Tuesday 12 1 20 morning call

Hookipa yesterday morning. Tanner Hendricks, always dynamic and fun to watch.

6am significant buoy readings and discussion.
South shore
Lanai
1.2ft @ 14s from 187° (S)

Very small southerly energy at Lanai, check the Lahaina webcam if interested, for size, conditions and consistency.

North shore
NW101
4ft @ 23s from 328° (NW)

Waimea
2.5ft @ 14s from 345° (NNW)

Mokapu
3.4ft @ 9s from 53° (ENE)

First XL swell of the winter is hitting the NW buoys with an impressive 4ft 23s. Let's see how Pat Caldwell described the evolution of the fetch:
A winter-caliber low pressure system formed east of the Kuril Islands Saturday 11/28 with central pressure dropping to near 960 mb. The system moved steadily east near 47N with peak winds to hurricane force near the center and a wide circulation of severe gales to storm-force winds stretching over a vast region. The center crossed the Date Line Sunday PM 11/29 then continued east to 168W into 11/30 as it occluded.

When a wave-generating weather pattern travels in a similar direction at a similar speed to a growing swell, it is called captured fetch. The high swell continues to receive wind stress from the strongest portion of the weather system, allowing continued wave height increase. For winds severe gale to storm-force winds, it takes about 2 days over near 1000 nm in order to reach fully-developed seas, or the maximum wave heights possible of a given wind strength. The captured fetch phenomenon allows an apparent fetch duration and length to reach this criteria.

He then goes on and describes in great detail all that there is to say about this swell, so I encourage you to do two things:
1) to go on his page and read it
2) to email nws.srd.feedback@noaa.gov and ask for that page to remain there (NOAA is planning on deleting it starting Jan 1st).

Below is the collage of the maps of Nov 28 through 30 that will help follow the above description.

Let's talk local timing now. Below is the table posted in the post Buoys to Maui travel times and Maui's shadow lines that shows the travel time from the NW buoys to Maui. It also explains what I called GP's rule of thumb which, in this particular case of such high period, is not applicable.

From the table you can see that the travel time at 23s is in fact around 11h and so those 4ft 23s should be here around sunset. Below is the graphs of NW101 and Waimea together with the Surfline forecast. As usual the timing of this one seems to be around 12h late, so I drew a red dotted line on Waimea's empty graph to show when I think the swell will pick up in Maui: in the afternoon. Hookipa should be well overhead by sunset and completely maxed out and unsurfable tomorrow and for a couple of days.

As far as the morning goes, I'll call the usual head to possibly overhead high waves and clean conditions all morning.

Wind map at noon .The other ones can be found at link n.-2 of GP's meteo websites list in the right column (click on animation of the 10 meter column).

Fetches map (circles legend: red: direct aim, blue: angular spreading, black: blocked, yellow: apparent direct aim, but out of the great circle ray map, so not 100% sure).
North Pacific (about 4 days travel time from the NW corner of the North Pacific):

South Pacific (about 7 days travel time from east/west of New Zealand):

Morning sky.