June 25, 2018 – Dry and cooler this week with high temperatures slightly above normal. Hot weather returns again next weekend with breezy northerly wind.
Discussion
Upper ridging that brought the hot weather has shifted east as upper troughing moves onto the West Coast. Increased onshore flow is advecting cooler air into Interior NorCal. Satellite showing widespread stratus along the coast extending inland through Delta. Fort Ord profile indicates marine layer has increased to around 2500 feet. Given depth of layer and strong wind through the Carquinez Strait, likely to see some morning stratus into the Southern Sacramento Valley. Strong onshore flow coupled with synoptic cooling will result in max temperatures this afternoon topping out about 10 to 15 degrees lower than Sunday. Highs forecast in the upper 80s to 90s for the Central Valley today with mainly 70s to 80s for the mountains and foothills. Although breezy conditions expected across portions to the CWA today, cooler temperatures with higher humidity will decrease fire potential.
Westerly flow aloft over Interior NorCal Tuesday, then broad upper troughing deepens over the area Wednesday into Thursday. Dry weather expected through the week as stronger dynamics with trough remain over the PacNW. High temperatures expected to be near to slightly above normal through Thursday with breezy southwest wind at times through the Delta and over higher terrain.
Extended discussion (Friday through Monday)
Upper trough shifts east Friday with continued slightly above normal temperatures. Strong upper high in the EPAC extends inland over NorCal Saturday and Sunday returning triple digit heat to portions of Interior NorCal. Slight cooling expected Monday as upper high retrogrades. Breezy northerly wind develops Friday and continues into early Sunday.