February 17, 2020 – Dry conditions and above average temperatures continue this week. Breezy northerly winds through mid-week.
Discussion
Winds beginning to transition to northerly as dry cold front slowly moves south through NorCal. Gusts in the teens to mid 20s mph are being reported across the northern half of the Sacramento Valley. Skies are mostly clear across the area except for some patches of high clouds. Current temperatures range from the 20s in the mountain valleys to the mid 40s to mid 50s across the Central Valley.
North to east gradients will continue to tighten this morning (MFR-SAC is already nearly 9 mbs and the RNO-SAC is approaching 2 mbs). Winds will pick up this morning in the Central Valley as mixing develops, and will be quite breezy to windy along the western edge of the valley where a northerly barrier jet sets up. The north gradient is forecast to peak today while the east gradient will increase into tonight.
Local gusts of around 40-50 mph will be possible in the favored windier spots near the mouth of the Feather River Canyon and over the ridges of southern Lake County. Gradients slacken by Tuesday afternoon, but some breeziness will be possible again on Wednesday.
Dry weather with mild (above average) daytime temperatures forecast to continue through Thursday as next upstream trough splitting off the coast late in the week with most of the energy forecast to go south of us. Some increase in clouds will be possible Thursday.
Extended Discussion (Friday through Monday)
A closed off upper level low will be dropping into SoCal for the start of the extended period. Moisture will be low and the majority of the forcing will be to our south keeping precip chances very low. Short wave ridging builds in on Saturday before pushing east Sunday as a trough drops from the NW. This will bring shower chances to NorCal starting Saturday night and continuing into Sunday. The best shower chances look to be during the morning hours as a cold front pushes through the region. Deterministic models and even ensemble mean are trending this system a bit further east giving it more of an inside slider look and similar path to our last few systems. If this trend continues PoPs will be less likely. Mountain showers linger into Monday and north winds develop as the trough pushes east. Above average temperatures are expected for the start of the period with them returning to near normal by Sunday.