Windguru and other websites show why. With southern winds and a big swell, Simpson Bay is going to be untenable for boats. Most have fled inside the lagoon, as the winds are clocking and at some point every anchorage is going to be bad for next couple of days. The 3m south swell is going to wreak havoc.

Hit the "play" button to watch the fun: https://www.windy.com/?18.365,-62.501,8