West Side

Today: Sunny and windy. Highs 81 to 87. East winds 20 to 30 mph.

Tonight: Mostly clear. Breezy. Lows 69 to 76. Northeast winds 10 to 20 mph.

Saturday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 81 to 86. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

South Side

Today: Sunny and breezy. Highs around 90. Northeast winds up to 25 mph increasing to 10 to 25 mph in the afternoon.

Tonight: Mostly clear. Breezy. Lows 70 to 77. North winds 10 to 20 mph.

Saturday: Sunny and breezy. Highs around 89. North winds 10 to 25 mph.

North Shore

Today: Breezy. Partly sunny with scattered showers. Highs 80 to 86 near the shore to around 68 near 5000 feet. Southeast winds up to 25 mph shifting to the east 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 73 near the shore to around 54 near 5000 feet. East winds 15 to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 80 to 87 near the shore to around 67 near 5000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Central Maui

Today: Sunny and windy. Highs 82 to 90. East winds 10 to 30 mph.

Tonight: Mostly clear. Breezy. Lows 70 to 75. Northeast winds 15 to 20 mph.

Saturday: Sunny and breezy. Highs 81 to 89. Northeast winds 15 to 25 mph.

Upcountry

Today: Breezy. Mostly sunny with scattered showers. Highs around 67 at the visitor center to around 71 at the summit. East winds up to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 51 at the visitor center to around 48 at the summit. East winds 15 to 25 mph. Chance of rain 50 percent.

Saturday: Mostly sunny. Breezy. Scattered showers in the morning. Highs around 65 at the visitor center to around 70 at the summit. East winds 15 to 25 mph. Chance of rain 50 percent.

East Maui

Today: Breezy. Partly sunny with scattered showers. Highs 80 to 86 near the shore to around 68 near 5000 feet. Southeast winds up to 25 mph shifting to the east 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 73 near the shore to around 54 near 5000 feet. East winds 15 to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 80 to 87 near the shore to around 67 near 5000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Lanai City

Today: Sunny and breezy. Highs 74 to 83. Northeast winds 10 to 20 mph.

Tonight: Mostly clear. Lows 65 to 70. Northeast winds 10 to 15 mph.

Saturday: Sunny. Highs 74 to 83. East winds 10 to 15 mph.

Kaunakakai

Today: Sunny and breezy. Highs 74 to 90. East winds 10 to 25 mph increasing to 20 to 25 mph in the afternoon.

Tonight: Mostly clear. Breezy. Lows 62 to 75. East winds 10 to 20 mph.

Saturday: Mostly sunny. Breezy. Highs 74 to 90. East winds 10 to 20 mph.

Detailed Forecast

Synopsis

Breezy to locally windy trades, and rather dry and stable conditions will persist today, and likely into Saturday. Clouds and light showers will be focused over windward and mauka areas, while most leeward areas remain dry. Stable trade winds will gradually ease Sunday through Tuesday.

Discussion

No significant changes to the forecast or the forecast philosophy with the morning package.
High pressure to the northeast, along with Tropical Storm Iona and other low pressure to the south to southwest of the islands, combined with a stable airmass over the islands with the inversion around 6,000 feet, is continuing to tighten the pressure gradient over the islands leading to breezy to locally windy trade winds. Under these conditions, trades are being accelerated over and downwind of terrain, with winds strong enough to continue the Wind Advisory over portions of Maui County and the Big Island. Shallow pockets of moisture being carried in on the trade wind flow will continue to bring light rainfall accumulation mainly to windward slopes, with leeward areas remaining dry.
Little change is expected tonight and Saturday, so confidence is high that the Wind Advisory will be extended. The surface high northeast of the state will strengthen slightly as it drifts eastward, and a surface trough in the deep tropics will pass south of the islands, keeping the pressure gradient rather tight. Modest showers will remain confined to windward areas.
Trade winds will gradually decline Sunday into Tuesday as the high drifts eastward and the local pressure gradient slowly relaxes. The stable pattern of mainly windward and mauka showers should persist as little organized moisture is depicted in the guidance.
Some uncertainty is introduced by the middle of next week. The latest National Hurricane Center forecast depicts current east Pacific Tropical Storm Gil weakening to a remnant low well east of Hawaii early next week, and the GFS and ECMWF show a remnant circulation passing near the state around Wednesday or so. It's too early to determine what, if any effects, this feature will bring for island weather.

Aviation

High pressure to the northeast of the islands, combined with a low pressure system to the south, will maintain breezy to windy trade winds into the weekend. VFR conditions are expected to prevail, however some passing showers could bring brief MVFR conditions mainly to windward and mountain areas, especially overnight and in the early morning hours.
With little change expected with the winds today, no change to the AIRMETs. AIRMET Tango is in effect for moderate with isolated severe turbulence over and immediately S through W of the island mountains due to breezy trade winds, and reports yesterday of severe turbulence.

Marine

High pressure will remain far north of the state this weekend and help generate fresh to locally near gale trades across the local waters. A Small Craft Advisory (SCA) is currently in effect through tonight for most marine zones surrounding Maui and the Big Island. Additional zones may need to be added to the SCA this weekend as winds increase slightly. Trades then begin to weaken by early next week as the aforementioned high drifts further east.
Tropical Storm Iona continues to track to the west-northwest, far southwest of the main Hawaiian Islands.
The current moderate to large, long period, south swell appears to have peaked at the nearshore buoys, but is expected to hold steady through the afternoon and continue to bring advisory level surf to south facing shores. Thus, A High Surf Advisory remains in effect for the south facing shores of all islands through 6 PM HST. Expect a decline in swell energy tonight through this weekend as the swell slowly fades. Another moderate, long period, south swell should begin to build on Monday and help build surf heights to near advisory levels once again.
East shore surf will remain elevated and choppy due to locally strong trade winds through this weekend. This will be followed by a decline early next week as trades weaken.
Flat summer conditions along north facing shores may be interrupted late this weekend by a small long period northwest swell from Typhoon Krosa, currently in the western Pacific.

Fire weather

A gusty, stable, and rather dry trade wind flow will remain in place through today, and likely into Saturday. Critical fire weather conditions, with winds of 20 mph or more and daytime relative humidity of 35 to 45 percent, is expected to persist over leeward areas this afternoon, and possibly into Saturday. A strong inversion based around 6,000 feet will ensure that higher elevations of the Big Island and Haleakala on Maui experience very low relative humidity. Winds will decline Sunday into Tuesday, lowering fire weather concerns.

HFO Watches/Warnings/Advisories

Red Flag Warning until 6 PM HST this evening for Niihau, Kauai South, Kauai Southwest, East Honolulu, Honolulu Metro, Ewa Plain, Waianae Coast, Oahu North Shore, Central Oahu, Waianae Mountains, Molokai North, Molokai West, Molokai Leeward South, Lanai Windward, Lanai Leeward, Lanai South, Lanai Mauka, Kahoolawe, Maui Leeward West, Maui Central Valley North, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast, Kohala, Big Island Interior.
High Surf Advisory until 6 AM HST Saturday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, Kipahulu, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Wind Advisory until 6 PM HST this evening for Lanai Mauka, Kahoolawe, Kohala, Lanai Windward, Lanai Leeward, Maui Central Valley North, Maui Central Valley South, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 AM HST Saturday for Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov