textproduct: Honolulu

SYNOPSIS

A slightly unstable and somewhat wet trade wind flow will continue into Monday. An increasingly stable, moderate to breezy trade wind flow will develop Tuesday and Wednesday and will persist into next weekend.

DISCUSSION

Scattered heavy showers over windward areas diminished overnight as the upper level low that lingered over the area during the past couple of days lifted away to the northeast. A handful of windward stations picked up 1 to 2 inches of rainfall, mainly before midnight. Little rainfall managed to make it leeward areas since the local pressure gradient and resulting trade winds remained somewhat weak due to the effects of the upper low.

Moderate easterly winds and a somewhat wet pattern of mainly windward and mauka showers is expected over the next couple of days. The GFS and ECMWF show moisture remaining slightly elevated and dew points hanging on in the upper 60s to lower 70s, allowing the humid trade wind flow to continue to produce showers over windward areas. Broad troughing aloft will maintain some instability, which could still trigger a briefly heavy shower, mainly over the heated leeward slopes of the Big Island and Maui during the afternoon hours.

Increased stability and stronger trade winds are due late Tuesday or Wednesday. Expect a typical pattern of mainly windward rainfall and mostly dry conditions leeward into next weekend.

AVIATION

Flight weather conditions will improve today as the upper level disturbance continues to drift eastward away from the Hawaiian Islands. Brief showers linger in the forecast mainly over windward and mountain areas of each island.

AIRMET Sierra remains in effect for mountain obscuration for the east section of Maui.

MARINE

Moderate to locally fresh easterly trades have returned. An upper level-low that plagued the state has moved off to the northeast, increasing stability and decreasing showers.

A small, medium-period north northwest (320-330 degree) swell will continue to decline through tonight, with surf along north- facing shores following suit. A medium-period north-northwest reinforcement may provide another small bump in surf along north- facing shores by early Monday morning, followed by another small reinforcing swell on Tuesday.

Surf along west-facing shores will remain nearly steady through the rest of the weekend as the northwest swell influence gradually declines, but a new, long-period south southwest swell fills in.

A mix of small, medium- to long-period south swells will maintain small surf along south-facing shores for the next several days. The long-period south-southwest swell described above will increase surf along south-facing shores through today. Additional small, medium- to long-period south swell reinforcements will arrive through midweek.

Moderate to fresh trades will maintain rough and choppy surf along east-facing shores for the next several days.

Tides will peak around 2.5 to 3.0 ft MLLW today. Minor overwash of low lying coastal areas will be possible during times of high tide.

HFO WATCHES/WARNINGS/ADVISORIES

None.