[nws-changes] 20110727: RUC replacement-Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20110727: RUC replacement-Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Wed, 27 Jul 2011 13:24:19 -0600

-------- Original Message --------

307
NOUS41 KWBC 271900
PNSWSH

Technical Implementation Notice 11-36
National Weather Service Headquarters Washington DC
300 PM EDT Wed Jul 27 2011

To:        Subscribers:
           -Family of Services
           -NOAA Weather Wire Service
           -Emergency Managers Weather Information Network
           -NOAAPORT
           Other NWS Partners, Users and Employees

From:      Tim McClung
           Chief, Science Plans Brach
           Office of Science and Technology

Subject:   Notice of Intent to Replace Rapid Update Cycle (RUC)
           Model:  Effective Fall 2011

Sometime after mid-October 2011, the National Centers for
Environmental Prediction plans to replace the current Rapid
Update Cycle (RUC) modeling system with the Rapid Refresh (RR)
modeling system. More specifics, including an implementation
date, will be sent in the next two months.

Brief Description of Changes:

-Change of name of system from Rapid Update Cycle (RUC) to
 Rapid Refresh (RR)
-Replace RUC prediction model with WRF using ARW dynamic core
-Replace RUC 3-D variational analysis (3DVAR) with the Gridpoint
 Statistical Interpolation (GSI)
-Expand domain to cover Alaska and Caribbean basin

The transition of the Rapid Update Cycle into use of the WRF
model has been planned for more than 6 years. The Rapid Refresh
configuration allows the system to take advantage of the
community development of the WRF model and GSI data
assimilation, used in other NCEP systems including NAM and GFS,
while maintaining many of the elements of the RUC crucial to
aviation and severe weather forecasting, such as the diabatic
digital filter initialization, the assimilation of radar
reflectivity data, and the analysis of cloud hydrometeors using
METAR and satellite data.  The Rapid Refresh domain extends
hourly "rapid updating" to all of North America, including Alaska
and the Caribbean.

A full description of the changes can be found on the Earth
Sciences Research Laboratorys web page for the Rapid Refresh:

http://rapidrefresh.noaa.gov

Please note that the experimental 3-km High-Resolution Rapid
Refresh (HRRR) is not part of this implementation.

Model products:

Most of the output currently available from the RUC will be
available for the Rapid Refresh to ensure a smooth transition to
the new system.   This output includes:

- 13, 20, and 40-km Lambert Conformal grid data covering the
  CONUS region with output on pressure levels
- 13, 20, and 40-km Lambert Conformal grid data covering the
  CONUS region with output on native levels
- BUFR model station time series output (with an expanded list
  of stations to accompany the larger domain)

New data will include:

- Full-domain output on a 32-km Lambert Conformal grid, the only
  grid on which data covering the entire domain will be
  generated)
- Alaska data on an 11-km polar-stereographic grid

Data that will no longer be available are 80-km Lambert
Conformal grid data covering the CONUS region

A parallel version of the RR is being run at the Environmental
Modeling Center each hour with statistics being computed daily.
Forecast graphics are available at

  http://www.emc.ncep.noaa.gov/mmb/gmanikin/rap/para

Formal evaluation will begin in the fall of 2011, with data
files available from NCEP Central Operations, which will be
running the system in a real-time dedicated parallel.  The
location of this parallel test data will be sent in a follow-on
notification. Users who wish to get a head start on their
evaluation of test files to prepare for the transition can
obtain them from the EMC parallel at:

  ftp://ftp.emc.ncep.noaa.gov/mmb/mmbpll/rap

NCEP would encourage users to ensure their decoders are flexible
and are able to adequately handle changes in content order,
parameter fields changing 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 implementation.

For questions regarding these changes, please contact:

    Geoffrey Manikin
    NCEP/EMC Global Modeling Branch
    Camp Springs, Maryland
    301-763-8000 x7263
    geoffrey.manikin@xxxxxxxx
or
    Stan Benjamin
    NOAA/ESRL
    Boulder, CO
    303-497-6387
    stan.benjamin@xxxxxxxx

NWS National Technical Implementation Notices are online at:

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

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