Surf along the north shores should be a combination of small mid-period northwest swell mixed with moderate windswell out of the northeast, offering surf in the head-high range at many spots and possibly higher at the best locations. Nothing more than tiny southwest swell is likely for any of our south facing shores and much of this energy is blocked by Kaho`olawe. There is nothing of note expected out of the south hemisphere throughout the forecast period. A new north-northwest swell is expected to arrive overnight Saturday into Sunday to provide surf near double-overhead levels at the best exposed breaks, possibly increasing to near advisory levels Monday. An approaching frontal system will cause a decrease in the tradewinds over the next several days but this pattern will changed early next week as stronger northeast winds build behind this front. This swell was generated by a gyre near the dateline which developed a large fetch aimed in our direction. This should be a long-lived event stretching into the middle of the week. There is a potential for another minor north or north-northeast swell arriving later in the week if a low develops north-northeast of the state as currently forecast, but this can certainly change. Otherwise, no significant swells are expected through the rest of the forecast period.
Today’s Surf Summary
North and northwest facing shores should be around 4-6 foot today, rising to 6-10+ foot Sunday and Monday. Upper West shores may see some small surf around 2-5 foot at the better locations. Windswell along the east and northeast facing shores should be around 3-5 foot but select areas may pull in larger sets. South facing shores won’t see much at only 0-3 foot.
Wind and Tide Information
High tide at Kahului was 2.7 foot at 2:42 AM late last night, dropping to a low of 0.8 foot at 8:58 AM this morning, then rising to a high of 1.6 foot at 1:37 PM early this afternoon, before once again dropping to a low of -0.4 foot at 8:03 PM early this evening
The sunrise was at 06:40 am this morning and will set at 05:44 pm this evening. The Moon is currently 0 days old, and is in a New Moon phase. The next Waxing Crescent will occur at 10:07 AM on Saturday, November 29th.
The easterly tradewinds will continue at moderate levels of 10-20 mph across much of the island today although some areas will be lighter. A decreasing trend is expected over the next few days as a frontal system approaches the islands, dropping wind speeds to light levels out of the south.
Sunset: 5:43 PM
Weather Outlook for Saturday
Moderate trade winds will diminish today. Showers will be limited mainly to windward slopes, especially over the Big Island. A front will bring modest rain and stronger, northerly winds to most of the state from Sunday night into Tuesday. The winds then will weaken and become northeasterly again as the cool and dry air mass moistens gradually into Friday.
Observations around the main Hawaiian islands reported winds gradually becoming more southeasterly, but still remaining strong enough to require extending the small craft advisory in places around the Big Island. Aloft, the ridge languishing across the state from west to east thinned out between shallow troughing to south, and a deepening long-wave trough to the north. A jet stream associated with the trough to the south brought cirrus layers from the ITCZ as far north as Maui county, and cloud cover was increased accordingly. However, the mid-level ridge remained strong enough to limit the inversion to near its usual height.
Lower cloud cover consisted mainly of generally stable clouds. Various measures of precipitable water depicted a relatively dry air mass upwind of most of the state, excepting only south slopes of the Big Island. Rain gauges reported little accumulation through the night. On the other hand, radar detected enough shower activity over the water so that the current pop grids for later today nonetheless appeared plausible given the predicted breakdown of the ridge aloft.
Guidance still largely agreed that the deepening long-wave trough aloft to the north will start to displace the mid-level ridge toward the east, finally supporting the approach at the surface of the front currently crossing 30Â°N near 170Â°W. As the surface ridge retreats to the southeast ahead of the front, the trade winds will diminish and become increasingly southeasterly.
The front itself should reach Kauai by Sunday night, but solution consensus predicted the supporting mid-level trough to focus mainly to the east of the state. Thus, most development along the front should remain northeast of the islands, leaving only a fairly shallow boundary to move down the state from Sunday night into Tuesday. Some rain will accompany the front, mainly over the smaller islands. The Big Island more likely will experience a less organized increase in showers from the frontal remnants moving ashore along northeast slopes on Tuesday and Tuesday night. Moderate to strong northerly winds in the cooler and drier air mass behind the front may be more significant than the front itself.
From Wednesday into the latter half of the week, the subtropical ridge will reestablish itself north of the state gradually, returning local winds to a more familiar northeasterly direction, though wind speeds will drop off significantly until the ridge shifts far enough north. The cool and dry air mass will modify in place, allowing windward showers to increase again with time.
Central Valley (Kahului, Spreckelsville):
Mostly clear. Lows 64 to 70. East winds up to 10 mph until early morning becoming light.
Leeward West (Lahaina, Ka`anapali):
Mostly clear. Isolated showers in the evening. Lows 64 to 72. East winds up to 10 mph. Chance of rain 20 percent.
Windward West (Wailuku, Waiehu):
Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 58 to 71. East winds up to 10 mph. Chance of rain 50 percent.
Windard Haleakala (Hana, Haiku, Makawao):
Mostly cloudy with scattered showers. Lows around 70 at the shore to around 52 at 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.
Leeward Haleakala (Kihei, Wailea, Makena):
Mostly clear. Lows around 68 at the shore to around 52 at 5000 feet. Light winds.
Mostly clear with isolated showers. Lows around 49 at 7000 feet to around 46 at the summit. Southeast winds around 10 mph. Chance of rain 20 percent.
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