[wxqc] Data from CW4204, CW2984, KRAS vs. K5BV (AR105)

[Dave Helms]

Hi Tom,

The analysis assumes that, more often than not, station data are 
generally good  by virtue of having their own professional calibration.  
We know that this is not always true so the analysis is simply a first 
guess and not "truth".  It is very possible for a cluster of stations to 
error in the wrong direction equally thereby influencing the analysis in 
a negative way.  I watch the analysis with one eye and the 
representative ASOS stations with the other (in my area, DCA is as close 
as BWI to me, but I use BWI since its away from the big cities about the 
same distance as my station;  DCA is a poor reference station since its 
in an urban area and next to the tidal Potomac River (warm in the 
winter), so not at all representative of the conditions my weather 
station is situated in.

You are right to ignore the explicit QCMS values it you know the 
analysis is contaminated.  In this case, its better to look at a nearby 
and representative ASOS/AWOS station instead.

Dave
CW0351


Tom Hargrave wrote:

> It appears that the data from CW2984, KRAS vs. K5BV (AR105) would be 
> graded OK if it were not biased by CW4204.  In fact it appears that 
> CW4204 is weighted with more merit than other stations, closer stations.
>
> I do not feel I should make any adjustments as the "standard" is 
> biased by CW4204 with I see should be questioned and likely rejected. 
> BAROMETER
> http://weather.gladstonefamily.net/qchart/AR105?date=20060206&sensor=baro&addnl=AR105&addnl=C2984&addnl=KRAS&addnl=C4204
>
> DEW POINT
> http://weather.gladstonefamily.net/qchart/AR105?date=20060206&sensor=dewp&addnl=AR105&addnl=C2984&addnl=KRAS&addnl=C4204
>
> Further, the algorithms building the "analysis" (standard) line 
> appears to not account for the time shift.  A station 20 miles away 
> vs. others 4 and 7 miles would have events occurring at different times.
>
> What is a fellow to do except ignore the WXQA reports.  I feel that 
> using KRAS, which I would presume has official status, likely 
> maintained to traceable standards is a better measure that the "analysis."
>
> Interesting, reviewing the reports for CW4204, I see it is the only 
> correct station in the area for some intervals.
>
> Tom Hargrave.
>
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