A high pressure system will linger north to northeast of the Hawaiian Islands through the middle of next week, producing moderate to breezy trades with minor fluctuations in speed. Brief increases in showers, most noticeable tonight and Sunday night, will give way to drier trades for most of next week. There is still significant uncertainty in next weekend's weather.
Radar and satellite show isolated showers across the windward areas of most islands, along with the usual trade wind pattern of mostly cloudy skies windward and partly cloudy to mostly sunny leeward. Winds were mainly out of the east or northeast, averaging 10 to 20 mph, with gusts to near 30 mph in a few places.
An evolving but basically persistent surface high pressure system to out north (sometimes northeast) will be with us for the next week. This should keep the trades blowing at moderate to breezy levels. There remains some uncertainty concerning the possible development of a surface low near the islands Friday, but ensembles are not giving a clear indication of what, if anything, might form.
In the meantime, two brief periods of enhanced showers appear to be on the way - one tonight and another Sunday night. There are no indications that heavy rain or flooding is likely. After that, we are in for a period of relatively dry trades as we await anything that might develop late in the week. Winds should remain strong enough to keep any showers moving fast enough to occasionally bleed over to leeward areas, but any rainfall amounts there will be light.
VA SIGMET November in effect for Mt. Kilauea eruption in the south-central portions of Big Island. See VA SIGMET November for more detailed information. Since the eruption has subsided, and based on overall wind trajectory, no ash threat near terminals. SIGMET November is likely to be cancelled within the next 6 hours.
Otherwise, breezy trades will continue with isolated MVFR ceilings and visibility in any passing shower, mainly windward and mountain areas.
AIRMET Sierra may be needed tonight to account for mountain obscuration development in windward areas.
AIRMET Tango will continue into tomorrow for tempo moderate turbulence downwind of terrain below 9000 ft.
High pressure north of the islands maintains fresh to strong trades well into next week. The Small Craft Advisory (SCA) has been expanded in coverage to include Oahu and Kauai waters as trades are forecast to strengthen modestly tonight and tomorrow.
A mix of short period NNW swell which peaked at the outer buoys early this morning, and declining mid- long period swell (12 to 16 seconds) will keep small surf in place through tomorrow. Both of these swells drop off by Monday, allowing surf to drop to tiny levels through much of the week before a small northwest arrives towards the end of the week.
A mid to long period south-southwest swell (15 seconds) will keep above average surf in place tonight over south shores, then decline tomorrow and remain small through much of the week with background south swells. A small long period swell is possible next weekend.
Rough trade wind swell will produce above average surf for E shores through Tuesday before declining with weakening trades mid- week. Expect some wrap of NNW swell for exposed shorelines through tonight.
Small Craft Advisory until 6 AM HST Monday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Kaiwi Channel-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters-Maalaea Bay-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters-Pailolo Channel.
