Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 86 near the shore to around 74 above 3000 feet. Northeast winds up to 15 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to around 61 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 84 to 90 near the shore to around 75 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny with scattered showers. Highs around 83. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 69 to 74. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs 83 to 90. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Scattered showers in the morning, then showers likely in the afternoon. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. 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 70 percent.

Monday: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 74 to 81 in the valleys to around 67 above 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 76 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 73. East winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs 77 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 76 to 84. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 76. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Mostly cloudy with scattered showers. Highs 75 to 85. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Moderate trades will focus showers over windward and mauka areas through mid-week. Locally heavy showers remain possible through today, thanks to a receding upper trough northeast of the islands. Expect breezy trades and greater shower coverage by late Wednesday through Thursday.

Discussion

An upper trough extending northeast from the main Hawaiian Islands enhanced showers across Puna district of the Big Island last evening, but this activity has diminished considerably this morning. The Big Island is mostly clear at this hour, while isolated to scattered moderate showers blown in by the trades affect windward areas of the smaller islands. With the upper trough expected to gradually retreat to the northeast away from the islands over the next few days, the probability for thunderstorm and heavy shower development drops too low to include in the forecast with confidence. Expect a resumption of typical trade wind flow and weather, with clouds and showers favoring windward and mauka areas.
Models show an area of deep moisture east of 150W will eventually pass across the islands, probably in the Wednesday to Thursday time frame. Expect renewed upper troughing west of the islands during the latter half of the week. As this forces ridging to amplify north of the islands, surface pressure rises over the northeast Pacific Basin will boost trade wind speeds across local waters. Stronger trades, combined with increased moisture coming in from the east, may trigger a brief period of wetter trades Wednesday and Thursday.

Aviation

Moderate trade winds will prevail throughout the next couple of days with high pressure north of the state. Therefore, expect scattered showers to occur along windward areas with isolated activity elsewhere as a drier trade wind pattern resumes across the island chain. Although MVFR ceilings and visibilities may occur at times from passing clouds and showers, VFR conditions are expected to prevail at most locations.
Latest satellite imagery and surface observations reveal that the extensive showers and clouds that were observed across windward sections of the Big Island overnight have diminished early this morning. As a result, AIRMET Sierra for tempo mountain obscuration has been cancelled. There are currently no AIRMETS in effect and none are anticipated today.

Marine

Expect moderate trade winds to continue through Monday across all Hawaiian waters. A high pressure system will build in from the north early next week producing moderate to locally strong trade winds from Tuesday onward where Small Craft Advisory thresholds may be reached for the typical windier waters around Maui and the Big Island.
Small medium period overlapping northwest and north swell energy will keep small surf going along north facing shores through Wednesday. A brief longer period northwest pulse of swell energy may arrive by Thursday providing a small bump in surf heights for north facing shores into Friday.
Background small medium period south swell energy will continue to keep fun size surf along south facing shores for most days this week. Downward south swell trends are in the long range forecast by the end of the week. Surf heights along west facing shores will remain small through the week with a bit of south swell wrap keeping west side surf heights above flat levels.
Surf along east facing shores will remain small through Monday. Strengthening trade winds on Tuesday will cause surf heights along east facing shores to rise through the middle of the week, as the high pressure ridge builds north of the region and the trade winds strengthen.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov