Davis Rain Gauge

[Wx4U]

Last night a pretty good storm moved through the DFW Area. My VP2 registered max wind @ 61mph. This morning I checked the rain totals ( 4": 0.29; Davis: 0.68; LaCrosse: 0.28). All three gauge are within 12' of each other. It appears the high gusty wind caused a flutter effect on the Davis dumping baskets causing a higher reading. Any one with similar experiences?

[SLOweather]

How old is your gauge? Get a lot of rain?

I had an older VP1 where the bucket pivot holes wore, lowering the bucket a little, and the bucket would sometimes attain a stable, level, magnetically balanced state. Every time the wind blew enough, it would rock and click the switch.

T'otherest thing is if you received any close-by lightning and the reed switch contacts have arced. I've seen that in Davis annys and rain gauges both.

[DanS]

Pretty hefty gusts you get around there! wow.  Is there the possibility the mount that the Davis is on shook from the winds, rattling the tippers?

[Ugly Duckling]

Pretty hefty gusts you get around there! wow.  Is there the possibility the mount that the Davis is on shook from the winds, rattling the tippers?

Getting rain when there is none?

Many Happy Weather Changes,

Marci Anna

[Ugly Duckling]

Last night a pretty good storm moved through the DFW Area. My VP2 registered max wind @ 61mph. This morning I checked the rain totals ( 4": 0.29; Davis: 0.68; LaCrosse: 0.28). All three gauge are within 12' of each other. It appears the high gusty wind caused a flutter effect on the Davis dumping baskets causing a higher reading. Any one with similar experiences?

I got one bucket dump when there was no rain.

Many Happy Weather Changes,

Marci Anna

[Wx4U]

The system is just over two years old and mounted on a 4" x 4" post. I just tried shaking it and now checking the display it did not register any rainfall. The guy next door had a tree down on his car.

[DanS]

hmmm, peculiar... If anything got under the buckets to cause them not to lower all the way to rest on their stops you would get increased/higher readings.

[SLOweather]

2 other possibilities:

Have you pulled the rain cone off and looked at the buckets? Spiders sometimes make webs in there. The usual effect is to have less rainfall as the web interferes with bucket tipping. However, I suppose one could cause the tipper to hang in just the right place and act as a spring, similar to the magnetic balance.

Also, is the cable from the gauge firmly plugged in to the ISS? Unplug it and replug it to be sure, and look for water or corrosion on the plug and in the jack.

[Jim18655]

How about bigger funnel collecting more of the gust and air pressure tipping the scales?

[Ugly Duckling]

Could there be a couple pretty lady bugs in there having fun on the see-saw?

Many Happy Weather Changes,

Marci Anna

[dalecoy]

Last night a pretty good storm moved through the DFW Area. My VP2 registered max wind @ 61mph. This morning I checked the rain totals ( 4": 0.29; Davis: 0.68; LaCrosse: 0.28). All three gauge are within 12' of each other. It appears the high gusty wind caused a flutter effect on the Davis dumping baskets causing a higher reading. Any one with similar experiences?

Yes, it's possible for some gusty conditions to tip the mechanism.  I suggest trying:

1.  Look at strip charts or plots of wind gusts and rain, and see if there is an obvious correlation between gusts and tips.  (The resolution depends on archive interval and may not be good enough to tell anything).

2.  Use an eyedropper and slowly drip water into the VP2, to see if you are getting "double readings" (there is a rare condition where one tip of the bucket can produce 2 "clicks" of the reed relay).

3.  Wait for a gentle rain and do the same comparison.

I presume that you've physically checked and cleaned the buckets, made sure the mechanism is properly seated, etc. etc.

[ocala]

How old is your gauge? Get a lot of rain?

I had an older VP1 where the bucket pivot holes wore, lowering the bucket a little, and the bucket would sometimes attain a stable, level, magnetically balanced state. Every time the wind blew enough, it would rock and click the switch.

T'otherest thing is if you received any close-by lightning and the reed switch contacts have arced. I've seen that in Davis annys and rain gauges both.

Chris what happens when the reed switch arcs?

[SLOweather]

The inside of the glass may darken like an incandescent lamp or old vacuum tube, and the contacts get damaged. Then they'll bounce more on a closure. I have an anny that regularly reads really high after a nearby strike. It didn't help that I have I on >100 feet of cable, which no doubt increased the induced EMF.

