Cumulus Support

After a yeasr I've now got a bloke round to put my wind recorders up on the roof on a pole. I'm now at least 10 metres up and 2 metres above any obstructions.

My question is...and this is why I'm feeling stupid...on the wind direction there are little letters referring to the points of the compass. Which way should I be reading these letters when installing. If I'm looking at the letter N should that be on the south side? or should the N be on the north side? See what I mean? Stupid and confused. I think I've put the N on the south side which means my wind direction is wrong.

Help to clarify would be great! Thanks

The N needs to be facing north (i.e. on the north side) - true north rather than magnetic.

Steve has you going in the right direction I'm sure, I'm not familiar with the station myself. Here's a link to a manual that might help things, too. http://wiki.sandaysoft.com/a/Fineoffset_manual

I can understand the confusion on this, though. If your trying to sight the anemometer to north then your eyes are probably situated on the "south" side of the anemometer looking north and the "N" is hidden on the opposite side, eh? Since the "S" is located 180-degrees from the "N" I would just use it to get aligned with true north.

You will need your declination to figure out where true north is for your location. My location has roughly negative 3 degrees of declination. It appears the UK has roughly a negative 2 degrees of declination. Here is a map that will help out on that: http://magnetic-declination.com/ . With a regular compass (like a $10 Silva or something) these small amounts of correction are rather difficult to make by eye-balling things...we just have to get close and call it "good", I suppose. My wind directions have been pretty much in line with the "official" airport data and other PWS in the area so I guess I got it close enough.

Best wishes.

Well, yes, I think that I would be looking at an "S" on the anemometer, so I would be looking North, so the "N" is hidden from me...on the North side. As for accuracy, I got my smart phone out (The very lovely Google Nexus 5...lol) downloaded a compass with a stack of good reviews from geeks who care and pretty much got it facing as close to North as guess work would have it! However, it wasn't me that put it there, it was the aerial man. I had marked N with a strip of sticky tape and I think he face the N on the North side.

Looking at the results from WOW on the Met office, my station does seem to be recording similar results as the others in my area. However, my gut feeling and feeling the gusting wind in my back garden, it felt like the wind was coming FROM the south, therefore "Wind Direction" should record North...is that right? Or in Meteorlogical speak, Direction is from...still a bit confused! But it is very late and its been a long old day.

it felt like the wind was coming FROM the south, therefore "Wind Direction" should record North...is that right? Or in Meteorlogical speak, Direction is from...

If the wind is coming from the south then it is "recorded" as wind direction South (south winds blow north, west winds blow east, etc.). I have recently seen winds gauges/dials showing an arrow across the compass with the feather at the direction the wind is coming from and the point at the direction the wind is going. This does describe the flow of wind accurately.

Paul

The wind is approximately southerly over most of the UK at the moment, so the console and Cumulus should be displaying approximately south, not north. So it sounds like you have the wind vane the right way round.

Thanks everyone for that. I was looking at Boscombe Down last night and they had their wind direction wrong...just like me lol so I'm happy with my set up. Sadly, the wind has really messed up my rain measurements, I think its being buffeted about a bit. I've had to move it until I can properly secure it.

Thanks again

Hi,

The reason is that a "traditional" mechanical wind vane (or weather cock) must always face into the wind, because the air pushes the (larger) "tail feathers" downwind. So automatic/electronic weather stations generally replicate this.

However, to add to the confusion, the "arrows" in the BBC TV weather maps / website point in the direction that the air is actually moving (e.g. North in a Southerly wind) !

Cheers, Alan.