South America Drought Concern Continues to Evolve

Southeast Brazil to Northeast Argentina Drought Development Underway
12/15/2021, 11:15 am EST
NOAA (and CIC) Climate Outlooks Review
12/20/2021, 8:24 am EST
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Highlight: South America drought concern continues, widening Europe chill ahead and new cold forecast into China.

Fig. 1: Morning weather satellite picture identifies the prevailing pattern…Wet Brazil and Dry Argentina to Southeast Brazil.

South America discussion: The morning weather satellite picture across South America identifies the prevailing early meteorological summer pattern (Fig. 1). A persistent upper trough extending from well east of Uruguay to northeast Brazil maintains a wet pattern for much of Brazil. However, trailing the upper trough, an upper ridge brings a dry climate pattern to Argentina to far Southeast Brazil. This pattern is likely to last well into summer and cause drought from Northeast Argentina to Southeast Brazil.

The GFS ENS 15-day forecast looks similar forecasting building anomalous heat across Argentina to Paraguay (Fig. 2). Wet weather suppresses heat risk in Brazil. The precipitation forecast maintains dryness accelerating a drought concern from northeast Argentina to southeastern Brazil (Fig. 3). The 15-day forecast reflects the upper trough across eastern Brazil and compensating high-pressure over East-central portions of South America.

Fig. 2-3: GFS ENS day 1-15 temperature anomaly and percent of rainfall forecast across South America.

Europe/Western Russia discussion: An evolving cold regime is projected across Europe in the 6-10/11-15-day period (Fig. 4-5). Initially, the chill reaches U.K. although a warmer change is indicated days 11-15. Arctic air is generated by an intense upper trough over deepening snow cover in Northwest Russia. Some of that arctic air tries to extent westward almost reaching Eastern Europe/Baltic nations.

Fig. 4-5: GFS medium-range forecast across Europe/Western Russia of anomalous temperature.

China discussion: A NEW colder regime is forecast in the 6-10-day period into Northeast China (Fig. 6). The air mass is “polar” and not arctic. Most of China stays very warm to the south. However, in the 11-15-day period the GFS indicates the (polar) chill is more widespread (Fig. 7).

Fig. 6-7: The medium-range temperature anomaly forecast across East Asia.