(meteorology) rapid inward circulation of air masses about a low-pressure center; circling counterclockwise in the northern hemisphere and clockwise in the southern
suddenly and unexpectedly; "rain caught them unawares"; "sorrow comes to all, and to the young it comes with bittered agony because it takes them unawares"- A.Lincoln
without forethought or plan; inadvertently; "came upon the diamond unawares"