Future Changes in the Contribution of Gulf of Mexico-Caribbean Sea Moisture Source: Impacts on Regional Precipitation Patterns

Abstract Central America (CA) and the eastern United States (US) is a region with a significant contribution from the Gulf of Mexico–Caribbean Sea (GM_CS) moisture source. In the context of climate change, sink patterns associated with this source may change implying significant changes in this region. Hence, this study determined future changes in the contributions to precipitation (PCs) associated with GM_CS. So, a dynamic downscaling methodology was considered using the regional climate model WRF-ARW and FLEXPART-WRF, forced with the CESM2 climate model. Specifically, a decrease in the GM_CS contribution in the CA region was projected for all seasons considered, showing a southward shift in the contribution pattern. Additionally, the sink pattern was projected to increase, but the area was projected to decrease, mainly by the end of the century, except in the autumn. In addition, for the southeastern US region, an increase in PCs in spring and autumn was projected for end-century, but a decrease in PCs by more than 40% in the summer months was projected. However, for the northeastern US, changes in PCs were amplified for both the mid- and end-century relative to the southeastern US region, with an increase projected for most periods, except for a slight decrease in the summer of 10%.