Photo Credit: James Grenz

Hilo

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 at 4000 feet. South winds up to 10 mph shifting to the east in the afternoon. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 68 near the shore to around 54 at 4000 feet. Light winds. Chance of rain 30 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 85 near the shore to 69 to 74 at 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Kona

Today: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 69 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers early in the evening. Lows 69 to 75 near the shore to around 55 near 5000 feet. Light winds. Chance of rain 30 percent.

Wednesday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 82 to 87 near the shore to around 69 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 69 to 80 near 3000 feet. Light winds. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 68 near the shore to 56 to 62 near 3000 feet. Light winds becoming south up to 10 mph after midnight. Chance of rain 30 percent.

Wednesday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 69 to 80 near 3000 feet. Light winds. Chance of rain 40 percent.

Kohala

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 69 to 80 near 3000 feet. Light winds. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 68 near the shore to 56 to 62 near 3000 feet. Light winds becoming south up to 10 mph after midnight. Chance of rain 30 percent.

Wednesday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 69 to 80 near 3000 feet. Light winds. Chance of rain 40 percent.

South Big Island

Today: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to around 73 near 5000 feet. Southeast winds up to 10 mph shifting to the west in the afternoon. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 70 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 30 percent.

Wednesday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 73 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Puna

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 at 4000 feet. South winds up to 10 mph shifting to the east in the afternoon. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 68 near the shore to around 54 at 4000 feet. Light winds. Chance of rain 30 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 85 near the shore to 69 to 74 at 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the afternoon. Highs around 86 near the shore to 70 to 76 above 4000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers early in the evening. Lows 70 to 75 near the shore to 51 to 58 above 4000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to 70 to 76 above 4000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light winds and mostly dry weather will continue through today, with afternoon sea breezes bringing some clouds and a few showers to interior and upslope areas. A cold front is expected to move over the western islands on Wednesday, bringing a period of strong north winds and an increase in showers on Kauai and Oahu. The front will weaken into a trough and slowly shift westward Thursday through Friday, with showers favoring the western end of the state. Moderate to locally breezy trade winds and more typical windward and mauka focused showers will return over the weekend and hold in place through early next week.

Discussion

Currently at the surface, a cold front is located around 450 miles northwest of Kauai, while a 1020 mb high is centered around 1550 miles northeast of Honolulu with a ridge extending southwest to a position around 100 miles north of the Garden Isle. Observations indicate the presence of land breezes across the entire state early this morning. Infrared satellite imagery shows clear to partly cloudy conditions across most of the state, with a bit more cloud cover over portions of Kauai and the Big Island. Radar imagery shows rather dry weather with only a few showers brushing the windward coasts. Main short term concern revolves around the incoming cold front during the middle of the week.
Model guidance remains in good agreement showing the cold front approaching the state from the northwest today and tonight. The front is then forecast to push through Kauai Wednesday morning, Oahu Wednesday afternoon, then stall out and weaken over Maui County Wednesday night. Light winds will continue ahead of the front, with land and sea breezes dominant. Behind the front moderate to breezy trade winds will prevail. The front will weaken into a trough Thursday morning, then retrograde westward Thursday afternoon through Friday. Light winds will prevail Thursday with seas breezes developing in many areas. Moderate southerly flow is then forecast to develop Thursday night, tip southeasterly with trades gradually filling in across the eastern islands Friday and Friday night, with the trades then returning the western end of the state on Saturday. High pressure building north-northeast of the islands will then keep moderate to locally breezy trade winds in place Saturday afternoon through early next week.
As for the remaining weather details, rather dry conditions will prevail today. A few showers may move onshore into windward areas this morning, and a few may develop over the island interiors this afternoon. Dry conditions should continue tonight, with any shower activity remaining near the coast.
The cold front is forecast to bring some showery weather to Kauai Wednesday morning and Oahu by late Wednesday afternoon. Elsewhere, isolated to scattered sea breeze driven showers can be expected over Maui County and the Big Island Wednesday afternoon. Showers associated with the weakening front are expected to move into Maui County Wednesday night. As the front weakens into a trough and shifts westward Thursday through Friday, the shower coverage should be highest over the western half of the state, with drier conditions over the eastern islands. The pattern should transition over to a typical trade wind set up Friday night through early next week, with showers favoring windward slopes and coasts.

Aviation

A weak surface ridge located just north of Kauai, which is moving slowly southward, has caused the background trade wind flow to weaken. This light wind regime will continue through this evening, and will allow local nighttime land breezes and afternoon sea breezes to form over each of the individual islands. The atmosphere will also remain relatively dry and stable today.
The weak trade wind flow will transport some low clouds and brief trade showers into windward facing sections of some of the islands this morning. This may result in brief periods of MVFR conditions along windward facing slopes, but VFR will likely prevail across most of the state. By this afternoon, the sea breezes may produce increasing cloud cover over many leeward and interior sections of the island chain. However, shower activity is expected to be limited over most of the state.
No AIRMETs are currently in effect, and none are expected through this evening.
Looking ahead to early Wednesday morning, a front moving toward Kauai from the northwest will produce strengthening north winds over the far western end of the state. At the same time, the coverage of low clouds and showers may start to increase ahead of this front over portions of Kauai County and the adjacent waters.

Marine

Winds will be light to locally moderate through today as a weak surface ridge approaches the islands from the north. A front is then expected to reach Kauai by early tomorrow morning and Oahu tomorrow afternoon. Gusty north winds will fill in behind the front according to the most recent guidance, which will likely require a Small Craft Advisory (SCA). The front will weaken to a trough, and retreat west Thursday through Friday. Southerly winds will fill in behind the trough. A high will build far north- northeast of the islands over the weekend ushering the return of typical trade wind pattern.
The current northwest swell has subsided below High Surf Advisory thus the HSA has been cancelled. A larger, but shorter- period, north swell is expected to arrive tomorrow and may bring low-end advisory level surf to north facing shores tomorrow night and Thursday, before lowering Thursday night through Saturday. It will also likely bring SCA- level seas to exposed waters.
Small background south swells are expected through today, with a series of slightly larger, longer-period south swells expected tomorrow through Saturday. With no significant trade wind flow over and upwind of the state, most surf along east facing shores will be from north swell wrap through the week and slowly trend up over the weekend as trades return.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov