[nws-changes] 20081023: RUC evaluation

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20081023: RUC evaluation
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Thu, 23 Oct 2008 08:03:43 -0600

To all NCEP Model Evaluation Subscribers

                                                  Chris Caruso Magee

daniel starosta wrote:

NCEP Model Evaluation Subscribers,

The Environmental Modeling Center (EMC) has proposed an upgrade to the Rapid Update Cycle (RUC).

The changes include:

1. Upgrades to algorithms for RUC analysis 1. Use of mesonet wind data 2. Assimilation of 3-d radar reflectivity

         3. Assimilation of TAMDAR aircraft observations including
            moisture observations
         4. Revision to observation error and background error for
            moisture observations
         5. Improved QC based on observation-background differences
   2. Upgrades to algorithms for RUC model
         1. Specification of latent heating from radar reflectivity
            during pre-forecast diabatic digital filter initialization
            (DFI) already in RUC model
         2. Use of RRTM longwave radiation parameterization replacing
            current Dudhia longwave radiation, warm bias at surface in

warm season, and decreasing cold bias at night over snow cover

         3. Modifications to Grell-Devenyi convective parameterization
            to reduce excessive areal coverage for light precipitation
            and to introduce non-local subsidence warming
         4. Modification to RUC land-surface model for snow density to
            prevent excessive surface temperature over fresh snow
   3. Upgrade to RUC post-processing code
         1. Add 3 reflectivity fields to isobaric (ruc_presm) output
            fields for max, 1-km, and 4-km levels, similar to those
            products already produced for the NAM
         2. Add accumulated total precipitation and snow fields, also
            following NAM fields
         3. Modify ceiling diagnostic to avoid excessive LIFR (Low
            Instrument Flight Rules) conditions. Ed. Pre-processing of
            3-d radar reflectivity to ~13km resolution from
            higher-resolution tiles **


*N**ear Rea**l-Time Parallel Data*

Beginning Tuesday 16 September 2008, parallel data will be at:

FTP: ftp://ncep.noaa.gov/pub/data/nccf/com/ruc/test/ruc2a.YYYYMMDD <http://www.ftp.ncep.noaa.gov/data/nccf/com/ruc/test/ruc2a.YYYYMMDD>

HTTP:
http://www.ftp.ncep.noaa.gov/data/nccf/com/ruc/test/ruc2a.YYYYMMDD

In addition, we are sending GEMPAK data to the WOC at:

FTP:

ftp.ncep.noaa.gov/pub/data/nccf/com/nawips/test/ruc2.YYYYMMDD <ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nawips/test/ruc2.YYYYMMDD>

HTTP:
http://www.ftp.ncep.noaa.gov/data/nccf/com/nawips/test/ruc2.YYYYMMDD

We will make the model output available for 30 days starting Tuesday, 16 September.

Any comments on this proposed change will be appreciated. Any feedback
you wish to provide during the evaluation period should be emailed to

NCEP.List.ModelEvalFeedback@xxxxxxxx <mailto:NCEP.List.ModelEvalFeedback@xxxxxxxx>, prior to 15 October 2008.

Thanks

Dan Starosta

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