The National Weather Service is warning Hawaii to brace for a high‑impact Kona low this week. The system will bring two rounds of torrential rain, flash floods, strong winds, severe thunderstorms, and even mountain snow.
This blog post breaks down what the event could mean for residents and visitors. It explains the meteorological setup and offers practical preparedness guidance.
Two rounds of stormy weather and widespread impacts
The system is expected to deliver two heavy-weather episodes from Tuesday through Saturday. The first round will start on Kauai Tuesday morning and reach Oahu Tuesday night.
Harder‑hit areas could see well over 20 inches of rain through the week. About 10 inches are forecast for Honolulu, with more than 30 inches possible atop the state’s volcanoes.
Peak rainfall rates in the strongest bands may reach 2 to 3 inches per hour. This pace can overwhelm island drainage and trigger major flooding.
A brief lull is anticipated Thursday. An even stronger disturbance is expected Friday into Saturday that could bring additional flood watches and damaging winds.
Severe thunderstorms during the event could produce hail, damaging straight‑line winds, and isolated tornadoes. The thunderstorm risk is initially highest for Kauai and Oahu before expanding statewide.
Significant snow accumulations are possible on the summits of the Big Island volcanoes. The Kona low’s counterclockwise circulation, aided by an anomalous clockwise high to the east, will pull abundant tropical moisture northward into Hawaii.
That same moisture plume is expected to continue northeast into the Pacific Northwest, where a strong Pineapple Express may elevate flood risk early next week.
Key hazards at a glance
- Torrential rainfall and flash flooding across multiple islands, with rainfall rates up to 2–3 inches per hour in the heaviest bands.
- Mountain snow on the summits of the Big Island volcanoes, which can complicate travel and driving conditions at elevation.
- Severe thunderstorms capable of hail, damaging winds, and isolated tornadoes.
- Strong winds that can down trees, power lines, and cause travel disruptions.
- Flood watches and warnings as totals accumulate and complicate drainage in urban and rural areas alike.
Forecast timing and geographic scope
Forecasters project two distinct storm surges with heavy rainfall bands shifting across the state from Tuesday into the weekend. The first surge is expected to begin on Kauai Tuesday morning and reach Oahu by Tuesday night.
The second wave will deliver additional rainfall and wind threats Friday into Saturday. While Honolulu could see near the 10‑inch mark, more intense rainfall totals are possible in other parts of the islands, especially where terrain funnels moisture.
The expected rain, combined with strong winds, raises the likelihood of road closures, rock slides, and flooding along coastlines and in drainage systems.
Island-by-island concerns
Kauai and Oahu face the earliest and potentially strongest thunderstorm activity. The risk is forecast to spread statewide as the event evolves.
In the mountains and higher elevations, heavy snow on Big Island summits could create travel hazards and impact access to some high‑elevation communities. Across the state, the combination of heavy rain, gusty winds, and urban drainage limitations will require heightened caution for outdoor activities, commuting, and emergency planning.
Storm dynamics: why this pattern forms
The Kona low’s counterclockwise circulation, aided by a nearby high to the east, channels abundant tropical moisture northward toward Hawaii. This moisture plume fuels persistent rain and thunderstorm development.
The same weather pattern is forecast to push moisture northeast into the Pacific Northwest, setting the stage for a Pineapple Express that could elevate flood risk early next week in that region as well. This is a reminder that a single atmospheric setup can affect climates across broad swaths of the North Pacific and beyond, underscoring the importance of watching official forecasts closely.
Long-range implications for the Pacific Northwest
The moisture plume associated with the Kona low could carry elevated flood potential into the Pacific Northwest. This creates a separate but related weather hazard for communities there in the days ahead.
Residents from both regions should monitor updated advisories. The connectivity between Hawaii and the mainland West Coast is a hallmark of this episode.
Preparedness and safety guidance
In the face of this high‑end event, preparedness is essential. Stay tuned to official forecasts, watches, and warnings from the National Weather Service and local emergency management.
Clear drainage around property and remove debris that could clog runoff paths. Prepare an emergency kit with essentials and charge devices.
Have a plan for evacuation routes if floodwaters threaten your area. Do not drive through flooded roads, and be aware of rapidly changing weather conditions that can produce sudden flooding or wind gusts.
Exercise caution and heed advisories. Ensure family and community safety as this powerful Kona low unfolds across Hawaii.
Here is the source article for this story: Hawaii to see major rain, flooding from extreme weather pattern