Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
972 FXHW60 PHFO 121314 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 314 AM HST Sun Oct 12 2025 .SYNOPSIS... An upper-level low approximately 800 miles north of the islands will dig south through midweek. This will increase instability and introduce a chance for heavier showers and a few thunderstorms. East to southeast surface winds continue, becoming stronger from Wednesday into next weekend. && .DISCUSSION... Looking at radar at 3AM, a few showers are moving across the region. Nighttime Microphysics satellite imagery indicates some high clouds streaming in the from southwest. A few low-level clouds are isolated in nature and most spots are seeing relatively clear skies. A strong upper-level low digging south toward the state will help determine our weather for the coming week. An increase in low- level mositure and instability is expected as the low gets closer. As such heavier showers and a few thunderstorms are possible Tuesday afternoon through Thursday. Conditions will remain favorable for thunderstorms through at least Friday. Models are in some disagreement as far as timing and placement of this low. This is causing some uncertainty in exactly where and when we could see heavier showers and thunderstorms. However confidence is increasing that we will most likely see some heavy showers and thunderstorms over at least the western side of the state. Details will continue to be refined in the coming forecasts. && .AVIATION... Light E-ESE winds have resulted in land breezes keeping skies relatively clear. Expect winds to remain light today with sea breezes developing over leeward and interior locations. A few SHRA and some low cigs with isol MVFR conds will be possible but otherwise VFR will prevail. No AIRMETs in effect. && .MARINE... Broad troughing north of the islands will keep the local pressure gradient somewhat weak, maintaining mainly gentle to moderate trade winds over coastal waters into Tuesday. The trough will gradually fill in late Tuesday and Wednesday, and building surface high pressure north of 30N will drive strengthening trade winds. Small Craft Advisory conditions may develop over the typically windy waters around the Big Island and Maui as early as Wednesday night and likely by Thursday. As trades strengthen, a disturbance aloft will drift southward over the islands and bring instability. Small to moderate northwest swell this morning will give way to a long period forerunners of a new northwest (320 deg) swell building late today and tonight. Surf should peak at High Surf Advisory levels Monday and Tuesday for most north and west shores from Kauai to Maui. Surf will gradually decline Thursday and Friday, with some small northwest swell lingering into next weekend. Tiny background south swell will prevail through the week. A slight increase to near seasonal normal as medium-period easterly swell from a distant tropical cyclone moves across the area today. East shore surf will be small Tuesday, then increase and become rough during the second part of the week as trade winds build over and upwind of the islands. Water levels during morning high tides will continue to gradually lower during the next couple of days. Water levels peaked just below the flooding level at most stations yesterday with conditions expected to be borderline at high tide morning. && .FIRE WEATHER... Light winds and isolated showers will help maintain fire weather below critical thresholds for the next several days. Inversion heights will range from 6,000 to 7,000 feet. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Walsh AVIATION...Walsh MARINE...Foster FIRE WEATHER...Walsh