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Questions for the Met Office please!


jamespels

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Hi all,

The Met Office will be joining us at Peak Star Party 2014 and want to know some of the "burning issues" that affect astronomers. Specifically, I have been asked for questions the presenter can prepare for and I thought I would open this up to the whole forum and will post answers back here after the event. Full details of the talk will be on the PSP website after this weekend.

Yes, I have taken the opportunity for a quick plug for PSP but this is a genuine post - I do want questions for the Met Office and I will post the answers back here...

Thanks,

James.

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Hi James,

I would like to understand the impact of aircraft pollution on high level cloud. There is some discussion going on about this elsewhere on the forum and it does seem to be more prevalent.

During the ash cloud flight ban, skies did seem to be very clear.....

Stu

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- Are we likely to get more cloudy nights as a result of climate change over the next couple of decades? (including any likely changes to the seasonal cycle in the UK).

- Can we be confident that advances in computing will lead to better forecasts of nocturnal cloud?

- Will the Met Office ever offer a forecast of astronomical seeing, which is related to atmospheric turbulence throughout the atmosphere?

it should be noted that there are other major reasons to care about nocturnal cloud, such as road freezing.

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Two I would have are:

1) What do the Met office interpret as "Clear". It is not I suspect what astronomers interpret as "Clear". Having an idea of what/how they catagorise conditions could help.

2) Can they display the Jetstream on the weather maps/charts more. It is highly relevant for conditions and general atmospheric stability.

You could enquire why the weather also seems to stop at 16:00 on just about every forecast I see on TV.

This one really bugs me, Is there not supposed to be weather in the evening, and therefore waht is No weather?

This however could be TV decision not the Met office.

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Two I would have are:

1) What do the Met office interpret as "Clear". It is not I suspect what astronomers interpret as "Clear". Having an idea of what/how they catagorise conditions could help.

2) Can they display the Jetstream on the weather maps/charts more. It is highly relevant for conditions and general atmospheric stability.

You could enquire why the weather also seems to stop at 16:00 on just about every forecast I see on TV.

This one really bugs me, Is there not supposed to be weather in the evening, and therefore waht is No weather?

This however could be TV decision not the Met office.

I'd certainly agree with point 1- the weather presenters idea of what 'clear skies' mean and mine are different......

'Clear' seems to cover anything between a layer of thin high cloud and the crystal skies we dream of!

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1. How about getting even the daily forecast right ? it is so often wrong just a couple of hours out that I am beginning to think it is a live feed; eg forecast; sunny, it starts to rain, check back and the forecast now states showers. Even more so in the evenings; the forecasted clear skies do not appear.

2. An option to see light cloud rather than thick or dense cloud when looking at the charts.

3. You know how we get UV indexes and Pollen count; would it be possible to get something similar for astronomers, a clarity or atmospherics index ?

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3. You know how we get UV indexes and Pollen count; would it be possible to get something similar for astronomers, a clarity or atmospherics index ?

You mean like the shipping visibility forecast

Shipping Visibility

Very poor Visibility less than 1,000 metres

Poor Visibility between 1,000 metres and 2 nautical miles

Moderate Visibility between 2 and 5 nautical miles

Good Visibility more than 5 nautical miles  

Astro Visibility

Very poor Leave scope inside- pour a glass of wine and go on SGL instead.

Poor Look out the window- but only in hope. Pour a glass of wine....

Moderate Get the scope out cooling. The cloud will arrive when it gets dark. Pour a glass of wine.....

Good Full moon. Pour a glass of wine.....

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Two I would have are:

1) What do the Met office interpret as "Clear". It is not I suspect what astronomers interpret as "Clear". Having an idea of what/how they catagorise conditions could help.

2) Can they display the Jetstream on the weather maps/charts more. It is highly relevant for conditions and general atmospheric stability.

You could enquire why the weather also seems to stop at 16:00 on just about every forecast I see on TV.

This one really bugs me, Is there not supposed to be weather in the evening, and therefore waht is No weather?

This however could be TV decision not the Met office.

I've never understood why the UK forecasts don't include jet stream info considering how much effect it has. Do they think people can't understand it?

Forecasts in the US include it all the time.

Sent from my iPad using Tapatalk

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Micheal Fish aside you might want to ask why the weather forecast seemed to be more accurate 20 years ago than it does today. And totally agree with above comments reagarding night forecasts, they might as well just say "and tonight it will be dark".

more like 'Tonight will be Dark-ish...'

ChrisH

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1) What do the Met office interpret as "Clear". It is not I suspect what astronomers interpret as "Clear". Having an idea of what/how they catagorise conditions could help.

Very good point - I live pretty close to Stoke on Trent and the LP from the city is quite useful for judging atmospheric conditions - on a truly dry night, there is very little glow and the Milky Way is naked eye visible; it doesn't seem to take much for the sky to turn quite orange and I can only assume this is down to atmospheric moisture reflecting the light. Tell me how humid the air is (must be forecastable, probably more easily than cloud cover as you don't need to consider dew points and so on) and I will have a pretty good idea what seeing will be like.

