10:45 AM | *Upcoming active period in the tropics bears close watching*
Paul Dorian
An active look to the tropics with multiple waves over the eastern Atlantic and Africa; infrared image courtesy University of Wisconsin/CIMSS
Overview
The climatological peak of the Atlantic Basin tropical season is around the middle of September with a usual ramp up of activity during the second half of the month of August. It looks like the atmosphere will be behaving as expected this year with an active period likely during the next six weeks or so and there are early signs for an important coastal threat as we approach the end of August or begin the month of September.
General warmer-than-normal sea surface temperatures (orange, red) in the Atlantic Ocean and Caribbean Sea and especially, near the US east coast; map courtesy tropicaltidbits.com, NOAA
Discussion
Sea surface temperatures are generally above normal in the all-important breeding grounds region of the tropical Atlantic Ocean extending from the west coast of Africa to the U.S. east coast. In fact, there are some pockets of well above normal water temperatures sitting off the U.S. east coast and over the Gulf of Mexico and this could play a role in any "close-in" activity during the next six weeks or so. Currently, there are multiple tropical waves across the eastern Atlantic Ocean including Tropical Storm Fiona and others over the continent of Africa. Fiona is fighting a lot of dry air and vertical wind shear and its prospects for significant intensification are not high. On it heels, however, the next tropical wave will likely have a more favorable environment for development and this is one that bears watching. All of these waves will move in a general west-to-northwest fashion during the next several days and some long-range model forecasts are indicating that there may be an important tropical system or two rather close to the U.S. Southeast or Gulf of Mexico coastlines at the end of August or early September. This is all in the speculation phase right now; however, given the time of year, widespread positive sea surface temperature anomalies, and the overall weather pattern, it all bears close monitoring over the next few weeks.
A forecast map from the GFS for the end of the month; map courtesy tropicaltidbits.com, NOAA
Amazingly, there has not been a major hurricane (i.e., category 3, 4 or 5) hit in the U.S. since October 2005 when Wilma made landfall in southwestern Florida during that wild tropical season. In fact, the state of Florida has not been hit by a hurricane of any intensity since 2005 and both of the streaks are very rare - if not unprecedented - in the record-keeping era. Let’s hope we can extend these streaks during the rapidly approaching heart of this year’s tropical season, but it may not be too easy. Stay tuned.
Meteorologist Paul Dorian
Vencore, Inc.