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NCEP Model Evaluation Subscribers, The Environmental Modeling Center (EMC) has proposed an upgrade to the North American Mesoscale (NAM) Analysis and Forecast System. The changes include: 1. Changes to the WRF-NMM model physics/dynamics: vertical mixing/diffusionof individual hydrometeor species, doubling the absorption coefficients for cloud water/ice in the radiation parameterization, and changes to the land-surface physics
to improve model forecasts of cool season near-surface fields.2. Use GDAS atmospheric states for the analysis first guess at the start of each NDAS cycle (“partial cycling'); upgrade the WRF pre-processing by replacing WRF-SI with
the WRF Preprocessing System (WPS). 3. Upgrade to the latest version of the NAM GSI analysis code. 4. Assimilation of new observation types (METOP, TAMDAR, Canadian AMDAR).5. All WRF-NMM forecast model changes described above will be simultaneously
implemented into the DGEX forecast system for consistency with the NAM, from which the DGEX is initialized. Near Real-Time Parallel Data FTP:ftp.ncep.noaa.gov/pub/data/nccf/com/nam/para/nam.YYYYMMDD <ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nam/para/nam.YYYYMMDD>
HTTP: http://www.ftp.ncep.noaa.gov/data/nccf/com/nam/para/nam.YYYYMMDD In addition, we are sending GEMPAK data to the WOC at: FTP:ftp.ncep.noaa.gov/pub/data/nccf/com/nawips/para/nam.YYYYMMDD <ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/nawips/para/nam.YYYYMMDD>
HTTP: http://www.ftp.ncep.noaa.gov/data/nccf/com/nawips/para/nam.YYYYMMDDWe will make the model output available for 30 days starting Tuesday, 14 October so that end-users of the NAM data can verify that no unforeseen changes have been introduced.
Any comments on this proposed change will be appreciated. Any feedback you wish to provide during the evaluation period should be emailed toNCEP.List.ModelEvalFeedback@xxxxxxxx <mailto:NCEP.List.ModelEvalFeedback@xxxxxxxx>, prior to 13 November, 2008.
Additional information on the NAM performance can be found at: http://www.emc.ncep.noaa.gov/mmb/mmbpll/nampllstats_fall2008/ ;
cumulative stats for real-time NAM parallel (1 August 2008 - present)http://www.emc.ncep.noaa.gov/mmb/mmbpll/pll12stats.namp_retro_26feb07-31mar07/ :
cumulative stats for cold-season retrospective test of NAM parallel ( 26 February 2007 - 31 March 2007) Thanks Dan Starosta ------------------------------------------------------------------------ _______________________________________________ NCEP.List.ModelEvalInfo mailing list NCEP.List.ModelEvalInfo@xxxxxxxx
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