# Presentation: 208803

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

**Update prepared by**
**Climate Prediction Center / NCEP**
**   ****May 29, 2006**

## Outline

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

## Overview 

- The latest observations indicate a continued weak MJO.
- Based on the latest observations and model forecasts, the MJO is expected to remain weak during the next 1-2 weeks.
- Potential hazards/benefits across the global tropics during week 1 include increased chances of above (below) normal rainfall across southern Asia from the Arabian Sea into Southeast China (equatorial Indian Ocean).
- Increased chances of above normal rainfall is expected to shift to the maritime continent during week 2. The threat of above normal rainfall, however, remains across sections of western India.

## 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**

**Equatorial easterly anomalies strengthened  in the western Pacific.**

**Westerly anomalies remained strong in the eastern Pacific associated with anomalous convection.**

**An enhanced Somali jet indicative of early onset to the Indian Monsoon.**

## 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 anomalies over the maritime continent and western Pacific developed in association with enhancement of local convection during the last several days.**

**Westerly anomalies over the eastern Pacific remained strong.**

## 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**

**Eastward propagation of OLR anomalies associated with the MJO was evident from mid-January  through late February**

**Enhanced convection over the maritime continent during the past several days**

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

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

**Enhanced convection in the western Pacific in late-April to early-May has been replaced with drier than normal conditions. **

## 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**

**Time**

**Weak to moderate MJO activity was observed during January and February. **

**The MJO has generally been weak since early March.**

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

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

**Northerly anomalies in the Indian Ocean consistent with the early onset of the Indian monsoon.**

## Heat Content Evolution in the Eq. Pacific

**Above normal heat content expanded into the eastern Pacific during April and May 2006 associated with the latest Kelvin wave. **

**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 signal weakened substantially during the last few days.

## Statistical OLR MJO Forecast

**A statistical MJO forecast indicates a very weak signal during next two weeks.  **

## Global Forecast System (GFS) Week 1 Precipitation Forecast

_**Global Forecast System (GFS) Week 1 Precipitation Forecast**_

**Heavy rainfall extending from the Arabian Sea to just south of Japan.**

## Global Forecast System (GFS) Week 2 Precipitation Forecast

_**Global Forecast System (GFS) Week 2 Precipitation Forecast**_

**Heavy rainfall across the maritime continent and sections of the western Pacific.**

## Potential Benefits/Hazards – Week 1Valid May 30 – June 5, 2006

- Increased chances of above normal rainfall extending from the Arabian Sea to sections of southeast Asia associated with the continued development of the monsoon and intraseasonal variability
- Increased chances of below normal rainfall in the equatorial Indian Ocean associated with the continued development of the monsoon and intraseasonal variability

## Potential Benefits/Hazards – Week 2Valid June 6 – June 12, 2006

- Increased chances of above normal rainfall across the maritime continent and the western Pacific Ocean associated with the continued evolution of intraseasonal variability and local positive SST anomalies
- Increased chances of above normal rainfall in the eastern Arabian Sea and western India associated with the continued evolution of the monsoon.

## Summary

- The latest observations indicate a continued weak MJO.
- Based on the latest observations and model forecasts, the MJO is expected to remain weak during the next 1-2 weeks.
- Potential hazards/benefits across the global tropics during week 1 include increased chances of above (below) normal rainfall across southern Asia from the Arabian Sea into Southeast China (equatorial Indian Ocean).
- Increased chances of above normal rainfall is expected to shift to the maritime continent during week 2. The threat of above normal rainfall, however, remains across sections of western India.