Marine Weather and Tide Forecast for Naalehu, HI

SHORT TERM UPDATE
Trade winds have returned to Kauai and portions of Oahu this evening based on surface weather observation reports. The kona low that produced significant heavy rain, thunderstorms and flash flooding over the Hawaiian Islands over the past four days is roughly 1,200 miles north of the Big Island and continues to move rapidly towards the northeast at 30 MPH away from the state.

The satellite water vapor channel imagery this evening shows a band of deep tropical moisture under the divergent influence of the Sub Tropical Jet lingering over the eastern half of the state. A large are of more stable, subsiding air, continues to drift into the region from the northwest as the high pressure ridge builds in behind the departing kona low. Local scale radar and satellite analysis reveals bands of moderate to heavy rain showers and a few thunderstorms continuing to develop over the coastal waters near the Big Island tonight. These developing shower bands may continue to produce some additional rainfall over the Big Island through Monday morning. Based on these short term weather trends the Flood Watch for the islands in Maui County was cancelled this evening.

The latest short range weather models show the frequency of these developing shower bands will decline on Monday over the Big Island as stabilizing trade winds spread southeastward to all islands by Monday afternoon. That said, a Flood Watch remains in effect through Monday morning for Hawaii County to address the potential threat from any developing smaller scale (mesoscale)
heavy shower bands or thunderstorms. Unless conditions change we will likely cancel the Flood Watch for all islands with the Monday morning forecast package.

PREVIOUS DISCUSSION
Issued at 319 PM HST Sun Mar 22 2026

The kona low will move away to the northeast tonight while the remnant band of moisture covering Oahu to the Big Island stays in place through Monday night. An upper trough moving towards the islands will keep enhanced showers and isolated thunderstorms going into the morning across Maui County and Big Island, and Oahu to a lesser extent. Therefore, will extend the Flood Watch for Maui County and Big Island through the night. The Winter Storm Warning for the Big Island summits will also continue with a few more inches of snow expected above 12000 feet. Numerous, but lighter showers will continue across Maui County and Big Island on Monday.

Trade winds will begin filling in Monday west to east, reaching the Big Island by Tuesday. Once the trades arrive, the leftover clouds and showers from the kona low will shift into a more typical trade wind distribution, favoring windward and mauka areas and much lighter than during the event itself. The moisture clears the islands by Wednesday with drier trade wind weather expected into next weekend.

AVIATION
Residual moisture from the departing kona low has left showers with embedded isolated thunderstorms across much of the Hawaiian Islands, namely from Oahu to the Big Island. Periods of MVFR conditions in these showers, with local LIFR conditions possible.
Otherwise, first indication of trades have returned across the western islands and will spread across the state throughout the forecast period. VFR conditions prevail otherwise.

AIRMET Sierra is in effect for Lanai due to IFR in widespread low ceilings and showers and is expected to continue into tonight.
AIRMET Sierra is also in effect for Oahu, Maui, Molokai, and the Big Island for mountain obscuration due to showers and low clouds. This is also expected to continue into tonight.

AIRMET Zulu remains for light icing in layer 140-FL260 will also persist, mainly over the central portion of the state where the thick high clouds continue to stream over from the southwest.

MARINE
Issued at 319 PM HST Sun Mar 22 2026

Bands of scattered moderate to heavy showers, with an occasional embedded thunderstorm, moving in from the south will primarily impact those waters surrounding Maui County and Big Island. A boundary northwest of the island chain will travel southeast across the state through Monday. Gentle variable to southerly breezes downstream of this boundary will transition to strengthened north northeast winds behind the boundary passage. Moderate trades will become better established early this week, along with widely- scattered light showers, as the upper trough passes east of the state Tuesday.

The northeast swell that peaked yesterday will be on the decline through Monday. A small north swell will reinforce an already established background north swell Tuesday and Wednesday. This will maintain elevated north-facing shore surf the next few days.
Very small south southwest swell will keep south-facing shore surf from going completely flat the remainder of the week. East surf will stay slightly elevated through Monday as result of a fading northeast swell and a little north wrap. East-facing shore short period wind waves will pick up at mid week in response to strengthened trades.

HFO WATCHES/WARNINGS/ADVISORIES
Flood Watch until 6 AM HST Monday for the Big Island of Hawaii.

Winter Storm Warning until 6 AM HST Monday for Big Island Summits of Mauna Kea and Mauna Loa.