April 14, 2021 – Shower chances continue today over the mountains with some high elevation snow possible over the Sierra. Warmer temperatures and dry weather late this week into early next week.
Discussion
Satellite imagery shows the closed low centered over the eastern Great Basin early this morning. NorCal remains on the backside of this system with radar indicating continuing showers over the northern Sierra south of Interstate 80. Northerly surface pressure gradients have weakened considerably, but we’re still seeing local north to northeast gusts of 20-30 mph over the northern Sacramento Valley, along the western edge of the valley, and over the foothills and northern Sierra.
The current ongoing showers may bring some minor snow accumulations to the higher passes south of Lake Tahoe early this morning before they taper off and move further south. The low won’t move much today and we’ll likely see redevelopment of showers and a few thunderstorms over the northern Sierra and southern Cascade Range by later this afternoon into early this evening. Otherwise, temperatures will be a little cooler today and less breeziness is expected.
High pressure begins to rebuild Thursday as the low gradually shifts east bringing a return of dry weather and slightly warmer temperatures.
Much warmer weather returns late in the week and over the weekend as the ridge moves in and light north/northeast surface flow develops. Highs will be around 10-20 degrees above average and will climb into the mid to upper 80s across the Central Valley by Saturday.
Extended discussion (Sunday through Wednesday)
Models in good agreement with EPAC upper ridging over the CWA Sunday. Solutions then diverge early next week. However GFS and ensembles support EPAC upper ridging remaining over NorCal through the extended forecast period. Forecast thus remains dry.
High temperatures upwards of 20 degrees above normal Sunday lowering to 10 to 15 degrees above normal by Wednesday.