Strong Madden Julian Oscillation Ends La Nina

Highlight: MJO shifts across the Pacific and weakens but may return and shift into the Atlantic in March. The Atlantic shift would signal cold into the East.

Fig. 1-2: Latest 15-day Madden Julian oscillation (MJO) forecast indicates a powerful short-term intensity moving east from the equatorial East Pacific (phase_8) across the Atlantic later this week (phase_1) and weakening moving to the Indian Ocean (phase_3) in 10+ days.

Discussion: The daily southern oscillation index (SOI) is -1.2 which is exceptionally negative especially when compared to the dominant La Nina-like positive phase of the past one year. The shift to negative phase is due to the passage of the convection phase of the Madden Julian oscillation (MJO) through the equatorial East Pacific and onto the Atlantic basin. The MJO strength is exceptional and one of the strongest signatures in recent years. The MJO is forecast to weaken steadily while shifting back to home base in the Indian Ocean later this month. The MJO shift through the eastern equatorial East Pacific has enabled a warm acceleration of Nino SSTA regions and the equatorial Pacific subsurface causing La Nina to abate. The potent MJO shifting eastward supports a shift of the chilly weather in the West U.S. into the East for mid-to-late March. The “atmospheric river” pattern into California should ease after middle of this week with the east shifting MJO. Primary global influences of the MJO episode include a wetter regime across South America, a dry and very warm Australian climate, and some needed rainfall across East India. MJO events generally regenerate every 6 weeks. The next MJO shift across the equatorial Pacific projected for early May is likely to inspire an ENSO shift toward El Nino.