Meteorologists in Brazil are tracking a fresh cyclone that should develop near the end of the week, threatening the country’s South and part of the Southeast with storms, intense rain and sudden temperature shifts after days of punishing heat.
Heatwave first, cyclone next
Before the storms build, southern Brazil is living through a stifling hot spell. Forecasts from Meteored indicate that, through Wednesday 28 January, much of the South and parts of the Southeast will see temperatures far above the seasonal average, with maximums approaching 40°C in some locations.
Through mid‑week, thermometers in parts of Rio Grande do Sul are expected to top 36°C every single day, even before midday.
This heat comes with strong humidity, driving that suffocating “sauna” feeling from the early hours. The most oppressive conditions are expected across Rio Grande do Sul, especially the western and interior zones, but the heat extends over Santa Catarina and Paraná as well.
When the weather pattern starts to change
The key transition is forecast between Thursday and Saturday, as the current hot, stable pattern gives way to spreading storms and, eventually, a coastal cyclone.
Tuesday 27: first storms fire up
On Tuesday 27 January, isolated thunderstorms are projected to flare up in Paraná. These will be the first pockets of stronger instability, still quite scattered, but they signal the atmosphere is starting to shift away from the drier, hot regime.
Wednesday 28: instability grows
From Wednesday onwards, the storm risk widens. Areas of instability expand across the South, with more locations seeing showers and short but intense downpours, mainly during the afternoon and evening, when daytime heating peaks.
Western Rio Grande do Sul, the Campanha region, and central‑western parts of Santa Catarina and Paraná are already under meteorological alert for severe storms.
Thursday 29: widespread storms over the South
By Thursday 29 January, storms are expected to spread over much of southern Brazil. New weather systems begin to organise along the western border of Rio Grande do Sul, near Argentina and Uruguay, where warm, humid air clashes with cooler air arriving from the south.
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The Uruguaiana region, in western Rio Grande do Sul, may see intense episodes early in the day, including strong gusts of wind, lightning and short‑lived heavy rain. From there, the area of instability is forecast to move east and north, reaching Santa Catarina and Paraná as the day progresses.
Friday 30 and Saturday 31: new cyclone forms off the coast
On Friday 30 January, the focus of heavy rain and thunderstorms shifts towards the eastern half of the southern states, closer to the Atlantic. The northeast of Rio Grande do Sul also enters the spotlight, alongside much of coastal and eastern Santa Catarina and Paraná.
Meteorologists expect a new cyclone to form off the Brazilian coast between Friday 30 and Saturday 31 January, between the South and Southeast regions.
This system should develop over the ocean, using the contrast between very warm, moist tropical air and cooler air masses pushing up from higher latitudes. The exact strength of the cyclone is still being modelled, but the configuration typically favours strong winds at sea, rough surf and bands of heavy rain sweeping over land, especially near the coast.
Which areas face the highest impact?
Current projections point to a broad swath of southern Brazil being affected in different stages: first by heat, then by storms, and finally by the influence of the new cyclone offshore.
- Rio Grande do Sul: intense heat, then storms starting in the west and Campanha; later, heavier rain over the east and northeast of the state.
- Santa Catarina: central‑western areas under alert for storms; coastal and eastern zones exposed to stronger winds and rain linked to the cyclone.
- Paraná: initial isolated storms on Tuesday; later, risk of high rainfall totals in central and northern areas.
Meteored estimates that by Saturday, much of the South will have seen between 50 and 80 mm of accumulated rainfall. In the centre and north‑east of Paraná, totals could surpass 100 mm, raising concern about localised flooding and urban drainage problems.
Why the rain is described as “irregular”
Despite the general stormy trend, forecasts emphasise that rain distribution, especially over Rio Grande do Sul, should be quite uneven. That means some cities might endure multiple rounds of heavy rain, while other nearby areas receive only light showers or stay dry for long stretches.
The same storm system can leave one town awash in 70 mm of rain and another, 50 kilometres away, almost untouched.
This pattern is typical of convective thunderstorms, which are driven by local heating and humidity. Those cells tend to be intense but short‑lived, often affecting narrow corridors rather than entire states equally.
What residents should watch for
With heat, storms and a forming cyclone in play within a single week, conditions can swing quickly. Local authorities in the South have flagged several short‑term risks tied to this setup:
| Risk | What can happen |
|---|---|
| Heat and humidity | Dehydration, heat exhaustion, increased demand on power grid and water supply. |
| Strong thunderstorms | Fallen branches, local power cuts, intense lightning and slick roads. |
| Heavy rain in short bursts | Flash flooding, blocked drains, rapid rises in small streams. |
| Coastal cyclone | High waves, dangerous sea conditions, coastal erosion and wind gusts onshore. |
Residents are being urged to follow updates from meteorological services closer to the key dates, particularly from Thursday onward, when the exact track and intensity of the cyclone should become clearer in weather models.
How a “Brazilian” cyclone works
In Brazil, the word “cyclone” often sounds dramatic, but it usually refers to mid‑latitude low‑pressure systems, not tropical hurricanes. These lows spin counter‑clockwise in the Southern Hemisphere and form where warm and cool air masses meet, often along fronts that sweep across southern South America.
When such a low forms just off the Brazilian coast, it can deepen and bring strong winds and heavy rain, yet it generally lacks the tightly wound eye and warm core structure of a tropical cyclone. Still, coastal communities, shipping routes and offshore activities can be significantly affected by rough seas and gusty conditions.
What this means for daily life and travel
For people living in or travelling through Rio Grande do Sul, Santa Catarina and Paraná during the 26 January–3 February window, the forecast points to a week of unstable conditions. Heat at the start may stress vulnerable groups, such as older adults and outdoor workers. Later in the week, shifting to cooler, wetter weather can cause disruptions in transport and events.
Road users might face sudden changes in visibility due to heavy showers, while flights in smaller regional airports could be delayed during periods of thunderstorms or strong crosswinds. Coastal tourism, a mainstay in Santa Catarina and Paraná, may also feel the impact as beaches see stronger waves and possible warnings against swimming or boating once the cyclone settles offshore.
For farmers, especially in Rio Grande do Sul’s western plains and the Campanha region, the irregular rain is a mixed picture. Areas that catch the heavier storms may benefit from much‑needed moisture after intense heat, yet fields could also suffer from waterlogging or hail in the most severe cells. In other locations, crops might still struggle with dryness despite the general talk of “a rainy week”.
Weather agencies will keep revising the forecast as new data arrives. For now, the message is clear: southern Brazil is moving from extreme heat straight into a turbulent, storm‑prone spell, crowned by the formation of a new cyclone offshore between Friday and Saturday.
