BBC Weather

[michael8554]

Predicting uninterrupted clear skies 1800 to 0500.

Looked out at 19:45.

100% Clouds.......

Michael

[Pete Presland]

My thoughts at around 6:30-7:00, clear again though 🙂 

[michael8554]

21:46, still "clear", still 100% cloud

Michael

[Mr Spock]

It says the same for here, but the map does at least have cloud on it. Clear Outside shows cloud, clearing about 2am.

[michael8554]

22:46, no change, still "clear to 05:00"

Many years ago I was working at Television Centre, in a windowless environment.

We'd surface for an evening meal in the airy canteen.

The weatherman appeared, he'd just recorded the late night weather report.

He looked out of the windows, put down his tray, and headed back downstairs.

It was snowing outside..........

Michael

 

[david_taurus83]

All the weather apps were wrong last night. An utter disappointment as it was nice and clear at sunset and I was banking on finishing an imaging project. Was clear when I started and clouded over before the first sub even finished! Even took my bins to the astro society and the club rolled out the big dob! Disappointment all round!

[Guest]

Predicting the weather...the one job you can completely get wrong and not get fired from.   

[Carbon Brush]

I sometimes think weather forecasters in certain other countries have a much easier time.

For example, if you are in a large continent size land mass, the patterns are more predictable and. Wind direction for example being almost seasonal in some parts of the world.
Also you can have a large number of permanent sensors/reporting stations.
In the UK, the large air masses to determine our weather can come from all corners of the compass, at any time of year. Then add in the jet stream.

When using weather apps or other predictions, it is important to remember that most are using the same data.
Then there are a few different computer models/prediction methods. But the same output is presented in many different formats.
By format I mean a cloud symbol with a % chance of rain. Or a grey bit on a screen, etc.
It is not surprising that everyone gets it wrong!

Another good source is airfield TAF (terminal area forecast) and METAR (meteorological actual).
These are based on the same data set for the whole UK, but tweaked by local knowledge - and someone looking up!
Aviation forecasts are of interest to the astro community.
The extent of cloud cover provides a pointer about whether there might be enough gaps to get a view.
Knowing about wind speed and gust gives an idea of tripod stability.
Probability of precipitation within a narrow time window helps answer if it is worth going outside.
Other aviation services provide information about upper air winds, which can affect seeing.

Off now to check the pine cones, and whether the ducks are nesting high up the pond embankment.
 

[Guest]

5 minutes ago, Carbon Brush said:

I sometimes think weather forecasters in certain other countries have a much easier time.

For example, if you are in a large continent size land mass, the patterns are more predictable and. Wind direction for example being almost seasonal in some parts of the world.
Also you can have a large number of permanent sensors/reporting stations.
In the UK, the large air masses to determine our weather can come from all corners of the compass, at any time of year. Then add in the jet stream.

When using weather apps or other predictions, it is important to remember that most are using the same data.
Then there are a few different computer models/prediction methods. But the same output is presented in many different formats.
By format I mean a cloud symbol with a % chance of rain. Or a grey bit on a screen, etc.
It is not surprising that everyone gets it wrong!

Another good source is airfield TAF (terminal area forecast) and METAR (meteorological actual).
These are based on the same data set for the whole UK, but tweaked by local knowledge - and someone looking up!
Aviation forecasts are of interest to the astro community.
The extent of cloud cover provides a pointer about whether there might be enough gaps to get a view.
Knowing about wind speed and gust gives an idea of tripod stability.
Probability of precipitation within a narrow time window helps answer if it is worth going outside.
Other aviation services provide information about upper air winds, which can affect seeing.

Off now to check the pine cones, and whether the ducks are nesting high up the pond embankment.
 

I don't know if I agree with that.  Ohio is one of those states, as is most of the Midwest, that if you don't like the weather wait five minutes and it will change.  I have seen all four seasons in one day before.  I really have no idea how they can predict that lol.

[Macavity]

My "Weather Forecast" (Android) APP seems to be pretty good?

