SPC AC 301734

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1234 PM CDT Tue Apr 30 2024

   Valid 011200Z - 021200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN A PART OF
   SOUTHWEST KS TO NORTHWEST OK...

   ...SUMMARY...
   Scattered severe thunderstorms are possible across parts of the
   central and southern Great Plains from Wednesday afternoon into
   Wednesday night. A few tornadoes, very large hail, and damaging
   winds are anticipated.

   ...Synopsis...
   In the wake of a vigorous shortwave trough moving across the Upper
   Great Lakes to the Saint Lawrence Valley, an upstream shortwave
   impulse will gradually shift east from the northern Rockies to the
   northern High Plains. The initial cold front on D1 over the central
   Great Plains will stall and advance north as a warm front Wednesday
   night. Convective outflows from residual D1/early D2 convection
   should exist south of this boundary in parts of OK. 

   ...Central Great Plains...
   Consensus of guidance continues to trend south with the placement of
   the quasi-stationary front expected to be lying across southern KS
   at 12Z Wednesday. A pronounced low-level jet should restrengthen
   during the day, which will probably yield a swath of elevated
   convection spreading northeast across the Mid-MO Valley with perhaps
   a marginal severe hail threat. How far north the front will advance
   during the day is uncertain with above-average spread across
   guidance, but near its intersection with the surface dryline in the
   southwest to west-central KS vicinity should be the most favorable
   combination of the thermodynamic/kinematic environment. With
   near-neutral mid-level height change through early evening,
   convergence along the dryline will be necessary for late afternoon
   thunderstorm development. Guidance largely suggests convective
   coverage will remain isolated at most. But within a highly favorable
   environment for supercells, tornadoes and very large hail will be
   possible. 

   On Wednesday evening into the night, the plume of returning
   low-level moisture coupled with increasing large-scale ascent
   downstream of the northern Rockies to High Plains should lead to
   largely elevated storms developing in the CO/NE/KS border vicinity.
   Much of this convection should remain north-northwest of the surface
   warm front and likely remain elevated until very late in the period.
   But with very steep lapse rates aloft, a strong low-level jet and
   strong forcing for ascent, an elevated MCS capable of producing both
   large hail and severe surface wind gusts remains possible. 

   ...Southern Great Plains...
   Strong heating will occur near the dryline, where an uncapped and
   very unstable air mass will develop with MLCAPE of 3000-3500 J/kg.
   Bulk of guidance suggests appreciable convective development will
   occur in west TX, where a minor mid-level impulse may emerge within
   the modest southern-stream flow regime. More isolated dryline storms
   should form farther north, perhaps intersecting with residual
   outflows from remnant convection in OK on Wednesday morning. 

   Deep-layer shear compared to early May climo will be relatively
   modest, but the ample buoyancy coupled with numerous storms should
   yield a mixed cluster and transient/slow-moving supercell mode.
   Large to significant severe hail and sporadic severe wind gusts will
   be possible. Potential will exist for upscale growth into
   slow-moving clusters that move east into central parts of TX during
   the evening and likely linger overnight, with a gradually subsiding
   severe threat during these time frames.

   ..Grams.. 04/30/2024

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