Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
663 FXHW60 PHFO 101339 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 339 AM HST Thu Sep 10 2026 .SYNOPSIS... A plume of moisture remains over the eastern end of the state, bringing clouds and showers to the Big Island. Trade winds are starting to filter back into the state, and with the returning trades, expect a return to a more typical trade wind pattern over the next couple of days. && .DISCUSSION... Have made some changes to the grids to nudge the forecast to the latest solution of the GFS. No significant changes to the forecast. Satelite derived precipitable water (PW) continues to show elevated values over the southern end of the state. The overnight Hilo sounding continues to show PW values over 2 inches, which is well above normal. A trough near Oahu this morning continues to move to the west. As the trough moves away, we can expect trade winds to slowly build in from east to west. Moisture will linger, but the focus of showers should return to more typical windward sides of the islands. Expect the trade wind pattern to persist into next week. An upper level low is expected to remain far to the northeast of the state heading into the weekend and then lift northward. Dewpoints remain in the low 70s across the state, and when combined with the light winds, it makes it feel warm and muggy. Models suggest dewpoints will drop back into the upper 60s Friday night, providing some relief from the muggy conditions. && .AVIATION... The trade winds have set up, which combined with moisture being advected in has allowed for showers to continue this morning. Satellite shows a mix of clear skies to mostly cloudy skies because of this, with ceilings generally ranging from VFR to MVFR. The lower ceilings, and at times visibility, are due to the showers and clouds. Expect these conditions to continue over the until around sunrise or so, with drier air gradually working into the region later in the day. AIRMET Sierra remains for the Big Island, Maui, Lanai, and Molokai through at least 10Z. Showers should wrap up between 12-15Z for most sites, with the forecast showing drier trade wind conditions for the late morning and afternoon. For sites PMDY and NSTU, the forecast shows an increase in northeasterly to easterly winds respectively between 18-21Z. Continued the trend based on the GFS, with the stronger winds lingering later in the day for PMDY. Will need to continue to monitor observations and model today, and adjusted accordingly. && .MARINE... Moderate to locally fresh trade winds will gradually return from east to west across the island chain today and then persist into the weekend. The current moderate mid-period south swell will continue to steadily decline over the next few days with below average surf expected by the weekend. Surf along east facing shores will gradually decrease and will remain near seasonal averages through Saturday due to east and northeast swells generated by former tropical cyclones. Surf along north facing shores continues to receive a small bump due to Lowell. This short-period northwest swell will quickly fade, allowing surf to become tiny along north facing shores today as Lowell weakens and tracks westward away from the islands. && .FIRE WEATHER... Fire weather risk will remain low the next several days due light winds and lingering moisture. Expect a slight chance of thunderstorms over the Big Island this afternoon. Temperature inversion heights are expected to remain elevated or weak. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...M Ballard AVIATION...KR MARINE...Walsh