ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 280848
   SPC AC 280848

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0348 AM CDT Tue Mar 28 2023

   Valid 311200Z - 051200Z

   ...DISCUSSION...
   ...Day 4/Friday -- Arklatex and Mid-MS Valley, East to OH/TN
   Valleys...

   A complex forecast scenario remains for Day 4/Friday, with a large
   area of severe potential expected from the Arklatex into the Mid-MS
   Valley, eastward to portions of the OH and TN Valleys. A strong
   mid/upper trough is forecast to eject eastward across the Plains and
   Midwest. Intense deep-layer southwesterly flow will overspread the
   region as a surface low deepens over IA and shifts east/northeast
   across the Great Lakes. A strong cold front attendant to the low
   will sweep across the region, while strong southerly low-level flow
   transports 60s surface dewpoints northward across the Midwest ahead
   of the front. A bi-modal severe threat still appears possible, with
   one area of enhanced potential possible closer to the surface low,
   and another further south along the cold front in the Mid-South
   vicinity.
    
   Some forecast details still remain uncertain, including the
   amplitude of the trough, and quality of northward moisture
   return/destabilization over the Midwest.

   Surface dewpoints will be lower near the surface low over IA and
   into parts of MO/IL/and the Ohio Valley. However, stronger
   large-scale ascent and more intense wind fields will be focused over
   the Midwest. These areas also may remain cooler due to early day
   showers and cloud cover in the strong warm advection regime.
   Nevertheless, a tornado threat near the surface low still appears
   possible. With time, upscale growth into a line tracking across the
   Midwest seems reasonable given strong forcing and deep-layer shear
   parallel to the cold front, and a transition to a damaging wind
   threat may occur by evening.

   Higher quality moisture and instability will reside further south
   from the Arklatex toward the TN Valley vicinity. Convection will
   likely develop by late morning along the cold front in the Arklatex
   vicinity and spread eastward through period. Stronger large-scale
   ascent will be focused further north, but intense wind fields will
   still be across the broad warm sector. All hazards appear possible,
   with a mixed mode of supercells and linear convection.

   ...Days 5-6/Sat-Sun...

   The upper trough will continue east on Saturday, moving offshore the
   Atlantic coast by Sunday morning. Some severe potential could
   persist into the Mid-Atlantic and Southeast. Destabilization ahead
   of the eastward-advancing cold front likely will remain modest due
   to widespread cloudiness and precipitation early in the period.
   Lower amplitude flow will overspread much of the CONUS on Sunday and
   severe potential appears low.

   ...Days 7-8/Mon-Tue...

   Severe potential could once again increase early next week across
   parts of the Arklatex into the Mid/Lower MS and TN Valley vicinity.
   Another large-scale upper trough is expected to develop eastward
   across the western U.S. on Monday before moving into the central
   U.S. on Tuesday. However, guidance is vastly different in the timing
   of this system and how far north or south the trough will be
   located. While severe potential will likely accompany this system
   and probabilities will likely be needed in later outlooks,
   confidence in where the greatest threat will occur is low at this
   time.

   ..Leitman.. 03/28/2023

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