West Side

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 80. Northeast winds up to 10 mph. Chance of rain 60 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 72. South winds up to 15 mph. Chance of rain 30 percent.

Saturday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 78 to 83. South winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82. North winds around 10 mph. Chance of rain 30 percent.

Tonight: Partly cloudy. Lows 65 to 75. Light winds becoming southwest 10 to 15 mph after midnight.

Saturday: Mostly sunny. Breezy. Highs around 85. Southwest winds 10 to 20 mph.

North Shore

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to around 63 near 5000 feet. Light winds. Chance of rain 60 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 66 to 71 near the shore to around 50 near 5000 feet. Light winds becoming south up to 10 mph after midnight. Chance of rain 20 percent.

Saturday: Sunny. Highs around 82 near the shore to around 66 near 5000 feet. Southwest winds up to 15 mph.

Central Maui

Today: Partly sunny with scattered showers. Highs 77 to 82. North winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 64 to 69. East winds up to 10 mph shifting to the south after midnight. Chance of rain 20 percent.

Saturday: Sunny and breezy. Highs 81 to 86. Southwest winds 10 to 20 mph.

Upcountry

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 58 at the visitor center to around 67 at the summit. Southwest winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 45 at the visitor center to around 47 at the summit. Southwest winds up to 25 mph. Chance of rain 20 percent.

Saturday: Sunny and breezy. Highs around 61 at the visitor center to around 67 at the summit. Southwest winds up to 25 mph.

East Maui

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to around 63 near 5000 feet. Light winds. Chance of rain 60 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 66 to 71 near the shore to around 50 near 5000 feet. Light winds becoming south up to 10 mph after midnight. Chance of rain 20 percent.

Saturday: Sunny. Highs around 82 near the shore to around 66 near 5000 feet. Southwest winds up to 15 mph.

Lanai City

Today: Partly sunny with scattered showers. Highs 69 to 77. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 65. Light winds becoming south around 10 mph after midnight. Chance of rain 30 percent.

Saturday: Mostly sunny with isolated showers. Highs 71 to 79. South winds 10 to 15 mph. Chance of rain 20 percent.

Kaunakakai

Today: Partly sunny with scattered showers. Highs 66 to 83. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 57 to 71. Southeast winds up to 15 mph. Chance of rain 50 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs 69 to 86. South winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Remnants of a front linger over between Maui County and the Big Island will continue to dissipate, limiting rainfall across the state today. Light, southerly winds will prevail across the Hawaiian Islands through early tomorrow ahead of a stronger, more moisture- laden front tomorrow night from the northwest. As a result, enhanced showers and thunderstorms develop over the western end of the state, persisting through Tuesday.

Discussion

Latest observations from satellite imagery show the remnants of a front between Maui County and the Big Island will continue to dissipate. Radar imagery shows little rainfall associated with the front, granted most of the rainfall fell over portions of Oahu and Molokai throughout much of yesterday as the front initially advanced across the islands. Winds across the Hawaiian Islands remain light this morning allowing land breezes to develop through the day. Consequently, today should remain relatively dry, though a few lingering showers remain possible, namely across Maui County, where low-level moisture persists.
Additionally, latest observations from the Maunakea Weather Center continue to display advisory-level winds across the summits. Because of this, opted to extending the current Wind Advisory for the Big Island Summits out 6 more hours, now set to expire at 22z (12p HST LT) and to be reevaluated by the oncoming shift.
As the weekend approaches, winds will begin to pick up a bit from light to more moderate, and veer from the south across much of the state. Latest model guidance of the American model (GFS) and the European model (ECWMF) depicts another front advancing toward the islands from the northwest again; this one significantly stronger than the previous and more moisture-laden, posing a bigger concern for the impacted islands.
Guidance continues to depict an array of enhanced showers and periodic thunderstorms associated with the advancing front, initially to Kauai and surrounding waters Saturday night, then proceeding eastward to Oahu and Maui County by Sunday. The heaviest of the rainfall is expected to develop Sunday night through Monday, posing a potential threat for flash flooding, but this will largely hinge on the position of the heavy rain band as the front stalls somewhere over the western end of the state. There's a bit of a discrepancy between models in this regard, and therefore have opted to forgo any flood related products at this time as further analysis will be needed to determine the more likely scenario.
Upon the departure of supporting upper dynamics on Tuesday, the surface low escorting the front toward the Hawaiian Islands will move far north and weaken, leaving an orphaned frontal moisture band over the area through the latter half of the week. Some lingering showers will remain possible during this time. Otherwise, expect light to moderate southerly winds to prevail through the remainder of the forecast period.

Aviation

A remnant frontal boundary will continue to dissipate over Maui County this morning along with the associated low level stratus. Light to gentle winds over the state will allow for sea breezes to develop this afternoon that could increase chances of clouds and precipitation over interior areas, generating localized MVFR conditions, particularly around Maui County where low level moisture will linger. Otherwise, expect mostly VFR conditions to prevail today. Moderate southerly winds will develop over the western half of the state tonight with light southerly winds developing elsewhere as another front approaches the state from the northwest. Moderate to strong southwesterly winds will fill in around Kauai and Oahu Saturday along with increasing chances of CLD and SHRA.
AIRMET Sierra for tempo mountain obscuration above 2000 feet remains in effect for Maui County but maybe cancelled later this morning as conditions improve.

Marine

The remnants of a dissipating front over the eastern nearshore waters will generally maintain light variable or northerly breezes through the afternoon. As the islands fall downstream of the next approaching front from the northwest, gentle winds will veer around to the east southeast by tonight and become more southerly Saturday. This front is expected to come across the western island coastal waters late Saturday into early Sunday. Southwest winds along or ahead of the front may briefly strengthen to Small Craft Advisory (SCA) magnitudes around the islands of Niihau and Kauai Saturday night. Numerous showers with locally heavy rain and isolated thunderstorms are possible in association with this weekend's frontal passage. A moderate size northwest swell passage Sunday and Monday will likely elevate seas to SCA levels.
A moderate size, medium period northwest swell (330 degree) that peaked Thursday morning will be gradually declining through Saturday. A north pulse (350 degree) will move through today and Saturday. This will hold head high (or slightly higher) surf within the higher sets going into the weekend. A developing gale low just northwest of the offshore waters later today will send a similar moderate size, medium period northwest (310 degree) swell toward the state. This swell is scheduled to pass around the island chain Sunday and Monday and lift surf back up to High Surf Advisory (HSA) heights. A mix of smaller size, medium period north swells (350-010 degree) will arrive this weekend. These swells will assist in maintaining at least head high surf along many better northern exposed reefs into early next week.
East shore surf will remain small the next several days due to the absence of trade winds. Eastern exposures better exposed to north swell will experience an uptick in seas. Expect minimal background surf for south-facing shores. Southwestern exposures on primarily Kauai and Oahu may receive small to moderate choppy wind wave swell this weekend from strengthened southwest winds ahead of an approaching front.

Fire weather

Conditions remain below critical fire weather thresholds through the next several days. Winds are expected to remain light to moderate with relative humidity values steadily increasing associated with an incoming front. Temperature inversion heights over Maui and the Big Island will range from 5,500 to 6,500 feet today.

HFO Watches/Warnings/Advisories

Wind Advisory until noon HST today for Big Island Summits.

Data Courtesy of NOAA.gov