West Side

Today: Windy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 77 to 83. Northeast winds 25 to 30 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Windy. Scattered showers in the evening, then isolated showers after midnight. Lows 68 to 75. Northeast winds 20 to 30 mph. Chance of rain 40 percent.

Friday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 78 to 83. Northeast winds 20 to 25 mph decreasing to 10 to 25 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Mostly sunny. Windy. Isolated showers in the afternoon. Highs around 86. Northeast winds 15 to 30 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows 68 to 76. Northeast winds 10 to 25 mph.

Friday: Sunny and breezy. Highs around 86. Northeast winds 10 to 20 mph.

North Shore

Today: Windy and showers. Highs around 80 near the shore to around 62 near 5000 feet. East winds 10 to 30 mph. Chance of rain near 100 percent.

Tonight: Windy and showers. Lows around 71 near the shore to around 52 near 5000 feet. East winds 10 to 30 mph decreasing to up to 25 mph after midnight. Chance of rain near 100 percent.

Friday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to around 62 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 70 percent.

Central Maui

Today: Windy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 86. Northeast winds 20 to 30 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Windy. Scattered showers in the evening, then isolated showers after midnight. Lows around 71. East winds 15 to 30 mph. Chance of rain 50 percent.

Friday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 79 to 86. East winds 10 to 25 mph. Chance of rain 20 percent.

Upcountry

Today: Partly sunny. Windy. Showers in the morning, then scattered showers in the afternoon. Highs around 57 at the visitor center to around 65 at the summit. East winds 15 to 30 mph with gusts to 50 mph. Chance of rain 90 percent.

Tonight: Windy. Showers in the evening, then scattered showers after midnight. Lows around 47 at the visitor center to around 44 at the summit. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain near 100 percent.

Friday: Breezy. Mostly sunny with scattered showers. Highs around 58 at the visitor center to around 65 at the summit. East winds up to 25 mph. Chance of rain 50 percent.

East Maui

Today: Windy and showers. Highs around 80 near the shore to around 62 near 5000 feet. East winds 10 to 30 mph. Chance of rain near 100 percent.

Tonight: Windy and showers. Lows around 71 near the shore to around 52 near 5000 feet. East winds 10 to 30 mph decreasing to up to 25 mph after midnight. Chance of rain near 100 percent.

Friday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to around 62 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 70 percent.

Lanai City

Today: Windy. Mostly sunny with isolated showers. Highs 71 to 80. Northeast winds 20 to 30 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Windy. Isolated showers in the evening. Lows 64 to 69. Northeast winds 10 to 30 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Breezy. Highs 71 to 80. Northeast winds 10 to 25 mph.

Kaunakakai

Today: Windy. Mostly sunny with isolated showers. Highs 69 to 86. Northeast winds 20 to 30 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 59 to 74. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 70 to 86. East winds 15 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A broad high remains the dominant feature for much of the Central Pacific and will aid in maintaining breezy to windy trades across the Hawaiian Islands through this evening. Enhanced shower activity and cloud coverage will persist, namely for windward and mauka areas. Trades will begin to weaken to a more moderate regime by Friday in response to the high weakening and propagating eastward away from the Hawaiian Islands.

