The South American Monsoon System Recent Evolution and

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The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate

The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 3 October 2011 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 •

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

Highlights • During the last 7 days, below-average rainfall was observed over much of

Highlights • During the last 7 days, below-average rainfall was observed over much of South America (north of 30 S) except for spotty aboveaverage rainfall over portions of central Colombia, northern Peru, northwestern Brazil, Bolivia, and Uruguay. • For 3 -9 October, above-average rainfall is predicted for centralnorthern Colombia and western and southeastern Brazil. Belowaverage rainfall is predicted over western Colombia, western Peru, southeastern Venezuela, and extreme southern Brazil. For 10 -16 October, above-average rainfall is predicted for eastern Venezuela, Guyana, Suriname, and much of Brazil except the south where belowaverage rainfall is predicted. Below-average rainfall is also predicted over Colombia, Ecuador, Peru, Uruguay, and northeastern Argentina.

Rainfall Total & Anomaly Patterns: Last 7 Days Total Anomaly During the last 7

Rainfall Total & Anomaly Patterns: Last 7 Days Total Anomaly During the last 7 days, below-average rainfall was observed over much of South America (north of 30 S) except for spotty above-average rainfall over portions of central Colombia, northern Peru, northwestern Brazil, Bolivia, and Uruguay.

Rainfall Totals & Anomaly Patterns: Last 30 Days Total Anomaly During the last 30

Rainfall Totals & Anomaly Patterns: Last 30 Days Total Anomaly During the last 30 days, below-average rainfall was observed over much of South America except for spotty above-average rainfall over portions of Colombia, northern Peru, and Bolivia.

Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau BP • 90 -day rainfall

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

Tropical Pacific and Atlantic SST Anomalies Below-average SSTs are present in the equatorial Pacific

Tropical Pacific and Atlantic SST Anomalies Below-average SSTs are present in the equatorial Pacific Ocean, and above-average SSTs are found in the equatorial Atlantic. (For more details of El Niño – La Niña evolutions, 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 24 -30 Sept 2011, in

Atmospheric Circulation Recent 7 days • Upper panels: During 24 -30 Sept 2011, in the upper C A troposphere , anomalous cyclonic circulation (C) was observed over central Brazil and anomalous anticyclonic circulation (center located at A) was observed over the eastern Pacific, central Chile and central Argentina. • Lower panels: Anomalous sinking motion (positive omega) was observed over much of South America except its northwestern and southern portions where anomalous rising motion occurred. 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

925 -h. Pa Wind &Temperature Recent 30 Days Recent 7 Days • During the 7 -day period of 24 -30 September 2011, above-average temperatures were observed over central Brazil and northeastern Argentina. 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 -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 3 Oct 2011 – Days 1 -7

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 3 Oct 2011 – Days 1 -7 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 3 October 2011– Days 8 -14 Total

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 3 October 2011– Days 8 -14 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS MODEL FORECASTS • For Days 1 -7 (3 -9 October), above-average rainfall is

NCEP/GFS MODEL FORECASTS • For Days 1 -7 (3 -9 October), above-average rainfall is predicted for central-northern Colombia and western and southeastern Brazil. Below-average rainfall is predicted over western Colombia, western Peru, southeastern Venezuela, and extreme southern Brazil. • For Days 8 -14 (10 -16 October), above-average rainfall is predicted for eastern Venezuela, Guyana, Suriname, and much of Brazil except the south where below-average rainfall is predicted. Belowaverage rainfall is also predicted over Colombia, Ecuador, Peru, Uruguay, and northeastern Argentina.

Forecast Verification Forecast from 19 Sept 2011 Valid 26 Sept – 2 Oct 2011

Forecast Verification Forecast from 19 Sept 2011 Valid 26 Sept – 2 Oct 2011 Forecast from 26 Sept 2011 Valid 26 Sept – 2 Oct 2011 Observed 26 Sept – 2 Oct 2011

Climatology Rainy Season Dates ONSET DEMISE

Climatology Rainy Season Dates ONSET DEMISE

Precipitation Climatology

Precipitation Climatology

Precipitation Climatology Animation

Precipitation Climatology Animation