March 17, 2020 – Showers, with mountain snow, will continue today. Below average temperatures through the week and may be accompanied with unsettled weather at times. Another strong winter storm will be possible early next week.
Discussion
Deep, cold closed low continues to move slowly south and is now off the coast of central California. Light to occasionally moderate precipitation continues along the main deformation zone across the northern half of the forecast area. Current temperatures are in the mid 20s and 30s across the mountains, while readings in the the Central Valley are in the upper 30s to mid 40s.
The closed low will transition to an open wave today and accelerate toward SoCal and the Desert Southwest. Mainly light precipitation will remain focused across the northern portion of the forecast area into this evening, and have extended winter weather products across the northern mountains until 11 PM. The far southern portion of the forecast area may see scattered showers and a few thunderstorms this afternoon as instability increases as the low pivots toward SoCal.
Cool and unsettled weather will continue the second half of the week as a weaker remnant low slowly fills, but temperatures will be slowly moderating. Any additional QPF will be light.
Extended discussion (Saturday through Tuesday)
Unsettled and cooler weather is anticipated this weekend into early next week as a another cold upper level low drops southward from the Gulf of Alaska. On Saturday ensembles and deterministic model runs show the low riding along the California coast, with light, mainly higher terrain precipitation over interior Northern California.
Confidence in the forecast for Sunday has improved in the low moving inland, spreading widespread wet weather. Rainfall and snowfall amounts are expected to be relatively light. More significant amounts are looking increasingly likely Monday and Tuesday as another Gulf of Alaska low drops down, though, and this could bring mountain travel impacts. The exact track of the low will determine intensity and amounts. Will have to closely monitor this system.