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Meteorological Development Laboratory

MOS Coop Products

MDL has developed MOS forecast equations based on output from NCEP's GFS model for maximum and minimum temperature and snowfall amount guidance for approximately 7400 cooperative observer sites in the United States. Development of snowfall amount guidance was also done based on the NAM model. These developments were done using NCDC's TD-3200 Cooperative Summary of the Day reports.

Maximum/Minimum Temperature Guidance

The short-range text messages contains maximum and minimum temperatures for 1 to 4 days from the 0000, 0600, 1200, and 1800 UTC GFS model runs. The extended-range text message contains maximum and minimum temperature forecasts for 1 to 8 days from the 0000 UTC GFS model run. In early 2005, we began producing an extended-range text product from the 1200 UTC GFS model run as well. We currently have no plans to produce a COOP temperature guidance text message based on the NAM model. The stations in the message are listed alphabetically by state, using their NWS site identifier. For max/min temperature, guidance is available for approximately 5600 sites. Sample messages of the GFS-based text messages for all 4 cycles are available here.

Starting with the 1200 UTC cycle on May 25, 2004, the forecasts will be available on the NWS ftp server, which has 24x7 operational support. The products will continue to be available on our webpages, which are only supported during regular business hours. The locations for both are given below. We will begin distributing the messages to AWIPS via the SBN on February 8, 2005. The NWS announcement of this change is TIN 04-54. The WMO and AWIPS headers will be:


Location of messages on NWS FTP Server (TGFTP):
Short-range GFS-based Maximum and Minimum Temperature Guidance
Extended-range GFS-based Maximum and Minimum Temperature Guidance

On this server, the files are stored in directories called RD.YYYYMMDD, where YYYYMMDD is the year, month and day. Within the RD.YYYYMMDD directory, the files will be named cy.XX.txt, where XX is the cycle. Data will be available for two days.

Location of messages on webserver:
Short-range GFS-based Maximum and Minimum Temperature Guidance
Extended-range GFS-based Maximum and Minimum Temperature Guidance

Snowfall Guidance

Snowfall guidance is produced for roughly 7400 cooperative observer sites for both the GFS and NAM models. At this time the coop snowfall guidance is available only in graphical format. The GFS- and NAM-based Coop Snowfall guidance is available from September 1st through May 31st.

GFS-based Gridded MOS (listed under 24Hr Snow Amount)
GFS short-range graphical depictions (listed under Snowfall/Precipitation Type)
NAM graphical depictions (listed under Snowfall)

Additional Information

For a description of the GFS MOS snowfall amount development, please see the following papers:
Producing MOS Snowfall Amount Forecasts from Cooperative Observer Reports

Using gridded MOS techniques to derive snowfall climatologies.

For more information about NCDC data and the cooperative observing network, please see NCDC's website.

National Weather Service
Office Of Science and Technology
Meteorological Development Laboratory
Statistical Modeling Branch
1325 East West Highway
Silver Spring, MD 20910
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Page last Modified: Thursday, 08 July 2010 18:37 UTC