Henriette (2013)

A small tropical cyclone developed from a disturbance in the Intertropical Convergence Zone and became a tropical depression on 3 August 2013 about 1,025 nautical miles southwest of the southern tip of the Baja California peninsula. It strengthened to Tropical Storm Henriette on 4 August and moved generally west-northwestward, becoming a hurricane by 6 August. Henriette reached its peak intensity on 8 August while centered about 935 nautical miles east of Hilo, Hawaii, then crossed 140°W into the central Pacific on 9 August and steadily weakened before dissipating on 12 August about 470 nautical miles southwest of Kailua-Kona, Hawaii.

Henriette did not make any landfalls. It remained well over open water during its lifetime and passed several hundred miles south of the Hawaiian Islands; the closest approach noted was about 330 nautical miles south of South Point on the Big Island on 11 August while it was weakening to a tropical depression.

The storm’s maximum sustained winds were estimated at 90 knots (105 mph) at 1800 UTC on 8 August, with a minimum central pressure near 976 mb. That peak intensity corresponds to a Category 2 hurricane on the Saffir-Simpson scale. Because Henriette had a relatively small wind field, its central pressure was higher than typical for a storm of that wind speed.

There were no reports of storm surge or significant coastal inundation associated with Henriette, and no ship reports of tropical-storm-force winds. Rainfall and surge impacts to specific Hawaiian cities or counties were not reported in the official record; the storm remained far enough offshore that notable measured surge heights and rainfall totals were not documented in the report.

No damage or casualties were reported from Henriette. The regions most affected in terms of proximity were open waters of the eastern and central North Pacific and areas south of the main Hawaiian Islands, but the storm caused no reported injuries, deaths, or property damage.

Noteworthy items: Henriette unexpectedly strengthened while moving over relatively cool waters, peaking five days after genesis rather than earlier as forecast. Forecasters initially had trouble predicting its formation, and intensity forecasts tended to underpredict the timing of its peak; however official track forecasts performed better than many guidance models and had lower-than-average track errors for this storm.