This is a screenshot from the Japan Meteorological Agency’s website. It shows “storm warnings” for all of Kumamoto. The Japanese side of the site presents these as 暴風警報 (bofu keiho; strong wind warnings). Kumamoto University cancels classes when such warnings are issued for Kumamoto City. However, if warnings are rescinded, Kumadai may hold classes later in the day. The details are explained in the following pdf:
http://www.kumamoto-u.ac.jp/daigakuseikatsu/kyoumu/kisyoyoho/kisyoyoho.pdf
Unfortunately, Kumadai doesn’t provide any information on any of its home pages (regardless of the language) about today’s classes.