Author Topic: Will it rain?  (Read 882 times)

quixoticgeek

  • Mostly Harmless
Will it rain?
« on: December 19, 2019, 11:31:17 am »


What are people's preferred sources for weather forecasts?

In .nl Buienradar is pretty good for very short term stuff, but it seems to be a bit erratic outside of .nl.

Windy provides a nice visualisation for wind, but doesn't seem to be much use for temp/rain.

yr.no no longer seems to have the accuracy it used to have.

What sources have people found to be reasonably reliable for forecasts 5-14 days out? I'm mainly interested in wind direction, and low temperature.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Will it rain?
« Reply #1 on: December 19, 2019, 11:35:39 am »
Medium range, ECMWF have a good record.

Generally, I look at the jet stream forecast, ecmwf surface pressure forecast, and interpret what that means for where I live. Broadcast forecasts know nothing about the vagaries of where I live, and would be accurate more than half the time if they simply said "mostly like yesterday".

Blodwyn Pig

  • what a nice chap
Re: Will it rain?
« Reply #2 on: December 19, 2019, 11:44:03 am »
BBC is shite.  been saying rain all day today, all week!.. Whats its doing........fecking sun shine !!!!!!!!!!   I didn't do a planned club ride of some distance , today, opting instead to child mind, due to forecast and accumulation of brownie points,  but gutted now.. :demon:

FifeingEejit

  • Not Small
Re: Will it rain?
« Reply #3 on: December 19, 2019, 11:45:01 am »
I'm using Ventusky and Windy.
Can do a suitable interpolation of the model results they visualise myself... (basically I look at the differences between the models and go pessimistic)


It's pishing doon up here.
BBC use Meteogroup now, the met office website is almost always different from the BBC forecast these days which suggests with the switch suggests MeteoGroup aren't as good as interpolating the results of the models in a manner that suits the BBCs target as the Met Office are.


I also note that Meteo have on their website:
Feedback for BBC forecasts
If you have any feedback about weather forecasts from the BBC, please contact the BBC directly via the following link: http://www.bbc.co.uk/contact

So... that's going well then...

bludger

  • Randonneur and bargain hunter
Re: Will it rain?
« Reply #4 on: December 19, 2019, 11:48:14 am »
I don't know what the BBC's deal is but their forecasts have been shite as BP says. I go straight to the met office app which gives a wildly different forecast which is much better.

I use weatherbagel for guesstimating what my experience will be like on a ride.
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Re: Will it rain?
« Reply #5 on: December 19, 2019, 11:55:28 am »
I walk over to our meteorologists desk and ask him.....

He does say BBC is entirely automated and, therefore, really crap.

Re: Will it rain?
« Reply #6 on: December 19, 2019, 12:04:16 pm »
accurate weather forecasting is more than a bit tricky. A few years ago I attended a fascinating  lecture given by the head of the Met Office who explained the way they use extant data and computer models to make forecasts and to assign them levels of confidence. 

 Turns out that quite small variations in the 'present data'  (i.e. from live weather monitoring stations) can make large differences to the output from a computer model.  So one of the things they do is  they run the model many times over, each time with small variations in the input parameters.  They then compare the predictions of these various models. If the predictions are always the same then they have a confident forecast. However if they vary wildly then the confidence level is much smaller.   

Needless to say the predictions vary more as you predict further ahead.  This means that only rarely can you assign a very high confidence level for a forecast (say) even a week ahead of time.

The proud boast of the modellers is that their predictions a week ahead are as good now as their predictions for tomorrow were a few decades ago. This sounds great until you realise that this means 'around 50%, probably worse than that'.

This is worth a look

https://weather.slimyhorror.com/

but the priorities used to judge accuracy are not the same as yours. The links from that page are interesting too.

IIRC the BBC don't use the Met Office any more. Duh. Hence their forecasts have been a bit shit for a little while now.

