The prominent peculiarities of the winter 2009-10 strongly impacting the weather over most of the Globe are the mature El-Niño and extremely low Northern Hemisphere Annular Mode (NAM). El Niño conditions continued to prevail from November to first half of January in tropical Pacific Ocean with warm sea surface temperature anomalies exceeding 1.5°C over most of the eastern and central region. The December NAM index is equal to -3.41, it is the lowest December NAM index and the second lowest NAM index on the record since 1950, with the lowest index equal to -3.77 being observed in January 1977.

During the period from November through the first half of January 2010, unusually cold signals were observed over most of the Eurasian continent, including Northern Europe, most of Russia, Mongolia, northern and eastern China and Korea. Cold signals were also found in the northern part of Australia, part of Canada, USA, Mexico, and the southern tip of South America. On the other hand, warm and dry conditions were observed over North Africa, southern Australia and Central America. Eastern Canada, Greenland and most of the Arctic region also experienced warmer-than-normal conditions.

Below-average temperatures prevailed in most of Central to East Asia, as well as Chile and southern Argentina since November, while the cold anomaly expanded into Europe in December. Korea, north and east parts of China, and Europe were hit by cold waves and heavy snowfall. While most part of North America and Australia experienced warm conditions in November, there were cold conditions in the US and northern Australia from December till the first half of January.

It has been drier than normal over the northern part of Africa, the Philippines and Central America during the period from November till mid January. In other regions, precipitation conditions were varying. Dry conditions over Mexico, the Maritime continent and the adjoining north Australia in December were replaced by wetter-than-normal conditions towards the end of the period.

There are indications that the current El Niño event is now near its peak. Predictions indicate that the current El Niño is expected to persist through the boreal spring (austral autumn) of 2010 and return to normal conditions there after.

The APCC forecast for February-April 2010 indicates persistent warm conditions over equatorial to southern Africa, the Maritime continent and the Philippines, eastern Australia, Canada, Central America, and tropical South America throughout the whole period. Above-normal temperature is also expected in the region spanning Saudi Arabia to northern Indochina, as well as eastern China during the early part of the February-April season.

There are strong chances to expect below-normal rainfall in northern South America, the Philippines and southern Polynesian Islands from February to April. The western part of Canada, Alaska and eastern Indochina may also experience dry conditions in the early part of the season. On the other hand, wet conditions are likely to prevail in the central to eastern equatorial Pacific, Indonesia, the Caribbean and the Florida key region.