Discussion: The Climate Impact Company concern regarding the forecast track of Tropical Depression 9, which is certain to become a Gulf hurricane by early next week, is the more prominent hurricane forecast model HMNI and HWFI forecast track and intensities in the latest 5-day outlook. The forecast track is farther west than the consensus forecast taking this system over a larger fetch of warm Gulf water in 4-5 days (Fig. 1). This farther west track is caused by less steering influence than other models are indicating. Due to the farther west track implying longer duration over the warm Gulf, HMNI and HWFI indicate potential for a category-4 major hurricane (Fig. 2). HMNI intensity forecast is close to a category-5 major hurricane in 132 hours. Surface pressure forecast by HMON/HWRF models are in the 934-943 MB range in the east-central Gulf of Mexico in 126 hours. NOAA/WPC and the ECMWF model are favoring a turn toward Florida which leaves less time for full potential of this storm before reaching a land mass. The concern is the atmosphere warms ahead of the storm more so than indicated by models which slows the turning process due to weaker westerlies.
Fig. 1: Latest tropical cyclone model tracks for Tropical Depression 9. The concern is prominent hurricane forecast model tracks from HMNI/HWFI forecasts.
Fig. 2: Latest tropical cyclone model intensities for Tropical Depression 9. The concern is prominent hurricane forecast model tracks from HMNI/HWFI forecasts.