Originally Posted by Cheechako
Generally, You are looking for a weather
window when the wind is clocking south of east or even west...
When planning a crossing of the Gulf Stream
in a small boat, the wind speed and direction are probably the most important factors in deciding when to cross.
Generally, look for winds of 10-15 knots or less, and (as Cheechako said) NO Northerly component in the wind.
winds dominate the weather around the Gulf Stream, generally blowing 12 - 25 kt in Winter, and 5 - 15 kt in summer.
Weather fronts disturb the trades, tending to go SE, then S, W, NW and finally N (clocking). Obviously, when it is blowing out of the North the cold front has arrived.
If it is a slow moving front, or for a fast moving boat (like yours) it is possible to leave when it is blowing out of the South. As you make your crossing the wind will be on the beam, and then it will clock favourably and be on the stern as a sailboat makes it's passage. There is a possibility that the wind will back to SE or E for a while before is swings quickly to the North.
With all of the prediction models, look for consistency in the prediction as it moves from the three or four day to the 24-hour prediction.
What you really want to find is a nice fat high-pressure dome sitting right on top of the Northern Bahamas
with isobars spaced wide apart. This is fairly common in the summer months.