textproduct: Honolulu

SYNOPSIS

Trade winds will ease slightly on Monday as Tropical Storm Moke passes several hundred miles south of the islands. Moisture along the northern periphery of Moke will bring wet conditions and a risk of flash flooding on the Big Island, while less rainfall is expected to impact windward sections from Maui to Kauai over the next couple of days. Trade winds will drop to moderate strength on Tuesday as Moke moves westward away from the area, with drier trade wind weather returning for the remainder of the week.

SHORT TERM UPDATE

Scattered showers continue across the Big Island and Maui. Windward and mauka showers will continue over the rest of the main Hawaiian Islands overnight. The Wind Advisory that was in effect for parts of Maui County and the Big Island has been cancelled as winds have dropped below advisory criteria. The Flood Watch remains in effect over the Big Island through tomorrow afternoon. Outside of slight adjustments to PoPs and wind the previous forecast is on track.

PREV DISCUSSION

Issued at 347 PM HST Sun Aug 23 2026

Locally strong and gusty trades winds continue statewide, and wet conditions prevail on windward Big Island as moisture along the northern periphery of Tropical Storm Moke brushes the southern end of the island chain. The exposed low level center marking the center of Moke is currently centered over 300 miles south- southwest of Kailua-Kona, while deep moisture being sheared to the north of the system is largely skirting just south of Big Island. This has kept rainfall on windward Big Island at light to moderate intensity today, limiting rainfall to less than one inch during the past 12 hours and less than a half of an inch in Kau and much of windward Maui. While the wind field surrounding Moke is well south of the islands, the tropical storm is helping to produce a rather tight pressure gradient over the state. The resulting breezy trades are enhanced over and just south of terrain, especially on portions of Big Island and Maui County where gusts of around 50 mph are supporting a Wind Advisory.

A flood threat will continue for the Big Island through Monday. As Moke continues to move westward, low- to mid- level flow on the Big Island will shift out of the east to east- southeast, which could optimize orographic lift and increase rainfall on windward and southeast slopes. The guidance continues to show large variation in potential total precipitation, meaning that confidence is lower than normal, but the main window for flooding will be through early Monday morning on windward areas, with a chance for spotty afternoon showers to produce localized flooding across the Kona Districts. A Flood Watch is posted for Big Island through Monday afternoon. Elsewhere in the state, expect somewhat wet conditions windward, with passing showers leeward on gusty trades. Later tonight and Monday, trades will gradually lower as departing Moke allows the local pressure gradient to slowly relax.

Drier conditions will develop on Tuesday as trades fall to moderate strength. Expect much of the coming week to feature typical trade wind weather, with showers favoring windward slopes.

AVIATION

Tropical Storm Moke was centered nearly 300 hundred miles south of the Big Island and continued on its westward track. Rain bands from the tropical storm will impact windward Big Island through the overnight into early Monday, which will bring MVFR and periods of IFR conditions to the area.

Trade winds are expected to be moderate to locally strong statewide. Outside of windward Big Island, showers embedded within the trade wind flow will primarily impact windward and mountain areas, bringing periods of MVFR conditions. Otherwise, VFR will prevail.

AIRMET Tango is in effect for low level turbulence downwind of terrain due to the strengthened trade winds. AIRMET Sierra is in effect for mountain obscurations over windward portion of the islands. An AIRMET for IFR conditions over portions of windward Big Island is also a possibility tonight.

TC SIGMET series XRAY covers Tropical Storm Moke and its convection.

MARINE

Locally strong trades persist through tonight as Tropical Depression Moke passes south of the island chain and broad high pressure remains north of the state. Convection associated with this system will remain over the southern portion of the offshore waters as it tracks west, exiting the region by Monday. The Small Craft Advisory remains in effect through tonight but will likely be extended for the typical windy waters of Maui County and the Big Island. Locally strong trades return Monday night into Tuesday.

Elevated winds and short period fresh swell generated by TD Moke have peaked over the eastern half of the state. Surf along E and ESE facing shores will trend down through tonight as Moke advances westward. Conditions remain choppy, however, as trades persist.

Surf along S shores remains below summer norms but still slightly elevated due a lingering small, long period SSW swell. A 3-4 foot, medium to long period S swell will arrive Monday into Tuesday in maintenance of near-normal summertime surf. A similarly sized long period S swell is then poised to arrive midweek boosting surf toward the advisory threshold.

A small, medium to long period WNW swell originating from Hurricane Lala will fade during the next 24 to 36 hours.

FIRE WEATHER

Locally strong and gusty trades will ease later tonight and Monday, while humidity remains higher than normal due to moisture on the northern periphery of Tropical Storm Moke brushing the state. Heavy rain is expected on windward and southeast slopes of the Big Island, while lower rainfall totals are expected over other windward areas. The inversion will be weak to non-existent into Monday. A typical summertime trade wind pattern will return by Tuesday.

HFO WATCHES/WARNINGS/ADVISORIES

Flood Watch through Monday afternoon for Big Island East-Big Island Interior-Big Island North-Big Island South-Big Island Southeast-Big Island Summits-Kohala-Kona.

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