We know Scandinavians found America hundreds of years earlier. They even lived in North America.

There may have been Portuguese sailors who saw North America after getting lost, but since they didn't know where they were they couldn't explain where they had gone.

The major ocean current in the North Atlantic basically flows in a circle from Spain/Portugal, down the North African coast, then across to the Caribbean, before coming back along the North American coast and back to Iberia.