Frost/rainfall recordings

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Richard
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Frost/rainfall recordings

Unread post by Richard »

Ive noticed on the Met Service site for Culverden that there's been a number of days where 0.2mm has been recorded as rainfall when there's being frost instead,so by the end of winter these .2 mm will add up to a few extra mil that's not the true rainfall amount or do these not get added in?

Pukaki is also showing a lot of .2mm
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Re: Frost/rainfall recordings

Unread post by Flutterbye »

Happens all over the South Island after a decent frost and yes, it does get added to the rainfall total. A quick add up of the Culverden total would have confirmed it.
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Re: Frost/rainfall recordings

Unread post by Manukau heads obs »

it will be dew build up in the rain gauge
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David
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Re: Frost/rainfall recordings

Unread post by David »

Often happens here too in winter from heavy overnight dews. This morning and yesterday morning my gauge recorded a single 0.2mm tip.
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Re: Frost/rainfall recordings

Unread post by RWood »

For rational analysis of rain day counts, I use a 1.0mm cutoff. I assign a score to the monthly stats for my "local" site and the 1mm count is a contributor.
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Re: Frost/rainfall recordings

Unread post by NZ Thunderstorm Soc »

I used to add dew/frostmelt into my records as 'precipitation' over the winter months, then MT the gauge, but don't really do now.
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Frost/rainfall recordings

Unread post by jamie »

On a foggy morning I can record 0.4 and even 0.6 on a really dense fog with a slight breeze. Think the breeze helps to form droplets on the funnel.
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Re: Frost/rainfall recordings

Unread post by melja »

I think its still relevant to record it as its still moisture and frost when it melts does add a little moisture to grass as does dew and fog.
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Re: Frost/rainfall recordings

Unread post by RWood »

melja wrote:I think its still relevant to record it as its still moisture and frost when it melts does add a little moisture to grass as does dew and fog.
Agree re recording it as moisture - but my rain days value is used as part of a "pleasantness" criterion based on my personal preferences - the fewer the rain days, the better as far as that is concerned. So I only want to count days where there is some chance the rain will actually have some impact on my activities. I'd prefer to have a count that was based only on daylight hours but that's to difficult to obtain, if not impossible.
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Re: Frost/rainfall recordings

Unread post by melja »

Yes i agree on the 1mm cutoff for a rain day count. _b
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