Record Warm Ocean Waters Aiding Atlantic Hurricanes This Season

Published: September 3rd, 2010

Sea surface temperature departures from average (anomalies) for the
week of Aug. 22-28, 2010. Credit: IRI.

As we've demonstrated in this slideshow, the Atlantic Ocean is downright sizzling right now, with record-breaking water temperatures in some areas. This makes it more likely that there will be an above average number of hurricanes this season, including more major hurricanes of Category Three strength or above. And – as Hurricane Earl has demonstrated – it also increases the odds that major hurricanes will be able to maintain their intensity in areas they seldom frequent.

The above map of sea surface temperature anomalies from the last week of August shows the abundance of unusually warm water in the Atlantic, from the coast of Africa to southern New England. This is one of the reasons why the U.S. National Oceanic and Atmospheric Administration (NOAA) has predicted an above average hurricane season, and helps explain how Earl was able to stay so strong as it neared the Carolinas.

According to Weather Underground meteorologist Jeff Masters, Hurricane Earl became the third strongest hurricane to be observed so far to the north in the Atlantic Ocean when it maintained Category Four intensity on its approach to the North Carolina coastline earlier this week (it weakened steadily thereafter due to a combination of factors). On September 2 Masters wrote:

Only Hurricane Esther of 1961 and Hurricane Connie of 1955 made it farther north in U.S. coastal waters at a higher strength. Both storms had winds 5 mph stronger than Earl–145 mph. One other Atlantic hurricane was stronger than Esther and Connie at a more northerly latitude– the second storm of 1922, which had winds of 150 mph. However, this hurricane was far out at sea, north of Bermuda.

Warm ocean waters of about 78 degrees Fahrenheit or above are necessary in order for hurricanes to develop and strengthen, although other factors such as atmospheric wind shear help influence how strong a hurricane will become. This season, water temperatures in the Atlantic have been running extremely warm, and the unusually warm waters extend northward along the eastern seaboard to New England. Typically hurricanes weaken dramatically when they move north of Cape Hatteras, N.C., but the warm waters this season mean that any storm that travels along the East Coast may be able to maintain its strength for a longer period of time, barring other factors that can weaken the storm, such as strong wind shear. Interestingly, a story published today by the Associated Press says that global climate change may result in a greater number of hurricanes in the Northeast, due to warming ocean temperatures.