West Side

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 82 to 87. Light winds. Chance of rain 40 percent.

Tonight: Mostly cloudy. Lows 69 to 77. Light winds becoming east up to 10 mph after midnight.

Saturday: Partly sunny. Highs 81 to 86. East winds 10 to 15 mph.

South Side

Today: Partly sunny. Isolated showers in the morning. Highs around 89. Southeast winds up to 10 mph shifting to the southwest around 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy. Lows 69 to 77. Light winds.

Saturday: Partly sunny. Highs around 90. Northeast winds around 10 mph.

North Shore

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 73 near the shore to around 53 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Central Maui

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 84 to 90. Southeast winds up to 10 mph shifting to the northeast around 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy. Lows 70 to 75. Southeast winds around 10 mph in the evening becoming light.

Saturday: Partly sunny. Highs 83 to 90. Northeast winds 10 to 15 mph.

Upcountry

Today: Mostly cloudy with scattered showers. Highs around 63 at the visitor center to around 67 at the summit. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 50 at the visitor center to around 47 at the summit. East winds up to 10 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Scattered showers in the morning. Highs around 64 at the visitor center to around 69 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

East Maui

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 73 near the shore to around 53 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Lanai City

Today: Mostly cloudy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 75 to 82. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening. Lows around 67. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Saturday: Partly sunny. Highs 74 to 82. Northeast winds around 10 mph.

Kaunakakai

Today: Mostly cloudy with numerous showers. Highs 75 to 91. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy. Scattered showers in the evening. Lows 60 to 75. East winds around 10 mph. Chance of rain 40 percent.

Saturday: Partly sunny. Isolated showers in the morning. Highs 73 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

An area of showery clouds south of Oahu will move northward today, and could bring a thunderstorm or to the waters south of Kauai and Oahu. Light wind flow will allow a land and sea breezes pattern to dominate with possible light trades building late this weekend. Winds shift out of the east-southeast next week with a wet and unstable pattern setting up over the islands by midweek.

Discussion

Have made some changes to the forecast both in the short and long term. Largely the changes bring the forecast in line with the latest National Blend of Models. In the short term, the main change was adding the chance for thunderstorms over the coastal waters south and west of Oahu today and into tonight, and to boost PoPs in that general area and over Oahu.
A low pressure system far north of Oahu, combined with its associated trough, will continue to bring a light wind flow pattern to the area through much of the weekend. As these features weaken later today and tomorrow, an uptick in winds is likely starting on the eastern end of the state and progressing westward. With the lighter winds, we likely continue to see land and sea breezes over the western end of the state, with some areas of of the eastern end also experiencing them.
An area of showery clouds south of Oahu is expected to move northward today, and there is the chance for a thunderstorm or two. Have added this to the forecast grids, but have limited the possiblity to the coastal waters only.
As mentioned above, as the low weakens, some moderate trade winds will filter back into the islands from south to north across the island chain, possibly late this weekend. An upper low digging southward, will position itself just west of the state by the middle of next week. The upper low will induce a surface trough that will veer and strengthen winds out of the east southeast beginning Monday night and continuing over the next several days after that, putting the islands in a relatively unstable and wet weather pattern. East southeast winds will focus clouds and scattered showers over windward and southeastern sides of the islands. Will be monitoring the model depiction of the event over the coming days for more specifics.

Aviation

Light south to southeast winds will continue today for the western half of the state while slightly stronger winds are likely for the eastern half. Expect land breezes this morning to give way to afternoon seabreezes over the western half of the state, and more sheltered areas for the eastern half by this afternono. An area of showery clouds south of Oahu are expected to move northward, and may be unstable enough to trigger a thunderstorm or two over the waters. Most sites will see VFR conditions, but MVFR and isolated IFR in showers is to be expected.
No AIRMETs in effect at this time. As mentioned above, depending on shower activity, AIRMET SIERRA may be needed.

Marine

A troughing pattern will continue to weaken trade winds near Hawaiian waters into early next week. An upper level disturbance lingering north of the island chain will bring periods of enhanced showers through the weekend. Weaker trade wind speeds will allow for daytime onshore sea breezes to continue along nearshore leeward coastal waters lasting into Saturday. Long range guidance shows increasing southeasterly winds by the middle of next week in an unstable weather pattern with the potential for increasing shower coverage and thunderstorms.
A mix of a small medium period northwest (330 deg) swell and a small, short period north northeast (020 deg) swell will maintain small surf along north facing shores through Saturday. The smaller forerunners of a moderate to large long period northwest (320 deg) swell will build into Hawaiian waters starting Sunday afternoon, this swell energy will continue to build overnight before peaking to High Surf Advisory (HSA) levels by Monday. The swell should hold at HSA levels through Tuesday before slowly decreasing below HSA levels from Wednesday onward. Predicting slightly higher swell heights than the latest swell model guidance indicates, as recent swell model forecasts were too low as compared to nearshore ground truth buoy observations.
Surf along south facing shores will remain small through the weekend with a series of background south and southwest swells. East facing shores will remain tiny to small through Friday. In addition, a small, medium to long period easterly swell from Tropical Cyclone Priscilla in the East Pacific is forecast to arrive late Saturday into Sunday.
Peak high tides associated with the lunar cycle will lead to minor coastal flooding along shorelines and low lying coastal areas during the peak high tide this morning. A Coastal Flood Statement remains in effect for all coastal areas today, and this statement will likely be cancelled later this morning following the peak high tide cycle.

Fire weather

Weak winds and continued isolated to scattered showers will help mitigate fire weather concerns for the next several days. Inversion heights across the state will range from as low as 5,000 to as high as 9,000 feet.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov