textproduct: Honolulu

SYNOPSIS

Surface high pressure strengthens to the northeast of the state today and will bring an increase in trade wind flow. In addition, expect an uptick in low cloud cover and shower activity through early Monday over windward portions of Maui, Molokai, and Oahu as an area of enhanced moisture moves in from the east. From late Monday through Friday, light easterly winds will return to the region. Afternoon coastal sea breezes should help to focus scattered clouds and isolated showers over mainly interior and mountainous locations. For the latter part of the week, deeper moisture moving in from the southeast could bring increased precipitation chances to the Big Island.

SHORT TERM UPDATE

Two new items to address: A High Surf Warning has been issued due to the combination of swell and high tide, and a special weather statement has been issued because the volcano has erupted (episode 49). Additional details are available in the associated products.

Otherwise, showers were moving across much of Oahu and parts of Maui County this morning due to a small band of moisture moving in from the east. Winds were mostly northeast at 5 to 15 mph, with occasional gusts around 20 mph in the typical windier locations. Trade winds are still expected to slowly increase in speed later today, and increase a little bit more tomorrow.

PREV DISCUSSION

Issued at 347 AM HST Sun Jun 14 2026 Latest RADAR and IR satellite imagery loop from this morning showed a band of enhanced low clouds and showers moving into Maui County from the east. For the most part, this activity has been light, though some brief pockets of heavier showers have been noted. A few stations on the West Maui mountains picked up just over half an inch of rainfall accumulation over the past 6 hours, but most windward sites reported less than a quarter inch. Through the remainder of this morning, surface high pressure will gradually build well northeast of the state and allow trade winds to strengthen into the moderate range. By this afternoon, these trades should help to drive the aforementioned area of enhanced low clouds and showers westward over Oahu. A model time-height cross-section over Oahu shows the capping marine boundary temperature inversion height deepening to around 8000 to 9000 feet. Though most activity will affect windward sides of the island, the moisture level should be deep enough to allow for some showers to briefly spill over the terrain and onto leeward sides. For the Big Island, expect leeward showers to once again develop over the South Kona slopes in this afternoon during peak diurnal heating. By tonight, showers should be confined to windward areas on most islands as moderate trades and residual moisture from the earlier band begin to exit the region.

Late Monday through Wednesday afternoon, the surface high weakens and moves north, once again allowing a return of light to locally moderate easterly background flow. Scattered afternoon low clouds and isolated showers will likely be limited to the interior of islands and over elevated terrain as diurnally driven sea breezes prevail. During the nights isolated showers may affect windward locations, but nothing of significance.

Late Wednesday through Friday, both the GFS and ECMWF have been consistent over the last several model runs in advecting an area of deeper moisture up from the southeast towards the Big Island. This moist layer, roughly 10000 to 12000 feet deep by current model estimates, would help enhance shower activity initially over the Big Island, then Maui county if it holds together.

AVIATION

Moderate and stable trades are expected for the period. Low-level moisture embedded within the trades may make for light showers and localized MVFR conditions at times, mainly for Maui County and Oahu, otherwise VFR conditions are expected.

AIRMET Sierra is in effect for mountain obscuration across windward Oahu and Maui County due to the aforementioned light shower activity. This is expected to improve later today, however.

A sharp, though weak, upper level trough is producing moderate turbulence aloft over the Big Island, where AIRMET Tango is in place above FL300.

MARINE

A large long-period south-southwest (200 degree) swell will continue to fill in today and peak tonight into Monday before gradually declining through the rest of the week. Latest buoy readings continue to show a gradual upward trend with buoy 51002 showing swell heights of around 4 to 6 feet at 19 to 20 seconds. The large south-southwest swell combined with King Tides will create the potential for significant wave run up along south and west facing shores this afternoon and Monday afternoon. Due to the potential for significant wave up, the High Surf Advisory was upgraded to a High Surf Warning for areas exposed to the south- southwest swell.

Very little swell energy is arriving along north facing shores, keeping surf tiny to flat. A small bump in surf is possible for north- facing shores on Tuesday with the arrival of a small northwest swell and a smaller north swell. Gentle to moderate east-northeasterly winds expected through next week will keep surf along east facing shores below seasonal average.

A Coastal Flood Statement remains in effect for minor coastal flooding of vulnerable low-lying coastal roadways, docks, boat ramps and other coastal infrastructure. King Tides combined with water levels that are running higher than predicted will lead to minor flooding potential around the daily peak tide, which will be during the late afternoon and early evening hours, through at least Tuesday. While minor coastal flooding is expected along all shorelines, the combination of the south-southwest swell, King Tides and the daily high tide will make low-lying coastal areas along south and west shores susceptible to more widespread coastal flooding through the first half of next week.

HFO WATCHES/WARNINGS/ADVISORIES

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