Data Quality

The more I look at the charts, I wonder how the temperature data accuracy is compiled?
http://weather.gladstonefamily.net/site/C9670?tile=10;days=3#Data

Why the red 4+ degree variance?

The site is being compared with the list of sites below. In my area, sometimes one or more of those sites is way off, which effects the rating. However, the key thing to look for is the MADIS rating, not the big check/X/? (don’t recall seeing an ? before). The thumbs up or down is more accurate.

You have 2 thumbs up for all of your readings so you should be fine.

Ref from the page:

The 'MADIS rating' reports on the percentage of observations that pass the MADIS checks. [b]You should aim for two thumbs up![/b]

My report typically has an X for Dewpoint because one of the below compare sites is way way off… (not at the moment now though).

http://weather.gladstonefamily.net/site/C2582?tile=10;days=7#Data

Haven’t looked at this for some time… Wind Vector is new.

Your charts look more flat line.
Is CWOP telling me that my actual temperature rises and falls 5 degrees every 10 minutes and my station is not reporting it?

I wouldn’t worry so much about what the MADIS rating is. I had that problem with the MADIS rating being off about 18 months ago and I obsessed over it. I finally realized that I was making myself nuts over it and quit worrying about it.

It resolved itself within about a month.

And the red oscillating line is the comparison stations…not you. The blue line should be you.

There’s clearly a problem with one or more of the stations used in the analysis of your station’s temp, the graph should look like the baro one. I suggest you do as the page says “You can signup on the wxqc mailing list and post information about this situation there”.

I have the same issue, except with humidity. I don’t believe there are other stations closer than 5 or so miles to me which would make their comparison a tad difficult. I can “adjust” my settings within WD to bring it more in line with what the others have but…

I dont like how they compare your readings to others either. Just because other stations are 5 degrees different than yours, it doesnt make it wrong. They dont account for hills, or mountains in between stations. I get a bad percentage from them too on certin days. I’m close to taking my CWOP stats off of my page.

CWOP is stating that my readings are not within an acceptable error range.
If this is the case, is my data worth sending if it’s that far off?

That whole QA thing is auto generated by computer, I think you need to communicate with them and point out the problems with the analysis.

I just emailed them… I’ll see what they say.

I have that same problem too few station to compare too and some of the ones they use are anywhere from 60-100 miles away. I just worry about the Madis checks and forget the x’s. Heck I’m 250 feet from salt water so my humidity reading can be anything from 60-90% with no wind. Temps are generally good except sunny days can heat the area up compard to the ligth house they us where they don’t have any trees around them to block air flow.

John

Here’s their response…

Mark,

Your temperature and wind obs look very good (less than 1% QC failure).
Your barometer, however, which shouldn’t be affected by the terrain
is failing 100% of the time with a 2mb bias. Russ can probably help you
adjust your pressure obs to eliminate this bias.

Thanks for sharing your data,

Patty

I dont understand how my barometer can be off If I have it set by NOAA, as of 4:20pm

From NOAA Barometer: 30.24 in
From my station: 30.14 in

Mark, the email mentions a 2 mb discrepancy. 2 mb is only 0.06 in hg, the numbers you quote show your baro 0.1 in hg low compared to NOAA which (allowing for rounding and unless I’m missing something) seems to be right in line with the discrepancy in Patty’s email.

I adjusted my barometer again to NOAA’s for my area. I’ll keep an eye on it to make sure it stays close.

I just got another email from them. There comparing my barometer readings to the closet airport which is about 30 miles South West of me. The elevation of that airport is 32 feet. My elevation is almost 800 feet. How can they compare mine to that? I dont understand unless Im missing something here.

Because both barometer readings are adjusted (for altitude) to the equivalent sea level value.

On a VP, Can you set your elevation on your consol?

On a VP, Can you set your elevation on your consol?

Yes, easiest to do right from WeatherLink!

Maybe thats the issue here then. On a La Crosse station you cant set your elevation.

Yeah, but still not so sure cwop is the be all and end all! You may be able to find a neighbor or friend in the area that has a simple barometer to confirm (or not) your readings.