Since the latter half of last week, a heat wave has overtaken much of Argentina and Uruguay with temperatures in some cities topping out near 42 C (108 F). The combination of more building heat over central Argentina and Uruguay through the first half of the upcoming week along with cooler more moist air to the south will set the stage for some explosive thunderstorms over central South America.
After a brief break from the near-record heat across coastal Argentina and Uruguay on Sunday, the flow from Monday through Wednesday of the upcoming week will turn toward the north and northwest helping to drive more scorching heat and humidity back to the coast.
Meanwhile, the first of two cold fronts will push toward cities like Cordoba, Buenos Aires and Montevideo later Monday and Tuesday setting the stage for the first round of storms.
On Monday, the strongest storms will likely fire across cities such as Mar Del Plata, Santa Rosa and San Rafael where flooding downpours, damaging winds and hail can occur.
By Monday night and Tuesday, the cold front will push into southern Uruguay and central Argentina bringing a risk for heavy thunderstorms from Montevideo westward to Buenos Aires and over to the capital of Argentina, Cordoba.
This first front will weaken and dissipate later Tuesday allowing the heat and humidity to build back in through Wednesday.
A stronger cold front will cross southern Argentina during the day Wednesday and then move into the central part of the country Wednesday night and Thursday.
Along and ahead of this front, strong to severe thunderstorms are likely to erupt with the strongest storms containing flooding downpours, damaging winds and hail. The severe thunderstorm threat includes cities like Montevideo, Buenos Aires and Cordoba.
The cold front will gradually march northward on Friday which will bring the threat of more heavy thunderstorms with flash flooding and damaging winds across central Uruguay and north-central Argentina. Behind the second front, relief from the heat and humidity is likely as a southerly push of cooler air penetrates deep into central South America.