If NCOM files are not available contact Bob Daniels at
robert.daniels@noaa.gov and cc:NCEP.List.OPC-support@noaa.gov. Monday - Friday (9 - 5:30 Eastern Time).
Nights and weekends or if Bob is not available contact the Senior Duty Meteorologist
at 301-683-1500 or SDM@noaa.gov.
On December 18, the NCOM files will be named differently as part of the Navy's move to COAMPS (Coupled Ocean Atmosphere Mesoscale Prediction System), a common software framework FNMOC is moving toward to run all operational regional models (ocean, atmosphere, and eventually wave and ice).
The underlying data-assimilation and forecast models remain unchanged, so the model solution performs with the same level of skill as the previous output.

Key for the New File Format: 
The old file name convention is as follows.

The old tar files are named:

 

ncom_relo_$REGION_$DTG.tar.gz

 

where:

     $REGION is the model area

     $DTG is the date time group

 

For example, the tar file for the alaska_u region for October 5 is

 

ncom_relo_alaska_u_2020100500.tar.gz

 

The old NetCDF file name convention is as follows.

 

ncom_relo_$REGION_$DTG_$TAU.nc

 

where:

     $REGION is the model area

     $DTG is the date time group as YYYYMMDDHH

     $TAU is the forecast tau as HHH

 

For example,  the file names for alaksa_u for October 5 will be as follows

 

 ncom_relo_alaska_u_2020100500_t000.nc

 ncom_relo_alaska_u_2020100500_t003.nc

 ncom_relo_alaska_u_2020100500_t060.nc

…

 ncom_relo_alaska_u_2020100500_t096.nc

 

The new file name conventions are as follows.

 

The tar files are divided into 24-hour groups, such that taus 0-24 are in one file, taus 25-48 in another, etc.  For example, the following tar files were used for the alaksa_u model for October 4.

 

alaska_u_ocn_ncout_grid1_2020100400_t0000-0024.tgz

alaska_u_ocn_ncout_grid1_2020100400_t0025-0048.tgz

alaska_u_ocn_ncout_grid1_2020100400_t0049-0072.tgz

alaska_u_ocn_ncout_grid1_2020100400_t0073-0096.tgz

 

The new name convention for the NetCDF files are as follows.

coamps_ncom_$REGION_ 1_$DTG_$TAU.nc

where:

     $REGION is the region name for the model

     $DTG is the date time group as YYYYMMDDHH

     $TAU is the forecast tau HHHHMMSS

 

For example: for region alaska_u on October 5, the file names will look like the following.

 

./coamps_ncom_alaska_u_1_2020100500_00000000.nc

./coamps_ncom_alaska_u_1_2020100500_00030000.nc

./coamps_ncom_alaska_u_1_2020100500_00060000.nc

./coamps_ncom_alaska_u_1_2020100500_00090000.nc

…

./coamps_ncom_alaska_u_1_2020100500_00960000.nc

Old File Details but apply to new files also: 
NCOM files found here in http://ftp/opc.ncep.noaa.gov/grids/operational/NCOM/regional are in
NetCDF format and include:

http://ftp/opc.ncep.noaa.gov/grids/operational/NCOM/regional/ are in
NetCDF format and have a resolution of 1/30 degrees (~3.6 km)
The files include surface variables and variables for the entire
water column. The variables included are water temperature, currents,
salinity, surface atmospheric pressure, model surface temperature flux, model
surface salinity flux, model surface shortwave flux, model surface roughness,
surface wind stress and water surface elevation.
The new regional files are available daily by 21:30 UTC (5:30 p.m. EDT).
The new files include one tarred and zipped file for each of the 3 regions
that each contain 25 files: one file for each forecast hour from the 0 hour
nowcast through the 72 forecast at an interval of 3 hours. The Gulf of Mexico
and Alaska region files contain forecasts out to 96 hours at a 3 hour interval for a total
of 33 files in each region. They are split into A,B,C, D tar files for each forecast day.

The files found here are:
ncom_relo_amseas_YYYYMMDD00_A.tar.gz - ncom_relo_amseas_YYYYMMDD00_D.tar.gz -
        American Seas file including the Gulf of Mexico:
        5N-32N, 98W-55W. After unzipping and untarring the 33 files are named
        ncom_relo_amseas_u_YYYYMMDD00_t0ff.nc
ncom_relo_useast_u_YYYYMMDD00.tar.gz - US East Coast: 20-42N, 82-64W. After
        unzipping and untarring the 25 files are named
        ncom_relo_useast_u_YYYYMMDD00_t0ff.nc, where ff is the forecast hour.

ncom_relo_socal_u_YYYYMMDD00.tar.gz - US California Coast: 25-40N, 125-111W.
        After unzipping and untarring the 25 files are named
        ncom_relo_socal_u_YYYYMMDD00_t0ff.nc, where ff is the forecast hour.

ncom_relo_haw_YYYYMMDD00.tar.gz - Hawaii: 15-29N, 166W-152W. After unzipping
        and untarring the 25 files are named ncom_relo_haw_YYYYMMDD00_t0ff.nc, where
        ff is the forecast hour.

ncom_relo_alaska_u_YYYYMMDD00.tar.gz - Alaska:36.5-62N, 170W-120W. From the
        California Coast near Monterey North to 62 N in the Bering Sea. After unzipping
        and untarring the 33 files are named ncom_relo_alaska_u_YYYYMMDD00_t0ff.nc,
        where ff is the forecast hour.