Update to 7.11.2011 blog: Above-Normal Hurricane Season for the Atlantic

On August 4, the National Oceanic and Atmospheric Administration (NOAA) updated their prediction for this year’s active Atlantic hurricane season, raising the number of expected named storms. We’ve already seen five tropical storms this season: Arlene, Bret, Cindy, Don, and Emily; none of which have made landfall in the United States.

NOAA’s Climate Prediction Center (CPC)–a division of the National Weather Service–is now predicting:

• 14-19 named storms (winds 39 mph or higher), of which
• 7-10 could become hurricanes (winds 74 mgh or higher), including:
• 3-5 major hurricanes (category 3, 4, or 5; winds 111 mph or higher).

These predictions are above the seasonal average of 11 named storms, six hurricanes, and two major hurricanes. There are several climate indicators that support this increased forecast; one of which is the possible redevelopment of La Niña (the girl)–an ocean-atmosphere phenomenon and the counterpart of El Niño (the boy). During periods of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean is lower than normal which typically produce more Atlantic and Gulf hurricanes. During periods of El Niño, sea surface temperature is higher than normal and its effects are often the reverse of those of La Niña. From 2010 to 2011, the last El Niño was followed by the strongest La Niña in a decade. This was widely blamed for the worst drought in a century in Texas and across the Southwest. Reduced vertical wind shear and lower air pressure across the tropical Atlantic are also climate indicators.

As these predictions change, we must continue to be aware of hurricane threats and prepare to take preventative actions when a storm approaches. Most coastal communities have emergency management agencies that have hurricane preparedness and evacuation plans as well as maps showing areas that could be flooded by a land-falling storm and evacuation zones showing areas that will be evacuated when storms threaten. These plans are supported by scientific data developed and provided by the Federal Emergency Management Agency and U.S. Army Corps of Engineers. Dewberry supports this effort by developing technical data and decision assistance tools for FEMA and the Corps of Engineers to help emergency managers make better informed decisions during periods of hurricane activity.

Are you an emergency management office who wants to develop a hurricane preparedness plan? We can help! Contact us for more information: [email protected].