Isobar Spacing On Bbc Weather

[Rev. Green]

What is the spacing of isobars on BBC Weather? Is it always the same? It seems about four millibars.

[10ClarionSt]

Rev., this is a good question and one which has recently been much on my mind. But I still don't know the answer.

[dannyk13]

Surely it varies with any changes in pressure?

[Old_Geezer]

Yeah, about 3".

No, no idea re bars.

[Old_Geezer]

https://www.bbc.co.uk/weather/about/18984103
4 millibars

[dannyk13]

https://www.dictionary.com/browse/isobar

[hellywelly4]

I'm not sure I understand the question, but if the isobars are very close together it means that it's going to be very windy; wider apart means calmer weather. Is that what you mean?

[Rev. Green]

Yes, Hellywelly, you are correct, but only if the isobars have constant spacing, as OldGeezer has shown. Without constant spacing, calm weather could have closely spaced isobars representing one millibar difference, and wild weather could have widely spaced isobars representing fifty millibars difference. That's why all charts should show the scale. Thank you everyone, I need only to find why the Mersey is shown completely silted, and I'll be happy!