Storm Prediction Center Mesoscale Discussion 1328

   Mesoscale Discussion 1328
   NWS Storm Prediction Center Norman OK
   0556 AM CDT Tue Jun 17 2025

   Areas affected...parts of northeastern Colorado

   Concerning...Severe Thunderstorm Watch 427...

   Valid 171056Z - 171200Z

   The severe weather threat for Severe Thunderstorm Watch 427
   continues.

   SUMMARY...Intensities may be in the process of waning, with
   thunderstorm activity likely to end across the Front Range and shift
   across northeastern Colorado into southwestern Nebraska through 6-8
   AM MDT.  A new watch is not anticipated.

   DISCUSSION...Despite persistent northeasterly to north-northwesterly
   low-level flow south of the Cheyenne Ridge into the Palmer Divide,
   the boundary layer east of the Front Range near the Greater Denver
   vicinity has remained sufficiently moist to contribute to moderate
   instability beneath steep mid-level lapse rates overnight.  This was
   aided by mid-level cooling associated with a shorter wavelength
   perturbation preceding larger-scale mid-level troughing shifting
   east of the Great Basin, which contributed to the initiation of
   scattered strong thunderstorm development a couple of hours ago.  In
   the presence of modest shear this was sufficient to support severe
   hail in the stronger cores, but a notable diminishing trend may
   already be underway, based on recent radar trends.  In general,
   thunderstorm activity is expected to shift away from the Front Range
   toward the high plains of southwestern Nebraska through 12-14Z, with
   the forcing for ascent.

   ..Kerr.. 06/17/2025

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

   ATTN...WFO...LBF...GLD...BOU...CYS...

   LAT...LON   40220477 40490406 41060385 41150297 40770141 40010137
               40070279 39580388 39560457 40220477 

   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN