Southern Hemisphere: Weather & Climate over Major Crops Areas Update prepared by Climate Prediction Center / NCEP 7 October 2009 For Real-time information:

Outline Highlights ENSO Current Status MJO Current Status Monsoons Current Status Southern Hemisphere Circulation Rainfall & Temperature Patterns NCEP/GFS Model Forecast Forecast Verification

Australia: Little to no shower activity was observed across most of the Australian wheat belt during the past 7 days, though eastern South Australia picked up as much as 25mm. The GFS predicts light rainfall across Western Australia, South Australia, and the Queensland/New South Wales borderlands over the next week. Southern Africa: During the past 7 days, no rainfall was recorded in Western Cape, while near- to above-average rainfall fell across South Africa’s maize triangle. The GFS model forecasts abnormally heavy precipitation across central and eastern South Africa during the upcoming week. South America: During the past 7 days, near- to below-average precipitation prevailed across most of South America, bringing relief to states in southern Brazil that have received copious rainfall. The GFS forecasts average to abnormally heavy rains to return to eastern Argentina and southern Brazil, with precipitation also increasing across Brazil’s center west and southeastern regions. Highlights

ENSO Current Status General Summary: El Niño is present across the equatorial Pacific Ocean. Sea surface temperatures (SSTs) were at least 1.0ºC above-average across much of the central and east-central equatorial Pacific. Based on current observations and dynamical model forecasts, El Niño is expected to strengthen and last through the Northern Hemisphere winter During the last 4-weeks (6 Sep – 3 Oct 2009), equatorial SSTs were at least 1.0°C above average across parts of the central and eastern Pacific. For more information go to:

MJO Current Status The amplitude of the MJO index has decreased during the previous week, indicating little to no MJO signal.  The axes (RMM1 and RMM2) represent daily values of the principal components from the two leading modes  The triangular areas indicate the location of the enhanced phase of the MJO  Counter-clockwise motion is indicative of eastward propagation. Large dot most recent observation.  Distance from the origin is proportional to MJO strength  Line colors distinguish different months MJO Index -- Recent EvolutionEnsemble GFS (GEFS) MJO Forecast RMM1 and RMM2 values for the most recent 40 days and forecasts from the ensemble Global Forecast System (GEFS) for the next 15 days light gray shading: 90% of forecasts dark gray shading: 50% of forecasts Yellow Lines – 20 Individual Members Green Line – Ensemble Mean For more information go to: The GEFS forecasts of the MJO index indicate a weak MJO signal continuing through week 1, with a strengthening signal by week 2.

Southern Hemisphere Monsoons Current Status South AmericaSouthern AfricaAustralia During the last 90 days, near- to below-average precipitation occurred across southern and eastern South Africa. For more information go to: Rainfall Anomalies: Last 90 Days During the last 90 days below-average rainfall over the northern Amazon basin contrasted with abnormally heavy frontal precipitation in southern Brazil. During the last 90 days, below- average rainfall dominated eastern Australia’s croplands. Monsoon Season: NOV-APR Monsoon Season: OCT-MAR Monsoon Season: NOV-APR Rainfall Anomalies: Last 90 Days

Southern Hemisphere Circulation 200-hPa, 925-hPa Wind & Temperature Anomalies - Recent 7 days During the 7-day period (29 September—5 October 2009), anomalous 200-hPa troughing was observed over western Australia. Above-average temperatures over interior northeastern Brazil continued, while subnormal temperatures overspread southern Brazil and northeastern Argentina. Cooler than normal temperatures also blanketed the western half of Australia. The average location of cold fronts during this period over South America and Australia are indicated by the dashed blue lines. Low-level (~600 m) wind and temperature anomalies are 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. A A A

Southern Hemisphere Circulation 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. Omega Anomalies and Total Precipitation - Recent 7 days During 29 September—5 October, anomalous negative omega values (rising motion) were observed over portions of eastern South America, south-central Africa, and central Australia. CPC daily gridded precipitation analysis over land only. The daily gauge analysis is created on a 0.5 degree lat/lon over the global land by interpolating gauge observations from ~30,000 stations.

Australia Rainfall Total & Anomaly Patterns Temperature Patterns GFS Forecast

Rainfall Total & Anomaly Patterns: Last 7 Days TotalAnomaly During the previous week, mostly dry weather overspread western Australia. Showers dotted northern croplands in South Australia and Victoria, but drier conditions prevailed across much of New South Wales and Queensland.

Rainfall Total & Anomaly Patterns: Last 15 Days TotalAnomaly During the last 15 days, rainfall was near normal across Western Australia’s farming areas. Above-normal rainfall was observed across South Australia and NW Victoria, contrasting with drier than average conditions in eastern Australia.

Rainfall Total & Anomaly Patterns: Last 30 Days TotalAnomaly During the last 30 days near-to-above-average rainfall from Western Australia through NW Victoria contrasted with abnormal dryness in the east.

Recent Evolution: Rainfall Last 30 Days 30-day rainfall totals are above-average for most of the selected areas over the Australian wheat belt, with the exception of southern Queensland which has been plagued by dryness.

Temperature (°C) Based on GTS Stations (no QC) Extreme Minimum Anomaly Extreme MaximumMean During 30 September—6 October, above-average temperatures where observed across eastern Australia, particularly in southern Queensland, contrasting with subnormal temperatures in the west.

