Hilo

Today: Partly sunny with scattered showers. Highs around 80 near the shore to 64 to 69 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 67 near the shore to around 51 at 4000 feet. Light winds. Chance of rain 60 percent.

Memorial Day: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with numerous showers in the afternoon. Highs 79 to 84 near the shore to around 64 near 5000 feet. Light winds becoming northwest up to 10 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy. Numerous showers early in the evening, then isolated showers in the late evening and overnight. Lows 65 to 72 near the shore to around 52 near 5000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 70 percent.

Memorial Day: Sunny in the morning, then mostly cloudy with numerous showers in the afternoon. Highs 80 to 85 near the shore to around 65 near 5000 feet. Light winds. Chance of rain 70 percent.

Waimea

Today: Partly sunny with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 64 near the shore to 52 to 59 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Memorial Day: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to 65 to 75 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Kohala

Today: Partly sunny with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 64 near the shore to 52 to 59 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Memorial Day: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to 65 to 75 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

South Big Island

Today: Mostly sunny in the morning, then mostly cloudy with numerous showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Numerous showers early in the evening, then isolated showers late in the evening. Lows around 66 near the shore to around 51 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Memorial Day: Breezy. Mostly sunny in the morning, then mostly cloudy with numerous showers in the afternoon. Highs around 83 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Puna

Today: Partly sunny with scattered showers. Highs around 80 near the shore to 64 to 69 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 67 near the shore to around 51 at 4000 feet. Light winds. Chance of rain 60 percent.

Memorial Day: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny in the morning, then partly sunny with numerous showers in the afternoon. Highs around 83 near the shore to 65 to 71 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers early in the evening, then mostly cloudy with isolated showers late in the evening. Partly cloudy after midnight. Lows 66 to 72 near the shore to 48 to 55 above 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Memorial Day: Sunny in the morning, then partly sunny with numerous showers in the afternoon. Highs around 84 near the shore to 66 to 72 above 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Trade winds will remain on the lighter side today, then gradually strengthen tonight and Memorial Day, with moderate to locally breezy conditions prevailing Tuesday into next weekend. Clouds and showers will generally favor windward areas during nights and mornings through the holiday weekend, with the lighter winds allowing for scattered shower development over leeward areas each afternoon. A more typical trade wind pattern featuring mainly windward showers and the occasional leeward spillover should return Tuesday and linger through next weekend.

Discussion

Currently at the surface, a 1031 mb high is centered around 1250 miles north of Honolulu, with a weak trough of low pressure a few hundred miles north of the state. The trough to the north continues to influence the winds locally, keeping trades in the light to moderate range, with localized land breezes present in many areas. Infrared satellite imagery a mix of high and low clouds producing partly to mostly cloudy conditions. Meanwhile radar imagery shows isolated to scattered showers moving into windward areas, with dry conditions in most leeward locales. Main short term focus revolves around rain chances and trade wind trends.
The trough of low pressure north of the state will shift westward and dampen out during the next couple days, while a new strong high builds to the distant north. Light to moderate trades will prevail today, with localized sea breezes developing in protected leeward areas. The trades will then gradually strengthen to moderate levels tonight and Memorial Day, with moderate to locally breezy trades prevailing Tuesday into next weekend as the high to the north persists.
As for the remaining weather details, shower activity should remain confined to mainly windward areas this morning. Daytime heating and localized sea breezes should bring another round of scattered showers to the island interiors and leeward areas this afternoon, with the activity then gradually waning through the evening hours. A gradual return to more typical trade wind weather is expected tonight and Memorial Day, with showers favoring windward areas during the night and morning hours, along with scattered shower development in leeward areas Monday afternoon. Trade wind weather will then prevail Monday night into next weekend. Showers will favor windward and mauka areas, although a few showers will reach leeward areas at times as well due to the elevated inversion resulting from troughing aloft holding in place just to the north of the state. The troughing aloft should result in a slightly more showery trade wind pattern, along with periods of scattered to broken cirrus moving through.

Aviation

A high pressure ridge far north of the region and a broad low level trough north of the islands will keep light to moderate trade winds in the forecast today with day time sea breezes mainly along western slopes of each island. Clouds and brief showers will favor mountain and island interior sections in the afternoon and early evening hours. Trade winds will begin to strengthen by tonight, increasing shower trends along windward slopes of all islands. Brief MVFR conditions are possible in any showers that develop, otherwise VFR conditions will prevail.
There are no AIRMETs currently in effect.

Marine

Light to moderate easterly trade winds will continue today, then increase into the moderate to fresh range tonight into Monday as high pressure builds to the north. A return of locally strong easterly trades is possible by midweek from Maui County to the Big Island over the typically windier waters.
Surf along south facing shores will remain up through the early portion of the week as small pulses out of the south-southwest direction from recent activity moving through the Tasman Sea continue. The next pulse is expected tonight, which should linger through midweek. A brief lull is then expected through the latter half of the week, followed by a similar background, long-period south-southwest swell next weekend.
Surf along east facing shores will hover near flat levels due to the trades backing down locally and far upstream across the eastern Pacific. A slight increase in choppy surf is expected through the week as the trades return to moderate/fresh levels.
Surf along exposed north and west facing shores will see a slight increase out of the west-northwest tonight through Tuesday from a recent system lifting northeastward over the far northwest Pacific. Otherwise, back to the summertime average for the rest of the week. For the long range, WAVEWATCH III does highlight a potential small, long-period west swell associated with Tropical Cyclone Mawar in the far northwest Pacific arriving around June 6th (low confidence).

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov