Get ready for dangerous heat on the way in your forecast. High pressure centered in the Desert Southwest will absolutely dominate our forecast today and our extended forecast. Well above average temperatures are expected for your entire 7 day forecast. The Excessive Heat Watch has now been upgraded to an Excessive Heat Warning for the valley and foothills from noon on Friday through 9PM on Wednesday. We'll also have an Excessive Heat Warning in effect for Western Siskiyou County from 11AM Friday through 11PM Sunday. A Heat Advisory will be in effect in Trinity County and the remainder of Siskiyou County. Trinity County will be under a Heat Advisory from noon Friday through 7PM Saturday, but that could very well be extended or upgraded.
Skies are mostly sunny to partly cloudy for the start of your Friday and will stay that way through the day. Low pressure off the coast of Southern to Central California is providing the clouds and will bring a slight chance for Sierra thunderstorms this afternoon, but that active weather is expected to stay to our south over the next few days. Temperatures are starting out in the 60's to 70's in the valley and foothills this morning, and mountain areas are ranging from the high 40's to low 60's. Winds are out of the Northeast this morning and will mostly be out of the north to 10mph today. Some north valley areas may see modest south winds for a brief period this afternoon and evening. High temperatures are projected to top out in the 103 to 109 degree range in the valley, while foothill and Sierra locations end up in the 90's. The Northern Mountains will top out in the 90's to triple digits this afternoon.
The heat will persist through your extended forecast, and we'll continue to see clouds and a slight chance for Sierra thunderstorms through Tuesday. The best chance for thunderstorms in our portion of the Sierra looks to be Monday afternoon and evening. Overnight low temperatures will only dip into the 70's to 80's in the valley and foothills, while mountain areas end up in the 50's to 60's overnight. High temperatures in the valley are currently projected to be in the103 to 112 degree range through the middle of next week, while foothill and Sierra locations end up in the mid to high 90's, and the Northern Mountains top out in the 90's to triple digits. Low pressure moving into our north will bring a very modest drop in temperatures for the end of next week, but valley areas are still expected to end up in the triple digits.
With a heat event like this ahead it's important to remember to do everything you can to be prepared. Heat is the number 1 weather related killer in the US, and heat illness will be very possible through your entire extended forecast. Stay hydrated and avoid drinking alcoholic or caffeinated beverages, use air conditioning, wear light colored and loose fitting clothing, check on neighbors and relatives, make sure your pets and livestock have water, and never leave children or pets inside of cars unattended.