AccuWeather’s South America summer forecast for the 2018-2019 season
Drought concerns will build from Colombia through northern Brazil this summer, while rain and thunderstorms limit the heat from Peru to Uruguay.
AccuWeather meteorologist are also anticipating El Niño conditions to develop, influencing the weather pattern across South America during the summer months.
El Niño is part of a routine cycle of water temperatures in the tropical Pacific Ocean that can affect the weather around the globe.
Rain, thunderstorms to bring flood threat from Peru to Uruguay
The warm waters in the Pacific Ocean associated with El Niño will help to fuel frequent rounds of rain and thunderstorms across a section of South America this summer, stretching from Ecuador and Peru into Uruguay.
“Near to above-normal rainfall across far southern Brazil, Uruguay, Paraguay and northern Argentina will result in overall favorable conditions for crops,” AccuWeather Lead Global Meteorologist Jason Nicholls said.
Rain will also push farther north on occasion, reaching into far southern Colombia and across central Brazil, but rainfall in this zone will not be as frequent as areas to the south.
“Major cities such as Buenos Aires, Argentina, and Montevideo, Uruguay, will also have near to above-normal rainfall with temperatures near to slightly above normal,“ Nicholls added.
While these cities will experience spells of warmer weather, the wet weather pattern will limit the potential for extended heat waves.
Heavy rain may also lead to bouts of flooding across this region, according to Nicholls.
A group of people, stranded in flood waters, hold onto a rope as they walk to safety in Lima, Peru, Friday, March 17, 2017. Intense rains and mudslides over the past three days have wrought havoc around the Andean nation and caught residents in Lima, a desert city of 10 million where it almost never rains, by surprise. (AP Photo/Martin Mejia)
Persistent rain or drenching downpours from thunderstorms over the more mountainous terrain, such as in the Andes, could also bring the risk of landslides and debris flows.
Locations along the Huallaga River in Peru will be one of the areas susceptible to flooding this summer following heavy autumn rains.
As of Oct. 29, the river was more than three meters above its normal level, according to a report from the Government of Peru.
Additional rounds of heavy rain in the coming months could quickly bring a renewed risk of flooding along the river.
Drought concerns to build over eastern, northern Brazil
While a wet summer is forecast for central-west and far southern Brazil, other parts of the country will be facing dry spells and potential drought.
“Some rain is possible from the Brazilian states of Maranhao to Rio Grande Do Norte, Pernambuco, Alagoas and Sergipe early in the season, but as high pressure over the Atlantic Ocean flexes west later in the season, rains will become less frequent,” Nicholls said.
“Pockets of drought can develop in these areas as the season progresses,” Nicholls added.
This includes the cities of Rio de Janeiro, Brasília and Salvador, Brazil.
A drier-than-normal summer is also on tap across much of northern Brazil and bordering countries.
“Rainfall will be lacking from Colombia to French Guiana and north-central Brazil, resulting in developing or worsening drought conditions,” Nicholls said.
The upcoming dry pattern could cause levels in water reservoirs to drop in countries that rely heavily on hydropower for electricity, such as Colombia and Venezuela.
Heat to focus on central Chile, Argentina following early-season storms
A warm and dry weather pattern will dominate much of Chile and part of Argentina this summer with the hottest conditions holding off until the second half of the season.
“Much of northern and central Chile into central Argentina will be warmer and drier than normal with occasional rounds of heat across central Chile,” Nicholls said.
It may take until the start of 2019 before heat waves sizzle the region due to the passage of early-season storms.
“Storms will continue to push across far southern Chile and southern Argentina during December with several rounds of precipitation,” Nicholls said.
“Rainfall with any systems that reach into central Chile will be limited across the coastal and valley areas, including Santiago, but there can be early-season rain and snow over the central Andes,“ Nicholls added.
These storms will help to limit the heat across the region in December, but as the season progresses, the storms are expected to track father south, opening the door for longer stretches of hot and dry conditions.
“Heat waves will grip these areas, especially during January and February,“ Nicholls said.
The frequency of storms will also decrease across southern Chile and southern Argentina as the summer transpires, allowing for periods of tranquil, dry weather.
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