Did a “Weak La Niña” Forecast Just Ruin Montana’s Winter?

New projections show the "La Niña" ocean current we were hoping to see to bolster Montana's winter snowpack probably won't be as robust as the first forecast.

But the National Weather Service says even with a "weak" La Niña, the weather pattern will deliver mountain and valley snow and consistently cold temperatures.

That could mean a much different winter than last year, when the Northern Rockies experienced a "snow drought" which impacted winter sports and summer water alike.

RELATED: Montana's Blackfoot locked in extreme drought

Get our free mobile app

What are the latest La Niña impacts for the Northern Rockies?

The latest winter outlook was released by the National Weather Service late last week, showing a lower probability of impacts from the change in the Southern Pacific to a La Niña current, which has a significant impact on weather in North America.

Brian Conlan, a meteorologist with NWS in Missoula says the chance of a La Niña winter has weakened to about 65%.

"That means there's a 35% chance that the La Niña does not develop at all," Conlan explains. "We also expect that once La Niña does develop, because we do have confidence it will continue through the winter at 70 to 75% probability."

More than just moisture

A La Niña track also has significant differences from other winters, when heavy snows can come out of the southwest, but when the mountains create storm "shadows" when the valleys receive limited snow. Under the expected scenario, the jet stream comes directly from the Northwest, which can result in heavier valley snow.

Conlan says typically, Missoula will receive multiple storms in the winter, usually averaging around an inch. But even in a "weak" La Niña year, that total can jump to storms that will dump 4 inches or more at a time.

"More than a foot of extra snow, 11 inches," Conlan says referring to the Missoula numbers. "16 inches extra for Kalispell, 11 inches for Butte, double the normal for Orofino (Idaho) and the trend continues for Salmon."

"So the core months really can have a lot more than normal snowfall. That doesn't mean it's going to actually happen. It's just saying it is a high probability it will."

Conlan says the jet stream could trend more from the northwest, which can bring more snow directly to the valleys, especially in Western Montana.

Will winter start sooner?

There are some early indications in might. Regional forecasts are now indicating our dry, warm fall has come to an end and that the valleys of Western Montana could see accumulating snow around Halloween.