The National Weather Service has issued a High Surf Advisory for Maui’s north shore, effective through 10am Sunday morning. Leftover swell is expecetd to gradually subside through Saturday, but a new slightly larger and longer-period north northwest swell will spread down across the islands over the weekend. Surf produced by this swell is expected to build along Maui’s north facing shores through Saturday, peaking near high surf advisory levels, so a high surf advisory has been issued starting late Saturday morning for north facing shores of Maui. This swell is expected to gradually subside on Sunday. A small pulse from the northwest is possible on Monday, with a potentially larger north northwest swell arriving Wednesday. A small to moderate long-period south southwest swell is forecast to arrive early next week, and then persist for much of the week. Although the surf won’t go flat next week, we shouldn’t expect much size in any of these upcoming swells. The winter season is winding down and we are already starting to see some pre-season energy out of the southern hemisphere.
Today’s Surf Summary
North and northwest facing shores should rise into the 6-10+ foot range Saturday, then decreasing to above head-high levels Sunday. Upper West shores should see surf in the 4-6+ foot range at the better exposed breaks, possibly higher at the best locations. South facing shores will stay flat Saturday around 0-2 foot but should build over the next few days to head-high levels as a new south-southwest swell fills in. Windswell along the east and northeast facing shores is also on the rise and should build to 2-5 foot through Sunday.
Wind and Tide Information
High tide at Kahului was 2.2 foot at 3:01 AM late last night, dropping to a low of -0.3 foot at 9:16 AM this morning, then rising to a high of 2.2 foot at 3:38 PM early this afternoon, before once again dropping to a low of 0.1 foot at 9:41 PM late this evening
The sunrise was at 06:26 am this morning and will set at 06:38 pm this evening. The Moon is currently 1 days old, and is in a Waxing Crescent phase. The next First Quarter will occur at 7:43 AM on Friday, March 27th.
Moderately breezy tradewinds of 15-20 mph will blow out of the east to northeast today, increasing slightly into Sunday. The winds are expected to decrease Tuesday and Wednesday while swinging to a more southeasterly direction.
Sunset: 6:39 PM
Weather Outlook for Saturday
Trade winds will gradually strengthen through Saturday, and remain locally breezy on Sunday. The trades will deliver low clouds and showers to windward and mauka sections of the aloha state through Saturday. The gusty trade winds will also carry a few showers over to leeward sections of some of the smaller islands. Winds will become light with drier conditions expected early next week, followed by strengthening trade winds and increasing trade showers returning again starting next Wednesday.
High pressure about 500 miles northwest of Lihue, is moving toward the east northeast at about 20 mph, a surface ridge extends east of this high, through a point more than 500 miles north of Hilo. The tight pressure gradient south of these features to the north of the aloha state is maintaining breezy northeast to east winds across the island chain early this evening.
Elsewhere, the tail end of the decaying front is evident more than 500 miles east northeast of Hilo. Satellite imagery shows low clouds and showers associated with this feature being transported by the low-level trade wind flow toward the island chain. In addition, an area of slightly enhanced low-level moisture is evident just upstream of Maui county and the Big Island. Aloft, the mid-tropospheric flow directly above the state appears to be nearly zonal. Inversion heights from the early afternoon soundings at Lihue and Hilo showed this feature was between 8 and 10 thousand feet. As a result, even though the atmosphere remains relatively stable across the islands, the low clouds and showers riding in on the trades are being enhanced locally be orographic lift as they reach the islands. So most windward and mauka areas remain wet early this evening. Also, the breezy low-level trade wind flow is carrying a few of these showers over to leeward sections of some of the smaller islands.
The forecast models indicate the pressure gradient will remain tight across the area through early Sunday, as surface high pressure remains anchored north of the area. At the same time, the moisture from upstream sources will continue to ride in on the trades, which will continue to produce wet weather over most windward and mauka sections of the state through Saturday night. By Sunday, the moisture associated with the dissipated front is expected to lift north. This will likely lead to fewer trade showers. Trade winds will also begin to gradually weaken late Sunday, as the ridge trailing west from the high begins to move closer to the islands in response to a new front approaching from the northwest.
As the ridge continues to shift closer to the islands early next week, the surface winds will initially shift to an east southeast direction near Kauai, with moderate east winds expected to continue in the vicinity of the Big Island. As the background flow continues to weaken in response to th ridge moving closer the area, a diurnal pattern of local nighttime land breezes and afternoon sea breeze circulations will likely develop over each of the individual islands. The afternoon sea breezes will result in afternoon cloud and isolated showers mainly over interior and leeward sections of the islands, with clearing skies over most areas at night. In addition, volcanic haze from sources on the Big Island may spread to the smaller islands from Monday night through Tuesday. However, confidence in this forecast is low, since the latest model guidance indicates that low-level wind trajectories may not be conducive for the volcanic haze to be transported to the smaller islands.
From Tuesday night through Thursday, the numerical forecast output indicates a new surface high building northwest of the main Hawaiian island chain will push the aforementioned weakening front closer to Kauai. If so, expect increasing northeast winds on Wednesday, followed by the low-level flow veering to the east by Thursday. Similar the current regime, moisture associated with the front, which is expected to gradually weaken as it arrives in the area, will allow the development of enhanced trade wind showers, especially over windward and mauka sections of Kauai and Oahu.
The long-range forecast models also show a mid-level ridge just south of the islands will keep relatively stable atmospheric conditions across the area around mid-week. This ridging aloft is expected to strengthen as it shifts northward directly above the island chain during the second half of next week. As a result, these increasingly stable conditions will likely not allow deep convection or heavy rain to develop. However, abundant showers associated with the front next week may once again soak north facing slopes and the higher terrain on Kauai once again.
Central Valley (Kahului, Spreckelsville):
Breezy. Mostly clear with isolated showers. Lows 65 to 70. Northeast winds 15 to 20 mph with gusts to 35 mph. Chance of rain 20 percent.
Leeward West (Lahaina, Ka`anapali):
Breezy. Partly cloudy with isolated showers. Lows 66 to 72. Northeast winds 15 to 20 mph. Chance of rain 20 percent.
Windward West (Wailuku, Waiehu):
HIGH SURF ADVISORY IN EFFECT FROM 10 AM THIS MORNING TO 10 AM HST SUNDAY. Breezy. Partly sunny with scattered showers. Highs 66 to 79. Northeast winds 15 to 20 mph. Chance of rain 50 percent.
Windard Haleakala (Hana, Haiku, Makawao):
HIGH SURF ADVISORY IN EFFECT FROM 10 AM THIS MORNING TO 10 AM HST SUNDAY. Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 78 at the shore to around 65 at 5000 feet. East winds 10 to 15 mph with gusts to 30 mph. Chance of rain 70 percent.
Leeward Haleakala (Kihei, Wailea, Makena):
Mostly clear. Lows around 68 at the shore to 52 to 57 upcountry. East winds 10 to 15 mph.
Breezy. Partly cloudy with isolated showers. Lows around 47 at the visitor center to around 43 at the summit. East winds 15 to 25 mph. Chance of rain 20 percent.
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