# Presentation: 360652

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

**Update prepared by**
**Climate Prediction Center / NCEP**
**   ****March 1, 2005**

## Outline

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

## Overview

** ****Through most of 2004 MJO activity has contributed to month-to-month fluctuations in the patterns of equatorial winds and tropical convection.**
** ****This activity has been associated with periods of westerlies in the western Pacific and weaker than average easterlies in the central Pacific which have initiated eastward-propagating oceanic Kelvin waves, contributing to a deeper-than-average oceanic thermocline and an increase in the surface and subsurface temperature anomalies in the central and eastern equatorial Pacific.**
** ****Beginning in early November and extending through mid December the MJO was weak.**
** ****The MJO strengthened somewhat in late December but again weakened in the middle to latter half of January 2005.  Currently the area of enhanced convection located over the date line has remained stationary for the last three weeks, showing little evidence of propagation.  The area of suppressed convection to the west, centered near 120****o****E,  has also remained stationary. **
**Statistical model forecasts of the MJO indicate that MJO activity will remain weak over the next 6-10 day period.   The area of enhanced convection over the date line is expected to remain quasi-stationary.      **

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

**Longitude**

**Time**

**Westerlies (western Pacific) and weaker-than-average easterlies (central/eastern Pacific) (orange/red shading) **
**Stronger-than-average easterlies (blue shading)**

**Over the last several months, westerlies have developed on several occasions across the western equatorial Pacific. Most recently, this occurred in mid January.**

**Westerly anomalies centered over the date line have remained quasi-stationary for the last three weeks.**

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

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

**Westerly anomalies continue to be observed centered over the date line. **

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

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

**Longitude**

**Time**

**The MJO, however, became very weak in early November and remained so through mid December.  **

**Over the last three weeks the area of enhanced convection has remained stationary over the date line.    The area of suppressed convection to the west appears to be stationary centered near 120****o****E.  **

**During October the MJO was active in the Indian Ocean and western Indonesia regions.  **

## 200-hPa Velocity Potential Anomalies 5oN-5oS

**Upper-level convergence (orange/red shading, upper-level divergence (blue). **

**As the MJO strengthened in mid December, upper-level divergence / convergence propagated from the Indian Ocean into the Pacific. **

**The MJO became very weak in early November with little propagation of upper-level convergence and divergence.**

**Time**

**Longitude**

**The regions of upper-level divergence (convergence) have shown little evidence of propagation over the last three weeks.  **

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

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

## Anomalous Depth of the 20°C Isotherm (m) (2°S-2°N)

**Longitude**

**Time**

**Shallower-than-average thermocline (blue shading);                                Deeper-than-average thermocline (orange shading).**

**MJO-related weakening of the equatorial easterly winds initiated eastward-propagating oceanic Kelvin waves in early April, late June, late August and October and has contributed to a deeper-than-average oceanic thermocline in the central and eastern equatorial Pacific.**

**A new Kelvin wave was initiated in mid-February consistent with the strong westerly wind anomalies in the region.   **

## Niño Indices: Recent Evolution

**During February, SST anomalies greater than or equal to +0.5C were restricted to the Ni****ño 4 region. Recently, departures have decreased in all of the Niño regions. **

## Empirical Forecast Based on the Real-time Multivariate MJO index

_**Empirical Forecast Based on the Real-time Multivariate MJO index**_

## Potential Global Impacts

- Impacts in the global tropics:
- (i) Elevated risk of tropical cyclone activity owing to an enhanced South Pacific Convergence Zone (SPCZ).

## Summary

** ****Through most of 2004 MJO activity has contributed to month-to-month fluctuations in the patterns of equatorial winds and tropical convection.**
** ****This activity has been associated with periods of westerlies in the western Pacific and weaker than average easterlies in the central Pacific which have initiated eastward-propagating oceanic Kelvin waves, contributing to a deeper-than-average oceanic thermocline and an increase in the surface and subsurface temperature anomalies in the central and eastern equatorial Pacific.**
** ****Beginning in early November and extending through mid December the MJO was weak.**
** ****The MJO strengthened somewhat in late December but again weakened in the middle to latter half of January 2005.  Currently the area of enhanced convection located over the date line has remained stationary for the last three weeks, showing little evidence of propagation.  The area of suppressed convection to the west, centered near 120****o****E,  has also remained stationary. **
**Statistical model forecasts of the MJO indicate that MJO activity will remain weak over the next 6-10 day period.   The area of enhanced convection over the date line is expected to remain quasi-stationary.      **