Breezy trade winds are expected to become strong and gusty across the state beginning Wednesday. Winds are expected to be strongest across parts of the Big Island and Maui. 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. Hurricane Lowell is about 480 miles east-southeast of Hilo this evening and is expected to pass south of the state over the next several days. 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.
Satellite and radar show an area of clouds and showers moving over the windward sides of the Big Island and Maui this evening. This moisture is associated with a surface trough moving to the west. Winds have been on the uptick, in part due to the pressure gradient over the islands between a high far to our north, Hurricane Lowell to our south, and the surface trough moving through the islands.
Winds are expected to increase further on Wednesday, and remain strong and gusty into Friday, due to the tightening of the pressure gradient over the islands between the high far to the north and Lowell to the south. Hurricane Karina is about 1550 miles east of Hilo this evening, and the latest forecast from the National Hurricane Center (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. Meanwhile, the latest forecast for Lowell from the NHC will have the system moving generally moving to the west through Friday, before a northward motion takes over. This northward pull 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, couple with associated impacts, remain to be ironed out. That being said, an increasing number of models have been indicating that a northward turn is to be expected, so stay turned for updates over the coming days.
As mentioned above strong and gusty winds are expected Wednesday into Friday. Advisory level winds are quite possible in the windiest areas. Will be monitoring winds tonight and the latest model runs to determine if an advisory should be posted as part of the morning package. After the above mentioned trough moves through the islands tonight, expect shower activity to go back to more typical showers focused over the windward and mauka areas Thursday and Friday. However as the winds increase, some of those showers could be blown to leeward areas.
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.
Prevailing VFR. Moderate to locally strong trade winds with occasional MVFR decks and visibilities in brief showers that will favor windward exposures and upslope higher terrain. Hurricane Lowell is forecast to pass far south of the island chain the next few days. On this track, regional trade winds will remain strong as a result of a tight pressure gradient between Hurricane Lowell 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.
There is the potential for the lowering of overnight decks to under 3,000 ft within upper elevations. Conditions will be monitored for a potential late evening or early morning AIRMET Sierra for Big Island and Maui County mountain obscuration.
A strong surface high will remain nearly stationary far north of the Hawaiian Islands through the rest of this week, keeping fresh to locally strong trade winds in place through at least Wednesday. A Small Craft Advisory (SCA) remains in effect for the typically windy waters. The SCA will likely need to be expanded as trade winds gradually strengthen across the state to become strong to possibly gale force late Wednesday through Thursday as Hurricane Lowell passes far south. The offshore waters will likely see tropical storm conditions over the far south waters as the core of hurricane force winds remains just outside the area Wednesday into 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 continue to fill in overnight and peak Wednesday. Surf along south facing shores should peak below advisory thresholds. This swell will then gradually decline through the rest of the week. A small, medium- period south southeast swell from Lowell will fill in overnight through Wednesday 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 depending on how sharply and quickly the cyclone turns to the north.
Trade wind swell energy will keep rough, choppy surf along all east-facing shores through the coming week. Tonight, a small, medium- period east swell arrives from Hurricane Karina that will build through the week and could push east shore surf to advisory thresholds by this weekend and into next week.
Small Craft Advisory until 6 PM HST Wednesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.
