# Presentation: 488689

## Madden/Julian Oscillation: Recent Evolution, Current Status and Forecasts

**Update prepared by**
**Climate Prediction Center / NCEP**
**   ****December 5, 2005**

## Outline

** ****Overview**
** ****Recent Evolution and Current Conditions**
** ****Madden Julian Oscillation Forecast **
** ****Summary**

## Overview

- The MJO remains weak with signals across the global tropics more regional in nature and associated with more localized forcing such as that from SSTs and linkages with the extratropical circulation.
- Enhanced convection is evident across the eastern Indian Ocean, sections of Indonesia, and the far western Pacific Ocean and is associated with a continuation of a quasi-persistent pattern of convection present during the last several weeks. Connections with the extratropics also resulted in areas of enhanced convection across east-central Brazil and southeast Africa. Strong suppressed convection is also observed across Central America and areas of northern South America. Westerly low-level wind anomalies have strengthened in the Indian Ocean and have also expanded eastward to cover sections of Indonesia. These anomalies have aided in the generating of circulations both north and south of the equator during the past few weeks over the eastern Indian Ocean and Bay of Bengal. Easterly wind anomalies in the tropical western Pacific Ocean remain.
- Based on the latest observational evidence and statistical and dynamical forecasts, the MJO is expected to remain weak during the upcoming period.
- Although the MJO remains weak, there are potential global benefits/hazards during the forecast period. During week 1, Hurricane Epsilon is expected to impact the Central Atlantic with heavy rainfall, strong winds, and high seas during the period. An elevated chance of above average rainfall exists across east-central Brazil and southeast Africa as periodic frontal systems continue to interact with tropical moisture in these regions. An elevated chance of tropical cyclone activity exists in the Bay of Bengal associated with continued westerly wind anomalies and a continued environment favorable for convection.
- For both weeks 1 and 2, there is an increased chance of above average rainfall from the eastern Indian Ocean across Indonesia into the western Pacific Ocean as a quasi-persistent pattern of convection associated with above average SSTs and other intraseasonal tropical variability is expected to continue.
- The western Pacific Ocean will need to be closely monitored, both north and south of the equator,  for tropical cyclogenesis throughout the forecast period.

## 850-hPa Vector Wind Anomalies  (m s-1)

**850-hPa Vector Wind Anomalies  (m s****-1****)**

**Note that shading denotes the magnitude of the anomalous wind vectors.**

**Easterly wind anomalies remain across the western Pacific Ocean**

**Westerly wind anomalies have strengthened  across the Indian Ocean and have expanded eastward to cover sections of Indonesia**

## Low-level (850-hPa) Zonal (east-west) Wind Anomalies (m s-1)

**Low-level (850-hPa) Zonal (east-west) Wind Anomalies (m s****-1****)**

**Longitude**

**Time**

**Weaker-than-average easterlies or westerlies (orange/red shading). **
**Stronger-than-average easterlies (blue shading).**

**Equatorial easterly anomalies near and west of the date line have weakened.**

**Equatorial westerly anomalies in the eastern Indian Ocean have shifted eastward during the past ten days **

## Outgoing Longwave Radiation (OLR) Anomalies (7.5°S-7.5°N)

**Outgoing Longwave Radiation (OLR) Anomalies (7.5°S-7.5°N****)**

**Drier-than-average conditions (/red shading) **
**Wetter-than-average conditions (blue shading)**

**Longitude**

**Time**

**Most recently, equatorial OLR anomalies are weak. **

**Weak MJO activity was evident during July and again in September as OLR anomalies propagated eastward from the Indian Ocean to the western Pacific Ocean.  **

**Also, suppressed convection was evident across Central America in late November. **

## Outgoing Longwave Radiation (OLR) Anomalies (2.5°N-17.5°N)

**Outgoing Longwave Radiation (OLR) Anomalies (2.5°N-17.5°N****)**

**Drier-than-average conditions (orange/red shading) **
**Wetter-than-average conditions (blue shading)**

**Longitude**

**Time**

**Enhanced convection north of the equator was mainly located in the Indian Ocean, the Bay and Bengal, and the Arabian Sea during the past ten days**

**Suppressed convection was evident across Central America during late November and early December.**

## Anomalous OLR and 850-hPa Wind: Last 30 days

**Anomalous OLR and 850-hPa Wind: Last 30 days**

**Easterly anomalies in the western Pacific strengthened during the last half of November.**

**During the past 30 days, enhanced convection has been evident across the eastern Indian Ocean and Indonesia.  During the most recent period, convection has weakened across the Maritime Continent **

- 1 DEC 2005

## 200-hPa Velocity Potential Anomalies (5°S-5°N)

**200-hPa Velocity Potential Anomalies (5°S-5°N****)**

**Negative anomalies (green shading) indicate favorable conditions for precipitation.**

**Positive anomalies (brown shading) indicate unfavorable conditions for precipitation.**

**Longitude**

**Most recently, upper-level divergence (green) is confined to sections of Africa, the Indian Ocean, and Indonesia while upper-level convergence (brown) is located in the Western Hemisphere. **

