Dry and mild through the weekend with record highs possible. Pattern change early next week brings cooler temperatures along with a chance of mainly foothill and mountain showers. Breezy northerly winds behind the system may bring locally elevated fire weather concerns Tuesday and Wednesday.
Discussion
Strong high pressure is centered to the northwest of the area off the PacNW coast. Other than a few high clouds over the southern half of the forecast area, skies remain clear over NorCal. Northerly surface pressure gradient has slackened considerably compared to 24 hours ago and winds are generally light across the Central Valley. East gradient remains nearly as tight as 24 hours ago, and local east winds in the teens to around 30 mph continue in the foothill and northern Sierra.
Warm and dry conditions will persist today and Sunday as the strong ridge begins to shift east. Highs today and Sunday will be similar to Friday’s across most of the region, however the northern Sacramento Valley is expected to be not quite as warm as north winds slacken. Daily record highs will once again be in jeopardy as highs top out in the mid 70s to lower 80s across the Central Valley.
Big change to cooler and more unsettled weather develops early next week as a strong short-wave trough drops down from the north. Models have remained pretty consistent with the timing and strength as the strong vort is forecast to swing through between 06Z and 18Z Tuesday. Moisture tap will be pretty limited ahead of the vort with PWAT forecast to be generally around 1/2 inch or less. Nevertheless, showers will likely develop over the northern Sierra Monday night into Tuesday with perhaps a few extending down into the foothills and edge of the valley. QPF is mostly expected to be less than a quarter inch with perhaps 1-3 inches of snow accumulation above about 5000 ft.
Breezy north to east winds develop in the system’s wake on Tuesday and continue into Wednesday, and may lead to local elevated fire weather conditions where fuel conditions warrant.
Extended Discussion (Wednesday through Saturday)
Gusty north to east wind continues over portions of interior NorCal Wednesday into Thursday as high pressure continues to build inland.
Light wind expected Friday into Saturday. Dry weather with above normal high temperatures through the extended period.