ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 100929
   SPC AC 100929

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0329 AM CST Wed Mar 10 2021

   Valid 131200Z - 181200Z

   ...DISCUSSION...
   ...Saturday/Day 4 and Sunday/Day 5...
   An upper-level low is forecast to move across the Four Corners
   region on Saturday as a 75 to 90 Kt mid-level jet moves into the
   southern High Plains. At the surface, a low is forecast to rapidly
   deepen across southeast Colorado as moisture advection continues
   across the southern Plains. By afternoon, an axis of maximized
   low-level moisture should be located from north Texas into western
   Oklahoma and southern Kansas. The models show a corridor of
   instability by late afternoon along the western edge of the moist
   airmass. Thunderstorms are expected to develop within this corridor
   of instability and move eastward across northwest Texas, the far
   eastern Texas Panhandle and western Oklahoma during the late
   afternoon and early evening. Squall line development may take place
   during the evening, affecting north-central Texas and central
   Oklahoma. Eastern Oklahoma and parts of northeast Texas could be
   impacted during the overnight period. All hazards will be possible
   across the threat area.

   On Sunday, a disorganized line of storms may be ongoing in the
   southern Plains at the start of the period. As surface temperatures
   warm through the day, the line is expected to reorganize. Model
   consensus places this line over eastern Oklahoma and northeast Texas
   around midday. The squall-line is forecast to move across the
   southern Ozarks and Arklatex regions during the afternoon. Surface
   dewpoints ahead of the squall-line are forecast to be near 60 F.
   This combined with strong deep-layer shear and enhanced large-scale
   ascent will likely be favorable for severe storms. Although all
   three severe hazards will be possible, the wind damage threat may be
   the greatest of the three.

   ...Monday/Day 6 to Wednesday/Day 8...
   Model solutions diverge sharply on Monday. Some models weaken the
   central U.S upper-level low while others continue to move the system
   eastward. The models also differ on the surface pattern, with some
   solutions keeping a moist airmass located from the central Gulf
   Coast states into the Tennessee Valley. If the more aggressive
   solutions are reasonably close to verifying, then a severe threat
   would be possible near the moist axis Monday afternoon, from middle
   and eastern Tennessee southward into Mississippi and Alabama.

   The large spread among solutions continues into Tuesday and
   Wednesday. The most aggressive solutions develop an upper-level low
   in the central states on Tuesday and move the system
   north-northeastward into the upper Mississippi Valley on Wednesday.
   Under this scenario, a severe threat would be possible in the
   Arklatex on Tuesday afternoon and evening. On Wednesday, a severe
   threat would be possible further to the east in the Ohio and
   Tennessee Valleys. However, uncertainty is high toward the end of
   the Day 4 to 8 period.

   ..Broyles.. 03/10/2021

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