March 30, 2019 – Above normal temperatures and dry conditions will continue this weekend. Unsettled weather returns early next week with the potential for a wetter system late next week.
Discussion
Satellite imagery this morning indicates a ridge of high pressure building across interior NorCal. Thus, dry conditions and a gradual warming trend will continue through the weekend as ridging remains in control. Daytime highs are expected to be 5 to 10 degrees above normal with highs in the low to mid 70s in the Central Valley, and 40s to 60s over the mountains.
Upper ridging is expected to shift into the Great Basin early next week as upper trough approaches from the west. This system could bring widespread showers across the area Monday into Tuesday, with best chances expected Monday night into early Tuesday. Precipitation activity will move across the northern mountains by late Monday morning, and gradually spread southward by Monday evening. This doesn’t look like a very wet system, with heaviest precipitation extending from the southern Cascades through the northern Sierra.
Storm total precipitation amounts are forecast to be 0.5-1.25″ over the mountains, and less than 0.25″ in the Valley, except for locally higher amounts in the N Sac Valley. Snow levels are expected to rise above 7500 feet Monday, then lower to around 6,000 feet Tuesday. Snow accumulations of 4 to 7 inches could be possible. Lingering mountain showers should be tapering off by Tuesday evening.
Extended Discussion (Wednesday through Saturday)
Upper ridge over the west coast at the start of the extended period Wednesday will bring dry conditions most locations although models do spill some light precipitation over the northern zones as a shortwave passes through the Pacific Northwest. Ridging will allow for daytime highs Wednesday to climb to a little above normal southern zones with near normal temperatures under more cloudy skies to the north. Upper ridge shifts eastward into the Great Basin by mid day Thursday with a Pacific frontal system expected to spread precipitation over the forecast area during the day. ECMWF has been wetter with this system than the GFS but both have trended to lighter amounts over the last 24 hours. Snow levels remain high but a little below pass levels so even lighter precipitation amounts would have some mountain travel impacts.
Wet pattern forecast to continue into Friday as a warm frontal band sweeps across the north state bringing continued light precipitation and a little higher snow levels. For early April, an unusually strong Pacific cold front is forecast to push through northern California late next Friday and Saturday. This will be a fairly quick moving system, however, with what looks to be a fairly dry period early next week as stronger high pressure builds over the west coast.