SPC AC 241629

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1129 AM CDT Mon May 24 2021

   Valid 241630Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
   PLAINS AND SOUTHERN HIGH PLAINS...

   ...SUMMARY...
   Scattered severe thunderstorms are possible, mainly from
   mid-afternoon through evening, over parts of the central Plains into
   the southern High Plains, with other strong to severe storms
   possible across the Mid-Atlantic States.

   ...Central Plains to southern Minnesota/northern Iowa...
   A southwest/northeast-oriented front has generally stalled across
   the region, with low/some middle 60s F surface dewpoints near and
   southeast of this front. A northeastward-moving shortwave
   trough/speed max will at least glancingly influence the frontal zone
   by around peak heating. Front aside, a lingering outflow
   boundary/zone of differential heating to the northeast of a
   southeast Colorado surface low and near/southeast of the synoptic
   front may be a particular focus for intense storm development later
   this afternoon across western Kansas. 

   Sufficient deep-layer shear will exist in vicinity of the
   front/outflow to support a mixed mode of multicell clusters and
   supercells as storms develop during the mid to late afternoon. Large
   hail/damaging winds will be possible, and some tornado potential
   will also exist, particularly in vicinity of the western Kansas
   boundary late this afternoon/early evening. As the low-level jet
   increases this evening, modest upscale-type storm organization may
   occur across western toward west-central/north-central Kansas, while
   additional late-night development is also plausible from far eastern
   Colorado into northern Kansas/far southern Nebraska, with at least
   some continued potential for locally severe hail/wind.

   ...Southern High Plains...
   Scattered thunderstorms will likely develop across the higher
   terrain of the Texas Trans-Pecos and along the front/dryline from
   southeast New Mexico into the western Oklahoma/Texas Panhandles late
   this afternoon. Semi-steep mid-level lapse rates atop the western
   periphery of upper 50s/low 60s F surface dewpoints will support
   upwards of 1500-2500 J/kg MLCAPE by peak heating.
   Low/mid-tropospheric winds will be relatively weak (20 kt or less)
   but ample instability will support some intense multicells,
   including the possibility of upscale quasi-linear growth through
   early/mid evening across the west/northwest Texas Plains and
   southern Texas Panhandle. A combination of large hail and
   severe-caliber winds can be expected.

   ...Central Virginia/eastern West Virginia to North Carolina...
   A west/southwestward-moving backdoor cold front will influence the
   region with a moist (60s F surface dewpoints) and moderately
   unstable environment along and west/south of the front this
   afternoon. Influenced by a subtle southeastward-moving mid-level
   disturbance, initial thunderstorm development/intensification is
   most probable this afternoon along the West Virginia/Virginia border
   region and Blue Ridge vicinity, with storms subsequently spreading
   generally southward into other parts of southern Virginia and
   northern North Carolina through late afternoon and early evening. As
   much as 30 kt of effective shear, maximized in the immediate
   vicinity of the front, and a warm/well-mixed boundary layer will
   support the possibility of isolated damaging wind gusts.

   ...Northern Wisconsin...
   The region will be influenced by steady height falls and
   strengthening southwesterly winds aloft in advance of the upper
   trough centered over the Canadian Prairies and northern High
   Plains/Dakotas. A warm front will continue to spread northward
   across the northern half of Wisconsin toward the Upper Peninsula of
   Michigan. A regional maximization of modest destabilization and
   somewhat stronger deep-layer/low-level shear should occur across
   northwest Wisconsin in vicinity of the warm front, where some
   transient supercells will be possible late this afternoon and early
   evening.

   ..Guyer/Bunting.. 05/24/2021

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