BILLINGS — Through Thursday, most of the region will continue to experience unseasonably warm conditions, with temperatures climbing into the 70s and 80s, 10 to 20 degrees above what's typical for late September and early October. It's like an extended summer finale before autumn finally takes center stage.
However, not everyone will feel this warmth equally. Areas west of Billings will enjoy more moderate conditions in the 70s, courtesy of a cooling upper-level trough moving in from the west.
Tuesday brings the first chance for precipitation for the lower elevations, mainly in areas west of Miles City. Don't expect anything dramatic with just a 20-40% chance of showers and weak thunderstorms.
The rainfall will be modest with expectations low for significant accumulation. Less than a 20% chance exists for areas to receive more than a tenth of an inch.
Thursday night through Friday marks the beginning of a completely different weather story. High confidence exists that temperatures will tumble to near or below normal values.
The region's mountain ranges are primed for their first widespread snowfall of the season. From Thursday through early next week, multiple precipitation opportunities will develop, though the exact timing and amounts remain uncertain.
Initially, snow levels will stay relatively high—between 8,000 and 9,000 feet Thursday through Saturday. But by Sunday, a more significant cooling trend could drop snow levels into the 6,000 to 7,000-foot range, potentially bringing to foothill locations like Red Lodge.
Friday and Saturday will see a return to more seasonal conditions with highs in the 60s, followed by a further cool down Sunday and Monday that will keep temperatures in the 50s.
This forecast represents a classic late-September weather pattern—the last gasp of summer heat giving way to autumn's cooler, more unsettled conditions, complete with the season's first mountain snow.
