Photo Credit: James Grenz

Hilo

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 81 to 86 near the shore to 66 to 73 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 65 to 72 near the shore to 56 to 61 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Monday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 83 near the shore to 66 to 73 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Kona

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 82 to 89 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to 51 to 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Monday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 82 to 88 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 30 percent.

Waimea

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 68 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 64 to 72 near the shore to 56 to 64 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 67 to 88. East winds 10 to 15 mph. Chance of rain 40 percent.

Kohala

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 68 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 64 to 72 near the shore to 56 to 64 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 67 to 88. East winds 10 to 15 mph. Chance of rain 40 percent.

South Big Island

Today: Partly sunny. Scattered showers in the late morning and afternoon. Highs around 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 73 near the shore to around 53 near 5000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 85 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 81 to 86 near the shore to 66 to 73 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 65 to 72 near the shore to 56 to 61 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Monday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 83 near the shore to 66 to 73 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Waikoloa

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 82 to 90 near the shore to 66 to 74 above 4000 feet. Northeast winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows around 75 near the shore to 52 to 58 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Monday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 82 to 89 near the shore to 66 to 74 above 4000 feet. East winds up to 10 mph in the morning becoming light. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Light large scale southeast winds will become more easterly today as the subtropical ridge flattens out ahead of a stalling cold front far to the north of the Hawaiian Islands. Lighter large scale winds will continue into Tuesday with sea breezes developing from late morning to afternoon over all islands. Converging sea breeze winds will allow a few showers to develop over mountains and island interior sections by late afternoon to early evening. More stable down sloping land breezes will clear out most of the cloud cover over the islands. Trade winds will slowly strengthen from Tuesday afternoon onward with a return to windward and mountain cloud and shower activity from Wednesday onward, mainly in the overnight to early morning hours.

Discussion

The local radar imagery this morning shows rain falling along the northwest coast of the Big Island. Periods of moderate to locally heavy rain have fallen in this area, from leeward Kohala to Waikoloa Village to Kona, through the morning hours. These showers are produced by eddies just west of the Big Island, and in southeasterly wind flow these coastal showers can cause stronger than normal onshore winds to converge with the typical down slope mountain breezes.
Light southeast winds will shift to a more easterly direction today as an approaching cold front far north of the Hawaiian Islands flattens out the subtropical ridge just north of the state. Lighter large scale winds will continue to allow sea breezes to strengthen through the afternoon hours with clouds building over mountain and island interior sections. Increasing stability aloft with a lowering trade wind subsidence inversion will limit afternoon to early evening shower coverage into the first half of next week.
The cold front will weaken and stall north of the islands by Tuesday. Trade winds will strengthen from Tuesday afternoon onward and become moderate to locally breezy range by Thursday as this frontal trough erodes. The weather pattern will then shift back to windward and mountain areas with passing showers developing in the overnight to early morning hours from Wednesday night onward.

Aviation

A weak southeasterly flow will persist today across the state and allow for land breezes early this morning. By late morning and into the afternoon, sea breezes will likely develop, especially along the more sheltered leeward locations. Thus, scattered shower activity will be most concentrated over the interiors and elevated terrain. Isolated areas of MVFR ceilings and visibility may accompany these showers, though not expecting anything widespread.
There currently no AIRMETS in effect.

Marine

An area of low pressure remains far west of the state. Meanwhile, a weak ridge of high pressure is located just north of Hawaii. Expect light to moderate east to southeast winds to continue today. As the low tracks further west tonight, winds will back to more of an easterly direction and we should see light to moderate trade winds through the first half of the week. Wind speeds may approach Small Craft Advisory thresholds during the second half of the week.
South swell will remain elevated through today, then decrease through Tuesday, leaving only background south swell by the middle of the week. Minimal energy is expected from the south during the second half of the week. A small north-northwest swell is forecast to arrive around Wednesday followed by a slightly bigger pulse over the weekend. Light trade winds will keep small surf in the forecast along east facing shores through at least Wednesday with a slight increase expected towards the end of the week as the trades strengthen.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov