West Side

Today: Breezy. Sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs around 77. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Lows 63 to 69. Southeast winds up to 10 mph in the evening becoming light.

Martin Luther King Jr Day: Sunny. Isolated showers in the morning. Highs 75 to 80. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Mostly sunny. Highs around 80. Northwest winds up to 10 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows 60 to 70. Northwest winds up to 10 mph in the evening becoming light.

Martin Luther King Jr Day: Sunny. Highs around 82. Light winds becoming west around 10 mph in the afternoon.

North Shore

Today: Breezy. Partly sunny with scattered showers. Highs around 77 near the shore to around 61 near 5000 feet. Southeast winds up to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67 near the shore to around 47 near 5000 feet. Southeast winds up to 15 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.

Martin Luther King Jr Day: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 78 near the shore to around 63 near 5000 feet. Southeast winds up to 20 mph. Chance of rain 50 percent.

Central Maui

Today: Mostly sunny. Breezy. Highs 77 to 82. East winds up to 20 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows around 63. East winds up to 15 mph shifting to the south after midnight.

Martin Luther King Jr Day: Sunny. Highs around 81. South winds up to 15 mph shifting to the east in the afternoon.

Upcountry

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 57 at the visitor center to around 66 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 43 at the visitor center to around 45 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Martin Luther King Jr Day: Mostly sunny. Isolated showers in the morning. Highs around 59 at the visitor center to around 66 at the summit. East winds up to 15 mph. Chance of rain 20 percent.

East Maui

Today: Breezy. Partly sunny with scattered showers. Highs around 77 near the shore to around 61 near 5000 feet. Southeast winds up to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67 near the shore to around 47 near 5000 feet. Southeast winds up to 15 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.

Martin Luther King Jr Day: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 78 near the shore to around 63 near 5000 feet. Southeast winds up to 20 mph. Chance of rain 50 percent.

Lanai City

Today: Sunny in the morning then becoming partly sunny. Highs 68 to 75. Northeast winds up to 10 mph in the morning becoming light.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Lows around 61. Light winds.

Martin Luther King Jr Day: Sunny. Highs 69 to 76. Light winds.

Kaunakakai

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs 65 to 81. East winds 10 to 20 mph.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Lows 54 to 69. East winds up to 15 mph.

Martin Luther King Jr Day: Mostly sunny. Highs 66 to 82. Southeast winds up to 10 mph.

Detailed Forecast

Synopsis

Trades will give way to southeast winds later today as an upper level ridge axis moves across the state. Showers will be light and mainly in windward and mauka areas. A weakening cold front will move into the western part of the state Wednesday, but confidence is low on how far into the state it will get. Rainfall chances will increase in western counties Wednesday through Friday, and perhaps throughout the state. There is a chance that increased showers could linger through next weekend.

Discussion

Satellite showed areas of low clouds moving toward the state from the east-northeast under the influence of trade winds early this morning. There was just enough moisture for isolated light showers moving into some windward areas, but any precipitation amounts will be light, a few hundredths of an inch at most.
A surface high several hundred miles to our northeast will move farther northeast today, helping to shift our winds around to the southeast. This will begin to increase warmth and moisture into the coming week. Showers will increase slightly later today and a little bit more Monday and Tuesday.
Things change more significantly Wednesday, when a front will approach from the northwest. Driven by an upper level trough, reaching Kauai County Wed morning, then Oahu in the afternoon, and Maui County in the evening. Models diverge at this point, with important differences. Ensemble members show some solutions taking the front through Big Island, while others stall it out and begin to move it back to the west. But the speed at which it moves back west, and the amount of moisture associated with the remains of the front, vary amongst the solutions. At this point, all we can really say is that the chance of precipitation increases from west to east across the state Wednesday into Thursday, with an increased chance of showers likely remaining elevated over some parts of the state beyond Thursday. Clarity on this part of the forecast will probably take several more days as the models slowly converge on a solution.

Aviation

Moderate to locally breezy trades are expected to continue this morning before becoming southeast in most areas this afternoon. Brief, isolated to scattered showers are forecast over windward and mauka areas this morning, but will decrease this afternoon. Brief MVFR conditions are possible within these showers, with VFR conditions prevailing elsewhere.
AIRMET Tango remains in effect for low level turbulence downwind of terrain. This will likely be lifted later today as winds slightly weaken and veer southeasterly. A separate AIRMET Tango is also in effect for tempo moderate turbulence between FL240-FL320. This turbulence is expected to be out of the area around the time of the next issuance and will likely be dropped at that time.

Marine

The morning package continues a Small Craft Advisory (SCA) to the typical windier coastal waters, and adds most of the remaining coastal waters as the incoming northwest swell will bring SCA level seas to exposed areas today and into tonight. A High Surf Advisory (HSA) has also been posted to the north and west facing shores of Niihau, Kauai and Oahu, and the north facing shores of Molokai and Maui.
High pressure to the north of the state will continue to move to the east as a cold front moves towards the islands today. With the high pressure to the north, moderate to locally strong trade winds will continue today. As the cold front advances to the east towards the islands, winds will weaken and veer to the southeast. The front is expected to enter the offshore waters Tuesday, and will bring the possibility of thunderstorms to the northern offshore waters Tuesday through Thursday. The front is expected to reach the northwest coastal waters late Tuesday, and move over the central waters Wednesday where it will linger during the second half of the week.
The new moderate, long period, northwest swell reached the buoys to the northwest of the islands around midnight, and will reach Kauai later this morning. This swell will cause surf to rise rapidly along north and west facing shores. A High Surf Advisory (HSA) has been posted for the effected shores of the smaller islands. This swell is expected to peak in the islands this afternoon, with surf dropping below HSA levels tonight. Another moderate, long period, northwest swell is expected to arrive in the islands Tuesday, and linger through the middle of the week. This swell will maintain elevated surf along north and west facing shores.
The moderate to locally strong trade winds today will maintain rough and choppy surf along east facing shores. Additionally, some east facing shores sensitive to northerly swells may be experiencing a slight uptick in surf heights today as a fading north swell lingers. As winds weaken and veer to the southeast ahead of the incoming front, surf will lower along east facing shores. There are no noteworthy swells for the next few days for south facing shores.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
Small Craft Advisory until 6 AM HST Monday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov