February 9, 2018 – Dry and unseasonably warm today with a little cooling over the weekend. Gusty north winds on Saturday. A chance of light showers over the mountains Monday with moderately low snow levels. Another round of Gusty north winds early next week.
Discussion
One more day of very warm conditions expected today as high pressure aloft remains over the eastern Pacific and west coast. As with the last several days, a high temperature record or two may fall. Not seeing much valley fog this morning and expect any fog later will be very minimal. Models are consistent in dropping a shortwave trough into the Pacific Northwest tonight and then into the Great Basin on Saturday.
Northerly flow develops behind this system bringing cooler air into the region for a significant drop in daytime temperatures. Although highs will remain well above normal, daily high temperature records should no longer be in jeopardy.
Bigger weather issue Saturday will be breezy to gusty northerly winds. GFS predicts a surface gradient of more than 10mb with good upper level support. The strongest winds will be over the Sacramento valley and foothills especially along the west side and are modeled to be just strong enough to warrant a minimum wind advisory. Model wind speeds may be just a bit weak considering predicted gradient so these wind speed predictions may go up a bit. Wind speeds drop off Saturday night and Sunday as gradients relax.
A bit more cooling may occur on Sunday but changes will be small. Another weather system drops into the Pacific Northwest late Sunday bringing a slight chance of showers to the northern mountains Sunday night and then over the northern Sierra on Monday as this system moves into the Great Basin. Elsewhere will see some cloud cover and a little more cooling. Another round of breezy north winds will kick in starting late Monday.
Extended discussion (Tuesday through Friday)
High pressure will continue to bring dry and warm conditions through the end of next week across northern California. Afternoon high temperatures will range between 5 and 10 degrees above normal for mid February. A stray mountain shower cannot be ruled out, although any chance of precipitation in the long term forecast period is unlikely.