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2/01/2019 10:33 am  #1


WeatherGrib Time Stamp

Is there a way to tell the "Time Stamp" of the grib (what you would get if you hit Check Time)
after the grib has already been downloaded?

 

2/01/2019 3:09 pm  #2


Re: WeatherGrib Time Stamp

If you open the file, the first valid time can be seen at the top left of the chart (if you are at the beginning of the file)

 

2/01/2019 5:29 pm  #3


Re: WeatherGrib Time Stamp

just be careful with predict wind - if you download the GFS or EC from them, they don't give you the first forecast times - i think they omit f00 and f03.
their reasoning is that those models are not available til ~6hrs (EC a little more) after f00, so the average user doesn't need forecasts for times that have passed.
i see that.., but find that i have difficulty with their gribs knowing what the run time is 
i asked them to make omitting those time steps optional.., or to put the run time in the file name - they said they would think about it...
what i said to them, was something  like - sure, in principle, i can figure it out.., but i am downloading these things in the middle of the night, maybe the weather is rough and i'm tired.., i just want to know for sure what the run time is.., please can't you just make it easy for me? but i don't think they get it.
i guess their typical customer isn't concerned with things like that...

Last edited by us7070 (2/01/2019 5:31 pm)

 

2/01/2019 6:45 pm  #4


Re: WeatherGrib Time Stamp

PW are working on a new release so now is the time to put in your suggestions.
I only subscribed to get the ECMWF model which I can no longer do.  So they may be adios.
Subjective/Minimal Sample Side Not withstanding, Tidetech current data did not seem to be any more accurate then RTFOS.  So maybe dump them too.  Any other opinions appreciated.

Nick, thank you for the suggestion to see the time in the upper left.  But if I have an RTFOS grib loaded and a Wind grib loaded I appears to show the earlier of the two.  Just a thought but it would be nice to have it as part of the file name or listed in the summary of the route.  I know I have downloaded the same grib over and over again as I am never sure I have the latest.  I have the luxury of broadband mostly so no biggy.  But trying to think ahead.  
 

     Thread Starter
 

2/01/2019 6:49 pm  #5


Re: WeatherGrib Time Stamp

The Check VT functions before download in Exp are the initialisation/analysis time so whether you start at H00 or H03 doesn't matter.

It is why the Hxx field is displayed next to the display time in Exp. I've also recently added it to the meteogram table.

The Exp WRF grib files start at H03 for similar reasons too. It reduces the file size and also the earlier times are mostly just interpolations of the GFS so aren't of as much use.

 

2/01/2019 7:20 pm  #6


Re: WeatherGrib Time Stamp

After some investigating, you are correct. However, the time returned by the Exp VT function for Predictwind gives the first valid time. That should be easy to use even though it is H03? It seems they only update GFS every 12 hours though.

However, it seems all the times in the Pw GFS grib files are messed up. For example, the Exp meteogram shows all forecasts are H00.


Saildocs is by far the best of the GFS sources though, so normally I recommend using that. They also supply it every 6 hours at 0.25 resolution too. With FV3, there will hopefully be less reason for EC anyway.

Last edited by Nick (2/01/2019 7:21 pm)

 

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