NCEP/GFS Precipitation Forecasts TotalAnomaly For Days 1-7 (7—13 Oct 2009), light precipitation is forecast to overspread Western Australia, South Australia, and croplands around the Queensland/New South Wales border. Forecasts from 7 Oct 2009 – Days 1-7

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 7 Oct 2009 – Days 8-14 For Days 8-14 (14—20 Oct 2009), little to no precipitation is forecast across Australia.

Forecast Verification: Australia Total Anomaly Forecast from 23 Sep 2009 Valid 30 Sep-6 Oct 2009 Forecast from 30 Sep 2009 Valid 30 Sep-6 Oct 2009 Observed 30 Sep-6 Oct 2009 Anomaly Total NOT AVAILABLE

Southern Africa Rainfall Total & Anomaly Patterns Temperature Patterns GFS Forecast

Rainfall Total & Anomaly Patterns: Last 7 Days TotalAnomaly During the last 7 days above-average rainfall fell across interior southern Africa, including northern South Africa.

Rainfall Total & Anomaly Patterns: Last 15 Days TotalAnomaly During the last 15 days above-average rainfall was observed across interior southern Africa, including eastern Nambia and eastern Botswana through southern Zimbabwe.

Rainfall Total & Anomaly Patterns: Last 30 Days TotalAnomaly During the last 30 days above-average rainfall was observed across eastern Nambia and eastern Botswana through southern Zimbabwe. Below-normal rainfall occurred throughout southern and eastern South Africa.

Recent Evolution: Rainfall Last 30 Days 30-day rainfall totals are below-average for most of the selected areas, with the exception of portions of Botswana and Zimbabwe (top left panel). Recent rains in central South Africa have reduced the moisture deficits.

Temperature (C) Based on GTS Stations (no QC) Extreme Minimum Anomaly Extreme MaximumMean During 30 September – 6 October, above-normal temperatures across western South Africa contrasted with subnormal temperatures elsewhere. Minimum temperatures remained well above freezing across primary agricultural areas.

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 7 Oct 2009 – Days 1-7 For Days 1-7 (7-13 October), heavy rains are forecast across portions of central and eastern South Africa. Dry conditions are expected elsewhere.

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 7 Oct 2009 – Days 8-14 For Days 8-14 (14-20 October), rainfall is forecast to shift northward into northeastern South Africa.

Forecast Verification: Southern Africa Total Anomaly Forecast from 23 Sep 2009 Valid 30 Sep – 6 Oct 2009 Forecast from 30 Sep 2009 Valid 30 Sep – 6 Oct 2009 Observed 30 Sep – 6 Oct 2009 Anomaly Total NOT AVAILABLE

Brazil & Argentina Rainfall Total & Anomaly Patterns Temperature Patterns GFS Forecast

Rainfall Total & Anomaly Patterns: Last 7 Days Total Argentina Brazil Anomaly During the previous week, below-average precipitation was observed from the Amazon basin through southern Brazil and eastern Argentina. The dryness was welcome in southern Brazil, which has experienced several weeks of copious rainfall. Heavy rain was limited to Uruguay and extreme southern Rio Grande do Sul.

Rainfall Total & Anomaly Patterns: Last 15 Days Total Argentina Brazil Anomaly During the previous 15 days, generally below- average rainfall in South America contrasted with well above-average rains in southern Brazil. Rainfall overspread portions of Buenos Aires in Argentina, but northwestern farmlands remained dry.

Rainfall Total & Anomaly Patterns: Last 30 Days Total Argentina Brazil Anomaly During the last 30 days unseasonably heavy rains accumulated across southern Brazil and portions of the center west. Below- average precipitation was recorded across the Amazon. In Argentina, wet weather in northern Buenos Aires and southern Cordoba contrasted with drier than average conditions elsewhere.

Recent Evolution: Rainfall Last 30 Days 30-day rainfall totals are above-average over the eastern selected grid-boxes, but below average in interior northern Argentina.

Temperature (°C) - Brazil Based on GTS Stations (no QC) Extreme Minimum Anomaly Extreme MaximumMean During 30 September – 6 October, above-normal temperatures were observed across much of Brazil, with upper-30s extending into western Rio Grande do Sul.

Extreme Minimum Anomaly Extreme MaximumMean Temperature (°C) - Argentina Based on GTS Stations (no QC) During 30 September – 6 October, near normal temperatures overspread Argentina following the previous week’s spring freeze. Below freezing temperatures were limited to portions of southern Buenos Aires.

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 7 Oct 2009 – Days 1-7 For Days 1-7 (7 – 13 Oct 2009), above-average rainfall is predicted to return to southern Brazil, while showers develop across Brazil’s center west and interior northeast. Dry weather is expected across south-central Brazil (Mato Grosso do Sul). In Argentina, rainfall is expected across eastern croplands.

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 7 Oct 2009 – Days 8-14 For Days 8-14 (14 – 20 Oct 2009), heavy rain is expected to sweep across central and southeastern Brazil. Dry weather is forecast for the northeast interior and Rio Grande do Sul. In Argentina, showery weather is forecast to diminish.

Forecast Verification: South America Total Anomaly Forecast from 23 Sep 2009 Valid 30 Sep – 6 Oct 2009 Forecast from 30 Sep 2009 Valid 30 Sep – 6 Oct 2009 Observed 30 Sep – 6 Oct 2009 Anomaly Total NOT AVAILABLE

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