## Meteorology / ARL Data FTP

The ARL web server contains several meteorological model data sets already converted into a HYSPLIT compatible format in the public directories. Direct access via FTP to these data files is "hardwired" into the GUI. The data files are automatically updated on the server with each new forecast cycle. Only an email address is required for the password to access the server. The "FTP menu" is locked until the FTP process is completed, at which point a message box will appear indicating the file name that was just transferred.

Note that the NOAA models run by NCEP may be at higher spatial resolution than what is archived in a HYSPLIT compatible format on the ARL server. If calculations using higher resolution data are required, then the original GRIB encoded files must be obtained and converted as described in the data conversion section. GRIB decoding can be difficult. Although the required software is provided through the GUI, the large file size downloads may limit the practical application of these real-time data files.

### Meteorology / Data FTP / Current Forecast

Forecast data are available for NOAA's North America Model (NAM), the Global Forecast System (GFS), and the Rapid Update Cycle (RUC) at various resolutions, projections, and forecast time durations. The files are updated at two to four hours after the cycle time. Forecast files are available for the last several days depending upon the server and not all files are on all FTP servers. All forecast files follow the same file naming convention of hysplit.t{cycle}z.{name}, where cycle represents the initial UTC time of the forecast (00,06,12,18) and the names are as follows:

- gfsf :: 1-deg 3P +180h (580 Mb) global forecast at one-degree resolution at 3 hour intervals at pressure levels out to +84 hours
- gfslrf :: 2.5d 12P +360h (30 Mb) long-range global forecast at two and half degree resolution at 12 hour intervals at pressure levels and from forecast hours +180 to +360.
- namakf :: 45-km 3P +36h (39 Mb) regional forecast extracted for Alaska at 45 km resolution every three hours on pressure levels only out to +36 hours.
- namf :: 12-km 3P +48h (881 Mb) regional forecast for the entire domain at 12 km resolution every three hours on pressure levels out to a +48 hours.
- namf40 40-km 3P +84h (150 Mb) regional forecast for the entire domain at 40 km resolution every three hours on pressure levels out to a +84 hours.
- namsf.AK :: 12-km 1S +48h (1297 Mb) regional forecast extracted for Alaska at 12 km resolution at hour intervals on sigma surfaces out to +48 hours.
- namsf.HI :: 12-km 1S +48h (145 Mb) regional forecast extracted for Hawaii at 12 km resolution at hour intervals on sigma surfaces out to +48 hours.
- namsf.{XX}tile :: 12-km 1s +48h (229 Mb) regional forecast extracted for the XX quadrant of the US at 12 km resolution at hour intervals only for sigma surfaces below 0.6777 out to +48 hours. Quadrants are available for the northeast (NE), southeast (SE), southwest (SW), and northwest (NW).
- ruc :: 20-km 1P +12h (152 Mb) for the CONUS is at 20 km resolution at hourly intervals on pressure surfaces but only out to +12 hours. Updated every three hours.

### Meteorology / Data FTP / Appended Forecast

The appended forecast files consist of a special time extraction of the previous seven (-48 hr) forecast cycle files to create a series of pseudo-analysis (0-hour initialization) and short-time (+3 h or +1,+2,+3,+4,+5) forecasts that have been appended to each other to create a continuous data time series for the previous 48 hours in a single file. These special time extracts are only available for the following files.

- gfsa :: 1-deg 3P -48h (160 Mb)
- namaka :: 45-km 3P -48h (47 Mb)
- nama :: 12-km 3P -48h (829 Mb)
- nama40 :: 40-km 3P -48h (83 Mb)
- ruca :: 20-km 1P -48h (60 Mb)

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