I seem to have suffered more than my usual share of migraines recently (this is post-migraine-induced nap). I'm still working on the triggers...as I mentioned in an old post, the big trigger for me is bright light/eyestrain. It's usually compounded by dehydration or poor eating habits; for example, eating donuts for breakfast.
A friend of mine in grad school got similar migraines, and she thought that pressure changes had a lot to do with it. I realized that I did indeed tend to get migraines when a warm front moves through.
I'm relatively lucky because I can treat my migraines with simple OTC stuff, as long as I take it as soon as I start to feel draggy/headachy. But my mother, who I've inherited my migraines from, insists that they get steadily worse over time. Not something I'm looking forward to.