Understanding the Mechanisms Leading to Early Warning of Meteorological and Hydrological Drought in the U.S. Caribbean

In groundwater-limited settings, such as the U.S. Caribbean, societal, ecological, and agricultural water needs are largely supplied by regular rainfall. Consequently, Puerto Rico and the U.S. Virgin Islands are vulnerable to even short, rapid-onset dry spells, known as “flash droughts,” and drought early warning is immensely valuable. In the wake of the 2015 drought, for example, precipitation deficits were linked to the early arrival of an elevated hot, dry, dust-laden feature called the Saharan air layer. 

This project examined drought through a suite of hydrometeorological variables, drought indices, and drought definitions. The researchers compared drought episodes in the U.S. Caribbean to observational data, including soil moisture, to infer the ability of the drought indices to capture flash drought onset. They used meteorological reanalysis data to identify the local meteorological conditions driving flash drought and how these differ from conventional (slowly-developing) drought.

This project also investigated the Saharan air layer as a precursor to Caribbean drought. This project created a multi-product assessment of drought, including flash drought, and then evaluated climate mechanisms (with a focus on the role of the Saharan air layer) that are critical in improving drought early warning in the U.S. Caribbean. 

The outcomes of this project included critical monitoring and drought early warning improvements in the U.S. Caribbean islands. The researchers actively engaged with local stakeholders who have asked for improved drought information, and introduced local students to climate science. 

This project is part of the NIDIS/MAPP Drought Task Force IV.

For more information, please contact Meredith Muth (meredith.f.muth@noaa.gov).