The South American Monsoon System: Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 21 April 2014 For more information, visit: http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/American_Monsoon s
Jan 07, 2016
The South American Monsoon System: Recent Evolution and
Current Status
Update prepared byClimate Prediction Center / NCEP
21 April 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
• Large rainfall deficits persist over the SAMS core region (Brazilian Plateau).
• During the last 7 days (14-20 April 2014), below-average precipitation was observed over northern Northeast and extreme southern Brazil, Uruguay and eastern Argentina, and above-average precipitation was observed over southern Paraguay and portions of southwestern Brazil.
• For 21-27 April 2014, below-average precipitation is predicted for coastal areas of northeastern South America, southern Brazil and northeastern Argentina. Above-average precipitation is predicted for the western Amazon Basin, most of Colombia and central Peru.
Highlights
Rainfall Total & Anomaly Patterns:Last 7 Days
During the last 7 days, below-average precipitation was observed over northern Northeast and extreme southern Brazil, Uruguay and eastern Argentina, and above-average precipitation was observed over southern Paraguay and portions of southwestern Brazil.
Total Anomaly
Rainfall Totals & Anomaly Patterns:Last 30 Days
During the last 30 days, below-average precipitation was observed over the eastern and southern Amazon Basin, Venezuela, western Colombia and Ecuador. Above-average precipitation was observed over southern Paraguay and most of Argentina.
Total Anomaly
BP
Recent Evolution: RainfallLast 90 Days BP: Brazilian Plateau
• 90-day rainfall deficits (100-300 mm) continue over the Brazilian Plateau and the southern Amazon Basin.
• 90-day rainfall totals are near average over southern Brazil.
Tropical Pacific and Atlantic SST Anomalies
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
SSTs are above average in most of the equatorial Pacific. SSTs are near average in most of the equatorial Atlantic. (For details concerning El Niño – La Niña, go to the link below.)
Atmospheric Circulation Recent 7 days
• Upper panels: During the period of 12-18 April 2014, anomalous cyclonic circulation was observed over northeastern Argentina (red C).
• Lower panels: Areas of anomalous rising motion were found over Paraguay and southern Brazil, while anomalous sinking motion, a proxy for suppressed precipitation, was observed over central and northern Chile, central and northeastern Argentina, and Uruguay.
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.
C
925-hPa Wind &Temperature Recent 30 Days Recent 7 Days
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-hPa are usually similar to surface observations. Note: Areas with surface pressure below 925-hPa are masked out.
• During the 7-day period 12-18 April 2014, below-average temperatures were observed over eastern Bolivia, Paraguay, southern Brazil, Uruguay and eastern Argentina.
NCEP/GFS Model Forecasts Bias-Corrected Precipitation
Total
Forecasts from 21 Apr 2014– Days 1-7
Anomaly
Note:Note: Bias correction based on last 30-day forecast error.
NCEP/GFS Model Forecasts Bias-Corrected Precipitation
Total
Forecasts from 21 Apr 2014– Days 8-14
Anomaly
Note:Note: Bias correction based on last 30-day forecast error.
• For Days 1-7 (21-27 Apr 2014), below-average precipitation is predicted for coastal areas of northeastern South America, southern Brazil and northeastern Argentina. Above-average precipitation is predicted for the western Amazon Basin, most of Colombia and central Peru.
• For Days 8-14 (28 Apr-4 May 2014), below-average precipitation is predicted for Northern South America, most of Peru, and southern Brazil. Above-average precipitation is predicted for the southern Amazon Basin, central Brazil and central Argentina.
NCEP/GFS MODEL FORECASTS
Forecast Verification
Forecast from 7 Apr 2014Valid for 14-20 Apr 2014
Forecast from 14 Apr 2014 Valid for 14-20 Apr 2014 Observed 14-20 Apr 2014
ClimatologyRainy Season Dates
ONSETONSET DEMISE
Precipitation Climatology
Precipitation Climatology Animation