Marine Weather and Tide Forecast for Lahaina, HI

DISCUSSION
The main shower band has drifted eastward from the previous forecast and is now located over Maui County and the Alenuihaha Channel. Rainfall rates from these showers have been producing below a tenth of an inch per hour. The subtropical jet, currently located just north of the Hawaiian Islands and drifting southward, will help steer these intermittent shower bands over the region for the next several days. Cloud coverage will also be maintained through much of the week, ensuring dewpoints remain high in the upper-60s, leading to noticeably humid conditions. With the lighter surface winds in the forecast, initially from the southeast before becoming variable, any diurnal heating will be enough to trigger land and sea breeze activity. This may bring leeward and interior showers throughout the day, and partial clearing overnight for most of the islands. Otherwise, these weak, intermittent shower bands will persist as they ride the subtropical jet following the southwesterly flow aloft.

Toward the latter half of the week, the surface low pressure system, once anchored just north of the islands, will finally dislodge and move northeastward opening the doors for high pressure to quickly build in its place. Light trades attempt to develop in response, however, latest model guidance depicts an upper-level trough digging down into the vicinity of the state from the northwest. While not overly impressive, nor super impactful currently, it is expected to limit the strength of the trades. That being said, it is worth keeping an eye on the evolution of the upper-level trough to determine if it enhances the ongoing shower activity (especially with the lingering moisture-laden airmass across the state), or if it is simply passing through.



AVIATION
Low cigs and isol SHRA will continue across the islands. MVFR conds possible but VFR should prevail. Winds will generally be driven by land-sea breezes. The forecast generally trends back toward trades tomorrow into Thursday.

No AIRMETs in effect.



MARINE
A weak surface trough will reside just west of the state through Thursday. This will allow for gentle southeast flow across the waters and locally moderate easterly flow in the typical windy channels surrounding Maui and the Big Island. Surface high pressure building far north of the region will help tighten the pressure gradient and bring moderate to locally fresh easterly trades across the Hawaiian coastal waters Friday into this weekend.

A small, short-period, northwest swell will continue to slowly diminish through the rest of the week and into the weekend.

A small, medium-period, south swell has arrived at the near shore buoys and should provide a boost to surf along south facing shores through late week before gradually subsiding into the weekend.

Surf along east facing shores will remain below seasonal average with lighter than average trade winds near and upstream of the islands forecast through late this week. A slight bump up in surf may occur Friday into this weekend with the increase of easterly flow.



HFO WATCHES/WARNINGS/ADVISORIES
None.