Thursday, January 19, 2017

Thursday 1 19 17 morning call

A lovely longboard solo session marked my return in the water yesterday. I think Tuesday was the first day I had to take off the water in this winter due to injury (and it wasn't even strictly necessary). Pretty stoked about that, considering that last year I spent most of the winter dry (three long months) due to a rib injury. Life is good.

Windsurfing looked pretty bad for my taste (strong and gusty because of the offshore direction), so I wisely sat and took photos of my friends before going to work. Here they are in chronological order.

Bernd Roediger.

Jake Miller.

Steve Sadler.

Jason Hall.

Matt Pritchard.

Casey Hauser.
4am significant buoy readings
South shore
2.5ft @ 17s from 282° (WNW)

That is the WNW wrap, check the usual NW buoy to Maui travel time and shadowing angles post if you want to assess your chances of surfing in the Kihei side. If you can't be bothered, do check the webcams instead.

North shore
11.5ft @ 15s from 295° (WNW)

11.4ft @ 15s from 308° (WNW)

8.6ft @ 17s from 312° (NW)           
5.2ft @ 13s from 314° (NW)

5.8ft @ 17s from 314° (NW)
3.8ft @ 11s from 334° (NNW)
The "mistery" of the absence of the signs of the swell at the NW buoys yesterday morning was explained with their usual lack of sensitivity to the small long period energy. The local buoys are much better at detecting those, and my guess is that is because they live in relatively calmer waters. They might just be more technically sophisticated too, I have no idea.

Anyway they finally went up once the energy got significant in the 15-16s range and the NW101 peaked around 4pm (red arrow).
Here I NEED to elaborate about the travel time again and offer you a revised version of GP's rule of thumb for calculating it.
As you can see from the post I linked above, I based my calculation on the NW buoy to Oahu distance indicated in the Surfline article and just added 100nm for Maui: 255 + 100 = 355. Well, that wasn't too precise, since the real distance is 383nm instead, as the Google Earth image below shows.
Here's the new table, still based on those four speeds indicated in the original Surfline article. Got no time this morning to verify them and to come up with a new rule of thumb, I'll try to do that later. Help from the readers appreciated.

20sec--30kts--12.7 hrs

17sec--26kts--14.7 hrs

14sec--21kts--18.2 hrs

11sec--17kts--22.5 hrs

Back to our swell, the new table suggests that 15s deep water waves will take more like 17h to make to Maui, and that would imply a peak around 9am. But the waves do slow down in more shallow waters, so it might even be a little later than that.
Let's talk about size now. The Pauwela 4am reading was  5.8ft @ 17s from 314° (NW). In the meantime that I was researching all of the above, the 5am reading became available: 6.3ft @ 17s from 312° (NW). That is a confirmation that the swell is still building. Surfline's highest part of the graph (not necessarily the peak, since every point is spaced every 6 hours) is at 8am with 10.6f 15s from 313. That is definitely possible, also considering that in the meantime Waimea went up to 10.5ft @ 17s from 314° (NW).

6f 17s is already over my Hookipa limit (it's good to know these things, specially if you want to decide where to go before the sun rises) as it will offer some solid double overhead + sets. I'm a little perplexed because I don't hear the noise from the ocean I would expect with such size. That could be due to two factors, both true:
1) because the original direction is around 295 and the Hookipa to Molokai shadow line is 305, the sets will be less consistent than a unblocked swell. Less sets make less noise.
2) the shadow line of the Pauwela buoy is instead 299 (see image below), so the buoy might be getting a bit more energy than Hookipa.

Current wind map shows:
1) a wide but really weak NW fetch. A bit of a day of pause in the wave generation machine as the strong fetch associated with today's swell (circled in blue) has now moved north of us and it's aiming its fury towards the west coast. 31f 16s from 284 if the scary open ocean forecast for Monterey. I wonder if Mavericks is surfable at that size. My guess is not.
2) a small not well oriented fetch down south

NAM3km map at 7 shows light sideoff trades. The later maps don't change much, but I really don't like that you can't zoom in anymore without screwing up everything. If someone has time to report the bug, there's a procedure explained on their website. Thanks for that.
In the meantime, check the MC2km maps when updated (link n.17) because they are way more reliable.

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