Moderate to breezy trade winds produced by strong high pressure far northwest of the Hawaiian Islands will increasingly back northeast ahead of an approaching Hurricane Fausto tonight into Tuesday. Shower activity should also experience an uptick, but continue to favor windward mountain areas through early Tuesday. As Fausto passes north of the Hawaiian Islands on Tuesday and Wednesday as a tropical storm, diminishing winds for the islands could allow for sea breezes and heavy afternoon rain showers. A drier, breezy trade wind weather pattern will return across the state from Thursday onward as Fausto drifts westward away from the Hawaiian Islands.
This evening, numerous low clouds and showers are moving into north through east sections of all islands. Latest surface observations and satellite imagery show widespread MVFR ceilings and visibilities, with isolated IFR conditions. As a result, AIRMET Sierra has been issued for mountain obscuration for windward sections of all islands. This AIRMET will likely remain in place throughout the night. Should IFR conditions become a bit more widespread, this AIRMET may need to be upgraded.
Meanwhile, as Tropical Storm Fausto draws closer (but remains north of the islands), trade winds will weaken and become more northeasterly tonight and Tuesday over the eastern end of the state, followed Oahu and Kauai Tuesday night. As light southeast to south winds will develop and spread over the state from east to west, sea-breeze induced showers will increase. MVFR or isolated IRF conditions are possible in heavier showers, but otherwise, VFR flight conditions are expected to prevail. Aviation interests near the Hawaiian Islands should monitor updates to TC SIGMET Sierra, which covers Fausto, as the system passes north of the islands over the next few days.
Moderate to fresh NNE winds will be in place tonight as Hurricane Fausto enters the far northeast offshore waters. Winds will become more north and decrease tonight into Tuesday as Fausto moves through the northeast and northern offshore waters. As Fausto passes by, winds will be light and variable over the coastal waters, followed by south, then southeast immediately in its wake. As Fausto moves off to the northwest and high pressure builds to the north, east- northeast trades will build back in on Thursday then strengthen to fresh to locally strong levels on Friday into the weekend. A Small Craft Advisory (SCA) remains in effect for the winder waters and channels around Maui County and the Big Island through the remainder of the afternoon. Additionally a SCA is now in effect for the windward waters due to the east swell through Tuesday night.
Nearshore buoys on the eastern side of the islands have shown a considerable uptick with the medium and long period energy from Fausto. The surf is expected to continue building through the evening and then peak tomorrow before dropping off Wednesday afternoon. A High Surf Warning for east facing shores is currently in effect through Wednesday afternoon. East shore surf will then trend back up Friday into the weekend due to a combination of rising trade wind swell and a new long period east swell generated by Hurricane Genevieve.
A series of south swells will keep south shore surf near the summertime average (5-6ft) through the week.
Surf along N shores could also see some brief increase as Fausto (or its remnants) pass near the region Tuesday and Wednesday, then return to typical flat to tiny levels late Wednesday into the weekend.
High Surf Warning until 6 PM HST Wednesday for Big Island East- Big Island North-Big Island Southeast-East Honolulu-Kauai East- Kipahulu-Koolau Windward-Maui Windward West-Molokai Southeast- Molokai Windward-Olomana-Windward Haleakala.
Small Craft Advisory until 6 AM HST Wednesday for Alenuihaha Channel-Big Island Southeast Waters-Big Island Windward Waters- Kaiwi Channel-Kauai Northwest Waters-Kauai Windward Waters-Maui County Windward Waters-Oahu Windward Waters-Pailolo Channel.
