Neki — 2009

Neki formed as a tropical depression about 635 nautical miles south of South Point, Big Island, Hawaii, late on 18 October 2009. It moved generally west-northwest then northwest as it strengthened, turned north and then northeast as an upper-level trough eroded the steering ridge, and finally executed a small loop before drifting northwest and degenerating into a remnant low on 27 October. The system spent its life entirely over open waters of the central Pacific and passed through the Papahānaumokuākea Marine National Monument area on 23–24 October. Neki did not make any landfalls on inhabited main Hawaiian Islands. It passed within about 60 nautical miles of French Frigate Shoals around 0000 UTC 24 October and came within about 11 nautical miles of uninhabited Necker Island at 0600 UTC 24 October. Because the threatened islands and atolls were very low-lying, evacuations were carried out: 10 personnel were flown off Tern Island (French Frigate Shoals) on 21 October and several people were removed from Laysan Island on 22 October. The hurricane reached its maximum intensity at 0000 UTC on 22 October with peak sustained winds of 110 knots (125 mph) and a minimum central pressure assessed at 950 mb, making it a Category 3 hurricane at peak. After peak, increasing wind shear and interaction with the upper-level trough caused steady weakening to tropical storm strength by 23 October and to a depression by 26 October. There were no reports of storm surge or notable rainfall impacts on populated areas in the central Pacific; Neki stayed over open water and affected mainly uninhabited atolls. The official report did not list measured surge heights or significant rainfall totals at named cities or counties. The most directly affected places were remote features of the Papahānaumokuākea Marine National Monument such as French Frigate Shoals, Necker Island, and Laysan Island. No deaths or damage were reported in association with Neki. Protective actions included the evacuations of personnel from Tern Island and Laysan Island due to the islands’ vulnerability. Forecasts anticipated Neki’s development reasonably well, but the storm’s erratic track increased forecast errors—track guidance and official forecasts showed larger-than-average errors beyond about 48 hours for this system.