MetService 'Your Weather' can actually be useful!

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TLD

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#162212 2-Feb-2015 11:55

Can't find the old Your Weather thread, and it is probably locked by now. Anyway, at long last we are having a tiny bit of rain down here, and checking the local Your Weather map demonstrated that it can actually be useful. That's me center top at Rapaura, and I can see that in the last few minutes (depending on how the individual weather stations have their refresh rate set) the rain is much lighter in Blenheim, and not raining at all out at Renwick.

I suppose I have already underlined the weakness in this concept regards the unknown refresh rates, but it's a guide at least.

Hmmm... just reloaded the web page and the rain figures have significantly changed in the time it has taken me to start this thread. Another idea bites the dust.

Trevor Dennis
Rapaura (near Blenheim)

luckysurprise

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#1229022 2-Feb-2015 21:29

Not on Your Weather but a Computer Repair firm 300m from where I live have their weather station online which gives much more accurate depiction of what is happening where I live rather than the "official" station out at the airport on the coast 10km away. Much more detailed too with humidity, wind chill, barometric pressure etc. And updated every 5 minutes too.

DS248

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#1230334 3-Feb-2015 11:13

Total rain in last 24 hrs or similar would be more useful than current rate (mm/hr)

JonnyCam

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#1230561 3-Feb-2015 14:35

I've just looked up my station on the WOW site, and the last upload was 2pm (1am GMT)
I'll look at the logs on my weather station tonight and check how often it uploads.

weewx uploads from my station to weather underground every 20 seconds, even thought the data is only collected very 40 seconds.
I got a cheap station from 1-day, $90, and have it plugged into a raspberry pi running weewx for the receiving & uploading (to both WoW and weather underground)

Just noticed that wow was not set to receive my rainfall. The site is much slower & cumbersome than WU.

http://www.wunderground.com/personal-weather-station/dashboard?ID=IWELLING184

vs

http://wow.metoffice.gov.uk/weather/view?reportId=13880002&siteID=905246001

edit: Is this the same Renwick site?
Looks like a heap of rain today (127mm in 2 hours from 12:35pm to 2:35)

http://www.wunderground.com/personal-weather-station/dashboard?ID=IMARLBOR10

TLD

902 posts

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#1230564 3-Feb-2015 14:38

DS248: Total rain in last 24 hrs or similar would be more useful than current rate (mm/hr)

I suspect that Met Service does have access to that information from WOW so it would be doable, and certainly useful. What we are looking at here appears to demonstrate significant differences in rainfall over a relatively small area. In my example map above, all six monitor sites could be described as being in the central Wairau plain, so it's not even as if geographical features are in play — not to any great extent that is.

The official Met Service site at the Woodburne base/Blenheim airport, nearly always has higher wind speeds that the other near monitor locations. I had assumed that was because the gauge was mounted high on the control tower. I now know the site is at ground level across the back of the airport, so that theory fails. It could be the large area of flat land around the site. Cape Campbell tends to show even higher wind speeds, and that site is also very exposed.

ISTR some controversy a few years back over who has the most sunshine hours in NZ. I know there was an issue with Taranaki over instrument calibration, but the one I am struggling to remember was when a town suddenly started doing much better after relocating their monitor site. I guess NZ really is the tops when it comes to micro-climates! It has always amused me that Alexandra is both the hottest and coldest place in NZ. There are deep enclosed valleys in Switzaland that have similar extremes of climate.

Trevor Dennis
Rapaura (near Blenheim)

DS248

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#1230668 3-Feb-2015 17:27

Not surprising though that there are large differences in rain rate (or even 24 hr rain) between locations a short distance apart. Just have to look at rain falling from clouds. Not uncommon to see shafts of rain under individual clouds. There have been a number of times when it has been dry at home but heavy rain only a couple of km away (& vice versa, of course).

DS248

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#1230672 3-Feb-2015 17:47

JonnyCam: ...

I got a cheap station from 1-day, $90, and have it plugged into a raspberry pi running weewx for the receiving & uploading (to both WoW and weather underground)

'We' just changed over from Cumulus on my to using WeeWX on a Raspberry Pi (cannot claim any personal credit for this. One of my sons set it up for me. Of course, just weeks before Pi2 came out :( ). A bit more effort but did not like the idea of running the PC 24/7. WS3083 weather station.

