PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   The 528 Thickness Line - again! (https://www.pprune.org/tech-log/354109-528-thickness-line-again.html)

mcdhu 9th Dec 2008 09:46

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

Rainboe 9th Dec 2008 14:11

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'!

TCXCadet 9th Dec 2008 14:53

According to metoffice website:


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.
As to the original question - not a clue! :}

lurkio 9th Dec 2008 15:03

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.

Storminnorm 9th Dec 2008 15:15

Perhaps the 528 thickness lines appear when the Met
people are, shall we say, making a bit of a GUESS?

411A 9th Dec 2008 15:27


...making a bit of a GUESS?
IE; aka, forecast.:}

mcdhu 10th Dec 2008 08:32

OK, I give up. I'll try to contact the Met Office at Exeter - not holding my breath!

Cheers
mcdhu

lurkio 10th Dec 2008 09:49

Do so, they are very helpful. They answered my last question very quickly.

mcdhu 11th Dec 2008 07:34

You're spot on there Lurkio! Here's their reply:


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.
Cheers all
mcdhu

ROSUN 12th Dec 2008 09:23

411A
aka: What would have happened if what did happen didn't!


All times are GMT. The time now is 12:30.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.