Hilo

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 78 to 83 near the shore to 66 to 72 at 4000 feet. South winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Haze. Lows 60 to 67 near the shore to 46 to 54 at 4000 feet. Southwest winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Thursday: Partly sunny with scattered showers. Haze. Highs around 81 near the shore to 65 to 72 at 4000 feet. South winds up to 15 mph. Chance of rain 30 percent.

Kona

Today: Sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Haze through the day. Highs around 84 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Haze. Lows 67 to 72 near the shore to 43 to 50 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny with scattered showers. Haze. Highs around 83 near the shore to around 66 near 5000 feet. Southwest winds up to 10 mph shifting to the west in the afternoon. Chance of rain 30 percent.

Waimea

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Haze in the late morning and afternoon. Highs around 79 near the shore to 70 to 76 near 3000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Haze. Lows 59 to 68 near the shore to 51 to 58 near 3000 feet. Light winds.

Thursday: Mostly sunny with scattered showers. Haze. Highs around 78 near the shore to 70 to 76 near 3000 feet. Light winds. Chance of rain 30 percent.

Kohala

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Haze in the late morning and afternoon. Highs around 79 near the shore to 70 to 76 near 3000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Haze. Lows 59 to 68 near the shore to 51 to 58 near 3000 feet. Light winds.

Thursday: Mostly sunny with scattered showers. Haze. Highs around 78 near the shore to 70 to 76 near 3000 feet. Light winds. Chance of rain 30 percent.

South Big Island

Today: Breezy. Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Haze through the day. Highs around 83 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Haze. Lows around 70 near the shore to around 48 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Thursday: Partly sunny with scattered showers. Haze. Highs around 83 near the shore to around 68 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 30 percent.

Puna

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 78 to 83 near the shore to 66 to 72 at 4000 feet. South winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Haze. Lows 60 to 67 near the shore to 46 to 54 at 4000 feet. Southwest winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Thursday: Partly sunny with scattered showers. Haze. Highs around 81 near the shore to 65 to 72 at 4000 feet. South winds up to 15 mph. Chance of rain 30 percent.

Waikoloa

Today: Mostly sunny early in the morning, then isolated showers in the late morning and afternoon. Haze through the day. Highs 81 to 86 near the shore to 63 to 70 above 4000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Haze. Lows 67 to 73 near the shore to 46 to 53 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with scattered showers. Haze. Highs 81 to 86 near the shore to 63 to 70 above 4000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Detailed Forecast

Synopsis

A cold front approaching from the northwest will bring increasing rainfall chances for portions of the state, with moderate south to southeast winds expected later today through the second half of the week. Drier conditions with light trades could return by the end of the weekend as the surface ridge briefly shifts northward. Another weakening cold front may approach and move into the area early next week.

Discussion

Guidance remains in good agreement, depicting a progressive pattern with a couple of cold fronts passing to the north. Deep- layer ridging over the state has resulted in light and variable winds, maintaining dry and stable conditions with a strong subsidence inversion positioned between 5,000 and 6,500 feet this morning, limiting rainfall chances. Any brief showers that form will favor windward coastal areas due to land breezes through the morning hours today.
A transition period is expected later today through the latter half of the week as the first cold front approaches. Low-level winds will veer from the east-southeast this morning to more of a southerly direction later today through tonight as the front nears. Increasing moisture and lift ahead of this boundary will enhance rainfall chances, particularly across leeward slopes and mountain areas in the western portion of the state. However, with the front likely stalling or hanging up near or north of Kauai, overall rainfall amounts should remain limited.
Although this pattern may persist into Saturday, a return to light to moderate trades and drier conditions is possible by the end of the weekend as the surface ridge briefly shifts northward. The second cold front passing far to the north on Sunday could drag the tail-end of its boundary into the western portion of the state early next week, bringing another potential increase in rain chances.

Aviation

Light to moderate SE-S winds. As a front approaches, winds will veer to the S-SW and increase in strength over Kauai and Oahu. Some SHRA and isol MVFR conds are possible but VFR conds should prevail.
No AIRMETs in effect and none are anticipated.

Marine

Light to moderate east-southeast winds will shift out of the south to southeast today, then linger through the second half of the week as a cold front approaches and stalls nearby to the north. Localized terrain-induced accelerations will support moderate to fresh speeds periodically in the typical areas with south to southeast winds. A return of light to moderate trades is possible by the end of the weekend.
A large northwest swell will peak through the day today, then subside tonight. Buoy 51101, roughly 200 nm west of Kauai, indicated a 13-14 foot, long period NW swell earlier this morning. To account for the swell height coming in several feet above guidance, the High Surf Advisory (HSA) has been upgraded to a High Surf Warning (HSW), which is now in effect for most north and west facing shores through late this afternoon. High surf conditions may continue into tonight for these shores, as the swell begins to subside. In addition, a HSA has been issued for west facing shores of the Big Island starting at noon today. A Small Craft Advisory (SCA) has been extended to account for hazardous seas across northwest waters exposed to the swell.
A large to extra large northwest swell is expected to build late Thursday into Friday, once again likely reaching High Surf Warning level for most north and west facing shores. The potential for overwash in low lying areas is possible as the swell peaks early Friday morning.
Surf along south facing shores will remain tiny with mainly background energy through the week. Surf along east facing shores will also remain tiny to small through the week due to mostly light background wind flow, with a potential slight uptick early next week with the return of the trade winds.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
High Surf Advisory from noon today to 6 AM HST Thursday for Kona, Kohala.
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.

Data Courtesy of NOAA.gov