An air stagnation advisory for the Tri-Cities has been extended a week.
A ridge of high pressure is expected to remain almost stationary over the Tri-Cities, with pollutants trapped near the ground.
The advisory now is set to expire at 10 a.m. Friday, according to the National Weather Service.
Patches of sometimes dense and freezing fog also are forecast, with freezing fog possible from 10 p.m. to 10 a.m. each night through Friday. Highs should be in the upper 30s each day and lows in the 20s, warming to the upper 20s through the work week.