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James M

The Jet Stream and Us

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I was wondering if any caught this documentary on BBC4 last night? It looks quite interesting. I missed it but it is repeated on Wednesday 9.30pm.

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I was wondering if any caught this documentary on BBC4 last night? It looks quite interesting. I missed it but it is repeated on Wednesday 9.30pm.

Hi james. I don't know how much you already know, but if you have a reasonable knowledge don't expect to learn anything new. There was a lot of "dead time" for me throughout the programme regarding the history of discovery, but I suppose it would be the most interesting part for the general viewer.

One or 2 glaring inaccuracies too, but you'll spot them as it goes along. Not a wasted hour though by any means.

Dave

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Hi james. I don't know how much you already know, but if you have a reasonable knowledge don't expect to learn anything new. There was a lot of "dead time" for me throughout the programme regarding the history of discovery, but I suppose it would be the most interesting part for the general viewer.

One or 2 glaring inaccuracies too, but you'll spot them as it goes along. Not a wasted hour though by any means.

Dave

Hi Dave - can you tell me what you think the glaring inaccuracies were? I noticed a couple of things which I thought looked a bit shady but I want to be sure I heard them right before getting too grumpy :good:

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read out guides or try this site

http://booty.org.uk/booty.weather/metindex.htm

click on the relevant letter and scroll to jets

Ta for that!

For the record I thought that two of the 'mistakes' where that there was one jet in the northern hemisphere, starting in Africa and spiralling north and that the jet 'ended' over the UK.

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as you will see in the link there are almost always 2 jets in the northern hemisphere at this time of year

1=polar front jet which usually is reasonable for much of our weather

2=sub tropical jet which you can also sometimes see on the nw msl and jet charts, well south of the UK. I did not see the programme, perhaps they commented about them both.

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Hi Dave - can you tell me what you think the glaring inaccuracies were? I noticed a couple of things which I thought looked a bit shady but I want to be sure I heard them right before getting too grumpy :good:

I thing they've been summed up saying only 1 jet & that ( very mysteriously) it ended over the UK! There was something else which made me say something, but I've completely forgotten what it was now! I'll have to watch again & see what it was.

I was also concerned by the continued Michael Fish bashing! The poor bugger only presented a forecast based on the info supplied to him & what the point of dragging the 87 storm up again was completely lost on me.

Dave

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as you will see in the link there are almost always 2 jets in the northern hemisphere at this time of year

1=polar front jet which usually is repsonible for much of our weather

2=sub tropical jet which you can aslo sometimes see on the nw msl and jet charts, well south of the uk. I did not see the programme, perhaps they commented about them both.

Technically, there are several Jet Streams are there not, (Jet Streaks), in the Northern Hemisphere alone, i suspect that only in times of global zonality would there be as few as one, or two Jet Streams.

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Technically, there are several Jet Streams are there not

there are as the link shows

there can be confusion between what are jet streaks and what are jet streams

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jetlk4.jpg

Can anyone say what this means? Polar Jet to the South, Subtropical Jet to the North?

(from www.weatherzone.com.au)

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just about right I would think

Do you think this is a more interesting set up?

jetstreamwg9.jpg

One jet is around about 38S, the other maybe 47/48S. I guess it is not normal for them to be so close together.

What sort of implications would this have for the weather?

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there is surface high pressure shown between the two jets so the weather there would be fairly settled. More unsettled either side of the jets to the north of the sub tropical type and south of the polar.

Is that a diagram or an actual chart?

on this actual forecast chart for today, a significant weather chart for commercial flying, you can see that it can be even more complicated than what you showed.

post-847-1203411973_thumb.jpg

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there is surface high pressure shown between the two jets so the weather there would be fairly settled. More unsettled either side of the jets to the north of the sub tropical type and south of the polar.

Is that a diagram or an actual chart?

on this actual forecast chart for today, a significant weather chart for commercial flying, you can see that it can be even more complicated than what you showed.

post-847-1203411973_thumb.jpg

It's a diagram I assume just for the general public, but why they label jet streams on them I don't know.

On the chart you showed- big triangle = 50kt, long line = 10kt and short line = 5kt?

