Chilly pattern out West to give way to early October warmup
A plunge of cool air has overtaken the western part of the nation, but AccuWeather meteorologists say its staying power will be short with warmer, drier weather already on the horizon.
People will be reaching for warmer clothes just in time for October as temperatures will plunge below the historical average and unsettled conditions develop.
A burst of chilly air with rain and high-elevation snow will continue into the first few days of October in the western United States, but AccuWeather meteorologists say its staying power will be fleeting.
A plunge in the jet stream arrived on Saturday and brought a dreary and cool end to the month of September from portions of Northern and Central California to Montana. The autumn chill will expand eastward during the first days of the new month before a big warmup will be in the cards toward the latter part of this week.
Storm dropping temperatures, along with rain and mountain snow
The most widespread and dramatic change to autumn weather yet this season is overtaking the Western states into the first days of October, requiring some residents to break out sweaters or fleece.
High temperatures will be 10-20 degrees Fahrenheit below the historical average into early week, including in places such as Salt Lake City and Las Vegas.
"Around Las Vegas, highs in the 70s are forecast into Monday which is more on par with early November," AccuWeather Senior Meteorologist Alex Sosnowski said.
Record low daytime temperatures were challenged in a few Southern California locales through Sunday, where highs only topped out in the 60s and 70s, as opposed to the 80s and 90s.
"Despite the cool conditions, snow levels will remain high across the West as this storm continues east, and snow will be limited to the highest elevations of the Rockies," AccuWeather Meteorologist Haley Taylor said.
Given the high-level nature of the accumulating snow, generally from around 8,000 feet and up, travel impacts are likely to be limited.
"While snow isn't likely to cause much in the way of travel disruptions yet with this early season storm, it still serves as a reminder that winter is rapidly approaching," said AccuWeather Senior Meteorologist Jake Sojda.
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Rain showers that dampen the road and lead to slippery conditions are expected to be the most widespread impact to travelers throughout the West over the coming days.
"Major problems from flash flooding, mudslides and other debris flows are not anticipated. However, when mixed with oil deposits on the roads, rain will create slick conditions on some highways and intersections," Sosnowski said.
Early October to turn drier, warmer
Showery weather can continue across portions of the Northwest early in the new week as chilly air lingers but much of the region will experience a shift toward drier conditions.
"High pressure will begin to move in behind this storm, however and temperatures can climb some each day across the interior from the middle to the end of the week," Taylor said, adding that it would a more gradual temperature change rather than the quick cooldown experienced this weekend.
The warmest weather, compared to the historical average, is forecast to build along the Pacific coast states with temperatures potentially reaching 15 degrees above what is considered the norm for early October.
"It is not out of the question that downtown Los Angeles experiences a 90-degree day by later [this] week," Taylor said.
The warmer weather, while not quite putting folks in the fall mood, will promote more opportunities to get outside and enjoy the season's beauty as dry conditions are expected to accompany the temperature shift.
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