Weak La Nina features are evident in the tropical Pacific for November 2024 with the Nino 3.4 SST index for the month slightly negative at about -0.3C and the precipitation anomaly pattern for the month showing some aspects of a typical La Nina. Figure 1 shows the global precipitation map for November 2024, the precipitation anomaly from climatology for the month and the composite La Nina anomaly map for November.  The strong negative anomaly feature along the Equator at about 160°E in the middle panel is similar in location to that in the composite La Nina figure with a narrow fragmented negative feature extending to the east, almost to the coast of the Americas, above the Equator.  To the north of that feature is a variable positive anomaly paralleling the narrow negative feature, indicating a slight northward displacement of the ITCZ.  In the Pacific, further south the anomaly features for this month and the composite also show some correspondence over the mid-latitudes.

Further west over the Maritime Continent, the Philippines and the eastern Indian Ocean, a large area of positive rain anomalies existed in November (Fig. 1, middle panel), again consistent with the La Nina composite.  Tropical cyclones contributed to this large-scale feature significantly, especially in the region of the Philippines.  At one point in the middle of the month four tropical cyclones were prowling the western Pacific and South China Sea, apparently a record for November. When these storms hit land they caused heavy rains and floods, for example in the Philippines.  Flooding and landslides from a weak tropical system also hit northeast Sri Lanka causing 12 deaths and continuing into southeast India.  At the very end of the month heavy rains caused havoc in very southern Thailand and Malaysia.  Even in the South Indian Ocean a tropical cyclone tracked across the area.  And Australia was largely covered by positive rainfall anomalies with heavy rains and flooding in parts of Queensland.  The effect of the large-scale La Nina circulation certainly contributed to the enhanced rainfall in this large region and these accompanying smaller-scale disasters.

Even further west the western Indian Ocean and the Horn of Africa are dry, again matching the La Nina composite.  Otherwise the pattern over Africa with positive anomalies over the tropical eastern portion, with landslides in Uganda, is not seemingly connected to La Nina. The overall pattern correlation between this month’s anomaly pattern and the La Nina composite increased a bit for November, but remained positive, but weak (see Fig. 2).