Storm & Security

SPECIAL / REPORT Forecasts Tweaked NOAA's updated outlook calls for a 70 percent chance of an above-normal season. Across the Atlantic Basin for the entire season—June 1 to November 30—NOAA's outlook (which includes tropical storms Andrea, Barry, Chantal and Dorian) projects a 70 percent chance for each of the following ranges: • 13 to 19 named storms (top winds of 39 mph or higher), including • 6 to 9 hurricanes (top winds of 74 mph or higher), of which • 3 to 5 could be major hurricanes (Category 3, 4 or 5; winds of at least 111 mph) These ranges are above the 30-year seasonal averages of 12 named storms, six hurricanes and three major hurricanes. The tropical meteorology forecast team at Colorado State University (CSU) also tweaked its 2013 seasonal forecast in early August. "Information obtained through July 2013 indicates that the remainder of the 2013 Atlantic hurricane season will be more active than the average 1981-2010 season," it reports. "We estimate that the remainder of 2013 will have about eight hurricanes (average is 5.5), 14 named storms (average is 10.5) … [and] three major (Category 3, 4, 5) hurricanes (average is 2.0)." Landfall Expectations While remaining above the long-term averages, both the NOAA and CSU updated forecasts are a bit more moderate than their early season predictions. "We have decreased our seasonal forecast slightly from early April and early June," the CSU update states," due to anomalous cooling of sea surface temperatures in the tropical and subtropical eastern Atlantic." The August updated NOAA outlook is similar to its pre-season outlook issued in May, but with a reduced expectation for extreme levels of activity. Motivating this change, it says, is a decreased likelihood that La Niña will develop and bring its reduced wind shear that would further strengthen the hurricane season. Still, the chances of a hurricane coming ashore are higher than usual this season, the CSU outlook states. "We expect an above-average probability of United States and Caribbean major hurricane landfall." Heading into September, FEMA Associate Administrator for Response and Recovery, Joe Nimmich, adds, "The peak of the hurricane season is almost upon us and it's important to remain prepared for hurricanes through November." Upgraded Supercomputers Newest Tools in Hurricane Forecasting Whizzing through 213 trillion calculations per second, newly upgraded supercomputers at NOAA's National Weather Service now are more than twice as fast in processing sophisticated computer weather models to provide more accurate forecasts further out in time. And as the hurricane season ramps up to its historical peak, forecasters will be armed with an enhanced hurricane model that will improve track and intensity forecasts. Nicknamed "Tide," the supercomputer in Reston, VA, and its Orlando, FL-based backup named "Gyre," operates with a processing power of 213 teraflops (TF) — up from the 90 TF with the computers that preceded them. This higher processing power allows the National Weather Service to implement an enhanced Hurricane Weather Research and Forecasting (HWRF) model. With improved physics and a storm-tracking algorithm, the model has displayed up to a 15 percent improvement in both track and intensity forecasts, compared to last year's version of the model, says NOAA. The upgraded HWRF is also capable of processing real-time data collected from the inner core of a tropical system by 12 the tail Doppler radar attached to its P3 hurricane hunter aircraft, data which are expected to produce even greater forecast improvements. The scientific data and insights that these newly upgraded supercomputers will provide are essential to helping government officials, communities and businesses better understand and manage the risks associated with extreme weather and water events. "These improvements are just the beginning and build on our previous success. They lay the foundation for further computing enhancements and more accurate forecast models that are within reach," said Louis W. Uccellini, Ph.D., director of NOAA's National Weather Service. "Next comes the quantum leap," added Uccellini. Following this round of long-planned upgrades, funding requested in the FY 2014 President's Budge would increase computing power even further to 1,950 TF by summer 2015. "That gives us the necessary computer power to run an enhanced version of our primary forecast model, the Global Forecast System," said Uccellini. STORM & SECURITY PROTECTION / PEOPLE IN THE KNOW 2013

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