How old is your gauge? Get a lot of rain?

I had an older VP1 where the bucket pivot holes wore, lowering the bucket a little, and the bucket would sometimes attain a stable, level, magnetically balanced state. Every time the wind blew enough, it would rock and click the switch.

T'otherest thing is if you received any close-by lightning and the reed switch contacts have arced. I've seen that in Davis annys and rain gauges both.

Chris what happens when the reed switch arcs?

[Heirphoto]

My rain gauge registered .18 this afternoon and was at .19 when I got back from a dinner out. it has not rained here for well over a week and that was only a .01 rain. Turns out a leaf from my bamboo grove fell into the collector and as the wind blew the stiff leaf back and forth it rests against the ridge between the spoon flipping it up and down like a seesaw!

My manual gauge had a dozen leaves in it as well as the wind seems to carry them a good ways.

Tony

[Flag]

This design issue with the rain cone feeder is one issue that Davis needs to address sooner than latter. The plastic debris grate is totally useless. 

[hdmax]

Has anyone here ever tried using something other then the plastic grate? I was thinking maybe a thin peace of scratch pad cut to fit.
I do suppose it could reduce the reading by a 100th, and if that were all, it maybe worth it.

[WeatherBeacon]

Has anyone here ever tried using something other then the plastic grate? I was thinking maybe a thin peace of scratch pad cut to fit.
I do suppose it could reduce the reading by a 100th, and if that were all, it maybe worth it.

Here are some ideas (strainers):

http://www.wxforum.net/index.php?topic=1043.0

It's what I use, and it works well (although I place mine inverted inside the cone).

[Skywatch]

This design issue with the rain cone feeder is one issue that Davis needs to address sooner than latter. The plastic debris grate is totally useless. 

I agree, I lost mine a few months ago. Wind blows guilty. Even the small gusts made it move around. The conical structure of the rain gauge helped by producing little wind vortexes. No sence buying another. Now wishing I had glued it in the first place. Then again, how the accuracy would be effected.

What are those things for anyways? I mean the spacing in the grate to the smallish hole where the rain enters the tipping bucket chamber. What can't pass through the grate but can pass through the rain gauge hole? Common sence!

[Aardvark]

I use something like this:

[rhwxman]

I have a Cocorahs type plastic rain gauge next to my tipping bucket type gauges just to keep them honest.  Many things can cause a tipping bucket gauge to drift off calibration.  I hate pine needles!

[Flag]

A rain gauge should be made such (in the first place) to not require something like having to add a sink plumbing strainer  one should not have to do this! This issue is the biggest failure of the davis rain gauge cone design and something that could be easily included in the moulding.

The more people that complain to Davis about this the sooner something might be done about it.     

[dalecoy]

How would you design it?

[wxtech]

One drop of hot melt glue on one leg holds the strainer in place until you pull it off for cleaning.

[neondesert]

This design issue with the rain cone feeder is one issue that Davis needs to address sooner than latter. The plastic debris grate is totally useless. 

I agree, I lost mine a few months ago. Wind blows guilty. Even the small gusts made it move around. The conical structure of the rain gauge helped by producing little wind vortexes. No sence buying another. Now wishing I had glued it in the first place. Then again, how the accuracy would be effected.

What are those things for anyways? I mean the spacing in the grate to the smallish hole where the rain enters the tipping bucket chamber. What can't pass through the grate but can pass through the rain gauge hole? Common sence!

Don't really know how much more you can do to "protect" a tipping bucket gauge from getting debris inside it.  This is an issue even the NWS has to deal with at their ASOS gauges.
They have to clean out their automated gauges (and manual ones for that matter) all the time.  It's just the nature of the beast.

One thing to note, the conical structure of the gauge can also cause swirling water during high rainfall rates.  This swirling action, if not broken up by something like the debris grate, may cause some of the precip catch
to miss the buckets.  Again, mostly an issue at high rainfall rates but another issue that the grate reduces.

Myself?  I do the same thing as wxtech.  A little drop of hot glue goes a long way! 

[wxtech]

And think you for explaining the swirling action.  I talked with Davis and referred to the debris grate as an "anti-vortex" device.  They didn't understand and wouldn't agree on its importance.  The debris grate helps prevent splattering and rain water missing the buckets.  The debris grate in place does increase rain measuring accuracy.