A weak surface ridge will maintain light winds and rather dry conditions over much of the state tonight as an advancing front produces increased clouds and showers on Kauai. The front will bring a period of trade winds and showers to mainly windward Kauai and Oahu on Monday and may reach as far as Maui. The front will dissipate and lift northward Monday night as winds shift out of the southeast. A surface ridge will settle over the islands Tuesday and produce a somewhat dry land and sea breeze pattern through Thursday. Another weak front may affect portions of the state Thursday night into Saturday.
A approaching weak front from the northwest will bring an increase of showers as it reaches Kauai tonight, Oahu by daybreak, and stall out near Maui County Monday. Light winds will prevail over most islands but the front will bring an increase of showers and breezy easterly trade winds on Monday. MVFR ceilings and visibility associated with the cold front will linger from Kauai through Monday County through Monday afternoon. Winds look to weaken and veer as light to moderate east to southeast winds will fill in by Monday night.
No AIRMETs are currently in effect, however AIRMET Sierra will likely go into effect later tonight into tomorrow due to the approaching front.
Fresh northerly winds associated with a front settling southward into the region will gradually spread across the Kauai waters late tonight, then expand into the waters north of Oahu by daybreak Monday. Locally stronger terrain-driven winds along the leeward and windward coasts of Kauai may briefly approach or reach Small Craft Advisory levels during this period. The latest guidance shows this boundary stalling and gradually weakening as it lingers from east to west across the smaller islands through Monday. High pressure building north of the area in its wake will allow northerly winds to veer easterly on Monday. For Maui County and the Big Island waters, light winds will prevail overnight, then gradually shift out of the east and increase into the light to moderate range through the day Monday.
The progressive pattern across the region continues thereafter, with another front approaching by midweek. As the ridge axis shifts southward over the islands, winds will veer to the south to southeast Monday night through Tuesday. This front could reach the Kauai waters late in the week.
Surf along exposed north- and west-facing shores will remain small through Monday as the medium-period northwest swell that arrived Sunday continues to ease. Combined with fresh northeast breezes, this will lead to rough and choppy conditions along northern exposures of Kauai, and potentially Oahu early Monday depending on how far south the boundary settles.
A fresh, medium-period northwest swell generated by a broad storm-force low tracking eastward near the Aleutians will arrive Monday night, then shift out of the north-northwest and peak Tuesday night. Surf may approach advisory levels before gradually easing Wednesday into Thursday.
Another larger northwest swell is expected later this week as a broad and complex low evolves over the far northwest Pacific. This swell will begin building down the island chain Thursday and could become a long-duration event, with a peak centered around the Friday through Saturday time frame. Some uncertainty remains regarding the magnitude and timing, as the ECMWF and GFS continue to depict differences in the evolution of this system.
Surf along east-facing shores will briefly trend upward as the trades return Monday, with the highest surf expected along Kauai and Oahu. This will be short-period and choppy, driven primarily by locally generated wind waves, and should be short-lived. A downward trend is anticipated by Tuesday as winds shift toward the south and upstream trade flow remains absent.
Surf along south-facing shores may also see a slight uptick by Tuesday as a small, background long-period south swell arrives. This source is expected to ease by midweek.
None.
