Wednesday, July 29, 2015

Weather's long-range perils

Farmers Almanac sees brutal winter, and your guess is as good as theirs.

Weather's long-range perils

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We observed earlier this month that AccuWeather Inc. was climbing out upon an ultra-tenuous limb by issuing daily forecasts for the next 45 days.

So how's it going?

The consensus in the meteorological community is that beyond 5 to 7 days, forecasts begin to lose their usefulness, for a variety of reasons.

Cynics might say, don't you mean 5 to 7 hours, but, overall, meteorologists have made tremendous strides in short-term forecasting. We wish we could say the same for the long-range business.

AccuWeather's forecast for Day 6 of the 45-day outlook starting with Aug. 8 mentioned "a thunderstorm possible" in Philadelphia.

Day 6 happened to be Aug. 13, and we woul d have to say "a thunderstorm possible" didn't quite capture what happened. Downpours soaked the region that day, with over 2 inches of rain at the airport and over 6.5 in Coatesvillle.

Further out in time, the forecast for Aug. 27, as in today, called for a high of 77. It was 78 at the airport at 9 this morning, and 90 isn't out of the question.

The atmosphere is what the scientists call a non-linear chaotic system. Even with the most-sophisticated technology, it is unrealistic to believe that the savviest meteorologists are going to out-smart the atmosphere over the long run.

Which brings us to the The Old Farmer's Almanac. For whatever reasons, the Almanac's annual winter outlooks draw attention.

This year it appears to have generated more buzz than usual by calling for a brutally cold and snowy winter.

We're not sure how the Almanac arrived at this forecast, but anyone in the online hit-counting business can tell you that "snow" always draws traffic.

We'll wait for the more-serious forecasts, and even those we won't take too seriously.

 

Inquirer Weather Columnist
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Tony Wood Inquirer Weather Columnist
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