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Hawaii Island Weather Outlook for May 8th, 2021

All-weather advisories for the Island of Hawaii have been canceled and a normal and stable weather pattern expected to slowly take over during the Mother's Day Weekend.

Published by: HIRSC - Weather Team


Moderate to breezy trades will remain into next week. Clouds and showers will focus over windward and mountain areas with an occasional shower reaching leeward locations. Some brief heavier showers will remain possible over Kauai into the weekend.


An upper-level trough is maintaining some instability over the western end of the state with some isolated heavier showers moving westward over the coastal waters south of Kauai. These showers could bring some brief downpours over Kauai tonight and Saturday. High pressure parked far northeast of the islands will maintain easterly trade winds through the forecast period. Showers riding the trade winds will push into the windward slopes bringing periodic clouds and rainfall. Some of these showers will reach leeward locations of the smaller islands. Weak upper-level troughiness will persist into next week favoring an elevated inversion and a slightly wetter variety of trade wind weather. For the leeward Big Island, afternoon sea breezes and heating will allow for clouds and sporadic showers before clearing through the overnight and early morning hours. Some increasing showers are possible late next week as another upper trough approaches the state.


Moderate to locally breezy trade winds are returning to the state, and have prompted AIRMET Tango for low-level mechanical turbulence to the lee of the mountains on all islands. Expect this AIRMET to stick around through Saturday. However, winds are expected to weaken a bit Saturday night as high pressure to the northeast moves away from the islands. Clouds and showers are being carried in on the trade winds, and are at times producing MVFR and brief IFR conditions mainly over the north and east sides of the islands. AIRMET Sierra is in place for some mountain obscuration on the Big Island where clouds and showers are a little more concentrated. Expect AIRMET Sierra to persist through the night, and conditions may linger longer.


With surface high pressure centered far NE of the area and a broad surface trough to the W of the islands, moderate to locally strong trade winds have veered just slightly S of E. A Small Craft Advisory (SCA) is posted for waters around Maui County and the Big Island through Saturday. Although little significant change is expected through the weekend, a front passing far N of the area may lead to a marginal weakening of the wind Sunday. As the trough to the W eventually dissipates next week, the moderate to locally strong trade winds will back to the more typical ENE direction. Surf along all shores will remain below High Surf Advisory levels through next week. A small NW swell is expected to arrive Sunday before slowly diminishing Monday through Wednesday. Small swells arriving from the southern hemisphere will bring a small increase in surf heights along S facing shores this weekend, and will likely keep surf from going flat for most of next week. Trade winds will deliver relatively small, short-period waves to E facing shores.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

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