What happens to old hurricanes?

Hurricanes get lots of attention from lots of people as they approach coastal waters and potential landfall, and this is generally a good thing. The media will latch on to these storms, providing frequent updates about the progress of the system. Reporters will be sent to the threatened areas, often to provide reports with the wind whipping through their hair and a backdrop of an angry ocean. This is not a good thing, as it indicates to the public that being in coastal areas as these systems approach is safe, when it really isn’t. Earlier this summer, a couple of people (including a young girl) were killed while watching the surf generated by Hurricane Bill at Acadia National Park, along the coast of Maine. They probably thought that since they frequently see reporters on TV in these locations that it must be safe. But I digress…

What I really wanted to discuss was the period of time after all the media coverage and hoopla have subsided. Typically, once a hurricane (or tropical storm) makes landfall, it will weaken and lose its tropical characteristics, and the National Hurricane Center will cease issuing advisories on the system. Its progress is then tracked by other divisions of the National Weather Service, who will continue to issue appropriate forecasts and warnings, but the excessive media coverage usually goes away. This may lead to the public concluding that the system is gone, or, at the very least, that it is no longer a threat. But even though the tropical cyclone characteristics are gone, sometimes these systems can continue to cause a variety of problems for several days (or longer) after the last advisory has been issued by the National Hurricane Center. 

A good case in point is the last Atlantic hurricane of this season, Hurricane Ida. This system formed in the southwestern Caribbean in early November and cut across Nicaragua and Honduras with a significant impact in much of central America, particularly El Salvador, then headed north-northwest through the northwestern Caribbean, passing through the Yucatan Channel and moving into the Gulf of Mexico as a Category 2 hurricane. From here, the system took aim on the U.S. Gulf coast, and although it weakened to a tropical storm before making landfall in Alabama, it still had an impact along the coast from the Mississippi delta to the Florida panhandle. As the system moved over land, it weakened and lost its tropical characteristics, and the National Hurricane Center issued its final advisory on the morning of Tuesday, Nov. 10, with the headline “Ida Becomes Extratropical…All Warnings Discontinued.” Within the advisory, interested parties were directed to other sources for information regarding the system moving forward, but as far as the media was concerned, the storm was over.

But it wasn’t. The low pressure circulation meandered east while continuing to weaken for a day or so, and ended up off the southeastern U.S. coast by later on Wednesday, Nov. 11. At the same time, an upper level low was evolving in the region, and this led to the surface low that had been Ida becoming stronger again as it meandered northeast toward Cape Hatteras, N.C., on Thursday, Nov. 12. The system then remained stationary for about 24 hours, then through the following 24 hours shifted only slowly east-southeast with a very slow weakening trend. Through this period, strong high pressure was anchored over the northeastern U.S. 

The effects of this system were widespread. First, because the system still had some tropical moisture involved, and due to the fact that it moved so slowly (or not at all at times), rainfall amounts were extreme from the southeastern U.S. all the way north into the mid-Atlantic region and into the Appalachian Mountains. For mariners, the slow motion of the system meant that winds persisted from the same direction for a long period of time over the water, allowing seas to become quite high. To the east of the Chesapeake region seas built to 35 feet at their peak. And, due to the position of the system, the wind direction to its north was east-northeast, which meant that the high seas in the Gulf Stream were short and steep, a very hazardous condition. Farther south off the Carolinas, as the system began to shift east, the winds became more northerly in the Gulf Stream and produced hazardous conditions there, and the very high seas generated farther to the north propagated into the region. 

Through this period, the Schooner Virginia with six eager Ocean Navigator School of Seamanship participants and Ocean Navigator editor Tim Queeney, their celestial navigation instructor, aboard were in Charleston, S.C., ready to depart for Bermuda. Wisely, Capt. Stefan Edick delayed Schooner Virginia‘s departure to wait for conditions to improve. Tim and his celestial nav students were hoping to see some stars, but even as the system weakened and moved east-southeast, they followed it toward Bermuda. Thus, the cloud cover was annoyingly persistent throughout the trip.

The message here is that often, even after a tropical system has moved inland, has weakened and lost its tropical characteristics, its impact on the marine community may be far from over.

About the Author 

Ken McKinley earned a bachelor’s degree in atmospheric science from Cornell University in 1980, and attended graduate school in meteorology at the Massachusetts Institute of Technology. After working as a meteorologist for nearly 10 years he founded his own meteorological consulting firm, Locus Weather, in Camden, Maine in 1991. 

A large portion of his business at Locus Weather involves providing custom weather forecast services for oceangoing yachts, both racers and cruisers. Ken serves as an instructor for the Ocean Navigator School of Seamanship, and also as an adjunct instructor at the STAR Centers for Professional Maritime Officers in Dania, Fla., and Toledo, Ohio, and for MITAGS in Baltimore, Md. He has also taught meteorology at Maine Maritime Academy. He resides in Rockport, Maine with his wife and two sons. Ken’s Web site is: www.locusweather.com 

By Ocean Navigator