NOUS41 KWBC 141450 AAC
Technical Implementation Notice 15-36, Amended
National Weather Service Headquarters Silver Spring MD
1050 AM EDT Thu Sep 14 2017
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
Other NWS Partners, Users and Employees
From: Dave Myrick
NWS Office of Science and Technology Integration
Subject: Amended: Upgrade to Global-Real Time Ocean Forecast
System (RTOFS): Effective October 17, 2017
Updated to change the implementation date from to be determined
to October 17, 2017, and include more details on the output
timing changes in the second to last paragraph before contacts.
Effective October 17, 2017, beginning with the 0000 Coordinated
Universal Time (UTC) run, NCEP will upgrade the Global-RTOFS.
The system changes include:
- An increase in the number of vertical layers from 32 to 41
hybrid layers with additional iso-level coordinate layers in the
- The coupling of the ocean component Hybrid Coordinate Ocean
Model (HYCOM) to Los Alamos National Laboratory's Community Sea
Ice (CICE) model using v4.0 of Earth System Modeling Framework
- Updated bathymetry, which improves representation of grid
points in shallow regions where minimum depth is set to 5m.
- An update of the climatology from the U.S. Navy's Generalized
Digital Environmental Model (GDEM) v3.0 to v4.2.
- An equation of state, which is updated from 9 terms to 17
Benefits of the system changes include:
- Fine vertical resolution in the oceanic mixed layer with 9
additional near surface layers.
- Anticipated improvement to air-sea boundary flux for future
coupled applications (including hurricanes).
- Improved vertical coastal ocean resolution for downstream
applications, such as the National Ocean Service Operational
Forecast System (NOS-OFS) and Eco forecasting.
- Planned addition of Sea Ice products.
- The following NetCDF files will be made available on the NCEP
Sea Surface Temperature (SST) and Surface current components U,
V time series for the last day of nowcast/hindcast
SST and Surface current components U, V time series where "#"
equals day 4 or 5 of forecast
SST and Surface current components U, V time series for days 1-3
Where "????" is either "prog" (Prognostic) or "diag"
Where "X" is either "f" (Forecast) or "n" (Nowcast)
- The following surface files will now be available on the NCEP
Where FFF is either hourly "f00"-"f192" or "n00" or hourly "n-
- The following ice files will now be available on the NCEP
Where ??? is either "anal" or "fcst1" or "fcst2"
Details on the contents of these files are available at:
- The high vertical resolution (hvr) regional NetCDF files will
be renamed on the NCEP server. The file name changes reflect
more descriptive region names. The file name changes are as
Where "HHH" is from 000-048
Where "HHH" is from 001-192
- The current 3d archive files will now be available every 6
hours for both forecast and nowcast and the "a" files will
rtofs_glo.t00z.*.archv.a -> rtofs_glo.t00z.*archv.a.tgz
A consistent parallel feed of data will be made available on the
NCEP HTTP server once the model is running in parallel on the
NCEP Weather and Climate Operational Supercomputing System
(WCOSS) on or around September 15, 2017. The data will be
available at the following URL:
No changes are expected to products over NOAAPORT. Users can
find the data via the NCEP ftp and HTTP servers at:
Users can find additional information about the RTOFS at the
following Environmental Modeling Center website:
The original design of the Global RTOFS was that the model would
run throughout the day with all products being available by 00
UTC the following day. With any upgrade, it is possible that
delivery times during the day may change either earlier or
later, but the final products will still always be available by
00 UTC the following day.
With this upgrade certain analysis products will be available
earlier, and certain forecast and analysis products will be
available between 20 and 90 minutes later than current
production. This change in timing will impact the NCEP Web
Services as well as NOAAPORT/SBN. NCEP is also removing the
contingency that could have caused the last 2 days of the
forecast to be canceled due to resource constraints. This means
that no part of the Global RTOFS will be pre-emptively canceled.
NCEP encourages all users to ensure their decoders are flexible
and are able to adequately handle changes in content order,
changes in the scaling factor component within the product
definition section (PDS) of the GRIB files, and also any volume
changes which may be forthcoming. These elements may change with
future NCEP model implementations. NCEP will make every attempt
to alert users to these changes prior to any implementations.
For questions regarding the changes to this model, such as
timing, please contact:
College Park, Maryland
For questions regarding the dataflow aspects of these data sets,
NCEP/Dataflow Team Lead
College Park, Maryland
NWS Technical Implementation Notices are online at: