Significant winter storm moves through into Tuesday with heavy precipitation and damaging southerly winds producing flooding and mountain travel impacts. Additional storms move late this week and next weekend.
Rain moves through mainly this morning before tapering off this afternoon. Most of the valley is looking at around 1 to 1.5 inches today. Short break expected most of tonight before the second wave of the storm moves in early Tuesday. Winds are also picking up as surface pressure falls ahead of the approaching mid-level speed max are resulting in tightening gradient. Gusts so far have been in the 30-35 mph range across the valley with a few reports of 40-50 mph across the foothills. KDAX VWP has been holding pretty steady at around 40 kts at 1k ft above the surface. Expect we’ll see the peak winds occur around sunrise, or early this morning as the front approaches.
Still looking like some gusts of 55-65 mph will be possible resulting in widespread tree damage and power outages. Winds will drop off pretty quickly once the front moves through by mid to late morning.
Snow level radar show the snow level beginning to rise over the northern Sierra as the warm-sector move in. Caltrans cameras still showing moderate to heavy snow over the passes, and while the snow level will rise for a bit this morning, it’ll likely hold as snow across the higher passes. Several feet of snow accumulation are expected at the pass levels through Tuesday.
As mentioned above, we’ll see a break tonight before the second round of wind and precipitation moves in early Tuesday with the upper trough.
Precipitation will be more showery with several bands of showers and embedded thunderstorms expected. Overall QPF will be lighter, but individual locales may see heavier rain move through, so we’ll have to keep an eye on these for potential burn scar and other local impacts.
We’re likely to see somewhat of a break in precipitation Wednesday and Thursday, first as short-wave ridging moves overhead, and then the next upstream trough digs further offshore slowing the approach of the next frontal band of precipitation.
Extended Discussion (Friday through Monday)
Frontal system slow to progress inland Friday as it encounters high amplitude downstream ridge. Models differ with speed of progression, but eventually indicate widespread light to moderate precip over the weekend with some gusty wind.
Additional waves keep wet windy weather into early next week, but model differences keep some forecast uncertainty with timing of precip.