More Major Storms Forecast for Intense Atlantic Hurricane Season

In its August update to the Atlantic hurricane season outlook, released today, NOAA's Climate Prediction Center projects an 85 percent probability of an above-normal season - up from 65 percent in May.

The National Oceanic and Atmospheric Administration, NOAA, issues its August outlook at the start of the peak months of the Atlantic hurricane season - August through October - and includes activity over the Atlantic Ocean, Caribbean Sea and Gulf of Mexico.

Streets flood and power is out in Welasco, Texas as Hurricane Dolly blows through. July 23, 2008. (Photo by Barry Bahler courtesy FEMA)

Forecasters say they adjusted their prediction due to atmospheric and oceanic conditions across the Atlantic Basin that favor storm development combined with the strong early season activity.

"Leading indicators for an above-normal season during 2008 include the continuing multi-decadal signal - atmospheric and oceanic conditions that have spawned increased hurricane activity since 1995 - and the lingering effects of La Niņa," said Gerry Bell, PhD, lead seasonal hurricane forecaster at NOAA's Climate Prediction Center.

The updated outlook includes a 67 percent chance of 14 to 18 named storms.

Seven to 10 of those storms are expected to become hurricanes, including three to six major hurricanes of Category 3 strength or higher on the Saffir-Simpson Scale.

These ranges encompass the entire hurricane season, which ends November 30, and include the five storms that have formed to date.

In May, the outlook called for 12 to 16 named storms, including six to nine hurricanes and two to five major hurricanes.

An average Atlantic hurricane season has 11 named storms, including six hurricanes and two major hurricanes.

Bell explained that conditions favoring a forecast of more hurricanes include "reduced wind shear, weaker trade winds, an active West African monsoon system, the winds coming off of Africa and warmer-than-average water in the Atlantic Ocean."

Another indicator favoring an above-normal hurricane season is a very active July, the third most active since 1886. Even so, said Bell, there is still a 10 percent chance of a near normal season and a five percent chance of a below normal season.

The NOAA forecast is in line with a new prediction of increased hurricane activity from meteorologists at Colorado State University.

Philip Klotzbach and William Gray said Tuesday, "We foresee a very active Atlantic basin tropical cyclone season in 2008. We have raised our forecast from our early June prediction. We anticipate an above-average probability of United States major hurricane landfall."

"We expect full-season Atlantic basin Net Tropical Cyclone (NTC) activity in 2008 to be approximately 190 percent of the long-term average," said Klotzbach and Gray.

"We have raised our seasonal forecast from what was predicted in early April and early June. This is due to a combination of a very active early tropical cyclone season in the deep tropics and more favorable hurricane-enhancing sea surface temperature and sea level pressure patterns in the tropical Atlantic," they said.

By the numbers, the Colorado forecasters differ somewhat from the NOAA predictions, but the general trend is the same.

"We estimate that the full 2008 Atlantic basin hurricane season will have about 9 hurricanes (average is 5.9), 17 named storms (average is 9.6), 90 named storm days (average is 49.1), 45 hurricane days (average is 24.5), 5 intense (Category 3-4-5) hurricanes (average is 2.3) and 11 intense hurricane days (average is 5.0)."

The probability of U.S. major hurricane landfall for the remainder of the hurricane season is estimated to be about 130 percent of the long-period average," said Klotzbach and Gray.

Hurricane Dolly damaged homes and businesses on South Padre Island, Texas. (Photo by Jacinta Quesada courtesy FEMA)

NOAA's hurricane outlook is a general guide to the expected level of hurricane activity for the entire season. NOAA does not make seasonal landfall predictions since hurricane landfalls are largely determined by the weather patterns in place as a hurricane approaches.

Five named storms have formed so far this season.

Tropical Storm Arthur affected the Yucatan Peninsula in late May and early June.

Bertha was a major hurricane and the longest-lived July storm on record, lasting from July 3 through 20.

Tropical Storm Cristobal skirted the North Carolina coastline.

Dolly made landfall as a Category 2 hurricane at South Padre Island, Texas on July 25 with 120 mile per hour winds and heavy rain.

And on August 5, Tropical Storm Edouard struck the upper Texas coast.

"It is critical that everyone know the risk for your area, and have a plan to protect yourself, your family and your property, or to evacuate if requested by local emergency managers. Be prepared throughout the remainder of the hurricane season," Bell said. "Even people who live inland should be prepared for severe weather and flooding from a tropical storm or a hurricane."

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