Dry and mild weather expected through the week. Light showers possible over the Southern Cascades tonight. Breezy north to east winds return Thursday into Friday morning. Cold morning lows with patchy morning frost possible over the weekend into early next week.
Discussion
Some high clouds moving over the region this morning will help to limit fog formation with some patches of dense fog still possible, mainly through the center of the valley. Another nice fall day is in store with highs in the 60s for the valley and foothills to the mid 50s to lower 60s for the mountains.
A very weak shortwave will move through the northern part of the state tonight. The interior is expected to remain dry with only a few showers possible over the mountains of Shasta County.
Behind the shortwave northerly winds will develop on Thursday becoming breezy to locally windy. The winds will be the strongest over the westside of the valley where a wind advisory may be needed. The winds will remain breezy to locally windy into Friday morning before gradually decreasing. For the mountains local strong gusts over the favored northeast to southwest ridgetops will occur in the 40 to 50 mph range Thursday night.
Lighter winds and cooler air over the region will result in seasonal daytime normals and cold nighttime lows with areas of frost developing.
Probability of temperatures in the valley going below 32 degrees ranges generally in the 15 to 35% for Saturday and 20 to 50% on Sunday.
Extended Discussion (Sunday through Wednesday)
Ensemble and cluster analysis indicates trough will move south over SoCal Sunday, as upper level ridge builds above it from the eastern Pacific over the Pac NW, extending into northern California.
A dry north to northeast flow will prevail over the area between these two features. Weak ridging will gradually build over all of California through mid-week.
Cold morning low temperatures with patchy frost/areas of frost continue through the extended forecast period with the coldest morning on Monday, then a slight moderation of lows during the week.
The National Blend of Models (NBM) suggests a 20 to 40 percent probability of low temperatures of 32 degrees or below in portions of the Valley on Sunday morning, and those probabilities and confidence for cold temperatures increase on Monday.
Be sure to plan ahead, and take the necessary precautions to protect pets, plants and people!