Inordinate long session of Triple Dip La Nina is likely to conclude soon. La Nina has already weakened from its peak. Though, La Nina advisory remains in place, but a final advisory is likely to be issued , marking end of La Nina event.
ENSO: During last 4 weeks, -ve SST anomalies have weakened across most of the equatorial Pacific Ocean. Nino indices have already risen above the threshold mark of La Nina on the eastern side. The central Pacific indices of Nino 4 and Nino 3.4 are also likely to breach the threshold mark of -0.5 degree soon.
Warming and cooling of ocean surface is a very slow and gradual process. Abrupt changes are unlikely, particularly at cross over mark of neutral regime.
IOD: SST's are generally close to average across the tropical Indian Ocean basin. The latest IOD index value for the week ending 22nd Jan2023 was -0.19degree. Model projections indicate the IOD to remain within neutral bounds during the winter and pre monsoon season.
MJO: Madden Jullian Oscillation has amplified in magnitude over east-central Indian Ocean. It is evolving slowly during the 1st week. Thereafter, it is likely to propagate eastward towards maritime continent in phase 3 & 4. It is likely to retain strength before finally drifting across Western Pacific. Tropical cyclone activity is favoured in the southern half of Indian Ocean. MJO will also support the cyclonic disturbances, if any, emerging across the Indian Seas, including Bay of Bengal. Northern Australia and Northwest Pacific run the risk of increased stormy activity later during week 3.
Long range predictions indicate gradual warming of Tropical Pacific, to reach ENSO neutral by Feb-Mar 2023. However, accuracy is generally lower for long range forecast made at this time of the year. Therefore, ENSO pattern need to be carefully tracked during the spring season.
