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PNSWSH

 

Technical Implementation Notice 16-08 Amended

NOAA’s National Ocean Service Headquarters Washington DC

Related by National Weather Service Washington DC

225 PM EDT Tue Apr 19 2016

 

To:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network

          -NOAAPORT

          Other NWS and NOS partners and NWS and NOS employees

 

From:     Timothy McClung

          Portfolio Manager

          Office of Science and Technology Integration

 

Subject:  Amended: Upgrading National Ocean Service’s Lake Erie

          Operational Forecast System, Effective May 3, 2016

 

Amended to change the date to May 3, 2016

 

Effective on or about May 3, 2016 beginning at 12z Coordinated

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

Prediction (NCEP) will be upgrading the National Ocean Service’s

Lake Erie Operational Forecast System (LEOFS). The summary of

this upgrade are:

  - Change the core numerical model

  - Change the model setup

  - Change the run schedule

  - Change the output filenames

  - More stations/points in the station output

 

1. Core numerical model changes from POM to FVCOM

 

The core ocean model used for the present LEOFS is a customized

version of the Princeton Ocean Model (POM), which is not a

standard hydrodynamic model for NOS OFS. The upgraded LEOFS uses

Finite Volume Community Ocean Model (FVCOM), one of standard

core hydrodynamic models for NOS OFS development and

implementation. FVCOM is a widely used, open-source, community

supported model. The upgrade of LEOFS is a collaborative effort

of NOAA’s Great Lakes Environmental Laboratory, NOS/Coast Survey

Development Laboratory, NOS/Center for Operational Products and

Services, and NWS/NCEP Central Operations. 

 

The present LEOFS uses a 81 x 24 regular horizontal grid with

5km resolution and 10 vertical layers while the upgraded LEOFS

uses an unstructured triangular grid of 6106 nodes and 11509

elements with grid size ranging from 400m to 3.5km and 20

vertical layers. 

 

2. Model setup Changes

 

The nowcast cycles of the present LEOFS are forced by surface

meteorological analyses based on surface weather observations

from land stations and overwater platforms  while the forecast

cycles are forced by surface weather forecasts from the National

Weather Service’s National Digital Forecast Database (5-km

spatial resolution).The nowcast cycles of the upgraded LEOFS is

forced by the 2-hr forecast guidance from the NWS’ High

Resolution Rapid Refresh (HRRR) model while the forecast cycles

are forced by forecasts from the NDFD (2.5km spatial

resolution).     

 

The present LEOFS has no lateral boundary conditions. The

upgraded LEOFS has two open boundaries: one for the Detroit

River and one for the Niagara River. For the nowcast cycle,

near-real-time water level observations from nearby NOAA water

level gauges at Gibraltar, MI and Buffalo, NY are used to

specify water level open boundary conditions, respectively. An

offset for each open boundary is applied to the observed water

level to account for the rough river channel representation

and/or distance between station and boundary location. The

offset is adjusted each cycle based on the model observation

discrepancy at Fermi Power Plant, MI and Buffalo, NY,

respectively. Water temperature observations from the USGS

station at Fort Wayne, MI are used to specify temperature along

the open boundaries. For the forecast cycle, the open boundary

conditions are persisted from nowcast cycle for both water

levels and water temperature.

 

3. Cycle Changes

 

 -Current:

    The nowcast runs every hour, and forecast runs every 6-hour

at 00, 06, 12, 18z for 60-hour forecast.

 -Upgraded:

    Both nowcast and forecast will run every 6 hours at 01, 07,

13 and 19z, and forecast runs for 120-hour. This is to be

consistent with other OFS run schedules.

 

4. Model Output Change

 

The model output files available on NCEPs http and ftp servers

  nomads.ncep.noaa.gov/pub/data/nccf/com/nos/prod/

  ftpprd.ncep.noaa.gov/data/nccf/com/nos/prod

  ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nos/prod

 

- The LEOFS files will change in directory structure from:

  /glofs.YYYMMDD -> /leofs.YYYYMMDD/

Where YYYYMMDD is Year, Month, Day

 

- The upgraded LEOFS will follow NOS OFS standard file name

convention. Only the first octet will change from:

  glofs.leofs.*.YYYYMMDD.tCCz.nc ->

  nos.leofs.*.YYYYMMDD.tCCz.nc

Where CC is cycle time

 

- The field output is now hourly, so each file contains only one

time record.

  glofs.leofs.fields.forecast.YYYYMMDD.tCCz.nc ->

  nos.leofs.fields.fFFF.YYYYMMDD.tCCz.nc

  glofs.leofs.fields.nowcast.YYYYMMDD.tCCz.nc ->

  nos.leofs.fields.nNNN.YYYYMMDD.tCCz.nc

Where FFF is from 000 to 120

Where NNN is from 000 to 006

 

- The restart files will be changing both in name and format.

This will more accurately follow the NOS OFS standards:

  glofs.leofs.rst.nowcast.YYYYMMDD.tCCz.bin ->

  nos.leofs.rst.nowcast.YYYYMMDD.tCCz.nc

 

- Point/station Output Changes

The file now contains a total of 28 stations. In addition to the

11 stations in the present LEOFS, 4 more buoy locations (Oregon,

OH (45165), 2 near Cleveland, OH (45164 and 45169), Erie, PA

(45167)), 6 water level stations on the Canadian coast (Bar

Point, Kingsville, Erieau, Port Stanley, Port Dover and Port

Colborne), 5 points for NERFC potential model use and 2 points

on the open boundary are also included. 

 

Gridded and point forecast guidance from parallel runs will be

available in netCDF files on the NCEP NOMADS server in the

directory,

  para.nomads.ncep.noaa.gov/pub/data/nccf/com/nos/para/

 

Graphics products are now displayed on the CO-OPS developmental

web page at

  http://tidesandcurrents.noaa.gov/ofs/dev/leofs/leofs.html

 

Operational data are also available on CO-OPS thredds server

  http://opendap.co-ops.nos.noaa.gov/thredds/catalog.html

 

If you have any questions concerning these changes, please contact:

Dr. Aijun Zhang

NOS/CO-OPS

Silver Spring, MD

Email: Aijun.Zhang@noaa.gov

 

For questions regarding the data flow aspects, please contact:

Carissa Klemmer

NCEP/NCO Dataflow Team

College Park, MD

Email: ncep.list.pmb-dataflow@noaa.gov

 

NWS National Technical Implementation Notices are online at:

 

http://www.nws.noaa.gov/os/notif.htm

 

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