low/mid-level flow forecast, any convection that can
   develop and be sustained may pose an isolated damaging wind risk.

   ..Grams/Goss.. 03/26/2023

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