May 28, 2019 – Mainly late-day mountain showers and thunderstorms continue through the week. Temperatures warming to above average by the weekend.
Clear to partly cloudy skies with only a few lingering showers across the far northern Sierra Nevada as the latest short-wave slides south across the area. Current temperatures range from the 40s in the mountains to the 50s across the Central Valley and foothills.
Clearing skies with breezy north winds are expected across much of the area today as ridging briefly builds in at the surface and aloft. A few late-day showers or thunderstorms will be possible in the Sierra, but considerably less activity is expected compared to the past several days. Highs today are expected to be around 10-15 degrees warmer than Memorial Day across most of the area.
Temperatures will continue to warm gradually through the remainder of the week. Mainly diurnal showers and thunderstorms over the mountains will be on the upswing again beginning Wednesday as the next weaker closed low drops down from the PacNW during the second half of the week.
Extended Discussion (Saturday through Tuesday)
To start the month of June, a broad upper trough will sit along 120W longitude, generally centered over southern California. Embedded shortwaves will spin cyclonically, each being a potential impetus for foothill and mountain showers/thunderstorms.
Models continue to favor a gradual southward drift of this circulation during the weekend. Ultimately this would restrict convective chances to foothill and mountain locales south of Highway 50 on Sunday.
By early next week, the eastern extent of an offshore upper ridge may graze the region. A notable increase in temperatures is likely as highs move into the 90s across the entire Valley. Some readings approaching the century mark are possible over the northern Sacramento Valley. Slightly cooler numbers are expected over the foothills and mountains, mainly in the 70s and 80s.