A strengthening El Niño, with NOAA assigning over 90% odds of a very strong event through winter 2026-27, stands as the dominant driver shifting early-season snowfall probabilities. This pattern historically favors a southward storm track, elevating moisture and snow potential in the southern Rockies and Sierra Nevada while suppressing it across the northern tier and Great Lakes, where cities like Buffalo or Chicago often see first measurable snow (≥0.1 inch at official stations) by early-to-mid November on average. Late September 2026 conditions remain mild in many regions, with limited high-elevation accumulations reported in the Rockies and Canadian ranges, though lake-effect setups near the Great Lakes warrant monitoring. Key upcoming catalysts include the next NOAA Climate Prediction Center El Niño advisory, updated GFS/ECMWF model runs for October cold-air intrusions, and National Weather Service daily climate reports that will confirm any initial trace or measurable events at resolution stations.