non-frontal depression A low-pressure system that does not develop from a frontal wave (as do typical mid-latitude frontal cyclones or depressions). Most tropical cyclones are non-frontal. Various conditions can lead to the formation of depressions without frontal characteristics. See also cold low; lee depression; polar-air depression; and thermal low.

non-frontal depression Low-pressure system that does not develop from a frontal wave as do typical mid-latitude frontal cyclones (or depressions). Most tropical cyclones are non-frontal. Various conditions can lead to the formation of depressions without frontal characteristics. See also COLD LOW; LEE DEPRESSION; POLAR DEPRESSION; and THERMAL LOW.