I was told the rule of thumb, especially over here on the shore is just add the wind speeds together.. lol.. its a wind tunnel over here. Its supposed to be north east today. I too am planning on going out at Cape Charles and going north a bit. I have a 19' renken and I think it will be a little calmer north. A few weeks ago, I went out of CC and went to fishermans island, the trip down was ok, 1-2 ft, NE wind. The way back was hard, I busted my nose, my bro in law hurt his wrist, my brother was sore, my boat was upset, its top wripped, gas filler wripped out of fiberglass, windshield brases broke. I learned my lesson. The mouth of Cherrystone creek is nice for the small boats. Need direction, let me know. Sandbars are trisky if you dont know the water.