There is a 50 percent chance the climatic condition known as La Nina -- which is associated with droughts in East Africa -- will return this year, the UN weather agency said Thursday. \"We are increasing the probability of La Nina from 25 to 50 percent,\" Rupa Kumar Kolli, a climate expert at the World Meteorological Organization said, explaining that the rise was due to recent temperature observations in the Pacific. \"La Nina is associated with drought conditions in east Africa. The last La Nina situation was believed to have caused the drought condition in the greater Horn of Africa,\" he told reporters, referring to the La Nina event which ended in May. He however stressed that meteorological predictions were difficult to make and depended on a variety of local conditions.\"And even if a La Nina situation reemerges, it is very likely it will be a very weak La Nina event,\" Kolli explained. Over 12 million people across the Horn of Africa are reeling from the region\'s worst drought in decades, which led UN in July to declare the first famine this century. According to a WMO press statement, La Nina is characterised by \"unusually cool ocean surface temperatures in ... the central and eastern tropical Pacific.\" The weather pattern was blamed for extremely heavy downpours in Australia, southeast Asia and sSouth America over late 2010 and early 2011, the WMO said in May. Although the ocean temperatures in the Pacific leveled to their long-term, or \"neutral\" conditions that month, \"observations during recent weeks indicate a drift toward the cool side ... in terms of surface as well as subsurface ocean temperatures,\" WMO said today. \"If this cooling persists ... for another few weeks then we will be going into another la Nina situation,\" Kolli said. \"For (the Horn of Africa), this can be understood as a cause for additional alert,\" Kolli added.