WATSON W-8681 WINDCHILL

[mendosino]

Implore one's help, Shall I station WATSON W- 8681. Programme CUMULUS portrayals lower WINDCHILL, than embodies station. Where's problem? Thank you
onderka.bretislav@seznam.cz

[steve]

You probably have Cumulus set to calculate the wind chill (in the station settings), and it uses a slightly different formula. What are the actual values that the station and Cumulus are showing?

[steve]

I've realised that Cumulus always calculates wind chill for Fine Offset stations, because they don't supply it. And on my console, there doesn't seem to be a way to display wind chill anyway. Does anyone else with a Fine Offset station have a console which shows wind chill?

[6719jason]

I think from what I can remember, if you quickly shutdown Cumulus and Fire Up Easy Weather (Awful Software), You can setup what is displayed on the Console using the Station Setup Screen. I am sure you can select 'Wind Chill' in the Outside Temperature Column.

Jason

[dane]

My Watson "manual" says that pressing the outdoor temperature will rotate thru outdoor temperature, wind chill and dew point.
(just checked - it does )
Ib

[steve]

Oh yes, my manual says the same, I couldn't find that earlier

How does the wind chill value displayed by the station compare to the value calculated by Cumulus (if you have any wind)? We have insufficient wind here at the moment, unusually, so I can't check mine.

[dane]

I had my station set to "calculated by Cumulus" -probably based on your advice in the Help file Have now turned it off and will report what difference I see (I wouldn't know how to compare as I cannot record both).
Ib

[steve]

Thanks. As it happens, for Fine Offset it doesn't (shouldn't) make any difference, as Cumulus always has to calculate it anyway (and it always uses any calibration settings, either way).

[dane]

Are you saying that removing the checkmark will make no difference? - because Cumulus does the calculation anyway?
(I know why I activated it: I have a calibration factor for wind speed, so I thought it a good idea to let Cumulus do the maths for me).
Ib

[steve]

Yes. Fine Offset stations don't make the wind chill available to Cumulus, so it has to calculate it anyway. It does use different path though the code to do it, but it uses the same algorithm, and it uses the calibration settings in both cases. So the option should make no difference, in theory.

[dane]

There's a difference. Just did a quick comparison.
Cumulus (without checkmark) remained at 1.9 degrees, while the console said: 0.5, 0.8 2.9, 3.9, 3.4 1.5, 2.8, 3,4 over the same period.
The station seems to recalculate and report a new wind chill value every 48 secs.
Ib

[steve]

Those values from the station vary rather too much over a short period for my liking. I wonder if the station is using the gust value to calculate the wind chill... Cumulus uses the 'speed'. Do you have any calibration set for wind or temp?

[dane]

Calibration: for temp: none. For wind: 1.6
Ib

[steve]

That makes direct comparison a bit harder, then

We have a little bit of a breeze here now, so I'll do some comparisons here.

[steve]

From my tests, it looks like the console does use the 'speed', the same as Cumulus. The figures both tracked up and down in a similar way, depending on the speed, with the console consistently about 1.5 degres lower than Cumulus.

I think the simple answer is that the console uses a different algorithm to Cumulus.

I'll do some more tests tomorrow when we expect to get higher wind speeds. Many thanks for your help, Ib.