Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
765 FXHW60 PHFO 021327 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 327 AM HST Thu Oct 2 2025 .SYNOPSIS... Gentle to moderate east southeast winds will continue through Friday night in response to an approaching cold front in the North Central Pacific, allowing localized daytime sea breezes and overnight land breezes through Friday night. Moderate trades may build back this weekend into early next week as a new high builds north of the state. && .DISCUSSION... Gentle to moderate east southeast winds will continue through Friday night in response to an approaching cold front in the North Central Pacific. 12Z soundings show conditions aloft remain stable with a 7 to 8 kft inversion across the state. Infrared satellite and radar show low clouds and a few showers tracking in a southeast to northwest direction this morning occasionally impacting windward slopes. Most showers are passing north and south of the islands likely from downstream partial blockage from the Big Island. Showers will taper off through the late morning, while mostly sunny to partly cloudy skies prevail for leeward locations. The light wind flow and Big Island blockage will allow localized sea breezes and interior cloud build ups and showers over the islands this afternoon. Land breezes will clear out the islands tonight, followed by a diurnal repeat Friday and Friday night. Downstream convergence along the leeward sides of island mountains could produce plumes of clouds and showers that extend west to northwest from each island, and could anchor showers over windward and southeast sides of the smaller islands at times overriding the land breeze suppression. Guidance indicates that easterly trades will build back into the region this weekend and early next week as a new high develops and strengthens far north of the state. However, global models differ significantly regarding the development of a trough northeast of the islands by the middle of next week. This could cause significant differences in the wind and shower regimes near the end of the seven day forecast. && .AVIATION... Moderate trades will persist and gradually veer ESE tomorrow into Friday. Low clouds and showers will mainly focus over windward and mountain areas, particularly overnight into the early morning hours. The slightly veered trade wind flow may allow for sea breezes to develop across leeward areas each afternoon, bringing clouds and isolated showers to those areas. MVFR conditions will be possible in any showers through the period. Otherwise, VFR will prevail. No AIRMETs are in effect. AIRMET Sierra may be needed across some windward areas tonight if shower coverage becomes sufficient. Kilauea eruption episode 34 ended this morning at 7:03 AM HST. The potential for ash to impact aviation has diminished, so VA SIGMET Whiskey has been cancelled. && .MARINE... Surface high pressure northeast of the waters will continue to drift east through the end of the week as a trough passes far north of the waters. The current gentle to locally fresh trade winds will veer east southeast and trend lighter through Saturday giving way to localized land and seabreezes over leeward waters. High pressure will build in from the northwest allowing moderate to locally fresh trade winds to return this weekend and hold through the forecast period. A small medium to long period northwest (300 deg) swell from Tropical cyclone Neoguri has begun to fill in early this morning, will peak later today before declining through Friday. A moderate, medium period north northwest (330 deg) swell generated from the current low tracking across the northwest Pacific is expected to fill in on Saturday, peak Sunday just below High Surf Advisory (HSA) criteria for north facing shores, and slowly fade into early next week. Another small medium to long period swell from the northwest (320 deg) is expected to fill in Monday, peak Tuesday and decline through the middle of next week. The current small, medium period southwest (210 deg) swell has filled in overnight and will peak today, before fading Friday. Another small long period southwest (210 deg) swell is expected to rise late Friday through Saturday before declining into early next week. Surf along east- facing shores will remain below average into early next week. && .FIRE WEATHER... Wind speeds will remain below critical fire weather thresholds for the next seven days. Temperature inversion heights across the state will range from 7,000 to 8,500 feet. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION/FIRE WEATHER...Foster AVIATION...Ahue MARINE...Shigesato