Friday, February 17, 2017

Friday 2 17 17 morning call

Not easy to find a place with clean waves yesterday, since the wind was on it almost everywhere. I ended up doing a fun SUP session in Kihei where the waves were up to chest/shoulder high. I told you to check the webcams...

No photos from yesterday, this is my friend Kazuma Saita at the Bay a while ago in a photo by Noah Garrett.

4am Significant buoy readings
South shore

3.5ft @ 13s from 272° (W)
Scroll below to yesterday's post to compare this reading to yesterday's and you'll see that today Kihei should have similar, just a tad (or more correctly a second) smaller waves. Check the webcams.

North shore
4.8ft @ 12s from 291° (WNW)
3.6ft @ 10s from 316° (NW)

5.4ft @ 13s from 325° (NW)
3.3ft @ 10s from 331° (NNW)

4.6ft @ 13s from 330° (NW)
As predicted, the WNW swell is lasting many days and it's now down to more manageable levels. Below is the graph of the NW101 and Pauwela buoys. As pointed by the red arrow, the swell went back to a more westerly direction up at the first one. The explanation of that is in what the fetch did, which is something you can check by scrolling down to the old posts. Or you can try to remember the fetches I post daily in the Current Wind Map section. Practice that now because the buffer of maps you need to remember in winter time is only 3-4 days. Gonna be harder in summer time with 7-8 days to keep in mind...

At 12s, the waves take ROUGHLY 20 hours from the NW buoy to here, so by looking at what happened at the NW buoy in the last 20 hours, you can have an idea of what's gonna happen here locally today: a more steady decline, but I wouldn't call it a dying swell just yet. Not with 4.6f 13s in the local waters. I''ll post a beach report at 6.30am from the lookout (where I'll meet my surf guide customer), but I can anticipate you that Hookipa will be really fun size and clean.
Maybe it makes more sense to talk about the wind now, since it's so important for the quality of the waves, so here we go. I'm still looking for the best option for a wind prediction model that is available at the time I do this call. My favorite MC2km website is based on the most reliable WRF model, but is updated very irregularly (and I will never understand why, since it should be a completely automatic process). Another decent one is the HRW (sorry if I often confused it with the WRF), but its Windguru table does not give an idea of the wind distribution around the island.

And that's why I tend to use the Windity maps. For the short term closeups, three models are available:
- NAM3km
- ECMWF9km
- GFS22km

Those km numbers are the resolution at which the models calculate the wind. Now you would think that a model with a resolution of 3km (wind predicted for every point of a grid of 3km wide cells) would be more precise of a model with a resolution of 9km, but that might not necessarily be the case.

Below is the ECMWF (also knows as the European model) prediction for 7am and it seems to be much more in line with what the Hookipa sensor is reading while I write this at 5.30am.
Quite a bit stronger wind predicted for the same time by the NAM3km model, fortunately that's not the case.
The euro model at 2pm shows very good conditions still.
While the NAM one shows a bit more wind. I'll keep an eye on both in the next few days to try to determine which one is more reliable. Sorry about all these maps, but that's what it is.
You know what? I'll send an email to the windity guy and ask him to incorporate the HRW model for Hawaii. Let's see what he thinks.
Current wind map shows:
1) a newly forming fetch coming off Japan
2) that is the start of the fetch that will generate the next swell on Sunday/Monday. It'll be more clear tomorrow and it will be very close to us. That usually means shorter periods, high consistency and rougher conditions. But in the end the conditions will depend on the local wind which, unfortunately, it's gonna be unfavorable starting Saturday afternoon.
PS. A felt a little earthquake at 5.34am while I was writing this.

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