The Madden-Julian Oscillation (MJO) is a key mode of tropical intraseasonal variability with profound effects on global weather and climate. Accurate simulation and prediction of the MJO events are challenging due to its complex propagation characteristics, which are not well-represented in current numerical models. While prior research has associated MJO propagation speed with its zonal scale and suggested it is influenced by sea surface temperature (SST) patterns, our findings indicate that SST does not directly affect the zonal scale and propagation speed. We show that under El Niño-like SST anomalies, atmospheric conditions in the Warm Pool (WP) region become drier and more stable, enhancing shallow cloud formation, and extending the zonal reach and duration of shallow convection. This process moistens and heats the lower atmosphere, thereby increasing the zonal scale and intensity of MJO convection and facilitating its eastward propagation. These results highlight the critical role of shallow convection in the WP region and the need for improved convection parameterization to enhance MJO prediction accuracy.

MJO东传