NCEP ENSEMBLE GRIB DATA INFO
Information on this page:
Other relevant information:
Fast
Downloading of GRIB Files
(partial http transfers)
Updated
documentation for ensemble data information
Getting
NCEP Ensemble
data
via anonymous ftp
NCEP Ensemble data are currently available via anonymous ftp on 3
different
servers:
Typically, the NCEP ftp server will have a few recent days worth of
data
on-line, while the NWS server will only have the data for the current
day.
The data are grouped together according to variable. For example, the
file
enspost.T00Z.z500 will contain all 12 ensemble perturbation forecasts
for
500 mb height for 00z for the day given by the directory name. The
following
variables are available in this file:
precipitation (precip)
precipitation probabilities (ensspf)
mean sea level pressure (prmsl)
rh 700 mb (rh700)
T 2 meters (t2m)
T Max, T Min (tmax, tmin)
T 850 mb (t850)
u-comp 10 meters, v-comp 10 meters (u10m, v10m)
u-comp 250 mb, v-comp 250 mb (u250, v250)
u-comp 500 mb, v-comp 500 mb (u500, v500)
u-comp 850 mb, v-comp 850 mb (u850, v850)
250 mb gp height (z250)
500 mb gp height (z500)
850 mb gp height (z850)
1000 mb gp height (z1000)
For each variable, 1 file is written for the 12 00z perturbations and 1
file is written for the 5 12z perturbations. In each file and for each
perturbation, data are included every 12 hours from valid time = 00h to
384h. GRIB index files are also included on these servers in the same
directory
as the GRIB data files, and are identified by the "i" after the
parameter
identifier in the file name (e.g., enspost.T00Z.z500i ).
In addition, a file containing probabilistic
quantitative precipitation forecasts (PQPF), derived from the
ensemble,
is also available.
FTP Access to NCEP
GRIB
decoding software
You can find NCEP GRIB decoding software at the following location:
The NCEP ftp server:
ftp://ftp.ncep.noaa.gov/pub/nws/nmc/codes/
Take a look at the README file. Read that and then cd to the
subdirectories
to download the software.
*** You can find help
using NCEP's GRIB
decoding
software by clicking
here ***
Understanding
the
Ensemble
GRIB PDS extension
NCO maintains a web document describing the format of the NCEP GRIB
section for ensembles:
NCEP
USE OF THE EXTENDED GRIB PDS SECTION
FOR DESCRIBING ENSEMBLE OUTPUT