Photo Credit: Travis Guthrie

West Side

Today: Mostly sunny, with a high near 77. Northeast wind 5 to 7 mph becoming calm.

Tonight: Mostly clear, with a low around 60. North northwest wind around 6 mph becoming light and variable after midnight.

Saturday: Mostly sunny, with a high near 79. Light and variable wind.

South Side

Today: Isolated showers after noon. Partly sunny, with a high near 77. Northeast wind 5 to 9 mph becoming west southwest in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers after midnight. Mostly clear, with a low around 58. North northeast wind 5 to 10 mph becoming light and variable after midnight. Chance of precipitation is 20%.

Saturday: Mostly sunny, with a high near 79. Light and variable wind becoming west around 6 mph.

North Shore

Today: Isolated showers. Mostly sunny, with a high near 75. Calm wind becoming north northwest 5 to 7 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 59. North northwest wind 5 to 7 mph becoming calm in the evening.

Saturday: Sunny, with a high near 77. Calm wind becoming north northwest around 5 mph.

Central Maui

Today: Isolated showers before 1pm. Mostly sunny, with a high near 77. Calm wind becoming north northwest 5 to 7 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 57. North wind 5 to 7 mph becoming calm after midnight.

Saturday: Sunny, with a high near 79. Light and variable wind.

Upcountry

Today: Isolated showers after 1pm. Partly sunny, with a high near 62. Calm wind becoming south southwest 5 to 7 mph in the morning. Chance of precipitation is 20%.

Tonight: Isolated showers before 7pm, then isolated showers after 1am. Partly cloudy, with a low around 47. Calm wind becoming south 5 to 7 mph after midnight. Chance of precipitation is 20%.

Saturday: Isolated showers before 7am. Mostly sunny, with a high near 64. South wind 7 to 9 mph becoming west in the afternoon. Chance of precipitation is 20%.

East Maui

Today: Scattered showers, mainly before noon. Partly sunny, with a high near 75. Northwest wind 6 to 9 mph becoming east northeast in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 55. West northwest wind 6 to 9 mph. Chance of precipitation is 20%.

Saturday: Mostly sunny, with a high near 77. West northwest wind around 6 mph becoming calm in the morning.

Lanai City

Today: Scattered showers after noon. Mostly cloudy, with a high near 71. Light and variable wind becoming north northwest 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: Isolated showers after midnight. Partly cloudy, with a low around 55. North northwest wind 5 to 8 mph becoming calm after midnight. Chance of precipitation is 20%.

Saturday: Isolated showers after noon. Increasing clouds, with a high near 72. Calm wind becoming north northwest around 6 mph in the afternoon. Chance of precipitation is 20%.

Kaunakakai

Today: Isolated showers before noon. Mostly sunny, with a high near 75. Northeast wind 5 to 11 mph becoming west southwest in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers after midnight. Partly cloudy, with a low around 59. North wind 6 to 11 mph becoming light after midnight. Chance of precipitation is 20%.

Saturday: Mostly sunny, with a high near 77. Calm wind becoming west southwest 5 to 7 mph.

Detailed Forecast

Synopsis

The cool and mostly dry conditions are expected to linger into the weekend, with clouds and showers favoring north and west slopes of the smaller islands today. The northwest winds will become light enough for a land and sea breeze pattern to setup by this afternoon, which will support mostly clear nights and mornings over the weekend. Although some interior cloud development will be possible through the afternoon hours, the dry air in place will limit rainfall chances. A front may bring another round of widespread rainfall early next week. Drier air will follow the front from west to east around midweek.

Discussion

Despite the drier and cooler airmass that has moved in over the state, clouds and brief/light showers continue to impact most north and west facing slopes of the smaller islands this morning with the northwest winds in place. Expect this trend to hold today, especially through the morning hours as a band of clouds move through from west to east. Deeper moisture lingering over the Big Island combined with plenty of instability associated with the upper trough over the region will continue to support localized heavy showers and even a thunderstorm or two today, mainly through the afternoon and early evening periods.
Expect the dry and cool conditions to linger over the weekend, with light northwest low-level winds continuing. Temperatures will hold just below normal with dewpoints dipping into the 50s each afternoon. The low-level flow will ease enough to give way to a land and sea breeze pattern, which will translate to mostly clear nights and mornings and some afternoon clouds across interior areas. Rainfall chances will remain limited with the dry conditions in place.
Another cold front will affect the state early next week. As this system approaches on Monday, winds will shift out of the south and increase to moderate levels. Despite some notable timing differences between different sources of guidance, another round of widespread rainfall appears possible Monday through Tuesday as this feature moves through. Localized flooding and a few thunderstorms could accompany the front. More details will follow over the weekend as confidence increases. Drier air will fill in from west to east through the midweek period.

Aviation

Weakening post-frontal northwest flow will continue to push patchy showery low clouds across north through west areas of the smaller islands today. VFR conditions will prevail at the terminals.

Marine

A weakening cold front east of the islands will slow its eastward progression and eventually wash out over the far eastern offshore waters this weekend. Scattered thunderstorms surrounding the Big Island, some locally strong, will occur in the vicinity of this front through the morning hours. The slow eastern exit of the upper low north of the state will keep the associated surface low meandering north of the chain through Sunday morning. This will have near term gentle to moderate northwest to north winds backing more westerly going into the weekend. Weekend west breezes will be gentle to moderate north of the islands, or closer to the surface low, with light westerlies over the islands and points south. Weak ridging over the state will produce very light and variable breezes across all local waters Sunday into Monday. Monday’s winds will become more southwest as the state falls downstream of the next cold front to the northwest. This front is timed to pass over the local waters Monday night into Tuesday morning.
As current elevated northwest swells slowly diminish this weekend, the sea state will calm. Small Craft Advisory (SCA) level seas will continue their gradual decline through Saturday and will likely fall below SCA criteria around midnight Sunday. The current SCA has been extended out into early Saturday morning for all waters affected by these passing northwest swells.
The ongoing large northwest swell that is producing warning level surf along the northern and western-facing shores of Niihau, Kauai and Oahu…along with advisory surf on north-facing Maui and the Big Island Kona Coast…will hold through the day and then subside beginning tonight. A mix of both these longer period northwest swells and medium period north-northwest swells generated from a fetch region along the backside of low north of the area may produce advisory level surf along exposed north and west-facing shores through Saturday night. New northwest swells arriving Monday night into Tuesday have a reasonable chance of building surf back to advisory levels along these north and west-facing shorelines.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST this evening for Niihau, Kauai Windward, Kauai Leeward, Waianae Coast, Oahu North Shore, Oahu Koolau.
High Surf Advisory until 6 PM HST this evening for Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala, Kona, Kohala.
Small Craft Advisory until 6 AM HST Saturday 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, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov