Photo Credit: Jason Weingardt

West Kaua’i

Today: Sunny with isolated showers. Highs around 85 near the shore to around 75 above 3000 feet. Northeast winds up to 15 mph shifting to the southeast in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 61 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Columbus Day: Mostly sunny with isolated showers. Highs around 85 near the shore to around 75 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

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

Tonight: Mostly cloudy with isolated showers. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Columbus Day: Partly sunny with isolated showers. Highs around 84. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny with isolated showers. Highs 73 to 79 in the valleys to around 68 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 65 in the valleys to around 57 above 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Columbus Day: Partly sunny with isolated showers. Highs 73 to 79 in the valleys to around 68 above 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny with isolated showers. Highs 75 to 84. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 65 to 73. East winds around 10 mph. Chance of rain 20 percent.

Columbus Day: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 75 to 84. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 75 to 85. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 63 to 74. Northeast winds around 10 mph. Chance of rain 20 percent.

Columbus Day: Partly sunny with isolated showers. Highs 75 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high far northwest of the main Hawaiian Islands will slowly track east through Wednesday, allowing the return of breezy trades with minor strength fluctuations. A front will approach the islands from the north during the second half of the week, causing trades to decrease. Expect clouds and showers to favor windward and mauka areas through midweek. During the second half of next week, lighter winds will result in a hybrid trade wind and land/seabreeze pattern.

Discussion

A high far northwest of the main Hawaiian Islands will slowly build, causing local trade winds to continue strengthening. Radar and satellite loops show scattered showery low clouds favoring windward areas of most of the islands. Patchy broken low clouds cover windward and mauka sections of Kauai. Overnight soundings showed 1.2 to 1.6 inches of PW, with positive lifted index values, indicating a modestly stable airmass with seasonal to slightly drier than normal conditions.
Models show the high will slowly track east through the first half of the week, maintaining breezy trades and keeping clouds and showers across windward and mauka regions. However, increased moisture will pass near or just south of the state, fueling increased shower activity Monday night for the eastern half of the state and Tuesday into early Wednesday morning for the rest of the state. Airmass stability will increase Wednesday and Thursday as upper ridging builds in over the region, limiting shower activity once again. A front will approach the state from the north and weaken toward the end of the forecast period, weakening our winds and allowing a hybrid trade wind and land/seabreeze pattern to develop.

Aviation

A high pressure ridge north of Hawaii will keep moderate trade winds in the forecast with fairly stable conditions and limited shower activity. Cloud bands moving into Kauai and the Big Island will produce some enhanced shower activity through the early morning hours. Otherwise drier conditions with isolated showers mainly over windward and mountain areas. VFR conditions will prevail with brief periods of MVFR conditions in showers.
AIRMET Sierra in effect for mountain obscuration over north through east sections of Kauai and the Big Island this morning. This AIRMET will likely diminish after 20Z.

Marine

A surface high pressure system located far northwest of the islands will move slowly east to a position far north of the state during the next couple of days. This will likely maintain moderate to locally fresh trade winds across the state early this week. The latest forecast guidance indicates trade wind speeds will be just below the Small Craft Advisory criteria over the typically windier waters adjacent to the islands of Maui County and the Big Island from Monday into Tuesday. The surface high pressure system will likely push east to a position far northeast of the state from Tuesday through mid-week.
The current north swell will continue to gradually lower through early Monday. A new northwest swell arriving late Monday will likely produce a modest increase in surf along exposed north and west facing shores from Monday night and Tuesday through early Wednesday. The forecast guidance appears to indicate a larger, reinforcing northwest swell may arrive late Wednesday, and persist through Friday.
The current small, south-southwest swell will gradually lower from later today through tonight. Expect small background surf along south facing shores on Monday due to a combination of small south and southeast swells. The wave model guidance indicates a new south swell may arrive Tuesday, which could produce a slight increase in surf along south facing shores through mid-week. Expect modest, choppy surf along east facing shores through mid- week due to the moderate to locally fresh trade winds.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov