SPC AC 011650

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1150 AM CDT Sat Jun 01 2024

   Valid 011630Z - 021200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHWEST
   KANSAS INTO THE TEXAS AND OKLAHOMA PANHANDLES AND NORTHWEST
   OKLAHOMA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE CENTRAL
   AND SOUTHERN HIGH PLAINS AND PORTIONS OF THE MIDDLE AND UPPER TEXAS
   COAST INTO SOUTHWEST LOUISIANA...

   ...SUMMARY...
   Scattered severe storms, including a few supercells, are expected to
   develop across the central and southern High Plains region,
   including portions of the Big Bend of Texas, this afternoon. This
   activity should evolve into organized clusters while spreading into
   the adjacent Great Plains later in the evening. Severe wind, hail,
   and perhaps a couple of brief tornadoes are the expected risks.

   ...Central and southern High Plains through tonight...
   Morning surface analysis places a surface front draped across NE,
   with weak lee troughing farther to the south across eastern CO/NM in
   response to modest westerly midlevel flow.  Residual outflow
   boundary intersects the lee trough/dryline over western NE. 
   Scattered thunderstorms are expected to form by mid afternoon along
   the surface boundaries and immediately east of the higher terrain,
   and then move eastward/southeastward onto the Plains through
   tonight.

   A few supercells may also form across eastern CO into western NE,
   where large hail up to 2-2.5 inches in diameter will be possible. 
   Recent model guidance has shown stronger agreement in showing
   scattered thunderstorms developing from southeast CO into western KS
   late this afternoon into the evening.  Upscale growth into an MCS is
   progged by model guidance within an environment characterized as
   moderately unstable and featuring steep low to mid-level lapse
   rates, and moderately strong deep flow supporting organized storms. 
   An intensification of low-level southerly flow during the evening
   will promote additional storms/mergers into a severe cluster moving
   east-southeast into parts of the TX Panhandle/northwest OK during
   the evening.  Large hail will be possible with the initial storms,
   but the threat should evolve more to severe outflow winds of 60-80
   mph with the upscale growth.

   Farther south, the environment across southwest TX will favor
   splitting supercells immediately east of the mountains, where
   long/straight hodographs (with effective bulk shear 40-50 kt), steep
   midlevel lapse rates and MLCAPE near 3000 J/kg will support very
   large hail of baseball size (2.75 inches) or larger.  Isolated
   severe outflow gusts will also be possible.  

   ...South central/southeast TX into southwest LA this afternoon...
   Scattered thunderstorm development is expected this afternoon along
   a stalled front extending from south central TX into southwest LA. 
   The boundary layer continues to destabilize (strong buoyancy as of
   midday) with moderately strong westerly flow above 500 mb.  A mix of
   multicell clusters and, perhaps, some weak supercell structures will
   be possible, with the potential to produce isolated large hail and
   wind damage.  

   ...MS/AL/TN area today...
   A midlevel trough over the middle and lower MS Valley will move
   slowly eastward to the TN/OH Valleys through tonight.  A couple of
   different storm clusters will be possible this afternoon near and
   just east of the midlevel trough within the surface warm sector
   across MS/AL/TN.  Deep-layer vertical shear is relatively weak per
   regional VWPs, but there is some low-level hodograph curvature
   within a warm advection regime.  Given weak-moderate buoyancy where
   boundary-layer dewpoints are in the upper 60s or greater, and later
   pockets of surface heating in cloud breaks, a few storm clusters may
   include embedded, weakly rotating storms capable of producing a
   brief tornado or two, along with isolated wind damage.

   ...Northern UT...
   Isolated to widely scattered high-based convection is forecast to
   develop this afternoon.  Ample mid- to high-level flow will aid in
   some organization.  The very steep lapse rates (inverted-v profiles)
   will favor evaporative cooling with the stronger cores and the
   potential for isolated severe gusts.

   ..Smith/Weinman.. 06/01/2024

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