10
votes
What is the difference between GFS analysis and GFS forecast data?
I'm no expert at this, I've just been working with a variety of gfs gribs for a while now. The only thing I know about them is what I've read and I'll cite them here. I don't know where you got ...
- 301
5
votes
Accepted
How averaging works in GFS model from NOAA?
The GFS is a model, and the model have a given time-step equal or smaller than the time-step of the output, that in this case is 3 hours. Different processes can be computed using different or even ...
- 17.7k
4
votes
Accepted
How to find the altitude above mean sea level of the wind in forecast data such as GFS
It makes sense, some locations have a surface pressure under 1000 mb... which means to get to 1000 mb you'd have to go below ground (the basic idea of the calculation is that pressure decreases as you ...
- 8,802
3
votes
Accepted
What CRS does GFS use?
My ansatz for what cyl means is likely Equidistant Cylindrical Projection, because in the older Basemap module, 'cyl' was the ...
- 8,809
3
votes
Accepted
What is the "forecast hour of product"
The forecast hour of the product is the hour after the model cycle runtime that the forecast is valid at. For example, if the the cycle runtime is 12Z and the forecast hour is 9, then the the forecast ...
- 181
2
votes
Accepted
Understanding GFS Parameter Averaging Times
These GFS parameters are stored as a running average, reset every 6 hours. This is a bit unusual and requires some special handling to get back to hourly forecasts.
The value you have, time-tagged 03:...
- 136
2
votes
Accepted
How spatial resolution of a NWP model works?
Yes, the deterministic GFS model (one model) has higher spatial resolution than the GEFS models (31 models). That is, that the latitude and longitude of the entire world is incremented by 0.25° in the ...
- 8,809
1
vote
Where can I obtain the raw atmospheric data that weather forecast images are based on?
You can fetch GFS from NCEP servers directly. It is documented here:
https://www.nco.ncep.noaa.gov/pmb/products/gfs/
For example, if you want today's 06 UTC run in 0.25-degree resolution, you would go ...
- 451
1
vote
Where can I find archived NAM/HRRR model runs?
You may be able to find success for the HRRR at either CHPC U of Utah or via Amazon Web Services (if I remember right, AWS typically has data access charges that you may be able to get around for ...
- 8,802
1
vote
Accepted
What is the vertical offset of geopotential height from ellipsoidal height in GFS?
I have found the answer
Geopotential height of ground or water surface is available as a variable (UCAR variable inventory).
It is called 'orography' if you read the file with cfgrib. Somehow it did ...
- 21
1
vote
How to find Cloud cover data in GFS grib models
This is not an explicit answer but might give you an idea. The US National Weather Service forecasters use a tool called GFE to create gridded forecasts, largely starting from raw model data. For most ...
- 96
1
vote
upper air data(observation) and analysis step for GFS model
You are right that upper air soundings are typically only done twice a day, and even at quite a coarse observation spacing.
And that upper air data is definitely very important in models.
I'd ...
- 8,802
1
vote
Ice Water Content from GFS file
There is a parameter ice water mixing ratio in the gfs.t<hour>z.pgrb2.0p25.f<step> file given at isobaric levels.
- 338
1
vote
Difference between GDAS and GFS data
From this page: https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gfs.php
As I understand, The Global Data Assimilation System (GDAS) is just that, an assimilation system. It takes in ...
- 41
1
vote
How do I convert a latitude/longitude coordinate to a NOAA GFS grid cell location?
The coordinates defined in Global Forecast System (GFS -0.5º Degree) data defined somewhat unusual. In the GFS, longitudes and latitude contains 720 and 361 values respectively. Therefore to convert ...
1
vote
How do I convert a latitude/longitude coordinate to a NOAA GFS grid cell location?
** All of the links given with times will need to be adjusted to current dates if reading this at later times or else will appear dead **
Once upon a time I dealt with such files, but not in quite a ...
- 8,802
1
vote
Accepted
ISA Model and GFS data
I would agree with your hypothesis, but I must point out that it will likely break down further and further as you approach the tropopause. Whether the ISA model is actually a average, I cannot say. ...
- 8,809
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