JACKSON, Wyo. — An unseasonably strong early fall storm system and cold front will move across Wyoming from the north this evening, and the latest trends are hinting at the potential for a rare sustained high wind event in Jackson Hole from Monday night into Tuesday morning.
This storm system will result in heavy early season snow along and east of the Continental Divide in Wyoming, while precipitation-wise we will see more of a glancing blow in Jackson on Monday evening with rain showers, mountain snow showers and perhaps a few flakes reaching the valley floor before it ends.
However, a large change in pressure behind the cold front that moves through along with unusually strong northeast winds at the mid to upper levels of the atmosphere will lead to what is known as a downslope wind event — in which winds are accelerated as they move downhill into the valley.
Typically, these downslope wind events occur east of the Continental Divide in areas such as Dubois, Cody and Lander, but this is an unusual setup in which a strong flow aloft from the opposite direction as what is typical (northeasterly instead of westerly) will result in sustained strong winds in Jackson Hole out of the north/northeast traveling downslope from the Absaroka and Gros Ventre Mountains.
The National Weather Service in Riverton has issued a High Wind Warning for Jackson Hole from 9 p.m. Monday through 9 a.m. Tuesday with a forecast of 40-50 mph sustained winds with gusts to 70 mph possible.
Be sure to prepare this evening and secure any outdoor items that could be blown away or damaged by the strong winds. Also, be prepared for the potential for power outages and damage to trees overnight and into Tuesday morning.
Winds will decrease during the day on Tuesday, but will still remain a bit gusty out of the north with much colder temperatures expected.
Alan Smith, Meteorologist
