What's the Difference Between 吹风 and 刮风?
"今天吹风很大" is a wrong sentence, which should be replaced with "今天刮风很大".

According to Baidu Dictionary(the interpretations from baidu dictionary)the term "吹风" has following meaning:

1) makes gas through some instrument.

2) let wind blow

3) use blower to dry one's hair

4) let somebody know something in advance

However, the term "刮风" has absolutely different meaning from term "吹风" because it describes as a natural phenomenon, i.e. the horizontal component motion of the air. (According to Baidu Encyclopedia!)