Storm Prediction Center Mesoscale Discussion 276

   Mesoscale Discussion 0276
   NWS Storm Prediction Center Norman OK
   0154 PM CDT Thu Mar 21 2024

   Areas affected...Parts of north and central Texas

   Concerning...Severe potential...Watch unlikely 

   Valid 211854Z - 212130Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Strong to severe thunderstorm development is expected over
   the next couple hours. Isolated large hail and locally severe gusts
   are the primary concerns. A watch is not currently expected.

   DISCUSSION...Boundary-layer cumulus is gradually deepening in the
   vicinity of a mesoscale low over northwest TX, where steep low-level
   lapse rates are impinging on middle/upper 50s surface dewpoints.
   Isolated convective initiation is underway in this area of focused
   mesoscale ascent. Farther south, cumulus is more shallow along the
   dryline (owing to weak low-level convergence), though deepening
   cumulus is developing west of the dryline in a
   well-mixed/destabilizing boundary layer. Aided by gradually
   strengthening DCVA preceding a midlevel shortwave trough crossing
   west TX, initial thunderstorms will develop/intensify along/south of
   the mesoscale low, where low-level convergence is maximized. Around
   35 kt of effective shear (characterized by a mostly straight
   hodograph) will support initially discrete cells, with an isolated
   hail risk (potentially up to 1.5 inches with the stronger storms)
   and locally strong/severe gusts. Farther south, thunderstorms should
   evolve out of the steep low-level lapse rate plume, with a similar
   risk of isolated hail and slightly greater severe-wind risk, given
   the steeper low-level lapse rates and stronger deep-layer shear.

   With time, these storms should increase in coverage and spread
   eastward, as the large-scale ascent continues to overspread the
   region. This will promote localized upscale growth into several
   loosely organized clusters, though the strongest deep-layer shear
   may be displaced to the south of this activity -- potentially
   limiting convective organization and favoring outflow dominant
   storms. Nevertheless, strong to severe gusts (generally 50-60 mph)
   will become the main concern, though isolated large hail will remain
   possible with the more discrete activity. Current thinking is that
   the severe hail/wind risk may remain too isolated/marginal for a
   watch, though convective trends will be monitored through the
   afternoon.

   ..Weinman/Goss.. 03/21/2024

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...FWD...OUN...EWX...SJT...LUB...

   LAT...LON   29909915 29939967 30149991 30600021 31770040 32650038
               33380016 33839983 34029939 34089897 34029836 33799780
               33399747 32239759 30449798 29959857 29909915