Upper Air Pattern Forecast Favors Above Normal Risk of Important Cold Reaching Brazil Mid-to-late Winter

Climate Impact Company Month 1- Outlook

South America

Issued: Thursday, June 26, 2025

Highlight: Upper air pattern forecast favors above normal risk of important cold reaching Brazil coffee areas mid-to-late winter.

Executive Summary: The Climate Impact Company constructed analog climate forecast valid for July through October is updated. The forecast is based on correlation with ongoing SSTA regimes and their forecast through Q3/2025 by ECMWF. The marine heatwaves (MHW) either side of South America are leading contributors to the winter pattern supporting upper-level high-pressure ridge areas with a compensating semi-permanent upper trough over the continent capable of generating cold air delivering the chill to Brazil. The risk of important cold to the Brazil coffee growing areas increases although a major freeze is not indicated. The precipitation outlook indicates improvement to drought conditions by mid-spring 2025 in North Brazil and East Argentina while elsewhere, drought continues.

Climate discussion: During June, the upper air pattern has featured upper-level high-pressure ridge areas off each coast with a compensating semi-permanent upper trough across East Argentina (Fig. 1). The upper air pattern has spawned a chilly start to meteorological winter across Northeast Argentina to far Southeast Brazil (Fig. 2) although the early season cold has not affected Brazil’s coffee-growing areas. From a climate perspective, the two upper-level high-pressure ridge areas are well-correlated to marine heat waves (MHW) located off each coast (Fig. 3-4). Operational forecast models favor the described pattern continuing into July therefore the cold risk to Southern Brazil coffee-growing areas is above normal.

Fig. 1-4: The 10-day 500 MB anomalies analysis across South America, JUN-25 temperature anomalies (so far) and the South Pacific/South Atlantic SSTA.

The ECMWF seasonal global SSTA forecast valid for AUG/SEP/OCT 2025 reveals the two MHW’s are maintained (Fig. 5). Consequently, and with confidence, the risk of a freeze reaching the Brazil coffee-growing areas through the remainder of meteorological winter is above normal. The sub-tropical/mid-latitude MHW pattern either side of South America is a leading climate predictor for the month 1-4 ahead climate forecast. Neutral ENSO is likely to continue into Q4/2025. Least certain is the potential warm-up of the Atlantic equatorial region by ECMWF as other models keep this region neutral.

Fig. 5: The ECMWF global SSTA forecast for AUG/SEP/OCT 2025.

July 2025: The upper air pattern is configured to deliver above normal risk of cold weather into central continent during mid-winter. The risk of a coffee freeze is above normal. However, a major cold outbreak is not indicated.

Fig. 6-7: The Climate Impact Company constructed analog temperature and precipitation anomaly forecast for July 2025.

August 2025: The upper air projection has changed from the previous forecast to east of Argentina to winter 2025 persistence (across Argentina). Maintained is an above normal risk of cold weather into the Brazil coffee areas. A major cold outbreak is not indicated.

Fig. 8-9: The Climate Impact Company constructed analog temperature and precipitation anomaly forecast for August 2025.

September 2025: As meteorological spring 2025 arrives, anomalous warmth replaces the chilly risk of winter across central and east continent. Significant wet weather is forecast for Northeast Argentina to Southeast Brazil.

Fig. 10-11: The Climate Impact Company constructed analog temperature and precipitation anomaly forecast for September 2025.

October 2025: As mid-spring arrives, wet weather is forecast across much of Brazil with a somewhat constricted region of very dry climate centered on the Argentina/Brazil border. Argentina is somewhat warmer than normal during mid-spring.

Fig. 12-13: The Climate Impact Company constructed analog temperature and precipitation anomaly forecast for October 2025.

Drought outlook for mid-spring 2025: The July to October 2025 precipitation anomaly forecast reveals patchy wet zones in East Argentina/Uruguay and North Brazil while Southeast Brazil to Paraguay is drier than normal. Drought conditions strengthen across and east of Paraguay and much of Southern Brazil with soils shifting wetter in East Argentina plus North Brazil.

Fig. 14-15: The Climate Impact Company constructed analog precipitation anomaly forecast for JUL-OCT 2025 and the daily soil moisture anomaly ranking analysis.