First Tropical Storm Looms over Gulf—How Oil Spill May Intensify Hurricanes

June 26, 2010 (LPAC) —The National Hurricane Center said at 2:00 p.m. on Friday that it gives an 80% chance of the low-pressure center in the Western Caribbean, turning into a tropical storm. (It would be named Alex.) The definition of a low pressure zone is anything below 39 mile per hour winds; that or above, is a tropical storm.

In analyzing the likely effect of a hurricane on the massive oil spill, some meteorologists have pointed to the possibility of a phenomenon called explosive intensification. During hurricane season, the warm waters of the Gulf Loop Current can serve to produce a sudden decrease in the atmospheric pressure of a tropical cyclone, a phenomenon known as rapid deepening, or rapid intensification. The lower the pressure, generally the higher the winds and the more destructive the effect of a storm.

The fear is that if a significant amount of oil begins circulating in the Loop Current, the dark surface layer will help to warm the waters, contributing to rapid or even explosive intensification of any tropical cyclone passing over. The National Weather Service defines rapid deepening, or intensification, as a decrease of 42 millibars in less than 24 hours. If the cyclone drops at a rate of at least 2.5 millibars per hour for a minimum of 12 hours, it is known as explosive intensification. The fastest recorded rate of intensification was in 2005 when Hurricane Wilma dropped 53 millibars in less than 6 hours. That same year, Katrina and Rita also underwent extremely rapid intensification.

The current low-pressure center has formed between Honduras and Cuba, and is expected to be at the Yucatan Peninsula within a couple of days. It is not knowable yet, if this storm takes shape, where it might land on the U.S. Gulf coast. It is certain that storm winds and effects would drive oil-laden waters significantly inland in low-lying areas.

The Coast Guard says that a 5- to 7-day lead time is required for removal of the BP surface vessels, in case of any tropical storm. Recovery, burn-off skimming, and other operations would typically cease for 10 days during a storm episode.