FXHW60 PHFO 270638 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 838 PM HST Thu Sep 26 2024 .SYNOPSIS... Moderate trade winds will prevail through much of next week, with slightly decreasing wind speeds from Sunday onward. Typical trade wind showers will favor windward and mountain zones in the overnight to early morning hours for the next seven days. && .DISCUSSION... The satellite imagery this evening shows bands of clouds, associated with a weak disturbance aloft, riding into the windward and mountain slopes of each island on the trade winds. These clouds will produce brief passing showers mainly during the overnight to early morning hours. A weak high pressure system north of the Hawaiian Islands will continue to produce moderate trade winds into much of next week. The forecast changes over the next seven days will be subtle with a slight decrease in trade wind strength from Sunday onward as the ridge to the north breaks down due to the passage of a cold frontal system. The shower forecast will also see only minor day to day changes with a weak disturbance moving over the island chain in the short term forecast. Expect a brief increase in shower trends from Friday night to early Saturday, then drier conditions are expected to return for the rest of the weekend. && .AVIATION... Moderate to locally breezy trades will continue for the next several days. Low cigs and SHRA will impact windward and mauka areas. Brief MVFR conds can be expected in heavier SHRA but VFR should prevail. NO AIRMETs currently in effect however with increased SHRA overnight AIRMET Sierra for mtn obsc is possible along windward locations. && .MARINE... A weak high pressure system north of the state will maintain gentle to fresh trade winds through the rest of the week. The latest forecast wind guidance keeps wind speeds just below Small Craft Advisory thresholds in the channels near Maui and the Big Island. This weekend a cold frontal system will move into the Central Pacific basin, weakening the ridge north of the state. Trade wind speeds will ease slightly from Sunday onward. The current moderate northwest swell (320 to 330 degrees) will continue to gradually decline through Friday. However, a new small, medium period north-northwest swell (330 to 340 degrees) will build in Friday night, providing a small, short lived boost to surf along north and select west facing shores this weekend. A series of overlapping south and southwest swells will keep south shore surf slightly elevated into early next week. Although the current long period southwest swell and an overlapping tiny short period southwest swell will fade through tonight, another tiny long period southwest (220 degrees) swell will build in by Friday. The next small, long period south-southwest swell (200 degrees) is expected to fill in Monday and peak Tuesday into Wednesday. East facing shores will remain small through early next week due to the lack of strong trades both locally and upstream. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Bohlin AVIATION...Walsh MARINE...Bohlin