[wxqc] barometer problems

[Keith Miller]

>-----Original Message-----
>From: wxqc-bounces at lists.gladstonefamily.net
[mailto:wxqc-bounces at lists.gladstonefamily.net]On Behalf Of
jdunaway at optonline.net
>Sent: Wednesday, April 09, 2008 11:47 AM
>To: wxqc at lists.gladstonefamily.net
>Subject: Re: [wxqc] barometer problems
>
>

> The closest airport I was able to get weather data from is
> Laguardia in NYC.
>

That would explain the 1-1/2 hour away... :)


> I just did a search on KPOU and found their data. Their
> pressure reading (50 minutes ago) was 30.25, whereas mine
> reads 30.30. Their altitude is 164', whereas mine (verfiied)
> is 1018 feet as I'm up on top of a mountain. Is the .05
> variance enough for the station to fail the MADIS QC checks?
>

If you didn't already find it:
http://weather.noaa.gov/weather/current/KPOU.html

In my experience, this often doesn't update until about 10 or
15 minutes after the observation. Or use the FSL display
linked from the CWOP website.

Barometer has not been stable today, so it's a bad day to be
calibrating a barometer. But you can get an idea by comparing
observations at, as close as possible, the same time. To that,
record your barometer near the top of the hour, and check what
KPOU recorded. Do this numerous times to develop a good idea
of the difference. But wait for a day that the pressure is
very stable before trying to determine a final calibration.

Oh, MADIS expects, and you should be using altimeter pressure
which is corrected to sea level. So altitude doesn't matter.


Keith
--
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http://weather.gladstonefamily.net/site/C5250