'Follow the forecast week by week': B.C.'s weather outlook for fall and winter

This fall/winter is expected to be another La Nina season. However, Environment Canada says that is not enough information to produce a confident long range forecast this year. Here's why and what you need know about this up coming season.

According to the U.S. National Oceanic and Atmospheric Administration, B.C. is on La Niña watch.

Forecasters say there is a 70- to 80-per-cent chance La Niña conditions will develop this fall and winter. But meteorologists at Environment Canada say there’s still not enough information to produce a confident long-range forecast.

Here’s why, as well as what you need know about the coming seasons:

ENSO, the El Niño Southern Oscillation, is the primary climate phenomena used to determine long-range forecasts. ENSO conditions can be so strong, they can influence the atmospheric circulations, and thus weather, around the world.

ENSO can be classified in three ways: El Niño, La Niña or ENSO Neutral. To understand how ENSO is determined and how it influences global weather, check out this video.

ENSO is in neutral and has been since May. According to the NOAA, climate models are predicting La Niña conditions will develop sometime in September or October and will likely last through much of the 2021-2022 winter season.

Oceanic Niño Index (Niño 3.4 Sea Surface Temperature Anomalies)

Oceanic Niño Index (Niño 3.4 Sea Surface Temperature Anomalies)

NOAA Climate Prediction Centre

Luckily for skiers, La Niña seasons in the Pacific Northwest can typically produce above-average snowfall in the mountains, as well as cooler temperatures and lower freezing levels.

Luckily for drivers, it doesn’t always mean above-average snowfall in the valleys and at lower elevations.

Last year’s La Niña winter was a great example of this: B.C. had a healthy snowpack in the mountains and very little lower down in the cities.

Read more:
Eastern Canada headed for unusually warm fall that may feel ‘more like summer,’ experts say

So, why can’t we bank on another great ski season? The reason is the difference in the strength of the La Niña pattern.

Last year, it was strong, and this year, it is expected to be weak. This means its influence will be less and it opens the door for other short-term climate patterns to have a greater impact.

“Fall is generally the least predictable season and this fall is especially the case. We don’t have a lot of confidence in the seasonal forecast. The probability is very low right across the province,” Bobby Sekhon, a warning preparedness meteorologist with Environment Canada, said.

“The short-term patterns are going to be more important this year. People should be following the forecast week by week, almost daily.”

Sekhon said The Blob or the above average sea surface temperatures in the northern Pacific Ocean could have a larger impact on the weather in B.C., too.

Read more:
Return of ‘the Blob?’ New marine heatwave off B.C. coast raises concerns (2019)

The Blob has redeveloped and forecasters are keeping a watchful eye. It can have a warming influence on B.C.’s weather and can sometimes lead to the development of more high-pressure ridges. These typically mean drier, warmer, sunnier conditions, but it all depends on where the ridge develops.

According to the NOAA, there is a one in three chance La Niña may develop to be a strong La Niña sometime in the 2021-2022 winter period.

So there’s still hope for skiers.

© 2021 Global News, a division of Corus Entertainment Inc.

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