A Tropical Depression May Form Within Days Off The U.S. Coast - Is Hurricane Season Awakening?

As I have written previously in Forbes, August for the Atlantic hurricane season is like the first big hill on a roller coaster. It is the time when the tropical cyclone activity really begins to ramp up to the peak in early September. University of Miami hurricane expert Brian McNoldy recently tweeted, "Over the past fifty years, 84% of the season's ACE (Accumulated Cyclone Energy) occurs after August 20." Accumulated cyclone energy (ACE) is metric that meteorologists like me use to express tropical cyclone activity and potential destructiveness based on wind speeds. As I write this, the National Hurricane Center is watching a system just off the coast of Florida that may develop and contribute to ACE for the 2019 season.

For the latest information on the storm, it is wise (and always recommended) to consult the National Hurricane Center (NHC). NHC's latest Tropical Weather Outlook on August 23rd says,

A tropical depression is likely to form this weekend or early next week while the low moves from near the coast of east-central Florida to offshore of the southeastern United States coast. Regardless of development, locally heavy rains are possible over the northwestern Bahamas and southern and central Florida through the weekend. * Formation chance through 48 hours...medium...40 percent. * Formation chance through 5 days...high...70 percent.

Currently, weather satellites and other meteorological data suggest that an area of week low pressure is just to the east-southeast of the Florida peninsula (graphic above). No immediate development is expected as the system slowly drifts toward (or over) the Florida peninsula. However, the conditions are favorable for development later in the weekend or early next week as the system heads back over open waters near Florida, Georgia, or the Carolinas. It is clear to me from the graphic below that ample warm water is available. Wind shear conditions (meaning not a lot of it) are relatively favorable in the region also.

If Invest 98L, the technical jargon we use for a system of interest, does develop to tropical storm status, it would be called Dorian. Dorian would be the fourth named storm of the Atlantic hurricane season. Tropical Storm Chantal, the third named storm of the season, briefly formed in the Atlantic this week but posed no threat to land. It is now winding down in the North-Central Atlantic.

There is also activity further out in the Atlantic Ocean. The National Hurricane Center points out in the same Tropical Weather outlook,

Showers and thunderstorms have increased since yesterday in association with a tropical wave located about 1400 miles east-southeast of the Windward Islands. Additional slow development of this system is possible during the next few days as it moves generally westward at about 15 mph.

There is a 20 percent chance of development as the storm moves across the ocean in the next 5 days. If you look at the satellite imagery from Friday morning (graphic above), there is yet another system near the coast of Africa. The graphic below shows a climatology of origin points (1851 to 2015) for tropical cyclone during the period August 21-31. The atmosphere is behaving as we expect it to and now is the time to start really paying attention if you live in hurricane-vulnerable parts of the United States or the Caribbean.