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.
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.
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.
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.
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.
