Could you tell me the difference between the fog rolled in and a fog rolled in? For example:
The fog rolled in and we couldn't see anything on the highway.
A fog rolled in and we couldn't see anything on the highway.
I checke the word in a dictionary, and it doesn't give examples of the word used with a when used in a literal sense. Strangely enough, I checked the word mist in the same dictionary , which is synonymous, and it gives examples with both a and the. Could you explain the logic behind using the in my examples.