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GCIP/EOP Surface: Precipitation NCEP/EMC 4KM Gridded Data (GRIB) Stage IV Data


The Stage IV analysis is based on the multi-sensor hourly/6-hourly 'Stage III' analyses (on local 4km polar-stereographic grids) produced by the 12 River Forecast Centers (RFCs) in CONUS. NCEP mosaics the Stage III into a national product (the Stage IV). Hourly, 6-hourly and 24-hourly (accumulated from the 6-hourly) analyses are available. The Stage IV differs from the NCEP Stage II chiefly in that the NCEP Stage II contains no manual quality control (QC), while the Stage IV benefits from manual QC performed on the Stage III data at the RFCs. As of April 2017 this data includes Alaska and Puerto Rico stations.

Archive note

These data are processed manually monthly, so the date new data are available varies. The data for each month are received from NCEP/EMC around the second week of the following month, and generally loaded within a few days of receipt. If data have not been received by the 20th of the month, then NCEP/EMC is contacted for an update. Since this is a manual process, dates are affected by the availability of EOL staff. If data are not available by the 22nd, please contact us for an update.

System order size limits are about 6 months of data. If you need to download the entire dataset at once immediately, please contact us for alternate download arrangements (subject to EOL staff availability).

January 18, 2019 - It was noticed that the Alaska and Puerto Rico stations were not actually included in the dataset as mentioned in the data description.  As of this date, all the data (from April 2017) for the Alaska and Puerto Rico stations are now included in this dataset.

Data access

  • ORDER data for delivery by FTP

Additional information

Data Quality final
  • 1.0 (2011-08-11)
Metadata download

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Related projects
Spatial Type point
Frequency hourly
Language English
Related links

Temporal coverage

Begin datetime 2002-01-01 00:00:00
End datetime 2019-08-31 23:00:00

Spatial coverage

Map data from IBCSO, IBCAO, and Global Topography.

Maximum (North) Latitude: 71.413, Minimum (South) Latitude: 17.853
Minimum (West) Longitude: -176.836, Maximum (East) Longitude: -65.544

Primary point of contact information

Ying Lin <>

Additional contact information


Example citation following ESIP guidelines:

Lin, Y. 2011. GCIP/EOP Surface: Precipitation NCEP/EMC 4KM Gridded Data (GRIB) Stage IV Data. Version 1.0. UCAR/NCAR - Earth Observing Laboratory. Accessed 17 Oct 2019.

Today's date is shown: please replace with the date of your most recent access.

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