COEUR D’ALENE, Idaho — It will take three major low-pressure systems off the West Coast to adequately blanket Pacific Northwest mountains with snow this winter, Eric Snodgrass, principal atmospheric scientist for Conduit Ag, says.

As Snodgrass spoke last week at the Tri-State Grain Convention, Northern California was getting 20 inches of rain, a good start to the winter.

He showed satellite imagery of a “monstrous” storm just off the coast, spiraling toward the land. Wind speeds were beyond hurricane force, slamming into the West Coast, he said.

“You could put 12 Hurricane Helenes inside the storm system off your coast right now, that’s how big it is — absolutely massive,” Snodgrass said.

Snodgrass told the farmers he hoped the low-pressure systems would continue to develop.

“The best thing for all of you is to hate the forecast I’m about to give you because it’s going to be too much of a winter,” he said. “We hate the winters that just are raw, snowy and windy, until we get to May, and then we’re really happy that it happened.”

In the meantime, the region’s temperatures continue to edge higher, he said. Washington’s average summer temperature is trending 2 degrees higher than average. Most of that heat is in overnight lows, although daytime highs are a little warmer, too. 

“We’re trying to figure out what this means for all of you,” he said.

When it doesn’t rain in the middle of a growing season, except for a few “rogue, random” thunderstorms, evaporation rates are stressed.

“I need you to have a pretty nasty winter to fill all of this back up,” he said. “If we don’t, we go into the next growing season with problems.”

High pressure

High-pressure systems move moisture around in the atmosphere and push storm systems toward the Pacific Northwest.

“You don’t want that high pressure, called the Pacific High, to spend very much time at all over the Northwest at any given point throughout the year,” Snodgrass said. 

When it visits in June, July or August, that’s when high temperatures break records, he said. When it sets up in winter, that’s when all moisture transport shuts down entirely.

The Pacific High is encroaching on the West Coast more often during the summers, he said.

It’s better when high-pressure remains north of Hawaii, or better yet, the Bering Sea west of Alaska, Snodgrass said.

“That’s the best place for it if you need water,” he said. “Those are the kind of winters where you can’t stop the snow, that buy you 12 months worth of water.”

West vs. Midwest

The width of the U.S., about 3,000 miles, almost perfectly matches the width of the jetstream pattern, Snodgrass said.

“We have a rule of thumb in the Midwest: When you’re on fire, we’re happy,” Snodgrass said. “When we’re on fire, you’re happy.”

When the Midwest is under troughs of low pressure, the West is under the Pacific High. Farmers in the West prefer the Bermuda High over Champaign, Ill., he said. 

“For Midwest crop success, we want a Pacific High over the West all the time,” Snodgrass said. “You know why? The ridge that’s over you is not over us.”