Storm Prediction Center Mesoscale Discussion 1558

   Mesoscale Discussion 1558
   NWS Storm Prediction Center Norman OK
   0239 PM CDT Thu Jul 09 2026

   Areas affected...portions of the central High Plains

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 091939Z - 092145Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Developing thunderstorms will evolve eastward off of the
   high-terrain of southeastern Wyoming and central Colorado this
   afternoon and evening, bringing a risk for damaging/severe wind
   gusts and large hail.

   DISCUSSION...Aided by forcing for ascent ahead of a subtle mid-level
   perturbation and southeasterly upslope flow, ongoing thunderstorm
   development across the central Rockies and Laramie Range is expected
   to increase in coverage through the afternoon, with deep-layer
   westerly flow aloft yielding an eastward progression of developing
   convection. Steepening low-level lapse rates and dry, well-mixed
   boundary layer profiles will favor efficient evaporative cooling and
   an amalgamation of cold pools, with gradual upscale growth into one
   or more linear clusters/segments and an increase in the threat for
   damaging/severe wind gusts expected into this evening. Given the
   presence of a surface moisture gradient (dewpoints in the 40s to low
   50s F near the Foothills increasing into the low-to-mid 60s in
   western Kansas/Nebraska) and only modest effective shear of 25-30
   kts, storm organization/intensification may occur relatively slowly
   as storms progress eastward. Thus, while one or more Severe
   Thunderstorm Watches will likely be needed later this
   afternoon/evening, the timing of watch issuance remains uncertain
   pending the increase in storm organization and the attendant severe
   risk.

   ..Chalmers/Hart.. 07/09/2026

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

   ATTN...WFO...LBF...DDC...GLD...PUB...BOU...CYS...

   LAT...LON   39180410 40700425 42160414 42730402 42910373 42930311
               42750250 42290224 41400200 39880187 38730188 37970200
               37450216 37210240 37140266 37260304 38080374 39180410 

   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN