HONOLULU — Federal and local forecasters are urging residents across the Hawaiian Islands to closely monitor a developing tropical disturbance in the Central Pacific that currently has a 90% chance of becoming a tropical depression within 48 hours.
What officials are watching
The system, designated an invest and widely called Invest 90E, sits east-southeast of the islands and has grown more defined on National Hurricane Center tracking maps. Larry Kelly, a hurricane specialist with the NHC, wrote in an Aug. 19 tropical outlook that interests in the Hawaiian Islands should "closely monitor the progress of this system."
While numerical forecast guidance still favors a track that keeps the center of the storm south of the state, forecasters with the Honolulu Weather Service office warned that the disturbance is likely to transport tropical moisture into the islands and produce increased rainfall.
"Interests in the Hawaiian Islands should closely monitor the progress of this system," Larry Kelly, hurricane specialist at the National Hurricane Center, wrote in the outlook.
Models, uncertainty and potential impacts
Forecast models are not unanimous. Most keep the center south of the islands, but a subset of model runs — and some respected climate scientists — indicate a scenario in which the system could pass closer to the Big Island. Daniel Swain, a California climate scientist, noted that a "concerningly close approach to the Big Island" could occur and that such an outcome "could seriously affect disaster recovery" should it come near.
Andy Hazelton, an associate scientist at the University of Miami, posted on X that certain model tracks place the disturbance on a similar path to Hurricane Lala, which recently brought high winds and heavy rainfall to the state and continues to shape recovery needs.
The Honolulu Weather Service office emphasized the current uncertainty: the system has not yet developed fully and the forecast is subject to change as it organizes and moves westward toward the islands. The storm's eventual size and proximity to land will determine the degree of impacts, including possible surf increases along exposed shores.
What Hawaii could see
- Increased tropical moisture and widespread rain across windward slopes.
- Flash flooding and mudslide risk in steep terrain, particularly where soils remain saturated after Lala.
- Elevated surf and hazardous marine conditions along exposed coastlines.
Experts warned that even if the system's center remains south of the main islands, moisture wrapping around its circulation could push heavy rainfall into the windward terrain — a mechanism that can produce localized flooding and exacerbate landslide risk.
Timing and naming
Forecasters said development is likely over the next two days. If the disturbance consolidates into a tropical cyclone in the Central Pacific basin, the next available name in the sequence would be Moke.
| Forecast element | Current status |
|---|---|
| Chance of development (48 hours) | 90% |
| Time window noted | Next 48 hours (NHC outlook) |
Local context: recovering from Lala
Any additional tropical moisture or wind will complicate recovery from Hurricane Lala, which recently delivered damaging winds and heavy precipitation across parts of the state. Emergency managers and utility crews remain engaged in post-storm repairs, and forecasters cautioned that even a close approach without a direct strike could impede restoration efforts.
Because the disturbance is not yet a tropical cyclone, forecasts may change as the system strengthens or interacts with steering currents nearer to the islands. The Honolulu Weather Service office urged residents and visitors to monitor official forecasts and be prepared to adjust plans if watches or warnings are issued.
Actionable preparedness measures include reviewing personal emergency plans, ensuring emergency kits are stocked, securing loose outdoor items, and staying informed through trusted sources such as the National Weather Service and county civil defense agencies.
For now, forecasters will continue to update probabilities and track guidance as Invest 90E evolves. Officials stressed that the public should keep checking forecasts over the coming days as details become clearer.
Keoni Kahale is a state correspondent for WE NEWS covering weather and public safety across Hawaii.
