[python #WZY-206437]: GFS 0.25 forecast data access

Greetings!

So the problem here is how NCEP sends out the data. They are sending out these 
fields with a mix of 3-hour and 6-hour periods. You can see this in the 
`time3_bounds` (or something similar) which gives the start and end times for 
the relevant period.

For some data I just downloaded, it looks like:

  data=[[ 78.,  84.],
        [ 84.,  87.],
        [ 84.,  90.],
        [ 90.,  93.],
        [ 90.,  96.],
        [ 96.,  99.],
        [ 96., 102.],
        [102., 105.],
        [102., 108.]],

where the values are hours since the start of the forecast period. Thredds, 
when trying to present these as a single "time" uses the midpoint of the 
period, which is likely why the values seem to be not as expected. The end 
values are spaced every 3 hours as you expected.

For more information on mixed interval variables, I'd recommend reading this 
support post:

  https://www.unidata.ucar.edu/support/help/MailArchives/thredds/msg02568.html

Hope this helps!

Ryan

> Thank you for your assistance. I managed to get it right.
> 
> I  have another question : I managed to download the following
> parameters : Total
> cloud cover (Mixed_intervals Average) @ Entire atmosphere and Downward
> Short-Wave Radiation Flux (Mixed_intervals Average)
> 
> i am a bit confused about the time steps , i was of opinion that data is
> available at 00:00; 03:00; 06:00; 09:00; 12:00;15:00;18:00;21:00 UTC
> 
> i got the following :
> [image: image.png]


Ticket Details
===================
Ticket ID: WZY-206437
Department: Support Python
Priority: Low
Status: Closed
===================
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