Mesoscale Discussion 1985 NWS Storm Prediction Center Norman OK 0400 PM CDT Sat Aug 24 2024 Areas affected...parts of northeastern Montana Concerning...Severe potential...Watch unlikely Valid 242100Z - 242330Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorm activity may begin to initiate, with the evolution of an isolated supercell possible, by 4-5 PM MDT. This may pose a risk for large hail, locally damaging wind gusts, and perhaps some potential for a brief tornado. DISCUSSION...Low-level convergence appears to be locally strengthening within weak surface troughing near the Wolf Point vicinity, where surface dew points remain in the lower/mid 60s F, as temperatures warm into the 90s F. Inhibition is gradually eroding with continuing insolation, and this may be aided by weak mid-level cooling through late afternoon, downstream of a mid-level perturbation progressing across and northeast of the Canadian Rockies. Initial attempts at deepening convective development appear slowly underway, in the presence of thermodynamic profiles already characterized by steep lower/mid-tropospheric lapse rates and CAPE in excess of 2000 J/kg. Beneath 35-60+ kt south-southwesterly flow in the 500-300 mb layer, deep-layer shear is already strong and conditionally supportive of supercells. Although the strength of mid/upper forcing for ascent remains a bit unclear, the High Resolution Rapid Refresh and Rapid Refresh, in particular, suggest that at least isolated thunderstorms may initiate as early as 22-23Z. Once this occurs, intensification may be fairly rapid, with storms becoming capable of producing large hail, locally damaging gusts gusts, and perhaps some risk for a brief tornado, despite generally small/linear low-level hodographs. ..Kerr/Guyer.. 08/24/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GGW... LAT...LON 49550459 48250422 47870592 48790686 49660673 49550459
Storm Prediction Center Mesoscale Discussion 1985
24
Aug