Lowell Regains Category 5 Ahead of Hawaii Turn

Hurricane Lowell is a Category 5 storm again, and Hawaii is waiting on a turn.

As of the National Hurricane Center's 5 p.m. HST Friday advisory — 11 p.m. ET on Sept. 4 — Lowell had regained Category 5 strength with maximum sustained winds near 160 mph, centered about 600 miles south-southwest of Honolulu and moving west at roughly 7 mph, according to Newsweek and USA TODAY, both citing the advisory.

The center said more strengthening was possible over the following day or so, with gradual weakening expected by early next week. Lowell is forecast to make a sharp turn to the north or north-northeast on Sunday and to pass nearest the western Hawaiian Islands late Monday, Sept. 7, into Sept. 8.

The NHC's official track puts Lowell's center about 150 miles west of Niihau, or roughly 190 miles west of Kauai, Monday afternoon through Monday night, CNN reported. USA TODAY, citing the same forecast cycle, put the closest approach at roughly 200 miles from Kauai between Sept. 7 and 8. At that point forecasters expect Lowell to be near major hurricane strength — near Category 3, per the National Weather Service's Honolulu office.

The center also warned that hurricane watches could be required for parts of the westernmost Hawaiian Islands on Saturday.

This is an update to our Sept. 4 story, Hawaii Under Emergency as Hurricane Lowell Turns North, published when Lowell was a Category 4 and had not yet begun its turn.

The Uncertainty Is Track, Not Strength

Nobody is arguing about how strong Lowell is. The argument is over where it goes.

Ensembles — groups of computer models run together — still span outcomes from a direct, devastating landfall on Kauai or Oahu to a pass more than 500 miles west of Niihau that would deliver little beyond rougher surf and a few showers, according to CNN and the San Francisco Chronicle. A shift of less than 100 miles east of the current forecast track would mean far more direct impacts.

The NHC's own forecast discussion, written by senior hurricane specialist John Cangialosi, said predicting where and how sharply Lowell turns "is challenging" and that the models "show a considerable amount of spread on how close the core of Lowell gets to Kauai County," USA TODAY reported.

The turn is being driven by an upper-level low pressure area well north of Hawaii that is expected to grab Lowell and pull it north — CNN likened it to a claw machine reaching for a stuffed animal. How firm that grip is, and when it closes, decides the whole story. Confidence rises only after Lowell actually completes the turn this weekend.

Steven Businger, a meteorology professor at the University of Hawaii, told USA TODAY the forecast path just west of Kauai is "troubling" because it would put the island in the storm's northern quadrant, where winds are typically most dangerous. "It's a very strong storm," he said. "If it takes the path that the current models are suggesting, then it could be a real problem for Kauai."

On the current track, the Chronicle reported, Lihue has less than a 25% chance of seeing sustained tropical-storm-force winds.

What Hits Regardless

Track or no track, the water arrives.

Swells from Lowell are expected to produce life-threatening surf and rip currents across many of the islands over the coming days, the NHC said. The Chronicle reported forecast wave heights of 8 to 12 feet on south-facing shores of all the main islands, building to 10 to 14 feet by Saturday.

Timing makes it worse: Lowell's closest pass lands near the highest tides of the month, which arrive Monday. That raises the baseline for any flooding. The National Weather Service in Honolulu has warned that major coastal flooding is possible on Kauai, with significant coastal flooding possible on Oahu.

Rainfall forecasts as of Friday: 3 to 6 inches on Kauai and the Big Island with isolated totals above 10 inches; 2 to 4 inches on Maui with isolated amounts to 8 inches; 1 to 2 inches elsewhere with localized totals to 4 inches. The NHC warned of flash flooding and mudslides, particularly in steep terrain.