Hurricane season looks to be near-normal this year
Several factors are contributing to the near-normal hurricane outlook. Among them, sea-surface temperatures in regions where the Atlantic's tropical cyclones form, and conditions in the tropical Pacific that have an extended influence over weather patterns elsewhere.
Look for a near-normal Atlantic hurricane season this year.Skip to next paragraph
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That's the outlook from several groups who produce seasonal forecasts for the Atlantic hurricane season, which began Friday.
Here's a sampler:
• The National Oceanic and Atmospheric Administration anticipates a 70 percent chance that from nine to 15 storms will reach tropical-storm status and earn names. Between four and eight will become hurricanes. Of those, from one to three are expected to become major hurricanes, where maximum sustained winds top 111 miles an hour.
• At Colorado State University, where atmospheric scientist William Gray pioneered seasonal tropical cyclone forecasts, he and colleague Philip Klotzbach anticipate 13 named storms, five hurricanes, and two major hurricanes.
• Researchers at Florida State University give the season a 70 percent chance of producing 10 to 16 named storms, and from five to nine hurricanes.
• Tropical Storm Risk.com, a consortium of scientists and insurance-industry specialists based in Britain, is anticipating (in round numbers) 13 tropical storms, six hurricanes, and three major hurricanes.
The average between 1981 and 2010, the base period federal forecasters now use for determining above- or below-normal conditions, is 12 named storms a year, of which half reach hurricane status.
Several factors are contributing to the near-normal outlook. Among them, sea-surface temperatures in regions where the Atlantic's tropical cyclones form, and conditions in the tropical Pacific that have an extended influence over weather patterns elsewhere.
Tropical cyclones form over and feed off of warm surface waters. And while still warm by snow-bird standards, waters across the tropical Atlantic from Africa to Central America have posted their third-coolest May readings since 1995, when the current, relatively intense long-term period of tropical-cyclone activity began, notes Jeff Masters, a meteorologist and co-founder of the website Weather Underground. Sea surface temperatures are running only about a half a degree Fahrenheit above normal, suggesting that it may take longer for waters to warm enough to fuel tropical cyclones.
But he also points to a broad patch of unusually warm water running up the East Coast from Virginia through southern New England. There, average surface temperatures are running up to 7 degrees or more Fahrenheit above normal – perhaps setting the stage for sustaining or intensifying the strength of any hurricane that travels up the eastern seaboard.