Kauai Weather

West Kaua’i

Today: Sunny. Highs 76 to 82 near the shore to around 68 above 3000 feet. Light winds.

Tonight: Mostly clear. Lows 60 to 65 near the shore to around 53 above 3000 feet. Light winds.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 76 to 83 near the shore to around 68 above 3000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Sunny. Highs 75 to 82. Northeast winds up to 10 mph.

Tonight: Mostly clear. Lows around 64. Northeast winds up to 10 mph.

Monday: Sunny. Isolated showers in the afternoon. Highs 75 to 83. Northeast winds up to 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny with isolated showers. Highs 67 to 74 in the valleys to around 61 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 53 to 63 in the valleys to around 51 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 68 to 74 in the valleys to around 60 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

North Kaua’i

Today: Sunny with isolated showers. Highs 69 to 78. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 57 to 65. Northeast winds up to 10 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 70 to 78. Northeast winds up to 10 mph shifting to the north in the afternoon. Chance of rain 20 percent.

East Kaua’i

Today: Sunny. Highs 69 to 80. North winds around 10 mph.

Tonight: Partly cloudy with isolated showers. Lows 57 to 68. North winds around 10 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 69 to 80. North winds up to 10 mph. Chance of rain 20 percent.

Synopsis

Drier air filling in behind a weak front east of Big Island is creating a crisp, cooler morning with mainly clear to partially cloudy skies. Very pleasant weather today as light to gentle northerly winds slowly veer back to trades by tonight. A dry trade regime will persist the next couple of days with typical trade wind-like weather in place throughout the week. Light precipitation will focus on windward exposures and along mauka slopes. A weak trough passage north of the islands will slightly increase rain chances Tuesday.

Discussion

A dry and more stable air mass has filled in across the majority of the island chain behind the front that was associated with the storm low that introduced last Thursday's severe weather. This morning's Kauai sounding verifies this resident dry air mass under established west-northwest flow throughout the column. Lihue's 0.6 inch precipitable waters registers in the lower 10 percentile range for early February. Responding morning surface dew point temperatures have fallen into the mid to upper 50s under gentle post-frontal northerlies. The state falls just northeast of upper ridging straddling 10N while, at the surface, weak high pressure advances in from the west. As lower level high pressure fills in the void left by the aforementioned northeast-exiting storm low, regional winds will veer back to trades later today. Limited sub-850 mb moisture trapped beneath a fairly stout 6k ft inversion will assist in producing thicker clouds and isolated light showers as a result of orographic lifting along north and northeastern- facing mauka slopes.
A couple of boundary passages Tuesday and late Thursday into Friday will increase rain shower chances from slight to moderate probabilities for many better exposed windward communities and at higher elevation. A weak and shallow frontal boundary and associated weak upper trough will pass north of the state Tuesday. This will provide a slight increase in windward clouds and shower activity within established trade flow. EC ensemble 90 percentile guidance data increases QPF on Tuesday a few hundredths to a couple of tenths of an inch over all windward exposures and at elevation. Shortwave energy diving into a larger scale troughs far north northeast of the state from Tuesday through Thursday may lower heights far enough south to touch the islands. A surface reflection of a weak front may pass across to the north and briefly disrupt trade flow Thursday. Moisture depth may be too shallow for a front to do much with upon its passage. The majority of the EC ensemble members increase rain coverage from west-to- east primarily north of the islands Thursday while only a few GFS members want to play into this slightly more wet pattern. Either way, no significant weather is expected from this weak wind-disrupting boundary passage. High pressure west of the island chain will pass over Friday and, once northeast of the state, trade flow will return for the weekend. After this relatively drier week, a more wet pattern is beginning to take shape early next week. Deeper mid layer moisture pooling up over the state downstream of a more pronounced North Central Pacific trough does increase a higher regional QPF signal across more ensemble members beyond Day 8.

Aviation

A dry and stable airmass is settling in over the islands, and will limit clouds and showers into tomorrow. Northerly winds will veer to the northeast by Sunday, leaving gentle to moderate northeast trade winds around the islands.
No AIRMETs in effect, and none are expected today.

Marine

Gentle to moderate north winds are expected to veer northeasterly and strengthen slightly today as a weak high pressure northwest of the state will slowly track eastward through the middle of the week. Trade winds look to remain just under Small Craft Advisory through the forecast period for the windier waters and channels around Maui County and the Big Island.
A combo of a moderate to large medium period north-northeast swell and a small, medium period northwest swell will continue to produce moderate to large surf along north facing shores. The north swell will gradually fill in this evening, peak tonight and Monday before gradually declining through the middle of the week. A High Surf Advisory (HSA) is possible during the peak of the swell for north facing shores. Another small to moderate northwest swell is also expected to fill Monday, and peak Tuesday before declining through the end of next week.
Surf along east facing shores will remain small except for shorelines exposed to the north-northeast swell through the first half of the week. Surf along south facing shores will remain tiny through the forecast period with mainly background energy.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov