Nice but boring weather expected this week through Saturday. Watching a cold trough that may dig into the Western U.S. by next Sunday.  That may push into our area from the east next Sunday into early the following week. Right now it looks like just colder air and maybe a few scattered snow showers if any.

We will keep an eye on that and I'll have a full forecast discussion for you on Tuesday.

The Upcoming Winter Season:

So far this fall I have stayed away from any seasonal snowfall forecasting. We are not big fans of seasonal forecasts since they are very hard to predict. We know that the forecast models lose a lot of accuracy over a 2 week period, so how can they predict anything beyond that?

I did an entire article on how far off the winter forecasts from weather outlets were last season, with many being completely opposite of what happened. I also have been posting forecasts for this season as they are released by different weather outlets this fall. We are seeing some with wet forecasts for CA...

...and some with dry forecasts.

So you can see why we aren't big fans of seasonal forecasts. However, each fall I do take a look at analog seasons based on the ENSO state (El Nino/La Nina), the PDO (Pacific Decadal Oscillation), and the QBO (Quasi-Biennial Oscillation). These are longer-term sea surface temperature and wind patterns that can affect the weather pattern during the winter season. 

There are also patterns like the IOD (Indian Ocean dipole) that can affect shorter-term winter patterns like the MJO (Madden Julian Oscillation). Those shorter-term patterns can't be predicted until we get within 2-3 weeks during the winter season. So for now just looking at the basic longer-term patterns.

For this season NOAA is predicting ENSO neutral conditions, a warm PDO pattern, and positive QBO pattern. Taking the seasons that had all three here is the precipitation anomaly map.

Which looks similar to the NOAA's Nov-Jan forecast for California...

Looking at the snowfall from those seasons is an average of 85% of average snowfall for the season. but that is a range from 64% up to 123% of average for the season. That may be because shorter-term patterns like the MJO can have a bigger influence on the pattern during ENSO neutral seasons. 

Even though this season matches up with patterns seen historically. The ocean temperatures are never exactly the same. The warm blob is south of Alaska similar to last season and the 2016/17 season. But the water along the equator was warmer last season colder in 2016/17. The water in the western Indian Ocean is also warmer this year.  Below is the comparison between 2018 (left) and this October (right).

So will we see less energy for the subtropical jet stream this winter, ridging in the northeast Pacific, and an MJO that is active in the western Indian Ocean and dies out in the eastern Indian Ocean? To me that seems to line up with the drier CA forecasts, but not mild. Maybe a colder winter with colder storms when we do get them? I'm going with 80-90% of average snowfall for my initial guestimate for this season.

Below is my score for the last 4 seasons...

You can see it's not easy to nail a seasonal forecast within 10 points. We have to rely on historical weather in similar patterns and try to line them up with this season. The forecast models just can't forecast accurately long-range thanks in part to the lack of global data and the butterfly effect, which I go into in another recent article on forecast models.

I am not sure how many forecasters post their scores. Probably too ugly for most to admit. Our company believes in transparency and accurate no-hype forecasts for snowfall, so I post my forecast variance after every storm for every ski resort. It compares the final forecast a day before a storm arrives to the final totals the day after a storm ends. I use absolute values so +2 for one mountain and -2 for another isn't "0" it's 2.

My 3-year average snowfall forecast variance is current at 1.7 inches. This also reflects the much more accurate data we can get from forecast models within a few days of a storm. No agenda here other than being obsessed with snow and trying to help everyone know exactly how much will fall at each elevation on each mountain.

We are continuing to work on more tools for you to hunt powder and many new features coming out soon! I'll continue to look at more patterns that could affect our winter snowfall as we get closer to winter, and I'll let you know as soon as I see storms starting.

Stay tuned...BA