Changing Circulation and Seasonality of Precipitation in Northeastern North America

Abstract:

The hydro-climate of the eastern US is influenced by a mid-latitude storm track during cold season and a subtropical anticyclone during warm season. In order to understand the changing hydro-climate at a regional scale, we present a case study using the Northeast U.S., to evaluate recent and projected changes in the monthly mean annual cycle and its variability. This analysis explores dynamic and thermodynamic mechanisms underlying the projected changes in seasonality of precipitation. We analyze 16 models from the CMIP5 Historical and RCP8.5 archives and evaluate monthly mean changes in the context of robust expected changes in the seasonality of the large-scale circulation. It is argued that improved understanding of seasonal transitions has potential to increase confidence in regional projections.