December 4, 2020 – Persistent dry weather will continue, above average high temperatures and cool nights. Gusty winds are possible Sunday and Monday which could lead to elevated fire weather concerns for some areas.
Riding will develop today over Northern California and persist into Saturday. Little change will occur today in the daily high temperatures. Another stronger low will pass through the region late Saturday and Saturday night. Models starting to indicate it may be a little stronger than 24 hours ago but still a very weak system. It will bring some cooler air to the region for Saturday though. Currently have some chances of precipitation along the coastal range and over the north end of the valley for Saturday evening then over mainly the upper elevations of the Sierra Nevada north of US-50 late at night. Amounts look to be less than a quarter inch in rainfall and less than an inch in snowfall for the higher elevations above 5000 to 6000 feet.
Behind the system north winds will develop on Sunday becoming stronger Sunday night and peaking Monday in the valley. Potential for a wind advisory late Sunday night and Monday for the valley will increase fire danger for parts of the valley, mainly the westside. Mountain and foothill winds will increase as well Sunday night through Monday morning. Warmer temperatures are expected for Monday with the downslope winds helping to bring back well above normal temperatures.
Extended discussion (Tuesday through Friday)
By Tuesday morning, an upper closed low will be located just west of the Baja Peninsula with broad ridging across Northern California. A shortwave passes over the Pacific Northwest Tuesday night into Wednesday, with another possible wave skimming across far northern California Thursday night into Friday. Any precipitation chances look to stay north of the area at this time, with the main impact being some possible offshore winds late week. Unseasonably mild high temperatures remain through Thursday, with highs anywhere from 5 to 15 degrees above normal for this time of year.