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its standard ICAO(International Civil Aviation Organisation) notation and indeed any Met office within the WMO(World Meteorological organisation)

triangle=50 knots

1 feather=10 knots

1/2 feather=5 knots

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you're right john about the chart being complicated :doh:

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its standard ICAO(International Civil Aviation Organisation) notation and indeed any Met office within the WMO(World Meteorological organisation)

triangle=50 knots

1 feather=10 knots

1/2 feather=5 knots

OOC, how do they obtain the wind speeds for that high up? I am guessing that geostrophic and gradient wind theory only works roughly at sea level, so is there a way of modelling jet streams, or is it all observational data from balloons (or the like)?

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Was an interesting aside comment made by the BBC Forecaster Kirsty McCabe, in that she acknowledged that here in the UK tv foreacsts do not mention global systems like the Jet Stream as 'we don't credit the public with much weather knowledge', whilst pointing out that it is frequently referred to in forecasts in the US. She hinted that they want to introduce such references 'gradually' over time...

I wonder if the fightback against dumbing-down is on the horizon?!

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Was an interesting aside comment made by the BBC Forecaster Kirsty McCabe, in that she acknowledged that here in the UK tv foreacsts do not mention global systems like the Jet Stream as 'we don't credit the public with much weather knowledge', whilst pointing out that it is frequently referred to in forecasts in the US. She hinted that they want to introduce such references 'gradually' over time...

I wonder if the fightback against dumbing-down is on the horizon?!

I noted in last years autumnwatch series the BBC used terminology including the 'jet stream' to help describe the reasoning behind Summer 2007 synoptics. The jet stream was shown diagramatically with its average position drawn on to show its southerly path across the country.

I think it helped immensely in building up people's weather knowledge as to why the summer was such a wet and unsettled one.

I look forward to such terminology being brought back into the BBC weather forecasts. Such terminology used to be common place. I note from watching a clip on youtube that much more 'detailed' terminology such as 'omega block' used to be used back in the 80's.

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Was an interesting aside comment made by the BBC Forecaster Kirsty McCabe, in that she acknowledged that here in the UK tv foreacsts do not mention global systems like the Jet Stream as 'we don't credit the public with much weather knowledge', whilst pointing out that it is frequently referred to in forecasts in the US. She hinted that they want to introduce such references 'gradually' over time...

I wonder if the fightback against dumbing-down is on the horizon?!

Top and bottom of it Shuggs average Joe on the street dont realize the complexity

of the weather, introducing other features such as mentioned would only confuse

most of em even more..!! Sure would benefit the likes of us so on a totally selfish point its a great

idea.. maybe such a move might get more people interested in the dynamics of the weather who knows.??

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I wonder if the fightback against dumbing-down is on the horizon?!

I hope so - how are people suppossed to learn or be interested if you never mention something

And for dumbed down we have ITV

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I hope so - how are people suppossed to learn or be interested if you never mention something

And for dumbed down we have ITV

Not much chance of that I would have thought. The growing army of weather "presenters" rather than forecasters gives you the answer. The days of forecasters presenting the BBC weather at all seem to be numbered.

And, before anyone jumps down my throat, I know they have to do a meteorology course, but do you really believe many of them know more about the weather than many of us on here? :lol:

Dave

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In case some members missed the programme, you can see it using the BBC iplayer on this link- The Jet Stream And Us BBC iPlayer

Definitely a good watch for the newbies, I agree with the comments above regarding inaccuracies, however on the whole i thought it was one of the better docs regarding weather/climate change in the last while.

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Was an interesting aside comment made by the BBC Forecaster Kirsty McCabe, in that she acknowledged that here in the UK tv foreacsts do not mention global systems like the Jet Stream as 'we don't credit the public with much weather knowledge', whilst pointing out that it is frequently referred to in forecasts in the US. She hinted that they want to introduce such references 'gradually' over time...

I wonder if the fightback against dumbing-down is on the horizon?!

I hope so, Shuggs, I hope so. I've always thought that perhaps they could put a more detailed (say 15 minutes/day) slot on one of their other channels which details all the stuff that we'd find interesting.

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