Help To Understand Charts.

[Backtrack]

Hi, i always see model output discussions which get very popular, They always say the last run this and that, But i don't understand any of the charts at all. I know they are wetnezzdale thats it, I want a career in meteorolgy so please can someone help me? I would be ever so thankful

Thank you

Jordan.

[Azores Hi]

Hi, i always see model output discussions which get very popular, They always say the last run this and that, But i don't understand any of the charts at all. I know they are wetnezzdale thats it, I want a career in meteorolgy so please can someone help me? I would be ever so thankful

Thank you

Jordan.

Hi Jordan.

Best place to start is here.

Learners area

In there you will find the netweather guides.

Go to the second page of the netweather guides and you will find a whole host of chart guides. Here's one which is a good introduction.

Guide to....charts

If I had more time I would post up more links but this is a good place to find your feet. You've done the most important step already. You joined Netweather!!!

My only parting advice is to carry on following the model output discussion. Click on the links people post up and have a look for yourself. Trust me, once you begin to understand it gets very addictive.

Best of luck matey!

Edited November 5, 2008 by Azores Hi

[Nick L]

Yeah, I was lost myself at first, but if you just keep following the Model Thread, it helps, believe me. Many people post a chart on there and say why they post it (for example, it shows a cold forecast), and after a while, you can see what a cold chart looks like for the UK.

[Backtrack]

Thank you very much guys, You have helped me greatly. I will go through these links and read. Thank you

SS

[Backtrack]

Right let me see if i got this right, I think i recognise the cold and warm fronts also pressure now, Go to here http://www.netweather.tv/index.cgi?action=nwdc;sess= click on number 42 and that shows a cold front just entering Ireland, Please can someone tell me if im right

Cheers

SS

Edited November 5, 2008 by Snow-Storm

[cheeky_monkey]

Right let me see if i got this right, I think i recognise the cold and warm fronts also pressure now, Go to here http://www.netweather.tv/index.cgi?action=nwdc;sess= click on number 42 and that shows a cold front just entering Ireland, Please can someone tell me if im right

Cheers

SS

there are no fronts drawn oh these charts..jus shows isobars...and pressure values

[Backtrack]

there are no fronts drawn oh these charts..jus shows isobars...and pressure values

Damn, Well thats cooler air isn't it? thats a cooler air mass? because the lower pressure is in the center and according to the met office guide to understanding charts (as rubbish as it is) low pressure with high pressure surronding is colder weather.

SS

Edited November 5, 2008 by Snow-Storm

[cheeky_monkey]

still..there are no fronts drawn....warm fronts are a black line with red semi circles..and cold fronts are black line with blue triangles

[Backtrack]

still..there are no fronts drawn....warm fronts are a black line with red semi circles..and cold fronts are black line with blue triangles

But i'm saying that thats colder air, I got it wrong first time but now i'm confused  http://www.metoffice.gov.uk/education/curriculum/lesson_plans/weathercharts/partb.html

[Nick L]

But i'm saying that thats colder air, I got it wrong first time but now i'm confused http://www.metoffice.gov.uk/education/curr...arts/partb.html

Those charts only show pressure - higher pressure prevents evaporation and convection so we get little or no rainfall. Lower air pressure means that evaporation and convection is much easier, allowing more rainfall.

Take this for example from the Met Office. This shows (roughly anyway) where the boundaries of cooler and warmer air masses are. That blue line with triangles over the UK is a cold front which brings cloud and rain, followed by cooler conditions. If that were a warm front, warmer conditions would follow.

Hope this helps (and please somebody point out if I make a mistake, so I can blame my Geography teacher who calls me Victor Meldrew =])

[cheeky_monkey]

Those charts only show pressure - higher pressure prevents evaporation and convection so we get little or no rainfall. Lower air pressure means that evaporation and convection is much easier, allowing more rainfall.

Take this for example from the Met Office. This shows (roughly anyway) where the boundaries of cooler and warmer air masses are. That blue line with triangles over the UK is a cold front which brings cloud and rain, followed by cooler conditions. If that were a warm front, warmer conditions would follow.

Hope this helps (and please somebody point out if I make a mistake, so I can blame my Geography teacher who calls me Victor Meldrew =])

and the purple is an occlusion or occluded front..where the cold front has caught up with the warm front forming an occluded front...usually show with red semi circles and blue trianlges together

[Nick L]

Oops, yes I missed the occluded front, thanks for that.

[Backtrack]

Ahh cheers guys, now i understand pressure. now it's just the other 10 or so charts can someone please link me to a site where i can learn about the main charts used? Thanks in advance.

SS

Edited November 5, 2008 by Snow-Storm

[Azores Hi]

Ahh cheers guys, now i understand pressure. now it's just the other 10 or so charts can someone please link me to a site where i can learn about the main charts used? Thanks in advance.

SS

Ok, lets get back to basics! Here is a little excercise to try, it should help you begin to interpret some of the charts.

Go back to that link you posted earlier.

here it is

Now, the defualt setting shows a map of europe and the north Atlantic. It is a simple map showing lines of equal pressure at sea level.

Underneath the Netweather logo and above the numbers you will find a drop down menu next to "select map type to display". Click on that menu.

From here you can select the different map types. The best way to learn is to compare one map to another, so lets choose something simple first.

Select "north atlantic precipitation"

Hopefully you will be able to relate the sea level pressure from the first map to precipitation. You should notice how precipitation ( the blue stuff ) and low pressure are closely related. Scroll through a few charts in succession and you will see the bands of precipitation move in relation to the areas of moving low pressure.

