textproduct: Honolulu

SYNOPSIS

Light to moderate east-southeasterly winds will persist this evening, then take on an east northeasterly component by Sunday. Despite the slight variation in wind direction, the light to moderate background flow will bring a combination of limited windward and mauka showers along with isolated sea breeze induced leeward and interior showers. Then easterly trade winds will strengthen to moderate to breezy levels by midweek with an uptick in windward and mauka showers expected.

SHORT TERM UPDATE

Benign weather continues this evening with IR satellite showing isolated low clouds meandering westward towards windward portions of the islands. Over the last 6 hours, there has been no precipitation accumulation reported on any of the smaller islands. However, overcast conditions with embedded showers developed along the southeastern slopes of Mauna Loa on the Big Island this afternoon with up to half an inch of rainfall reported upslope of Pahala.

Cloud coverage over the interiors should further dissipate over the next several hours with the loss of diurnal heating. Hi-res model guidance depicts only spotty showers filling in along windward portions of most islands tonight with dry weather elsewhere. Updated the forecast to decrease cloud cover and shower activity region wide tonight to account for the latest trends.

PREV DISCUSSION

Issued at 328 PM HST Sat Jun 20 2026 A low to the far north and its trailing series of interconnected fronts and troughs draped across the Central Pacific will continue to disrupt the local trade wind flow through Sunday. Light to moderate east-southeast winds will persist through this evening before the approach of the front/trough from the northwest causes the weak background flow to back out of the east-northeast on Sunday. Despite the slight variation in wind direction, this light to moderate background flow will bring a combination of windward and mauka showers along with isolated sea breeze-induced leeward and interior showers through the weekend. However, overall shower activity should remain limited as drier air filters in.

Heading into next week, the subtropical high to the far northeast will gradually regain control, allowing easterly trades to build to moderate to breezy speeds by Wednesday. A weak surface trough, currently seen on visible satellite imagery passing west of 143W near 20N, is projected to track across the island chain late Tuesday into Wednesday on the strengthening trade wind flow. At the same time, model guidance continues to show an upper-level low pinching off from a longwave trough to the far north. This upper low is expected to move toward the state from the northeast, passing westward just north of Kauai Wednesday night through Friday. The combination of low-level troughing, its associated moisture plume, and instability aloft from the upper low will bring an uptick in windward and mauka showers around midweek, as well as with any subsequent batches of moisture rolling through.

AVIATION

Light to moderate easterly trades will persist through Monday, with clouds and a few showers favoring windward and mauka locations overnight through the early morning hours. Expect some cloud buildups over leeward and interior sections through the afternoon hours where localized sea breezes form. No AIRMETs are anticipated through the period, with VFR conditions prevailing.

MARINE

Issued at 328 PM HST Sat Jun 20 2026 Little change to the forecast this afternoon.

A ridge remains northeast of the islands, and a trough to the northwest. The trough is expected to move slowly to the east. This will maintain the light to moderate trade winds through the remainder of the weekend. As the trough moves east and dissipates on Monday, the trade winds will increase. The ridge will strengthen through the week, allowing trade winds to increase.

A small, medium-period south swell will continue to fade, with a new long-period south swell peaking overnight. The result surf along south and west-facing shores should begin to diminish Sunday. Additional medium to long period south and southeast swells are expected through the middle of next week, which will maintain surf heights near seasonal averages.

Tiny surf will prevail along north-facing shores through most of the coming week as limited short-period energy reaches the islands from the north and northwest. As the trade winds increase next week, expect the surf along east facing shores to trend upwards.

HFO WATCHES/WARNINGS/ADVISORIES

None.