You don't specify the size of the boat, but most of this will apply regardless.
A lot of the weather patterns during the winter have a southern component . Waves have a long way to travel up the Gulf of Mexico. As a result, the waves can come from hundreds of miles away. These waves / large swells give you a beam sea. If there is another weather pattern with winds from the North or East, you end up with a confused sea ( waves from 2 or more directions ). When the wave crests meet at your bow, the waves are much bigger. Doing this crossing in a confused sea is referred to as the washing machine as you get bounced around by waves from different directions. While cruising through these conditions can be done, you would need a very large boat to maintain 20+ knots, and the fatigue factor for 7 hours would be horrific.
Generally the weather window requires a number of days without winds from SE, S, or SW to let the seas calm down and 36 hours without significant winds from the NE or E.
As already mentioned, there is no GICW from Carrabelle to Tarpon Springs. Most Loopers wait at Carrabelle or Panama city for the window. Determining safe weather is very dependent on boat and crew. As you will be 75+ miles from land and the weather has been known to deteriorate, a forecast of 2' seas is the limit for many Loopers.
Ted
