Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
651 FXHW60 PHFO 080147 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 347 PM HST Mon Jul 7 2025 .SYNOPSIS... Breezy to windy trades will persist through tomorrow, with the strongest winds focused across Maui County and the Big Island. Dry weather conditions will combine with these strong gusty winds to produce elevated fire danger across the state through tomorrow. Winds will ease starting Wednesday, with a ridge aloft confining brief passing showers to mainly windward and mountain areas. && .DISCUSSION... Strong high pressure to the north of the state will maintain a tight pressure gradient across the island chain and help drive breezy to windy trades through tomorrow. At the same time, a mid level ridge will remain situated over the state, maintaining stable conditions with temperature inversions lowering through tomorrow, which may help to enhance downsloping winds across lower elevation leeward communities. As such, a Wind Advisory remains in effect for the typical windier portions of Maui County and the Big Island through 6 PM HST tomorrow. The summits of Mauna Kea and Mauna Loa have also been included in the Wind Advisory as a mid level easterly jet streak moves overhead this evening through tomorrow. This afternoon`s radar and satellite imagery show clouds and showers moving into windward and mauka areas on the trades. Upstream moisture suggests that clouds and showers will focus over the eastern end of the state, with some drier air expected to filter over across the smaller islands tonight into tomorrow, helping to limit shower coverage across these areas. The pattern will begin to change on Wednesday as the center of the strong surface high to the north of the state lifts to the northeast. This will help to ease the local pressure gradient, and combined with the weakening of the mid level ridge and lifting of the inversion, the trades are expected to weaken slightly through the rest of the week. Pockets of moisture will filter in on the trades, bringing periodic upticks in windward and mauka shower coverage. && .AVIATION... Strong stability favors VFR with scattered showers and the occasional MVFR condition windward and mauka. Strong trades continue through Tuesday. AIRMET Tango for lee turb remains in effect. && .MARINE... High pressure will remain nearly stationary far north of the islands through Tuesday, which will support continued fresh to strong trades across the area. As a result, a Small Craft Advisory remains in effect for all Hawaiian coastal waters through 6 PM HST Tuesday. The surface high will move eastward and weaken slightly during the second half of the week, but winds are likely to remain breezy to locally strong in the windier channels and waters of Maui County and the Big Island. Therefore, the SCA will likely need to be extended for these areas. Additionally, seas may also approach 10 feet at times in the Alenuihaha Channel over the next couple of days. South shore surf is expected to slowly decline as the current small south swell fades through early Tuesday. The next small, long-period south swell is expected to arrive Tuesday evening and peak on Wednesday. This swell may boost south-facing shore surf heights slightly from Tuesday night through Wednesday before gradually easing again through Friday. Guidance shows that another, smaller long-period reinforcement could arrive Friday night into the first half of the weekend. Surf along east-facing shores will be rough and choppy for the next couple of days in response to the gusty easterly trade winds. As the trades ease a bit during the latter portion of the week, surf along east-facing shores will also trend down. && .FIRE WEATHER... Breezy to windy trade winds with stable and relatively dry conditions will persist through tomorrow. Minimum relative humidity at lower leeward elevations will likely fall to around 45 percent each afternoon, and with the inversion dropping to as low as 5,000 feet, winds will become gusty over and downwind of island mountains. This will result in near critical fire weather conditions over dry leeward areas at times, though no headlines (watches or warnings) are due since the Keetch Byram Drought Index will remain below the 600 threshold at Honolulu. && .HFO WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 6 PM HST Tuesday for Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Kohala-Big Island Summits- Molokai-Lanai Windward-Lanai Leeward-Lanai South-Maui Central Valley North-Maui Central Valley South-Windward Haleakala-South Haleakala-Big Island South-Big Island Southeast-Big Island North. Small Craft Advisory until 6 PM HST Tuesday for all Hawaiian waters- && $$ DISCUSSION...Farris AVIATION...JVC MARINE...Vaughan FIRE WEATHER...Farris