Long-range forecasts are rarely accurate and most of last season’s forecasts were incorrect. Also, these forecasts are for three-month averages. In short, don’t put too much stock in this forecast. OPENSNOW
Temperature: December, January, and February
The northern tier of the US has the best chance to experience colder-than-average temperatures. This also includes Canada, which isn’t shown because this is a forecast produced by the US government.
Precipitation: December, January, and February
Once again, the northern tier of the US (and Canada) has the best chance of above-average precipitation. Along with a good chance of below average temperatures, this could translate into above average snowfall.
Influence of La Nina
The maps above look similar to what we’d expect during a typical La Nina winter. During a La Nina, the ocean water temperature west of South America is colder than average and this affects weather patterns over North America (as well as other areas around the world).
Will we experience a La Nina this winter?
The latest forecasts show a 50-60% chance of experiencing a La Nina this winter. Those are not compelling odds.
What does this mean?
Lots of forecasters are jumping on the La Nina bandwagon, which points to higher-than-average snowfall across the northern US and into Canada. But, there is only a 50-60% chance of a La Nina, and even if there is a La Nina, it will likely be weak to moderate at best.
Last season, we experienced a strong El Nino, so most forecasters felt confident that our weather pattern would be similar to what we get during a typical El Nino year. But that turned out to be wrong.
Don’t place too much confidence in these long-range forecasts. The weather pattern that we expect from La Nina could easily shift a bit east or west compared to what the maps show above. Also, a three-month average of temperature and precipitation doesn’t tell you when to find the best powder days, so these long-range forecasts are of somewhat limited usefulness.