New Met Eireann rainfall radar website

magicbastarder

christ. it's been over 20 years since i studied probability. i've forgotten more than i ever knew.
it took me a few minutes to cop that your reply does not necessarily contradict my (superficial) point.

Lumen

magicbastarder wrote: »

it took me a few minutes to cop that your reply does not necessarily contradict my (superficial) point.

Hmmm, I think it probably does.

magicbastarder

anyway, with a 1 in 10 chance of it raining on any one trip, you'll *probably* get rained on once per week*

*assuming you are cycling a spherical blackbody in a vacuum.

cdaly_

Lumen wrote: »

If we take the simple case of a commute one hour each way, with a probability of staying dry of 88%, then the probability of staying dry over one 5-day week is 0.88^10 = 28%. Conversely, the probability of getting wet at least once is 72%.

I'm too stupid to work out the probability for half-hour intervals.

Don't forget that the day to day probability of rain is not independent so the calculations would get more complex. Also, having rain in 1/8 of hours is not evenly distributed. You might get 7 hours of rain (while you're at work), ride in and home dry and see nothing for the rest of the week.

The other thing to note is that the rainfall is measured (these days*) using a tipping bucket rain gauge and, because the collected rain may sit in the bucket waiting for the last drop, that the 0.1mm of rain recorded in a tip may have fallen over multiple hours (as drizzle) or even days (end of a shower one day, start of a shower another).

You could consider dowloading some of the minute data (non-airport) to get into the real nitty gritty of getting rained on...







*pre-automation, a 5-inch manual gauge was used.

tomasrojo

I have rain gear packed into my satchel, which I carry whenever I leave the house -- by foot or bike overwhelmingly. After being rained on a few times, I have to wash the rain gear. I have to wash it every few weeks at a minimum most times of the year, with occasional stretches of a month or two without washing.

So, not very scientific, but I have to take out and wear the rain gear quite often, but not constantly.

So, I agree, you don't have to be quite unlucky to be rained on in an average week in Dublin(*). When I lived in Galway it rained about three or four times as often, I think.

(*)EDIT: Now I think about it, I have cycled or walked more than an hour a day during the week for the past few years. Probably more like 2.5 hours a day. So my exposure is higher than in the half-hour commute case that people usually put forward when arguing that you'd have to be unlucky to be rained on very often on your commute.

magicbastarder

cdaly_ wrote: »

The other thing to note is that the rainfall is measured (these days*) using a tipping bucket rain gauge and, because the collected rain may sit in the bucket waiting for the last drop, that the 0.1mm of rain recorded in a tip may have fallen over multiple hours (as drizzle) or even days (end of a shower one day, start of a shower another).

so the rain fallen will only register when the bucket has reached a certain level, no matter how long that has taken? how do you account for evaporation, if so?

tomasrojo

cdaly_ wrote: »

Don't forget that the day to day probability of rain is not independent so the calculations would get more complex.

I think it rains more often in the early afternoon than in the morning in the winter in Dublin. Maybe not.

tomasrojo

magicbastarder wrote: »

so the rain fallen will only register when the bucket has reached a certain level, no matter how long that has taken? how do you account for evaporation, if so?

I guess so:

The tipping bucket rain gauge is not as accurate as the standard rain gauge because the rainfall may stop before the lever has tipped

https://en.wikipedia.org/wiki/Rain_gauge#Tipping_bucket_rain_gauge

Mr. Grieves

Good analysis here, and there's a tutorial if you want to do some analysis yourself on another post.

https://www.shanelynn.ie/wet-rainy-cyling-commute-in-ireland-with-wunderground-and-python/

tomasrojo

Mr. Grieves wrote: »

Good analysis here, and there's a tutorial if you want to do some analysis yourself on another post.

https://www.shanelynn.ie/wet-rainy-cyling-commute-in-ireland-with-wunderground-and-python/

My estimate of Galway being 3-4 times wetter than Dublin is confirmed, to my great surprise. (Not surprised it's wetter, just that my guess was very reasonable.)

cdaly_

magicbastarder wrote: »

so the rain fallen will only register when the bucket has reached a certain level, no matter how long that has taken? how do you account for evaporation, if so?

