These lines are not seldom. But mostly you see them during the summer time, and then often preceeding cold fronts. These are classical conv.lines.
The lines over the North Sea few days ago are more or less cloud streets. They are induced by very cold air flowing first over the Baltic Sea and then the N.S. And some of the streets develop into shower lines (convergence at the surface, divergence at altitude). You have the moisture and the energy over the water. The pronounced line in the above picture is probably further enhanced by orographic influence – Denmark, Norway. The flow is accelarated over the skagerrak (less friction) which in turn leads to more energy exchange making bigger shower lines. My theory…
Karl_Acht wrote:
These lines are not seldom.
When you say that, are you referring to the UK Met office MSLP charts or to some other publisher’s charts? I ask as I’ve not seen them on the UK MO MSLP charts, and I use them regularly. But I could well imagine that some other met office regularly publishes charts with them shown.
I saw one on the UK Met a few years ago, and found on the site what it was. When these latest ones appeared, I’d forgotten, and couldn’t find the symbol in the UK site. I gave up until this thread re-educated me.
dublinpilot wrote:
are you referring to the UK Met office MSLP charts or to some other publisher’s charts?
I’m referring to the UK Met office MSLP charts. Wait until summer and you will see (France, Germany)
