NOUS41 KWBC 171810

PNSWSH

 

Public Information Statement 16-04

National Weather Service Headquarters Washington DC

210 PM EST Wed Feb 17 2016

 

To:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network

          -NOAAPORT

          Other NWS Partners, Users and Employees

 

From:     Timothy McClung

          Portfolio Manager

          Office of Science and Technology Integration

 

Subject:  Soliciting public comments on the removal of legacy

          Global Forecast System (GFS) gridded output through

          March 25, 2016

 

The National Centers for Environmental Prediction (NCEP) is

seeking comments through March 25, 2016, on removing some legacy

gridded products from the GFS. These products would no longer be

disseminating via NOAAPORT and the NWS ftp server.

 

The operational GFS model currently runs on a T1534 (~13 km

resolution) Semi-Lagrangian grid. Output is made available from

the GFS on grids ranging in resolution from 2.5km up to 5

degrees latitude/longitude. Many of these legacy low-resolution

grids are available for limited forecast hours and fields and

are not produced for all cycles of the GFS. The same information

is provided on expanded grids with finer-resolution and more

variables. Removing these legacy products is crucial to free up

compute and network resources for newer products to be

distributed. If approved, NCEP would remove the following

products:

 

-NOAAPORT GFS gridded output

-Web services WAFS GRIB1 output

-NOAAPORT Vessel Sea Ice and Fog gridded output

 

In 2014, the NWS did an analysis to determine the optimal set of

output grids from the GFS to meet the needs of NWS forecasters. 

From this analysis, the regional 20 km grids and global 1 degree

were added to NOAAPORT in March 2015.

 

http://www.nws.noaa.gov/os/notification/tin14-54gfs_noaaport.htm

 

Any one of these new grids will serve as a replacement to the

proposed discontinued grids, covering more area and containing

additional variables alongside the legacy ones.

 

Table 1: Gridded GFS products on NOAAPORT for proposed removal

 

Grid   Res       Area             Map Projection

-----------------------------------------------------------

#160   47 km     Alaska           North Polar Stereographic

#161   0.5 deg   Puerto Rico      Latitude/Longitude

#211   80 km     CONUS            Lambert Conformal

#212   40 km     Regional CONUS   Lambert Conformal

#213   95 km     Alaska           Polar Stereographic

#225   80 km     Hawaii           Mercator

#254   40 km     Pacific Region   Mercator

 

Please see the link below for a graphical representation of the

old grids and the new grids. 

 

http://www.nco.ncep.noaa.gov/pmb/changes/gfs_AWIPS_grids.pdf

 

WMO headers for these grids slated for removal are listed at:

 

http://www.nco.ncep.noaa.gov/pmb/changes/gfs_AWIPS_grids.shtml

 

Table 2: GRIB1 files on NWS web servers for proposed removal

 

weather.noaa.gov/pub/SL.us008001/ST.opnl/MT.gfs_CY.CYCLE/RD.YYYY

MMDD/PT.grid_DF.gr1/

ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/MT.gfs_CY.CYCLE/RD.

YYYYMMDD/PT.grid_DF.gr1/

  where CYCLE is 00, 06, 12, 18

  where YYYYMMDD is Year, Month, Day

  where FFF is forecast hour from 000-120

 

Grid     Res       Area  File Name        

-----------------------------------------------------------  

#37-44   1.25 deg  WAFS  fh.FFF_tl.press_ar.octant[ijklmnop]

 

Replacement GRIB2 output is available today with the same naming

convention under this path:

ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/MT.gfs_CY.CYCLE/RD.

YYYYMMDD/PT.grid_DF.gr2/

 

3) Table 3: GRIB1 files on the NCEP web servers for proposed

removal

http://nomads.ncep.noaa.gov/pub/data/nccf/pcom/gfs/

ftp://ftp.ncep.noaa.gov/pub/data/nccf/pcom/gfs/

  where CC is cycle 00, 06, 12, 18

  where YYYYMMDD is Year, Month, Day

  where FF is forecast hour from 00-72

 

Grid     Res       Area  File name        

-----------------------------------------------------------

#37-44   1.25 deg  WAFS  xtrn.wfsgfsCCFF.gfs_wafs_fFF_CC

#37-44   1.25 deg  WAFS  xtrn.wfsgfsCCFFa.gfs_wafs_fFF_CC

#37-44   1.25 deg  WAFS  xtrn.wfsgfsCCFFb.gfs_wafs_fFF_CC

 

WAFS replacement GRIB2 output is available today with all of the

same variables, plus a few additional as well as extended

forecast hours.

 

http://www.nco.ncep.noaa.gov/pmb/changes/gfs_wafs_vars.txt

 

The same grid output can be found here:

ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/MT.gfs_CY.CC/RD.YYY

YMMDD/PT.grid_DF.gr2/

With names like fh.FFF_tl.press_ar.octant[ijklmnop]

  where [ijklmnop] equate to grids [37,38,39,40,41,44,43,44]

 

Table 4: Vessel Sea Ice (ice growth rate) and Fog (visibility)

GRIB2 products on NOAAPORT for proposed removal

 

Grid   Res       Area             Map Projection

-----------------------------------------------------------  

#232   1 deg     Northern Hem     latitude/longitude

 

There are no known users of either of these gridded outputs,

therefore we have no replacement products.

 

WMO headers for these grids slated for removal are listed at:

 

http://www.nco.ncep.noaa.gov/pmb/changes/omb_AWIPS_grids.shtml

 

The NWS will evaluate all comments to determine whether to

proceed with these changes. If approved, a TIN will be issued

giving 30 days notice of the implementation date.

 

Send comments on this proposal to:

 

     Carissa Klemmer

     NWS/NCEP Central Operations

     Dataflow Team Lead

     College Park, MD

     carissa.l.klemmer@noaa.gov

 

NWS National Public Information Statements are online at:

 

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

 

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