West Side

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88. Northeast winds 10 to 20 mph increasing to 20 to 25 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly clear. Breezy. Lows 71 to 78. Northeast winds 20 to 25 mph.

Thursday: Mostly sunny. Windy. Highs 79 to 87. Northeast winds 25 to 35 mph.

South Side

Today: Sunny and breezy. Highs around 89. Northeast winds 10 to 25 mph increasing to 20 to 25 mph in the afternoon.

Tonight: Mostly clear. Breezy. Lows 72 to 80. Northeast winds 15 to 25 mph.

Thursday: Mostly sunny. Windy. Highs around 88. Northeast winds 20 to 30 mph with gusts to 55 mph.

North Shore

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 74 near the shore to around 57 near 5000 feet. East winds 20 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Thursday: Windy. 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 66 near 5000 feet. East winds 20 to 30 mph. Chance of rain 40 percent.

Central Maui

Today: Sunny and breezy. Isolated showers in the morning. Highs 82 to 89. Northeast winds 10 to 20 mph increasing to 20 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows around 74. Northeast winds 20 to 25 mph.

Thursday: Mostly sunny. Windy. Highs 81 to 88. Northeast winds 25 to 30 mph.

Upcountry

Today: Windy. Occasional showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 67 at the visitor center to around 62 at the summit. East winds 15 to 20 mph increasing to 20 to 30 mph in the afternoon. Chance of rain near 100 percent.

Tonight: Windy. Partly cloudy with scattered showers. Lows around 55 at the visitor center to around 52 at the summit. East winds 25 to 30 mph with gusts to 50 mph. Chance of rain 50 percent.

Thursday: Mostly sunny in the morning then becoming partly sunny. Windy. Isolated showers. Highs around 65 at the visitor center to around 60 at the summit. East winds 25 to 30 mph with gusts to 50 mph. Chance of rain 20 percent.

East Maui

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 74 near the shore to around 57 near 5000 feet. East winds 20 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Thursday: Windy. 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 66 near 5000 feet. East winds 20 to 30 mph. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 75 to 84. East winds 10 to 20 mph shifting to the northeast 20 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Windy. Lows 68 to 73. Northeast winds 20 to 30 mph.

Thursday: Mostly sunny. Windy. Highs 74 to 84. East winds 25 to 35 mph with gusts to 55 mph.

Kaunakakai

Today: Windy. Mostly sunny with isolated showers. Highs 71 to 90. East winds 20 to 30 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Windy. Lows 63 to 78. East winds 20 to 30 mph with gusts to 50 mph.

Thursday: Mostly sunny. Windy. Highs 70 to 89. East winds 25 to 35 mph with gusts to 55 mph.

Detailed Forecast

Synopsis

The trade winds are slowly edging upwards and are expected to build to strong and gusty levels over the windier spots across Maui County and the Big Island today. Winds will be on the uptick across Kauai and Oahu as well, but not quite as strong as the southern islands. The uptick in winds is in response to Hurricane Lowell, currently about 460 miles east-southeast of Hilo, passes by to our south, and a high pressure system far to the north. Moisture being carried in on the trade winds will focus clouds and showers mostly to the windward and mauka areas, particularly during the overnight through early morning hours each day. The forecast remains uncertain for the upcoming Labor Day weekend due to both Lowell and Karina remaining in the central Pacific over the coming days.

Discussion

A Wind Advisory has been issued for portions of Maui County and the Big Island starting at noon today. The advisory goes through 6 am Friday, but may need to be extended in time and/or expanded to additional areas. Winds were already approaching advisory levels yesterday, and there is good model agreement that winds will increase today. Otherwise not much change to the forecast.
Radar and satellite show an area of clouds and showers continuing to move through the islands from east to west in association with a surface trough. After this trough and its associated moisture moves to the west of the islands later this morning, the pressure gradient between a high far north of the islands, and Hurricane Lowell to the south will tighten. This in turn will lead to the trade winds increasing. Shower activity will return to more typical trade wind weather showers, at least until this weekend.
Hurricane Lowell is about 460 miles east-southeast of Hilo early this morning. The latest forecast track from the National Hurricane Center (NHC) will have Lowell passing a 400 miles or so south of the islands over the next couple of days, before it turns to the north. This northward turn of the system will be determined by the interaction of Lowell with an upper level low the models depict as sinking south towards the islands this weekend. A lot of details on the timing and exact track of the system, coupled with associated impacts, remain to be ironed out. There is uncertainty as to when that northward turn will happen, so we will be continuing to monitor the forecast and make modifications as needed.
Meanwhile, Hurricane Karina is about 1490 miles east of Hilo early this morning, and the latest forecast from the NHC has it moving to the west-northwest through Friday, before lifting further to the north over the weekend. As Karina moves northeast of the islands this weekend and early next week, it will help to disrupt the strong trade wind flow, helping our winds to return initially to more moderate levels. Early next week it could lead to lighter winds.
Due to the uncertainty with the forecast tracks of both Lowell and Karina this far out, the details of the forecast for this upcoming holiday weekend are still being flushed out. In general a general trade wind pattern is in the grids with the possibility of increased shower activity across the state due to moisture reaching the islands from the south from Lowell, and being carried in on the trade wind flow.
Please visit the hurricanes.gov page for the official NHC forecast for Lowell and Karina.

