[wxqc] FW: Alert:Centerville, KS

[George Kellerman]

Thought this might be interesting to this list

Public Information Statement
807 am EDT Tue Sep 12 2006
public information statement
National Weather Service Kansas City/Pleasant Hill MO
700 am CDT Tue sept 12 2006

The following change has no direct impact on NOAA weather wire 
service subscribers.

The automated surface observing system/ASOS/product improvement 
program will deploy a replacement wind sensor at the downtown Kansas 
City Airport/mkc...Wednesday September 13, 2006. The new sensor will 
report wind information using the 3-second world meteorological 
organization/WMO/gust Standard.

The current ASOS wind sensor/Belfort 2000/uses rotating cups to 
measure wind speed and a vane to measure wind direction. Over a 
two-minute period...ASOS uses 24 five-second averages to determine 
the two-minute average wind speed and direction. Every minute ASOS 
stores the highest five-second average speed for the past 
minute...along with its direction...in the 12-hour archive for 
additional processing. The highest speed value is used to determine 
if a gust and/or a peak wind remark will be reported.

The new ASOS wind sensor/vaisala 425nws/is a sonic anemometer. It is 
known as the ice free wind/ifw/sensor. It has no moving parts and 
will operate better in winter weather condtions. As with the Belfort 
sensor...over a two-minute period...ASOS uses 24 five-second 
averages to determine the two-minute average wind speed and 
direction. But the highest three-second running average speed is 
stored for gust and peak wind processing.

While there will be little difference in two-minute average 
windspeed and reporting...the changes in gust and peak wind 
reporting may be significant. We can expect to see more gusts and 
peak winds reported with the new sensor. The mass of the moving 
parts in existing sensors limits responsiveness. The new sensor 
will be more responsive to short term gusts.

If you have any questions about this change...please contact:

George Amis
observing program Leader
WFO Pleasant Hill Missouri
816-540-5147


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