Low Pressure Energy TransferAdded : Tuesday at 9:38 Oh great! Another heavy discussion Metcheck! What are you trying to do to my head this early in the day? Don't worry, it's not a full on meteorological discussion today, but instead we have a decent example of this in the charts, so thought it might be worth a closer look.
Take a look at the chart for Thursday :-
You can see a developing area of low pressure to the Southwest of the UK and might be tricked into thinking that this will develop into a potent secondary low pressure system with heavy rain and strong winds, but then look 24 hours later :-
Where's it gone? In fact, it stays as a secondary low and a trough as it crosses the UK and instead we have a developing Atlantic system just to the West of the UK.
You see, when you get two weather systems or two frontal systems which are close to each other, then the energy will always go into the one behind which is heading in. The reason is down to the upper air.
If you take a look at the jet stream for Thursday :-
You can see that the low pressure system was sitting on the exit of the jet stream. But, the new low pressure system coming in creates a trough in the jet stream which you can see South of Greenland. This in turn twists the axis of the jet stream and the previous low pressure now sits under a ridge which stops the development of it.
Then on Friday, the developing low pressure system has the trough all to itself :-
For low pressure and frontal systems to remain active and intense, they need this troughing in the upper atmosphere in order to create vorticity or spin. But, if another system rattles in from behind then it relaxes the trough and the system ahead loses the potential energy which it once had available.
If you are ever at the beach and bored of looking at ice cream and ships in the distance then just watch the waves. You'll notice how when they are spaced out everything is normal and lovely with one wave coming in after another. But if you see one wave catching up with the one in front of it then notice how the one ahead dies away and instead you end up with one larger wave created by the one behind.
METEOROLOGIST : MARSH |