NOUS41 KWBC 061735

PNSWSH

 

Service Change Notice 18-16

National Weather Service Headquarters Silver Spring, MD

140 PM EST Tue Feb 6 2018

 

To:       Subscribers:

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network

          -NOAAPort

          -Other NWS Partners, Users and Employees

 

From:     Dave Myrick

          NWS Office of Science and Technology Integration

 

Subject:  Upgrade of National Water Model

          Effective March 6, 2018

 

Effective on or about March 6, 2018, beginning with the 1200

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

Environmental Prediction (NCEP) will begin operationally running

Version 1.2 of the National Water Model (NWM).

 

The NWM is an hourly cycling uncoupled analysis and forecast

system that provides streamflow for 2.7 million river reaches

and other hydrologic information on 1km and 250m grids. The

model provides complementary hydrologic guidance at current NWS

River Forecast Center river forecast locations and significantly

expanded guidance coverage and type in underserved locations.

 

The NWM ingests forcing from a variety of sources including

Multi-Radar Multi-Sensor (MRMS) radar-gauge observed

precipitation data and High-Resolution Rapid Refresh (HRRR),

Rapid Refresh (RAP), Global Forecast System (GFS) and Climate

Forecast System (CFS) Numerical Weather Prediction (NWP)

forecast data. USGS real-time streamflow observations are

assimilated and all NWM configurations benefit from the

inclusion of ~1,500 reservoirs. The core of the NWM system is

the National Center for Atmospheric Research (NCAR)-supported

community Weather Research and Forecasting (WRF)-Hydro

hydrologic model. WRF-Hydro is configured to use the Noah Multi-

Parameterization (Noah-MP) Land Surface Model (LSM) to simulate

land surface processes. Separate water routing modules perform

diffusive wave surface routing and saturated subsurface flow

routing on a 250m grid, and Muskingum-Cunge channel routing down

NHDPlusV2 stream reaches. River analyses and forecasts are

provided across a domain encompassing the continental U.S. and

hydrologically-contributing areas, while land surface output is

available on a larger domain that extends beyond the continental

U.S. into Canada and Mexico (roughly from latitude 19N to 58N).

In addition, NWM forcing datasets are provided on this domain at

a resolution of 1km.

 

List of Enhancements in Version 1.2:

 

- Refined land surface and hydrologic parameters by expanding

calibration from ~40 to ~1000+ calibration basins and improving

parameter regionalization process

 

- Improved streamflow data assimilation in Analysis cycle

 

- Introduced the ability to make on-demand updates of

hydrological parameters within the modeling system. Users can

find notifications for when an update was introduced here:

  http://water.noaa.gov

 

- Made various hydrofabric improvements including

   -Fixing 500 stream breaks

   -Adding 12,468 OCONUS basins (94,824 km^2)

   -Adding 680 USGS stream gauges into assimilation routine

   -Adding 328 reservoirs (now totaling ~1,500)

   -Including a new elevation base harmonized with the NHDPlus

channel network

 

- Changes to the fields and metadata contained within NWM output

files including:

   -Compressing the reservoir output files from the Analysis,

Short-, Medium- and Long-Range configurations to match

compression applied to other model output file types. This

compression greatly reduces reservoir-type output file sizes.

Files affected include:

  nwm.tCCz.analysis_assim.reservoir.tm##.conus.nc

Where CC is cycle (00-23) and ## is 00-02.

  nwm.tCCz.short_range.reservoir.f###.conus.nc

Where CC is cycle (00-23) and ### is 001-018

  nwm.tCCz.medium_range.reservoir.f###.conus.nc

Where CC is cycle (00,06,12,18) and ### is 003-240

  nwm.tCCz.long_range.reservoir_M.f###.conus.nc

Where CC is cycle (00,06,12,18), M is member (1-4) and ### is

006-720

   -Changed the data type of the output variable "inflow" from

"float" to "integer" in the reservoir model output files from

the Analysis, Short-, Medium- and Long-Range configurations as

part of compression. Files affected include:

  nwm.tCCz.analysis_assim.reservoir.tm##.conus.nc

Where CC is cycle (00-23) and ## is 00-02.

  nwm.tCCz.short_range.reservoir.f###.conus.nc

Where CC is cycle (00-23) and ### is 001-018

  nwm.tCCz.medium_range.reservoir.f###.conus.nc

Where CC is cycle (00,06,12,18) and ### is 003-240

  nwm.tCCz.long_range.reservoir_M.f###.conus.nc

Where CC is cycle (00,06,12,18), M is member (1-4) and ### is

006-720

   -Changed the data type of the metadata variable "time" from

"double" to "integer" in the forcing output files to match the

convention used in the non-forcing (i.e., model) output files.

