JACKSON, Wyo. — A prolonged stretch of warm and dry weather over the first 10 days of October came to an end on Sunday when a storm system arrived, bringing much cooler temperatures and up to six inches of snow in the mountains.
The pattern change has likely put an end to 70-degree weather for the year as cooler and more seasonal temperatures are forecasted in the coming days and weeks.
October begins with above-average warmth
Jackson Hole enjoyed a remarkable stretch of 70-degree temperatures over the first week and half of October. The warm and dry conditions allowed for a welcome extension of summer outdoor activities that shut down early last fall during a record cold October.
Through the first 10 days of October this year, the Jackson Hole Airport recorded high temperatures above 70 degrees — a rare long streak of warmth for this late in the year. Average high temperatures in early October are in the low 60s.
Given the clear and dry pattern in place along with decreasing daylight hours, low temperatures plummeted well into the 20s most mornings through the first 10 days of the month as 50-degree day versus night temperature swings were common.
Despite the chilly mornings, overall temperatures so far have been well above average this October in Jackson Hole and throughout the Western U.S.
Weekend storm brings cooler temperatures and several inches of mountain snow
The dry spell came to an end on Saturday night and Sunday (October 10-11) as a storm system arrived, bringing welcome precipitation to our region where fire danger has remained very high.
Total rain and precipitation amounts ranged from 0.7-1.2 inches in the Teton Mountains (highest totals at Jackson Hole Mountain Resort) and 0.4-0.6 inches in the Jackson Hole Valley.
Snow levels fell to the valley floor on Sunday morning as well with a dusting in the town of Jackson and up to an inch north and west of town.
Across the higher elevations, 6 inches of snow fell at Jackson Hole Mountain Resort above 9,000 feet and 5 inches fell at Grand Targhee.
The lingering fall colors and snow-capped mountains made for some beautiful scenes on Sunday.
Cooler but not especially wet pattern to prevail during the next 1-2 weeks
The main “long-term” change to the weather pattern is that much cooler temperatures are here to stay compared to what we experienced during the first 10 days of October — at least in terms of high temperatures.
Occasional light rain/snow events can be expected during the next week, but no major precipitation accumulations are anticipated. This stretch of “slightly unsettled” weather could persist into next week as well.
The next system will bring rain showers on Tuesday, but milder air arriving will result in higher snow levels (generally above 10,000 feet).
Then, a cold front will arrive on Wednesday morning, leading to colder and drier conditions in the days to follow. High temperatures will only be in the upper 40s in the valley on Wednesday and Thursday, before warming up into the 50s on Friday.
Over the weekend, another weak system will slide in from the northwest, resulting in chances for mountain snow and valley rain. However, precipitation amounts are expected to be light and spotty at this time.
Winds have been strong on Monday, and this trend will continue on Tuesday and Wednesday as well before decreasing late in the week. Sadly, the strong winds will likely blow most of the remaining leaves off of the trees in the coming days, closing the door on what has been a fantastic season for fall colors.
Alan Smith, Meteorologist, jacksonholeweatherforecast.com
