Deep Layer Soil Moisture Anomalies Drying…Central Brazil Drought Strengthening

Fig. 1: November 15-21, 2023, deep layer (10-200 CM) soil moisture anomalies.  

Discussion: Deep layer soil moisture anomalies are trending drier in Central/Southwest Brazil as drought potential in this region increases (Fig. 1). The already established deep layer soil moisture dryness in North Brazil persists. The soil moisture dry trend is propelled by anomalous heat so far in November across Brazil (Fig. 2). A drier than normal rainfall pattern continues over Northern Brazil and has increased near and east of Bolivia eastward to the Brazil East Coast (Fig. 3). Wet weather has persisted across West and Southeast Brazil.

Fig. 2-3: November 2023 (so far) South America temperature and rainfall anomalies.  

Fig. 4-7: Brazil 15-day percent of normal forecast by the GFS and the 16-20-day ECM rainfall anomaly outlook.

The GFS percent of normal rainfall forecast across South America yield dryness into early next week across Eastern Brazil with wet focus across the Southern Brazil and Paraguay (Fig. 4).  In the 6-10-day period Central Brazil is the dry zone while Northern Argentina trends wetter and East/Southeast observes scattered thunderstorms (Fig. 5). In the 11-15-day period, the outlook expands wet weather risk heaviest east of Paraguay and Northeast Brazil (Fig. 6). In the 16-20-day outlook by ECM indicates a widespread thundershower risk in Brazil (Fig. 7).