The system does not yet have a name, but the National Hurricane Center said a tropical depression, the precursor to a tropical storm, formed Friday morning about 600 miles east of Jamaica. Forecasters expect it to intensify quickly this weekend before hitting Cuba late Monday into Tuesday and then barreling northward — likely toward the west coast of Florida. The storm could be as strong as a Category 2 or 3 hurricane when it approaches Florida Tuesday through Wednesday, though forecast strength is uncertain. As early as Tuesday, tropical storm conditions could develop over the Florida Keys and South Florida. The storm has the potential to produce “significant storm surge impacts, hurricane-force winds and heavy rainfall,” the Hurricane Center wrote Friday. “Residents … should ensure they have their hurricane plan in place and closely monitor forecast updates through the weekend.” The storm could be named Hermine or Ian, depending on whether this depression or another, just west of Africa, organizes first. It looks likely that this system will become the first hurricane to make landfall this year, and watches are in effect through the end of the weekend for parts of Florida and the Florida Keys. Eastern Canada braces for Fiona to be ‘a storm to remember’ Currently, the storm is about 72 hours away from making its first landfall in Cuba. In anticipation of the storm’s approach, National Weather Service offices in the central and eastern United States are launching additional weather balloons to pull in additional data to improve forecasts. As of Friday morning, the depression was about 500 miles east of Jamaica. Winds were around 35 mph, or below the 39 mph threshold required for the system to earn a tropical storm designation. An Air Force Hurricane Hunter reconnaissance aircraft was dispatched Friday morning to fly over and survey the fledgling system. In the satellite view, it is apparent that the entire storm is shifting to the west of a low-level vortex that has become the system’s de facto center of circulation. This is due to wind shear or a change in wind speed and/or direction with height. Easterly winds become stronger with altitude, so the system is somewhat tilted. This shear comes from the “outflow” or exhaust from Hurricane Fiona a few thousand miles to the northeast. Until this shear eases on Sunday, the tropical depression will be weak and unable to fully develop. Then, however, conditions will become much more favorable for intensification. See what Hurricane Fiona’s surf looked like, from the top of a 50ft wave On Sunday, the shear affecting the tropical depression will weaken significantly. At the same time, the system will slide under a clockwise rotating high pressure belt. This will help vent air away from the center of the system at high altitudes, enhancing upward motion within the developing storm and providing additional strengthening. This also means that more moisture-rich air in contact with the sea surface will be able to enter the storm from below. The waters of the northwestern Caribbean are too warm, full of thermal energy to fuel potentially explosive enhancement. That could easily help the system intensify into a Category 2 hurricane or stronger before it hits Cuba. For now, the National Hurricane Center is predicting landfall early Tuesday west of Havana. Before reaching Cuba, the storm is forecast to pass just south and then west of Jamaica, where four to eight inches of rain could fall and cause flash flooding and mudslides. As the storm moves across Cuba on Tuesday, some weakening is possible before the storm curves northeast over the warm waters of the eastern Gulf of Mexico, where it should regain some strength. While the Gulf is extremely warm, potential dry air and wind shear in the storm’s area could limit the intensity of the storm. However, the Hurricane Center predicts the storm will be a Category 3 hurricane Wednesday morning, with its center very close to the west coast of Florida. It’s too early to say exactly where along the Florida coast the storm might make landfall. There are still five days to go, and tracking forecasts this far ahead have large errors. There is still an outside chance that the storm’s track will shift west, more toward the central gulf, or toward the southern tip of Florida, or even east of the peninsula. After the storm possibly hits Florida, it could then move up the East Coast or just offshore, affecting coastal areas of the Southeast, Mid-Atlantic and even the Northeast later in the week. But there is much lower confidence in the forecast after Wednesday.
