# Presentation: 358594

## Madden-Julian Oscillation: Recent Evolution, Current Status and Predictions

**Update prepared by**
**Climate Prediction Center / NCEP**
**September 29, 2008**

## Outline

** ****Overview**
** ****Recent Evolution and Current Conditions**
** ****MJO Index Information**
** ****MJO Index Forecasts**
** ****MJO Composites **

## Overview

_**Additional potential impacts across the global tropics are available at:**_** http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ghazards/ghaz.shtml**

** ****MJO activity continues with the enhanced phase beginning to enter the western hemisphere. **
** ****Based on the latest observations and most forecast tools, moderate MJO activity is expected to continue during the next 1-2 weeks.**
** ****During Week 1, the MJO is expected to contribute to enhanced rainfall across Central America, Mexico, and Africa with suppressed rainfall for Indonesia. Wet conditions are expected to continue across Central America and Mexico in Week 2 with dry conditions shifting northeastwards to sections of Southeast Asia and the Philippines. **
** ****The current MJO will increase the likelihood for tropical cyclone development across the eastern Pacific during Week 1 and include parts of the Gulf of Mexico and Caribbean during Week 2. **

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

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

- Note that shading denotes the magnitude of anomalous wind vectors

**Easterly anomalies have decreased across the western Pacific.**

**Westerly anomalies have increased across the Caribbean and Atlantic during the last five days.**

**Westerly anomalies have increased during the last five days across southern Asia and the western Pacific.**

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

_**850-hPa Zonal Wind Anomalies (m s**__**-1**__**)**_

**Longitude**

**Time**

**Westerly anomalies (orange/red shading) represent anomalous west-to-east flow**
**Easterly anomalies (blue shading) represent anomalous east-to-west flow**

**During mid-May, easterlies weakened across the western Pacific associated with moderate MJO activity. **
**Easterly anomalies prevailed across much of the eastern hemisphere from late May into August. **
**Westerly anomalies were evident across parts of the Indian Ocean and Indonesia during the second half of July associated with weak MJO activity.**
**Westerly anomalies associated with the current MJO activity propagated eastward from the Indian Ocean into the Pacific during the past few weeks. **

## OLR Anomalies: Last 30 days

_**OLR Anomalies: Last 30 days**_

**Drier-than-normal conditions, positive OLR anomalies (yellow/red shading) **
**Wetter-than-normal conditions, negative OLR anomalies (blue shading)**

**In late August and early September, dry conditions propagated north while enhanced convection continued across Indonesia. The Atlantic Ocean experienced wet conditions during the period.**
**During mid September, enhanced convection began to shift northeastwards into southern Asia and the western Pacific Ocean. Dry conditions developed across the equatorial Indian Ocean.**
**Very dry conditions are evident across the Indian Ocean and western Indonesia during mid-late September.**

## Outgoing Longwave Radiation (OLR) 

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

**Drier-than-normal conditions, positive OLR anomalies (yellow/red shading) **
**Wetter-than-normal conditions, negative OLR anomalies (blue shading)**
**(Courtesy of the Bureau of Meteorology - Australia)**

**Time**

-   >

**MJO activity was evident during April into early June at varying levels of intensity. The strongest MJO activity occurred as strong suppressed convection organized across the Indian Ocean and shifted eastward during mid-to-late May. **
**Persistent enhanced convection was evident across the western Indian Ocean from mid-June to early August. **
**Moderate MJO activity is evident since late August as enhanced convection developed across the Indian Ocean and shifted eastward. During mid-late September, suppressed convection has shifted into Indonesia.  **

**Longitude**

## IR Temperatures (K) / 200-hPa Velocity Potential Anomalies

_**Positive**_** anomalies (brown contours) indicate unfavorable conditions for precipitation**
_**Negative**_** anomalies (green contours) indicate favorable conditions for precipitation**

**The anomalous velocity potential pattern has become more coherent during the past week. **
**Upper-level divergence has become more organized across the western hemisphere while upper-level convergence remains across the Indian Ocean and now includes parts of the Pacific. **
**This pattern continues to propagate eastward.**

## 200-hPa Velocity Potential 

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

**Longitude**

**Time**

_**Positive**_** anomalies (brown shading) indicate unfavorable conditions for precipitation**
_**Negative**_** anomalies (green shading) indicate favorable conditions for precipitation**

