CORe is an atmospheric reanalysis from the Climate Prediction Center NCEP/NWS/NOAA with collaboration with the Environmental Modeling Center NCEP/NWS/NOAA and Physical Sciences Laboratory NOAA. CORe analyses can be obtained from the NCEP Nomads site, and the NODD (NOAA Open Data Dissemination) service which distributes NOAA data by the cloud.

CORe:         NCEP Nomads                      NODD (cloud)

length        last 7 days                      1950 to near real-time
file names    NCO standard (names not unique)  simplified and unique
https access  free                             free
ens mean      3 hourly                         3 hourly, daily, monthly
ens members   yes                              no
ens stats     yes                              no
restart IC    no                               no                  IC = initial conditions
secondary     no                               no 
URL           https://nomads.ncep.noaa.gov     https://storage.googleapis.com/noaa-nws-ncep-core/
Subsetting    regions, gbl grids               gbl grids           gbl = global
OpenDAP       no                               no                  points, subregions, grids
grib filter   yes                              no                  subregions, grids
grid^         yes                              yes                 gbl grids
software      many                             get_core.py
scope         grib files                       ens means #
info          info                             get_core.txt
status        when CORe is operational         1950-present
delay         1.x day                          1.x+ day
Questions
tech Q        NCO (24 hour)                    NODD                network and server issues
file Q        NCO (24 hour)                    CPC                 questions about missing files
CORe sci Q    -                                CPC office hours    CORe science questions
gen sci Q     NCEP                             -                   general science questions
grib Q        -                                -                   see software documentation

cloud access  no                               Google Cloud (bucket: noaa-nws-ncep-core)

* Files with restricted observations are not public, including BUFR and diagnostic files
^ grids by partial https downloading, using index (*.idx) files
  Nomads: see https://nomads.ncep.noaa.gov/info.php?page=fastdownload
  NODD: Google Cloud can only download one byte range at a time
    so need special versions of the partial https downloading software
    For the CORe, see: get_core.py
# we expect to add more data types depending on demand

The NCEP Nomads site is run by NCEP Central Operations (NCO) using data from the operational run of CORe. You can submit help tickets, subscribe to mailing lists and read their documentation at NCO help and information. NCO has 24 hour support. More information will be provided after CORe data is sent the Nomads site.

The CORe files on NODD can be downloaded using https://ftp.cpc.ncep.noaa.gov/CORe/get_core/get_core.py. Documentation is in https://ftp.cpc.ncep.noaa.gov/CORe/get_core/get_core.txt. The Climate Prediction Center (CPC) is responsible for updating the NODD archive, and maintaining get_core.py. CPC support is limited to office hours.

In the event that CORe needs to be rerun, it is expected that the new analyses would be sent to the NODD archive and not NCEP's nomads site.

CORe home page regridding CORe files

Comments: Leigh.Zhang@noaa.gov
Created Sep 9, 2025