NOUS41 KWBC 201610 AAD
PNSWSH
Public Information Statement 19-02 Updated
National Weather Service Headquarters Silver Spring MD
1210 PM EDT Fri Oct 20 2023
To:Subscribers:-NOAA Weather Wire Service-Emergency Managers Weather Information Network-NOAAPort
Other NWS Partners, Users and Employees

From:

Stephen W. Bieda III, Ph.D., Chief
Severe, Fire, Public and Winter Weather Services Branch

Subject: Updated: Soliciting Comments until April 30, 2024 on Availabilityof Probabilistic Snow Grids for Select Weather Forecast Offices (WFOs) asan Experimental Element in the National Digital Forecast Database (NDFD)
for the Contiguous United States (CONUS)
Updated to extend comment period through April 30, 2024.
The National Weather Service (NWS) is soliciting comments until April 30,
2024 on providing experimental Probabilistic Snow Grids for select CONUSWFOs in the NWS NDFD. The experimental period has been extended throughthe 2023-2024 winter season. No changes are being made to the product forthis upcoming season.
The grids show the 10% and 90% exceedance percentiles, representing a Low
End Amount (a 90% chance of higher snowfall) and a High End Amount (a 10%chance of higher snowfall) to complement the existing NWS deterministic
snowfall forecasts (most likely amount). Grids are valid for 24-, 48- and72-hour periods out to 72 hours from 0000 Coordinated Universal Time (UTC)Day 1 beginning with the 2200 UTC issuance. They are valid for 24-, 48and 72-hour periods out to 72 hours from 1200 UTC Day 1 beginning with the1100 UTC issuance. As with deterministic snowfall forecasts in NDFD, theProbabilistic Snow Grids are updated every 30 minutes.
More details on the Experimental Probabilistic Snow Grids, including thefull list of participating offices, technical description, and scientificbasis are available in the Product Description Document:
https://nsdesk.servicenowservices.com/api/g_noa/nwspc/res2/a45f05731be5f99
0135feb9ce54bcb1bThese experimental grids are available from NDFD in the following standard
methods:- Gridded Binary version two (GRIB2) files via Hypertext Transfer Protocol(HTTP) and File Transfer Protocol (FTP)- Extensible Markup Language (XML) via Simple Object Access Protocol(SOAP)- Graphics via Web browser

Users who retrieve NDFD elements in GRIB2 format may need to update theirprocedures and scripts to access the files.
GRIB2 files (via ftp or https):
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.00
1-003/ds.snow24e10.bin
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.00
1-003/ds.snow24e90.bin
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.00
1-003/ds.snow48e10.bin
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.00
1-003/ds.snow48e90.bin
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.00
1-003/ds.snow72e10.bin
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.00
1-003/ds.snow72e90.bin
Grids access in GRIB format:
https://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.conus/VP.
001-003/
Extensible Markup Language (XML) access:https:/digital.mdl.nws.noaa.gov/xml
NDFD Map Viewer:
https://digital.mdl.nws.noaa.gov
Information on accessing and using NDFD elements is available online at:https://vlab.noaa.gov/web/mdl/ndfd
Comments and feedback on the proposal to eventually implement theseexperimental elements at all applicable NWS offices are welcome throughApril 30, 2024.
Survey for comments/feedback on Probabilistic Snow Grids:
https://www.surveymonkey.com/r/ExpProbabilisticNDFDSnowGrids_2023-2024
For general questions regarding NDFD data, please email:nws.ndfd@noaa.gov
For technical questions regarding NDFD data, please contact:
David Ruth
MDL Digital Forecast Services Branch
National Weather Service HeadquartersSilver Spring, MD
david.ruth@noaa.gov

For questions regarding this notice, please contact:
Michael Muccilli
Acting Winter Program Manager
National Weather Service Headquarters
Silver Spring, MD
michael.muccilli@noaa.gov
Eric Guillot
Winter Program Coordinator
National Weather Service Headquarters
Silver Spring, MD
eric.guillot@noaa.gov
National Public Information Statements are online at:https://www.weather.gov/notification
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