Sqiggly Line

[MarkJohnson12345]

Looking at the 7 day forecast in the page below, amongst the isobars there is a line which seems to go in all directions with a number 546 in it.

What does this line represent??


http://www.westwind.ch/?link=ukmb,http://www2.wetter3.de/Fax/,.gif,br...+96,bracknell+108,bracknell+120,bracknell+132

Regards

 

[landaftaf]

unfortunatly I am unable to access the map you refer too - can you put it in a link ?
but shooting from the hip - and blindfold, it sounds like the jet stream, something we dont get given by our met boys for some reason ....

 

[Roberto]

Mark,

I cannot see the chart either, anyway being marked 546 it is most likely a thickness curve line, it represents thickness of the atmosphere.

Imagine sending a recording balloon witha barometer from earth level up in the sky, and measuring at what heights it reads 1000mb and 500mb, compute the difference between the two and you have 1000-500mb thickness. The figure on the chart takes off the final zero, so 546 means 5460m.

Briefly, thickness gives an indication of the average temperature of the atmosphere, the higher the reading, the warmer the column of air where the reading is taken.

What are they used for?
Basically
1.Determining mean virtual temperature advection, warm or cold air advection: if geostrophic wind pushes lower thickness values into an area with higher thickness, you have cold temperature advection (and vice versa)
2.Determining the position of surface fronts: where thickness lines are packed there is a strong temperature variation, that is often a front. The chart you see is poor in detail, if you look at thickness charts here

https://www.fnmoc.navy.mil/mywxmap/login.do?username=guest

you can see many more thickness isopleths (curves joining points having the same thickness) and check that most often where lines are packed there is an underlying front

3.Intensity of fronts: the nearer the thickness lines in a front, the higher the temperature variation, the strongest the front

4.Together with isobars, they are useful to determine areas of frontolysis or frontogenesis, areas where a front is likely to build or weaken

5.Also, in winter, if thickness is above 540dam there is usually rain, if lower usually frozen precipitations


hope this helps

rob

 

[MarkJohnson12345]

Try this part of the link!

http://www2.wetter3.de/Fax/,.gif,bracknell+00,bracknell+24,bracknell+36,bracknell+48,bracknell+60,bracknell+72,bracknell+84,bracknell+96,bracknell+108,bracknell+120,bracknell+132

Is the information of use to us mariners?

Regards

 

[MarkJohnson12345]

The link is as the first one written, but without the break. For some reason there is an odd character after the "?".

If you copy the whole line from beginning to end then paste it onto the address bar, you will see a 7 day animation.

Sorry not to get it right. (computer twud)

regards