The 528 Thickness Line - again!
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The 528 Thickness Line - again!
It's that time of year again when the 528 thickness line appears around Europe on the forecast surface charts - or at least those produced by the UK Met Office.
But can anyone explain why the thickness lines only appear on the charts valid for 36hrs or more ahead and not on the current ones when there are patently signs that they would be there if 'enabled'.
The Uk Met Office website only explains what they are and not when, in time, they will appear.
Cheers all
mcdhu
But can anyone explain why the thickness lines only appear on the charts valid for 36hrs or more ahead and not on the current ones when there are patently signs that they would be there if 'enabled'.
The Uk Met Office website only explains what they are and not when, in time, they will appear.
Cheers all
mcdhu
Warning Toxic!
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Someone's got to ask. What is the '528 thickness line', and would I know it if I saw it. Come on- I want a diagram with a Dibnah-like 'demonsteraertion'!
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According to metoffice website:
As to the original question - not a clue! 
Thickness lines
Pressure decreases with altitude, and thickness measures the difference in height between two standard pressure levels in the atmosphere. It is proportional to the mean temperature of this layer of air, so is a useful way of describing the temperature of an airmass.
Weather charts commonly show contour lines of 1,000-500 hPa thickness, which represent the depth (in decametres, where 1 dam = 10 m) of the layer between the 1,000 hPa and 500 hPa pressure levels. Cold, polar air has low thickness, and values of 528 dam or less frequently bring snow to the UK. Conversely, warm, tropical air has high thickness, and values in excess of 564 dam across the UK often indicate a heatwave.
Pressure decreases with altitude, and thickness measures the difference in height between two standard pressure levels in the atmosphere. It is proportional to the mean temperature of this layer of air, so is a useful way of describing the temperature of an airmass.
Weather charts commonly show contour lines of 1,000-500 hPa thickness, which represent the depth (in decametres, where 1 dam = 10 m) of the layer between the 1,000 hPa and 500 hPa pressure levels. Cold, polar air has low thickness, and values of 528 dam or less frequently bring snow to the UK. Conversely, warm, tropical air has high thickness, and values in excess of 564 dam across the UK often indicate a heatwave.
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With that new knowledge I dash to the met charts and hey presto it'll snow from Wednesday p.m. until Friday a.m. from BHX eastwards. Now where did I put that seaweed.
No idea what the answer to the original question is though.
No idea what the answer to the original question is though.
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You're spot on there Lurkio! Here's their reply:
Cheers all
mcdhu
The reason is a historical one, and we have never done it before T+36. It is only now that the charts are broadcast on the web that people notice that some things are not there , like the thickness lines at T+24.
I will pass on your comments to our developers and forecasters and see if they can change it in the future.
I hope this helps.
I will pass on your comments to our developers and forecasters and see if they can change it in the future.
I hope this helps.
mcdhu
