Get ready for much hotter temperatures, elevated fire danger, impacted air quality, and the potential for mountain thunderstorms ahead for the rest of this week in your forecast. High pressure to our east continues to build west towards northern California Wednesday. This ridge will be the dominant feature in our forecast for the remainder of the week, and is bringing the return of dangerous heat to our region. The ridge to our east will also pull monsoonal moisture north towards northern California, and this will give us the potential for scattered showers and thunderstorms in our mountain areas in the afternoon and evening hours in out mountain zones today through Saturday. Skies are mostly clear of clouds this morning, but smoke is still blanketing portions of northern California to start the day. Smoke will continue to bring big impacts to our air quality as long as we have active fires, and the rest of this week is no exception. Some thin clouds will move in later today, and the HRRR model is even showing a slight chance for some isolated active weather in our mountain areas. Temperatures have mostly dipped into the 60's to 70's in the valley and foothills overnight, and mountain areas are starting out in the 40's to 50's this morning. Winds are mostly out of the northeast early today, but will shift to become out of the south in the valley. The foothill and Sierra can expect west winds to 10mph today, and Trinity County can expect southeast winds this afternoon. Humidity will dip into the 10 to 20 percent range today. High temperatures are projected to end up in the 105 to 110 degree range in the valley, and in the low 90's to lower triple digits in our foothill and mountain areas this afternoon. An Excessive Heat Warning is in effect in western Siskiyou County through 11pm Saturday. A Heat Advisory will be in effect in Trinity County from 1pm Wednesday through 5pm Thursday. An additional Heat Advisory has been issued for Modoc County and the eastern side of Siskiyou County from 1pm Wednesday through 9pm Friday. The heat will be dangerous over the next several days, and our fire danger will remain high.
High pressure will stay strong to our east over the next several days, and that will keep our temperatures dangerously hot. The ridge will also tap into monsoonal moisture from our south, and draw some of that north into our region over the next several days. This will result in the potential for scattered showers and thunderstorms in our higher elevations during the afternoon and evening hours from Thursday through Saturday. Temperatures in the valley will top out in the 104 to 110 degree range, and only dip into the 70's in the overnight hours through this weekend. Foothill areas will have low temperatures in the 60's to 70's, and high temperatures in the 90's to lower triple digits through this weekend. Mountain areas will have low temperatures in the 50's to 60's, and high temperatures in the lower 90's to triple digits through this weekend. The heat will be dangerous through your extended forecast, so make sure you're staying hydrated and dressing for the hotter temperatures.
Low pressure approaching the West Coast from the Pacific will bring a modest cooling trend and the potential for showers back into our forecast next week. The cooling trend looks likely, but the potential for showers is still very much up in the air. This low pressure on the way will also bring the potential for stronger winds to our forecast early to mid week next week.