Seems to work fine with WoW (have not bothered with WU yet).

What I would like to do though is capture the output (eg. 5 min readings of temperature, humidity, pressure etc) and save to a NAS or other external storage; eg as a csv file or similar. Have yet to work out where WeeWX stores the data on the Pi or at least how to intercept that info. From a WeeWX database would presumably be best? ie. to recover any data during periods when the external storage is inaccessible.

Would also like to get daily means (temperatures, etc) and totals; eg. rain, radiation (kWhr/m2), etc. Guess may need to do own summation for solar radiation

Any suggestions on how to access the data welcome!

Eitsop

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#1230703 3-Feb-2015 18:32

Hmm sadly I just brought my Raspberry Pi 2 weeks ago as well.. would have liked the PI2

I Will hook in a custom board & temp sensor.. $10 from Aliexpress.. and then run python code to update WOW web data

Be interesting if there were thousand of these.. they could change to heap maps..
Or even better a heat map on time-lapse.. like rain radar..
We could see how temp changes across a city/region over a day.. or extreme weather events

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Trade NZ and US shares and funds with Sharesies (affiliate link).

floydbloke

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#1230706 3-Feb-2015 18:36

DS248:

'We' just changed over from Cumulus on my to using WeeWX on a Raspberry Pi (cannot claim any personal credit for this. One of my sons set it up for me. Of course, just weeks before Pi2 came out :( ). A bit more effort but did not like the idea of running the PC 24/7. WS3083 weather station.

Seems to work fine with WoW (have not bothered with WU yet).

What I would like to do though is capture the output (eg. 5 min readings of temperature, humidity, pressure etc) and save to a NAS or other external storage; eg as a csv file or similar. Have yet to work out where WeeWX stores the data on the Pi or at least how to intercept that info. From a WeeWX database would presumably be best? ie. to recover any data during periods when the external storage is inaccessible.

Would also like to get daily means (temperatures, etc) and totals; eg. rain, radiation (kWhr/m2), etc. Guess may need to do own summation for solar radiation

Any suggestions on how to access the data welcome!

If weewx was installed using the Debian package it will be storing its historical data in a SQLite database.

Was Apache running on the Pi. If so then all your data should be easily accessible via the default html pages.

Easy enough to find out, point your browser to http://<IP_address_of_RPi>/weewx

Did Eric Clapton really think she looked wonderful...or was it after the 15th outfit she tried on and he just wanted to get to the party and get a drink?

JonnyCam

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#1230837 3-Feb-2015 22:28

DS248:
JonnyCam: ...

I got a cheap station from 1-day, $90, and have it plugged into a raspberry pi running weewx for the receiving & uploading (to both WoW and weather underground)

'We' just changed over from Cumulus on my to using WeeWX on a Raspberry Pi (cannot claim any personal credit for this. One of my sons set it up for me. Of course, just weeks before Pi2 came out :( ). A bit more effort but did not like the idea of running the PC 24/7. WS3083 weather station.

Seems to work fine with WoW (have not bothered with WU yet).

What I would like to do though is capture the output (eg. 5 min readings of temperature, humidity, pressure etc) and save to a NAS or other external storage; eg as a csv file or similar. Have yet to work out where WeeWX stores the data on the Pi or at least how to intercept that info. From a WeeWX database would presumably be best? ie. to recover any data during periods when the external storage is inaccessible.

Would also like to get daily means (temperatures, etc) and totals; eg. rain, radiation (kWhr/m2), etc. Guess may need to do own summation for solar radiation

Any suggestions on how to access the data welcome!

You can tell weewx to ftp at regular intervals, so if your nas has an ftp server that's easy.

I found weewx so easy to set up, as the debian install default did most of the configuration. Most of my frustrations came from using vi to do the config editing.

You can also download the info from weather underground.

floydbloke

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#1231269 4-Feb-2015 17:52

JonnyCam:... Most of my frustrations came from using vi to do the config editing.
...

I find nano a lot more user-friendly.

Did Eric Clapton really think she looked wonderful...or was it after the 15th outfit she tried on and he just wanted to get to the party and get a drink?

