The storm could be as strong as a Category 2 or 3 hurricane as it approaches Florida Tuesday through Wednesday, though the intensity forecast is uncertain.
As early as Tuesday morning, tropical storm conditions could begin over the Florida Keys and southern Florida.
The storm has the potential to produce “significant impacts from storm surges, 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 throughout the weekend.”
The storm could be called Hermine or Ian, depending on whether this low or another just west of Africa organizes first.
It seems likely that this system will become the first hurricane to hit the continental United States this year, and watches are possible by the end of the weekend for parts of Florida and the Florida Keys.
As of now, the storm is still about 72 hours away from its first landfall in Cuba. Before the storm approaches, National Weather Service offices in the central and eastern United States launch additional weather balloons to attract additional data to improve forecasts.
On Friday morning, the low was about 500 miles east of Jamaica. Winds were around 35 mph, or below the 39 mph threshold needed for the system to earn the name of a tropical storm.
An Air Force Reserve Hurricane Hunter reconnaissance plane was dispatched Friday morning to fly and investigate the nascent system.
On visible satellite, it is evident that all storms are moved west of a low-level vortex that has become the de facto circulation center of the system. This is due to wind shear or a change in wind speed and/or direction with altitude. The easterly winds become stronger with altitude, so the system is tilted somewhat.
This shear originates from the “outflow”, or exhaust, of Hurricane Fiona a few thousand miles to the northeast. Until this shear relaxes on Sunday, the tropical depression will falter and cannot fully develop. Thereafter, however, conditions will become much more favorable for intensification.
On Sunday, the shear rocking the tropical depression will weaken markedly. At the same time, the system will slide under an area of high pressure rotating clockwise in altitude. This will help push air out of the center of the system at high altitudes, enhancing upward movement in the developing storm and promoting further strengthening. It 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 northwest Caribbean are very warm, filled with thermal energy to fuel potentially explosive reinforcement. This could easily help the system intensify into a Category 2 or greater hurricane before it hits Cuba. Currently, the National Hurricane Center is predicting a landfall Tuesday morning west of Havana.
Before reaching Cuba, the storm is expected to pass just south and then west of Jamaica, where four to eight inches of rain could fall and trigger flash flooding and mudslides.
As the storm crosses Cuba on Tuesday, some weakening is likely before the storm curves northeast over the warm waters of the eastern Gulf of Mexico, where it is expected to regain some strength.
Although the gulf is extremely warm, it is possible that some dry air and wind shear in the vicinity of the storm will limit the intensification of the storm. Still, the Hurricane Center predicts the storm will be a Category 3 hurricane Wednesday morning as it centers very close to Florida’s west coast.
It’s too early to tell exactly where the storm could hit along the Florida coast. There are still five days left and the runway forecasts this far in advance have big errors. There is still an outside chance that the storm’s track will move westward, more towards the central gulf, or towards the southern tip of Florida or even offshore to the east of the peninsula.
After the storm potentially 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 confidence in the forecast beyond Wednesday is much lower.
