No it isn't.
The synonyms of the word bluster include: Blow, brag, and boast.
rave, rant, boast
boastfulness, arrogance, bluster, conceit, boasting
I don't think there is a synonym: forthcoming is not really a synonym as impending is generally only used of unpleasant or disastrous things about to happen.
impending
Menacing, foreboding, sinister, portentous, impending, apocalyptic, threatening, dire...
The duration of Feather Bluster is 420.0 seconds.
Synonyms for the word upcoming: approaching, forthcoming, future, imminent, impending, looming, nearing, next
The man gave a bluster about behaving well to the children.
Feather Bluster was created on 1958-05-10.
Meaning 1: deception, fraud, sham, pretence, deceit, bravado, bluster, humbug Meaning 2: precipice, bank, peak, cliff, ridge, crag, escarpment
The word bluster has quite a few synonyms - bravado, boasting, crowing, rabidity, and bluff are a few. Antonyms for the word bluster include - silence, quiet, stillness, and silentness.