DS248

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#1231271 4-Feb-2015 17:55

NAS does have an ftp server but at least for the present have found a simple way to back up copies of the sdb file, albeit manually. Found that we can access R.Pi from a Windows PC using FileZilla ftp access. Scheduled backup would of course be better. Had no success trying to access WeeWX on the Pi using a web browser.

Would be interesting to know how long WeeWx stores individual readings for before over-writing old data (if it does). Currently has 17.4days readings @ 5 min intervals, giving a ~1MB sdb file (around 200MB for 10 yrs data?). Can live with that.

A few other questions but they will have to wait until have more time!

==
The wireless link between the outside sensors & console unit seems to be a bit flakey (WS3083). Lost connection a couple of times yesterday for a few minutes and today for over 2 hrs. Recovered today only after 'de-powering' the console unit and re-starting :(.

Maybe need to replace batteries in the outside unit(?). Has only been operating for ~5weeks or so, though was bought almost a year ago.

grant_k

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#1231306 4-Feb-2015 18:34

DS248: The wireless link between the outside sensors & console unit seems to be a bit flakey (WS3083). Lost connection a couple of times yesterday for a few minutes and today for over 2 hrs. Recovered today only after 'de-powering' the console unit and re-starting :(.

Maybe need to replace batteries in the outside unit(?). Has only been operating for ~5weeks or so, though was bought almost a year ago.

This sort of behaviour with my original Oregon Scientific, then LaCrosse then Honeywell 'cheap and cheerful' weather stations was what finally convinced me to buy a Davis. Now I have solar panels on all but one outstation and their batteries have lasted for over 3 years now. The one remaining outstation with no solar gives me a 'Low Battery' warning on the console several days before it expires. That one lasts around 6 months between battery replacements, but at some point I might convert it to solar as well.

DS248

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#1231385 4-Feb-2015 21:34

My eyes were initially tempted by a Vaisala WXT520(!) but ultimately decided I could not justify that for a 'hobby' interest. Be very nice though if could get 'on the cheap'.

grant_k

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#1231443 4-Feb-2015 23:25

DS248: My eyes were initially tempted by a Vaisala WXT520(!) but ultimately decided I could not justify that for a 'hobby' interest. Be very nice though if could get 'on the cheap'.

I had a quick look at Vaisala's website and shudder to think how much the WXT520 would cost! Their equipment is very much in the 'Enterprise' space whereas Davis are aimed at the serious hobbyist or 'Semi-Pro' market. If you are able to visit the US and bring a Davis back in your checked baggage as I did, you would have change left over from NZ$1000 for a basic setup. To send the system back using Air Freight would have cost an extra NZ$400 when I last looked, whereas it only cost US$50 for an extra item of baggage.

Sure it's a lot more than $349 or whatever you paid for your WS3083. However, you don't have to look far to see reports of problems with that unit as per this example:

The 2 issue I have is the UV is not reporting high enough. Both my units are the same, they do not get higher than 3. Two other WS3083 units I oversee are the same. Also periodically the console loses its way and I have to remove batteries and reset."

Sounds very similar to what you have experienced. What is the point in having a UV sensor if it won't read higher than 3? My Davis has been reading as high as 15.6 in recent days, and its UV sensor is almost 4 years old now. During that time I've never had to remove the console batteries and reset it, whereas that happened every so often with all of the cheapie weather stations I started with.

DS248

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#1232448 6-Feb-2015 23:42

Do not disagree re Davis etc. The WS3083 (cost ~$250 on TM) was a 2013 Xmas present (decided ~18 mths of my talking about it was enough). Then took almost another year to get it set up of course. It was well down market on what I had been trying to justify to myself but to be honest I have been surprised how well it performs. As per the attached image, night temperature readings from even the cheap stations seem surprisingly accurate (3 Met Office stations circled in Pink, ours is 3rd to top). Has been similar most of the time at night and in cloudy conditions. Main problem is of course direct sunlight. Clearly the radiation shielding is not adequate. There are home bake solutions for that though no doubt will be a while before I get time & sufficiently motivated to fix that.

Yes, we had wireless drop outs a few times over 2 days and given others experience will no doubt get more. But no problems today (fingers crossed). That said, given the construction, I am not confident it will survive a severe gale. Then may be time to consider other options.