SPC AC 050600

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 AM CDT Mon Jun 05 2023

   Valid 061200Z - 071200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SIERRAS/GREAT BASIN...SOUTHERN HIGH PLAINS...AND NORTHEASTERN
   GEORGIA/SOUTH CAROLINA...

   ...SUMMARY...
   Isolated strong to severe thunderstorms may occur Tuesday across
   parts of the Sierras/Great Basin, southern High Plains, and
   northeastern Georgia into South Carolina.

   ...Synopsis...
   A stagnant upper-air pattern will persist over the CONUS on Tuesday,
   with an upper ridge centered over the northern Plains and central
   Canada. A closed upper low will remain over CA, with a separate
   upper trough/low across the eastern CONUS and Canadian Maritime
   provinces.

   ...Sierras/Great Basin...
   High-based thunderstorms should develop by early Tuesday afternoon
   across parts of the northern Sierras into the Great Basin as modest
   large-scale ascent attendant to a upper low over CA overspreads this
   area. Low-level moisture will remain quite limited, but diurnal
   mixing of the boundary layer and corresponding steepening of
   low-level lapse rates should encourage efficient convective
   downdraft momentum transfer to the surface. 25-35 kt of deep-layer
   shear should act to organize thunderstorms. Isolated severe wind
   gusts may occur with the more robust cores as they spread generally
   west-northwestward through the early evening. Occasional hail may
   also occur with the initially more discrete thunderstorms before
   clustering occurs.

   ...Southern High Plains...
   Limited low-level moisture will remain over the southern High Plains
   on Tuesday. Even with this region beneath mid-level ridging, most
   guidance still suggests that at least isolated convection will
   develop Tuesday afternoon along the higher terrain of
   central/eastern NM and west TX. Around 20-30 kt of effective bulk
   shear is forecast, mainly owing to modestly strengthening flow at
   mid/upper levels. While this shear appears marginal for organized
   convection, occasional instances of hail may occur with initial
   robust cores, as steep mid-level lapse rates should be present. Some
   upscale growth into loosely organized clusters will be possible by
   early evening. With steepened low-level lapse rates from daytime
   heating, isolated strong to severe wind gusts may occur before
   thunderstorms eventually weaken with eastward extent.

   ...South Carolina/Georgia...
   Thunderstorms may form by Tuesday afternoon along or just ahead of a
   weak surface trough/front from northern GA into SC. This region will
   be on the southwestern fringe of stronger flow aloft associated with
   an upper low over the Northeast. Moderate instability is forecast to
   develop through the day along/south of the trough/front, but
   deep-layer shear should remain generally modest. Even so, any
   convection that can develop may be capable of producing isolated
   hail and damaging winds as it spreads east-southeastward to the
   Atlantic Coast through Tuesday evening. Poor low-level convergence
   and weak ascent aloft cast some uncertainty regarding overall
   thunderstorm coverage.

   ...Northeast...
   Weak instability may develop Tuesday in close proximity to the upper
   low over portions of the Northeast. Thunderstorms that form across
   parts of New England and move quickly east-southeastward could
   produce occasional strong/gusty winds. However, confidence in
   severe-caliber gusts remains too low to include any wind
   probabilities at this time.

   ...South Florida...
   Modestly enhanced mid-level west-southwesterly flow should be
   present over south FL on Tuesday in association with a sub-tropical
   jet. Even though large-scale ascent will remain nebulous, most
   guidance indicates that isolated to scattered thunderstorms should
   develop along various sea breezes Tuesday afternoon. Gusty winds and
   small hail may occur with the strongest updrafts.

   ..Gleason.. 06/05/2023

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