HOUR BY HOUR: What to expect as a powerful storm moves over Hawaii

HONOLULU (HawaiiNewsNow) – Your First Alert Weather Team has declared FIRST ALERT WEATHER DAYS through Saturday as a large and powerful Kona storm moves north of the state and continues to pull up deep tropical moisture and heavy rain at times over Hawaii.

The storm is expected to bring an extended period of flash flooding, damaging winds, and strong thunderstorms through at least Saturday.

Expect a combination of threats ranging from significant flash flooding, damaging winds, strong to severe thunderstorms, and snow and ice over the highest Big Island summits.

Southerly to southwesterly winds will be strongest from Friday to Saturday and will produce damaging wind gusts. South shore surf to build Friday into the weekend, likely reaching advisory levels.

View all current weather alerts here.

Hour-by-hour timeline

Here is the latest breakdown of the data from our First Alert Weather team. We will be monitoring this storm throughout the week so check back for updates.

We are entering a second round of severe weather from this storm system, and the threat of flash flooding, damaging south winds, and strong-to-severe thunderstorms will last into the weekend.

Some regions, especially those in the mountains, could easily receive above 10 inches of rainfall.

Friday, March 13

Morning: With the second round being more volatile, the already saturated grounds from the first round will be a big concern. Strong to severe thunderstorms, damaging south winds, and flash flooding are forecast to impact Kauai throughout Friday morning, potentially extending into Friday afternoon. Following the most impactful weather, winds will shift to be more southwesterly over Kauai.

A Flood Advisory was issued, now including Maui County, meaning minor flooding is now occurring. NWS issued a Flood Watch and a Wind Advisory for all districts of Hawaii Island just before 7 a.m.

Afternoon: The deep tropical moisture is forecast to impact Oahu starting around midday and extend through the afternoon. Strong to severe thunderstorms, damaging south winds, and flash flooding will impact Oahu.

Night: The thunderstorms over Oahu will extend into the late evening and through the night. This slow-moving band of thunderstorms could lead to large amounts of rainfall dropping without much time for drainage, increasing the threat of flash flooding. Potentially damaging south winds will continue.

Saturday, March 14

Morning: The deep plume of tropical moisture will march towards Molokai and Lanai early Saturday morning. The most impactful weather will reach Maui by early morning to midday on Saturday. Again, winds will shift to be more southwesterly behind the line of thunderstorms for Oahu and Kauai. Lingering showers will be present for the western half of the state.

Afternoon: Thunderstorms will be present over the eastern half of the state throughout Saturday afternoon. The initial band of thunderstorms could stall over eastern Maui Saturday afternoon and evening.

Pop-up and more scattered thunderstorms are expected for Hawaii Island. However, strong south winds are still expected throughout Saturday for Hawaii Island. Current models hint at higher rainfall totals for the Kona side of Hawaii Island.

Night: The stalled band could remain between Maui and Hawaii Island throughout the night, exacerbating the flooding risk.

Sunday, March 15

The flooding threat will start to decrease for Kauai and Oahu throughout Sunday. However, the ground will be so saturated that any additional rainfall could lead to quick runoff and flash flooding.

Flash flooding and breezy southwest winds are still expected for Maui County and Hawaii Island on Sunday, potentially extending into Monday for Hawaii Island.

RELATED COVERAGE

Download the HNN Weather app from the Apple App Store or Google Play for the latest updates from your First Alert Weather Team: chief meteorologist Jennifer Robbins, meteorologist Drew Davis, and weather anchors Guy Hagi, Ben Gutierrez, and Billy V.

Copyright 2026 Hawaii News Now. All rights reserved.