La Nina may bring early snowfalls to parts of US

Big changes coming for Plains, Rockies mid-Autumn

It has been a hot and dry summer for most of the northern Plains and across the Rockies, and more of the same is on tap to start autumn before big changes arrive.

“We’ve seen a lot of cold air built up in northern Canada already,” Pastelok said, “but I do feel like the setup getting into October could be ripe for the northern Rockies.”

This flip of the switch in October will send the first waves of cold air pouring into the central U.S. to provide relief from the prolonged heat. The weather may go straight from summer — with heat and wildfires — to an early preview of winter during October.

This shift in the pattern will also bring some much-needed drought relief to the northern Plains with pockets of extreme to exceptional drought across portions of Minnesota, the Dakotas and Montana, according to the U.S. Drought Monitor.

However, this delay in the onset of autumn precipitation will be beneficial to farmers.

“We do feel like it looks favorable for the harvest across western sections of the Corn Belt, Minnesota, Dakotas, parts of western Iowa, because of the fact that we’re not looking at a lot of systems to get in during the time of harvest,” Pastelok said.

Farther south, the midseason shift in the weather pattern will be welcome for snow-lovers waiting to hit the slopes for the first time since spring.

“The skiers are waiting for this forecast to bring on the snow,” Pastelok said, adding that “mid-fall is probably the best shot.”

However, Pastelok warned that this will not open the floodgates for snow in the Rockies.

October is looking like a month for snow in the mountains from Idaho and Montana all the way down into Colorado, allowing some resorts to open on time despite current drought conditions, but the snow may let up come November.

Snowfall will wane “a little bit” late in the season, but that won’t dictate the entire snow season. Snow is predicted to come back again in the winter, Pastelok said.

A solid early-season snow base is not just beneficial for resorts and skiers, but also in the longer range when mountain snowmelt next spring and summer will feed streams and rivers that have been running below normal due to the drought.

Water reservoirs, such as Lake Mead, depend on rain and snowmelt for both recreation and hydroelectric power. With Lake Mead water levels at historically low levels, a bountiful winter is needed to help water levels rebound a bit following years of gradual decline.

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