Ana — 2014

A compact area of thunderstorms south of 145°W organized into a tropical depression on October 13, 2014, and became Tropical Storm Ana on October 14. Ana moved generally west-northwest toward the main Hawaiian Islands, strengthened to a hurricane on October 17, reached its first peak on October 18 about 120 miles southwest of the Big Island, then passed just south of the island chain. After moving well west of the islands, Ana turned westward, then recurved and moved northwestward, briefly restrengthening to hurricane status again on October 25 before becoming extratropical on October 26. The storm’s best track spans 13–26 October and set a Central Pacific record for track length for a system originating in that basin. Ana did not make a direct landfall on any of the main Hawaiian Islands. The storm passed closest to the Big Island and then within about 60 miles of Niihau in Kauai County as it moved west of the islands. No official tropical-storm-force winds were recorded on the islands, and all tropical watches and warnings for the main Hawaiian Islands were cancelled by October 20 (the hurricane watch for some remote monument areas west of Kauai remained briefly longer). Peak intensity for Ana was 75 knots (85 mph) with a minimum central pressure of 985 mb at 0600 UTC on October 18, which corresponds to a Category 1 hurricane on the Saffir–Simpson scale. Ana briefly regained hurricane strength again on October 25 while well west of the main islands, reaching around 65 knots (75 mph) several times before weakening and transitioning to an extratropical low on October 26. Storm surge effects were modest near the islands; no widespread surge measurements of hurricane magnitude were recorded in the report. Rainfall was the primary local hazard: storm totals included just under 12 inches across parts of the main Hawaiian Islands, with some spots on Oahu and the Big Island reporting totals exceeding 11 inches, just over 6 inches at Mount Waialeale on Kauai, and more than 3 inches across portions of Maui County. Radar-derived totals showed a swath of 15+ inch totals as close as about 20 miles southwest of Oahu during the heaviest period. There were no recorded casualties associated with Ana and no real-time reports of wind damage across the main islands. An anecdotal report made nearly a month later described extensive vegetation damage on southern Niihau consistent with tropical-storm-force winds, but this was not an official government-observed damage report. The greatest impacts were heavy rains that produced local flooding and road closures (for example, closure of the main highway through Kawa Flats on the Big Island and localized flooding in Honolulu near Ala Moana Mall). Noteworthy aspects include Ana’s unusually long, record-setting track for a Central Pacific–origin storm (over 50 best track points) and its brief re-intensification to hurricane strength over anomalously warm ocean waters after recurvature. Forecasts and warnings by the Central Pacific Hurricane Center were timely and generally performed well; CPHC track and intensity forecasts for Ana had smaller errors than their recent five-year averages, and some local forecasts outperformed consensus guidance during the island-approach period.