SPC AC 210737

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0237 AM CDT Tue Jun 21 2022

   Valid 231200Z - 241200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE NORTHERN HIGH PLAINS...CENTRAL PLAINS...AND UPPER MIDWEST...

   ...SUMMARY...
   Isolated severe thunderstorms are possible across northern High
   Plains, the central Plains, and Upper Midwest on Thursday.

   ...Central Plains...
   Upper ridging is forecast to be centered over the southern Plains
   early Thursday morning. This upper ridge, which will extend across
   much of the southern third of the CONUS, is expected to remain
   largely in place throughout the period. A subtle shortwave trough
   will likely traverse the northern periphery of this upper ridge,
   moving from the central Rockies eastward across the central Plains
   throughout the period. An associated surface low should move
   eastward just ahead of this shortwave. Ascent attendant to the
   shortwave combined low-level convergence in the vicinity of this
   surface low and strong buoyancy will likely result thunderstorm
   development. Upper flow will be modest, but veering wind profiles
   should still result in enough vertical shear for storm organization
   and a few strong to severe storms. Subtle character of the shortwave
   and timing difference within the guidance introduce some uncertainty
   regarding storm coverage and the most probable location for
   development. This uncertainty merits keeping severe probabilities at
   5% for this outlook.  

   ...Northern High Plains...
   Given the presence of the expansive upper ridging over the southern
   CONUS, any stronger westerly flow aloft will be displaced north to
   the international border vicinity. A shortwave trough embedded
   within this stronger flow is forecast to move from British Columbia
   into Saskatchewan. Enhanced southwesterly flow throughout the base
   of this shortwave should expand across the northern Rockies. Modest
   large-scale ascent and increasing mid-level moisture coincident with
   this increasing mid-level flow could support a few strong
   thunderstorms capable of damaging wind gusts. 

   ...Eastern Dakotas/Upper Midwest...
   Strong buoyancy is expected to develop Thursday afternoon as a
   result of ample low-level moisture, strong daytime heating, and
   relatively cool temperatures aloft. A weak surface boundary may be
   exist over the region, with convergence along the boundary just
   enough to produce isolated thunderstorms. Given the robust buoyancy,
   a few strong updrafts capable of damaging wind gust and/or hail are
   possible.

   ..Mosier.. 06/21/2022

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z