In one of our nation’s most relentless hurricane seasons in recent history, NOAA research scientists were on the front lines of gathering key data used to help produce forecasts that saved lives and protected property. They also worked behind the scenes pushing the frontiers of weather forecasting skill in storm track, wind speeds and rainfall amounts by running and refining experimental forecast models for the future. New drones are being tested in air and water to assess their ability to gather data that can improve hurricane prediction.
A handful of researchers went into operational mode as the hurricane season began, helping plan flight tracks for NOAA Hurricane Hunter aircraft in coordination with NOAA Aircraft Operations Center personnel and NOAA’s National Weather Service to gather key weather data for NOAA forecast models. NOAA researchers flew aboard NOAA aircraft to collect data for operational as well as experimental forecast models.
[NOAA’s Gulfstream IV-SP hurricane hunter jet at the new NOAA Aircraft Operations Center facility in Lakeland, FL at Linder Field]
“We’re the group that tries to make the forecasts better,” said Frank Marks, director of the Hurricane Research Division, part of NOAA’s Atlantic Oceanographic and Meteorological Laboratory. “Our job is to help collect the observations and get them into the models.”
NOAA’s Hurricane Weather Research and Forecasting (HWRF) model, developed by NOAA Research and NOAA’s National Weather Service, proved to be the best numerical hurricane forecasting model for the strongest winds, providing key predictions of rapidly intensifying winds in Harvey, Irma and Maria. “Until this year, the National Hurricane Center rarely predicted rapid intensification,” said Marks. “This year the National Hurricane Center made seven rapid intensification forecasts, of which six were correct.”
While this shows progress, Marks added that there were many rapid intensification events during the 2017 season that we missed. “We have work to do,” he said. “How we get there will be through ongoing extensive efforts to improve data gathering and coverage, improve how computer models handle extensive amounts of data, and make further improvements to already extremely complex hurricane and weather forecast models.”
Advancing forecast models
The big story of the season was that not only did NOAA issue forecasts with record-setting accuracy, according to preliminary data, but experimental models being developed at NOAA research labs produced impressive results, holding out the promise for important gains in future years. These models will be further tested, refined and transitioned to day-to-day operations. The experimental HWRF demonstrated it could improve track forecasts up to 7 percent when compared with the operational model.
[NOAA senior scientist Stan Benjamin (left) and Acting Assimilation Development Branch chief Curtis Alexander discuss model runs of the experimental High Resolution Rapid Refresh tested during the 2017 Hurricane Season. Credit: NOAA]
Another big performer this year was the experimental Global Forecast System or fvGFS. NOAA is transitioning this new model to operations to become NOAA’s next generation Global Forecast Model. The model is powered by the Finite-Volume Cubed-Sphere Dynamical Core or FV-3, which was developed at NOAA’s Geophysical Fluid Dynamics Laboratory. The fvGFS shows great promise for future improvements of track and intensity hurricane forecasts. The experimental model exceeded all other models in forecasting the track of Hurricane Maria.
NOAA Research’s experimental High Resolution Rapid Refresh or HRRRX also showed great promise for future improvements to NOAA’s only high resolution, hourly updating forecast model that can resolve weather down to the level of individual thunderstorms. Preliminary evaluations showed that HRRRX, developed by NOAA’s Earth System Research Lab Global Systems Division, accurately predicted the path of Hurricane Harvey as well as the location and amount of record rainfall from the storm. It also predicted the timing and location of Hurricane Irma’s landfall 28 hours in advance.
Researchers also deployed two types of unmanned aircraft and underwater drones this hurricane season to gather data that could potentially boost forecast skill.
[NOAA scientists launched torpedo-like drones in the waters off Puerto Rico in July that were at work profiling the churning upper ocean waters during the 2017 hurricanes. Credit: NOAA]
NOAA joined with NASA to fly the unmanned NASA Global Hawk ahead of and above Hurricanes Franklin and Harvey, launching dropsondes that collected data to be assimilated into the operational NOAA Global Forecast System model and HWRF. This year marked the first time that Global Hawk dropsondes were assimilated in real-time into the Global Forecast System model.
Scientists also launched six small drones, called Coyote, from a NOAA WP-3D Orion Hurricane Hunter during Hurricane Maria to collect unique data from within the eyewall in the lower part of the storm where it gains strength from the ocean. The low-level observations of wind speed, wind direction, atmospheric pressure, temperature, moisture, and sea surface temperature provide more detail on hurricane strengthening than dropsondes that record a single point of data. This new information has the potential to provide weather models with information to improve predictions of hurricane intensification.
[NASA/NOAA Team Global Hawk preparing to fly UAS mission with dropsondes into Franklin and Harvey]
NOAA also launched torpedo-shaped underwater drones in the waters north and south of Puerto Rico to better understand how the upper ocean contributes to hurricane intensity. These drones profiled the churning waters as Hurricanes Irma and Maria passed by. “This data will give us an excellent idea of what’s happening in the ocean and will help us verify the ocean models to guide forecasts,” said Marks.
Over the next months, scientists will analyze research from this past season in an effort to improve prediction and preparedness during the 2018 hurricane season.
Edited for WeatherNation by Meteorologist Mace Michaels