Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly cloudy with scattered showers. Highs around 83 near the shore to around 72 above 3000 feet. South winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 68 near the shore to around 58 above 3000 feet. Light winds becoming southwest 10 to 15 mph after midnight. Chance of rain 30 percent.

Friday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 83 near the shore to around 72 above 3000 feet. South winds 10 to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83. Southwest winds around 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 68. Southwest winds around 10 mph. Chance of rain 30 percent.

Friday: Mostly sunny with isolated showers. Highs around 82. Southwest winds around 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Cloudy with scattered showers. Highs 72 to 79 in the valleys to around 66 above 4000 feet. Southwest winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 59 to 64 in the valleys to around 54 above 4000 feet. Southwest winds up to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 72 to 79 in the valleys to around 66 above 4000 feet. Southwest winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Cloudy with scattered showers. Highs 76 to 83. Southeast winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 61 to 70. Southeast winds up to 10 mph shifting to the south after midnight. Chance of rain 40 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 75 to 83. South winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Today: Cloudy with scattered showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 75 to 83. Southwest winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 60 to 71. Southwest winds up to 10 mph. Chance of rain 40 percent.

Friday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 75 to 84. Southwest winds up to 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A stationary front remains just northwest of Kauai with a high pressure ridge over the islands. This stable weather pattern will keep light southwesterly winds with land and sea breezes along terrain sheltered slopes for most islands through this weekend. An upper level trough will move over this front on Sunday, causing a weak cut off low to form by Monday just west of Kauai. Enough instability from this upper trough will increase shower chances over Kauai from Sunday into Monday. Long range guidance shows southerly winds aloft over Kauai County and Oahu with increasing shower activity from Monday through Wednesday.

Discussion

A stationary front remains just northwest of Kauai with a high pressure ridge locked in place over the Hawaiian Islands. This high pressure ridge over the islands will produce stable conditions in place for the short range weather forecast with temperature inversion heights in the 4,000 to 6,000 foot range limiting vertical cloud development. Surface observations and radar imagery this morning continues to show weak southwesterly flow over the state with no significant rainfall activity. Satellite imagery shows very little cloud cover from the Big Island to Molokai, with some high to mid cloud cover passing over Oahu and Kauai.
The high pressure ridge over the state will linger into Saturday keeping weather conditions over the islands fairly dry. Expect light southwesterly winds with afternoon sea breezes along terrain sheltered north and east sections of each islands and light offshore land breezes at night. Periods of high level cirrus clouds are forecast to drift over the western islands through the weekend, enhancing sunrise and sunset colors.
A strong upper level trough will approach the Hawaii region from the northwest from Sunday into Monday, divergence ahead of this upper trough will cause a surface low to form along the stationary front. Cold air aloft will become cut off from the mid latitude westerly flow and form a stationary cut off low about 500 miles northwest of Kauai. The surface low will deepen and move northwest under the upper level system from Monday through Wednesday. Southeast winds at the surface with south winds aloft may develop over Kauai and Oahu during this transition with inversion heights in the 8,000 to 10,000 foot range. Enough moisture and instability will keep passing showers in the forecast for these western islands from Monday through Wednesday. Drier conditions are expected over the islands in Maui and Hawaii Counties in more stable east to southeasterly winds.
Long range forecast guidance diverges significantly over the Hawaii region between the American (GFS) and European (ECMWF) models due to challenges in forecasting smaller scale convergence bands around the developing cut off low. The GFS remains on the wetter side of the forecast spreading periods of showers to all islands with the ECMWF keeping drier more stable conditions over Maui and Hawaii Counties. The weather forecast from Wednesday onward will certainly evolve over time as the location of the cut off low center and the small mesoscale convergence cloud bands forming around the low will be key players in our island by island rainfall activity. Stay tuned.

Aviation

Early this morning, low clouds and showers associated with a frontal boundary continue to stream just north of Kauai. Although the bulk of the showers and low clouds remain to the north, Kauai may be brushed with quick moving showers and low clouds from time to time through the morning hours before the band meanders even further north away from the island by the afternoon.
Elsewhere across the state, light southerly winds and mostly dry conditions are expected with a surface ridge axis near the Big Island. Any showers will remain both minimal in coverage and light in intensity.
No AIRMETs are currently in effect, and none are anticipated at this time.

Marine

A ridge will continue to meander over and south of the islands through the rest of the week as a frontal boundary remains nearly stationary north of the area. This pattern will support periods of gentle to moderate south to southwest winds for the western half of the state, and light to moderate south to southeast winds throught the weekend. By next week Monday winds will have backed out of the east in moderate to fresh range as a more progressive systems develops northwest of the state.
Seas and surf will remain on the small side for all Hawaiian waters and shores as minimal swell energy expected through the rest of this week and into the weekend. The next notable short- to medium- period north swell is expected to arrive late this weekend. This swell will provide a boost in north facing shore surf and could build the seas to the 10 ft advisory level if it materializes early next week. South shores surf may see a boost in surf next week Tuesday through midweek.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov