NOUS41 KWBC 181744



Technical Implementation Notice 15-08

National Weather Service Headquarters Washington DC

1245 PM EST Wed Feb 18 2015


To:       Subscribers:

          -Family of Services

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners and Employees


From:     Tim McClung

          Chief, Science Plans Branch

          Office of Science and Technology


Subject:  RTMA and URMA Upgrade: Effective April 7, 2015


Effective on or about Tuesday, April 7, 2015, beginning with

the 1300 Universal Coordinated Time (UTC) cycle, the National

Centers for Environmental Prediction (NCEP) will upgrade the

Real-Time Mesoscale Analysis (RTMA) and the Unrestricted

Mesoscale Analysis (URMA) as follows:


- Changes to model components

- Addition of new product fields, including onto NOAAPORT

- Product output changes


1) Model Changes


- For the RTMA and URMA 2.5 km CONUS grids, replace the 13km

  RAP downscaled 1h-forecast with a blend of the downscaled

  3km HRRR 1h-forecast and a 4 km NAM-nest (variable-length)

  forecast for the first guess


- Enhance the GSI code to include a terrain-aware gross error

  check for all observations and a buddy-check for temperature



- Extend the look-back period for the 6-hourly URMA

  precipitation from 1-7 days:

  - Currently the 6-hourly Stage IV is a mosaic of the

    6-hourly Quantitative Precipitation Estimates (QPEs) from

    the 12 CONUS River Forecast Centers (RFCs). For this

    release, NCEP first produces 6-hourly totals from the

    8 Eastern/Central RFCs' hourly QPEs then combine these

    6-hourly totals with the four Western RFCs' (Northwest

    (NW) RFC, California-Nevada (CN) RFC, Colorado Basin (CB)

    RFC, Missouri Basin (MB) RFC) 6-hourly QPEs to arrive at

    a 6-hourly CONUS mosaic


  - Hourly Stage IV will be re-made hourly if there is new

    input after valid time for the next 23 hours, then again

    at 1, 3, 5 and 7 days after valid time


  - The 6-hourly Stage IV/URMA will be re-made hourly if

    there is new input for 24 hours after valid time, then

    the four 6-hourly mosaics covering a 12Z-12Z 24 hour

    period will be re-made at 1, 3, 5 and 7 days after the

    ending 12Z (the 6-hourly Stage IV precipitation is

    remapped to the 2.5km NDFD-CONUS and NWRFC grids at each

    update as precipitation URMA)


  - Each remake of the 6-hourly mosaic is followed by its

    remapping to the 2.5km CONUS and NWRFC grids as

    precipitation URMA


The use of the higher resolution models to build the first

guess and the enhanced observation quality control results in

an overall improved analysis for the 2DVar variables of the

RTMA/URMA, especially 2 meter temperature and 10 meter winds.

Using the primary hourly QPEs from the above eight

Eastern/Central RFCs and the overall extension of the look-

back period to 7 days results in a more accurate final URMA



2) Addition of Variables


NCEP is adding fields of Total Cloud Amount (TCDC) analysis

and Total Cloud Amount analysis uncertainty to the RTMA and

URMA GRIB2 files available on the NCEP ftp, http and NOMADS

servers via the following URLs (YYYYMMDD is the year, month



- Total Cloud Amount (TCDC) analysis will be added to:






- Total Cloud Amount (TCDC) analysis uncertainty will be added to:






These additional RTMA and URMA variables will also be added to

the ftp server for NDGD downloads and to NOAAPORT


     file name - ds.tcdc.bin


  WMO header information will be as follows:

  T1T2A1A2ii cccc where

    T1 = L

    T2 = A - Total cloud cover

    A1 specifies the grid id as follows

      I - RTMA CONUS 2.5 km grid 184

      Q - URMA CONUS 2.5 km grid 184

    A2 specifies the forecast hour as follows:

      A = 00 (Analysis)

    ii = 98 - Surface or 2m above ground

    cccc = KWBR


      LAIA98 KWBR         RTMA TCDC Analysis

      LAIA98 KWBR         RTMA TCDC Analysis Uncertainty

      LAQA98 KWBR         URMA TCDC Analysis

      LAQA98 KWBR         URMA TCDC Analysis Uncertainty


3) Output Changes


All filenames and paths given are on the NCEP ftp server, the

NCEP http server, or NCEP NOMADS server, respectively, via the

following URLs (YYYYMMDD is the year, month, day):


- RTMA 2.5 km precipitation data will be relocated from: 


    to -> data/nccf/com/rtma/prod/rtma2p5.YYYYMMDD


- URMA 2.5 km precipitation file names will change from:


    to -> urma2p5.YYYYMMDDCC.pcp_06h.184.grb2


    to -> urma2p5.YYYYMMDDCC.pcp_06h.188.grb2


- RTMA 2.5 km precipitation file names will change from:


    to -> rtma2p5.YYYYMMDDCC.pcp.184.grb2



4) Sample Parallel Data


A parallel feed of data will be available on the NCEP HTTP

server in mid-February. The parallel data will be available

via the following URLs:


More information about the RTMA and URMA is available at:


Information about the precipitation URMA, with links to

parallel run data directories:


For questions regarding these changes, please contact:


    Geoff DiMego

    NCEP/EMC Mesoscale Modeling Branch

    College Park, Maryland



For questions regarding the data flow aspects of these data

sets, please contact:


    Carissa Klemmer

    NCEP/NCO Dataflow Team

    College Park, Maryland



NWS National Technical Implementation Notices are online at: