not sure if this is related but could be a reason why..
Tree surgeon Hiroyuki Wada told Japan's NHK news agency that the culprit is the extreme weather that plagued the island nation throughout the summer, specifically the major typhoons that lashed the country.
The Somei-yoshino variety of cherry blossom develops its buds during the summer months, Wada tells the state broadcaster, but the trees' leaves prevent their blooming by releasing a hormone that inhibits their growth.
Because many of the trees lost their foliage during the summers' violent storms, there has been nothing to stop the buds' development. This, coupled with warmer temperatures following the storms, has resulted in the earlier-than-planned blooming.
While the 350-or-so sightings this fall are considered to be aberrations, earlier-than-expected blossomings have been noted before. In 2013 unusually warm weather prompted sakura blooms 10 days earlier than average and 15 days earlier than the previous year.
read more:
https://www.cnn.com/travel/article/japan-typhoon-cherry-blossom-premature-blooms-intl/index.html