ZCZC SPCSWOMCD ALL ACUS11 KWNS 032321 SPC MCD 032321 SDZ000-NDZ000-WYZ000-040115- Mesoscale Discussion 1637 NWS Storm Prediction Center Norman OK 0621 PM CDT Sat Aug 03 2019 Areas affected...Southwest ND...Western SD...Northeast WY Concerning...Severe potential...Watch unlikely Valid 032321Z - 040115Z Probability of Watch Issuance...20 percent SUMMARY...Isolated supercells capable of large hail and localized severe wind gusts will remain possible into mid evening before weakening. Watch issuance is unlikely due to limited coverage and duration of the threat. DISCUSSION...Widely scattered strong thunderstorms are ongoing across portions of the northern High Plains at 2315Z, with the strongest storm across southwest ND displaying supercell characteristics. Moderate instability (MLCAPE of 1500-2000 J/kg) and sufficient effective shear (40-50 kt) will support the potential for supercell structures with ongoing convection in the short term, though storms are expected to remain widely scattered given limited large-scale ascent across the region. Large hail and locally severe wind gusts will be the primary threats. Increasing MLCINH with eastward extent will limit the potential for supercells to spread very far downstream, though cells that develop more rightward motion (like the cell in southwest ND) will have a longer residence time within a weakly capped environment and have greater potential to persist for another 1-2 hours across western SD. An eventual weakening trend for any remaining cells is expected later this evening in conjunction with diurnal cooling/stabilization. Due to the limited coverage and duration of the severe threat, watch issuance is unlikely. ..Dean/Thompson.. 08/03/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...UNR... LAT...LON 44070515 44950384 45910374 46750342 46700267 46150234 45180250 44360284 43860300 43610430 44070515 NNNN