The summers and the winters in the Northwest drastically vary based on weather phenomena specific to the region. Traveling winds, mountain ranges and ocean temperature all play a part. While the weather in the summer is slightly more predictable, the winter weather can be challenging to foresee, which is why forecasters are still uncertain of what this winter holds.
Rocco Pelatti, a forecaster from the National Weather Service, says predictions depend on the precipitation levels and water systems, with the most consistent summers easier to predict.
“Summer for the Pacific weather is less complicated, it’s one precipitation type, just rain,” Pellati said.
UI junior Clare Keogh witnessed the summer heatwave at an ice cream shop she worked at.
“I would see little kids with sunburns all the time or heat exhaustion,” Keogh said.
With the extreme summer weather, Keogh has been told to anticipate an extra snowy winter. Originally from Saint Maries, she is used to getting around in a lot of snow.
“It’s a rural area, so not all the roads get plows,” Keogh said.
According to Pellati, a chillier winter awaits the Northwest after October this year. She said one thing the region can expect in the coming La Niña winter is above-average precipitation and lower temperatures, meaning there could be more snow than what we’ve seen in recent years.
Professor of hydrology at the University of Idaho Timothy Link said the typical characteristics of the Mediterranean climate Moscow has included high-pressure systems during the summer months that avert most precipitation.
“As the air descends, it compresses and warms, which prevents precipitation,” Link said. “We’ll occasionally get a small amount of precipitation in the summer.”
Winter takes a turn into a low-pressure system, changing the precipitation levels.
“It’s called the Illusion low,” Link said. “It tends to spin off these sequences of wet, cold fronts.”
The current weather this fall is still reveling on the high-pressure system, according to Link, while slowly transitioning towards the low-pressure systems. As winter gets closer, Link said cold, moist air masses will move into the region from the northwest portion of the Pacific Ocean. Long winters are a result of the precipitation coming in during the later months of winter.
Depending on the combination of cold and moist the region receives, most of the precipitation will fall between November and April. However, snow can be the most unpredictable part of the winters.
“Winter is (precipitation wise) more active,” Link said. “I’ve seen snow as late as June, there’s a lot of variability in the climate here.”
Russell Qualls, an Idaho state climatologist and professor at UI, said much of the Inland Northwest’s climate is associated with how much contact areas there are with the Pacific Ocean. Wind blowing in from the west, or westerlies, greatly impacts weather in Moscow.
“We don’t get as cold as we would if we didn’t have that air moving in from the Pacific Ocean,” Qualls explained.
With the Cascade Range in Washington and Oregon, wind from the Pacific has to climb over the mountains before blowing into Idaho. The warm air that makes it over the higher mountain tops tends to cool and condense, resulting in precipitation.
Depending on the path it takes, this precipitation can end up further north, landing in the Spokane region as snow or as rain in Moscow.
Sometimes, air from the polar vortex, the Arctic’s circling cold air system, makes its way down to Idaho from the North Pole. This can contribute to the cooler winters Moscow has seen in the past.
During the summer, the westerlies calm down and Moscow tends to see less air movement as wind from the Pacific can’t make it over the mountain range. Without this air, the weather can be more dry and hot, similar to what Idaho saw this past summer.
Moscow saw little precipitation from March onward and saw record highs in heat. Temperatures in July reached over 100 degrees Fahrenheit for nearly two weeks. A phenomenon that could explain some of the excess heat is related to the lack of clouds.
Heat flux deals with the transfer of energy through a surface and can result in accumulated heat. Without clouds to block sun rays from the Earth’s surface, the sun’s heat collects in the ground.
The energy can be released through evaporation in a way that lessens the heat people feel, but there was not much precipitation this past summer so the high temperatures were a result.
“When you have a really dry summer like we did… a lot more energy is removed from the ground and causes the temperatures to be warmer,” Qualls said.
The amount of precipitation an area gets has many factors and is difficult to estimate. This is why winter weather can be harder to predict than summer.
“From a weather forecasting perspective, temperatures are an easier thing to forecast than precipitation,” Qualls said. “That gets a little bit harder.”
According to Qualls, moisture tends to accumulate with each individual storm. As an inconsistent trend, it is difficult to predict the yield every snowstorm will have. Being a few inches off in the prediction of each storm’s precipitation can add up quickly when considering how much snow a town will see that winter.
As precipitation tends to be more difficult to predict, Qualls could not say for sure what this winter will look like. Taking this with a grain of salt, Qualls said it’s looking to be more of a snowy winter.
“It was starting to look like it will be more on the La Niña side,” Qualls said. “If that kind of shapes up, we could start to see a bit of a recovery from the current drought.”
Michella Chowdhury and Haadiya Tariq can be reached at [email protected] or on Twitter @haadiyatariq