Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
619 FXHW60 PHFO 110136 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 336 PM HST Mon Jun 10 2024 .SYNOPSIS... Moderate to breezy trade winds will persist through the week as broad high pressure remains north of the state. Stable conditions will focus limited showers over windward areas, and leeward areas will be rather dry, though leeward Big Island will experience clouds and showers each afternoon and evening. && .DISCUSSION... A breezy and stable trade wind flow is producing a somewhat dry June weather pattern this afternoon. A 1030 mb surface high centered about 1,100 miles northwest of Kauai is driving the trades, and a mid-level ridge is maintaining an inversion based between 5,000 and 7,000 ft. Shallow moisture in the trade wind flow has produced scant rainfall of less than a tenth of an inch across windward Big Island and Maui during the day, as well as a few showers over the South Kona slopes this afternoon. Elsewhere, while little precipitation has been measured. Little change is expected through the week. The surface high will move eastward during the next several days and settle far northeast of the state by Saturday. A surface ridge trailing the high will remain north of the islands, but it may be weakened enough for us to experience a subtle decrease in trade winds for Friday into the weekend. Persistent mid-level ridging over the state will maintain a stable pattern of mainly windward rainfall through at least Friday. Aside from afternoon showers on the Kona slopes of the Big Island, somewhat dry weather will persist for leeward areas. Random pockets of shallow moisture moving along the trade wind flow will periodically boost windward rainfall, and one such area is expected Tuesday night and Wednesday. A weak disturbance aloft could drive an increase in showers during the weekend. && .AVIATION... Breezy and dry trades will hold steady, delivering clouds and limited showers to windward and mauka zones through the period. MVFR will be possible on an isolated basis, but otherwise VFR prevails. && .MARINE... Fresh to locally strong easterly trades will continue through much of the week as a surface high strengthens to the north. Guidance suggests winds may relax slightly over the weekend as the high shifts far northeast of the state and weakens. A Small Craft Advisory has been extended for the typically windy areas around Maui County and the Big Island through Wednesday, but will likely persist through much of the forecast period. Surf along south-facing shores is starting to trend down as a small long period swell moves through. Surf along south facing shores will hold at advisory levels through tonight, then continue to trend down Tuesday through midweek, with a mix of the fading south-southwest swell and a small, medium-period southeast swell. A similar long-period south swell is expected to arrive Thursday night into Friday and peak late Friday into Saturday. This swell could raise surf back up to advisory levels. Tiny surf along north-facing shores will continue through the first half of the week as small north to north-northwest pulses move through. The next north pulse should fill in tonight, with a small north-northwest swell arriving Tuesday into midweek. A return to summertime/flat conditions is likely later this week through next weekend. Small choppy surf along east-facing shores will persist the next couple of days with an upward trend later this week as the trades become more established locally and upstream across the eastern Pacific. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 AM HST Tuesday for Niihau-Kauai Leeward-Waianae Coast-Kahoolawe-Maui Leeward West-Kona-Kauai South-East Honolulu-Honolulu Metro-Ewa Plain-Molokai West- Molokai Leeward South-Lanai Leeward-Lanai South-Maui Central Valley South-South Maui/Upcountry-South Haleakala-Big Island South-Big Island Southeast. Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Wroe AVIATION...JVC MARINE...Almanza