Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
396 FXHW60 PHFO 150139 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 339 PM HST Fri Jun 14 2024 .SYNOPSIS... High pressure will linger northeast of the Hawaiian Islands into next week, producing moderate to breezy trade winds. Weak upper level troughing will keep brief showers in the forecast, favoring windward and mountain areas. Drier conditions are expected for leeward locations. Additionally, clouds and showers will develop along the Kona slopes of the Big Island each afternoon and evening. && .DISCUSSION... This afternoon, high pressure remains situated far northeast of the main Hawaiian Islands. This feature is producing moderate to breezy easterly trade winds across the state. Meanwhile, limited moisture embedded within the trades is producing isolated showers along mainly windward and mountain locations, but rainfall totals today have been light. In the upper levels, a subtropical jet over the islands is streaming thin cirrus overhead. This jet is expected to weaken during the second half of Saturday. The surface high far northeast of the islands will linger through this weekend and into next week, maintaining a fairly typical moderate to breezy trade wind weather pattern into the foreseeable future with little day-to-day variation. Weak upper level troughing will keep inversion heights between 5,000 and 7,000 feet for much of the forecast period, with the exception of the second half of the weekend. Expect brief showers at times, mainly over windward and mountain areas. It is possible that a weak low- level easterly wave on Saturday night could produce a slight boost to shower activity through Sunday morning. Otherwise, showers will be fairly brief and light, and coverage will be greatest during the overnight to early morning hours each day. Drier conditions are forecast over leeward locations, with the exception of the Kona slopes of the Big Island, where daytime surface convergence will increase clouds and introduce isolated showers each afternoon. Not much day-to-day change in the forecast is expected over the next seven days. Increasing trends in the easterly trade wind speeds may develop next week from Wednesday onward. && .AVIATION... Moderate to breezy trades should continue over the next few days. Low cigs and SHRA will favor windward and mauka areas, with brief periods of MVFR conds possible. A few SHRA may make it over to leeward areas at times, but otherwise VFR conds should prevail. AIRMET Sierra is in effect for mtn obsc for windward Big Island as well as windward portions of Maui, Lanai and Molokai. && .MARINE... Easterly trades will remain locally breezy through the weekend and much of next week as a surface ridge persists north of the area. A Small Craft Advisory (SCA) in effect for the windier channels and waters around Maui County and the Big Island has been extended through the weekend. The ridge may weaken slightly early next week, causing winds to decrease a bit. However, the SCA for the windier waters may continue through the forecast period. The High Surf Advisory for all south facing shores has been upgraded to a High Surf Warning (HSW) as a long period south swell continues to gradually build and surf observations show spotty surf heights reaching warning threshold. This HSW is in effect through noon Saturday. A gradual downward trend is expected after Saturday into early next week. After this swell moves out, very little swell is expected next week after Tuesday. North-facing shore surf will become flat for the next few days. Small medium period northwest pulses may provide a tiny bump Sunday night into middle of next week. Surf along east-facing shores will remain small and choppy each day due to a limited trade wind fetch upstream of the islands. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Warning until noon HST Saturday for south facing shores. Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Vaughan AVIATION...Walsh MARINE...Powell