[nws-changes] 20131112 upgrade of RT initial implementation of URMA Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20131112 upgrade of RT initial implementation of URMA Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Tue, 12 Nov 2013 12:22:29 -0700

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

846
NOUS41 KWBC 121918
PNSWSH

National Weather Service Headquarters Washington DC
220 PM EST Tue Nov 12 2013

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

          Chief, Science Plans Branch
          Office of Science and Technology

          Effective December 18, 2013

1400 Universal Coordinated Time (UTC) cycle, the National Centers
for Environmental Prediction (NCEP) will upgrade the Real-Time
Mesoscale Analysis (RTMA) and introduce the Unrestricted
Mesoscale Analysis (URMA). The upgraded RTMA includes:

-Adding variables
-Changing resolution for Alaska
-Adding a new output grid
-Removing the 5km CONUS products except for those on NOAAPORT

URMA is an improved analysis created 6 hours after analysis time
(with the exception of precip, see URMA section below) to
provide a more complete set of observational data. There will
also be a change to the products available from the North
American Model (NAM) Downscaled Numerical Guidance (DNG) system.
More specific details of the changes are provided below.

Addition of New Fields:

Hourly grids of 10m wind gust and surface visibility will be
added to CONUS at 2.5km horizontal resolution, and Hawaii and
Puerto Rico at 2.5km. Similar grids, except 3-hourly, will be
added for Guam at 2.5km. These fields will be available in the
existing RTMA output files and will be disseminated over NOAAPORT
using the WMO headers listed in Table 1 below.

Change of Resolution for Alaska grid:

The current Alaska grid 6km resolution will be replaced with a
3km resolution grid (grid number 91). The output products will
contain hourly grids of 2m temperature, 2m dew point, 10m wind
speed, 10m wind direction, 10m u-wind component, 10m v-wind
component, 10m wind gust, surface pressure, surface visibility,
and model terrain height. The geographic coverage of the grid is
online at:

www.nco.ncep.noaa.gov/pmb/changes/docs/akrtma3p0_domain.png .

The 3km products will be disseminated via the NCEP server, NOMADS
and NOAAPORT. In addition, the 6km grids currently available in
the National Digital Guidance Database (NDGD) at

ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/DF.gr2/DC.ndgd/GT.rt
ma/AR.alaska/

will be replaced by the new 3km grids. The 6km Alaska grids will
remain on NOAAPORT until such time as the Advanced Weather and
Information Processing System (AWIPS) can convert to using the
3km grids. The WMO headers for the 3km AK grids are listed below
in Table 2

Addition of new grids for NWRFC:

New output grids will be generated on a 2.5km grid that covers
the area of responsibility of the North West River Forecast
Center (NWRFC).  The geographic coverage of the grid can be seen
at:

http://www.nco.ncep.noaa.gov/pmb/changes/docs/nwrfc_domain.png.

The output products will contain hourly grids of 2m temperature,
2m dew point, 10m wind speed, 10m wind direction, 10m u-wind
component, 10m v-wind component, 10-m wind gust, surface
pressure, surface visibility, and model terrain height.  The
NWRFC products will be disseminated via the NCEP server and will
be available for http download on NOMADS.

Implementation of URMA:

Updated grids for the 2.5km CONUS and NWRFC domains, along with
the grids of 6-hour accumulated precipitation will be referred to
as the Unrestricted Mesoscale Analysis (URMA). URMA represents an
improved analysis more suited for verification since it adds
nearly all of the observations which are not used for the initial
analysis due to transmission latency issues. Grids of 2m
temperature, 2m dew point, 10m wind speed, 10m wind direction,
10m u-wind component, 10m v-wind component, 10-m wind gust,
surface pressure, and surface visibility will be made and
distributed 6 hours after the initial grids are made.

URMA will also include 6-hourly grids of accumulated
precipitation, remapped from the NCEP stage-IV precipitation.
The 6-hourly precipitation accumulation fields covering a 24h
(12Z-12Z) period are available beginning at 15:35 UTC; the CONUS
mosaic is remade each hour as NCEPS receives new regional
analyses from RFCs. Complete CONUS coverage is generally achieved
by 21:35 UTC.

