The most common and most likely answer to this crossword clue is the 6 letter word FUTURE
I've seen this crossword clue in The Guardian
F
U
T
U
R
E
Buddy explains!

The straight part
We know that "Days ahead" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case days ahead = future.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does FUTURE mean?
FUTURE noun- The time ahead; those moments yet to be experienced.
- Something that will happen in moments yet to come.
- Goodness in what is yet to come. Something to look forward to.
- The likely prospects for or fate of someone or something in time to come.
- (grammar) Verb tense used to talk about events that will happen in the future; future tense.
- An object that retrieves the value of a promise.
- A minor-league prospect.
- Having to do with or occurring in the future.
- Short for futures contract.