7PM Day 1 Convective Outlook for Tuesday, July 15. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN CENTRAL SD
SUMMARY
Strong to severe gusts over South Dakota should diminish into late evening. Isolated severe hail and wind remains possible overnight from parts of Montana to northern Minnesota.
Northern/central High Plains to northern MT
Much of the high-based convection from southwest SD to northeast CO should weaken in the next couple hours, with a waning severe-gust threat. More recent development into north-central SD may persist into late evening before diminishing near the northeast SD/southeast ND border as nocturnal MLCIN builds.
Elevated thunderstorms will develop in the late evening and become widespread overnight, especially across ND and northern MN, with strengthening large-scale ascent atop a well-defined surface front. Severe hail and strong gust coverage is expected to remain isolated. These hazards might be maximized in a mesoscale corridor across central/eastern ND into northern MN. But convective orientation nearly paralleling the effective bulk shear vector suggests a cluster mode should quickly dominate. This along with a minimal speed change in the mid to upper portion of the MUCAPE profile (as sampled by the 00Z BIS sounding) support maintaining level 1-MRGL risk.
Southeast AZ
Sparse convective coverage amid weak mid-level northeasterlies, as sampled by area VWP data, appears to be mitigating the severe wind threat. Locally strong gusts may still occur through dusk as isolated cells slowly spread west-southwest.