I have some further thoughts actually. I'm not certain, but I think that some people who are sensitive to barometric pressure changes are also prone to have S.A.D.--Season Affective Disorder. People with SAD become particularly depressed during the winter as the amount of sunlight each day wanes (some people actually have reverse SAD and become depressed during the summer due to the greater sunlight). Some people experience this on a smaller scale, becoming depressed when there's a patch of overcast or rainy days--or even just from one sunless day. As you probably know, depression is closely linked to headache disorders--migraines can cause depression and, in turn, depression may worsen, or even cause, migraines.
One theory about the cause of SAD suggests that a serotonin imbalance may lead to SAD's symptoms. Of course, serotonin is thought to play a vital role in migraines as well. Anyway, some treatments for SAD are: bright light therapy, increased exercise (particularly outdoors), and antidepressant medications such as SSRIs and atyprical antidepressants like Bupropion. If you experience the symptoms of SAD, I think it's possible that its common treatments may help your headaches.
However, in my last post, I asserted that knowing the triggers for your headaches usually doesn't help to pinpoint a specific treatment. Even though pressure change seems to be the primary cause of your migraines, most likely the biggest reason that a neurologist won't be able to treat you specifically for "what's actually happening" is because he or she (and indeed the entire medical field) doesn't really know what's actually happening. This is why we must go through trial and error. To take a quote from the Mayo Clinic about your specific condition:
"Study results indicate that some people who have migraines appear to be more sensitive to weather changes, such as changes in weather patterns, temperature, absolute humidity and barometric pressure. The mechanism by which these factors may trigger migraines in these individuals isn't known...There's no clear evidence of a link between weather changes and other types of headaches."
Anyhow, I hope that my ideas help in some way or another.
I have barametric migraines and SAD. I live way up North where we are pretty familiar with SAD and have worked with a naturalpath to deal with these things. SAD is actually a Vit D deficiency. I have been on mega doses of Vit D this year and have had no problem at all with SAD. I do however still have the migraines. I take Imitrex and it works great.