RAINSTORM IN SOUTHERN FLORIDA, JANUARY 21, 1957

Abstract

The storm situation of January 21, 1957, is studied and the vorticity and horizontal divergence patterns are computed from analyzed synoptic maps at low and high elevations of the troposphere. Contour and streamline charts for the period are presented to show that consideration of many of the synoptic parameters ordinarily used in analysis and forecasting would not lead one to expect such heavy rainfall. Computations of divergence are compared with the rainfall charts in an effort to determine the cause of the heavy rainfall which varied in amount up to 21½ inches within a 24-hour period. The divergence patterns move horizontally with time in such a manner that a high-level divergence area becomes superimposed over a low-level convergence area at the time of heavy rain.