May 31, 2018 – Cooler weather today with warming trend returning for the weekend. Isolated showers diminishing today for Shasta county mountains.
Discussion
Good delta influenced breeze overnight with temperatures running cooler than 24 hours ago as trough of low pressure continues to slide westward across the area. Scattered to broken high level clouds ahead of the trough base were passing through the valley overnight with clearing behind the disturbance on satellite imagery.
Trough base will pass through the forecast area later this morning into the early afternoon, which will effectively end the chances for rain showers for the Shasta county mountains. While a stray isolated shower cannot be ruled out, chances will be reduced this afternoon as stable air encroaches.
High temperatures this afternoon from the cooler air mass will range between 5 and 15 degrees below normal for late May. Breezy conditions will continue, especially for the valley, through this afternoon and evening. Upper level high pressure will build heading into the weekend with temperatures warming back to between 10 and 15 degrees above normal by Saturday and Sunday with dry conditions.
Extended discussion (Monday through Thursday)
Dry weather will likely continue through the extended period. An upper level trough moving in to the Pacific Northwest will displace the west coast upper ridge inland during this time bringing cooler temperatures to the forecast area. Overall, daytime high temperatures Monday through Thursday are expected to drop to around normal for this time of year. Generally light onshore winds are expected each day.