Chile on Storm Alert: Thunderstorm Warning for the South Today as Another Atmospheric River Looms
Chile · Weather
Key Facts
—Today. Chile’s meteorological service (DMC) warns of probable thunderstorms on Sunday afternoon and evening across La Araucanía, Los Ríos and Los Lagos, including Chiloé, under aviso A507/2026.
—Last week. A category-4 atmospheric river drove a frontal system across central-southern Chile on 23–24 September; Corral in Los Ríos recorded 123 mm of rain in 18 hours, and red alerts with evacuations were declared in the south.
—Monday. Rain returns to Santiago on 28 September, with possible thunderstorms and wind gusts of up to 70 km/h, according to Meteored.
—Early October. Models show a new frontal system with another atmospheric river, possibly category 3, reaching Chile at the start of October, with a high freezing level raising flood risk in the southern mountains.
—Pattern. Above-average rainfall is likely in 14 of Chile’s 16 regions in the coming week, heaviest between Biobío and Aysén, in a year that has already produced the country’s worst July storm in three decades.
Chile is bracing for another round of severe weather: thunderstorms are forecast for the south on Sunday, rain returns to Santiago on Monday, and forecasters already see a second atmospheric river forming for the first days of October.
Thunderstorm Warning for Sunday
The Dirección Meteorológica de Chile (DMC) issued aviso A507/2026 on Saturday evening, warning of probable thunderstorms from Sunday afternoon into the night. In La Araucanía the warning covers the valley and precordillera; in Los Ríos it includes the coastal range, valley and precordillera; and in Los Lagos it extends across the valley, precordillera, Chiloé and the interior coast, La Tercera reported on Sunday.
The aviso is linked to persistent atmospheric instability after the passage of last week’s frontal system — a pattern that has barely let up across the centre and south of the country.
What the Category-4 River Did This Week
The system that crossed Chile on Wednesday and Thursday arrived with an atmospheric river rated category 4 — the second-highest level on the five-step scale. Meteored put the probability of an extreme event at over 90% between Los Ríos and La Araucanía, and at 80–90% for Biobío. Corral, on the Los Ríos coast, accumulated 123 mm of rain in just 18 hours.
The DMC maintained alerts for moderate to heavy rainfall from the Maule to Los Lagos, with winds of up to 80 km/h in the precordillera and cordillera, and warned of a high freezing level, the “isoterma cero”, which turns precipitation to rain even high in the mountains and sharply raises the risk of river flooding. A separate thunderstorm warning covered nine regions, including the Santiago cordillera, from Thursday into early Friday. Senapred said the event stretched from O’Higgins to Magallanes, and red alerts with evacuations were declared in parts of the south on Thursday, according to Prensa Latina.
Santiago’s Turn on Monday
The capital, largely spared by last week’s core rainfall, is next in line. Meteored confirms that showers return to Santiago on Monday 28 September, possibly accompanied by thunderstorms and wind gusts of up to 70 km/h. Central Chile more broadly should expect thunderstorms at the start of the week as the instability drifts north.
In the north, a warm coastal atmosphere, boosted by the coastal El Niño warming Pacific waters, will favour intense drizzle and light rain in places such as Tocopilla, Paposo, Caldera and Huasco, an unusual pattern driven by high sea temperatures and a developing coastal trough.
Another Atmospheric River at the Start of October
The European ECMWF model points to a wet week almost everywhere: above-average precipitation is likely across 14 of Chile’s 16 regions, with the heaviest falls concentrated between Biobío and Aysén. That is where the next frontal system is expected to arrive at the start of October, again reinforced by an atmospheric river, this time possibly category 3, and again with a high freezing level in the south.
The sequence fits an extraordinary year. July brought what specialists called Chile’s most intense storm system in three decades, with more than 16,000 people evacuated at its peak and a tornado that injured one person in Ñuble. September has continued the pattern: preventive alerts ran through the Fiestas Patrias weekend, and two significant frontal systems are now set to bookend the month.
What We Could Not Confirm
Senapred had not published a consolidated national damage and evacuation balance for the 23–24 September system at the time of writing, so we cannot give verified totals beyond the confirmed Corral rainfall figure and Thursday’s red-alert declarations. The strength of the early-October atmospheric river remains a projection — category 3 is the current model estimate and could change. We could also not confirm whether class suspensions will be ordered in any region on Monday.
More: Chile news in English, every day from The Rio Times.
Frequently Asked Questions
What is the DMC warning for Chile this Sunday?
Aviso A507/2026 warns of probable thunderstorms on Sunday afternoon and evening in La Araucanía, Los Ríos and Los Lagos, including Chiloé. It follows days of heavy rain driven by a category-4 atmospheric river earlier in the week.
Will it rain in Santiago on Monday?
Yes, according to Meteored. Showers return to the capital on Monday 28 September, with possible thunderstorms and wind gusts of up to 70 km/h, as the instability affecting the south moves into central Chile.
Is another atmospheric river coming to Chile?
Forecast models show a new frontal system reinforced by an atmospheric river, possibly category 3, arriving at the start of October, with the heaviest rain between Biobío and Aysén and a high freezing level that raises flood risk in the southern mountains.
Which regions of Chile are under the Sunday thunderstorm warning?
In La Araucanía the aviso covers the valley and precordillera; in Los Ríos the coastal range, valley and precordillera; and in Los Lagos the valley, precordillera, Chiloé and the interior coast.
Sources
La Tercera · Meteored Chile · El Desconcierto · Chilevisión · Prensa Latina
Connected Coverage
Chile’s extreme weather year is also hitting the economy — storms cut into the country’s copper output this winter.
Sources: La Tercera; Meteored Chile; El Desconcierto; Chilevisión; Prensa Latina.
This article was produced by The Rio Times’ automated AI newsroom. Editorial responsibility: Matthias Camenzind, Publisher and Editor-in-Chief. The Rio Times also runs Ask Rio Times, which answers from 100,000+ of our own articles, the daily Latin America Power Map, and prediction-market odds on elections and markets.. How we use AI · Report an error