West Side

Rest Of Today: Partly cloudy early in the morning then becoming mostly cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms. Locally heavy rainfall possible in the morning. Highs around 80. Light winds becoming southwest around 10 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 67 to 73. Light winds. Chance of rain 50 percent.

Saturday: Mostly sunny with isolated showers. Highs around 81. South winds up to 10 mph shifting to the northeast around 10 mph in the afternoon. Chance of rain 20 percent.

South Side

Rest Of Today: Partly cloudy early in the morning then becoming partly sunny. Isolated thunderstorms and showers in the morning. Scattered showers and isolated thunderstorms in the afternoon. Highs around 84. Light winds becoming south up to 10 mph in the morning, then shifting to the southwest around 10 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy. Isolated showers in the evening. Lows 66 to 75. Light winds. Chance of rain 20 percent.

Saturday: Mostly sunny. Highs around 86. Southeast winds up to 10 mph shifting to the north around 10 mph in the afternoon.

North Shore

Rest Of Today: Partly cloudy early in the morning, then partly sunny with isolated showers and thunderstorms in the morning. Mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 71 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 50 percent.

Saturday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 81 near the shore to around 65 near 5000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Central Maui

Rest Of Today: Mostly sunny early in the morning then becoming partly sunny. Isolated showers early in the morning. Isolated thunderstorms. Scattered showers in the afternoon. Highs 81 to 86. Light winds becoming south up to 10 mph in the morning, then shifting to the southwest around 10 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 69. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 81 to 87. Southeast winds up to 10 mph shifting to the northeast around 10 mph in the afternoon. Chance of rain 20 percent.

Upcountry

Rest Of Today: Partly cloudy early in the morning then becoming mostly cloudy. Isolated showers and thunderstorms in the morning. Scattered showers and isolated thunderstorms in the afternoon. Locally heavy rainfall possible in the afternoon. Highs around 60 at the visitor center to around 57 at the summit. South winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 47 at the visitor center to around 44 at the summit. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Saturday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 61 at the visitor center to around 66 at the summit. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 50 percent.

East Maui

Rest Of Today: Partly cloudy early in the morning, then partly sunny with isolated showers and thunderstorms in the morning. Mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 71 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 50 percent.

Saturday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 81 near the shore to around 65 near 5000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Lanai City

Rest Of Today: Mostly cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms. Locally heavy rainfall possible. Highs 71 to 79. Light winds becoming south around 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 66. Southeast winds around 10 mph. Chance of rain 50 percent.

Saturday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 72 to 80. Southwest winds around 10 mph shifting to the northwest in the afternoon. Chance of rain 30 percent.

Kaunakakai

Rest Of Today: Mostly cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms. Locally heavy rainfall possible. Highs 70 to 85. South winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 57 to 73. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 69 to 86. Light winds becoming north around 10 mph in the afternoon. Chance of rain 40 percent.

Detailed Forecast

Update

Thunderstorms have been added to the forecast for the central islands (Maui County and Oahu) and the surrounding waters, as thunderstorms have developed and are moving northward.

Synopsis

A weakening trough near Kauai will continue to bring showers to the Garden Isle today. Additional moisture moving into the islands will continue the chance for showers statewide through the weekend. Southerly winds through the weekend will give way to returning trade winds Monday, which will carry showers into the islands early next week.

Discussion

A northeast to southwest oriented trough near Kauai brought showers and thunderstorms to the area overnight. While additional showers and even some thunderstorms remain possible, the main threat for flooding has diminished, and so the Flood Watch was cancelled this morning.
The forecast has been updated to trend towards the National Blend of Models (NBM), however there haven't been any significant changes with the morning package. A change for today has been an increase in PoP for the central islands (Maui County and Oahu). The NBM appears to have locked on to an area of clouds and showers a little over 100 miles south of Oahu at 330 am, that is moving north. Thunderstorms remain in the forecast for today over and around Kauai, however there are some indicators in the models to suggest that thunderstorms could still be possible tonight and tomorrow, and even over the central islands. However there is conflicting guidance, so confidence is low, so have left thunderstorms only in for today near Kauai.
The trough is expected to weaken over the next 24 hours, although southerly winds will continue over the region. This will continue to bring moisture up over the islands into Saturday. A surface low developing about 1100 miles northwest of Kauai on Saturday will help to bring additional moisture northward, however the low is expected to stay far to the northwest of the islands, so not expecting those showers to impact us.
Sunday should see our winds become southeasterly, and by Monday we expect to see trade winds filtering back into the islands. As the trade winds build back, moisture upstream will be carried in on the trades, bringing showers back to the more typical windward and mauka areas. During the second half of the week, the high pressure responsible for the returning trades is expected to be sinking southward, which will shift our winds to a more southeasterly direction. Will need to monitor future models runs to determine any significant changes in shower .

Aviation

The trough near Kauai continues to bring clouds and showers to Kauai in the southerly flow near the islands. AIRMET Sierra is in effect for Kauai for the resulting mountain obscuration, and that is expected to continue through much of the day. Clouds and showers are possible today over the remaining islands, particularly over Oahu and the islands of Maui County. These clouds and showers could at times produce mountain obscuration or MVFR conditions, which could result in those areas being placed under an AIRMET. Anticipate the Big Island to remain mostly under VFR conditions today.

Marine

A surface trough, near Kauai, will continue to bring scattered to numerous showers to much of the coastal waters today with isolated thunderstorms possible over the western waters. Aside from any gusty winds associated with passing thunderstorms, generally gentle to locally moderate southerly winds will prevail east of the trough. The Small Craft Advisory (SCA) for waters surrounding Kauai and Oahu has been cancelled, as combined seas have lowered below advisory levels (10 ft). By late this weekend, easterly trade winds will gradually build from east to west with the potential for SCA conditions over the windier waters and channels around Maui County and the Big Island. Expect trades to strengthen further early next week as surface high pressure builds to the north.
The current moderate, medium period, north northwesterly swell (340-350 deg) peaked yesterday evening and has been slowly fading since. Thus, the High Surf Advisory (HSA) for north and west facing shores of Niihau, Kauai, Oahu, Molokai, and north facing shores of Maui has been cancelled. However, this north northwest swell will remain elevated today and keep surf just shy of advisory levels through early Saturday. A moderate, medium period, northerly swell is progged to enter the waters late Saturday and may bump surf back up to near advisory levels Saturday night into Sunday. Sunday night into early next week, the swell fades and should allow surf to drop to below seasonal averages.
East facing shores will remain small given the lack of trade winds upstream of the islands, but areas exposed to the north swell will see an uptick through the rest of the week. As trade winds gradually strengthen later this weekend, east facing shores could become rough and choppy Sunday through early next week. Surf along south facing shores will remain small through remain flat to tiny through the weekend into early next week.

Fire weather

Showers will continue, along with light southerly winds and generally high relative humidities. This will keep conditions below critical fire thresholds through the next few days. Longer range forecast show little chance for dangerous fire weather well into next week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov