Time to ignore the forecast!

General cycling advice ( NOT technical ! )
drossall
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Re: Time to ignore the forecast!

Postby drossall » 6 Jun 2019, 8:18am

Slightly OT, but I'm always frustrated when weather apps want to use my location. I know what the weather's doing where I am. I want to know what it's doing where I'm going :D

LollyKat
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Re: Time to ignore the forecast!

Postby LollyKat » 6 Jun 2019, 1:26pm

francovendee wrote:My method is, plan to go, look at the forecast, look out of the window and decide. I have been caught out but not often.

We live at the top of a small hill and from upstairs can see for several miles. The weather seen from the north-facing windows is often quite different from that to the south. The wind direction is not always obvious, either.

The main thing is to have good waterproofs. :)

st599_uk
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Re: Time to ignore the forecast!

Postby st599_uk » 6 Jun 2019, 1:31pm

In the UK we mainly have frontal weather. You start to see clouds high in the sky as the warm front approaches. They build and lower. It rains and there's a wind shift as the front passed then it's overcast and possibly drizzles. The next front approaches, it gets darker and rains, then it passed the wind shifts and you've got clear air.

The Met Office are accurate at predicting the formation of the fronts. So the forecast has the correct sequence of weather, it's the timing that is normally out. Sailing, I know there's a front coming from the forecast chart, but if it arrives 3 hours early I know the upper atmosphere wind is a bit faster than predicted.

As for areas: they use grid squares in the prediction. So if it's a 20km square, it only has to rain in one corner for the prediction to be accurate, you could be 25km away in the same square enjoying sunshine.

The BBC use a Swiss firm. (The government forced the BBC to put it out to tender, then expressed outrage that the MetOffice lost).
A novice learning...
“the dreamers of the day are dangerous men, for they may act their dreams with open eyes, to make it possible.”

Mike Sales
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Re: Time to ignore the forecast!

Postby Mike Sales » 6 Jun 2019, 1:36pm

francovendee wrote:My method is, plan to go, look at the forecast, look out of the window and decide. I have been caught out but not often.


Indeed, it would be foolish to rely only on forecasts, observation is another input. When I lived within sight of the hills that input was even more useful.
Edited because of st399's post. I had forgotten to add that a knowledge of weather fronts etc. is an important input too.
Sailors are taught that the swing of SW wind to the NW as a front passes is something to watch out for, in choosing a sheltered anchorage for instance. Could be useful to cyclists too. You might be able to get a tail wind both ways!

PDQ Mobile
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Re: Time to ignore the forecast!

Postby PDQ Mobile » 6 Jun 2019, 1:44pm

I am less scathing about the Met Office.
They try their best to forecast a chaotic and fickle system with local topographical and other local effects thrown in.

However a recent bone of contention is that they have replaced the simple data saving and quick to load "txt only forecast" with one containing interactive maps and invitations to pop in ones location.
A well written txt forecast is all one could wish for in my view.
A 5 day local one and a shot at a longer range prediction, used to be all on one small page.
Just black and white, simple, but now gone.
It is like many other areas of modern life, made overly complicated for no good reason other than the computer buffs need something to do in their offices.

A reasonably reliable five day forecast can be of enormous worth in agriculture. As can warning of frost.

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mjr
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Re: Time to ignore the forecast!

Postby mjr » 6 Jun 2019, 2:05pm

PDQ Mobile wrote:A well written txt forecast is all one could wish for in my view.
A 5 day local one and a shot at a longer range prediction, used to be all on one small page.
Just black and white, simple, but now gone.
It is like many other areas of modern life, made overly complicated for no good reason other than the computer buffs need something to do in their offices.

No, the marketing departments, focus groups and bean-counters take these things away from you because they're judged not worth the cost of maintaining them. The computer buffs put them back for you, on their own time: http://www.tourbybike.co.uk/text-forecast/
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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Mick F
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Re: Time to ignore the forecast!

