Mature La Nina continues to run in the tropical Pacific, without any visible signs of easing out soon. On the other hand, Indian Ocean Dipole seems to have finished the run and turned neutral.
ENSO: Near stationary pattern of below-average sea surface temperature (SST) has prevailed in the equatorial Pacific, since July 2022. Low-level easterly wind anomalies and upper-level westerly winds over the equatorial Pacific are quite consistent with the ongoing La Nina pattern. Though there are some distant signs of weakening of trade winds, the coupled ocean atmosphere continues to reflect La Nina. It is expected to ease out early next year. The Oceanic Nino Index (ONI), the principal index for monitoring La Nina remains unwavering and continues to be below the threshold of -0.5 deg.
All the Nino indices are steadily holding below the threshold. Nino 1+2 is fluctuating more possibly because of the proximity of the coastline.
IOD: Negative IOD index continues to plunge for the 4th consecutive week with the index value ranging between -0.4 deg and 0.0 deg. The negative IOD index has lasted for 5 months from June to Oct 2022. The most recent value for the week ending 27th Nov was -0.03 deg. The breakdown is coinciding with typical IOD events and is consistent with the expected pattern. The anomalies of warm and cool temperatures have nearly dissolved and the SSTs are close to average across the northern half of the Indian Ocean.
MJO: Increased Madden Jullian Oscillation activity is expected to continue for one more week. MJO is currently sailing over Western Hemisphere, closer to African Continent. It is likely to remain in phase-I, albeit with reduced amplitude but still favourable for enhanced convective envelope across the Indian Seas. MJO amplitude is likely to decrease further, as it shifts away towards Maritime Continent in phase IV.
IOD has completely diffused now and will remain inconsequential for the ongoing northeast monsoon activity. La Nina conditions are not favourably related to the winter rainfall over South Peninsula. Northeast Monsoon rainfall has been inadequate in the month of November over South Interior Karnataka, Rayalaseema and Coastal Andhra Pradesh. For the 2nd successive year, the Indian Seas remained storm-free in November.
