IEM Provided MRMS Archives
Archive Changelog
- 30 Sep 2025: Document the "Path Forward" for the MRMS hourly zip files.
- 24 Sep 2025: Attempting to consolidate documentation on this page and start to document an upcoming archive data removal of hourly zip files per Iowa State cloud storage changes.
"Path Forward" for MRMS hourly zip archive
The IEM has been providing an archive of hourly MRMS zip files since September 2019. This archive consisted of some modest local storage caching recent data and then the rest being made available via cloud storage. Due to a quota change with the cloud storage, this archive is no longer viable in its entirety. So here is a listing of the path forward for this archive.
27 Sep 2019 - 30 Oct 2020: This portion of the archive is not available via the NOAA AWS OpenData MRMS archive. The data also represents a period prior to a major MRMS upgrade that happened, which makes it not as seemlessly comparable with MRMS data after. NOAA made a decision to not backfill this data to AWS OpenData for this reason. There is space locally to continue to host this data and it will be kept around until perhaps better things are made available from NOAA...
Nov 2020 - Present: This portion of the archive should be available via the NOAA AWS OpenData MRMS archive. There is limited utility for it to be kept around, but some folks may have a usage for the convience factor of having everything zipped up in one file. So going forward, a very limited cache will be kept around, which should be a month or two of data. Presently, a cross checking process is running to ensure the AWS archive contains everything found within this archive. So you will notice files start being removed once the cross check completes.
MRMS Project Overview
The MRMS Project is an important part of the IEM's data curation effort. It directly drives the rainfall product within the Daily Erosion Project and is used in a variety of other applications. The IEM has been archiving and generating products from MRMS since the early days running at NSSL prior to being operationalized by the NWS NCEP.
The NSSL MRMS website has a handy Grib Table Listing, which helps with knowing what is available and grib file units.
AWS OpenData Archive
Starting in October 2020, MRMS started to be archived at AWS OpenData, which obsoleted much of the utility of IEM's raw grib product archives. However, this archive does not include what the IEM archived prior to Oct 2020 back to about Sep 2019.
MTArchive Site
To support the Daily Erosion Project and other applications, the IEM archived a select number of MRMS grib fields at per UTC date trees on the MTArchive site , which contains products back to October 2014 (NCEP implementation) and also a "Tile2" binary file (which covered Iowa) from the NSSL days.
The MTArchive site also contains an archive example of the MRMS ReAnalysis, but a more useful copy exists on AWS OpenData.
Real-time Files
The IEM also has a cache of near realtime grib files on metfs1 service, but its utility is not as useful as what you can find at the official MRMS Data Website.