Postby Mick F » 6 Jun 2019, 2:55pm

st599_uk wrote:The BBC use a Swiss firm. (The government forced the BBC to put it out to tender, then expressed outrage that the MetOffice lost).
This is the issue.
Two sets of offices producing two sets of (different) information.
Mick F. Cornwall

PDQ Mobile
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Re: Time to ignore the forecast!

Postby PDQ Mobile » 6 Jun 2019, 8:09pm

mjr wrote:
PDQ Mobile wrote:A well written txt forecast is all one could wish for in my view.
A 5 day local one and a shot at a longer range prediction, used to be all on one small page.
Just black and white, simple, but now gone.
It is like many other areas of modern life, made overly complicated for no good reason other than the computer buffs need something to do in their offices.

No, the marketing departments, focus groups and bean-counters take these things away from you because they're judged not worth the cost of maintaining them. The computer buffs put them back for you, on their own time: http://www.tourbybike.co.uk/text-forecast/

Fantastic!
I am in your debt.

st599_uk
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Re: Time to ignore the forecast!

Postby st599_uk » 7 Jun 2019, 9:40am

Mick F wrote:
st599_uk wrote:The BBC use a Swiss firm. (The government forced the BBC to put it out to tender, then expressed outrage that the MetOffice lost).
This is the issue.
Two sets of offices producing two sets of (different) information.
That's how ensemble forecasting works. You create an atmospheric model, tune it for local conditions. Some of the inputs are fixed, like terrain, some a variable.

Then you run it a few thousand times with slight changes in the input variables and see what the consensus is like on the output.

The Met office is highly tuned for the UK and worse over large land masses, the ECMWF and GFS are more generic and aren't tuned for local effects.

They also show different things, the BBC show max gust on forecast, GFS show average wind speed...
A novice learning...
“the dreamers of the day are dangerous men, for they may act their dreams with open eyes, to make it possible.”

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mjr
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Re: Time to ignore the forecast!

Postby mjr » 7 Jun 2019, 10:21am

PDQ Mobile wrote:

Fantastic!
I am in your debt.

We're all in khain's debt. viewtopic.php?f=16&t=95846
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.

gbnz
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Re: Time to ignore the forecast!

Postby gbnz » 7 Jun 2019, 7:43pm

gbnz wrote: Just "go and do it"!


A day of heavy, continuous rain from 14.00 onwards, strong, near gale force winds (Met Office). A special mention on last nights Radio 4 about the weather issues.

So popped out on the bike at 07.10, returned 19.13, remained dry all day, gentle breeze hardly worthy of note. As I relaxed in the sunshine next to the River Swale, I wondered if the met office do it purely to take the mick?

PDQ Mobile
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Re: Time to ignore the forecast!

Postby PDQ Mobile » 7 Jun 2019, 8:37pm

Topography!
Though you were lucky I think.
The rain radar does show rain near to Yorkshire, though there does appear to be a drier slot just around there!
It rained most of the day in Wales, though the wind was light.
Different on the West coast of France where lives were lost at sea.

https://www.bbc.co.uk/news/world-europe-48553351

An unseasonably deep depression.

Mike Sales
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Re: Time to ignore the forecast!

Postby Mike Sales » 7 Jun 2019, 8:54pm

PDQ Mobile wrote:Topography!


I grew to expect a head wind to change to a tail wind when returning to Bangor on the A5 from Capel Curig in a South Westerly.
The leg to Ogwen Cottage up the Nant Ffrancon runs more or less West and could be a long drag into a fierce wind. Then the road turns NNW, less than ninety degrees, down the Dyffryn Ogwen. The glorious downhill home could be tailwind assisted!

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John1054
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Re: Time to ignore the forecast!

Postby John1054 » 7 Jun 2019, 10:19pm

gbnz wrote:
gbnz wrote: Just "go and do it"!


So popped out on the bike at 07.10, returned 19.13, remained dry all day, gentle breeze hardly worthy of note. As I relaxed in the sunshine next to the River Swale, I wondered if the met office do it purely to take the mick?
.

Glad that you enjoyed Swaledale, one of my favourite cycling places :D

drossall
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Re: Time to ignore the forecast!

Postby drossall » 7 Jun 2019, 10:47pm

We liked it too, and the cheese is pretty good!