Here we go with the 3rd storm in 10 days.

The winds are blowing hard this morning ahead of the storm as a strong jet stream has taken aim at northern CA. Ridgetop winds are already gusting close to 100 mph.

Precipitation is moving onshore in northwest CA this morning and will continue to push towards the Tahoe Basin through the day Tuesday.

Winds:

The winds will continue to be strong into Tuesday night. Ridgetop wind gusts over 100 mph are expected by this afternoon. Gusts from the south across Lake Tahoe of 50-60+ mph bringing large waves. The winds come down some on Wednesday but could still be gusting to 70+ mph over the ridgetops. The winds will finally start to come down through the day on Thursday.

Precipitation:

There was a slight slowing of the timing of the arrival of rain & snow. It may reach NW of the lake near Donner Summit between 4-6 PM, and the south side of the lake between 6-8 PM. It could also speed up slightly today. The heaviest precipitation is expected overnight into early Wednesday and then showers for Wednesday afternoon into Wednesday evening before ending Wednesday night.

The latest forecast model runs this morning have increased total precipitation amounts slightly with the average going up about 1-2 tenths. The range is 2.0 - 3.5 inches so still some discrepancy among the models. The GFS & ICON models put that 3-inch bullseye NW of the lake near Donner Summit. Then lesser amounts south and east from there. But still good spillover to the east side of the lake with 1.5 - 2.0 inches of total precip.

The total model average this morning is around 2.36 inches NW of the lake near the crest. Amounts fade south of the lake down to nothing south of Mammoth. Here is a look at the WPC's blended model for total precip through Wednesday night.

Snow Levels:

The snow levels are starting up around 9000 ft. this evening but fall quickly as the precipitation moves in. But only falling to around 6500-7000 ft. overnight, and then they could dip to around 6000-6500 ft. by Wednesday morning. They may jump up slightly midday Wednesday as precip lightens and fall back to 6000-6500 ft. by the end Wednesday evening. They fall below lake level Wednesday night with any leftover showers.

Snowfall:

As we have been talking about the last few days, the snowfall forecast around lake level in the 6000-6500 ft. range is going to be tricky. Heavy precipitation can drag snow levels lower at times, so we may see accumulations in some spots but not others. The best chance would be early Wednesday morning. 6500-7000 ft. may be a boom/bust zone. Then expecting mostly all snow above 7000 ft. on the mountains.

With the slight increase in the total precipitation average this morning, my snowfall calculator pushed the high end of the forecast up an inch. But I decided to stick with yesterday's forecast. The higher model runs only lends more confidence to my forecast, as I know with this storm I am slightly higher than other forecasts. For most storms, I'm a little lower.

The main reason for the high end of the forecast is for NW of the lake near Donner Summit where the 3 inch bullseye is on some models. Of course, if they hit 3 inches they would pick up more than my high-end as I am averaging out the models. The lower end of the forecast would be for areas to the south down to Kirkwood. Between 6000-7000 ft. we could see just rain up to the high end of the 6k forecast the higher up you go.

South of the Tahoe Basin, Bear Valley will be right near the cut-off line for the heavier precipitation. They could see the East Side amounts. Then Dodge Ridge looks to be in the 6-12 inch zone above 7500 feet. Mammoth is in the 3-6 inch zone this morning, but maybe an inch or two more if the heavier precip edges a bit to the south. I write a Mammoth Daily Snow every morning as well after I write this forecast, as well as the I-80 Daily Snow.

Thursday - Sunday:

Thursday through Sunday we are expecting mostly sunny skies. The winds drop through the day on Thursday and then should be lighter through the weekend. Highs in the 30s at lake level behind the storm Thu - Fri, and then the 40s for the weekend. About 10 degrees colder for the upper mountains. In dry air the temperature drops about 5-6 degrees for every 1000 ft. you go up, about double the change in moist air.

The trend on the models for the beginning of next week is for high pressure to remain in control through Tuesday, with the storm track staying to our north into the Pacific NW.

Then by the middle of next week, we may see a trough dig farther south into northern CA.

That may allow some weaker systems to drop far enough south into northern CA for the middle and end of Thanksgiving week to bring us some snow. Looking at the latest GFS model run, it only brushes us with a few flakes now from the middle of next week through the end of November.

We have been talking about how in a La Nina season we are going to be right on the edge of an active storm track to the north that can go either way. Especially early in the season, the snowiest La Nina months are Jan-Feb in the heart of the winter when the stronger storms have a better chance of digging farther south. We will keep watching the forecast because a slight jog south in the storm track could bring us more snow before the end of the month.

Fantasy Range:

The CFSv2 is suggesting a wetter pattern to start December...

...but the European Weeklies that came out yesterday were showing the storm track staying just to our north through most of December.

It's going to be a battle here in northern CA. Below average doesn't mean no snow at all though. Here is the European Weeklies for total snowfall through December...

What tends to help with West Coast roughing and the storm track dropping farther south during La Nina is an active MJO in the Indian Ocean. That is where the active phase is currently, but the forecasts show it weakening into the circle of death over the next 2 weeks. That forecast could be wrong, so we'll see. 

Of note this week as well is that the La Nina has weakened some. We saw warming in the ENSO regions near the equator, and we also saw some cooling near the West Coast.

The La Nina is still forecast to strengthen to a strong La Nina by the heart of winter in January. The water is also forecast to continue cooling off the West Coast and to stay warm in the Indian Ocean. All positive signs I believe, but we'll see... It's still really early in the season, only mid-November and it's snowing. Lots of fun ahead trying to will storms into northern CA.

Stay tuned...BA