1. The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 30 March 2015 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. Large long-term (90-day) rainfall deficits continue over central and southeastern Brazil. During the last 7 days (23-29 March 2015), below-average precipitation was observed over most of the Amazon Basin, southeastern Bolivia, eastern Argentina, and Uruguay. Above-average precipitation was observed over southern Suriname, French Guiana, extreme southern Colombia, Ecuador, and northern Peru. For 30 March-5 April 2015, below-average precipitation is indicated for most of the Amazon Basin, Northeast and southern Brazil, and eastern Argentina. Highlights

4. Rainfall Total & Anomaly Patterns: Last 7 Days During the last 7 days, below-average precipitation was observed over most of the Amazon Basin, southeastern Bolivia, eastern Argentina, and Uruguay. Above-average precipitation was observed over southern Suriname, French Guiana, extreme southern Colombia, Ecuador, and northern Peru. TotalAnomaly

5. Rainfall Totals & Anomaly Patterns: Last 30 Days During the last 30 days, below-average precipitation was observed over portions of the eastern and southern Amazon Basin, Bolivia, Paraguay, eastern Argentina, Uruguay, and southern Brazil. Above- average precipitation was observed over southern Suriname, French Guiana, and portions of the western Amazon Basin. TotalAnomaly

6. BP Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau 90-day rainfall deficits are present over the southern Amazon Basin (>300 mm) and the Brazilian Plateau (200-300 mm). 90-day rainfall is below average (~50 mm) over 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 SSTs are above average in the equatorial Pacific and near average in the 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 22-28 Mar. 2015, anomalous cyclonic flow (center indicated by red C) was located over the western Atlantic, with stronger-than-average westerlies extending from northern Chile eastward across northern Argentina and southern Brazil. Lower panels: Anomalous rising motion occurred over the central Andes Mts. and anomalous sinking motion occurred over portions of central and eastern 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

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 22-28 Mar. 2015, above-average temperatures were observed over central and southern Chile, and below-average temperatures were observed over central and northern Argentina, Uruguay and extreme southern Brazil.

10. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 30 March 2015 – 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 30 March 2015 – Days 8-14 Anomaly Note: Bias correction based on last 30-day forecast error.

12. For Days 1-7 (30 March-5 April 2015), below-average precipitation is indicated for most of the Amazon Basin, Northeast and southern Brazil, and eastern Argentina. For Days 8-14 (6-12 April 2015), below-average precipitation is predicted for the central and eastern Amazon Basin, Bolivia, southern Brazil, and portions of southeastern Brazil. Near-to or above-average precipitation is indicated for Northeast Brazil. NCEP/GFS MODEL FORECASTS

13. Forecast Verification Forecast from 16 March 2015 Valid for 23-29 Mar 2015 Forecast from 23 March 2015 Valid for 23-29 Mar. 2015 Observed 23-29 Mar. 2015

14. Climatology Rainy Season Dates ONSETDEMISE

15. Precipitation Climatology

16. Precipitation Climatology Animation