Potential Tropical Cyclone One-C is currently tracking toward the Hawaiian Islands, carrying the threat of heavy rainfall, mudslides, and life-threatening floods across the region.
The National Hurricane Center designated the system—located a little over 1,000 miles east-southeast of Honolulu, Hawaii—as Potential Tropical Cyclone One-C. Forecasters report that the system is expected to strengthen steadily throughout the week and will likely be named Hernan by Friday at the latest. At 11 a.m. EDT Wednesday, the estimated minimum central pressure of the system was recorded at 1003 mb, or 29.62 inches of mercury.
Tracking the Threat to the Hawaiian Islands
Meteorological models indicate that heavy rainfall is set to begin on the Big Island on Friday before pushing into Maui by the start of the weekend. The severe weather is expected to impact much of the remaining Hawaiian Island chain throughout the weekend. Forecasters warn that rainfall totals could range widely between 5 and 10 inches across much of the region, with isolated areas potentially accumulating up to 20 inches.
These torrential downpours carry a significant risk of triggering life-threatening flooding and dangerous mudslides, particularly in mountainous terrain. Because predicting the exact locations that will receive the highest rainfall totals remains difficult, residents and visitors are encouraged to monitor the storm closely over the coming days. Alongside heavy precipitation, gusty outer rain bands could bring winds strong enough to down trees and knock out power lines, though flooding remains the primary hazard.
Climatological Context and Historical Precedent
The Eastern Pacific basin is experiencing an active season, driven in part by a strengthening El Niño event and record-setting sea-surface temperatures. With seven named systems already recorded this region is running roughly nine days ahead of its climatological schedule, where the eighth named storm typically forms by August 21. Previous named storms in this basin have included hurricanes Fausto and Genevieve.
While the National Hurricane Center anticipates PTC One-C to strengthen into a strong tropical storm as it approaches or moves over the islands, hurricane landfall remains a possibility. Historical data from the NOAA Historical Hurricanes Tracks database illustrates how rare direct landfalls at tropical storm strength are in Hawaii. Only two named storms have accomplished this on the island of Hawaii:
- Darby (2013): Peaked as a Category 3 hurricane before making landfall with top sustained winds of 40 mph (64 km/hr).
- Iselle (2014): The island’s strongest recorded landfall, peaking offshore at Category 4 strength before moving ashore with top sustained winds of 60 mph (97 km/hr).
More recently, Hurricane Hone passed approximately 50 miles south of South Point on the Big Island on August 25, 2024, intensifying into a Category 1 hurricane and lashing the area with outer rain bands despite its center staying offshore.
What Comes Next
As Potential Tropical Cyclone One-C continues its westward advance, residents in flood-prone and mountainous zones should review evacuation readiness, secure outdoor items against gusty winds, and stay tuned to official updates as the system develops.