**Time**

**Weak to moderate MJO activity was observed from July into October. **

## 200-hPa Vector Winds and Anomalies  (m s-1)

**Note that shading denotes the magnitude of the anomalous wind vectors.**

**Westerly wind anomalies are evident across much of the Pacific Ocean**

**Strong  anti-cyclonic circulations in the central Pacific Ocean**

## Heat Content Evolution in the Eq. Pacific

**Through 2004 and 2005 there were several cases of eastward-propagating oceanic Kelvin waves (indicated by dashed black lines in the figure).**
**Each Kelvin wave was initiated when the easterlies weakened over the equatorial Pacific in association with Madden-Julian Oscillation (MJO) activity.**
**During February 2005, a strong Kelvin wave (initiated by persistent westerly anomalies near the date line unrelated to the MJO) developed and continued to strengthen during March and reached the South American coast during early April.  Heat content has been above average in the western Pacific since June while cooler water has been observed across the eastern Pacific with an westward extension evident during November. **

**Heat Content Evolution**** ****in the Eq. Pacific**

**Longitude**

**Time**

## MJO Index (Magnitude and Phase)

**MJO Index (Magnitude and Phase)**

- The current state of the MJO as determined by an index based on Empirical Orthogonal Function (EOF) analysis using combined fields of near-equatorially-averaged 850 hPa zonal wind, 200 hPa zonal wind, and satellite-observed outgoing longwave radiation (OLR) (Wheeler and Hendon, 2004).
- The axes represent the time series of the two leading modes of variability and are used to measure the amplitude while the triangular areas indicate the phase or location of the enhanced phase of the MJO. The farther away from the center of the circle the stronger the MJO. Different color lines indicate different months.

- The MJO strengthened in early September with enhanced convection propagating eastward into the month of October at weak to moderate levels
- The MJO remains very weak as the projection from the most recent data is located within the unit circle

## Statistical OLR MJO Forecast

_**Statistical OLR MJO Forecast**_

**The MJO is forecast to remain weak during the next 6-10 days **

## Global Forecast System Precipitation Forecast

_**Global Forecast System Precipitation Forecast**_

## Potential Benefits/Hazards – Week 1

_**Potential Benefits/Hazards – Week 1**_

**1. Hurricane Epsilon will impact the central Atlantic with above average rainfall, strong winds, and higher than normal seas **
**2. An increased chance of above average rainfall across central Brazil**
**3. An increased chance of above average rainfall across sections of southeast Africa**
**4. An increased chance of tropical cyclone activity in the Bay of Bengal**
**5. An increased chance of above average rainfall extending from the eastern Indian Ocean across Indonesia into the western Pacific Ocean**

**5**

**2**

**1**

**4**

**3**

## Potential Benefits/Hazards –Week 2

_**Potential Benefits/Hazards –Week 2**_

**1. An increased chance of above average rainfall extending from the eastern Indian Ocean across Indonesia into the western Pacific Ocean**

**1**

## Summary

- The MJO remains weak with signals across the global tropics more regional in nature and associated with more localized forcing such as that from SSTs and linkages with the extratropical circulation.
- Enhanced convection is evident across the eastern Indian Ocean, sections of Indonesia, and the far western Pacific Ocean and is associated with a continuation of a quasi-persistent pattern of convection present during the last several weeks. Connections with the extratropics also resulted in areas of enhanced convection across east-central Brazil and southeast Africa. Strong suppressed convection is also observed across Central America and areas of northern South America. Westerly low-level wind anomalies have strengthened in the Indian Ocean and have also expanded eastward to cover sections of Indonesia. These anomalies have aided in the generating of circulations both north and south of the equator during the past few weeks over the eastern Indian Ocean and Bay of Bengal. Easterly wind anomalies in the tropical western Pacific Ocean remain.
- Based on the latest observational evidence and statistical and dynamical forecasts, the MJO is expected to remain weak during the upcoming period.
- Although the MJO remains weak, there are potential global benefits/hazards during the forecast period. During week 1, Hurricane Epsilon is expected to impact the Central Atlantic with heavy rainfall, strong winds, and high seas during the period. An elevated chance of above average rainfall exists across east-central Brazil and southeast Africa as periodic frontal systems continue to interact with tropical moisture in these regions. An elevated chance of tropical cyclone activity exists in the Bay of Bengal associated with continued westerly wind anomalies and a continued environment favorable for convection.
- For both weeks 1 and 2, there is an increased chance of above average rainfall from the eastern Indian Ocean across Indonesia into the western Pacific Ocean as a quasi-persistent pattern of convection associated with above average SSTs and other intraseasonal tropical variability is expected to continue.
- The western Pacific Ocean will need to be closely monitored, both north and south of the equator,  for tropical cyclogenesis throughout the forecast period.