Marine Weather and Tide Forecast for Discovery Harbour, HI

DISCUSSION

A weak surface trough between Oahu and Molokai presents as a narrow corridor of enhanced shower activity and as a boundary between NE trades and building easterlies. With no meaningful mid/upper level support, this trough will advance westward and bring a brief period of enhanced showers to Windward Kauai late this evening before gradually damping out during the next 12 hours or so. An upper low positioned well southwest of the islands will be of little consequence other than serving as a source for abundant high clouds to drift across area skies through Friday. Stronger upper-level southwesterlies shift west of the area on Friday night bringing a significant reduction in coverage of high clouds by Saturday.

Moderate trades continue through at least this weekend as the core of the trade wind belt remains suppressed south of the islands courtesy of persistent height falls across the northern and central Pacific. The long range guidance indicates potential for the return of breezy trades by the middle of next week, but any return of stronger trades is likely to be brief/transient and come to an end as the next round of mid-latitude height falls commences north of the area.

AVIATION

Moderate trades will continue over the next couple of days.
Clouds and isolated to scattered showers will typically favor windward and mountain areas, particularly overnight, and bring brief MVFR conditions in heavier showers. In this lighter wind pattern, sea breezes will also bring afternoon cloud build ups and isolated showers to select leeward interior areas that will then clear out overnight with land breezes. In addition, shower development may be enhanced over the next 12 to 24 hours as a surface trough passes through. Overall, besides in brief heavier showers, VFR conditions should prevail across the island chain.

An upper level jet streak between the main Hawaiian Islands and an upper level low to the west is providing some light to moderate upper level turbulence over the state this afternoon. As such, AIRMET Tango has been issued. This turbulence should weaken and move to the west of the state as the jet streak gradually heads off in that direction.

MARINE

Far north of the islands, a weak cold front will drop southward over the next few days, displacing surface high pressure to the north-northwest and weakening the pressure gradient over the islands. This will allow local trade winds to ease into the gentle to locally moderate range through the rest of this week and this weekend. Small Craft Advisory conditions may develop early next week as a high rebuilds north of the state and moderate to locally strong trade winds return.

The north-northwest swell that has been moving through the islands for the past couple of days continues to slowly fade. While some small surf remains on north-facing shores, bouys have generally been trending down and north shore surf is expected to hover around the current levels through Friday. A reinforcing bump in north shore surf will be possible late Friday night or Saturday morning as a small short to medium period north swell fills into the region. However, the next significant north-northwesterly (340 degree) swell that could produce advisory-level surf along north facing shores is poised to arrive Sunday afternoon. This swell will peak Monday through Monday night, then slowly decline through rest of next week.

A small, long period south swell will reinforce the current background south swell tonight and continue small south shore surf through Friday. Surf along west-facing shores will continue to be influenced by a mixture of both north northwest and south swells.
Thus, expect western exposures to remain slightly elevated as well. East-facing shore chop will be lower than normal over the next several days as trade wind flow remains relatively weak locally and upstream.

HFO WATCHES/WARNINGS/ADVISORIES
None.