Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 226 AM EDT Thu Oct 2 2025 Valid 12Z Thu Oct 02 2025 - 12Z Sun Oct 05 2025 ...Northern Rockies... Day 3... An upper low over the Great Basin on Friday opens into a trough and shifts east over the Rockies late Saturday. Lee-side cyclogenesis over western South Dakota occurs during this time enhancing flow from Gulf-sourced moisture over the Plains through the northern Rockies. Snow levels through Saturday are around 9000ft over the Absarokas, Wind Rivers, and Bighorns, above which probs for >6" snow from 12Z Saturday to 12Z Sunday are 40-80%. The probability of significant icing is less than 10 percent. Jackson