What you see in Gladstonefamily.net should be taken lightly. It isn't the best running analysis site. You know your data. You should have other places to look at your data and see if any anomaly is occurring elsewhere or not. Sometimes strange things show up on Gladstonefamily.net and it isn't yours stations fault.
Also don't take the analysis red line as gospel. It is only as good as your neighbor stations....and even then the site glitches on its own even when neighbors are good.
Ignore the wind analysis as it hasn't been working for almost a year. Who knows when or if it will get fixed.
I recommend that you consider MesoWest for better trusted analysis.
That said
your barometer does not seem to be calibrated for Absolute pressure. There are two parts to the barometer. There is Absolute and there is Relative pressure. Although your Relative pressure may seem right to you on your console and on other online services when you upload to CWOP you need to also be certain that your Absolute pressure is correct for CWOP. Most people ignore their Absolute pressure. When you upload to CWOP the software (AmbientCWOP.com in your case) uses your Absolute pressure and applies a formula to that value to come up with your Altimeter pressure. If your Absolute value is incorrect then you see the bad results you are experiencing. It doesn't matter that your Relative pressure is correct....because that isn't used for CWOP uploads. Sure you may wonder why doesn't it use that value which you have already set? The answer is because Sea Level Pressure is different than Altimeter pressure (though they are close). CWOP is one of the few sites that requests Altimeter rather than Sea Level Pressure be sent to them. Your weather station does not have a way to calculate Altimeter....this must be done by the CWOP software (AmbientCWOP.com in your case). To calculate this Altimeter value AmbientCWOP needs to use Absolute pressure not Relative pressure. That is why Relative pressure is ignored.
So how do you set your Absolute pressure and what does Absolute pressure mean? Well there is no other direct source that you can use to directly calibrate your Absolute pressure, so it needs to be done by way of reasoning what this value represents. Absolute pressure is the raw pressure of your barometric sensor at your given elevation. The trouble is that your station hardware doesn't have a way to easily give it your elevation. It needs to know your elevation in order for the Absolute pressure to be correct.
There is a 3 way relationship between 3 values....Absolute Pressure, Relative Pressure and your Elevation. If you know any two values then you can deduce via a calculation what the missing last value is. Therefore what is true for all of us is that we know two things....we know what Relative pressure is by way of looking up the local METAR and we know our elevation by way of map survey topo maps. With these two values we can calculate what your Absolute pressure should be at any given moment. But once you set it, it is done and you never need to adjust it again....because your elevation doesn't change...you are permanently at that location...at a given elevation.
So what you have to do is understand the relationship between these 3 things and then use the method that I have posted (in other linked thread below) in order to properly calibrate both your Altimeter and your Relative pressure. Basically to sum all of this up....the difference between your Relative pressure and your Absolute pressure is indicative of your elevation....this difference is static...it never changes. If you properly dial in both Absolute and Relative pressure then you basically have informed your station what your elevation is, even though the station isn't really asking you for your elevation.
It really is a shame that Fine Offset clone stations are so complicated when it comes to this simple matter. If they could have only changed the interface to ask for your elevation and then they did the math and figured out what your Absolute pressure was based on that elevation this would be a simple matter for anyone. But with the services that Fine Offset upload to they only use Relative pressure and so this doesn't affect most users. But here you are attempting to upload to CWOP and if you want to do this properly then you have to go through this added effort.
Please see this other thread for my calibration method to properly set both Absolute and Relative pressure:
https://www.wxforum.net/index.php?topic=39088.0PS - I hear this all the time...people say how their local airport (METAR) is at a different elevation than them. Well that fact does not matter. The whole purpose of Sea Level Pressure equivalence is how meteorologists are able to compare different locations even when they are at different elevations. That is the whole purpose of Sea Level Pressure...it equalizes every location as if everyone was at the same elevation...it basically reports a pressure that is what it would be if you were at sea level. If everyone then compares their sea level pressures then you have equalized everyone and taken elevation out of the picture. I've simplified this concept to get the bigger educational benefit through. There really is a lot more to this...but you have to start somewhere. Bottom line is that it doesn't matter that your local airport (METAR) is at a different elevation. It also doesn't matter how far that METAR is....that does require a bit of extra knowledge to get things right and it deals with understanding isobars. If you want to learn about this advanced method then read that other thread and after you get those basic concepts down you'll see that in there is another link to the isobar post for taking things to the next level.