[ they said they were looking to change in 2015, and because they couldn't get anything that worked for them, ended up extending the contract with the Met Office until march 2018.  Since then it has been 'meteogroup'.  ]

cheers

zigzag

  • unfuckwithable
Re: Will it rain?
« Reply #7 on: December 19, 2019, 12:20:07 pm »
i use yr.no for 2-3 day forecast which i find accurate enough (80-90%), don't really trust any longer term forecasts. just be prepared for whatever is likely to happen.

quixoticgeek

  • Mostly Harmless
Re: Will it rain?
« Reply #8 on: December 19, 2019, 12:31:11 pm »
i use yr.no for 2-3 day forecast which i find accurate enough (80-90%), don't really trust any longer term forecasts. just be prepared for whatever is likely to happen.

Yeah, the problem with a route that spans 11 degrees of latitude, in December, is the temperature conditions are gonna vary a lot. I need to work out which tyres to choose. I could just fit the winters' for the whole thing, but if the ice is only a slight risk in the last 100km, that's a lot of extra drag for the warm days. I could carry them the whole way just in case, but that's a lot of extra weight just on the off chance. Being prepared for everything on a trip like this is heavy.

Hence good quality weather forecasting is important.

Buienradar is currently saying the area I'm gonna hit will be +2°C when I'm there, while yr.no says -1 - -2°C...

J

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Jaded

  • The Codfather
  • Formerly known as Jaded
Re: Will it rain?
« Reply #9 on: December 19, 2019, 12:54:53 pm »
Yes, the BBC 'saved' money by going to Meteogroup.

As others have said, for a proper forecast, usr the Met Office app. for something that will tell you if it is raining now, use the meteogroup app.

Edited for silly typoingness
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FifeingEejit

  • Not Small
Re: Will it rain?
« Reply #10 on: December 19, 2019, 01:24:06 pm »
Yes, the BBC 'saved' money by gong too Meteogroup.

As others have said, for a proper forecast, usr the Met Office app. for something that will tell you if it is raining now, use the meteogroup app.

I find to be more accurate for nowcasts

quixoticgeek

  • Mostly Harmless
Re: Will it rain?
« Reply #11 on: December 19, 2019, 01:25:20 pm »

I find to be more accurate for nowcasts

Doesn't help me on working out if there will be ice around the Walensee on the 29th...

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Will it rain?
« Reply #12 on: December 19, 2019, 01:28:31 pm »
It's the window with frosted glass

Re: Will it rain?
« Reply #13 on: December 19, 2019, 01:56:15 pm »
Medium range, ECMWF have a good record.

Generally, I look at the jet stream forecast, ecmwf surface pressure forecast, and interpret what that means for where I live. Broadcast forecasts know nothing about the vagaries of where I live, and would be accurate more than half the time if they simply said "mostly like yesterday".

Yes, ECMWF is supposed to be much more accurate than GFS.  On Windy.com one can compare these and others...
Destroying rainforest for economic gain is like burning a Renaissance painting to cook a meal.  EOW.

Re: Will it rain?
« Reply #14 on: December 19, 2019, 03:04:23 pm »
often lost.

Re: Will it rain?
« Reply #15 on: December 19, 2019, 03:14:22 pm »
You got a window? Open it :)

The BBC is overly cautious. It predicts rain more than other apps on the basis most people avoid doing things in the rain over getting a decent jacket. I've given up cancelling stuff because of the BBC app.

I like the radar view on the Met Office app, it seems about as accurate as it's possible to get and gives a better indication of light or heavy rain instead of one or two drops under a cloud.
Duct tape is magic and should be worshipped

Re: Will it rain?
« Reply #16 on: December 19, 2019, 03:21:37 pm »
raintoday.co.uk is my goto site for working out whether there's rain happening over the next couple of hours, and how long for. Most useful when a front comes through as you get a good visual of what's happening.

