Is anyone really fully equipped to deal with that?
To be honest, Oman gets a massive cyclone every 5-10 years or so... and recently has spent an absolute fortune on road infrastructures and storm water management, at least in the north. Also Salalah in the south gets torrential monsoon rain for a good 2-3 months of the year every year anyway towards the end of summer, so the good thing is they're used to a ton of rain and this storm isn't coming on top of that normal rain. Hopefully everyone gets to high ground and rides it out. But there's always some people that take unnecessary risks and cross flowing water without any respect for how strong it is.
Yemen on the other hand, I have no idea how they will cope. I have to imagine they're pretty beaten up there right now as it is with the conflict and drama they already have going on there, getting everyone to safety and having a well managed rescue and recovery operations might be difficult.