Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
674 FXHW60 PHFO 181914 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 914 AM HST Tue Aug 18 2026 .SYNOPSIS... A more seasonal trade wind pattern has returned to the state with the exit of Hurricane Lala. Expect typical trade wind showers focused along windward and mauka areas through tonight. Trade winds weaken Wednesday into the latter half of the week as a trough passes northeast of the islands. The trough also brings an increase in moisture that will produce an uptick in shower activity through Friday. This weekend, trade winds restrengthen. && .SHORT TERM UPDATE... No changes to the forecast this morning. Trade winds will continue today, weakening for Thursday and Friday. Chances for leeward showers increase during that time. && .PREV DISCUSSION... Issued at 345 AM HST Tue Aug 18 2026 Radar and satellite show isolated showers over the waters upstream of the islands which could produce some light to moderate precipitation for windward and mauka areas this morning. A more seasonal trade wind pattern is expected through tonight, but the trades weaken for Wednesday through the latter half of the week as a trough passes northeast of the islands. The trough brings an increase in moisture that will produce an uptick in shower activity through Friday. With the lighter trades, precipitation chances could spread over leeward areas with the possible development of a sea/land breeze pattern. By this weekend, trades are expected to return, but their strength and direction are more uncertain. These factors will depend on the strength of the subtropical ridge and the evolution of a tropical disturbance in the East Pacific expected to track near the islands by early next week. Most guidance keeps this feature south of the state at this time. && .AVIATION... Issued at 345 AM HST Tue Aug 18 2026 Moderate trades through the forecast period. Low cigs and SHRA along windward and mauka locations. MVFR conds possible in SHRA otherwise VFR prevails. AIRMET Sierra is in effect for mtn obsc along windward portions of all islands. Conds should improve in the mid morning hours. && .MARINE... Issued at 345 AM HST Tue Aug 18 2026 High pressure far northeast of the waters will remain nearly stationary and slowly weaken through Thursday. Wind speeds have eased slightly overnight as the Small Craft Advisory has been cancelled. Trade winds will continue to weaken further to become light and variable for most waters giving way for localized land and sea breezes. By Friday, the high will drift southeast as moderate to locally fresh trade winds will likely build back in. Surf along south facing shores will slowly decline through midweek as offshore buoys south of the islands continue to decline. 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 fade as trades decrease today. North facing shores will remain tiny throughout the week. && .FIRE WEATHER... Issued at 345 AM HST Tue Aug 18 2026 Moderate relatively moist trade winds will prevail through tonight. Winds will weaken Wednesday through Friday with increasing humidity. Trade winds increase over the weekend with possibly some slight drying. The inversion will be around 6000 to 7000 ft today. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...CO DISCUSSION...Quesada AVIATION...Almanza MARINE...Vaughan