Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
373 FXHW60 PHFO 080125 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 325 PM HST Fri Jun 7 2024 .SYNOPSIS... Light to gentle easterly trade winds will persist into Saturday as a ridge of high pressure meanders north of the the state. Trade winds will briefly shift out of the northeast as a ridge of high pressure moves for west to east north of the state then gradually strengthen. Moderate to locally breezy easterly trade wind conditions are expected by Sunday, and persist into the middle of the new week. Very stable conditions will greatly limit shower activity through the weekend, with a slight increase in windward showers expected Monday and Tuesday. A more typical trade wind pattern should return by the middle of next week. && .DISCUSSION... Surface analysis continues to show a ridge of high pressure located roughly 100 miles north of Kauai which is generating a hybrid sea breeze and gentle easterly trade wind flow across the state. This afternoon visible satellite image shows low level clouds confined along windward slopes and select leeward slopes where sea breezes have become well established. Rainfall totals remain scant across the state based on latest rain gauge observations and radar. Land breeze will develop shortly after sunset which will help clear some clouds, especially for leeward areas through the overnight hours. This dry hybrid trade wind and land/sea breeze pattern is expected to persist into Saturday. The ridge will begin to lift northward and shift eastward Saturday afternoon and evening, shifting winds briefly out of the northeast. Moderate to locally breezy easterly trades are expected by Sunday and persist into the middle of next week as the ridge of high pressure continues to shift northeast of the state. Clouds and showers will return to the more typical windward and mauka areas, however shower activity will remain limited across the entire state over the weekend due to very stable conditions from low inversion heights. The trade wind inversion will begin to lift early next week, which should bring a slight increase in trade wind showers Monday and Tuesday, but will still remain drier than normal for this time of year. A more typical trade wind pattern should return during the middle to latter half of the week with rising inversion heights. && .AVIATION... A ridge of high pressure just north of the state will maintain light trade winds across the region. Trade winds are expected to strengthen on Saturday with locally breezy trades expected by Saturday afternoon. Shower activity will continue to remain limited due to a strong ridge of high pressure aloft. With the strong inversion, ceilings will be quite low with any clouds, which will allow for periods of MVFR conditions. AIRMET Sierra is in effect for tempo mountain obscuration for parts of the Big Island. Ceilings have briefly lifted in select areas, but will likely lower again during the evening hours into tonight. Land breezes should eventually help clear the clouds, but it may take most of the night to fully clear out. && .MARINE... A weak elongated ridge in the northern offshore waters will hold in place over the region. Expect wind speeds to remain below Small Craft Advisory (SCA) threshold through the day Saturday. High pressure will redevelop north of the state over the weekend, allowing moderate trade winds to build back. Models show the potential for SCA conditions across typical windier waters around Maui County and the Big Island by late Saturday into Sunday. The current south-southwest swell will steadily decline through the weekend. That said, observations show this swell is producing surf up to High Surf Advisory (HSA) threshold along south facing shores, prompting continuation of an HSA through tonight. A bigger moderate long period south-southwest swell will build through Saturday, then peak Sunday night into Monday. This swell could generate surf at or above HSA threshold once again at its peak. Yet another long period south swell may generate HSA threshold surf late next week. The current small northwest swell continues to decline. However, a reinforcing pulse from the northwest will continue tonight and give north facing shores a small bump. Wind waves for east facing shores have diminished significantly and will remain small into the weekend. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 AM HST Saturday for all south facing shores. && $$ DISCUSSION...Almanza AVIATION...Kino MARINE...Powell