NOUS41 KWBC 041700 AAA



Service Change Notice 17-108 Updated

National Ocean Service Headquarters Silver Spring MD

Related by National Weather Service Silver Spring MD

100 PM EST Mon Dec 4 2017


To:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS and NOS partners and NWS and NOS employees


From:     Patrick Burke

          Chief, Oceanographic Division

          NOS/Center for Operational Oceanographic Products

          and Services


Subject:  Updated: Implementation of new Oceanographic Forecast

          Modeling System for the Gulf of Maine

          Effective January 3, 2018


Updated to change the implementation date from Dec 19, 2017 to

Jan 3, 2018 and to include major changes to the details related

to the upgrade. Users are urged to read through this entire



Effective January 3, 2018 beginning at 18z Coordinated Universal

Time (UTC), the NOAA/National Ocean Service (NOS) Gulf of Maine

Operational Forecast System (GoMOFS) will be implemented on

NOAA’s Weather Climate Operational Supercomputing System (WCOSS)

operated by NCEP Central Operations (NCO) and maintained by the

Center for Operational Oceanographic Products and Services (CO-



1) GoMOFS System


GoMOFS will provide users with nowcasts (analyses of near

present) and forecast guidance of the three-dimensional physical

conditions of the Gulf of Maine, including surface water levels

and 3-D water currents, water temperature, and salinity out to

72 hours.


As its core ocean prediction model, GoMOFS uses the Regional

Ocean Modeling System (ROMS) developed by the ocean modeling

community and supported by Rutgers University.  ROMS is a free-

surface, terrain-following, primitive equations ocean model

widely used by the scientific and operational community for a

diverse range of applications. GoMOFS operates within the NOS

Coastal Ocean Modeling Framework (COMF) and has four daily

nowcast and forecast cycles at 00, 06, 12, and 18 UTC.


The GoMOFS orthogonal grid has 1173 x 777 horizontal grid points

with roughly 700m horizontal resolution. The vertical grid

follows the terrain and consists of 30 model levels. The grid

bathymetry of the Gulf of Maine ranges from 3m near the coast to

4,500m along its southern open boundary.


The surface meteorological forcing used to run GoMOFS is based

on forecast guidance from the National Weather Service (NWS)

North American Mesoscale (NAM) weather prediction model (for

both nowcast and forecast). Forecast guidance from the NCEP

Global Forecast System (GFS) are used as a backup forcing if

forecast guidance from the NAM is not available.


GoMOFS relies on NCEP’s Global Real-Time Ocean Forecast System

(G-RTOFS) to provide open boundary temperature, salinity and

sub-tidal water level. The ADCIRC 2001 Tidal Database is used to

generate GoMOFS tidal forcing. Additionally, near real-time

observations from USGS river gauges are used to specify river

discharge, river temperature and salinity at seven major rivers

observations at seven major rivers in the Gulf of Maine.


2) GoMOFS Product Output


Fields and station forecast guidance from GoMOFS will be

available in netCDF format on CO-OPS THREDDS server


and on NCEP Web services under gomofs.YYYYMMDD

Where YYYYMMDD is year, month, and day


GoMOFS is currently displayed in developmental mode here:


After it is transitioned to production, it will be displayed at:


GoMOFS has two types of model output data. Where YYYYMMDD is

year, month, day; CC is cycle (00, 06, 12, 18)


- One is field/gridded data which include three-dimensional

gridded data with 3 hour interval and two-dimensional gridded

surface data with one hour interval.

  HHH is 003 and 006

  HHH is 003, 006, ...,072

for surface layer field NetCDF file,

  HHH is 001-006

  HHH is 001, 002, 003, ..., 072


- Flag log file for generating flags for Continuous Operational

Real-Time Monitoring System (CORMS)



- Initial files for nowcast:


- ROMS runtime log file:





- The other is station/point output data with 6 minutes

interval. Water lever, surface wind, water temperature, water

salinity and currents are the preliminary output variables.


3) Model input files


Surface meteorological forcing NetCDF file,

River forcing file:

Open boundary forcing file:

Tidal open boundary forcing file:

ROMS runtime input file:


Climatological nudging file:



GoMOFS predictions are used by commercial, recreational

mariners, fisherman, emergency managers, search and rescue

responders, and NWS marine weather forecasters. The development

and implementation of GoMOFS is a joint project between the

NOS/Office of Coast Survey (OCS), the NOS/Center for Operational

Oceanographic Products and Services (CO-OPS), and NWS/NCEP/NCO. 

Rutgers University provided technical support for ROMS.  GoMOFS

is monitored 24 x 7 by both NCO/NCEP and CO-OPS Continuous Real-

Time Monitoring System (CORMS) personnel.


NCEP urges all users to ensure their decoders can handle changes

in content order and volume changes. These elements may change

with future NCEP model implementations. NCEP will make every

attempt to alert users to these changes before implementation.


As part of NCEP’s standard 30 day parallel testing, the new

output products will be available here:


Any questions, comments or requests regarding this

implementation should be directed to the contacts below.  We

will review any feedback and decide whether to proceed.


If you have any questions concerning these changes, please


Dr. Aijun Zhang

NOS/Center for Operational Oceanographic Products and Services

Silver Spring, MD



For questions regarding the dataflow aspects, please contact:

Carissa Klemmer

NCEP/NCO Dataflow Team Lead

College Park, MD



NWS National Service Change Notices are online at: