Pressure Wackiness (solved)

What is directly NNW of the Air? Do you have any photos of where the Air is placed?

Gary, keep in mind that I’ve tried a few placements of the unit and regardless of where I’ve had it, the pressure behavior has always been exactly the same. If you recall, I once had it on a table and it was no different then in terms of the pressure tendencies. I can’t begin to imagine any placement I’ve tried could possibly impact the pressure readings as they have…unless the pressure sensing device in this unit works entirely differently than any I’ve ever had in any weather station I’ve ever owned.

My friend’s Air is located somewhere completely different at his house, yet shows the same rapid pressure increases/decreases that mine does. Edit: I just looked at his and his pressure nearly hit 31.00" a short time ago! The actual barometric pressure is about 30:12". Any barometric device I’ve ever owned, going back to when I was taking meteorology, has never been impacted by exposures in any given direction.

At any rate, this is looking in a general NNW direction.


that’s a Davis screen no ?

There is quite some green around, are those peaks at the moment the sun starts to shine on all that green by any chance ?? That could explain the sudden rise (extra evaporation due to sun on leaves till they have dried). Wonder if the wood doesn’t do the same in lessor way.

The screen is good but as you know it should be about 2 meter above cut grass in open air to ventilate properly and away from structures that can radiate heat.

Eric, that’s the WF recommended radiation shield from Ambient. Now I could see the placement impacting humidity & temperature, but barometric pressure…like this? I had it on a table and the response was exactly the same. No, I’m convinced this is something other than placement. If it is, I need to go back to school for meteorology because this defies anything I was ever taught in terms of what impacts barometric pressure.

There is a phenomenon where wind is forced into an area where it can’t easily escape and that will cause a localized pressure increase. This does not look like that happened, plus the wind was low.

I have no other explanation. Hopefully David will come back with news next week.

Now here’s the latest graph from my friend’s Air. Look at these absolutely wild increases. Nearly 31.00"? No placements issues could possibly explain this. I’m not alone in this issue, his is worse. :frowning:


I’m no expert at all…, I looked at all stations around yours and it seems you have some heavy ups and downs lately. But not in such a short period … guess we’ll have to wait what the guru’s find under the hood :thinking:

though it seems to occur day time … could there be a correlation with temp going up and that the air inside the air expands, since for some weird reason the gortex membrane doesn’t allow it to level directly to the outside ??? Like a balloon expanding under heat ???

Yes, I’m hoping tech support comes up with a solution. My friend is out now, but I’d like to get his station # when he returns. Right now this is the best I can do in terms of showing his location. You can clearly show how bizarre his results are:

That looks like his elevation is wrong. What is his station ID?

Eric, I had first suggested a correlation between temperature and the pressure tendencies. It shouldn’t be to this magnitude and you might expect typical diurnal ebbs & flows of pressure with night & day, but I’ve never seen anything like these in the time period they’ve occurred.

But your idea is what struck me first when I saw this behavior.

Gary, I’m not sure and I had asked him about that, but he said he followed the setup directions and the Google location gave him his elevation. As I mentioned above, I have a request in for his location ID when he’s back home.

If you can get his station ID I’d like to check his settings.

I sent him a text, but not sure when he’ll be home.

Here’s one of the tools I use for checking observations I trust in addition to PWS in my area that I’ve learned to trust over time. For those not familiar with this map, you can click on the 2nd tab, observations, and then check which parameters you want displayed. Remember to check ‘Surface Observations’ after you’ve checked your parameters. You’ll get far more accurate info than the average PWS assuming there are locations close to you. Yes, micro climates will obviously alter readings you get, but you can still learn a lot and things like barometric pressure are much less prone to micro climates anyway:

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Are you on Long Island? That wind graph looks suspicious, like a frontal passage or downdraft. Could it be a localized downdraft caused by sinking air over cold land near the warm ocean during this polar vortex cold snap???

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vreihen, yes I’m on LI, but no frontal passage at all. Further, this is weird barometric behavior that occurs every day with my Airs.

@dsj & Gary- My friend’s station ID is 6234 and mine is 6187.

I’m out at a Vietnamese New Year celebration now. I’ll check the settings when I get home.

In looking at my pressure graphs as well as my friends’, I see an interesting pattern. The larger fluctuations, that are not tied to actual documented pressure changes, seem to occur twice a day, in the 7-7:30 am & pm timeframe. They also seem to follow the largest temperature fluctuations. However in looking at a few other stations on Long Island, presumably there for some time, I don’t see that pattern…and that’s a very good thing.

The thought of having the pressure so tied to the temperature, would create wild pressure inaccuracies much like we’re seeing. So for some reason it seems our newer installations are showing that and the older ones are not. This pattern is continuing today with actual barometric pressures steady, yet my original Air increasing, my newer Air ‘rocketing’ and my friend’s increasing too.

Is it just calibration? I’ll be very interested to see what the tech guys come up with.

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perhaps if you calculated the gradient (difference between two neighboring points in the graph) and plot that, it would show better what you mean. There should be a spike at 7 am and 7 pm (download your data, import it in excel, calculate the gradient and plot)