In DepthAtmospheric Science

A 2-week weather forecast may be as good as it gets

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Science  22 Feb 2019:
Vol. 363, Issue 6429, pp. 801
DOI: 10.1126/science.363.6429.801

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Summary

Since the 1980s, supercomputer-powered weather models have added a new day of predictive power with each new decade. Today, the best forecasts run out to 10 days with real skill, leading meteorologists to wonder just how much further useful forecasts can go. A new study suggests a humbling answer: another 4 or 5 days. A seminal 1969 paper by Edward Lorenz introduced what would later be dubbed the "butterfly effect": The chaotic, nested turbulent flows of the atmosphere would make it impossible to forecast the weather after 2 weeks, he suggested. Until recently, however, global weather models have been unable to render the small-scale cloud-forming processes that drive such chaos. Using the latest operational models from Europe and the United States, researchers have now shown that Lorenz was about right in his prediction.