Photo Credit: Joan M. Flake

West Side

Today: Isolated showers after noon. Partly sunny, with a high near 83. West southwest wind around 5 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 65. Calm wind. Chance of precipitation is 20%.

Sunday: Sunny, with a high near 83. Calm wind becoming east 5 to 7 mph in the afternoon.

South Side

Today: Scattered showers after noon. Partly sunny, with a high near 83. Northeast wind around 5 mph becoming calm in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 8pm. Partly cloudy, with a low around 63. Light and variable wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Isolated showers after noon. Mostly sunny, with a high near 83. Light and variable wind becoming northeast 5 to 10 mph in the morning. Chance of precipitation is 20%.

North Shore

Today: Scattered showers after 1pm. Partly sunny, with a high near 81. Light and variable wind becoming northeast 9 to 14 mph in the afternoon. Winds could gust as high as 18 mph. Chance of precipitation is 30%.

Tonight: Scattered showers, mainly before 9pm. Mostly cloudy, with a low around 64. East wind 5 to 11 mph becoming south southeast after midnight. Chance of precipitation is 30%.

Sunday: Isolated showers before 1pm. Mostly sunny, with a high near 81. Breezy, with a light and variable wind becoming east northeast 12 to 17 mph in the afternoon. Winds could gust as high as 24 mph. Chance of precipitation is 20%.

Central Maui

Today: Isolated showers after 1pm. Partly sunny, with a high near 81. Southwest wind 6 to 10 mph becoming northeast in the morning. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 62. Northeast wind 5 to 9 mph becoming light and variable after midnight. Chance of precipitation is 20%.

Sunday: Isolated showers before 1pm. Mostly sunny, with a high near 81. Breezy, with a northwest wind 6 to 11 mph becoming northeast 13 to 18 mph in the afternoon. Winds could gust as high as 25 mph. Chance of precipitation is 20%.

Upcountry

Today: Scattered showers after noon. Partly sunny, with a high near 70. Calm wind becoming west around 6 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 8pm. Partly cloudy, with a low around 52. Calm wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Mostly sunny, with a high near 69. Light and variable wind becoming east 6 to 11 mph in the morning.

East Maui

Today: Scattered showers. Partly sunny, with a high near 79. Calm wind becoming east 5 to 7 mph in the morning. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 60. East southeast wind around 6 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers. Partly sunny, with a high near 79. East southeast wind 5 to 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Scattered showers after noon. Mostly cloudy, with a high near 75. Light and variable wind becoming northeast 5 to 10 mph in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 8pm. Partly cloudy, with a low around 62. Northeast wind 5 to 10 mph becoming light and variable in the evening. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Isolated showers. Mostly sunny, with a high near 75. Calm wind becoming east 5 to 7 mph in the afternoon. Chance of precipitation is 20%.

Kaunakakai

Today: Isolated showers after noon. Partly sunny, with a high near 80. North wind 5 to 8 mph becoming south southeast in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 66. East wind 5 to 8 mph becoming calm in the evening. Chance of precipitation is 20%.

Sunday: Sunny, with a high near 80. Breezy, with a light and variable wind becoming east southeast 10 to 15 mph in the morning. Winds could gust as high as 21 mph.

Detailed Forecast

Synopsis

Light winds will prevail today as a diminishing front and upper disturbance move into the area. Although mostly dry conditions will remain in place for most areas, a few showers near and along this front will be possible around Kauai and over the Big Island where the upper disturbance sets up later today through Sunday. Light to moderate easterly trades will return briefly Sunday into Monday, then diminish once again Tuesday as a front approaches and moves into the area around midweek.

Discussion

Latest surface analysis showed the ridge over the islands and the tail-end of a cold front nearby to the north. This has led to the trades collapsing locally, giving way to light and variable winds. This frontal boundary inching southward into the area combined with lowering upper heights as an upper trough moves into the area may support an increase in shower coverage today over and around Kauai. The added instability associated with this upper feature setting up over the eastern end of the state later this afternoon into tonight may trigger localized heavy afternoon/evening showers over the Big Island slopes with the sea breezes.
Trade winds will make a brief comeback on Sunday and Monday. A weak surface ridge will become reestablished north of the state as the front near Kauai dissipates. A ridge aloft will build over the northern end of the island chain while an upper-level low develops along the upper trough to the south of the Big Island. As a result, the Big Island could see an enhancement of showers, while the rest of the state experiences a typical trade wind regime with limited showers over mainly windward slopes.
Trade winds will break down and shift southerly on Tuesday, potentially followed by a frontal passage late Wednesday and Thursday. Fairly dry conditions are likely on Tuesday and Wednesday ahead of the front. Though there is considerable uncertainty this far out, the GFS and ECMWF show a shallow band of showers reaching Kauai late Wednesday and stalling near Maui as northeasterly trades build on Thursday. Forecast models suggest that another approaching front will disrupt the trades on Friday.

