Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
706 FXHW60 PHFO 071906 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 906 AM HST Mon Apr 7 2025 .SYNOPSIS... Breezy trade winds will persist through the week, with clouds and showers favoring windward and mauka areas overnight and during the morning hours. A band of moisture associated with a remnant front drifting south over the islands, along with a developing upper-level trough later in the week, may lead to periods of enhanced windward showers from tonight through the second half of the week. && .DISCUSSION... Short-term guidance remains in good agreement, indicating a weakness forming in the surface ridge today through Tuesday night as a cold front passes well north of the islands. This will lead to the pressure gradient relaxing slightly, causing breezy trade winds to ease into the moderate to locally breezy range tonight through Tuesday. While showers will remain limited today, coverage may increase from tonight through Tuesday night as a shallow band of moisture moves into the area. Given the shallow nature of this boundary, rainfall accumulations should be light, with little reaching leeward areas, especially as trades weaken. By Wednesday and through the latter half of the week, guidance shows the surface ridge re-strengthening as a 1035 mb high builds to the north. This will lead to the return of breezy northeast trade winds across most of the state, particularly over the western end, where the remnant boundary may continue to linger. Windward areas can expect periodic showers, driven by this lingering shallow moisture and an evolving broad upper trough over the region. && .AVIATION... Locally strong trades persist through tonight then slightly weaken on Tuesday. Clouds and showers favor windward and mauaka where isolated pockets of MVFR can be expected, especially as a remannt front drifts south over the islands tonight into tomorrow. Periods of MVFR, or even brief IFR, expected in showers. Otherwise, VFR prevails. AIRMET Tango remains in effect for low level turb aob 8kft. && .MARINE... A strong surface high pressure system far northwest of Kauai will drive fresh to strong trade winds through tonight. The high will briefly weaken on Tuesday, then strengthen north of the islands by late Wednesday. A large north swell combined with fresh to strong trade winds will keep rough seas in the forecast through the overnight hours. Small Craft Advisory (SCA) conditions are expected across all Hawaiian waters through tonight before falling below advisory thresholds on Tuesday as the north swell heights decrease. Winds and seas are forecast to drop below SCA levels by Tuesday for most marine zones. Due to the strength and direction of the current large northerly swell (340-360 degrees), moderate to heavy harbor surges are anticipated to continue in north facing harbors through tonight. A marine weather statement remains posted for this hazard, and this statement will continue through the tonight time period. The current large north swell will slowly decrease today and tomorrow, with advisory level surf affecting most north, east and west facing shores through tonight. A High Surf Advisory remains in effect for these affected areas. The latest nearshore and offshore buoy observations show a gradual decline in swell heights this morning, and the updated forecast guidance shows a gradual downward trend through the middle of the week. Surf heights will likely drop below advisory levels along north, east and west facing shores by early Tuesday morning. A small medium period swell may slightly boost north and west shore surf late Thursday into Friday, with small surf heights expected for next weekend. A series of overlapping small south swells will bring a decent boost to south shore surf starting today and continuing through the middle of the week. Surf heights along south facing shores will return to small mostly background levels from Friday into next weekend. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 AM HST Tuesday for Niihau-Kauai Leeward-Waianae Coast-Oahu North Shore-Olomana-Maui Windward West-Maui Leeward West-Kauai North-Kauai East-Koolau Windward- Molokai Windward-Molokai North-Molokai West-Maui Central Valley North-Windward Haleakala-Big Island East-Big Island North. Small Craft Advisory until 6 AM HST Tuesday for all Hawaiian waters- && $$ DISCUSSION...JVC AVIATION...JVC MARINE...Kino