September 11, 2016 – Cooling trend through Tuesday with a slight chance of mountain showers or thunderstorms. Dry Wednesday through Saturday with temperatures warming back above normal by the end of the week. Red Flag Warning from 2 PM Monday to 11 AM PDT Tuesday for Eastern Mendocino NF-Eastern Portion of Shasta/Trinity NF- Northern Sacramento Valley to Southern Tehama County Line Below 1000 Ft-Northern Sierra Foothills from 1000 to 3000 Ft. Includes portions of Shasta-Trinity and Butte Units-Southeast Edge Shasta- Trinity NF and Western Portions of Tehama-Glenn Unit.
Trough of low pressure is deepening over the area today and helping to keep the delta breeze up today. This will result in cooler temperatures starting today. Highs may only be in the low to mid 80s for Sacramento region to the lower 90s for the north end of the valley. Moderate to locally strong delta breeze will continue into Monday morning and will help to bring a chance of low clouds into the Sacramento region Monday morning.
The low pressure area will continue to deepen over the west coast Monday and Tuesday. Monday and Tuesday’s temperatures will feel a bit more fall like than summer. The trough is mostly dry but will bring some chances of showers and thunderstorms along the crest Monday and Tuesday along with some breezy ridgetop winds along the crest late today and Monday. The best chance for thunderstorms look to occur on Tuesday from around I-80 southward and should contain some rainfall with them.
The low will move eastward Tuesday night and Wednesday with warmer and dry conditions but temperatures still remaining a little below seasonal normals for this time of year.
Extended discussion (Thursday through Sunday)
Warming returns to interior northern California as an upper level ridge from the eastern Pacific extends into our area. As a result, dry conditions and above normal temperatures are expected.