Dry and warm into the weekend with record highs possible. Stronger north to east winds possible Tuesday through Wednesday, potentially bringing elevated localized fire weather concerns after extended period of dry conditions and warm temperatures. Increasing mountain showers chances Monday night with light snow at pass level.
Discussion
Unseasonably strong Pacific high pressure will remain over NorCal through the weekend. Ridge will begin to flatten late Sunday, as upper low takes shape over the Pacific Northwest. The main impact for our weather into the weekend will be record high temps in many locations. Especially, over the northern and central Sacramento Valley where readings will top out in the mid to upper 80’s this afternoon. The current February all-time max high for Redding is 87 in 1920 and 85 in 1977 for Red Bluff and highs today will be again approach those marks. High temperatures over the Delta, southern Sacramento and northern San Joaquin Valleys will be from the low to upper 70’s today into the weekend, which will be in range for more daily high temps at many locations.
Overnight lows will also be mild, especially in the thermal belts where readings will be 5-15 degrees above normal. Clear skies, a dry airmass and light winds will allow good radiational cooling for wind-sheltered valleys where lows will be closer to average.
Ensembles indicate that an upper low will drop south into the Pacific Northwest Monday and down the southern Cascades Monday night. A more westward track has been trending over the past several model runs for the low and confidence seem to be growing given the westward shift of all cluster members on the latest 00z run.
Breezy onshore southwest flow will develop ahead of this system, especially over the ridges, where gusts up to 35 mph will be possible Monday afternoon.
The trend has been also been wetter with this system. WPC and NBM guidance are both showing wetting rains with amounts from 0.10 to 0.30 inches over the mountains Monday night. Even light snow amounts of 1 to 3 inches above 5,000 feet. Only very light rain amounts expected over the Valley with less than 0.10 inches.
Extended Discussion (Tuesday through Friday)
Upper low digs through CA on Tuesday with models continuing to generate scattered showers over portions of interior NorCal. Best chances for precipitation on Tuesday appear to be along the west slopes of the Sierra Nevada. GFS showing higher QPF totals than EC. WPC guidance attm showing less than a tenth in the Central Valley, with around a tenth upwards to near half an inch along the eastern foothills and mountains. Snow levels Tuesday morning lower into the upper foothills. Snow totals locally up to 4 inches possible over higher elevations of the Sierra Nevada.
Periods of breezy to windy conditions expected Tuesday into Thursday as strong high pressure offshore attempts to fill the low. Potential for elevated fire weather concerns.
Locally gusty wind lingers in the eastern foothills/mountains early Friday, otherwise lighter wind expected. General warming trend forecast through the extended forecast period.