textproduct: Honolulu

SYNOPSIS

Tropical Storm Lala is continuing to move west of the state. Some lingering scattered showers will continue through the day. Trade wind pattern returns Tuesday with windward and mauka showers. Later this week winds may veer slightly southeast.

SHORT TERM UPDATE

Main update to the forecast this morning was to increase the rainfall forecast mainly across the windward and mauka parts of the islands through this evening. Radar and satellite show light scattered showers moving towards the windward sides of the islands this morning. Observations over the past 3 hours show up to 0.35 inches, locally up to 0.55 inches of additional rain over the Ko'olaus, 0.25 inches of additional rain has fallen on the windward side of the Big Island with up to 0.20 inches of additional rain on the windward side of Maui and Kauai. Lingering moisture in the air from Tropical Storm Lala will create continued chances for additional light showers through this evening. Shower activity will dissipate into Tuesday as moisture decreases and trade wind weather returns.

PREV DISCUSSION

Issued at 404 AM HST Mon Aug 17 2026

Radar and satellite show some showers along windward Oahu and some leftover bands of rain from Tropical Storm Lala moving over Kauai and Niihau. Showers will continue to dissipate as trade wind weather returns.

Tropical Storm Lala continues to move away to the west, well southwest of Kauai. Tropical storm warnings are cancelled. The Flash Flood watch has also be cancelled. With the departure of Lala winds will ease into the moderate category. Inversion depth and PWATs will remain a little higher than normal through the upcoming week, leading to relatively wet trades. Showers can be expected over windward and mauka locations with some isolated spillover into leeward areas. These trades will veer to the east- southeast Thursday night, and remain that way through next weekend.

AVIATION

Conditions have improved since yesterday. Lingering MVFR ceilings and showers will continue across windward areas of Kauai and the Big Island. A more typical trade-wind pattern over Oahu and Maui will focus brief MVFR ceilings and showers over windward and mountain areas. Overall, VFR conditions should prevail.

AIRMET Sierra for mountain obscuration will remain in effect for windward Kauai and the Big Island.

MARINE

The center of Tropical Storm Lala has just exited the western edge of the offshore waters this morning as it continues to move west. Fresh to locally strong easterly trade winds will gradually build through the day from the east to west. A Small Craft Advisory (SCA) remains in effect for the windier waters and channels around Maui County and the Big Island through tonight. By midweek, trade winds will ease through the forecast period to gentle to fresh speeds across all coastal waters.

Surf along south facing shores will remain elevated today from a moderate medium to long period swell that has filled in overnight. Went ahead and bumped up the south shore surf slightly for this morning based on the latest buoy observations. Surf will likely peak today before slowly declining through midweek. Another long period south swell generated from gales just south and east of New Zealand will begin arriving late this week.

Surf along east facing shores will continue to decline today as Lala progresses further west of the state. East facing shores will remain small to moderate through the forecast period. North facing shores will remain tiny with only wind wave-driven chop in tandem with the declining east swell wrap. West facing shores will also remain tiny to small with some south swell wrap.

FIRE WEATHER

Issued at 924 AM HST Mon Aug 17 2026

Moderate relatively moist trade winds will prevail through at least Thursday removing fire weather concerns in the short-term. There is no temperature inversion.

HFO WATCHES/WARNINGS/ADVISORIES

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