|
Extreme heat has been affecting large parts of South America in the recent weeks, with temperatures reaching many new records for the winter months. Since August 20, 2023, extreme heat broke many temperature records in Chile, Bolivia, and Paraguay.
Though South America is no stranger to extreme heat, which can affect the transition zones between the tropical climates of Brazil and the more temperate climates of Argentina even in wintertime, the heat waves since mid-July are unprecedented for the winter season. Temperature anomalies at times reached more than 20 °C from the climatological mean.
|
30-day mean 500 hPa geopotential (left) and 500 hPa geopotential anomaly (middle), and tropopause temperature anomaly over the South America, 23.08.2023, source:
PSL NOAA
|
 |
 |
 |
The 30-day mean and anomaly of the 500 hPa geopotential over South America shows a distinct positive anomaly over Northern Argentina and Central Chile, extending into the Eastern Pacific. Concurrently, the same region shows a distinct drop in the tropopause temperature, indicating that tropopause levels are elevated in comparison to the climate mean. Both indicate that an extraordinary strong ridge was dominant over large parts of South America.
Since mid-July, many temperature records were broken, with many heat spikes in the overall above average conditions. In the past days towards the end of the 2023 winter season on the Southern Hemisphere, a distinct heat wave developed over South America in the boundary zone between the tropical climates in the North and the temperate climates in the South. Both Bolivia and Paraguay recorded their respective warmest days on record for the winter season with temperatures reaching up to 45.0 °C in Villamontes, BO and 41.9 °C in Nueva Asuncion, PY. In the high terrain of Peru and Chile in the Andes, temperatures at altitudes higher than 2000 m above sea level saw temperatures reach more than 25 °C. Temperatures at the world-famous Machu Picchu reached up to 29.8 °C on August 21, 2023, at an altitude of 2399 m above sea level.
This heat outbreak in the Southern Hemisphere winter might be related to the developing El-Niño conditions across the tropical Pacific, massively increasing water temperatures off the coast of South America.
Text: KG
August 24, 2023
|
