West Side

Today: Mostly sunny. Highs 83 to 88. Southeast winds up to 10 mph shifting to the west in the afternoon.

Tonight: Mostly clear. Lows 69 to 77. East winds up to 15 mph.

Friday: Sunny. Highs 81 to 87. East winds 10 to 15 mph.

South Side

Today: Sunny and breezy. Highs around 90. North winds up to 15 mph shifting to the northwest up to 25 mph in the afternoon.

Tonight: Mostly clear. Breezy. Lows 71 to 77. Northeast winds up to 25 mph shifting to the north up to 15 mph after midnight.

Friday: Sunny. Highs around 90. North winds 10 to 15 mph.

North Shore

Today: Breezy. Partly sunny with scattered showers. Highs 81 to 87 near the shore to around 70 near 5000 feet. East winds up to 25 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 74 near the shore to around 54 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Friday: Sunny. Highs 81 to 88 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph.

Central Maui

Today: Mostly sunny. Breezy. Highs 84 to 91. East winds up to 20 mph shifting to the northeast 10 to 20 mph in the afternoon.

Tonight: Mostly clear. Breezy. Lows around 72. Northeast winds up to 20 mph.

Friday: Sunny. Highs 82 to 90. Northeast winds 10 to 15 mph.

Upcountry

Today: Breezy. Sunny with isolated showers. Highs 63 to 73. East winds up to 25 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows around 53 at the visitor center to around 49 at the summit. East winds up to 25 mph.

Friday: Sunny and breezy. Highs around 69 at the visitor center to around 71 at the summit. East winds 10 to 20 mph.

East Maui

Today: Breezy. Partly sunny with scattered showers. Highs 81 to 87 near the shore to around 70 near 5000 feet. East winds up to 25 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 74 near the shore to around 54 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Friday: Sunny. Highs 81 to 88 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph.

Lanai City

Today: Breezy. Mostly sunny with isolated showers. Highs 76 to 84. West winds up to 10 mph shifting to the northeast up to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows 65 to 70. Northeast winds up to 25 mph shifting to the east up to 10 mph after midnight.

Friday: Sunny. Highs 75 to 83. East winds around 10 mph.

Kaunakakai

Today: Breezy. Mostly sunny with isolated showers. Highs 76 to 91. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows 62 to 77. East winds up to 20 mph.

Friday: Sunny and breezy. Highs 75 to 91. East winds 15 to 20 mph.

Detailed Forecast

Synopsis

Trade winds will return to the islands today, a bit earlier than originally expected, drier humidity trends will follow and last through Saturday. Brief passing showers are expected to develop over windward mountain areas. Tropical Storm Henriette will also continue drifting westward, passing just north of the islands from Sunday through Monday. This next system will produce similar lighter hybrid sea breeze and trade winds, increasing shower trends over island interior sections, with very warm and humid conditions lasting into Monday. Trade winds begin to transition back into the islands with decreasing humidity trends and a more typically stable trade wind weather pattern from Monday afternoon onward.

Discussion

The satellite picture this morning shows a north to south cloud band associated with wind convergence between the lighter winds over the islands and the returning trade winds. Trade winds are returning a bit sooner than we had in the forecast 24 hours ago. Drier conditions will move in with the returning trades and local relative humidity will drop back to normal summertime levels. Subsidence temperature inversion heights will drop to around the 5,000 foot elevation level, keeping shower activity to a minimum favoring the windward mountain areas through Saturday. Brief periods of high level cirrus clouds may enhance island sunrise and sunset colors through the week.
The most recent volcanic eruption from Kilauea on the Big Island is producing some VOG (Volcanic smOG) at local air quality sensors mainly along the southern and Kona slopes of the Big Island this morning. Sea breezes along the Kona slopes each day may mix this VOG as far north as Waimea town. The returning easterly trade winds will likely keep much of the VOG concentrations away from the smaller islands through Saturday. A portion of this VOG plume may possibly drift northward into the smaller islands if emissions continue by Sunday as the trade winds diminish.
Medium range global models and National Hurricane Center forecasts continue to show Tropical Storm Henriette passing just north of the islands from Sunday through Monday, once again disrupting trade winds, enhancing leeward and interior island shower activity, and producing warm and very humid weather. Moderate trade winds with drier trends develop from late Monday onward, with more typical summer weather conditions lasting through the end of next week.

Aviation

Trade winds return today as onshore sea breezes retreat to the more terrain sheltered western slopes of each island. Clouds and brief passing showers will return to windward and mountain areas, favoring the overnight to early morning hours.
No AIRMETs in effect.

Marine

Trade winds will strengthen today in the wake of a weak trough passage into the northwest offshore waters. A Small Craft Advisory is in effect through late tonight for locally strong trades across the windier waters surrounding Maui County and Big Island. High pressure far northeast of the state will drift to the north over the weekend as Tropical Storm Henriette approaches the region from the east. Henriette will take a similar path as Gil and this will weaken the pressure gradient back to the high, resulting in weaker weekend trades. Henriette will be far north of the northern Hawaiian offshore waters early next week.
Long period forerunners from the next south swell are delayed but should be entering our waters later today and build in tonight. A large reinforcing southern impulse will arrive late Friday through early Saturday and peak south swell going into the weekend. South- facing surf will reach High Surf Advisory levels by Friday with heights nearing High Surf Warning thresholds Saturday.
Eastern exposure surf has fallen a bit with the passage of an eastern fetch from Gil and lighter trades. Strengthening trades will allow eastern chop to lift back to near seasonal averages later today into tonight. A captured east swell from Tropical Storm Henriette will likely arrive this weekend, increasing east surf by another foot or so.
A very small northwest swell passing through today will keep north surf from going completely flat.
Peak afternoon high tides, combined with elevated water levels running about a half a foot higher than predicted and a large south swell, will lead to minor flooding along many south-facing shorelines and low lying coastal areas through Saturday. Water levels should fall below thresholds during peak afternoon high tides Sunday.

Fire weather

Trade winds return to the islands today with elevated humidity levels for this time of year will decrease through Saturday as drier air moves back into the Hawaii Region. Another round of deep tropical moisture in a hybrid trade wind sea breeze pattern will sweep through the islands from Sunday into Monday as Henriette follows a similar path. Moderate trade winds will begin to build back into the state from late Monday into Wednesday with drier and more stable weather in the long range forecast. Temperature inversion heights near Maui and the Big Island today will range from 4,500 to 5,500 feet.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov