Questions tagged [gfs]

Global Forecast System

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Where can I find archived NAM/HRRR model runs?

I am looking for archived model runs for high-resolution North American weather models, i.e. NAM and HRRR stretching back 10+ years. Do these exist on the internet? Failing that, what's the next best ...
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4 votes
1 answer
75 views

How to find the altitude above mean sea level of the wind in forecast data such as GFS

I'm looking to retrieve from weather forecasts (such as GFS or HRRR) the U and V component of the wind with respect to some altitude (meters) above mean sea level. To do so, I've implement a ...
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3 votes
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99 views

How much does a global model's accuracy change with the timestep?

I've been working with ICON, ICON-EU and GFS forecasts, and it seems like the temperature results are "close" for the same location, 6 hour forecasts and 120 hour forecasts - MAE: 5.7 and 6....
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1 vote
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What is the vertical offset of geopotential height from ellipsoidal height in GFS?

I would like to compare NOAA GFS (Global Forecast System) geopotential height from ASL and GTOPO30. However, I cannot find vertical offset information in GFS geopotential height. Does anyone know ...
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Determining probability of precipitation from GFS data

Looking at the index files in https://ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/, there's no probability of precipitation (POP) data provided. (There is a ...
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How spatial resolution of a NWP model works?

I would like to know how the resolution of a Numerical Weather Prediction model conceptually works. i.e. "Global Forecast System's forecasts with 0.5° horizontal spatial resolution" "...
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111 views

How to download the GFS 2m Temperature data?

I am attempting to download the 2m temperature forecast from the GFS forecasts archived by AWS's open dataset archive. I am having some issues figuring out the feature name to search for in the file ...
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What is the best way to calculate anomaly of meteorological variables with the (GFS/GEFS) forecast

To calculate the anomaly of a variable (temperature, for example) I need the climatology (at least 30 years) of that variable. Which climatology data source should I use? Should I use the "...
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2 votes
1 answer
206 views

What CRS does GFS use?

I'm trying to reproject GRIB data from NOAA forecasts onto other data using Python and the pygrib and proj packages (among many others). What is the proper Proj string for GFS GRIBs? The projection ...
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Land Use grib2 Table 4.212 download?

The grib2 format has a field listed under table 4.212 giving the land use code. Does anyone know where I can download data containing this field?
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What is the "forecast hour of product"

The NCEP website describes the file naming format of the GFS forecast data. https://www.nco.ncep.noaa.gov/pmb/products/gfs/ What does "forecast hour of product" mean?
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Ice Water Content from GFS file

I am working my way through this paper: http://downloads.hindawi.com/journals/amete/2017/8707234.pdf Equations 10 and 11 require the ice water content. I can't find it in the GFS grib2 file ...
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Difference between GDAS and GFS data

What is the exact difference between GFS 0.25 and GDAS 0.25 data which is available in http://nomads.ncep.noaa.gov/. And are the GFS 0.5 and 1 degree data available in the above url and here the same?...
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4 votes
1 answer
469 views

How averaging works in GFS model from NOAA?

We have downloaded grib2 files for GFS model from NOAA and extracted irradiance (Downwards shortwave radiation flux) data. Following is a sample output for cordinates at [52.0,4.0]: ...
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2 votes
2 answers
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How do I convert a latitude/longitude coordinate to a NOAA GFS grid cell location?

Looking at this GFS http://nomads.ncep.noaa.gov:9090/dods/gfs_0p50/gfs20170707/gfs_0p50_12z.ascii?tmax2m[0:2][124:128][279:283] The range defined by the second and third set of brackets specify the ...
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ISA Model and GFS data

I have a newbie question... I always used the International Standard Atmosphere model whenever I needed to calculate the temperature in a given altitude. It always looked accurate to me... However,...
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8 votes
1 answer
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What is the difference between GFS analysis and GFS forecast data?

gfsanl_3_20151201_0000_006 means that the analysis was made at 0000 UTC and is valid at 0600 UTC, doesn't it? But for how long, 3 hours? And what is the difference ...
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How to find Cloud cover data in GFS grib models

I've been looking for the cloud cover estimates provided in the NOAA GFS models. This page discusses all their weather products and one of the few I find that includes cloud cover data "Total Cloud ...
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2 votes
1 answer
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upper air data(observation) and analysis step for GFS model

Global forecast systems(GFS) gives analysis and forecasts at different time steps. Their main source of input is upper air data which is recorded only twice in a day(observation comes at 00 and 12). ...
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7 votes
0 answers
636 views

Why did the GFS switch to hourly forecasts through hour 120?

About a month ago, the GFS was upgraded. Among other things (like making parallel GFS data available), the upgrade notice said: Include hourly forecasts out to 120 hr Now, this seemed ...
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9 votes
1 answer
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What is the difference between the freezing level and 0 C isotherm in NOAA's GFS?

I'm playing around with NOAA's GFS forecast data and I see that it contains both a "0 °C isotherm level" and a "Highest tropospheric freezing level". Could someone tell me the ...
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