1. The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 19 December2016 For more information, visit: http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/American_Monsoons http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/American_Monsoons

2. Outline Highlights Recent Evolution and Current Conditions NCEP/GFS Model Forecasts Climatology

3. Long-term rainfall deficits are present over the Amazon Basin, central Brazil and the extreme southern Brazil. During the last 7 days (12 -18 Dec 2016), below-average precipitation was observed over central Colombia, much of central and southern Brazil, Bolivia, Paraguay and northern Argentina. Above-average precipitation was observed over northern Peru, northern and eastern Brazil. For 19-25 Dec 2016, below-average precipitation is predicted over much of Bolivia, northern Argentina, central and southeastern Brazil, as well as western Venezuela. Above-average precipitation is predicted for portions of Colombia, Peru, northern Brazil, Uruguay and southern Chile. Highlights

4. Rainfall Total & Anomaly Patterns: Last 7 Days During the last 7 days, below-average precipitation was observed over central Colombia, much of central and southern Brazil, Bolivia, Paraguay and northern Argentina. Above-average precipitation was observed over northern Peru, northern and eastern Brazil. TotalAnomaly

5. Rainfall Totals & Anomaly Patterns: Last 30 Days During the last 30 days, below-average precipitation was observed over much of South America. Above-average precipitation was observed over north and central Colombia, central Paraguay and small portions of northern and eastern Brazil. TotalAnomaly

6. BP Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau 90-day rainfall deficits are present over Amazon Basin (~ 100 mm), the Brazilian Plateau (~ 80 mm) and the extreme southern Brazil (~ 90 mm).

7. Tropical Pacific and Atlantic SST Anomalies A weekly PowerPoint summarizing the ENSO Cycle: Recent Evolution, Current Status and Predictions is available at: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/enso.shtml SSTs are below average across central and eastern tropical Pacific, and above average in the tropical Atlantic. (For details concerning El Niño – La Niña, go to the link below.)

8. Atmospheric Circulation Recent 7 days Upper panels: During the period of 11-17 Dec 2016, anomalous anticyclonic flow (center noted by red A) was observed off the southeast coast of Brazil. Lower panels: Anomalous sinking motion was observed over southern South America. Anomalous rising motion was observed across Colombia and southeastern Brazil. Rising motion (negative omega, yellow/red shading), usually associated with wetter- than- normal conditions. Sinking motion (positive omega, blue shading), usually associated with drier-than-normal conditions. A

9. 925-hPa Wind &Temperature Recent 30 DaysRecent 7 Days Low-level (~600 m above sea level) wind and temperature anomalies based on the NCEP Climate Data Assimilation Systems (CDAS) analysis. The patterns of anomalous temperature and wind at 925-hPa are usually similar to surface observations. Note: Areas with surface pressure below 925-hPa are masked out. During the 7-day period 11-17 Dec 2016, below-average temperatures were observed over Paraguay.

10. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 19 Dec 2016 – Days 1-7 Anomaly Note: Bias correction based on last 30-day forecast error.

11. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 19 Dec 2016 – Days 8-14 Anomaly Note: Bias correction based on last 30-day forecast error.

12. For Days 1-7 (19-25 Dec 2016), below-average precipitation is predicted over much of Bolivia, northern Argentina, central and southeastern Brazil, as well as western Venezuela. Above-average precipitation is predicted for portions of Colombia, Peru, northern Brazil, Uruguay and southern Chile. For Days 8-14 (19-25 Dec 2016), below-average precipitation is predicted over much of northern part of South America as well as central and southern Brazil. Above-average precipitation is predicted over central Colombia, northwestern and southeastern Peru, the extreme southern Brazil and Uruguay. NCEP/GFS MODEL FORECASTS

13. Forecast Verification Forecast from 05 Dec 2016 Valid for 12-18 Dec 2016 Forecast from 12 Dec 2016 Valid for 12-18 Dec 2016 Observed 12-18 Dec 2016

14. Climatology Rainy Season Dates ONSETDEMISE

15. Precipitation Climatology

16. Precipitation Climatology Animation