textproduct: Honolulu

SYNOPSIS

A surface ridge building north of the islands will allow moderate trade winds to return to the islands Thursday. Rainfall will be limited into the weekend due to an upper level ridge over the islands. However low level moisture riding in on the trades will bring more typical windward and mauka showers by the end of the weekend.

DISCUSSION

No updates to the forecast this evening, and not expecting any significant changes with the morning package.

A low pressure system more than 700 miles northeast of the islands, combined with a surface trough about 600 miles to the north, are helping to maintain the lighter winds over the region this evening. Clouds are clearing out in the light wind pattern over the islands, and satellite shows few clouds near the islands.

The low and trough are expected to dissipate over the next 24 hours, and that will allow a surface ridge to build back in north of the islands. This in turn will allow moderate trade winds to build back in at the surface. The global models agree on mid level ridging over the region which will help to maintain a stable airmass, thereby limiting shower activity over the next few days.

The global models are in good agreement that moisture from the above mentioned low will get caught up in the trade wind flow over the weekend, and late in the weekend, make its way into the islands. This will help us return to a more typical trade wind weather pattern with some showers over the windward and mauka areas, along with the clouds and showers that form over the Kona slopes during the afternoon.

AVIATION

Northeasterly trade winds will fill in tonight becoming moderate tomorrow and focus most showers over windward and mountain areas. VFR conditions will prevail with brief MVFR conditions any in showers.

No AIRMETs in effect.

MARINE

Trade winds will be making a come back through Thursday in response to an upper ridge building in west of the islands. The associated surface high will travel across to the north of the waters and be northeast of the state by early next week. This will produce a tight enough Central Pacific pressure gradient to maintain moderate to locally fresh trades Thursday and Friday. Trades will persist through the weekend as another high passes north of the state. Brief periods of locally strong winds will be possible this weekend over the windier areas surrounding Maui County and Big Island.

A moderate size, medium period northwest swell that peaked early today will gradually decline the next few days. A pair of North Pacific gale lows will send a series of small north to northwest swells down into the local waters from Friday night through the first half of next week. These swells will likely maintain near to slightly below average north-facing shore surf into next week.

A moderate size, medium period north northeast swell that quickly filled in last night and peaked during the day introduced advisory level surf along many northeast to eastern exposures, as well as lifting surf to above average heights along some select western shores in Maui and Big Island. This swell will slowly decline through the remainder of the week. Moderate to fresh trades this weekend will support near seasonal average east-facing shore wind wave surf.

Small background energy from the west will continue to linger the next few days and fade out this weekend. A small southwest bump from very faded Tasman Sea energy is expected to arrive this weekend. No significant south swells are expected through the first half of next week.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Advisory until 6 AM HST Thursday for Big Island East- Big Island North-Big Island Southeast-Kipahulu-Koolau Windward- Molokai Southeast-Molokai Windward-Olomana-Windward Haleakala.