I don't think shooting on radar bearings alone is out of the question. Using the Dick O'Kane method, range is irrelevant. Using radar you can set the attack up on the map against what seems to be the juiciest targets and shoot blindly with an angled spread, just pick your range off of their track.
It sounds as though visually aquiring targets is way too dangerous.
Another option is to stay ahead of the convoy/task force and shadow and see if the weather improves. If it does, you should be in pretty good position to launch an attack. If not, the blind attack is still an option.
The opportunity sounds just too juicy to pass up.
Good luck.