Mesoscale Discussion 1577
   NWS Storm Prediction Center Norman OK
   0825 PM CDT Mon Jul 22 2019

   Areas affected...Southern Arizona

   Concerning...Severe Thunderstorm Watch 539...

   Valid 230125Z - 230300Z

   The severe weather threat for Severe Thunderstorm Watch 539
   continues.

   SUMMARY...Numerous strong to severe storms are moving westward in
   severe thunderstorm watch 539.

   DISCUSSION...Several storms and outflow boundaries have developed
   and are moving north, south, and west toward eastern Pinal county.
   The very steep low-level lapse rates (8+ C/km per PHX and TUS 00Z
   RAOB) suggest these storms will pose a threat for severe downdraft
   winds. Storm/outflow boundary mergers in this area may lead to
   additional storm development and clustering which could lead to an
   increased risk for severe wind gusts in this area in the next 1 to 2
   hours. Any storm cluster/outflow that develops from this expected
   storm interaction may pose a threat for severe wind gusts and
   blowing dust possibly as far west as the Phoenix metro area.

   ..Bentley.. 07/23/2019

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

   ATTN...WFO...TWC...FGZ...PSR...

   LAT...LON   31711252 32481308 33651276 33961236 33941104 33711042
               33261017 32380982 31730982 31451010 31271027 31271115
               31711252