Swell Matrix

Area Forecast Discussion

National Weather Service Honolulu Hi

325 am hst Thu Oct 1 2026

Synopsis

Tropical Storm Nolo will gradually accelerate westward away from the state over the next several days. Elevated moisture content being drawn up in the southeast flow will maintain a wetter pattern for Hawaii through the end of the week. Then drier trades are expected to return over the weekend.

Discussion

A wetter pattern is expected to persist across the western half of the state through Friday as Tropical Storm Nolo accelerates westward away from the state and deep tropical moisture is drawn up in the convergent, moderate southeasterly flow. Moderate to heavy showers are expected to continue to stream into mainly Kauai and Oahu from the south, with rainfall rates of 1 to 2 inches per hour. With the rainfall already received since Tuesday night for Kauai and Oahu, the main concern is the potential for nuisance flooding if rainbands train over a particular area and bring persistent heavy rain. Over the last several hours, the moderate to heavy showers have been moving fast enough and have been dispersed enough in areal coverage to avoid the need for flood advisories or flash flood warnings.

As that band of deeper moisture follows Nolo to the west, drier air will be ushered in by moderate to breezy east-northeasterly trade winds this weekend. This will not only minimize the shower activity and confine it to primarily windward areas, but also allow dew points to drop, bringing some relief from the mugginess of the past week.

Early next week, the trades will weaken in response to an approaching surface trough from the northeast and then will weaken further heading into midweek as broad troughing develops northwest of the state. In this lighter flow, land and sea breezes will become increasingly more prevalent with clearing expected overnight and clouds and a few showers developing over leeward and interior areas with daytime heating each afternoon.

Aviation

Moderate southeast winds will continue today and tonight across the state as Tropical Storm Nolo moves away. Showers loosely associated with Nolo will continue to track over Kauai and Oahu today with MVFR conditions likely through the day. Maui County and Big Island will also see occasional clouds and showers through the day.

AIRMET Sierra for mountain obscuration above 2000 feet is in effect for all portions of the smaller islands. This AIRMET will likely continue through today for Kauai and Oahu, and dropped later this morning for Molokai, Maui and possibly Lanai.

Marine

Moderate southeasterly winds will prevail across the region through Friday as Tropical Storm Nolo continues to slowly drift westward away from the Hawaiian Islands. Gentle to fresh east to northeast trades will fill back in across the waters this weekend.

The moderate, short to medium period west to southwest swell originating from Nolo will continue for Niihau and Kauai through Friday night. Additionally, a small background south swell continues for other islands. The next small, long period south swell energy will arrive from Sunday afternoon, peaking on Monday, and then slowly decreasing through Wednesday.

Surf along other shores will remain small until moderate trades return by Saturday, providing a slight boost to east facing shores. Multiple rounds of tiny northwest to north swell energy will reach north and west facing shores starting early next week as the storms tracking near the Aleutian Islands become increasingly active.

Watches, Warnings, Advisories

None.

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