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 October 2014 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 • 30 -day rainfall deficits increased over portions of central and southeastern Brazil. • During the last 7 days (6 -12 October 2014), below-average precipitation was observed over most of Brazil. Above-average precipitation was observed over northern Peru, Colombia, Uruguay, and coastal sections of Northeast Brazil (states of Pernambuco and Alagoas). • For 13 -19 October 2014, below-average precipitation is predicted for most of Brazil (between 5 S and 25 S), central and southern Peru, Bolivia and Paraguay. Above-average precipitation is predicted for extreme southern Brazil and Uruguay.

Rainfall Total & Anomaly Patterns: Last 7 Days Total Anomaly During the last 7 days, below-average precipitation was observed over most of Brazil. Aboveaverage precipitation was observed over northern Peru, Colombia, Uruguay, and coastal sections of Northeast Brazil (states of Pernambuco and Alagoas).

Rainfall Totals & Anomaly Patterns: Last 30 Days Total Anomaly During the last 30 days, below-average precipitation was observed over the Amazon Basin in Brazil, eastern Venezuela, Guyana, Suriname, and southeastern Brazil. Above-average precipitation was observed over northern Peru, southern Paraguay, and Uruguay.

Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau BP • 90 -day rainfall deficits are present over the southern Amazon Basin and the Brazilian Plateau. • 90 -day rainfall is near average over southern Brazil.

Tropical Pacific and Atlantic SST Anomalies SSTs are above average in the equatorial Pacific and near average in most of the equatorial Atlantic. (For 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 C • Upper panels: During the period of 4 -10 Oct. 2014, anomalous cyclonic circulation (center indicated by red C) was observed over the western Atlantic and Southeast Brazil. • Lower panels: Anomalous rising motion occurred over eastern Argentina, southern Paraguay and Uruguay. Anomalous sinking motion occurred over central and southeastern Brazil. • 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 4 -10 Oct. 2014, temperatures were below average over eastern Brazil, and above average over Paraguay and extreme northern 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 October 2014 – 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 October 2014 – 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 October 2014), below-average precipitation is predicted for most of Brazil between 5 S and 25 S, central and southern Peru, Bolivia and Paraguay. Above-average precipitation is predicted for extreme southern Brazil and Uruguay. • For Days 8 -14 (13 -19 October 2014), above-average precipitation is predicted for scattered areas in northern South America, and portions of Bolivia, Paraguay, and Uruguay. Below-average precipitation is predicted for southeastern Brazil.

Forecast Verification Forecast from 29 September 2014 Valid for 6 -12 Oct. 2014 Forecast from 6 October 2014 Valid for 6 -12 Oct. 2014 Observed 6 -12 Oct. 2014

Climatology Rainy Season Dates ONSET DEMISE

Precipitation Climatology

Precipitation Climatology Animation