SPC AC 120730

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0230 AM CDT Wed Mar 12 2025

   Valid 141200Z - 151200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE MIDDLE MISSISSIPPI VALLEY TO THE TENNESSEE VALLEY...

   ...SUMMARY...
   A regional outbreak of severe storms is expected across much of the
   Mississippi Valley, eastward to the Lower Ohio and Tennessee Valleys
   late Friday afternoon into early Saturday morning. All severe
   hazards are possible, including swaths of intense winds and
   tornadoes.

   ...MS/Lower OH/TN Valleys...

   A large cyclone will rapidly intensify as it lifts northeast across
   the central Plains to the Upper Midwest on Friday. A 100+ kt
   southwesterly jet streak at 500 mb will overspread portions of the
   Ozarks/Mid-MS Valley, while a 60-70 kt low-level jet overspreads
   much the Mid-South and Mid-MS/Lower OH Valleys during the late
   afternoon into the overnight hours. Northward extent of deeper Gulf
   moisture (60s F dewpoints) will likely remain south of southeast
   MO/southern IL/western KY, with more modest 50s F dewpoints
   expanding northward into southeast MN/southern WI and eastward
   toward the Lower OH Valley. Despite the more modest moisture across
   the northern half of the outlook area, cold temperatures aloft will
   support steep midlevel lapse rates and at least weak instability. 

   A strongly forced QLCS is expected to develop along a surface
   dryline as the mid/upper jet impinges on the Ozarks vicinity by late
   afternoon or early evening. Intense forcing and deep-layer wind
   fields will maintain an organized QLCS into the nighttime hours.
   Strong daytime heating and mixing of the boundary layer ahead of the
   QLCS will further promote swaths of severe/damaging gusts, some of
   which may be greater than 65 kt. While moisture will be somewhat of
   a limiting factor, QLCS tornadoes also will be possible.

   Convection may develop later across AR into the TN Valley/Deep
   South. However, deeper Gulf moisture will be in place across this
   region (possible mid/upper 60s F). This will support stronger
   instability amid supercell wind profiles. Large-scale ascent will be
   more subtle across this area, but sharpening of the dryline across
   AR and low-level confluence should support convective development
   during the evening. Initial supercells may grow upscale into a line
   moving across portions of AR/TN/northern MS/AL. An attendant risk of
   strong tornadoes and swaths of damaging/potentially significant wind
   gusts is expected across the Mid-South with this activity.

   A more conditional risk for overnight supercells exists across parts
   northern/central MS/AL. The environment could support intense
   supercells capable of producing large hail and strong tornadoes this
   far south, but forcing mechanisms will be weak. Trends will be
   monitored and future outlook adjustments may be needed.

   ..Leitman.. 03/12/2025

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z