、。
It'll probably snow tomorrow.
Literal
Tomorrow, snow [subject-が] fall probably.
Simple weather prediction. 雪が降る = 'snow falls' — Japanese uses the intransitive 降る ('to fall') for precipitation, with the weather phenomenon as the subject marked by が. Standard for rain (雨が降る), snow (雪が降る), and hail (ひょうが降る).