1. The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 4 January 2010 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. An stationary front during the last week brought heavy rainfall and flooding over portions of southeastern Brazil. More than 60 death has been reported in the state of Rio de Janeiro due to Mudslides. Highlights

4. Rainfall Total & Anomaly Patterns: Last 7 Days During the last 7 days above-average rainfall was observed over most of Brazil with the exception of below-average rainfall over the western Amazon basin and portions of southern Brazil. Heavy rainfall, flooding and mudslides were observed over the state of Rio de Janeiro. TotalAnomaly Rio de Janeiro

5. Rainfall Totals & Anomaly Patterns: Last 30 Days During the last 30 days above-average rainfall was observed in many areas from northeastern Argentina northward into Brazil. Below average rainfall was observed over the northwestern Amazon basin extending southeastward to the northeastern Brazil coast (near Bahia). TotalAnomaly

6. BP Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau 90-day rainfall totals are near-average over the southern Amazon basin (SA) and central Brazil (CB), and below-average over the north- central Amazon basin (NCA) (deficits of about 120 mm) 90-day rainfall totals in southern Brazil are about 170 mm above-average. SB CBNCA SA

7. Tropical Pacific and Atlantic SST Anomalies During the last week, equatorial SSTs were at least 1°C above-average across most of the equatorial Pacific Ocean, and greater than 2°C above average in portions of the central and eastern Pacific. SSTs were slightly above-average in the equatorial Atlantic. 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

8. Atmospheric Circulation Recent 7 days 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. During 27 Dec 09 – 2 Jan 2010, anomalous 200-hPa anticyclonic circulation dominated southeastern South America with the center of circulation located near the coast of Rio de Janeiro in Brazil. Anomalous rising motion (negative omega) and above-average rainfall (see slide 4) were observed over most of Brazil (red rectangle in bottom right panel) on the west flank of the anomalous anticyclonic circulation center. 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 (27 Dec 09 – 2 Jan 2010) above-average temperatures were observed over the eastern coast of Brazil and the adjacent Atlantic Ocean. Stronger- than-average low-level cyclonic circulation was centered near Rio de Janeiro (right panel). C

10. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 4 January 2010 – Days 1-7 Anomaly Note: Note: Bias correction based on last 30-day forecast error. NOT AVAILABLE

11. NCEP/GFS Model Forecasts Bias-Corrected Precipitation Total Forecasts from 4 January 2010 – Days 8-14 Anomaly Note: Note: Bias correction based on last 30-day forecast error.

12. For Days 1-7 --- NOT AVAILABLE. For Days 8-14 (11-17 Jan 2010), below-average rainfall is predicted over eastern Brazil (states of Minas Gerais and Bahia) and over portions of the northwestern and southern Amazon basin. Above-average rainfall is predicted over the northern Amazon basin, northern Peru and eastern Ecuador, Paraguay, portions of southern Brazil and northeastern Argentina. NCEP/GFS MODEL FORECASTS NOTE: See forecast verification in the next slide.

13. Forecast Verification Forecast from 13 Dec 2009 Valid 27 Dec – 2 Jan 2009 Forecast from 20 Dec 2009 Valid 27 Dec – 2 Jan 2009 Observed 28 Dec 09 - 3 Jan 2010

14. Climatology Rainy Season Dates ONSETDEMISE

15. Precipitation Climatology

16. Precipitation Climatology Animation