Forecasters were right when it counted

Weather forecasters are tired of being the butt of jokes.

Now, the joke’s on us.

They were dead on when they forecast a tremendous storm in November that caused record flooding and $24 million in damage in Snohomish County.

It happened again with predictions that a snowstorm would strike Snohomish County later in November. That storm knocked out power to 59,000 homes in Snohomish County and on Camano Island.

They were three for three when a giant windstorm blew through the region in December, knocking out power to more than 120,000 homes in Snohomish County and on Camano Island – and to more than 1 million in the region.

“There are still people who tell jokes, but I’m increasingly hearing people admit that the forecast is getting better,” said Cliff Mass, a professor of atmospheric sciences at the University of Washington.

Emergency responders who use weather forecasts to prepare for destructive storms agree that the National Weather Service and others who predict the weather are getting it right when it comes to major storms.

The accuracy has allowed them to position their people and resources ahead of time, better preparing them to tackle a weather event.

“You can pretty much go with what they’re saying,” said Brian Cobb, energy control superintendent for Snohomish County PUD. “They haven’t missed this year.”

Before the destructive Dec. 14 windstorm, the PUD had already hired dozens of work crews to come in and help get the lights turned back on, Cobb said.

Without that pre-emptive move, the utility would have had to wait for days to hire help because utilities all over Western Washington had snapped up all the available crews, which came from as far away as California.

“They arrived anywhere from the late evening prior to the storm all the way into the next morning,” he said.

Accuracy in forecasts is important, he said. Hiring outside crews is the most expensive part of responding to a storm, so you can’t just have people sitting around waiting for a storm that doesn’t come.

The U.S. Army Corps of Engineers used the early warning given by an accurate forecast to position more than 50 volunteers and prisoners along the Snohomish River in the hours leading up to the Election Day flood in November.

“We got a bunch of sandbags pre-positioned,” said Noel Gilbrough, assistant flood engineer for the corps. “It allowed us to get a really nice start.”

The levees all held, so no emergency repairs were needed.

Pinpointing the moment when forecasters started getting it right most of the time isn’t easy.

“It’s not like we haven’t been improving all along,” said Brad Colman, meteorologist in charge at the National Weather Service office in Seattle. “It’s subtle.”

The most obvious change is the science of weather modeling, which has rapidly improved, Colman said. Vast amounts of weather data are poured into better computer models and, more often than not, accurate forecasts are spit out the other side.

What does that mean?

Perhaps it’s easier to explain how the models have changed, Colman said.

The pure science of understanding weather has improved.

Computers are more powerful. Newer weather satellites are circling above us, feeding better data back into the supercomputers, Colman said.

“All of this has contributed to a much better and more skillful forecast process,” he said.

The resulting predictions are more precise longer into the future.

“We’re now really getting very, very useful forecasts five to seven days out,” Mass said.

He said it wasn’t long ago that forecasts were accurate for only up to a couple days, if that.

“It’s a different world when I first came through here in 1981,” Mass said. “We didn’t get any of these windstorms right; we didn’t get any of the snowstorms right.”

Mass and Colman say they still don’t get it right all the time, and over-hyping a forecast hurts credibility.

That leads to forecasters’ becoming the butt of jokes.

“We’re definitely doing better, but we’re still having our failures,” Mass said.

Forecasts are often off the mark when it comes to smaller, more localized storms, he said.

The models all predicted the windstorm that struck the region in December, but they all missed a localized rainstorm that dumped an inch of rain in less than hour on Seattle right before the wind started up.

“We couldn’t see it coming off of the ocean,” he said.

Mass said better radar coverage over the coastal areas east of the Olympic Mountains would have helped spot that storm.

Other times, bad forecasts are caused by human error, he said.

Multiple models showed a snowstorm hitting Everett at the end of February, but forecasters backed away from being too specific in their forecast and put out a more general warning.

Then 5 inches of snow fell in downtown Everett during rush hour on Feb. 28, causing gridlock.

“The models are getting so good that we’re starting to see more and more humans degrading the forecast,” Mass said.

Yet forecasters still need to exercise restraint because the models can be wrong.

In fact, exercising that kind of caution is what increases the accuracy – and the credibility – of predicting our atmospheric future.

“The role of the professional forecaster is evolving into being an interpreter,” he said.

Reporter Lukas Velush: 425-339-3449 or lvelush@heraldnet.com.