Photo Credit: Brendan Stephen

West Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 86 to 92 near the shore to around 78 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Lows around 72 near the shore to around 62 above 3000 feet. East winds 10 to 15 mph.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 87 to 92 near the shore to around 79 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 84 to 91. East winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 73. East winds 15 to 25 mph. Chance of rain 40 percent.

Tuesday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 85 to 91. East winds 15 to 25 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 85 in the valleys to around 68 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 69 in the valleys to around 60 above 4000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs 75 to 85 in the valleys to around 68 above 4000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 77 to 89. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 66 to 74. East winds 10 to 20 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 89. East winds 10 to 20 mph. Chance of rain 40 percent.

East Kaua’i

Today: Breezy. Mostly cloudy with scattered showers. Highs 74 to 88. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 66 to 78. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 88. East winds 10 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Locally breezy trade winds will prevail into the weekend. Expect limited windward showers, mainly during the overnight through early morning hours each day. Leeward areas will stay mostly dry with the exception of the Kona slopes of the Big Island, which will see typical cloud buildups and a few showers possible each afternoon through evening.

Discussion

No significant changes to the forecast with the morning package. Have trended the PoPs and associated fields to the latest National Blend of Models, but little change was noted. High pressure remains to the far north of the area, and is expected to remain in place for much of the week.
The high to the north will continue to drive locally breezy trade winds to the region into the weekend. The overnight soundings from Lihue and Hilo show the trade wind inversion has risen a bit to 8000 and 9000 feet respectively, and precipitable water (PW) has risen to 1.3 inches. Satellite derived PW shows a narrow area of PW corresponding to these higher values near the islands at 3am, but shows drier air about 20 miles upstream. These small fluctuations are expected to continue through the week and will at times mean a few more clouds and showers riding in on the trades.
The GFS and ECMWF show an upper level trough digging southward to the east of the islands during the second half of the week. This could mean an increase in a few showers riding in on the trade winds. With that being said, little change is expected in the forecast through the week.

Aviation

High pressure located north of the islands will maintain moderate to locally breezy trade winds for the next several days. AIRMET Tango remains in effect for moderate low-level turbulence downwind of island terrain, and this AIRMET will likely be needed throughout the next 24 hours and beyond.
Clouds and showers will generally favor north through southeast sections of the islands, especially during the overnight through morning hours each day. While VFR conditions are expected to prevail at most locations, occasional MVFR ceilings and visibilities will be possible within passing showers. Additionally, latest satellite imagery early this morning shows a band of moisture upstream of the smaller islands that could increase low clouds and shower coverage across windward areas later this morning.

Marine

A high pressure ridge north of Hawaii will keep trade winds blowing across the region in the fresh to locally strong range today, then slightly strengthen tonight into Tuesday. Small Craft Advisory (SCA) remains in effect for the windier waters around Maui and Hawaii Counties. A slight increase in trade wind speed may require an expansion of the SCA to other marine zones, such as the Kaiwi Channel by Tuesday.
Surf along south facing shores will trend up today as a long period southwest (210-220 degree) swell energy from the Tasman Sea arrives and begins to move through the area. This southwest swell should peak around Tuesday and will be followed by a small reinforcing south-southwest (200-220 degree) swell by Wednesday. The combination of these swells should produce small surf along south facing shores through the week.
Surf along east facing shores will remain rough and choppy each day due to the persistent fresh onshore breezes.
As we head into August, water levels are running higher than predicted (0.3 to 0.6 ft) statewide due to a combination of our peak annual tides and a sea level anomaly moving through the region. These higher water levels will lead to minor coastal flooding each afternoon around the peak daily high tides through Wednesday for the typical vulnerable low lying coastal areas and beaches. Observations on Sunday afternoon showed a preliminary observation of 2.9 ft at the Honolulu tide gauge which is a little over 0.3 feet higher than the predicted tide. See the latest Coastal Flood Statement (product CFWHFO) for more details.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov