FXHW60 PHFO 040704 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 904 PM HST Tue Dec 3 2024 .SYNOPSIS... Mostly dry and stable conditions will prevail through Wednesday, with a wetter trend possible Wednesday night through the second half of the week as a front approaches and moves into the area. Light south to southeast winds will gradually increase as the front nears Wednesday night into Thursday, especially over the western end of the state. The front will stall and begin to diminish over or around Oahu Thursday night into Friday. Breezy north-northeast winds will fill in behind it Thursday and Thursday night over the western end of the state, with a brief return of trades Friday. A second front passing north of the area over the weekend could lead to the trades weakening again. && .DISCUSSION... Dry and stable conditions with a deep layer ridge in place over the state will linger into Wednesday, with the land and sea breeze regime continuing. A transition period is anticipated later Wednesday through Thursday as upper heights begin to lower in response to a shortwave trough digging southward into the area. Expect increasing southerly winds and lift ahead of the attendant cold front approaching and moving into the area, that could lead to a few pre-frontal showers as early as Wednesday afternoon for the western end of the state. The better dynamics (40 to 45 kt 0-6 km shear) and upper height falls are expected Wednesday night over and around Kauai, then potentially for Oahu through the day Thursday as the front nears Kauai. Although chances are low, a thunderstorm or two can't be completely ruled out, especially over the adjacent waters of Kauai Wednesday night. A weakening trend is anticipated Thursday night into Friday as the shortwave trough begins to lift northeastward and away from the area. Guidance depicts the frontal boundary stalling around Oahu through this time and slowly diminishing Friday. Expect breezy north to north-northeast winds trailing the front Thursday and Thursday night over the western end of the state, before veering out of the east on Friday. A return of light trades is possible over the weekend as another front passes to the north. && .AVIATION... Light to occasionally variable winds out of the southerly quadrant persist. Sea/land breezes should continue through tomorrow. Any SHRA and low cigs will be brief. While some isol MVFR conds are possible in SHRA, VFR should prevail through the forecast period. A No AIRMETs in effect. AMD NOT SKED in at PHJR and PHMK for equipment issues, with no estimated time for repair. && .MARINE... An E-W oriented surface ridge extending over the islands from the E is supporting gentle winds statewide that are out of the E-SE over Big Island waters, and from the S-SW over Kauai and Oahu waters. Little overall change in the ridge's position is expected through Wednesday. A low passing N of the islands late Wednesday and Thursday will force the ridge eastward, with a tightening low-level gradient supporting fresh to locally strong S to SW winds statewide as an associated front approaches from the NW. Fairly high confidence in the front moving over Kauai on Thursday, then stalling near Oahu from late Thursday into Friday. Winds and/or seas will likely reach Small Craft Advisory (SCA) criteria in at least some of the waters Thursday and Friday. As the front stalls and dissipates, locally fresh post-frontal N winds over Kauai and Oahu will gradually ease and veer to the NE Thursday night into Friday, while light to moderate E winds will prevail over Maui and Big Island waters. Wind speeds will quickly diminish statewide on Saturday, then light ENE trade winds on Sunday are expected to strengthen next week as high pressure builds to the distant NE. Long fetches of near-gale to gale-force winds associated with low pressure systems passing well N of the area will send NW swell of varying sizes and periods toward the islands this week. Most of the swell energy will be in the shorter-period 12-14 second bands, with resultant surf expected to be near or above High Surf Advisory (HSA) levels along exposed N and W facing shores into the weekend. In the short term, significant wave heights at NDBC buoys 51001/51101 NW of Kauai remain elevated at 10 to 12 feet, but the longer period energy present last night and this morning has diminished. A High Surf Advisory (HSA) remains posted for exposed N and W facing shores overnight, and while surf heights will remain elevated on Wednesday, peak heights are likely to diminish below HSA levels. Another NW swell Thursday into Friday will likely produce HSA-level surf, with a smaller NNW pulse possible next weekend. A long-period S swell is currently producing surf near the summertime average along S facing shores, and will gradually decline through Thursday. Another long-period S swell is expected by this weekend, but it will likely be a little smaller than the current swell. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 AM HST Wednesday for Niihau-Kauai Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kauai North-Molokai Windward-Molokai North-Molokai West-Windward Haleakala. && $$ DISCUSSION...Gibbs AVIATION...Walsh MARINE...Birchard