Poor winds to spoil swells
Hawaii North Shore forecast by Craig Brokensha (issued Mon 22nd December)
Best Days: No good days, Monday for keen surfers
This week (Dec 23 - 26)
A large increase in NW groundswell yesterday afternoon has dropped back a touch into today but has held in the large range although with poor and fresh to strong N/NE winds.
Over the coming days we'll see the swell back away steadily out of the NW, from the 10ft range tomorrow, but winds will continue to be problem tomorrow, strengthening further from the N/NE. This will be related to a trough sitting to our east squeezing against a strengthening high moving in from the west.
A junky but solid N/NE windswell will build from the strong fetch of NE winds off our coast, reaching 6ft+ tomorrow afternoon and then easing back through Wednesday with the NW groundswell from a mixed 8ft or so. Winds will start to ease into Wednesday but swing to a poor W/NW and re-strengthen from the N/NW into Friday and Saturday as the trough forms a small surface low.
This weekend onwards (Dec 27 onwards)
Our next pulse of swell is due out of the NW through Saturday/Sunday ahead of a secondary increase Monday.
The source of Saturday's increase will be a strong and broad frontal system currently moving off Japan with a fetch of W/NW gales being aimed towards us while the storm pushes towards the Aleutians.
The swell should build to the inconsistent 6-8ft range across the North Shore during Saturday evening and then ease from a similar size Sunday morning. A secondary longer-period and stronger NW groundswell for Monday morning will be generated by a very strong but small and tight low firing up off the Aleutians Friday.
A quick burst of severe-gale to storm-force W/NW winds will be aimed towards Hawaii, generating a moderate NW groundswell for Monday morning to 6ft+ across exposed breaks before easing off into Tuesday and further Wednesday.
Winds should swing back to the N/NE with strength on Sunday continuing to create average conditions before easing from the NE Monday and then re-strengthening Tuesday and persisting all week. Therefore the outlook in general is pretty average for the coming period.