The South American Monsoon System Recent Evolution and

The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 13 November 2012 For more information, visit: http: //www. cpc. ncep. noaa. gov/products/Global_Monsoons/American_Monsoons

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

Highlights • During the last 7 days, below-average precipitation was observed over most regions north of 10 S, eastern Peru, and extreme southern Brazil. Above-average rainfall was mainly found over southeastern Brazil. • For 13 -19 November, above-average precipitation is predicted for Colombia, Ecuador, and latitudinal band 10 S-20 S, and belowaverage precipitation is predicted over northeastern South America, Paraguay, Uruguay, extreme southern Brazil, and northeastern Argentina. • For 20 -26 November, above-average precipitation is predicted over Colombia, southeastern Brazil, Bolivia, and eastern Argentina, and below-average precipitation is predicted over northeastern South America, Peru, and western and extreme southern Brazil.

Rainfall Total & Anomaly Patterns: Last 7 Days Total Anomaly During the last 7 days, below-average precipitation was observed over most regions north of 10 S, eastern Peru, and extreme southern Brazil. Above-average rainfall was mainly found over southeastern Brazil.

Rainfall Totals & Anomaly Patterns: Last 30 Days Total Anomaly During the last 30 days, below-average precipitation was observed over most regions north of 30 S. Above-average precipitation was mainly found over portions of central Columbia and eastern Argentina.

Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau BP • 90 -day rainfall totals are clearly below average over the southern Amazon basin, Brazilian Plateau, and southern Brazil.

Tropical Pacific and Atlantic SST Anomalies Above-average SSTs are observed in the equatorial Pacific and Atlantic Oceans. Above-average SSTs are found in 10 -20 N and below-average SSTs are observed in 1020 S in the Atlantic Ocean. (For more details concerning El Niño – La Niña, go to the link below. ) A weekly Power. Point summarizing the ENSO Cycle: Recent Evolution, Current Status and Predictions is available at: http: //www. cpc. noaa. gov/products/precip/CWlink/MJO/enso. shtml

Atmospheric Circulation Recent 7 days • Upper panels: During the period of 4 -10 November, anomalous upper-tropospheric anticyclonic flow was observed over central Argentina and eastern Brazil. A • Lower panels: Anomalous rising motion (negative omega) was observed over 10 S-25 S and central Argentina, while sinking motion was found over northeastern South America. Rising motion (negative omega, yellow/red shading), usually associated with wetter- thannormal conditions. Sinking motion (positive omega, blue shading), usually associated with drier-than-normal conditions.

925 -h. Pa Wind &Temperature Recent 30 Days Recent 7 Days • During the 7 -day period of 4 -10 November 2012, temperatures were above average over northwestern and extreme southern Brazil, southern Paraguay, Uruguay, and northeastern Argentina. 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 -h. Pa are usually similar to surface observations. Note: Areas with surface pressure below 925 -h. Pa are masked out.

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 13 Nov 2012 – Days 1 -7 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 13 Nov 2012 – Days 8 -14 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS MODEL FORECASTS • For Days 1 -7 (13 -19 November), above-average precipitation is predicted for Colombia, Ecuador, and latitudinal band 10 S-20 S, and below-average precipitation is predicted over northeastern South America, Paraguay, Uruguay, extreme southern Brazil, and northeastern Argentina. • For Days 8 -14 (20 -26 November), above-average precipitation is predicted over Colombia, southeastern Brazil, Bolivia, and eastern Argentina, and below-average precipitation is predicted over northeastern South America, Peru, and western and extreme southern Brazil.

Forecast Verification Forecast from 29 Oct 2012 Valid 5 -11 Nov 2012 Unavailable Forecast from 5 Nov 2012 Valid 5 -11 Nov 2012 Observed 6 -12 Nov 2012

Climatology Rainy Season Dates ONSET DEMISE

Precipitation Climatology

Precipitation Climatology Animation