1). Michel sinking may conceal another city....(8)
2) Seasonally cold loses direction but gains strength....(6)
3) I’ve never seen an over cooked biscuit here....(10)
4) Might Michel sinking conceal another city....(8)
I was going to offer Scilly but can't have it without Isles of before or isles after. That would be chilly minus the h and add an s. Still does't explain lose the direction though.