**THE** official weather question thread.

[MAXUM]

OK since I'm the one asking all the questions, figure it's time to start an official weather question thread because I don't know about anyone else but I find the weather and more so the forecasting fascinating.

So here goes the first official question. I understand that certain ingredients are necessary for a storm to form. One thing really baffles me though, and that is the how atmospheric pressure works or changes. So typically a storm is centered around an area of low pressure. Why? How come a storm can't form under high pressure conditions? What is the key ingredient which controls fluctuation in pressures?

Oh and before I forget, a big thanks to CanisLupusArctos for all the wonderful answers provided thus far in the nor easter thread, those took some time to put together and I certainly appreciate the lesson and humor :-)