textproduct: Honolulu

SYNOPSIS

A dry, stable breezy trade wind pattern will persist through the forecast period. Light to moderate showers will primarily focus along windward and mauka locations mainly during the overnight evening and overnight hours. Showers will become limited over the weekend as a drier airmass moves over the state. Elsewhere, expect mostly sunny days and clear cool nights.

DISCUSSION

Visible satellite imagery show scattered clouds with embedded showers over windward areas and along the Kona coast of the Big Island where a seabreeze has set up. Showers have been mainly light with just .01 to .10 of an inch of rainfall reported in the past hour for the wetter locations. Leeward areas have been mostly sunny with a few clouds and light showers spilling over at times. Latest high resolution model guidance continues to show a slight uptick in showers as a shallow band of clouds and embedded showers moves over Kauai rest of this afternoon, then over Oahu and portions of Maui County this evening into early Friday morning. Elsewhere mostly clear skies overnight will lead to cooler overnight temperatures. Showers will remain mostly light with modest accumulations being confined mainly to windward and mauka areas given the strong inversion heights around 6 to 7 kft. Breezy northeasterly winds will hold through Friday as a surface high remains northwest of state and a low remains northeast.

This pattern of mostly sunny days and cool nights will continue through the weekend. A weak front marked by another band of shallow clouds with embedded light showers is expected to arrive Friday night and will push through the state into Saturday with and area of moisture diminishing around windward Big Island through the day Saturday. Moisture availability will be less than tonight so again expecting modest precipitation totals and limited low level cloud cover with a few high clouds streaming overhead. Temperatures will be notably cooler behind this front and dewpoints will drop in the mid to upper 50's making for a cooler than normal weekend. Breezy northeasterly trades will become locally windy Saturday into Sunday as the aforementioned high strengthens and the low deepens and remains north of the state into early next week.

By middle of next week the low will have weakened and shifted far northeast of the state allowing the high pressure system to shift north of the state. Trades will become more easterly and ease to more typical breezy speeds. Clouds and showers will continue to be mostly confide to windward and mauka areas with the best chance of rainfall, if any, during the overnight and early morning hours.

AVIATION

Breezy and stable trades deliver showers to windward and mauka sections of Kauai and Oahu tonight with lesser shower coverage elsewhere. Pockets of MVFR possible with this activity. VFR leeward. Winds weaken slightly by tomorrow.

No AIRMETs in effect. AIRMET Sierra may be needed for Windward Kauai and/or Oahu overnight.

MARINE

A low pressure system northeast of the islands and a high pressure system to the far northwest of the Hawaii region will keep northeasterly trade winds in the forecast through the rest of the week. Wind speeds will continue to ease through Friday before a cold front ushers in fresh to strong northeasterly trade winds. Small Craft Advisory conditions are expected to return from Saturday into the first half of next week as high pressure builds north of the state.

A combination of small medium-period northwest swells, one of which is peaking today (310-320 degrees) and the other arriving on Friday (320-330 degrees), will supply small surf along north- facing shores through Saturday. These swells will gradually fade through the weekend.

For east facing shores, short-period wind wave energy from northeasterly trade winds will gradually fade through Friday, then build into the weekend.

A large short- to medium-period north-northeast (010-020 degrees) swell will build into the region Saturday night through Monday, likely bringing advisory-level surf to north- and east-facing shores late this weekend into early next week.

Along south-facing shores, small background pulses will keep surf heights above flat conditions through early next week.

HFO WATCHES/WARNINGS/ADVISORIES

None.