NOUS41 KWBC 301820 AAA



Service Change Notice 17-34 Updated

National Weather Service Headquarters Silver Spring, MD

220 PM EDT Thu Mar 30 2017


To:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners and Employees


From:     Dave Myrick

          NWS Office of Science and Technology Integration


Subject:  Update: Extratropical Surge and Tide Operational

          Forecast System for the Atlantic and Gulf Coasts

          (ESTOFS Atlantic) Update: Effective April 25, 2017


Updated to include timeliness changes to NOAAPORT and Web



Effective April 25, 2017, beginning with 1200 Coordinated

Universal Time (UTC) run, the National Centers for Environmental

Prediction (NCEP) will upgrade the Extratropical Surge and Tide

Operational Forecast System (ESTOFS) as follows:


   - Increase grid resolution

   - Update open ocean boundary forcing

   - Change GFS components

   - Add Standard Hydrologic Exchange Format (SHEF) output

   - Make changes to directory on NCEP web services

   - Add timeliness delays for all output


1) Output changes


With this upgrade, the following changes will be noted on the

NCEP web services:


Directory Changes:

from - estofs/prod/estofs.YYYYMMDD

to   - estofs/prod/estofs_atl.YYYYMMDD

  Where YYYYMMDD is year, month and day.


Resolution changes:

The increased unstructured grid consists of 1.8 million nodes,

which increases coastal grid resolution from 3 km to 200 m and

extends inland to approximately the 10 m topographic contour

relative to the North American Vertical Datum of 1988 (NAVD88).

The increased resolution will impact the following file:


Addition of SHEF output:

Additional SHEF E format output at each CO-OPS observation

station will be made available. SHEF files contains 30-minute

combined water level (surges with tides), harmonic tidal

prediction (astronomical tides), and sub-tidal water levels (the

isolated surges). The files will be named:





Timeliness changes:

All netcdf files will be delayed up to 10 minutes from current

production output times. All GRIB2 files will be delayed up to

20 minutes from current production output times. 


2) Update open ocean boundary forcing

Update open ocean boundary from TPXO7.2 to TPXO8-ATLAS. Harmonic

tidal constituents from the global tidal model TPXO8-ATLAS are

used to specify tidal water surface fluctuations at the open

ocean boundary, while tidal potential forcing is applied within

the interior of the domain. The performance of this grid for

astronomical tides was verified using published harmonic

constants from National Ocean Service/Center for Operational

Oceanographic Products and Services observation stations located

throughout the domain.


3) GFS grid resolution from 55 km to 13 km

With this upgrade the ESTOFS Atlantic will begin using the

increased Semi-Lagrangian T1534 (~13 km) GFS horizontal

resolution from Lat/Lon 0.5 deg (~55 km).



MDL will deliver output on the website at the observation

stations that provide ETSS predictions:


The Ocean Prediction Center of NWS will deliver graphics of the

model outputs on the following site:


There are no changes to any NOAAPORT/SBN products with this

upgrade. There are, however, timeliness changes up to 15 minutes

later to data distributed over NOAAPORT.


A consistent parallel feed of data is available on the NCEP HTTP

site at the following URL:


NCEP urges all users to ensure their decoders can handle changes

in content order, changes in the scaling factor component within

the product definition section (PDS) of the GRIB files, 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.


Any questions, comments or requests regarding this

implementation should be directed to the contacts below.


For questions concerning science changes, please contact:


Dr. Edward P. Myers

Coastal Marine Modeling Branch

Coast Survey Development Laboratory

NOAA/NOS/Office of Coast Survey

Silver Spring, MD


For questions regarding the data aspects, please contact:


Carissa Klemmer

NCEP/NCO Dataflow Team Lead

College Park, MD


National Service Change Notices are online at: