Stratospheric Behavior Associated with the Southwestern Cut-off Low

Abstract

Data obtained from rocket soundings of the stratospheric circulation at White Sands Missile Range, N. Mex., and Pacific Missile Range, Point Mugu, Calif., indicate a close relationship between minima in the winter westerly zonal flow of the 45?55 km stratopause layer and the occurrence of tropospheric cut-off lows in the southwestern United States. Time sections of the zonal winds which illustrate this relationship are presented along with appropriate tabulations. A similar, but somewhat less well defined, relationship is indicated between maxima in the stratopause zonal flow and the subsequent filling and/or eastward movement of cut-off lows. Available temperature data indicate cooling in the region between 20 and 50 km preceding or concurrent with cut-off low development.