A region of thunderstorms about 1,500 miles southwest of Honolulu is organizing and is expected to become a tropical cyclone this week, the National Hurricane Center branch of the National Weather Service said.
The developing system is likely to strengthen and could be a hurricane as it moves near or over the Hawaiian Islands this weekend, the weather service said.
As of midweek the disturbance had winds below tropical storm strength and lacked a well defined circulation, the agency added.
If winds reach 39 miles per hour east of 140 degrees west longitude the storm would receive the name Iselle, the weather service said, and if genesis occurs west of that line it would be named Moke.
Forecasters said several numerical models cluster the possible track near the path taken by Hurricane Lala, while others place the system a bit farther south of the islands, the office in Honolulu said.
Forecast guidance also indicates a risk of rapid intensification, driven by sea surface temperatures that satellite and buoy data show were about 1 to 2 degrees Celsius warmer than normal south of Hawaii, the weather service reported.
The weather service plans aircraft reconnaissance to collect real time data later in the week to refine strength and track forecasts, the agency said.
Impacts Risks And Forecast Context
Residents were urged to prepare now because the Big Island remains vulnerable after Lala, the Honolulu office said, noting recent flooding and infrastructure damage.
Hurricane Lala dropped more than 3 feet of rain on the Big Island and up to 2 feet on Maui, the National Weather Service said, leaving saturated soils and a heightened flash flood risk.
AccuWeather lead hurricane expert Alex DaSilva described the developing system as a tropical rainstorm to raise awareness and said the core could pass roughly 75 to 100 miles south of the Big Island, depending on initial formation.
AccuWeather meteorologists gave an initial Local StormMax rainfall estimate of 24 inches on the Big Island, while cautioning totals will depend strongly on the exact storm track, DaSilva said.
The weather service noted that El Niño and long term global warming have warmed central Pacific waters and reduced high altitude winds that normally weaken storms, increasing the chance of stronger systems.
The Climate Prediction Center meteorologist Nick Novella said higher than normal tropical cyclone activity is expected across the Pacific through October, and the National Hurricane Center predicts multiple cyclones may form this weekend.
Independent models, including a Google AI forecast used heavily by the weather service, have shifted some guidance closer to Hawaii and project a high end tropical storm or low end hurricane may pass just south of the Big Island.