I note that, it actually *sources* data from the UK "Met Office"...
Comprehensive maps of cloud/rain for (reasonable) predictions
on (admittedly) shorter time scales? 🤔

Aside: Apparently this town is known for it "Foehn Wind"...
I sense (like M.Caine) "Not a lot of people know that!"? 😅
 

Edited March 8, 2022 by Macavity

[Stephen_M]

15 minutes ago, Carbon Brush said:

Another good source is airfield TAF (terminal area forecast) and METAR (meteorological actual).
These are based on the same data set for the whole UK, but tweaked by local knowledge - and someone looking up!
Aviation forecasts are of interest to the astro community.
The extent of cloud cover provides a pointer about whether there might be enough gaps to get a view.
Knowing about wind speed and gust gives an idea of tripod stability.
Probability of precipitation within a narrow time window helps answer if it is worth going outside.
Other aviation services provide information about upper air winds, which can affect seeing.

Thanks for that. Living within 5 miles of Leeds Bradford I'll give this a try. Weather here seems very dependant on local conditions which I'm presuming is due to topography of the local hills and valleys. I've noticed that still clear nights are bad for observing due to mist forming in the valley, it seems here you need a gentle breeze for best conditions.

I get the cloud thing is frustrating, but presumably we're talking very fine margins of error within their models. So if they're tracking a cloud mass/weather front that's hundreds of km in length, even an error of a few percent will mean the predicted edge of it varies considerably compared to the eventual position in reality.

[Carbon Brush]

@Stephen_M Yes by all means give the LBA TAF a try.
Any TAF is difficult to read initially. They are based around abbreviatians made in the days of teleprinter services.
Here is the raw format for LBA today, valid till tomorrow midday.

EGNM 081101Z 0812/0912 14009KT 9999 FEW030 PROB30 TEMPO 0812/0817 15015G25KT PROB30 TEMPO 0817/0822 16015G25KT 8000 -RA BKN014 TEMPO 0822/0909 6000 BKN012 PROB30 TEMPO 0822/0909 BKN006 TEMPO 0906/0912 18015G25KT

EGNM is Leeds Bradford Airport. Issued at 08 (today) at 1101Z  (1101 local) valid for 0812/0912 (today till tomorrow midday)............🙄

Fortunately these days a lot of sites offer a translation

Here is one (there are others)   https://en.allmetsat.com/metar-taf/united-kingdom-ireland.php?icao=EGNM

Visibility means horizontal visibilty at or near the ground. Not vertical.
You could get 100M visibility reported due to low lying fog, but look up and see stars.

However, other data in there means they don't think it will be a good scope night.

HTH, David.

[shropshire lad]

Last night 7th March  Telford Shropshire area .... was clearish at 8pm and total cloud by 8:30 ... but still got this.

[Guest]

20 hours ago, shropshire lad said:

Last night 7th March  Telford Shropshire area .... was clearish at 8pm and total cloud by 8:30 ... but still got this.

I am in a darker area and wished my skies looked like that.  

[Second Time Around]

Some of you will be aware that I've been recording the accuracy of originally 6, now 7, forecasts of cloud cover.  See https://stargazerslounge.com/topic/376745-a-record-of-the-accuracy-of-my-local-cloud-forecasts/#comment-4189743

The results are so similar that I think it safe to say that there's no significant difference between the various forecasts.

I made the following comments on this topic in December:

Short term vs medium term forecasts

What is interesting from my research is that there are 2 methods of deriving forecasts. 

The one most of us will be familiar with is the medium term forecasts that we see on the TV and websites.  These are computer models looking perhaps up to 14 days ahead.  They're "driven by powerful numerical weather prediction (NWP) systems. By solving physical equations, NWPs provide essential planet-scale predictions several days ahead. However, they struggle to generate high-resolution predictions for short lead times under two hours." (My bold italics.)

The other type of forecast is a nowcast.  "Nowcasting is a technique used for very short-range forecasting. The current weather is mapped and then an estimate of its speed and direction of movement is used to forecast the weather a short period ahead (assuming the weather will move without significant changes). It takes time to gather and map weather observations, so a short forecast is needed to outline what the weather is currently. Nowcasts can be used as a source of detailed guidance on the location, extent and timing of imminent, often high impact weather events."

"The Met Office produce a routine delivered service for T+0 out to T+6 {hours}, for the United Kingdom, which blends our observations and UK Atmospheric Hi-Res model. At T+0 the blend is heavily weighted to observations and as time goes on the weighting of the UK Atmospheric Hi-Res model is increased, at T+6 the UK Atmospheric Hi-Res Model has the dominant weighting. The UK Atmospheric Hi-Res model is part of the Met Office flagship numerical weather prediction (NWP) model called the Unified Model. The resolution of the Nowcasting is comparable to radar data."

