The tropical wave known as “Invest 93L” is closer to becoming a tropical depression. In his Tuesday morning blog entry, Weather Underground founder Dr. Jeff Masters says the factors are less than ideal for development. “The storm is now fighting high winder shear of about 20 knots. Water vapor satellite loops and the Saharan Air Layer analysis showed that 93L had more dry air to contend with than on Monday, with some tendrils of the dry Saharan Air Layer to the north encroaching into the circulation. Ocean temperatures have cooled since Monday, and are now marginal for development, about 27°C.”
The official forecast from the National Hurricane Center's webpage describes Invest 93L as “well organized” and gives it a 70 percent chance of strengthening into a tropical depression during the next 48 hours. The chance of becoming a tropical system rises to 80 percent over the next 5 days. The projected course is west or west-northwest at about 15 miles an hour. The NHC puts Invest 93L about 1500 miles west of the Lesser Antilles.
With Wednesday being the best guess from Masters on when 93L will become a tropical depression, the next most important piece of the puzzle is where it will go and when it will get there. According to Masters the computer models are showing it hitting the Northeast Lesser Antilles by the end of the week. Puerto Rico, the Virgin Islands and the Bahamas look like the most likely targets. As always, it's good to take forecasts for more than 3 days out with a grain of salt, but the consensus seems to be that the system will turn far enough north to stay off the Eastern U.S. coastline.
As far as the rest of the Atlantic there is nothing showing up on the NHC's experimental 5 day Graphical Tropical Weather Outlook that shows any potential for development over the next few days. Despite that bit of good news there's still no room for complacency. The Caribbean Sea and Gulf of Mexico can become active breeding grounds later in the season. When that happens residents in those coastal areas can have far less advance warning that a storm is coming there way than we've come to expect from storms that develop off the coast of Africa.