ZCZC SPCSWOMCD ALL ACUS11 KWNS 061955 SPC MCD 061955 NEZ000-SDZ000-MTZ000-WYZ000-062200- Mesoscale Discussion 1054 NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Jun 06 2022 Areas affected...Southeast Montana and northeast Wyoming into southwest South Dakota and Northwest Nebraska Concerning...Severe potential...Watch likely Valid 061955Z - 062200Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms will continue to intensify through the remainder of the afternoon across the northern High Plains. One or more supercells may propagate southeast into northwest Nebraska through the evening hours. A watch will likely be needed to address this potential for more intense storms. DISCUSSION...GOES imagery and lightning data continue to point towards an uptick in convective activity across the northern High Plains. This is in response to 1) increasing destabilization via daytime warming and 2) increasing ascent associated with the left-exit region of an approaching upper-level jet. Additionally, more isolated thunderstorms are noted along a weak cold front draped from southeast MT into western SD/NE. This trend will continue through the rest of the afternoon as daytime warming continues and the upper jet noses into the northern Plains. Effective bulk shear values between 40-50 knots, combined with MLCAPE increasing to 1000-1500 J/kg, are favorable for robust convection. Splitting supercells, and perhaps one or two organized clusters, will most likely propagate to the southeast through the evening along the buoyancy gradient/cold frontal boundary. The favorable thermodynamic and kinematic environments and high likelihood of one or more discrete supercells will support a large hail threat (including the potential for significant hail). 8-9 C/km low-level lapse rates is favorable for severe winds, especially if an organized cluster can become established. A watch will likely be needed as convection continues to intensify. ..Moore/Mosier.. 06/06/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...UNR...CYS...BYZ...RIW... LAT...LON 44510630 45140631 45620541 45660452 44720346 43450143 42759999 42369929 41909866 41439875 41009922 40690011 40950123 41520232 41900291 44510630 NNNN