Heat wave puts high pressure on weather forecasters

Meteorologists understand why we're going nuts about the weather.

First of all, it's really hot, at least by Seattle standards. We're not too much into extremes here.

A nice 80-degree day is just fine for us.

But 100 degrees, or, possibly, dare we headline it, a record-breaking 101 today?

Is that The Lovin' Spoonful in the background?

"Hot town, summer in the city ... doesn't seem to be a shadow in the city ... All around, people looking half dead ... "

True, according to Seattle Fire Department spokeswoman Helen Fitzpatrick, on Tuesday there were no 911 calls about heatstroke or any kind of heat-related problems.

Still, this is the town about which weather forecasters have a saying, "Never below zero, never above 100." So run out and buy another bunch of electric fans that'll end up in the basement.

Cliff Mass is a Seattle weather guru and University of Washington atmospheric-sciences professor whose blog — cliffmass.blogspot.com — has gained quite a following.

"I think there is something about the weather that reflects our natural awe of a natural world that is greater than us," he said. "People really enjoy a big storm. I think that all over the country, people are into weather. It's the number-one reason people watch the nightly news."

Plus, said Mass, "People love records."

But will a record be broken today or not?

The all-time high temperature of 100 degrees in Seattle was set July 20, 1994.

Official temperature records have been kept locally since 1894, and back then official temperatures were taken at the Federal Building in downtown Seattle.

So it's been 115 years of not one single 100-plus-degree day.

Today has put quite a burden on the TV weather forecasters.

Three out of four of them (Jeff Renner of KING, Rebecca Stevenson of KIRO, Steve Pool of KOMO) all said the record would be broken today and predict a high of 101.

Walter Kelly of Q13FOX went with 100.

Kelly said that who gets it right on the dot wasn't that big a deal — it's going to be hot whether it's 100 or 101.

What matters a whole lot more in forecasting, said Kelly, is getting it right during winter.

When it comes to predicting rain or snow, he said, "Who says 2-3 inches, and who says 9 inches?"

All weather forecasters — whether on TV or at the National Weather Service — have available to them the same computerized weather models.

They come with such acronyms as SREF (Short Range Ensemble Forecast) and can be fed all kinds of data, ranging from that provided by weather balloons that take a vertical sample of the atmosphere, to the gleanings from satellites.

But there is a point at which forecasting becomes more art than science.

"There is no model that is correct all of the time," said Dennis D'Amico, a meteorologist with the weather service. "You get to know the vices of a particular model. Maybe in a hot situation, it kind of underestimates the high. You mentally adjust for that."

Mass would like to see the TV forecasters, when, predicting the high for a day, give their predictions as a range instead of a specific number.

If a TV guy says it's going to be 75, said Mass, "That's not being honest. There is actually a lot more uncertainty in forecasts."

In trying for this honesty in weather reporting, the departments of statistics, atmospheric sciences, psychology and the Applied Physics Laboratory at the University of Washington developed a Web site application called Probcast.

It's aimed at the general public, and so psychologists were involved to make sure icons and wording used in the site were easily understood. The icons, said Mass, "were tested on hundreds of people."

Probcast takes seven different forecasts and combines them statistically, using the past performance of each.

For Wednesday, the application gave an 80 percent chance that the high would be between 97 to 107.

Mass himself said he thought the high would be 100.

KING's Jeff Renner said he'll keep using a specific number when predicting temperatures.

Trying to explain something like Probcast to a TV audience isn't exactly easy, he said.

And, he said, "The psychology of people is that they want a specific number."

Finally, here is a quote about the record temperatures.

"You get to feel what it's like inside a microwave. It's like from the inside out, you're just hot. It just becomes unbearable. You just never cool off," said John Faherty.

Is that how you were feeling?

Well, Faherty lives in Phoenix.

He's a reporter for The Arizona Republic and on Tuesday he was writing today's weather story for his paper.

Want a little perspective on the Seattle Heat Wave of 2009?

Here are some numbers.

Seattle: 79, 83, 88, 87, 81, 67, 68, 65, 74, 82, 85, 65, 64, 71, 81, 87, 90, 78, 77, 81, 87, 73, 69, 79, 86, 89, 94, 97

Phoenix: 103, 103, 107, 106,110, 109, 107, 107, 109, 112, 114, 115 113, 114, 107, 112, 114, 114, 114, 111, 103, 107, 107, 101, 108, 110, 115.

Those are the high temperatures at each city's main airports on the first 28 days of July.

For a time, Faherty lived in Portland. He knows Northwest weather.

"Tell those people," he said, meaning us Seattleites, "to keep a perspective. Enjoy your summer. The LOW this morning here was 92."

Erik Lacitis: 206-464-2237 or elacitis@seattletimes.com