With the exception of the precipitation grids, each of the above
analysis grids will be accompanied by a grid of the corresponding
analysis uncertainty. The GRIB encoding for the URMA grids will
be the same as that for the RTMA grids for the same elements,
except that the generating model process number for URMA will be
118 (it is 109 for the RTMA). URMA will be available on the NCEP
server, NOMADS, NDGD, and will be sent over NOAAPORT with the WMO
headers listed in Table 2

Change in filenames and directory structure:

Previously, the grids for the analysis and the analysis error
were contained in the same output files. This file will be split
into an analysis-only file and an analysis error-only file.  On
NOMADS and the NCEP server, the following three filenames will be
available, with this example the 0000 UTC cycle for 2.5km CONUS:

  rtma2p5.t00z.2dvaranl_ndfd.grb2  -- analysis grids
  rtma2p5.t00z.2dvarerr_ndfd.grb2  -- analysis error
  rtma2p5.t00z.2dvarges_ndfd.grb2  -- first guess field

In addition, the directory structure under which the RTMA
products are available on the NCEP server will change. Today, the
files are available in directories:

 ../com/{model}/prod/{model}.YYYYMMDD

where {model} is akrtma, gurtma, hirtma, prrtma, rtma, and
rtma2p5, depending on geographic region.  With this upgrade, the
first {model} will be replaced with a generic "rtma" directory
name, and then the multiple geographic region names will follow
after the "prod" directory level.

Removal of 5km CONUS RTMA products:

In TIN 11-20, NCEP announced that the 2.5km CONUS RTMA products
were a replacement for the 5km grids.  The 5km products had to be
retained until such time as AWIPS could transition to the 2.5km
grids.  While the 5km grids will remain on NOAAPORT for a while
longer, NCEP will remove the 5km CONUS grids from NOMADS and the
NCEP ftp server with this upgrade.

Additional RTMA enhancements:

The old grids for CONUS at 5km and Alaska at 6km that will be
distributed only on NOAAPORT will henceforth be sampled from the
corresponding double-resolution grids, thus benefiting from the
more recent, improved science used to create the latter.

An hourly cross-validation will be added to CONUS RTMA at 2.5km
and URMA at 2.5km.

There will be improved quality of the grids of surface pressure
for Alaska, Hawaii and Puerto Rico thanks to the use of an
improved background field.

Associated change to the NAM DNG:

The NAM DNG is used as input to the RTMA.  To support some of the
changes to the RTMA system, more NAM DNG data is being made
available. Output will now be available hourly up to forecast
hour 12 for the Alaska, Hawaii and Puerto Rico domains. In
addition, 10m wind gusts and surface visibility will be added
hourly out to forecast hour 12, while today it is only available
every 3 hours.  The NAM DNG products can be found at

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

with filenames with *smart* in the name.

More information about the RTMA and URMA is available at:

http://www.emc.ncep.noaa.gov/mmb/rtma/para/

A consistent parallel feed of data will be available on the NCEP
server via the following URLs:

ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/rtma/para/

in content order, changes in the scaling factor component within
the product definition section (PDS) of the GRIB files, changes
to the GRIB Bit Map Section (BMS), 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.

Table 1: WMO Headings assigned to grids of wind gust and
visibility for all available domains. Here, * is C for Puerto
Rico, G for Guam, H for Hawaii, I for 2.5km CONUS RTMA, and K for
3km Alaska.  For URMA, * is Q for 2.5km CONUS URMA.

WMO HEADING      RTMA PARAMETERS
LN*A98 KWBR      wind gust analysis
LN*A98 KWBR      wind gust analysis uncertainty
LK*A98 KWBR      visibility analysis
LK*A98 KWBR      visibility analysis uncertainty

to URMA grids for 2.5km CONUS. Here, * is Q for 2.5km CONUS URMA,
and K for 3km Alaska RTMA.

WMO HEADING      RTMA PARAMETERS
LT*A98 KWBR      temperature analysis
LT*A98 KWBR      temperature analysis uncertainty
LR*A98 KWBR      dewpoint temperature analysis
LR*A98 KWBR      dewpoint temperature analysis uncertainty
LN*A98 KWBR      wind speed analysis
LN*A98 KWBR      wind speed analysis uncertainty
LN*A98 KWBR      wind direction analysis
LN*A98 KWBR      wind direction analysis uncertainty
LU*A98 KWBR      u wind component analysis
LV*A98 KWBR      v wind component analysis
LP*A98 KWBR      surface pressure analysis
LP*A98 KWBR      surface pressure analysis uncertainty
LH*A98 KWBR      RTMA model terrain height
LEIA98 KWBR      6-hour Accumulated precipitation (2.5km for
                 CONUS only)

    NCEP/EMC Mesoscale Modeling Branch
    College Park, Maryland
    301-683-3764
    geoff.dimego@xxxxxxxx

For questions regarding the dataflow aspects of these datasets,
please contact:

     NCEP/NCO Dataflow Team
     College Park, Maryland
     301-683-0567
     ncep.pmb.dataflow@xxxxxxxx