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Monday, January 25, 2010

Rofflcopter Of The Day - Origins Of The Chicken-Little Forecast

Jerry sends this:
Some interesting info concerning that alarmist weather forecast that was making the rounds a while back:
HA! HA! HA! That is SO funny! What's that they call it? A rofflcopter!

Mr. Swain was deeply impressed about the potential of the approaching storms, and the storms have proven strong. Unfortunately, he chose florid language to convey his excitement, which conveyed the impression that the storms would be nearly-unprecedented in strength. We all do the same from time-to-time. We just need to be careful. Weather forecasters are out there on the bleeding edge. Weather forecasters, in particular, need to be careful:
As a rule, I like rain. Unlike many Californians, I could live happily in Seattle, curled up with a book in a coffee bar while the deluge swirls around me.

But as a longtime Mercury News reporter, I helped cover the great storms of 1982, which caused serious mudslides and vast chaos in the Santa Cruz Mountains.

That's made me more aware of the dangers of weather and of certain words used by forecasters. One of those words is "pineapple."

The "Pineapple Express," as it's often called, is no sweet breeze. The media uses it to describe a strong and punishing weather front headed toward the Pacific coast from Hawaii.

The storms of 1982 reflected the Pineapple phenomenon. And so when I came across a widely distributed forecast on the Internet that mentioned the word, I stood straight up.

Armageddon

The author sounded an alarm we know too well. He wrote that the models were virtually unanimous in identifying a reloaded jet stream with a "persistent kink" — the nexus of a storm front — 2,000 to 3,000 miles to our southwest.

"This is a truly ominous pattern, because it implies the potential for a strong Pineapple-type connection to develop," the author wrote, predicting copious warm rains beginning this week.

"The potential exists for a dangerous flood scenario to arise at some point during this interval, especially with the possibility of a heavy rain-on-snow event," the writer continued.

Adding credibility to the threat was the name at the bottom. On blogs and message groups, the Jan. 12 memo was attributed to Samuel Y. Johnson with the U.S. Geological Survey in Santa Cruz. Here we go again, I thought.

Johnson, however, did not write the memo. From Japan, he wrote to say he was simply forwarding a forecast sent to him by someone at Cal Fire.

The people at Cal Fire told me the memo did not originate with them — and instead was lifted from a Web site, www.weatherwest.com, which is run by a University of California-Davis junior, Daniel Swain.

In part because many people believed that Johnson was the author — and in part because we are often willing to accept the worst — the prediction went viral.

Fear and loathing

I'm willing to bet it caused serious fear and loathing in Bay Area households — and a rush on sandbags. "I've never seen a weather document circulated like this," said Jan Null, a certified meteorologist with Golden Gate Weather Services.

The forecast, however, was wrong — which, let's face it, is an occupational hazard rather than a plot against humanity.

Null thinks the author misjudged the storms of the last week, which featured breaks rather than the continuous pounding of a Pineapple-like storm.

"There's a lot of misstatements of information," Null said. "The pattern we've had this past week is not a Pineapple connection."

Since 2000, Null added, there have been six other periods with the level of rain that we've had over the last week.

What does UC-Davis student Swain have to say about this? He acknowledges Null is right.

"The way the pattern actually evolved was somewhat different than it might have evolved," he told me. "What I was referring to was a potential for a warm pattern to develop over the next week. Right now, there's no indication of any Pineapple Express storms."

But even he is bemused by how widely the misattributed forecast spread. "It was kind of mind-boggling," he said.

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