Operational Forecast System (OFS) Frequently Asked Questions (FAQs)

Below is information on each OFS, including the daily run schedule (in UTC) for the current OFS that are operated on the NOAA Weather & Climate Operational Supercomputing System (WCOSS2). Model output files are first posted on the NOAA Operational Model Archive and Distribution System (NOMADS).

OFS Name	Full OFS Name	Core Model	Cycles/Day	Cycle Hours	Length of Nowcasts (hrs)	Length of Forecasts (hrs)	Temporal Resolution of Fields	Start Time of Cycle (UTC)	Post Time on NOMADS (UTC)
CBOFS	Chesapeake Bay OFS	ROMS	4	00,06,12,18	6	48	Hourly	[00|06|12|18]:42	[01|07|13|19]:22
CIOFS	Cook Inlet OFS	ROMS	4	00,06,12,18	6	48	Hourly	[00|06|12|18]:50	[01|07|13|19]:45
DBOFS	Delaware Bay OFS	ROMS	4	00,06,12,18	6	48	Hourly	[00|06|12|18]:40	[01|07|13|19]:10
GoMOFS	Gulf of Maine OFS	ROMS	4	00,06,12,18	6	72	Every 3 hours	[01|07|13|19]:00	[01|07|13|19]:25
LEOFS	Lake Eerie OFS	FVCOM	4	00,06,12,18	6	120	Hourly	[01|07|13|19]:50	[02|08|14|20]:15
LMHOFS	Lake Michigan and Huron OFS	FVCOM	4	00,06,12,18	6	120	Hourly	[01|07|13|19]:50	[02|08|14|20]:30
LOOFS	Lake Ontario OFS	FVCOM	4	00,06,12,18	6	120	Hourly	[01|07|13|19]:50	[02|08|14|20]:20
LSOFS	Lake Superior OFS	FVCOM	4	00,06,12,18	6	120	Hourly	[01|07|13|19]:50	[02|08|14|20]:40
NGOFS2	Northern Gulf of America OFS	FVCOM	4	03,09,15,21	6	48	Every 3 hours	[03|09|15|21]:00	[04|10|16|22]:10
SFBOFS	San Francisco bay OFS	FVCOM	4	03,09,15,21	6	48	Hourly	[03|09|15|21]:25	[03|09|15|21]:50
SSCOFS	Salish Sea and Columbia River OFS	FVCOM	4	03,09,15,21	6	72	Hourly	[03|09|15|21]:50	[04|10|16|22]:52
TBOFS	Tampa Bay OFS	ROMS	4	00,06,12,18	6	48	Hourly	[00|06|12|18]:57	[01|07|13|19]:12
WCOFS	West Coast OFS	ROMS	1	03	24	72	Every 3 hours	03:00	03:18

Below is the daily run schedule (in UTC) for the OFS that are operated on the NOAA/NOS/CO-OPS servers.

OFS Name	Full OFS Name	Core Model	Cycles/Day	Cycle Hours	Length of Nowcasts (hours)	Length of Forecasts (hours)	Temporal Resolution of Fields Output Files	Start Time (UTC)	Post Time on NOMADS (UTC)
NYOFS	New York and New Jersey OFS	Princeton Ocean Model (POM)	4	05,11,17,23	6	48	Hourly	[05|11|17|23]:30	[05|11|17|23]:58
SJROFS	St. John’s River OFS	Environmental Fluid Dynamics Code (EFDC) circulation model	4	05,11,17,23	6	48	Hourly	[05|11|17|23]:50	[05|11|17|23]:55

Each OFS provides guidance over two distinct time periods: a nowcast and a forecast. Nowcasts and forecasts are predictions about the past, present, and future states of water levels, currents, salinity, temperature, and ice concentration.

A nowcast incorporates recent (and often near real-time) observed meteorological and oceanographic data. A nowcast covers the period of time from the recent past (e.g., the past few days) to the present, and it can make predictions for locations where observational data are not available.

A forecast, on the other hand, incorporates meteorological and oceanographic forecasts to make predictions into the future for times where observational data will not be available. A forecast is usually initiated by the results of a nowcast.

