West Side

Today: Mostly cloudy. Breezy. Frequent showers and slight chance of thunderstorms until late afternoon, then showers likely and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs around 77. South winds up to 15 mph increasing to up to 25 mph in the afternoon. Chance of rain 90 percent.

Tonight: Mostly cloudy. Breezy. Showers likely and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows 67 to 72. South winds 10 to 25 mph. Chance of rain 60 percent.

Saturday: Partly sunny with scattered showers. Highs around 78. South winds 10 to 15 mph shifting to the southwest in the afternoon. Chance of rain 50 percent.

South Side

Today: Mostly cloudy. Breezy. Frequent showers and slight chance of thunderstorms until late afternoon, then scattered showers and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs around 82. Light winds becoming southwest 10 to 25 mph in the afternoon. Chance of rain 80 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows 68 to 74. South winds 15 to 25 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs around 82. Southwest winds 10 to 15 mph decreasing to up to 10 mph in the afternoon. Chance of rain 40 percent.

North Shore

Today: Mostly cloudy. Frequent showers and slight chance of thunderstorms until late afternoon, then showers likely and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs around 79 near the shore to around 66 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Showers likely and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows around 71 near the shore to around 54 near 5000 feet. Southwest winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny with scattered showers. Highs around 80 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 50 percent.

Central Maui

Today: Mostly cloudy. Breezy. Frequent showers and slight chance of thunderstorms until late afternoon, then showers likely and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs around 81. Light winds becoming southwest up to 25 mph in the afternoon. Chance of rain 80 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows around 69. South winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs around 82. Southwest winds up to 15 mph. Chance of rain 40 percent.

Upcountry

Today: Very windy. Mostly cloudy with showers likely and slight chance of thunderstorms. Locally heavy rainfall possible. Highs around 61 at the visitor center to around 66 at the summit. South winds 10 to 40 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows around 50 at the visitor center to around 46 at the summit. Southwest winds 10 to 25 mph decreasing to up to 20 mph after midnight. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs around 62 at the visitor center to around 68 at the summit. Southwest winds up to 20 mph. Chance of rain 40 percent.

East Maui

Today: Mostly cloudy. Frequent showers and slight chance of thunderstorms until late afternoon, then showers likely and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs around 79 near the shore to around 66 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Showers likely and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows around 71 near the shore to around 54 near 5000 feet. Southwest winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny with scattered showers. Highs around 80 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 50 percent.

Lanai City

Today: Mostly cloudy. Breezy. Frequent showers and slight chance of thunderstorms until late afternoon, then showers likely and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs 69 to 77. South winds 10 to 25 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Breezy. Showers likely and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and early morning. Numerous showers early in the morning. Locally heavy rainfall possible early in the evening. Lows around 65. South winds 10 to 25 mph. Chance of rain 60 percent.

Saturday: Partly sunny. Scattered showers until late afternoon, then numerous showers late in the afternoon. Highs 71 to 77. South winds around 10 mph in the morning becoming light. Chance of rain 40 percent.

Kaunakakai

Today: Mostly cloudy. Breezy. Frequent showers and slight chance of thunderstorms until late afternoon, then showers likely and slight chance of thunderstorms late in the afternoon. Locally heavy rainfall possible. Highs 66 to 81. Southeast winds 10 to 20 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Breezy. Showers likely and slight chance of thunderstorms early in the evening, then scattered showers in the late evening and overnight. Locally heavy rainfall possible early in the evening. Lows 58 to 71. South winds 10 to 20 mph. Chance of rain 70 percent.

Saturday: Partly sunny with scattered showers. Highs 67 to 83. South winds up to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A low northwest of the state will swing east before lifting north today and be absorbed is a stronger, nearly stationary, low far northwest of the state. A front just west of Kauai associated with the low will move eastward pushing a broad band of showers eastward across the state through the day. Strong southerly winds ahead of the front will shift over Oahu this morning with light westerly winds filling in behind the front. Drier and lighter winds are expected to fill in across the state Saturday as the front pushes east of the state and weakens. Chance of showers will increase again across the state Sunday into early next week. Land/seabreezes will dominate much of the weather pattern next week as the low remains north of the state.

Discussion

Latest satellite imagery shows a low 500 sm northwest of Kauai early this morning with south to north orientated front just west of Kauai. A broad cloud shield remains over the the state. Radar light to moderate showers blanketed across the state with heavier showers building over Kauai early this morning. High resolution model guidance shows the frontal band moving east across the state today shifting the chances of heavier showers across Oahu later this morning and afternoon before moving onwards to Maui County tonight. Steady light to moderate showers will continue along the southeast Big Island. Thus the Flood Watch remains in effect for the state through this afternoon. The High Wind Warning (HWW) for windier areas of Kauai has been canceled as southerly winds eased and shifted more westerly. Strong southerly winds remain over Oahu which could still produce downsloping winds in areas north and downwind of steep terrain. However, the HWW for these winder areas has been downgraded to a Wind Advisory as overall wind speeds have weakened. As the front progresses towards the central island later this afternoon and evening wind speeds will continue to trend downward. Behind the front winds will ease to light and variable speeds. Big Island summits will continue to see advisory level winds through today before tapering off this afternoon thus the Wind Advisory remains in effect through this afternoon. The Winter Weather Advisory also remains in effect through this afternoon.
The low will become absorbed in a stronger, nearly stationary, low far northwest of the state Saturday. Remnant moisture lingering over the eastern half of the state will still produce some scattered showers but overall flooding threat will have decreased as low to mid level drier air filters in from the west to east across the state. An upper level shortwave is expected to dip southeastward Sunday, likely supporting another active weather period across the state that may extend through early next week. Winds will remain light through much of next week as this larger low slowly weakens through the first half of next week before shift northeast during the second half of next week. Light winds and lingering moisture will allow for afternoon sea breezes building clouds and increase showers over interior areas. Land breezes will develop overnight providing some clearing. This pattern is expected to persist through much of next week as this low keeps the island chain cut off from tradewinds returning.

Aviation

The threat of heavy rainfall will persist across the state today, which could lead to periods of MVFR to IFR VSBYS/CIGS along with gusty southerly winds. Conditions should gradually begin to improve over the western end of the state later today through tonight.
AIRMET Sierra is in effect for mountain obscuration above 020 ft for Kauai and Oahu. This will likely need to be expanded down the island chain later this morning, as showers expand eastward down the island chain.
AIRMET Tango remains in effect for moderate turbulence between FL180 and FL360 across the entire islands, and for moderate turbulence downwind of terrain for Oahu and Kauai.
AIRMET Zulu remains in effect for moderate icing between 140-FL200.

Marine

As the low pressure system to the northwest further deepens, we will likely see a few strong to severe thunderstorms capable of producing waterspouts and damaging winds over the coastal waters. Rough boating conditions are expected with elevated seas and strong to near gale force southerly winds. As such a Small Craft Advisory is in effect for all waters through at least 6PM.
Strong southerly winds are expected to slowly decrease west to east today. Surf along the southern shores is slowly declining. The High Surf Advisory has been cancelled as surf has fallen below criteria.
Along north facing shores, the current northwest (320 degree) swell is slowly decreasing and should dissipate to background levels on today. However a smaller short-period northwest swell generated by the aforementioned low will fill in tonight through early next week.
Surf along east facing shores could see an increase later this week due to the strengthening southeasterly winds especially for southeast exposures.

HFO Watches/Warnings/Advisories

Flood Watch through this afternoon for all Hawaii islands,
Wind Advisory until 6 PM HST this evening for Oahu North Shore, Olomana, Central Oahu, Waianae Mountains, Big Island Summits, Koolau Windward, Koolau Leeward.
Winter Weather Advisory until 6 PM HST this evening for Big Island Summits.
Small Craft Advisory until 6 PM HST this evening for all Hawaiian waters,

Data Courtesy of NOAA.gov