Aviation

A weakening front located just north of Kauai will keep a weak surface ridge in the vicinity of the islands this morning. The proximity of these features is producing light background winds across the state this morning. Local nighttime land breeze circulations are currently across each of the individual islands. Stable and reactively dry atmospheric conditions remain across the region early this morning due to a mid-level ridge, which is nosing in from the west. Scattered to locally broken low clouds and isolated light showers are evident along windward facing slopes and coastal sections of the Big Island, Maui, and Molokai. These may produce brief periods of MVFR conditions over northeast through southeast sections of these islands this morning.
By this afternoon, expect local sea breezes to develop over the state. A upper-level trough is digging down toward the eastern end of the island chain from the north-northwest. The arrival of this new feature may result in less stable atmospheric conditions over parts of the state later today and tonight. Some of the moisture from the weakening front may be close enough to cause a slight increase in low clouds and showers over northeast and interior sections of Kauai. There may also be widespread cloud cover and locally heavy showers over the interior of the Big Island due to the less stable conditions associated with the upper-level trough. Elsewhere, low clouds and showers may develop over the interior sections of the islands from Maui to Oahu. There is a possibility of brief localized MVFR conditions over some interior areas, such as the Big Island, this afternoon. Otherwise, expect VFR conditions to prevail elsewhere across the state into this evening.
Finally, AIRMET Tango has been issued for moderate turbulence aloft above the islands in the layer between 25,000 and 40,000 feet. This AIRMET will likely be needed through this afternoon. No additional AIRMETs are anticipated through this evening.

Marine

A ridge lingering near the state will maintain light winds across the waters today. Light to moderate trade winds are expected to return from east to west across the marine area tonight and Sunday, then hold at these levels through Monday. The trades will become disrupted again on Tuesday as a front approaches from the west, with winds easing and shifting around to the southeast and south. South to southwest winds will pick up to moderate and locally fresh levels Tuesday night and Wednesday in advance of the front, then shift around to the north and northeast at moderate to fresh levels in its wake. Winds are expected to remain below Small Craft Advisory (SCA) thresholds through the middle of next week. Seas will build to SCA levels as a new large north- northwest swell arrives today. A series of large overlapping north and northwest swells will keep seas at or close to SCA levels through the middle of next week.
A new north-northwest swell will build quickly through the afternoon, with surf reaching advisory thresholds along exposed north and west facing shores. As a result, a High Surf Advisory is in effect beginning at noon for exposed north and west facing shores of the smaller islands. The advisory will likely need to be expanded to include north facing shores of the Big Island tonight. Advisory level surf is expected to hold in place across most north and west facing shores through Sunday, before declining below advisory levels Sunday night. Surf could rise back above advisory levels along most north and west facing shores as early as Monday afternoon, as a new northwest swell arrives and hold at advisory levels into Tuesday night. After another brief drop below advisory levels on Wednesday, a new large northwest swell will likely bring advisory level surf to north and west facing shores Wednesday night through Friday, with the potential for warning level surf on Thursday.
Surf along east facing shores will remain small through next week due to a lack of trade winds over and upstream of the islands. The one exception will be for areas with a northern exposure. Surf along south facing shores will remain small through next week with mainly background energy moving through. A small south- southwest swell may give a small boost to south shore surf around the middle of next week.

HFO Watches/Warnings/Advisories

High Surf Advisory from noon today to 6 PM HST Sunday for Niihau, Kauai Windward, Kauai Leeward, Waianae Coast, Oahu North Shore, Oahu Koolau, Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala.
Small Craft Advisory from noon today to 6 PM HST Sunday for Kauai Northwest Waters, Kauai Windward Waters, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Alenuihaha Channel, Big Island Windward Waters.

Data Courtesy of NOAA.gov