NOTE: This blog was written by Matt Wiedert of the Yacht Warriors. Please check out his website for additional information on yacht charters in general.
Being weather-smart is a year-round necessity for charter crews. This edition is all about that - staying ahead of the game, no matter the season.While we'll delve into tides, currents, and navigating cuts in a future edition (essential for Bahamas-bound sailors), today we're focusing on the weather scenarios you're likely to encounter in the Windward or Leeward Islands outside of hurricane season.
Looking back at my first bareboat trip in the BVIs, I confess to being a bit casual about the weather. Caught up in the thrill of the journey, I assumed the usual 10-15 knot easterly winds and didn’t pay much heed to the forecast. In retrospect, I understand the potential hazards I overlooked. Imagine, for instance, the predicament if a northerly ground swell had surprised us at Cane Garden Bay at two in the morning.
As a saltier skipper today and a weather enthusiast, I’m more vigilant about the cruising conditions, ensuring safety and enjoyment for everyone on board.
Key weather features to pay attention to in the Caribbean
Christmas winds
These robust winds (15-30 knots), created by strong high-pressure systems in the Atlantic, can last for several days in the winter. They can provide exhilarating sailing conditions but also demand respect and skill. Make sure you are prepared to reef those sails! Northerly ground swells
This one can catch novices by surprise. From November through April, strong storms in the distant North Atlantic produce these swells that travel all the way down to the Caribbean.
These swells can affect northerly exposed anchorages, making them uncomfortable and potentially dangerous. Boats have been known to be thrown ashore from ground swells, so take caution.
The good news is they are extremely well forecasted. I'll cover that below.
These are some notable BVI destinations affected by ground swells:
Cane Garden Bay: if any ground swell is forecasted, we avoid CGB. Try Diamond Cay or other Jost Van Dyke anchorages instead
The Baths: while not an overnight destination, the mooring field will be quite rolly and swimming ashore from the dingy tie-off can be very dangerous. Make sure to check flag conditions.
Cooper Island: swells can wrap around into the mooring field, again, making this one unpleasant
Backwinding in anchorages
Here's how backwinding works:
Strong winds (~15+ knots) blow, in this case from the easterly trade winds in the BVIs
When the wind reaches this speed and blows over tall terrain (like many of the BVI islands), it doesn’t just blow straight over. A vortex is created and creates wind at the surface in the opposite direction of the trades.
So despite easterly trade winds, at the surface, you may experience a westerly wind which would push your catamaran towards the shore (see the picture above when we were anchored at Muskmelon Bay – the bow is oriented towards the west as a result of being backwinded)
Given how close you have to be to shore, it can be a concern at some BVI anchorages due to proximity to the shoreline – this can happen at White Bay, for example, when the wind is from the NE
Being backwinded can be acceptable if you plan for it and have enough swinging room to manage the phenomenon
Essential Weather Resources for Safe Sailing
To navigate these conditions, here are the tools and resources I've come to rely on:
NOAA Marine Forecast
If chartering in the Virgin Islands, this official weather forecast is crucial for understanding wind speed, sea state, and precipitation chances across different zones. It will also highlight any northerly swells that are forecasted.
Windy App
For visualizing the forecast, this app shows wind, waves, and more in an easily understandable format.
RadarScope App
This paid app provides high-resolution Doppler radar imagery, vital for tracking thunderstorms and other weather changes. You can pick up the Puerto Rico doppler in the Virgin Islands.
VHF and Radio Channels
Channels like ZBV 780 AM and NOAA WX3 and WX4 are indispensable for receiving marine forecasts in the Virgin Islands, when internet access is limited. For ZBV, here'sthe current marine forecast schedule:
M-F: 8:05am
Sat: 7:45am
Sun: 9:45am
Tropical Tidbits
If you're a weather enthusiast like myself, check out Tropical Tidbits for long range model runs. I use this one a lot during hurricane season.
Buoy 41043
This buoy, a few hundred miles north of the Virgin Islands, will show you swell conditions in real time.
