# Presentation: 424694

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

**Update prepared by**
**Climate Prediction Center / NCEP**
**   ****March 8, 2005**

## Outline

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

## Overview

** **MJO activity during June-October and December 2004-January 2005 resulted in significant variability in the atmosphere (wind, pressure) and Pacific Ocean (surface and subsurface temperature).
-  This activity was associated with periods of significant weakening of the low-level easterly winds over the equatorial Pacific and was related to the initiation of eastward-propagating oceanic Kelvin waves.
-  Westerlies associated with the quasi-stationary area of enhanced convection near the date line initiated a strong Kelvin wave during late January 2005. At this time there is uncertainty concerning the possible influence of this latest Kelvin wave on the surface and subsurface conditions in the eastern equatorial Pacific. Currently, the MJO remains very weak.
-  Statistical model forecasts indicate that MJO activity will remain weak over the next 6-10 day period.

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

**Longitude**

**Time**

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

**Westerly anomalies, which developed over the western equatorial Pacific in early January, expanded eastward through the end of the month and persisted through  February. During the last week, the westerly anomalies have weakened in the vicinity of the date line. However, westerly anomalies have appeared across much of the equatorial Pacific during the first week of March. **

## 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 in the vicinity of the date line. **

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

**Longitude**

**Time**

**The eastward propagation of the positive/negative anomaly dipole over the Indian Ocean and Indonesia (late December 2004-early January 2005) was associated with the MJO.**

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

**Negative OLR anomalies (above-average rainfall) have persisted over the central equatorial Pacific and along the South Pacific Convergence Zone during the last 30 days. Positive OLR anomalies (below-average rainfall) persisted over Indonesia and Australia.  These features are consistent with the positive SST departures in the central eq. Pacific.**

**Low-level (850-hPa) westerly wind anomalies have persisted over the central equatorial Pacific during the last 30 days. A series of tropical cyclones, which developed over low-latitudes in the Southern Hemisphere, affected some of the islands in the South Pacific**

## 200-hPa Velocity Potential Anomalies

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

**Positive anomalies (orange/red shading) indicate unfavorable conditions for precipitation.**

**Longitude**

**Time**

**The eastward propagation of negative anomalies over the Indian ocean and positive anomalies over Indonesia and the Pacific during December/early January was associated with the MJO. **
**Recently, a more stationary pattern has developed. **

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

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

## Heat Content Evolution in the Eq. Pacific

** ****Through 2004 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.**
** ****Between August 2004 and January 2005 Kelvin wave activity weakened and the average heat content (0-300 m) decreased.**
**During February 2005 a stronger Kelvin wave developed.**

**Time**

**Longitude**

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

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

## Potential Global Impacts

** ****No impacts directly attributable to the MJO are expected during the next 1-2 weeks**
** ****Enhanced risk of tropical cyclone activity off the northeast coast of Australia in association with an active South Pacific Convergence Zone (SPCZ)  **

## Summary

** **MJO activity during June-October and December 2004-January 2005 resulted in significant variability in the atmosphere (wind, pressure) and Pacific Ocean (surface and subsurface temperature).
-  This activity was associated with periods of significant weakening of the low-level easterly winds over the equatorial Pacific and was related to the initiation of eastward-propagating oceanic Kelvin waves.
-  Westerlies associated with the quasi-stationary area of enhanced convection near the date line initiated a strong Kelvin wave during late January 2005. At this time there is uncertainty concerning the possible influence of this latest Kelvin wave on the surface and subsurface conditions in the eastern equatorial Pacific. Currently, the MJO remains very weak.
-  Statistical model forecasts indicate that MJO activity will remain weak over the next 6-10 day period.