Paper showing how interactions between NOAA researchers and operational forecasters led to forecast improvements published in The Bulletin of the American Meteorological Society - NOAA's Atlantic Oceanographic and Meteorological Laboratory

This study highlights a successful research-to-operations implementation and evaluation, facilitated by having close connections between the research and operational communities within the National Oceanic and Atmospheric Administration (NOAA). In particular, research at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) led the National Hurricane Center (NHC) to modify flight-track patterns for some aircraft missions around tropical cyclones. A preliminary assessment, which had crucial support from NOAA’s Environmental Modeling Center (EMC), demonstrated that the change has improved tropical cyclone track forecasts.

Figure 1. Possible G-IV flight-tracks (lines) and observation locations (numbered circles) for an imagined Hurricane Andy (a) without an inner circumnavigation and (b) with an inner circumnavigation.

In order to improve computer forecasts of tropical cyclones, the NOAA Gulfstream-IV (G-IV) high-altitude jet has been used since the late 1990s to sample the environment around tropical cyclones with dropwindsondes that measure pressure, temperature, humidity, and wind velocity as they descend to the surface. Since the early 2000s, typical G-IV flight patterns have included releasing dropwindsondes in a single circle about 180 n mi (333 km) from the TC center. However, growing evidence from scientists at AOML suggested that focusing observations closer to the tropical cyclone center would improve track forecasts even more than those further away. Thus, in 2018 NHC modified the flight pattern to include a second circle with a radius of about 90 n mi (165 km) from tropical cyclone centers, and the new pattern has been used in about 65% of missions since then. This article discusses the research-to-operations process that led to the change and how extensively the change has been implemented. The article also discusses a parallel collaboration between AOML and EMC that ultimately resulted in a preliminary assessment of the impact of the change with an experimental version of NOAA’s Hurricane Weather Research and Forecast (HWRF) model.

Figure 2. Average track forecast errors with (green) and without (red) inner-circumnavigation observations. The average percent improvement across all lead times is shown in the bottom right of panel.

■ Important Conclusions:

Growing evidence that focusing observations closer to tropical cyclones led the National Hurricane Center to modify usage of the G-IV high-altitude jet (Fig. 1).

Adding observations from the circle near the tropical cyclone center improves the track forecasts in the HWRF model by about 5% over not having the closer data (Fig. 2).

An important key to this effort’s success was having close connections between the research and operational communities at NOAA.

The study can be found at https://doi.org/10.1175/BAMS-D-23-0084.1. For more information, contact aoml.communications@noaa.gov. Both the OSSE and OSE components of this research were carried out in part
under the auspices of the Cooperative Institute for Marine and Atmospheric Studies (CIMAS), a Cooperative Institute of the University of Miami and the National Oceanic and Atmospheric Administration, cooperative agreement NA20OAR4320472. The OSSE-component funding came from the Quantitative Observing System Assessment Program (QOSAP) and supported the third author (Kelly Ryan). The OSE-component funding came from the FY18 Hurricane Supplemental (NOAA Award ID NA19OAR0220188) and supported the second author (Sarah Ditchek).