Forecasters predict unusually active hurricane season

Exceptionally warm ocean waters and favorable atmospheric conditions are expected to bring an above-average number of tropical storms and hurricanes to the Atlantic and Caribbean, national weather forecasters predicted Thursday.

The forecast comes as Florida braces for the remnants of Tropical Storm Emily, which has pounded the Caribbean in recent days with rain and winds above 50 mph. The storm weakened considerably Thursday, but is expected to bring some rain and winds to Florida over the weekend.

In its latest outlook, the National Oceanic and Atmospheric Administration raised the number of hurricanes to between seven and 10 — including three to five major hurricanes with winds of at least 111 mph. In May, the agency predicted six to 10.

Altogether, forecasters predict 14 to 19 tropical storms, which include the hurricanes. In May, forecasters predicted 12 to 18 tropical storms. The figure includes the five tropical storms that have already formed since the beginning of the season June 1. The season ends Nov. 30.

Forecasters point to the convergence of several factors in May that bolstered the increased predictions:

A combination of favorable oceanic and atmospheric conditions in the tropics has created a high-activity era since 1995. This, paired with the third warmest water temperatures on record, the possible redevelopment of La Niña, and reduced vertical wind shear and lower air pressure across the tropical Atlantic, has the area poised for a more active season.

“The atmosphere and Atlantic Ocean are primed for high hurricane activity during August through October,” said Gerry Bell, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center in Washington. “Storms through October will form more frequently and become more intense than we’ve seen so far this season.”

The seasonal outlook has proved beneficial in stating how many storms, hurricanes and major hurricanes will occur over the six-month hurricane season. But it does little in the way of predicting details of devastating storms, said Dennis Feltgen, spokesman for National Hurricane Center in Miami.

“The seasonal outlook cannot tell you when they’re going to form, where they’re going to form or, more importantly, where they’re going to strike land,” Feltgen said. “If that one storm hits you, it’s a really bad year.”

In 2010, the Atlantic and Caribbean experienced above-normal hurricane activity, but none made landfall in the United States.

The last hurricane to hit land in the United States was Hurricane Ike in 2008, which caused $10 billion in damage across Texas, Arkansas and Louisiana, the hurricane center said.

stephen.ceasar@latimes.com