Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
423 FXHW60 PHFO 230145 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 345 PM HST Sat Jun 22 2024 .SYNOPSIS... High pressure far north of the islands will maintain breezy trade winds through early next week. Passing showers will favor windward and mauka areas. Trades weaken slightly towards the middle of next week, with an uptick in showers possible late next week. && .DISCUSSION... Breezy trade winds continue this afternoon as the 1030 mb surface high remains approximately 825 mile north of the state. Meanwhile, stable conditions continue across the islands as a mid-level ridge remains in place over the region. Radar and satellite imagery show passing scattered showers over windward and mauka areas early this afternoon across the smaller islands. Wetter conditions continue across Windward Big Island this afternoon and will likely persist into this evening. Isolated showers over the Kona slopes of the Big Island will also continue through this evening. Guidance continues to show the strong surface high anchored north of the state through Monday which will maintain our breezy trade wind conditions. A stable and rather typical summertime rainfall pattern will prevail, leading to modest rainfall over windward slopes. Aside from some brief afternoon showers over Kona slopes of the Big Island, leeward areas will be mostly dry. Trades look to then weaken slightly to moderate strength towards the middle of next week as the high to our north finally weakens. An uptick in showers looks possible late next week as an upper- level disturbance approaches the region. && .AVIATION... Breezy to locally windy trades will continue through Monday. Showery cloud bands embedded within trade flow will produce periods of MVFR conditions across windward areas of each island at night and through the morning hours each day. Each afternoon will be clearer and drier. AIRMET Sierra remains in effect for tempo mountain obscuration for north and east slopes of Kauai, Oahu, Molokai, and Maui. The eastern slopes of the Big Island are also included in this AIRMET, which may need to be adjusted as cloud cover changes through each day. AIRMET Tango remains in effect for mod low level turb over and downwind of island terrain due to the breezy trade winds. This AIRMET will likely continue through Monday. && .MARINE... Strong easterly trades will continue into early next week, supporting the Small Craft Advisory in place for all waters. Seas will remain rough, with heights hovering around and just under the advisory level over exposed waters. Guidance shows a slight downward trend Tuesday through midweek due to the surface ridge potentially weakening to the north. Surf along east-facing shores will remain rough through early next week due to the aforementioned strong trades locally and upstream of the state. A gradual downward trend is possible Tuesday through midweek. Surf along south-facing shores will continue to trend up this weekend as a small south swell moves through. This should be short-lived, with a downward trend expected early next week. Despite a blocking high that has set up over our typical swell window near/southeast of New Zealand, a gale has formed to its northeast with the head of the fetch aimed at the islands within the 180 to 200-degree directional band. Given the shorter travel distance, surf associated with this source should trend up late next week. Surf along north-facing shores could trend up above flat levels early next week due to a small, medium-period northwest swell from a marginal gale lifting northeastward near the Aleutians. On its heels is a compact storm-force low, currently several hundred nautical miles east of Japan, that could send a similar northwest swell through the area late next week. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Monday for all Hawaiian waters- && $$ DISCUSSION...Ahue AVIATION...Powell MARINE...JVC