Forecast Systems

Weather and atmospheric forecast data can be obtained from the following forecast systems:

Global Forecast System (GFS)

gfs4cThe Global Forecast System (GFS) is a global numerical weather prediction system produced by the National Centers for Environmental Prediction (NCEP) and run by the US National Weather Service (NWS).  GFS provides global forecasts four times a day with an approximate horizontal resolution of 27km for the first 8 days and 35km for days 4 to 16. In the vertical, the model is divided into 64 layers with 139 variables.  The model produces forecast output every hour for the first 24 hours, every 3rd hour for days 2 to 8, and every 12 hours after that. In 2014, model system upgrades will increase grid resolution to 13km out to 10 days. Data is accessed via NOMADS, the National Operational Model Archive and Distribution System.
1. Home Page
2. Intro to NOMADS
3. NOMADS User Manual
4. NOMADS Model Data Inventory
5. Data: NOMADS Portal
6. Data: Direct FTP
7. Data: HTML
8. Data: OPeNDAP

Global Ensemble Forecast System (GEFS)

ncep_logoThe Global Ensemble Forecast System (GEFS) is a weather forecast model made up of 21 separate forecasts, or ensemble members. The National Centers for Environmental Prediction (NCEP) started the GEFS to address the nature of uncertainty in weather observations, which are used to initialize weather forecast models. With global coverage, GEFS is produced four times a day with weather forecasts going out to 16 days. Gridded data are available through NOMADS.
1. NOMADS User Manual
2. NOMADS Model Data Inventory
3. Data: NOMADS Portal
4. Data: Direct FTP
5. Data: HTML
6. Data: OPeNDAP

NCEP North American Mesoscale Forecast System (NAM)

NAMlogoThe North American Mesoscale Forecast System (NAM) is one of the major weather models run by NCEP to provide mesoscale guidance. Dozens of weather parameters are available from the NAM grids, including surface wind vectors by level and surface  radiation flux fields.  Currently, five nested domains are being run, two large domains (CONUS, Alaska) and three small domains (Hawaii, Puerto Rico, Guam).  The gridded data are available for download through satellite feeds, FTP servers and NOMADS.
1. Home Page
2. Forecast Products
. Operational Graphics

4. Direct FTP: Server Directory
5. Direct FTP: NAM Forecast Grids
6. Direct FTP: RAP Forecast Grids
7. Direct FTP: 32km Tiled Output
8. Direct FTP: 12km Tiled Output

NCEP Rapid Refresh (RAP-V2)

ESRLlogoThe Rapid Refresh model is an hourly-updated short-term operational weather prediction system covering North America that replaced RUC starting 1 May 2012. Implementation at NCEP of RAP Version 2 occurred on 25 Feb 2014.  The latest version of Rapid Refresh uses uses a RAP-configuration of the WRF model with the ARW core(see below).  NCEP implementation of an experimental 3km High Resolution Rapid Refresh (3kHRRR) is currently planned for August 2014.
1. Home Page
2. RAP Product List
3. Direct FTP: RAP Data

NCAR ARW Weather Research and Forecast (WRF) Model

wrf-model-logoThe Weather Research and Forecasting (WRF) model is a next-generation mesoscale numerical weather prediction system designed by NCAR to serve operational forecasting and atmospheric research needs. NCAR data sets include a 72h forecast for the continental U.S. in 15 km resolution and daily imaging at 3-4 km resolution.
1. Home Page
2. Technical Notes
3. WRF ARW Source Code
4. Data: 15km CONUS Forecast

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