SPC AC 010750

   Day 1 Convective Outlook RESENT 1
   NWS Storm Prediction Center Norman OK
   0150 AM CST Sat Jan 01 2022

   Valid 011200Z - 021200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PORTIONS
   OF THE LOWER MISSISSIPPI VALLEY TO THE TENNESSEE VALLEY...

   ...SUMMARY...
   Widespread thunderstorms are expected from the ArkLaTex to the
   Western Appalachians today. All severe-weather hazards are possible
   in parts of these areas, including large hail, damaging winds, and
   tornadoes.  Strong tornadoes are possible.

   ...Northeast TX to Western Appalachians...

   Late-evening water-vapor imagery depicts a well-defined upper
   vort/short-wave trough along the southeast AZ/NM border, shifting
   northeast in line with latest model guidance. Dominant upper ridging
   over the southeastern US will move little during the day1 period
   which will force this short wave across MO into the OH Valley where
   it will deamplify within the broader, strong southwesterly flow
   regime. Resultant mid-level height falls are not forecast to be that
   strong across the warm sector which will encourage the most
   concentrated convection to congregate along/near the frontal zone.
   Additionally, weak surface low is forecast to track northeast along
   the wind shift in response to the ejecting short wave from AR at
   daybreak to WV by 02/00z.

   Low-level warm advection is currently (0530z) aiding a corridor of
   maturing thunderstorms from north-central TX-southeast OK-northern
   AR. This activity will likely prove to be the western-northern edge
   of strong/severe convection at the start of the period. 00z
   soundings across the warm sector were considerably capped this
   evening and forecast soundings across portions of the warm sector
   later today continue to suggest a relative warm layer near 700mb
   which is expected to limit lapse rates through this layer. It's not
   entirely clear how much discrete warm sector development will occur
   at lower latitudes but wind profiles/low-level shear certainly favor
   supercells and tornadoes, and potentially a strong tornado or two.
   Higher confidence in thunderstorm coverage exists with frontal
   convection. Storm mode will be considerably messy with line segments
   and clusters along/near the wind shift. Even a few embedded
   supercells can be expected given the observed strong wind fields.
   01/00z NAM suggests 65kt LLJ will translate ahead of the short wave
   from northern MS/southern AR early, across MS/western TN by 18z,
   then into eastern KY by early evening. This reflects the stronger
   forcing and likely the primary corridor for more concentrated
   strong/severe thunderstorms. Damaging winds and tornadoes are the
   primary risks, though some hail may be noted across western/central
   portions of the outlook.

   ..Darrow/Lyons.. 01/01/2022

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