Cloud height as reported by WD

[oldun]

Yes I have set up the station's height in WD and yes I also calculated the cloud height as reported, my point should be that it is not much use reporting "cloud Base" on ones web site when the reality can not be even close, it is still wall to wall blue out there, I guess that short of having a LIDAR height finder in one's yard there is nothing one can do.
Thanks for the input,
Robert

[Weather Display]

Note just because a cloud height is reported, does not mean there is clouds to be seen....
if and when the clouds form, i.e like in the afternoon from heat build up, then that will be a good indication of the height they will form at, but you have to have accurate dew point reading in the first place, which your weather station, the WM918, is not known to be good at

[oldun]

Thanks Brian,
Do you have any data on the inaccuracies you mention for the wm918 station I presume it is not something nice and easy like a linear offset which could be corrected, I imagine that the errors are unit random.
Do you happen to know how often and at what times the NZAA Meta at the Auckland airport is updated it seems a bit amateurish in operation!
Robert

[Weather Display]

note that the time stamp on the metar is UTC, and we are daylight saving now...
metars are generaly only updated every hour in alot of cases, and that is certainly the case at auckland airport

nothing amateurish aboput a metar report though
re your humidity reading, you could add a 1 wire humidity sensor to your setup

[oldun]

Thanks Brian,
I just put the jug on for the next coffee hopefully that will improve the eyesight as well as wake the brain up UTC yes......... 
Another question you suggest a 1 wire humidity sensor why would this be More accurate, where does one feed this into the WM918, if not where does one plumb it into the system so that it intergrates into WD.
I also note that the biggest difference in predicted cloud height and that reported by the NZAA Meta is before and just after sunrise when the big differences occur in Temp.,Hum.,and Dew point. I expect that this is where the WM918 falls down on Dew point accuracy.
Robert

[Weather Display]

a 1 wire hum sensor is something that plugs into a spare com port, on the pc, with a 1 wire adaptor, and then you configure WD to use the readings from that...

i think you are worrying too much about cloud height, its not meant to be taken as gospel

[JaxWeather]

Oldun,

I have a La Crosse WS-2310 which is notorious for it's Humidity deficiencies, Only reports 20% - 96% for starters...

So I added a 1-wire Humidity sensor that I got from AAG, though now that Eric at Hobby-Boards has cases I would buy one from Him if I had to replace...

WD Gives you the ability to mix (add 1-wire) sensors and chose what is reported as your main station humidity, so while I run a La Crosse the Humidity comes from a 1-wire sensor, and also my wind speed is also from another 1-wire sensor...

-Bob

[NorCal Dan]

Hmmm, my dewpoint is less than current temp and I am in the clouds...WD shows 1630 ft for cloud level...I am at 1309 ft.  The cloud level should be below my height...going to put my figures in the calculator and see what it shows...hmmm, shows 1636 ft.  Strange.

Webcam http://weather.dcrooks.net/wx6.html

[Weather Display]

so what it means is that the clouds should be 300 feet above you

[NorCal Dan]

Yea, the dewpoint should be higher it seems to me...

[lehautfourneau]

Hi all,
I am sure the cloud height reported in metar's is above ground level (AGL) and NOT above mean sea level (MSL).
I have never seen in a metar, a negative altitude reported as the base for a cloud.
When the computed MSL altitude for cloud height is below the altitude of the station, it simply means the air is saturated. More it's below altitude station, more it's saturated.
In aviation, what imports pilots is to know the altitude above the ground at which they will break out of the clouds.
 have read that in aviation books.
By the way the altitude reported in Client Viewer is AGL. It just substract Ground level value from MSL cloud height value I presume ( so, it's correct in my opinion).
In aviation, height is above ground level and altitude is above Mean Sea level.
Sincerely.
 

[NorCal Dan]

It should be possible to show cloud height from sea level rather than height above the station?  Even so, with the numbers I had it showed the cloud height above my location.  The only way I could see to alter the elevation of the clouds that day was to raise the dewpoint above the current temp, resulting in a negative number in the formula.