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I would like to know why they bother with long range forecast (3days or more) when they struggle to get it right within 12-24 hrs.

Also, are the premium (paid) services more accurate?

ChrisH

I use the paid services at work a lot.

They are more accurate in that they give the forecast (or indeed hindcast if required) for the exact location you specify and can be tailored to your needs.

Also it gives you 24hr access to a forecaster who you can call and ask questions to.

Seven day forecasts are demanded by industries that are weather dependant, it can be incredibly costly to get it wrong.

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

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If the questions are allowed to be off topic then, how about:

given the level of vitriol the Met Office attracts from the general public based on their subjective experience are they ever tempted to stop their outreach activities and public forecast services and deal only with professionals? :angel12: 

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I don't know if they'd answer, but why has the Met Office forecast/cloud conditions &c web site been down graded? 

Used to be able to get a reasonably quick rainfall chart or IR or visible cloud picture and work out if it was likely to be worth getting the scope out.  Now instead there's a ghastly, totally uninformative graphic which takes ages to load or reload, is covered with unneeded controls and doesn't animate and show anything.

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Just one question :

Why do weather forecasters keep using the word "changeable" instead of just saying "we don't really know so we will just say that word" :tongue:

They are two different things. Changeable means that one minute it will be sunny, and maybe half an hour later there could be a shower - hence change. Unfortunately, that's the basic attribute of british weather: it changes. :grin:

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Very good point - I live pretty close to Stoke on Trent and the LP from the city is quite useful for judging atmospheric conditions - on a truly dry night, there is very little glow and the Milky Way is naked eye visible; it doesn't seem to take much for the sky to turn quite orange and I can only assume this is down to atmospheric moisture reflecting the light. Tell me how humid the air is (must be forecastable, probably more easily than cloud cover as you don't need to consider dew points and so on) and I will have a pretty good idea what seeing will be like.

This data is already available from lots of websites. Simply look for relative humidity on the graphical time series or tabular type forecasts.

Anything around 80% or more is going to be hazy or misty. 90% and above is going to be very misty / low cloud forming / foggy.

You can also factor in the forecast temp to see just how humid it might be. This is because warmer air can hold more moisture with greater potential for dew and mist as the temps go down later on.

e.g. If the forecast temp in the evening is around 18c with say a dew point of around 16c (or around 80 percent relative humidity) dew and mist is likely to form. Especially so at this time of year as the sun goes down faster and the air cools quicker in the evenings.

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p.s. It actually is the dew point that determines how humid the air is. The relatively humidity which is what you can use to forecast the likelihood of mist forming, etc is the percentage of the actual air temp compared with the temp it will condense into water vapour (the dew point).

When the actual air temp drops quick enough to match the dew point temp, say 16 / 16c then dew and mist will form. That's why it's more likely when the two figures are close to each other.

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p.s. It actually is the dew point that determines how humid the air is. The relatively humidity which is what you can use to forecast the likelihood of mist forming, etc is the percentage of the actual air temp compared with the temp it will condense into water vapour (the dew point).

When the actual air temp drops quick enough to match the dew point temp, say 16 / 16c then dew and mist will form. That's why it's more likely when the two figures are close to each other.

Thanks for the explanation - I knew it was somewhere around there but it is good to have someone who knows what they are talking about rather than just using the right words and hoping nobody notices they make no sense in the given order (like me:))!

The real point still stands, though: I know I can find this information elsewhere (just like I could find out about the jet steam elsewhere) but it would be good to have it all together on the Met Office forecasts.

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Ok, had a chat with John (chap from the Met Office coming to PSP) and went through some of these questions. He is going to pass on any genuine complaints and is going to raise the whole astronomy forecast thing internally.

He has also agreed to tweak his PSP talk to include air mass theory which will help us interpret what pressure charts, etc are showing us to get more information from them.

More detailed answers to follow, probably after PSP.

One thing that might be worth kept an eye on - John will be preparing weekly forecasts for PSP in the run down, including the source information he has used and how he has interpreted it. Even if the forecast is a bit vague to start with, at least we will be able to see where it came from. I will post a link on here to the forecast page when we start.

Many thanks for the questions so far, and please keep them coming!

James.

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Hi all,

One answer from the Met Office regarding astronomy weather forecasts. They have sent me a link to this app which they endorse:http://www.metoffice.gov.uk/datapoint/showcase/scope-nights

John is interested in feedback from anybody who had used it.

I have asked about getting the same information added as a layer on their cloud / rain / weather infographic on their site - will keep you up to date on this.

James.

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I use scope nights but apart from its accuracy which is as good or bad as everything else it doesn't have the level of details some other sites have. Eg I like the information displayed here

https://www.meteoblue.com/en/great-britain/weather-billericay/seeing

Particularly the column displaying the the size in arc we could possibly see which i find is an easy measure to recognise how good the seeing is. It's also good that the level of seeing is independent of cloud cover. So something from the met office with this info would be great. All it needs is to add an animation like sat24 and it would be fairly comprehensive.

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