Get ready for dangerous heat on the way for your Labor Day Weekend. Temperatures will be a couple of degrees hotter in most of northern California today, but will become much hotter as we head through the next several days. High pressure will build across our region this weekend and will result in dry and much hotter conditions. An Excessive Heat Warning is set to go into effect for the entire valley, the foothills, the western slopes of the Sierra, and Trinity County from 11AM Saturday through 6PM Tuesday. We'll also have a Heat Advisory in effect from 11AM Friday through 8PM Sunday on the eastern slopes of the Sierra. A Red Flag Warning for high fire danger will also go into effect from 2PM through 8PM Friday for low humidity and gusty winds out of the southwest in Modoc County.
Bigger impacts to air quality and slightly hotter temperatures are expected across northern California today. Air quality is most impacted in areas of Plumas County, where we're starting out in the very unhealthy range this morning. The remainder of Plumas County and most of Lassen County are in the unhealthy range. The foothills, and areas of Trinity and Siskiyou Counties are reporting air quality in the unhealthy for sensitive groups range this mornig, and most valley areas are in the moderate range this morning. Air quality will continue to worsen over the next few days as our airmass stays mostly stagnant. Skies are clear of clouds this morning and temperatures are slightly warmer than 24 hours ago. Valley and foothill areas are starting out in the 60's to 70's, while mountian areas are in the 50's to 60's for the start of your Friday. Winds will mostly be out of the southeast to 10mph today and humidity will dip into the 19 to 40 percent range this afternoon for most of our region. High temperatures will top out in the mid 90's to lower triple digits in the valley and Northern Mountains. We'll mostly end up in the high 80's to mid 90's in the foothills and the Sierra. Fire danger will be in the moderate to high range today.
The heat will be ramping up this weekend as high pressure dominates our region. High temperatures will top out in the 100 to 107 degree range in the valley on Saturday and then in the 105 to 113 degree range on Sunday and Monday. Foothill and mountain areas will top out in the 90's to triple digits from Saturday through Monday. There will be a modest drop in temperatures on the way for your Tuesday, but the Excessive Heat Warning is set to stay in place through 6PM Tuesday evening. An "Inside Slider" is expected to drop down into areas to our east on Tuesday into Wednesday of next week and that will bring the potential for gusty north winds back into our forecast. If the forecast stays on track we could be looking at fire danger becoming a big concern from Tuesday through Thursday with the stronger north winds. Temperatures will mostly dip back into the high 90's to lower triple digits in the valley on Tuesday and will then drop into the mid to high 90's by Thursday of next week. Mountain and foothill areas will mostly be in the 80's to mid 90's for the middle of next week.