Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
262 FXHW60 PHFO 191926 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 926 AM HST Wed Aug 19 2026 .SYNOPSIS... Trade winds weaken today 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. A new potential tropical system is forming southeast of the state. Forecasts from the National Hurricane Center will likely begin Thursday morning. && .SHORT TERM UPDATE... All eyes are on a potential tropical storm currently developing in the vicinity of 10N 140W. NHC will likely begin forecasts on this later today or early Thursday morning. At this time, it is expected to move toward the state Saturday through Sunday. It is too early to forecast an exact path, but ensembles show a general consensus toward a track similar to Lala, or perhaps a bit farther south. Again, it is too early to have an exact path, and this cannot be overstated. Otherwise, isolated to scattered mainly windward and mauka trade wind showers are expected today, increasing overnight as usual. No changes will be made this morning as the current forecast is on track. && .PREV DISCUSSION... Issued at 327 AM HST Wed Aug 19 2026 Trades weaken today through Friday as a trough approaches and passes just north of the state Thursday night into Friday. The trough will bring additional moisture across the islands, but with lighter trades will increase precipitation chances for leeward areas during the afternoons with the development of a sea/land breeze pattern. The winds are expected to strengthen and shift easterly late Friday into Saturday, which will focus clouds and showers windward and mauka. For Sunday and Monday, tropical moisture is expected to be in the vicinity of the state due to the potential development of a tropical system. Most guidance keeps the track of the potential tropical system south of the islands. While there remains uncertainty in the forecast since the system has yet to develop, precipitation chances have been increased for early next week. Please continue to monitor the forecast as it is subject to change as we get closer to the weekend and details surrounding the forecast become clearer. && .AVIATION... Issued at 327 AM HST Wed Aug 19 2026 Moderate trades expected through tomorrow. Some windward and mauka SHRA possible with isol MVFR conds. VFR conditions should prevail. No AIRMETs are currently in effect. && .MARINE... High pressure far northeast of the waters will remain nearly stationary and slowly weaken for the next couple of days. As a trough to the east of the islands passes to the northeast, moderate trades will become light and variable for most waters by Thursday, allowing daytime sea breezes and overnight land breezes to become established. By late Friday, moderate to locally fresh trades will begin to build back into the region as the high drifts southward closer to the island chain and an area being watched closely for potential tropical development nears the state from the southeast. Surf along south facing shores will remain near or slightly below average through midweek as the current south swells fade. A long period south swell generated from gales just south and east of New Zealand will begin arriving late Thursday into Friday. Surf along east facing shores will continue to fade as background flow becomes weaker. North facing shores will remain tiny throughout the week. && .FIRE WEATHER... Issued at 327 AM HST Wed Aug 19 2026 Trade winds will weaken today through Friday, increasing chances of showers for the leeward side of the islands. Trade winds increase over the weekend with showers switching to windward. The inversion is 6000 to 7000 ft. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Foster AVIATION...Walsh MARINE...Farris