Spring 2021 forecast for South America: Floods and drought in many regions




At end of August 2021, we are bringing Autumn 2021 and for Southern Hemisphere Spring 2021 forecasts for continents.

As the fourth continent, we should investigate Spring 2021 in South America.

Overall, re-strengthening of the La Nina pattern during the next months is expected, which should mean colder Earth and mainly with an important impact into South America.

QBO will be still in its easterly (colder) phase, maybe with the transition into the westerly phase around November 2021.

AO / NAO forecasts promise neutral, slightly NAO+ signals for September, NAO- signals for October, and NAO neutral to negative signal for November 2021.

Hurricane season 2021/2022 should be a little weaker than was forecasted, which should mean fewer ex-tropical storms and ex-hurricanes.

MJO should be in the wet phase until 10. September, but in dry phase between 10. September – 5. October 2021 and mainly the first period will be associated with a risk of tropical activity in the southern Caribbean, including Colombia, Venezuela, and the Guyana region.

We can look at the main patterns, expected in South America in Spring 2021:

  • Very warm and later hot Patagonia and large parts of Argentina and Chile with positive geopotential (air pressure) anomalies and drought. Heatwaves should surprise in this region very soon in Spring 2021.
  • A shift of season of rains from Colombia, Venezuela and Guyana region into Amazon, with strongly above anomaly rainfall in the region, including NE Brazil, regionally even with colder anomaly.
  • A shift of season of drought in Brazil from Central into southern regions, where will be very hot and dry, with severe heatwaves. Similar weather is possible in Paraguay, southern Bolivia or Uruguay.
  • Season of rains hit Ecuador and Peru too – but only continental parts, coast stays thanks to La nina cold and dry.
  • Tropical activity in northern coast of South America should surprise until 10. September, then is forecasted lower activity until 5. October. It´s a possibility that peak of the season in October will be too weaker (dry anomalies above the USA for October: https://mkweather.com/autumn-2021-forecast-for-north-america-long-indian-summer-and-weaker-hurricane-season-such-as-expected/).
  • Remnants of winter character weather in Fireland and Patagonia in Setpember 2021 with above average September in southernmost South America.
  • Drier western slopes of Andes thanks to La nina.
  • Dry Galapagos.

It appears, that northern and north-central Brazil should have big problems with floods and landslides in Spring 2021, while southern Brazil, Paraguay, southern Bolivia, and Uruguay with drought, heatwaves, wildfires, and crop failures. Chile and Argentina should be prematurely hot and dry, along the coast of Peru and Ecuador cold and dry thanks to La Nina. Colombia, Venezuela, Guyana region, and continental Ecuador and Peru stay similarly such as Amazon very stormy. Hurricane season will be weaker than was expected (but still above average).

Source: https://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2_body.html

Source: https://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbz700e3Mon.html

Source: https://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/euPrece3Mon.html

Source: https://www.climate.gov/news-features/blogs/enso/august-2021-enso-update-rockin%E2%80%99-out-neutral
Source: https://acd-ext.gsfc.nasa.gov/Data_services/met/qbo/qbo.html
Source: https://apps.ecmwf.int/webapps/opencharts/products/mofc_multi_eps_family_hovmoller?area=North%20Hemisphere&base_time=202108230000&parameter=geopotential%20500%20hPa

Source: https://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2_body.html

Source: https://www.ecmwf.int/en/forecasts/charts

Source: https://apps.ecmwf.int/webapps/opencharts/products/extended-regime-probabilities?forecast_from=latest
Source: https://apps.ecmwf.int/webapps/opencharts/products/seasonal_system5_tstorm_density_anomaly?base_time=202108010000
Source: https://www.cpc.ncep.noaa.gov/products/people/wd52qz/mjo/chi/cfs.gif
Precipitation – Caribbean Amazon basin
Precipitation – NE Brazil
Precipitation – S America Atlantic Coast

Precipiataion – S America Pacific Coast

Source: https://apps.ecmwf.int/webapps/opencharts/products/mofc_multi_mjo_family_time_longitudes_stamps?base_time=202108230000&filter=no&parameter=velocity%20potential%20200%20hPa
Aug 2021
Source: https://apps.ecmwf.int/webapps/opencharts/products/seasonal_system5_nino_annual_plumes?base_time=202108010000&nino_area=NINO3-4
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Author: marekkucera
Writer about weather since 2007. The goal of this project is to inform a wide audience about extremes of weather, atmospheric circulation, and climate change around the world. If you like our work, you can support us on Patreon or donate.