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NOAA NAM - Downscaled NWP Project (DNG)

In 2008, NCEP began "in-house" processing of the North American Mesoscale (NAM) model smartinit code. This code had previously been run by local National Weather Service offices to provide a first guess for NDFD elements, but the local version of the code used a coarse, isobaric NAM output grid for the processing.

Running the code at NCEP allows the use of a high-resolution grid on native levels. This detail is critical for the downscaling process which adjusts temperature, dew point, and winds to a very high-resolution terrain field. Examples of the downscaling procedure over the CONUS, Hawaii, Alaska, and Puerto Rico will be shown.

Recently, NCEP adapted the probability of precipitation (PoP) products to an updated concept. The original code based its PoP primarily on high model predicted precipitation. A large amount of precipitation predicted by the model resulted in a large PoP value. The new method gives some weight to the amount of precipitation predicted by the NAM but also uses probability fields generated by the SREF to give a more realistic product.

NAM DNG analysis and prediction graphics

DNG Output grids https://docs.google.com/a/noaa.gov/file/d/0B_-GJGdRdReTc2RSQ1p3X3o4eWc/image?pagenumber=4&w=800 DNG Products

Recent NCEP DNG Reports

G. Manikin, et al. (2009, 19th NWP) S. Benjamin, (2007, NWP)

Recent Research & Development

Tsidulko, M. (2010): AMS 16th conf. Air Poll.: NMMB 4 km testing

NAM Information

NCEP NAM change log NAM-NEMS implementation (October, 2011) NMM-B Documentation

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