Key Points
- A Red Flag Warning is in effect for much of the central and northern Sacramento Valley and northern foothills thru 11 PM tonight.
- Cooling trend into the weekend with gradual warming trend by the middle of next week.

Discussion
The recent trend of widespread triple digit temperatures in the Valley and foothills begins to end today; currently, temperatures across the Valley and foothills are in the mid 80s to low 90s, with high temperatures in the Valley and foothills expected to range today from the low 90s to just over 100. Temperatures are expected to cool even more dramatically tomorrow, over 10 degrees in some locations, due to an upper low passing over the area. While the low has caused some of the recent gusty winds, the system itself is fairly dry and is not expected to bring any precipitation to the area. Winds themselves will continue to trend down as well, with conditions becoming lightly breezy over the weekend, as opposed to the gusty winds we've been experiencing.

Fire weather conditions in general are expected to improve over the weekend, though a Red Flag Warning remains in effect until 11 PM tonight. Daytime and overnight relative humidities this weekend will be higher in the Valley, temperatures (as previously mentioned) will be cooler, and winds will trend down. However, higher elevations will see less relief in the form of elevated humidities, and fuels are still quite dry, so it will remain important to practice fire safety during this time. Finally, as quickly as the "cooler" weather arrived, it will be replaced by a gradual warming trend early next week. It is however, important to note that there is some ensemble and cluster disagreement over when exactly the low will move on, and how strong it will have remained by that point, meaning that temperatures will be slow on the road back to above normal for the time of year. Monday, high temperatures are expected to remain primarily in the 80s and 90s, only slightly warmer than over the weekend. //SP

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
As we move into the remainder of next week, temperatures will continue their Sisyphean climb back up to normal and above normal conditions. By Thursday, clusters and ensembles seem to be in good agreement that ridging will begin to encroach on the area once again, bringing back the near to above normal temperatures in earnest. Temperatures look to remain around the mid 90s to low 100s in the Valley through the end of next week, though there is some uncertainty as we head into the weekend. Otherwise, warm dry weather is expected through next week, with temperatures gradually increasing and daytime relative humidity gradually decreasing. //SP

AVIATION
VFR conditions over interior NorCal next 24 hrs except local MVFR/IFR possible in haze/smoke vicinity of wildfires. In Central Valley, areas of southerly surface wind 10-15 kts, with gusts up to 25 kts until around 10z. In the vicinity of the Delta, southwesterly surface wind 15-25 kts with local gusts to 35 kts.

STO WATCHES/WARNINGS/ADVISORIES
Red Flag Warning until 11 PM PDT this evening for Burney Basin and Northeast Plateau in Shasta County Including Northwest Lassen NF north of Lassen NP-Central Sacramento Valley in Glenn, Colusa, Yuba, Northern Sutter, and Butte County Below 1000 Ft- Northern Sacramento Valley to Southern Tehama County Line Below 1000 Ft-Northern Sierra Foothills from 1000 to 3000 Ft. Includes portions of Shasta-Trinity and Butte Units-Northern Sierra Including Lassen NP and Plumas and Lassen NF/S West of the Sierra Crest (West of Evans Peak-Grizzly Peak-Beckworth Peak).