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 31 October 2016 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 • Long-term rainfall deficits are present over Brazilian Plateau. • During the last 7 days (24 – 30 October 2016), below-average precipitation was observed over portions of the northern South America and central Brazil. Above-average precipitation was observed over central Colombia, portions of northern Brazil and a large area across the central Argentina and southern Brazil. • For 31 Oct – 06 Nov 2016, below-average precipitation is predicted over central Brazil and northern Argentina. Above-average precipitation is predicted for northwestern South America and southern Brazil.

Rainfall Total & Anomaly Patterns: Last 7 Days Total Anomaly During the last 7 days, below-average precipitation was observed over portions of the northern South America and central Brazil. Above-average precipitation was observed over central Colombia, portions of northern Brazil and a large area across the central Argentina and southern Brazil.

Rainfall Totals & Anomaly Patterns: Last 30 Days Total Anomaly During the last 30 days, below-average precipitation was observed over most of the northern South America, western and central Brazil, as well as southern Chile. Above-average precipitation was observed over eastern Colombia, northern Peru, central Argentina and the extreme southern Brazil.

Recent Evolution: Rainfall Last 90 Days BP: Brazilian Plateau BP • 90 -day rainfall deficits are present over the Brazilian Plateau (> 50 mm).

Tropical Pacific and Atlantic SST Anomalies SSTs are below average across central and eastern tropical Pacific, and slightly above average in the tropical 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 A • Upper panels: During the period of 23– 29 Oct. 2016, anomalous anticyclonic flow (center noted by red A) was observed off the coast of southern Brazil. • Lower panels: Anomalous sinking motion was observed over southern Chile and eastern Brazil. Anomalous rising motion was observed across southern Brazil and southern Argentina. • 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 23 -29 Oct. 2016, above-average temperatures were observed over eastern Brazil and below-average temperatures were observed over eastern 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 31 Oct 2016 – Days 1 -7 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS Model Forecasts Bias-Corrected Precipitation Forecasts from 31 Oct 2016 – Days 8 -14 Total Note: Bias correction based on last 30 -day forecast error. Anomaly

NCEP/GFS MODEL FORECASTS • For Days 1 -7 (30 Oct – 06 Nov 2016), below-average precipitation is predicted over central Brazil and northern Argentina. Above-average precipitation is predicted for northwestern South America and southern Brazil. • For Days 8 -14 (07 - 13 Nov 2016), below-average precipitation is predicted over much of the northern half of South America. Above-average precipitation is predicted for central Bolivia and central and northeastern Argentina.

Forecast Verification Forecast from 17 Oct 2016 Valid for 24 -30 Oct 2016 Forecast from 24 Oct 2016 Valid for 24 -30 Oct 2016 Observed 24 -30 Oct 2016

Climatology Rainy Season Dates ONSET DEMISE

Precipitation Climatology

Precipitation Climatology Animation