Erin strengthens: when and why do we expect a turn northward?

We continue to monitor Tropical Storm Erin, which is located over 1400 miles east of the Lesser Antilles. Erin continues to move mainly to the west at about 17 mph and is expected to continue with this track through the weekend.

Most models continue to show that the system will stay north of the eastern Caribbean. Still, if you’re heading down to the Caribbean, expect stormy periods as Erin's rain bands will sweep through the smaller island chains, gusty winds, and the sea will be the most dangerous impact from the system. There’s also a risk for rip currents throughout the weekend across the eastern Caribbean.

The high-pressure system is moving Erin Westward, and as it moves off a pocket of cooler water, it starts to enter warmer ocean waters, which will allow the system to become stronger. Erin is expected to become a hurricane on Thursday and likely become a major hurricane by Saturday night or early Sunday morning.

Will Erin turn?

The good news is that Erin is strengthening during the rest of the week. This is usually not the kind of news that we wish for, but in this case, we want the system to become stronger as the odds of turning northward become greater. A weaker system would make it harder for the high-pressure system to continue guiding the system northward. Still, in this case, Erin is expected to gain major category status, which means that we will be a powerful system, allowing this north turn. Over the weekend, we forecast Erin to be turning especially late on Sunday, early Monday morning, and be well over 700 miles east of Miami, Florida.

The northeastern Lesser Antilles have a low chance for tropical storm force winds with the 5pm Wednesday NHC advisory.

South Carolina looks to stay safe from Erin's impacts. This will be a system that is expected to reach major category meaning at least a category three hurricane as it makes that shift northward and possibly passes near Bermuda. Considering it will be a major hurricane with very strong winds staying offshore, the seas will become very agitated; therefore, we expect large swells along the east seaboard from the east coast of Florida through pretty much the northeast. Beach conditions will begin to deteriorate early next week, and the seas are likely to remain unsafe for boaters or swimmers through much of the following workweek.

Irene Sans is an Emmy-winning, AMS-certified meteorologist (CBM, CDM) with more than 15 years of experience covering severe weather and climate stories across the U.S. and Latin America. A bilingual communicator and digital leader, she has delivered forecasts and science content for TV, radio, social media, and top weather platforms including Weather & Radar, WFTV, Telemundo, and The Weather Company. She has also served as Deputy State Meteorologist for Florida and consulted internationally on tropical forecasting and climate communications.