For Floridians, NOAA is a lifeline during hurricane season. Individuals, governments, and institutions rely on their forecasts to make critical decisions as storms approach. Vizcaya is no exception. The museum uses NOAA’s models to anticipate and prepare for damages and flooding. Vizcaya is also using new technologies to mitigate the devastating effects of storms.

Fortunately, NOAA has a new tool under its belt this summer. The Hurricane Analysis and Forecast System, or HAFS, is the latest in a long line of numerical weather models and the scientists behind it are using it to create ever more accurate forecasts of hurricanes as they develop.

Equations of Motion

For Andrew Hazelton, Ph.D., a typical day at work means logging into a supercomputer to monitor NOAA’s cutting-edge forecasting models like HAFS. Hazelton is a scientist at the Hurricane Research Division at NOAA’s Atlantic Oceanographic & Meteorological Laboratory.

“The atmosphere is governed by equations of motion” Hazelton explained, “weather models are basically a set of computer code that solves those equations.”

HAFS is the result of over 5 years of collaboration between NOAA’s Cooperative Institute for Marine & Atmospheric Studies, the National Weather Service Environmental Modeling Center, and the Atlantic Oceanographic & Meteorological Laboratory. HAFS was tested extensively before it became operational in June of this year.

“Our job is to make the equations better,” Hazelton said.

There is a myriad of factors that affect the development and trajectory of a hurricane including water temperature, wind shear, humidity, and various atmospheric disturbances. Scientists rely on models like HAFS to make approximations about how each of those factors might affect a storm.

“We don’t have a perfect understanding of what the weather is in every place everywhere now.” Hazelton said, “We have to do approximations and there’s different ways you can do those approximations and you have different models do it slightly differently.”

HAFS is unique because the way it makes its approximations is compatible with NOAA’s other weather models like the Global Forecasting System, or GFS. It is part of NOAA’s UFS or Unified Forecasting System.

Hazelton explained that each numerical model has a dynamical core at the heart of its equations.

“The dynamical core is like the engine, it is the main driver of the math equations.”

HAFS’s dynamical core is compatible with the GFS, meaning scientists can collaborate more easily between departments.

“When we make improvements in the GFS we can then directly apply those to HAFS and vice versa,” Hazelton said, “we can all work together and compare notes.”

HAFS is also equipped with what researchers call a moving nest; the capability to generate large amounts of detail in one area of a storm.

“We can’t use that fine detail over the entire Atlantic Ocean because it would take too much computer power,” Hazelton said, “the moving nest follows the storm at high-resolution giving us a detailed look at the structure.”

All of NOAA’s forecasting models are reliant upon accurate weather data. So, Hazelton and his fellow NOAA scientists are constantly collecting information and developing better ways to gather real-time data.

“We work to make our equations better but then we also have to get the starting point better.”

That means when hurricanes approach, researchers fly into the heart of storms on specialized aircraft to collect real-time data. They use a Doppler radar mounted on the tail of the plane, anemometers, thermometers, and a myriad of other instruments to understand what’s happening within a storm.

“That data also goes directly into HAFS and other models to make the forecast better,” said Hazelton.

Accurate forecasting is a combination of the best weather observations with the best numerical models.

“Sometimes we treat observations and models like they’re two separate things,” Hazelton explained, “really they’re very intertwined and you have to get both right to get your forecast right.”

A Test

When Hurricane Idalia made landfall on Florida’s Gulf Coast on August 30th, Hazelton and his team flew into the storm to gather data that was fed into HAFS. It was the first major hurricane to make landfall while HAFS fully operational.

“The operational hurricane models did really well overall with Idalia’s intensity evolution,” Hazelton wrote, “Hopefully all the reconnaissance and tail Doppler radar data assimilation helped with these forecasts.”

It’s good news for Floridians that HAFS performed well during the first major storm to make landfall this season. Accurate storm forecasting allows Floridians to better prepare for hurricanes. Homeowners watch NOAA’s models to choose when to shutter up their doors and windows, and municipal and state governments issue evacuation orders based on NOAA’s predictions.

However, storm forecasting is not without its challenges. A recent article from the Washington Post reported that three of NOAA’s hurricane-hunting aircraft were grounded while Idalia hit. Two were undergoing repairs, and the third; a plane dubbed Miss Piggy, was grounded due to technical problems after multiple flights into Idalia while the storm was offshore.

When it comes to hurricanes, Floridians have learned to hope for the best and prepare for the worst. Idalia was the first major storm to hit our coast this year. Hopefully, it will be the last.

Either way, we will all be relying on NOAA’s teams to give us the best information possible in the coming months. It’s imperative that the forecasts are as accurate as possible, which is why models like HAFS are essential.