Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
125 FXHW60 PHFO 300154 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 354 PM HST Mon Sep 29 2025 .SYNOPSIS... Dry weather until an band of moisture moves in with the trade wind flow. Showers may increase Wednesday and Wednesday night, followed by a shift to southeasterly winds. && .DISCUSSION... Trade wind speeds will trend lighter to moderate levels across the islands tonight into Tuesday as the driving subtropical high weakens. Clouds and showers will be limited through Tuesday and focus windward, and over the Kona slopes of the Big Island during the afternoon. A strong inversion around 7 kft and relative low precipitable water values will limit any significant rainfall. A band of clouds and showers, parhaps from an old, dissipated front, will move in with the flow early Wednesday morning lingering into Wednesday night. Showers will focus windward, and likely carry over to leeward sides of the smaller islands at times Wednesday night. Trades will maintain moderate speeds through Thursday, then weaken a bit more and veer southeasterly ahead of an intruding low pressure system in the North Central Pacific. The southeast flow will continue through Saturday, and localized land and sea breezes may set up across much of the state. Expect, warm and muggy conditions. This feature weakens Sunday with trade winds coming back. && .AVIATION... Moderate to locally breezy trades will continue to favor limited clouds and showers, mainly over windward and mauka areas. Localized MVFR possible within passing showers, but most sites will remain VFR. AIRMET Sierra in effect for mountain obscuration due to low clouds and showers over Kauai, Oahu, Molokai, Lanai, Maui, and the Big Island. Conditions expected to improve later this morning. && .MARINE... Moderate to locally fresh easterly trade winds will persist through much of the week. The Small Craft Advisory (SCA) for windier waters and channels around Maui and the Big Island has been cancelled with this afternoon`s forecast package as winds trend slightly weaker. A small medium period north swell filled in earlier today, bringing small surf to north facing shores. This swell will gradually fade heading into tomorrow and a series of small medium period swells from the north and northwest will trickle in through the rest of the week. A moderate medium period northwest (330 degrees) swell is expected to arrive on Sunday, building surf heights along north and west facing shores late this weekend into early next week. Surf along south facing shores will continue to slowly fade tonight from a small medium period south swell. A series of small medium period south swells will keep surf along south facing shores from going flat through the week. Surf along east facing shores will remain on the small side in moderate trade wind flow, despite some small medium period swell moving into the region over the next couple of days from former tropical cyclone Narda. && .FIRE WEATHER... Winds expected to stay below fire weather threshold through the week. Humidity levels will maintain and the current stable 7 kft inversion will stay in place much of the week. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST this evening for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION/FIRE WEATHER...Foster AVIATION...TS MARINE...Farris