000 FXHW60 PHFO 280135 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 335 PM HST Wed Oct 27 2021 .SYNOPSIS... A ridge of high pressure is located just north of the area resulting in mostly light to locally moderate trade winds. Local land and sea breezes can be expected over the next few days under this regime. Showers will tend to favor windward and mauka areas with some afternoon clouds and showers over interior areas. The ridge will move down over the area later in the weekend and on into early next week resulting in light and variable winds and rather dry weather conditions. && .DISCUSSION... Areas of high pressure are centered far northeast and far north northwest of the state. Meanwhile a frontal boundary lies between the 2 highs with its leading edge located about 360 miles north of Kauai. This weather pattern is resulting in mostly light to locally moderate trade winds across the area. The winds are light enough to allow for local land and sea breezes to occur across some locations. The airmass is rather dry and stable with just a few light showers seen falling primarily over windward and mauka areas. Guidance is in good agreement with keeping this light wind pattern in place on into Friday. Meanwhile, the front is forecast to stall and dissipate a couple of hundred miles north of Kauai Thursday and Friday. Satellite imagery along with CIMSS derived precipitable water imagery shows an east to west oriented band of moisture just north of the state. Guidance indicates that this moisture may sag down over Kauai later tonight and linger on through Thursday night. The southern edge of this band may make it as far south of Oahu but should not have much impact on the rest of the state. Thus we expect some increase in shower activity over windward and mauka areas and with the light wind. There may be some increase in interior and leeward showers especially during the afternoon hours on Thursday. As we head into the weekend, another frontal boundary will be approaching the area from the northwest. Winds will remain light but become more variable in direction. Land and sea breezes will continue to dominate across most areas. The airmass will be on the drier side so showers will be rather limited with the greatest chances during the afternoon hours due to daytime heating and sea breeze convergence. This weather pattern is expected to remain in place on into early next week. && .AVIATION... A gentle to moderate trade wind regime will continue over the next several days. Clouds and a few showers associated with a weak surface trough will drift southward near Kauai and Oahu tonight, and may bring brief mountain obscurations, MVFR visibility and ceiling in the vicinity of showers through tonight. AIRMET Sierra is posted for tempo mountain obscurations over the windward side of Oahu into this evening. && .MARINE... A high passing to the north will support gentle to moderate trades as it moves steadily east. As the high moves further away Friday, and low pressure passes north of the islands, light and variable winds will prevail through the weekend and early next week. A front will approach the islands from the north Sunday, and may stall near the islands Monday. A north swell will gradually be on the decline today, as a new north- northwest swell coming tonight looks to maintain surf heights through tomorrow before declining Friday into the weekend. A new, large north-northwest swell will be arriving late Saturday into Sunday, bringing high surf to north and west facing shores. High surf will be on the decline on Monday but a reinforcement swell will likely bring more high surf for north and west facing shores Tuesday. A small south swell is expected over the next couple of days. East shores will remain small over the forecast period, however the north swell may wrap into exposed locations along select east facing shores. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Burke AVIATION...Foster MARINE...Shigesato/Birchard