West Kaua’i

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 67 to 73 near the shore to around 60 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 40 percent.

Veterans Day: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 83 to 88 near the shore to around 72 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 40 percent.

Tuesday Night: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 68 to 73 near the shore to around 60 above 3000 feet. East winds up to 20 mph. Gusts up to 40 mph in the evening. Chance of rain 40 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71. Northeast winds 10 to 25 mph. Chance of rain 50 percent.

Veterans Day: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 86. Northeast winds 10 to 25 mph. Chance of rain 70 percent.

Tuesday Night: Breezy. Mostly cloudy with scattered showers. Lows around 72. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Breezy. Mostly cloudy with numerous showers. Lows 62 to 68 in the valleys to around 57 above 4000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Veterans Day: Windy. Mostly cloudy with numerous showers. Highs 70 to 78 in the valleys to around 62 above 4000 feet. Northeast winds 10 to 30 mph. Gusts up to 50 mph in the afternoon. Chance of rain 70 percent.

Tuesday Night: Mostly cloudy. Windy. Numerous showers in the evening, then scattered showers after midnight. Lows 62 to 68 in the valleys to around 58 above 4000 feet. Northeast winds 10 to 30 mph with gusts to 50 mph. Chance of rain 70 percent.

North Kaua’i

Tonight: Breezy. Mostly cloudy with numerous showers. Lows 63 to 72. East winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain 70 percent.

Veterans Day: Breezy. Partly sunny with scattered showers. Highs 73 to 85. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tuesday Night: Breezy. Mostly cloudy with scattered showers. Lows 64 to 72. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Lows 63 to 75. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Veterans Day: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 83. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Tuesday Night: Breezy. Mostly cloudy with scattered showers. Lows 63 to 75. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy to locally strong trade winds will continue this week, becoming even stronger by mid-week, as strong high pressure builds north of the islands. Clouds and showers will remain focused over windward and mauka areas.

Discussion

The latest surface analysis shows a 1031 mb high far north of the Hawaiian Islands this afternoon. This is resulting in breezy to strong trade winds blowing across the islands, with some of the windier areas on the Big Island and Maui briefly exceeding wind advisory criteria. Trades are expected to become even stronger by Wednesday as the high is forecasted to build to around 1035 mb. Confidence that more widespread areas will exceed wind advisory criteria on Wednesday is increasing as this morning's ASCAT pass matched well with this morning's model guidance…stay tuned for further updates. Winds will weaken to moderate to breezy later this week as the high weakens and moves northeast of the region.
Radar and satellite imagery continues to show clouds and passing showers focused over windward and mauka areas this afternoon. CIMSS PWATs show a slightly drier air mass over and upstream of the area so not expecting a lot of showers across the region tonight. Guidance continues to suggest an uptick in shower activity on Wednesday as an area of moisture associated with a dissipating front gets embedded in the trade wind flow. Expect windward and mauka showers to continue through the rest of the week.
A slightly drier air mass will keep dew points in the low to mid 60s through Tuesday making things feel cooler than normal. Relative humidity may briefly fall below 50 percent on Tuesday afternoon for isolated leeward areas, particularly across leeward Big Island. Additional areas of moisture moving into the state later this week will allow dew points to increase to the upper 60s to low 70s.

Aviation

Breezy trade winds are expected to continue tonight and into tomorrow. Embedded clouds and showers in the trades will bring MVFR conditions to windward and mountain areas. Otherwise, VFR conditions are expected.
AIRMET Sierra is in effect for TEMPO mountain obscurations from Oahu to Molokai. Conditions are expected to remain at least through the evening as clouds and showers continue to impact windward mountainous areas.
AIRMET Tango remains in effect for mechanical turbulence to the lee of the mountains of all islands due to the breezy trade winds. This is expected to continue through tomorrow.

Marine

Fresh to at times near gale trade winds will persist into Thursday. A 1031 mb high centered about 750 nm north of the islands is driving the strong trades. This feature will consolidate with another, stronger surface high moving in from the northwest during the next 24 hours and will produce winds at current or slightly stronger levels Tuesday night through at least Wednesday night. The Small Craft Advisory (SCA) covering all Hawaiian waters has been extended through Wednesday night. The high will drift eastward and weaken on Thursday and Friday, leading to a gradual decline in the trade winds. The SCA may be needed for all waters during the day Thursday but should be trimmed back to the typically windy waters around the Big Island and Maui by Friday. Moderate to fresh trades are expected this weekend.
The combination of a medium period north to north-northeast (010-020 deg) swell and a short period north-northeast to northeast (020-040 deg) swell will produce large and rough surf above High Surf Advisory (HSA) levels along north and east shores through Tuesday and will contribute to the need for an SCA due to elevated seas above 10 feet. The north to north-northeast swell is likely producing surges at north facing harbors, mainly at Hilo and Kahului. A Marine Weather Statement highlighting this impact has been extended through Tuesday. The north to north-northeast swell will decline late Tuesday, and even as a long period northwest swell builds in on Wednesday, north shore surf is expected to be below the HSA threshold. The northwest swell will lower through Friday, followed by another small to moderate northwest swell Sunday.
As the current north swell fades late Tuesday, a large short- period northeast (040-050 deg) swell of 10 to 12 feet at 10 to 11 seconds will persist due to a belt of near gale to gale force northeast winds several hundred miles northeast of Hawaii. This will keep rough east shore surf well above the HSA level and possibly reaching High Surf Warning mark of 15 ft, with seas above the SCA threshold through at least Wednesday night. As the dominant swell direction becomes more northeasterly, the threat of harbor surge will diminish. Expect the northeast swell energy to lower as local trade winds begin to decline on Thursday, with east shore surf steadily dropping on Friday and the weekend.
A small south swell is maintaining south shore surf near summertime background levels. A slightly larger pulse may arrive on Tuesday, peak on Wednesday and early Thursday, and then fade by Friday.

Fire weather

Breezy to locally strong trades will continue across the state through the week. Relative humidity may briefly fall into the upper 40s on Tuesday for isolated leeward areas, but low-level moisture embedded within the trades should prevent this from being widespread. Additional areas of moisture moving into the state should help to keep relative humidity from reaching critical thresholds for the remainder of the week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Tuesday for Niihau, Oahu North Shore, Olomana, Maui Windward West, Kauai North, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai Southeast, Molokai North, Maui Central Valley North, Windward Haleakala, Kipahulu, Big Island East, Big Island North.
Small Craft Advisory until 6 AM HST Thursday for all Hawaiian waters,

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