March 9, 2018 – Showers possible over northern portions of the forecast area Friday. Warmer Pacific storm brings some rain and higher elevation mountain snow over the weekend. Series of wetter and colder storms move through Tuesday into Friday.
Discussion (Today through Monday)
High level cloud cover was streaming across northern California overnight ahead of a shortwave trough in the Pacific. Radar returns were clear across the interior, but some showers were moving onshore during the early morning hours.
Latest short term guidance depicts the showers currently along the coast will continue to slide eastward along the northern mountains later this morning through the afternoon hours. There will be some instability in the atmospheric profile, but confidence is not high enough to put thunder in the forecast.
The shortwave trough lingers across the area through the weekend with height falls as another larger trough begins to approach the coast. Scattered rain and mountain snow will continue across the forecast area. The larger system will approach and bring widespread chances for rain and mountain snow for the later part of Monday.
Extended discussion (Tuesday through Friday)
Wet and active pattern on tap for the remainder of next week. Slight timing differences remain between model solutions but in general, looks like system Tuesday, followed closely by another Wednesday, and a third Thursday into Friday. These systems will bring widespread precipitation to the area and add to the Sierra snowpack. Hard to pinpoint when the breaks in precipitation may be this far out, but likely won’t rain or snow the entire week. When all is said and done, rainfall totals in the Valley may be in the 1 to 3 inch range with upwards of 4-5 inches liquid equivalent in the mountains. Snow levels will start around 6000 feet for the first system Tuesday, dropping to around 5000 feet Wednesday, and down to around 4000 feet Thursday night as colder air continues to filter in. Periods of moderate to heavy snow will cause mountain travel issues. Details will become better resolved as we head into the weekend, so stay tuned to the forecast, especially if you have travel plans!