ZCZC SPCSWOMCD ALL ACUS11 KWNS 211851 SPC MCD 211851 COZ000-WYZ000-212045- Mesoscale Discussion 1826 NWS Storm Prediction Center Norman OK 0151 PM CDT Wed Aug 21 2019 Areas affected...The Colorado front range to portions of southeast Wyoming Concerning...Severe potential...Watch possible Valid 211851Z - 212045Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorms will develop/intensify through early afternoon and pose a threat for severe hail and brief severe wind gusts. The potential coverage of the threat, and hence the need for a Severe Thunderstorm Watch, is uncertain. DISCUSSION...Strong heating and an approaching weak mid-upper-level low are contributing to deepening cumulus and initial thunderstorm development over the Colorado and Wyoming high terrain. A moist and modifying continental polar air mass has pushed up to the foothills, creating an environment supportive of thunderstorms that varies little with latitude from the Raton Mesa northward to the Laramie Mountains. By early afternoon, forecast soundings suggest this environment will consist of 1500-2500 J/kg of MLCAPE (higher toward the Mountains) with little convective inhibition, moderate straight-line vertical wind shear confined mostly in the 1-4 km layer (supportive of multicell to some transient supercell structures), and DCAPE of 1200-1500 J/kg. Given storm rotation and steep low-to-mid level lapse rates, severe hail is the main threat with these storms, but brief severe wind gusts are possible in the stronger downdrafts. Moderate low-level southeasterly upslope flow combined with relatively weak west-northwesterly to westerly flow at 500-300 mb suggests a slow south to southeast motion to the cells, thus limiting the eastward extent of the threat. The main uncertainty concerning the need for a Severe Thunderstorm Watch is the coverage of the hail/wind threat. The coverage of storms that mature and move into the foothills will be monitored in the next hour or so to better determine if a Watch will be needed. ..Coniglio/Guyer.. 08/21/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PUB...BOU...CYS...RIW... LAT...LON 42860625 42760567 41960518 40150447 39820440 38480387 37790355 37460341 37110354 37050408 37090466 37430506 38260552 39540598 40280617 41270651 42560648 42860625 NNNN