JACKSON, Wyo. — We have undergone “weather whiplash” through the first two weeks of September. A warm start to the month with record heat was followed by an unseasonably powerful early blast of cold,snow and wind, but now we are back into a warm and dry pattern.
Check out the observed high and low temperatures in the town of Jackson from September 1 through September 13 to get an idea of the wild temperature swings we’ve been experiencing. The historical average high and low temperatures are noted by the dotted lines.
Recovering from the Labor Day Storm
The storm system that moved through on the night of Labor Day resulted in downed trees and branches across Teton County. The worst of the damage appeared to occur in southern portions of the town of Jackson, such as around Albertson’s Grocery Store.
However, looking at the larger scope, most of the tree damage in Teton County was rather isolated compared to farther south in the Wind River Range, where a historic wind event resulted in extensive tree damage.
According to Bridger-Teton National Forest, “hundreds of trees” had fallen across some of the more popular hiking trails along the western side of the Winds. Hiking season appears to be on hold across much of the range as clean-up efforts begin.
Warm and Dry Conditions Return – Pattern Continues through Thursday
A ridge of high pressure has settled into place across the Rockies, resulting in dry conditions, warm daytime temperatures and chilly mornings.
This pattern will continue through Thursday with roughly 50-degree temperature swings continuing in the valley from day to night with highs in the low 80s and lows near freezing. We are not out of the woods yet in terms of fire danger either, with breezy winds expected most afternoons this week along with very low relative humidity.
Smoke Has Arrived from Wildfires in Oregon
Easterly winds aloft kept the wildfire smoke bottled up near the West Coast for most of last week, but now that winds have shifted to a more typical westerly direction, that smoke has moved inland and is now impacting Jackson Hole.
We will continue to see off-and-on periods of smoke this week due to subtle shifts in winds aloft. Heavy smoke and poor visibility early on Monday should give way to improving conditions on Tuesday and Wednesday as the heaviest smoke shifts north of Jackson.
However, winds will shift again ahead of an approaching trough of low pressure late in the week, so we could see smoke increase again on Thursday and Friday.
The good news is that meaningful rain will finally reach Oregon and the Pacific Northwest on Thursday and Friday, and more rain is possible again next week, which should help to chip away at the devastating fire situation there. California (except for far northern portions) will remain dry, though, as should be expected at this time of year.
Cooler and Showery Weather Arrives this Weekend
A trough of low pressure approaching from the west will result in a round of showers here toward the end of the week along with cooler temperatures this weekend.
Isolated showers and thunderstorms will initially become possible on Friday afternoon, before a better chance of more widespread showers arrive on Friday night and Saturday as a cold front moves through.
For now, this appears to be more of a “showery” type event and not a significant storm system. Rain/precipitation amounts in the ballpark of 0.2-0.4 inches should be anticipated in the mountains with somewhere between 0.1-0.25 inches in the valley. That could change, of course, given this event is still five-plus days out.
Regardless, you’ll want to bring a rain jacket and extra layers if you plan to recreate on Saturday.
As for temperatures, highs should cool off into the 60s across the valley this weekend. As the cold front moves through, snow showers are likely to develop above 10,000 feet on Saturday with snow levels possibly dipping lower, but only light accumulations are expected at this time.
By Sunday, we should dry out with skies becoming mostly sunny.
Alan Smith, Meteorologist, jacksonholeweatherforecast.com
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