textproduct: Honolulu

SYNOPSIS

Fairly steady weather until Tuesday, with light southeast winds and mostly dry conditions. Sea-breezes during the day and land- breezes during the night will be present, leading to a little more cloudiness in leeward areas than during a trade wind setup. A cold front is forecast to get to Niihau and Kauai Wednesday, and possibly as far east as Oahu. This will bring northerly winds and an increase in precipitation, with trades returning Thursday into next weekend.

DISCUSSION

Satellite and radar show mostly clear skies with a very few showers, mostly over the ocean, this morning. Dewpoints were a little lower than normal, with mid-60s noted at Honolulu and upper 50s at Kahului. A ridge of high pressure at the surface extends across the state this morning, and this feature will remain relatively stable through Monday.

Early next week, an initial cold front will approach the state but stall to our northwest. This front will quickly be followed by a second front, driven by a strong upper trough approaching on Tuesday. Global models continue to indicate that this front could move through Niihau and Kauai early Wednesday, possibly reaching Oahu later Wednesday. Behind the front, breezy north to northeast winds will build into the region and rainfall chances will increase significantly. To the east of the front, some moisture increase is expected, but forcing for showers will not be as strong and therefore the increase in precipitation will be less impactful. There remains a good deal of uncertainty in the frontal position, particularly whether or not it will make it as far east as Oahu, and details will become more clear as the time approaches.

Regardless of how far east the front moves, it is expected to quickly recede back to the west and north Thursday. Trade winds will build in as a new surface high develops to the north and northeast. This trade wind pattern should be with us through at least next weekend.

AVIATION

Light southeast winds will continue with prevailing VFR conditions expected at most sites.

No airmets in effect.

MARINE

A high pressure ridge will remain locked in place over the Hawaiian Islands into early next week. Expect light to moderate southeast winds, with near shore sea breezes each day. An approaching cold front will stall just northwest of Kauai on Sunday, and a second stronger cold front may move into the western islands on Wednesday. If this occurs, moderate to breezy NW to N winds will follow in the wake of the front, while continuing light to moderate E to SE winds will develop just E of the frontal zone. An XL northwest swell will swiftly build into Hawaiian waters today, peaking Sunday, and slowly declining on Monday. Combined seas for Hawaiian Coastal Waters exposed to WNW swell will rise above Small Craft Advisory levels (above 10 feet) through early next week.

Surf across N and W facing shores will remain fairly small this morning before an XL WNW swell swiftly builds into the region from this afternoon to evening. This swell will bring dangerous surf heights ranging from 25 to 45 feet along most N and W facing shores with larger waves over select outer reefs. This swell will peak Sunday morning, and slowly decline on Monday. A High Surf Warning remains in effect for the N and W facing shores of the smaller islands. An expansion to the warning was issued with this mornings surf forecast along the west facing shores of the Big Island, as warning level surf will build in later tonight. Another moderate to large NW swell is possible for the second half of next week from another potential Gale to Storm force low that long range weather models are spinning up in the NW Pacific.

East shore surf will remain small through the weekend due to weak winds. Select south facing shores could experience westerly wrap from this weekend's large WNW swell passage.

FIRE WEATHER

Dry conditions are expected this weekend into early next week, with relative humidity values falling into the low- to mid-40 percent range for some leeward locations each afternoon Saturday through Monday. However, weak winds will prevent critical fire weather thresholds from being reached.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Warning from noon today to noon HST Monday for Niihau- Kauai Leeward-Waianae Coast-Oahu North Shore-Maui Windward West- Kauai North-Molokai Windward-Molokai North-Molokai West-Maui Central Valley North-Windward Haleakala.

High Surf Warning from 6 PM this evening to noon HST Monday for Kona-Kohala.

Small Craft Advisory from noon today to noon HST Monday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-Oahu Windward Waters-Kaiwi Channel-Maui County Windward Waters-Big Island Windward Waters.