1. The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 4 June 2012 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. During the last 7 days, above-average precipitation was mainly observed over eastern Colombia, and below-average rainfall was found over the other places to the north of 7S and Uruguay. For 4-10 June 2012, below-average precipitation is predicted for Peru, extreme southern Brazil, and most of the regions to the north of 5S except the above-average precipitation over central Colombia. Above- average precipitation is also predicted for southwestern and southern Brazil. For 11-17 June 2012, below-average precipitation is predicted for most of northern and northwestern South America and extreme southern Brazil, and above-average precipitation is predicted for central Colombia and portions of eastern Argentina. Highlights

4. Rainfall Total & Anomaly Patterns: Last 7 Days During the last 7 days, above-average precipitation was mainly observed over eastern Colombia, and below-average rainfall was found over the other places to the north of 7S and Uruguay. TotalAnomaly

5. Rainfall Totals & Anomaly Patterns: Last 30 Days During the last 30 days, above-average precipitation was mainly observed over central Colombia and portions of northwestern Brazil, eastern Bolivia, and eastern Argentina. Below-average rainfall occurred over most regions to the north of 10ºS, extreme southern Brazil, and Uruguay. TotalAnomaly

6. BP Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau 90-day rainfall totals are clearly below average over the southern Amazon basin, the Brazilian Plateau (core monsoon region), and southern Brazil.

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 Above-average SSTs are observed in much of the equatorial Pacific Ocean. (For more details concerning El Niño – La Niña, go to the link below.)

8. Atmospheric Circulation Recent 7 days Upper panels: During the period of 27 May – 2 June 2012, in the upper troposphere, an anomalous anticyclonone (red A) was observed over west coastal regions of subtropical South America and an anomalous cyclone (red C) was seen over western Brazil. Lower panels: Anomalous sinking motion (positive omega) was observed over western Argentina, and anomalous rising motion (negative omega) occurred over northwestern South America and southern- 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. C A

9. 925-hPa Wind &Temperature Recent 30 DaysRecent 7 Days Low-level (~600 m) 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 of 27 May – 2 June 2012, temperatures were above average over much of the central and eastern South America.

10. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 4 June 2012 – 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 4 June 2012 – Days 8-14 Anomaly Note: Note: Bias correction based on last 30-day forecast error.

12. For Days 1-7 (4-10 June 2012), below-average precipitation is predicted for Peru, extreme southern Brazil, and most of the regions to the north of 5S except the above-average precipitation over central Colombia. Above-average precipitation is also predicted for southwestern and southern Brazil. For Days 8-14 (11-17 June 2012), below-average precipitation is predicted for most of northern and northwestern South America and extreme southern Brazil, and above-average precipitation is predicted for central Colombia and portions of eastern Argentina. NCEP/GFS MODEL FORECASTS

13. Forecast Verification Forecast from 21 May 2012 Valid 28 May – 3 Jun 2012 Forecast from 26 May 2012 Valid 26 May – 1 Jun 2012 Observed 28 May – 3 Jun 2012

14. Climatology Rainy Season Dates ONSETDEMISE

15. Precipitation Climatology

16. Precipitation Climatology Animation