West Side

Today: Sunny. Highs 82 to 87. East winds up to 15 mph.

Tonight: Mostly clear. Lows 68 to 76. East winds up to 15 mph.

Sunday: Sunny. Highs around 84. East winds up to 15 mph.

South Side

Today: Sunny. Highs around 90. North winds up to 10 mph shifting to the west in the afternoon.

Tonight: Mostly clear. Lows 69 to 76. Northwest winds up to 10 mph.

Sunday: Sunny. Highs around 90. Northwest winds up to 15 mph.

North Shore

Today: Breezy. Mostly sunny with isolated showers. Highs 80 to 87 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 73 near the shore to 50 to 55 near 5000 feet. Southeast winds up to 20 mph becoming 10 to 15 mph after midnight. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 80 to 87 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Central Maui

Today: Sunny and breezy. Highs 84 to 90. East winds up to 20 mph.

Tonight: Mostly clear. Lows around 71. East winds up to 15 mph.

Sunday: Sunny and breezy. Highs 83 to 90. East winds up to 20 mph.

Upcountry

Today: Mostly sunny with isolated showers. Highs around 67 at the visitor center to around 71 at the summit. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows 44 to 56. Southeast winds up to 10 mph. Chance of rain 20 percent.

Sunday: Sunny with isolated showers. Highs around 66 at the visitor center to around 71 at the summit. East winds up to 15 mph. Chance of rain 20 percent.

East Maui

Today: Breezy. Mostly sunny with isolated showers. Highs 80 to 87 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 73 near the shore to 50 to 55 near 5000 feet. Southeast winds up to 20 mph becoming 10 to 15 mph after midnight. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 80 to 87 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Lanai City

Today: Sunny. Highs 75 to 83. Light winds.

Tonight: Mostly clear. Lows around 67. Light winds.

Sunday: Sunny. Highs 75 to 82. Light winds becoming east up to 10 mph in the afternoon.

Kaunakakai

Today: Sunny. Highs 75 to 90. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows 61 to 74. East winds up to 15 mph.

Sunday: Sunny. Highs 75 to 90. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Detailed Forecast

Synopsis

The islands will remain under the influence of high pressure ridging to the north and east with a trough lingering far northwest of the state. This will result in light to locally breezy trade winds this weekend. There will be a slight drop off in wind speeds early next week in response to the trough slightly sagging south and weakening the downstream pressure gradient. A dry and stable weather pattern wins out in the near future with only occasional light windward mauka trade showers.

Discussion

Early morning satellite trends verify stable conditions with only scattered warm low topped clouds moving in on moderate east trade flow. Other than a few light showers coming onshore in Big Island's Puna region, the majority of the state remains dry. 12Z local soundings depict a continued 5-6k ft trade inversion height and much below normal near one inch precipitable waters. With little variance in the Central Pacific synoptic pattern for the foreseeable future, these summertime conditions will be the general theme through the remainder of August.
Mid to upper level ridging centered north and east of the islands will be the main control to persistent dry summer weather. The only caveat will be southern approach of a northern trough axis that may reach our northern offshore waters Monday and Tuesday. This will weaken the northeast-to-east ridge enough to cause a brief interruption in moderate to locally strong (oceanic) trade flow. Monday through Wednesday's winds will veer a bit more to the east-southeast and weaken a touch. Shortwave energy diving down around the base of the trough later next week will assist in keeping stronger trades at bay into the last few days of the month. Weaker trade flow within a drier scenario suggests that local breezes will become more dominant. Thus, early sun will likely lead to mid-late afternoon into early evening cloud build up and scattered showers over Big Island Kona and upslope leeward on Oahu. Moisture levels undergo little to no change so, other than localized afternoon breeze activity, the only other rain source will be from the typical brief topo-enhanced windward and mauka showers.

Aviation

Moderate to breezy easterly trade winds will persist through the forecast period. Clouds and showers will remain primarily focused to the windward mauka slopes, particularly during the nocturnal hours. Brief MVFR conditions will be possible within heavier showers, otherwise VFR will likely prevail.
No AIRMETs are currently in effect.

Marine

A high pressure ridge north of the Hawaiian Islands continues to produce fresh to locally strong trades through early next week. A Small Craft Advisory (SCA) remains in effect for the windier waters of Maui County and the Big Island. This SCA will likely continue into the first half of next week.
Small overlapping medium and long period south swells will continue today, this swell energy will fade into background levels by Sunday. Surf heights will continue to decline into Monday. Another small long period south swell will arrive by Tuesday, boosting south shore surf heights through Thursday.
Surf along north and west facing shores remains nearly flat. While small trade wind driven wave chop lingers out east.

Fire weather

The lack of rain and lower humidity will maintain elevated fire weather concerns this weekend. Other than the typical high terrain channeled winds, many locations will experience light to low end moderate trades or afternoon sea breezes/overnight land breezes. While many will experience afternoon humidities falling under 50 percent, lighter winds should hold Red Flag Warning (RFW) conditions at bay. These dry conditions have placed the majority of the state in a moderate to severe drought. Thus, regional scale winds will need to be the parameter that is most closely monitored in a potential RFW situation. Inversion heights will undergo little change so the main driver of wind will be supported in the large scale. Wind speeds are expected to fall off early next week in response to a northern trough weakening the gradient produced by eastern high pressure. As this trough pulls back further north at mid week, trades may slightly increase to more typical moderate speeds Wednesday.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov