no vaya a ser que

Conjunction

followed by a subjunctive clause

(仮定法節が続く) in case / (仮定法節が続く) lest

English Meaning

(followed by a subjunctive clause) in case / (followed by a subjunctive clause) lest

Lleva un paraguas, no vaya a ser que llueva durante el viaje.

旅行中に雨が降るかもしれないので、傘を持って行ってください。

Bring an umbrella in case it rains during the trip.