Nowcasting is of course what we need to decide whether to get our scopes out.  Unfortunately, nowcasting in its relative infancy.  AI is now being used to enhance its accuracy, for instance in tests that the Met Office is doing with Google's Deep Mind.  Hopefully, this will be of particular benefit to the likes of us.

In the meantime I'll continue to use these 6 cloud forecasts (with Good to Stargaze being added from next month).  

However, as I've mentioned elsewhere,  I also look at 2 other sites with satellite data.  The first is Zoom Earth for current cloud photos.  Unlike many sites it also shows cloud at night using infrared images, plus one can go back a long time.   Bear in mind though that low cloud and fog doesn't always show up on infrared images. But it often correctly shows that the only cloud in Kent is over our area, and that it's clear just a few miles away!

The other is Meteoradar as it extrapolates cloud satellite pictures to give nowcasts up to  3 hours ahead.   Unfortunately it does so only for daytime hours.  However, it's useful for soon after sunset, and also for solar observing.

 

How accurate are the current forecasts?

What will surprise many though is something I commented on in a topic where the OP was lamenting the accuracy of Clear Outside.  Even now, the current forecasts are pretty accurate.

Below are the figures for Clear Outside over the first 6 months of recording.  However, as I said, all the other forecasts will be very similar.

Correct 67%

Partly correct/partly wrong 29%

Totally wrong 4%

[Adreneline]

This site was recently brought to my attention and over the last six or so weeks has proved to be very helpful to me in prediciting up and coming 'on-the-day' clear skies and, maybe more importantly, up and coming 'whilst-the-gear-is-outside' cloud and rain.

https://www.weatherandradar.co.uk/weather-map?center=NaN,NaN&placemark=53.1736,0.0937&zoom=7.53&layer=wr

When comparing this site to CO for 'on the day forecasts' I have found this to be more accurate. As for looking to see if it is "going to be clear next Tuesday" - look elsewhere!

Apologies if folks are already well aware.

[Second Time Around]

19 minutes ago, Adreneline said:

This site was recently brought to my attention and over the last six or so weeks has proved to be very helpful to me in prediciting up and coming 'on-the-day' clear skies and, maybe more importantly, up and coming 'whilst-the-gear-is-outside' cloud and rain.

https://www.weatherandradar.co.uk/weather-map?center=NaN,NaN&placemark=53.1736,0.0937&zoom=7.53&layer=wr

When comparing this site to CO for 'on the day forecasts' I have found this to be more accurate. As for looking to see if it is "going to be clear next Tuesday" - look elsewhere!

Apologies if folks are already well aware.

Thanks for that  I very much like the graphics on this site and have bookmarked it.

One other site I didn't mention in my last post is http://www.wunderground.com  Quite apart from all its other forecasts, this is my favourite for short term rainfall predictions.  The reason is that, rather than just extrapolating the movement of rain and showers, it also takes into account that showers die out late in the day and overnight due to falling temperatures.

[Mr Spock]

Another ludicrous forecast for tonight. BBC shows 0% cloud, CO 100% (high) cloud. I quick look outside tells me yes, I can see the moon, but it's buried in high cloud. No observing tonight.

Hopefully tomorrow will be better.

[StuartT]

1 minute ago, Mr Spock said:

Another ludicrous forecast for tonight. BBC shows 0% cloud, CO 100% (high) cloud. I quick look outside tells me yes, I can see the moon, but it's buried in high cloud. No observing tonight.

Hopefully tomorrow will be better.

Yep. I just thought exactly the same. I have yet to find ANY weather forecasting site or app that is even remotely useful for astro. They are all absolute rubbish.

[Zermelo]

I've discovered a great new way to improve your weather - just switch the display setting in the website.

Things are looking a bit variable for this evening, when the view is centred on midday:

 

but on switching to "centre at midnight", suddenly it's all looking good:

The only downside is that the moon seems to be rising an hour earlier. Is it possibly showing me yesterday's weather?

 

 

 

Edited March 17, 2022 by Zermelo