When it comes to fall, residents who live in the Rockies know to be prepared for anything. Thunderstorms, wild temperature swings, and snow are just a few of the things you can expect this time of year. And sometimes they all come at the same time… like this week.
When fall officially starts Thursday morning, areas from the Grand Canyon to Yellowstone National Park will be dealing with the threat for heavy rain. Flash flooding will be possible, especially across burn scar areas in southeastern Idaho and western Wyoming. Thunderstorms are likely Thursday afternoon and some could be severe with damaging winds and moderate to large hail.
Much of the heavy moisture expected across the west is associated with a former Tropical Depression (Paine) that moved through Baja California earlier this week. This system is no longer a named storm, but the leftover moisture will interact with a strong incoming cold front to create heavy downpours.
As the cold air behind the front meets up with the moisture, the rain will switch over to snow for several areas above 7,000 feet. Half a foot or more of mountain snow accumulation is possible in portions of Utah and Idaho. Snow will not make it all the way down to the Salt Lake Valley, but temperatures will be more than 25 degrees below normal Friday afternoon in Salt Lake City with highs struggling to make it above 50 degrees.
For WeatherNation, Meteorologist Corey Christiansen