"Fais attention ! Il y aura beaucoup de vent !"
"Pay attention. There will be a lot of wind." was rejected. Does "fais attention" imply there is something lurking that is physically threatening or dangerous, thus necessitating being careful, as opposed to being merely attentive or alert? Or is this a DL oversight? Thank you in advance.
"Fais/Faites attention" usually fits all cases.
If it sounds too dramatic or if there is no real danger, a teacher can advise students with "sois/soyez attentif(s)/attentive(s)" and you may tell someone leaving "sois/soyez prudent(e)(s)".
By the way, your translation is accepted.