October 30, 2018 – Breezy north winds this week with elevated fire weather concerns. Dry with warmer temperatures for the remainder of the week. Red Flag Warning from 11 PM this evening to 11 AM PDT Wednesday.
Discussion
Clear skies across interior NorCal early this morning other than a few high clouds spilling over the building ridge over the eastern Pacific. Locally breezy northerly winds have continued overnight as the surface gradient has tightened (MFR-SAC nearly 9 mbs) with a few spots across the northern Sierra foothills and along the western edge of the Sacramento Valley reporting gusts of 25-35 mph. Temperatures are running much cooler compared to 24 hours ago in the wind-sheltered mountain valleys while breezier locales in the Sacramento Valley are milder. Current readings vary from the lower 20s in the mountain valleys to around 60 at the north end of the Sacramento Valley.
Breezy north winds will continue today with gusts of 25-35 mph possible along the western edge of the Sacramento Valley and adjacent Coast Range foothills.
Similar winds (but northeast) will continue this morning, and return again tonight, near the west facing canyons of the northern Sierra Nevada and foothills. This will bring lowering humidity and combine with the breezy winds to create critical fire weather conditions into early Wednesday. A Red Flag Warning is in effect.
Upper level ridge will build onto the West Coast for the second half of the week with somewhat less breezy winds and warmer temperatures. Halloween afternoon/evening looks dry and mild.
Extended Discussion (Saturday through Tuesday)
We are going to remain under a ridge of high pressure during the extended period as short wave troughs pass to our north and east. High temperatures for the weekend will remain well above average running about 10-15 degrees above normal. Some cloud cover is also expected throughout the weekend. Depending on the placement of the short wave trough on Saturday we may see breezy north winds develop during the afternoon. There is some model disagreement and confidence in low on how strong the winds will get. Isolated showers will be possible in far northwest Shasta County Sunday night as one of the short wave troughs pass just to our northeast otherwise dry conditions are expected for the period.