Joe wrote in message . ..
The chicken or the egg?

Which came first? The low pressure or the storm?

The high pressure, the warm one over the azores and the cold one above
Canada/Grenland

In simple terms, help a dummy understand if the low pressure causes the storm,
or is the low pressure a byproduct of the storm?

Most often a byproduct if it's an extratopical storm, cold air
travelling south want to go to the east and warm air travelling north
want to go to the west, therefore a low pressure will build west of
the cold air going south and east of the warm air going north. (The
special geography and winds around Iceland often cause a stationary
low that traps extratropical lows)

http://www.eoascientific.com/campus/...ew_interactive
http://www.westwind.ch/?page=gfsm (slp h500; 10m winds; 850 hpa)

- The most nasty winds is often the northerly winds east of the low
and right before/after the cold front south and west of the low.

And why in the hell does the pressure rise and fall?

Often extratropical lows and the high pressure ridges between those.

Thanks,
Joe

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