Incidentally, the numbers relate to the numbers of hours in the future after the model run.

Ok lets try one more.

Select the map called "850hpa Temps +SLP"

Translated means- The temperature in C at an air pressure of 850 Hpa, this is indicated by the different colours, blue being cold and yellow/ orange is warm. Roughly speaking the 850 hpa height is 1000 ft and you can add about 10 C to that temp to get SLP Temp (Temperature at sea level)

So for a good chance of snow. That 850 Hpa temperature should be at least -5C, (-8 or -10 is much better though )

There are loads of other charts there to scroll through, and to be honest, I don't fully understand half of them :lol:

But that should get you started. Remember, compare the charts you do understand to the ones you don't. The best way to learn by far!

I've tried to keep it simple, hopefully not so simple that you are offended!

[Backtrack]

Ok, lets get back to basics! Here is a little excercise to try, it should help you begin to interpret some of the charts.

Go back to that link you posted earlier.

here it is

Now, the defualt setting shows a map of europe and the north Atlantic. It is a simple map showing lines of equal pressure at sea level.

Underneath the Netweather logo and above the numbers you will find a drop down menu next to "select map type to display". Click on that menu.

From here you can select the different map types. The best way to learn is to compare one map to another, so lets choose something simple first.

Select "north atlantic precipitation"

Hopefully you will be able to relate the sea level pressure from the first map to precipitation. You should notice how precipitation ( the blue stuff ) and low pressure are closely related. Scroll through a few charts in succession and you will see the bands of precipitation move in relation to the areas of moving low pressure.

Incidentally, the numbers relate to the numbers of hours in the future after the model run.

Ok lets try one more.

Select the map called "850hpa Temps +SLP"

Translated means- The temperature in C at an air pressure of 850 Hpa, this is indicated by the different colours, blue being cold and yellow/ orange is warm. Roughly speaking the 850 hpa height is 1000 ft and you can add about 10 C to that temp to get SLP Temp (Temperature at sea level)

So for a good chance of snow. That 850 Hpa temperature should be at least -5C, (-8 or -10 is much better though )

There are loads of other charts there to scroll through, and to be honest, I don't fully understand half of them

But that should get you started. Remember, compare the charts you do understand to the ones you don't. The best way to learn by far!

I've tried to keep it simple, hopefully not so simple that you are offended!

:o Azores i am gonna be your best friend forever, I ACTUALLY UNDERSTAND THE ONES YOU EXPLAINED! (lets have a party now) Thank you for taking the time to post this and no you didn't offend me. Thank you soooo much

SS

Edit: I only have one question, What when there is no number there to tell you the temperature? On some there is just how high the pressure is how can we tell then?

Also if you scroll through, click on number 57, this is colder weather am i right? http://www.netweather.tv/index.cgi?action=nwdc;sess=

SS

Edited November 6, 2008 by Snow-Storm

[Azores Hi]

:Edit: I only have one question, What when there is no number there to tell you the temperature? On some there is just how high the pressure is how can we tell then?

Also if you scroll through, click on number 57, this is colder weather am i right? http://www.netweather.tv/index.cgi?action=nwdc;sess=

SS

Find euro temps or Uk Max temps on the dropdown menu for temperature info. The chart you indicated showed relatively cool-average weather, but not cold. In fact it showed the storm brewing for this weekend. 3am Sat morning.

Those blue colours on the map do not indicate temperature. Rather they indicate the height above sea level where the air pressure is at 500hpa (please someone correct me if I'm wrong here).

SS, I think you would be better off reading through those links I provided which directs you the the explanation of charts in the learners area, as my knowledge is painfully lacking

[Backtrack]

Okiee Dokiee thanks again for taking the time to reply and answer my question

SS

[Backtrack]

Is it true the higher the pressure the warmer? And the lower the colder?

SS

[Geordiesnow]

Is it true the higher the pressure the warmer? And the lower the colder?

SS

Not exactly, it all depends on the set up whether high pressure contain mild or cold temps.

If we get high pressure nudging in after a Northerly, then more often than not the high pressure can bring low day time temps and very low minimum tempertures because of clear skies at night.

Of corse it depends on the time of year, if we get high pressure in winter following a Northerly then it will be a cold high but if we get it in summer, then it can lead to very warm tempertures.

I'm sure someone can explain it better than me though.

[Backtrack]

Thank you georodiesnow

SS

[Geordiesnow]

Forgot to menturn in my last post, even in winter high pressure can bring mild temps, if we get a bartlett type of high(where high pressure is in Western Europe), we get very mild SW'lies which bring mid teen tempertures even in December. Its not exactly high pressure type of weather as the winds are normally gusty and there can be quite abit of drizzle in Western areas.

[Icer]

I found this it is useful, click the face >>>>

Edited November 7, 2008 by Icer

[johnholmes]

a very good, and also a clever, link, Icer

[Nick L]

Have you taken GCSE Geography Snow-Storm? As most of the courses do contain an element of weather (moreso than the AS Level course I am taking ). Although most of the work we did is more or less completely covered in this thread and on the Met Office website.

[Backtrack]

Have you taken GCSE Geography Snow-Storm? As most of the courses do contain an element of weather (moreso than the AS Level course I am taking ). Although most of the work we did is more or less completely covered in this thread and on the Met Office website.

Hey nick, Yes i have taken geography, i love that subject, Problem is that he said because we have so much to cover he may have to skip the weather part out

SS

Edited November 8, 2008 by Snow-Storm