textproduct: Honolulu

SYNOPSIS

A plume of moisture moving in from the southeast is causing and increase in showers over the eastern half of the state. This moisture will continue to spread westward today. Due to the abundant moisture, brief periods of heavy rain will be possible. Our more typical trade wind pattern will return on Wednesday through the weekend.

SHORT TERM UPDATE

Showers have been numerous this morning across most areas as an area of enhanced moisture moves east to west across the state. Precipitation has been consistent enough and heavy enough to warrant a Flood Advisory for the northeast through southeast coastal areas on Big Island. The enhanced moisture will remain over the islands this afternoon, and an update has been done to increase both the chance of rain and amount of rain for the remainder of today. Otherwise, the previous discussion and forecast describe the weather well, and no other changes are planned at this time.

PREV DISCUSSION

Issued at 302 AM HST Tue Jun 2 2026

A weak surface trough is is moving up the island chain east to west. Latest radar imagery shows numerous showers with some locally heavier pockets moving across the Big Island into Maui County. Showers will continue to spread into Oahu and Kauai as the morning progresses. Moderate trades should keep the focus of showers over windward and mauka locations, however some low-level southeasterly flow is allowing some showers to make into leeward areas. With abundant moisture some brief periods of locally heavy rainfall will be possible during the next 24 hours or so.

Drier conditions return, east to west with the aforementioned surface trough moving west of the area Wednesday into Friday. Trades are expected strengthen on Friday into the weekend. Breezy to locally strong trades with typical windward and mauka showers can be expected.

AVIATION

A surface trough near the islands will continue to enhance shower activity across the state. MVFR and even brief IFR conditions possible within heavier showers. Rain chances are expected to relent by the evening hours. Moderate to breezy trade winds strengthen Wednesday.

Airmet SIERRA for mountain obscuration is in effect for windward Kauai, Oahu, Maui, Molokai, Lanai, and the Big Island. These conditions are expected to last much of the day today as a result of ongoing shower activity.

AIRMET Tango remains in effect for moderate turbulence below 12,000 feet all areas of the state.

MARINE

Fresh to strong easterly trades have returned as a subtropical ridge strengthens north of the islands, resulting in Small Craft Advisory conditions across the typically windier channels and waters around Maui and the Big Island. Additional marine zones, particularly the Maui County Windward Waters and the Kaiwi Channel, may need to be added to the advisory in subsequent packages as the area of strong winds expands. Guidance suggests this pattern will persist through the weekend.

Surf along exposed south-facing shores is trending upward this morning as a fresh long-period south-southwest swell fills in. Nearshore PacIOOS buoys reflect this trend, with peak spectral energy centered near the 18-second band. Offshore observations from NDBC buoy 51002 also indicate increasing energy within these long-period bands, supporting a continued building trend through the day today. Surf heights may approach High Surf Warning criteria of 15-foot faces by late Wednesday as the swell peaks. Thereafter, a gradual downward trend is expected through the latter half of the week.

Surf along north-facing shores will begin to build later today and continue increasing through the second half of the week as a couple of out-of-season northerly swells arrive from broad low pressure centered far north of the state near the Aleutian Islands. Surf heights will likely rise above the seasonal average by Wednesday, then remain elevated through Thursday and Friday before gradually easing over the weekend.

Surf along east-facing shores will gradually build through the week as strengthening trade winds generate increasing short- period wind waves. Surf should return to near seasonal levels by the end of the week.

MARINE

Issued at 302 AM HST Tue Jun 2 2026

Fresh to strong easterly trades have returned as a subtropical ridge strengthens north of the islands, resulting in Small Craft Advisory conditions across the typically windier channels and waters around Maui and the Big Island. Additional marine zones, particularly the Maui County Windward Waters and the Kaiwi Channel, may need to be added to the advisory in subsequent packages as the area of strong winds expands. Guidance suggests this pattern will persist through the weekend.

Surf along exposed south-facing shores is trending upward this morning as a fresh long-period south-southwest swell fills in. Nearshore PacIOOS buoys reflect this trend, with peak spectral energy centered near the 18-second band. Offshore observations from NDBC buoy 51002 also indicate increasing energy within these long-period bands, supporting a continued building trend through the day today. Surf heights may approach High Surf Warning criteria of 15-foot faces by late Wednesday as the swell peaks. Thereafter, a gradual downward trend is expected through the latter half of the week.

Surf along north-facing shores will begin to build later today and continue increasing through the second half of the week as a couple of out-of-season northerly swells arrive from broad low pressure centered far north of the state near the Aleutian Islands. Surf heights will likely rise above the seasonal average by Wednesday, then remain elevated through Thursday and Friday before gradually easing over the weekend.

Surf along east-facing shores will gradually build through the week as strengthening trade winds generate increasing short- period wind waves. Surf should return to near seasonal levels by the end of the week.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Advisory until 6 AM HST Thursday for Big Island South- Big Island Southeast-East Honolulu-Ewa Plain-Honolulu Metro- Kahoolawe-Kauai South-Kauai Southwest-Kona-Lanai Leeward-Lanai South-Maui Central Valley South-Maui Leeward West-Molokai Leeward South-Niihau-South Haleakala-South Maui/Upcountry- Waianae Coast.

Small Craft Advisory until 6 AM HST Thursday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.