A wave of thunderstorms with heavy and excessive rain, hail, storms and numerous lightning strikes will initially hit Argentina and Uruguay with a low pressure system that will migrate towards Rio Grande do Sul. The state of Rio Grande do Sul is expected to face very adverse weather conditions this Tuesday and the Fourth with probable damage and strong impact on the population. | FABIAN RIBEIRO LEAL/FILE
MetSul Meteorology reinforces the warning issued on Sunday that Rio Grande do Sul will be affected by severe weather this Tuesday and Wednesday with the possibility of rain with high to excessive volumes, and also wind storms and hail with the possibility of intense storms and with gusts of higher winds. 100 kilometers per hour.
This is a complex meteorological scenario with two low pressures, one which could then give rise to a cyclone in the Atlantic, and also the entry of very hot air from the North which will act as fuel for the formation of powerful thunderstorm areas between Argentina, Uruguay and Rio Grande do Sul.
This is not an ordinary and common summer condition, in which the heat forms heavy clouds with isolated showers and thunderstorms from afternoon to evening. Instead, large-scale systems will operate in the state with a high potential for heavy to excessive precipitation and severe weather that will bring multiple risks.
Two low pressures, one that will come from Chile at the middle and upper levels of the atmosphere up to Rio Grande do Sul and another that will move from the Argentine northeast, under a flow of very hot air from a low-lying jet stream levels, will generate terrible weather conditions with excessive rainfall and thunderstorms, with a potentially high impact on essential services and the population.
The storms, intense to strong, will start in Argentina and Uruguay, where Meteorology has already issued several severe weather warnings, and are expected to move over Rio Grande do Sul, following an area of low pressure that will move from Chile from west to east higher than the state.
The sun appears this Tuesday morning over Rio Grande do Sul, causing a sharp increase in temperature in the morning, when it is already hot, but the weather begins to change in the west and on the border with Uruguay.
Powerful areas of instability advance from afternoon to evening from the country near Campanha and to the South, accompanying an area of low atmospheric pressure with intense to locally heavy rain and strong to strong thunderstorms, with the risk of hail and gusts of wind. winds near and above speeds of 100 km/h, causing possible damage.
Weather conditions worsen significantly between the end of the afternoon and the beginning of the morning on Wednesday across parts of the western, southern, central and eastern areas of the state. The south of Rio Grande do Sul and Campanha, in the regions of Pelotas, Jaguarão, Rio Grande and Bagé, are very worrying due to excess rain and the risk of very intense winds in several places between the end of Tuesday afternoon and start of Wednesday.
Next, very strong thunderstorms from the south of the state are expected to move over part of the eastern part of Rio Grande do Sul. In other regions the heat, which will be intense, may form isolated clouds full of rain and thunderstorms in the second half of the day, but in some places in the north-west and north of the state the rain should only arrive on Wednesday.
There is no consensus among the data on the timing of climate change in Porto Alegre and the metropolitan region. Some point to late Tuesday afternoon and others to only the early hours of Wednesday, but with intense heat preceding the rain, the risk of a storm with strong winds and/or heavy rain at the onset of climate change is high. Grande Porto Alegre.
A second low pressure is expected to reinforce instability across much of the state Wednesday with heavy, voluminous precipitation. In several regions it is expected to rain a lot, with abundant lightning and the risk of windstorms.
Very high volumes of rainfall are expected in several areas with the risk of extreme precipitation accumulations. A large number of cities are expected to see between 100 and 200mm by Thursday, but there may be isolated signs of between 200 and 300mm. The Central, Southern and Eastern parts of the state are expected to have the highest volumes, according to computer projections. Porto Alegre and the region are at high risk of excessive rainfall.
To some extent, the scenario is similar to that of January 2010, even with El Niño, with heavy rains in the center of Rio Grande do Sul and the bridge disaster in Agudo. Conditions will be conducive to flash flooding, flooding, river overflows, stream overflows, landslides and barrier collapses. The map below shows the projection of accumulated precipitation indicated by the high-resolution WRF model.
What the data shows is two months of rain in just two days in some cities. Months ago, due to El Niño, it was already known that an extreme event could occur in January 2024 and this could indeed be the case. Of concern is the fact that the most densely populated region of the state, Grande Porto Alegre, is in the highest risk zone.
Another risk is storms. Locally strong to severe storms could impact the state this Tuesday and through Wednesday. This Tuesday the risk is greater in the South, part of the West, the Center and part of the East. In the fourth the risk applies to all regions. Hail may fall, but wind is the biggest threat with the risk of storm damage from gusts near and above 100km/h in some places, which can cause trees, poles, roofs to fall and leave a large number of people in Rio Grande do Sul without electricity.
The greatest instability is expected to be concentrated in Rio Grande do Sul this Tuesday afternoon and evening and throughout Wednesday. The north and northeast of the state may still experience heavy rain and occasional thunderstorms early Thursday, but the state’s weather improves later in the day with sunshine. Friday sun, clouds and rain isolated from the heat. Over the weekend, with the exception of the northernmost areas of the state, clear weather should prevail with sunshine and more pleasant temperatures.
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2024-01-15 23:26:15
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