Photo Credit: James Grenz

Hilo

Today: Mostly cloudy with scattered showers. Highs around 82 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then frequent showers after midnight. Lows around 69 near the shore to around 55 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.

Tuesday: Mostly cloudy. Frequent showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 90 percent.

Kona

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Southwest winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 70 to 75 near the shore to around 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 40 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 66 to 83. East winds 10 to 20 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 69 near the shore to 57 to 63 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 66 to 83. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 70 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs 66 to 83. East winds 10 to 20 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 69 near the shore to 57 to 63 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 66 to 83. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 70 percent.

South Big Island

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 71 near the shore to around 54 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy with scattered showers. Highs around 82 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then frequent showers after midnight. Lows around 69 near the shore to around 55 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.

Tuesday: Mostly cloudy. Frequent showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 90 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 73 near the shore to 52 to 59 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny in the morning then becoming partly sunny. Breezy. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 20 mph.

Detailed Forecast

Synopsis

Moderate to breezy easterly trade winds are expected to persist through the week, with clouds and showers favoring windward and mauka locations overnight through the mornings. Shower coverage is expected to increase tonight through midweek as an area of moisture associated with former Tropical Cyclone Adrian moves through from east to west. Drier trade wind conditions will return through the second half of the week through next weekend.

Discussion

Guidance remains in good agreement and depicts moderate to breezy easterly trades holding through the week as the surface ridge remains anchored to the north. Clouds and showers will favor windward and mauka locations each day, with a potential increase in coverage tonight through midweek as a large area of enhanced low-level moisture moves through from east to west. This increase in moisture combined with a weak mid-level trough and the trade wind inversion lifting to 8-10 kft may allow a few more showers to make it over our dry leeward locations of the smaller islands overnight through the mornings. A return of drier trade wind conditions is anticipated through the second half of the week through next weekend as the area of moisture shifts west of the islands and mid-to-upper heights rise. These higher heights could lead to temperatures climbing slightly above average each day.

Aviation

Moderate to breezy trade winds will likely persist through this afternoon. Low clouds and showers carried by the low-level trade wind flow will continue to move across windward facing slopes and coastal areas this morning. Brief periods of MVFR conditions may occur along some windward areas, with isolated mountain obscuration possible over some higher terrain. Otherwise, expect VFR conditions to prevail across most of the state today.
AIRMET Tango remains in effect for Tempo moderate low-level turbulence over, and downwind of the higher terrain of all islands due to the strong trade winds. This AIRMET will likely continue through this afternoon based on the latest guidance.
By tonight, increasing low-level moisture is expected to begin moving in from the east. The coverage of low clouds and showers may increase, especially over the windward sections of the Big Island and Maui. This may result in widespread MVFR conditions developing later tonight over windward facing slopes of the eastern islands. This enhanced moisture may then spread to the central and western end of the island chain on Tuesday.

Marine

A ridge of high pressure north of the islands will keep moderate to locally strong trade winds in place through the weekend. A Small Craft Advisory is now in effect for the typically windy waters around Maui and the Big Island through Tuesday, and this will likely need to be extended through much of the week.
Surf along south facing shores will remain near or above the summertime average through Thursday, with a peak expected Tuesday and Wednesday. South shore surf will then decline to mainly background levels Friday through next weekend.
Surf along north facing shores will hold at typical summertime levels during the next 7 days. East shore surf will change very little through the weekend, remaining at slightly below normal levels.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov