Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny. Breezy. Highs around 85 near the shore to around 73 above 3000 feet. East winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Isolated showers after midnight. Lows 67 to 72 near the shore to around 60 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 85 near the shore to around 72 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 87. Northeast winds 15 to 25 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 69. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 80 to 87. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 72 to 79 in the valleys to around 63 above 4000 feet. East winds 10 to 25 mph decreasing to up to 25 mph in the afternoon. Chance of rain 40 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 61 to 66 in the valleys to around 56 above 4000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 71 to 78 in the valleys to around 63 above 4000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 74 to 85. East winds up to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 62 to 71. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 73 to 84. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

East Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 71 to 82. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 72. Northeast winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 71 to 83. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A high pressure system far north of the Hawaiian Islands will slowly drift eastward over the next few days with slightly lower wind speeds forecast in the breezy range starting later tonight through Monday. Brief showers are expected through Saturday night, expect increasing shower trends from Sunday into Tuesday. Longer range guidance continues to show an unstable wet weather pattern brewing late next week with shower trends in the current weather grids.

Discussion

The satellite imagery this morning continues to show stable cloud bands drifting into the islands on the strong trade winds. Expect a fairly stable pattern with continued brief periods of showers favoring windward and mountain areas through tonight. Scattered high cirrus clouds continue to stream over the state, enhancing tropical sunrise and sunset colors. Upper air soundings from Lihue and Hilo over the past 24 hours are showing the temperature inversion heights ranging from 5,000 to 7,500 feet.
A strong high pressure system far north of Hawaii will continue to produce windy trade winds through the afternoon hours. This high will slowly drift eastward over the next few days with trade winds gradually weakening into the breezy range later tonight. Wind advisories over the eastern island were extended through this afternoon and will likely be dropped by tonight as the wind speeds slowly decrease below advisory thresholds. The ridge north of the island weakens further on Tuesday with decreasing trade winds as a cold front approaches the region from the northwest. More variable winds are forecast from Wednesday onward, as wind directions shift around ahead of a cold frontal system moving into the region from the northwest.
Drier trade wind weather will continue today and tonight as a strong ridge aloft will keep trade wind inversion heights in the 5,000 to 7,000 foot range. A band of unstable clouds and showers, likely remnants from an old dissipated cold front, will move into the Hawaii region on the trade winds by Sunday morning. This unstable low level cloud band will lift trade wind inversion heights into the 7,000 to 10,000 foot elevation range on Sunday and Monday, increasing shower trends across the islands. The highest chances for showers will occur in the overnight to early morning hours along windward and mountain areas. An upper level trough moves in northeast of the Big Island on Tuesday and Wednesday keeping wet weather in the forecast. Longer range guidance continues to show an unstable wet weather pattern brewing late next week with shower trends in the current weather grids.
Global model consistency has shown larger than normal changes from run to run for the Thursday to Saturday time periods. This brings additional uncertainty into the forecast wet weather details for this time period. For now we will take a broad brush model ensemble approach to minimize errors from individual model solutions. Stay tuned for changes to the forecast as unstable wet weather remains in this long range outlook.

Aviation

Moderate to locally strong trade winds will guide light showers off the Pacific towards north and east facing slopes and coasts of the Hawaiian Islands. Brief MVFR conditions are to be expected in these passing showers. Mountain obscuration could become an issue for Windward Big Island or East Maui later this morning as shower activity increases.
AIRMET Tango remains in effect for moderate turbulence over and immediately south through west of mountains. Conditions are likely to persist through the remainder of the weekend due to a combination of strong winds in the lower levels and a sharp inversion aloft.

Marine

High pressure north of the islands will keep strong trade winds blowing through early next week, with the trades expected to remain particularly strong today. Gale force winds will continue in the windier waters around Maui and the Big Island, with Small Craft Advisory (SCA) level winds elsewhere today. The trades will ease slightly by Sunday, but SCA level winds will likely continue for most marine zones through Tuesday. An approaching cold front is forecast to decrease the trades below SCA levels around the middle of next week.
Strong trade winds will keep east shore surf elevated and well above normal through early next week. The High Surf Advisory has been extended through 6 PM this evening. Surf along east facing shores will lower to near or below normal levels around the middle of next week as the trades back off.
Surf along north and west facing shores will remain small and well below normal through the weekend. A small northwest and a small north swell will give surf a boost along north and west facing shores Monday through Wednesday. A new large northwest swell could bring warning level surf to north and west facing shores late next week.
Surf along south facing shores will remain small with only background south swell energy through the middle of next week. A new small south swell could give south shore surf a slight boost late next week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for east facing shores of Kauai Oahu Molokai Maui and the Big Island.
Wind Advisory until 6 PM HST this evening for portions of Maui and Hawaii Counties.
Small Craft Advisory until 6 PM HST Sunday for all coastal waters and channels outside of the Gale Warning.
Gale Warning until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov