textproduct: Honolulu

SYNOPSIS

Breezy trades will continue through at least the middle of the week with showers generally favoring windward and mauka areas, particularly during the overnight through early morning hours each day. Tropical Storm Lowell is currently over 700 miles ESE of the Big Island. Latest forecast track has Lowell passing south of the Big Island late Wednesday into Thursday. Trade winds are expected to become strong and gusty Thursday into Friday as Lowell passes south of the state. Forecast still remains very uncertain for Labor Day weekend, with the potential for Lowell and Karina within the vicinity of the state.

SHORT TERM UPDATE

No major changes to the forecast. Scattered light to moderate showers are tapering off since earlier this morning and becoming more isolated. Windward areas of Kauai and the Big Island received between 0.5 to inch of rainfall over the past 12 hours. Drier air will continue to filter in through the day. Chances of showers will likely increase tonight as a band of low level clouds and showers moves from east to west across the state tonight into early morning Tuesday. Breezy east northeast trade winds will hold as a broad, strong surface high pressure remains far north of the state. Rest of forecast remains on track.

PREV DISCUSSION

Issued at 424 AM HST Mon Aug 31 2026

This morning's radar and satellite imagery shows scattered showers over windward and mauka areas. Rainfall totals overnight have remained on the lighter side, but several gauges around the state did show 0.25 to 0.5 inches of rain during the past 12 hours. While we should see some drier conditions during the day today, another band of moisture could move in tonight, followed by some deeper moisture around Wednesday. So overall, expect some passing showers riding in with the breezy trades over the next few days.

Latest forecast from NHC has Lowell passing little over 300 miles south of the Big Island Wednesday night into Thursday as a cat 2 Hurricane. While probabilities for tropical storm force winds remain low over the state, the tightening of the pressure gradient over the islands will likely produce windy and gusty trade wind weather Thursday into Friday. Winds could reach advisory thresholds with wind gusts over 50 mph possible during this time. As far as rainfall, the bulk of the moisture will likely pass south of the state. Some of the outer rainbands, especially on the tail end of the tropical cyclone could bring in some enhanced trade wind showers around Friday or Saturday.

The forecast spread drastically increases over labor day weekend as an upper level trough/low develops north of the state. Latest 06Z run of the google DeepMind (GDM) model is generally showing a sharper northward turn over the weekend compared to the 00Z run. While confidence has increased on Lowell passing south of the state during the week, the forecast still remains very uncertain over Labor day weekend with several ensemble members of the GDM showing a sharp northward turn. Also during this time, we could see Karina within the vicinity of the islands late this weekend. Please keep an eye out on the NHC page for the official forecast for Lowell and Karina.

AVIATION

Issued at 424 AM HST Mon Aug 31 2026 A strong high pressure system north of the Hawaiian Islands will keep moderate to breezy trade winds in the forecast over the next several days. A unsettled band of clouds and showers continues to drift over the islands this morning, bringing periods of MVFR conditions mainly along the windward mountain areas. These MVFR conditions will ease a few hours after sunrise.

AIRMET Sierra remains in effect for tempo mountain obscurations for north through east sections Kauai, Oahu, Molokai, Maui and the Big Island due to increasing low cloud and shower trends.

AIRMET Tango remains in effect for mod low level turbulence south through west of island mountains. This turbulence AIRMET will likely continue for the foreseeable future.

MARINE

A strong surface high will remain nearly stationary far north of the Hawaiian Islands this week, keeping moderate to locally strong trade winds in place. Tropical Storm Lowell, now in the Central Pacific, is forecast to intensify into a hurricane tonight and will track very close to or move into the southern offshore waters, bringing possible hurricane conditions from Wednesday into Thursday. There is still some uncertainty with the forecast track of Lowell, especially closer to this weekend as the cyclone begins to gain latitude, which will have significant impacts on the wind, wave, and surf forecast for the region. Regardless of Lowell's final path, trade winds will increase this week likely by Wednesday afternoon as a result of the gradient between high pressure to the north, and Lowell to the south. By this weekend, Hurricane Karina, approaching the region from the east, will increasingly be a factor in the forecast of seas and surf as well.

Overlapping small, long- and medium-period south swell energy will keep small surf along south facing shores today. A moderate south swell is expected to arrive Tuesday, then peak on Wednesday, bringing surf heights to just below advisory thresholds. This swell will then gradually decline through the rest of the week, while at the same time, medium period energy from Lowell could start filling in across south and southeast shores. Swell from Lowell could peak this weekend, and its size will be highly dependent on the track and intensity of the storm. Currently the swell from Lowell, based on its current forecast, is estimated to elevate surf but stay below advisory levels.

Trade wind swell energy will keep elevated surf heights along all east facing shores through the coming week. Later in the week, a medium-period east swell arrives from Hurricane Karina that could push east shore surf to advisory thresholds by this weekend into next week.

FIRE WEATHER

Issued at 325 AM HST Mon Aug 31 2026

Breezy trades continue through midweek and then strengthens Thursday through Friday as TC Lowell passes south of the islands. Strong gusty winds with wind gusts over 50 mph will be possible across select areas Thursday into Friday. While fuel conditions do not remain critical at this time due to the abundant rainfall we received over the past several weeks, moderate fire danger will be possible for areas mainly due to the windy conditions. Dewpoints increasing into the upper 60s and low 70s during this time should keep minimum humidities in the 50s for the most part. A few leeward areas could still see humidities down into the mid 40s especially on Thursday as a pocket of dry air moves in. The exact track of TC Lowell remains uncertain and thus potential for meaningful rainfall remains uncertain at this time. The inversion will hover between 5500 ft and 6500 ft the next couple of days.

HFO WATCHES/WARNINGS/ADVISORIES

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