Mesoscale Discussion 1176
   NWS Storm Prediction Center Norman OK
   1256 PM CDT Fri Jun 21 2019

   Areas affected...Central/Eastern Colorado

   Concerning...Severe potential...Watch possible 

   Valid 211756Z - 211930Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Easterly upslope flow/moisture advection and diabatic
   heating contributing to destabilization. A watch may be needed in
   the next 1-2 hours.

   DISCUSSION...Regional surface observations show continued moistening
   of the boundary layer along and east of the Front Range due in large
   part to low-level easterly upslope flow. Currently, dew point
   temperatures are in the mid to upper 40s F in proximity to the
   Denver Metro area. Despite meager instability currently (MLCAPE
   400-500 J/kg), low-level flow trajectories suggest a continuation
   moistening/destabilization throughout the afternoon, with dew points
   in the 50s to near 60 F residing in eastern/southeastern Colorado.
   Consequently, diabatic heating has lead to the development of a band
   of cumulus in this region.

   As the aforementioned processes continue to unfold, a few storms
   should develop along the Front Range, particularly over the high
   terrain areas, and propagate eastward with time. Forecast soundings
   from the RAP/HRRR indicate pronounced deep-layer shear (50-60 kt
   effective shear), given enhanced west-southwesterly mid-level 50+ kt
   flow and turning of the winds with height. Convection should
   organize into multicellular/supercellular structures and
   progressively intensify as they encounter richer boundary-layer
   moisture to the east. Forecast soundings also show steep low-level
   lapse rates (7-8 C/km) indicating the potential for strong/gusty
   outflow winds, along with a severe hail threat. A watch may be
   needed in the next 1-2 hours in anticipation of these convective
   trends.

   ..Karstens/Hart.. 06/21/2019

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

   ATTN...WFO...PUB...BOU...

   LAT...LON   39240503 39960527 40270502 40030363 39720322 39240327
               38280379 38210466 38570496 39240503