The National Hurricane Center (NHC) is monitoring two tropical systems in the Atlantic while Hurricane Erin tracks away from the U.S. East Coast but continues to produce dangerous surf and rip currents.
Tropical Wave Near the Leeward Islands
The most immediate system of interest is a tropical wave a few hundred miles east of the Leeward Islands that has become better organized. As of the 2 a.m. EDT outlook Thursday, the NHC gave the disturbance a 30 percent chance of formation within 48 hours and a 70 percent chance within seven days.
Located near 51° W longitude, the wave is producing a broad area of showers and thunderstorms. Conditions are considered favorable for development, and the system may become a tropical depression this weekend as it moves near or just north of the northern Leeward Islands.
The latest tropical weather discussion noted scattered convection ahead of the wave between 12° N and 21° N, along with fresh to strong easterly trades and moderate seas in the eastern Caribbean. Even if the system tracks north of the islands, forecasters cautioned that showers, gusty winds, and rough seas could affect St. Thomas, St. John, St. Croix, Puerto Rico, and the northern Leeward Islands late this weekend into early next week. Mariners should also prepare for building swells and rip currents.
Model Guidance
Forecast models, including the European ECMWF and U.S. GFS ensembles, largely support a track north of the Leeward Islands, though some solutions bring the disturbance closer. Both ensembles and the NHC maintain that development is likely within a week.
Disturbance AL99 in the Eastern Atlantic
The second system, designated Invest AL99, is a tropical wave located several hundred miles west-southwest of the Cabo Verde Islands. Scatterometer data shows a low-level circulation near 10.5° N, 31.4° W, though convection remains poorly organized.
The NHC gives AL99 a 40 percent chance of development within the next two days and over seven days. Environmental conditions are only marginally favorable, and the system is expected to encounter less favorable conditions by the weekend as it continues moving west-southwest at about 15 mph.
Hurricane Erin Update
While these systems develop, Hurricane Erin is accelerating away from the U.S. coast. At 5 a.m. EDT, the NHC placed Erin’s center near 34.2° N, 72.1° W, about 205 miles east-southeast of Cape Hatteras, North Carolina, and 440 miles west-northwest of Bermuda. Erin is moving north-northeast at 17 mph with maximum sustained winds of 105 mph, making it a Category 2 hurricane.
Erin is forecast to turn northeast and pass between the U.S. East Coast and Bermuda later today before weakening into a post-tropical cyclone by Saturday. Still, the storm continues to produce life-threatening surf and rip currents along the U.S. East Coast, Bermuda, and Atlantic Canada.
A tropical storm warning remains in effect from Beaufort Inlet, North Carolina, to Chincoteague, Virginia, including the Albemarle and Pamlico Sounds. A storm surge warning is in place from Cape Lookout to Duck, North Carolina. Bermuda remains under a tropical storm watch.
The hurricane’s expansive wind field extends tropical-storm-force winds outward up to 320 miles (520 km). Swells will continue to affect the Bahamas, Bermuda, and the U.S. East Coast before the system transitions into a post-tropical cyclone later this week.
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