Multiple Moving Nests in the Hurricane Analysis and Forecast System

NOAA’s Hurricane Research Division developed and tested a real-time parallel configuration of the Hurricane Analysis and Forecast System (HAFS) for the 2024 North Atlantic hurricane season that spans most of the National Hurricane Center’s area for responsibility and permits high-resolution moving nests for up to three concurrent tropical cyclones. This work was done in collaboration with NOAA’s Environmental Modeling Center, supported by NOAA’s Hurricane Forecast Improvement Program (HFIP).

Previous research with Basin-scale HWRF (HWRF-B) showed improvements to track and intensity forecasts when multiple storms are all simulated with high-resolution nests instead of the default single-storm configuration.

We will describe a number of enhancements beyond the HAFS operational version that were made to the model code to enable and optimize the basin configuration. The moving nest code was upgraded to allow parallel storm-following high-resolution nests for multiple storms. Additional changes to improve handling of high-resolution surface datasets were made to reduce the memory footprint for very large parent domains so the model would run on our research cluster.

We will evaluate the performance of the HAFS Multi-Storm (HAFS-M) configuration for a selected multi-storm case, focusing on storm-storm interactions, their influence on improved hurricane predictions, and behavior of the model during potential nest overlaps. We will also test multiple moving nests in a global configuration, with tropical cyclones in different basins each simulated with a high-resolution, storm-following nest.