upper-level cyclone

upper-level cyclone

[¦əp·ər ¦lev·əl ′sī‚klōn]
(meteorology)
A cyclonic circulation existing in the upper air, and specifically, as seen on an upper-level constant-pressure chart; often restricted to describe cyclones associated with relatively little cyclonic circulation in the lower atmosphere. Also known as high-level cyclone; low aloft; upper cyclone; upper-level low; upper low.
References in periodicals archive ?
During a talk on the polar vortex, University of Minnesota viticulturist Peter Hemstad displayed the dictionary definition of the vortex as "a persistent, large-scale, upper-level cyclone near one of the Earth's poles," which last year dropped down well into the United States.