Large Scale UpliftAdded : Wednesday at 12:55 When you think of thunderstorms then you might think of showers bubbling up during the day or perhaps air being forced to rise of mountains and higher ground. But there is another mechanism which we call Large Scale Uplift. This is exactly what it sounds like and where the atmosphere is forced to rise across a wide area.
This can be down to a couple of things, the first could be a frontal system or trough moving through, the other is where low pressure develops as air is taken out at height and this in turn creates low pressure and air nearer the surface is drawn in and rises en mass.
Today we have one such feature. If you take a look at the synoptics then you can see low pressure to the West and a trough running in from the Southwest :-
If you take a look at the jet stream then you can see the core running over this trough which provides some uplift, but notice the "kink" in the jet stream later this evening :-
This "kink" allows the jet stream to accelerate ahead of the kink and then slow down which in turn gives more energy and allows creates the large scale uplift. Think of it as a tube of glass with a ball at the bottom and then blowing over the top, the pressure falls near the top which in turn forces the ball to rise.
The process continues as the low pressure system develops and the GFS ► showing this as some heavy and thundery rain across Southeast and Eastern areas later this evening and overnight :-
Traditionally, you would expect the showers to die away in the evening as the power from the sunshine dwindles, but with large scale uplift, these features can continuing well into the evening and overnight as instead of being driven by thermal convection, the jet stream simply continues to bring large scale uplift as it moves Northeast.
METEOROLOGIST : MARSH |