Each OFS runs at specific times each day. For example, the Chesapeake Bay OFS (CBOFS) runs four times each day, at 00Z, 06Z, 12Z, and 18Z. Each of these runs is called a cycle. For each of the four cycles, CBOFS produces nowcast guidance from 6 hours prior to the cycle hour up to the cycle hour, and forecast guidance from the cycle hour to 48 hours after the cycle hour.

A CBOFS 12Z model cycle covers, for instance: Different OFS can have different model cycles times for each day, and different forecast guidance lengths. For example, the West Coast OFS (WCOFS) has only one model cycle each day at 03Z, and provides forecast guidance out to +72 hours. The Lake Erie OFS (LEOFS) has four cycles each day at 00Z, 06Z, 12Z, and 18Z, and provides forecast guidance out to +120 hours. See the FAQ section “What OFS do you run, and how often are they updated?” section for more information on cycle times, the length of nowcasts and forecasts for each OFS, and the temporal resolution of fields files.

The stations output files contain modeled results for select locations of interest within the OFS’ domain, and the fields output files contain modeled results for the whole OFS domain.

OFS outputs include time series for water levels, currents, water temperature, and salinity (if applicable) for:

● the selected locations (stations) at 6-minute intervals;

● hourly 2-D fields at the surface (available only when 3-D field output is 3-hourly; see the table in the section “What OFS do you run, and how often are they updated?” for details on which OFS contain this output);

● and hourly or 3-hourly 3-D fields for the entire model domain

While water levels, current direction and velocity, water temperature, and salinity (if applicable) are the main parameters of interest in these output files, they also contain a variety of other parameters used or output by the model runs (see the FAQ section “How can I check the output file parameters and their attributes?” for how to get detailed information on those additional parameters, or see the FAQ sections “More information on FVCOM-based OFS” and “More information on ROMS-based OFS”).

In addition to the stations and fields output files, you can also find available OFS.tCCz.YYYYMMDD.regulargrid.[n|f]HHH.nc output files. These files contain a subset of all the parameters output by the OFS, limited to those of particular interest (i.e., water levels, current direction and velocity, water temperature, salinity, time of the model simulation, depth, etc.). These parameters are interpolated to a regular grid; inverse distance weighted interpolation is used for horizontal interpolation, and linear interpolation is used for vertical interpolation.

Below are methods for how to check the OFS output file parameters and their attributes.

If the NetCDF file is downloaded and saved on a local Unix/Linux server:

use the command "ncdump -h filename" to display all the parameters and their attributes;

If accessing the NetCDF files via the OpenDAP THREDDS:

● Select an OFS and navigate to the year, month, day

● Select the OpenDAP service option to access the data and view all parameters and their attributes

An example of the information provided using the second method is shown below:

The naming conventions for each type of output are listed below:

Stations output: OFS.tCCz.YYYYMMDD.stations.[nowcast|forecast].nc

2-D fields at the surface output: OFS.tCCz.YYYYMMDD.2ds.[n|f]HHH.nc

3-D fields output: OFS.tCCz.YYYYMMDD.fields.[n|f]HHH.nc

3-D fields output on a regular grid: OFS.tCCz.YYYYMMDD.regulargrid.[n|f]HHH.nc

Where OFS is the name of the OFS (e.g. cbofs, sfbofs), CC is the cycle of the day (run cycle, e.g., 00, 06, 12, etc.), YYYYMMDD is the date of the model run (year month day, e.g., 20231219), HHH is the nowcast or forecast hour for fields files(e.g., 001, 002, etc.), and [nowcast/forecast] or [n/f] denotes either the nowcast or forecast results.

The output files are in NetCDF (.nc) format, and the coordinate system of the NetCDF files is NAD83 (North American 1983). Times are in UTC.

