A stalled frontal boundary with several areas of low pressure tracking along it will bring the threat for thunderstorms and heavy rainfall to areas from northeast Argentina through Uruguay.
Scattered showers and thunderstorms will impact areas from Santa Fe and Rosario to Buenos Aires and Montevideo through Saturday as the front settles over the region.
By Sunday, another front will approach from the south, enhancing rainfall across the entire region. Locally heavy rainfall is expected Sunday through Monday in Rosario, Buenos Aires and Montevideo.
Rainfall amounts of 50-100 mm (2-4 inches) are expected, along with gusty thunderstorms.
On Tuesday and Wednesday, the front will stall across central Uruguay to bring extremely heavy rainfall to the northern two-thirds of Uruguay and extreme northeast Argentina.
Rainfall will average 100-200 mm (4-8 inches) from near and north of Santa Fe, Argentina eastward through into central and northern Uruguay. Local rainfall amounts of 300 mm (12 inches) or greater are possible.
Other cities in the path of the heaviest rainfall include Gualeguaychu and Salta in Argentina and Durazno in Uruguay.
A stretch of more tranquil weather is expected for the second half of next week as the frontal boundary presses northward into southeast Brazil.