textproduct: Honolulu

SYNOPSIS

An unstable and somewhat wet trade wind pattern will continue through Tuesday night, with brief downpours possible. From Wednesday into early next week, an area of high pressure north of the islands will push drier air the region and strengthen winds. The result will be a moderate to breezy trade wind pattern.

DISCUSSION

Showers across windward and mauka areas, along with the Kona Districts on Big Island, were noted on radar this afternoon. Some showers have been producing moderate to briefly heavy rain, and this has resulted in the issuance of flood advisories on Kauai and on Big Island. These showers will trend down around sunset. Winds were averaging 10 to 20 mph with gusts 20 to 30 mph.

Conditions remain on the humid side this afternoon as we await drier air that should arrive from Tuesday night into Wednesday night. Until that arrives, we will continue to see rather wet trades, meaning we will continue to have the chance for moderate to briefly heavy rain from showers. From late Wednesday onward, we will see noticeably lower PW values (down around 1 inch) going all the way into next week. Aloft, an upper level ridge will become established to our north, even as weak troughing will extend off the southwest coast of the mainland toward Hawaii. This troughing will have little to no impact on our surface weather, as the upper ridging will help keep relatively dry trades established over the region. Dewpoints will fall several degrees as the dry air comes in, allowing a little more cooling overnight for wind-sheltered areas.

AVIATION

Moderate to locally breezy trades expected hold for the next couple days. Low cigs and SHRA will primarily impact windward and mauka locations with some limited spillover to leeward areas. Kona slopes of the Big Island will see low cigs and SHRA in the afternoon with some clearing overnight. MVFR conds possible in heavier SHRA, otherwise VFR prevails.

AIRMET Sierra is in effect for mtn obsc for windward Kauai, Oahu, Maui and the entire area of the Big Island.

Weak inversion heights are have kept moderate low level turbulence from developing this afternoon. Thus will hold off issuing AIRMET TANGO, but will continue to monitor over the next day or so as the atmosphere become more stable.

MARINE

A surface high centered far northeast of the state will generate moderate to locally strong trades over the next few days. This anchored high will strengthen and expand during the second half of the week and will cause the trade winds to strengthen to widespread strong speeds with near gales over the windier zones around Maui County and the Big Island. A Small Craft Advisory (SCA) is currently in effect for the windier zones around Maui County and the Big Island. The SCA will expand in area later this week as the trades strengthen.

A small size, short to medium period north northwest is expected on Tuesday. A Gale low developing in the North Pacific on Tuesday should send a small northwest to north northwest bump over the weekend.

A series of small long-period south-southwest swells will provide surf near the summer average along south facing shores throughout the week. Strengthening trades later this week will bring an increase of short-period energy and will bring elevated surf along east facing shores by Thursday or Friday.

Water levels peaking between 2.5 to 3.0 ft MLLW during today's high tides may result in some minor overwash within low lying coastal areas this afternoon.

HFO WATCHES/WARNINGS/ADVISORIES

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