Aviation

The western passage of a weak low level trough is pulling in higher moisture across the islands this morning. This has resulted in tempo IFR and MVFR categories with lowered ceilings and more frequent rain passing across windward-facing terminals. VFR will generally prevail today. Moderate to locally strong trade winds with occasional MVFR decks within brief showers will favor windward exposures and upslope higher terrain. Hurricane Lowell is forecast to pass far south of the island chain the next couple of days. On this westerly track, regional trade winds will remain strong per a tight pressure gradient between the hurricane and high pressure to the far north.
AIRMET Tango remains in effect for moderate low level turbulence south through west downstream of high terrain. AIRMET Tango will likely be in effect for the foreseeable future.

Marine

As a strong surface high persists far north of the Hawaiian Islands and interacts with Hurricane Lowell passing to the south, trade winds will strengthen across the coastal waters to become fresh to locally near gale force. The Small Craft Advisory (SCA) remains in effect for the typically windy waters early this morning and will expand to include all waters from 6 AM HST today through Thursday night. The offshore waters will likely see tropical storm conditions over the far south waters while the core of hurricane force winds remains just outside the area today through Thursday. There is still some uncertainty with the forecast track of Lowell, especially late this weekend into early next week as the cyclone begins to gain latitude, which will have significant impacts on the wind, wave, and surf forecast for the region. Adding to the extended forecast uncertainty will be the approach of Hurricane Karina from the east.
A moderate, long-period south swell will peak later today below advisory levels and hold into Thursday. This swell will then gradually decline through the rest of the week. A small, medium- period south southeast swell from Lowell will fill in through the day before becoming more southerly Thursday through Friday. These combined swells will keep south shore surf elevated near to just below advisory levels. Beyond that point, the surf forecast is highly dependent on the eventual track and intensity of Lowell, which has the potential to be a significant source of south to southwesterly swell through this weekend and into next week.
Trade wind swell energy will keep rough, choppy surf along all east-facing shores through at least the weekend. A small, medium- period east swell from Hurricane Karina began filling in overnight and is expected to gradually build through the week, possibly pushing east shore surf to advisory, or even warning thresholds by this weekend and into next week.

Fire weather

Trade winds will increase today and remain strong and gusty into Friday. Gusts to, or over 50 mph, will be possible in the typical windy areas. Relative humidity values are forecast to remain too high for critical fire criteria to be reached, and fuels are currently rated as not critical. Therefore, the strong winds will not trigger fire weather watches or warnings. The trade inversion is forecast to be 5500 ft to 6500 ft today.

HFO Watches/Warnings/Advisories

Wind Advisory from noon today to 6 AM HST Friday for Big Island North, Big Island South, Big Island Southeast, Kahoolawe, Kipahulu, Kohala, Lanai Leeward, Lanai Mauka, Lanai South, Lanai Windward, Maui Central Valley North, Maui Central Valley South, Maui Leeward West, Maui Windward West, Molokai Leeward South, Molokai North, Molokai Southeast, Molokai West, Molokai Windward, South Haleakala, South Maui/Upcountry, Windward Haleakala.
Small Craft Advisory until 6 AM HST Friday for Big Island Windward Waters, Kaiwi Channel, Kauai Channel, Kauai Leeward Waters, Kauai Northwest Waters, Kauai Windward Waters, Maui County Leeward Waters, Maui County Windward Waters, Oahu Leeward Waters, Oahu Windward Waters.
Small Craft Advisory until 6 AM HST Friday for Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters, Maalaea Bay, Pailolo Channel.

Data Courtesy of NOAA.gov