Two B's first semester - explain or not?

How much will earning two B’s the first semester of senior year hurt your application if you had a 4.0 unweighted GPA through junior year and went from being ranked 1/400 to 15/400? Is it worth sending in an explanation letter to admissions or is it counterproductive?

it makes you look desperate to be honest.

To say what? It is unlikely that you will be able to write this in a way that will not come across as whiny.

It is doubtful that the difference between acceptance and rejection will come down to 2 B’s.

If your grades dropped for a reason such as a death in the family, illness, etc. I think it would be better to explain why it happened. If you just had a bad case of senoritis I think it would be better not to mention it.

Thank you for your comments. There actually was a family death 3 weeks before finals and a subsequent sickness, but, but after reading these comments I think it is probably best to leave it alone. Both drops were in harder AP classes anyways (AP Calc - B+, and AP Chem - B), so hopefully admissions will consider it a minor thing.