Re: Will it rain?
« Reply #17 on: December 19, 2019, 03:46:39 pm »
The BBC is overly cautious. It predicts rain more than other apps on the basis most people avoid doing things in the rain over getting a decent jacket. I've given up cancelling stuff because of the BBC app.

I find this problem with all forecasts. A prediction of "rain" can mean anything from a little bit of ignorable drizzle to pissing down non stop.

Re: Will it rain?
« Reply #18 on: December 19, 2019, 03:49:42 pm »
doppler radar is brilliant and in most places is easily the best thing to judge whether you are just about to get wet or not in the next hour or two.  However the radar data from various different sources varies and the way it is processed to show rainfall or not is often different too. Hence you can get discrepancies.

This page

http://www.southamptonweather.co.uk/rainradar.php

shows several different radar plots. They are rarely in complete agreement and sometimes there are significant differences between them.

cheers

Basil

  • Um....err......oh bugger!
  • Help me!
Re: Will it rain?
« Reply #19 on: December 19, 2019, 04:05:28 pm »
raintoday.co.uk is my goto site for working out whether there's rain happening over the next couple of hours, and how long for. Most useful when a front comes through as you get a good visual of what's happening.

This was very useful in Birmingham, as I could usually work out how long before it rained or stopped raining and then decide whether to leave work early, or whether it was worth staying later.  Or indeed if it wasn't going to stop or start, in which case it didn't matter.
It's different here.  You can see the rain heading west over our location, but the trailing edge just never gets any closer.  Also you often can't see it coming as rain has a tendency to pop up out of nowhere.
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Tim Hall

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Re: Will it rain?
« Reply #20 on: December 19, 2019, 06:42:27 pm »
From "How to be an Alien" by George Mikes:
Quote
English society  is  a class  society,  strictly  organized  almost  on corporative lines. If you doubt this, listen to the weather forecasts. There is  always  a  different  weather  forecast  for  farmers.  You  often  hear statements like this  on the radio:  'To-morrow it will be cold, cloudy  and foggy;  long  periods  of  rain  will be interrupted  by  short  periods  of showers.' And then: 'Weather forecast for farmers. It will be fair and warm, many hours of sunshine.' You must not forget that the farmers do grand  work of national importance and deserve better weather.

So go for the farmers' forecast.
There are two ways you can get exercise out of a bicycle: you can
"overhaul" it, or you can ride it.  (Jerome K Jerome)

Re: Will it rain?
« Reply #21 on: December 19, 2019, 09:24:16 pm »
From "How to be an Alien" by George Mikes:
Quote
English society  is  a class  society,  strictly  organized  almost  on corporative lines. If you doubt this, listen to the weather forecasts. There is  always  a  different  weather  forecast  for  farmers.  You  often  hear statements like this  on the radio:  'To-morrow it will be cold, cloudy  and foggy;  long  periods  of  rain  will be interrupted  by  short  periods  of showers.' And then: 'Weather forecast for farmers. It will be fair and warm, many hours of sunshine.' You must not forget that the farmers do grand  work of national importance and deserve better weather.

So go for the farmers' forecast.

This ^^^  but in France at least it is still only good for 24hours. All other forecasting for where I live is generally unreliable or downright wrong (with occasional exceptions to make sure even the paranoiacs can't predict what's going to happen).

The best way of predicting weather is by learning to watch (and watch out for) the wildlife. When the "grues" go over you know that winter or spring is coming (dependent on which direction they're flying)

Re: Will it rain?
« Reply #22 on: December 19, 2019, 09:47:03 pm »
I use the BBC forecast but not in the last 2 months because I haven't been cycling, I don't expect the accuracy to have changed. I only check in the morning for the rest of the day.

Obviously, rain is very localised, esp showers. The trick to to look at the map showing the cloud and rain cover, ignore the general forecast at the top of the page which a summary for the whole region, eg for London it will cover pretty much the whole the South East.

The map only shows the forecast in 4 hour blocks but I found generally to be accurate,most of the time.