Below is a detailed description of OFS output files, using 3-D fields files from the Chesapeake Bay OFS (CBOFS) 06z cycle on March 4, 2025 as an example:

cbofs.t06z.20250304.fields.n001.nc - 3-D fields nowcast file 5 hours before current cycle time (06z, or 0600 UTC)
cbofs.t06z.20250304.fields.n002.nc - 3-D fields nowcast file 4 hours before current cycle time (06z)
…
cbofs.t06z.20250304.fields.n006.nc - 3-D fields nowcast file at the current cycle time (06z)

and

cbofs.t06z.20250304.fields.f001.nc - 3-D fields forecast file 1 hour after current cycle time (06z)
cbofs.t06z.20250304.fields.f002.nc - 3-D fields forecast file 2 hours after current cycle time (06z)
…
cbofs.t06z.20250304.fields.f048.nc - 3-D fields forecast file 48 hours after current cycle time (06z)

Another way to view this time sequence visually is below. For a model run at cycle 06z, or 0600 UTC, the following output files contain model results for these specific times:

NOTE: The n000 fields nowcast file is a duplicate of the final fields nowcast file (n006, for all OFS except WCOFS) of the previous cycle. The f000 fields forecast file is a duplicate of the n006 (for all OFS except WCOFS) fields file of the same cycle. OFS that use ROMS as their core model (such as CBOFS and WCOFS) do not output n000 or f000 to avoid this duplication, while FVCOM-based OFS do output the redundant n000 and f000 files.

Additionally, some OFS output 3-D fields files every 3 hours instead of hourly, which is reflected in the output file names; these OFS also output 2-D surface fields files hourly. See the table in FAQ section “What OFS do you run, and how often are they updated?” for more details on each OFS.

For the same cycle, stations files look like:
cbofs.t06z.20250304.stations.nowcast.nc - 6 minute interval stations nowcast file for the entire OFS run (cycle 06z)
cbofs.t06z.20250304.stations.forecast.nc - 6 minute interval stations forecast file for the entire OFS run (cycle 06z)

There are many options for accessing the native model output of an OFS. The table below lists OFS output data retention details, showing how long the output files are retained in the archives.

For the AWS S3 bucket and NCEI archives, there is a 3-day delay in archiving the data. For the FTP sites, you must access them from a Windows File Explorer window. To use the AWS S3 bucket, you will need to build a script to aggregate/subset the output and derive properties that you are interested in. More information on accessing the data on this archive can be found here: https://github.com/awslabs/open-data-docs/tree/main/docs/noaa/noaa-ofs-pds

Output Type	NOMADS Data at NCEP and NCEP FTP	CO-OPS THREDDS Data Service	AWS NOAA Open Data Dissemination S3 Bucket	NCEI THREDDS and NCEI Web Service*
Station nowcast and forecast files	Most recent 24 hours	Most recent 31 days	Most recent 2 years	>5 years
3D field nowcast file	Most recent 24 hours	Most recent 31 days	Most recent 2 years	>5 years
3D field forecast file	Most recent 24 hours	Most recent 31 days	Most recent 2 months	None
2D surface layer field nowcast file**	Most recent 24 hours	Most recent 31 days	Most recent 2 years	>5 years
2D surface layer field forecast file**	Most recent 24 hours	Most recent 31 days	Most recent 2 years	>5 years
3D fields on a regular grid	Most recent 24 hours	Most recent 3 days	Most recent 3 days	None

* These archives also contain files from retired OFS such as NGOFS, NEGOFS, CREOFS, and NWGOFS.
**Hourly 2D surface layer fields files are only available for OFS that output 3-hourly 3D fields files (WCOFS, GoMOFS, and NGOFS2)

NOTE: As of January 1, 2025, the file directory structure on the AWS S3 bucket is /OFS/netcdf/YYYY/MM/DD, where

OFS refers to the name of the model (e.g., cbofs, dbofs, etc.)

YYYY refers to the year of the model run (e.g., 2024)

MM refers to the month of the model run (e.g., 08)

DD refers to the day of the model run (e.g., 25)

Previously, the file directory structure was OFS/netcdf/YYYYMM, where one single folder contained all the model output files for the month, resulting in over 7000 files.

