Photo Credit: Allen Tate

West Side

Today: Sunny, with a high near 83. Light and variable wind becoming southwest 5 to 7 mph in the afternoon.

Tonight: Isolated showers. Partly cloudy, with a low around 67. Southwest wind 7 to 9 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers. Mostly sunny, with a high near 83. West southwest wind 7 to 9 mph becoming north northeast in the afternoon. Chance of precipitation is 20%.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 83. Light and variable wind becoming west 5 to 7 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 65. Light west southwest wind increasing to 5 to 10 mph after midnight. Chance of precipitation is 20%.

Wednesday: Scattered showers. Partly sunny, with a high near 83. West wind around 7 mph becoming north northeast in the afternoon. Chance of precipitation is 30%.

North Shore

Today: Isolated showers. Mostly sunny, with a high near 81. Light and variable wind becoming east around 5 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 66. Light south southwest wind becoming southwest 5 to 9 mph after midnight. Chance of precipitation is 20%.

Wednesday: Isolated showers. Mostly sunny, with a high near 81. West southwest wind around 8 mph becoming north in the afternoon. Chance of precipitation is 20%.

Central Maui

Today: Isolated showers after 1pm. Mostly sunny, with a high near 81. Light and variable wind becoming north northeast around 5 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before 7pm. Partly cloudy, with a low around 64. South southwest wind 6 to 9 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers after 7am. Mostly sunny, with a high near 81. West southwest wind around 7 mph. Chance of precipitation is 20%.

Upcountry

Today: Isolated showers after 1pm. Mostly sunny, with a high near 69. Light and variable wind becoming west 5 to 8 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers before 7pm. Partly cloudy, with a low around 54. West southwest wind 6 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

Wednesday: Scattered showers after 7am. Mostly sunny, with a high near 69. West southwest wind 8 to 11 mph. Chance of precipitation is 30%.

East Maui

Today: Scattered showers. Partly sunny, with a high near 79. Southeast wind 6 to 13 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 7pm. Mostly cloudy, with a low around 62. South southeast wind around 6 mph becoming light and variable after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Isolated showers. Partly sunny, with a high near 79. West southwest wind around 6 mph. Chance of precipitation is 20%.

Lanai City

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 75. Light and variable wind becoming southwest 5 to 10 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 63. West southwest wind 10 to 13 mph. Chance of precipitation is 20%.

Wednesday: Scattered showers. Partly sunny, with a high near 74. West southwest wind 9 to 13 mph becoming north northeast in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kaunakakai

Today: Sunny, with a high near 81. Light and variable wind.

Tonight: Isolated showers after 7pm. Partly cloudy, with a low around 67. Southwest wind 9 to 11 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers. Mostly sunny, with a high near 80. West southwest wind 9 to 13 mph. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

Winds will weaken today, allowing development of afternoon seabreezes and interior clouds. Showers will increase Wednesday and Thursday as a front reaches the islands and dissipates. Trade winds will return and strengthen as the front dissipates. However, winds will diminish again late in the week as another front approaches, bringing the possibility of inclement weather late in the weekend.

Discussion

The proximity of a ridge just north of the main Hawaiian Islands has caused winds across local waters to become light this morning. Overnight soundings show a rather dry and stable airmass, with PW around 1.1 inches with positive lifted index values. A capping inversion is noted around 7000 feet. Through today, winds will veer to southeasterlies as a front approaches from the northwest, placing the smaller islands in the wind shadow of the Big Island. Expect afternoon seabreezes across leeward locations, with limited interior showers and cloud buildups. Trade wind weather will remain for the Big Island and windward areas of Maui. Winds will swing to southwesterlies tonight and then to westerlies as the weakening front reaches Kauai sometime Wednesday. The front is forecast to dissipate Wednesday night into Thursday, but remaining frontal moisture will bring increasing showers and cloud cover as winds flip back to northeasterly trades Thursday.
Another front is forecast to veer winds to southeasterlies Thursday night, with widespread seabreezes expected again Friday and Saturday afternoons. Models stall the front northwest of Kauai through Saturday before another reinforcing front pushes toward Kauai on Sunday. This has the potential to bring widespread rain late Sunday and into next week.

Aviation

A front approaching the region from the northwest will push a weak surface ridge, which is currently located just north of the state, closer to the islands later today. This will cause the background flow to gradually weaken and shift from an east- southeast to southeast direction. The low-level flow is transporting clouds and light showers across east through southeast facing coasts and slopes of some of the islands early this morning. This may cause brief periods of MVFR ceilings and visibilities over some windward sections into mid-morning. Otherwise, VFR conditions will likely prevail across most of the state this morning.
The light background winds will allow local sea breezes to become established over interior / leeward sections of the individual island by this afternoon. This may cause clouds and isolated showers to develop over interior sections of some of the islands, which might result in localized brief periods of MVFR conditions over interior terrain. The background winds are expected to shift around out of the south and southwest ahead of the approaching front later tonight. Expect increasing cloud cover and showers to develop ahead of this front from later tonight through early Wednesday.
No AIRMETS are currently in effect, and none are anticipated through this afternoon. Later tonight, increasing clouds and showers may eventually require SIGMET Sierra for mountain obscuration as low clouds and showers increase in coverage over the western end of the island chain (especially Kauai) ahead of the front.

Marine

A cold front will approach from the west today and tonight, move into the marine area Wednesday, then stall out and dissipate over the waters Wednesday night and Thursday. High pressure will briefly build north of the area Thursday, with the next cold front then approaching from the west Friday through Saturday. Winds are expected to remain below Small Craft Advisory thresholds through the period, although a series of large northwest swells will lift seas above the 10 foot advisory threshold at times.
The latest buoy observations over the nearshore and offshore waters indicate that the current northwest swell is a bit below predicted levels. As a result, only marginal advisory level surf is expected along north facing shores of most of the smaller islands, while surf should hold below advisory thresholds along west facing shores. A High Surf Advisory (HSA) remains in effect for north facing shores of Niihau, Kauai, Oahu Molokai and Maui through 6 PM HST this evening.
A much larger northwest swell is expected to arrive Wednesday night, peak on Thursday, then lower gradually Thursday night and Friday. Model guidance indicates warning level surf during the peak of this swell. An even larger northwest swell is on tap for the weekend with warning level surf expected once again.
A combination of large surf this week coinciding with peak monthly high tides will worsen beach erosion issues for shores exposed to north and northwest swells. Additionally, vulnerable low lying locations not exposed to the large swells may experience nuisance flooding at and around the peak daily tide cycles this week (between midnight and daybreak).
Short period surf along east facing shores will remain small through the week and over the weekend due to the lack of trade winds upstream of the state. Surf along south facing shores will remain small through the week, although a bit of a boost is expected from a small south-southwest swell Wednesday through Thursday, and from a south-southeast swell over the weekend.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Windward, Oahu North Shore, Oahu Koolau, Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala.

Data Courtesy of NOAA.gov