Southern Brazil Braces for Excessive Rainfall Through Midweek
Southern Brazil is facing potential heavy to excessive rainfall through the first half of next week, with some areas expected to see accumulations between 150 mm and 200 mm, according to MetSul Meteorologia. A low-pressure system and an upcoming extratropical cyclone are projected to cause persistent instability across Rio Grande do Sul, Santa Catarina, and Paraná.
Why is so much rain expected?
The instability is a result of a low-pressure center currently acting over Southern Brazil, according to MetSul Meteorologia. This system is expected to develop into an extratropical cyclone located offshore in the Atlantic.
A cold front derived from this cyclone will bring additional rain to the region. This front may then become semi-stationary due to atmospheric blocking, a process that could maintain instability and increase overall rainfall volumes.
What is the forecast for Sunday, May 28?
Rain is expected to affect the entirety of Rio Grande do Sul on Sunday. MetSul Meteorologia warns of moderate to strong intensity in various locations, with a particular risk for the northern half of the state. Isolated storms involving wind, lightning, and occasional hail are also possible.
The North and Northwest of Rio Grande do Sul are identified as the highest-risk areas. In these locations, 24-hour accumulations could reach between 50 mm and 100 mm, which may lead to flooding or localized flash floods, according to the report.
In Santa Catarina, rain is expected in most regions, except for some areas in the Northeast. In Paraná, instability is projected to decrease in the early afternoon before increasing again from the afternoon into the evening, specifically affecting the West, Center, and South of the state.
What happens after the rain?
Unstable weather is expected to persist across Southern Brazil from Monday, May 29, through Thursday, June 2. Numerical models, including the Canadian (CMC), German (Icon), and European (ECMWF) models, all indicate that high volumes will continue through the first half of the week.
A polar air mass is expected to arrive during the second half of the week, which should stabilize the weather for most of the region, according to the forecast.
Frequently Asked Questions
What are the projected rainfall totals for the region?
Some areas may see accumulations between 150 mm and 200 mm, with even higher totals possible in certain locations.
Which areas are at the highest risk for flooding?
The highest risks include the North and Northwest of Rio Grande do Sul, parts of Santa Catarina, and the South and Southwest of Paraná.
When will the unstable weather pattern end?
Unstable weather is expected to last until Thursday, June 2, before a polar air mass arrives to stabilize the region.
How are local authorities in your area preparing for these projected rainfall totals?
