Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs around 89 near the shore to around 78 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows around 73 near the shore to around 63 above 3000 feet. East winds up to 15 mph.

Tuesday: Mostly sunny. Highs around 90 near the shore to around 78 above 3000 feet. East winds up to 15 mph.

South Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 83 to 90. East winds 10 to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with isolated showers. Lows around 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 83 to 91. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 77 to 87 in the valleys to around 68 above 4000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 72 in the valleys to around 60 above 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 77 to 87 in the valleys to around 68 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 90. East winds up to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with scattered showers. Lows 67 to 75. Southeast winds up to 10 mph. Chance of rain 30 percent.

Tuesday: Mostly sunny with isolated showers. Highs 79 to 90. East winds up to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 76 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 66 to 77. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny with isolated showers. Highs 76 to 88. East winds around 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trade winds will continue with passing overnight to early morning showers through the end of the week. A slight increase in showers may develop from Tuesday night to Wednesday morning, especially over the eastern islands. Trade wind speeds will decrease in strength with expanding afternoon sea breezes over each island from Thursday into the weekend.

Discussion

Local Hawaiian radar imagery shows a few showers drifting into the windward slopes of each island on the easterly trade winds this morning. The upper air balloon soundings from 2 AM HST keep subsidence temperature inversion heights in the 4,000 to 6,000 foot range, which indicates a fairly stable weather pattern.
For most of the week we will see passing showers mainly over windward and mountain areas of each island, favoring the typical overnight to early morning hours. One wrinkle in this rainfall forecast will occur from Tuesday night to Wednesday as a weak disturbance moves from east to west down the island chain. Expect shower coverage to increase during this time period, especially over the eastern half of the state.
Fairly stable trade winds will return by Wednesday afternoon. Large scale trade wind speeds will weaken slightly from Thursday onward, allowing local scale sea breezes to expand in coverage over each island lasting into the weekend.

Aviation

Surface high pressure northeast of the state will continue to generate moderate trades through the forecast period. Expect limited low clouds and light showers along windward and mauka areas. Brief MVFR possible within any heavier showers, otherwise VFR conditions prevail.
No AIRMETs are currently in effect.

Marine

High pressure northeast of the islands will keep moderate to locally fresh trades in place through Thursday. Wind speeds may flirt with Small Craft Advisory (SCA) criteria in the windier channels at times, but will likely not be consistent enough to warrant the issuance of a SCA. The trades will ease into the light to locally moderate range Friday through the weekend as the ridge north of the state weakens.
A small, medium period north swell will continue to fade out today. A new small, medium-period northwest swell is expected to arrive tonight, peak late Tuesday and Tuesday night, then decline as it shifts more northerly Wednesday and Thursday. Several additional small north swells should maintain small surf along north facing shores Friday through the weekend.
A small long-period southwest swell will continue to provide some small but inconsistent surf along south facing shores today. A new slightly larger south-southwest swell is expected to give a nice boost to south shore surf as it builds tonight, peaks Tuesday through Wednesday, then gradually declines through the rest of the work week. A small to moderate sized long-period south- southwest swell will gradually fill in late Saturday and Saturday night, then peak with swell heights of 3 to 4 feet next Sunday and Monday. This swell will give a sizable late season boost to south shore surf, potentially reaching advisory levels.
East shore surf will remain small through most of this week, although select spots with more northerly exposure could see some of the north swells throughout the week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov