textproduct: Honolulu

SYNOPSIS

Moderate to locally breezy trade winds will continue through the weekend. Bands of low clouds and showers will be carried in on the trades, focused primarily over windward and mauka areas during the overnight and early morning hours. An enhanced area of moisture is expected to reach the islands Tuesday night through Wednesday, bringing more widespread showers. Humidity levels will rise, bringing muggier conditions across the island chain through the middle of this week. Additional areas of increased low level moisture are possible this weekend.

SHORT TERM UPDATE

Winds were increased for the typically windy coastal water zones around Maui County and the Big Island through Wednesday.

DISCUSSION

Satellite shows partly to mostly cloudy skies, with radar only picking up on isolated light showers as of 9 AM HST. The few showers detected by radar were mainly over windward areas of Big Island and Maui. Clouds were primarily low level trade wind cumulus moving in from the east, with a few high-level cirrus associated with the subtropical jet moving in from the west- southwest. Winds were averaging 5 to 15 mph sustained, with gusts generally 15 to 25 mph.

High pressure will remain far north of the state (centered around 40N) for the coming week as it slowly drifts west. Moderate to breezy trade winds will continue through the period, with showers mainly windward and mauka, and more numerous at night.

One significant area of increased low level moisture will move in from the east tonight and Wednesday, spreading more numerous showers to windward and mauka areas, and increasing the chance for noticeable spillover to leeward areas. Brief heavy rain is possible, but the risk for flooding is low. Surface dewpoints will increase into the lower 70s by tonight as this moist area moves through, then drop back into the mid to upper 60s from Wednesday night into the weekend.

AVIATION

A brief break between passing low level troughs will produce mostly VFR conditions across the Hawaiian Islands through this afternoon. The next trough, slightly weaker than the last system, moves westward through the islands tonight through Wednesday. Expect increasing shower trends with brief periods of MVFR conditions and mountain obscurations, mainly along windward mountain areas.

No AIRMETs are currently in effect. AIRMET Sierra for mountain obscurations will likely return tonight across select windward areas as the trough moves through.

MARINE

Surface high pressure far north northeast of the islands will slowly drift west through the forecast period keeping moderate to locally strong trade winds through Wednesday before declining slightly through the rest of the forecast period. The Small Craft Advisory (SCA) has been extended through Wednesday afternoon for the windier waters and channels around Maui County and the Big Island.

The small medium period south swell will keep surf heights elevated along south facing shores today before declining Wednesday. A series of small medium to long period south southwesterly swells are expected Thursday through the weekend. Surf along east facing shores will remain rough and choppy and increase Wednesday as trade winds increase. Surf along north facing shores will remain flat to tiny through the forecast period.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory until 6 PM HST Wednesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.