Brazil Drought Concerns; Wet Bias is Stronger with Medium-range Forecasts

Focus on Brazil Drought
12/13/2023, 12:54 pm EST
El Nino High Wind/Heavy Rain Event East U.S. SUN/MON
12/14/2023, 2:10 pm EST
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Fig. 1-2: Mega-cluster ensemble “most likely” 1-5-day temperature and precipitation anomalies across South America.

Discussion: The mega-cluster 1-5-day forecast favors a strong anomalous hot pattern centered on Paraguay to East-central Brazil (Fig. 1). The same area is projected drier than normal while the heavy rain zone is forecast across East Argentina and northwest continent (Fig. 2). In the 6-10-day forecast, marginally hot weather is forecast for Interior Southeast Brazil (Fig. 3) while Northeast Brazil becomes a heavy rain zone (Fig. 4). Central to Southeast Brazil is slightly less wet than normal. In the 11-15-day period, marginally hotter than normal weather remains across Paraguay to East Brazil (Fig. 5) while the dry bias is across East Brazil (Fig. 6). Please note that models, including ECM, are steadily showing too wet bias in medium-range rainfall forecasts across Brazil (Fig. 7-8).

Fig. 3-4: Mega-cluster ensemble “most likely” 6-10-day temperature and precipitation anomalies across South America.

Fig. 5-6: Mega-cluster ensemble “most likely” 11-15-day temperature and precipitation anomalies across South America.

Fig. 7-8: The ECM 6-10-day/11-15-day rainfall forecast bias from the past 7 days.