Madden Julian Oscillation Reactivates

Fig. 1-2: The 2-week MJO forecast indicates weak-to-moderate phase_7 to phase_8 shift which implies increasing convection in the eastern tropical Pacific Ocean.

Discussion: During Q4/2024 and Q1/2025 the Madden Julian oscillation (MJO) was active. Another weak-to-moderate wave of the convection phase of MJO is forecast into the eastern equatorial Pacific Ocean over the next 2 weeks (Fig. 1). Recent convection in the tropical East Pacific (Fig. 2) should increase given the MJO outlook. During MJO phase_7 (West Pacific) shifting to phase_8 (East Pacific) the U.S. typically is biased warmer and wetter than normal (Fig. 3-4). The MJO shift should sustain the current wet weather pattern biased toward the Central U.S. The MJO shift also favors a wetter pattern in South America while Australia tends drier (Fig. 5). Normally, the southern oscillation (SOI) shifts to negative phase when MJO moves through the equatorial East Pacific as the event has a mini El Nino style climate signature. SOI forecasts indicate the negative phase centered on the 6-10-day period. The effects of the MJO should weaken after 2 weeks.

Fig. 3-5: During mid-to-late spring, MJO phase_7 to phase_8 favors areas of anomalous warmth and wet weather in the U.S. while in the tropics, wet climate support shifts to South America while Australia is usually drier.