Thursday, June 11, 2009

El Niño is coming back

John D. Cox in Discovery blogs: … According to the Climate Prediction Center, it looks like El Niño is coming back. Sea surface temperatures have warmed across the Pacific's midsection during the Spring, and more importantly, a large pulse of subsurface warmth has propagated from west to east. … "These surface and subsurface oceanic anomalies typically precede the development of El Niño," the climate center observed in its monthly discussion of conditions in the region.

While most, but not all, models forecast the development of an El Niño this summer, forecasting these events is still a work in progress. The more compelling evidence comes from the observed data, such as this time diagram showing upper ocean temperatures in the central and eastern Pacific becoming anomalously warm this Spring.

El Niño conditions have a variety of impacts around the globe, although every event is different. Typically, upper-level westerly winds intensify, a circumstance that could suppress the development of some Atlantic hurricanes this summer. During winter, the North Pacific jetstream flattens its trajectory and moves farther south, which usually brings more warm winter storms across Southern California and Southeastern US. The Pacific Northwest often experiences warmer and drier winters.

Real-time data from moored ocean buoys for improved detection, understanding and prediction of El Niño and La Niña. A glimpse of sea surface temperature from June 9, from NOAA's El Nino page.

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