**The MJO was largely incoherent during the month of April. **
**A moderate-to-strong MJO was observed from mid-May through mid-June as eastward propagation was more coherent and longer-lived.**
**After weakening in late June, the MJO strengthened during mid-July.**
**From early-mid August into early September, the MJO was weak as a more stationary pattern was evident. **
**The MJO strengthened in early September and eastward propagation has been observed during the past couple of weeks. **

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

_**200-hPa Vector Wind Anomalies (m s**__**-1**__**)**_

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

**Easterly anomalies continue across parts of the Maritime continent.  **

## 200-hPa Zonal Wind Anomalies (m s-1)

_**200-hPa Zonal Wind Anomalies (m s**__**-1**__**)**_

**Longitude**

**Time**

**Westerly anomalies (orange/red shading) represent anomalous west-to-east flow**
**Easterly anomalies (blue shading) represent anomalous east-to-west flow**

**The MJO was weak or incoherent for much of the period from March through April and upper-level winds indicate generally strong and persistent westerly anomalies near and east of the Date Line. **
**During May and early June, eastward propagation was evident in the upper-level wind field and was associated with the moderate-to-strong MJO activity during this time. **
**Westerly and easterly anomalies associated with the current MJO activity have shifted eastward during the past few weeks. **

## Weekly Heat Content Evolution in the Equatorial Pacific

_**Weekly Heat Content Evolution**__** **__**in the Equatorial Pacific**_

**Longitude**

**Time**

**During September and October, negative heat content anomalies increased markedly across the eastern Pacific Ocean and continued until February 2008.**
**Beginning in February, increasingly positive anomalies developed across parts of the western and central Pacific but have since decreased.  **
**During June and July 2008, positive heat content anomalies encompassed much of the Pacific basin in part associated with a Kelvin wave initiated during May 2008.**
**During August 2008, negative anomalies started to develop east of the Date Line and during September the anomalies have expanded eastward. **

## MJO Index -- Information

**  ****The MJO index illustrated on the next several slides is the CPC version of the Wheeler and Hendon index (2004, hereafter WH2004). **
**Wheeler M. and H. Hendon, 2004: An All-Season Real-Time Multivariate MJO Index: Development of an Index for Monitoring and Prediction, *****Monthly Weather Review,***** 132, 1917-1932. **
**  ****The methodology is nearly identical to that described in WH2004 but small deviations from the BMRC figure are possible at times due to differences in input data and methodology. These typically occur during weak MJO periods.**
**  ****The index is based on a combined Empirical Orthogonal Function (EOF) analysis using fields of near-equatorially-averaged 850-hPa and 200-hPa zonal wind and outgoing longwave radiation (OLR).**

## MJO Index -- Recent Evolution 

_**MJO Index -- Recent Evolution **_

**The MJO index indicates continued MJO activity as the enhanced phase is entering the western hemisphere. **

** ****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**
** ****Distance from the origin is proportional to MJO strength**
** ****Line colors distinguish different months**

## MJO Index – Historical Daily Time Series

**Time series of daily MJO index amplitude from 1995 to present  **
**Plots put current MJO activity in historical context**

## Ensemble GFS (GEFS) MJO Forecast

_**Ensemble GFS (GEFS) MJO Forecast**_

**The GEFS forecasts a continuation of a coherent MJO signal into the Week 2 time period. **

**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**

## Ensemble Mean GFS MJO Forecast

_**Ensemble Mean GFS MJO Forecast**_

**Spatial map of OLR anomalies for the next 15 days **

**Time-longitude section of (7.5****°****S-7.5****°****N) OLR anomalies for the last 180 days and for the next 15 days**

**Figures below show MJO associated OLR anomalies only (reconstructed from RMM1 and RMM2) and do not include contributions from other modes (*****i.e*****., ENSO, monsoons)**

## Statistical MJO Forecast

**Enhanced convection is expected to decrease early during the period across the western Pacific while suppressed convection is forecast to shift northeast from the Indian Ocean to southern Asia and the western Pacific.**

**Spatial map of OLR anomalies and 850-hPa wind vectors for the next 20 days **
**(Courtesy of the Bureau of Meteorology Research Centre - Australia)**

**Figure below shows MJO associated OLR anomalies only (reconstructed from RMM1 and RMM2) and do not include contributions from other modes (*****i.e*****., ENSO, monsoons)**

_**Statistical MJO Forecast**_

## MJO Composites – Global Tropics

- _Precipitation Anomalies (May-Sep)_

- _850-hPa Wind Anomalies (May-Sep)_