UPDATE: Friday August 20: Tropical Storm Henri is currently about 400 miles southeast of Cape Hatteras, moving slowing in a WNW direction, with maximum sustained winds of around 65 mph. It is still a tropical storm but could become a hurricane by later today, Friday, and into the weekend.
Over the next 12 hours or so, the storm is expected to turn towards the north and accelerate, steered by a trough emerging from the Great Lakes to the west, and a building ridge to the east. It will then begin to intensify as it moves over the warm waters of the Gulf Stream and into an area of very little vertical wind shear. It will continue on a northerly track throughout the weekend, estimated to make landfall in the Maine area late Sunday, before turning towards the northeast and weakening as it hits cooler waters.
A short-lived pulse of swell will arrive at spots on the U.S. East Coast over the next few days, as the system brushes northwards. Around Cape Hatteras, for example, wave heights increase through Friday, peaking on Saturday, perhaps reaching six feet, and then quickly ramping down again. Local conditions are uncertain, but Saturday could see light winds. Around New England, wave heights pick up big-time on Sunday, but winds could be strong onshores. Further north into Canada, the swell picks up later in the weekend, with the possibility of some decent surf at south-facing spots.
EARLIER: Thursday August 19: Well, Fred's hardly faded from memory and already, we've got Tropical Storm Henri (and Grace!) spinning up and hoping to generate some solid surf for the east coast of the US. By the looks of things, Henri could even blitz up to New York as a Category 1 Hurricane.
We're also getting close to Hurricane season for that part of the world, and it had to start somewhere. MSW forecaster Tony Butt gives an early call out for this one: "Tropical Storm Henri, the eighth named tropical storm in the 2021 Atlantic season, is currently about 200 miles southwest of Bermuda, moving slowly towards the west, with maximum sustained winds of around 65 mph (needs to reach 74 mph before becoming a hurricane).
Spot guide: New York
"Over the next day or so, the system is expected to continue westwards with little change in strength due to fairly strong vertical wind shear. It is then forecast to gradually arc northwest, north and northeast over the following days, steered by an anticyclone to the north, and subsequently by a low pressure trough that pushes in from the west. It is also forecast to intensify as the shear decreases, and could become a hurricane by late Friday.
"There is still quite a lot of uncertainty in the models, but if Henri turns towards the northeast and tracks parallel to the East Coast of North America without coming too close to the coast, a short-lived pulse of surf could be generated accompanied by fairly good local conditions. Current forecasts for Rhode Island, for example, are showing five or six foot surf on Sunday, with winds from a northerly quarter."
We'll keep you updated throughout. But until then, track Henri using our swell chart, here.