Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
224 FXHW60 PHFO 281340 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 340 AM HST Sat Jun 28 2025 .SYNOPSIS... Moderate to locally breezy trade winds will persist today then weaken and veer out of the east-southeast Sunday into early next week as a broad, weak trough develops and moves across the area. The lighter flow may allow for some isolated sea breeze showers across leeward areas, in addition to the typical windward and mauka showers. Midweek and beyond, the high to our northeast will gradually build and bring breezy trades to the area by next weekend. && .DISCUSSION... High pressure systems far northwest and northeast of Hawaii will maintain breezy trade winds today. Incoming low clouds and showers will focus across windward Kauai and Big Island this morning, likely decreasing over these areas around midday. Mostly dry conditions will persist across the rest of the state, but any clouds and showers that do move in will impact windward areas. Cirrus clouds filled in last night, but expecting these to move off to the east this morning. Leeward clouds from the daytime sea breezes will impact the Kona slopes on the Big Island this afternoon. Sunday into Monday, a board low level trough will develop over the islands as the high pressure systems become separated by front in the North Central Pacific. Winds will weaken and veer east southeasterly and guidance depicts an uptick in clouds and showers tracking in from the southeast. The instability provided by this weak troughing over/near the state combined with pockets of moisture moving in on the trades may be enough to enhance windward and mauka showers during the overnight hours with some spillage over into interior and leeward areas, and to help some clouds and showers build over island interiors and leeward areas in the afternoons where any sea breezes manage to develop in the lighter flow. A typical summertime upper trough near the state and above the low/midlevel trade wind inversion may contribute to some shower enhancement before the surface trough and associated moisture clears the islands to the west Monday night. Winds will remain lighter into Tuesday. The trades will build in Wednesday with a band of moisture from an old front that will track in from the east Wednesday night and Thursday. Then heading into next weekend, the surface high to our northeast will build, strengthening the local pressure gradient and bringing breezy easterly trades across the island chain. Overall, typical trade wind weather can be expected through the second half of the week with periods of windward and mauka showers. && .AVIATION... Breezy and stable trade wind weather will continue today. Brief MVFR ceilings and visibility possible with incoming windward showers. AIRMET Sierra is in effect for tempo mountain obscurationsfor windward sides of Kauai and the Big Island above 2500 feet likely continuing through the morning. Mostly dry and VFR conditions are expected elsewhere today. AIRMET Tango remains in effect for low-level lee turbulence caused by the breezy and stable trade winds. && .MARINE... Moderate to locally breezy trades are expected through at least Saturday as high pressure remains in place far northeast of the islands. A Small Craft Advisory has been extended for the typical windier waters and channels around Maui and the Big Island through Sunday 6AM. Early next week, a disturbance passing to the north of the islands may weaken the trades a bit as they veer to become slightly east-southeast. A tiny long-period reinforcement south swell should arrive this morning. Guidance remains in good agreement that a small, long- period south swell will arrive late Sunday into Monday. This swell is expected to boost south shore surf up to near the summertime average, peaking on Monday and then declining through much of next week. Surf along east shores will remain rough and choppy for the next couple of days due to the locally breezy trades. Surf along north facing shores will remain tiny throughout the next week. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Sunday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION/AVIATION...Foster MARINE...Walsh