Two weather forecast companies issues Cherry Blossom Blooming forecast across Japan.

Weathernews expects Cherry trees in Hirosaki castle Park will bloom on 18th April at present.
https://weathernews.jp/s/topics/201801/170085/ (Japanese site only)

Tenki.jp expects cherry trees in  Hirosaki will bloom on 17th April at present.
https://tenki.jp/sakura/expectation/  (Japanese site only)

Full bloom of cherry trees in Hirosaki castle park is expected in late April(22- 28) at present.
Full bloom of The cherry lined road of Mt.Iwaki is expected in early May.

Hirosaki castle park

The following images was taken last year.

The tours for available in cherry blossoms period in Hirosaki

The world’s longest cherry-lined road sightseeing day tour

Cherry Blossoms Ashino Park & Tsuru-no-maihashi Bridge sightseeing tour