Friday, May 25, 2012

More About May Tropical Systems

With Alberto already in the books, two systems in the Pacific already having developed, and another tropical system soon to follow in the Western Atlantic, our tropical season has already started with a bit of a bang...and on the Atlantic side, we're not even to the official starting point.

Sorta feels like the Atlantic hurricane season is like The Dictator in a 100 yard race with his own start gun based on the earlier than usual start.

May tropical cyclones are rare but not unprecedented.  There have been 40 tropical or subtropical storms that have developed in the Atlantic basin in the month of May, along with an additional 14 tropical or subtropical depressions.  The tracks of all of those tropical/subtropical systems is listed below...and it shows that the vast majority of those develop in the Western Caribbean or off of the Southeastern US coastline (whether it be in the Gulf of Mexico or in the Atlantic).  A few additional have developed in the Caribbean...but very few have developed to the east of the islands or in the Central Atlantic.  Able (1951) was one of the few to have developed farther out in the Atlantic and not only hang around for a while but also become a rather potent hurricane.



Very few of these have developed into hurricanes -- the only May hurricanes on the list occurred in 1889, 1908 (twice), 1951 (a Category 3), and 1970 (Alma).  None of those seasons were particularly noteworthy nor aggressive in numbers...those four seasons all had around ten total storms, with three of the years before  weather satellites were launched into space so getting accurate information about the whole of the tropics wasn't always the easiest to get since one had to rely on ship reports.  That said, the active early start (1887 and 1908 being the only two other times with two tropical systems out of the gate) is rarefied and is the beneficiary of having a trough off of the East Coast, warm ocean waters, and the right mix of ingredients to allow for tropical cyclone development.  That same trough is allowing for our thundery afternoons and the humid morass of air we've "enjoyed" the past couple of days.

Should "Beryl" develop from the tropical mess off of Florida's East Coast, it will be the first multistorm May in over a hundred years.