Files affected include:

  nwm.tCCz.analysis_assim.forcing.tm##.conus.nc

Where CC is cycle and ## is 00-02

  nwm.tCCz.short_range.forcing.f###.conus.nc

Where CC is cycle and ### is 001-018

  nwm.t${cyc}z.medium_range.forcing.f###.conus.nc

Where CC is cycle and ### is 001-240

   -Addition of output variable (velocity) to the Long-Range

channel output files. Files affected include:

  nwm.tCCz.long_range.channel_rt_M.f###.conus.nc

Where CC is cycle (00,06,12,18), M is member (1-4) and ### is

006-720

   -Additing three output variables (QSfcLatRunoff, QBucket,

QBtmVertRunoff) to the Short-Range and Analysis channel output

files to support channel-only configuration of NWM used in

research and development activities. Files affected include:

  nwm.tCCz.analysis_assim.channel_rt.tm##.conus.nc

Where CC is cycle (00-23) and ## is 00-02.

  nwm.tCCz.short_range.channel_rt.f###.conus.nc

Where CC is cycle (00-23) and ### is 001-018

   -Removal of variable (qlat) from the Analysis, Short-,

Medium- and Long-Range channel output files. Files affected

include:

  nwm.tCCz.analysis_assim.channel_rt.tm##.conus.nc

Where CC is cycle (00-23) and ## is 00-02.

  nwm.tCCz.short_range.channel_rt.f###.conus.nc

Where CC is cycle (00-23) and ### is 001-018

  nwm.tCCz.medium_range.channel_rt.f###.conus.nc

Where CC is cycle (00,06,12,18) and ### is 003-240

  nwm.tCCz.long_range.channel_rt_M.f###.conus.nc

Where CC is cycle (00,06,12,18), M is member (1-4) and ### is

006-720

   - Network Common Data Form (NetCDF) metadata and data

structure updates to improve compatibility with NetCDF file

readers--as above, decoders may need to be adjusted to adapt to

these changes.

 

General Framework:

 

Version 1.2 of the NWM will be run in the same four

configurations as Version 1.1--Analysis and Assimilation, Short-

Range, Medium-Range and Long-Range.

 

End users are able to view the output via the interactive map

and image viewer on the Office of Water Prediction (OWP)

website, http://water.noaa.gov/about/nwm

 

Additionally, the full set of NWM output and a subset of forcing

files are available on NCEP web services at:

    http://nomads.ncep.noaa.gov/pub/data/nccf/com/nwm

    ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/nwm

    http://ftp.ncep.noaa.gov/data/nccf/com/nwm

 

 

 

Output Changes on the NCEP web services:

No directory structures or file name conventions will change

with this upgrade.  Users should refer to the V1.1 and V1.0 TINs

for information on filename and directory structures.

 

http://www.nws.noaa.gov/os/notification/tin16-30natl_water_model.htm

http://www.nws.noaa.gov/os/notification/scn17-41natl_water_modelaaa.htm

 

Changes were made to the internal contents of the output files. 

These include

-Adding three new variables (QSfcLatRunoff, QBucket,

QBtmVertRunoff) to the Short-Range and Analysis channel output

files

-Removing one variable (qlat) from the Analysis, Short-, Medium-

and Long-Range channel output files

-Changing the metadata variable "time" data type from "double"

to "integer"

-Changing the output variable "inflow" from "float" to "integer"

in the reservoir model output files from the Analysis, Short-,

Medium- and Long-Range configurations.

 

As in V1.1, users will find that long range products have enough

of a lag time in creation that they may appear in the previous

day’s output directory.  For example, long range mem 1 products

for the 18z cycle will not show up until the day after their

initialization time.  For this reason, users are encouraged to

look back in the previous dated directory for long range product

availability.

 

File availability time changes:

 

Due to the variability of the timing of observation input data

from the U.S. Geological Survey (USGS), an increased frequency

of running the observation aggregation process, and enhanced

parsing of quality control flags, the USGS timeslice files will

continue to vary in timing and updates throughout the day.

Output files from the NWM medium range forecast will now be

available up to 25 minutes earlier due to changes in the file

contents mentioned above.

 

Most NWM NetCDF output files are directly viewable using

standard NetCDF visualization utilities.  The exceptions are the

point-type NWM channel output files containing streamflow and

other variables.  In particular, due to storage space

limitations, the latitude and longitude of each point are stored

outside of the file, but are available at: 

 

ftp://ftp.nohrsc.noaa.gov/pub/staff/keicher/NWM_live/web/data_to

ols/NWM_v1.2_nc_tools_v1.tar.gz

 

Scripts are also available at this location which will append

this geospatial data to a user selected output file, enabling

viewing of channel output files within NetCDF visualization

utilities.

 

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

server via the following URLs:

 

http://para.nomads.ncep.noaa.gov/pub/data/nccf/com/nwm/para

 

NCEP encourages all users to ensure their decoders are flexible

and are able to adequately handle changes in content order 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 more general information about the NWM, please see:

  http://water.noaa.gov/about/nwm

 

Direct questions regarding this implementation to the contacts

below. NCEP will evaluate feedback and decide whether to proceed.

 

For questions on the science aspects, please contact:

    Brian Cosgrove

    OWP/Analysis and Prediction Division

    Silver Spring, MD

    301-427-9513

    brian.cosgrove@noaa.gov

 

For questions regarding the data flow aspects of these datasets,

please contact:

    Carissa Klemmer

    NCEP/NCO Dataflow Team

    College Park, Maryland

    301-683-0567

    ncep.list.pmb-dataflow@noaa.gov

 

NWS National Service Change Notices are online at:

 

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

 

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