Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Wed Oct 01 2025 Valid 041200Z - 091200Z ...DISCUSSION... Downstream of a building mid-level ridge, and perhaps evolving embedded high over the northeastern Pacific, it appears that large-scale troughing will be maintained across the Great Basin/Southwest vicinity through this coming weekend and beyond. However, an initially notable short wave trough, digging into the Great Basin by late this week, is forecast to accelerate across and northeast of the Rockies, through northern Ontario, Saturday into early next Monday morning. The extent to which it maintains strength as it eventually consolidates into mid-level troughing shifting across and east of the Canadian Prairies, remains unclear. But, latest medium-range output appears to be trending deeper with developing surface troughing, and perhaps a relatively compact evolving surface cyclone, northeast of the Front Range through the northern Great Plains/Upper Midwest vicinity. Preceded by a northeastward advecting plume of elevated mixed-layer air, strengthening flow and shear could contribute to potential for organized severe convection across parts of western/central Nebraska through the eastern Dakotas/western Minnesota late Saturday into Saturday evening, and perhaps farther east across the Upper Midwest/adjacent Great Lakes vicinity on Sunday. However, this threat still appears largely conditional. It will probably take greater boundary-layer moistening than is currently suggested possible by the medium-range output to support more than relatively minor severe weather potential in the form of a few strong gusts, in the presence of thermodynamic profiles characterized by a deeply mixed boundary layer with sizable lower/mid-tropospheric dew point spreads. Into the early through middle portion of next week, the mid/upper flow evolution becomes more unclear, but guidance continues to indicate little potential for organized severe thunderstorms.
