2017-08-28. Hurricane Harvey provides lab for U.S. forecast experiments.

posted Sep 1, 2017, 8:16 AM by Alan Gould
By Paul Voosen, Science. For GSS Climate Change chapter 9 and Energy Flow chapter 7. Excerpt: For years, U.S. forecasters have envied their colleagues at the European Centre for Medium-Range Weather Forecasts (ECMWF) in Reading, U.K., whose hurricane prediction models remain the gold standard. Infamously, the National Weather Service (NWS) in 2012 failed to predict Hurricane Sandy’s turn into New Jersey, whereas ECMWF was spot on. But two innovations tested during Hurricane Harvey, one from NASA and another from the National Oceanic and Atmospheric Administration (NOAA), could help level the playing field. ...Last week, GFDL [NOAA’s Geophysical Fluid Dynamics Laboratory] anxiously watched the developing storm to see how it compared with a test run of the next-generation model. On Thursday, a day prior to landfall, the experiment agreed with the European model that Harvey would plow inland, stall, then head back out over the Gulf of Mexico before making a second landfall near Houston, Texas. That progression, close to what’s happening, helps explain the sustained, catastrophic rainfall that has battered the Texas coast. The GFDL model, called FV3, also correctly forecasted that Harvey would develop a double eyewall—a second circular band of storms around the band enclosing the eye. The model’s zoomed-in view also predicted the extreme rainfall totals seen by Houston some 5 days in advance, says Shian-Jiann Lin, the GFDL scientist who led the development of the code powering FV3.... http://www.sciencemag.org/news/2017/08/hurricane-harvey-provides-lab-us-forecast-experiments