The bucket itself is quite small and is enclosed in a white housing. It's hard to quantify evaporation in that enclosure between things like sunshine warming the housing, wind blowing through (hopefully minimised by the exposure of the instrument) and the humidity in general.

I would say that evaporation losses are fairly low except between showers in summer time but that dual gauges help to offset this as they are unlikely to tip at the same time and so there's a decent chance that one is empty while the other one is waiting for its moment to tip.

tomasrojo wrote: »

I think it rains more often in the early afternoon than in the morning in the winter in Dublin. Maybe not.

I look forward to the results of your study. Data available from Historical data on met.ie

magicbastarder

actually, my next door neighbour was telling us a few years ago that her dad used to be head of met eireann. she was trying to get them to come collect a load of his papers, but was having difficulty getting them to do so. maybe the required data could be in there...

that said, there's a strong chance she's binned the papers if they didn't collect them.

Zen0

I know it’s a minor gripe, but I wish they’d put the latest station reports in the app rather than requiring a click through to the web. I like to check the temperature at Casement before heading out on a club spin; I find it a good indicator of what I should wear.

magicbastarder

you can get similar info at https://www.tiitraffic.ie/weather/ too (though that doesn't address your complaint).

andy69

and you can get data from local weather stations (personal ones, usually installed in someone's garden) which, like my own one, report data live up to wunderground.

There seems to be one there in Rathcoole for example:

https://www.wunderground.com/personal-weather-station/dashboard?ID=IRATHCOO4&cm_ven=localwx_pwsdash

Won't give road temp's like the TII website, but wind speed/chill-factor/direction etc should be all there

TGD

The site asks you to accept cookies but then gives Dublin as the default location each time. With cookies should it not have copped on that I live in the other end of the country after numerous entries?

magicbastarder

a cookie just tells them that you've been on the site before, and what info you may have looked at before. it wouldn't necessarily store location info (until after you've OKed that)
generally, a location lookup is done by geolocating your IP address. your IP address may only resolve to 'ireland', or be registered in dublin (even if you're in cork).

cdaly_

Zen0 wrote: »

I know it’s a minor gripe, but I wish they’d put the latest station reports in the app rather than requiring a click through to the web. I like to check the temperature at Casement before heading out on a club spin; I find it a good indicator of what I should wear.

TGD wrote: »

The site asks you to accept cookies but then gives Dublin as the default location each time. With cookies should it not have copped on that I live in the other end of the country after numerous entries?

Did you give any feedback to Met?

@Zen0: have you looked at the meteogram on the app? Just click on the icon for today's weather and you should get an hour-by-hour forecast for your location.

silverharp

I preferred the old rain radar, colours were more distinctive, the new one is too blue

cdaly_

silverharp wrote: »

I preferred the old rain radar, colours were more distinctive, the new one is too blue

You can see the old one for the moment on archive.met.ie but right now, the old one is bluer than the new.

The rain layer in the new website is semi-transparent so that the map shows through below. That will result is somewhat muted colours.

Zen0

Thanks for all those replies. Some very interesting info sources there. I like the TII one.

@cdaly: yeah, I know you can get the temperature forecast from the meteogram (which I really like by the way) but I'm looking for actual readings rather than forecast ones. Sometimes it's nice to know what the actual temperature is at my nearest weather station, rather than some theoretical temperature calculated in the Matrix.

Zen0

Oooh! The TII site also has traffic cams. Lots of traffic cams!

I love traffic cams. Does that make me an anorak?

cdaly_

Zen0 wrote: »

@cdaly: yeah, I know you can get the temperature forecast from the meteogram (which I really like by the way) but I'm looking for actual readings rather than forecast ones. Sometimes it's nice to know what the actual temperature is at my nearest weather station, rather than some theoretical temperature calculated in the Matrix.

The 'Current Conditions' bit of the app gives you the actual obs for a station situated in whatever county you're looking at. Mind you, this gives Knock Airport instead of Mount Dillon for Co. Roscommon. IIRC, this is the same behaviour as the old website though the old app used to allow you to select a station from a list.