Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
949 FXHW60 PHFO 041310 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 310 AM HST Sat Oct 4 2025 .SYNOPSIS... Light to locally moderate winds prevail through much of the weekend. A broad surface low develops northeast of the state early next week and will propagate westward across the island chain, resulting in winds tapering off into a land and sea breeze regime, persisting through the latter half of the week. As the aforementioned low exits the vicinity, trades are expected to return through the remainder of the outlook period. && .DISCUSSION... A slow-moving frontal passage northwest of the Hawaiian Islands will continue to trek southeastward before stalling and fizzling out by midday today. Latest satellite imagery depicts scattered plume showers sporadically around the islands, predominately impacting the smaller islands, as well as cloud coverage build up within the interior of some islands. These showers are expected to taper off later this morning. Latest 12z soundings depicts the temperature inversion heights across the state range from 6500 to 7500 feet today, with precipitable water values near 1.31 inches near Hilo. Light to locally moderate winds prevail for much of the area throughout the day and carry through much of the weekend. Latest model guidance of the GFS and ECMWF continue to depict a broad surface trough developing just northeast of the state around Monday, slowly propagating westward across the island chain. As a result, winds will taper off into a more light and variable pattern. In the absence of local scale winds, island heating will develop sea breezes each day, and overnight cooling will drive downsloping land breezes each night. During the day, sea breezes will enhance leeward and interior region shower activity, while land breezes overnight will clear the night skies, limiting showers. This land and sea regime is progged to continue through latter half of the week until the aforementioned surface low exits the vicinity of the islands late Friday, allowing trades to return through the remainder of the outlook period. && .AVIATION... Moderate easterly trade winds are expected through the weekend with clouds and showers focused mainly over windward and mauka areas. Trade wind flow may allow for sea breezes to develop across leeward areas each afternoon, bringing clouds and isolated showers to those areas. Localized MVFR possible within passing showers, but most sites will remain VFR. No AIRMETs are currently in effect. && .MARINE... A cold front to the northwest and a trough to the northeast are the driving forces to maintaining a light to moderate east- southeast flow over the area. With both of these features expected to weaken today, expect moderate east-northeast trades to filter back in over the area, and linger through thru the remainder of the weekend. A trough may develop northeast of the state early next week, once again weakening winds to light and variable. A moderate, medium period north northwest (330 deg) swell generated from the current low located far north-northwest of the islands is expected to fill in today, 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, long period southwest (210 deg) swell will continue to slowly decline into early next week. A small, long period southwest swell may arrive late Sunday and build into early next week before subsiding. Another small long period southwest (200 deg) swell is possible by the later half of next week. Surf along east-facing shores will remain below average into early next week with the a slight boost Saturday into Sunday as moderate to fresh trades briefly return. && .FIRE WEATHER... Wind speeds and humidity will remain below critical fire weather thresholds for the next several days. Temperature inversion heights across the state will range from 6500 to 7500 feet today. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Pierce AVIATION...Shigesato MARINE...M Ballard FIRE WEATHER...Pierce