Extremely Critical fire danger in California.
From the Sacramento Weather Office discussion:
A powerful and dangerous offshore wind event will materialize
across northern and central California over the next 12 to 24
hours. This event is forecast to be the strongest event of the
year so far for the region. Consequently, the potential fire
weather impacts will be extreme. The Storm Prediction Center has a
large portion of the region under an "extremely critical" risk,
the highest possible categorical assignment for fire weather.
Fuels are dry and will only further dry, winds and gusts will be
very strong, and relative humidity values will be desert-dry. The
meteorological synoptic setup is uncomfortably similar to recent
past events in northern California such as October 27-28, 2019
(Kincade Fire rapid growth), November 8, 2018 (Camp Fire rapid
growth), and October 8-9, 2017 (2017 Wine Country Fires rapid
growth).
While winds are forecast to gradually subside through the day on
Monday, relative humidity values will drop to remarkably low
values -- less than 5 percent for some locations -- with dew
points at or below 0 deg F (-18 deg C).
To recap...all necessary ingredients will be in place to produce
extremely critical fire weather conditions: 1) strong winds, 2)
low relative humidity values, and 3) dry wildland fuels. Any new
ignitions will be present in an environment that will promote
rapid, explosive, and dangerous spread of fire. Have a plan in
place if you need to evacuate will little/no notice. While Fire
Season 2020 has already been historic from the countless lightning-
based ignitions in August, remember that peak offshore wind
season is right now for much of the Golden State. Be safe and
vigilant during this extremely high-impact and particularly
dangerous fire weather event.