We'll be staying hot and the chance for mountain thunderstorms will return to Northern California today. High pressure centered to our East is keeping temperatures up to around or above average this afternoon, and low pressure passing through to our South will kick up enough instability to cause more mountain thunderstorms today. The threat of thunderstorms along with gusty winds has prompted National Weather Service offices from Sacramento and Reno to issue a Red Flag Warning for high fire danger in areas of Plumas, Lassen, Modoc, and Siskiyou Counties today. It also extend to the South and East of our area. The Red Flag Warning is set to be in effect from 5AM through 9PM in areas of Lassen and Plumas Counties, and from 11AM through 11PM in areas of Modoc and Siskiyou Counties. Lightning sparked fires will be very possible, and gusty winds could result in rapid fire spread.
Valley and foothilll areas are mostly starting out in the 70's this morning, while mountain areas are in the 50's to 60's. Winds are out of the Northeast to around 10mph, but will shift to become out of the South to 10mph this afternoon. Gusts up to 20mph will be possible in the valley, and 50mph gusts out of the Southwest are not out of the question for portions of the Sierra. Humidity is expected to drop into the 15 to 30 percent range this afternoon, and our air quality will more than likely be impacted by smoke from the current fires burning in our region. The biggest impacts to air quality can be expected in the mountain and the north end of the valley. Temperatures will end up in the high 90's to triple digits in the valley this afternoon, in the high 80's to 90's in the Foothills and Sierra, and in the 90's in the Northern Mountains.
Temperatures will be just as hot, if not a little hotter, on Tuesday, but the threat of thunderstorms will be heading to our East. We'll start to cool back into the mid 90's to low triple digits in the valley on Wednesday, while mountain and foothilll areas end up in the 80's to low 90's. Valley areas can expect low temperatures in the 60's to low 70's, and high temperatures in the mid to high 90's on Thursday and Friday. Foothill areas will dip into the 60's to low 70's, and will top out in the 80's to low 90's late this week. Mountain areas will dip into the 40's to 50's, and end up in the 80's to low 90's late this week.
High temperatures will heat back up as we head into your upcoming weekend, with valley areas topping out in the 90's to trilpe digits, and higher elevations in the low to mid 90's.