April 26, 2021 – Scattered showers will linger over mainly the mountains today as the weekend weather system begins to move out of the area. Dry and much warmer weather returns beginning Tuesday.
Radar indicates a few lingering showers across the northern Sierra early this morning as the closed low centered over northeast California begins to slowly fill. Precipitation amounts overnight have been confined to the northern Sierra and generally range from a few hundredths of an inch up to around a quarter inch. Chain controls remain in place across some of the NorCal mountain highways, but have been recently dropped on I-80. Little if any additional snow accumulation is expected this morning, so the winter storm warning has been cancelled.
Trough lingers over NorCal today as another vort slides down from the north, and with daytime surface heating, will help to trigger a resurgence in deep convection this afternoon into this evening across the mountains. Shower activity will be scattered, but some localized amounts up to a quarter to half an inch will be possible with stronger cells. Minor snow accumulations will be possible across the higher peaks of the northern Sierra this afternoon into early this evening, but likely won’t present much impact to travel over the passes.
Highs today will remain cool across the mountains, but are expected to be around 5-10 degrees warmer across the Central Valley.
Upper level ridging returns to Northern California Tuesday bringing dry and warmer weather for the remainder of the week. Highs will return to the mid 80s to lower 90s after mid-week.
Extended discussion (Friday through Monday)
EPAC upper ridge remains dominant synoptic feature through the extended forecast period. Ridge weakens Friday into the weekend as relatively weak short wave trough moves through West Coast. Main effect will be a minor cooling trend, however high temperatures remain about 10 to 15 degrees above normal through the weekend. Temperatures trend up again early next week with some locally gusty north to east wind as upper ridge rebuilds.