Forecast Discussion

Synopsis

26 Apr 2024 14:01:00 GMT: Strong trade winds will gradually ease and veer toward the east- southeast through early next week. Plumes of moisture will produce passing showers across windward and mountain areas through Saturday. A drier weather pattern is expected Sunday into early next week with light to moderate east to east-southeast winds. Winds should be light enough for sea breezes to develop during the day and land breezes at night, especially early next week.

Discussion

26 Apr 2024 14:01:00 GMT: A 1032 mb high far northeast of the state is currently producing gentle to locally windy trade winds across the state this morning. Latest satellite and radar imagery shows low scattered clouds and showers riding in with the trade winds along windward areas with some of these showers spilling over to leeward locations of the smaller islands. There is also a veil of thin high clouds filling in from the west. Low clouds and showers may clear a little this afternoon but will soon be followed by another plume of moisture later this afternoon into Saturday. Shower will primarily be focused over windward areas with some spillage to leeward locales of the smaller islands. Rainfall amounts should remain light to moderate, due to stable conditions aloft. An area of low pressure will develop along a front today roughly 1000 miles northwest of the state and is expected to continue to develop through Saturday before shifting northeast. This set up will shift winds slightly to the east- southeast on Saturday for the western half of the state allowing for a hybrid wind pattern over the weekend with land/sea breezes developing over leeward areas of the smaller islands. There will still be an easterly component of the winds producing a moderate to locally breezy showers over windward areas, especially for the eastern half of the state. A trough extending from the low will inch roughly 500 miles northwest of the state early next week as the low tracks far north of the state early next week. This will further ease winds locally allowing for a more dominate land/sea breezes pattern. The surface trough and associated upper level trough will provide a conveyor belt, drawing a tongue of near to slightly above normal moisture levels over the state. These features could allow for taller clouds to develop each afternoon with the seas breezes, especially near Kauai. However rainfall totals are not expected to be significant. Expect clouds and chances of showers to diminish each night with the land breeze.

Aviation

26 Apr 2024 14:01:00 GMT: Nearly stationary surface high pressure to the distant NE of the islands will generally support locally strong ENE trade winds, but some subtle veering and weakening of the low-level flow is anticipated through tonight. AIRMET Tango for moderate low-level turbulence downwind of the terrain remains posted for now, with a chance it could be dropped later today. VFR conditions will prevail, especially leeward, with the stable island atmosphere strongly capped at heights between 6 and 8 kft. However, passing low cloud clusters will bring brief periods of MVFR CIG/VIS in SHRA, mainly to windward coasts and slopes.

Marine

26 Apr 2024 14:01:00 GMT: A 1031 mb surface high, centered about 900 nm northeast of the state, will slowly drift eastward over the next several days. Meanwhile, a new low is forecast to develop about 900 nm northwest of Hawaii today. Strong east-northeast trade winds are expected through channeled areas this morning, but should gradually weaken and shift to the east-southeast by Saturday in response to the approaching low. A Small Craft Advisory (SCA) remains in effect for all Big Island Waters as well as the more typically windy areas surrounding Maui and Molokai. Conditions are expected to end from the west late this evening or early Saturday. Surf heights will remain below advisory thresholds for all shores through the forecast period. Multiple small northwest swells are expected now through Saturday night. Expect these swells to produce small surf along north and northwest facing shores. A small southerly swell will lead to a slight bump in surf heights along south facing beaches through this afternoon. Strong trade winds will continue to produce choppy, rough surf along east facing beaches through this afternoon. Smaller, smoother surf is expected along east facing shores starting Saturday and continuing through the coming week.

HFO Watches/Warnings/Advisories

26 Apr 2024 14:01:00 GMT: Small Craft Advisory until 6 PM HST this evening for Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.