Average swells this week, good strong N/NW groundswell Sunday
Hawaii North Shore forecast by Craig Brokensha (issued Tuesday 8th March)
Best Days: Thursday, Friday, Sunday, Monday, Tuesday morning
This week and next (Mar 9 - 18)
After a large kick in NW groundswell Sunday, wave heights have steadily dropped away, easing further today from the 8ft+ range early.
The easing trend should be arrested tomorrow with the arrival of a small mid-period NW swell, keeping 4-6ft sets hitting swell magnets across the North Shore. Winds will take a bad turn though with a fresh SW tending W/SW breeze and then strong N'ly into the afternoon as a cold front pushes down into the islands.
As talked about on the weekend, some new mid-period N/NW swell will be generated by this front, but with no decent size or power as a result of the weak core fetch. Junky 6ft+ surf should be seen through the morning Wednesday, easing back through the afternoon as poor and gusty N/NE tending NE winds blow across the coast.
A better W/NW groundswell is due into Thursday morning, produced between us and Japan by a fetch of W/NW gales through our western swell window.
The westerly nature will limit wave heights slightly, but we should see inconsistent sets in the 6ft+ range again Thursday morning, easing off Friday and further into Saturday.
Conditions should improve with gusty trades from Thursday morning, easing back a touch into the weekend.
The next significant swell will be a long-period N/NW groundswell for the weekend.
Later this week, a vigorous low pressure system is forecast to form off the Aleutian Islands, further east than we've seen past systems the last couple of months, projecting a fetch of severe-gale to storm-force W/NW winds towards the US West Coast.
This will be perpendicular to our north-western swell window, but the strength of the storm and winds should still see some large N/NW groundswell spreading radially down into us, arriving later Saturday in the 20s range but with no real size, ahead of a peak Sunday midday to 10-12ft across the North Shore, bigger on Maui.
Good but gusty E'ly trades are due for this swell, weakening and tending more variable as it fades Monday and Tuesday.
Longer term there's nothing too significant on the cards for the rest of the week, but more on this Thursday.