Photo Credit: Tyler Rooke

West Side

Today: Sunny. Highs 76 to 82. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows 58 to 65. East winds around 10 mph in the evening becoming light.

Friday: Sunny. Highs 77 to 83. Northeast winds around 10 mph in the morning becoming light.

South Side

Today: Sunny. Highs around 82. North winds 10 to 15 mph.

Tonight: Clear. Lows around 59. North winds 10 to 15 mph shifting to the east after midnight.

Friday: Sunny. Highs around 83. Northeast winds around 10 mph in the morning becoming light.

North Shore

Today: Mostly sunny with isolated showers. Highs 74 to 79 near the shore to around 62 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows 56 to 62 near the shore to around 47 near 5000 feet. Southeast winds around 10 mph. Chance of rain 30 percent.

Friday: Mostly sunny with isolated showers. Highs 75 to 80 near the shore to around 61 near 5000 feet. East winds around 10 mph. Chance of rain 20 percent.

Central Maui

Today: Sunny. Highs 78 to 83. Northeast winds 10 to 15 mph.

Tonight: Mostly clear. Lows 57 to 62. Northeast winds 10 to 15 mph in the evening becoming light.

Friday: Sunny. Highs 79 to 84. Northeast winds around 10 mph in the morning becoming light.

Upcountry

Today: Sunny. Highs around 58 at the visitor center to around 54 at the summit. East winds around 10 mph.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 44 at the visitor center to around 40 at the summit. East winds around 10 mph. Chance of rain 20 percent.

Friday: Sunny. Isolated showers in the afternoon. Highs around 56 at the visitor center to around 52 at the summit. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

East Maui

Today: Mostly sunny with isolated showers. Highs 74 to 79 near the shore to around 62 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows 56 to 62 near the shore to around 47 near 5000 feet. Southeast winds around 10 mph. Chance of rain 30 percent.

Friday: Mostly sunny with isolated showers. Highs 75 to 80 near the shore to around 61 near 5000 feet. East winds around 10 mph. Chance of rain 20 percent.

Lanai City

Today: Sunny. Isolated showers in the afternoon. Highs 72 to 79. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 62. Northeast winds around 10 mph.

Friday: Sunny. Isolated showers in the afternoon. Highs 73 to 80. North winds around 10 mph in the morning becoming light. Chance of rain 20 percent.

Kaunakakai

Today: Sunny. Highs 71 to 81. East winds 10 to 15 mph.

Tonight: Mostly clear. Isolated showers in the evening. Lows 51 to 63. East winds around 10 mph. Chance of rain 20 percent.

Friday: Sunny. Isolated showers in the afternoon. Highs 71 to 81. Northeast winds around 10 mph in the morning becoming light. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Big Island will continue to experience moderate trade winds through Friday, while lighter trade winds shift southeasterly at times across the rest of the island chain. Minimal showers will continue over windward slopes, and daytime sea breezes will produce clouds and isolated showers over some leeward areas each afternoon. Trade winds and windward rainfall will increase during the weekend.

Discussion

As expected, little change to the forecast with the morning package. An overnight ASCAT pass missed most of the islands, but did clip Kauai and continued to show the light winds that were forecast in that area.
The ridge remains just northwest of Kauai this morning, with the front to the northwest of the ridge falling apart. This is expected to allow the ridge to lift north a bit more today, helping trades to filter into some additional areas of the smaller islands today. But overall winds will likely remain light enough to support afternoon sea breezes. The dry and stable air mass over the islands will continue to limit rainfall totals. Another front approaching Friday will once again nudge a ridge towards the islands, so expect weaker winds once again particularly over the Kauai/Oahu area.
Heading into the weekend, the latest front is expected to dissipate north of islands, with high pressure building to the north. This will allow trades to gradually strengthen on Saturday and may become locally breezy on Sunday. An area of moisture upstream of the islands will ride in on the trade winds, and is expected to reach the Big Island Friday night. The moisture is then expected to spread to the remaining island over the weekend, so expect an uptick in shower activity.
The ridge aloft of the islands that is helping to hold the dry and stable air mass in place is expected to erode at the end of the week as an upper level trough passes over/east of the islands. This could help to enhance some of the rainfall totals. Moderate trade winds and a more typical pattern of windward rainfall is likely early next week.

Aviation

Light east trades and afternoon sea breezes are expected across the islands today as a high pressure ridge remains in place, while a weakening cold front slowly approaches the state from the west. Any sea breeze which develops this afternoon, will diminish this evening during the diurnal transition toward land breeze circulations. Moisture will remain limited again today, focusing isolated showers and clouds to windward slopes and inland along afternoon sea breezes. VFR conditions will prevail across the state with brief periods of MVFR cigs possible in developing showers.
No AIRMETs are currently in effect. Though a period of possibly brief moderate upper lvl turb could still be noted within the inter-island air routes and flight areas within 40nm of the main Hawaiian Islands this morning as upper jet dynamics exit east.

Marine

A surface ridge axis extending from a high centered off the northern California coast has settled in just north of the islands. The resultant weak pressure gradient produced by the ridge will continue to generally support light to gentle east breezes. Late week east trade winds will remain light to occasionally moderate as a surface trough moves in from the east while the tail end of a front skims the far northern offshore waters today. The regional pressure gradient produced by the high northeast of the region will become better established this weekend. The result will be a return of moderate to locally strong east trades from Saturday night through early next week.
Surf along many north and west facing shores will hold through the morning hours as the next 310 to 320 degree moderate size, medium period swell enters the far northwestern offshore waters today. As of 0300 AM HST, the longer period forerunners are not yet showing up at the far northwest offshore buoys, but there is moderate to high confidence that a 6 to 7 foot swell will fill in across the western and central islands later this afternoon through Friday morning. This swell will push Kauai's north and west facing shore surf up to Surf Advisory (SCA) thresholds Friday morning with O'ahu's north and west shores nearing SCA heights by Friday afternoon. A slightly larger northwest swell will arrive a day later on Saturday. Smaller island north and west facing shore surf will likely exceed SCA levels this weekend as this secondary, reinforcing swell passes through Saturday. East facing shore surf will trend up a little into the weekend as a small easterly swell originating from an upstream fresh to strong trade fetch moves in…along with some northwest wrap. Surf along south facing shores will receive a couple of small late week bumps from the arrival of very small, medium period southerly swells. In the extended, a moderate size, medium period swell (very similar to the two coming through the next couple of days) will reach the western- most islands next Wednesday and push north and west facing shore surf back to near SCA levels.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov