Brazil weather: heavy-rain alert for 7 state capitals

Brazil's National Institute of Meteorology (INMET) has a yellow alert for heavy rain in force on Sunday (Oct. 18), rated "Potential Danger," covering 1.345 municipalities in 15 states: Acre, Amazonas, Bahia, Ceará, Espírito Santo, Goiás, Maranhão, Mato Grosso, Minas Gerais, Pará, Pernambuco, Piauí, Rondônia, Roraima and Tocantins. The alert runs from midnight today until 11:59 p.m. on Monday (Oct. 19), Brasília time. Going by the list of municipalities, seven state capitals fall inside the affected area: Rio Branco, Manaus, Salvador, Vitória, Porto Velho, Boa Vista and Palmas.

What the heavy-rain alert says

According to INMET, the area under the alert can expect rain of 20 to 30 millimeters per hour, or up to 50 millimeters in a day, along with strong winds of 40 to 60 km/h. The institute rates the risk of power outages, falling tree branches, flooding and lightning as low. The alert remains in effect regardless, and residents are advised to follow updates from Civil Defense (Brazil's emergency management agency).

If gusts hit, INMET advises people not to shelter under trees, because of a slight risk of falling limbs and lightning, and not to park vehicles near transmission towers or billboards. It also recommends avoiding electronic devices that are plugged into an outlet. More information is available from Civil Defense (phone 199) and the fire department (193).

Coastal winds in the South, dry air in the Northeast

A second yellow alert, for coastal winds, is in force from 8:10 a.m. to 11:59 p.m. on Sunday for 86 municipalities in Paraná, Santa Catarina and Rio Grande do Sul. Florianópolis is on the list. The institute expects winds to strengthen along the coast, with sand dunes shifting onto buildings along the waterfront, and asks residents to contact Civil Defense at 199.

INMET also issued a yellow alert for low humidity, from 9 a.m. to 10 p.m., for 445 municipalities in Ceará, Rio Grande do Norte, Pernambuco, Alagoas, Paraíba and Piauí. The institute says relative humidity should range between 30% and 20%, with a low risk of wildfires or health problems. It recommends drinking plenty of fluids, avoiding physical exertion during the driest hours and staying out of the sun during the hottest part of the day.

Forecast for the capitals today

INMET's forecast shows showers in several capitals in the North and Southeast, as well as in Brasília, and in Porto Alegre and Teresina in the morning. Manaus should reach a high of 36 °C with a low of 26 °C, with showers in the morning and isolated ones in the afternoon. Porto Velho sits at 35 °C and 23 °C, and Rio Branco at 33 °C and 22 °C; both expect isolated showers that may bring thunderstorms in the afternoon. Palmas (32 °C and 22 °C) has showers and thunderstorms. Vitória should see a high of 27 °C and a low of 21 °C, with showers and thunderstorms in the morning and plenty of clouds afterward. Salvador is expected to top out at 32 °C with a low of 25 °C, and Boa Vista at 37 °C and 26 °C, both with plenty of clouds.

According to the model of the Norwegian weather service (MET Norway), the largest rainfall totals over the next 24 hours among the capitals named in this article are in Manaus (16.9 millimeters) and Vitória (14.8 millimeters), followed by Rio de Janeiro (9.7 millimeters). These are model estimates, not measurements. For Rio, INMET calls for 27 °C and 18 °C, with showers and thunderstorms in the morning and rain in the afternoon. São Paulo should see 24 °C and 13 °C, with isolated showers in the morning and rain in the afternoon.

The South is cool today. Porto Alegre has a high of 17 °C and a low of 13 °C, with showers in the morning, the lowest high among the 27 capitals. Curitiba reaches 20 °C, with a low of 9 °C, the lowest minimum of any capital, and INMET mentions a chance of frost in the morning. Florianópolis ranges from 13 °C to 22 °C. The highest maximum is Teresina's 39 °C, followed by Boa Vista at 37 °C and Manaus, Macapá and São Luís at 36 °C. Brasília should reach 32 °C, with a low of 18 °C, and isolated showers in the morning and showers in the afternoon.

Monday (Oct. 19)

For Monday, INMET's forecast calls for overcast skies, generally with drizzle, across much of the North. Manaus, Rio Branco, Porto Velho, Boa Vista and Palmas are all listed as overcast with drizzle (Palmas also has isolated afternoon rain), and highs in all five stay between 35 °C and 37 °C. Vitória should be overcast, with a high of 26 °C and a low of 22 °C, and Rio de Janeiro will see drizzle at 25 °C and 19 °C. São Paulo sits at 18 °C and 14 °C, and Curitiba at 16 °C and 8 °C. In Brasília, skies should be clear in the morning and overcast in the afternoon, between 18 °C and 29 °C, and Porto Alegre ranges from 9 °C to 18 °C. Teresina stays hot, with a high of 38 °C.

City forecasts describe the weather in general terms. Where a forecast and an alert differ, follow the alert, which points to the possibility of heavy rain and gusts in part of the municipality.

The temperatures cited are INMET forecasts, not measurements. The alerts and forecasts were checked on the morning of Oct. 18 (Brasília time), and the areas under alert may change during the day. The updated list is on the institute's official panel.

Sources

• INMET: weather alerts panel
• INMET: city-by-city weather forecast
• MET Norway: forecast data (CC BY 4.0 license)
• RaisLife: weather and forecast for the 27 capitals

Text by Rai, RaisLife's virtual reporter (artificial intelligence), with automated editorial review. Data: RaisLife weather panel.