South America: Water deficits will remain intense in Suriname & French Guiana

31 July 2019

The 12-month forecast through March 2020 indicates exceptional water deficits in French Guiana, Suriname, nearby regions of northern Brazil, northern Venezuela, the southern Atacama Desert in Chile, central Chile surrounding Valparaiso and Santiago, and around the Gulf of Corcovado.

Deficits of generally lesser intensity, punctuated by pockets of extreme to exceptional anomalies, are expected scattered throughout much of the northern bulk of the continent. In the southern half, deficits of varying intensity are forecast for most of Chile, and some moderate deficits across the border along rivers in southern Argentina.

Moderate to extreme surpluses are forecast for central and eastern Paraguay. Moderate surpluses are expected in nearby regions of northern Argentina, moderate to exceptional surpluses in Catamarca and La Rioja Provinces in northwestern Argentina, and moderate to severe surpluses in Córdoba and San Luis Provinces. Surpluses are also forecast for a pocket spanning the central border area of Peru and Bolivia, and northeastern Rio Grande do Sul in southern Brazil.

The 3-month maps (below) for the same 12-month period show the evolving conditions in greater detail.

The forecast through September indicates that the extent of intense deficits will diminish across the arc of the northernmost nations of the continent. Exceptional deficits will persist in French Guiana, and moderate to extreme deficits in neighboring Suriname. Deficits will downgrade and diminish in Venezuela, will retreat from eastern Colombia but emerge in the west, and will increase in Ecuador, where anomalies will be exceptional along the coast. In Brazil, intense deficits will persist in Amapá and along the Xingu and Tocantins Rivers in the north, the southern Amazon Basin, Mato Grosso, Matto Grosso do Sul, western São Paulo State, eastern Minas Gerais, and Espírito Santo. Deficits will be severe along the São Francisco River in southern Bahia. Intense deficits will emerge tracing the Andes Mountains through Peru and into Chile. Deficits of varying intensity are expected throughout much of central Peru, while deficits in southern Chile around the Gulf of Corcovado will nearly disappear. Deficits on the Gallegos River in Patagonia will intensify, becoming exceptional, and intense deficits will diminish, but persist, in Tierra del Fuego.

Surpluses will persist in central Paraguay, along the border of Peru and Bolivia, and many provinces in northern Argentina, and will be severe to exceptional in Paraguay. Surpluses will diminish along Brazil’s southeastern coast and in Uruguay, but moderate surpluses will persist in a pocket of eastern São Paulo State.

From October through December, deficits will shrink considerably. Intense deficits are forecast, however, for French Guiana and Suriname and across the border in Amapá and northern Pará, Brazil. Moderate to severe deficits are expected in Guyana, in southeastern Venezuela and in the north along the country’s central Caribbean coast. Moderate deficits will emerge in the northern Amazon Basin in Brazil and moderate deficits are also forecast for southern Colombia. Pockets of intense deficit will persist in northern Chile, and moderate deficits are forecast farther south around Santiago. Surpluses will shrink in Paraguay and northern Argentina with some pockets persisting in central Paraguay, and in La Rioja, Catamarca, and Córdoba Provinces in Argentina.

In the final quarter – January through March 2020 – normal conditions are forecast for much of Brazil and many other areas of the continent. Deficits are forecast for Suriname, French Guiana, and Chile. Surpluses are expected in pockets of Paraguay and northern Argentina.

(It should be noted that forecast skill declines with longer lead times.)

Heavy rainfall in the Brazilian state of Bahia swelled the Rio do Peixe, leading to the collapse of a dam in the towns of Pedro Alexandre and Coronel João Sá.

Heavy rains in southern Colombia caused landslides that killed two people late last month. 

Central Chile, including the capital city of Santiago, is reportedly suffering its worst drought in 60 years, cutting nationwide avocado production

Despite this year’s El Niño - the climate phenomenon that typically increases precipitation in Argentina and Uruguay - uneven precipitation in milk-producing regions has severely diminished pasture quality and cow nutrition, reducing output. Argentine milk production is 6.3 percent behind the prior year, and Uruguayan production is down 9.3 percent. 

There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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