Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
589 FXHW60 PHFO 091945 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 945 AM HST Sat Nov 9 2024 .SYNOPSIS... Stable and breezy trade wind weather will prevail through late next week, with embedded low clouds and showers occasionally moving through the islands. Rainfall will favor windward slopes and coasts, particularly at night and during the early morning hours, with a few showers reaching leeward areas at times. && .DISCUSSION... A high far north of the main Hawaiian Islands is driving moderate to breezy trade winds across local waters this morning. Satellite loop shows scattered to patchy broken low clouds embedded within this flow piling up across windward and mauka sections of most islands. Leeward areas tend to have clearer skies, along with waters lee of the islands. Radar shows scattered to numerous showers moving into windward areas, with a few of these showers pushing leeward. Models show the high to our north will shift east and merge with a new building high to the distant northeast of the islands by late Sunday. This will keep the pressure gradient across the islands sufficiently steep to support breezy trade winds through the period. Trades could become quite strong late next week as the high moves southward and closer to the island chain. Expect a typical trade wind weather pattern for the next week or so, with embedded bands of low clouds and showers moving through. Rainfall will favor windward slopes and coasts, particularly at night and during the early morning hours, with a few showers reaching leeward areas at times as well. && .AVIATION... Breezy trade winds will continue through the weekend, with scattered showers primarily affecting windward and mountain areas. Lingering low-level moisture from a dissipated front will keep trade wind showers on the wetter side through the rest of this morning. Isolated MVFR conditions will be confined to windward areas, while VFR will dominate leeward areas. AIRMET Tango for moderate low level turbulence remains in effect over and down wind of all island mountains due to the breezy trade wind flow. && .MARINE... High pressure to the north of the state will shift to the north and east over the next several days and will maintain fresh to locally strong northeasterly trades through at least the middle of next week. A strong high pressure is then forecast to develop around the middle of next week. A Small Craft Advisory (SCA) remains in effect for the windier waters around Maui County and the Big Island and could be expanded to include additional waters next week. In the extended, there is growing confidence for trades to further strengthen as a northeast Pacific high becomes increasingly dominant. Strong trade winds could become widespread during the second half of next week with even gales possible for select channels. The current medium period NNW (320-350 degree) swell will gradually decline through Monday. A moderate NW (320 degree) swell is expected to take its place on Monday and will likely peak near advisory levels Monday evening. This swell will be followed by a larger NW (320 degree) swell filling in on Wednesday, which should produce advisory level surf for N and W facing shores. Surf along east- facing shores will remain rough and choppy through the middle of next week due to the breezy trade winds. Long range models are showing a significant increase of windswell towards the latter half of next week due to a large fetch of strong trade winds setting up over and upstream of the state. Surf should easily reach advisory thresholds (10 ft) and it may reach warning levels (15 ft) along east facing shores during its peak. Surf along south-facing shores will remain small and near the seasonal average through the middle of next week. Tiny long-period pulses will be possible over the next few days. Also with the peak monthly tides coming up towards the latter half of next week (Nov 14th to Nov 18th) we could see coastal inundation impacts during the early morning hours along all coastlines. The large windswell combined with the peak monthly tides could cause greater impacts along windward shores. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Powell AVIATION...TS MARINE...Tsamous