Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
946 FXHW60 PHFO 271353 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 353 AM HST Wed Aug 27 2025 .SYNOPSIS... A low and associated trough north of the islands will remain embedded in a broad, quasi-stationary high pressure ridge, decreasing trade speeds across the state for the next several days, reduced to a hybrid sea breeze and trade wind pattern. Hot and dry conditions will prevail as little to no rainfall will be expected throughout the forecast period. && .DISCUSSION... A low and associated trough remains embedded within a broad, quasi- stationary high pressure ridge north of the islands and will continue to decrease trades to light to locally moderate speeds through the weekend. Hot and dry conditions are progged to prevail during this time as well. Latest satellite imagery depicts stable stratocumulus clouds being observed on windward sides of each island this morning. Furthering the point, temperature inversions from the latest 12z balloon launches at Hilo and Lihue sit in the 6,000 to 7,000 foot range, reassuring shower activity will be limited across the state. Trade speeds reduce even more as the week progresses, resulting in a more hybrid sea breeze and trade wind pattern to develop, likely enhancing leeward and interior region shower activity. However, little to no precipitation is expected from any shower, with precipitation (QPF) values showcased under a hundredth of an inch for most locations through the next couple days. Furthermore, temperatures are progged to be very warm; upwards of 90 degrees in some areas, and is expected to continue through the forecast period. This has posed elevated fire weather concerns (see latest fire weather section). Latest deterministic model guidance of the GFS and ECMWF is in good agreement that the aforementioned low and associated trough will eventually lift northward. This will open the door for the high pressure ridge to rebuild and may result in trades strengthening a bit toward the end of the forecast period. && .AVIATION... A hybrid sea breeze and light to locally moderate trade wind pattern will prevail through the next several days as a low pressure system weakens the high pressure ridge north of the islands. Expect VFR conditions to persist under a typical dry summer weather pattern. No AIRMETs are in effect and none are expected. && .MARINE... A weak trough embedded in the broader ridge north of the islands will keep gentle to locally fresh trades blowing through the weekend. Trade wind speeds might increase back to more typical levels by the middle of next week. A small, long period south swell will trickle through the region maintaining below average surf along south and west facing shores. Another pulse of a small, long period south swell should start building later tonight into Thursday. This swell will to peak by Friday before declining over the weekend, and then returning to background levels early next week. Small choppy surf along east facing shores will hold into Thursday before dropping notch as winds locally and upstream ease through the weekend into early next week. && .FIRE WEATHER... Dry weather conditions will continue through the weekend due to low relative humidity values. However, low wind speeds remain to be the limiting factor for reaching critical fire weather thresholds. By midweek next week, the broad high pressure ridge will rebuild, and may result in winds strengthening a bit. Temperature inversion heights near Maui and the Big Island will range from around 6,000 to 7,000 feet today. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Pierce AVIATION...Pierce MARINE...Bohlin FIRE WEATHER...Pierce