Welcome

Welcome to the RTMA/URMA VLab community!

The purpose of this community is to facilitate feedback and discussion on the RTMA/URMA system. 

Meeting notes are available under the Google Drive Folder linked above.

To learn more about our next upgrade, see the asset publication below.

Use the System Overview to learn more about the system in general.

Use the forum to ask questions about the system and join the discussion with other users and the development team. 

Note that there are two forums: one for precipitation issues and one for all other variables.

You can post to the precip issues forum by sending an email to qpe.rtma.urma.feedback.vlab@noaa.gov.  For all other issues, you can post by sending an email to rtma.feedback.vlab@noaa.gov.  Please note that you must have a user account to post to the forum.  If you do not have an account, please contact matthew.t.morris@noaa.gov.

We recently added the ability for NWS Regional or WFO personnel to request that stations be removed from the analysis.  To access this, click on the "Station Reject Lists and Requests" tab.

There has been recent interest in knowing exact station locations, especially those of METAR sites.  Our METAR information table is under the "METAR Location Info" tab.

Users may also be interested in the National Blend of Models VLab community.

We appreciate any feedback on how this page or community could be improved.  You can submit such feedback via the above email handle or forum.

 

What's New

December 2017 Implementation Summary

Document

Overview of upgrade scheduled for December 2017. Note that this was originally scheduled for October 2017, but has been pushed back due to technical issues.

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Modified Date
10/31/17

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A Few URMA Questions

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Joe Lester, modified 6 Months ago.

A Few URMA Questions

Youngling Posts: 12 Join Date: 6/12/17 Recent Posts

A few questions I was hoping you could answer for me. I'm trying to understand the URMA process a little better. I use this site for viewing which obs are used and which are rejected: https://ftp.emc.ncep.noaa.gov/mmb/rtma2/for_eval/ob_files/  (1) Why are "ob value" and the reported temp often different? This applies to all parameters. (2) Why are so many stations NOT used for wind speeds/gusts? (3) Can I suggest additional stations to use when I don't see them plotted? (4) For our airport (KBIL), the plotted marker and the actual location of the ASOS are in different locations that are about 250' of elevation apart...is this causing differences in obs/bg values? I have attached an image w/ my examples. Thanks!

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Matthew Morris, modified 6 Months ago.

RE: A Few URMA Questions

Youngling Posts: 156 Join Date: 12/6/17 Recent Posts
Hi Joe,

1) It appears there is a mismatch between the time of the observations and the KML file you are referencing.  October 18, 12:53 PM MDT corresponds to 1853 UTC and the 19Z URMA.  In the KML files, the observation value is listed as 60.89F, consistent with the observation table (61F).  I believe you are looking at the KML file from 19Z on the 17th.

2) Wind speed and gust observations from mesonet providers are rejected, by default, unless the provider or individual station is "trusted".  In the case you've shown, the observation was rejected for failing the gross error check.  The gross error check will reject obs if abs(ob-guess)/oberror is greater than a prescribed maximum ratio (R).  For wind speed, R=8.0 for METARS and R=5.0 for mesonets.  For wind gust, R=5.0 for both METARS and mesonets.

3) Yes, you can suggest these additional stations, and we will see if it is possible to add them.  This would require some coordination and may not be possible for all stations, however.

4) The RTMA is a 2.5 km resolution system, and the values are intended to serve as an average expected value for the grid box.  Therefore, the slight displacement you see likely isn't having a significant impact on the analysis.

Please let us know if you have any other questions.

Thanks,
Matt

On Wed, Oct 18, 2023 at 11:19 PM VLab Notifications <VLab.Notifications@noaa.gov> wrote:

A few questions I was hoping you could answer for me. I'm trying to understand the URMA process a little better. I use this site for viewing which obs are used and which are rejected: https://ftp.emc.ncep.noaa.gov/mmb/rtma2/for_eval/ob_files/  (1) Why are "ob value" and the reported temp often different? This applies to all parameters. (2) Why are so many stations NOT used for wind speeds/gusts? (3) Can I suggest additional stations to use when I don't see them plotted? (4) For our airport (KBIL), the plotted marker and the actual location of the ASOS are in different locations that are about 250' of elevation apart...is this causing differences in obs/bg values? I have attached an image w/ my examples. Thanks!


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Joe Lester RTMA/URMA Discussion Group Virtual Lab Forum https://vlab.noaa.gov/web/715073/discussions-forums-/-/message_boards/view_message/32667762VLab.Notifications@noaa.gov


--
Matthew Morris
SAIC at NOAA/NWS/NCEP/EMC
5830 University Research Ct., Rm. 2038
College Park, MD 20740
301-683-3758

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  • 2011 RTMA Paper (Weather and Forecasting)

    The most recent peer-reviewed paper on the RTMA. Published in Weather and Forecasting in 2011.
    7 Visits

  • Public RTMA/URMA Viewer

    Another viewer of the current RTMA/URMA, with an archive going back 24 hours. This version is open to the public, but does not contain information about the (many) restricted obs used.
    52 Visits

  • RAP downscaling conference preprint (23rd IIPS)

    This link is to a presentation from the (then) RUC group on how the downscaling process works. Although we now use the RAP, HRRR, and NAM, the logic of the downscaling code is mostly unchanged from this point.
    2 Visits