Identifying The Brazil Drought Trend

Charts of the day: What is the trend of Brazilian drought?

Discussion: Deep layer (10-200 CM) soil moisture anomalies and their trend is an excellent “quick look” assessment of whether ongoing drought and drought potential is increasing or decreasing. The South America drought concern area across Brazil as meteorological summer 2023-24 arrives is across Northern Brazil where Amazonia water levels/supply was at historic lows entering the season. A new drought zone was emerging in late November in Eastern Brazil and rapidly developing north of Paraguay in Southwest Brazil. Meanwhile Western Brazil has avoided drought with marginally wet deep layer soil moisture conditions. The trend as of the past week is diminished drought risk in Central Brazil while the drought area north of Paraguay has strengthened. The Northern Brazil drought remains intense although covering a slightly smaller area and Eastern Brazil drought has strengthened.

Week-2 Valid December 26, 2023-January 1, 2024: Wetter trend in Brazil.

Discussion: Split in the subtropical ridge allowing wetter weather in Brazil this week is likely to linger next week. Consequently, the wettest forecast model (GFS) is preferred as rains linger from this week into next in Brazil.

Week-3 Valid January 2-8, 2024: Northeast Brazil trend is wetter.

Discussion: Upper trough southeast of Brazil invites a moist trade wind flow into Northeast Brazil. The wetter weather suppresses anomalous heat risk in Brazil.

Week-4 Valid January 9-15, 2024: Argentina turns wet again.

Discussion: Wet weather regenerates across Argentina and is likely to continue in Northeast Brazil. Central Brazil is normally wet. Northwestern continent continues dry and hot.