SPC AC 050545

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1245 AM CDT Sun Jun 05 2022

   Valid 051200Z - 061200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
   WESTERN/CENTRAL KANSAS INTO NORTHERN OKLAHOMA...

   ...SUMMARY...
   Significant severe weather may develop across the central Plains
   Sunday afternoon then spread into Oklahoma during the evening. Very
   large hail and damaging winds are expected. An upgrade to Moderate
   Risk may be warranted. Otherwise, isolated strong/severe storms are
   possible across the interior northwestern United States.

   ...Central Plains/Oklahoma...

   Early this morning a weak short-wave trough was located over eastern
   ID/UT. This feature is forecast to translate through the central
   Rockies ridge into the High Plains of NE/CO by 18z then turn
   southeast into central KS/western OK by 06/00z. While mid-level flow
   is not forecast to be particularly strong, latest NAM guidance
   suggests 30-40kt of 500mb flow will strengthen to near 60kt over
   northern OK by late evening, possibly influenced by convective
   feedback. Regardless, LLJ will respond to this feature and increase
   markedly by early evening along the I-35 corridor across OK/KS,
   perhaps intensifying in excess of 60kt by 06/06z over northern OK
   before veering into northwest AR by daybreak Monday. A reservoir of
   very strong instability will likely extend across western KS into
   central OK. However, one caveat that could disrupt this instability
   would be a deviant MCS storm motion after sunrise this morning. This
   will be addressed at 13z.

   A slow-moving MCS is currently propagating southeast across central
   KS. Boundary-layer disruption from this activity will prove highly
   influential in late-afternoon convective development/severe
   potential. Current thinking is the MCS should spread across central
   KS toward northeast OK and likely force a convective boundary to
   drape itself in a southeast-northwest oriented fashion along the
   western/southern flank of this complex. Strong boundary-layer
   heating across the central High Plains should easily remove CINH
   ahead of the short wave for thunderstorm development. This activity
   should grow upscale as it propagates southeast along/near the
   aforementioned MCS outflow. While supercells may be noted early in
   the convective cycle, a potentially significant MCS may evolve over
   KS and surge into northern OK during the evening. Early supercells
   could produce hail in excess of 2 inches while the maturing MCS
   could generate significant wind, possibly in excess of 75 miles per
   hour with any bow echoes. Large convective complex should spread
   toward northwest AR during the late night hours.

   ...Interior Northwest...

   Notable 500mb speed max is forecast to translate across northern CA
   into southeast OR by late afternoon. Strongly diffluent high-level
   flow, cooling mid-level temperatures, and steep lapse rates will
   encourage/support organized convection. Strengthening wind profiles
   may result in a few supercells that could generate isolated
   hail/wind.

   ..Darrow/Weinman.. 06/05/2022

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