Photo Credit: Jason Weingardt

West Kaua’i

Today: Windy. Mostly sunny with isolated showers. Highs around 78 near the shore to around 66 above 3000 feet. East winds 15 to 30 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 67 near the shore to around 56 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs around 79 near the shore to around 67 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Partly sunny with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 77. East winds 20 to 25 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 68. East winds 10 to 15 mph. Chance of rain 50 percent.

Tuesday: Partly sunny with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 78. East winds 10 to 15 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Partly sunny. Windy. Showers likely in the morning, then scattered showers in the afternoon. Highs 65 to 73 in the valleys to around 60 above 4000 feet. East winds 15 to 30 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 56 to 61 in the valleys to around 50 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 66 to 74 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Today: Windy. Partly sunny with scattered showers. Highs 70 to 77. East winds 10 to 30 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 59 to 68. East winds 10 to 15 mph. Chance of rain 50 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 71 to 78. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 70 to 77. East winds 20 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 57 to 69. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs 71 to 78. East winds 10 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Strong high pressure to the distant north-northeast, will gradually weaken as it drifts slowly southward during the next severals days. Breezy to windy easterly trades will persist across the state today before gradually easing to more typically moderate to locally breezy speeds Wednesday into Thursday. Trade wind showers will focus mainly over windward and mauka areas with some showers spilling over to the leeward communities at times. The trades will ease into the light to moderate range over the weekend as a couple of fronts pass by north of the island chain.

Discussion

Currently at the surface, a 1033 mb high is centered around 1000 miles north-northeast of Honolulu, while a cold front is located to the distant west-northwest and around 1050 miles from Kauai. The gradient over the state continues to produce breezy to locally windy trades early this morning. Infrared satellite imagery mostly cloudy skies in windward areas and partly cloudy conditions in leeward locales. Radar imagery shows scattered to numerous trade showers moving into windward slopes and coasts, with some of these showers reaching leeward areas at times. Main short term focus remains on wind trends during the next couple days.
Strong high pressure to the north-northeast will settle southward and closer to the islands today, then remain anchored northeast of the state while very slowly weakening tonight through Thursday. Breezy to locally windy trades are expected to continue through Tuesday, before easing to breezy levels Wednesday and to moderate levels Thursday. A couple fronts passing by to the north of the state will ease the trades further late in the week, with moderate trades Friday becoming light over the weekend.
A Wind Advisory remains in effect for portions of Maui County and the Big Island through 6 PM this evening. Winds have dropped below advisory threshold over the western end of the state, so the advisory has been cancelled for Niihau, Kauai and Oahu.
As for the remaining weather details, fairly typical trade wind weather can be expected through the work week, with showers favoring windward and mauka areas and a stray shower reaching leeward communities from time to time. As the trades ease next weekend, a few afternoon interior/leeward showers will be possible, otherwise showers will continue to favor windward terrain.

Aviation

Gusty easterly trades will persist through the 24-Hr TAF period as strong high pressure shifts northeast of the region. Bands of clouds with embedded showers will focus over windward slopes, which support MVFR CIGS/VSBYS conditions periodically through the morning hours. Elsewhere, VFR conditions will prevail, with an occasional light shower spilling over into the leeward areas of the smaller islands.
AIRMET Tango remains in effect below 10000 feet for moderate lee turbulence downwind of all islands due to strong northeast to east winds.
AIRMET Sierra remains in effect through the early morning hours today for most windward areas due to the bands of low clouds/SHRA moving through.

Marine

Strong- to gale-force easterly trade winds produced by a high pressure system north of the state will continue today, then shift out of the east-southeast and the gradually weaken from Tuesday through Thursday. A combination of rough, short period wind waves in response to these winds, a large, north-northeast swell moving through the region, and a moderate northwest swell currently moving into the region will support hazardous marine conditions across all Hawaiian waters through the first half of the week. Expect gales over the typically windier channels between Maui County and the Big Island, the leeward waters of Maui County, Maalaea Bay (north winds), and over the waters around South Point of the Big Island through today. Small Craft Advisory conditions will continue for all waters outside of the Gale areas into Tuesday. These winds and seas should ease as the ridge weakens north of the region for the second half of the week.
Surf along exposed north and east facing shores will remain rough due to a mix of locally-driven wind waves and a medium-period northeast (020-040 deg) swell moving through. High surf advisories remain in effect for these areas. The northeast swell will slowly decline over the next few days as the trade winds begin to ease.
Surf along north and west facing shores will trend up today as a long period northwest (310-320 deg) swell arrives. This swell will peak later today, producing advisory level surf over exposed north and west facing shores, then ease Tuesday through the second half of the week. Models show the next significant northwest swell arriving late next weekend.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Olomana, Maui Windward West, Kauai North, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala, Kipahulu, Big Island East, Big Island North.
Wind Advisory until 6 PM HST this evening for Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Molokai, Maui Central Valley North, Windward Haleakala, Kipahulu, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 PM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.
Gale Warning until 6 PM HST this evening for Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov