Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
146 FXHW60 PHFO 140649 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 849 PM HST Thu Jun 13 2024 .SYNOPSIS... A high pressure ridge will linger north of the Hawaiian Islands into next week producing moderate to breezy trade winds. Weak upper level troughing will keep brief periods of windward showers in the forecast favoring windward and mountain areas with drier conditions over leeward locations. Clouds and showers will develop along the Kona slopes of the Big Island each afternoon and evening. && .DISCUSSION... The satellite imagery this evening shows a band of unsettled clouds drifting into the windward slopes of the Big Island briefly enhancing overnight showers. Clouds drifting in on the easterly trade winds into the smaller islands are more stable in appearance. A subtropical jet stream moving into the Hawaii region from the west will spread high level cirrus clouds from west to east across the state through the weekend, enhancing sunrise and sunset colors. A high pressure ridge will linger through this weekend and into next week. This ridge will maintain 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 the trade wind temperature inversion heights between 5,000 to 7,000 feet for much of the forecast period. Expect brief showers at times, mainly over windward and mountain areas. Shower activity will trend higher in the overnight to early morning hours each day. Drier conditions are forecast over leeward locations. Not much day to day change in the weather forecast is expected over the next seven days. A slight increasing trend in the easterly trade wind speeds may develop by Wednesday of next week. && .AVIATION... A ridge north of the islands will maintain moderate to breezy trade winds over the next couple of days. Low clouds and showers will favor windward and mauka areas, and will bring brief periods of MVFR conditions. A few showers may make it over to leeward areas at times, but otherwise, VFR conditions should prevail. An enhanced areas of clouds and showers riding in on the trades upstream of the Big Island will bring MVFR conditions to the east side of the Big Island overnight. AIRMET Sierra has been posted for tempo mountain obscuration on the Big Island overnight. No other AIRMETs are in effect at this time. && .MARINE... Fresh to locally strong easterly trades will continue through the weekend as the surface ridge remains north of the area. A Small Craft Advisory (SCA) remains in effect for the windier channels and waters around Maui County and the Big Island through the weekend. The ridge may weaken a touch early next week which could ease winds to moderate to locally strong, however the SCA for the windier water may continue through the forecast period. Surf along south facing shores will hold steady as a small medium period south swell fades and forerunners of a fresh, long-period south swell fills in. Near shore buoys are already showing swell energy slowly climbing in the 20-18 second range. This swell could produce advisory level surf during the day Friday and reach near near warning-level surf late Friday and Saturday as the swell peaks. Current thought is to issue a High Surf Advisory (HSA) with the next package, and continue to monitor all observations to determine if a HSA needs to be upgraded to a High Surf Warning. A gradual downward trend is expected Sunday into early next week. After this swell moves out, very little swell is expected next week beginning around Tuesday. Tiny surf along north-facing will hold through tonight and become flat Friday over the weekend. A small medium period northwest pulses may provide a small 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... Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Bohlin AVIATION...M Ballard MARINE...Almanza