Saturday, December 20, 2014

Forecasters predict hot summer, active hurricane season

On the threshold of summer, the record winter may have evaporated from the Philadelphia region's memory but not from the atmosphere's.

Experts warn that winter's mischief has left the Atlantic Ocean in a dangerously warm state, and that the next few months may be stormy, destructive, and costly along the Atlantic and oil-blighted Gulf Coasts.

It also may be quite hot around here. Some forecasters think that as summer ripens, nature will turn up the heat in the East with considerably more vigor than last year, and the state of the ocean might make hot spells more oppressive.

Summer temperature outlooks are perennially iffy, but the experts are far more confident about their take on the hurricane season.

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  • They say the Atlantic Basin, which includes the Gulf of Mexico and the Caribbean Sea, is about to have one of the busiest hurricane seasons ever.

    Odds are greater than usual, forecasters say, that New Jersey will take a significant hit from a hurricane.

    And even if hurricane winds and flooding rains spare the Shore and the rest of the region, they are likely to hit local taxpayers in the wallet anyway.

    Of more than $50 billion spent on federal disaster aid from 2005 to 2008, more than 85 percent was necessitated by hurricanes, especially Katrina. The 2010 season also is likely to add to the tide of red ink that has swamped the government's flood-insurance program, already $18.7 billion in debt. Combined, that comes to about $700 per U.S. household.

    In their outlooks, tropical-storm specialists point to an almost uncanny alignment of forces in the upper atmosphere, the tropical Pacific, and the North Atlantic.

    Hurricanes live off warm water, and the North Atlantic is a poor man's hot tub. "Right now it's very warm across the entire North Atlantic and the Caribbean Sea," said Gerry Bell, chief hurricane forecaster at the government's Climate Prediction Center.

    On Friday, for example, the water off Cape May was an almost-swimmable 67 degrees, about 5 degrees above normal. Warmer water would mean more water vapor, thus more humidity for those summer heat waves.

    More ominous, surface-water temperatures in the hurricane brewery - the subtropics between Africa and the Caribbean - are higher than they've ever been in the period of record, dating to the 19th century.

    That has everything to do with the winter of 2009-10 and the persistent air-pressure pattern in the North Atlantic that heaped more than six feet of snow on the Philadelphia-Washington corridor, Bell said.

    From January through April, that pattern disrupted the normal circulation over the Atlantic and virtually shut down the northerly trade winds that blow toward the tropics, Bell said. Those are the winds Christopher Columbus exploited in 1492.

    This year, without the cooling waters from the north, the tropical waters were able to simmer.

    The Atlantic already was primed because it has been locked in a so-called warm phase since 1995, the onset of the latest active-hurricane era. Researchers have found that active periods and lulls alternate in 15- to 40-year cycles directly tied to the warm and cool phases of the Atlantic.

    Some of the warmer summers on record in the East have coincided with the Atlantic's warm phase, but that connection isn't foolproof, said Todd Crawford, chief meteorologist with WSI Corp., a service in Massachusetts that serves energy interests. Remember, weather moves west to east.

    WSI is calling for a warm start to the summer with a crescendo of heat peaking in August. The outlook posted by Commodity Weather Group in Washington also foresees heat increasing in August, as does AccuWeather Inc. long-range specialist Joe Bastardi.

    In any event, Bastardi said, it will be much warmer around here than it was last summer, when temperatures were close to average.

    Along with other forecasters, he is much more certain about the Atlantic Basin hurricane season, which will begin Tuesday and last through Nov. 30. He is calling for up to 18 named storms, those with winds of at least 39 m.p.h.; the average total is 11. He foresees perhaps 11 reaching hurricane status, with winds of at least 74 m.p.h.; the seasonal average is 6.

    And Bastardi thinks he might be lowballing it. "I'm wondering if I'm underdone, rather than overdone."

    Other major forecasts are in the same ballpark. WSI predicts 18 named storms; Philip Klotzbach and William M. Gray at Colorado State University, which pioneered long-range hurricane outlooks, 15; and Tropical Storm Risk, a British service, 16.

    Bell and the National Oceanic and Atmospheric Administration are calling for 14 to 23 named storms. Bell said the upper range would depend on Atlantic waters' staying warm and the Pacific's cooling off.

    Last year, warm waters in the Equatorial Pacific, an El Niño event, generated strong west-to-east winds that sheared off developing storms in the Atlantic Basin. That helps explain why only three hurricanes formed in 2009.

    El Niño has faded, and it appears that its opposite, La Niña cooling, is taking hold. During La Niñas, the shear shuts off.

    Bell called the combination of La Niña, a warm Atlantic, and favorable upper-air winds "explosive."

    For obvious reasons, hurricanes are a huge concern in the Gulf region, said Ken Graham, a National Weather Service meteorologist with the New Orleans-area office. Gulf beaches could end up marinating in that spewing BP oil, particularly if a storm passes to the west of the spill, Graham said.

    But he said that the real danger was in the potential hurricane destruction, and that concentrating on the oil would be like focusing on the salad instead of the entree.

    "Everyone is talking oil," Graham said. "The bottom line is, the hurricane is going to get us."

    Bell said that although the signs were ominous, it was at least possible that La Niña wouldn't develop and that those Atlantic waters would cool a bit.

    But they are likely to remain tepid. In fact, the upper levels of the ocean all over the world have been warming in recent decades, according to a recent paper in the journal Nature.

    Though global warming appears to the driving force, the historical records are so wanting that it's not clear whether the warming is unprecedented, said Josh Willis, a scientist at NASA's Jet Propulsion Laboratory in California, one of the authors of the paper.

    The fact that the Atlantic waters are likely to stay warmer than usual would not be a welcome development for U.S. coastal residents and property owners.

    "It could be like the winter," Bastardi said. "I said it was going to be bad, and it was worse than bad."

     


    Contact staff writer Anthony R. Wood at 610-313-8210 or twood@phillynews.com.

     

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