Weak winds due to a ridge of high pressure will continue into next week. Stable air and relatively low inversion heights will help keep the state fairly dry through the weekend and into early next week. A front will approach the area in the middle of next week, potentially bringing an increase in rainfall and humidity.
Latest satellite images show mostly clear skies over the region. Radar shows very few light showers, mainly over the eastern parts of the Big Island and Maui.
Weak surface ridging extending in from the northeast will remain over the islands through at least early next week. Both upper level and surface troughing will stay well to our north. This will leave us with weak southeast surface winds through Wednesday. It looks like typical northeast to east trade winds will not be back with us for quite a while. This weak southeast flow will allow for sea and land breeze formation and above-normal cloudiness in leeward areas. Showers will be scarce, with stable inversions down in the 5000 to 6000 ft range. There will most likely be a few light showers, favoring the eastern and southeast side of the highest peaks. Vog from the recent eruption of Kilauea will persist over much of the area in coming days, and we continue to carry this in the forecast with the working of haze.
Latest guidance suggests that the approach of an upper level trough next week will come later than earlier runs, so we now expect it to come near the western end of the state towards the middle of next week. It does not appear that it will reach us, but could lead to increased low level moisture after Tuesday. As always, later runs will shed more light on things.
Light east to southeast winds will be with us for the foreseeable future. Land and sea breezes will continue to bring interior clouds in the afternoons, with few showers expected. No AIRMETs in effect or expected across Hawaii today.
A surface ridge, parked just north of the state, will allow for mainly gentle to moderate east to east-southeast flow across the waters through the end of this week. Winds are forecast to ramp up a bit for the typical windy areas around Maui and the Big Island Friday. Waters located in the lee of the islands will be more sheltered, and thus lighter flow with a nocturnally driven land/sea breeze pattern close to the coasts. Similar conditions will prevail through the weekend as a frontal system stalls north and west of the islands.
The current large long-period northwest swell will peak this evening then gradually decline over the next few days. A reinforcing northwest to north-northwest swell generated by a compact low passing north of the islands today should arrive tonight and could help maintain advisory level surf through parts of the day Friday. The current High Surf Advisory is in effect through early Friday morning for select north and west facing shores, but that may need to be extended depending on this reinforcing swell. With offshore buoy readings staying near or just below 10 feet with the current swell, we have held off on issuing a Small Craft Advisory (SCA) for our local waters exposed to the northwest swell.
Over the next few days, models rapidly deepen a low in the north Pacific, roughly 1,500 to 2,000 nm northwest of Kauai. A significant fetch of gale to storm force winds associated with this low will be pointed down the great circle route towards the island chain and will produce XL surf late this weekend. Long-period forerunners should start arriving around mid-day Saturday, then quickly ramp up Saturday evening into the night. The peak of the event currently appears to be Saturday night into Sunday with the potential for giant surf (40 to 50 feet) along north facing shores Saturday night into Sunday out of the 300-320 degree swell direction. Surf heights will easily exceed High Surf Warning thresholds for select north and west facing shores, in addition to a SCA for rough seas.
Surf along east facing shores will remain small through the weekend due to the lighter winds. Select south facing shores could see some westerly wrap from the extra large northwest swell on Sunday.
High Surf Advisory until 4 AM HST Friday for Niihau-Kauai Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kauai North-Molokai Windward-Molokai North-Molokai West-Maui Central Valley North-Windward Haleakala.
