Gribs update on zezo
Post by iconPost by lucarc | 2020-11-18 | 23:35:21

Hi everyone,

I'm pretty new to this forum, so the topic I'm gonna talk about may already have come up here, and I'm sorry if that's the case. It hasn't since the beginning of the race though, if I'm not mistaken.

Tonight, for the 22:30 CET update of the gribs, the update of the gribs has been stuck up to 135 hours. Below that limit, zezo is proceeding with the previous gribs from 16:30 CET.

This is not the first time this happens, and I've seen no one discussing about that until now. I ask the question now though because with the approach of St Helen, the shortest route evolves a lot with every update, and I like to see its evolution in the next 250 hours.

I guess this issue happens to everyone ? Is there a reason to it ?

If you don't see what my problem is, here is a screenshot of the current update of the gribs, 2 hours after the refresh : https://prnt.sc/vlt43s

Thanks for taking care of zezo btw, this is so helpful, congrats.

commenticon 8 Comments
Post by iconPost by JohnT | 2020-11-18 | 23:48:07
The problem is almost always a delay in NOAA releasing the updated files.
See this thread for an example from last week...
http://sail.zezo.org/forum.pl?tid=8129
Post by iconPost by karriv | 2020-11-19 | 09:59:30
I wouldn't be extremely worried about missing an update (especially the 10:30 or 22:30 updates) for winds beyond 100 hours. Those are anyways quite inaccurate in areas where winds are volatile, and then in the areas where winds are stable, they don't change.
Post by iconPost by zezo | 2020-11-19 | 11:12:09
It seems that the NOAA stopped spooling the gribs after 144h for the 18z last night.
Post by iconPost by milonga2 | 2020-11-19 | 22:22:34
Hi, it's now 23:20 and I still can't see the 18z grib. It should be uploaded at 22:46, am I right ? Am I missing something or should I just wait ? Thanks.
Post by iconPost by zezo | 2020-11-19 | 22:42:32
The entire 18z (384 hours) is available around 00:15 (CET). By 23:30 it's usually only the first 220 hours.
Post by iconPost by milonga2 | 2020-11-20 | 06:59:30
OK, now I understand, I thought each run came at once. Not good news for my sleep though... :o)
Post by iconPost by zezo | 2020-11-20 | 08:05:58
You don't always need the entire forecast. Rigt now 168 to 184 hours are enough to reach the ice limit and check your strategy.

Along the ice limit there is no much choice most of the time, so you usually only need a day or two of forecast. Sometimes there is the possibility of a split in the route and then you have to look further and follow the systems for days to make a choice in the end.

Then comes Cape Horn and the route back North. Which usually offers a lot of choices. Which side of the Falklands, how close to the coast, where is your tacking point in the North Atlantic. And you start waiting for the full data set.
Post by iconPost by milonga2 | 2020-11-20 | 22:18:29
Thanks, nice overview for the different parts of the race. Much appreciated!
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