Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with numerous showers in the afternoon. Highs around 82 near the shore to around 70 above 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Numerous showers early in the evening, then isolated showers in the late evening and overnight. Lows around 69 near the shore to around 58 above 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 83 near the shore to around 71 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Breezy. Partly sunny with numerous showers. Highs around 79. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 65 to 70. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80. East winds 10 to 15 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 69 to 76 in the valleys to around 60 above 4000 feet. East winds up to 15 mph. Chance of rain 80 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 58 to 63 in the valleys to around 51 above 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Tuesday: Mostly cloudy with numerous showers. Highs 70 to 77 in the valleys to around 61 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

North Kaua’i

Today: Mostly cloudy with scattered showers. Highs 72 to 82. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69. East winds up to 15 mph becoming around 10 mph after midnight. Chance of rain 50 percent.

Tuesday: Mostly cloudy with scattered showers. Highs 73 to 83. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 81. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 58 to 71. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly cloudy with scattered showers. Highs 73 to 82. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A return to more typical trade wind weather is expected today, with this pattern then prevailing through next weekend. Clouds and showers will generally favor windward areas, particularly during nights and mornings. A trough aloft north of the state will provide high cloud cover at times and may enhance some of the low level showers moving in from the east and allow a few of these showers to reach leeward communities as well.

Discussion

Currently at the surface, a 1035 mb high is centered around 1400 miles north of Honolulu, with a very weak and broad trough of low pressure just north of Kauai. This trough continues to influence the winds locally, keeping trades in the light to moderate range. Infrared satellite imagery partly to mostly cloudy conditions across the state, with cloud coverage the highest over the Big Island and in windward poritons of the smaller islands. Radar imagery shows scattered to numerous showers moving into windward areas, with a few showers spilling over to leeward communities at times. Main short term focus revolves around rain chances and trade wind trends.
The weak trough of low pressure north of Kauai will shift westward and dampen out today, while strong high pressure remains nearly stationary to the distant north. With the trough exiting west of the state, the trades are expected to strengthen to moderate to locally breezy levels later today, with little change in trade wind strength then expected through next weekend.
As for the remaining weather details, as the trades strengthen today, showers will favor windward and mauka areas this morning, with daytime heating and localized sea breezes leading to the development of scattered showers in leeward and interior areas this afternoon. The airmass could be unstable enough to allow a thundestorm to pop over the Big Island slopes this afternoon, so have included a slight chance of thunderstorms in the forecast here. Showers should dwindle rather quickly this evening in leeward areas, with the shower focus transitioning over to windward areas overnight. Fairly typical trade wind weather should then prevail through the remainder of the week and into next weekend, with showers favoring windward and mauka areas, particularly during nights and mornings. A few showers will spread to leeward communities at times due to a weak and elevated inversion resulting from troughing aloft holding in place just to the north of the state. This troughing will also bring periods of scattered to broken cirrus to the island chain, as well as some slightly wetter than normal trade wind weather at times. An isolated thunderstorm can't be ruled out over the Big Island slopes again Tuesday afternoon.

Aviation

High pressure will slowly build into the region from the north as a broad low level trough moves west. Trade wind speeds will gradually increase over the next two days. Expect moderate trade winds today and tonight with passing showers mainly affecting windward and mountain areas in the overnight to early morning hours.
There are no AIRMETs currently in effect.

Marine

A surface high pressure system building far north of the area will likely cause the trade winds to gradually strengthen today. The current forecast does not have Small Craft Advisory (SCA) conditions through Tuesday. However, the winds may reach the SCA criteria by Wednesday over the typically windier waters adjacent to the islands of Maui County and the Big Island. There may be some fluctuations in trade wind speeds later this week, since the surface high far north of the area may weaken slightly during the Thursday / Friday time period.
Small, medium-period south-southwest swell energy will likely continue to produce modest surf along south facing shores into mid-week. There will be a brief lull in swells originating from the Southern Hemisphere later this week, with only small, background surf expected along south facing shores from Thursday into Friday. A small, long-period south-southwest swell arriving next weekend may provide a slight increase in surf heights along south facing shores.
Expect below normal surf along east facing shores early this week due to the relatively weak trade winds locally and upstream of the state. As the trades strengthen, there will likely be a slight increase in choppy surf along east facing shores by mid- week.
The current small west-northwest swell will provide a slight boost in surf heights along most exposed north and west facing shores into Tuesday. This swell will fade by mid-week, so expect small, background summertime surf along north facing shores from Wednesday through next weekend. For the long-range, the latest guidance from the WAVEWATCH III Model continues to indicate a small, long-period west swell produced by northwest Pacific Typhoon Mawar may arrive around Tuesday, June 6.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov