Synoptic-Scale Features Associated with Warm Season Heavy Rainfall over the Interior Southeastern United States

Abstract

Previous research has established links between heavy rainfall and a wide variety of synoptic features and parameters. In this study, 312 heavy rainfall events are identified over the southeastern United States and used to construct a synoptic climatology that relates 14 synoptic features and parameters to the occurrence and amounts of heavy rainfall. To carry this out, an automated synoptic typing scheme is employed to classify the heavy rainfall sample according to several characteristics of the synoptic regime. This classification provides five distinct synoptic patterns that can be associated with heavy rainfall over the southeastern United States. Commonly occurring synoptic features in each synoptic pattern are highlighted and discussed. Correlation analysis is then used to relate the occurrence and strength of these features to the heavy precipitation totals. Heavy rainfall in four out of the five identified synoptic patterns is most frequently associated with high levels of moisture at the 700-mb level. Ridging in the 850-mb warm air advection field is common over the heavy rain area as well. Numerous relationships are identified between the heavy rainfall amounts and the character of synoptic features; however, the nature of these relationships is found to vary strongly according to the synoptic pattern.