It is safe, but you are probably jumping the gun in your region. Grass does not need fertilizer until it starts growing. Fertilizing earlier just encourages spring weeds to get growing quickly before the grass wakes up.

Safe yes, but like Bill said, too early. Wait until the forsythia start blooming, then fertilize. At that point, the grass will have broken dormancy and started to grow.

It's still a big shot of nitrogen awfully early, but at least it won't be wasted...