The 2020 Atlantic hurricane season is off to a busy start. By the first week of June, Tropical Storm Arthur had already brushed North Carolina, Tropical Storm Bertha had drenched South Carolina, and the third named storm of the year— Cristobal—was dropping torrential rain on the Yucatán Peninsula.
The storm first developed in the Pacific in late May as Tropical Storm Amanda, spinning off the southern end of a seasonal low-pressure pattern called the Central American Gyre. After making landfall in Guatemala and causing deadly floods in El Salvador, Amanda weakened and became less organized as it crossed Central America. It then reorganized and began to intensify as it reached the Atlantic Ocean and encountered the north end of the gyre. While lingering over the Yucatán Peninsula for several days, the storm dropped tremendous amounts of rain on parts of Mexico, Belize, and Guatemala.
The map above shows rainfall accumulation in Central America from May 27 to June 5, 2020. Rainfall totals were particularly intense in the Mexican states of Yucatán, Campeche, and Quintana Roo. These data are remotely-sensed estimates that come from the Integrated Multi-Satellite Retrievals for GPM (IMERG), a product of the Global Precipitation Measurement (GPM) mission. Local rainfall amounts can be significantly higher when measured from the ground.
According to the U.S. National Hurricane Center, the storm dropped as much as 65 centimeters (25 inches) of rain on parts of Mexico; some locations in Guatemala and El Salvador saw 90 centimeters (35 inches). Deadly flooding swamped hundreds of homes in El Salvador, prompting that country’s president to declare a state of emergency.
National Hurricane Center forecast models show the storm moving northward over the Gulf of Mexico toward Louisiana and other Gulf Coast states from June 6-8.
NASA Earth Observatory image by Joshua Stevens, using IMERG data from the Global Precipitation Mission (GPM) at NASA/GSFC. Story by Adam Voiland.