We have a somewhat exciting forecast for the weekend if you like colder air, wind, and precipitation. Not a big storm this far south, but maybe enough for some light precipitation and some snow on the highest peaks!

Wednesday - Friday:

The sunny days and clear nights continue through Friday. Highs in the 70s at lake level. By Friday afternoon the ridgetop winds will start to increase as a trough pushes into the Pacific NW...

...along with a fairly strong storm and the first AR (atmospheric river) of the season.

Ridgetop wind gusts up to 40+ mph from the south-southwest by Friday afternoon. 

The Weekend:

Saturday will be mostly sunny again but slightly cooler. Highs may not get out of the 60s at lake level. The winds will be picking up for all elevations. Ridgetop gusts up to 60+ mph from the southwest and 30+ mph down to lake level. It will start to feel like a storm is approaching.

For Sunday we should see increasing clouds and winds throughout the day. Ridgetop winds could gust up to 100+ mph and to 50+ mph at lake level. The lake should become quite rough. Highs possibly breaking into the 60s Sunday morning at lake level but then dropping into the 50s during the afternoon as precipitation begins to push into the region with the cold front. 

By Sunday afternoon into Sunday evening, we will have the best chance of seeing some showers. The latest model runs show up to a few tenths of an inch of precip possible for the Tahoe Basin. Not a lot but the most we've seen in a while. We are on the tail end of a storm that will bring heavy rain to the Pacific NW.

Things will get interesting Sunday evening as snow levels fall behind the cold front. Any lingering showers Sunday night could see snow levels dip down to 8000-8500 ft. That means we could wake up Monday morning to a dusting of snow on the highest peaks above 8000 ft. Not uncommon this time of year but always an exciting sign that winter is approaching!

It should feel like fall early next week. Highs should only be in the 50s at lake level Monday and 60s for Tuesday. Overnight lows in the 30s and maybe 20s for the lower valleys. The winds should calm down by Monday behind the storm.

The long-range models show high-pressure building back in over the region through the weekend of the 25th.

That suggests we will transition back into a dry pattern with high temperatures closer to average or even above average some days. Likely back into the 60s & 70s by later next week. You can always check our mountain pages or mountain locations on our maps for forecasts for the higher elevations.

Fantasy Range:

The uber long-range models like the European Weeklies show that the storm track will mostly remain into the Pacific NW over the next 30 days. That is typical for this time of year until the jet stream strengthens and shifts to the lower latitudes during the winter.

That doesn't mean more storms won't dip far enough south into CA for some precipitation like this upcoming weekend, so we will keep an eye on that.

Seasonal Forecast:

We are continuing to look at the forecast for the upcoming season. I was looking through the analogs again with our southern CA forecaster Mikhail Korotkin last night. We are looking at several factors for the final forecast that will be out in October.

Some people have asked with global temperatures warming do analogs still work. Maybe, but with most of the seasonal forecast driven by sea surface temps, I think we can still look at those for how they could drive the overall patterns.

Right now, it looks like we are headed into a weak La Nina season. That by itself could be better for us than last year but not a signal of a wet winter for northern CA. The pattern should favor the Pacific NW again which is what most of the long-range climate models are showing for Oct-Dec. 

Like last season that puts us on the southern edge of the storm track. The season shifts either way but the majority of the weak La Nina seasons have fallen into the 90-100% of average snowfall range for the Tahoe region.

It does appear we have shifted back into an east QBO (quasi-biennial oscillation) phase which typically doesn't favor CA but seems to have less of a negative impact during weak La Nina seasons. We can see more downstream blocking and forcing of the jet stream farther south at times into CA.

The PDO (Pacific decadal oscillation) could go either way. It is almost neutral after being in the cold phase the last few years. There is a lot of warming in the northern Pacific right now.

We will have to see which way that shifts. A cold PDO phase historically favors us slightly more for snowfall in weak La Nina seasons, but warm PDO seasons don't shift the average much lower.

With the La Nina weaker than last season it is possible we see a more active MJO (Madden Julian oscillation) through the Indian Ocean and pacific this season which we didn't see much last season. That could bring more chances for AR events this season.

Unfortunately, the weather doesn't always correlate to what the analogs suggest based on the conditions going into the season. The last 2 weak La Nina seasons were polar opposites. 16/17 was a very wet winter and was a warm PDO/west QBO winter. 17/18 was very dry with a warm PDO/east QBO like we could see this winter...

The thing with the weaker La Ninas and El Ninos is that the other factors and the shorter-term oscillations can be more of a driver of the pattern during the winter. We can't forecast those patterns until we are in the midst of the winter season. Hence why seasonal forecasts are tough and rarely accurate on a consistent basis. But we continue to try and learn with more data and technology every year.

We'll share more forecasts as they are released and looking more in depth at what conditions are setting up and how they could affect our season as we go through the fall...

Stay tuned...BA