Winter in the area seemed to be cruising along well on its projected course as one of those typical non-descript El Niño-influenced seasons.
That phenomena featuring slightly warmer than usual ocean temperatures is generally a signal for higher than normal temperatures and lower snow in the lowlands, retired Eastern Washington University meteorology professor Dr. Bob Quinn said back in late December.
The pattern started on the weak side but strengthened by the waning days of December 2018.
The strongest branch of the jet stream that delivers weather dives south primarily into California. That’s good news for the drought-stricken state. As of Feb. 15, snowpack sat at 175 percent of normal in the Sierras.
The question was posed to Quinn about the potential of Arctic Air outbreaks which could turn rain to snow. “We always do, but they will be short lasting,” he said.
“If our average snowfall is 50 inches I’ll be amazed if we even reach 30,” Quinn said. “My bias is towards a lower than normal snowfall winter.”
On the other hand, a given snow event over three days can ruin a forecast real fast, Quinn added.
Things were moving along as predicted through January where 5.2 inches of snow for the month brought yearly totals to a tad under 20 inches. Average is about 45 inches a year at the National Weather Service near Spokane International Airport.
But bang, here came February. As of the 15th, the 23 inches of snowfall for the month was fourth highest in the history of Februarys in the region, according to the National Weather Service.
“It goes to show that not every El Niño winter behaves like a normal El Niño winter,” Quinn said in a Feb. 11 interview. Even though the first part did a fine job of being warm and mild, obviously February is throwing a monkey-wrench in the whole system, he added.
What has transpired in the transition between warm and wet weather — the typical El Niño suspect — to cold and snow is the uncertainties that exist in one of the most complex climates in the world.
According to Quinn, the high pressure ridge which generally serves to deflect a lot of moisture from the Pacific Northwest recently moved further offshore some 500 miles. That allows the lush storm track to travel directly over the region — after a detour well to the north.
“When we were under the stagnant center of the high, we had all the cold air going down into the Midwest,” Quinn said. With the movement of that high further west, an upper level low planted itself over Vancouver Island.
So every 24 to 48 hours a storm system was on track to invade the region, punctuated by bouts of calm.
Between Feb. 9–11, systems that produced feet of snow in parts of North Idaho officially left over 13 inches at the National Weather Service office in Airway Heights. Local snowpack sits at over 100 percent of normal in the Spokane basin and 95 percent in the Idaho panhandle.
Also, on Feb. 11, the Climate Prediction Center reported that El Niño had weakened back into a “neutral phase,” meaning ocean temperatures had cooled to plus 0.4 degrees Celsius above normal.
A .5-degree bump signals a weak El Niño, 1 degree moderate and 1.5 strong. A La Niña occurs when temperatures drift in opposite direction.
The El Niño peaked in mid-December at about plus 1 degree Celsius, but has fallen in each month of 2019. The forecast in the coming month is for another drop in temps keeping things in a neutral phase through the spring.
What does that mean as the start of spring looms about a month from now on March 20?
If nothing else, adhering to the old axiom for Northwest weather, where if you don’t like things just wait 15 minutes.
Paul Delaney can be reached at [email protected].
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