[Wrf-users] diff in NAM and NARR

Feng Liu fliu at mag.maricopa.gov
Mon Sep 14 09:34:58 MDT 2009

 Hi, Qian
NAM: North American Model meteorology files have 40km resolution at 3
hour intervals. All files after Feb 2008 are grib2, and current year
files are available. (See NCEP Eta/NAM ds609.2)
NARR: The North American Regional Reanalysis meteorology has 32km
resolution at 3 hour intervals so it is even more detailed than NAM.
NARR has no files for the current year. (see NCEP GRIB GDAS ds083.0)
Good luck.

-----Original Message-----
From: wrf-users-bounces at ucar.edu [mailto:wrf-users-bounces at ucar.edu] On
Behalf Of Qian Tan
Sent: Friday, September 11, 2009 9:13 AM
To: wrf-users at ucar.edu
Subject: [Wrf-users] diff in NAM and NARR

Dear WRF users,

Can someone tell me the major difference between NAM and NARR when we
prepare input to WPS?

So far what I have found:

They both cover North America, with similar resolution.

NAM, reanalysis mode has few months delay, and it has the forecast mode.

NARR has half month delay, and you need some extra steps to prepare them
for WPS since not all required fields are there.

What is other difference? In term of WRF performance, which one is


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