[Convective / Storm Discussion Thread - 31st May 2017 onwards]

The elevated storms from the Spanish plume on Sunday night provided large amounts of rain.The Spanis plume is always described as being dry and originatin in N Africa and Spain.How does it get moistened to be able to produce such active storms?

[SE & East Anglia Regional Weather Discussion 12/1/2017 11z ---->]

 

I remember reading a letter by F E Lumb in Weather about the”snowless easterlies of March 1987 and I think it explains why the cold spell has not been quite as expected by many of us.The anticyclonic inversion has been at 850 mb.Low cloud formed over the North sea and was trapped by the inversion limiting any instability. More importantly the gain of heat and water vapour from the North Sea was distributed by convection and turbulence through a shallow restricted layer. This made the warming and moistening more efficient. Result gloom drizzle high RH and temperatures just around or above freezing.

In jan 87 deep cold air invaded England . Deeper convection occurred and the heating and moistening was distributed through a greater depth of the atmosphere and the rise in temperatures and due point was much less resulting in a memorable cold spell.

[What is the 'Shapiro-Keyser' cyclone model?]

I love to see pictures-just found this which for me brings it to life.

 

http://www.eumetrain.org/data/2/292/292.pdf

[What is the 'Shapiro-Keyser' cyclone model?]

Thanks -that's set me on the right track!!

[What is the 'Shapiro-Keyser' cyclone model?]

What is the 'Shapiro-Keyser' cyclone model?

This term keeps coming up in fora. What are these and why do they form?I'd love a clear explanation.