The output file’s timestamp contains information on when the OFS was run, i.e., run cycle date (YYYYMMDD). The nowcast or forecast hour in the output file name provides time information on the model simulation results by describing the number of hours before (for nowcasts) or number of hours after (for forecasts) the run cycle time. See the FAQ section “What is the OFS model output file naming convention?” for more information on the relationship between the file’s timestamp and the model simulation time for the results.

ROMS-based OFS

For ROMS-based OFS, you can run the following command to find the simulation (or “ocean”) time corresponding to each file using NCO commands on a Linux system. This example uses a CBOFS fields forecast file listed above:

ncdump -v ocean_time cbofs.t12z.20250306.fields.f011.nc

The output is

ocean_time =

   289695600

This output is seconds since initialization, and each OFS has a different initialization date. To determine the initialization time, follow the second method in the FAQ section “How can I check the output file parameters and their attributes?” For example the initialization date and time for CBOFS is 2016-01-01 00:00:00. To convert this to an UTC datetime, convert ocean_time to a desired time unit (e.g., minutes, hours, or days), if necessary, and then add it to the initialization date. Example code to calculate this using Python is:

 
                        # Get the initialization date and assign it to dt0
                        dt0 = parser.parse(data_set.ocean_time.attrs['units'].replace('seconds since ',''))
                        # Add time (in seconds) to the initialization date to get the time of the model output, and assign it to the data_set’s time field
                        data_set = data_set.assign(
                        ocean_time=[dt0+timedelta(seconds=secs) for secs in data_set.ocean_time.values])
                        

where data_set is the loaded model output netCDF.

Note also that this example is for fields files, which have a single simulation time. Stations files contain nowcast or forecast time series with a 6-minute resolution, so ocean_time is an array with many time entries – all of which need to be converted similarly.

FVCOM-based OFS

To get the simulation time (in UTC) for a fields file from a FVCOM-based OFS, you can run the following command (this example uses a LEOFS fields file):

ncdump - v Times leofs.t06z.20250304.fields.n002.nc

The output is

Times =

"2025-03-04T02:00:00.000000"

Each NetCDF file has a few time-related variables, but the Times variable is the most human-readable (a datetime string) one for FVCOM-based OFS.

Stations files do not contain the Times variable, but rather just the time variable which is an array in ‘seconds since’ format. To calculate the UTC datetime using the time variable, follow the steps similar to the ocean_time variable for ROMS-based OFS: convert time to a desired time unit (e.g., minutes, hours, or days), if necessary, and then add it to the initialization date. The initialization date can be found using the second method in the FAQ section “How can I check the output file parameters and their attributes?” or using a similar approach to the Python code shared above for ROMS fields files.

NOTE: UTC time zone is used for all OFS model outputs.

Each OFS has a set of Technical Reports describing its development and/or the skill assessment results of the hindcast simulation and/or the semi-operational nowcast/forecast runs. Additionally, when available, the Technical Implementation Notices (TINs) or the Service Change Notices (SCNs), issued by the National Weather Service, are included. These can be found in the Model Publications page which also includes documents on general OFS development, skill assessment, implementation, and the operational framework. The last section includes documents on Retired OFS.

The link for the Skill Assessment package on GitHub is: https://github.com/NOAA-CO-OPS/NOS-OFS-Skill-Assessment-Code

The code includes Chesapeake Bay OFS (CBOFS) control files for water levels (wl), currents (cu), water temperature (temp), and salinity (salt) and the results of STEP2, STEP3, STEP6, STEP7, and STEP9 for a currents skill assessment analysis, as an example. On the site, click on the green "Code" box to open a submenu that allows you to download a zip file of the code.

To extract only one variable, i.e., currents for a small subset of the dataset, such as a bay rather than the whole domain for a 3-day period:

1) Go to https://opendap.co-ops.nos.noaa.gov/ofsdataagg/index.html and select the OFS of interest.
2) At the top-left corner of the map, select either of the square or pentagon to use in sub-setting the domain and select the region of interest.
3) In the left-hand menu, select the time period of interest. At this time, the maximum window is 5 days. Therefore, for one month, you would need approximately 6 to 7 submissions to gather all the data of interest.
4) Select “Velocity” as "Data Type" for getting currents data. Other variables available are elevation (water level), temperature, and salinity.
5) In the "Data Profile" window, please choose “3D Full Profile” or “Surface Only” depending on your needs.
6) Input the email address where you would like to receive the data.
7) Click “Submit”.

