Hurricane Leslie – East Coast Outlook

With a 75% chance of becoming a Hurricane in the next 72hrs, a size and intensity likely to generate significant swell and a track set to deliver surf to the entire Atlantic seaboard from Florida to Nova Scotia Tropical Storm Leslie looks more interesting than any storm so far for the US East Coast.

Swell in the 5-8ft@16 second period range hitting most exposed coastline. Tues 4th/Wed 5th

With conditions over the next 48hrs favourable to intensification and a 75% chance of Hurricane strength winds in that time frame a developing Hurricane Leslie is then forecast to encounter a cut-off low that’ll reduce the likelihood of further intensification but steer the storm in a favourable northerly direction at this stage reducing the risk of accompanying landfall and allowing greater time in the critical fetch window. Global models are forecasting that, while there won’t be further intensification after this time the system will increase in size and stall or slow for some period of time before moving north on a track that most likely takes it towards Nova Scotia.

GFS model prediction for a large slow moving storm on wed 5th August

With this scenario we have two almost distinct swell generation stages, that generated from this first 48+hrs that benefits from the storms favourable track and then a longer lived stage with the stalled storm large enough to generate surf making swell without the accompanying movement through the window normally required of smaller storms. With a good model consensus out to around 120hrs this forecast would mean that a Hurricane Leslie could offer a more prolonged run of solid mid sized swell than typical – perhaps 5 days or so of meaningful surf for most of the coast.

Surf Outlook

Latest Hurricane swell model data calls for good sized long period swell from Tues 4th / Wed 5th arriving in the 5-8ft@16 seconds range almost simultaneously along the coast with peak numbers in that range around the outer banks and at the lower end down into Central Florida – giving the potential for double overhead surf at spots that’ll handle that sort of size. Winds at this stage look light cross/onshore in Florida and increasingly strong and from the South or South West as you head up the coast, particularly from NC through to NY.

While your normal MSW forecast can under call hurricane swell we’d expect a slightly better correlation with this larger storm if things develop as the model predicts. For the latest Hurricane Leslie tracks and surf forecast click here.