Although there has been some “westerly wind burst” activity over the Maritime Continent and extreme western Pacific that might portend the end of the La Nina and even a coming El Nino, the Relative Nino3.4 SST Index (RNino3.4, now the NOAA standard) for January still remained clearly in La Nina territory with a -0.9K value.

For the precipitation map for this January (Fig. 1, top panel) the strongest feature is the heavy rain area northeast of Australia and extending eastward south of the Equator. East of there the ITCZ barely exists along the Equator in the central and eastern Pacific this month.  In the anomaly field (Fig. 1, middle panel) negative anomalies in the central/eastern Pacific and central Indican Ocean, both along the Equator, match with the composite La Nina map (Fig. 1, bottom panel).  But the anomaly pattern over the Maritime Continent is very mixed and the negative values across the tropical Pacific are weaker and less continuous this month than in the January composite.  These last traits may be the results of those westerly wind bursts.

Farther afield ENSO is still playing a role in rainfall disasters in Africa. Although rainfall deficits extend southward from the Horn of Africa, multiple floods in Mozambique and northeastern South Africa claimed hundreds of lives.  And heavy rain in eastern Congo caused a landslide in an “unauthorized” mine causing 200 dead.  Even farther afield was a tropical low event at the North Island of New Zealand with devastating landslides and flooding with daily rain totals of 250 mm.  The La Nina composite shows a matching “expected” positive anomaly there.

For this January the U.S. was mostly dry somewhat matching the La Nina composite.  Although California is now drought free, and January was overall dry, there was some flooding both in the southern and northern parts of the state.  And the winter-time snow drought continued over the Rocky Mountains, with portions of the region (e.g., southwest Colorado) with 50% or less Snow Water Equivalent compared to normal.  This obviously bodes ill for springtime runoff and water availability from the Colorado River.  Over South America the northwest corner was wet, with its eastern half mostly dry.  In central and southern Chile drought-associated wildfires caused serious destruction and 18 deaths.

Over Europe a positive rainfall anomaly runs from over the ocean west of Portugal, over Spain and continuing eastward over the Mediterranean into southern Italy.  This feature was related to multiple cyclonic systems translating across the area producing copious rainfall and flooding, especially in southwest Spain and Sicily.