Building heat will dominate areas from central Chile into western and northern Argentina from this weekend into next week.
"Santiago will endure a prolonged period of heat as temperatures soar above 32 C (90 F) through at least the middle of next week," according to Senior Meteorologist Rob Miller.
At least six straight days of intense heat will create dangerous conditions for the elderly and anyone that has to work outdoors for extended periods during the day.
The heat will also be felt in west-central Argentina, from Neuquen northward to Mendoza and Santiago del Estero.
Temperatures will soar past 32 C (90 F) beginning on Saturday and lasting into next week, with the mercury approaching 38 C (100 F) on Sunday and Monday.
Farther east, scattered showers and thunderstorms will develop from northeastern Argentina into Uruguay, southeastern Brazil and Paraguay each day. This will limit any extreme heat; however, locations that do not see a thunderstorm will get above-normal temperatures.
The hottest days in Buenos Aires are expected to be on Monday and Tuesday, when temperatures near or exceeding 32 C (90 F) are most likely.
A cold front will lift northward across South America early next week spreading cooler air and thunderstorms into central Argentina.
This front will reach Buenos Aires on Wednesday and Thursday, bringing heavy, gusty thunderstorms followed by more seasonable temperatures.
While no rainfall is expected in central Chile, the front will bring relief from the heat by Thursday of next week.