[wxqc] Looking for help with Station - Odd shift in analysis

Ted Lum gladstonefamily73.net at tedlum.com
Fri Feb 19 20:53:42 CST 2016

Although that won't answer your question, especially for Canada... the 
actual specifics are not documented and we don't have visibility into 
what is in a set.  If those other stations are in fact sending SLP then 
they will likely invalidate the analysis for that area due to the 
predominance of those abhorrent stations... we have the same problem 
with weatherlink-IP if there's too many of them in one place.

However, I've looked at your station independent of those others are 
there was still a problem at that time. I'd compare it only to known 
reliable data, and the just assume the analysis isn't reliable.

On 2/19/2016 7:25 PM, Randall Collander - NOAA Affiliate wrote:
> The MADIS Quality Control information can be found at:
> https://madis.ncep.noaa.gov/madis_sfc_qc.shtml .
> On Fri, Feb 19, 2016 at 3:34 PM, Chris Miller <c_miller_1 at hotmail.com 
> <mailto:c_miller_1 at hotmail.com>> wrote:
>     Yes I did manage to verify what I was looking at for CYYB.  The
>     link, http://www.starpath.com/barometers/baro_cal.php, has proven
>     to be handy for looking at the government station data to see what
>     it is that they are sending.  It was the stations like CTNK, CWBE
>     and CWMZ which are just sending SLP that I was wondering about.
>     It is too bad the analysis group is not visible.  Mind you, I
>     could do my own I guess. How far is the analysis area?  Are there
>     limits to the stations used to do the analysis?  Or, is there a
>     document you could point me to that would tell me about the
>     process?  I don’t want to burden you with re-explaining the
>     process again if it is already written down somewhere.
>     *From:* Ted Lum <mailto:gladstonefamily73.net at tedlum.com>
>     *Sent:* Thursday, 18 February, 2016 19:13
>     *To:* Chris Miller <mailto:c_miller_1 at hotmail.com> ;
>     wxqc at lists.gladstonefamily.net
>     <mailto:wxqc at lists.gladstonefamily.net>
>     *Subject:* Re: [wxqc] Looking for help with Station - Odd shift in
>     analysis
>     I checked the airport and it definitely is Altimeter. No, you
>     can't see what stations are in the analysis.
>     On 2/18/2016 6:43 PM, Chris Miller wrote:
>>     I had been using my phone as a comparison for a couple of weeks
>>     and every time I checked it seemed to track, however that sample
>>     is small and scattered so may have had the luck of the draw.
>>     Discovering the correction error in WUHU did account for a couple
>>     of mb.  The station does track the nearby stations and has, when
>>     i get one of those artic highs, all seem to gather together
>>     nicely so, crossing fingers, I hope to see the model come back
>>     soon.  Mind you, in another month or so it is libel to shift back
>>     due to the arrival of spring.  I think there are a few SLP
>>     stations from the government side that may shift the model line
>>     average??
>>     Oh!  While I think of it, is it possible to find out what
>>     stations are used for the L3 checks and the model line?  Mostly
>>     curious as to how close they are and such.
>>     *From:* Ted Lum <mailto:gladstonefamily73.net at tedlum.com>
>>     *Sent:* Thursday, 18 February, 2016 07:50
>>     *To:* Chris Miller <mailto:c_miller_1 at hotmail.com> ;
>>     wxqc at lists.gladstonefamily.net
>>     <mailto:wxqc at lists.gladstonefamily.net>
>>     *Subject:* Re: [wxqc] Looking for help with Station - Odd shift
>>     in analysis
>>     No, the MADIS analysis line gets so crazy sometimes since it's so
>>     sensitive to individual samples/readings.
>>     You may actually have a faulty sensor that is drifting. I know
>>     it's not easy to do, but, I'd start by comparing the raw readings
>>     from the station with another local, uncorrected, pressure
>>     sensor. Nothing needs to be calibrated since you're looking at
>>     the delta over time; if they differ by 2mb today, they had better
>>     differ by 2mb 5 days and 10 days from now... if not, you've got a
>>     very fundamental problem.
>>     On 2/18/2016 7:37 AM, Chris Miller wrote:
>>>     Thanks Ted,  I had been playing with the analysis period to
>>>     escape the shifted data when I made corrections.  The best I
>>>     have so far, with a short analysis period of 3 days, is still
>>>     the 4 to 6 mb below the model line.  I was starting to wonder if
>>>     the model has a large fixed period that it has to work through
>>>     before I would see it shift down toward my setting.
>>>     *From:* Ted Lum <mailto:gladstonefamily73.net at tedlum.com>
>>>     *Sent:* Wednesday, 17 February, 2016 16:12
>>>     *To:* wxqc at lists.gladstonefamily.net
>>>     <mailto:wxqc at lists.gladstonefamily.net>
>>>     *Subject:* Re: [wxqc] Looking for help with Station - Odd shift
>>>     in analysis
>>>     The graphs are what they are in terms of date/time, but the
>>>     default analysis period is 28 days. You can select a different
>>>     period from the links at top of the page, or by specifying a
>>>     specific number in the url.
>>>     On 2/17/2016 4:04 PM, Chris Miller wrote:
>>>>     Ok.  I have set the pressure on the PEET station to 23.46 mb
>>>>     over my local surface pressure.  I have let the station run for
>>>>     a while and cross checked the device used to get the local
>>>>     pressure to the station AV065 and CYYB and any measurement
>>>>     error corrected for.  I discovered that WUHU, when set to QNH
>>>>     pressure to CWOP with the altitude of the sensor set to 650
>>>>     feet (643 feet plus sensor height), that there is a correction
>>>>     that gets applied to the sent data that is not visible on the
>>>>     display locally in the software.  It appears that it has a
>>>>     temperature value in the math, if I read the WUHU news group
>>>>     correctly.  I switched back to weather display with no
>>>>     correction value in the software field and no altitude set in
>>>>     the software and so far the data seems to match what is
>>>>     reported to CWOP.
>>>>     I have let the data run for a few days and my setting tracks
>>>>     the output of AV065, CYYB, AR943 and CYWA with the expected
>>>>     stagger due to weather pushing through.  The models for those
>>>>     stations show them to be on, yet my model still shows me as
>>>>     being 4 to 6 mb low.
>>>>     Is there anything else that could be coming from the data
>>>>     supplied that will skew the model so high?
>>>>     Also, is there a long delay, 3 to 6 months for example, before
>>>>     the model would return to track the station after a burst of
>>>>     bad data?
>>>>     (I cropped down the email as it was getting a little long.)
>>>>     My station, model and nearest neighbours
>>>>     http://weather.gladstonefamily.net/qchart/AU770?date=20160217&addnl=AV065&addnl=CYYB&addnl=CYWA&addnl=AR943&Add+to+charts=Add+to+charts&.cgifields=addnl
>>>>     CYYB, its model and same stations
>>>>     http://weather.gladstonefamily.net/qchart/CYYB?date=20160217&addnl=AV065&addnl=AU770&addnl=CYWA&addnl=AR943&Add+to+charts=Add+to+charts&.cgifields=addnl
>>>>     CYWA, its model and same stations
>>>>     http://weather.gladstonefamily.net/qchart/CYwa?date=20160217&addnl=AV065&addnl=CYYB&addnl=AU770&addnl=AR943&Add+to+charts=Add+to+charts&.cgifields=addnl
>>>>     Chris

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