Dynamical Analysis of Extreme Precipitation Events in New England

The purpose of this research is to identify precipitation extremes in New England, and to investigate the nature of the events that lead to these extremes. Station-based daily precipitation is used, and local extremes are determined for each station. Extreme events are distinguished by temporal characteristics such as precipitation duration (single or multi-day events) and rainfall rate, as well as spatial scales of influence, such as single-station events or regional, multiple-station events. Various atmospheric forcing mechanisms, including tropical storms, synoptic storms, and airmass characteristics are linked to these event types, in order to better identify the dynamics that drive extreme precipitation events. Storm tracks are used to identify potential synoptic and tropical storm forcing. Emphasis is placed on identifying synoptic-scale dynamics linked to extreme precipitation. The dynamical analyses include investigation of flow fields, frontal mechanisms associated with synoptic storms and shortwaves, baroclinicity, moisture availability and atmospheric buoyancy. The time period 1979-2008 is used, in order to make use of a consistent set of precipitation and atmospheric datasets, such as the USHCN and Unified Precipitation datasets, as well as the MERRA and CFSR reanalysis datasets.