NOAA says La Nina ocean cooling has finally arrived, but it’s weak and may cause fewer problems

A long-awaited La Nina has finally appeared, but meteorologists say the periodic cooling of Pacific Ocean waters is weak and unlikely to cause as many weather problems as usual. La Nina is the flip side of the better-known El Nino. It’s an irregular rising of unusually cold water in a key part of the central equatorial Pacific that changes weather patterns worldwide. The last El Nino was declared finished last June, and National Oceanic and Atmospheric Administration forecasters have been expecting La Nina for months. The head of NOAA’s El Nino team says it’s not clear why this La Nina was delayed, but said it may have been influenced by the world’s oceans being much warmer the last few years.