Discussion

The latest surface analysis displays a broad 1034 mb area of high pressure well north of the Hawaiian Islands, still maintaining relatively breezy to windy trades across the islands. Latest model guidance suggests that the trades will be somewhat similar today as they were the previous 24 hours, especially over the Kohala District on the Big Island, where the strongest winds have been noted so far.
Because of this, opted to extend the current Wind Advisory for portions of Maui County and the Big Island through 04z Friday (0600 PM Thursday). Model guidance highlights winds will gradually ease thereafter, becoming a more moderate to locally breezy regime, and fall outside of advisory criteria.
Simultaneously, radar and satellite imagery continues to showcase enhanced showers propagating into windward and mauka areas, namely for the southern islands including Maui County and the Big Island. CIMSS MIMIC precipitable water (PWATs) continue to show additional areas of moisture embedded in the trades upstream of the islands. This will keep windward and mauka showers going through the week, with a few showers likely spilling over into leeward areas during the overnight and early morning hours. Shower activity looks to gradually taper off over the weekend as a drier and more stable air mass briefly moves into the area.
The latest guidance for the forecast early next week is largely unchanged from the past few days. Model guidance of the GFS continues to show a surface trough producing southerly flow propagate across the islands, escorting an abundance of tropical moisture with it around Monday or Tuesday of next week. If this proves fruitful, it could lead to a period of moderate to heavy rainfall — on the order of 3 to 4 standard deviations above normal for total precipitable water. Conversely, model guidance of the ECMWF depicts tropical moisture remaining just south of the state, negating the heavy rainfall threat. Both models do show a depiction of a cold front advancing southward in the vicinity of the Hawaiian Islands through the first half of the week. Given the vast differences between the two models, there is no obvious outcome generating quite a fair bit of uncertainty going forward. Further analysis on model trends over the next several days will be required to determine which model will become the favored scenario.

Aviation

Broad surface high pressure north of the islands will aid in breezy to windy trades persisting through much of today. Clouds and shower activity associated with these trades will bring periods of MVFR conditions, namely for windward and mauka areas. Otherwise VFR conditions prevail.
AIRMET Sierra will continue for mountain obscuration across all islands through at least this evening.
AIRMET Tango will continue for turbulence over and downwind of terrain below 10,000 feet. AIRMET Tango will also continue for 30 kt or greater sustained winds between Oahu and Big Island.

Marine

A strong surface high north-northeast of the islands, is driving fresh to locally gale force trade winds across Hawaiian waters. The high will sag southeast toward 30N and weaken slightly today which will shift winds to a more easterly direction. The Gale Warning has been extended through this afternoon for the Alenuihaha Channel, as wind speeds are still expected to maintain their strength. Elsewhere, a Small Craft Advisory (SCA) remains in effect for a combination of winds and seas. Some zones may drop out of the SCA tonight as winds and seas ease for leeward zones around Kauai and Oahu. The high pressure will meander northeast of the state near 30N tonight into early next week while gradually weakening. Trade winds are expected to ease to moderate to locally strong speeds overnight and Friday then possibly to more gentle to fresh speeds over the weekend. A front approaching from the northwest early next week could veer the winds out of the southeast with winds weakening to more light to moderate levels. GFS is more progressive with the front and impacts than the EC thus confidence in the extended forecast is low.
The current short period northeasterly (030 to 050 degree) swell will gradually decline today through Friday. The High Surf Advisory (HSA) remains in effect through this afternoon. Offshore buoy 51000 is still showing plenty of energy that may likely keep surf elevated along east facing shores through tonight but holding off extending HSA at this time and will continue to monitor all available data and make a determination later today. Rough, choppy east shore surf will continue to gradually decline through the weekend as local and upstream trade winds speeds ease. Meanwhile, a small to moderate long period northwest swell that peaked last night will gradually decline today. Another small, long period, northwest swell will fill in over the weekend which should provide a small uptick in surf along north and west facing shores.
A small, long period, south swell that peaked yesterday will slowly fade today and Friday. Small background south and southwest swells will fill in over the weekend keeping surf along south from going flat.

Fire weather

Breezy to windy trades will continue through this afternoon, becoming moderate to breezy before the weekend. Low-level moisture embedded in the trades should help to maintain relative humidity above critical fire weather thresholds. Temperature inversion heights near the Big Island and Maui will range from 9,000 to 10,000 feet today.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Olomana, Maui Windward West, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, Big Island East, Big Island North.
Wind Advisory until 6 PM HST this evening for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Interior, Lanai Windward, Lanai Leeward, Maui Central Valley North, Maui Central Valley South, South Haleakala, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Gale Warning until 6 PM HST this evening for Alenuihaha Channel.

Data Courtesy of NOAA.gov