In late July, 2013 Tropical Storm Flossie took direct aim on Hawaii, becoming the first storm to trigger tropical storm-related warnings since August of 2007, when a strong Category 3 hurricane, also named Flossie, made a near-miss on the Big Island.
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite flew over the region on July 29 and captured this true-color image of the storm’s center just north of the “Big Island” at 20:50 UTC (10:50 a.m. Hawaiian Standard Time). Heavy clouds spread towards the southeast, and lighter clouds cover the Big Island, Maui and Molokai. Flossie shows a great deal of asymmetry, with little cloud cover in the northwest quadrant, suggesting that the storm is weakening quickly, and possibly pulling apart.
Just ten minutes after this image was captured, the National Hurricane Center (NHC) reported that the center of Tropical Storm Flossie was located at 20.6 N, 154.9 W, about 65 mi (100 km) north-northeast of Hilo, Hawaii. The storm carried maximum sustained winds of 40 mph (60 km/h), making it a minimal-strength Tropical Storm. Flossie was moving west north-west at 18 mph (30 km/h)at that time, and Tropical storm warnings were in effect for Hawaii, Maui County (including islands of Maui, Molokai, Lanai and Kahoolawe), Oahu, Kauai and Niihau. However, the storm was weakening quickly, due to interference from strong wind shear and interaction with the mountainous terrain.
Despite the close proximity at the time this image was captured, preliminary data released by the National Weather Service suggests that the center of Flossie never made landfall, but came close to Kauai in the early morning hours of July 30. Strong northerly wind shear let to a decoupling of the storm circulation, with deep convection moving southward while the low level center moved to the west-northwest. This separation is suggested in the image, with the bright, thick bank of clouds to the south the area of deep convection, and the circular pattern north of the Big Island of Hawaii marking the low-level center.
By 03:00 UTC on July 30 (5:00 p.m. July 29 HST), Flossie had lost enough strength that the NHC classified her as a Tropical Depression. At 15:00 UTC (5:00 a.m. HST) Flossie had become a post-tropical remnant low, and the NHC issued the final advisory on the system.