Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 88 near the shore to around 76 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 70 to 75 near the shore to around 61 above 3000 feet. East winds up to 15 mph shifting to the northeast after midnight.

Independence Day: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 15 mph shifting to the southeast in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 85. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 68 to 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Independence Day: Breezy. Mostly sunny with isolated showers. Highs around 84. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 61 to 66 in the valleys to around 56 above 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Independence Day: Mostly sunny with scattered showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 87. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 74. Southeast winds up to 15 mph. Chance of rain 20 percent.

Independence Day: Mostly sunny with isolated showers. Highs 77 to 86. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 78 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 62 to 76. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Independence Day: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 77 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

High pressure northeast of the islands will keep moderate trade winds blowing through mid week, with the trades becoming breezy Thursday through the weekend. Low clouds and showers will favor windward and mauka areas, especially during nights and mornings. Leeward communities will be mostly dry, except on the Big Island, where clouds and a few showers are expected to develop each afternoon and evening.

Discussion

Currently at the surface, a 1030 mb high is centered around 1800 miles northeast of Honolulu, with a ridge extending southwest to a position around 700 miles north of Kauai. The resulting gradient is producing moderate trade winds across the island chain early this morning. Infrared satellite imagery shows mostly cloudy conditions in windward areas and partly cloudy skies in most leeward locales. Radar imagery shows scattered light showers moving into windward areas and a few decaying showers or sprinkles reaching leeward communities at times. Main short term focus revolves around rain chances.
High pressure will remain in place northeast of the state through mid week, keeping moderate trade winds blowing across the island chain. The high will then settle southward and closer to the area Thursday through the weekend, bringing a return of breezy trades to the islands.
As for the remaining weather details, a rather dry trade wind pattern is expected through mid week, with mid-level ridging holding strong across the region. Showers will be limited primarily to windward and mauka areas, particularly during nights and mornings, although a stray shower may reach leeward areas at times. Mid-level troughing developing just north of the islands in combination with stronger trade wind speeds, should bring an increase in trade wind showers beginning Wednesday night and continuing through next weekend.

Aviation

Moderate easterly trade winds will continue through the 24-hr forecast period and beyond, with clouds and showers favoring windward and mauka locations. Periods with MVFR CIGs/VSBYs are possible in and around passing showers this morning, especially over the eastern end of the state where a band of low clouds has moved in. Elsewhere, VFR conditions will prevail.
AIRMET SIERRA is in effect for north through east sections of Molokai, Maui, and the Big Island for mountain obscuration above 2000 ft due to clouds and showers.

Marine

A surface ridge far north of the state will slowly build far north of the state over the next few days. Moderate to locally strong trade winds are expected throughout the week. A Small Craft Advisory (SCA) is in place over the typically windier waters around Maui County and the Big Island through Wednesday. This SCA will likely need to be extended beyond Wednesday, since the locally strong trade winds are expected to persist and strengthen slightly in the second half of the week.
Surf along all shores is expected to remain flat to tiny through Friday. Small south and southeast swells will maintain small background surf along south facing shores. In the long range, a low pressure system from the Tasman Sea to the east of New Zealand, has generated a southwest swell that may boost surf heights along south facing shores over the upcoming weekend.
North facing shores may see a slight pulse out of the north- northwest Wednesday or Thursday. A larger north-northwest swell is possible this weekend, which could produce small surf along north and west facing exposures. East facing shores will remain small through the week before gradually building to modest heights later this week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov