Advisory Archive

After the snowstorms that ended 10 days ago I was wondering if we’d revert to an Indian summer or continue in a wintery pattern. Snowfall the last two nights points to winter, at least for now.

In the last 48 hours SNOTEL and ski area weather stations are showing 3-4” in the northern mountains, 6-7” around Big Sky, 3-6” outside West Yellowstone and 1-2” near Cooke City. Mountain temperatures are in the mid to high 20s and ridgetop winds are blowing N-NW at 10-20 mph. Tonight we’ll get another 4-6” with winds blowing 15-25 mph out of the N-NW.

It is the last day of summer and mountain SNOTEL stations show up to 10 inches of snow on the ground. The mountains received 3-4” water equivalent precipitation over the past week, which totaled 2-3 feet of dense snow at high elevations. Temperatures have been high 20s to 30s F, with winds south to westerly at 10-20 mph with gusts to 40-50 mph.

Fall will begin with well below average temperatures in the 20s F, and snow above 4000 feet. Valley rain this afternoon will become snow at all elevations early Friday morning. By Friday evening the mountains could have 10-15” of new snow with 2 feet in the highest ranges. Warmer, drier weather returns Sunday through next week.

This weekend welcomed a change to cold, wet weather. Brackett Creek SNOTEL in the Bridger Range recorded 3” of precipitation over 48 hours, which totaled 2.5 feet of snow at high elevations (Outside our advisory area, the Tobacco Roots had similar snowfall). The mountains near Big Sky, West Yellowstone, Cooke City, and the Hyalite area got around a foot of dense snow.

The immediate forecast holds a good outlook for more snow, but October weather will determine if these are the first layers of our winter snowpack. As a cold front passes this afternoon wind speeds could gust 40-60 mph, and the mountains above 5500 feet are expected to get 3-5” of snow Tuesday morning. Valley rain and mountain snow are forecast periodically through Saturday morning. Sunday may host dry weather, with a possible return to cool and wet weather next week.

At 6 a.m. the mountains have 4-6” of new snow. Temperatures are high teens to 20s F and wind is west-northwest at 5-20 mph. Today, temperatures will be 20s to low 30s F with west to northwest wind at 15-25 mph. The mountains will get 1-2” of snow this morning before dry weather prevails tonight through tomorrow. More mild and unsettled weather is in the forecast later this week.

At 4 a.m. the mountains have 3-4” of new snow, which began as rain up to 8,000 feet yesterday evening. Temperatures reached the mid-40s F yesterday, and southwest wind was 30-50 mph with gusts of 60-85 mph. Temperatures this morning are mid-20s F to just below freezing with southerly wind at 5-15 mph. Today, temperatures will reach mid-30s F with south wind at 5-15 mph, and tonight wind will shift to the west-northwest at 20-30 mph. Expect light rain and snow in the mountains today with a chance for thunderstorms this afternoon and heavier snow showers tonight. The mountains will get 3-5” of snow by morning with more tomorrow.

At 5 a.m. there’s no new snow to report, only warm temperatures and wind. Freezing level is near 10,000’ and mountain temperatures are in the high 30’s F to mid-40s. Winds are from the southwest at 20-30 mph with gusts of 50 mph. This afternoon skies will be cloudy and thunderstorms may occur with an approaching cold front. Tonight, freezing level drops to 7,000’ and winds will remain strong from the southwest. Rain will turn to snow and by morning I expect 2-4” in the southern mountains.

This morning temperatures are in the upper 20s to low 30s F and winds are blowing 10-20 mph out of the W-SW with ridgetop gusts around Big Sky breaking 30 mph. Today, temps will be 5-10 degrees warmer than yesterday with highs reaching the upper 30s to low 40s F. Winds will increase out of the W-SW with ridgetop gusts pushing 40 mph by this afternoon. Skies will remain partly to mostly cloudy and there’s an increasing chance of precipitation this afternoon. Some areas may even see isolated thunderstorms as a weak system moves through the area. Tomorrow looks to be another unsettled day with the potential for valley rain and mountain snow.

Over the past 24 hours no new snow has fallen over the advisory area. At 5 a.m. temperatures are in the 20s under clear skies and winds are blowing 10-20 mph out of the W-NW. Today, a ridge of high pressure will produce partly cloudy skies and warmer temps. Highs today will climb into the upper 30s to low 40s F and winds will remain light to moderate out of the W-SW. No new snow is expected over the next 24 hours.

In the last 24 hours, 3” of snow fell up Hyalite and 1” fell everywhere else. Temperatures are in the teens and winds are 10-20 mph out of the N-NW. Skies will clear this morning and today will be sunny with temperatures reaching the upper 20s with light northwest winds. Tonight will be clear and tomorrow will be sunny and much warmer.

Grab an extra layer for temperatures in the single digits to teens F this morning and highs in the 20s F today. Overnight, the mountains got 1-2” of new snow with 3-5” near West Yellowstone. Wind this morning is northwest at 10-20 mph with gusts to 30 mph. Today will be mostly cloudy with snow showers increasing this afternoon, and northwest wind at 5-15 mph today will shift northerly at 10-20 mph tonight. Tonight, the northern mountains and Cooke City will get 3-5” of low density snow with 1-2” near West Yellowstone.