433 FXHW60 PHFO 110114 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 314 PM HST Thu Apr 10 2025 .SYNOPSIS... Moderate to breezy trade winds will continue through early next week with clouds and showers generally favoring windward and mauka areas. Enhanced showers will be possible through tonight and again next week as moisture from a dissipated front moves in on the trades and a few upper level disturbances move overhead. By Wednesday, a transition to east-southeast winds may occur and lead to a hybrid east-southeast flow and land/sea breeze pattern. && .DISCUSSION... A plume of leftover moisture from a dissipated front continues to stream across the state this afternoon on the moderate to breezy trades. With the instability from the exiting upper level trough, elevated inversion heights, and this current plume of moisture moving across the island chain tonight, clouds and showers will move into windward and mauka areas on the trades with a fair amount of showers passing over the terrain to impact leeward areas, as well. A 1035mb surface high to the far north of the state will slide eastward over the next couple of days, helping to maintain moderate to breezy trades across the region - with just a slight decline in wind speeds as compared to today. These moderate to breezy trades will deliver clouds and showers to windward coasts and slopes as a long band of moisture reaching far upstream moves across portions of the island chain through the weekend. However, mid-level ridging will temporarily build overhead as the broad upper level trough pushes off to the east, which will help to lower inversion heights, put a slight damper on shower activity, and bring a more typical distribution of windward/mauka showers tomorrow through the weekend. Early next week, a mid-level low will move over the state from the west with a broad upper level trough quickly following, both of which will act to add some instability back over the area. At the surface, the high to the far northeast will weaken in response to a cold front moving across the eastern Pacific, allowing the local pressure gradient to relax slightly and bring moderate to locally breezy trades across the state. Batches of moisture caught up in the trades will bring periodic clouds and showers that will occasionally spill over to leeward areas at times. Depending on the progression of a front moving through the Central Pacific midweek next week, wind directions may begin to shift from a more east-southeasterly direction on Wednesday, which would allow land and sea breeze activity to expand in coverage across the state. However, current model guidance is not in good agreement on the pattern that far out at this time. && .AVIATION... Moderate to breezy trade winds will continue for the next few days with the breeziest winds, both surface and aloft, expected over the western end of the state. AIRMET Tango is now in effect for low level mechanical turbulence to the lee of higher terrain Kauai and Oahu. Bands of light showers carried by the trade winds will impact mainly windward slopes and coasts and be most active in the late night and morning hours. AIRMET Sierra for mountain obscuration is now in effect for north and east facing slopes of Kauai, Oahu, Molokai, and Maui. On the Big Island, localized sea breezes along the leeward coast are driving cumulus development over the island`s interior. Partial clearing expected after sunset along south and west facing slopes of the Big Island. && .MARINE... Fresh to strong trade winds will prevail through Friday as robust surface high pressure north of the state creeps eastward, with most waters under a Small Craft Advisory (SCA). The pressure gradient and resulting trades will be strongest along and just north of a band of moisture that will linger around Kauai and Oahu. Winds will ease slightly Friday night and Saturday as the high moves to the east and its associated surface ridge is weakened and displaced southward toward the state. During this time, the SCA will likely be trimmed back to the typically windy waters around the Big Island and Maui County. A further decrease in trades is possible by Tuesday as the surface ridge is pushed closer to the islands. A series of small northwest to north-northwest swells will produce surf below April average on northern shores through most of the week. A mix of declining north-northwest swell and a fresh northwest swell of around 3 to 4 feet at 12 seconds has been observed on the local PacIOOS buoys at Hanalei and Waimea Bay, maintaining small surf. The new swell will slowly decline Friday afternoon through the weekend. A slightly larger northwest swell is expected to build on Monday and decline Tuesday and Wednesday. Strong trade winds over and upstream of the islands will produce elevated rough surf along east facing shores through Friday. The largest wind waves have been observed near Kauai, where the PacIOOS buoy has been reporting over 8 feet at 8 seconds, and as these seas peak overnight, east shore surf will be just below the High Surf Advisory level on Kauai. The elevated seas will also contribute to the need for a SCA around Kauai and Oahu. Surf along eastern shores fall to near April average statewide on Saturday and decline below average Sunday into early next week. South shore surf will be near April average through Friday, then decline to summertime background levels during the weekend. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Friday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel- Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui County Windward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Farris AVIATION...Bedal MARINE...Wroe