SPC AC 181604

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1004 AM CST Tue Jan 18 2022

   Valid 181630Z - 191200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   No severe thunderstorm areas are expected over the CONUS.

   ...Synopsis...
   Low-amplitude, split mid-level flow will dominate the flow pattern
   across the central and eastern US in the wake of the strong
   northeastern trough moving offshore today. A shortwave trough
   embedded within the strong northwesterly branch across the upper
   Midwest will drive an Arctic Front south across the northern Plains
   toward the Mississippi Valley late tonight. At the same time, a
   shortwave trough within the sub-tropical jet over northern Baja
   California is forecast to intensify as it moves east. 

   The southern stream shortwave trough evident in moisture-channel
   imagery across southern CA and southwestern AZ is forecast to move
   east today across portions of the Desert Southwest, reaching the
   southern High plains by early Wednesday. As it does so, modest
   mid-level height falls and DCVA will overspread a modifying surface
   airmass across eastern AZ and western NM. Steepening mid-level lapse
   rates and surface temperatures near 50 F, will provide just enough
   buoyancy for the development of isolated thunderstorms this
   afternoon/evening. Generally less than 250 J/kg, the meager MUCAPE 
   and relatively weak vertical shear suggests the threat for severe
   weather with any thunderstorms is very low. 

   Elsewhere across the CONUS, a dry post-frontal airmass will limit
   surface return moisture through much of the day, negating sufficient
   buoyancy for lightning.

   ..Lyons/Grams.. 01/18/2022

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