The bottom line? A big ridge of high pressure has set up shop across the western U.S. leading to inversion haze, bad air ...

High pressure will keep the Northern Rockies under a stagnant weather pattern through early next week. Expect valley fog, low ...

The bottom line? High pressure ridge continues to build with declining air quality in northern valleys but rebounding ...

KOIN 6 Chief Meteorologist Josh Cozart explains why this week's temperature inversion is reducing Portland's air quality.

High pressure remains in place with valley inversions setting up. Valley fog and cooler air will remain in the lower ...

It was the warmest December in modern history in more than 80% of California counties, even after a chilly start.

High pressure in place will contribute to dry, clear skies in the week ahead, while also creating a temperature inversion.

KOIN 6 Chief Meteorologist Josh Cozart explains why Portland's temperature inversion is causing poor air quality across the ...

This fog is forming because a strong inversion is in place, trapping cold air and moisture near the ground. Valley locations ...

A long stretch of humid heat followed by intense thunderstorms is a weather pattern historically seen mostly in and around ...

Western Idaho remains locked in stagnant weather with expanding valley fog and temperature inversions creating contrasting ...

The bottom line? A big ridge of high pressure sets up shop across the western U.S. leading to inversion haze, bad air quality ...