Thursday, September 7, 2017
A trough of low pressure approaching the Pacific Northwest will split today, with the southern piece forming a meandering closed low off the California coast and the northern piece moving eastward across the U.S. - Canadian border. The northern portion will move the ridge of high pressure currently over the western states east of the Steamboat Springs area by Friday afternoon, with weak southerly winds behind the ridge and ahead of the closed low off the West Coast directing moisture toward Colorado and smoke from the local wildfires to our northwest away from the city.
However, the southerly flow is not strong, so it is unclear how much smoke will be scoured from the area, though an improvement in air quality is very likely. Additionally, the weak flow will limit the amount of moisture that moves over our area, so the afternoon storms that may occur Friday, Saturday and possibly Sunday afternoons may produce more wind than rain.
By early in the work week, the western ridge partially reforms behind the eastward-moving wave forecast to be to our northeast, and this reintroduces drier air and weak northwesterly flow for northern Colorado. Therefore, if the local wildfires to our northwest are still producing smoke, we may once again have some smokey and hazy days next week.
Another Pacific wave approaches the West Coast midweek, and dislodges the California closed low. Models disagree on how strong the Pacific wave will be, but agree that the remnants of the closed low will move across the Great Basin and approach our area sometime around the end of the work week.
At this point, I would expect the possibility of some light showers ahead of the closed low near the end of the work week, with a much better chance of wetting rains around next weekend if the closed low moves over our area.