AOSC Departmental Seminar
October 22, 2015

Synoptic and mesoscale interactions during heavy rainfall events in the Caribbean

Arlene Laing


 Heavy precipitation events that caused fatalities and extensive damage in the eastern Caribbean islands are analyzed to assess the mesoscale and synoptic influences on their initiation and evolution. While hurricanes in the Caribbean garner much international attention, they are a relatively rare occurrence in any given island. Much more frequent are other heavy rainfall and severe weather events that endanger lives, infrastructure, and the economies of the islands. Forecasting convective precipitation, including tropical cyclone-related precipitation, is a challenge, especially in mountainous islands where rainfall can be intense and localized. 

This study uses radar, satellite, surface networks, and model analyses to determine how mesoscale and orographic precipitation evolve and the processes that interact on multiple scales to produce areas of extreme rainfall. The cases are from 16-19 April 2013, which caused 330mm of rain in two days and two deaths from landslides in Dominica; 24-25 December 2013, which caused torrential rain (> 400 mm in 24 h at one station), severe thunderstorms, 18 deaths, and widespread destruction in St. Vincent and the Grenadines, St. Lucia, and Dominica; 28-31 October 2010, intense rain and high winds associated with the rapid intensification of Hurricane Tomas, which left 12 people dead in St. Lucia. These case studies help improve our conceptualization of intense mesoscale convective precipitation in the tropics.