Photo Credit: Randy Alona Gallegos

West Side

Today: Sunny, with a high near 87. Calm wind becoming south 5 to 8 mph in the afternoon.

Tonight: Mostly clear, with a low around 64. South wind 5 to 8 mph becoming north northeast after midnight.

Sunday: Sunny, with a high near 88. South southeast wind 5 to 9 mph becoming light east in the afternoon.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 87. Calm wind becoming south 5 to 8 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 63. South wind 5 to 7 mph becoming calm after midnight. Chance of precipitation is 20%.

Sunday: Isolated showers after noon. Mostly sunny, with a high near 88. Calm wind becoming southwest 5 to 8 mph in the afternoon. Chance of precipitation is 20%.

North Shore

Today: Isolated showers before noon. Sunny, with a high near 86. East northeast wind 6 to 13 mph. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 64. East wind 6 to 8 mph becoming south after midnight.

Sunday: Mostly sunny, with a high near 87. Calm wind becoming east 5 to 7 mph in the afternoon.

Central Maui

Today: Isolated showers before 1pm. Mostly sunny, with a high near 87. Northwest wind 5 to 13 mph becoming north northeast in the afternoon. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 62. West southwest wind 5 to 7 mph becoming calm.

Sunday: Mostly sunny, with a high near 88. Light and variable wind becoming south around 5 mph in the morning.

Upcountry

Today: Mostly sunny, with a high near 72. Calm wind becoming west around 6 mph in the afternoon.

Tonight: Partly cloudy, with a low around 52. West wind around 5 mph becoming calm in the evening.

Sunday: Mostly sunny, with a high near 73. Calm wind becoming west 5 to 9 mph.

East Maui

Today: Scattered showers, mainly before noon. Mostly sunny, with a high near 81. South southeast wind 5 to 11 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 61. Southeast wind 9 to 11 mph becoming west in the evening. Chance of precipitation is 20%.

Sunday: Isolated showers. Mostly sunny, with a high near 82. East southeast wind 6 to 11 mph. Chance of precipitation is 20%.

Lanai City

Today: Scattered showers after noon. Mostly sunny, with a high near 76. Calm wind becoming south 5 to 8 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before midnight. Partly cloudy, with a low around 62. South wind 6 to 13 mph becoming east in the evening. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers, mainly after noon. Partly sunny, with a high near 77. Southwest wind 9 to 14 mph becoming light and variable in the afternoon. Winds could gust as high as 18 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kaunakakai

Today: Sunny, with a high near 87. Calm wind becoming south southeast 5 to 9 mph in the afternoon.

Tonight: Mostly clear, with a low around 66. South southeast wind 6 to 9 mph becoming east in the evening.

Sunday: Mostly sunny, with a high near 87. Southwest wind 5 to 8 mph becoming calm in the afternoon.

Detailed Forecast

Synopsis

A passing cold frontal system far north of the Hawaiian Islands will weaken the high pressure ridge north of the state, producing light and variable winds through the Memorial Day weekend. Continued warm temperatures and humid trends are expected each day. Stable atmospheric conditions aloft will limit cloud and shower activity. Daytime onshore sea breezes will produce some interior clouds with just a few showers favoring island mountain and interior sections from afternoon through evening. Overnight land breezes will clear out most of the island cloud cover. The high pressure ridge north of the islands will build from Tuesday onward with returning moderate to locally breezy trade wind weather expected to last into next weekend.

Discussion

Satellite imagery this morning shows a cold frontal system passing north of the Hawaiian Islands, a narrow upper level trough and a weak subtropical jet persist south of the region. Radar imagery shows clouds and showers lingering near Kona on the west side of the Big Island.
The subtropical ridge north of the islands will break down as a low pressure frontal system moves slowly through the north Central Pacific over the next three days. Trade winds will diminish overnight producing a light and variable wind pattern over the region. In the absence of large scale winds, island heating and cooling relative to the ocean temperatures will produce local scale land and sea breezes through the Memorial Day weekend. An upper level ridge will produce large scale subsidence stabilizing the atmosphere over the region. Subsidence inversion heights will range from the 5000 to 8000 foot level limiting cloud and shower development during this light wind pattern. Humidity level will trend higher due to the lack of trade winds. Weather conditions this holiday weekend will be excellent for outdoor activities!
Weather conditions will change back to moderate to locally breezy trade winds from Tuesday onward as the subtropical ridge builds back in north of the Hawaiian Islands. Humidity levels will drop as drier air rides into the region. Clouds and brief passing showers will favor windward and mountain areas of each island with higher trends in the overnight to early morning hours.

Aviation

A weak surface ridge a few hundred miles north of the islands will shift southward as it further weakens. Weak background flow will veer from east northeast to east southeast over the next twenty four hours. This will result in an increase of both afternoon sea breezes and late night land breezes over the weekend.
Afternoon sea breezes will focus shallow cumulus buildups over island interiors. The air mass will remain mostly dry and mostly stable, so associated shower activity will remain minimal. Sea breezes will give way to land breezes after sunset and promote nighttime clearing along leeward slopes and coasts.

Marine

A front will approach from the northwest over the Holiday weekend, bringing light and variable winds to the western islands, while light to moderate southeasterly winds prevail over the eastern end of the state. Trade winds will return from east to west across the island chain Monday night and Tuesday, and strengthen to moderate and locally strong levels by the middle of next week.
A series of small south and south-southwest swells will keep near to slightly below normal surf in place along south facing shores through Wednesday. South shore surf could trend up slightly late next week as a new south-southwest swell moves through the island chain.
Surf along north and west facing shores will remain small today, then trend up Sunday through Tuesday as a new northwest swell moves through. This swell will then trend down Wednesday through late next week.
Surf along east facing shores will remain small through Tuesday, then trend up Wednesday through late next week as the trades strengthen over and upstream of the islands.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov