The Effect of Western Michigan's Coastline on Heavy Rainfall

The influence the irregular shape of western Michigan's coastline has on warm season heavy rainfall (≥2in) was examined using the Weather Research and Forecasting (WRF) Model (Version 3.6.1). Heavy rainfall days from 1996 to 2013 were identified using CPC Unified Precipitation Data (UPD). Once identified, Weather Surveillance Radar-1988 Doppler (WSR-88D) was used to separate heavy rain days into categories (e.g. QLCS-E/W, QLCS-N/S, popcorn, trailing, est). The category with the greatest number of days (training) contained 7 heavy rain days, with the heaviest rain generally occurring in a region where the coastline shape is concave. Two WRF simulations were run for each event, a CONTROL where no changes were made to the shape of the coastline and a STRCOAST simulation where the coastline is manipulated so that it is a straight line running N/S. Differences between the CONTROL and STRCOAST were examined and each simulation was analyzed to determine possible influences coastline shape had on the evolution of the event.