Heavy rain, high winds, and dangerous surf expected as storm approaches the islands
Category: Climate & Environment
As the Hawaiian Islands prepare for the arrival of Potential Tropical Cyclone One-C, officials are warning residents to brace for heavy rain, strong winds, and dangerous surf conditions this weekend. The system, which is expected to strengthen into a tropical storm named "Lala," is projected to bring rainfall totals of 5 to 10 inches across much of the island chain, with some areas potentially receiving up to 20 inches. This could lead to life-threatening flooding and mudslides, particularly in steep terrain.
The National Hurricane Center (NHC) issued its first Central Pacific potential tropical cyclone advisory for One-C on August 11, 2026, marking an unusual event as it is the first time such an advisory has been issued for a system forming so close to Hawaii. The storm was located approximately 835 miles east-southeast of Hilo, with maximum sustained winds of 40 mph and moving west at 9 mph. Forecasters expect it to become a tropical storm by Thursday, August 13, 2026.
The meteorological conditions surrounding One-C are particularly favorable for strengthening. The system is forming over warmer waters southeast of Hawaii, which provides energy for development. The upper-level trough that typically enhances wind shear is lifting, reducing the shear and allowing the storm to gain strength. John Bravender, a meteorologist with the National Weather Service, noted, "Since it’s forming so close to the state, where its location southeast of us is over warmer water... it’s providing energy for it to strengthen." This means that even if One-C does not reach hurricane strength, tropical storm-force winds could still pose a serious risk to the islands.
The implications of One-C's approach are serious. Hawaii County Mayor Kimo Alameda emphasized the need for a district-by-district response, saying, "Our island is big, so all the islands can fit in our island!" This localized approach is necessary as conditions can vary significantly across the islands. The storm is expected to impact the Big Island first on Friday, with conditions spreading westward to Maui on Saturday and reaching Oahu, Kauai, Lanai, and Molokai by Sunday.
Heavy rainfall is particularly concerning, with forecasts predicting total accumulations of 5 to 10 inches, and isolated areas could see up to 20 inches. This poses a risk for flooding and mudslides, especially in mountainous regions. The NHC warned that flash flooding could occur well inland and away from the storm’s center, highlighting the widespread potential for impact.
As the storm approaches, officials have indicated that a tropical storm watch will likely be issued for portions of the state by early Thursday. The NHC has reported a high 90 percent chance of formation within the next 48 hours. The storm is predicted to bring peak winds of about 70 mph on Saturday, just below the Category 1 hurricane threshold of 74 mph. Tropical storm-force winds could extend up to 275 miles from the center of the storm, meaning even areas that do not experience a direct hit could still face damaging winds.
In addition to heavy rain and strong winds, the system is expected to generate dangerous surf conditions. Surf heights could reach warning levels of 15 feet or higher along east-facing shores, creating hazardous conditions for beachgoers and marine activities. The NHC has cautioned that life-threatening surf and rip currents are likely, urging residents and visitors to exercise caution.
| Forecast Timing | Location | Expected Conditions |
|---|---|---|
| Friday, August 14 | Hawaii Island | Heavy rain begins, winds increase |
| Saturday, August 15 | Maui | Peak wind speeds near 70 mph, heavy rain |
| Saturday Night to Sunday Morning | Oahu | Potential for tropical storm conditions |
| Sunday, August 16 | Kauai | Continued heavy rain and strong winds |
As the storm continues to develop, the National Weather Service has advised residents and visitors to stay informed and prepared. The impacts of tropical cyclones can be severe, even without a direct landfall. The most recent example is Hurricane Hone, which passed south of the Big Island in August 2024 but still resulted in heavy rain and widespread power outages.
With the tropical cyclone season in full swing and exacerbated by El Niño conditions, this year has already seen an active hurricane season in the Eastern Pacific. The NHC has noted that the season typically peaks in September, with several named storms already recorded.
As Hawaii braces for Potential Tropical Cyclone One-C, the state is reminded of its vulnerability to tropical systems. The unique geographical features of the islands can amplify storm effects, making preparedness and awareness all the more important. Residents are urged to monitor updates from local authorities and the National Weather Service as the situation evolves.
In the words of Mayor Alameda, "If we get to fully activate this emergency center, I just make the call, and it’s going to happen, and we’re all going to be here, hands on deck." This sentiment captures the urgency and readiness that officials are emphasizing as they prepare for the storm's potential impacts.