2003-09-24 16:20  - 
Prior to this date and time, wind speed values were being 
encoded into SHEF with the metric unit "meters per hour" 
instead of the english unit "miles per hour".  

This was corrected because values should be encoded into SHEF 
with english units by default.  Metric units are used only if 
the SHEF file header indicates that the measurements are metric.  

The SHEF codes for these corrected values are those that 
have an element code beginning 'US' or 'UP', for example:
   'UPIRMX' 
   'USDRM' 
   'USHRMX'

If you have any questions, please contact me:
Maggie Dunklee
SNOTEL Data Manager
mdunklee@wcc.nrcs.usda.gov