Hilo

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 66 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 63 near the shore to around 49 at 4000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 82 near the shore to around 66 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly clear. Lows 63 to 70 near the shore to around 49 near 5000 feet. Light winds.

Monday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 30 percent.

Waimea

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 79 near the shore to 70 to 76 near 3000 feet. East winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 62 near the shore to 47 to 56 near 3000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 81 near the shore to 70 to 76 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 79 near the shore to 70 to 76 near 3000 feet. East winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 62 near the shore to 47 to 56 near 3000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 81 near the shore to 70 to 76 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

South Big Island

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 70 near 5000 feet. East winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly clear. Lows around 64 near the shore to around 49 near 5000 feet. East winds up to 15 mph.

Monday: Mostly sunny. Scattered showers in the afternoon. Highs around 84 near the shore to around 70 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 30 percent.

Puna

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 80 near the shore to around 66 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 63 near the shore to around 49 at 4000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 82 near the shore to around 66 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the afternoon. Highs around 84 near the shore to 65 to 72 above 4000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 64 to 70 near the shore to 44 to 52 above 4000 feet. Light winds.

Monday: Mostly sunny. Scattered showers in the afternoon. Highs around 84 near the shore to 65 to 72 above 4000 feet. Light winds. Chance of rain 30 percent.

Detailed Forecast

Synopsis

Trade winds will weaken and become more easterly as high pressure to our north moves eastward. Embedded clouds and showers will favor windward and mauka areas. Lighter winds expected next week may allow additional clouds and showers to form over interior areas during afternoon and evening hours. A more typical trade wind weather pattern is expected to return later next week as a new high builds to our north.

Discussion

A high persists far north of the area while clouds and showers have decreased noticeably since last evening. Radar shows little or no shower activity over the islands, but isolated to scattered light showers are noted over water southeast of the Big Island and across waters northeast of Oahu and Maui County. Moderate trade winds dominate, and we expect little change in this overall pattern through this morning.
Models show the high will drift eastward through Monday, causing local trade winds to weaken and veer a bit to a more easterly direction. Winds may be light enough Monday through Wednesday for development of daytime sea breezes and nighttime land breezes across some areas. Another cloud band will drift southward over the west end of the island chain, likely increasing showers for Kauai and Oahu Sunday night and Monday. With the lighter winds Monday and Tuesday, some showers may also form over interior areas during the afternoon hours.
A weak upper trough will move over the area from the west Tuesday through Thursday, decreasing airmass stability. With the trade winds expected to remain on the lighter side, the best chances for showers will be during the afternoon and evening hours due to daytime heating and sea breeze convergence. Temperatures may become cold enough aloft for a few thunderstorms to form over interior areas of the Big Island during the afternoon hours each day. A more typical trade wind weather pattern is expected to return by Friday and Saturday as a new high builds in to our north.

Aviation

Trade winds will weaken to light to moderate levels today as sea breezes begin to develop over terrain sheltered leeward slopes of each island. A convergent cloud band will drift into Kauai and Oahu later this afternoon and evening enhancing clouds and showers for both islands into Monday. Brief periods of MVFR conditions will develop over these western islands in showers. Otherwise mostly VFR weather conditions are expected with clouds building over island mountain and interior sections during the day with brief showers favoring the afternoon hours.
AIRMET for Mountain Obscuration remains in effect for north and east slopes of the Big Island this morning. This AIRMET may expand to North through East sections of Kauai and Oahu later this afternoon and evening.

Marine

Light to moderate easterly winds are expected through the start of the week as a couple of fronts pass to the north. A return of fresh to strong trade winds is expected late in the week as high pressure builds to the north.
Surf along north facing shores will trend up today as a short- period, northerly pulse arrives and moves through. This should linger into Monday along exposed coasts as the swell direction shifts out of the north to northeast.
A long-period, northwest swell associated with a compact storm quickly lifting north-northeast around 1500 nm north-northwest of the islands will arrive late Monday, then peak Tuesday through midweek. Surf should remain below the advisory levels for exposed north and west facing shores as it peaks.
For the long-range, guidance is advertising the active trend continuing as a broad area of gales setup over the far northwest Pacific near the western Aleutians focused at the islands within the 310-330 directional bands early this week. If this unfolds, expect a long-period, northwest swell later in the week that could drive surf heights to around advisory levels.
Surf along south facing shores will ease today as a south swell moves out. A smaller pulse expected Monday should be enough to keep the surf from going flat through the first half of the week.
Surf along east facing shores will trend down today as the trades weaken. The aforementioned north-northeast swell expected early in the week will support small surf continuing for exposed east facing shores.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov