What do I do now

[joho]

It is summer -40 and I intercepted a small out going convoy southwest of Ireland only ecorted by a destroyer and a corvette.
Weather is fine 2m/s wind, light fog, no rain visibility good. It is 9 in the morning and I know its a no moon period. Perfect conditions for a surface attack at night.
So I start to trail wating for darkness, suddely 4 houers later out of the gray heavy fog, medium rain 7 m/s wind visibility 0. I know they are out there of my port side, I just cant see them, I can hear them though. Do I continue the trailing hoping that the weather gets better or do I steer 45° port and begin a submerged attack?

Any suggestions?

Im playing GWX 2.0 Commander. Type VII.