Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny. Scattered showers in the afternoon. Highs around 85 near the shore to around 73 above 3000 feet. Light winds. Chance of rain 30 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 65 to 70 near the shore to around 56 above 3000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny. Scattered showers in the afternoon. Highs around 86 near the shore to around 74 above 3000 feet. East winds up to 10 mph in the morning becoming light. Chance of rain 30 percent.

South Kaua’i

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

Tonight: Partly cloudy with isolated showers. Lows 63 to 69. Northeast winds around 10 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs around 83. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny with scattered showers. Highs 72 to 79 in the valleys to around 63 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 56 to 61 in the valleys to around 51 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny with scattered showers. Highs 73 to 80 in the valleys to around 64 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 75 to 84. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 59 to 69. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Tuesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 85. East winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 83. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 57 to 70. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 76 to 84. East winds up to 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

The presence of weak ridging to the north will keep light to moderate trades in place through mid week, with localized land and sea breezes expected in the more sheltered areas. Showers will favor windward slopes and coasts during nights and mornings, and interior and leeward areas each afternoon. A return to more typical trade wind weather featuring mainly windward showers and a few leeward spillovers is expected late Thursday through the weekend, with trades possibly reaching breezy levels from Friday onward.

Discussion

Currently at the surface, a weak nearly stationary front is located around 450 miles north of Kauai, while a weak surface ridge is positioned around 225 miles north of Honolulu. The resulting gradient is producing light to moderate trade winds, with land breezes present in sheltered areas. Infrared satellite imagery shows some high clouds streaming over the Big Island and some low clouds being carried into windward areas with the trades. Overall, partly cloudy conditions prevail, with a few windward sections of the smaller islands and portions of the Big Islands experiencing more extensive cloud cover. Radar imagery shows isolated to scattered showers moving into windward areas, with mainly dry conditions in leeward locales. Main short term focus revolves around rain chances and trade wind trends.
A weak ridge of high pressure north of the islands will remain nearly stationary through mid week, keeping the gradient loose and trade winds in the light to moderate range. The trades will be light enough to allow for overnight land breezes and daytime sea breezes in many leeward areas and even some windward sections over the western end of the state. The ridge will strengthen and lift northward Thursday, with breezy trades possible Friday through the weekend.
As for the remaining details, a fairly stagnant weather pattern can be expected through Thursday, with showers favoring windward areas during nights and mornings, then transitioning over to interior and leeward areas each afternoon and early evening. A return to more typical trade wind weather featuring windward showers and the occasional leeward spillover is expected late Thursday through the weekend.
Periods of scattered to broken high cloud cover will continue to mainly affect the eastern end of the state today through Tuesday. The high clouds should mostly dissipate Wednesday and Thursday, with some more high clouds possible at times Friday through the weekend.

Aviation

A frontal system moving north of the state will keep surface high pressure weak and allow for light trades to persist across the islands through the forecast period. Thus, scattered showers will mainly affect windward areas this morning and may bring brief periods of MVFR ceilings and visibility.
By this afternoon, sea breeze development along the leeward coasts will lead to scattered shower development over the interiors and along leeward locations. Partly cloudy elsewhere with VFR conditions.
No AIRMETs are currently in effect.

Marine

Light to moderate easterly trade winds will continue through midweek as a weakness in the ridge to the north lingers. Despite the lighter winds, expect localized pockets of fresh breezes near the coasts and over the windier locations, especially during the late morning and afternoon hours due to a combination of the orientation of the terrain, wind direction, and heating. Guidance shows a return of fresh to strong easterly trades by the end of the week.
Surf along south facing shores will remain up through midweek as a mix of background long-period south-southwest and south- southeast swells continues. As these sources fade by Thursday, another small background south-southwest swell is expected Friday into next weekend.
Surf along exposed north and west facing shores will remain near the seasonal average each day through the first half of the week. An out of season west-northwest swell is expected to arrive late Wednesday through Wednesday night, peak Thursday, then ease into the weekend. Recent satellite-derived winds and seas reflected this potential and showed a nice sized fetch of strong- to gale- force westerly winds focused at the islands down the 310 degree directional band with seas up around 25 ft over the far northwest corner of the basin near Kamchatka.
Surf along east facing shores will remain small through the week due to the light trades locally and far upstream over the eastern Pacific. An upward trend is possible next weekend as the trades return to fresh levels.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov