Hurricanes: Science and Society: Types of Hurricane Forecast Models

Types of Hurricane Forecast Models

Three-dimensional view of Hurricane Floyd as it approached landfall at Cape Fear on September 16, 1999. Results were obtained from a forecast made using the dynamical Hurricane Prediction System developed at NOAA's Geophysical Fluid Dynamic Laboratory (GFDL). The model correctly forecast the path of Floyd up the East Coast of the United States. In the figure, winds in excess of gale force are indicated by the magenta and white arrows at the surface and top of the storm, respectively. The color shading at the earth's surface represents the precipitation, with red indicating higher intensities. The gray three-dimensional "cloud-like"? feature is the 80% relative humidity surface, cut away on its eastern side to reveal the hurricane's interior structure, including the tube-like eye down the center. The horizontal plane slicing through the middle of the storm, and the red vertical arrows, indicate the upward motion in the storm's interior. Note the north-south asymmetry of the storm, as Floyd gets swept up in the larger-scale southwesterly flow. Image credit: NOAA/GFDL.

While hurricane forecast models vary tremendously in their structure and complexity, they can be separated into a few broad categories. Dynamical models use supercomputers to solve the mathematical equations governing the physics and motion of the atmosphere.
Statistical models are based on historical relationships between hurricane-specific information and the behavior of historical hurricanes. Statistical-dynamical models blend both dynamical and statistical techniques by making a forecast based on established historical relationships between storm behavior and atmospheric variables provided by dynamical models. Trajectory models move a hurricane along a forecasted track based on the large-scale environmental wind field obtained from a separate dynamical model. Ensemble models use multiple forecasts created with different models, different physical parameterizations, or varying model initial conditions to create a single ensemble forecast. Finally, numerical models of storm surge, waves, and coastal flooding are used to forecast
hurricane impacts at landfall instead of hurricane track and intensity.

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