February 13, 2020 – Dry this week except a chance of showers over mainly the mountains this weekend. Above average temperatures continue.
Discussion
Mid/upper level ridge is moving across NorCal early this morning with clear skies, other than a few high clouds, overhead. Winds are generally light as the lingering north gradient has subsided. Current temperatures range from the upper teens to mid 20s in the mountain valleys, to the 40s across the Central Valley.
Ridge will continue to move east today as upstream trough off the PacNW moves onshore to our north. The system will have little effect other than to cool temperatures across the region a few more degrees.
Ridging will continue dry and mild weather into the weekend. Another trough will move in on Sunday and will bring a chance of light precipitation to mainly the mountains.
Extended Discussion (Monday through Thursday)
An upper trough will be positioned east of the region on Monday with deep-layered northerly flow in its wake. Dry, gusty northerly winds are likely the first couple of days next week. Into the Sierra, winds will have more an easterly, downslope component. This ultimately maintains an extended period of low daytime relative humidities. The guidance continues to advertise a closed low possibly pinching off over the southwestern U.S. Ensemble predictability is low accompanied by poor run-to-run model continuity. Will maintain dry conditions next week with breezy winds possibly extending into Wednesday depending on how the mentioned upper low evolves. Toward the end of next week, split flow over the Pacific becomes evident while the weather remains dry over northern California. High temperatures should generally run around 2 to 5 degrees above climatology.