The heat is expected to ramp up across northern California today and the threat of thunderstorms will linger in some higher elevations. The Red Flag Warning for high fire danger was allowed to expire last night, but valley and foothill areas are still under an Excessive Heat Warning through 9PM Wednesday night. There is also a Fire Weather Watch expected to go into effect from Wednesday afternoon through Wednesday evening in areas of Modoc and Lassen Counties.

Skies are partly to mostly cloudy, and temperatures are warm for the start of your Tuesday. Valley areas are starting out in the mid 70's, while foothill areas are in the 70's to 80's, and mountain areas are in the 50's to 60's. Winds are out of the northeast to around 10mph, but will become out of variable directions for your afternoon. Northern zones can expect south winds, while mid valley, foothill, and Sierra areas can expect winds out of the west or southwest. Humidity is expected to dip to below 30 percent in all areas this afternoon. High temperatures are projected to end up in the 102 to 108 degree range in the valley, in the mid 90's to low triple digits in the foothills, in the high 80's to mid 90's in the Sierra, and in the 90's to low triple digits in the Northern Mountains. The best chance for active weather will be in the Sierra today, but there will also be a chance for some activity popping up in the Northern Mountains. Fire danger will mostly be in the moderate to high range this afternoon.

Low pressure moving into our north will help to weakend the influence the ridge of high pressure to our east has had over our region for the last several days, and will result in a modest dip in temperatures on the way for your Wednesday and Thursday. Valley areas will end up in the upper 90's to lower triple digits on Wednesday, and in the mid to upper 90's on Thursday. Foothill and Sierra locations are expected to slide back into the low 90's on Wednesday and upper 80's to low 90's on Thursday, while the Northern Mountains mostly end up in the 80's to 90's over the next few days. There will be a slight threat of thunderstorms and gusty winds along the eastern slopes of the Sierra on Wednesday and that is prompting the Fire Weather Watch for Modoc and Lassen County areas.

High pressure will bring temperatures back up to around 5 to 10 degrees above average for the end of this week and weekend. There will be potential for another round of active weather tracking up into our region from the south in your weekend forecast, but confidence is currently low on when and where more thunderstorms will be possible. Triple digit heat is likely for the valley for both days this weekend, while foothill and mountain areas mostly end up in the 90's. Some parts of the Northern Mountains may see a return to triple digits as temperatures rise this weekend. The heat is expected to persist through at least the start of next week.