Slow improvement continues for the Western Slope

500 millibar winds are transporting heavier smoke in the northwestern United States mostly to the north of Colorado. Image courtesy of the NOAA Storm Prediction Center

The upper level winds over the western United States continue to shift as an upper level high pressure system builds over the desert southwest. The result is less smoke moving into western Colorado from fires to the west and northwest. All air quality advisories west of the Continental Divide will be allowed to expire at 9am Saturday morning.

This does not mean that the air is squeaky clean. Light to moderate levels of smoke remain which could still cause some discomfort, including irritated eyes, nose, and throat. For those that suffer from heart or lung ailments, it is still probably a good idea to take it easy this weekend. The building heat across western Colorado will also be a concern with afternoon temperatures topping 100 degrees in many areas, including Grand Junction.

There will be some areas in western Colorado that will see some locally heavier smoke. This is true in areas near the Elk fire and the Gold Mountain fire. The worst of the smoke will be during the early morning hours along Highway 550 from Ridgway north to Montrose, Highway 149 north of Lake City, and Highway 50 near Blue Mesa Reservoir in Gunnison County.

Eastern Colorado is also seeing levels of mostly light smoke which is currently in the "Moderate" category. One area that could see an increase in smoke over the next 24 hours is northeastern Colorado. This includes the northern Front Range region of Denver, Boulder, and Ft. Collins. It also includes the adjacent plains to the east, where smoke levels could increase for areas to the east of Interstate 25 and to the north of Interstate 70. This area includes Greeley, Fort Morgan, Julesburg, Burlington, and Limon.

There is still some uncertainty to the timing and amount of smoke that might impact this large area, so no additional advisories are being issued at this time. We will be monitoring the situation throughout the weekend and will post here if a new advisory is issued. Please keep in mind that the northern Front Range region remains under an Action Day for Multiple Pollutants until at least 4pm Saturday as the combination of smoke and high ozone continues to cause health concerns along the I-25 urban corridor.