West Side

Tonight: Windy. Mostly cloudy with scattered showers. Lows 66 to 72. Northeast winds 20 to 30 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 82. Northeast winds 10 to 25 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

South Side

Tonight: Breezy. Partly cloudy with isolated showers. Lows 65 to 74. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 85. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy. Lows 64 to 74. North winds 10 to 15 mph.

North Shore

Tonight: Breezy. Cloudy with occasional showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Friday: Breezy. Cloudy with occasional showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 79 near the shore to around 64 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 80 percent.

Friday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Central Maui

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67. East winds 15 to 25 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny in the afternoon. Highs 78 to 85. Northeast winds 10 to 25 mph. Chance of rain 50 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows around 67. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Upcountry

Tonight: Mostly cloudy. Breezy. Occasional showers in the evening, then numerous showers after midnight. Lows around 44 at the visitor center to around 42 at the summit. East winds up to 25 mph. Chance of rain 90 percent.

Friday: Breezy. Mostly cloudy with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 59 at the visitor center to around 64 at the summit. East winds up to 25 mph. Chance of rain 50 percent.

Friday Night: Breezy. Partly cloudy with scattered showers. Lows around 45 at the visitor center to around 42 at the summit. Southeast winds 15 to 25 mph. Chance of rain 50 percent.

East Maui

Tonight: Breezy. Cloudy with occasional showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Friday: Breezy. Cloudy with occasional showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 79 near the shore to around 64 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 80 percent.

Friday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Lanai City

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows 61 to 66. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Breezy. Highs 71 to 79. Northeast winds 10 to 25 mph.

Friday Night: Partly cloudy. Lows around 64. Northeast winds 10 to 15 mph.

Kaunakakai

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 56 to 72. East winds 15 to 25 mph. Chance of rain 50 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 68 to 84. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Isolated showers. Lows 56 to 72. East winds 15 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to breezy trade winds will continue through early next week with clouds and showers generally favoring windward and mountain areas. Enhanced showers will be possible through tonight and again next week as moisture from a dissipated front moves in on the trades and a few upper-level disturbances move overhead. Lighter winds, thereafter, will be possible in the extended forecast.

Discussion

The latest observations show residual showers continuing to stream across the western islands, namely across Kauai and Oahu, as moderate to breezy trades are maintained. Expect showers and cloud cover to persist across windward and mountain areas, occasionally lingering toward the leeward areas.
A 1034mb high pressure ridge remains quasi-stationary well north of the islands and will begin to slowly propagate eastward over the next few days, maintaining the moderate to breezy trades across the region through Saturday, with decreasing shower trends from Saturday night through Monday, ahead of the ingress of a mid-level low just west of the islands, which will briefly increase instability.
A transition to wetter trades will begin by the middle of next week with the introduction of a cold frontal system moving into the Central Pacific basin from the northwest, pushing out the high pressure ridge north of the state. Latest model guidance is not in good agreement with the progression of the aforementioned cold frontal system, however, with some guidance suggesting winds may veer in a more east- southeasterly direction, leading to land and sea breezes expanding in coverage. Conversely, other guidance projects trades to remain the dominant feature through the outlook period.

Aviation

Moderate to breezy trade winds will continue for the next few days. Low cigs and SHRA should mainly impact windward and mauka locations. MVFR conds possible in heavier SHRA but VFR should prevail.
AIRMET Sierra is in effect for mtn obsc for north and east facing slopes of Kauai, Oahu, Molokai, and Maui.
AIRMET Tango will be canceled at next issuance.

Marine

Surface high pressure approximately 900 nautical miles far north northeast of Oahu will continue to advance east and settle northeast of the islands this weekend. This will produce a tight enough downstream pressure gradient to maintain fresh to locally strong trade winds the next several days. Widely scattered showers across the nearshore waters are in association with a band of higher moisture focused along the remnants of a surface boundary laying across the central waters. Enhanced easterlies will wash this shear line out through the evening. A Small Craft Advisory (SCA) remains in effect for the majority of the waters through Friday afternoon, with the exception of the leeward Maui and windward Big Island waters. A slightly weakened pressure gradient through the weekend will allow water-wide east trades to drop off a touch. SCA conditions will likely hang on for the typically windier waters surrounding Maui County and Big Island through early next week.
A fresh small, short to medium period northwest swell will produce chest to slightly above head high surf along north-facing shores through Friday morning. North surf will fall back to average waist to chest high heights by the weekend. A slightly larger northwest swell is expected to build in on Monday and decline Tuesday and Wednesday.
Evening surf cams showing fun size surf along Oahu's south shores evidence that today's reinforcing south southwest pulse is holding into the evening. This average waist to near head high surf should hold through Friday morning before beginning its afternoon decline. Typical small, long period background level surf will return this weekend. East wind wave chop may also work its way into more southern-facing shores through Friday.
Strong trade winds over and upstream of the islands will produce rough surf along eastern-facing exposures through Friday. The largest waves have been observed near Kauai, where buoys have been reporting near 10 foot significant wave heights this evening. These seas will peak overnight as Oahu and Kauai east-facing shore surf will come in just below High Surf Advisory thresholds. Along with stronger trades, elevated seas surrounding Kauai and Oahu will also warrant the SCA. Agitated east shore wind wave chop will begin to subside early next week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Friday for most Hawaiian waters.

Data Courtesy of NOAA.gov