![]() Air and water temperatures, wind speeds, humidity and evaporation rates, ocean currents and wave data - even measurements of the movements of foam created by winds atop the ocean - are plugged in to predict where clear skies, thunderstorms, tornadoes, hurricanes, snowstorms and heat waves will occur. The equations use data collected from ground-based weather stations, satellites and other sources. Weather models divide areas of the globe into trapezoid-shaped grids and then use complex numerical equations to predict what’s happening in the atmosphere above those grid spaces, stitching them together to create a broader animated forecast model. NOAA uses its own Hurricane Weather Research and Forecasting model, known as HWRF, to track tropical disturbances in the Atlantic Ocean and Gulf of Mexico. The effort resembles a program that led to the introduction in 2017 of separate storm surge watch and warning messages and color-coded watch and warning maps, and of color-coded maps showing how high potential surge waters might be along areas of the coast.Ī key part of the forecast improvement program is aimed at those now-ubiquitous, colorful animated computer models used to predict hurricanes. Marks is most interested in a new effort to improve the way forecasters use social and behavioral science to communicate risk to the public. Improving the information that forecasters give the public about “pre-formation disturbances,” like the low-pressure system in Georgia that turned into Barry this year. ![]() Reducing by half, over the next five years, the rate of errors in predicting both where a hurricane or tropical storm will go and how strong it will be.Įxtending the time for tropical forecasts to seven days, from the present five days. Meteorologists and scientists with the National Hurricane Center, the Hurricane Research Division and other organizations each year attempt to improve both the forecasts and the public dissemination of forecast information through the Hurricane Forecast Improvement Program. Harvey inflicted more damage in Houston, more than 200 miles away from that initial landfall, dropping more than 60 inches of rain on the huge city. ![]() 25, 2017, as a Category 4 hurricane with top winds of 130 mph, is a good example of a tropical cyclone’s unpredictability. Marks said Hurricane Harvey, which made landfall near Corpus Christi, Texas, on Aug. “And while the average track forecast errors are improving, we still have outliers, and it’s really hard to determine when that will happen, when we will have really big forecast errors.”Īnd, he added, “even a track shift of only 20 miles can make a huge shift in what happens on the ground, such as what happened during Hurricane Michael,” the Category 5 storm that destroyed Mexico Beach, Florida, in 2018. “As the average error continues to get smaller, we almost always see impacts outside the cone,” Brennan said in a phone conversation. The track follows the storm's eye, but storms can be hundreds of miles wide, with storm surge and heavy rainfall affecting areas far from the eye. The result is that the forecast cone, that bubble on the map showing the area at greatest risk of having the storm’s eye pass over it in one, two and three days, has shrunk dramatically.īut the public - and some emergency managers - fail to recognize that a hurricane’s effects often stretch far beyond the cone’s area, even if the forecast track is accurate, said Michael Brennan, who oversees the team of hurricane specialists who write the National Hurricane Center’s forecasts. Other challenges: The storm’s potential to intensify and organize led to a scary storm surge forecast for an unprecedentedly high Mississippi River in New Orleans, and its failure to spin up then caused that threat to disappear.īetween 19, the track error for tropical storms dropped from just over 100 miles to just over 50 miles for 24-hour forecasts, from over 200 miles to 60 miles for 48-hour forecasts, and from more than 300 miles to 100 miles for 72-hour forecasts. The bad, Marks said, was the difficulty in getting people to understand how Barry’s slow intensification made it hard to say when and where the worst rainfall would take place. “With that system, the models were actually picking it up almost a week ahead of time and saying there was going to be something dropping out of Georgia into the Gulf that would become pretty consequential, a hurricane. “I think Barry kind of showed the good and the bad,” Marks said in a recent telephone interview. The problem is driving a new round of revisions to both written and graphic forecasts issued by the National Hurricane Center and the National Weather Service, Marks said.
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