Mesoscale Discussion 1314
   NWS Storm Prediction Center Norman OK
   0133 PM CDT Wed Jul 22 2020

   Areas affected...portions of the western Great Basin

   Concerning...Severe potential...Watch unlikely 

   Valid 221833Z - 222030Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Scattered thunderstorm development is expected by the mid
   afternoon hours, and will pose an isolated risk for strong downburst
   winds and perhaps severe hail.

   DISCUSSION...Recent GOES visible and IR imagery across the western
   Great Basin show deepening cumulus with cooling cloud top
   temperatures developing off of higher terrain across eastern NV as
   well as within a broad deformation zone ahead of an approaching
   upper-level low off the CA coast. A few transient lightning strikes
   have also been noted over the past hour. While sustained convection
   has yet to develop, these trends suggest that more robust convective
   initiation is probable in the next 1-2 hours. Elevated instability
   remains somewhat marginal (widespread MUCAPE values near 500 J/kg),
   but low-level lapse rates have already steepened to 8-9 C/km across
   a broad region as a result of deep boundary-layer mixing. 

   Once convection becomes established, a gradual increase in storm
   intensity is expected through the late afternoon hours as continued
   boundary-layer warming, coupled with the steep mid-level lapse rates
   noted in morning soundings, helps augment instability. Additionally,
   the approach of stronger flow aloft associated with the upper-level
   wave will help strengthen deep layer shear through the afternoon.
   The aforementioned steep low-level lapse rates will support the
   potential for sporadic strong to severe downburst winds. A few
   instances of severe hail will be possible with any stronger, more
   organized storm, but widespread severe convection does not appear
   likely and precludes the need for a watch.

   ..Hart/Moore.. 07/22/2020

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

   ATTN...WFO...BOI...LKN...REV...MFR...STO...

   LAT...LON   39921770 40191866 40302023 40292108 40912140 41472089
               41992003 42311903 42311769 42351689 41731478 40711426
               39041435 39231540 39521662 39921770