Analysis of the Impact of Synoptic Surveillance Dropsonde Observations on GFS and HWRF Model Tropical Cyclone Forecasts

The National Hurricane Center routinely tasks the NOAA Gulfstream-IV (G-IV) jet aircraft to deploy dropsondes in synoptic surveillance missions around tropical cyclones that could threaten the United States as a hurricane. These missions are designed to collect data to improve model track forecasts around the time of hurricane watch and warning issuance - 48 and 36 hours before the onset of tropical-storm-force winds, respectively.

In an effort to quantify the impact of the dropsonde data, track forecast errors from the NCEP GFS model and track and intensity forecast errors from the NCEP HWRF model will be compared for model cycles initialized immediately before and after the surveillance missions were flown from 2008 to 2017. Results from this comparison will provide an initial examination of the impact of these supplemental data over a large number of cases.