It is a lovely sunny morning here in Edinburgh with not a single cloud in sight, let alone any sort of rainfall. Yet for some reason according to weathercast.co.uk (which is part of Meteogroup), there has been 0.2 mm of rain recorded at the botanic gardens in Edinburgh during the hour between 7am and 8am. To me, that can't possibly be real and proper rainfall since there aren't even any clouds around and there also isn't any wind which could have brought in any rain from anywhere else nearby (as is common when we are in a showery air stream). This 'rainfall' can therefore, only have arisen from condensation which might have got into the rain gauges there. This is something which could have happened quite easily because with the cold air which is in place just now, the relative humidity is very high just now (this was 98.5% at the same station during the same hour) which probably means that there is quite a heavy dew around, and possibly even a touch of ground frost. I could see how it would therefore be quite easy for that to run into the rain gauges and produce what is actually a false "rainfall" total.
If anyone else can shed a light as how this might have happened, I will be more than happy to hear about that. Because that is enough to scupper our chances once again of seeing a completely dry day due to the fact that we have an actual rainfall measurement, I will probably now need to redefine what I would refer to as a 'rain' day and since the long-term 1981-2010 averages which are produced by the Met Office go by the number of days where 1 mm or more of rain has fallen, it might actually be better defining a rain day as a day where 1 mm or more has fallen on any day, and that is what I will be doing from now on in order to prevent this kind of scenario from happening again. Anyway, this has produced a change in the current running totals which for the botanic gardens as at 8am this morning using my new definition of a rain day are as follows:
Monthly Total For October: 13.0 mm (Expected), 19.6 mm (Actual)
Number of Rain Days in October so far: 2.1 (Expected), 3 (Actual)
We have now had 25.9% of our average October rainfall and 24.2% of our average number of rain days in October so far, so this month is currently 50.7% wetter than average according to the actual rainfall amounts and 40.6% wetter than average according to the number of rain days.
2017 Autumn Total: 76.7 mm (Expected), 81.6 mm (Actual)
Number of Rain Days so far this autumn: 12.3 (Expected), 16 (Actual)
We have had 40.5% of our average autumn rainfall so far and 47.3% of our average number of rain days for this autumn so far, so this autumn is currently 6.4% wetter than average according to the actual rainfall totals and 29.7% wetter than average according to the number of rain days.
2017 Yearly Total: 518.8 mm (Expected), 587.6 mm (Actual)
We have had 83.4% of our average annual rainfall so far, so this year is currently 13.3% wetter than average.
In due course, I will then be able to report the number of rain days for an entire year, once I have enough available data for that.
EDIT:
Isn't it funny as well, that we can have a scenario which I have described above where rainfall is recorded without any rain actually falling and yet, we get other situations which are more common such as what happened at 5pm on Wednesday when rain does fall to the extent of actually being quite heavy at one point in time, yet with no rainfall actually being recorded from that.
Edited by user
06 October 2017 09:20:46
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Reason: Not specified
The north of Edinburgh, usually always missing out on snow events which occur not just within the rest of Scotland or the UK, but also within the rest of Edinburgh.