1. The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 30 December 2013 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 precipitation deficits continue over the core monsoon region and southern Brazil. During the last 7 days (23-29 Dec 2013), below-average precipitation was observed over southern Brazil, Paraguay, Uruguay and northern Argentina. Above-average precipitation was observed over Suriname, French Guiana, and portions of eastern Brazil. For 30 December 2013 - 5 January 2014, below-average precipitation is predicted for most of the Amazon Basin, central Brazil, and eastern Bolivia. Above-average precipitation is predicted for Peru, southern Paraguay and southern Brazil. Highlights

4. Rainfall Total & Anomaly Patterns: Last 7 Days During the last 7 days, below-average precipitation was observed over southern Brazil, Paraguay, Uruguay and northern Argentina. Above-average precipitation was observed over Suriname, French Guiana, and portions of eastern Brazil. TotalAnomaly

5. Rainfall Totals & Anomaly Patterns: Last 30 Days During the last 30 days, below-average precipitation was observed over southern Venezuela, southeastern Colombia, portions of the Amazon Basin, southern Brazil, northeastern Argentina and Uruguay. Above-average precipitation was found over western Colombia. Bolivia, and most of Northeast Brazil. TotalAnomaly

6. BP Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau 90-day rainfall totals are below average over the southern Amazon Basin, the western Brazilian Plateau, and southern Brazil. Recent heavy rains have helped to alleviate long term deficits over the Brazilian Plateau.

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 above average in the western equatorial Pacific and near average in most of the equatorial Pacific between 180W and the South American coast. SSTs are slightly below average in the central equatorial 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 21-27 December 2013, anomalous cyclonic circulation (red C) was observed over central South America, indicating a weaker-than-average Bolivian High. Lower panels: Anomalous rising motion was found over eastern Brazil, and the southern Amazon Basin, and anomalous sinking motion was observed over southern Brazil and northern Argentina, consistent with the pattern of anomalous rainfall shown in slide 4. 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. C

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 21-27 December 2013, temperatures were above average in southern Brazil, Uruguay, northern and eastern Argentina, and central Chile.

10. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 30 Dec 2013– Days 1-7 Anomaly Note: Note: Bias correction based on last 30-day forecast error.

11. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 30 Dec 2013– Days 8-14 Anomaly Note: Note: Bias correction based on last 30-day forecast error.

12. For Days 1-7 (30 Dec 2013-5 Jan 2014), below-average precipitation is predicted for most of the Amazon Basin, central Brazil, and eastern Bolivia. Above-average precipitation is predicted for Peru, southern Paraguay and southern Brazil. For Days 8-14 (6-12 Jan 2014), below-average precipitation is predicted for the northern and eastern Amazon Basin, and central Brazil. Above-average precipitation is predicted for Peru, northern Bolivia and Paraguay. NCEP/GFS MODEL FORECASTS

13. Forecast Verification Forecast from 16 Dec 2013 Valid for 23-29 Dec 2013 Forecast from 23 Dec 2013 Valid for 23-29 Dec 2013 Observed 23-29 Dec 2013

14. Climatology Rainy Season Dates ONSETDEMISE

15. Precipitation Climatology

16. Precipitation Climatology Animation