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Cold front advances, intensifies winds and stirs the sea on the São Paulo coast, raising risks of storms, rough seas, and coastal flooding during the end of the extended holiday, with rapid weather changes and the formation of unusual clouds associated with atmospheric instability.
The Civil Defense of the State of São Paulo issued an alert for moderate to heavy rain showers, wind gusts, and lightning on the eastern São Paulo coast this Sunday (3), the last day of the extended holiday.
Driven by the advance of a more active cold front across the ocean, the weather change increased atmospheric instability levels and heightened attention in coastal areas along the entire coastline.
Strong winds and the advance of the cold front on the São Paulo coast
On Saturday (2), gusts of up to 60 km/h were recorded in Baixada Santista, accompanied by changes in wind direction during the passage of storms along the coastal strip.
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Throughout the day, the meteorological system gradually advanced along the São Paulo coast and reached the height of Rio de Janeiro, expanding the area under direct influence of the instability.
Even with the presence of intense winds, rainfall volumes remained low until then, with no significant accumulations in the measurements released by the state agency.
In the North Coast, for example, Caraguatatuba recorded only 13 millimeters in 12 hours, a rate considered low given the instability scenario predicted for the remainder of the period.
Formation of shelf cloud draws attention
With the cold front moving across the ocean, there was a favorable condition for the formation of heavy clouds and the intensification of wind gusts at different points along the coastal strip.
Given this scenario, the Civil Defense maintained continuous monitoring of coastal cities, where the combination of factors such as rain, wind, and sea agitation requires redoubled attention.
The presence of the shelf cloud, known as a roll cloud, a formation associated with intense storms and rapid changes in weather conditions, drew the attention of residents and tourists.
This type of cloud forms when the cold air from the rain advances over the warm air ahead of the system, a process that usually intensifies stronger wind gusts.
Although it has an unusual appearance, the phenomenon is directly linked to the typical atmospheric dynamics of these storms and does not represent an isolated event outside this context.
According to the Civil Defense, the formation observed on the São Paulo coast coincided with the abrupt change in wind direction and the arrival of the unstable system in the region.
Rough sea and risk of surge in Baixada Santista
In addition to conditions on the mainland, sea behavior also became a concern, especially in Baixada Santista, where the forecast indicates a significant increase in sea agitation.
According to Unisanta’s Hydrodynamic Research Center, the passage of the cold front maintains the expectation of waves coming from the southern quadrant, potentially exceeding 3 meters in significant height.
The trend, according to the technical bulletin, is for this scenario to begin on Sunday (3) and extend until the early hours of Tuesday (5), keeping the alert status active.
Consequently, the waterfront strip of the region’s municipalities remains under attention within contingency plans aimed at rough seas and coastal flooding.
In practice, the rise in waves can impact maritime activities, affect areas near the sand, and increase the risk of flooding in more vulnerable spots.
In such situations, the guidance is to avoid staying in places like rocks, piers, and coastal structures exposed to the advancing sea.
Sea level rise and alert in Santos and region
Meanwhile, the interior of the estuary also requires monitoring, especially in cities like Santos, São Vicente, and Cubatão, where tidal behavior can bring additional impacts.
The forecast indicates a rise in sea level with a warning classification for inland areas, while the coastline remains on high alert due to the combination with higher waves.
Over the following days, the level may remain above normal, increasing the risk of disruptions in urban areas susceptible to flooding.
For this reason, the recommendation includes monitoring official warnings and avoiding unnecessary travel in areas historically affected by high tides.
Residents of vulnerable areas should maintain increased vigilance, especially in regions with a history of fallen trees, landslides, or sea encroachment during similar events.
In case of emergency, the indicated contacts are 199, for Civil Defense, and 193, for the Fire Department.
Furthermore, authorities emphasize the need for constant monitoring of municipal updates, as the intensity of the phenomena may vary between different coastal localities.
Monitoring remains active as long as the cold front continues to affect the São Paulo coast.
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