Anyone going down soon should look at this Yikes!
A few summers ago we went to the SVI aboard a Lipari 41 from CYOA.
It looked just like that!
Had me watching the weather pretty close!
We had one do a near-miss, about 200 miles north of STT.
We had some pretty strong thunder-storms with winds of 40-knots.
I also use nhc.noaa.gov for tropical storm tracking while I'm down in the VI.
This time of year tropical storms between Africa and the VI are very common. Most charter companies are not going to allow you to cancel or delay your trip unless a direct-hit of a named hurricane is withing 24-48 hours of STT. It's pays to keep in close touch with your charter company if you have any questions.