ZCZC SPCSWOMCD ALL ACUS11 KWNS 110128 SPC MCD 110128 SDZ000-NEZ000-110300- Mesoscale Discussion 0913 NWS Storm Prediction Center Norman OK 0828 PM CDT Thu Jun 10 2021 Areas affected...Western/central SD/NE Concerning...Severe potential...Watch likely Valid 110128Z - 110300Z Probability of Watch Issuance...95 percent SUMMARY...A rapid increase in thunderstorm coverage is expected near and after 02Z. One or more clusters capable of significant damaging wind will be possible, along with some threat for hail and possibly a tornado or two. Watch issuance is likely. DISCUSSION...Despite the presence of favorable instability and shear noted in regional 00Z soundings, thunderstorm development has thus far been suppressed across western SD/NE, likely due lingering MLCINH and midlevel subsidence noted on WV imagery. However, the subsidence zone is shifting eastward with time, and convection across eastern WY has recently intensified as ascent from an upstream shortwave trough begins to overspread the region. Meanwhile, a cold front is accelerating eastward toward the region, with very strong post-frontal winds noted across portions of southern MT and northern WY. As ascent continues to overspread the region, the front begins to catch up with the dryline, and the low-level jet begins to increase, a substantial increase in storm coverage is expected near and after 02Z from far eastern WY into western SD/NE. Even though MLCINH will be increasing with time, steep midlevel lapse rates will support vigorous convection near and just behind the front later tonight, with some potential for a surface-based supercell or two into the late evening. Any surface-based storm would be capable of very large hail and possibly a tornado. Later tonight, one or more organized clusters are expected to develop and move quickly eastward, with large DCAPE supporting the potential for swaths of damaging wind even as convection becomes increasingly elevated with time. Watch issuance is likely by 02Z in order to cover these threats. ..Dean/Dial.. 06/11/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...ABR...LBF...UNR...CYS... LAT...LON 41600400 44670387 45830380 45870212 45880083 45550030 44629970 43789937 42979926 42199956 41679998 41410092 41340215 41350291 41600400 NNNN