Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
995 FXHW60 PHFO 260642 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 842 PM HST Wed Sep 25 2024 .SYNOPSIS... High pressure north of the islands will keep moderate trades blowing through Saturday, with perhaps a slight easing Sunday through early next week. Rather dry trade wind weather will prevail through the weekend, with showers favoring windward slopes and coasts. A slight increase in trade wind showers will be possible next week as the remnant moisture from some old fronts move into the region from the east. && .DISCUSSION... Currently at the surface, a west to east oriented ridge of high pressure is located around 700 miles north of Honolulu, and is driving moderate trade winds across the island chain this evening. Cira ProxyVis satellite imagery shows mostly cloudy conditions in windward areas, with partly cloudy skies in most leeward locales. Radar imagery shows scattered showers moving into windward slopes and coasts, with a decaying shower occasionally spilling over into leeward areas. Main short term focus revolves around trade wind trends and rain chances. The ridge of high pressure north of the islands will remain nearly stationary through Friday night, maintaining moderate trade winds across the island chain. The trades will likely be light enough that some localized sea breezes develop each afternoon in the most sheltered leeward locations. The trades appear to ease slightly this weekend through early next week, as a series of fronts approach and stall out to the distant northwest. As for the remaining weather details, the combination of mid-level ridging over the islands and deep tropical moisture remaining displaced to the south, will keep rather dry trade wind weather in place through at least the weekend. Scattered showers will favor windward and mauka areas, with a decaying shower reaching leeward areas at times. Some deeper moisture associated with the remnants of some old fronts may get caught up in the trades next week, bringing an increase in trade wind shower coverage. && .AVIATION... Moderate to locally breezy trades will continue for the next several days. SHRA and low cigs should mainly be focused on windward and mauka locations. Brief MVFR conds are possible in SHRA, otherwise VFR should prevail. No AIRMETs in effect. && .MARINE... A weak high north of the state is still managing to produce moderate to locally strong trade winds. A Small Craft Advisory (SCA) for the typical windy waters around Maui County and the Big Island remains in effect through Thursday morning due to lingering borderline conditions. A distant front approaching from the far northwest will gradually weaken this high and shift it northeast of the state this weekend. In response trades will gradually weaken into the gentle to locally fresh range by Sunday and hold at these levels through early next week. The moderate, long period northwest swell (320 to 330 degrees) will continue to gradually decline overnight through Friday. A small, medium to short period north- northwest swell (340 to 360 degrees) will build in Friday providing a small, short lived boost to north and select west facing shores surf this weekend. Multiple small, south and southwest swells (220 to 200 degrees)) are expected now into early next week. The current small, long period southwest swell will continue to decline through Thursday along with an overlapping tiny, short period southwest swell. A couple of tiny, long period southwest swells are then expected Friday through the weekend keeping small surf along south facing shores. 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 into early next due to the lack of strong trades locally and upstream. Easterly surf may gradually build by mid week next week as strong trades return. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Thursday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Jelsema AVIATION...Walsh MARINE...Almanza