Climate jury issues verdict on months ahead

By PAUL DELANEY

Staff Reporter

After deliberating over the past month, the verdict is in and the region will see its weather in the months ahead under the influence of a return to a La Nina weather pattern.

"A lot of the models are sort of in disagreement with each other," retired Eastern Washington University geography professor and climate expert, Dr. Bob Quinn' said earlier in the month. That prompted him to suggest keeping the warmer than normal ocean temps and generally drier winters with a weak El Nino.

But by last Monday the evidence proved otherwise. "The ocean temperatures definitely have switched to a La Nina," Quinn said.

And just as the calendar was about to turn officially to fall on Sept. 22, autumn-like weather appeared.

In the waning hours of Sunday, Sept. 17, the record string of 80 rainless days in our region officially ended with certainty. The record had stood for 100 years until first a trace and then .21 inches of rain fell across parts of the area on consecutive days.

That ushered in a span of wet weather where in five days, 1.21 inches of rain fell at the National Weather Service near Spokane International Airport. The average for the month is .67 inches.

The turning of the calendar page to autumn last Friday nearly coincided with the surprise release of a forecast from the National Climate Prediction Center in Maryland that backs up what Quinn predicts. After back-to-back-to-back El Nino winters (2014-2015 and 2015-16) plus last year's "La Nada," the outlook is for potentially colder and snowy months ahead.

An El Nino is the pattern that has, in the past, dusted us with just over 13 inches of snow in 2009-10, but came right on the heels La Nina's monster dumps in 2008-09 with just short of 98 record inches, or 2007-08 when nearly 93 inches fell.

The winter of 2016-17 earned Quinn's "tweener" term of La Nada and delivered 61 inches of snow. The El Nino produced nearly 34 inches in the winter of 2015-16, but just 17.6 during 2014-15.

"I'm looking at near normal snowfall which is 45–50 inches," Quinn said.

As for the long dry spell, Quinn was able to put a finger on why. Earlier he had suggested the likelihood of a few traditional summer thunderstorms that obviously did not materialize.

The pattern was simply too weak, he said. "Strong El Ninos in the past, have actually produced for us, a bit of a wetter summer," he added.

The normally very strong high pressure that forms out over cold water in the Pacific in the summer time was just a little weaker than normal.

"The end result is we didn't get the strong blasting marine pushes and sea breeze events that bring in the summer thunderstorms and burst of cooler air," Quinn said.

As was orchestrated recently by the swift change from dry to wet, the storm track is beginning its migration south from Alaska and British Columbia.

The storm track, Quinn explained, lives in the upper levels of the atmosphere about 18,000 feet where a strong river of air is that travels west to east around the globe.

"Imbedded within it is something called the Jetstream," Quinn said. "There's a narrower hose-like core of very high speed winds."

And as it migrates south, the track cuts off access to the 90-degree temperatures, too, ushering in autumn.

"Can we still get a short hot spell? Of course we can." Quinn said. "The 90s are now a thing of the past (for 2017)."

September and October will be populated with the usual small disturbances, not the seemingly eternal drenchings served up a year ago during October.

Paul Delaney can be reached at [email protected].