Note 1: UTC time zone is used for all NOS OFS model outputs.
Note 2: The maximum requested time range allowed is 5 days, and only data from the past 2 years is available
Note 3: You can also use Vertex 1-4 (or more) to manually input the domain you want. This option ensures that the user gets exactly the same domain in the 6 to 7 submissions mentioned in this example.
Note 4: This tool is limited to the most recent two years of NC files only. If you request data older than 2 years, no results will be generated (i.e. the NC file you receive will be 0 kb in size).
Note 5: If the requested end date is within the next 3 days, the forecast files will be aggregated. Otherwise, only nowcast files are aggregated.
Note 6: The aggregation is only for fields or 2ds files; not for station files.

The OFS output is in the form of:

● 2-dimensional (with filename **.2ds.**.nc) and 3-dimensional (with filename **.fields.**.nc) hourly fields; these files are referred to as “fields files”

● 1-dimensional 6-minute data at specific locations, or stations (with filename **.stations.**.nc); these files are referred to as “station files”

For fields files: refer to the FAQ section “How can I aggregate or subset OFS data?” for details on manually aggregating and subsetting fields data from the past 2 years with a maximum window of 5 days.

For station files: The NOAA/NOS/Center for Operational Oceanographic Products and Services (CO-OPS) maintains a network of water level observing stations which display 6-minute water level data in real-time. For locations where OFS output coincides with a realtime observation station (and the nowcast and forecast guidance is available in the station files), the observed and modeled water levels can be downloaded via the CO-OPS API for Data Retrieval.

In addition, refer to the FAQ section “Where can I access the OFS model output archives?” for where to access the native model output for an OFS.

The water level data are displayed relative to the mean lower low water (MLLW) datum. Users can use the variable called "zeta" (use zeta_adj for CREOFS) in OFS output NetCDF files and add the datum value of the variable of "mllwtomsl" in the datum netCDF files.

The vdatum NetCDF for all OFS can be downloaded from: https://noaa-nos-ofs-pds.s3.amazonaws.com/index.html#OFS_Grid_Datum/

For example, for CBOFS: Water levels relative to MLLW = zeta(i,j) + mllwtomsl(i,j)

OFS map and feature services are accessible to the public through the following link: https://mapservices.weather.noaa.gov/static/rest/services/NOS_Observations

To download a file containing the grid boundary of all OFS, click on “NOS Observations/CO_OPS_OFS_Models (Map Server). Under the “View In” section at the top of the page, select the preferred software or file format to download.

Use the nowcast files. For example, for CBOFS, a ROMS-based OFS, the stations nowcast files should be concatenated in the following order:

For example, for CBOFS, a ROMS-based OFS, the fields nowcast files should be aggregated in the following order:

NOTE: Concatenating the example files above (e.g., cbofs.t00z.20250304.stations.nowcast.nc through cbofs.t18z.20250305.stations.nowcast.nc) results in a continuous time series of output data from March 3, 1800 UTC through March 5, 1800 UTC. To create a time series starting at 000 UTC on March 4 rather than beginning at the end of March 3, begin concatenation with the file cbofs.t06z.20250304.stations.nowcast.nc. See FAQ sections “What is the OFS model output file naming convention?” and “What is the difference between the file’s timestamp and the simulation time, and how can I extract simulation time information?” for more information on how the model output file names translate to calendar time.

NOTE: For FVCOM-based OFS:

● the n000 fields nowcast file is a duplicate of the n006 fields file of the previous cycle

● the f000 fields forecast file is a duplicate of the n006 fields file of the same cycle.

ROMS-based OFS do not output the n000 or f000 to avoid these duplications.

