在英文中，"爸爸下雪了"可以表达为"It's snowing and my dad is outside." 或者 "My dad is outside in the snow."

这个表达方式的来源是英语中的动词短语"to be snowing," 表示"下雪"的意思。例如：

It's snowing heavily. (正在大雪纷飞。)
Is it snowing where you are? (你所在的地方在下雪吗？)

"My dad is outside" 表示"我的爸爸在外面"的意思。例如：

My mom is inside cooking dinner and my dad is outside mowing the lawn. (我妈妈在家做晚饭，我爸爸在外面修剪草坪。)
Is your dad outside? I thought I saw him walking by the window. (你爸爸在外面吗？我以为我在窗外看到他走过。)

希望这些信息对你有帮助。