West Kaua’i

Today: Sunny. Isolated showers in the morning. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 74 near the shore to around 62 above 3000 feet. Northeast winds up to 15 mph becoming around 10 mph after midnight.

Tuesday: Sunny. Highs around 89 near the shore to around 76 above 3000 feet. Northeast winds up to 10 mph.

South Kaua’i

Today: Mostly sunny with isolated showers. Highs 82 to 90. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 82 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 88 in the valleys to 65 to 70 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 67 to 72 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 88 in the valleys to 64 to 69 above 4000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs 80 to 89. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 66 to 74. East winds up to 15 mph becoming around 10 mph after midnight. Chance of rain 20 percent.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 80 to 89. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 77 to 88. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 67 to 77. East winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 75 to 88. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A low pressure system north of the island chain will remain embedded in the broader regional high pressure ridge pattern. This weak low pressure system will decrease the trade wind speeds across the state over the next several days. Trade winds will blow at moderate levels for most days this week with a slight increase possible on Tuesday as another weak trough passes just south of the Hawaiian Islands. Typical seasonal summer weather will trend conditions towards the dry side with limited showers lasting into the weekend.

Discussion

The satellite imagery this morning shows a low pressure system stalled out just north of the Hawaiian Islands. This system remains embedded in the broader regional high pressure ridge and will produce a slight decrease in trade wind speeds through much of this week. Some cloud stable cloud bands this morning will continue to drift over each island on the trade winds. However the upper level ridge directly over the state will keep temperature inversion heights in the 5,000 to 6,000 foot range, limiting shower activity across the state.
Expect a typical summer weather pattern with moderate trade wind speeds to continue through the week. This decrease in large scale winds will allow a hybrid expansion of sea breezes across western terrain sheltered slopes of each island. Converging sea breeze and trade winds may produce isolated afternoon showers over mountain slopes and island interior sections. A weak trough passing just south of the state on Tuesday may briefly increase trade wind speeds and inject some additional moisture into the Big Island weather pattern, most noticeable along the Kona slopes enhancing some of the sea breeze driven shower activity. Otherwise the upper level (500mb) ridge will keep stronger subsidence (downward moving air) directly over the islands capping cloud development and keeping drier weather in the forecast into the upcoming weekend.

Aviation

Trade wind speeds will decrease to more moderate levels for the next several days due to a low pressure system embedded in the larger ridge just north of the Hawaiian Islands. Typical drier summer weather will continue with prevailing VFR conditions.
No AIRMETs are in effect and none are expected.

Marine

High pressure N of the Hawaiian Islands maintains moderate to fresh trades through the week. Small swell energy emanating from the southerly quadrant slowly declines through today. A series of small longer period S swells then arrive by Tuesday providing a modest boost to S shore surf through Friday. Surf along N and W facing shores remains nearly flat while surf along E shores will remain characterized by short period chop.

Fire weather

Typical summer fire weather conditions will continue through the week due to the low relative humidity values. Very dry conditions were observed across the state yesterday, with minimum RH levels falling into the 30 to 40 percent range. These lower RH levels will continue for much of this week. Lower wind speeds will be the limiting factor for reaching critical fire thresholds, and these wind limited conditions will likely continue into the upcoming weekend. Temperature inversion heights near Maui and the Big Island will range from around 5,500 to 6,500 feet today.

HFO Watches/Warnings/Advisories

None.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.