NOUS41 KWBC 041535 AAA



Service Change Notice 17-125 Updated

NOAA’s National Ocean Service Headquarters Silver Spring MD

1135 APM EST Thu Jan 4 2018


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: Updating National Ocean Service's

         Oceanographic Forecast Modeling Systems

         Effective Jan 10, 2018


Updated to change the implementation date from January 3, 2018

to January 10, 2018


Effective January 10, 2018 beginning at 15z Coordinated

Universal Time (UTC), updates of National Ocean Service

Operational Forecast Systems 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-OPS). The updates include Regional Ocean Modeling System

(ROMS) and Finite Volume Community Ocean Model(FVCOM) code

version updates and updates to the Coastal Ocean Modeling

Framework (COMF) shared by all NOS operational forecast systems.

COMF updates include using NCO standard module files and other

enhancements. The details of this implementation are:


1. ROMS version updates for the Operational Forecast Systems of

the Chesapeake Bay (CBOFS), the Delaware Bay (DBOFS), and the

Tampa Bay (TBOFS)


The core ocean model currently used for CBOFS, DBOFS and TBOFS

is ROMS3.6 v90 released in 2007, which is no longer supported by

the ROMS community. The latest ROMS3.7 version 859 released in

August 2017 will replace the ROMS Version 90. The latest ROMS3.7

version 859 fixes many code bugs that exist in ROMS Version 90,

and adds many new features. This new version also added new

biological modules for Chesapeake Bay hypoxia forecasting and

Gulf of Maine harmful algal bloom (HAB) forecasting. This

version also inplements a new option of C-preprocessor (CPP) in

the surface heat flux boundary condition subroutine (set_vbc.F)

to prevent the water temperature from decreasing beyond the

freezing point of seawater (when a sea ice model is not active).

There are no major changes regarding hydrodynamics and physics

in the latest ROMS3.7 Version 859 compared with ROMS3.6 Version

90. Therefore, the results obtained from ROMS3.6 and ROMS3.7 are

very similar for CBOFS, DBOFS and TBOFS, and there are no

significant changes to CBOFS, DBOFS and TBOFS products (e.g.,

file name, contents, etc.) for the end users.  


2. FVCOM version updates for the Operational Forecast Systems of

the Northern Gulf of Mexico (NGOFS), the nested Northeastern

Gulf of Mexico (NEGOFS), the nested Northwestern Gulf of Mexico

(NWGOFS), and the San Francisco Bay (SFBOFS)


This new version will resolve and enhance the following


- Fixed the jetty bug in the present FVCOM version used by

NWGOFS (vertvl_edge.F). This bug caused modeled water

temperature near jetties to be unrealistically cold.

- Added a new module to calculate heat flux for Great Lakes OFS


- Added a new routine to prevent the water temperature from

decreasing beyond the freezing point of water (when an ice model

is not active)


3. Delivery Time is delayed about 5 minutes


In order to improve numerical instability during extreme weather

events, such as Hurricane Harvey and Irma, the integration time

step was decreased by half for CBOFS, DBOFS, TBOFS, NGOFS,

NEGOFS and NWGOFS. As a result, dissemination of their products

will be delayed about 5 minutes on the NCEP NOMADS and FTP



4. Changes in input and output files for CBOFS, DBOFS, and TBOFS


- Changed double precision to single precision for variables of

water levels, currents, water temperature and salinity in model

output NetCDF files to reduce output file size and improve data

dissemination performance for CBOFS, DBOFS, and TBOFS.


- 4 km nested NAM products replace 12 km NAM products to

generate meteorological forcing conditions for CBOFS, DBOFS, and



- Files being removed from NCEP Web Services referenced below:

  nos.{c,d,t} (f000 only)

  nos.{c,d,t} (n000 only)


 CC is cycle (03,09,15,21)

Where YYYYMMDD is year, month and day; CC is cycle


All hot restart files of nos.{OFS}.rst.nowcast.YYYYMMDD.tCCz.*

were removed because they are duplicate with



Gridded and station/point forecast guidance for NOS models will

be available in netCDF format on CO-OPS THREDDS server


and on NCEP Web Services:



Graphics products are displayed on the CO-OPS web page at



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 prior to implementation




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: