Good afternoon, Beacon readers! If you’ve been enjoying these perfect summer-like days filled with sunshine, 70-degree temperatures and stagnant air in the Flathead Valley, it’s time to say goodbye as we skip ahead to winter this weekend.
The winds will pick up tomorrow afternoon across the Northern Rockies with widespread gusts of 30 to 40 mph from the southwest that are expected to settle by Friday night. A cold front is forecast to move across northwest Montana, bringing a 1- to 2-foot chop on Flathead Lake, according to the National Weather Service.
On Saturday, a low-pressure weather system from the Pacific Northwest combined with a cold, subfreezing air mass pushing south out of Alberta will shift the winds from the northeast and bring up to 40 mph gusts to the high country near the Continental Divide. The changing wind pattern could threaten docks and boats from Yellow Bay south and west toward the Narrows and Big Arm on Flathead Lake, which is currently 0.48 feet below full pool.
As cold and wet conditions move south on Saturday night, snow levels are expected to fall to the valley floor on the west side of the Continental Divide. While minimal snow accumulation is expected in northwest Montana, temperatures on MacDonald Pass near Helena could drop into the 20s, while up to 4 inches of snow is forecast in the Butte area, bringing wintry conditions to Homestake Pass and Georgetown Lake, according to the National Weather Service.
By Monday morning, temperatures in the Flathead Valley will drop into the 20s, while Polebridge temperatures could sink into the teens.
In a “very rare circumstance,” moisture remnants from Hurricane Rachel are forecast to track northeast from California and Nevada toward the Yellowstone and Wyoming area, according to the National Weather Service.
Hurricane Rachel is currently over the eastern Pacific, while her path is heading up the Southwest with the potential to bring 4 to 8 inches of rain to southwestern Utah and northwestern Arizona, boosting moisture in the Colorado River, according to AccuWeather.
While Hurricane Isaias – the Atlantic’s first storm to reach hurricane status this season – barrels toward the Gulf Coast, the Pacific is experiencing an unusually active hurricane season as other Godzilla El Niño-fueled systems shake up the global weather pattern. Sea levels off Southern California, for example, are expected to begin rising and remain elevated for months as a pulse of energy called a Kelvin wave travels up the West Coast, boosting the ocean’s height up to 18 miles off shore.
According to a discussion issued today by the NWS Climate Prediction Center, the potentially historic El Niño weather pattern is strengthening, and there’s now an 83% chance of a “very strong” event in the Northern Hemisphere this fall and winter. Sea surface temperature anomalies have exceeded 4 degrees Celsius in portions of the eastern equatorial Pacific.
El Niño emerges every two to seven years on average and is marked by warmer-than-average sea surface temperatures in the central and eastern Pacific Ocean near the equator. Winds that normally blow east to west over the Pacific Ocean weaken or reverse direction along the equator, causing water to build up in the eastern Pacific, according to the U.S. Department of Agriculture.
As the water and atmosphere heat up, the jet stream intensifies and shifts southward, shaking up the weather patterns across North America, bringing warm temperatures and minimal precipitation to the northern United States and more rain to the South.
Whether you’ve been here for decades or you’re new to the Flathead Valley, our reporting is here to help you feel smarter and in the loop about the issues most important to Northwest Montana. With your support, we can build a more engaged, informed community.
