6-10+ foot
2-4+ foot
0-3 foot
2-4 foot

The light to moderate trade winds will be giving way to a light and variable wind situation over the western part of the island chain by tonight, while a light to moderate easterly wind flow prevails elsewhere. This comes about as a trough forms in the vicinity of Kauai later today and stays put there through Thursday. A front is then forecast to weaken as it enter the northwest offshore waters Thursday night and Friday. To make the situation more complicated, an upper level disturbance has brought in some instability to the area, resulting in the potential for a thunderstorm or two mainly over the western waters initially, then all waters Thursday through Friday.

As the front weakens, high pressure strengthens over the area resulting in strong trades over the weekend.

We are expected a reinforcing northwest swell that will bring the surf heights up along the north and west facing shores on Wednesday to near advisory levels. Deep ocean buoy 51001, located some 180 nm northwest of Kauai, has been indicating a 9 foot sig wave height for the evening with a 14 second period out of the NW. This is about or slightly smaller than Wave Watch guidance. We will continue to monitor the situation closely through this morning, but it looks like a non-advisory swell at this time.

A significantly larger northwest swell is expected to reach north and west facing shores of Kauai as early as late Thursday afternoon (as per GFS), and spread down the island chain Thursday night through Friday. This swell is expected to max out around 9 to 10 feet on Friday with a period of around 18 seconds. This translate to surf heights at or near warning level of 25 feet for the north facing shores. The west facing shores will also be impacted with warning level surf. This swell was generated by an intense storm with a history of hurricane forced winds. This system has since weakened, and is currently 1700 nm northwest of Kauai.

This swell gradually fades over the weekend. Then perhaps, a series of reinforcing west-northwest swell reaches the islands north and west facing shores beginning on Monday, peaking on Tuesday night. Wave Watch guidance is giving a maximum swell height of 7 feet and 15 seconds, equating to near advisory level surf for the north and west facing shores.

Strong, persistent trades east of the islands has generated an easterly swell that will keep the surf up along east facing shores even as the trades become light and variable over some parts of the island chain in the next couple of days. Moderate to strong and gusty trades are on tap on returning over the weekend, and this will bump the surf along east facing shores to near advisory level.

There are no marine warnings at the moment. However, a Small Craft Advisory is likely on Thursday through Friday for most near- shore waters as the large northwest swell arrives. Some scaling back of the near-shore zones may ensue as the the large swell fades, but the return of moderate to strong trades may just keep them in place over the upcoming weekend.

Hawaii Wave Height Model

Tide Predictions

High tide at Kahului was 2.66 foot at 2:00 PM early this afternoon, dropping to a low of 0.72 foot at 2:00 PM early this afternoon, then rising to a high of 1.14 foot at 2:00 PM early this afternoon, before once again dropping to a low of 0.08 foot at 2:00 PM early this afternoon.

The sunrise was at 06:59 am this morning and will set at 05:54 pm this evening. The Moon is currently 19 days old, and is in a Waning Gibbous phase. The next Last Quarter will occur at 9:36 AM on Saturday, December 29th.

Hawaii Wind Report

Maui Weather

°/°
Wind: n/a at 0 mph
Sunrise:
Sunset:
current observations as of 5pm January 15th, 2019

Weather Outlook for Wednesday, 26th December 2018

Summary

A wet pattern is expected through the second half of the week and into the upcoming weekend as a cold front approaches and moves into the area. The front is forecast to move over the islands and stall Thursday night into the weekend, then gradually diminish. Locally heavy rainfall along with a few thunderstorms will become a possibility through this time, especially late Thursday through Friday for the northwest islands. Conditions should gradually begin to improve late in the weekend, with a return of drier trade wind conditions early next week.

Detailed Discussion

Although the better instability associated with an upper trough remains north and away from the state this morning, plenty of low-level moisture in place along with light to moderate southeast low-level flow will support localized heavy rainfall into Thursday. Satellite-derived precipitable water (PW) imagery and recent upper air soundings reflected this wet pattern with above average values for this time of year (1.4-1.6″). Winds will steadily trend down as a cold front and upper trough approach the region today, which will be enough for land and sea breeze conditions to become established for some areas (especially for Kauai/Oahu). This will translate to a more diurnal pattern with the better rainfall potential setting up through the afternoon periods through Thursday.

Guidance remains in decent agreement Thursday through Saturday and shows an amplifying upper pattern setting up over the region featuring a sharp upper trough digging southeastward over the state beginning Thursday night. The upper trough may be sharp enough for an upper low to pinch off near or just south of the islands Friday into the weekend. This combined with its attendant cold front moving over the islands and stalling through this time will keep the chances for heavy rainfall and flooding as the primary forecast concern. Additionally, upper height falls destabilizing the airmass combined with the surface boundary and deep moisture will support thunderstorms, especially over the northwest islands.

Improving conditions will be likely by the end of the weekend and into early next week as the previously discussed front diminishes and high pressure builds to the north. Drier conditions along with a more typical trade wind pattern will be likely.

Central Valley (Kahului, Spreckelsville):

Partly cloudy with isolated showers. Lows 62 to 67. Light winds. Chance of rain 20 percent.

Leeward West (Lahaina, Ka`anapali):

Partly cloudy with isolated showers. Lows 63 to 68. Light winds. Chance of rain 20 percent.

Windward West (Wailuku, Waiehu):

Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 57 to 68. Light winds. Chance of rain 30 percent.

Windard Haleakala (Hana, Haiku, Makawao):

Mostly cloudy with scattered showers. Lows around 67 at the shore to around 51 at 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Leeward Haleakala (Kihei, Wailea, Makena):

Partly cloudy with isolated showers. Lows around 66 at the shore to around 54 upcountry. East winds up to 10 mph. Chance of rain 20 percent.

Haleakala Summit

Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 47 at the visitor center to around 42 at the summit. East winds 10 to 15 mph. Chance of rain 40 percent.