Surface wind rotation to true east-north wind from ROMS curvilinear grid can be done by using the following algorithms:

U-east =U_wind * cos(angle) - V_wind * sin(angle)

V-north =U_wind * sin(angle) + V_wind * cos(angle)

where U_wind, V_wind are from ROMS model results and the angle is the angle between X-axis and EAST.

The ROMS Wiki page provides more information on vertical S-coordinates, and the matlab script linked here computes and plots ROMS vertical stretched coordinates.

The Finite-Volume Community Ocean Model (FVCOM), developed by the University of Massachusetts – Dartmouth, is one of the NOAA/National Ocean Services’ (NOS) preferred core ocean models operated under a standardized Coastal Ocean Modeling Framework (COMF-HPC) at NOAA’s Weather and Climate Operational Supercomputing System (WCOSS2) operated by the NOAA/National Weather Service (NWS) National Center for Environment Prediction (NCEP) Central Operations (NCO). A benefit of being implemented at WCOSS2, is that the OFS have direct access to the NWS operational meteorological products that they need to run reliably.

FVCOM-based Operational Forecast System (OFS)	Horizontal Resolution	Number of Vertical Layers	Number of Nodes
Northern Gulf OFS (NGOFS2)	40 m – 14 km	40	303,714
San Francisco Bay OFS (SFBOFS)	12 m – 4 km	20	54,120
Lake Erie OFS (LEOFS)	400 m – 4 km	20	6,106
Lake Michigan Huron OFS (LMHOFS)	50 m – 2.5 km	20	90,806
Lake Superior OFS (LSOFS)	200 m - 2.5 km	21	90,964
Lake Ontario OFS (LOOFS)	200 m - 2.5 km	21	34,395
Salish Sea and Columbia River OFS (SSCOFS)	100 m - 10 km	10	239,734

Model Documentation

All model documentation, including technical reports on the coastal ocean modeling framework, the NOS standards for evaluating operational nowcast and forecast hydrodynamic model systems, and skill assessment (both the software and the results) can be found in the OFS Publications page.

A complete set of archives can be found under the FAQ section “Where can I access the OFS model output files?” The table below lists OFS output file names and the archives in which each type of file can be found.

OFS Output File Name	NOMADS Data at NCEP	CO-OPS THREDDS Data Server
Nowcast stations NetCDF file names: ● OFS.tCCz.YYYYMMDD.stations.nowcast.nc	Most recent 24 hours	Most recent 31 days
Forecast stations NetCDF file names: ● OFS.tCCz.YYYYMMDD.stations.forecast.nc	Most recent 24 hours	Most recent 31 days
Nowcast field/gridded NetCDF file names: ● OFS.tCCz.YYYYMMDD.fields.nHHH.nc     HHH = 000, 003, 006 for NGOFS     HHH = 000-006 for LEOFS, LMHOFS, LOOFS, LSOFS, SFBOFS ● OFS.tCCz.YYYYMMDD.2ds.nHHH.nc     For NGOFS2 only, HHH = 000-006	Most recent 24 hours	Most recent 31 days
Forecast field/gridded NetCDF file names: ● OFS.tCCz.YYYYMMDD.fields.fHHH.nc     HHH = 000, 003, 006, 009,...048 for NGOFS     HHH = 000-048 for SFBOFS     HHH = 000-120 for LEOFS, LMHOFS, LOOFS, LSOFS ● OFS.tCCz.YYYYMMDD.2ds.fHHH.nc     For NGOFS2 only, HHH = 000 - 048	Most recent 24 hours	Most recent 31 days
Nowcast 3-Dimensional Field Output files on a Regular Grid: ● OFS.tCCz.YYYYMMDD.regulargrid.nHHH.nc     HHH = 000, 003, 006 for NGOFS     HHH = 000-006 for LEOFS, LMHOFS, LOOFS, LSOFS, SFBOFS	Most recent 24 hours	Most recent 3 days
Forecast 3-Dimensional Field Output files on a Regular Grid: ● OFS.tCCz.YYYYMMDD.regulargrid.fHHH.nc     HHH = 000, 003, 006, 009,...048 for NGOFS     HHH = 000-048 for SFBOFS     HHH = 000-120 for LEOFS, LMHOFS, LOOFS, LSOFS	Most recent 24 hours	Most recent 3 days

The Regional Ocean Modeling System (ROMS), developed by Rutgers University, is one of the NOAA/National Ocean Services’ (NOS) preferred core ocean models operated under a standardized Coastal Ocean Modeling Framework (COMF-HPC) at NOAA’s Weather and Climate Operational Supercomputing System (WCOSS2) operated by the NOAA/National Weather Service (NWS) National Center for Environment Prediction (NCEP) Central Operations (NCO). A benefit of being implemented at WCOSS2, is that the OFS have direct access to the NWS operational meteorological products that they need to run reliably.

ROMS-based Operational Forecast System (OFS)	Horizontal Resolution	Number of Vertical Layers	Dimensions
Chesapeake Bay OFS (CBOFS)	50 m – 5 km	20	291 X 332
Cook Inlet OFS (CIOFS)	10 m – 3.5 km	30	724 X 1044
Delaware Bay OFS (DBOFS)	100 m – 3 km	10	119 X 732
Gulf of Maine OFS (GoMOFS)	~700 m	30	1173 X 777
Tampa Bay OFS (TBOFS)	100 m – 1.2 km	11	176 X 290
West Coast OFS (WCOFS)	~4 km	40	348 X 1016

Model Documentation

ROMS documentation can be found in the ROMS wiki page, and the ROMS FAQs reference page is located here. All NOS model documentation, including technical reports on the coastal ocean modeling framework, the NOS standards for evaluating operational nowcast and forecast hydrodynamic model systems, and skill assessment (both the software and the results) can be found in the OFS Publications page.

A complete set of archives can be found under the FAQ section “Where can I access the OFS model output files?” The table below lists OFS output file names and the archives in which each type of file can be found.

OFS Output File Name	NOMADS Data at NCEP	CO-OPS THREDDS Data Server
Nowcast stations NetCDF file names: ● OFS.tCCz.YYYYMMDD.stations.nowcast.nc	Most recent 24 hours	Most recent 31 days
Forecast stations NetCDF file names: ● OFS.tCCz.YYYYMMDD.stations.forecast.nc	Most recent 24 hours	Most recent 31 days
Nowcast field/gridded NetCDF file names: ● OFS.tCCz.YYYYMMDD.fields.nHHH.nc     HHH = 001-006 for CBOFS, CIOFS, DBOFS, TBOFS     HHH = 003, 006 for GoMOFS     HHH = 003, 006, 009, 012,...024 for WCOFS ● OFS.tCCz.YYYYMMDD.2ds.nHHH.nc     For GoMOFS only, HHH = 001-006     For WCOFS only, HHH = 001-024	Most recent 24 hours	Most recent 31 days
Forecast field/gridded NetCDF file names: ● OFS.tCCz.YYYYMMDD.fields.fHHH.nc     HHH = 001-048 for CBOFS, CIOFS, DBOFS, TBOFS     HHH = 003, 006, 009, 012,...072 for GoMOFS and WCOFS ● OFS.tCCz.YYYYMMDD.2ds.fHHH.nc     For GoMOFS and WCOFS only, HHH = 001 - 072	Most recent 24 hours	Most recent 31 days
Nowcast 3-Dimensional Field Output files on a Regular Grid: ● OFS.tCCz.YYYYMMDD.regulargrid.nHHH.nc     HHH = 001-006 for CBOFS, CIOFS, DBOFS, TBOFS     HHH = 003, 006 for GoMOFS     HHH = 003, 006, 009, 012,...024 for WCOFS	Most recent 24 hours	Most recent 3 days
Forecast 3-Dimensional Field Output files on a Regular Grid: ● OFS.tCCz.YYYYMMDD.regulargrid.fHHH.nc     HHH = 001-048 for CBOFS, CIOFS, DBOFS, TBOFS     HHH = 003, 006, 009, 012,...072 for GoMOFS and WCOFS	Most recent 24 hours	Most recent 3 days